CN108693591B

CN108693591B - Light guide assembly

Info

Publication number: CN108693591B
Application number: CN201710222786.5A
Authority: CN
Inventors: 施耀淙; 张梅桢; 鲍友南; 黄信道
Original assignee: Yuan Tai Technology Industry Co ltd
Current assignee: Yuan Tai Technology Industry Co ltd
Priority date: 2017-04-07
Filing date: 2017-04-07
Publication date: 2021-08-27
Anticipated expiration: 2037-04-07
Also published as: CN108693591A

Abstract

The invention discloses a light guide assembly, which comprises at least one light source and a light guide plate. The light guide plate is provided with at least one microstructure area, a light incident surface, a front surface and a back surface which are opposite. The light incident surface is located between the front surface and the back surface and is adjacent to the front surface and the back surface. The microstructure area is located on the front side or the back side. The microstructure area is close to the light incident surface. The microstructure area is aligned with the light source. The microstructure area has a plurality of microstructures therein. The light source is located outside the light guide plate and faces the light incident surface of the light guide plate. Because the microstructure area is positioned on the front or the back of the light guide plate and corresponds to the light source, when the light source emits light, the microstructure area can destroy the total reflection of the light, so that the light is refracted in the microstructure area to emit light, a bright area is prevented from being generated in the area of the light guide plate right in front of the light source, the energy of each position is uniform when the light is transmitted to the visible area of the light guide plate, and the phenomenon of uneven light of a hot spot is reduced.

Description

Light guide assembly

Technical Field

The invention relates to a light guide assembly.

Background

In the lcd device, since the liquid crystal itself does not emit light, the backlight module is needed to provide the display light source. In addition, in the electronic paper display device, since the display medium layer needs to display an image by reflecting light, the front light module is usually configured to provide light, so that the electronic paper display device can still display normally when the ambient light source is insufficient. In either a backlight module of a liquid crystal display device or a front light module of an electronic paper display device, a plurality of point light sources, such as Light Emitting Diodes (LEDs), can be replaced with a surface light source by using a light guide plate.

Generally, when a point light source is used on one side of a light guide plate, the problem of uneven brightness in the visible region can be avoided unless the light guide plate has a sufficient light coupling region, but the volume of the light guide plate is difficult to be reduced. Or, microstructures with different densities can be manufactured on the light-emitting surface of the light guide plate close to the light source to achieve the effect of uniform brightness. However, if the display device has a plurality of independent loops for controlling a plurality of point light sources, the density distribution of the microstructure cannot be applied. For example, when two adjacent point light sources A, B are lit at different timings, only the light source a is lit, the microstructure should be designed to be sparse in the region immediately in front of the light source a and dense in the region immediately in front of the light source B. However, when only the light source B is turned on, the microstructure should be designed to be dense in the region immediately in front of the light source B and sparse in the region immediately in front of the light source a. As such, the microstructure distributions corresponding to the point light sources A, B will contradict each other.

Disclosure of Invention

An object of the present invention is to provide a light guide assembly that can prevent bright areas from being generated in a light guide plate area right in front of a light source, so that energy at each position is uniform when light is transmitted to a visible area of the light guide plate, and reduce uneven light at hot spots.

According to an embodiment of the present invention, a light guide assembly includes at least one light source and a light guide plate. The light guide plate is provided with at least one microstructure area, a light incident surface, a front surface and a back surface which are opposite. The light incident surface is located between the front surface and the back surface and is adjacent to the front surface and the back surface. The microstructure area is located on the front side or the back side. The microstructure area is close to the light incident surface. The microstructure area corresponds to the light source. The microstructure area has a plurality of microstructures therein. The light source is located outside the light guide plate and faces the light incident surface of the light guide plate.

In an embodiment of the invention, a distance between the microstructure region and the light incident surface of the light guide plate is in a range from 1mm to 5 mm.

In an embodiment of the invention, the profile of the microstructure is rectangular, circular, elliptical, triangular or trapezoidal.

In an embodiment of the invention, the microstructure in the microstructure area is a bump or a pit.

In an embodiment of the invention, the light guide assembly further includes a light adjusting element. When the microstructure area is positioned on the front surface of the light guide plate, the light adjusting element is positioned on the front surface and covers the microstructure area. When the microstructure area is positioned on the back surface of the light guide plate, the light adjusting element is positioned on the back surface and covers the structure area.

In an embodiment of the invention, the light adjusting element has a first edge and a second edge opposite to each other, and a distance between the first edge and the second edge is not less than a width of the microstructure region.

In one embodiment of the present invention, the optical adjusting element has an adhesive layer and a light absorbing layer, and the adhesive layer is located between the light absorbing layer and the light guide plate.

In an embodiment of the invention, the optical adjusting element has an adhesive layer and a light scattering layer, and the adhesive layer is located between the light scattering layer and the light guide plate.

In an embodiment of the invention, a difference between the refractive index of the adhesive layer and the refractive index of the light guide plate is in a range of 0.1 to 0.7.

In an embodiment of the invention, the light guide assembly further includes a cover. The cover body covers the microstructure area, the light source and the shielding area of the light guide plate.

In an embodiment of the invention, the microstructure area is located in a shielding area of the light guide plate.

In an embodiment of the invention, the light guide assembly has a plurality of light sources, and the light sources are electrically connected to at least two driving elements.

In an embodiment of the invention, the first portion of the light source has a first color temperature, the second portion of the light source has a second color temperature, and the first portion and the second portion of the light source are electrically connected to the two driving elements respectively.

In an embodiment of the invention, the first portion of the light source has a first color, the second portion of the light source has a second color, and the first portion and the second portion of the light source are respectively electrically connected to the two driving elements.

In the above embodiment of the invention, since the microstructure area is located on the front surface or the back surface of the light guide plate and corresponds to the light source, when the light source emits light, the microstructure area can destroy the total reflection of the light, so that the light is refracted in the microstructure area to emit light, thereby preventing a bright area from being generated in a region of the light guide plate in front of the light source. That is, the light guide plate reduces the energy of the area close to the light source through the design of the microstructure area, so that the energy of each position is uniform when the light is transmitted to the visible area of the light guide plate, and the phenomenon of hot spot light nonuniformity is reduced.

Drawings

Fig. 1 is a top view of a light guide assembly according to an embodiment of the invention.

FIG. 2 is a cross-sectional view of the light guide assembly of FIG. 1 taken along line 2-2.

FIG. 3 is a cross-sectional view of a light guide assembly according to an embodiment of the invention.

FIG. 4 is a cross-sectional view of a light guide assembly according to an embodiment of the invention.

Fig. 5 is a top view of a light guide assembly according to an embodiment of the invention.

FIG. 6 is a cross-sectional view of the light guide assembly of FIG. 5 taken along line 6-6.

FIG. 7 is a cross-sectional view of a light guide assembly according to an embodiment of the invention.

FIG. 8 is a cross-sectional view of a light guide assembly according to an embodiment of the invention.

FIG. 9 is a cross-sectional view of a light guide assembly according to an embodiment of the invention.

FIG. 10 is a top view of a light guide assembly according to an embodiment of the invention.

Fig. 11 is a top view of a light guide assembly according to an embodiment of the invention.

FIG. 12 is a top view of a light guide assembly according to an embodiment of the invention.

Fig. 13 is a top view of a light guide assembly according to an embodiment of the invention.

Detailed Description

In the following description of the embodiments of the present invention, reference is made to the accompanying drawings, which are provided for illustration purposes, and in which is shown by way of illustration some conventional structures and elements.

Fig. 1 is a top view of a light guide assembly 100 according to an embodiment of the invention. Fig. 2 is a cross-sectional view of the light guide assembly 100 of fig. 1 along line 2-2. Referring to fig. 1 and 2, the light guide assembly 100 includes a light guide plate 110 and

light sources

120a and 120 b. The light guide plate 110 has at least one microstructure region 111, a light incident surface 112, and a front surface 114 and a back surface 116 opposite to each other. The light incident surface 112 is located between the front surface 114 and the back surface 116 and is adjacent to the front surface 114 and the back surface 116. In the present embodiment, the microstructure region 111 is located on the back surface 116 of the light guide plate 110. However, in other embodiments, the microstructure region 111 may also be located on the front surface 114 of the light guide plate 110, and is not intended to limit the invention. The microstructure region 111 is close to the light incident surface 112 and substantially aligned with the

light sources

120a and 120 b. The microstructure region 111 has a plurality of microstructures therein for light to pass through. In the embodiment of the invention, the microstructure region 111 has a plurality of bumps as an example, but the invention is not limited thereto, and the microstructure region may also have a plurality of pits (not shown).

The

light sources

120a and 120b are located outside the light guide plate 110, and the

light sources

120a and 120b face the light incident surface 112 of the light guide plate 110. The

light sources

120a, 120b may be point light sources, such as Light Emitting Diodes (LEDs). The front surface 114 and the back surface 116 of the light guide plate 110 can be used as light emitting surfaces of the light guide plate 110. For example, when the light guide assembly 100 is applied to a liquid crystal display device, the light guide assembly 100 is a backlight module, and the front surface 114 of the light guide plate 110 is a light-emitting surface on which a liquid crystal display panel may be disposed. When the light guide assembly 100 is applied to an electronic paper display device, the light guide assembly 100 is a front light module, the back 116 of the light guide plate 110 is a light emitting surface, and an electronic paper display panel may be disposed below the light emitting surface.

When the

light sources

120a, 120b emit light, the microstructure area 111 is located on the light guide plate 110 and aligned with the

light sources

120a, 120b, so that the microstructure area 111 with microstructures can destroy the total reflection of the light, so that the light is refracted out of the microstructure area 111, thereby avoiding the generation of bright areas in the light guide plate 110 area right in front of the

light sources

120a, 120 b. For example, when the light L1 is transmitted to the microstructure region 111 of the back surface 116, the light L1 can be refracted at the microstructure region 111 to form the light L2, and no total reflection occurs in the light guide plate 110. The light guide plate 110 reduces the energy of the regions close to the

light sources

120a and 120b by the design of the microstructure region 111, so that the energy at each position is uniform when the light is transmitted to the visible region 117 of the light guide plate 110, and the hot spot light nonuniformity is reduced.

The distance d1 between the microstructure region 111 and the light incident surface 112 of the light guide plate 110 may be in the range of 1mm to 5mm, so that the microstructure region 111 can effectively destroy the total reflection in the region of the light guide plate 110 directly in front of the

light sources

120a and 120 b. In this embodiment, the profile of the microstructure in the microstructure region 111 is rectangular or square, but in other embodiments, the profile of the microstructure in the microstructure region 111 may also be circular, oval, triangular or trapezoidal, and is not limited to the invention.

In the present embodiment, the

light sources

120a and 120b are electrically connected to the

driving elements

102a and 102b, respectively, so that the

light sources

120a and 120b belong to different circuits and can be turned on or off by the driving

elements

102a and 102b, respectively. In fig. 1, the number of the light sources 120a is three, which can be regarded as a first portion of the light sources; the number of light sources 120b is two and can be considered as the second portion of the light sources. Light source 120a may have a first color temperature (e.g., 6000K) and light source 120b may have a second color temperature (e.g., 4000K). Alternatively, light source 120a may have a first color (e.g., red) and light source 120b may have a second color (e.g., blue). Since the positions of the microstructure regions 111 of the light guide plate 110 correspond to the positions of the

light sources

120a and 120b, light directly in front of each of the

light sources

120a and 120b can be refracted from the microstructure region 111 corresponding to the position. In this context, positional "correspondence" means substantially aligned. When the light source 120a is turned on and the light source 120b is turned off, the light directly in front of the light source 120a is refracted from the microstructure area 111 aligned with the light source 120a, and the light of the light source 120a is not affected by the microstructure area 111 aligned with the light source 120 b. When the light source 120b is turned on and the light source 120a is turned off, the light directly in front of the light source 120b is refracted from the microstructure area 111 aligned with the light source 120b, and the light of the light source 120b is not affected by the microstructure area 111 aligned with the light source 120 a.

It should be understood that the connection and function of the elements described above will not be repeated, and will be described in detail. In the following description, other forms of light guide assemblies will be described.

Fig. 3 is a cross-sectional view of a light guide assembly 100a according to an embodiment of the invention. The light guide assembly 100a includes a light guide plate 110a and a light source 120 a. The difference from the embodiment of fig. 2 is that: the microstructure region 111a of fig. 3 is located on the front surface 114a of the light guide plate 110 a. With such a design, the light guide assembly 100a can still have the effects of the light guide assembly 100 of fig. 1 and 2.

Fig. 4 is a cross-sectional view of a light guide assembly 100b according to an embodiment of the invention. The light guide assembly 100b includes a light guide plate 110 and a light source 120 a. The difference from the embodiment of fig. 2 is that: the light guide assembly 100b further includes a cover 140. The portion of the light guide plate 110 shielded by the cover 140 is a shielding region 118, and the portion not shielded by the cover 140 is a visible region 117. The cover 140 covers the light source 120a and the microstructure region 111 and the shielding region 118 of the light guide plate 110. In other words, the cover 140 overlaps the light source 120a, the shielding region 118 of the light guide plate 110, and the microstructure region 111. The microstructure region 111 of the light guide plate 110 is located in the shielding region 118. The microstructure regions 111 ensure uniform brightness when the light from the light source 120a is transmitted to the visible region 117 of the light guide plate 110.

Fig. 5 is a top view of a light guide assembly 100c according to an embodiment of the invention. FIG. 6 is a cross-sectional view of the light guide assembly 100c of FIG. 5 taken along line 6-6. For simplicity, the driving

elements

102a, 102b of fig. 1 will be omitted in fig. 5, 10 to 13. Referring to fig. 5 and 6, the light guide assembly 100c includes a light guide plate 110 and

light sources

120a and 120 b. The difference from the embodiment of fig. 1 and 2 is that: light guide assembly 100c also includes a light adjusting element 130. In the present embodiment, the microstructure region 111 is located on the back surface 116 of the light guide plate 110, and the light adjusting element 130 is located on the back surface 116 and covers the microstructure region 111. The light adjusting element 130 has an adhesive layer 136 and a light absorbing layer 138. The adhesive layer 136 is located between the light absorbing layer 138 and the back surface 116 of the light guide plate 110. The difference between the refractive index of the adhesive layer 136 and the refractive index of the light guide plate 110 may be in the range of 0.1 to 0.7. For example, since the refractive index of the light guide plate 110 is 1.58 and the refractive index of air is 1, when the refractive index of the adhesive layer 136 is 1.52, the critical angle of light can be further increased, so that light rays (e.g., light ray L3) smaller than the critical angle can be reflected through the light guide plate 110 to the adhesive layer 136 (e.g., light ray L4) and then absorbed by the light absorbing layer 138. In this embodiment, the light absorbing layer 138 may be a dark color (e.g., black) to aid in absorbing light.

The light adjusting element 130 and the microstructure region 111 can both destroy the total internal reflection of the high energy region of the light guide plate 110, and further make the brightness distribution of the light adjusting element 130 and the region of the light guide plate 110 on the right side of the microstructure region 111 (e.g. the visible region 117 not shielded by the cover) uniform. In addition, the light adjusting element 130 can prevent the light guide plate 110 from generating irregular bright lines due to the assembly tolerance of the

light sources

120a and 120b and the manufacturing tolerance of the microstructure region 111, and can solve the problem of light leakage caused by light penetrating through the microstructure region 111.

In the present embodiment, the length direction of the light adjusting element 130 is the same as the length direction of the light incident surface 112 of the light guide plate 110 (both directions D), and the length of the light adjusting element 130 is substantially the same as the width of the light guide plate 110. The light adjusting element 130 has a first edge 131 and a second edge 133 opposite to each other. The first edge 131 of the light adjusting element 130 is adjacent to the light incident surface 112 of the light guide plate 110, and the distance d2 between the first edge 131 and the second edge 133 is greater than or equal to the width of the microstructure region 111 and can cover the microstructure region 111, in one embodiment, the distance d2 is in the range of 3mm to 7mm, so that the light adjusting element 130 can not only destroy the total reflection of the high energy region of the light guide plate 110, but also avoid excessive absorption of light rays and influence on the overall brightness of the light guide plate 110.

Fig. 7 is a cross-sectional view of a light guide assembly 100d according to an embodiment of the invention. The light guide assembly 100d includes a light guide plate 110a and a light source 120 a. The difference from the embodiment of fig. 6 is that: the microstructure region 111a of the light guide plate 110a is located on the front surface 114a of the light guide plate 110a, and the light adjusting element 130 is located on the front surface 114a of the light guide plate 110a and covers the microstructure region 111 a. With such a design, the light guide assembly 100d can still have the functions of the light guide assembly 100c of fig. 5 and 6.

Fig. 8 is a cross-sectional view of a light guide assembly 100e according to an embodiment of the invention. The light guide assembly 100e includes a light guide plate 110, a light source 120a and a light adjusting element 130 a. The difference from the embodiment of fig. 6 is that: the light adjusting element 130a has an adhesive layer 136 and a light scattering layer 139, and the adhesive layer 136 is located between the light scattering layer 139 and the light guide plate 110. In this embodiment, the microstructure region 111 is located on the back surface 116 of the light guide plate 110, and the light adjusting element 130a is located on the back surface 116 and covers the microstructure region 111. The difference between the refractive index of the adhesive layer 136 and the refractive index of the light guide plate 110 may be in the range of 0.1 to 0.7. The adhesive layer 136 may further increase the critical angle of light in the light guide plate 110, so that light (e.g., light L5) smaller than the critical angle may be reflected through the light guide plate 110 to the adhesive layer 136 (e.g., forming light L6), and further scattered by the light scattering layer 139 to be atomized (e.g., forming a plurality of light L7), so that the brightness distribution of the light adjusting element 130a and the area of the light guide plate 110 on the right side of the microstructure region 111 is uniform. In this embodiment, the light diffusion layer 139 may be a light color (e.g., white) to help diffuse and atomize light.

Fig. 9 is a cross-sectional view of a light guide assembly 100f according to an embodiment of the invention. The light guide assembly 100f includes a light guide plate 110a and a light source 120 a. The difference from the embodiment of fig. 8 is that: the microstructure region 111a of the light guide plate 110a is located on the front surface 114a of the light guide plate 110a, and the light adjusting element 130a is located on the front surface 114a of the light guide plate 110a and covers the microstructure region 111 a. With such a design, the light guide assembly 100f can still have the same functions as the light guide assembly 100e of fig. 8.

Fig. 10 is a top view of a light guide assembly 100g according to an embodiment of the invention. The light guide assembly 100g includes a light guide plate 110b and

light sources

120a and 120 b. The difference from the embodiment of fig. 5 is that: the profile of the microstructures in the microstructure region 111b of the light guide plate 110b is circular. Referring to fig. 11 to 13, top views of light guide assemblies according to different embodiments of the present invention are respectively shown. The difference from the embodiment of fig. 10 is that: the outlines formed by the microstructures in the microstructure area of the light guide plate can be respectively in an oval shape, a triangular shape and a trapezoidal shape.

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.

Claims

1. A light guide assembly, comprising:

a plurality of light sources; and

the light guide plate is provided with a shielding area, a visible area, a plurality of microstructure areas, a light incident surface, a front surface and a back surface which are opposite, wherein the shielding area surrounds the visible area, the light incident surface is positioned between the front surface and the back surface and is adjacent to the front surface and the back surface, the microstructure areas are positioned on the front surface or the back surface and are close to the light incident surface, the microstructure areas are respectively aligned with the light sources, the microstructure areas in the shielding area are only positioned at positions corresponding to the light sources, the microstructure areas and the visible area are not overlapped with each other, a plurality of microstructures are arranged in any one of the microstructure areas, and the light sources are positioned outside the light guide plate and face the light incident surface of the light guide plate.

2. The light guide assembly of claim 1, wherein a distance between the plurality of microstructure regions and the light incident surface of the light guide plate is in a range from 1mm to 5 mm.

3. The light guide assembly of claim 1, wherein the microstructures in the microstructure regions have a rectangular, circular, elliptical, triangular, or trapezoidal profile.

4. The light guide assembly of claim 1, wherein the plurality of microstructures in the plurality of microstructure regions are either bumps or pits.

5. The light guide assembly of claim 1, further comprising:

when the plurality of microstructure areas are positioned on the front surface of the light guide plate, the light adjusting element is positioned on the front surface and covers the plurality of microstructure areas; when the plurality of microstructure areas are positioned on the back surface of the light guide plate, the light adjusting element is positioned on the back surface and covers the plurality of microstructure areas.

6. The light guide assembly of claim 5, wherein the light modifying element has first and second opposing edges, the first and second edges being spaced apart by a distance that is no less than a width of the plurality of microstructure regions.

7. The light guide assembly of claim 5, wherein the light conditioning element has an adhesive layer and a light absorbing layer, the adhesive layer being positioned between the light absorbing layer and the light guide plate.

8. The light guide assembly of claim 7, wherein the difference between the refractive index of the adhesive layer and the refractive index of the light guide plate is in the range of 0.1 to 0.7.

9. The light guide assembly of claim 5, wherein the light adjusting element has an adhesive layer and a light diffusing layer, the adhesive layer being positioned between the light diffusing layer and the light guide plate.

10. The light guide assembly of claim 9, wherein the difference between the refractive index of the adhesive layer and the refractive index of the light guide plate is in the range of 0.1 to 0.7.

11. The light guide assembly of claim 1, further comprising:

the cover body covers the plurality of microstructure areas, the plurality of light sources and the shielding area of the light guide plate.

12. The light guide assembly of claim 11, wherein the plurality of microstructure regions are located in the shaded region of the light guide plate.

13. The light guide assembly of claim 1, wherein the plurality of light sources are electrically connected to at least two driving elements.

14. The light guide assembly of claim 13, wherein a first portion of the plurality of light sources has a first color temperature, a second portion of the plurality of light sources has a second color temperature, and the first portion and the second portion of the plurality of light sources are electrically connected to the two driving elements, respectively.

15. The light guide assembly according to claim 13, wherein a first portion of the light sources has a first color, a second portion of the light sources has a second color, and the first portion and the second portion of the light sources are electrically connected to the two driving elements, respectively.