JPH07104285A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To increase availability of the original plate of a polarizing plate, to improve quality and to decrease the cost by dividing the one polarizing plate into two or more parts to be provided on the outer surface of a transparent substrate. CONSTITUTION:Two transparent substrates 21, 22, for example, comprising glass are provided with electrode films 23, 24 comprising ITO or SnO2, respectively, and with an oriented film 26 such as polyimide. These transparent substrates 21, 22 are held at specified distance with a spacer and sealed with a sealing agent layer 27. The space between the subsrates is filled with a liquid crystal material to form a liquid crystal layer 28. On both outer faces of the transparent substrate 21, 22 are provided with divided polarizing plates 1, 2, 3 and 4, 5, 6, respectively. Thus, the liquid crystal display panel 10 is produced. The polarizing plates 1, 2, 3 and 4, 5, 6 are adhered to transparent substrates 21, 22 in such a manner that these plates are separated to correspond to the interval of picture elements or the interval of groups of picture elements.

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 device.
More specifically, the present invention relates to a liquid crystal display device in which a polarizing plate is divided and the use efficiency of the polarizing plate material is improved.

[0002]

2. Description of the Related Art A liquid crystal display device consumes less power and costs less than a display device using a light emitting diode or the like, can display clearly even in the daytime, and can have a wide viewing angle with recent technological improvement. As a result, it has come to be used for large indoor and outdoor display devices.

For example, as shown in FIG. 4, a liquid crystal display device includes two transparent substrates 21 and 22 made of glass or the like, electrode films 23 and 24 made of ITO film or SnO ₂ film, and an alignment film made of polyimide. 25 and 26 are provided, and a sealant layer 27 is provided with a spacer (not shown) maintaining a constant gap.
Both transparent substrates 21 and 22 are adhered to each other by filling a gap between them with a liquid crystal material to form a liquid crystal layer 28. Polarizing plates 29 and 30 are provided on both sides of the two transparent substrates 21 and 22, respectively. A liquid crystal display panel is configured. For example, a backlight 31 is provided on the back side of the display surface of this liquid crystal display panel,
Further, a circuit board (not shown) on which a drive circuit is formed is provided.

In this liquid crystal display device, the change in the orientation of the molecules of the liquid crystal caused by the voltage applied to both electrode films 23 and 24 and the light transmittance of the backlight 25 disposed on the back surface side by the polarizing plate are Characters and figures that are changed and assembled with pixels are displayed.

The polarizing plates 29 and 30 used here are obtained by sandwiching a polarizing film generally called an H film between supporting films such as cellulose acetate. A typical manufacturing method of the H film is polyvinyl alcohol (PVA). (3) is stretched while being heated, and is immersed in a solution called H ink containing a large amount of iodine.

[0006]

With the recent increase in the size of liquid crystal display devices, it is necessary to increase the size of polarizing plates used therein. The larger the size of the required polarizing plate,
The size of the end material produced from one original sheet of the polarizing plate (the long original material before being cut into a predetermined size, the same applies hereinafter) also becomes large, and the utilization rate of the original sheet becomes poor. Moreover, the polarizing plate is usually cut from a roll having a width of about 1 m, but the absorption axis direction of the polarizing plate is a long direction, and the absorption axis direction in the liquid crystal display panel is relative to the vertical and horizontal directions of the liquid crystal display panel.
Since it is used in the direction of 45 °, it must be cut diagonally, which further reduces the utilization rate. Further, there is a problem that a partial defect is likely to occur in the polarizing plate, and if a defect occurs even in one large polarizing plate, the entire polarizing plate becomes defective and the cost increases. That is, the size of the display panel of a large-sized liquid crystal display device is about 30 cm × 30 cm, and a polarizing plate of about the same size is required. %.

The present invention has been made to solve the above problems. By dividing a polarizing plate, a plurality of small polarizing plates are combined to increase the utilization rate of the material and improve the quality. An object of the present invention is to provide a liquid crystal display device that can reduce costs.

[0008]

In a liquid crystal display device of the present invention, a liquid crystal material is sandwiched between two transparent substrates each having an electrode film formed thereon, and a polarizing plate is provided outside each of the two transparent substrates. A liquid crystal display device having the above liquid crystal display panel, wherein at least one polarizing plate provided on the outer side of the transparent substrate is divided into two or more.

Further, since a screen is provided on the display surface side of the liquid crystal display panel and an image is displayed on the screen, it is possible to prevent a phantom image due to a break in the polarizing plate even when the screen is viewed obliquely. preferable.

Further, it is preferable that a light-shielding film is provided on the transparent substrate so that light does not pass through the gap between the two or more polarizing plates, because a phantom image due to a break in the polarizing plate can be prevented.

[0011]

In the liquid crystal display device of the present invention, since the polarizing plate is divided, the end material coming out of the raw material is also small, and the ratio of defects due to defects (the area of the defective polarizing plate to the area of the raw material) is small. Therefore, the utilization rate of the original fabric becomes high.

At this time, since the place where the polarizing plate is divided is provided in the gap between the pixels, the display of each pixel is not hindered. Further, a screen is provided on the entire surface of the display screen, and / or a gap between the divided polarizing plates or at least a portion of the transparent substrate corresponding to the gap is provided so that light does not pass through the gap between the combined polarizing plates. By providing the light-shielding film in the gap between the electrodes, light leaking from the gap between the polarizing plates can be blocked even when the display screen is viewed in an oblique direction, and the display quality can be improved.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the liquid crystal display device of the present invention will be described in detail with reference to the drawings. 1 is a sectional explanatory view showing an embodiment of a liquid crystal display device of the present invention, and FIGS. 2 and 3 are sectional explanatory views showing another embodiment of the liquid crystal display device of the present invention. 1 to 3, the same parts as those of the liquid crystal display device shown in FIG. 4 are designated by the same reference numerals.

In FIG. 1, two transparent substrates 21 and 22 made of, for example, glass are provided on an ITO film and a SnO ₂ film, respectively.
Electrode films 23, 24 made of films and the like and an alignment film 26 made of polyimide, etc. are provided, both transparent substrates 21, 22 are held at a constant gap by a spacer (not shown), and the periphery thereof is adhered by a sealant layer 27. A liquid crystal material is filled in the gap to form a liquid crystal layer 28. Polarizing plates 1, 2, 3 and 4, 5, 6 are provided on both sides of the two transparent substrates 21, 22, respectively.
Are separately provided to configure the liquid crystal display panel 10. In this embodiment, the backlight 30 is arranged on the back side of the display screen, and the image is displayed by controlling the transmitted light from the back side. The liquid crystal display panel 10 has a size of 30 cm × 30 cm and a size of 16 × for a large display device on the street, for example.
A device in which 16 or 24 × 24 pixels are formed is used, and in this case, the size of one pixel is 1 cm or more on one side.

The respective dividing positions of the polarizing plates 1, 2, 3 and 4, 5, 6 are attached to the transparent substrate so as to correspond to the pixel gap for each pixel or the gap of a set of a plurality of pixels. A light-shielding film 11 made of resin, nickel plating, or the like is formed in a gap between the electrode films 31 corresponding to the gaps between the polarizing plates 1, 2, and 3 by a method such as printing or plating.
Similarly, the light-shielding film 13 is also formed in the gaps of the electrode films 24 corresponding to the gaps of the polarization plates 4, 5, and 6 so that light does not leak from the gaps of the polarization plates.

In this case, as shown in FIG. 1, when the gap between the polarizing plates 1, 2 and 3 does not match the gap between the electrode films 23, the electrode film which does not correspond to the gap between the polarizing plates 1, 2 and 3 is formed. A light shielding film may be provided also in the gap portion of 23. If the light-shielding film is provided in the gap between the electrode films, the size of the polarizing plate is not so limited, and the size can be adjusted to an integral multiple of the size of the pixel.

The light-shielding films 11, 12, 13, and 14 are polarizing plates 1, 2, and
It is provided to block light leaking from the gaps 3, 4, 5, and 6, and is provided on the side opposite to the liquid crystal layer 28 side of the transparent substrates 21 and 22, that is, on the polarizing plates 1, 2, 3 ... Alternatively, it may be provided on a screen provided on the front side of the display screen.

FIG. 2 shows another embodiment of the liquid crystal display device of the present invention, in which the light shielding film is not on the liquid crystal layer 28 side of the transparent substrates 21 and 22, but on the polarizing plates 1, 2, 3, 4, 5, and 6. This is an example provided on the side, and the light shielding films 15, 16, 17, and 18 are the polarizing plates 1, 2, 3,
It is formed in a gap of 4, 5, and 6. Further, in the present embodiment, the light from the backlight 31 that is transmitted through the liquid crystal layer 28 is displayed on the screen 40.

Light-shielding films 15, 16 formed in the gaps between the polarizing plates
17 and 18 are provided by screen printing or the like as described above. In this embodiment, the light-shielding film is provided in the gap between the polarizing plates on both sides of the liquid crystal display panel. However, the light-shielding films 15 and 16 are formed only in the gap between the polarizing plates 1, 2 and 3 on the display surface side, and the light-shielding film 17, 18 may be omitted.

The screen 40 is made of a film of polycarbonate or acrylic plate having a thickness of about 0.1 to 0.2 mm, and is arranged with a gap of about several mm from the polarizing plates 1, 2, 3 or directly. It is placed in close contact with the polarizing plate. In this way, by irradiating the screen 40 with the transmitted light of the liquid crystal layer 28 and displaying an image on the screen 40, even when the liquid crystal display panel is viewed from the front oblique direction,
The phenomenon that the light which does not pass through the polarizing plate is visually recognized from the break of the polarizing plate and the display quality is deteriorated does not occur, and the users of the liquid crystal display device receive the polarizing plates 1, 2 and 3 and the light shielding films 15 and 16.
You can get a beautiful display without seeing irregularities such as seams.
It is more preferable that the screen 40 is provided so that light from the liquid crystal display panel 10 is projected via the light guide plate 8 so as to narrow the pixel gap, as shown in FIG. The method of displaying on these screens can be similarly applied to the embodiment shown in FIG.

In each of the above-described embodiments, the transmissive type in which the backlight is arranged on the back surface side of the liquid crystal display panel has been described, but light is emitted from the display surface and the reflection plate is provided on the back surface side of the liquid crystal display panel. Even in the reflective liquid crystal display device, the utilization ratio of the polarizing plate is improved by dividing the polarizing plate. However, in the case of the reflection type, it is preferable to use one back side. Further, in the case of a transmission type, the utilization factor can be improved even if only one of the polarizing plates is divided.

In the so-called positive type display in which the background color is white and the display color is dark, only the dark display portion is displayed so that the light of the backlight is selectively opaque. It is not necessary to provide a light-shielding portion at least on the side opposite to the display surface, unless an unnatural display occurs even if light leaks from the gap.

Divided polarizing plates 1, 2, 3, 4, 5, 6
As described above, the size can be arbitrarily set to a size corresponding to one pixel or a plurality of pixels, but it is several cm square or several c depending on the workability of sticking the polarizing plate and the utilization rate of the polarizing plate.
It is preferable to use a strip having a width of m. However, the size of each piece is not limited. From the viewpoint of workability of sticking a polarizing plate, it is preferable to divide the polarizing plate into strips.

[0024]

In the liquid crystal display device of the present invention, since the polarizing plate is divided, it is possible to use a polarizing plate smaller than the size of the liquid crystal display panel. Therefore, the scrap material can be minimized even when the size of the liquid crystal display panel is increased, and the defective portion due to the partial defect can be efficiently removed, so that the effective utilization rate of the raw material is increased and the cost is reduced. You can go down.

Further, by providing a light-shielding film in the gap of the combined polarizing plates or the gap of the corresponding electrode films, it is possible to block the light leaking from the gap of the polarizing plates, so that the light leakage caused by the division of the polarizing plates may occur. It is possible to obtain a high-quality and low-cost liquid crystal display device that can prevent deterioration of display quality.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing an embodiment of a liquid crystal display device of the present invention.

FIG. 2 is a cross-sectional explanatory view showing another embodiment of the liquid crystal display device of the present invention.

FIG. 3 is a sectional explanatory view showing still another embodiment of the liquid crystal display device of the present invention.

FIG. 4 is a cross-sectional explanatory view of a conventional liquid crystal display device.

[Explanation of symbols]

 1, 2, 3, 4, 5, 6 Polarizing plate 10 Liquid crystal display panel 11, 12, 13, 14 Light-shielding film 15, 16, 17, 18 Light-shielding film 21, 22 Transparent substrate 23, 24 Electrode film 31 Backlight 40 Screen

Claims (3)

[Claims] 1. A liquid crystal display device having a liquid crystal display panel in which a liquid crystal material is sandwiched between two transparent substrates each having an electrode film formed thereon, and a polarizing plate is provided outside each of the two transparent substrates. A liquid crystal display device in which at least one polarizing plate provided outside the transparent substrate is divided into two or more. 2. The liquid crystal display device according to claim 1, wherein a screen is provided on the display surface side of the liquid crystal display panel, and an image is displayed on the screen. 3. The liquid crystal display device according to claim 1, wherein the transparent substrate is provided with a light-shielding film so that light does not pass through a gap between the polarizing plates divided into two or more.