CN1580899A - Backlight module and its light guide plate - Google Patents

Abstract

The invention discloses a backlight module and a light guide plate thereof. The backlight module includes a light guide plate and a plurality of point light sources, the light guide plate includes a light incident surface, a light exit surface intersecting the light incident surface, and a bottom surface opposite to the light exit surface, the multiple point light sources are arranged corresponding to the light incident surface, And the area where the light incident surface is coupled with the point light source forms multiple refraction and scattering fine lines. The invention can reduce the incident dark zone of the light guide plate, so that the light guide plate and the backlight module adopting the light guide plate have higher light output uniformity.

Description

Backlight module and its light guide plate

【Technical field】

The invention relates to a backlight module and a light guide plate thereof, in particular to a light guide plate with high light uniformity and a backlight module using the light guide plate.

【Background technique】

Due to the advantages of lightness, thinness, and low power consumption, liquid crystal displays are widely used in modern information equipment such as notebook computers, mobile phones, and personal digital assistants. Because the liquid crystal itself does not have light-emitting properties, it needs to be provided with a backlight module to realize the display function.

The prior art backlight module includes a light source and a light guide plate. The light source is arranged relative to the light incident surface of the light guide plate. The light guide plate guides the transmission direction of the light beam emitted from the light source, and converts the line light source or point light source into a surface light source to emit. A plurality of dots are distributed on the bottom surface of the light guide plate to destroy the total reflection condition of the light beam transmitted inside the light guide plate and scatter them to improve the uniformity of the light beam emitted from the light guide plate, thereby improving the overall performance of the backlight module. The density and size of the dots can be designed in different ways to suit different backlight modules.

Refer to FIG. 1 for a prior art backlight module. The backlight module 9 is composed of a light guide plate 10 , a translucent material plate 20 , a reflective material box 30 and a light source 40 . The translucent material plate 20 is stacked on the light guide plate 10, and the periphery and the bottom surface 12 of the light guide plate 10 are contained in the reflective material box 30, and a positioning groove 31 for accommodating the light source 40 is provided on one side of the reflective material box 30. . When working, the light beam emitted by the light source 40 is incident from one side of the light guide plate 10, and after being acted on by the gradient wave pattern on the bottom surface 12 of the light guide plate 10 and the light-reflecting material box 30, a plane light is generated, and emerges from the light exit surface 11 of the light guide plate 10 , the translucent material plate 20 makes the plane light distribution more uniform.

Please also refer to FIG. 2, since the light source 40 has a certain emission angle, such as a light emitting diode, the emission angle can be 30 to 130 degrees, and the side of the light guide plate 10 opposite to the light source 40 is a plane, so that the light beam emitted by the light source 40 passes through the After entering the light guide plate 10 after side refraction, the divergence angle will be further reduced, and the maximum is about 119.653 degrees, so that a large dark band 13 will be generated on the incident side of the light guide plate 10, thereby reducing the utilization rate of the light beam, affecting the backlight module 9 and even the use of the light guide plate 10. The luminance and light uniformity of the liquid crystal display of the backlight module 9 .

Referring to FIG. 3 , Taiwan Patent No. 530,919 published on May 1, 2003 discloses a backlight module capable of reducing the incident dark area of the light guide plate. The backlight module is provided with a plurality of concave holes 50 on the light guide plate 3 , and the plurality of concave holes 50 are arranged in a row directly in front of the incident point 2 of the point light source. A series of multiple concave holes 50 are respectively arranged in front of the incident point 2 of each point light source. The multiple concave holes 50 can penetrate the light guide plate 3, and when the incident light touches the outer edge of the concave hole 50, a light refraction or total light reflection effect is generated. It can destroy the strong optical directivity of the point light source and increase the light divergence angle, which helps to improve the defect of the dark area on the incident side of the light guide plate 3 .

However, the concave hole 50 is arranged near the light-incident surface of the light guide plate 3, and the light total reflection effect that occurs when the incident light touches the surface causes part of the incident light that has entered the light guide plate 3 to be reflected back, and the amount of light that continues to be transmitted toward the inside of the light guide plate 3 reduce the light utilization rate and the luminance of the backlight module; and, the plurality of concave holes 50 are formed inside the light guide plate 3, and the refraction and reflection of the light on the surface of the concave holes 50 cause the energy loss of the light rays that have entered the light guide plate. In addition, the refractive index of the concave hole 50 is different from the refractive index of the light guide plate 3, which hinders the in-depth transmission of the incident light. The light intensity of the smaller area surrounded by the concave hole 50 is stronger, and the other larger areas are due to the energy of the incident light. Factors such as reduction, obstruction of the concave hole 50 and loss of scattering energy make the light intensity transmitted to the larger area weaker, which affects the uniformity and luminance of the light emitted by the light guide plate.

【Content of invention】

In order to overcome the defect of low light output uniformity of the prior art backlight system, the present invention provides a backlight module with high light output uniformity.

The invention also provides a light guide plate with high light uniformity.

The technical solution of the present invention to solve the technical problem is to provide a backlight module, including a light guide plate and a point light source, the light guide plate includes a light incident surface, a light exit surface intersecting the light incident surface, and a bottom surface opposite to the light exit surface, The point light source is arranged corresponding to the light incident surface, and the area where the light incident surface is coupled with the point light source has a plurality of refraction and scattering fine lines.

The present invention also provides a light guide plate with high uniformity of light output. The light guide plate is used to cooperate with a point light source, and includes a light incident surface for receiving a light beam, a light exit surface intersecting with the light incident surface and guiding the light beam to exit, and a light exit surface connected to the light exit surface. The opposite bottom surface, and the area where the light incident surface is coupled with the point light source has multiple refraction and scattering fine lines.

Compared with the prior art, the beneficial effect of the present invention is that since the area where the light incident surface of the light guide plate of the present invention is coupled with the point light source forms a plurality of refraction and scattering fine lines, the fine lines can use the principle of refraction to divert the light beam emitted by the point light source. The divergence angle of the light guide plate is expanded on both sides, and at the same time, the scattering principle is used to disperse the light beams with a relatively concentrated luminous range, so as to reduce or even eliminate the incident dark band phenomenon of the light guide plate, so that the light guide plate and the backlight module using the light guide plate have higher uniformity of light output.

【Description of drawings】

FIG. 1 is an exploded perspective view of a prior art backlight module.

FIG. 2 is a schematic diagram of part of the optical path of the prior art backlight module shown in FIG. 1 .

Fig. 3 is a plan view of another prior art backlight module.

FIG. 4 is a perspective view of the first embodiment of the backlight module of the present invention.

FIG. 5 is a schematic diagram of dot distribution of the backlight module shown in FIG. 4 .

FIG. 6 is a perspective view of the second embodiment of the backlight module of the present invention.

FIG. 7 is a perspective view of a third embodiment of the backlight module of the present invention.

【Detailed ways】

Please refer to FIG. 4 , which is the first embodiment of the backlight module of the present invention. The backlight module 200 includes a plurality of point light sources 210 and a light guide plate 220 . The point light source 210 emits light beams, and the light guide plate 220 guides the transmission direction of the light beams emitted by the point light sources 210 to convert them into surface light sources to emit.

The point light source 210 can be a light emitting diode or a small light bulb. And the required display color and luminance can be adjusted by configuring multiple light-emitting diodes or small light bulbs of different colors.

Please refer to FIG. 5 together. The light guide plate 220 is flat and made of transparent materials such as acrylic, glass or polycarbonate. It includes a light incident surface 221 and a light exit surface 224 connected to the light incident surface 221. , a bottom surface 223 and a side surface 225 opposite to the light emitting surface 224 .

The light incident surface 221 receives the light beam emitted by the point light source 210, and a plurality of arc-shaped grooves (not marked) are arranged on the area where the light beam emitted by the point light source 210 is coupled, and there is a certain distance between adjacent arc-shaped grooves . In order to reduce the incident dark band, the light incident surface 221 is coupled to the arc-shaped groove area of the point light source 210 to form a plurality of refraction and scattering fine lines 222, and the refraction and scattering fine lines 222 are formed perpendicular to The light guide plate 220 is ground in the direction of the light exiting surface. The depth and disorder of the refraction and scattering fine lines 222 vary with the specifications of tools such as grinding wheels, which affect the degree of light refraction and scattering. The plurality of refraction and scattering fine lines 222 can be evenly distributed in the arc-shaped groove. The refraction and scattering fine lines 222 use the principle of refraction to expand the divergence angle of the beam emitted by the point light source 210 to both sides of the light guide plate 220, and at the same time use the principle of scattering to disperse the light beam that originally had a relatively concentrated luminous range, so as to reduce or even eliminate the incident darkness of the light guide plate. belt phenomenon.

The light emitting surface 224 can be processed into a rough surface with a certain roughness. The bottom surface 223 of the light guide plate 220 is provided with a plurality of dots 23 to improve the luminance and uniformity of the light beam emitted from the light guide plate 220 . The size of the dots 23 increases along the direction away from the light incident surface 221 , and they are cylindrical. Certainly, the dots 23 may also be in the shape of a sphere, a cube, a pyramid or other suitable shapes. The dots 23 can be distributed on the bottom surface 223 of the light guide plate 220 by printing or injection molding. In addition, a plurality of V-shaped grooves (not shown) may also be provided on the bottom surface 223 to replace the plurality of dots 23 . The bottom surface 223 of the light guide plate 220 can be provided with a reflective film (not shown), the reflective film is a multi-layer thin film formed alternately by SiO ₂ and TiO ₂ to reflect the light beam projected on it, so as to prevent the light beam from passing through the light guide plate 220. The bottom surface 223 of the light guide plate escapes, thereby reducing the energy loss of the light beam and improving the overall optical performance of the light guide plate 220 . The reflective film can be formed by methods such as chemical vapor deposition, electron beam evaporation, sputtering, etc., and its reflectivity in the visible light region can reach more than 98%.

Of course, the arc-shaped grooves can also be arranged continuously. The arc-shaped groove can be integrally formed with the light guide plate 220 , or can be formed by machining.

Please refer to FIG. 6 , which is a second embodiment of the backlight module of the present invention. The backlight module 300 includes a plurality of point light sources 310 and a light guide plate 320 . The light guide plate 320 is flat, and of course it can be a wedge-shaped light guide plate, including a light incident surface 321, a bottom surface 323 intersecting the light incident surface 321, a light exit surface 324, and a side surface 325. The point light source 310 faces the light incident surface 321 set up.

The light incident surface 321 is a plane, on which a plurality of refraction and scattering fine lines 322 are formed in the area corresponding to the light emitting range of the point light source 310, the refraction and scattering fine lines 322 are perpendicular to the light exit surface 324 of the light guide plate 320, and have a certain depth and chaos. A plurality of dots 33 are distributed on the bottom surface 323 , and the size and density of the dots 33 gradually increase along the direction away from the light incident surface 321 , so as to improve the uniformity of light emitted from the light guide plate 320 and the backlight module 300 .

Please refer to FIG. 7 , which is the third embodiment of the backlight module of the present invention. The backlight module 400 includes a plurality of point light sources 410 and a light guide plate 420 . The light guide plate 420 is flat and includes two light incident surfaces 421 , a bottom surface 423 vertically connected to the light incident surfaces 421 , a light exit surface 424 and side surfaces 425 . The point light source 410 is disposed opposite to the two light incident surfaces 421 .

The areas where the two light incident surfaces 421 are coupled with the point light source 410 are recessed inward to form a V-shaped groove (not shown), so as to fix the point light source 410 and make good coupling with the light path. The V-shaped groove is provided with a plurality of refraction and scattering fine lines 422. The refraction and scattering fine lines 422 use the refraction principle to expand the divergence angle of the light beam emitted by the point light source 410 to both sides of the light guide plate 420, and use the scattering principle to make the original luminous range relatively wider. The concentrated light beam is dispersed to reduce or even eliminate the incident dark band phenomenon of the light guide plate.

A plurality of dots 43 are distributed on the bottom surface 423 . The plurality of dots 43 are evenly distributed on the bottom surface 423 of the light guide plate 420 , and are in the shape of a cylinder, or a cube, a truncated cone, a sphere or a rectangle. The bottom surface 423 of the light guide plate 420 has a reflective film (not shown) to prevent the light beam from escaping from the bottom surface 423 of the light guide plate 420 , thereby reducing the energy loss of the light beam and improving the overall optical performance of the light guide plate 420 . Of course, a reflective plate (not shown) may also be provided on a side adjacent to the bottom surface 423 of the light guide plate 420 to realize this function.

Claims (10)

1. A backlight module comprising a point light source and a light guide plate, the light guide plate comprising a light incident surface, a light exit surface intersected with the light incident surface and a bottom surface opposite to the light exit surface, the point light source is arranged corresponding to the light incident surface, It is characterized in that the area where the light incident surface is coupled with the point light source has multiple refraction and scattering fine lines. 2. The backlight module according to claim 1, wherein the area where the light incident surface is coupled with the point light source is recessed inward to form an arc-shaped groove. 3. The backlight module as claimed in claim 2, wherein there is a distance between the arc-shaped grooves. 4. The backlight module according to claim 1, wherein the area where the light incident surface is coupled with the point light source is recessed inward to form a V-shaped groove. 5. The backlight module according to claim 1, wherein the area where the light incident surface is coupled with the point light source is a plane. 6. The backlight module as claimed in claim 1, wherein the plurality of refraction and scattering fine lines are perpendicular to the light emitting surface of the light guide plate. 7. The backlight module as claimed in claim 1, wherein the plurality of refraction and scattering fine lines have depth and disorder, and the depth and disorder correspond to the degree of light refraction and scattering. 8. The backlight module as claimed in claim 7, wherein the plurality of refraction and scattering fine lines are evenly distributed. 9. The backlight module according to claim 1, wherein the point light sources are light emitting diodes. 10. A light guide plate used to cooperate with a point light source, comprising a light incident surface for receiving a light beam, a light exit surface intersecting with the light incident surface and used to guide the light beam to exit, and a bottom surface opposite to the light exit surface, characterized in that: The region where the light incident surface is coupled with the point light source has a plurality of refraction and scattering fine lines.

Images