阅读说明：本技术 前光显示器 (Front light display ) 是由 陈冠宇 李悦荣 范姜冠旭 蔡宪彰 于 2019-04-11 设计创作，主要内容包括：一种前光显示器,包括一光源、一耦合透镜、一第一与一第二偏振器、一导光板以及一反射显示器面板。导光板具有一第一表面、一第二表面、连接第一与第二表面的一侧表面以及位于第一与第二表面之间的导光微结构。第一偏振器、耦合透镜以及光源依序设置在侧表面的一侧处。发射不同颜色的光束的光源的发光元件沿着一第一方向而非一第二方向排列。第一方向平行于侧表面以及第一表面,且第二方向平行于侧表面并垂直于第一表面。耦合透镜包括沿着第一方向排列并分别沿着第二方向延伸的垂直柱状结构。(A front light display includes a light source, a coupling lens, a first polarizer, a second polarizer, a light guide plate and a reflective display panel. The light guide plate is provided with a first surface, a second surface, a side surface connecting the first surface and the second surface and a light guide microstructure positioned between the first surface and the second surface. The first polarizer, the coupling lens, and the light source are sequentially disposed at one side of the side surface. The light emitting elements of the light sources emitting light beams of different colors are arranged along a first direction but not a second direction. The first direction is parallel to the side surface and the first surface, and the second direction is parallel to the side surface and perpendicular to the first surface. The coupling lens includes vertical columnar structures arranged along a first direction and respectively extending along a second direction.)

1. A front light display, comprising:

a light source, suitable for outputting light beams with different colors;

a coupling lens disposed on a transmission path of the light beam from the light source;

a first polarizer disposed on a transmission path of the light beam from the coupling lens;

a light guide plate disposed on a transmission path of the light beam from the first polarizer, the light guide plate having a first surface, a second surface opposite to the first surface, a side surface connecting the first surface and the second surface, and a plurality of light guide microstructures between the first surface and the second surface, wherein the light beam from the first polarizer enters the light guide plate through the side surface;

a second polarizer disposed on the first surface of the light guide plate; and

a reflective display panel disposed below the second surface of the light guide plate,

wherein the light source comprises a plurality of light emitting elements, the plurality of light emitting elements emitting light beams of different colors are arranged along a first direction and not a second direction, the first direction is parallel to the side surface and the first surface, and the second direction is parallel to the side surface and perpendicular to the first surface; and

the coupling lens comprises a plurality of vertical columnar structures which are arranged along the first direction and respectively extend along the second direction.

2. The front light display of claim 1, wherein the plurality of light emitting elements are micro light emitting diodes and the plurality of light emitting elements emitting light beams of the same color are arranged along the second direction.

3. The front light display of claim 1, wherein the light emitting elements are light emitting diodes, the light emitting elements outputting light beams of different colors are alternately arranged along the first direction, and the number of the light emitting elements arranged along the second direction is only one.

4. The front light display of claim 1, wherein a plurality of the vertical columnar structures comprise a plurality of columnar prisms.

5. The front light display of claim 4, wherein each of the plurality of light emitting elements is disposed corresponding to a plurality of vertical pillar structures of the plurality of vertical pillar structures, and a pitch of the plurality of vertical pillar structures decreases as a distance from the corresponding light emitting element along the first direction increases.

6. The front light display of claim 4, wherein the plurality of columnar prisms comprises a plurality of non-isosceles columnar prisms.

7. The front light display of claim 1, wherein the coupling lens further comprises a plurality of horizontal pillar structures arranged along the second direction and respectively extending along the first direction, and the plurality of horizontal pillar structures overlap the plurality of vertical pillar structures along a third direction perpendicular to the first direction and the second direction.

8. The front light display of claim 1, wherein the light guide plate comprises a first portion and a second portion, the first portion being between the second portion and the second polarizer, the first portion and the second portion having a plurality of complementary cylindrical prisms at an interface therebetween, and the plurality of light guiding microstructures comprises the plurality of complementary cylindrical prisms.

9. The front light display of claim 8, wherein the first portion and the second portion have the same index of refraction.

10. The front light display of claim 1, wherein the reflective display panel is a liquid crystal on silicon display and the first polarizer and the second polarizer have opposite polarization directions.

11. The front light display of claim 1, wherein the front light display includes two light sources, two coupling lenses, and two first polarizers, each of the two coupling lenses disposed corresponding to one of the two light sources and each of the two first polarizers disposed corresponding to one of the two coupling lenses, the light guide plate has a plurality of side surfaces, and the two light sources are disposed corresponding to two opposite side surfaces of the plurality of side surfaces.

12. The front light display of claim 1, wherein the different colored light beams are different wavelength light beams or different color temperature light beams.

Technical Field

The present disclosure relates to displays, and particularly to a front light display.

Background

In a display equipped with a backlight module, the light uniformity of the backlight module is improved by providing a diffuser with light emitting elements of the same color placed in a horizontal manner or light emitting elements of different colors placed in a triangular manner. However, for front-view displays, a controllable light path is required to maintain polarization and small etendue. In the front light display, the above arrangement of the light emitting elements not only increases the etendue in the horizontal direction and makes the light path control design more difficult, but also causes a problem of color unevenness. In addition, the diffuser not only scatters the light beam from the light source, destroying the polarization direction, resulting in a reduction in light efficiency and contrast, but also expands the etendue in the horizontal direction and makes the light path control design more difficult.

Disclosure of Invention

The present invention provides a front light display having good light uniformity, light efficiency and contrast.

An embodiment of the invention provides a front light display, which includes a light source, a coupling lens, a first polarizer, a light guide plate, a second polarizer and a reflective display panel. The light source is adapted to output light beams of different colors. The coupling lens is disposed on a transmission path of the light beam from the light source. The first polarizer is disposed on a transmission path of the light beam from the coupling lens. The light guide plate is disposed on a transmission path of the light beam from the first polarizer. The light guide plate has a first surface, a second surface opposite to the first surface, a side surface connecting the first surface and the second surface, and a plurality of light guide microstructures between the first surface and the second surface, wherein the light beam from the first polarizer enters the light guide plate through the side surface. The second polarizer is disposed on the first surface of the light guide plate. The reflective display panel is disposed below the second surface of the light guide plate. The light source comprises a plurality of light-emitting elements, and the light-emitting elements emitting light beams of different colors are arranged along a first direction but not a second direction. The first direction is parallel to the side surface and the first surface, and the second direction is parallel to the side surface and perpendicular to the first surface. The coupling lens includes a plurality of vertical columnar structures arranged along a first direction and respectively extending along a second direction.

In view of the above, in the front light display according to the embodiment of the present invention, since the light emitting elements emitting light beams of different colors are arranged in the first direction (vertical direction) instead of the second direction (horizontal direction), a small etendue is achieved in the horizontal direction, and the light path control design is less difficult. In addition, by placing the vertical pillar structure in front of the light emitting device instead of the diffuser, the light uniformity in the horizontal direction is improved, and thus the light uniformity is improved without increasing the light collection rate in the horizontal direction and the difficulty of the light path control design, and the light efficiency and the contrast are not reduced. Therefore, the front light display according to the embodiment of the present invention has good light uniformity, light efficiency, and contrast ratio.

In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.

Drawings

Fig. 1 is a schematic cross-sectional view of a front light display according to an embodiment of the present invention.

Fig. 2A and 2B show two schematic front views of two embodiments of the light source in fig. 1, respectively.

Fig. 3 is a partial schematic cross-sectional view of the light source and coupling lens of fig. 1.

Fig. 4 and 5 are schematic top views of a front light display and a front light display according to an embodiment of the invention.

Fig. 6 is a partial schematic cross-sectional view of a front light display according to another embodiment of the present invention.

Fig. 7 is a partial schematic cross-sectional view of the light source and coupling lens of fig. 6.

Fig. 8 to 10 are schematic top views of front light displays according to other embodiments of the present invention, respectively.

The reference numbers are as follows:

1. 1A, 2, 3, 4, 5: front light display

10: light source

11. 11A: coupling lens

12: first polarizer

13: light guide plate

14: second polarizer

15: reflective display panel

100. 101, 102: light emitting element

103: circuit board

110: vertical columnar structure

111: transparent substrate

112: horizontal columnar structure

130: first surface

131: second surface

132. 132A, 134A: side surface

133: light guide microstructure

BB: blue light beam

BR: red light beam

BG. BG1, BG 2: green light beam

D. DA: distance between two adjacent plates

D1: a first direction

D2: second direction

D3: third direction

IRB, IRG, IRR: irradiation range

P, PA: pitch of

P1: the first part

P2: the second part

P11, P22: convex part

P12, P21: concave part

W, W': width of

Detailed Description

Fig. 1 is a schematic cross-sectional view of a front light display 1 according to an embodiment of the present invention. Referring to fig. 1, a front light display 1 includes a light source 10, a coupling lens 11, a first polarizer 12, a light guide plate 13, a second polarizer 14, and a reflective display panel 15.

The light source 10 is adapted to output light beams with different colors, such as a red light beam, a green light beam (the green light beams BG1 and BG2 are schematically shown in fig. 1), and a blue light beam, but the color of the light beam output by the light source 10 is not limited thereto. The coupling lens 11 is disposed on a transmission path of the light beam from the light source 10. The first polarizer 12 is disposed on a transmission path of the light beam from the coupling lens 11. The light guide plate 13 is disposed on a transmission path of the light beam from the first polarizer 12. The light guide plate 13 has a first surface 130, a second surface 131 opposite to the first surface 130, a side surface 132 connecting the first surface 130 and the second surface 131, and a plurality of light guide microstructures 133 located between the first surface 130 and the second surface 131, wherein the light beam from the first polarizer 12 enters the light guide plate 13 through the side surface 132. The second polarizer 14 is disposed on the first surface 130 of the light guide plate 13. The reflective display panel 15 is disposed under the second surface 131 of the light guide plate 13.

Fig. 2A and 2B show two schematic front views of two embodiments of the light source 10 in fig. 1, respectively. Referring to fig. 1 to 2B, the light source 10 includes a plurality of light emitting elements, for example, a plurality of light emitting elements 100 capable of outputting red light beams, a plurality of light emitting elements 101 capable of outputting green light beams, and a plurality of light emitting elements 102 capable of outputting blue light beams. In other words, the light-emitting elements 100, 101, and 102 are red, green, and blue light-emitting elements, respectively. However, in other embodiments, the light source 10 may include a plurality of light emitting elements capable of outputting light beams of other colors.

The light emitting elements (e.g., the light emitting elements 100, 101, 102) may be micro light emitting diodes or light emitting diodes, but not limited thereto. A light source 10 that produces different colored light beams using light emitting elements (e.g., micro-leds or leds) has a better color gamut than a light source that produces different colored light beams using phosphors. In addition, the light source 10 may use micro light emitting diodes as light emitting elements to shorten a light mixing distance (a distance required to mix light of different colors into white light) of the light emitting elements. On the other hand, the light source 10 may use light emitting diodes as light emitting elements to reduce the number of light emitting elements required for the light source 10 and simplify circuit design.

The light emitting elements (e.g., light emitting elements 100, 101, 102) emitting light beams of different colors are arranged along a first direction D1 instead of a second direction D2. The first direction D1 is parallel to the side surface 132 and the first surface 130; herein, the first direction D1 may be referred to as a horizontal direction. On the other hand, the second direction D2 is parallel to the side surface 132 but perpendicular to the first surface 130; here, the second direction D2 may be referred to as a vertical direction. In other words, the light emitting elements that emit light beams of different colors are not arranged along the second direction D2 (vertical direction). Since the light emitting elements emitting light beams of different colors are arranged along the first direction D1 (horizontal direction) instead of the second direction D2 (vertical direction), a small etendue of the light beams of different colors is maintained in the horizontal direction, and the light path control design is less difficult.

As shown in fig. 2A, the light emitting elements (e.g., the light emitting elements 100, 101, 102) may be micro light emitting diodes, and the light emitting elements emitting light beams of different colors may be alternately arranged along the first direction D1. Further, the light emitting elements emitting light beams of the same color may be arranged along the second direction D2 such that the number of light emitting elements arranged along the second direction D2 is more than one.

As shown in fig. 2B, the light emitting elements (e.g., the light emitting elements 100, 101, 102) may be light emitting diodes, such as light emitting diode chips or light emitting diode packages, and the light emitting elements emitting light beams of different colors may be alternately arranged along the first direction D1. Further, the shape of each light emitting element may be rectangular, and the long axis of each light emitting element may extend along the second direction D2. As such, the number of light emitting elements arranged along the second direction D2 may be only one. Alternatively, the number of the light emitting elements arranged along the second direction D2 may be more than one.

The light source 10 may further include other elements as desired. For example, the light source 10 may further include a circuit board 103 for carrying the light emitting elements and signal transmission. In other embodiments, a controller (not shown) for controlling the on or off state of the light emitting element may also be provided on the circuit board 103.

A coupling lens 11 is located between the light source 10 and the first polarizer 12. Fig. 3 is a partial schematic cross-sectional view of the light source 10 and the coupling lens 11 in fig. 1. Referring to fig. 1 and 3, the coupling lens 11 includes a plurality of vertical pillar structures 110 arranged along a first direction D1 and respectively extending along a second direction D2.

The vertical columnar structure 110 of the coupling lens 11 is adapted to expand the irradiation range of each color light beam (for example, the red light beam BR, the green light beam BG, and the blue light beam BB) along the first direction D1. For example, the vertical pillar structures 110 may include a plurality of pillar prisms (or called triangular pillars). Further, the prism may include a plurality of non-isosceles prism prisms. Specifically, the cross-sectional shapes of at least some of the prisms on the reference plane formed by the first direction D1 and the third direction D3 are not isosceles triangles, wherein the third direction D3 is perpendicular to the first direction D1 and the second direction D2. The vertical pillar structures 110 may be formed on a transparent substrate (e.g., a glass substrate) 111 through heating or irradiating an optical paste cured by light. Furthermore, each of the light emitting elements (e.g., the light emitting elements 100, 101, 102) is disposed corresponding to (more than one) of the vertical pillar structures 110, and the pitch P of the vertical pillar structures 110 decreases as the distance D from the corresponding light emitting element along the first direction D1 increases. In this way, a light beam having a large angle can be guided to the light guide plate 13 (refer to fig. 1), and thus the irradiation range of the light beam of each color along the first direction D1 is expanded.

Note that fig. 3 schematically shows an example of the vertical columnar structure 110 and a relative arrangement relationship between the light emitting element and the vertical columnar structure 110; however, the number, arrangement, shape, and manufacturing method of the vertical columnar structures 110 and the relative arrangement relationship between the light emitting elements and the vertical columnar structures 110 are not limited to those shown in fig. 3 and described above.

FIGS. 4 and 5 are schematic top views of a front light display 2 and a front light display 1 according to an embodiment of the present invention, respectively, wherein the difference between the front light display 2 and the front light display 1 is that the front light display 2 does not include the coupling lens 11 in the front light display 1 according to the embodiment

In fig. 4 and 5, in order to facilitate recognition of the light beams of different colors, red light beam BR and its irradiation range IRR are indicated by thick solid lines, green light beam BG and its irradiation range IRG are indicated by thin solid lines, and blue light beam BB and its irradiation range IRB are indicated by thin broken lines.

As can be seen from fig. 4 and 5, the width W' of each illumination range IRR, IRG and IRB along the first direction D1 in the front light display 1 according to the present embodiment is greater than the width W of each illumination range IRR, IRG and IRB along the first direction D1 in the compared front light display 2. Since the irradiation ranges of the light beams of different colors overlap along the first direction D1, the uniformity of light in the first direction D1 (horizontal direction) is improved. In addition, since the uniformity of light in the horizontal direction is improved by placing the vertical pillar structures 110 in front of the light emitting elements instead of the diffuser, the uniformity of light is improved without increasing the etendue in the vertical direction, so that the light path control design is less difficult and the light efficiency and contrast can be maintained. Therefore, the front light display 1 may have good light uniformity, light efficiency, and contrast ratio.

Referring to fig. 1 again, the light guide plate 13 is disposed between the second polarizer 14 and the reflective display panel 15, and a side surface 132 of the light guide plate 13 faces the first polarizer 12. The light guiding microstructures 133 within the light guiding plate 13 are adapted to guide light beams to the reflective display panel 15 and allow light beams from the reflective display panel 15 to pass through. Note that fig. 1 schematically shows an example of the light guide plate 13 and its light guide microstructures 133; however, the number, arrangement, and shape of the light guide plate 13 and the light guide microstructures 133 thereof are not limited to those shown in fig. 1.

As shown in fig. 1, the light guide plate 13 includes a first portion P1 and a second portion P2, wherein the first portion P1 is located between the second portion P2 and the second polarizer 14. The first portion P1 and the second portion P2 have complementary cylindrical prisms at the interface therebetween, and the light guiding microstructures 133 include the complementary cylindrical prisms. Specifically, the first portion P1 has a plurality of protrusions P11 and a plurality of recesses P12 alternately arranged in the third direction D3, and the second portion P2 has a plurality of recesses P21 and a plurality of protrusions P22 alternately arranged in the third direction D3, wherein the protrusions P11 of the first portion P1 and the recesses P21 of the second portion P2 are complementary in shape and connected together, and the recesses P12 of the first portion P1 and the protrusions P22 of the second portion P2 are complementary in shape and connected together. The convex portion P11, the concave portion P12, the concave portion P21, and the convex portion P22 form complementary columnar prisms. In addition, the first portion P1 has the same refractive index as the second portion P2 to avoid ghost images. To achieve the PBS effect (to reflect S-polarized light and allow P-polarized light to pass through), a multilayer coating may be formed at the interface between the first portion P1 and the second portion P2.

The reflective display panel 15 is disposed on a transmission path of the light beam from the light guide plate 13 to convert the light beam (irradiation light beam) from the light guide plate 13 into an image light beam. For example, the reflective display panel 15 is a liquid crystal on silicon display, but not limited thereto.

The first polarizer 12 and the second polarizer 14 have opposite polarization directions. For example, first polarizer 12 is adapted to allow the s-polarized light beam to pass through and filter (e.g., absorb) the p-polarized light beam, while second polarizer 14 is adapted to allow the p-polarized light beam to pass through and filter (e.g., absorb) the s-polarized light beam. The reflective display panel 15 converts the s-polarized light beam into the p-polarized light beam, and reflects the p-polarized light beam back to the light guide plate 13, and outputs the p-polarized light beam from the front light display 1 after sequentially passing through the light guide plate 13 and the second polarizer 14.

Fig. 6 is a partial schematic cross-sectional view of a front light display 1A according to another embodiment of the present invention. Fig. 7 is a partial schematic cross-sectional view of the light source 10 and the coupling lens 11A in fig. 6. Referring to fig. 6 and 7, a main difference between the front light display 1A and the front light display 1 of fig. 1 is that a coupling lens 11A of the front light display 1A is different from a coupling lens 11 of the front light display 1 of fig. 1.

Specifically, the coupling lens 11A further includes a plurality of horizontal columnar structures 112 arranged along the second direction D2 and extending along the first direction D1, respectively, and the horizontal columnar structures 112 and the vertical columnar structures 110 overlap along the third direction D3. For example, the horizontal pillar structures 112 and the vertical pillar structures 110 are formed on the transparent substrate 111 by sequentially curing optical glues with different refractive indexes by heating or irradiating light. However, the relative arrangement relationship, the manufacturing order, and the manufacturing method of the horizontal columnar structures 112 and the vertical columnar structures 110 are not limited to those shown in fig. 6 and 7 and described above. In other embodiments, the vertical pillar structures 110 may be formed before the horizontal pillar structures 112 are formed. In addition, the horizontal pillar structures 112 and the vertical pillar structures 110 may be formed on two opposite surfaces of the transparent substrate 111, respectively. Alternatively, the horizontal pillar structures 112 and the vertical pillar structures 110 may be formed on two transparent substrates.

The horizontal columnar structure 112 is adapted to expand the irradiation range of the light beam of each color (red light beam BR exemplarily shown in fig. 6) along the second direction D2 and allow more light beams to be transmitted to the side of the light guide plate 13 away from the side surface 132. For example, the horizontal pillar structures 112 may take the same state as the vertical pillar structures 110 shown in fig. 3; however, the arrangement direction and the extending direction between the horizontal pillar structures 112 and the vertical pillar structures 110 are opposite. In other embodiments, the horizontal pillar structures 112 may adopt a different state than the vertical pillar structures 110.

Fig. 6 schematically shows that the number of light-emitting elements (e.g., light-emitting elements 100) that emit light beams of the same color (e.g., red light beams BR) arranged in the second direction D2 is three, wherein each of the light-emitting elements is disposed corresponding to a plurality (more than one) of the horizontal columnar structures 112, and the pitch PA of the plurality of horizontal columnar structures 112 decreases as the distance DA from the corresponding light-emitting element along the second direction D2 increases. However, the number, arrangement, shape, and manufacturing method of the horizontal columnar structures 112 and the relative arrangement relationship between the light emitting elements and the horizontal columnar structures 112 are not limited to those shown in fig. 6 and 7 and described above.

Fig. 8 to 10 are schematic top views of front light displays 3, 4 and 5, respectively, according to other embodiments of the present invention. Referring to fig. 8, a main difference between the front light display 3 and the front light display 1 of fig. 5 is the relative arrangement relationship of the light source 10, the coupling lens 11 and the first polarizer 12 with respect to the light guide plate 13. Specifically, as shown in fig. 8, the light guide plate 13 has two short side surfaces (side surfaces 132 and 132A) and two long side surfaces (side surfaces 134 and 134A). In fig. 5, the light source 10, the coupling lens 11, and the first polarizer 12 are disposed at one of short side surfaces (e.g., the side surface 132) of the light guide plate 13, and in fig. 8, the light source 10, the coupling lens 11, and the first polarizer 12 are disposed at one of long side surfaces (e.g., the side surface 134) of the light guide plate 13.

Referring to fig. 9, the main differences between the front light display 4 and the front light display 1 of fig. 5 are as follows. The front light display 4 comprises two light sources 10, two coupling lenses 11 and two first polarizers 12. Each of the two coupling lenses 11 is disposed corresponding to one of the two light sources 10, and each of the two first polarizers 12 is disposed corresponding to one of the two coupling lenses 11. The light guide plate 13 has a plurality of side surfaces 132, 132A, 134 and 134A, and two light sources 10 are disposed corresponding to two opposite side surfaces (e.g., the side surfaces 132 and 132A) among the side surfaces 132, 132A, 134 and 134A.

Referring to fig. 10, the main differences between the front light display 5 and the front light display 4 of fig. 9 are as follows. In fig. 9, two light sources 10, two coupling lenses 11, and two first polarizers 12 are disposed at short side surfaces (side surfaces 132 and 132A) of the light guide plate 13, whereas in fig. 10, two light sources 10, two coupling lenses 11, and two first polarizers 12 are disposed at long side surfaces (side surfaces 134 and 134A) of the light guide plate 13.

In summary, in the front light display according to the embodiment of the invention, since the light emitting elements emitting light beams of different colors are arranged along the first direction (vertical direction) instead of the second direction (horizontal direction), a small etendue is achieved in the horizontal direction, and the light path control design is less difficult. In addition, by placing the vertical pillar structure in front of the light emitting device instead of the diffuser, the light uniformity in the horizontal direction is improved, and thus the light uniformity is improved without increasing the light collection rate in the horizontal direction and the difficulty of the light path control design, and the light efficiency and the contrast are not reduced. Therefore, the front light display according to the embodiment of the present invention has good light uniformity, light efficiency, and contrast ratio. In one embodiment, light uniformity in the vertical direction can be improved by further placing horizontal pillar structures in front of the light emitting elements. In another embodiment, a front light display may have two light sources, two coupling lenses, and two first polarizers disposed at opposite side surfaces of a light guide plate.

Although the present invention has been described with reference to the above embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention.