JP3312114B2 - 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, and more particularly to a large liquid crystal display.

[0002]

2. Description of the Related Art In recent years, display devices for televisions, monitors, and OA equipment have been increasing in size.

[0003] Among these display devices, liquid crystal display devices are more suitable for weight reduction, lower power consumption, and higher definition than other display devices, and are widely used in notebook personal computers and the like. . In addition, there is a strong demand for a larger liquid crystal display device as a wall-mounted television or a large monitor. However, when the size of the screen of the liquid crystal display device is increased, a defective rate due to disconnection of a signal line, a pixel defect or the like in a manufacturing process rapidly increases.
In addition, there are many problems such as warpage or deflection of a large substrate generated during the manufacturing process and the necessity of increasing the size of the manufacturing apparatus in accordance with the substrate size. For these reasons, it is difficult to mass-produce a large-sized liquid crystal display device, and a large-sized liquid crystal display device becomes very expensive.

In order to solve this problem, a plurality of small liquid crystal display elements are connected to each other to increase the size of a screen as a large multi-display type liquid crystal display device. Specifically, the following scheme has been proposed.

First, the configuration of the liquid crystal display device disclosed in JP-A-5-107535 and JP-A-7-128652 is shown in FIG. In the liquid crystal display device 100, two liquid crystal display devices 101 and 102 are arranged on the same plane at a predetermined interval, and backlight devices 103 and 104 are provided on the back surface of each liquid crystal display device, and a field expansion plate 10 is provided on the front surface.
5 are provided. The field-of-view expanding plate 105 is a transparent resin thin plate 105a made of acrylic resin, polycarbonate, or the like.
Or a plurality of optical fiber bundles 105a
Are bundled, and the tip on the image display surface 105b side is inclined so as to be in close contact with each other. Two liquid crystal display elements 101, 1
02 are arranged at predetermined intervals, the liquid crystal display elements 101, 1
02 and the non-display areas 101a and 102a of the liquid crystal display elements 101 and 102 can be made invisible. However, in this method, since the field-of-view expanding plate 105 is used, the thickness and weight of the display device are larger than those of the direct-view type. Further, when an optical fiber is used for the visual field enlarging plate 105, it becomes very expensive.

Next, FIG. 6 shows a configuration of a liquid crystal display device disclosed in Japanese Patent Laid-Open Nos. 5-188340 and 5-341310. This liquid crystal display device 110
Irradiates the liquid crystal display elements 111 and 112 with light from the backlights 113 and 114, and
Light that has passed through 11 and 112 is enlarged by optical systems 115 and 116.
Is projected on the screen 117 via the. Magnifying optical system 1
15 and 116, the image of the first liquid crystal display element 111 and the image of the second liquid crystal display element 112 are joined on the screen 117. As a result, a large rear-projection-type liquid crystal display device 110 with no noticeable seams is realized. In this method, since an image is projected on the rear surface of the screen, it is necessary to use a screen having scattering or semi-transmission, and the contrast is reduced. In addition, power consumption increases due to a decrease in light use efficiency in the magnifying optical system and an increase in backlight luminance. Further, there is a problem that the thickness and weight of the display device are increased as compared with the direct-view type.

As a method for solving these problems, Japanese Patent Application Laid-Open No. 8-122770 and Japanese Patent Application Laid-Open No.
FIG. 7 shows a configuration of a multi-display type liquid crystal display device disclosed in Japanese Patent Application Laid-Open No. 5-105, in which the joints of the liquid crystal display elements are made inconspicuous.

The liquid crystal display device 120 includes a liquid crystal bonding panel 123 in which two liquid crystal display elements 121 and 122 are arranged on the same plane of a large-sized substrate 124 and fixed by a refractive index adjusting material 125, and a liquid crystal bonding panel 123 on the back surface. A backlight 126 made of a cathode tube or the like, and polarizing plates 127 and 12 having polarizing axes orthogonal to the front and back surfaces of the liquid crystal bonding panel 123.
8.

The refractive index adjusting material 125 is used for the liquid crystal display element 12.
If the glass substrates 129 and 130 have the same spectral transmittance as the glass substrates 129 and 130 and have the same refractive index in the entire visible light region, the joint at the joint 131 cannot be identified. Therefore, the refractive index adjusting material 125 used for joining the two liquid crystal display elements 121 and 122 and the large substrate 124 includes:
The glass substrate 12 of the liquid crystal display elements 121 and 122 at the time of curing
UV-curable resin adjusted so as to have the same refractive index as 9, 130 is used.

[0010] Thus, it is possible to obtain a natural image in which joints are inconspicuous.

[0011]

However, it is very difficult to find the refractive index adjusting material 125 that satisfies the above-mentioned perfect conditions, and the problem that the joint at the joint 131 is slightly noticeable remains. It cannot be completely solved.

The ultraviolet curable resin used as the refractive index adjusting material 125 is adjusted so as to have the same refractive index as the glass substrates 129 and 130 after curing. Refractive index adjusting material 125
For example, the distribution of shrinkage during curing occurs due to uneven thickness. When a distribution occurs in the amount of shrinkage, an internal stress occurs, and a distribution occurs in the refractive index. Therefore, light is refracted and scattered at the junction 131 between the liquid crystal display elements 121 and 122.

Further, the refractive indices of the glass substrates 129 and 130 and the refractive index adjusting material 125 change depending on the wavelength dispersion and the temperature, and the amount of change in the refractive index of the refractive index adjusting material 125 is the refractive index of the glass substrates 129 and 130. It is much larger than the amount of change. For example, when the temperature changes by 50 ° C., the refractive index adjusting material 125
Is 50 times or more the change in the refractive index of the glass substrates 129 and 130. Therefore, at a certain temperature,
Even if the refractive indices of the refractive index adjusting material 125 and the glass substrates 129 and 130 are made to match with each other so that joints cannot be identified, when the temperature changes, the refractive indices of the glass substrates 129 and 130 and the refractive index adjusting material 125 do not match. Will come
The seam becomes conspicuous at the joint 131.

In the liquid crystal display device disclosed in JP-A-8-76075, a spacer is mixed in a refractive index adjusting material. This spacer is used to keep the distance between the reinforcing plate and the liquid crystal display element constant, and the diameter thereof is equal to the distance between the reinforcing plate and the liquid crystal display element, and is much larger than the wavelength of light. Light refraction / scattering occurs at the interface between different materials, and the effect is greater as the diameter of the spacer is larger. In addition, since the interface between the spacer and the refractive index adjusting material is spherical, light is further scattered.

For the above reasons, the liquid crystal display element 1
There is a problem that a joint is conspicuous at the joint portion 131 between the first and second joints 21 and 122.

SUMMARY OF THE INVENTION In view of these problems, an object of the present invention is to provide a large-sized liquid crystal display device which consumes less power, has excellent display quality, and has less noticeable joints between liquid crystal display elements.

[0017]

In order to achieve the above object, a backlight device and a liquid crystal display device according to the present invention have the following configurations.

The liquid crystal display device according to claim 1 is arranged a plurality of liquid crystal display device as the display surface on the same plane is flush Rutotomoni, bonding between adjacent said liquid crystal display element member
A liquid crystal display device comprising: a composite liquid crystal display element filled with and bonded to the liquid crystal display element, and a backlight device that illuminates the composite liquid crystal display element from the back.
The refractive index of the liquid crystal display element when the refractive index is cured as the bonding material
Using a material that is almost equal to the refractive index of the glass substrate,
The bonding material has a refractive index of the glass substrate of the liquid crystal display element.
Glass powder having almost the same folding ratio is mixed .

A liquid crystal display device according to a second aspect is the liquid crystal display device according to the first aspect, wherein spherical glass beads are used as the glass powder.

A liquid crystal display device according to a third aspect is the liquid crystal display device according to the second aspect, wherein the glass beads are formed to have a diameter of 0.4 μm or less.

According to a fourth aspect of the present invention, in the liquid crystal display device according to any one of the first to third aspects, the refractive index of the glass powder is the refractive index of the glass substrate of the liquid crystal display element. And up to the third decimal place.

A liquid crystal display device according to a fifth aspect is the liquid crystal display device according to any one of the first to fourth aspects, wherein the glass powder is made of the same material as the substrate of the liquid crystal display element. is there.

A liquid crystal display device according to a sixth aspect of the present invention is the liquid crystal display device according to any one of the first to fifth aspects, wherein the bonding material, the glass powder, and the glass substrate of the liquid crystal display element are provided. Refractive index of at least two persons is 3rd decimal point
It is equal to the order.

The operation of the present invention will be described below.

According to the first aspect of the present invention, since the glass powder is mixed in the bonding material, the influence of the change in the refractive index is reduced even if the bonding material contracts and hardens during curing. It is possible to reduce the conspicuous joint at the joint between the liquid crystal display elements.

According to the second aspect of the present invention, by using glass beads as the glass powder, it is possible to reduce the influence of the change in the refractive index of the bonding material, and to make the joints between the liquid crystal display elements stand out. Can be reduced.

According to the third aspect of the present invention, by setting the diameter of the glass beads to 0.4 μm or less, the influence on light passing through the glass beads can be reduced. The joints can be made inconspicuous.

According to the fourth aspect of the present invention, by making the refractive index of the glass powder equal to the refractive index of the substrate of the liquid crystal display element to the third decimal place, the junction width between the liquid crystal display elements can be reduced. However, the effect of the joining material is reduced, and the joint of the joining portion between the liquid crystal display elements can be made inconspicuous.

According to the fifth aspect of the invention, the glass powder is made of the same material as the substrate of the liquid crystal display element, so that the bonding width between the liquid crystal display elements is reduced, and the influence of the bonding material is reduced. As a result, the joint at the junction between the liquid crystal display elements can be made less noticeable.

According to the sixth aspect of the present invention, the refractive index of at least two of the bonding material, the glass powder, and the glass substrate of the liquid crystal display element is matched to the third decimal place, so that each interface has The refraction and scattering of the light can be eliminated, and the joint at the junction between the liquid crystal display elements can be made inconspicuous.

[0031]

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

An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a sectional view of the liquid crystal display device of the present invention.

The liquid crystal bonding panel 1 has a configuration in which the image display surfaces of the liquid crystal display elements 2 and 3 are bonded to each other so as to be flush, and a reinforcing plate 4 is attached to the flush surfaces. I have. Polarizing plates 5 and 6 whose polarization axes are orthogonal to each other are provided on the front and back surfaces of the liquid crystal bonding panel 1, and a backlight device 7 is provided on the back surface side.

The bonding between the liquid crystal display elements 2 and 3 and the reinforcing plate 4
Is attached by the bonding material 8 and the bonding material 8
Is mixed with glass beads 9.

The liquid crystal display elements 2 and 3 have a structure in which the liquid crystal 13 is sealed with two glass substrates 10 and 11 and a sealing material 12. Then, by applying a voltage based on an image signal between transparent electrodes (not shown) provided on the glass substrates 10 and 11, the transmittance of the liquid crystal display elements 2 and 3 is controlled. Is adjusted, and an image is displayed on the surfaces of the liquid crystal display elements 2 and 3.

On the glass substrate 10, a black matrix 13 and a color filter (not shown) are formed.
At this time, the gap b between the connected liquid crystal display elements 2 and 3
Is the black matrix 1 required per pixel
3 is smaller than the line width a. If the gap b between the joined liquid crystal display elements 2 and 3 is smaller than the line width a of the black matrix 13, the pixel pitch of the entire display screen is not disturbed at the junction between the liquid crystal display elements 2 and 3. Does not give a sense of discomfort.

In order to perform such bonding, a sealing material 12 for bonding the two glass substrates 10 and 11 is precisely arranged in the vicinity of the connection portion between the liquid crystal display elements 2 and 3 and very close to the pixel. Need to be. Therefore, an acrylic or epoxy-based ultraviolet curable resin is used as the sealant 12, and is arranged with high accuracy in the vicinity of the pixel. One side of the liquid crystal display elements 2 and 3 obtained as described above is cut by dicing or the like at the dividing line at the edge of the pixel display area.

Further, the influence of a change in the refractive index of the joining material can be reduced as the joining width of the joining portion becomes smaller. Therefore, it is necessary to make the joining width as narrow as possible in order to make the joints inconspicuous. In order to reduce the gap “b” between the joined liquid crystal display elements 2 and 3, it is necessary to reduce the unevenness of the joint end faces of the liquid crystal display elements 2 and 3. Therefore, the joining portions of the liquid crystal display elements 2 and 3 are cut by dicing or the like, and the end surfaces of the joining portions are ground while maintaining straightness to reduce the irregularities on the end surface surfaces and then joined. As a result of preparing a simple sample and examining the bonding width, when the bonding is performed so that the gap b between the liquid crystal display elements 2 and 3 is 50 μm or less, the joint is inconspicuous.

The bonding material 8 is an ultraviolet-curable resin such as an acrylic or ene / thiol-based resin.
Use a material that has the same refractive index as Glass beads 9 are mixed with the bonding material 8. The use of the ultraviolet curable resin as the bonding material 8 facilitates the mixing of the glass beads 9 and the handling during curing. The glass beads 9 have the same refractive index as the glass substrates 10 and 11 up to the third decimal place, or are made of the same material and composition as the glass substrates 10 and 11, or are made of the glass substrates 10 and 11. Either one of them has exactly the same spectral transmittance and refractive index as those of the glass substrates 10 and 11. It is more preferable to use glass beads 9 having a particle diameter of 400 nm or less, which is smaller than the wavelength of visible light of 400 nm to 700 nm.

By placing the glass beads 9 in the bonding material 8, the proportion of the bonding material 8 in the volume of the bonding portion 15 can be reduced. This has the same effect as reducing the amount of the bonding material 8 and reducing the distance b between the liquid crystal display elements 2 and 3, and the amount of contraction of the bonding material 8 at the bonding portion 15 and the refractive material due to the temperature of the bonding portion 15. 8 can be kept small.

Thus, a large-sized liquid crystal display device in which the joint between the liquid crystal display elements 2 and 3 is inconspicuous can be realized.

As described above, the diameter of the glass beads 9 is 4
It is preferable to use one having a thickness of 00 nm or less. The production of the glass beads 9 having such a size is performed by a gas phase growth method or a collision pulverization method.

In the gas phase growth method, glass beads 9 having a uniform particle size and a small particle size can be produced by growing particles in a gas phase of a glass component. According to this,
By using manufactured small diameter glass beads,
The joints between the liquid crystal display elements can be made less noticeable. Further, glass beads having a small diameter can be mass-produced.

The collision pulverization method is a method in which a certain substance is beaten at a high speed to a fixed member to give an impact force to reduce the size. By melting the fine powder of the glass substrates 10 and 11 crushed by this method in a hot fluid, the glass substrates 10 and 11 are melted.
Thus, glass beads 9 having the same spectral transmittance and refractive index as those of 11 and having a small particle diameter can be obtained. According to this, by using glass beads having a small diameter manufactured by the collision pulverization method, it is possible to reduce conspicuous joints between the liquid crystal display elements. Further, glass beads having a small diameter can be mass-produced.

FIG. 2 shows the relationship between the refractive index and the reflection loss. This is a result of calculating light loss due to reflection at the interface between the glass substrates 10 and 11 and the bonding material 8 at the bonding portion 15. The refractive index of the glass substrates 10 and 11 is represented by n, the refractive index of the bonding material 8 is represented by the horizontal axis, and the reflection loss of light is represented by the vertical axis. The reflection loss of light becomes convex downward to a minimum when the refractive index of the bonding material is n. When a simple sample was prepared and the appearance of the joint was confirmed, the joint could hardly be recognized if the refractive indices of the glass substrates 10 and 11 and the bonding material 8 were equal to the third decimal place.

FIGS. 3 and 4 show an example in which a large panel is formed by joining a plurality of liquid crystal display elements.

First, as shown in FIG. 3, four 10-inch liquid crystal display elements 16, 17, 18, and 19 are arranged on the same plane, and a liquid crystal display device is obtained by the above-described method. The control signal to each liquid crystal display element is applied to the terminals 20 and
21. Then, by controlling each liquid crystal display element at the same time, an image is displayed on the display unit. Thus 10
2 inconspicuous joints using inch LCD display elements
A large-sized 0-inch liquid crystal display device can be realized.

Next, similarly, as shown in FIG. 4, two 15-inch liquid crystal display elements 23 and 24 are arranged on the same plane, and the liquid crystal display device is formed by the above-described method, whereby the joints are made inconspicuous. A large liquid crystal display device of inches can be realized.

By using a plurality of small liquid crystal display elements in the manner described above, a large liquid crystal display device with no noticeable joint can be realized.

[0050]

As described above, according to the present invention, in a large liquid crystal display device of a multi-display system in which a plurality of small liquid crystal display elements are connected, a problem that a joint is conspicuous at a joint portion of the liquid crystal display elements. Thus, a low-cost large-sized liquid crystal display device can be realized.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a configuration of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between a refractive index and a reflection loss.

FIG. 3 is a layout diagram of a liquid crystal display element according to a second embodiment of the present invention.

FIG. 4 is a layout diagram of a liquid crystal display element according to a third embodiment of the present invention.

FIG. 5 is a diagram illustrating a conventional liquid crystal display element.

FIG. 6 is a diagram illustrating another conventional liquid crystal display element.

FIG. 7 is a diagram illustrating still another conventional liquid crystal display element.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 liquid crystal bonding panel 2 first liquid crystal display element 3 second liquid crystal display element 4 reinforcing plate 5, 6 polarizing plate 7 backlight device 8 bonding material 9 glass beads 10, 11 glass substrate 12 sealing material 13 liquid crystal layer 14 black matrix DESCRIPTION OF SYMBOLS 15 Joining part 16 1st liquid crystal display element 17 2nd liquid crystal display element 18 3rd liquid crystal display element 19 4th liquid crystal display element 20, 21 Terminal part 22 Display part 23 1st liquid crystal display element 24 2nd Liquid crystal display elements 25, 26 Terminal 27 Display

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-217491 (JP, A) JP-A-8-76074 (JP, A) JP-A-8-1222769 (JP, A) JP-A-9-97 22016 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G02F 1/1347 G02F 1/1333 G02F 1/13 505 G09F 9/30

Claims (6)

(57) [Claims] 1. A are arranged a plurality of liquid crystal display device as the display surface on the same plane is flush Rutotomoni, adjacent liquid
The liquid crystal display element is filled with a bonding material between the liquid crystal display elements.
A combined liquid crystal display element, and a backlight device that illuminates the composite liquid crystal display element from the back, in a liquid crystal display device, wherein the refractive index of the liquid crystal display element when the refractive index is cured as the bonding material
Using a material that is almost equal to the refractive index of the glass substrate,
The bonding material has a refractive index of the glass substrate of the liquid crystal display element.
A liquid crystal display device comprising glass powder substantially equal to the folding ratio . 2. The liquid crystal display device according to claim 1, wherein spherical glass beads are used as the glass powder. 3. The liquid crystal display device according to claim 2, wherein the glass beads have a diameter of 0.4 μm or less. 4. The liquid crystal display device according to claim 1, wherein a refractive index of the glass powder is equal to a refractive index of a glass substrate of the liquid crystal display element to three decimal places. Characteristic liquid crystal display device. 5. The liquid crystal display device according to claim 1, wherein the glass powder is made of the same material as a substrate of the liquid crystal display element. 6. The liquid crystal display device according to claim 1, wherein a refractive index of at least two of the bonding material, the glass powder, and the glass substrate of the liquid crystal display element is a decimal point. A liquid crystal display device characterized by being equal to third place.