阅读说明：本技术 电子装置 (Electronic device ) 是由 郑雅文 黄郁宸 陈顺政 林俊雄 姚怡安 于 2020-05-25 设计创作，主要内容包括：本发明公开了一种电子装置,包括：一背光模块。其中,背光模块包括：一基板；多个发光二极管,设置于该基板上,且该些发光二极管为蓝光发光二极管；一保护层,设置于该基板上且覆盖该些发光二极管；以及一光色转换单元,设置于该些发光二极管上。(The invention discloses an electronic device, comprising: a backlight module. Wherein, backlight module includes: a substrate; a plurality of light emitting diodes arranged on the substrate, wherein the light emitting diodes are blue light emitting diodes; a protective layer arranged on the substrate and covering the light emitting diodes; and a light color conversion unit arranged on the light emitting diodes.)

1. An electronic device, comprising:

a backlight module, comprising:

a substrate;

a plurality of light emitting diodes arranged on the substrate, wherein the light emitting diodes are blue light emitting diodes;

a protective layer arranged on the substrate and covering the light emitting diodes; and

and the light color conversion unit is arranged on the light emitting diodes.

2. The electronic device of claim 1, wherein the passivation layer directly contacts the light emitting diodes.

3. The electronic device of claim 1, wherein the protective layer has a refractive index of 1.4 to 1.6.

4. The electronic device of claim 1, wherein the protective layer comprises an optical adhesive, a silicone adhesive, a translucent adhesive, or a combination thereof.

5. The electronic device of claim 1, wherein the backlight module further comprises a reflective layer disposed on the substrate and between two adjacent light emitting diodes of the plurality of light emitting diodes; wherein a distance is provided between the surface of the reflective layer and the optical conversion unit, a distance is provided between two adjacent light emitting diodes in the light emitting diodes, and the ratio of the distance to the distance is greater than 0.09 and less than 0.38.

6. The electronic device of claim 1, wherein the backlight module further comprises a microstructure array optical film disposed on the protective layer.

7. The electronic device of claim 6, wherein the micro-structure array optical film has an upper surface and a lower surface, the upper surface is opposite to the lower surface, and the lower surface faces the protection layer; the upper surface is provided with a plurality of polyhedral grooves which are arranged in an array mode, the widths of the polyhedral grooves are respectively between 50 mu m and 180 mu m, and the depths of the polyhedral grooves are respectively between 10 mu m and 50 mu m.

8. The electronic device of claim 7, wherein the bottom surface has a plurality of pillar-shaped protrusions, the pillar-shaped protrusions are staggered, and a recess is formed between adjacent pillar-shaped protrusions; wherein the width of the columnar protrusion is between 35 μm and 115 μm, and the depth of the concave portion is between 1 μm and 30 μm.

9. The electronic device of claim 6, wherein the bottom surface has at least one reflective unit disposed thereon, and the at least one reflective unit is disposed corresponding to at least one of the LEDs.

10. The electronic device of claim 1, wherein the backlight module further comprises a light recycling layer disposed on the protective layer, and the light color conversion unit is disposed on the light recycling layer; wherein the light transmittance of the light recycling layer between 420nm and 480nm is more than 75%, and the light transmittance of the light recycling layer between 550nm and 750nm is less than 10%.

Technical Field

The present disclosure relates to electronic devices, and particularly to an electronic device with a backlight module having a special structure.

Background

In a display device, a direct type backlight module using light emitting diodes as a light source is combined with a local dimming (local dimming) technology to achieve the effect of a High Dynamic Range (HDR), however, whether the technology can replace the prior art depends on the manufacturing cost.

When the number of the light emitting diodes used is reduced, although the manufacturing cost can be reduced, the problem of insufficient brightness is generated. In addition, when the led is used as a light source, the hot spot of the led may cause poor visual effect and cause power consumption.

In view of the above, there is a need to develop a display device having a novel backlight module, so as to achieve the purposes of reducing the light source (i.e., light emitting diode) arrangement density of the backlight module, reducing the manufacturing cost, improving the light efficiency, reducing the power consumption, or improving the visual effect.

Disclosure of Invention

The present invention provides an electronic device, comprising: a backlight module. Wherein, backlight module includes: a substrate; a plurality of light emitting diodes arranged on the substrate, wherein the light emitting diodes are blue light emitting diodes; a protective layer arranged on the substrate and covering the light emitting diodes; and a light color conversion unit arranged on the light emitting diodes.

Other novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.

Drawings

Fig. 1 is a schematic cross-sectional view illustrating a backlight module of an electronic device according to an embodiment of the invention;

FIG. 2 is a schematic cross-sectional view illustrating a backlight module of an electronic device according to another embodiment of the invention;

FIG. 3A is a schematic perspective view of a microstructure array optical film according to an embodiment of the invention;

FIG. 3B is a schematic cross-sectional view of the microstructure array optical film of FIG. 3A;

FIG. 4A is a schematic perspective view of a microstructure array optical film according to another embodiment of the invention;

FIG. 4B is a schematic cross-sectional view of the microstructure array optical film of FIG. 4A;

FIG. 5 is a schematic cross-sectional view illustrating a backlight module of an electronic device according to another embodiment of the invention;

FIG. 6 is a schematic cross-sectional view illustrating a backlight module of an electronic device according to still another embodiment of the invention;

fig. 7 is a schematic cross-sectional view of a backlight module of an electronic device according to another embodiment of the invention.

Description of the symbols:

10 backlight module

11 substrate

12 reflective layer

121 hole

122 surface of the substrate

13 light emitting diode

131 upper light-emitting surface

14 protective layer

21 first brightness enhancement film

22 diffusion membrane

23 second brightness enhancement film

24 light color conversion unit

241 upper surface

25 light recovery layer

27 microstructured array optical film

271 upper surface

272 lower surface

273 polyhedral groove

274 columnar protrusions

275 recess

276 reflection unit

3 frame

D_A，D_BDepth of field

W_A，W_BWidth of

OD distance

P pitch

Detailed Description

Various embodiments of the invention are provided below. These examples are intended to illustrate the technical contents of the present invention, and are not intended to limit the scope of the claims of the present invention. Features of one embodiment may be combined, separated, and adapted for other embodiments without departing from the spirit of the invention.

It should be noted that, unless otherwise specified herein, the inclusion of "a" or "an" element is not limited to inclusion of a single such element, but may include one or more such elements.

Moreover, unless specifically stated otherwise, the ordinal numbers "first", "second", etc., are used to distinguish between elements having the same name and do not denote any order, hierarchy, order of execution, or order of processing. A "first" element and a "second" element may be present together in the same component or separately in different components. The presence of an element having a higher ordinal number does not necessarily indicate the presence of another element having a lower ordinal number.

In this context, unless specifically stated otherwise, the term "a" or "and/or" feature "means the presence of a, either alone or in combination with b; by the features A "and" or "and" feature B ", it is meant that A and B are present simultaneously; the terms "comprising," "including," "having," "containing," and "containing" are intended to be inclusive and not limiting.

In addition, the terms "upper", "lower", or "between" and the like are used herein only for describing relative positions between a plurality of elements, and may be generalized in explanation to include the case of inversion.

Further, herein, unless otherwise specified, a position referred to in the specification and claims, such as "on," "over," or "above," may mean directly contacting another element, or may mean not directly contacting the other element. Furthermore, where the specification and claims refer to a location, such as "under," "lower," or "beneath," they may refer to being in direct contact with another element or may refer to being not in direct contact with another element. If an element is referred to as being "on" another element, it can be directly on the other element or there can be other elements between the two, but if an element is referred to as being "on" another element, it means that the element directly contacts the other element without any element between the two.

In addition, in the specification and the claims, for example, a term "connected" means not only a direct connection with another element but also an indirect connection and an electrical connection with another element.

Furthermore, the terms such as "adjacent" in the description and in the claims, are used to describe adjacent to each other and do not necessarily indicate contact with each other.

In addition, a value can be the first value, the second value, or another value between the first value and the second value if the value is between the first value and the second value.

Further, as used herein, the term "about" generally means within 20%, or within 10%, or within 5%, or within 3%, or within 2%, or within 1%, or within 0.5% of a given value or range. The amounts given herein are approximate amounts, that is, the meaning of "about" may still be implied without specifically stating "about".

Unless defined otherwise, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present invention and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

In addition, the electronic device disclosed in the present invention may include a display device, a light emitting device, a touch display device (touch display), a curved display device (curved display), or a non-rectangular display device (free shape display), but is not limited thereto. The electronic device can be a bendable or flexible electronic device. The display layer of the electronic display device may include, for example, a liquid crystal (liquid crystal), a Quantum Dot (QD), a fluorescent (fluorescent), a phosphorescent (phor), other suitable display medium, or a combination thereof, but is not limited thereto. In the present invention, the light emitting diode may include, for example, a Light Emitting Diode (LED), a submillimeter light emitting diode (mini LED), a micro light emitting diode (micro LED), or a quantum dot light emitting diode (which may be, for example, a QLED or a QDLED), or other suitable materials or any combinations thereof, but is not limited thereto. The display device may include, for example, a tiled display device, but is not so limited. It should be noted that the electronic device can be any permutation and combination of the foregoing, but not limited thereto. In addition, the exterior of the electronic device may be rectangular, circular, polygonal, a shape with curved edges, or other suitable shapes. The electronic device may have a drive system, a control system, a light source system, a shelf system, or other peripheral systems to support the display device or tiled display device.

Fig. 1 is a schematic cross-sectional view of a backlight module of an electronic device according to an embodiment of the invention.

The electronic device of the present invention includes a backlight module 10, which is a direct-type backlight module. The backlight module 10 includes: a substrate 11; a plurality of light emitting diodes 13 disposed on the substrate 11, wherein the light emitting diodes 13 are blue light emitting diodes; a protective layer 14 disposed on the substrate 11 and covering the light emitting diode 13; and a light color conversion unit 24 disposed on the light emitting diode 13.

In addition, the backlight module 10 of the present embodiment may further include a reflective layer 12 disposed on the substrate 11 and between two adjacent light emitting diodes 13. The reflective layer 12 may be formed on the entire surface of the substrate 11, the reflective layer 12 is patterned to form a plurality of holes 121, and the light emitting diodes 13 are disposed in the holes 121. In the present embodiment, each led 13 is disposed corresponding to one of the holes 121; the invention is not limited thereto. In other embodiments of the present invention, one or more leds 13 may be disposed in one of the holes 121.

The substrate 11 may be a general substrate or a substrate including active devices. Typical substrates may include flexible or non-flexible substrates, and the material may include, for example, glass, quartz, wafers, sapphire, Polycarbonate (PC), Polyimide (PI), polypropylene (PP), polyethylene terephthalate (PET), other suitable materials, or combinations thereof. In addition, a circuit electrically connected to the led 13 may be formed on the substrate to drive the led 13. The substrate including the active device can be the substrate on which the active device is disposed, and the active device can drive the light emitting diode 13. An example of an active device may include a transistor.

The reflective layer 12 may comprise a material having reflectivity, such as white ink or a metal (e.g., silver, aluminum, gold, chromium, or alloys thereof).

The led 13 may be a bare die led or a packaged led. A bare-chip led is a light-emitting diode chip that includes electrodes (e.g., p-type and n-type electrodes), semiconductor layers, and a light-emitting layer without an encapsulation layer. A packaged led is a led chip that includes an encapsulation layer in addition to electrodes (e.g., p-type and n-type electrodes), a semiconductor layer, and a light-emitting layer. The light emitting diode 13 may be a blue light emitting diode. Here, the light emitting layer may include phosphor, quantum dot, or a combination thereof. In the present embodiment, the light emitting diode 13 is, for example, a bare-crystal light emitting diode.

Further, the light emitting diode 13 may be a multi-surface light emitting diode. In the present embodiment, the led chip can emit light except for the surface facing the substrate 11; in other words, the surface and the side surface of the led chip facing the passivation layer 14 can emit light. In the present embodiment, the light emitting diode 13 is a five-sided light emitting diode.

Furthermore, the led 13 may be a flip-chip led, and the led 13 has an electrode electrically connected to the circuit or the active device on the substrate 11.

The protective layer 14 may cover the light emitting diode 13. In the present embodiment, the protective layer 14 directly contacts the light emitting diode 13 to protect the light emitting diode 13. In addition, the protective layer 14 may also provide at least a portion of an optical distance (optical distance). The so-called optical distance will be described later. Herein, the material of the passivation layer 14 may include an optical glue, a silicon gel, a translucent glue or a combination thereof, and the diffusion particles may be selectively added in the material. In addition, the refractive index (n) of the protective layer 14 may be between 1.4 and 1.6 (1.4. ltoreq. n.ltoreq.1.6).

The backlight module 10 of the present embodiment may further include: a first brightness enhancement film 21, a diffusion film 22, and a second brightness enhancement film 23 disposed on the light color conversion unit 24, wherein the diffusion film 22 is disposed between the first brightness enhancement film 21 and the second brightness enhancement film 23. Here, the first brightness enhancement film 21 and the second brightness enhancement film 23 are prism optical films for enhancing the brightness of the backlight module, respectively, and the diffusion film 22 can make the light sources of the backlight module be uniformly distributed.

The light color conversion unit 24 is a unit capable of converting blue light into white light. In the present embodiment, the light color conversion unit 24 may be, for example, a light color conversion film, which may include phosphor, quantum dot, Dye (Dye), or a combination thereof.

The backlight module 10 of the present embodiment may further include: a light recycling layer 25, wherein the light recycling layer 25 is disposed on the protection layer 14, and the light color conversion unit 24 is disposed on the light recycling layer 25. The light recycling layer 25 is a multi-layer film formed by alternately stacking films with different refractive indexes. Wherein, the light transmittance (T1) of the light recycling layer 25 between 420nm and 480nm can be more than 75% (T1 > 75), and the light transmittance (T2) of the light recycling layer 25 between 550nm and 750nm can be less than 10% (T2 < 10%). In another embodiment of the present invention, the light recycling layer 25 may have an average light transmittance (T1) between 420nm and 480nm of more than 85% (T1 > 85%), and the light recycling layer 25 may have an average light transmittance (T2) between 550nm and 750nm of less than 3% (T2 < 3%).

In the backlight module without the light recycling layer 25, when the blue light emitted by the light emitting diode 13 is converted into the white light by the light color conversion unit 24, the generated red light and green light are scattered or reflected, thereby reducing the white light conversion efficiency and the light utilization rate.

In the backlight module of the present embodiment, the light recycling layer 25 has a high transmittance in the wavelength range between 420nm and 480nm, so that the wavelength band between 420nm and 480nm in the blue light band emitted by the light emitting diode 13 can pass through the light recycling layer 25 and pass through the light color conversion unit 24. Even if part of the blue light is reflected by the first brightness enhancement film 21, the diffusion film 22 or the second brightness enhancement film 23, the reflected blue light can be reflected back through the reflective layer 12 of the substrate 11 and pass through the layers above the reflective layer 12. In addition, the light recycling layer 25 has a low transmittance in the wavelength range between 550nm and 750nm, so most of the red light and green light emitted toward the light recycling layer 25 after being converted by the light color conversion unit 24 will be reflected by the light recycling layer 25 and pass through the layers above the light recycling layer 25. Therefore, the light recycling layer 25 can reduce the scattering of light to improve the utilization rate of the light emitted from the light emitting diode 13, so that the light emitting efficiency can be improved by about 50% or more.

In addition, in the backlight module 10 of the present embodiment, a distance OD is provided between the surface 122 of the reflective layer 12 and the light color conversion unit 24; more specifically, a distance OD is provided between the upper surface 122 of the reflective layer 12 and the upper surface 241 of the light color conversion unit 24. The distance OD is the optical distance. In addition, a space P is formed between two adjacent light emitting diodes 13; more specifically, the center points of two adjacent leds 13 have a pitch P. Wherein, the ratio of the distance OD to the distance P is more than 0.09 and less than 0.38 (OD/P is more than 0.09 and less than 0.38). In another embodiment of the present invention, the ratio of the distance OD to the pitch P may be greater than 0.17 and less than 0.38(0.17 < OD/P < 0.38). In another embodiment of the present invention, the ratio of the distance OD to the pitch P may be greater than 0.09 and less than 0.17(0.09 < OD/P < 0.17). When the ratio of the distance OD to the pitch P is smaller, it means that the overall thickness of the backlight module 10 is thinner, or the number of the light emitting diodes 13 used is smaller.

Furthermore, the backlight module 10 of the present embodiment is disposed in a frame 3 and emits light upward (as shown by the arrow). Although not shown, the electronic device of the present embodiment may further include a display panel disposed on the backlight module 10, and light (as shown by arrows) emitted from the backlight module 10 can pass through the display panel, so that the electronic device achieves the display effect.

Fig. 2 is a schematic cross-sectional view of a backlight module of an electronic device according to another embodiment of the invention. The same or similar elements in fig. 2 as those in fig. 1 will be given the same or similar reference numerals, and their detailed description will be omitted. The backlight module of fig. 2 is similar to that of fig. 1 except for the following differences.

The backlight module 10 of fig. 2 does not include the light recycling layer 25 of fig. 1. In addition, no diffuser film 22 (as shown in fig. 1) is disposed between the first brightness enhancement film 21 and the second brightness enhancement film 23 of fig. 2, and a microstructure array optical film 27 is disposed.

As shown in fig. 2, the backlight module 10 of the present embodiment further includes a microstructure array optical film 27 disposed on the protective layer 14, and the microstructure array optical film 27 is disposed between the first brightness enhancement film 21 and the second brightness enhancement film 23. Next, the structure of several kinds of the microstructure array optical film 27 will be given.

FIG. 3A is a schematic representation of an embodiment of the present inventionA perspective view of an example microstructure array optical film, and fig. 3B is a cross-sectional view of the microstructure array optical film of fig. 3A. As shown in fig. 2 and fig. 3A, the microstructure array optical film 27 of the present embodiment has an upper surface 271 and a lower surface 272, the upper surface 271 is opposite to the lower surface 272, and the lower surface 272 faces the protective layer 14, wherein the upper surface 271 is provided with a plurality of polyhedral grooves 273, and the polyhedral grooves 273 are arranged in an array. More specifically, the array is arranged in a repeating pattern in which two-dimensional or three-dimensional structures are regularly arranged along a specific direction, for example, in fig. 3A, the polyhedral cavities 273 are regularly arranged along the X direction and the Y direction. In FIG. 3A, the polyhedral recess 273 is a regular tetrahedron recess, also referred to as an inverted pyramid recess. As shown in FIGS. 3A and 3B, the width W of the polyhedral grooves 273_ACan be respectively between 50 μm and 180 μm (50 μm & lt W)_ALess than or equal to 180 μm) and the depth D of the polyhedral grooves 273_ACan be respectively between 10 μm and 50 μm (10 μm ≦ D)_ALess than or equal to 50 mu m). In more detail, the width W of the polyhedral grooves 273_AMay be the maximum width, depth D of the polyhedral recess 273_AMay be the maximum depth and may be defined as the distance from the height of the upper surface 271 of the microstructure array optical film 27 to the height of the end 273a of the polyhedron recess. In addition, in the present embodiment, the lower surface 272 is a plane.

Fig. 4A is a schematic perspective view of a microstructure array optical film according to an embodiment of the invention, and fig. 4B is a schematic cross-sectional view of the microstructure array optical film of fig. 4A. The microstructured array optical film of FIGS. 4A and 4B is similar to the microstructured array optical film of FIGS. 3A and 3B, except for lower surface 272; therefore, the structure of the upper surface 271 of the microstructure array optical film shown in fig. 4A and 4B will not be described again.

As shown in fig. 4B, the lower surface 272 of the optical film with a microstructure array of the present embodiment is provided with a plurality of pillar-shaped protrusions 274, and the pillar-shaped protrusions 274 are arranged in a staggered manner. More specifically, the columnar protrusions 274 extend along two different directions and are staggered with each other, and a concave portion 275 is formed between adjacent columnar protrusions 274, and the formed concave portions 275 are also arranged in an array. As shown in FIGS. 4A and 4B, the columnar protrusions 274 have a width W_BCan be between 35 μm and 115 μm (35 μm. ltoreq. W)_B115 μm or less), more specifically, the width W_BThe maximum width of the columnar protrusion 247 may be defined as the distance between two adjacent end points 275a of the concave portion, and the depth D of the concave portion 275_BCan be between 1 μm and 30 μm (1 μm. ltoreq. DB. ltoreq.30 μm), more particularly the depth D_BMay be the maximum depth of the recess 275, or may be defined as the distance between the height of a recess end 275a to the height of a raised cylindrical apex 274 a.

In addition, although not shown, another microstructure array optical film suitable for the present invention may have a plurality of polyhedral cavities 273 on both the upper surface 271 and the lower surface 272 as shown in fig. 3A and 3B. When the lower surface 272 is also provided with polyhedral grooves, the structural features of the polyhedral grooves of the lower surface 272 are similar to the structural features of the polyhedral grooves 273 of the upper surface 271 shown in fig. 3A and 3B, and therefore, the description thereof is omitted.

In the backlight module without the microstructure array optical film 27, in order to achieve the required visual effect, the spacing between the light emitting diodes 13 is often required to be reduced, and a larger number of light emitting diodes 13 are required, which results in an increase in the cost of the backlight module. Alternatively, the prism optical film needs to be added, but the brightness of the backlight module is reduced.

As shown in fig. 2, when the backlight module 10 includes the microstructure array optical film 27 having the aforementioned structure, the backlight uniformity of the backlight module 10 can be improved by the microstructures. In addition to this, the arrangement density of the light emitting diodes 13 per unit area can be reduced by providing the microstructure array optical film 27. Therefore, the pitch P between two adjacent light emitting diodes 13 is larger, so that the number of light emitting diodes 13 used is smaller, and the ratio (OD/P) of the distance OD from the surface 122 of the reflective layer 12 to the light color conversion unit 24 to the pitch P between two adjacent light emitting diodes 13 is further reduced. Meanwhile, the manufacturing cost of the backlight module can be further reduced because the number of the used light emitting diodes 13 is less.

Fig. 5 is a schematic cross-sectional view of a backlight module of an electronic device according to another embodiment of the invention. The same or similar elements in fig. 5 as those in fig. 1 and 2 will be denoted by the same or similar reference numerals, and their detailed description will be omitted. The backlight module of fig. 5 is similar to that of fig. 2 except for the following differences.

The backlight module 10 of fig. 5 does not include the second brightness enhancement film 23 of fig. 2. Since the backlight module 10 of fig. 5 has the brightness enhancement film 21 but less brightness enhancement film, the thickness of the backlight module 10 can be reduced, and the optical brightness of the backlight module 10 can be effectively improved compared to the backlight module without the brightness enhancement film.

Fig. 6 is a schematic cross-sectional view of a backlight module of an electronic device according to still another embodiment of the invention. The same or similar elements in fig. 6 as those in fig. 1 and 2 will be denoted by the same or similar reference numerals, and their detailed description will be omitted. The backlight module of fig. 6 is similar to that of fig. 5 except for the following differences.

The backlight module 10 of FIG. 6 has the brightness enhancement film 21 but has another less brightness enhancement film, and further includes a light recycling layer 25, wherein the light recycling layer 25 is disposed on the passivation layer 14, and the light color conversion unit 24 is disposed on the light recycling layer 25. Here, the structure and features of the light recycling layer 25 are as described above and will not be described in detail.

In the backlight module 10 of fig. 6, the light recycling layer 25 and the microstructure array optical film 27 are disposed at the same time, so that the light scattering can be reduced to improve the utilization rate of light, and the backlight uniformity of the backlight module 10 can be improved, and the arrangement density of the light emitting diodes 13 and the power consumption can be reduced.

Particularly, compared to the conventional backlight module, the number of the light emitting diodes 13 required by the backlight module 10 of fig. 6 can be reduced to about 40%, the light utilization rate of the backlight module 10 can be increased to about 180%, and the power consumption of the backlight module 10 can be reduced to about 50%. Taking the 6-hour backlight module as an example, under the condition that the brightness of the module reaches 500 nit, about 4500-; under the driving condition of 2.6W, the brightness of the existing module structure is about 500 nits, but the brightness of the module structure of the invention can be improved to 900 nits, that is, under the same driving condition, the light utilization rate of the module structure of the invention is improved to about 180 percent compared with the existing module structure; under the condition of achieving a module brightness of 500 nits, the power consumption of the existing structure is about 2.6 watts (W), while the power consumption of the module structure of the invention can be reduced to about 1.3 watts (W). In addition, in the conventional backlight module, the ratio (OD/P) of the distance OD from the surface 122 of the reflective layer 12 to the light color conversion unit 24 and the distance P between two adjacent light emitting diodes 13 needs to be greater than 0.38 to achieve the required visual effect; however, in the backlight module 10 of fig. 6, the effect of improving the visual effect can be achieved when the OD/P is greater than 0.17.

Fig. 7 is a schematic cross-sectional view of a backlight module of an electronic device according to still another embodiment of the invention. The same or similar elements in fig. 7 as those in fig. 1 and 2 will be denoted by the same or similar reference numerals, and their detailed description will be omitted. The backlight module of fig. 7 is similar to that of fig. 6 except for the following differences.

In the backlight module 10 of fig. 7, the microstructure array optical film 27 is the microstructure array optical film 27 shown in fig. 3A and 3B, and the lower surface 272 thereof is a plane and is optionally provided with at least one reflection unit 276. The reflection unit 276 is disposed corresponding to one of the light emitting diodes 13, that is, the reflection unit 276 and the light emitting diode 13 at least partially overlap in a top view direction (direction Z). In the present embodiment, each reflection unit 276 corresponds to one light emitting diode 13; the invention is not limited thereto. In other embodiments of the present invention, a portion of the light emitting diodes 13 may be provided with the reflection unit 276, and another portion of the light emitting diodes 13 may not be provided with the reflection unit 276. In addition, the area (A1) of the reflection unit 276 is 50% to 150% of the area (A2) of the light-emitting surface 131 of the light-emitting diode 13, i.e. 50% to 150% of A1/A2.

The reflective element 276 may be coated, attached, evaporated, or otherwise formed on the lower surface 272. The reflective element 276 may comprise a material having reflectivity such as white ink or a metal (e.g., silver, aluminum, gold, chromium, or alloys thereof). The reflectivity of the reflection unit 276 may be between 75% and 99%. In another embodiment of the present invention, the reflectivity of the reflection unit 276 may be between 80% and 95%, and more specifically, the "reflectivity" in this embodiment refers to the percentage of the light intensity measured after the light source is reflected by the reflection unit 276 divided by the light intensity before the light source is reflected by the reflection unit 276. The light intensity in the present invention refers to a spectrum integral value of a light source (the light source may, for example, include display light or ambient light), and the light source may, for example, include visible light (for example, wavelength between 380nm and 780 nm) or ultraviolet light (for example, wavelength less than 365nm), but is not limited thereto.

When the lower surface 272 of the micro-structure array optical film 27 is further provided with the reflection unit 276, the optical utilization rate can be further improved, and the brightness or the uniformity of the backlight module can be further improved.

In other embodiments of the present invention, the light color conversion unit 24 may be integrated with the protection layer 14. More specifically, the light color conversion unit 24 is a phosphor, a quantum dot or a combination thereof capable of converting blue light into red light and green light, and is added into the optical glue or the silica gel of the protection layer 14. Thereby, the thickness of the backlight module 10 can be further reduced.

In the present invention, the arrangement order of the light color conversion unit 24 and the microstructure array optical film 27 is not particularly limited. For example, in the backlight module 10 of fig. 2, 5 to 7, the microstructure array optical film 27 is disposed on the light color conversion unit 24; however, in another embodiment of the present invention, the light color conversion unit 24 may be disposed on the microstructure array optical film 27.

In the present invention, the number of the microstructure array optical film 27 used is also not particularly limited. For example, in the backlight module 10 of fig. 2, 5 to 7, a plurality of microstructure array optical films 27 may be selectively used. When multiple microstructure array optical films 27 are used, the structure of each microstructure array optical film 27 may be the same or different depending on the design. In addition, the position of each microstructure array optical film 27 may be the same or different, and for example, may be respectively disposed on or under the light color conversion unit 24.

In summary, the electronic device provided by the present invention has a special backlight module structure, so as to achieve the purposes of reducing the light source (i.e. light emitting diode) arrangement density of the backlight module, reducing the manufacturing cost, increasing the light efficiency, reducing the power consumption, or increasing the visual effect.

In the present invention, features of the embodiments may be arbitrarily mixed and matched without departing from the spirit or conflict of the invention.

Although the present invention has been described by way of examples, it is to be understood that many other modifications and variations are possible without departing from the spirit of the invention and the scope of the appended claims.

Furthermore, the above-mentioned embodiments are merely for illustrative purposes, and the scope of the claims of the present invention should not be limited to the above-mentioned embodiments.