CN1683966A - Light guide plate and back light module - Google Patents

Abstract

A light guide plate for a liquid crystal display device, the light guide plate includes a base plate, a triangular prism and a converging lens, the base plate includes a light exit surface and a bottom surface, the bottom surface is arranged opposite to the light exit surface, and the light guide plate also includes A triangular prism and a converging lens, the triangular prism includes an incident prism surface on the light incident side, the triangular prism is integrally formed with one end of the substrate, and the converging lens protrudes from the incident prism surface. The light guide plate of the present invention has high light coupling efficiency and uniform light emitting brightness.

Description

Light guide plate and backlight module

【Technical field】

The invention relates to a light guide plate and a backlight module used for a liquid crystal display device.

【Background technique】

Liquid crystal display devices are widely used in electronic equipment such as notebook computers, mobile phones, digital cameras, and electronic dictionaries due to their advantages of thinness, lightness, low power consumption, and low radiation. In recent years, with the continuous development of liquid crystal display technology and people's needs, higher requirements have been put forward for the brightness uniformity of liquid crystal display devices.

A prior art backlight module as shown in Figure 1, the backlight module 100 includes a light guide plate 10, a light source 11, a light source cover 12 and a reflector 13, the light guide plate 10 includes a light incident surface 14, A light emitting surface 15 and a bottom surface 16, the bottom surface 16 is a reflective surface, the reflective sheet 13 is arranged on one side of the bottom surface 16, and the light source 11 is arranged in the light source cover 12 on the light incident surface 14 side of the light guide plate 10 .

The backlight module 100 has the following defects, one: because the light guide plate 10 is a thin plate, relative to the diameter of the light source 11, the narrow light incident surface 14 of the light guide plate 10 can only make the light source 11 emit light directly toward the light guide plate 10 side. Less light enters, while other light needs to be reflected by the light source cover 12 at least once before entering the light guide plate 10, resulting in low efficiency of the light guide plate 10 coupling the light source 11 to emit light; second: the angle of light emitted by the light source 11 is different The light incident on the light guide plate 10 beyond a certain angle will directly exit from the light exit surface 15 adjacent to the light incident surface 14 to form a bright spot, thus resulting in uneven brightness of the backlight module 100 .

【Content of invention】

In order to overcome the problems of low light coupling efficiency and uneven brightness of the light guide plate in the prior art, the present invention provides a light guide plate with high light coupling efficiency and uniform brightness.

In order to overcome the problems of low optical coupling efficiency and uneven brightness of the prior art backlight module, the present invention further provides a backlight module using the above-mentioned light guide plate.

The technical solution adopted by the present invention to solve the technical problem is to provide a light guide plate, the light guide plate includes a base plate, a triangular prism and a converging lens, the base plate includes a light exit surface and a bottom surface, the bottom surface is opposite to the light exit surface The light guide plate also includes a triangular prism and a converging lens, the triangular prism includes an incident prism surface on the light incident side, the triangular prism is integrally formed with one end of the substrate, and the converging lens protrudes from the incident prism surface .

The technical solution adopted by the present invention to solve another technical problem is to provide a backlight module, the backlight module includes a light guide plate and a light source, the light guide plate includes a substrate, a triangular prism and a converging lens, the substrate It includes a light-emitting surface and a bottom surface, the bottom surface is opposite to the light-emitting surface, the light guide plate also includes a triangular prism and a converging lens, the triangular prism includes an incident prism surface on the light incident side, the triangular prism and the substrate One end is integrally formed, the converging lens protrudes from the surface of the incident prism, and the light source is opposite to the converging lens.

Compared with the prior art, the beneficial effects of the present invention are: the coupling area of the converging lens of the light guide plate of the present invention is larger, so its light coupling efficiency is high; the light guide plate of the present invention converts the light emitted by the light source into The collimated light enters the substrate through the triangular prism, conducts in the substrate, and finally emits uniformly from the light-emitting surface, so that the light-emitting brightness of the light guide plate is uniform.

【Description of drawings】

FIG. 1 is a schematic diagram of a prior art backlight module.

FIG. 2 is a schematic perspective view of the first embodiment of the light guide plate of the present invention.

Fig. 3 is a schematic diagram of the second embodiment of the light guide plate of the present invention.

FIG. 4 is a schematic diagram of a third embodiment of a light guide plate of the present invention.

FIG. 5 is a schematic diagram of a fourth embodiment of a light guide plate of the present invention.

Fig. 6 is a schematic diagram of a fifth embodiment of the light guide plate of the present invention.

FIG. 7 is a schematic diagram of the first embodiment of the backlight module of the present invention.

FIG. 8 is a schematic diagram of the second embodiment of the backlight module of the present invention.

FIG. 9 is a schematic diagram of a third embodiment of the backlight module of the present invention.

【Detailed ways】

Please refer to FIG. 2 , which is a three-dimensional schematic view of the first embodiment of the light guide plate of the present invention. The light guide plate 20 includes a substrate 21, a triangular prism 22, and a converging lens 23. The substrate 21 includes a light-emitting surface 211 and a bottom surface 212. The bottom surface 212 is opposite to the light-emitting surface 211. The light guide plate 20 also includes a Triangular prism 22 and a converging lens 23, the triangular prism 22 includes an incident prism surface on the light incident side, the triangular prism 22 is integrally formed with one end of the substrate 21, the converging lens 23 is semi-cylindrical, and the converging lens 23 protrudes It is arranged on the incident prism surface 225 . The substrate 21, the triangular prism 22 and the converging lens 23 are integrally formed. The length of the first side 221 of the triangular prism 22 is less than the length of the second side 222, and the first prism surface 223 and the second prism surface 224 where the first side 221 and the second side 222 are located are reflective surfaces, The vertex angle _θ1 formed by the intersection of the first side 221 and the second side 222 is an obtuse angle. The substrate 21 is a flat plate, the light emitting surface 211 includes a light pointing mechanism 213, the light pointing mechanism 213 is a prism array, and the bottom surface 212 is a reflective surface. In two opposite directions, a part of the incident prism surface 225 overlaps with a part of the light emitting surface 211 . The converging lens 23 protrudes from the center of the incident prism surface 225 of the triangular prism 22 .

The converging lens 23 has a large coupling area, so its light coupling efficiency is high. The light guide plate 20 converts the light emitted by the light source into collimated light through the converging lens 23, and the collimated light is totally reflected or reflected by the first prism surface 223 and the second prism surface 224 of the triangular prism 22 successively, and enters obliquely. The substrate 21, and conduct in the substrate 21 through the total reflection or reflection of the bottom surface 212, and finally pass through the light pointing mechanism 213 of the light-emitting surface 211 to uniformly emit from the light-emitting surface 211, so that the light-emitting brightness of the light guide plate 20 is uniform. .

Please refer to FIG. 3 , which is a schematic diagram of a second embodiment of the light guide plate of the present invention. The difference between the light guide plate 30 and the light guide plate 20 of the first embodiment is that the converging lens 33 is located on the incident prism surface 325 of the triangular prism 32, away from the substrate 31, and protrudes from a ridgeline to the direction of the substrate 31. .

Please refer to FIG. 4 , which is a schematic diagram of a third embodiment of the light guide plate of the present invention. The difference between the light guide plate 40 and the light guide plate 20 of the first embodiment is that the converging lens 43 intersects with one end surface of the substrate 41 on the incident prism surface 425 of the triangular prism 42 and extends away from the substrate 41. Highlight settings.

Please refer to FIG. 5 , which is a schematic diagram of a fourth embodiment of the light guide plate of the present invention. The light guide plate 50 is different from the light guide plate 20 of the first embodiment in that: the length of the first side 521 of the triangular prism 52 is greater than the length of the second side 522, and the first side 521 and the second side 522 are formed by the intersection of the first side 521 and the second side 522. The vertex angle θ ₂ is an acute angle, and a ridge line of the prism surface opposite to the vertex angle θ ₂ overlaps with an end line of the light-emitting surface 511 of the substrate 51, and the triangular prism 52 and the substrate 51 are located on the same side of the overlapping line, the The prism surface opposite to the apex angle _θ2 overlaps with a part of the light-emitting surface 511 , and the converging lens 53 protrudes from the incident prism surface where the first side 521 is located. The converging lens 53 has a large coupling area, so its optical coupling efficiency is high. The light guide plate 50 converts the light emitted by the light source into collimated light through the converging lens 53, and the collimated light enters the substrate 51 through the triangular prism 52, and is totally reflected or reflected on the substrate 51 by the bottom surface 512. Inner conduction, and finally pass through the light pointing mechanism 513 of the light-emitting surface 511 to make it uniformly emitted from the light-emitting surface 511, so that the light coupling efficiency of the light guide plate 50 is high, and the light-emitting brightness is uniform.

Please refer to FIG. 6 , which is a schematic diagram of a fifth embodiment of the light guide plate of the present invention. The light guide plate 60 is different from the light guide plate 50 of the fourth embodiment in that: the length of the first side 621 of the triangular prism 62 is equal to the length of the second side 622, and the first side 621 and the second side 622 intersect to form The apex angle θ ₃ is a right angle, and a ridge line of the prism surface opposite to the apex angle θ ₃ overlaps with an end line of the bottom surface 612, the triangular prism 62 and the substrate 61 are located on the same side of the overlapping line, and the second The side 622 intersects the light emitting surface 611 of the substrate 61 .

Please refer to FIG. 7 , which is a schematic view of the first embodiment of the backlight module of the present invention. The backlight module 700 includes a light guide plate 70 and a light source 701. The light guide plate 70 includes a substrate 71, a triangular prism 72 and a converging lens 73. The substrate 71 includes a light-emitting surface 711 and a bottom surface 712. The bottom surface 712 Set opposite to the light-emitting surface 711, the triangular prism 72 includes an incident prism surface 725 on the light incident side, the triangular prism 72 is integrally formed with one end of the substrate 71, and the converging lens 73 protrudes from the incident prism surface 725, The light source 701 is opposite to the converging lens 73 .

The substrate 71, the triangular prism 72 and the converging lens 73 are integrally formed. The length of the first side 721 of the triangular prism 72 is less than the length of the second side 722, and the two prism surfaces where the first side 721 and the second side 722 are located are reflective surfaces, the first side 721 and the second The vertex angle _θ4 formed by the intersection of the sides 722 is an obtuse angle. The substrate 71 is a flat plate, the light emitting surface 711 includes a light pointing mechanism 713, the light pointing mechanism 713 is a prism array, and the bottom surface 712 is a reflective surface. The converging lens 73 is semi-cylindrical, and a part of the light-emitting surface 711 overlaps a part of the incident prism surface 725 in two opposite directions. The converging lens 73 protrudes from the center of the incident prism surface of the triangular prism 72 . A reflection sheet 702 is disposed on one side of the bottom surface 712 . The light source 701 is a light emitting diode.

The two sides of the maximum luminous angle of the light source 701 are tangent to the cylindrical surface of the converging lens 73 at the same time, which can couple all the light emitted by the light source, so the light coupling efficiency is high. The light guide plate 70 converts the light emitted by the light source 701 into collimated light through the converging lens 73, and the collimated light passes through the two prism surfaces where the first side 721 and the second side 722 of the triangular prism 72 are located. total reflection or reflection, obliquely enter the substrate 71, and conduct in the substrate 71 through the total reflection or reflection of the bottom surface 712, and finally pass through the light pointing mechanism 713 of the light exit surface 711 to uniformly emit from the light exit surface 711, so that the guide The light emitting brightness of the light plate 70 is uniform. Therefore, the brightness of the light emitted by the backlight module 700 is uniform. The reflection sheet 702 reflects the light leaked from the bottom surface 712 back to the light guide plate 70 to improve light utilization efficiency.

Please refer to FIG. 8 , which is a schematic diagram of a second embodiment of the backlight module of the present invention. The difference between the backlight module 800 and the backlight module 700 of the first embodiment is that the light source 801 is a cold-cathode fluorescent lamp, and the cold-cathode fluorescent lamp is arranged in a light source cover 803, and the light source cover 803 and the light source 801 The opposite side is pasted or coated with a reflective film 804 . The reflective film 804 can reflect the light emitted by the light source 801 so that it passes through the converging lens 83 and the triangular prism 82 and enters the substrate 81 to improve light utilization efficiency.

Please refer to FIG. 9 , which is a schematic diagram of a third embodiment of the backlight module of the present invention. The difference between the backlight module 900 and the backlight module 700 of the first embodiment is that the first side 921 of the triangular prism 92 is longer than the second side 922, and the first side 921 intersects the second side 922. The formed vertex angle θ ₅ is an acute angle, and a ridge line of the prism surface opposite to the vertex angle θ ₅ overlaps with an end line of the light-emitting surface 911 of the substrate 91, and the triangular prism 92 and the substrate 91 are located on the same side of the overlapping line , the prism surface opposite to the apex angle θ ₅ overlaps with a part of the light-emitting surface 911 . The two sides of the maximum luminous angle of the light source 901 are tangent to the cylindrical surface of the converging lens 93 at the same time, which can couple all the light emitted by the light source, so the light coupling efficiency is high. The light guide plate 90 converts the light emitted by the light source 901 into collimated light through the converging lens 93, and the collimated light enters the substrate 91 through the triangular prism 92, and is totally reflected or reflected by the bottom surface 912. Conducted in the substrate 91 , and finally uniformly emitted from the light emitting surface 911 through the light pointing mechanism 913 of the light emitting surface 911 , so that the brightness of the light emitted by the backlight module 900 is uniform.

The light guide plate of the present invention is not limited to the description in this embodiment. For example, the converging lens of the light guide plate can also be hemispherical, and the light pointing mechanism can also be an array of cones, square cones, and hexagon cones. The backlight module of the present invention is not limited to the description in this embodiment, and the reflection sheet and the light guide plate can also be laminated together.

Claims (10)

1. A light guide plate, comprising a base plate, the base plate includes a light-emitting surface and a bottom surface, the bottom surface is arranged opposite to the light-emitting surface, it is characterized in that: the light guide plate also includes a triangular prism and a converging lens, the triangular prism It includes an incident prism surface on the light incident side, the triangular prism is integrally formed with one end of the substrate, and the converging lens is protrudingly arranged on the incident prism surface. 2. The light guide plate according to claim 1, wherein the substrate, the triangular prism and the converging lens are integrally formed. 3. The light guide plate according to claim 1, wherein the prism surface of the triangular prism connected with the incident prism surface is a reflective surface. 4. The light guide plate according to claim 1, wherein the incident prism surface partially overlaps the light emitting surface. 5 . The light guide plate according to claim 1 , wherein a prism surface of the triangular prism in contact with the incident prism surface overlaps a part of the light emitting surface. 6 . The light guide plate according to claim 1 , wherein a prism surface of the triangular prism that is in contact with the incident prism surface intersects the light emitting surface or the bottom surface. 7 . 7. The light guide plate according to claim 1, wherein the converging lens is semi-cylindrical or hemispherical. 8. The light guide plate according to claim 1, wherein the bottom surface is a reflective surface. 9. A backlight module, comprising a light guide plate and a light source, characterized in that: the light guide plate is the light guide plate described in any one of claims 1 to 8, and the light source is opposite to the converging lens set up. 10. The backlight module according to claim 9, wherein the light source is a light emitting diode or a cold cathode fluorescent lamp.

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