JPH1115411A - Liquid crystal display device and electronic device using the same - Google Patents

Abstract

(57) An object of the present invention is to provide an illuminating device arranged on the front of a display device, which uses a light guide plate for preventing generation of moire even in the case of dot matrix display, and a display device using the same. FIG. 2A shows a plan view of a display element and a display dot matrix. Dot pitch 41 is 240μ
m and the dot size 42 was 30 μm. Of course, the dot arrangement directions 43 and 44 are the end direction 4
5 or 46. FIG. 2B shows a state of the protrusion 32 of the light guide plate 31 of the lighting device. The arrangement directions 34 and 35 of the projections are not coincident with the direction 36 or 37 of the end side, and are shifted. This reduces moiré.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display device and an electronic apparatus using the same.

[0002]

2. Description of the Related Art Hitherto, an illuminating device arranged in front of a display device has been disclosed in Japanese Patent Laid-Open No. 6-324331.

[0003]

However, in the light guide plate of the conventional lighting device, a point-like light diffusion shape is formed on the surface, and the point-like light diffusion shape is arranged on a straight line in a predetermined pattern. In each case, the direction of the edge of the light guide plate and the arrangement direction of the point-like or rod-like light diffusing shapes coincided with each other.

[0004] As a result, moiré may occur depending on the dot pitch in the case of dot matrix display, although it is good in the case of the figure-eight segment display or the icon display. For this reason, the pitch of the point-like or rod-like light-diffusing shape has to be changed in accordance with the pitch at which moire does not easily occur at each dot pitch.

Accordingly, an object of the present invention is to solve such a problem, and an object of the present invention is to provide a light guide plate, an illuminating device, and a display device that prevent moire from occurring even in a dot matrix display.

[0006]

According to another aspect of the present invention, there is provided a display device comprising: a lighting device comprising a light source and a light guide plate; and a liquid crystal panel. A plurality of pixels formed by the light guide plate, a plurality of convex light scattering shapes are formed on the surface of the light guide plate on the side where the liquid crystal panel is arranged,
An arrangement direction of the light scattering shapes is arranged at a predetermined angle with respect to one side of the light guide plate, and is different from an arrangement direction of the pixels formed on the liquid crystal panel.

[0007] With the above configuration, it is possible to prevent moiré due to the influence of the arrangement of the light scattering shapes.
The display on the liquid crystal panel can be seen clearly.

Further, by arranging the light scattering shapes so as to intersect one side of the light guide plate within a range of 35 to 50 degrees, a clearer image can be obtained. More preferably, it is preferable that the light-scattering shapes are arranged at an angle of approximately 45 degrees with respect to one side of the light guide plate.

Further, by forming the light guide plate so that the pitch between the light scattering shapes becomes smaller as the distance from the side on which the light source is disposed becomes longer, uniform brightness is obtained over the entire screen. be able to.

Further, by mounting the above-described liquid crystal display device on an electronic device, an electronic device having excellent display quality can be obtained.

[0011]

Embodiments of the present invention will now be described with reference to the drawings.

(First Embodiment) FIG. 1 and FIG.
FIG. 1 is a diagram for explaining a liquid crystal display device according to a first embodiment of the present invention, FIG. 1 is an exploded sectional view, FIG. 2A is a plan view of a display element, and FIG. 2B is a plan view of a light guide plate.

Referring to FIG. 1, in a liquid crystal display device 10 of the present embodiment, a liquid crystal panel 20 is used as a display element.
You are using In the liquid crystal panel (or liquid crystal display element) 20, a liquid crystal 26 is sealed in a cell constituted by two glass substrates 21 and 22 and a sealing member 23. A transparent electrode 24 is provided on a lower surface of the glass substrate 21, and a transparent electrode 25 is provided on an upper surface of the glass substrate 22. As the transparent electrodes 24 and 25, ITO
(Indium Tin Oxide), tin oxide, or the like can be used. Polarizing plates 11 and 12 are provided outside the two glass substrates 21 and 22, respectively. Also, the lower polarizing plate 1
A reflection plate 15 is provided below 2.

On the upper side of the liquid crystal display element 20, a lighting device 3 is provided.
0 is provided. The lighting device 30 includes a light guide plate 31 and a light source 39. The light source 39 can receive light from the end face of the light guide plate 31. Light guide plate 31
Is formed of a transparent material having a refractive index of about 1.4 or more, for example, an inorganic transparent material such as an acrylic resin, a polycarbonate resin, an amorphous polyolefin resin, and glass, or a composite thereof.

Further, the light guide plate 31 has a columnar projection 32 on one surface. A plurality of such convex light diffusing shapes are regularly arranged in a predetermined direction. Light from the light source 39 enters from the end face of the light guide plate 31, and repeats total reflection in the light guide plate 31, and emits from the side surface of the protrusion 32. The size of the projection 32 is such that the wavelength of visible light is approximately 380.
Since it is from about nm to 700 nm, it is necessary to have a thickness of about 5 μm or more in order to prevent the influence of diffraction from occurring, and it is preferable that the projection 32 has a size of about 300 μm or less because the projection 32 has such a size that the naked eye does not matter. , Here 1
It was set to 00 μm. The column pitch 33 was 240 μm. The ratio between the height and the diameter of the cylinder of the projection 32 is 1: 1.
Is preferably about 1: 2, and here, it is 1: 2.
The thickness of the light guide plate 31 is desirably about 0.2 mm to about 10 mm, and is set to 1 mm here.

FIG. 2A shows a plan view of a display element and a display dot matrix. Dot pitch 41 is 240μ
m and the dot size 42 was 30 μm. Of course, the dot arrangement directions 43 and 44 are the end direction 4
5 or 46.

FIG. 2B shows a projection 32 of the light guide plate 31 of the lighting device.
Is shown. Projection alignment directions 34 and 35
Are shifted in a predetermined direction without being coincident with the direction 36 or 37 of the end side. The deviation angle 38 at this time was variously changed.

When the shift angle 38 is 0 degree, that is, when the projection arrangement directions 34 and 35 coincide with the end direction 36 or 37, moiré is noticeably generated. Deviation angle 38
As moire increases, moire decreases, from 35 degrees to 5
It is preferable to set the angle in the range of 0 degrees. More preferably, it became the smallest at 40 to 50 degrees.

Further, the pitch between the protrusions is reduced as the distance from the light source increases. By forming in this manner, a uniform display can be obtained at a location far from the light source as well as at a location near the light source.

(Second Embodiment) The dot pitch 41 of the display element according to the first embodiment of the present invention was changed to 200 μm.

Then, similarly to the first embodiment, as the displacement angle increases, the moire decreases, and this time the displacement angle 38
Is preferably set in the range of 35 degrees to 50 degrees.
More preferably, the moiré was reduced most around 35 to 45 degrees. Also in the present embodiment, the pitch of the protrusions is reduced as the distance from the light source increases. As in the first embodiment, uniform brightness can be applied to the liquid crystal panel side, and uniform display can be obtained over the entire liquid crystal panel.

(Third Embodiment) FIG. 3 is a plan view for explaining a light guide plate according to a third embodiment of the present invention.

The lighting device 3 according to the first embodiment of the present invention 3
The first protrusion 32 is changed from a point (column) to a rod (cube).
Changed to FIG. 3 shows a state of the protrusion 32 of the light guide plate 31 of the lighting device. The sectional view is the same as FIG. However,
The pitch of the projections is 150 μm. Protrusion alignment direction 13
4 is shifted without being coincident with the direction 137 of the end side. The deviation angle 138 at this time was variously changed. When the shift angle 138 is in the vicinity of 30 to 50 degrees, the moiré becomes small, and
Moire almost disappeared at around 5 degrees.

(Fourth Embodiment) As can be seen from the first embodiment and the second embodiment of the present invention, the corner 38 at which moire is most likely to occur differs depending on the dot pitch 41 of the display element. . Conversely, if the shift angle 38 is made different, moiré can be prevented at the dot pitch 41 of any display element. A method of manufacturing a light guide plate by cutting out a transparent plate with dot-like projections for the light guide plate of a lighting device.By changing the cut-out angle, it is possible to prevent moire against the dot pitch of various display elements. done.

(Fifth Embodiment) A plastic in which a point-like light diffusing shape is formed on the surface by an injection molding method and the point-like light diffusing shape is arranged on a straight line in a predetermined pattern. By rotating the master plate of the plate mold, the direction of the edge of the formed light guide plate and the direction in which the dot-shaped light diffusing shapes were arranged could be freely changed.

(Sixth Embodiment) The display element according to the first embodiment of the present invention is mounted on a mobile phone. An easy-to-read bright display without moiré was obtained.

Although the mobile phone has been exemplified in the embodiment of the present invention, the display element of the present invention can be used for various electronic devices such as home appliances, electronic organizers, and calculators.

(Seventh Embodiment) In the above-described embodiments, a cylinder is presented as the shape of a point-like light diffusing shape, but each embodiment has a hemispherical, conical, or prismatic shape. By forming the projections (convex portions), the same effects as in the above-described embodiment can be obtained.

[0029]

According to the present invention, as described above,
Moiré of the liquid crystal display device can be prevented, and an illuminated object such as a liquid crystal panel can be irradiated with light with uniform brightness.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a display device according to a first embodiment of the present invention, and is an exploded sectional view.

FIG. 2 is a diagram for explaining a display device according to a first embodiment of the present invention. FIG. 2A is a plan view of a display element, and FIG.
B is a plan view of the light guide plate of the lighting device.

FIG. 3 is a plan view illustrating a light guide plate according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Liquid crystal display device 11, 12 ... Polarizing plate 15 ... Reflection plate 20 ... Liquid crystal display element 21, 22 ... Glass substrate 26 ... Liquid crystal 30 ... Illumination device 31 ... Light guide plate 32 ... Protrusion 33 ... Cylinder pitch 34, 35 ... Conduction Arrangement direction of dot-like projections of light plate 36, 37 ... direction of edge of light guide plate 38 ... shift angle 39 ... light source 41 ... dot pitch 42 ... dot size 43, 44 ... arrangement direction of dots of display element 45, 46 ... Direction of display element edge

Claims (5)

[Claims] 1. A liquid crystal display device comprising a lighting device comprising a light source and a light guide plate, and a liquid crystal panel, wherein the liquid crystal panel has a plurality of pixels formed by electrodes, and the liquid crystal of the light guide plate is provided. A plurality of convex light scattering shapes are formed on the surface on which the panel is disposed, and the arrangement direction of the light scattering shapes has a predetermined angle with respect to one side of the light guide plate, and the liquid crystal A liquid crystal display device, which is different from an arrangement direction of the pixels formed on a panel. 2. The liquid crystal display device according to claim 1, wherein the arrangement direction of the light scattering shape crosses one side of the light guide plate in a range of 35 degrees to 50 degrees. 3. The liquid crystal display device according to claim 2, wherein the light scattering members are arranged at an angle of approximately 45 degrees with respect to one side of the light guide plate. 4. The liquid crystal display according to claim 1, wherein the pitch between the light scattering shapes decreases as the distance from the end face of the light guide plate on the side where the light source is disposed increases. apparatus. 5. An electronic apparatus comprising the liquid crystal display device.