TWI382242B - Light-guiding structrure, light guide plate and backlight module having the same - Google Patents

Description

Light guiding structure, light guide plate and backlight module

The invention relates to a light guiding structure and a light guiding plate, in particular to a light guiding structure and a light guiding plate which simultaneously have the effects of light expansion and light collecting.

Flat panel displays enable many electronic devices to be thinned. Liquid crystal displays, which are currently commonly used in various electronic devices, use passive illumination to display images, and backlight modules are one of the important components of such flat displays. In order to make the light output more uniform and increase the brightness, a backlight module usually includes a diffuser having a light-expanding function and a brightness enhancement film (BEF) having a light collecting function. For example, the optical film of the conventional side-lit backlight module mostly includes two brightness enhancing films and one piece of light diffusing film. The optical film of the direct type backlight module mostly includes a light-diffusing plate and three light-expanding sheets, or a brightness enhancement film and two light-emitting sheets. Although the optical film combination of the backlight module has better optical characteristics, the cost of the backlight module cannot be effectively reduced. In addition, since the surface structure of the brightness enhancing film is highly regular, the primary refracted light and the secondary refracted light interfere to cause a moire phenomenon.

Therefore, if a light guiding structure design is provided to have both light expansion and light collecting effects, the effect of maintaining good optical characteristics while reducing the manufacturing cost of the backlight module can be obtained.

The present invention provides a light guiding structure having both a light-expanding and collecting effect and a light guiding plate and a backlight module including the light guiding structure.

According to an embodiment of the invention, a light guiding structure includes a light incident surface, a light exit surface, and at least one elongated trench. The light-emitting surface has a curved surface and protrudes from the light-incident surface, and the opening of the elongated groove is formed on the light-emitting surface, and the long-axis direction of the elongated groove is perpendicular to the normal direction of the light-incident surface and the light-guiding structure is divided Big A complex block that is symmetrically distributed.

According to another embodiment of the present invention, a light guide plate includes a light transmissive substrate and a plurality of first light guiding structures. The transparent substrate has a first light incident surface and a first light exit surface. The first light guiding structure is disposed on the transparent substrate, and each of the first light guiding structures includes a second light incident surface, a second light emitting surface, and at least one elongated groove. The second light-incident surface is attached to the first light-emitting surface of the transparent substrate, and the second light-emitting surface has a curved surface and protrudes from the second light-incident surface. The opening of the elongated groove is formed on the second light-emitting surface, and the long-axis direction of the elongated groove is perpendicular to the normal direction of the second light-incident surface and the light-conducting structure is divided into a plurality of substantially symmetrically distributed blocks.

According to another embodiment of the present invention, a backlight module includes a light transmissive substrate, a plurality of first light guiding structures disposed on the light transmissive substrate, and at least one light emitting element. The light transmissive substrate has a first light incident surface and a first light emitting surface, and each of the first light guiding structures includes a second light incident surface, a second light emitting surface, and at least one elongated trench. The second light-incident surface is attached to the first light-emitting surface of the transparent substrate, and the second light-emitting surface has a curved surface and protrudes from the second light-incident surface. The opening of the elongated groove is formed on the second light-emitting surface, and the long-axis direction of the elongated groove is perpendicular to the normal direction of the second light-incident surface and the light-conducting structure is divided into a plurality of substantially symmetrically distributed blocks. The light emitting element is disposed on one side of the first light incident surface of the light transmissive substrate.

With the design of the foregoing various embodiments, the curved light-emitting surface of the light guiding structure can provide a light-expanding effect and avoid the occurrence of moiré, and the elongated groove provided on the curved light-emitting surface can make the light be grooved. The inner wall reflects or refracts while obtaining the effect of collecting light.

Referring to FIG. 1a and FIG. 1b, a light guiding structure 1 according to an embodiment of the invention includes a light incident surface 11 and a light exit surface 12. The light incident surface 11 is a flat surface and the light exit surface 12 protrudes from the light incident surface 11 and In a curved surface, for example, the light-emitting surface 12 can be an arc surface, an elliptical arc surface, a paraboloid or a hyperboloid, and the like. Furthermore, the light guiding structure 1 has an opening formed on the light-emitting surface 12 and opened toward the light-incident surface 11 The elongated groove 13 has a long axis direction (illustrated as a Y direction) perpendicular to a normal direction (illustrated as a Z direction) of the light incident surface 11 to divide the light guiding structure 1 into two shapes. An approximately identical and symmetrically distributed arcuate body. Further, since the tolerance is generated in the actual process, the light guiding structure 1 does not necessarily need to form two arc bodies having a completely symmetrical shape, but an arc shape having a substantially symmetrical shape can obtain the same effect. In the embodiment shown in Fig. 1b, the section formed by cutting the groove 13 in the direction of the vertical long axis (i.e., in the X direction) has a V-shaped profile. For example, the angle of the V-shaped profile apex angle θ may range from 30 to 140 degrees, preferably 50 to 100 degrees. It should be noted that the inner wall of the groove 13 is not limited to a plane but also a curved surface, so the cross section of the groove 13 may also have a U shape, a circular arc shape, an elliptical arc shape, a parabolic shape or a hyperbolic shape. profile.

Referring to FIG. 1b, by the arrangement of the grooves 13, the light beam L1 having a larger incident angle can be reflected by the inner wall of the groove 13 to a set direction, and the light beam L2 having another incident angle is covered by the inner wall of the groove 13. The light is refracted to the set direction, so the light guiding structure 1 having the V-shaped groove of the present embodiment can provide the effect of collecting light. In addition, please refer to the traveling path of the light beam L3, which is reflected by the inner wall of the groove 13 to the curved light-emitting surface 12, and is refracted to form a large light-emitting angle, so that the guide of the curved light-emitting surface 12 of this embodiment The light structure 1 also has the effect of light expansion. Furthermore, the effect of collecting light can be controlled by adjusting the angle of the inner wall of the groove 13 with respect to the light incident surface 11, and the effect of light amplification can be controlled by adjusting the curvature of the light surface 12.

It should be noted that the number of grooves of the light guiding structure of the present invention is not limited to one, and may also include a plurality of grooves. Referring to FIG. 2, a light guiding structure 2 according to another embodiment of the present invention is similar to the light guiding structure 1. The difference is that the light guiding structure 2 has two V-shaped grooves 13, 13' intersecting each other, that is, two V-shaped shapes. The long axis directions of the grooves 13, 13' are vertically staggered with each other, so that the light guiding structure 2 is divided into four substantially symmetrically distributed arc bodies. Similarly, since the tolerance is generated in the actual process, the light guiding structure 2 does not necessarily need to form four arc-shaped bodies with completely symmetrical shapes, but an arc-shaped body having a substantially symmetrical shape can obtain the same effect. Referring to FIG. 3, the light guiding structure 3 of another embodiment of the present invention is similar to the light guiding structure 2, and is poor. The other reason is that the light guiding structure 3 does not form the groove 13 extending across the entire light incident surface as shown in FIG. 1 or FIG. 2, but retains the side wall 14 at both ends of the groove 13, and The outer surface of the side wall 14 is a curved surface extending from the light-emitting surface 12, and the curved outer surface of the side wall 14 can further enhance the light-expanding effect.

The size of the light guiding structure of the present invention can be arbitrarily enlarged and reduced to be applied to various optical elements. The following describes the application of the light guiding structure of the present invention, but is not limited to the embodiments set forth below. Referring to FIG. 4 , a light guide plate 4 according to an embodiment of the invention includes a transparent substrate 41 and a plurality of first light guiding structures 42 . The transparent substrate 41 has a first light incident surface 411 and a first light exit surface 412. The first light guiding structure 42 has a second light incident surface 421 , a second light emitting surface 422 , and an elongated trench 423 . The second light-incident surface 421 is attached to the first light-emitting surface 412 of the transparent substrate. The second light-emitting surface 422 has a curved surface and protrudes from the second light-incident surface 421, and the opening of the elongated trench 423 is formed in the second light-emitting surface. On face 422. The long axis direction of the elongated groove 423 is perpendicular to the normal direction of the second light incident surface 421 and divides the light guiding structure 42 into a plurality of substantially curved symmetrical blocks. It should be noted that the light incident surface of the light guide plate applied to the direct type backlight module is a light incident surface 411 parallel to the first light exit surface 412, and the light incident surface of the light guide plate applied to the side light type backlight module is a vertical first light output. The light incident surface 411' of the surface 412.

Referring to FIG. 5a to FIG. 5d, the plurality of first light guiding structures 42 may be arranged on the surface of a transparent substrate 5 in different manners, for example, they may be arranged in a matrix (shown in FIG. 5a) and concentric circles (shown in FIG. 5b). ), a polygon (shown in Figure 5c), a wave (shown in Figure 5d), or even an irregular arrangement. In addition, the density of the light guiding structure 42 arranged on the surface of the transparent substrate 5 can be arbitrarily designed according to requirements, and the transparent substrate 5 can be a transparent film, a diffusion sheet, a brightness enhancement film, a polarizing film, or A backlight board or the like can be used.

Referring to FIG. 6 a , the light guide plate according to an embodiment of the invention may further include second light guiding structures 43 , 44 , 45 disposed on the light incident surface 411 and opposite to the first light guiding structure 42 . For example, the plurality of second light guiding structures may be arc-shaped structures (as indicated by reference numeral 43), elliptical curved structures, parabolic structures, hyperbolic structures, and V-shaped structures (such as reference numeral 44) in which the long axis directions are parallel to each other. Show), ladder structure (such as Reference numeral 45), a conical structure, a polygonal pyramid structure or a combination of the above. It should be noted that in the embodiment shown in FIG. 6a, the second light guiding structures 43, 44, 45 are elongated, but are not limited thereto, and the second light guiding structure may also be a discontinuous bump structure. In addition, as shown in FIG. 6 b , the first light guiding structure 42 disposed on the light emitting surface 412 can also be disposed on the light incident surface 411 as the second light guiding structure 46 .

Referring to FIG. 7 , the direct type backlight module 7 includes a light guide plate 4 and a light emitting element 71 , and the light guiding structure 42 is formed on the light emitting surface 412 . The light-emitting element 71 is disposed on one side of the light-incident surface 411 of the light guide plate 4. The embodiment shown in FIG. 7 is a direct-type backlight module, so that the light-incident surface 411 of the light guide plate 4 is parallel to the light-emitting surface 412. The backlight module 7 of the embodiment further includes an optical film 72 disposed between the light guide plate 4 and the light-emitting element 71. For example, the optical film 72 can be a light diffuser, a polarizer, or a combination of the above, and the like. In addition, although the optical substrate provided with the first light guiding structure 42 in the present example is exemplified as a light guide plate 4, it is not limited, and may be, for example, a haze having a haze or a haze having no haze. Film layer and so on.

Referring to FIG. 8 , an edge-light type backlight module 8 according to an embodiment of the present invention includes a light guide plate 4 and a light-emitting element 81 . The light-guiding structure 42 is formed on the light-emitting surface 412 , and the light-emitting element 81 is disposed on the light guide plate 4 . One side of the light incident surface 411'. The embodiment shown in FIG. 8 is a side light type backlight module. Therefore, the light incident surface 411 ′ of the light guide plate 4 is perpendicular to the light exit surface 412 , and a reflective layer 82 is disposed on the other side of the light guide plate 4 opposite to the light exit surface 412 . . For example, the light-emitting elements 71 and 81 of the backlight modules 7 and 8 may be a Light-Emitting Diode (LED) or a Cold Cathode Fluorescent Lamp (CCFL). Furthermore, although not depicted in FIG. 8 , those skilled in the art will be able to understand that an optical film structure such as a diffusion sheet or a enamel enhancement sheet can be further disposed above the light guide plate 4 to further improve light emission brightness and light uniformity. .

Please refer to Table 1 and Table 2 to illustrate the optical benefits of the light guide plate of the present invention applied to a backlight module.

Table 1 is a comparison table of optical characteristics of a light guide plate and a commercially available optical film applied to a direct type backlight module according to an embodiment of the present invention. As can be seen from Table 1, the light guide plate of the present invention is applied to a direct type backlight module, and the brightness enhancement benefit is 14% higher than that of the commercially available product 1 and 23% higher than the commercially available product 2; the light extraction efficiency is higher than that of the commercially available product 1 It is 59.1% higher, which is 8.3% higher than that of the commercially available product 2. In addition, when the light guide plate of the present invention is applied to a direct type backlight module, the change in viewing angle is relatively smooth, and a better visual effect can be provided.

Table 2 is a comparison table of optical characteristics of a light guide plate and a commercially available optical film used in an edge-light type backlight module according to an embodiment of the present invention. It can be seen from Table 2 that the light guide plate of the present invention is applied to the edge-light type backlight module, and the brightness enhancement effect is only 5.8% lower than that of the commercially available product 1, and the light extraction efficiency is 52.29% higher; compared with the commercially available product 2, The brightening benefit is 26.4% higher than that of the commercially available product 2, and the light extraction efficiency is 4.49% higher. In addition, when the light guide plate of the present invention is applied to the edge-light type backlight module, the change of the viewing angle is relatively smooth, and the comparison can be provided. Good visual effects.

With the design of the foregoing various embodiments, the curved light-emitting surface of the light guiding structure can provide a light-expanding effect and avoid the occurrence of moiré, and the elongated groove provided on the curved light-emitting surface can make the light be grooved. The inner wall reflects or refracts while obtaining the effect of collecting light. In addition, the design according to the embodiment of the present invention can obtain a smoother change in viewing angle, and thus the visual effect is better.

The above is intended to be illustrative only and not limiting. Equivalent modifications may be made to the embodiments of the invention described above without departing from the spirit and scope of the invention. Therefore, any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

1, 2, 3‧ ‧ light guiding structure

11‧‧‧Into the glossy surface

12‧‧‧Glossy

13, 13’‧‧‧ trench

14‧‧‧ side wall

4‧‧‧Light guide plate

41‧‧‧Transparent substrate

411, 411'‧‧‧ into the glossy surface

412‧‧‧The first glazing

42‧‧‧First light guiding structure

421‧‧‧Second entrance

422‧‧‧second glazing

423‧‧‧ trench

43, 44, 45, 46‧‧‧ second light guiding structure

5‧‧‧Optical substrate

7, 8‧‧‧ backlight module

71, 81‧‧‧Lighting elements

72‧‧‧Optical diaphragm

82‧‧‧reflective layer

L1, L2, L3‧‧‧ ray path

Θ‧‧‧ top angle

Fig. 1a is a perspective view showing a light guiding structure according to an embodiment of the present invention.

Figure 1b is a side elevational view of a light directing structure in accordance with one embodiment of the present invention.

2 is a perspective view showing a light guiding structure according to another embodiment of the present invention.

Fig. 3 is a perspective view showing a light guiding structure according to another embodiment of the present invention.

Fig. 4 is a side elevational view showing a light guide plate according to an embodiment of the present invention.

5a to 5d are schematic views showing an arrangement of light guiding structures on a light guiding plate.

Figure 6a is a perspective view showing a light guide plate according to another embodiment of the present invention.

Figure 6b is a side elevational view of a light guide plate in accordance with another embodiment of the present invention.

FIG. 7 is a side view showing a backlight module according to an embodiment of the present invention.

FIG. 8 is a side view showing a backlight module according to another embodiment of the present invention.

1‧‧‧Light guiding structure

11‧‧‧Into the glossy surface

12‧‧‧Glossy

13‧‧‧ trench

L1, L2, L3‧‧‧ ray path

Θ‧‧‧ top angle

Claims (42)

A light guiding structure comprising: a light incident surface, which is a plane; a light exiting surface, which has a curved surface and protrudes from the light incident surface; and at least one elongated groove, the opening of the elongated groove Formed on the light-emitting surface, and the long-axis direction of the elongated groove is perpendicular to the normal direction of the light-incident surface, and the light-conducting structure is divided into a plurality of substantially symmetrically distributed blocks, and partially passes through the light-incident surface Light is reflected by the inner wall of the elongated groove. The light guiding structure of claim 1, wherein the blocks are arcs having substantially the same shape. The light guiding structure according to claim 1, wherein the portion of the light exiting surface excluding the elongated groove is a circular arc surface, an elliptical arc surface, a paraboloid or a hyperboloid. The light guiding structure of claim 1, wherein the inner wall of the groove is a plane or a curved surface. The light guiding structure according to claim 1, wherein the cross section of the groove cut along a direction perpendicular to the long axis thereof has a U-shaped, circular arc-shaped, elliptical curved, parabolic or hyperbolic contour. The light guiding structure according to claim 1, wherein the cross section of the groove cut along a direction perpendicular to its long axis has a V-shaped profile, and the V-shaped profile has an apex angle ranging from 30 to 140 degrees. The light guiding structure of claim 1, wherein the grooves are two lanes and are vertically staggered with each other. The light guiding structure of claim 1, wherein the groove extends in the long axis direction across the entire light incident surface. The light guiding structure according to claim 1 of the patent application, further comprising two grooves respectively formed in the groove a side wall of the end, and an outer surface of the side wall extends from the light exiting surface. A light guide plate comprising: a light transmissive substrate having a first light incident surface and a first light emitting surface; and a plurality of first light guiding structures disposed on the light transmissive substrate and each of the first light guiding structures comprises a second light incident surface, the first light emitting surface of the transparent substrate is attached, and the second light incident surface is a plane; a second light emitting surface is curved and protrudes from the second light emitting surface a light-incident surface; and at least one elongated groove, the opening of the elongated groove is formed on the second light-emitting surface, and a long-axis direction of the elongated groove is perpendicular to a normal direction of the second light-incident surface The light guiding structure is divided into a plurality of substantially symmetrically distributed blocks, and light rays partially passing through the second light incident surface are reflected by the inner wall of the elongated groove. The light guide plate of claim 10, wherein the blocks are arcs having substantially the same shape. The light guide plate of claim 10, wherein the portion of the second light exiting surface excluding the elongated groove is a circular arc surface, an elliptical curved surface, a paraboloid or a hyperboloid. The light guide plate of claim 10, wherein the inner wall of the groove is a flat surface or a curved surface. The light guide plate of claim 10, wherein the cross section of the groove cut along a direction perpendicular to its long axis has a U-shaped, circular arc-shaped, elliptical curved, parabolic or hyperbolic profile. The light guide plate of claim 10, wherein the cross section of the groove cut along a direction perpendicular to the long axis thereof has a V-shaped profile, and the V-shaped profile has an apex angle ranging from 30 to 140 degrees. The light guide plate of claim 10, wherein the groove is two lanes and hangs each other Straight interlaced. The light guide plate of claim 10, wherein the groove extends in a direction along a long axis direction across the second light incident surface. The light guide plate of claim 10, wherein each of the first light guiding structures further comprises a side wall respectively formed at two ends of the groove, and an outer surface of the side wall extends from the second light emitting surface. The light guide plate of claim 10, wherein the first light guiding structures are arranged in a matrix, a concentric circle, a polygonal shape, a wave shape or an irregular shape on the first light emitting surface. The light guide plate of claim 10, further comprising a plurality of second light guiding structures formed on the first light incident surface of the light transmissive substrate. The light guide plate of claim 20, wherein the second light guiding structures are circular arc structures parallel to each other in a long axis direction, an elliptical arc structure, a parabolic structure, a hyperboloid structure, a V-shaped structure, and a trapezoidal shape. Structure, conical structure, polygonal pyramid structure or a combination of the above. The light guide plate of claim 20, wherein the second light guide structure has the same outer shape as the first light guide structure. The light guide plate of claim 10, wherein the first light incident surface and the first light exit surface of the light transmissive substrate are perpendicular to each other. The light guide plate of claim 10, wherein the first light incident surface and the first light exit surface of the light transmissive substrate are parallel to each other. A backlight module includes: a light-transmitting substrate having a first light-incident surface and a first light-emitting surface; and a plurality of first light-guiding structures disposed on the light-transmitting substrate and each of the first light guides The structure comprises: a second light-incident surface, the first light-emitting surface of the light-transmitting substrate is attached, and the second light-incident surface is a plane; and a second light-emitting surface is curved and protrudes from The second light incident surface; and At least one elongated groove, the opening of the elongated groove is formed on the second light emitting surface, and a long axis direction of the elongated groove is perpendicular to a normal direction of the second light incident surface and the light guiding structure is Dividing into a substantially symmetrically distributed plurality of blocks, and a portion of the light passing through the second light incident surface is reflected by the inner wall of the elongated groove; and at least one light emitting element disposed on the first input of the light transmissive substrate One side of the glossy side. The backlight module of claim 25, wherein the first light incident surface and the first light emitting surface of the light transmissive substrate are perpendicular to each other. The backlight module of claim 25, wherein the first light incident surface and the first light exiting surface of the light transmissive substrate are parallel to each other. The backlight module of claim 25, wherein the transparent substrate is a light transmissive film, a diffusion sheet, a brightness enhancement film, a polarizing film or a backlight. The backlight module of claim 25, wherein the blocks are arcs having substantially the same shape. The backlight module of claim 25, wherein the portion of the second light exiting surface excluding the elongated groove is a circular arc surface, an elliptical curved surface, a paraboloid or a hyperboloid. The backlight module of claim 25, wherein the inner wall of the groove is a flat surface or a curved surface. The backlight module of claim 25, wherein the cross section of the groove cut along a direction perpendicular to its long axis has a U-shaped, circular arc-shaped, elliptical curved, parabolic or hyperbolic profile. The backlight module of claim 25, wherein the cross section of the groove cut along a direction perpendicular to its long axis has a V-shaped profile, and the V-shaped profile has an apex angle ranging from 30 to 140 degrees. The backlight module of claim 25, wherein the groove is two and mutually Vertically staggered. The backlight module of claim 25, wherein the groove extends in the long axis direction across the entire second light incident surface. The backlight module of claim 25, wherein each of the first light guiding structures further comprises a sidewall formed at each end of the trench, and an outer surface of the sidewall extends from the second light emitting surface. The backlight module of claim 25, wherein the first light guiding structures are arranged in a matrix, a concentric circle, a polygonal shape, a wave shape or an irregular shape on the first light emitting surface. The backlight module of claim 25, further comprising a plurality of second light guiding structures formed on the first light incident surface of the light transmissive substrate. The backlight module of claim 38, wherein the second light guiding structures are circular arc structures, elliptical arc structures, parabolic structures, hyperboloid structures, V-shaped structures, which are parallel to each other in the long axis direction, A trapezoidal structure, a conical structure, a polygonal pyramid structure, or a combination thereof. The backlight module of claim 38, wherein the second light guiding structure has the same outer shape as the first light guiding structure. The backlight module of claim 25, further comprising a reflective layer disposed on the other side of the light-transmitting substrate opposite to the first light-emitting surface. The backlight module of claim 25, wherein the light emitting element is a light emitting diode or a cold cathode fluorescent lamp.