Light emitting device
阅读说明：本技术 发光装置 (Light emitting device ) 是由 刘建良 许明祺 廖世安 刘俊宏 叶志庭 叶昶腾 陈柏璋 邱圣哲 于 2016-12-30 设计创作，主要内容包括：本发明公开一种发光装置,其包含：一发光结构,具有一侧表面、一反射层覆盖侧表面。发光装置具有一第一发光角度及一第二发光角度。第一发光角度与第二发光角度的差值大于15度。(The invention discloses a light-emitting device, comprising: the light-emitting structure is provided with a side surface and a reflecting layer covering the side surface. The light-emitting device has a first light-emitting angle and a second light-emitting angle. The difference between the first light-emitting angle and the second light-emitting angle is larger than 15 degrees.)
1. A light-emitting device, comprising:
a carrier plate;
a light guide plate;
the light-emitting structure is positioned between the carrier plate and the light guide plate and is provided with an electrode, and the electrode is provided with a bottom surface;
a light-transmitting body which wraps the light-emitting structure and comprises a first side surface, a second side surface, a third side surface and a fourth side surface;
a reflective layer covering the first side surface and the third side surface, but not covering the second side surface and the fourth side surface;
an extended electrode having a top surface, the top surface being connected to the bottom surface of the electrode, and the top surface having a maximum width smaller than a maximum width of the bottom surface; and
a diffusion plate located on the light guide plate;
the light-emitting device has a first light-emitting angle in a first direction and a second light-emitting angle different from the first light-emitting angle in a second direction.
2. The light emitting device of claim 1, wherein the light transmissive body comprises an upper surface and the reflective layer comprises an inner surface inclined to the upper surface.
3. The light-emitting device of claim 1, wherein the light-transmissive body comprises an upper surface and a lower surface opposite to the upper surface, and the extended electrode is disposed below the lower surface.
4. The light-emitting device of claim 3, wherein the reflective layer comprises an inner surface comprising a first portion oblique to the upper surface and a second portion substantially perpendicular to the upper surface.
5. The light-emitting device of claim 1, wherein the first side surface and the third side surface are opposite to each other, and the second side surface and the fourth side surface are opposite to each other.
6. The light-emitting device according to claim 1, further comprising a reflector on the other side of the light guide plate opposite to the diffusion plate.
7. The light-emitting device of claim 1, wherein the reflector has a length greater than the light guide plate.
8. The light-emitting device of claim 1, wherein the light-emitting device comprises only three light-emitting surfaces.
9. The light-emitting device according to claim 1, wherein the extended electrode overlaps with the reflective layer.
10. The light-emitting device of claim 1, wherein the extended electrode has a side surface that is substantially coplanar with a side surface of the reflective layer.
Technical Field
The present invention relates to a light emitting device, and more particularly, to a light emitting device including a reflective layer formed on both sides of a light transmissive body.
Background
Light-Emitting diodes (LEDs) have the characteristics of low power consumption, long lifetime, small volume, fast response speed, and stable optical output. In recent years, light emitting diodes have been increasingly used as backlights in liquid crystal displays.
Disclosure of Invention
In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described below.
A light emitting device, comprising: a light emitting structure having a side surface; a reflective layer covers the side surfaces. The light-emitting device has a first light-emitting angle and a second light-emitting angle. The difference between the first light-emitting angle and the second light-emitting angle is larger than 15 degrees.
Drawings
FIG. 1A is a bottom view of a light emitting device in accordance with an embodiment of the present invention;
FIG. 1B is a cross-sectional view taken along line I-I of FIG. 1A;
FIG. 1C is a cross-sectional view taken along line II-II of FIG. 1A;
FIG. 1D is an enlarged view at A of FIG. 1B;
FIG. 1E is an enlarged view at B of FIG. 1C;
FIG. 1F is a schematic view of a measurement mode of the light emitting device;
FIGS. 2A-2D are cross-sectional views of a light-emitting device according to another embodiment of the present invention;
FIGS. 3A-3G are cross-sectional views illustrating a manufacturing process of a light emitting device according to an embodiment of the present invention;
FIGS. 4A to 4G are top views of FIGS. 3A to 3G, respectively;
FIGS. 5A-5C are cross-sectional views of a light emitting device in accordance with an embodiment of the present invention;
FIGS. 6A-6B are cross-sectional views illustrating the formation of a second reflective layer according to another embodiment of the present invention;
FIGS. 7A to 7G are cross-sectional views illustrating a manufacturing process of a light emitting device according to another embodiment of the present invention;
FIGS. 8A-8C are cross-sectional views of a light emitting device in accordance with an embodiment of the present invention;
FIGS. 9A to 9E are top views illustrating a manufacturing process of a light emitting device according to another embodiment of the present invention;
FIGS. 10A-10D are cross-sectional views of a light emitting device in accordance with an embodiment of the present invention;
FIG. 11A is a cross-sectional view of a step in the process flow of fabricating a light emitting device in one embodiment;
FIG. 11B is a top view of a step in the process flow of fabricating a light emitting device in one embodiment;
FIG. 11C is a cross-sectional view of a light emitting device in accordance with an embodiment of the present invention;
FIG. 12A is a top view of a light emitting device in accordance with an embodiment of the present invention;
FIG. 12B is a cross-sectional view taken along line I-I of FIG. 12A;
FIGS. 13A-13F are cross-sectional views illustrating a manufacturing process of a light emitting device according to an embodiment of the present invention;
FIGS. 14A to 14F are top views of FIGS. 13A to 13F, respectively;
15A-15F are cross-sectional views illustrating a manufacturing process of a light emitting device according to an embodiment of the present invention;
FIGS. 16A to 16F are top views of FIGS. 15A to 15F, respectively;
FIGS. 17A to 17F are sectional views showing a manufacturing process in which the upper surface of the light-transmitting body has a wavy shape;
fig. 18A to 18E are sectional views of the light-transmitting body having different shapes on the upper surface thereof, respectively;
FIG. 19 is a cross-sectional view of a light emitting device in accordance with one embodiment of the present invention;
fig. 19A to 19C are sectional views of light-emitting devices used in the simulation;
FIGS. 20A-20G are cross-sectional views illustrating a manufacturing process of a light emitting device according to an embodiment of the present invention;
FIGS. 21A to 21G are top views of FIGS. 20A to 20G, respectively;
FIG. 22A is a cross-sectional view of a light emitting device in accordance with one embodiment of the present invention;
FIG. 22B is a cross-sectional view of a light emitting device in accordance with one embodiment of the present invention;
FIG. 22C is a cross-sectional view of a light emitting device in accordance with one embodiment of the present invention;
FIGS. 23A-23F are cross-sectional views illustrating a manufacturing process of a light emitting device according to an embodiment of the present invention;
FIGS. 24A to 24F are top views of FIGS. 23A to 23F, respectively;
FIGS. 25A-25D are perspective views illustrating a manufacturing process of the light-emitting device of the present invention;
fig. 26A to 26C are sectional views of fig. 25B to 25D, respectively;
FIG. 27A is a cross-sectional view of a backlight unit of a side-lit LCD;
FIG. 27B is a perspective view of the light source and the light guide plate shown in FIG. 12A;
FIG. 28 is a cross-sectional view of a backlight unit of a side-view LCD;
fig. 29 is a cross-sectional view of a backlight unit of a side-view liquid crystal display.
Description of the symbols
100. 100', 100", 100'", 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100 light emitting devices
11. 11D, 11E, 11F light emitting structure
110 patterned substrate
1101 upper surface
1102 lower surface
1103 first side surface
1104 second side surface
1105 third side surface
1106 fourth side surface
1110 holes
111A, 111B light emitting body
1111 first type semiconductor layer
1112 active layer
1113 second-type semiconductor layer
1114 a first insulating layer
1115 second insulating layer
1116 conductive layer
1117 third insulating layer
1118 first electrode
1119 second electrode
1120 ohmic contact layer
1161 first area
1162 second area
1163 third area
112 groove
211 electrode layer
1124 upper surface
12 light transmitting body
121 upper surface
122 lower surface
123 first side surface
124 second side surface
125 third side surface
126 fourth side surface
13 wavelength conversion body
131 wavelength converting particles
14 first reflective layer
15A, 15B extension electrode
151 first end
152 second end
17. 17A, 17B, 17C second reflective layer
171. 171', 171", 171'", 171A, 171B, 171C outer surface
172. 172', 172", 172'", 172A, 172B, 172C inner surfaces
172A1 ramp
172A2 plane
173 upper surface
174 lower surface
21. 26 glue material
22. 27 carrier plate
23. 23A, 23B cutter
231 grooves
251 upper die
252 lower die
2521. 38 groove
37 reflection frame
371 penetration hole
901 luminous source
9011 support plate
902 light guide plate
903 diffusion plate
904 reflector
Detailed Description
The following embodiments will explain the concept of the present invention along with the accompanying drawings, in which like or similar parts are designated by the same reference numerals, and in which the shape, thickness or height of elements may be enlarged or reduced. The examples are given solely for the purpose of illustration and are not intended to limit the scope of the invention. It will be apparent that modifications and variations are possible without departing from the spirit and scope of the invention.
FIG. 1A is a bottom view of a light emitting device 100 according to an embodiment of the invention, wherein for clarity, FIG. 1A only shows a portion of the layers and each layer is illustrated in solid lines (however, conductive layer 1116 is illustrated in dashed lines for clarity) regardless of whether the material is non-transparent, or translucent. FIG. 1B is a cross-sectional view taken along line AI-I of FIG. 1. FIG. 1C is a cross-sectional view taken along line AII-II of FIG. 1. Fig. 1D is an enlarged view of fig. 1B at a. Fig. 1E is an enlarged view at B of fig. 1C. For simplicity, the light emitting structure 11 of fig. 1B and 1C is only shown in a square shape, and the detailed structure is described in fig. 1D and 1E.
Referring to fig. 1A, 1B, and 1D, the light emitting device 100 includes a light emitting structure 11, a transparent body 12, a wavelength converter 13, a first reflective layer 14, extension electrodes 15A and 15B, and a second reflective layer 17. The light emitting structure 11 includes a patterned substrate 110 and two light emitting bodies 111A and 111B. The patterned substrate 110 is substantially a rectangular parallelepiped, and includes an upper surface 1101, a lower surface 1102 opposite to the upper surface 1101, and four side surfaces (a first side surface 1103, a second side surface 1104, a third side surface 1105 and a fourth side surface 1106) connected between the upper surface 1101 and the lower surface 1102. The lower surface 1102 is a patterned surface having a regular or irregular arrangement of protrusions and recesses. The light-transmitting body 12 covers an upper surface 1101, four side surfaces 1103 to 1106, and a part of a lower surface 1102.
Referring to fig. 1D, in the present embodiment, the light emitting structure 11 includes a patterned substrate 110, two light emitting bodies 111A and 111B commonly formed on the patterned substrate 110, and a groove 112 formed between the two light emitting bodies 111A and 111B to physically separate the two light emitting bodies 111A and 111B from each other. Each of the light emitting bodies 111A, 111B includes a first type semiconductor layer 1111, an active layer 1112, and a second type semiconductor layer 1113. A first insulating layer 1114 is formed in the trench 112 and covers the first semiconductor layer 1111 of the light emitting bodies 111A, 111B to prevent unnecessary circuit paths (short circuits) between the adjacent light emitting bodies 111A, 111B. A second insulating layer 1115 is formed on the first insulating layer 1114 and exposes the second-type semiconductor layer 1113 of the light emitting bodies 111A and 111B. A conductive layer 1116 is formed on the second insulating layer 1115 and the second-type semiconductor layer 1113 exposing the light emitting bodies 111A and 111B. In addition, the second insulating layer 1115 covers the sidewalls of the first insulating layer 1114. The conductive layer 1116 covers a portion of a sidewall of the second insulating layer 1115 and extends to the first-type semiconductor layer 1113. A third insulating layer 1117 is formed on the conductive layer 1116 to cover the light emitting bodies 111A and 111B and expose a portion of the conductive layer 1116. A first electrode 1118 and a second electrode 1119 are electrically connected to the light emitting body 111A and the light emitting body 111B, respectively. The electrical connection between the light emitting bodies 111A, 111B will be described later. An ohmic contact layer 1120 may be selectively formed between the second-type semiconductor layer 1113 and the conductive layer 1116 to reduce the driving voltage of the light emitting device 100.
For clarity, conductive layer 1116 of FIG. 1A is shown in dashed lines. Referring to fig. 1A, 1D and 1E, the conductive layer 1116 includes a first region 1161, a second region 1162 (hatched regions in fig. 1A) and a third region 1163. The first region 1161 is formed only in the light emitting body 111A and is physically separated from the second region 1162. The second area 1162 surrounds the first area 1161. The second region 1162 is in contact with the first-type semiconductor layer 1111 of the light emitting body 111A, and further formed on the second insulating layer 1115 in the trench 112 and extended to the second-type semiconductor layer 1113 of the light emitting body 111B, whereby the conductive layer 1116 connects the light emitting body 111A and the light emitting body 111B in series (this connection is not shown in FIG. 1D due to the location of the cross-hatching).
Referring to fig. 1A, 1D and 1E, a plurality of holes 1110 are formed in the third insulating layer 1117, and the holes 1110 are formed only at the light emitting body 111A and not at the light emitting body 111B. The first electrode 1118 can extend into the hole 1110 and electrically connect to the first region 1161 of the conductive layer 1116 on the light emitting body 111A, so that the first electrode 1118 is electrically connected to the second type semiconductor layer 1113 of the light emitting body 111A. The third region 1163 of the conductive layer 1116 is formed only in the light emitting body 111B. The second electrode 1119 is directly in contact with the third region 1163 of the conductive layer 1116 exposed from the third insulating layer 1117. The third region 1163 of the conductive layer 1116 contacts the first-type semiconductor layer 1111 of the light emitting body 111B. In the present embodiment, for example, when the first electrode 1118 is electrically connected to the positive electrode of the external electrode and the second electrode 1119 is electrically connected to the negative electrode of the external electrode, a current sequentially flows through the first electrode 1118 in the hole 1110, the first region 1161 of the conductive layer 1116, the second type semiconductor layer 1113 of the light emitting body 111A, the active layer 1112 of the light emitting body 111A, the first type semiconductor layer 1111 of the light emitting body 111A, the second region 1162 of the conductive layer 1116, the second type semiconductor layer 1113 of the light emitting body 111B, the active layer 1112 of the light emitting body 111B, the first type semiconductor layer 1111 of the light emitting body 111B, the third region 1163 of the conductive layer 1116, and finally to the second electrode 1119, so that the light emitting body 111A and the light emitting body 111B are connected to each other in series. In addition, combining the above overall design, the fabrication process of forming the holes 1110 in the light emitting bodies 111B can be reduced and the conductive layer 1116 covering the sidewalls of the light emitting bodies 111A, 111B can increase the light intensity (lumens) of the light emitting device 100 and reduce the forward bias (Vf) of the light emitting device 100 as a whole.
In this embodiment, the material of the first electrode 1118, the second electrode 1119, and the conductive layer 1116 may be a metal, such as gold (Au), silver (Ag), copper (Cu), chromium (Cr), aluminum (Al), platinum (Pt), nickel (Ni), titanium (Ti), tin (Sn), or an alloy or a stacked combination thereof. The first insulating layer 1114 may be a single layer or a plurality of layers. When the first insulating layer 1114 is a single layer, the material may include an oxide, a nitride, or a polymer; the oxide may comprise alumina (Al)2O3) Silicon oxide (SiO)2) Titanium dioxide (TiO)2) Tantalum Pentoxide (Ta), Tantalum Pentoxide (Ta)2O5) Or aluminum oxide (AlO)x) (ii) a The nitride may comprise aluminum nitride (AlN), silicon nitride (SiN)x) (ii) a The polymer may comprise polyimide (polyimide) or benzocyclobutane (BCB). When the first insulating layer 1114 is a multilayer, the material may include aluminum oxide (Al)2O3) Silicon oxide (SiO)2) Titanium dioxide (TiO)2) Niobium pentoxide (Nb)2O5) And silicon nitride (SiN)x) To form a Distributed Bragg Reflector (Bragg Reflector). The materials of the second insulating layer 1115 and the third insulating layer 1117 can be selected with reference to the first insulating layer 1114.
Referring to fig. 1A and 1C, the light-transmitting body 12 substantially has a rectangular parallelepiped and covers the light-emitting structure 11, and thus in fig. 1A, the light-transmitting body 12 has a rectangular shape. The light-transmitting body 12 includes an upper surface 121, a lower surface 122 opposite to the upper surface 121, and four side surfaces (a first side surface 123, a second side surface 124, a third side surface 125, and a fourth side surface 126) connected between the upper surface 121 and the lower surface 122. In fig. 1A, the first side surface 123 is substantially parallel to the third side surface 125 and is a long side of the rectangular parallelepiped; the second side surface 124 and the fourth side surface 126 are parallel to each other and are short sides of a rectangular parallelepiped. The second reflective layer 17 covers the first side surface 123 and the third side surface 125, but does not cover the second side surface 124, the fourth side surface 126, the upper surface 121 and the lower surface 122, so the second reflective layer 17 covers the first side surface 1103 and the third side surface 1105 of the light emitting structure 11 and does not cover the second side surface 1104 and the fourth side surface 1106 of the light emitting structure 11.
Referring to fig. 1C, the second reflective layer 17 has an outer surface 171 and an inner surface 172, and the outer surface 171 is substantially a plane (straight line in fig. 1C) and perpendicular to the upper surface 121. The inner surface 172 has an arcuate shape. In detail, the distance (D1) between the inner surface 172 and the outer surface 171 is gradually decreased from the upper surface 121 to the lower surface 122 of the light-transmitting body 12, and the inner surface 172 extends to the first reflective layer 14 and is not connected to the outer surface 171. In addition, the extension electrode 15A and the second reflective layer 17 overlap each other in a Z direction.
The second reflective layer 17 reflects light emitted from the light-emitting structure 11 to exit the light-emitting device 100 toward the upper surface 121 and/or the side surfaces 124 and 126 of the light-transmissive body 12. Further, the second reflective layer 17 is a mixture including a matrix and a plurality of reflective particles doped in the matrix, so that the light emitted from the light emitting structure 11 is reflected by the second reflective layer 17 and the reflection pattern is diffuse reflection (diffuse reflection). The substrate is an insulating material and comprises a silicone-based substrate (silicone-based) or an epoxy-based substrate (epoxy-based); the reflective particles may comprise titanium dioxide, silicon dioxide, barium sulfate, or aluminum oxide. Since the reflectivity of the second reflective layer 17 for different wavelengths is dependent on its thickness, the thickness of the second reflective layer 17 (i.e., the maximum distance between the inner surface 172 and the outer surface 171) is between 50 μm and 160 μm (um). When the thickness of the second reflective layer 17 is less than 50 μm, the reflectivity for light with a peak value of 430-450 nm is less than 90%; the reflectivity of light with the wave peak value of 540-570 nm is less than 88%; and the reflectivity of light with the wave peak value of 620-670 nm is less than 80%. When the thickness of the second reflective layer 17 is about 160 μm, the reflectivity for light with peak values of 430-450 nm, 540-570 nm and 620-670 nm is greater than 95%. However, when the thickness of the second reflective layer 17 is larger than 160 μm, the thickness of the light-emitting device 100 in the Y direction and the manufacturing cost may be increased, which may limit the applicability (e.g., mobile phones, liquid crystal displays, wearable devices (watches, bracelets, necklaces, etc.)). In another embodiment, the thickness of the second reflective layer 17 may be greater than 160 μm, or between 50 μm and 1000 μm, depending on the application.
Referring to fig. 1B and 1D, the first reflective layer 14 is formed on the third insulating layer 1117 and has a first portion 141, a second portion 142, and a third portion 143. The extension electrodes 15A, 15B are formed on the first reflective layer 14. In detail, the first portion 141 of the first reflective layer 14 only covers a portion of the first electrode 1118 and has an arc-shaped cross section; the second portion 142 of the first reflective layer 14 is formed between the first electrode 1118 and the second electrode 1119 and covers a portion of the first electrode 1118 and a portion of the second electrode 1119; the third portion 143 of the first reflective layer 14 covers only a portion of the second electrode 1119. The extension electrode 15A covers only the first portion 141 and the second portion 142 of the first reflective layer 14, and the extension electrode 15B covers only the second portion 142 and the third portion 143 of the first reflective layer 14. The extension electrode 15A and the extension electrode 15B are in contact with and electrically connected to the first electrode 1118 and the second electrode 1119, respectively. The extension electrode 15A has a first end 151 coplanar with the second side surface 124; a second end 152 is located at the second portion 142 of the first reflective layer 14 and has an arc-shaped cross section. The extension electrode 15B has a similar structure to the extension electrode 15A. In fig. 1D, the second portion 142 of the first reflective layer 14 directly contacts the third insulating layer 1117 and completely fills the space between the first electrode 1118 and the second electrode 1119, and no transparent body 12 is formed between the first reflective layer 14 and the third insulating layer 1117. In another embodiment, the light-transmissive body 12 may be formed between the first reflective layer 14 and the third insulating layer 1117 during the manufacturing process.
Referring to fig. 1B and 1C, the wavelength converter 13 is formed in the light-transmissive body 12. In the present embodiment, the wavelength converter 13 includes a plurality of wavelength converting particles 131 dispersed in a matrix. The wavelength converting particles 131 cover the upper surface 1101, the first side surface 1103, the second side surface 1104, a portion of the third side surface 1105, and a portion of the fourth side surface 1106 of the patterned substrate 110. Portions of the third side surface 1105 and the fourth side surface 1106 are not covered by the wavelength converting particles 131. Optionally, the wavelength converter 13 and/or the light-transmitting body 12 may further include a diffusing powder. The matrix comprises Epoxy (Epoxy), Silicone (Silicone), Polyimide (PI), benzocyclobutene (BCB), Perfluorocyclobutane (PFCB), Su8, Acrylic (Acrylic Resin), Polymethylmethacrylate (PMMA), polyethylene terephthalate (PET), Polycarbonate (PC), or Polyetherimide (polyethylimide). The light-transmissive body 12 may include Epoxy (Epoxy), Silicone (Silicone), Polyimide (PI), benzocyclobutene (BCB), Perfluorocyclobutane (PFCB), Su8, Acrylic (Acrylic Resin), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), Polycarbonate (PC), or Polyetherimide (Polyetherimide). When the material of the substrate of the wavelength converting body 13 is the same as that of the light transmitting body 12, the interface therebetween is not blurred under electron microscope irradiation, or the interface is not seen to exist between the substrate of the wavelength converting body 13 and the light transmitting body 12, that is, the wavelength converting particles 131 are dispersed in the light transmitting body 12.
The wavelength converting particles 131 have a particle size of 5 μm to 100 μm and may include one or more kinds of inorganic phosphors (phosphors), organic molecular fluorescent pigments (organic fluorescent pigments), semiconductor materials (semiconductor), or a combination thereof. The inorganic phosphor material includes, but is not limited to, yellow-green phosphor or red phosphor. The yellow-green phosphor is composed of, for example, aluminum oxide (YAG or TAG), silicate, vanadate, alkaline earth metal selenide, or metal nitride. Composition of red phosphor such as fluoride (K)2TiF6:Mn4+、K2SiF6:Mn4+) Silicates, vanadates, alkaline earth metal sulfides (CaS), metal oxynitrides, or mixtures of the tungsten molybdate family. The wavelength conversion particles are present in the matrix in a weight percentage (w/w) of between 50 and 70%. The semiconductor material comprises a nano-sized crystalline (nano-crystalline) semiconductor material, such as a quantum-dot (quantum-dot) light emitting material. The quantum dot luminescent material is selected from zinc sulfide (ZnS) and selenizationZinc (ZnSe), zinc telluride (ZnTe), zinc oxide (ZnO), cadmium sulfide (CdS), cadmium selenide (CdSe), cadmium telluride (CdTe), gallium nitride (GaN), gallium phosphide (GaP), gallium selenide (GaSe), gallium antimonide (GaSb), gallium arsenide (GaAs), aluminum nitride (AlN), aluminum phosphide (AlP), aluminum arsenide (AlAs), indium phosphide (InP), indium arsenide (InAs), tellurium (Te), lead sulfide (PbS), indium antimonide (InSb), lead telluride (PbTe), lead selenide (PbSe), antimony telluride (SbTe), zinc cadmium selenium sulfide (ZnCdSeS), copper indium sulfide (CuInS), cesium lead chloride (CsPbCl)3) Cesium lead bromide (CsPbBr)3) And cesium lead iodide (CsPbI)3) The group consisting of.
The diffusion powder contains titanium dioxide, zirconium oxide, zinc oxide, or aluminum oxide, and can scatter light emitted from the light emitting structure 11. The weight percentage concentration (w/w) of the diffusion powder in the matrix is 0.1-0.5% and the particle size is 10 nm-100 nm or 10-50 μm. In one embodiment, the weight percent powder concentration of the diffusing powder (or wavelength converting particles) in the matrix can be measured by a thermogravimetric analyzer (TGA). Briefly, during heating, the matrix is removed (evaporated or thermally cracked) as a result of the temperature gradually rising and after reaching a certain temperature, leaving behind diffusion powder (or wavelength conversion particles). By measuring the change in weight, the respective weights of the matrix and the diffusion powder (or wavelength conversion particles), and the weight percentage concentration of the diffusion powder in the matrix can be obtained. Alternatively, the total weight of the matrix and the diffusion powder (or the wavelength conversion particles) may be measured, the colloid may be removed by using a solvent, and the weight of the diffusion powder (or the wavelength conversion particles) may be measured, so as to obtain the weight percentage concentration of the diffusion powder (or the wavelength conversion particles) in the matrix.
The wavelength converting particles 131 may absorb the first light emitted from the light emitting structure 11 and convert the first light into second light having a different spectrum from the first light. The first light, if mixed with the second light, generates a third light. In the embodiment, the third light has a color point coordinate (x, y) in the CIE1931 chromaticity diagram, wherein x is greater than or equal to 0.27 and less than or equal to 0.285; y is more than or equal to 0.23 and less than or equal to 0.26. In another embodiment, the first light and the second light are mixed to generate a third light, such as white light. The light emitting device can have a white light relative color temperature (CCT) of 2200K to 6500K (e.g., 2200K, 2400K, 2700K, 3000K, 5700K, 6500K) in a thermal steady state according to the weight percentage concentration and the type of the wavelength conversion particles, a color point coordinate (x, y) falling within a range of seven MacAdam ellipsoids (MacAdam ellipsose) in a CIE1931 chromaticity diagram, and a Color Rendering Index (CRI) of more than 80 or more than 90. In another embodiment, the first light and the second light are mixed to generate purple light, amber light, green light, yellow light or other non-white light.
As shown in fig. 1A to 1C, the first side surface 123 and the third side surface 125 of the light-transmitting body 12 are covered by the second reflective layer 17, and the lower surface 122 is covered by the first reflective layer 14 and the extension electrodes 15A and 15B, so that the light-emitting device 100 substantially has only three light-emitting surfaces. In other words, the light emitted by the light emitting structure 11 directly exits the light emitting device 100 through the upper surface 121, the second side surface 124 and the fourth side surface 126 of the light transmissive body 12. The light-emitting angle (defined later) of the light-emitting structure 11 is about 140 degrees, so that more than 50% of the light is emitted from the upper surface 1101 (or the upper surface 121 of the light-transmissive body 12), and the upper surface 1101 of the light-emitting structure 11 is defined as the main light-emitting surface of the light-emitting structure 11. The light-emitting structure 11 emits light outward (away from the light-emitting device 100) from the Z-axis direction in the same direction as the light-emitting device 100. Therefore, the main light emitting surface of the light emitting structure 11 is substantially parallel to the light emitting surface of the light emitting device 100.
Fig. 2A to fig. 2C are cross-sectional views of a light emitting device 100', 100", 100'" according to another embodiment of the present invention. The light emitting devices 100', 100", 100'" have a similar structure as the light emitting device 100. Wherein elements or devices corresponding to the same reference signs or signs have similar or identical elements or devices. Like fig. 1C, fig. 2A to 2C are sectional views taken along line II-II in fig. 1A. However, the corresponding bottom view and the cross-sectional view along the line I-I can refer to FIG. 1A, FIG. 1B and FIG. 1D.
Referring to fig. 2A, the second reflective layer 17' has an outer surface 171' and an inner surface 172 '. The outer surface 171' is substantially planar (straight in fig. 2A) and perpendicular to the upper surface 121. The inner surface 172' has an arcuate shape. In detail, the distance (D1) between the inner surface 172 'and the outer surface 171' is gradually decreased from the upper surface 121 to the lower surface 122 of the light-transmitting body 12, and the inner surface 172 'is connected to the outer surface 171'.
Referring to fig. 2B, the second reflective layer 17 "has an outer surface 171" and an inner surface 172 ". The outer surface 171 "is substantially planar (straight in fig. 2B) and perpendicular to the upper surface 121. The inner surface 172 "has an arcuate shape. In detail, the distance (D1) between the inner surface 172 ″ and the outer surface 171 ″ is gradually increased from the upper surface 121 to the lower surface 122 of the light-transmitting body 12.
Referring to fig. 2C, the second reflective layer 17' "has an outer surface 171'" and an inner surface 172' ". The outer surface 171 '"and an inner surface 172'" are both substantially planar (straight in fig. 2C) and perpendicular to the upper surface 121.
Fig. 2D is a cross-sectional view of a light emitting device 200 according to another embodiment of the invention. The light emitting device 200 has a similar structure to the light emitting device 100. Wherein elements or devices corresponding to the same reference signs or signs have similar or identical elements or devices. In this embodiment, the second reflective layer 27 comprises a metal, such as: gold (Au), silver (Ag), copper (Cu), chromium (Cr), aluminum (Al), platinum (Pt), nickel (Ni), or rhodium (Rh), so that the light emitted from the light-emitting structure 11 is reflected by the second reflective layer 27 in a specular reflection (specular reflection). In addition, the second reflective layer 27 is metal and the thickness of the second reflective layer 27 is
The cross-sectional shape of the second reflective layer depends on the shape and size of the cutting tool used in the fabrication process. When the dicing blade has an arc-shaped cross section, the second reflective layer has an inner surface with an arc-shaped cross section (refer to fig. 1C, fig. 2A, and fig. 2B); when the dicing blade has a straight section, the second reflective layer has an inner surface of a straight section (refer to fig. 2C, 2D). Of course, the shape and size of the cutting blade may also determine the curvature of the arc. In addition, the shape of the inner surface of the second reflective layer may affect the brightness of the light emitting device. In general, the second insulating layer having an inner surface with an arc-shaped cross section allows more light to leave the light emitting device than a straight cross section. Furthermore, the light emitting device of FIG. 2B has a larger light emitting brightness (e.g., luminous flux (lumen value)) than the light emitting device of FIG. 2A or FIG. 1C.
Referring to fig. 1A, since the second reflective layer 17 only covers the first side surface 123 and the third side surface 125, light emitted by the light emitting structure 11 and directed to the first side surface 123 and the third side surface 125 is reflected by the second reflective layer 17, however, the light directed to the second side surface 124 and the fourth side surface 126 directly exits the light emitting device 100. Therefore, the light emitting device 100 has different light emitting angles in different directions. Further, fig. 1F is a schematic diagram illustrating a measurement method of the light emitting device 100. When the light emitting device 100 emits light, the light emission intensity of each point on the circle P1 or the circle P2 can be measured by a light distribution curve meter (Goniophotometer; ama photoelectric, model LID-100 CS). The P1 circle or the P2 circle is a virtual circle defined for measurement. The angle and the luminous intensity corresponding to each point on the P1 circle are measured and recorded to obtain a first light distribution curve graph and derive a first luminous angle. Similarly, the content of taiwan application 105114875 can be referred to for a detailed description of obtaining a first light distribution curve graph and deriving a first light emission angle P1 circle and a first light emission angle P2 circle by measuring and recording the angle and the light emission intensity corresponding to each point on the P2 circle. The first light emitting angle may be greater than the second light emitting angle. In one embodiment, the first light-emitting angle in the long side direction (X direction) is between 130 and 150 degrees, and the second light-emitting angle in the short side direction (Y direction) is between 100 and 125 degrees. Or the difference range between the first light-emitting angle and the second light-emitting angle is larger than 15 degrees and between 15 degrees and 40 degrees. The light emission angle described herein is defined as an angle range included when the luminance is 50% of the maximum luminance, which is the light emission angle. For a detailed description of the light emitting angle, reference may be made to taiwan application 104103105.
The two light emitting bodies in fig. 1A are connected in series with each other. In other embodiments, the light emitting structure 11 may include one light emitting body or three or more light emitting bodies connected in series, in parallel, in a series-parallel mixed connection, or in a bridge connection. When the light-emitting structure 11 includes a plurality of light-emitting bodies, the plurality of light-emitting bodies may be formed on a substrate, or each of the plurality of light-emitting bodies has a substrate and is fixed on a carrier, or a portion of the light-emitting bodies are formed on a substrate, and another portion of the light-emitting bodies has a substrate and are fixed on a carrier. In addition, the two light-emitting bodies in the embodiment are electrically connected with each other in a flip-chip structure through a conductive layer, however, the two light-emitting bodies can also be in a horizontal structure and are electrically connected with each other in a wire bonding manner.
When the light-emitting body is a heterostructure, the first type semiconductor layer and the second type semiconductor layer are, for example, cladding layers (cladding layers) and/or confinement layers (confining layers), and can provide electrons and holes respectively and have a band gap larger than that of the active layer, thereby increasing the probability of the electrons and holes combining in the active layer to emit light. The first-type semiconductor layer, the active layer, and the second-type semiconductor layer may comprise a III-V semiconductor material, such as AlxInyGa(1-x-y)N or AlxInyGa(1-x-y)P, wherein x is more than or equal to 0, and y is less than or equal to 1; (x + y) is less than or equal to 1. According to the material of the active layer, the luminescent main body can emit red light with a peak value (peak wavelength) or a dominant wavelength (dominant wavelength) between 610nm and 650nm, green light with a peak value or a dominant wavelength between 530nm and 570nm, blue light with a peak value or a dominant wavelength between 450nm and 490nm, purple light with a peak value or a dominant wavelength between 400nm and 440nm, or ultraviolet light with a peak value between 200nm and 400 nm.
Fig. 3A to fig. 3G are cross-sectional views illustrating a manufacturing process of a light emitting device according to an embodiment of the invention, and fig. 4A to fig. 4G are top views of fig. 3A to fig. 3G, respectively. Fig. 3A to 3G are cross-sectional views taken along line W-W in fig. 4A to 4G, respectively. For the sake of simplicity, the light emitting structure 11 described later is only illustrated as a rectangle in the drawings, however, in the top view, other shapes, such as a square, a trapezoid, a parallelogram, a rhombus, a triangle, a pentagon, a hexagon, and a circle, can also be applied to the embodiments of the present invention. Moreover, for clarity, each structure is drawn as a solid line whether it is non-transparent, or translucent.
Referring to fig. 3A and fig. 4A, a carrier 22, a glue 21 attached on the carrier 22, and a plurality of light emitting structures 11 disposed on the glue 21 are provided. In the embodiment, the light emitting structure 11 is attached on the adhesive 21 by the sides of the first electrode 1118 and the second electrode 1119. The number and arrangement of the light emitting structures 11 in fig. 4A are merely exemplary and not limited thereto.
Referring to fig. 3B and 4B, a transparent body including a plurality of wavelength conversion particles 131 completely covers the light emitting structure 11. The transparent body may be formed on the light emitting structure 11 by dispensing (spraying), coating (coating), spraying (painting), printing (screen printing), and the like. The transparent body is then cured to form the light transmissive body 12. If the transparent body is formed on the light emitting structure 11 by spraying or dispensing, the transparent body may have different heights (Z direction) at different positions in the whole area. After hardening, the transparent body is cured into the light-transmitting body 12, and the light-transmitting body 12 has different heights at different positions. Therefore, a physical removal step may be performed to planarize the light transmissive body 12 such that the top surface 121 of the light transmissive body 12 becomes substantially planar. The definitions of "physical removal step" and "substantially flat" are detailed below.
Furthermore, in the present embodiment, due to gravity, the wavelength conversion particles 131 are naturally deposited during the curing process, so that most of the wavelength conversion particles 131 contact the light emitting structure 11, and only a portion of the wavelength conversion particles 131 are attached to the side surface of the light emitting structure 11 (refer to the related description of fig. 1B and 1C for details). In other embodiments, the curing temperature and time can be controlled to determine the distribution of the wavelength conversion particles 131 in the transparent body 12. For example, when the wavelength conversion particles 131 have not been deposited to the bottom and the transparent body is completely cured, the wavelength conversion particles 131 are suspended in the transparent body 12 and are not in contact with the light emitting structure 11. Alternatively, the addition of an anti-settling agent (e.g., silica) to the transparent body can also prevent the wavelength converting particles 131 from settling to the bottom during curing, allowing the wavelength converting particles 131 to be uniformly dispersed in the light transmitting body 12.
In another embodiment, the transparent body containing the plurality of wavelength conversion particles 131 can be formed into a wavelength conversion sheet and then attached to the light emitting structure 11. The bonding is performed by bonding an upper mold (not shown) and a lower mold (not shown), and at the same time, the wavelength conversion sheet is heated and pressurized to soften the wavelength conversion sheet so that it can be tightly bonded to the light emitting structure 11. In addition, when the upper mold and the lower mold are very close to each other but the wavelength conversion sheet is not yet in contact with the light emitting structure 11, air is pumped, so that air bubbles between the wavelength conversion sheet and the light emitting structure 11 can be reduced, and the bonding force between the wavelength conversion sheet and the light emitting structure 11 is improved.
Referring to fig. 3C, 3D, 4C and 4D, a cutting blade 23 is provided and a cutting step is performed along the cutting line L in the X direction to form a plurality of grooves 231 in the light-transmitting body 12. The shape of the groove 231 corresponds to the shape of the cutting blade 23. For example, in the present embodiment, the cutting blade 23 has an arc-shaped cross-section, and thus the groove 231 also has an arc-shaped cross-section. In addition, the light-transmitting body 12 also has an arc-shaped cross section, and the arc-shaped cross section is closer to the lower surface 122 and surrounds the light-emitting structure 11. Further, the distance between the arc-shaped cross section and the light emitting structure 11 is smaller along the Z direction.
Referring to fig. 3E and 4E, a plurality of reflective particles (not shown) are mixed into a matrix to form a glue layer in an uncured state (the color of the glue layer may depend on the mixed reflective particles, and the common color is white). Then, the light-transmitting body 12 and the groove 231 are covered by a glue layer (preferably, the groove 231 is completely covered by the glue layer or only a small part of the area is not covered or bubbles remain); the glue layer is completely cured, thereby forming the second reflective layer 17. The height of the second reflective layer 17 is greater than the height of the light transmissive body 12. The second reflective layer 17 can be formed by dispensing (spraying), coating (coating), spraying (dispensing), printing (screen printing), and the like. Similarly, the second reflective layer 17 is also a preformed reflective sheet, which is attached to the transparent body 12. The description of fitting may refer to the preceding related paragraphs.
Referring to fig. 3F and 4F, a physical removal step (grinding or cutting) is used to remove a portion of the second reflective layer 17 to expose the light-transmissive body 12. In this embodiment, since the glue layer is formed by spraying or dispensing, the glue layer has different heights (Z direction) at different positions in the whole area (see fig. 3E). After hardening, the glue layer is cured to a second reflective layer 17, and the second reflective layer 17 also has different heights at different positions. In the physical removing step, a portion of the second reflective layer 17 is removed until the light-transmissive body 12 is exposed. Further, the removing step can be continued, so that the second reflective layer 17 and the transparent body 12 are removed at the same time. Therefore, the height of the light-transmitting body 12 can be reduced by using the manufacturing process. The height of the light-transmissive body 12 in fig. 3F may be equal to or less than the height of the light-transmissive body 12 of fig. 3E. In addition, the second reflective layer 17 has an upper surface 173 substantially coplanar with the upper surface 121 of the light transmissive body 12 and the upper surfaces 121 and 173 become substantially flat.
"substantially flat" is defined herein as viewing the light emitting device 100 through an electronic microscope at a magnification of 60-100 times, which is the case if the upper surfaces 121, 173 are substantially flat without severe undulations. However, when the light emitting device 100 is analyzed by an electron microscope at a magnification of more than 400 times, or measured by an alpha step film thickness measuring instrument (AFM) or an Atomic Force Microscope (AFM), the transparent body 12 and the second reflective layer 17 may have a rough upper surface 121, 173. In addition, in the present embodiment, the transparent body 12 is a silica gel having a hardness (Shore D) of 30 to 90, and the substrate of the second reflective layer 17 is a silica gel having a hardness (Shore D) of 10 to 70. The difference between the hardness of the transparent body 12 and the hardness of the matrix of the second reflective layer 17 is less than 30, so that after the physical removal step, the maximum roughness difference (Ra1) of the upper surface 121 of the transparent body 12 can be slightly larger than, equal to, or slightly smaller than the maximum roughness difference (Ra2) of the upper surface 173 of the second reflective layer 17. Measuring the upper surface 121 of the optically transparent body 12 by an alpha step film thickness measuring instrument, the difference (defined as the maximum roughness difference) between the highest point and the lowest point in the upper surface 121 of the optically transparent body 12 in a measurement length of 0.5mm being Ra 1; similarly, when the upper surface 173 of the second reflective layer 17 is measured, the difference between the highest point and the lowest point in the upper surface of the second reflective layer 17 in a measurement length of 50 μm is Ra 2; ra1 is more than or equal to 2 mu m and less than or equal to 15 mu m; ra2 is more than or equal to 2 mu m and less than or equal to 15 mu m; the absolute Ra1-Ra2 is more than or equal to 0 and less than or equal to 13 mu m.
The physical removal step is performed using a mechanical cutter. The material of the mechanical cutter may comprise high carbon steel, diamond, ceramic, or boron oxide. During the removal process, only water (without adding a slurry or chemical solution) may be added to lower the temperature between the cutter and the second reflective layer 17, which is increased by friction, and thereby clean the removed second reflective layer 17 and the removed light-transmissive body 12. Furthermore, if the hardness of the selected cutter is greater than that of the second reflective layer 17 and the transparent body 12, a plurality of scratches (not shown) are formed on the reflective insulating layer 12 and the transparent body 12, which can be observed by an optical microscope. However, in one embodiment, by adjusting the cutting parameters (e.g., cutting speed or material of the cutter), the scratches may not be observed through the optical microscope.
Referring to fig. 3G, 4G, and 5A to 5C, a dicing process is performed along dicing lines L (X and Y directions) to form a plurality of light emitting devices 300 independent of each other. Then, the adhesive material 21 is heated or irradiated with UV light to separate the light emitting structure 11 and the light transmitting body 12 from the adhesive material 21. Optionally, the first reflective layer 14 and the extension electrodes 15A and 15B may be further formed, and the detailed description thereof may refer to other related paragraphs.
Referring to fig. 3C and 4C, the relative positions of the light-transmitting body 12 and the light-emitting structure 11, that is, the distance between the first side surface 1103 and the first side surface 123 and the distance between the third side surface 1105 and the third side surface 125, can be changed by the difference of the cutting positions (see fig. 1A). Next, referring to fig. 3F and fig. 4F, the second reflective layer 17 is filled in the trench 231 and covers the side surface of the light-transmitting body 12. When the light emitted from the light emitting structure 11 is directed to the second reflective layer 17, the light is reflected and/or refracted at the interface between the transparent body 12 and the second reflective layer 17 (e.g., the first side surface 123 of the transparent body 12 and the inner surface 172 of the second reflective layer 17, as shown in fig. 1C) or in the second reflective layer 17. In summary, the manufacturing process of fig. 3C can be controlled to achieve a predetermined far field (far field) light pattern and a predetermined light emitting brightness (e.g., luminous flux (lumen value)) of the light emitting device.
Fig. 6A to 6B are cross-sectional views illustrating the formation of the second reflective layer 17 according to another embodiment of the present invention. After the cutting step is completed (as shown in fig. 3D), an upper mold 251 and a lower mold 252 are provided, the carrier 22 is fixed to the upper mold 251, and an uncured adhesive layer (the adhesive layer includes a matrix and reflective particles, the color of the adhesive layer may depend on the mixed reflective particles, and the common color is white) is filled in the groove 2521 of the lower mold 252. The upper and lower molds are brought close to each other to perform a compression molding step (compression molding), whereby the glue layer covers the light-transmissive body 12 and completely fills the groove 231. The glue layer is completely cured through a heat treatment process, thereby forming the second reflective layer 17. Since the second reflective layer 17 is formed by a mold in this embodiment, the second reflective layer 17 on the transparent body 12 has the same height at different positions. Next, the following operations can be referred to the descriptions of FIG. 3F to FIG. 3G.
Fig. 7A to 7G are cross-sectional views illustrating a manufacturing process of a light emitting device 400 according to another embodiment of the invention. The related upper views can refer to fig. 4A to 4G.
Referring to fig. 7A, a carrier 22, a plastic material 21 attached on the carrier 22, and a plurality of light emitting structures 11 disposed on the plastic material 21 are provided. In this embodiment, the light emitting structure 11 is attached on the adhesive 21 by the side of the electrodes 1118 and 1119. Carrier plate 22 is fixed to upper mold 251, and light-emitting structure 11 faces lower mold 252 from substrate 110 side. A transparent body containing a plurality of wavelength conversion particles 131 is filled in the groove 2521 of the lower mold 252. Next, a compression molding step (compression molding) is performed, so that the transparent body can completely cover the light emitting structure 11. Due to the influence of gravity, the wavelength conversion particles 131 settle at the bottom of the lower mold 252 during the curing of the transparent body, and thus, when the curing is completed to form the light-transmitting body 12, the wavelength conversion particles 131 are concentrated on the upper surface 121 of the light-transmitting body 12. In other embodiments, the curing time and curing temperature may be controlled such that the transparent body is completely cured to form the light-transmitting body 12 when the wavelength conversion particles 131 have not been deposited to the bottom of the lower mold 252. Alternatively, an anti-settling agent may be added to the transparent body to prevent the precipitation of the wavelength converting particles 131 during the curing process.
Referring to fig. 7B to 7D, a glue 26 is provided to be attached to the carrier 27. After the structure of fig. 7B is attached to the adhesive 26 through the transparent body 12, the adhesive 21 is heated or the adhesive 21 is irradiated with UV light, so that the light-emitting structure 11 and the transparent body 12 are separated from the adhesive 21 (the adhesive 21 and the carrier 22 are not shown in fig. 7C), and the electrodes 1118 and 1119 are exposed (the electrode 1119 is not shown in the figure due to the view). An electrode layer 211 is formed over the electrodes 1118 and 1119. The electrode layer 212 may be formed on the electrodes 1118 and 1119 of a single light emitting structure 11, respectively. Alternatively, the electrode layer 211 is formed on the electrode 1118 of the light emitting structure and the electrode 1119 of the adjacent light emitting structure, whereby the adjacent light emitting structures are connected in series with each other (not shown). Further, a cutting blade 23 is provided and performs a cutting operation along the cutting line L to form a plurality of grooves 231 in the light-transmitting body 12. The shape of the groove 231 corresponds to the shape of the cutting blade 23. For example, in the present embodiment, the cutting blade 23 has an arc-shaped cross-section, and thus the groove 231 also has an arc-shaped cross-section.
Referring to fig. 7E and 7F, similarly, the carrier 27 is fixed to the upper mold 251 and the recess 2521 of the lower mold 252 is filled with an uncured adhesive layer. A die-casting step is performed, so that the uncured glue layer covers the light-transmissive body 12 and the electrode layer 211 and completely fills the trench 231. Thereafter, the glue layer is completely cured through a heat treatment process, thereby forming the second reflective layer 17. Since the second reflective layer 17 is formed by a mold in this embodiment, the second reflective layer 17 on the electrode layer 211 has the same height at different positions. In addition, the height of the second reflective layer 17 is greater than the height of the light transmissive body 12.
Referring to fig. 7G, a physical removal step is used to remove a portion of the second reflective layer 17 to expose the electrode layer 211. Further, the removing step may be continued, so that the second reflective layer 17 and the electrode layer 211 are removed at the same time. Therefore, the height of the electrode layer 211 can be reduced by the manufacturing process. The height of the electrode layer 211 in fig. 7G may be equal to or less than the height of the electrode layer 211 in fig. 7F. The second reflective layer 17 has an upper surface 173 substantially coplanar with the upper surface 2111 of the electrode layer 211. In the embodiment, after the physical removing step, the maximum roughness difference (Ra3) of the upper surface 2111 of the electrode layer 211 may be slightly larger than, equal to, or slightly smaller than the maximum roughness difference (Ra4) of the upper surface 173 of the second reflective layer 17. Measuring the upper surface 2211 of the electrode layer 211 by an alpha step film thickness measuring instrument, wherein the difference (defined as the maximum roughness difference) between the highest point and the lowest point in the upper surface 1124 of the electrode layer 211 in a measurement length of 50 μm is Ra 3; similarly, when the upper surface 173 of the second reflective layer 17 is measured, the difference between the highest point and the lowest point in the upper surface of the second reflective layer 17 in a measurement length of 50 μm is Ra 4; ra3 is more than or equal to 2 mu m and less than or equal to 15 mu m; ra4 is more than or equal to 2 mu m and less than or equal to 15 mu m; the absolute Ra4-Ra3 is more than or equal to 0 and less than or equal to 13 mu m.
Referring to fig. 7G, a cutting step is performed along a cutting line L to form a plurality of light emitting devices 400 independent of each other as in fig. 8A to 8C. The adhesive 26 is heated or irradiated with UV light to separate the light emitting structure 11 and the transparent body 12 from the adhesive 26. Unlike the light emitting structure 300 of fig. 5A to 5C, the light emitting structure 400 of fig. 8A to 8C has an arc-shaped cross section of the light transmissive body 12 not surrounding the light emitting structure 11 and close to the upper surface 121 of the light transmissive body 12.
The glue materials 21 and 26 and the carrier plates 22 and 27 are used to temporarily fix the light emitting structure or the light emitting device during the manufacturing process. The glue materials 21, 26 include blue film, heat sink/glue, photolytic film (UV release tape), or polyethylene terephthalate (PET). The carrier plates 22, 27 comprise glass or sapphire for supporting the glue materials 21, 26.
Fig. 9A to 9E are top views illustrating a manufacturing process of a light emitting device 500 according to another embodiment of the present invention. The relevant cross-sectional views may refer to other paragraphs.
Referring to fig. 9A and 9B, a cutting blade (not shown) performs a cutting step along cutting lines L in the X direction and the Y direction to form a plurality of grooves 231 in the light-transmissive body 12.
Referring to fig. 9C, a second reflective layer 17 is formed to cover the transparent body 12 and completely fill the trench 231. The second reflective layer 17 can be formed in the manner described in the above related paragraphs.
Referring to fig. 9D, a physical removal step is used to remove a portion of the second reflective layer 17 to expose the light-transmissive body 12. Other related descriptions may refer to the description of fig. 4F and will not be written herein.
Referring to fig. 9E, a cutting process is performed along cutting lines L (X and Y directions) to form a plurality of light emitting devices 500 independent of each other, as shown in fig. 10A to 10D. Referring to fig. 10A and 10B, the second reflective layer 17 covers four side surfaces of the light transmissive body 12, and when the lower surface 122 is also covered by the first reflective layer 14 and the extension electrodes 15A and 15B, the light emitting device 500 substantially has only one light emitting surface. Referring to fig. 10C and 10D, the second reflective layer 17 covers three side surfaces of the light transmissive body 12, and when the lower surface 122 is also covered by the first reflective layer 14 and the extension electrodes 15A and 15B, the light emitting device 500 substantially has only two light emitting surfaces. Similarly, different cutting positions, in addition to changing the relative positions of the light-transmitting body 12 and the light-emitting structure 11, different forms of light-emitting devices can be formed to achieve a predetermined far-field light pattern and light-emitting brightness (e.g., luminous flux (lumen value)) to meet the requirements of different applications.
Similarly, as shown in fig. 11A and 11B, in the structure of fig. 4G, a light emitting device 600 (as shown in fig. 11C) in which the second reflective layer 17 covers only one side surface of the light transmissive body 12 can be obtained by cutting along the cutting line (L) at the interface between the light transmissive glue 12 and the second reflective layer 17. In an embodiment, the second reflective layer 17 covers one side surface of the light transmissive body 12, and when the lower surface 122 is also covered by the first reflective layer 14 and the extension electrodes 15A and 15B, the light emitting device 600 substantially has only four light emitting surfaces. Compared to the light emitting device 100 of fig. 1A, the light emitting device 600 has a larger light emitting brightness (e.g., luminous flux (lumen value)).
Fig. 12A is a top view of a light emitting device 700 according to an embodiment of the invention, where not all elements are shown for clarity, and each layer is shown in solid lines regardless of whether the material is non-transparent, or translucent. Fig. 12B is a sectional view taken along the line AI-I in fig. 12. For simplicity, the light emitting structure 11 of fig. 12A and 12B is only illustrated as a rectangle, however, in the top view, other shapes, such as a square, a trapezoid, a parallelogram, a rhombus, a triangle, a pentagon, a hexagon, and a circle, can also be applied to the embodiments of the present invention. Fig. 12A and 12B are a top view and a sectional view in one direction only. Other relevant views and the structure of the light emitting structure 11 can refer to the corresponding paragraphs and drawings in this specification.
Referring to fig. 12A and 12B, the light emitting device 700 includes a light emitting structure 11, a wavelength converter 13, a transparent body 12, a first reflective layer 14, an extension electrode 15A, and a second reflective layer 17. The light emitting structure 11 includes a top surface 1101, a bottom surface 1102 opposite to the top surface 1101, and four side surfaces (a first side surface 1103, a second side surface 1104, a third side surface 1105 and a fourth side surface 1106) connected between the top surface 1101 and the bottom surface 1102. The wavelength converter 13 covers an upper surface 1101, four side surfaces 1103 to 1106, and a part of a lower surface 1102. Similarly, the light-transmitting body 12 covers the wavelength converting body, i.e., the light-transmitting body 12 covers the upper surface and four side surfaces of the wavelength converting body 13. The light-transmitting body 12 includes an upper surface 121, a lower surface 122 opposite to the upper surface 121, and four side surfaces (a first side surface 123, a second side surface 124, a third side surface 125, and a fourth side surface 126) connected between the upper surface 121 and the lower surface 122. The second reflective layer 17 covers the upper surface 121, the first side surface 123, the second side surface 124, and the fourth side surface 126, but does not cover the third side surface 125 and the lower surface 122. In other words, the second reflective layer 17 covers the first side surface 1103, the second side surface 1104, and the fourth side surface 1106 of the light emitting structure 11, but does not cover the third side surface 1105.
Referring to fig. 12A and 12B, the light-emitting angle of the light-emitting structure 11 is about 140 degrees, so that more than 50% of the light is emitted from the upper surface 1101, and the upper surface 1101 of the light-emitting structure 11 is defined as the main light-emitting surface of the light-emitting structure 11. Since the upper surface 1101 and three side surfaces (1103, 1104, 1106) of the light emitting structure 11 are covered by the second reflective layer 17, and the lower surface 1102 is covered by the first reflective layer 14, the light emitted by the light emitting structure 11 is reflected by the second reflective layer 17 or/and the first reflective layer 14 and exits the light emitting device 700 through the third side surface 1105 and the third side surface 125 of the light transmissive body 12. In other words, the light emitting directions of the light emitting structure 11 and the light emitting device 700 are different, most of the light emitting structure 11 is emitted outward from the Z-axis direction (but not away from the light emitting device 700), and most of the light emitting device 700 is emitted outward from the Y-axis direction (away from the light emitting device 700). Therefore, the main light emitting surface of the light emitting structure 11 is substantially perpendicular to the light emitting surface of the light emitting device 700.
In addition, although the lower surface 174 of the second reflective layer 17 is planar and parallel to the upper surface 173 of the second reflective layer 17 in fig. 12B, the present invention is not limited thereto, and any optical design that facilitates extraction of light from the light emitting device 700 may be applied to the second reflective layer 17. For example, by changing the shape of the upper surface 121 of the light transmissive body 12 (i.e., changing the lower surface 174 of the second reflective layer 17), the light of the light emitting structure 11 may be directed toward the third side surface 1105 to exit the light emitting structure 700. The related structure and fabrication process will be described later.
The light emitting device 700 has a height (H)0) No greater than 0.3mm (< 0.3mm), a thinner height helps increase the field of application of the light emitting device 700 (e.g.: cell-phone, liquid crystal display, wearable device (watch, bracelet, necklace, etc.)). As described above, since the main light-emitting surface of the light-emitting structure 11 is different from the light-emitting surface of the light-emitting device 700, that is, the light-emitting structure 11 and the light-emitting device 700 have different light-emitting directions, the overall height (Z direction) of the light-emitting device 700 is not increased when the main light-emitting area (XY plane) of the light-emitting structure 11 is increased. Since increasing the main light emitting area of the light emitting structure 11 increases the light emitting amount of the light emitting structure 11, and the overall luminous flux of the light emitting device 700 is also increased, however, the overall height of the light emitting device 700 is not increased, and the application field of the light emitting device 700 is not limited.
Fig. 13A to 13F are cross-sectional views illustrating a manufacturing process of a light emitting device according to an embodiment of the invention, and fig. 14A to 14F are top views of fig. 13A to 13F, respectively. Fig. 13A to 13F are cross-sectional views taken along line W-W in fig. 14A to 14F, respectively. For the sake of simplicity, the light emitting structure 11 described later is only illustrated as a rectangle in the drawings, however, in the top view, other shapes, such as a square, a trapezoid, a parallelogram, a rhombus, a triangle, a pentagon, a hexagon, and a circle, can also be applied to the embodiments of the present invention. Moreover, for clarity, each structure is drawn as a solid line whether it is non-transparent, or translucent.
Referring to fig. 13A and 14A, a carrier 22, a glue 21 attached on the carrier 22, and a plurality of light emitting structures 11 disposed on the glue 21 are provided. In this embodiment, the light emitting structure is attached to the adhesive 21 by the side of the first electrode 1118. The number and arrangement of the light emitting structures 11 in fig. 13A are merely exemplary and not limited thereto.
Referring to fig. 13B and 14B, a wavelength converter 13 completely covers the upper surface 1101, the side surfaces 1103-1106, and a portion of the lower surface 1102 of the light emitting structure 11. The wavelength converter 13 may be formed on the light emitting structure 11 by dispensing (spraying), coating (coating), spraying (dispensing), printing (screen printing), or molding (molding).
Referring to fig. 13C to 13D and 14C to 14D, a transparent body not containing wavelength conversion particles completely covers the wavelength conversion body 13. The transparent body is then cured to form the light transmissive body 12. The transparent body may be formed by dispensing (spraying), coating (coating), spraying (painting), printing (printing), molding (molding), or the like. Next, a cutting blade 23 is provided and a cutting step is performed along the cutting lines L in the X direction and the Y direction to form a plurality of grooves 231, wherein the grooves 231 are located in the light-transmitting body 12 and the wavelength converting body 13 and expose the adhesive material 21. In the cutting step, the groove 231 is located between the two light emitting structures 11, and the light transmissive body 12 is divided into a plurality of regions that are not connected to each other. The light-transmitting body 12 and the wavelength converter 13 cover the four sides and the upper surface of the light-emitting structure 11.
Referring to fig. 13E to 13F and 14E to 14F, a plurality of reflective particles (not shown) are mixed into a matrix to form a glue layer in an uncured state (the color of the glue layer may be determined by the mixed reflective particles, and the common color is white). Then, the light-transmitting body 12 and the groove 231 are covered by a glue layer (preferably, the groove 231 is completely covered by the glue layer or only a small part of the area is not covered or bubbles remain); the glue layer is completely cured, thereby forming the second reflective layer 17. The height of the second reflective layer 17 is greater than the height of the transparent body 12, that is, the second reflective layer 17 covers four side surfaces 123-126 and the upper surface 121 of the transparent body 12 (see fig. 12A and 12B). The second reflective layer 17 can be formed by dispensing (spraying), coating (coating), spraying (dispensing), printing (screen printing), and the like. In another embodiment, the second reflective layer 17 may be a preformed reflective sheet attached to the transparent body 12. The manner of fitting can refer to the related paragraphs. Finally, the dicing step is performed along the dicing lines L (X direction and Y direction). Then, the adhesive material 21 is heated or irradiated with UV light to separate the light emitting structure 11, the light transmitting body 12, the wavelength converting body 13, and the second reflective layer 17 from the adhesive material 21 to form a plurality of independent light emitting devices.
Referring to fig. 13E to 13F and 14E to 14F, the cutting line L in the X direction cuts or penetrates through the light-transmissive body 12, so that the second reflective layer 17 covers only three sides of the light-transmissive body 12 and exposes one side of the light-transmissive body. By changing the cutting position, the light-transmitting body 12 can cover the thickness (T) of the first side 1103 and the third side 1105 of the light-emitting structure 111And T2) The same or different. For example, when a portion of the light-transmissive body 12 is removed in the cutting step, the thickness of two sides of the light-transmissive body 12 is different (T)1≠T2). Alternatively, the cutting position is controlled so that the transparent body 12 is not removed in the cutting step, and thus the thicknesses of both sides of the transparent body 12 are the same (T)1＝T2)。
Finally, optionally, the first reflective layer 14 and the extension electrodes 15A and 15B as shown in fig. 12B can be further formed, and the detailed description can refer to other related paragraphs.
Fig. 15A to 15F are sectional views illustrating a manufacturing process of a light emitting device according to another embodiment of the invention, and fig. 16A to 16F are top views of fig. 15A to 15F, respectively. Fig. 15A to 15F are cross-sectional views taken along line W-W in fig. 16A to 16F, respectively. The detailed description of fig. 15A to 15B can refer to the corresponding paragraphs of fig. 13A to 13B.
Referring to fig. 15C to 15D and 16C to 16D, a cutting blade 23A is provided and a cutting step is performed along the cutting line L in the X direction to form a plurality of grooves 231 in the light transmissive body 12 and expose the wavelength converters 13. Further, the cutting blade 23A cuts at different depths of the Z axis along the Y axis, and since the cutting blade 23A has an arc-shaped cross section, the upper surface 121 of the light-transmissive body 12 has a wavy shape.
For example, referring to fig. 17A, the cutting blade 23A is located between the light emitting structures 11D and 11E and cuts downward (-Z direction) to the adhesive material 21 to form the groove 231, wherein the cutting depth is H1.
As shown in fig. 17B, the cutting blade 23A is moved to the Y axis by a first distance (S1) and positioned above the light emitting structure 11E and cuts a portion of the light transmissive body 12, wherein the cutting depth is H2(H2 < H1).
As shown in FIG. 17C, the cutting blade 23A is moved a second distance (S2) toward the Y axis and still above the light emitting structure 11E, and then cuts a portion of the light transmissive body 12, wherein the cutting depth is H3(H3 > H2; H3 < H1).
As shown in fig. 17D, the cutting blade 23A is moved to the Y axis by a third distance (S3) and still above the light emitting structure 11E, and then cuts the portion of the light transmissive body 12, wherein the cutting depth is H4(H4 > H3 > H2; H4 < H1).
As shown in fig. 17E, the cutting blade 23A is moved to the Y axis by a fourth distance (S4) and still above the light emitting structure 11E, and then cuts the portion of the light transmissive body 12, wherein the cutting depth is H5(H5 > H4 > H3 > H2; H5 < H1).
As shown in fig. 17F, the cutting blade 23A is moved a fifth distance (S5) toward the Y axis and still above the light emitting structure 11E, and then cuts the portion of the light transmissive body 12, wherein the cutting depth is H6(H6 > H5 > H4 > H3 > H2; H6 < H1).
Finally, as shown in fig. 17A, when the cutting blade 23A moves out of the light emitting structure 11E (not located on the light emitting structure 11E) and is located between the light emitting structures 11E and 11F, the cutting blade cuts downward (-Z direction) and cuts to the adhesive material 21 (with a cutting depth H1) to form the groove 231, so that the upper surface 12 of the light transmissive body 12 has a wavy shape.
In the above method, the cutting blade 23A is always displaced to the Y axis and the cutting depth is changed in the Z axis, so that the light-transmitting body 12 can have the upper surface 121 with different shapes. Furthermore, the shape of the cutting burr also causes the upper surface 121 to have a different profile. For example: as shown in fig. 18A, the upper surface 121 of the light-transmitting body 12 has a stepped shape; as shown in fig. 18B, the upper surface 121 of the light-transmitting body 12 is a continuous smooth slope; as shown in fig. 18C, the upper surface 121 of the light-transmissive body 12 has a sawtooth-shaped profile.
Furthermore, the cutting position is changed to make the upper surface of the light-transmitting body 12 have different shapes. As shown in fig. 18D, the cutting blade moves to the top of the light emitting structure and cuts downward, so that the light transmissive body 12 has a plane 127 and an inclined plane 128. The plane 127 is parallel to the upper surface 173 of the second reflective layer 17 and the inclined plane 128 is inclined with respect to the upper surface 173 of the second reflective layer 17. The plane 127 and the inclined plane 128 have a portion located above the light emitting structure. Compared with the upper surface 121 of the light-transmitting body 12 shown in fig. 12, the upper surface 121 of the light-transmitting body 12 above the light-emitting structure has a part or all of a non-planar structure (e.g., a slope, a wave, a step, etc.), which helps to reflect the light emitted by the light-emitting structure toward the side surface to leave the light-emitting structure (see fig. 12B) and increase the light-emitting brightness.
As shown in fig. 18E, the use of an asymmetric cutting blade may also form the upper surface 121 with a flat surface 127 and a beveled surface 128. In addition, the structure shown in fig. 18E can be obtained by performing the cutting step only once, so that the manufacturing process of the embodiment is simple and the manufacturing process cost and time can be reduced compared to the manufacturing processes shown in fig. 17A to 17F.
Referring to fig. 15E to 15F and 16E to 16F, a plurality of reflective particles (not shown) are mixed into the matrix to form a glue layer in an uncured state (the color of the glue layer may be determined by the mixed reflective particles, and the common color is white). The light-transmitting body 12 and the trench 231 are covered by a glue layer (preferably, the trench 231 is completely covered by the glue layer or only a small portion of the trench is uncovered or air bubbles remain). The glue layer is subsequently completely cured, thereby forming the second reflective layer 17. Further description of the second reflective layer 17 may refer to the preceding related paragraphs. Then, a dicing step is performed along the dicing lines L (X direction and Y direction). Then, the glue material 21 is heated or the glue material 21 is irradiated by UV light to separate the glue material 21 to form a plurality of light emitting devices independent of each other.
Referring to fig. 15F, a cutting line L along the X direction cuts or penetrates the light-transmissive body 12, so that the second reflective layer 17 covers only three sides of the light-transmissive body 12, and exposes one side of the light-transmissive body 12. In addition, since the upper surface 121 of the light-transmitting body 12 has a wavy shape, the lower surface 174 of the second reflective layer 17 (the surface in contact with the upper surface 121 of the light-transmitting body 12) also has a wavy shape.
Fig. 19 is a cross-sectional view of a light emitting device 800 in accordance with an embodiment of the present invention. For simplicity, the light emitting structure 11 of fig. 19 is only illustrated as a rectangle, however, in the top view, other shapes such as a square, a trapezoid, a parallelogram, a rhombus, a triangle, a pentagon, a hexagon, a circle can also be applied to the embodiments of the present invention.
The light emitting device 800 has a similar structure to the light emitting device 100. Wherein elements or devices corresponding to the same reference signs or signs have similar or identical elements or devices. Fig. 19 depicts a cross-sectional view of only light emitting device 800, and additional views may be referenced to the description of light emitting device 100. Briefly, the light emitting device 800 includes a light emitting structure 11, a light transmissive body 12 including a plurality of wavelength converting particles 131, a first reflective layer 14, extension electrodes 15A and 15B, and a second reflective layer 17.
Fig. 19 is similar to fig. 2C, except for the shape of the second reflective layer. As shown in fig. 19, the second reflective layer 17A has an outer surface 171A and an inner surface 172A. The outer surface 171A is substantially planar (straight in FIG. 19) and perpendicular to the upper surface 121. The inner surface 172A has a sloped surface (shown as a diagonal line in FIG. 19) 172A1 and a flat surface (shown as a straight line in FIG. 19) 172A 2. The ramp 172a1 is inclined relative to the upper surface 121 and the flat surface 172a2 is perpendicular to the upper surface 121. The inclined surface 172a1 extends from the first reflective layer 14 to the Z-axis and has a height greater than that of the light emitting structure 11, and the inclined surface 172a1 can reflect the light emitted by the light emitting structure 11 to leave the light emitting device 800 toward the top of the light transmissive body 12. The first side surface 123 and the third side surface 125 of the light-transmitting body 12 are in direct contact with the inner surface 172A of the second reflective layer 17A, and thus the shapes of the first side surface 123 and the third side surface 125 are the same as the inner surface 172A of the second reflective layer 17A. The inclined plane 172A1 and the first reflective layer 14 form an included angle (theta) of 60-80 degrees. The flat surface 172A2 extends from the ramp surface 172A1 toward the Z-axis.
Fig. 19A to 19C are cross-sectional views of a simplified light emitting device. The simplified light emitting device was used in a simulation experiment to obtain the relationship between the slope height (μm), the plane height (μm), the angle (θ) and the luminous flux (mW). Table one shows the simulation results of different angles (θ) and luminous flux. The simulation results are from the assumption that the thickness (Y direction) of the light emitting device is 1.1mm and the height (Z direction) is 0.35 mm. As can be seen from table one, when the angle (θ) is larger, the light emitted from the light emitting structure 11 is less likely to be reflected at the inclined surface 172a1 toward the light transmissive body 12 and then leave the light emitting device, and thus the light flux of the light emitting device is smaller. In addition, since the plane 172a2 is located above the inclined plane 172a1 so that the light emitting areas (Ea) of the light emitting devices at the three angles are the same, the light emitting angles of the light emitting devices in fig. 19A to 19C are substantially the same. From the above, the inclination angle (θ) can change the luminous flux of the light-emitting device, and the plane 172a2 can fix the light-emitting angle of the light-emitting device to a specific value (e.g., 120 degrees). In other words, the light-emitting device can have a predetermined luminous flux and a predetermined light-emitting angle by the design of the inclined plane and the flat plane.
Watch 1
Height of bevel (mum)
Height of plane (μm)
Angle (theta)
Luminous flux (mW)
250
100
60
7.4
250
100
70
7.37
250
100
80
7.33
When the height of the light emitting device is a fixed value, if the inclination angle (θ) of the inclined surface 172a1 is smaller, the thickness (Y direction) of the light emitting device becomes larger, and the light emitting device may not be easily applied to some fields because the size of the light emitting device becomes larger. Therefore, the inclination angle of the inclined surface 172a1 is designed in consideration of the application.
Fig. 20A to 20G are sectional views of a manufacturing process of a light-emitting device according to the present invention, and fig. 21A to 21G are top views of fig. 20A to 20G, respectively. Fig. 20A to 20G are cross-sectional views taken along line W-W in fig. 21A to 21G, respectively. For the sake of simplicity, the light emitting structure 11 described later is only illustrated as a rectangle in the drawings, however, in the top view, other shapes, such as a square, a trapezoid, a parallelogram, a rhombus, a triangle, a pentagon, a hexagon, and a circle, can also be applied to the embodiments of the present invention. Moreover, for clarity, each structure is drawn as a solid line whether it is non-transparent, or translucent. The detailed description of fig. 20A to 20B and fig. 21A to 21B can refer to fig. 3A to 3B and fig. 4A to 4B and the corresponding paragraphs.
Referring to fig. 20C to 20D and fig. 21C to 21D, a glue 26 is provided to be attached to the carrier 27. After the structure of fig. 20B is attached to the adhesive 26 through the transparent body 12, the adhesive 21 is heated or the adhesive 21 is irradiated with UV light, so that the light-emitting structure 11 and the transparent body 12 are separated from the adhesive 21 (the adhesive 21 and the carrier 22 are not shown in fig. 20C), and the electrodes 1118 and 1119 are exposed (the electrode 1119 is not shown in the figure due to the view).
Next, a first cutting blade 23B is provided to perform a cutting step along the cutting line L (X direction) and cut the light-transmitting body 12 from the electrode 1118 side. The first cutter 23B has a triangular cross section and a cutting depth (H7) smaller than the height (Z direction) of the light-transmitting body 12 but higher than the height of the light-emitting structure 11. Since the first cutting blade does not completely cut the light-transmitting body 12, a portion of the light-transmitting bodies 12 are still connected to each other.
Referring to fig. 20D, 20E, 21D and 21E, a second cutting blade 23A is provided to cut the adhesive material 26 along the cutting line L (X direction), and at this time, the second cutting blade 23A completely cuts the light-transmitting body 21 and forms the groove 231.
Referring to fig. 20F to 20G and 21F to 21G, a plurality of reflective particles (not shown) are mixed into the matrix to form a glue layer in an uncured state (the color of the glue layer may be determined by the mixed reflective particles, and the common color is white). An adhesive layer is added to cover the light-transmissive body 12 and the trench 231 (preferably, the trench 231 is completely covered by the adhesive layer or only a small portion of the trench is uncovered or air bubbles remain). The glue layer is completely cured, thereby forming the second reflective layer 17. Further description of the second reflective layer 17 may refer to the preceding related paragraphs. Then, a dicing step is performed along the dicing lines L (X direction and Y direction) by the second dicing blade 23A. Then, the adhesive 26 is heated or irradiated with UV light to separate the light emitting structure 11, the transparent body 12 and the second reflective layer 17 from the adhesive 26 to form a plurality of independent light emitting devices.
Since the glue layer covers the transparent body 12 from the side of the electrode 1118 and fills the trench 231, the glue layer may cover part of the electrodes 1118 and 1119 in this step (the electrode 1119 is not shown in the figure due to the view). In another example, a passivation layer (e.g., photoresist, not shown) may be formed on the electrode 1118, and then a glue layer is formed. Thus, the glue layer covers the passivation layer without directly contacting the electrodes 1118 and 1119. After the above steps are completed, the passivation layer is removed to expose the electrodes 1118 and 1119. By the protective layer, the subsequent step of cleaning the adhesive layer on the electrodes 1118 and 1119 can be omitted. Optionally, the first reflective layer 14 and the extension electrodes 15A and 15B may be further formed, and the detailed description thereof may refer to other related figures or paragraphs.
In the manufacturing process of fig. 20A to 20G, two kinds of cutting blades of different cutting heads are used to form the light-transmitting body 12 having a slope and a plane (refer to the description of fig. 19). However, the shape of the cutting blade can be designed, and only one cutting step is needed to obtain the same structure as the two cutting steps shown in fig. 20C and 20D.
Fig. 22A is a cross-sectional view of a light emitting device 900 according to another embodiment of the invention. Referring to fig. 22A, the second reflective layer 17B has an outer surface 171B and an inner surface 172B. The outer surface 171B is substantially planar (straight in fig. 22A) and perpendicular to the upper surface 121. The inner surface 172B is a sloped surface (sloped in fig. 22A) and is inclined with respect to the upper surface 121. The inner surface 172B extends from the first reflective layer 14 to the upper surface 121 of the light transmissive body 12 in the Z-axis direction. The inner surface 172B and the first reflective layer 14 form an included angle (θ) of 60 to 80 degrees. The inner surface 172B reflects light emitted from the light emitting structure 11 toward the upper surface 121 of the light transmissive body 12.
Fig. 22B is a cross-sectional view of a light emitting device 1000 according to an embodiment of the invention. Fig. 22C is a cross-sectional view of a light emitting device 1100 according to an embodiment of the invention. Referring to fig. 22B and 22C, the second reflective layer 17C has an outer surface 171C and an inner surface 172C. The outer surface 171C is substantially planar and perpendicular to the upper surface 121. The inner surface 172C is a sloped surface and is inclined with respect to the upper surface 121. The inner surface 172C extends from the first reflective layer 14 toward the Z-axis and does not touch the upper surface 121 of the transparent body 12 and is spaced apart from the upper surface by a distance (D2); d2 ≦ 800 μm (D2 ≦ 20 μm, 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm) for different D2 values to be suitable for different fields of application. In other words, a portion of the first side surface 123 (or the second side surface 125) of the light-transmitting body 12 is not covered by the second reflective layer 17 and is exposed to the external environment. The first side surface 123 (or the second side surface 125) exposed to the outside is substantially flush with the outer surface 171C of the second reflective layer 17C. As shown in fig. 22B and 22C, since the transparent body 12 covers the second reflective layer 17, the transparent body 12 is seen directly in the top view, and the second reflective layer 17 is hidden and not present. The inner surface 172C may reflect light emitted from the light emitting structure 11 to be directed toward the upper surface 121 of the light transmissive body 12.
In fig. 22B, the slope (172C) of the light emitting device 1000 is higher than the height of the light emitting structure 11. In fig. 22C, the slope (172C) of the light emitting device 1100 is lower than the height of the light emitting structure 11. As shown in fig. 22C, the slope (172C) has a height (D3) and the light emitting structure 11 has a height (D4); and D3-D4. Table two shows the experimental results of Δ D and the light emitting angle of the light emitting device.
Watch two
D2(μm)
D3(μm)
D4(μm)
Angle (theta)
ΔD(μm)
Luminous angle
280
70
150
60
-80
140
210
140
150
60
-10
135
150
200
150
60
50
120
120
230
150
60
80
120
70
280
150
60
130
130
As can be seen from table two, when D3 is smaller than D4, the larger the absolute value of Δ D, the larger the light emission angle of the light-emitting device 1100, and the light emission angle of the light-emitting device 1100 approaches the light emission angle of the light-emitting structure 11 not covered with the light-transmitting body 12. Unlike fig. 19, in fig. 22B and 22C, the upper side of the inclined plane (172C) is covered by the light-transmitting body 12, and the section including the plane 172a2 in fig. 19 is not included. As shown in fig. 22B, when the section including the inclined surface 172C has a height greater than that of the light-emitting structure 11, the light emitted by the light-emitting device 1000 is reflected by the inclined surface 172C and exits the light-emitting device 1000 toward the upper side of the light-transmitting body 12. The light emitting angle (e.g., 140 degrees) of the light emitting structure 11 can be reduced by the slope 172C (e.g., 120 degrees) of the light emitting device 1000. In contrast, as shown in fig. 22C, when the inclined surface 172C has a height smaller than that of the light-emitting structure 11, since a portion of the light emitted by the light-emitting structure 11 is not reflected by the inclined surface 172C and directly leaves the light-emitting device 1100, the light-emitting angle of the light-emitting device 1100 is larger than the light-emitting angle of the light-emitting device 1000 but smaller than the light-emitting angle of the light-emitting structure 11 (e.g., larger than 120 degrees and smaller than 140 degrees). Through the design of the section height at the inclined plane, the light-emitting device can have different light-emitting angles, and the application field of the light-emitting device is increased.
In addition, as can be seen from tables one and two, the light-emitting device can have a small predetermined light-emitting angle (e.g., 120 degrees) by a mixed arrangement of a plane and a slope (the structure shown in fig. 19) or by an arrangement in which the slope is higher than the light-emitting structure (the structure shown in fig. 22B). However, compared to the light emitting device in which the second reflective layer is only disposed on a plane (as shown in fig. 2C) or is not disposed, the light emitting device can still have the brightness of the light emitting device increased by only disposing the second reflective layer (higher than or lower than the light emitting structure) on the inclined plane.
Fig. 23A to 23F are cross-sectional views illustrating a manufacturing process of a light emitting device according to an embodiment of the invention, and fig. 24A to 24F are top views of fig. 23A to 23F, respectively. Fig. 23A to 23F are cross-sectional views taken along line W-W in fig. 24A to 24F, respectively. For the sake of simplicity, the light emitting structure 11 described later is only illustrated as a rectangle in the drawings, however, in the top view, other shapes, such as a square, a trapezoid, a parallelogram, a rhombus, a triangle, a pentagon, a hexagon, a circle, may also be applied to the embodiments of the present invention. Moreover, for clarity, each structure is drawn as a solid line whether it is non-transparent, or translucent. The descriptions of fig. 23A to 23B and fig. 24A to 24B may refer to fig. 3A to 3B and fig. 4A to 4B and the corresponding paragraphs.
Referring to fig. 23C to 23D and fig. 24C to 24D, a glue 26 is provided to be attached to the carrier 27. After the structure of fig. 23B is attached to the adhesive 26 from one side of the transparent body 12, the adhesive 21 is heated or irradiated with UV light to separate the light-emitting structure 11 and the transparent body 12 from the adhesive 21 (the adhesive 21 and the carrier 22 are not shown in fig. 23C), and the electrodes 1118 and 1119 are exposed (the electrode 1119 is not shown in the figure due to the view).
Next, a cutting step is performed by a cutter 23B along the cutting line L (X direction) to cut the light-transmitting body 12 from the electrode 1118 side to the adhesive 26 (i.e., the cutting depth (H8) is substantially equal to the height of the light-transmitting body 12) and form the groove 231. The light-transmitting body 12 is divided into a plurality of regions (a1 to A3) that are not connected to each other.
Referring to fig. 23E to 23F and 24E to 24F, a plurality of reflective particles (not shown) are mixed into the matrix to form a glue layer in an uncured state (the color of the glue layer may be determined by the mixed reflective particles, and the common color is white). A glue layer is added to cover the light-transmissive body 12 and the trench 231 (preferably, the trench 231 is completely covered by the glue layer or only a small portion of the trench is uncovered or air bubbles remain). The glue layer is completely cured, thereby forming the second reflective layer 17. Further description of the second reflective layer 17 may refer to the preceding related paragraphs. Then, a dicing step is performed along the dicing lines L (X direction and Y direction). Then, the adhesive 26 is heated or irradiated with UV light to separate the light emitting structure 11, the transparent body 12 and the second reflective layer 17 from the adhesive 26 to form a plurality of independent light emitting devices.
In one embodiment, the transparent body 12 and the second reflective layer 17 are cut simultaneously during the cutting process, so that a portion of the transparent body 12 is not covered by the second reflective layer 17 and is exposed to the external environment (the detailed description can refer to the description of fig. 22B). Alternatively, the height of the second reflective layer 17, or the size of the area where the light-transmitting body 12 and the second reflective layer 17 meet, or the exposed area (height) of the light-transmitting body 12 can be changed by changing the cutting position. In addition, the light-emitting device shown in fig. 22A can also be formed by changing the cutting position, and cutting only the second reflective layer 17 so that the second reflective layer 17 covers the light-transmitting body 12.
Fig. 25A to 25D are perspective views illustrating a manufacturing process of the light emitting device of the present invention. Fig. 26A to 26C are top views of fig. 25B to 25D. Similarly, for the sake of brevity, the light emitting structure 11 described later is only illustrated as a rectangle in the drawings, however, in the top view, other shapes such as a square, a trapezoid, a parallelogram, a rhombus, a triangle, a pentagon, a hexagon, a circle can also be applied to the embodiments of the present invention. Moreover, for clarity, each structure is drawn as a solid line whether it is non-transparent, or translucent.
Referring to fig. 25A, a carrier 22, a plastic material 21 attached on the carrier 22, and a plurality of light emitting structures 11 disposed on the plastic material 21 are provided. In one embodiment, the light emitting structure 11 is attached on the adhesive 21 by the sides of the first electrode 1118 and the second electrode 1119 (not shown). The number and arrangement of the light emitting structures 11 in fig. 25A are merely exemplary and not limited thereto.
Referring to fig. 25B and fig. 26A, a reflective frame 37 having a plurality of through holes 371(through holes) is provided and disposed on the adhesive material 21 such that the plurality of light emitting structures 11 are located in the through holes 371 and the reflective frame 37 surrounds the plurality of light emitting structures 11. The reflective frame 37 and the adhesive 21 together form a groove 38, and the reflective frame 37 has an inclined inner sidewall 371.
Referring to fig. 25C and 26B, a transparent body containing wavelength conversion particles is filled in the groove 38 and completely covers the light emitting structure 11. The transparent body is then cured to form the light transmissive body 12.
Referring to fig. 25D and 26C, a cutting step is performed along the X direction to cut the reflective frame 37, and then the transparent body 12 and the reflective frame 37 are cut along the Y direction to form a plurality of light emitting devices independent of each other. Similarly, if only the reflective frame 37 (the second reflective layer 17) is cut in the cutting process, the light emitting device 900 as shown in fig. 22A is formed. Alternatively, when the light-transmitting body 12 and the reflection frame 37 (second reflection layer 17) are cut at the same time, the light-emitting device 1000 shown in fig. 22B is formed.
FIG. 27A is a cross-sectional view of a backlight unit of a side-lit LCD. The backlight unit includes a light emitting source 901, a light guide plate 902, and a diffusion plate 903. The light source 901 includes a carrier 9011, a plurality of light emitting devices 100 disposed on the carrier 9011, and a circuit structure (not shown) formed on the carrier 9011 for controlling the light emitting devices 100. The light emitting sources 901 are disposed on both sides of the light guide plate 902. When the light emitting device 100 emits light, the light (R) emitted by the light emitting device 100 is emitted outward (away from the light emitting device 100) from the Z-axis direction, so that the carrier plate 9011 is disposed perpendicular to the light guide plate 902 (i.e., the light emitting surface of the light emitting device 100 is perpendicular to the carrier plate 9011), and the light (R) can be effectively emitted into the light guide plate 902. When the light (R) enters the light guide plate 902, the light guide plate 902 changes the direction of the light (R) toward the diffuser plate 903. Optionally, a reflector 904 may be disposed on the light guide plate 902 opposite to the diffuser plate 903 for reflecting the light (R). The extension electrodes 15A and 15B of the light-emitting device 100 are fixed to the circuit structure of the carrier board 9011 by solder (holder). In an embodiment, the carrier 9011 and the reflector 904 may be integrally formed and L-shaped, and the light emitting device 100 is disposed only on one side of the light guide plate 902, so as to reduce the manufacturing cost and simplify the assembly process.
Fig. 27B is a perspective view of the light-emitting source 901 and the light guide plate 902 in fig. 27A. The light emitting devices 100 are arranged in a one-dimensional array along the X direction, and the second reflective layer 17 is parallel to the long side of the carrier 9011. In the present embodiment, the number and arrangement of the light emitting devices 100 are merely exemplary and not limited thereto. Since the light emitting angle of the light emitting devices 100 in the long side direction (X direction) is 130 to 150 degrees, the distance (D5) between the light emitting devices 100 of the present invention is 12mm to 15mm and no dark area is generated in the light guide plate 902. The distance (D5) may be between 4mm and 15mm depending on the application.
FIG. 28 is a cross-sectional view of a backlight unit of a side-lit LCD. Similar to fig. 27A, but in fig. 28 the light-emitting device 100 is replaced with a light-emitting device 600. The light emitting device 600 has only one side provided with the second reflective layer 17 and the side not provided with the second reflective layer 17 faces the reflector 904, so that the light (R) of the light emitting device 600 can be reflected by the second reflective layer 17 to be directed to the reflector 904, and then the light is directed to the diffusion plate 903 through the reflector 904, thereby increasing the overall brightness of the side-view liquid crystal display.
Fig. 29 is a cross-sectional view of a backlight unit of a side-view liquid crystal display. The light source 901 includes a carrier 9011, and a plurality of light emitting devices 700 disposed on the carrier 9011. Since most of the light emitting device 700 is emitted outward (away from the light emitting device 700) from the Y-axis direction, the carrier 9011 is disposed parallel to the light guide plate 902 (i.e., the light emitting surface of the light emitting device 700 is parallel to the carrier 9011), so that the light (R) can be effectively emitted into the light guide plate 902.
It should be understood that the above-described embodiments of the present invention may be combined with or substituted for one another as appropriate, and are not intended to be limited to the particular embodiments shown. The examples are given solely for the purpose of illustration and are not intended to limit the scope of the invention. Any obvious modifications or alterations to the invention may be made by anyone without departing from the spirit and scope of the invention.
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