JPH04349403A - Light guide plate and plane type display device using the same - Google Patents

Abstract

PURPOSE:To increase the number of light guide grooves and make the pitch fine by providing plural optically separated light guide grooves in a transparent resin substrate by plural scattering and reflecting layers which are formed by laser light irradiation. CONSTITUTION:The inside of the plane plate substrate 1a made of transparent resin with a large refractive index is irradiated with the laser light having specific intensity by unidirectional specific-speed linear movement to form the white turbid scattering and reflecting layers 15 which extend in the thickness direction by the heat generation of the irradiation in parallel at equal intervals. The optically separated light guide grooves 2 are formed between the scattering and reflecting layers 15. When light is made incident on the end surfaces of the respectively light guide grooves, the light is reflected by the respective scattering and reflecting layers 15 to travel in the respective light guide grooves 2 without mutual interference.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate and a flat display device using the light guide plate.

0002

2. Description of the Related Art First, a conventional example of a light guide plate as a lighting device applied to a thin liquid crystal display device will be described with reference to FIGS. 3 and 4. 3 and 4, reference numeral 16 indicates a light guide plate as a whole, which is constructed by forming a scattering reflection layer pattern 17 on one surface of a parallel plate substrate (a transparent plate with a high refractive index such as an acrylic plate) 16a. be done. A light emitting body 1 such as a fluorescent lamp or a light emitting diode is placed on the end surface side of the light guide plate 16.
8 is arranged, and the light emitting body 18 is provided with a reflecting plate 19.

[0003]The light from the light emitter 18 is transmitted to the light guide plate 1.
Most of the incident light travels between both surfaces of the light guide plate 16 while repeating total reflection, and a part of the propagated light is scattered by the scattering reflection layer pattern 17. As shown in FIG. 4, the light is dispersed in all directions within the light guide plate 16. Then, a part of the light scattered by the scattering reflection layer pattern 17 is emitted from the upper surface of the light guide plate 16 to the outside.
The light enters the back glass plate of a liquid crystal display device (not shown) arranged above the light guide plate 16 as illumination light.

[0004] Conventionally, a transparent common electrode and a plurality of scanning stripe electrodes are formed on each opposing surface of a transparent front plate and a back plate that face each other, and a transparent common electrode and a plurality of scanning stripe electrodes are formed between the front plate and the back plate. It has a liquid crystal shutter device in which a liquid crystal layer is sealed, and a plurality of linear light sources whose emission is controlled by display signals are arranged on the back plate side of the device so as to intersect with a plurality of scanning stripe electrodes. A flat display device using the device as an optical shutter has been proposed.

[0005] Therefore, the present inventor developed a light guide plate suitable for application to such a flat display device (Japanese Patent Application No. 2-30011).
No. 9) was considered. The light guide plate of this prior example will be explained with reference to FIGS. 5 and 6. Parallel partition walls are formed at equal intervals on the support 4, and light guide grooves 2 made of rods of transparent synthetic resin with a high refractive index such as acrylic are provided between the partition walls. A barcode-shaped scattering reflection layer 15a is formed on the side surface of the rod 2 by chemical etching, printing, etc., and a support 4
A scattering reflection layer 15b made of white paint is provided on each partition wall and bottom of the
form. Further, on the upper side of the rod 2, a scattering and transmitting layer 5 is provided. A light emitting element such as a light emitting diode is arranged with each end face of each light guide groove 2 serving as a light entrance port 3, and each light emitting element is controlled by a display signal. According to such a light guide plate, the light incident on each end face of each light guide groove 2 travels through each light guide groove 2 without being interfered with each other, while repeating total reflection at the scattering reflection layers 15a and 15b. progress,
A part of the light passes through the scattering transmission layer 5 and is emitted toward the liquid crystal shutter device.

[0006]

[Problems to be Solved by the Invention] By the way, when applying the light guide plate explained in FIGS. 5 and 6 to the above-mentioned flat display device, in order to increase the display resolution, it is necessary to improve the light guide grooves of the light guide plate. In addition to increasing the number of holes, it is necessary to make the pitch considerably finer, but doing so will make manufacturing complicated and there is a risk that the dimensional accuracy will decrease. In view of these points, the present invention provides a light guide plate and such a light guide plate that can increase the number of light guide grooves, make the pitch of each light guide groove quite fine, and increase the dimensional accuracy. The purpose of this paper is to propose a flat-panel display device.

[0007]

[Means for Solving the Problems] A light guide plate according to the present invention includes:
A transparent resin substrate 1a has a plurality of light guide grooves 2 optically separated by a plurality of scattering/reflection layers 15 formed at predetermined intervals by laser beam irradiation.

In the flat display device according to the present invention, a common electrode 10 and a plurality of scanning stripe electrodes 12, which are both transparent, are formed on each opposing surface of a front plate 13A and a back plate 13B, which are both transparent. At the same time, the front plate 1
It has a liquid crystal shutter device 20 in which a liquid crystal layer 11 is sealed between the back plate 13A and the back plate 13B, and on the back plate 13B side, a plurality of lights are formed at predetermined intervals in the transparent resin substrate 1a by laser beam irradiation. A light guide plate 1 having a plurality of light guide grooves 2 optically separated by a scattering layer 15 is arranged so that the plurality of light guide grooves 2 intersect with a plurality of stripe electrodes 12, and each light guide plate 1 has Light emitting elements 6 whose light emission is controlled in accordance with display signals are arranged on the end faces of the optical grooves 2, respectively.

[0009]

[Operation] According to the light guide plate of the present invention, when light is incident on the end face of each light guide groove 2, it is reflected by each scattering reflection layer 15 and travels inside each light guide groove 2 without mutual interference. proceed.

According to the flat display device of the present invention, a predetermined voltage is sequentially and cyclically applied to the stripe electrodes 12, and
By supplying a display signal to each light emitting element 6, characters, figures, etc. can be displayed.

[0011]

[Embodiment] An embodiment of the light guide plate 1 according to the present invention will be described below with reference to FIG. A flat substrate 1a made of a transparent resin, particularly a transparent resin with a large refractive index, such as acrylic.
A plurality of cloudy scattering reflection layers 15 extending in the thickness direction arranged parallel to each other at a predetermined interval are arranged parallel to each other at equal intervals by heating by linearly moving irradiation of a laser beam of a predetermined intensity in one direction at a predetermined speed. and each scattering emitting layer 1
5, light guide grooves 2 are formed which are optically separated from each other. Note that a scattering and transmitting layer 22 is formed on the upper surface of the light guide plate 1, and a white scattering and reflecting layer 23 is formed on the lower surface.

Next, an embodiment of a flat display device (color flat display device) using such a light guide plate 1 will be described with reference to FIG. Reference numeral 20 indicates a liquid crystal shutter device, which includes a front glass plate 13A, a transparent common electrode 10 deposited over substantially the front surface of the lower surface of the front glass plate 13A, and a rear glass plate 13B.
, transparent stripe electrodes 12 of equal width arranged at equal intervals on the upper surface thereof, and a liquid crystal shutter device 11 arranged between the common electrode 10 and the stripe electrodes 10. Note that 14 indicates a liquid crystal drive circuit that applies a scanning voltage to the stripe electrodes 12 of the liquid crystal shutter device 20.

Reference numeral 1 denotes a light guide plate shown in FIG. 1, in which a plurality of light guide grooves 2 are arranged on a back glass plate 13 such that they intersect obliquely, in this case orthogonally, with the stripe electrodes 12 of the liquid crystal shutter device 20.
It is placed on the bottom surface of B. A light emitting element 6 consisting of red, green, and blue LEDs (fluorescent display elements, plasma display elements, etc. can also be used) is disposed on one end surface of each light guide groove 2 of this light guide plate 1, and each optically It is shielded by the shielding plate 7,
This is done so that no interference of light occurs between the respective light guide grooves 2. 8 is a light emitting element drive circuit that supplies red, green, and blue display signals to each of the light emitting elements 6, and the display data signal from the display data signal source is supplied to the light emitting element drive circuit 8 and sampled and held. be synchronized.

By sequentially and cyclically supplying voltage to the stripe electrodes 12, the portions of the liquid crystal layer 11 corresponding to the stripe electrodes 12 become transparent one after another, and the selection of red, green, and blue light emitting elements is performed. When the target is turned on, the light guiding groove 2 emits light in a striped pattern, thereby displaying characters, figures, etc. in color.

[0015]

According to the above-described light guide plate of the present invention, a plurality of light guide grooves optically separated by a plurality of scattering and reflecting layers formed at predetermined intervals by laser beam irradiation are formed in a transparent resin substrate. As a result, it is possible to obtain a light guide plate in which the number of light guide grooves can be increased, the pitch of each light guide groove can be made extremely fine, and dimensional accuracy can be increased. .

According to the flat panel display device of the present invention, a transparent common electrode and a plurality of scanning stripe electrodes are formed on each opposing surface of the transparent front plate and rear plate, respectively, and It has a liquid crystal shutter device in which a liquid crystal layer is sealed between a front plate and a back plate, and on the back plate side, optical information is provided by a plurality of light scattering layers formed at predetermined intervals in a transparent resin substrate by irradiation with laser light. A light guide plate having a plurality of light guide grooves separated from each other is arranged so that the plurality of light guide grooves intersect with a plurality of stripe electrodes, and a display signal is provided on the end surface side of each light guide groove of the light guide plate. Since light emitting elements whose light emission is controlled accordingly are arranged, the number of light guide grooves in the light guide plate can be increased, and the pitch of each light guide groove can be made quite fine, and dimensional accuracy can be increased. Therefore, a flat display device with high display resolution can be obtained.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a light guide plate according to an embodiment of the present invention.

[Figure 2]
An exploded perspective view showing a liquid crystal shutter device according to an embodiment of the present invention

[Figure 3] Cross-sectional view showing a conventional light guide plate

[Figure 4] An explanatory diagram of the diffusion of incident light in the conventional light guide plate in Figure 3.

[
Figure 5: Perspective view of a prior example light guide groove type light guide plate

[Fig. 6] An exploded perspective view of the light guide groove type light guide plate of the prior example shown in Fig. 5.

[Explanation of symbols]

1 Light guide plate 1a Board 2 Light guide groove 3 Inlet port 6 Light emitting element 7 Shielding plate 8 Light emitting element drive circuit 9 Display data signal source 10 Common electrode 11 Liquid crystal layer 12 Stripe electrode 13A Front glass plate 13B Rear glass plate 14 Liquid crystal drive circuit 15 Scattering reflective layer 20 Liquid crystal shutter device 22 Scattering transparent layer 23 Scattering reflective layer

Claims (2)

[Claims] 1. A light guide plate comprising a plurality of light guide grooves optically separated by a plurality of light scattering and reflective layers formed at predetermined intervals by laser beam irradiation in a transparent resin substrate. 2. A common electrode and a plurality of scanning stripe electrodes, which are both transparent, are formed on each opposing surface of a front plate and a back plate, which are both transparent, and are formed between the front plate and the back plate. The device has a liquid crystal shutter device in which a liquid crystal layer is sealed in the back plate, and is optically separated by a plurality of scattering and reflecting layers formed at predetermined intervals in a transparent resin substrate by laser beam irradiation. A light guide plate having a plurality of light guide grooves is disposed such that the plurality of light guide grooves intersect with the plurality of striped electrodes, and light is emitted on the end surface side of each light guide groove of the light guide plate in accordance with a display signal. 1. A flat display device characterized by disposing a light emitting element that is controlled.