JP2755541B2 - Liquid crystal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display.
More specifically, even when a large number of liquid crystal display modules are arranged to form a large display screen, the pixel (hereinafter referred to as "dot") pitch of the joints of the liquid crystal display module is made small and equal to the dot pitch at the center. Accordingly, the present invention relates to a liquid crystal display device having improved image quality during large-screen display and scroll display.

[0002]

2. Description of the Related Art In order to form a large screen in a liquid crystal display device, as shown in FIG. 5, a drive circuit board is provided on a liquid crystal display panel 51 composed of a transparent substrate sandwiching a liquid crystal material.
A configuration is considered in which a plurality of liquid crystal display modules 50 provided with 52 are arranged side by side, and a light source 53 is provided on the back side. On the other hand, in each liquid crystal display panel 51, a bonding seal portion 54 for enclosing a liquid crystal material is formed around the substrate (see FIG. 6), and this portion is a non-display portion that does not function as a display portion. Accordingly, in this case, as shown in FIG. 6, the dot pitch X that straddles the seal portion 54 from the pitches Xa and Ya of the dots 55 of the effective display portion in each module 50.
b and Yb become large and the pitch becomes non-uniform. If scroll display is performed as it is, the adjacent liquid crystal display panel 51
Characters related to the dot pitches Xb and Yb at the seam portion are interrupted and difficult to see, thereby deteriorating the image quality. If Xa = Xb and Ya = Yb are set to eliminate the non-uniformity, the dot pitch becomes large as a whole and the aperture ratio becomes extremely small.

When the aperture ratio is set to 70% or more in order to actually obtain good display performance, the dot widths Xd and Yd are set to
It is necessary to make each of the distances Xp and Yp of the module 55 about 6 times or more.
Since the distances Xs and Ys can be reduced only to about 1.5 mm (typically 2 to 4 mm), the dot widths Xd and Yd become 18 mm or more as described below.

Xd> 6Xp = 6 × (2Xs) = 18 mm Yd> 6Yp = 6 × (2Ys) = 18 mm

[0005]

As described above, in a large-screen liquid crystal display device using a conventional liquid crystal display module, the dot pitch becomes non-uniform. It was necessary to increase the area and the interval between dots. As a result, when a large-capacity display is performed, there is a problem that the size becomes very large. For example, when a screen of 256 × 256 dots is formed, if the dot pitch is set to 21 mm from the necessity of 18 mm or more, the size becomes about 5 m square.

[0006] Further, in the scroll display, since the joint portion between the liquid crystal display modules becomes a non-display area in a wide range, the screen becomes very difficult to see.

In order to solve such a problem, a liquid crystal display module 45 as shown in FIG. 4 in which the dot pitch is made small and uniform and the aperture ratio is improved can be considered. FIG.
, Polarizing plates 42a and 42b are provided outside the two transparent substrates 41a and 41b, respectively, and an illumination lamp 44 is placed on the side opposite to the display surface side. Light guide plate 43 provided on the display surface side
The light projected from each dot 47 is refracted by the light guide section 48 and projected so as to spread in the peripheral direction of the liquid crystal display module, so that in the antireflection film 46 on the surface of the light guide plate, near the periphery of each module. Dots are projected.
As a result, the width of the connected portion of the periphery of the module that can be visually recognized can be made relatively narrower than the width of the dot, and the aperture ratio is improved. Therefore, by changing the dimensions of the light guide plate,
Since the width of the connecting portion of the module on the surface can be adjusted, the dot pitch over the entire screen can be easily made uniform without increasing the dot width and the dot pitch.

However, since the thickness of the light guide plate is 2 mm or more and the shape of the light guide portion is obliquely provided, it is difficult to manufacture, and it is not possible to use techniques such as injection molding. Absent.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and has a small dot pitch and is equivalent to the dot pitch of an effective display section, thereby improving image quality in large-screen display and scroll display. It is another object of the present invention to provide a liquid crystal display device which can be mass-produced at low cost.

[0010]

According to the liquid crystal display device of the present invention, two transparent substrates each having a transparent electrode which can be driven for each pixel are formed, and the two transparent substrates are held at a constant gap. A sealing portion to be adhered, a liquid crystal material filled in a gap between the two transparent substrates, a polarizing plate disposed outside each of the two transparent substrates, and a polarizing plate disposed on a side opposite to a display surface of the transparent substrate. A light guide plate having a hole for guiding light of each pixel on the display surface side of the transparent substrate, wherein the hole communicates with the light guide portion. It is characterized in that it is formed by laminating a plurality of sheets.

[0011]

According to the liquid crystal display device of the present invention, the light emitted from each dot is guided by the light guide portion of the light guide plate provided on the surface thereof and projected so as to spread in the peripheral direction of the liquid crystal display module. . As a result, the width of the non-display area at the joint portion of the module periphery that can be visually recognized can be made relatively narrower than the dot width, and the aperture ratio is improved. Moreover, since the light guide plate is formed by stacking a plurality of thin plates having holes provided in a matrix, the shape and size of the holes provided in each of the thin plates can be arbitrarily changed, and any light guide can be provided. The part can be easily formed. Therefore, the dot pitch can be easily made uniform over the entire screen without increasing the dot width and the dot pitch, the image quality to be displayed is improved, and large-capacity display and scroll display can be performed with a relatively small size. .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a liquid crystal display device according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a sectional view of a main part of a module of an embodiment of the liquid crystal display device of the present invention. FIG. 2 is a schematic plan view showing dots on a display screen of a liquid crystal display device formed by arranging a plurality of modules of FIG. 3 is a partially enlarged view of FIG.

In FIG. 1, reference numerals 1a and 1b denote transparent substrates such as a glass substrate provided with a transparent electrode which can be driven for each pixel, and are adhered at regular intervals by a seal portion 11 provided around the substrate. Liquid crystal material is filled, and polarizing plates 2a and 2b are provided on both outer sides. The light guide plate 3 is provided on the surface of the polarizing plate 2a on the display surface side.
The holes a, 3b,... are stacked so as to communicate with each other, and a light guide portion 8 for each dot is formed. The liquid crystal display module 5 is configured by disposing a backlight 4 on the back surface and, if necessary, a drive circuit board (not shown) for driving each dot.

It is to be noted that an anti-reflection film 6 made by applying anti-reflection treatment to the surface of vinyl chloride, acrylic, polycarbonate or the like is provided on the surface of the light guide mask 3 which is a laminate of the light guide plates 3a, 3b. Thereby, surface reflection can be prevented and visibility characteristics can be improved.

As shown in the sectional view of FIG. 1, the light guide mask 3 has a light guide portion 8 having a light transmitting property for each dot 7 formed by a transparent electrode film provided on the transparent substrates 1a and 1b. It has a shape arranged in a grid by the lattice-shaped light-shielding portions 9. The light guide section 8 guides the display area of each dot formed on the transparent substrate 1a to the outer peripheral end side of the display panel by a frame-shaped light shielding section 9, and the light transmitted on the transparent substrate 1a. Is projected onto the anti-reflection film 6 through the light guide section 8, and when viewed from the surface of the anti-reflection film, it can be seen that each dot is displayed on the anti-reflection film.

As described above, the display area on the transparent substrate is narrow due to the presence of the seal portion 11 on the periphery, but can be used up to the outer peripheral edge on the antireflection film. It can be.

The shape of the light guide portion 8 is not particularly limited to a square shape, and may be, for example, a circular shape, a hexagonal shape such as a honeycomb shape, or another polygonal shape. Any shape can be selected while taking into account.

The light guide mask 3 is formed of, for example, a plastic material, a metal plate, glass, or the like. For example, when the display section forms a 24 × 24 dot with a liquid crystal display module of 10 cm × 10 cm, the light guide mask 3 The length of the part (the thickness of the light guide mask) is formed to be about 5 to 10 mm, and the width of the light shielding part 9 is about 1 mm
The area of the light guide is about 3 mm, which is almost the same as the size of the dot.
The size is about 3 mm.

The thickness of the thin plate constituting the light guide mask 3 is d,
The number of sheets is n, and the size of the hole 10 in the nth thin plate counted from the side opposite to the display surface is _Pn . In this embodiment, d =
The light guide mask 3 was 0.4 mm, n = 12 and the thickness of the light guide mask 3 was 4.8 mm. However, d is generally 0.1 to 2.0 mm, and n is preferably about 5 to 20.

The holes of each light guide plate are formed by punching with a die, forming a mold of plastics or the like, or forming a resist film only in a non-display area, and then etching with a hydrofluoric acid or chlorine-based etchant.

At this time, the holes of the lowermost panel 3a correspond to the dots 7 of the liquid crystal display element module. In the uppermost panel 3m, the effective display area of the module is the transparent substrate 2a.
The hole is provided at a position where the display can be enlarged to the entire area of the display. In the light guide plates 3b to 3k in the intermediate layer, holes having openings slightly larger than the holes in the light guide plate in the lower layer are provided so as to be sequentially shifted to the outer peripheral side of the light guide plate and communicate with each other.

Furthermore, when the holes provided in the thin plate are tapered to increase the opening area on the display surface side, the side surfaces of each hole of the adjacent thin plate become continuous, and scattering of light in the light guide portion is prevented. Thus, light transmission loss can be reduced. The taper angle θ between the vertical direction (see FIG. 1) is 0 ° to 10 °
Is preferred. In this case, a tapered hole is formed by a method such as molding or NC processing.

In order to dispose the light guide mask 3 on the liquid crystal display panel, the outer frame of the light guide mask 3 and the liquid crystal display are so aligned that the light guide 8 of the light guide mask 3 and each dot of the liquid crystal display panel match. Align and adhere to the outer frame of the panel.

The anti-reflection film 6 is the same as that used for a liquid crystal display device usually used in a bright place, and is surface-treated so as not to reflect external light.
For example, a plastic plate or the like that has been subjected to a non-glare treatment and has a roughened surface can be used. Also,
An antireflection film may be formed by a multilayer coating. The antireflection film functions as a screen, and the light of each dot emitted from the transparent substrate 1a is projected and displayed. This antireflection film 6 is preferable for improving display characteristics, but is not necessarily essential to the present invention.

The light emitted from the backlight 4 passes through only the dots selected by the transparent electrode film and enters the corresponding light guide 8, thereby being projected on the surface of the antireflection film 6. In this case, by increasing as it approaches the opening area of the holes 10 on the display surface side, i.e., the opening by the P _n described above and _{P n> P n-1>} ‥‥‥> P 2> P 1 The display area can be extended to the peripheral edge portion by improving the efficiency and sequentially moving the holes formed in the thin plate toward the outer peripheral side. Therefore, as shown in FIG. 2, even when a large screen is formed by arranging a plurality of the liquid crystal display modules 5, an image is enlarged to the connection side of the liquid crystal display module 5. As a result, in the image displayed on the surface of the light guide mask 3, the seal portion 54, which is a non-display portion shown in the related art, is used.
(See FIG. 6), but in an extremely narrow state as shown in FIG.

As described above, in the liquid crystal display device according to the present invention, a non-display portion such as a seal portion at the periphery can be freely reduced, so that the dot pitches Xb, Yb as shown in FIG.
Even if b is not enlarged, the dot pitch can be made uniform at the joint portion between the center portion and the peripheral portion of the panel. That is,
In FIG. 3, Xa = Xb and Ya = Yb can be set.

If the above liquid crystal display module is used, for example, if the dot pitch is 2 mm, the size of a screen of 640 × 400 dots can be reduced to about 1.3 m × 0.8 m.

[0028]

According to the liquid crystal display device of the present invention, the non-display area at the peripheral portion of the liquid crystal display module due to the sealing portion can be reduced, and a large display screen can be constructed by arranging a plurality of liquid crystal display modules. The dot pitch is small and a uniform pitch is obtained. As a result, even when the scroll display is performed, a display without a sense of incongruity can be performed, and the aperture ratio can be increased, so that a high-quality display can be performed.

Further, since the thin light guide plates provided with the holes for light guide are formed one on top of the other, they can be manufactured easily and inexpensively, and the shape and size of the holes can be arbitrarily selected. The cross-sectional shape of the hole provided in each thin plate can be formed in a tapered shape that spreads toward the front side. As a result, the step-like unevenness in the light guide is reduced, so that light scattering in the light guide can be prevented, and the aperture ratio can be further improved.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of a main part of an embodiment of a liquid crystal display device of the present invention.

FIG. 2 is a schematic plan view showing an example in which a plurality of liquid crystal display modules of FIG. 1 are arranged.

FIG. 3 is an enlarged view of a portion A in FIG. 2;

FIG. 4 is an explanatory sectional view of a main part showing an example of a conventional liquid crystal display module.

FIG. 5 is a schematic perspective view showing a part of an example of a liquid crystal display device formed by arranging a plurality of liquid crystal display modules.

FIG. 6 is a partially enlarged plan view of FIG. 5;

[Explanation of symbols]

 1a, 1b Transparent substrate 3 Light guide mask 4 Backlight 5 Liquid crystal display module 6 Antireflection film 7 Pixel (dot) 8 Light guide 9 Light shield 10 Hole

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02F 1/1335 G02B 6/00 301

Claims (1)

(57) [Claims] 1. A transparent substrate on which a transparent electrode that can be driven for each pixel is formed, a seal portion for holding and bonding the two transparent substrates at a constant gap, and the two transparent substrates. A liquid crystal display device comprising: a liquid crystal material filled in a gap of; a polarizing plate disposed outside each of the two transparent substrates; and a backlight disposed on a side opposite to a display surface of the transparent substrate. A liquid crystal display comprising a plurality of light guide plates having holes for guiding light of each pixel on a display surface side of the transparent substrate, the holes being connected to each other to form a light guide portion. apparatus.