JPH08190089A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: To provide a large-screen liquid crystal display device excellent in display quality by making the dead space of the joint of a liquid crystal display panel inconspicuous in the case of constituting a large screen by arranging several liquid crystal display panels. CONSTITUTION: The large-screen liquid crystal display device is constituted by arranging the liquid crystal display panels 1 consisting of two insulating transparent base plates 11 and 12 respectively equipped with an electrode forming a picture element, a liquid crystal layer inserted and held between the base plates 11 and 12, and a polarizing plate provided on the outer surface of the base plates 11 and 12 in an array state or in a matrix state, and providing a light source 2 on one surface side of the panel 1. A transparent light diffusing plate 3 where a spherical concave lens 3a is formed for every picture element of the panel 1 is provided on the surface of the panel 1 on an opposite side to the light source 2.

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 that enables a large-screen display used for displaying destinations at stations.

[0002]

2. Description of the Related Art A liquid crystal display device has lower power consumption and lower cost than a display board using LEDs. Further, with the recent improvement in technology, a wide viewing angle can be achieved, and it is used for outdoor display such as destination display at stations. It is being considered for use as a display board.

In a liquid crystal display device, as shown in FIG. 4, transparent substrates 31 and 32 made of, for example, glass are provided with electrode films 33 and 34 made of an ITO film or a SnO ₂ film, respectively, and an alignment film 35 made of polyimide or the like. 36, both transparent substrates 31 and 32 are adhered to each other with a sealant 37 in a fixed gap, and the liquid crystal material is filled in the gap to form a liquid crystal layer 38.
Is formed, and the polarizing plates 39 and 40 are provided on both sides of the two transparent substrates 31 and 32, respectively, so that the liquid crystal display panel 1 is formed. Further, on the back surface side, a backlight such as a small fluorescent lamp or an electric lamp is formed. Light source 2 consisting of
Is arranged.

By applying a voltage between the electrode films 33 and 34, the light transmittance of the liquid crystal layer is changed to perform display. For example, when the light source is a white light source, by selectively transmitting and blocking light from the light source for each pixel, white characters (normally) are displayed on the dark background color where the light is blocked on the liquid crystal display panel. Black) or vice versa can be displayed.

This liquid crystal display device is, for example, 40 cm ×
When forming with a large screen of 40 cm or more, if it is attempted to form one set of transparent substrates, it is difficult to handle in the manufacturing process, the flatness of the substrate cannot be obtained, and the number of pixels increases and wiring is increased. With the increase in the number of thin film transistors for switching and the like, the entire device becomes defective due to the defect of 1 to 2 elements, so that the yield is extremely reduced, and the liquid crystal display panel 1 having a size of 10 cm square to 20 cm square.
There has been an attempt to form a large screen by arranging the pixels in an array or a matrix.

In this case, the peripheral portion of the liquid crystal display panel 1 has a portion adhered by the sealing agent 37 as described above, and that portion is at least 1.0 mm from the viewpoint of adhesive strength.
The above is necessary, and at the joint of the two liquid crystal display panels 1, a dead space having a width of 2 to 3 mm or more that does not contribute to the display is formed by 37 parts of both sealing agents. Therefore, as shown in FIG. 5, a diffusion sheet (projection sheet) 43 is provided apart from the surface of the liquid crystal display panel 1 on the display surface side by about several mm so that the dead space of the joint is not noticeable. Incidentally, reference numeral 44 in FIG. 5 denotes a diffusion plate for making the light of the light source 2 uniform.

[0007]

However, when the above-mentioned diffusing sheet is placed on the front surface of the liquid crystal display panel, the diffusing sheet is composed of the light diffusing layer and the base material, and attenuates when light is transmitted. Therefore, in order to improve the visibility of the display image by the light transmitted through the diffusion sheet, the brightness of the light source, which is the backlight, must be increased, and there is a problem that the power consumption increases. Further, unless the diffusion sheet is arranged at a distance of several mm from the surface of the liquid crystal display panel, the effect of making the dead space between the liquid crystal display panels inconspicuous due to the spread of light cannot be exhibited, and the thickness of the liquid crystal display device becomes thick. There is a problem.

On the other hand, in Japanese Unexamined Patent Publication No. 5-281536, in order to make a pixel frame which is a pixel interval of a color liquid crystal display panel inconspicuous, a concave lens or the like is formed on a substrate on a display surface side of a glass substrate which constitutes the liquid crystal display panel. A configuration is disclosed in which a beam expanding optical system is embedded and a beam width converging optical system such as a convex lens is embedded in a substrate on the backlight side. Specifically, a method of changing a refractive index of a portion corresponding to each pixel electrode of a glass substrate is disclosed. It is disclosed. However, in this method, the lens constituent material must be embedded in advance in the portion corresponding to the pixel electrode of the glass substrate, misalignment is likely to occur after assembly, and the light transmitted through the pixel is immediately incident on the lens portion, Since there is no lens portion on the pixel interval which is the pixel frame, the pixel frame cannot be completely erased. In particular, there is a problem that it cannot be used for the purpose of covering the joint portion of the liquid crystal display panels when a number of liquid crystal display panels are arranged.

The present invention solves such a problem, and when a large screen is formed by arranging a plurality of liquid crystal display panels, the dead space of the joints of the liquid crystal display panels is made inconspicuous, and the large screen liquid crystal of excellent display quality is obtained. An object is to provide a display device.

[0010]

A liquid crystal display device of the present invention comprises two insulating transparent substrates each provided with an electrode forming a pixel, and a liquid crystal layer sandwiched between the two insulating transparent substrates. A large-screen liquid crystal display device in which liquid crystal display panels each composed of a polarizing plate provided on the outer surface of the two insulating transparent substrates are arranged in an array or a matrix, and a light source is provided on one surface side thereof. A transparent light diffusing plate in which a spherical concave lens is formed for each pixel of the liquid crystal display panel is provided on the surface of the liquid crystal display panel opposite to the light source.

Since the spherical portion of the spherical concave lens is formed so as to cover at least the entire surface of the pixel, the lens portion is formed up to the non-display area of the pixel interval, and between the pixels and between the display panels. It is preferable because the dead space can be made inconspicuous.

It is preferable that the light source side surface of the liquid crystal display panel is provided with a light condensing plate in which a convex lens is formed for each pixel because the amount of light taken into each pixel increases and the brightness is improved.

The liquid crystal display panel is formed so that the pixel interval between the adjacent liquid crystal display panels and the pixel interval in the liquid crystal display panel are equal, and the lenses are arranged uniformly. Since it is only necessary to provide a transparent substrate, it is easy to manufacture, and since the pixel intervals are all uniform on a large display screen, an image with excellent display quality can be obtained, which is preferable.

[0014]

According to the present invention, since the transparent light diffusing plate in which the spherical concave lens is formed for each pixel is provided on the surface of the liquid crystal display panel on the display surface side, the light transmitted obliquely through the pixel portion is provided. Is further spread in an oblique direction while advancing through the insulating transparent substrate of the liquid crystal display panel, and then is incident on the concave lens portion. Therefore, the light that has passed through the pixels can be sufficiently diffused on the dead space between the pixels. Moreover, since the transparent light diffusing plate in which the concave lens is similarly formed is also provided on the joint of the display panel, the joint of the display panel can be displayed as inconspicuous as the interval of each pixel.

Since the light source side of the liquid crystal display panel is provided with a light condensing plate having a convex lens formed for each pixel, light is condensed at each pixel portion, and light transmitted through the liquid crystal layer of each pixel is inclined. Since it is easy to emit the light, the light easily proceeds to the gaps between the pixels, and the non-display portion becomes inconspicuous.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the liquid crystal display device of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic sectional view showing an embodiment of the liquid crystal display device of the present invention, and FIG. 2 is an enlarged view showing one pixel portion thereof.
FIG. 3 is a diagram illustrating an example of the positional relationship between pixels and a spherical concave lens.

In FIG. 1, reference numeral 1 denotes a liquid crystal display panel, which has the same structure as the conventional structure described with reference to FIG. 4, but is shown in a simplified manner and includes two insulating transparent substrates 11 and 12 and FIG.
Only the pixel portion 13 constituted by the pixel electrode 34 and the seal portion 14 which is the sealant 37 in FIG. 4 are shown. The surface of the liquid crystal display panel 1 opposite to the light source 2 is characterized by a transparent light diffusing plate 3 having a spherical concave lens 3a formed for each pixel as shown in FIG.

In this embodiment, a light collecting plate 4 having a convex lens 4a formed for each pixel is provided on the light source 2 side of the liquid crystal display panel 1.

Further, the pixel portion 13 sandwiching the space A between the pixel portions 13 of the liquid crystal display panel 1 and the joint 1a of the liquid crystal display panel 1.
Are formed so as to be equal to the distance B. When forming a liquid crystal display panel, the seal portion 14 is usually wider than the pixel spacing A in the liquid crystal display panel 1 because it requires a sticking portion with a sealant and a cut portion such as a glass substrate. However, even if the seal portion is formed as narrow as possible and the normal pixel interval A is widened, the liquid crystal display panel 1
Since the liquid crystal display panel 1 is formed so that the pixel spacing A in the interior and the spacing B between the pixels sandwiching the joint 1a are equal, the lenses 3a and 4a are evenly spaced on the light diffusing plate 3 and the light collecting plate 4. It is preferable because it can be provided and the light diffusion plate 3 and the light condensing plate 4 can be easily attached to the liquid crystal display panel 1.
Further, since the pixel pitch is provided at a constant interval regardless of the joint, the display image is not partially extended and the display characteristics are excellent.

The operation of the light diffusing plate having the concave lens 3a and the light collecting plate 4 having the convex lens 4a according to the present invention is shown in FIG.
Will be described with reference to.

The light 5 emitted from the light source 2 is condensed by the convex lens 4a so as to be collected in the central portion of the pixel portion 13 of the liquid crystal display panel 1. Actually, the convex lens 4a is not perfectly focused, and the incident light is not parallel rays and is incident from all directions of the surroundings. It acts to bend the optical path to the part. When the pixel portion 13 is in the light passing state, the light bent in the pixel portion 13 passes through the pixel portion 13 as it is, and even in the insulating transparent substrate 11, goes straight in an oblique direction, and the concave lens 3a of the light diffusion plate 3 is used.
To reach. The light traveling straight by the concave lens 3a is further refracted outward and travels to the observer side. Therefore, the visibility is improved even when the large-sized liquid crystal display device is viewed obliquely.

The concave lens 3a may have a structure as shown in FIGS. 1 and 2 as long as it has a thin top and a large thickness on the end side, or may have an ordinary concave lens shape. In the present invention, since the light diffusion plate 3 provided with the concave lens 3a is provided on the surface of the liquid crystal display panel 1, the concave lens 3a is provided.
The edges of a can be formed so as to overlap with each other in the gap portion of the pixel portion 13. As described above, the light obliquely incident is emitted from the non-display area between the pixels via the concave lens 3a. , The non-display area between pixels becomes inconspicuous.

Since each pixel portion 13 is formed in a square shape and the concave lens 3a is formed in a spherical shape, the spherical concave lens 3 is formed.
If a is formed so as not to overlap, the diagonal direction of the pixel portion 13 is not covered by the concave lens 3a, and the range of the gap of the pixel portion 13 covered by the concave lens 3a is narrowed. Therefore, as shown in FIG. 3, it is preferable that the spherical portion is formed so as to cover at least the entire surface of the pixel portion 13 including the diagonal line portion.

The light diffusing plate 3 and the light collecting plate 4 can be manufactured by molding a transparent material such as glass or plastics, and even a large size of about 40 cm × 40 cm can be manufactured by one sheet, or 10 cm. You may arrange and arrange thing of about * 10 cm on the surface of the liquid crystal display panel 1.

In the embodiment shown in FIGS. 1 and 2 described above, the light collecting plate 4 for collecting the light from the light source 2 is provided.
By providing the above, it is possible to effectively collect the light from the light source 2 and improve the brightness, and since the light is advanced obliquely through the pixel portion 13, it is easy to send the light to the end portion of the concave lens 3a, which is preferable. Since scattered light enters from all directions and travels in an oblique direction even without the light collecting plate 4, by providing the light diffusing plate 3 having the concave lens 3a, the gap between the pixel portions 13 and the joint portion 1a of the liquid crystal display panel 1 are provided. The non-display area can be made inconspicuous, and a liquid crystal display device having a large display screen with excellent display quality can be obtained.

[0027]

As described above, according to the present invention, since the light transmitted through the pixel portion seems to be emitted from the gap between the pixel portions, the liquid crystal display panels are arranged in an array or a matrix. Even if there is a non-display area at the periphery of the liquid crystal display panel, it can be made inconspicuous. As a result, there is no discontinuity of pixels due to the seams between pixels or display panels, and a large-screen liquid crystal display device with excellent display quality can be obtained.Destination displays at stations and airports, street display boards, and large-screen TVs. It can be used for screens.

Further, according to the present invention, since a diffusing sheet that attenuates light is not used, it is not necessary to improve the brightness of the light source as a backlight, and excellent display can be obtained with low power consumption.

Further, since it is only necessary to provide a transparent light diffusing plate with a lens provided for each pixel on the surface of the arranged liquid crystal display panel, it is possible to easily manufacture the device, the cost is not increased, and the diffusing is performed. Since it is not necessary to dispose the sheet apart from the surface of the liquid crystal display panel like a sheet, the size can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an embodiment of a liquid crystal display device of the present invention.

FIG. 2 is an enlarged explanatory diagram of one pixel portion in FIG.

FIG. 3 is a diagram illustrating a relationship between a pixel portion and a lens portion.

FIG. 4 is an explanatory diagram of a liquid crystal display panel.

FIG. 5 is an explanatory diagram of an example of a large-screen liquid crystal display device in which conventional liquid crystal display panels are arranged.

[Explanation of symbols]

 1 liquid crystal display panel 2 light source 3 light diffusing plate 3a concave lens 4 light collecting plate 4a convex lens

Claims (4)

[Claims] 1. Two insulating transparent substrates each provided with an electrode for forming a pixel, a liquid crystal layer sandwiched between the two insulating transparent substrates, and an outer surface of the two insulating transparent substrates. A liquid crystal display device having a large screen, in which a liquid crystal display panel including the polarizing plate is arranged in an array or a matrix, and a light source is provided on one surface side thereof.
A liquid crystal display device comprising a transparent light diffusion plate having a spherical concave lens formed for each pixel of the liquid crystal display panel on the surface of the liquid crystal display panel opposite to the light source. 2. The liquid crystal display device according to claim 1, wherein the spherical concave portion of the spherical concave lens is formed so as to cover at least the entire surface of the pixel. 3. The liquid crystal display device according to claim 1, wherein a light condensing plate having a convex lens formed for each pixel is provided on the surface of the liquid crystal display panel on the light source side. 4. The liquid crystal display panel according to claim 1, wherein the liquid crystal display panel is formed so that a pixel interval sandwiching a joint between the adjacent liquid crystal display panels is equal to a pixel interval in the liquid crystal display panel. Liquid crystal display device.