WO2011091674A1

WO2011091674A1 - Light guide plate, illumination device and backlight module both comprising the same

Info

Publication number: WO2011091674A1
Application number: PCT/CN2010/077645
Authority: WO
Inventors: 刘龙辉
Original assignee: 苏州奥浦迪克光电技术有限公司
Priority date: 2010-01-28
Filing date: 2010-10-11
Publication date: 2011-08-04
Also published as: CN101776246B; CN101776246A

Abstract

A light guide plate (100) comprises a light incidence surface (130), a light reflecting surface (120), and a light emitting surface (110). The light emitting surface (110) is located at an upper surface of the light guide plate (100). The light reflecting surface (120) is located at a lower surface of the light guide plate (100). The light incidence surface (130) is located at a lateral surface between the upper surface and the lower surface of the light guide plate (100). The light reflecting surface (120) is provided with a plurality of reflecting elements (121) parallel to the light incidence surface (130). The reflecting element (121) is protruded or concaved from the lower surface of the light guide plate (100) in a prismatic shape. The shape of the cross section of the reflecting element (121) is an obtuse triangle which consists of a first reflecting surface (121a), a second reflecting surface (121b), and the lower surface of the light guide plate (100). An illumination device (200) and a backlight module (300) both comprising the light guide plate (100) are provided. The light guide plate (100) enables light to be emitted from the light emitting surface (110) uniformly and vertically.

Description

Light guide plate and illumination device and backlight module including the same

Technical field

The present invention relates to a light guide plate in the field of optics, and in particular to a lighting device and a backlight module including such a light guide plate.

Background technique

The light guide plate is an optical element for converting a point light source or a line light source into a surface light source, and generally has a light incident surface, a light reflecting surface and a light exiting surface, wherein the light incident surface is for receiving the light beam emitted by the light source and introducing the light beam Inside the light guide plate, the light reflecting surface reflects and scatters the introduced light beam to form a scattered light beam uniformly dispersed in each direction, and the light emitting surface leads the uniformly dispersed light beam to the light guide plate, and the light reflection surface reflects the reflection and scattering of the light beam. Reflective elements on the light reflecting surface are realized. Reflective elements are generally classified into grooves or prisms, printing dots, laser scoring, etc., and depending on the reflective elements, the processing methods are also classified into mechanical processing, printing, laser processing, and chemistry. Etching and other methods.

The design focus and difficulty of the light guide plate is how to make the light uniform and as perpendicular as possible to exit from the light exit surface. In order to solve this problem, one solution in the prior art is that the light reflecting surface of the light guide plate has a plurality of printed dots arranged in a matrix. Or laser scoring, the diameter of the dot can vary from small to large in the direction away from the incident surface, but the uniformity of the light guide plate and the exit angle of the light guide plate using the dot can not meet the requirement of the uniformity of the light guide of the liquid crystal display panel. If the light distribution in a small area is slightly adjusted to achieve a more uniform light distribution, it is necessary to adjust the dot diameter or the spacing to have difficulty in the process. Another solution is to provide a plurality of U-shaped or V-shaped reflective elements on the light reflecting surface. Since each of the reflecting elements has the same outer dimension, it is easy to cause a portion of the light guide plate to be close to the light source to have a higher brightness, and to be far away. A technical problem in which the brightness of the light source is low. Because of the above problems in the prior art, in the backlight module, a plurality of diffusion plates and a prism plate must be disposed above the light guide plate to further deflect the light to the near normal direction, thereby causing the overall thickness of the backlight module. Larger and more expensive.

Summary of the invention

In order to overcome the deficiencies in the prior art, an object of the present invention is to provide a light guide plate capable of uniformly and vertically emitting light from a light exit surface, thereby providing a lighting device and a backlight module having a simple structure and a thinner thickness.

In order to achieve the above object, the present invention provides a light guide plate having a light incident surface, a light reflecting surface, and a light emitting surface. The light reflecting surface is located on a lower surface of the light guiding plate, and the light emitting surface is located at the light guiding plate. The upper surface, the light incident surface is located on a side surface between the upper surface and the lower surface of the light guide plate, and the light reflecting surface has a plurality of reflective elements protruding in a prism shape or recessed on the lower surface of the light guide plate, and the reflective element is parallel to the light. The incident surface, the cross section of the reflective element is an obtuse triangle, and the obtuse triangle is composed of the first reflective surface, the second reflective surface and the lower surface of the light guide plate; the first reflective surface and the lower surface of the light guide plate have an angle α, and the angle α is The direction away from the light incident surface varies in the range of α1 to α2 to α3, and α3>α1>α2, α1 is in the range of 3° to 7°, α2 is in the range of 2° to 6°, and α3 is in 4°. In the range of 8°; the second reflecting surface and the lower surface of the light guide plate have a β angle, and the β angle varies in a range away from the light incident surface in the range of β1 to β2 to β3, and β2>β1>β3, and β1 is at 41°. In the range of ~47°, β2 is in the range of 43° to 49°. Inner, β3 in the range of 40 ° ~ 46 °.

Preferably, in order to make the light more uniformly emitted, the height of the retroreflective element gradually increases in a direction away from the light incident surface, and the distance of the reflective element gradually decreases away from the light incident surface.

More preferably, the height of the retroreflective element varies from 2 μm to 15 μm, and the pitch of the retroreflective elements varies from 160 μm to 90 μm.

Preferably, the light incident surface has a one-dimensional or two-dimensional diffraction grating, and the diffraction grating is of a micron order or a submicron order.

Preferably, the light exit surface has a plurality of concentrating elements protruding or recessed on the surface of the light guide plate, and the concentrating elements are perpendicular to the light incident surface.

Preferably, the light guide plate has a wedge shape or a flat plate shape.

According to another aspect of the present invention, a lighting device includes an outer frame and a reflective plate, a light guide plate, and a diffusing plate disposed in the outer frame in order from the bottom to the top, and the light incident surface of the light guide plate is disposed near the light incident surface. LED light source.

Preferably, the light guide plate is formed by splicing a plurality of light guide plate units.

According to another aspect of the present invention, a backlight module includes an outer frame and a reflective plate, a light guide plate, and a diffusing plate disposed in the outer frame in sequence from bottom to top, and the light incident surface of the light guide plate is disposed near the light incident surface. There are LED light sources.

Due to the adoption of the above technical solutions, the present invention has the following advantages: since the retroreflective element of the present invention has an obtuse angle triangle whose gradual change gradually changes, the incident light at a small angle close to the incident surface and the farther away from the incident surface are The large-angle incident light can achieve a good reflection effect, and β is at a large angle, so that the reflected light is directly biased toward the near normal direction; in addition, the concentrating element of the present invention can be perpendicular to the LED light in the illuminating surface. The outgoing light is further concentrated in the axial direction, so that the outgoing light is more concentrated and emitted in the near normal direction. Therefore, after the light guide plate is used, the illumination device and the backlight module only need to have a diffusion plate disposed above the light guide plate to achieve the angle deflection requirement, which greatly simplifies the structure, reduces the thickness, and reduces the production cost.

DRAWINGS

Figure 1 is a perspective view of a light guide plate of the present invention;

Figure 2 is a schematic view of the light reflecting element of the lower surface of the light guide plate of Figure 1;

Figure 3 is a schematic view of a concentrating element on the surface of the light guide plate of Figure 1;

Figure 4 is a perspective view of an embodiment of a lighting device including a light guide plate of the present invention;

Figure 5 is a perspective view of the lighting device of Figure 4 after removing the diffuser plate and the light shielding sheet;

Figure 6 is a perspective exploded view of the lighting device of Figure 4;

Figure 7 is a perspective view of the lighting device of Figure 4 applied to a desk lamp;

Figure 8 is a perspective exploded view of another embodiment of a lighting device including a light guide plate of the present invention;

Figure 9 is a perspective view of the lighting device of Figure 8 applied to a taxi light;

Figure 10 is a perspective view of an embodiment of a backlight module including a light guide plate of the present invention;

Figure 11 is a perspective view of the light guide plate of Figure 10.

detailed description

The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings, in which the advantages and features of the invention can be more readily understood by those skilled in the art.

Referring to FIG. 1 to FIG. 3, the light guide plate 100 of the present embodiment has a light incident surface 130, a light reflecting surface 120, and a light emitting surface 110. The light reflecting surface 120 is located on the lower surface of the light guiding plate 100. The exit surface 110 is located on the upper surface of the light guide plate 100, and the light incident surface 130 is located on one side surface between the upper surface and the lower surface of the light guide plate 100.

As shown in FIG. 2, the light reflecting surface 120 has a plurality of light reflecting elements 121. The light reflecting elements 121 are parallel to the light incident surface 130. Each of the light reflecting elements 121 is prismaticly protruded from the lower surface of the light guiding plate 100. The cross section of the 121 is an obtuse triangle, and the obtuse triangle is composed of a first reflective surface 121a, a second reflective surface 121b, and a lower surface of the light guide plate 100. The first reflective surface 121a and the lower surface of the light guide plate 100 have an angle α, and the light is incident. The surface 121b and the lower surface of the light guide plate 100 have a β angle, and the α angle changes in a range from α1 to α2 to α3 in a direction away from the light incident surface, and α3>α1>α2, and α1 is in a range of 3° to 7°. Α2 is in the range of 2° to 6°, α3 is in the range of 4° to 8°; the β angle varies in the range of β1 to β2 to β3 along the direction away from the light incident surface, and β2>β1>β3, β1 is In the range of 41° to 47°, β2 is in the range of 43° to 49°, and β3 is in the range of 40° to 46°.

In order to make the light out more uniformly, the height of the retroreflective element gradually increases in a direction away from the light incident surface, the distance of the reflective element gradually decreases away from the light incident surface, and the height of the reflective element varies in the range of 2 μm to 15 μm, and the light is reflected. The pitch of the elements varies from 160 μm to 90 μm. It can be seen from the reflection paths of the two light rays having different exit angles in the figure that since the cross section of the light reflecting element 121 is an obtuse angle triangle whose gradual change gradually changes from the incident surface, the incident light at a small angle close to the incident surface and the pair The large-angle incident light far from the incident surface can have the same reflection effect, and β is at a large angle, so that the reflected light is directly biased toward the near normal direction.

As shown in FIG. 3, a plurality of concentrating elements 111 are disposed in parallel on the light exit surface 110. The concentrating elements 111 are prismaticly protruded from the upper surface of the light guide plate 100, and the plurality of concentrating elements 111 are perpendicular to the light incident surface. 130, each concentrating element 111 is composed of two opposite

inclined faces

111a, 111b and a circular arc surface 111c respectively tangential to the two

inclined faces

111a, 111b, and the

inclined faces

111a, 111b basically constitute an isosceles triangle, such as a bottom The angle may be about 45°, and the

inclined surfaces

111a and 111b and the circular arc surface 111c are combined to illuminate the light in the direction perpendicular to the optical axis of the LED in the light-emitting surface.

The light incident surface 130 can take various measures to increase the uniformity of the incident light. For example, the light incident surface 130 can be a polished surface or a diffuse reflective surface. Alternatively, the light incident surface 130 can be disposed. Similar to the lateral or longitudinal prism-like fine structure of the light exit surface 110 or the light reflecting surface 120, thereby changing the bright spot phenomenon at the entrance light; in addition, one-dimensional or two-dimensional diffraction of submicron order may be set on the light incident surface 130. The grating increases the coupling efficiency between the light source and the light guide.

It should be noted that the light guide plate 100 may be in the shape of a wedge or a flat plate. In addition, the light exit surface 110 and the light reflecting surface 120 may be processed by laser engraving or chemical etching to improve the brightness and uniformity. It is known to those skilled in the art and will not be described here.

4 is a perspective view of the illumination device 200 including the light guide plate, FIG. 5 is a perspective view of the illumination device 200 after the diffusion plate 240 and the light shielding plate 250 are removed, and FIG. 6 is a perspective view of the illumination device 200. The illuminating device 200 includes an outer frame 210 and a reflecting plate 220, a light guide plate 230, and a diffusing plate 240 which are disposed in the outer frame from the bottom to the top, and a light source 260 is disposed in the vicinity of the light incident surface of the light guide plate 230. 250 covers the gap between the diffusion plate 240 and the outer frame 210 from above. The light emitted from the light guide plate 230 is further collimated by the diffusion plate 240 and then emitted from the upper surface of the illumination device 200, and the light that is partially transmitted downward from the lower surface of the light guide plate 230 is again reflected by the reflection of the reflection plate 220. The upward emission is beneficial to improve the utilization efficiency of the light source and reduce the loss of light energy. The reflector 220, the light guide plate 230, and the diffusion plate 240 may be fixed on the inner side wall of the outer frame 210 by means of glue or screws. The distance between the diffusion plate 240 and the light guide plate 230 may be adjusted as needed, and the most Fortunately, it is more than 1cm. This type of lighting device is suitable for indoor, outdoor lighting, ultra-thin light boxes and backlight modules. It has the characteristics of energy saving and high efficiency, and the light emitted is very uniform, which is not easy to cause eye fatigue.

The light source in this embodiment uses an LED, and the LED light source 260 can be a side view type (Side View) LED), can also be top view type (Top View LED), if the top view type is adopted, the production cost of the lighting device can be further reduced; the LED here can be an RGB three-primary LED, or a pseudo white LED based on the principle of short-wavelength excitation phosphor emitting white light, if RGB three primary colors are used LEDs can be adjusted for color temperature depending on the environment. The LED can be fixed to the FPC (flexible circuit board) by a bonding process, and then the FPC is fixed on the outer frame 210 near the light incident surface 130 of the light guide plate. Since the LED is used as the light source, special attention should be paid to the heat dissipation problem of the LED to prevent the LED from shortening due to poor heat dissipation. Therefore, the outer frame 210 in this embodiment is made of an aluminum alloy material having good thermal conductivity.

Figure 7 illustrates a table lamp constructed by using the above illumination device. The table lamp is composed of a lighting device 200 and a bracket base 400. A light cover made of a transparent resin material may be disposed outside the light-emitting surface of the illumination device 200. To the protective effect; the base of the bracket 400 is provided with a power supply device such as an AC/DC conversion component, so that it can be directly connected to the daily household AC power supply to supply power to the LED. Of course, the power supply device such as the AC/DC conversion component can also be integrated into The power module is disposed outside the bracket base 400. According to the data measured by the test, when the power of the lamp is about 6W, the brightness is 16600cd/m2, the brightness uniformity is 83%, the emitted light is very uniform, and there is no glare, which is also the most significant with the existing LED table lamp. The difference is energy-efficient and the light emitted is very uniform, which is not easy to cause eye fatigue.

8 is a split view of another embodiment of the above lighting device. The difference between the present embodiment and the lighting device of FIG. 6 is that the light guide plate is long in the X direction due to the illumination device in the embodiment. 230 is a side-by-side arrangement of a plurality of smaller-sized light guide plate units in the X direction to form a light guide plate 230 having a larger size in the X direction. The light guide plate units can be fixed to each other by inserts, or can be fixed by various means such as glue or screws. This mutual splicing method is reduced compared with the direct production of large-sized light guide plates. Cost of production. This structure is also applicable to indoor lighting, outdoor lighting and backlight module devices such as flat lamps and ultra-thin light boxes.

Figure 9 depicts a taxi display card constructed using the above illumination device. The length direction dimension of the taxi display card in this embodiment is significantly larger than the other direction sizes, such as a length of 190 cm, a width of 80 cm, and a thickness. 2cm, therefore, a plurality of small-sized light guide plate units can be spliced to each other to form a large-sized light guide plate, which avoids the trouble of producing different sizes of light guide plates for products of different sizes, and reduces the production cost.

FIG. 10 illustrates a backlight module 300 including the above-mentioned light guide plate, which includes an outer frame 310 and a reflective plate 320, a light guide plate 330, a diffuser plate 340, and a light guide plate 330 which are sequentially stacked in the outer frame 310 from bottom to top. a plurality of LEDs are disposed near the light incident surface, The LED can be fixed on the FPC (flexible circuit board) by a bonding process, and then the FPC is fixed on the outer frame 210 near the light incident surface 130 of the light guide plate. The light emitted from the light guide plate 230 is further collimated by the diffusion plate 240 and then emitted from the upper surface of the backlight module 300, and the light transmitted from the lower surface of the light guide plate 230 is again emitted upward by the reflection of the reflection plate 220. It is beneficial to improve the utilization efficiency of the light source and reduce the loss of light energy.

As shown in FIG. 11, since the size of the backlight module 300 in the present embodiment is larger in the X direction and the Y direction, the light guide plate 330 is composed of a plurality of smaller light guide plate units 331 in the X direction. The Y direction is spliced together to form a light guide plate 330 having a larger size. As can be seen from the figure, the non-light incident surfaces of the adjacent light guide plate units 331 in the X direction and the Y direction are fixed to each other, and the light plate is fixed. The light incident surfaces of 330 are respectively located on both sides of the light plate 330, and the LED light source 361 and the LED light source 362 are respectively fixed in the vicinity of the light incident surface. The light guide plate units 331 can be fixed to each other by inserts, or can be fixed by various means such as glue or screws, which reduces the production cost of the product. It should be noted that in the manner of splicing each other, the shape and size of the light guide plate unit are not limited, and the splicing between the light guide plate units of various shapes and sizes may be performed, and details are not described herein. This structure is also applicable to indoor and outdoor lighting devices such as flat lamps and ultra-thin light boxes.

It is not difficult to see from the above embodiments that the present invention provides a light guide plate that allows light to be uniformly and vertically emitted from the light exit surface, thereby providing a lighting device and a backlight module having a simple structure and a thinner thickness.

The above embodiments are merely illustrative of the technical concept and the features of the present invention, and are intended to be understood by those skilled in the art and are not intended to limit the scope of the present invention. Equivalent variations or modifications made are intended to be within the scope of the invention.

Claims

A light guide plate having a light incident surface, a light reflecting surface and a light emitting surface, wherein the light reflecting surface is located on a lower surface of the light guiding plate, and the light emitting surface is located at the The upper surface of the light guide plate, wherein the light incident surface is located on a side surface between the upper surface and the lower surface of the light guide plate, wherein the light reflecting surface has a plurality of prismatic shapes a light reflecting element protruding or recessed on a lower surface of the light guide plate, wherein the light reflecting element is parallel to the light incident surface, the cross section of the light reflecting element is an obtuse triangle, and the obtuse triangle is a reflective surface, a second reflective surface, and a lower surface of the light guide plate;

The first reflecting surface and the lower surface of the light guide plate have an angle α, and the angle α is changed in a range away from the light incident surface in the range of α1 to α2 to α3, and α3>α1> Α2, the α1 is in the range of 3° to 7°, the α2 is in the range of 2° to 6°, and the α3 is in the range of 4° to 8°;

The second reflective surface has a β angle with the lower surface of the light guide plate, and the β angle varies in a range from β1 to β2 to β3 along a direction away from the light incident surface, and β2>β1> Β3, wherein β1 is in the range of 41° to 47°, β2 is in the range of 43° to 49°, and β3 is in the range of 40° to 46°.

2. The light guide plate according to claim 1, wherein a height of the light reflecting element gradually increases in a direction away from the light incident surface, and a distance of the light reflecting element is away from the light incident surface. The direction is gradually decreasing.

The light guide plate according to claim 2, wherein the height of the light reflecting element varies from 2 μm to 15 μm, and the pitch of the light reflecting element varies from 160 μm to 90 μm.

4. The light guide plate according to claim 1, wherein the light incident surface has a one-dimensional or two-dimensional diffraction grating, and the diffraction grating is of a micron order or a submicron order.

The light guide plate according to claim 1, wherein the light exit surface has a plurality of concentrating elements protruding or recessed on the surface of the light guide plate, and the gathering The light element is perpendicular to the light incident surface.

6. The light guide plate according to claim 1, wherein the light guide plate has a wedge shape or a flat plate shape.

A lighting device comprising the light guide plate according to any one of claims 1 to 6, characterized in that it comprises an outer frame and a reflecting plate and a guide arranged in the outer frame in this order from bottom to top. The light plate and the diffusion plate are provided with an LED light source in the vicinity of the light incident surface of the light guide plate.

The illuminating device according to claim 7, wherein the light guide plate is formed by splicing a plurality of light guide plate units.

A backlight module comprising the light guide plate according to any one of claims 1 to 6, characterized in that it comprises an outer frame and a reflective plate disposed in the outer frame in order from bottom to top, The light guide plate and the diffusion plate are provided with an LED light source in the vicinity of the light incident surface of the light guide plate.

The backlight module of claim 9, wherein the light guide plate is formed by splicing a plurality of light guide plate units.