TWI384291B - Optical plate with grooves in radiative alimentment for use in a backlight module - Google Patents

Description

Radial grooved optical substrate and backlight module using same

The present invention relates to an optical substrate used in a liquid crystal display device and a backlight module using the same, and more particularly to an optical substrate having a radially arranged light guiding groove and a backlight module using the same.

The backlight module is one of the key components of a liquid crystal display (LCD). Since the liquid crystal itself does not emit light, the function of the backlight module is to supply a sufficient light source with uniform brightness and distribution, and convert into a high-brightness and uniform brightness surface light source through a simple and effective optical mechanism to provide a backlight source of the liquid crystal display panel. LCD panels are now widely used in electronic products with potential for growth, such as monitors, notebook computers, digital cameras and projectors, especially for large-size panels such as notebook computers and LCD monitors. Group demand growth is also growing stronger.

The backlight module is mainly composed of a light source (for example, a cold cathode fluorescent tube, a hot cathode fluorescent tube, a light emitting diode), a reflector, a light guide plate, a diffusion sheet, and a cymbal sheet ( Brightness Enhancement Film, BEF) and other components assembled. After the light emitted by the light source enters the light guide plate, the light guide plate guides the incoming light to evenly distribute it into a light source. The reflector on the bottom side of the light guide plate reflects the light directed toward the reflector back into the light guide plate to prevent the light source. External leakage to increase the efficiency of light use. The light emitted by the light guide plate passes through the homogenizing action of the diffusing plate and the light collecting action of the breeze plate, thereby improving the brightness and uniformity of the light source, and then injecting the light into the liquid crystal panel. The cymbal is a regular arrangement of triangular ridges whose main function is by refraction and The internal total reflection refracts the light from the light guide plate to the scattered light in all directions and concentrates it in the direction of the on-axis angle of about ±35 degrees to improve the front brightness.

In recent years, with the maturity of Light Emitting Diode (LED) technology, backlight modules using LEDs as light sources have gradually been applied to small and medium-sized liquid crystal displays. Please refer to FIG. 1A, FIG. 1B, FIG. 2A and FIG. 2B. 1A is a relative positional view of the light guide plate 12 of the prior art and the LED light source 10. FIG. 1B is a light path diagram of the light emitted from the LED light source 10 of FIG. 1A passing through the light guide groove 14 of the light guide plate 12. 2A is a relative positional view of the light guide plate 22 of the prior art and the LED light source 20. FIG. 2B is a light path diagram of the light emitted from the LED light source 20 of FIG. 2A passing through the light guide groove 24 of the light guide plate 22. As shown in FIG. 1A, the LED light source 10 is generally designed on the long side or the short side of the light guide plate 12, and the light exit surface of the light guide plate 12 is generally designed to collect the V-shaped light guide groove 14 so that The light is deflected as far as possible in the direction of the forward light to increase the brightness. A V-shaped light guiding groove parallel to the direction of travel of light generally mate with more than two LED light sources 20. Alternatively, as shown in FIG. 2A, the arc-shaped V-shaped groove 24 is matched with a single LED light source 20.

Please refer to FIG. 3 and FIG. 4 . FIG. 3 is a schematic diagram showing a light collecting area of the light guide plate 12 when the LED light source 10 is disposed at a corner of the light guide plate 12 , and FIG. 4 illustrates the LED light source 20 when the LED light source 20 is disposed. A schematic view of a light collecting region of the light guide plate 22 at a corner of the light guide plate 22. With the increase of LED luminous intensity and cost reduction, the future trend is to use a single LED as the light source of the backlight module. In addition, in order to make the whole light-emitting picture uniform, the position of the LED light source is changed to the corner of the backlight module, but this will result in the conventional V-shaped groove 14 parallel to the light traveling direction and the arc-shaped V-shaped. The groove 24 can not only achieve the light collecting effect, but also has a light blocking effect. effect. As shown in FIG. 3 and FIG. 4, the light beams incident on the light guide plates 12 and 22 at the corners of the LED light sources 10 and 20 emit light at the front edges of the light guide plates 12 and 22, so that the light guide plates 12 and 22 are brought close to each other. Bright regions 16, 26 appear at one end of the light source 10, 20, and conversely there are dark regions 18, 28 at the end, which may cause uneven visual effects. In addition, when the alignment direction of the light guiding unit is too high in parallel with the liquid crystal array of the liquid crystal display panel to be used, the moiré caused by the light interference is easily generated. Furthermore, the conventional linear curved light guiding unit can only reflect the light in the vertical direction, so that the non-vertical light can not be effectively utilized due to the divergence.

In view of the above, the main object of the present invention is to develop an optical substrate on which radially arranged light guiding grooves are provided to solve the above problems of the prior art. The cross-sectional angle of the light guiding groove of the present invention is determined according to the light-emitting angle of the light source used, and the radial light guiding groove dot can be emitted from the center point of the light-emitting surface of the light source as a center position.

Another object of the present invention is to provide a backlight module including a light source and an optical substrate. The light source is disposed at a corner of the backlight module for generating a light, wherein the light source has a light emitting surface. The optical substrate includes a light emitting surface and a light incident surface. The light incident surface is disposed on a side of the optical substrate for receiving the light generated by the light source, and the light emitting surface is disposed on a liquid crystal display panel. The plane of the optical substrate is for emitting the light out of the optical substrate, and the light emitting surface has a plurality of first light guiding grooves for guiding the light received by the light incident surface. The plurality of first light guiding grooves are radially arranged in a center and distributed between a first side and a second side of the optical substrate, wherein a central axis of symmetry between the first side and the second side Is the normal to the center of the light-emitting surface of the light source, and the light intensity is 1 on the central axis of symmetry. The intensity of the light on the first side and the second side is 1/2.

According to an embodiment of the invention, the center of the light is the center point of the light emitting surface of the light source, or the center of the circle is the intersection of the light incident surface of the optical substrate and the central axis of symmetry. Or the center of the circle is free to move from the center point of the light emitting surface of the light source to the intersection of the light incident surface of the optical substrate and the central axis of symmetry on the central axis of symmetry.

The light-emitting surface of the optical substrate of the present invention has a first side and a second side, wherein the plurality of first light guiding grooves are arranged between the first side and the second side, and are radially arranged in a center. Starting from the second side to a side of the optical substrate, a plurality of second light guiding grooves are provided for guiding the light incident from the light incident surface, and the plurality of second light guiding grooves are parallel to the second side The first light guiding groove is not disposed between the first side and the second side. The groove depth and the groove pitch of the plurality of second light guiding grooves are adjustable. The optical substrate of the present invention comprises a light guide plate or a diffusion plate.

Another object of the present invention is to provide an optical substrate, comprising: a light emitting surface and a light incident surface, wherein the light incident surface is disposed on one side of the optical substrate, and the light emitting surface is disposed on a top side of the optical substrate, and a light source is generated. The light is incident on the light incident surface, and the optical substrate is emitted from the light exit surface. The optical substrate includes a plurality of first light guiding grooves disposed on the light emitting surface for guiding light rays incident from the light incident surface, wherein the plurality of first light guiding grooves are centered on the light source Radially arranged, and the angle and width of the cross section of each of the first light guiding grooves are adjusted according to the light emitting angle of the light source.

The light-emitting surface of the optical substrate of the present invention has a first side and a second side, wherein the plurality of first light guiding grooves are arranged between the first side and the second side, and are radially arranged in a center. Starting from the second side to one edge of the optical substrate and from the first side to the other edge of the optical substrate A plurality of second light guiding grooves are used for guiding light rays incident from the light incident surface, and the plurality of second light guiding grooves are parallel to the first light guiding grooves of the second side and the first side. The groove depth and the groove pitch of the plurality of second light guiding grooves are adjustable.

The optical substrate of the present invention comprises a light guide plate or a diffusion plate.

Please refer to FIG. 5, which is a schematic structural view of the display device 100 of the present invention. The display device 100 can be a liquid crystal display device including a backlight module 102 and a liquid crystal display panel 104. The backlight module 102 includes a light source 52, a reflective plate 54, and a light guide plate 56. The backlight module 102 is mainly assembled by components such as a light source (for example, a light-emitting diode) 52, a reflector 54, an optical substrate (in the present embodiment, the light guide plate 56), a diffusion plate 58, and cymbals 60 and 62. After the light emitted by the light source 52 enters the light guide plate 56, the light guide plate 56 guides the incoming light to evenly distribute it into a light source, and the reflector 54 reflects the light directed toward the reflector 54 back into the light guide plate 56 to prevent the light source. External leakage to increase the efficiency of light use. The light emitted from the light guide plate 56 passes through the uniform light action of the diffuser plate 58 and the light collecting action of the cymbals 60 and 62 to increase the brightness and uniformity of the light source, and then the light is incident on the liquid crystal display panel 104. In the preferred embodiment, the cymbals 60 and 62 are regular strip-shaped triangular ridges whose primary function is to refract light from the light guide 56 to the scattered light in all directions by refraction and internal total reflection. And focus on the angle of about ±35 degrees of the On-axis direction to improve the front brightness. The liquid crystal display panel 104 includes a liquid crystal molecular layer (not shown), and generates an image according to the light emitted from the light guide plate 56 and the direction of rotation of the liquid crystal molecules in the liquid crystal molecular layer. The light guide plate 56 includes a light incident surface 562 and a light exit surface 564. The light exit surface 564 is disposed on a plane of the light guide plate 56 corresponding to the liquid crystal display panel 104, and has a light exit surface 564. A plurality of light guiding grooves 566. The light incident surface 562 is located on the side of the light guide plate 56 adjacent to the light source for receiving the light generated by the light source 52. The light emitted from the light source 52 enters the light guide plate 56 from the light incident surface 562, and then the light is emitted from the light guide plate 56 via the light exit surface 564.

Referring to FIG. 6A and FIG. 6B, FIG. 6A is a relative positional view of the light guide plate and the light source according to the first embodiment of the present invention, and FIG. 6B is a relative positional view of the light guide plate and the light source according to the second embodiment of the present invention. The plurality of light guiding grooves 566 on the light emitting surface include at least a plurality of first light guiding grooves 82 and a plurality of second light guiding grooves 84 for guiding the light incident on the light guiding plate 56 to make the brightness of the light. It is evenly distributed on the light guide plate 56. The plurality of first light guiding grooves 82 are radially arranged at a center of a circle 524, wherein the dot 524 is a center point of the light emitting surface of the light source, and the light emitting surface of the light guiding plate is distributed from the first side 563. To the second side 561, and the axis 522 is the central axis of symmetry of the first side 563 and the second side 561, wherein the axis 522 is the normal to the center of the light emitting surface of the light source 52, and the light intensity is 1 on the axis 522. The intensity of the light on the first side 563 and the second side 561 is 1/2, and the angle and width of the cross section of each of the first light guiding grooves 82 are adjusted according to the light emitting angle α of the light source 52. The plurality of second light guiding grooves 84 are parallel to the first light guiding grooves 82b on the second side 561, and the spacing between the plurality of second light guiding grooves 84 is equidistant. It should be noted that in the first embodiment, the first side 563 of the first light guiding groove 82 overlaps with one edge of the light guide plate 56, and the second side 561 of the first light guiding groove 82 is also possible. The other edge of the light guide plate 56 is overlapped, so that there is no distribution of the second light guiding groove 84 (not shown) on the light guiding plate 56. However, the first side 563 of the first light guiding groove 82 may not be Referring to one of the edges of the light guide plate 56 and falling within the light guide plate 56, refer to FIG. 6B. The actual condition depends on the light intensity of the light source 52, and is not covered by the first light guide groove 82. respectively The plurality of second light guiding grooves 84b are covered by the first light guiding grooves 82c which are parallel to the first side 563.

Please refer to FIG. 7 and FIG. 8 , FIG. 7 is a relationship diagram between the luminous intensity of the light source of the present invention and the illuminating angle, and FIG. 8 is a relationship diagram of the distance between the first light guiding groove and the illuminating angle of the present invention. In Fig. 7, it can be found that the range of the light-emitting angle of the light source is preferably 0 to 60 degrees, preferably 0 to 20 degrees, and the range of the first light guiding groove is preferably 0.01 to 0.1 mm, and the best is 0.05~0.04 mm. As described above, each of the first light guiding grooves 82 has a V-shaped cross section, and the light-emitting angle α of the light source 52 has different luminous intensity to design a change in the pitch of the first light guiding grooves 82. Finally, as shown in FIG. 6 , where the first light guiding groove 82 is not covered, the second light guiding groove 82 b parallel to the second side 561 is used to fill the second guiding portion. The light trenches 84 are required to achieve the brightness and uniformity required for the development of the backlight module 102. The plurality of second light guiding grooves 84 are arranged at variable intervals and variable groove depths.

Please refer to FIG. 6A and FIG. 9 simultaneously. FIG. 9 is a relative position diagram of the light guide plate and the light source according to the third embodiment of the present invention. Referring to FIG. 9, the position of the dot 524' is located at the intersection of the light incident surface 562 of the light guide plate and the axis 522, and the center of the first light guiding groove 82 is radially arranged, that is, the dot 524 or 524'. The first light guiding groove is freely moved from the center point of the light emitting surface of the light source to the intersection point between the light guiding surface 562 and the axis 522 on the axis 522 thereof, compared to the dot 524 of FIG. 6A. The closer the dot 524' of the 84' is to the light guide plate 56, the larger the angle and the area occupied by the entire first light guiding groove 82 in the light guide plate 56, and the area occupied by the second light guiding groove 84 is The smaller. Therefore, there will be different effects on the overall optical performance. Whereas not covered by the first light guiding groove 82, the first light guiding groove 82b parallel to the second side 561 is respectively used to fill the plural number. The second light guiding groove 84a and the first light guiding groove 82c parallel to the first side 563 are used to fill the plurality of second light guiding grooves 84b to achieve the brightness and uniformity required for the development of the backlight module 102. Sexual requirements. The plurality of second light guiding grooves 84a, 84b are arranged with variable spacing and variable groove depth.

The design of the light guiding groove of the present invention is not limited to the light guiding plate, and can also be applied to the diffusing plate 58 or other optical substrates for guiding light.

Compared with the prior art, the first light guiding groove arranged radially is disposed on the optical substrate of the present invention, so as to be applied to a backlight module in which a single light source is turned into a light. Not only can the original light collecting characteristics of the light guiding groove be utilized, the brightness of the backlight module is increased, and the position of the first conductive light guiding groove is the same as that of the light source. The light emitted by the light source can be incident on the end of the backlight module along the first light guiding groove to solve the problem of bright and dark areas and achieve the uniformity of light output. At the same time, the successful development of a backlight module that meets the requirements of brightness and uniformity of a single light source can effectively reduce costs.

While the present invention has been described above by way of example, it is not intended to limit the invention, and the invention may be modified and modified without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

10, 20‧‧‧LED light source

12, 22‧‧‧Light guide plate

14, 24‧‧ ‧ light guide groove

16, 26‧‧ ‧ bright area

18, 28‧‧ dark areas

100‧‧‧ display device

102‧‧‧Backlight module

104‧‧‧LCD panel

52‧‧‧Light source

54‧‧‧reflector

56‧‧‧Light guide

58‧‧‧Diffuser

60, 62‧‧‧ pictures

522‧‧‧ axis

561‧‧‧ second side

563‧‧‧ first side

562‧‧‧Into the glossy surface

524, 524’ ‧ ‧ dots

564‧‧‧Glossy surface

82‧‧‧First light guide groove

82a-c‧‧‧First light guide groove

84, 84a-b‧‧‧ second light guiding groove

Figure 1A is a relative positional view of a prior art light guide plate and LED light source.

FIG. 1B is a light path diagram of the light emitted from the LED light source of FIG. 1A passing through the light guiding groove on the light guide plate.

Figure 2A is a relative positional view of the prior art light guide plate and LED light source.

FIG. 2B is a light path diagram of the light emitted by the LED light source of FIG. 2A passing through the light guiding groove on the light guide plate.

FIG. 3 is a schematic view showing a light collecting area of the light guide plate when the LED light source is disposed at a corner of the light guide plate.

FIG. 4 is a schematic view showing a light collecting area of the light guide plate when the LED light source is disposed at a corner of the light guide plate.

Fig. 5 is a schematic view showing the structure of a liquid crystal display device of the present invention.

Fig. 6A is a view showing the relative position of the light guide plate and the light source of the first embodiment of the present invention.

Fig. 6B is a view showing the relative position of the light guide plate and the light source of the second embodiment of the present invention.

Fig. 7 is a graph showing the relationship between the luminous intensity of the light source of the present invention and the angle of illumination.

Figure 8 is a graph showing the relationship between the pitch of the first light guiding groove and the angle of illumination of the present invention.

Figure 9 is a view showing the relative position of a light guide plate and a light source according to a third embodiment of the present invention.

52‧‧‧Light source

56‧‧‧Light guide

522‧‧‧ axis

524‧‧‧ dots

82‧‧‧First light guide groove

84a, 84b‧‧‧second light guiding groove

561‧‧‧ second side

563‧‧‧ first side

82a-c‧‧‧First light guide groove

Claims (18)

A backlight module is applicable to a liquid crystal display device, comprising: a light source disposed at a corner of the backlight module for generating a light, wherein the light source has a light emitting surface; and an optical substrate comprising a light output And a light incident surface disposed on a side of the optical substrate for receiving the light generated by the light source, the light emitting surface being disposed on a plane of the optical substrate corresponding to a liquid crystal display panel, The light is emitted from the optical substrate, and the light emitting surface has a plurality of first light guiding grooves for guiding the light received by the light incident surface, wherein the plurality of first light guiding grooves are centered at a center Radially arranged between a first side and a second side of the optical substrate, wherein a central axis of symmetry of the first side and the second side is a normal to a center of a light emitting surface of the light source, and a light intensity Is 1 on the central axis of symmetry and 1/2 on the first side and the second side, the center of the light from the center of the light emitting surface of the light source to the optical substrate The glossy surface is symmetric with the center The intersection of the axes is free to move on the central axis of symmetry. The backlight module of claim 1, wherein the light source is a light emitting diode. The backlight module of claim 1, wherein the light-emitting surface of the optical substrate is further provided with a plurality of second light guiding grooves for guiding the light received by the light-incident surface, the plurality of second The light guiding groove is parallel to the first side or the second side of the first light guiding groove. The backlight module of claim 3, wherein the plurality of second light guiding grooves are arranged with a variable pitch and a variable groove depth. The backlight module of claim 1, wherein the angle and the width of the cross section of each of the first light guiding grooves are adjusted according to the light emitting angle of the light source. The backlight module of claim 1, wherein the center of the light is a center point of the light emitting surface of the light source. The backlight module of claim 1, wherein the center of the circle is an intersection of a light incident surface of the optical substrate and the central axis of symmetry. The backlight module of claim 1, wherein the optical substrate comprises a light guide plate. The backlight module of claim 1, wherein the optical substrate comprises a diffusion plate. An optical substrate includes a light emitting surface and a light incident surface, wherein the light incident surface is disposed on one side of the optical substrate for receiving light generated by a light source, and the light emitting surface is disposed on a liquid crystal display panel. a plane of the optical substrate for emitting the light from the optical substrate, the optical substrate comprising: a plurality of first light guiding grooves disposed on the light emitting surface for guiding light received from the light incident surface, The plurality of first light guiding grooves are radially arranged in a center and distributed between a first side and a second side of the optical substrate, wherein a central axis of symmetry between the first side and the second side Is the normal of the center of the light-emitting surface of the light source, the light intensity is 1 on the central axis of symmetry and the light intensity on the first side and the second side is 1/2, the center of the circle A central point of the light emitting surface of the light source is freely movable between the intersection of the light incident surface of the optical substrate and the central axis of symmetry on the central axis of symmetry. The optical substrate of claim 10, wherein the light source is a light emitting diode. The optical substrate of claim 10, wherein the optical surface of the optical substrate is another a plurality of second light guiding grooves are provided for guiding the light received by the light incident surface, the plurality of second light guiding grooves being parallel to the first side of the first light guiding groove or the The second side. The optical substrate of claim 12, wherein the plurality of second light guiding grooves are arranged with a variable pitch and a variable groove depth. The optical substrate of claim 10, which is a light guide plate. An optical substrate according to claim 10, which is a diffusion plate. The optical substrate of claim 10, wherein an angle and a width of a cross section of each of the first light guiding grooves are adjusted according to an angle of illumination of the light source. The optical substrate of claim 10, wherein the center of the light is a center point of the light emitting surface of the light source. The optical substrate of claim 10, wherein the center of the circle is the intersection of the light incident surface of the optical substrate and the central axis of symmetry.