JPH0675233A - Liquid crystal display element and its production - Google Patents

Abstract

PURPOSE:To make the cell thickness of a liq. crystal display element constant without using a spacer. CONSTITUTION:The thickness of the central part of the liq. crystal layer 6 injected between two substrates 2 and 3 is measured. The distance between the central parts of the substrates 2 and 3 is mechanically adjusted based on the measured result by the suction of cell suction pumps 135a and 135b or the compression of cell pressing compressors 136a and 136b. Consequently, the liq. cell 122a is injected from an injection port 7 or discharged, and the thickness of the central part of the liq. crystal layer is made constant.

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 having a liquid crystal layer sandwiched between two substrates and a method for manufacturing the same.

[0002]

2. Description of the Related Art In the above-mentioned liquid crystal display device, a space between two substrates arranged opposite to each other is partially sealed with a sealing material, and liquid crystal is injected into the inside through an injection port which is a part thereof. Done by. Conventionally, the injection is performed by a liquid crystal injection device having a liquid crystal tank inside a chamber whose internal atmospheric pressure is adjustable. For example, the interior of the room is 10 ^-3 t with a vacuum pump
After vacuuming to the vicinity of orr, the inlet of the liquid crystal display element is placed in the liquid crystal tank with the inlet facing down, and the inlet is immersed in the liquid crystal. Liquid crystal is injected between the two substrates thus formed, and finally an ultraviolet curing resin is applied to the injection port by a dispenser or the like, and the resin is irradiated with ultraviolet rays to seal the injection port.

By the way, the liquid crystal is injected into a plurality of liquid crystal display elements simultaneously, and the injection port is sealed when the liquid crystal is injected into all the liquid crystal display elements. Therefore, in the conventional case, the injection port is sealed after all the plurality of liquid crystal display elements are filled with the liquid crystal. On the other hand, the optimum liquid crystal injection time differs for each liquid crystal display element over all of the plurality of liquid crystal display elements. As a result, the gap between the two substrates of the liquid crystal display element (hereinafter referred to as the cell thickness) becomes thicker as the actual liquid crystal injection time is longer than the optimum liquid crystal injection time, and the gap between the liquid crystal display elements is increased. There was a problem that the cell thickness varied.

When the cell thickness varies in this way, the hues displayed by the liquid crystal display element having a thick cell thickness and the liquid crystal display element having a thin cell thickness also vary, and the response speed of the liquid crystal changes. Differences and variations in the threshold value of the driving voltage for switching between the display state and the non-display state of the liquid crystal occur, which causes deterioration in display quality. In order to make the cell thickness constant between the liquid crystal display elements, there is a method of interposing a spacer such as plastic beads or glass fiber between the two substrates. In the case of this method, the vicinity of the spacer is present. However, there is a problem in that the alignment of the liquid crystal is disturbed, and thereby the display quality is degraded.

FIG. 42 is a plan view showing an example of another conventional liquid crystal display element, and FIG. 43 is a sectional plane line G in FIG.
It is sectional drawing seen from -G. Conventional liquid crystal display element 61
Is a transparent first substrate 62 and a second substrate 62 such as glass.
A liquid crystal is enclosed between the substrates 63 by a sealing material 64 to form a liquid crystal phase 66. In the liquid crystal layer 66 and the sealing material 64, a spacer 65 formed of resin or glass in a spherical or cylindrical shape is mixed. When the spacer 65 and the substrates 62 and 63 are in close contact with each other, the first substrate 62
The gap between the second substrate 63 and the second substrate 63, that is, the film thickness of the liquid crystal layer 66 is set.

The liquid crystal layer 6 of the first substrate 62 and the second substrate 63
An electrode for applying a voltage to the liquid crystal for each picture element of the display image and an alignment film for determining the alignment of the liquid crystal molecules are formed on the surface on the 6 side by performing a simple matrix operation or an active matrix operation. Therefore, a color filter layer and a light shielding layer are formed as needed. In the case of active matrix operation, the switching element that controls the voltage applied to the pixel electrode is amorphous Si or polycrystalline S.
It is composed of a TFT (thin film transistor) made of i or the like and is formed on the surface of one substrate.

A conventional method of manufacturing the liquid crystal display element 61 will be described below. First, an electrode or an alignment film is prepared in advance on the first substrate 62 and the second substrate 63, and a sealing material 6 such as a thermosetting resin or a photocurable resin is provided around the surface of the first substrate 62.
4 is applied by a screen printing method while leaving the opening 67, and then a spacer is applied to 100 to 5 per 1 mm ^2.
Spraying is performed using a wet spraying method or a dry spraying method so that the distribution density is 0.

Next, the second substrate 63 and the first substrate 62 are aligned and fixed to each other, and then the sealing material 64 is cured by heating or irradiation of ultraviolet rays to assemble the liquid crystal cell.

Next, in order to inject liquid crystal into the obtained liquid crystal cell, the air in the liquid crystal cell is evacuated, and then the opening 6 is formed.
Liquid crystal is injected from 7 and the opening 67 is filled with another sealing material 68.
A liquid crystal display device is obtained by sealing with.
After that, if necessary, a step of shaping the substrate, a step of dividing the substrate, a step of attaching a polarizing plate or a light reflecting plate, and the like are performed.

However, the conventional liquid crystal display element 61
Because the spacer 65 exists in the liquid crystal layer 66,
It has the following problems. (1) When the spacers 65 are scattered on the surface of the substrate 62, the spacers 65 tend to aggregate in units of several to several tens, and therefore, the film thickness of the liquid crystal layer becomes uneven, and The light transmittance is reduced, resulting in display failure. (2) The orientation of liquid crystal molecules in the vicinity of the spacer 65 becomes non-uniform, and the light modulation efficiency at that portion is reduced, or light leakage occurs due to the transmission of light by the spacer 64 itself, resulting in display failure and reduction in contrast. .
(3) When the liquid crystal is injected into the liquid crystal cell, the film thickness of the liquid crystal layer is adjusted by adjusting the injection time. Therefore, if liquid crystal injection processing is performed on a plurality of liquid crystal cells at the same time, Due to the influence of assembling error and processing accuracy error, the thickness of the liquid crystal layer varies for each liquid crystal display element, resulting in poor contrast. Such a problem becomes remarkable especially when a display image is enlarged in a projection device using a liquid crystal display element.

FIG. 44 shows another prior art manufacturing method in the bonding step. First, a sealing material 64 made of a thermosetting resin mixed with a spacer 65 for controlling a gap between the substrates is applied on one substrate 63 by a screen printing method along a sealing pattern, and the other substrate 62 is applied. Spacers 65 for controlling the gap are also scattered on the entire surface. At this time, the amount of spacers 65 to be dispersed is 10
It is about 0 to 150 pieces / mm ² . Next, the pair of substrates 62 and 63 are attached to each other. By the pressing device including the upper surface plate 67 having the cushioning material 68 mounted thereon and the lower surface plate 69,
The pressure was applied by the pressing load 70 so that the pressure was evenly applied to the entire surfaces of the substrates 62 and 63. The substrates 62 and 63 are heated while being held by the pressing device to cure the sealing material 64. Therefore, the gap between the substrates 62 and 63 is controlled by the spacer 65 mixed in the sealing material 64 and the spacers 65 scattered on the entire surface of the substrate 62.

In the above-mentioned conventional method, in order to realize a liquid crystal display device having a uniform gap, it is essential to disperse the spacers 65. It is necessary to apply a large load 70 to crush the sealing material 64 up to a predetermined gap of the spacer 65 mixed in the sealing material 64. This load 70
In order to support the substrate and maintain a uniform gap between the substrates 62 and 63, it is necessary to sprinkle a large amount of spacers 65.
Such a large amount of spacers 65 causes the following new problems. (1) Since a large amount of spacers 65 are present in the display area for displaying an image, the aperture ratio is lowered, and thereby the display quality and the contrast are lowered. (2) Luminous spots are generated by light leakage due to aggregation of several to several tens of spacers 65,
The display quality is degraded. (3) Pixel defects occur due to destruction of switching elements such as thin film transistors when the substrates 62 and 63 are pressed.

Further, in the case of the conventional manufacturing method in which the spacers 65 are not scattered, since the medium for gap control does not exist in the display portion, the pressing operation causes the substrates 62 and 63 of the display portion to be concave or convex. It tends to have a shape, and a uniform gap cannot be realized. As a result, the display quality is degraded. Further, in the case where the size of the display element is large, for example, one side exceeds 25 mm, it is difficult to form the cell gap uniformly.

In the prior art, the size of the spacerless liquid crystal display element is mainly about 1 inch, and in particular, the injection of liquid crystal in the spacerless liquid crystal display element exceeding 1 inch is performed by vacuum injection. According to the law, the following problems occur.

(1) When the liquid crystal is injected by the vacuum injection method as in the prior art, the inside of the chamber containing the pair of substrates is evacuated to immerse the liquid crystal display element in the liquid crystal tank. After that, if the pressure in the chamber is returned to atmospheric pressure all at once, the two substrates will bend due to the pressure difference between the inside and outside of the liquid crystal display element, and if the deflection becomes larger than the cell gap, the pair of substrates will come into contact with each other. Resulting in. By contacting the upper and lower substrates in this manner, the following problems further occur.

(1a) It causes damage to elements such as switching elements formed on the TFT substrate, or damages the alignment films formed on the surfaces of both substrates, resulting in poor alignment of liquid crystal molecules. .

(1b) It becomes difficult for liquid crystal to enter between both substrates, and it takes a lot of time until it is completely injected between both substrates. Therefore, there is a problem that the manufacturing process requires a long time. Further, when both substrates are finally in contact with each other, liquid crystal injection failure occurs.

(2) Since the size of the spacerless liquid crystal display element is mainly around 1 inch, the deflection of both substrates due to the pressure difference is very small, which is not a problem, but the size exceeding 1 inch. In the liquid crystal display device, the above problems may occur depending on the physical properties (thickness and Young's modulus) of the glass substrate used.

The present invention has been made to solve such a conventional problem.

A first object of the present invention is to provide a liquid crystal display device and a method for manufacturing the same which can realize a high quality image display due to the absence of spacers in the liquid crystal layer.

A second object of the present invention is to prevent the occurrence of irregularities in the central portion of the display substrate without interposing a spacer in the display portion and prevent the occurrence of display defects.
It is an object of the present invention to provide a liquid crystal display device capable of enlarging the display area, increasing the aperture ratio, and realizing high-contrast display.

A third object of the present invention is to provide a method of manufacturing a liquid crystal display device which can make a gap between a pair of substrates of the liquid crystal display device constant without using a spacer.

[0023]

The liquid crystal display device of the present invention is a liquid crystal display device in which a liquid crystal layer is sandwiched between a first substrate and a second substrate. Are fixed with a sealant that does not contain spacers,
In addition, the gap D between the first substrate and the second substrate and the film thickness d of the sealing material satisfy the condition of d <D, whereby the above object is achieved.

In the present invention, the gap D and the film thickness d of the sealing material may satisfy the condition of D ≦ 1.2 × d.

The method of manufacturing a liquid crystal display device according to the present invention is the first
A sealing material mixed with a spacer that sets a gap between the substrate and the second substrate is interposed between the first substrate and the second substrate,
A step of placing an elastic sheet having a cutout end portion on the back surface of one of the first substrate and the second substrate and pressurizing it in a region where the sealing material is arranged; and curing the sealing material. The method includes the steps of injecting liquid crystal into the space formed by the first substrate, the second substrate, and the sealing material, thereby achieving the above object.

In the present invention, both sides of the elastic sheet have a height of 5 to 30 μm and a cycle of 200 to 800 μm.
Unevenness may be formed.

The method of manufacturing a liquid crystal display device according to the present invention comprises a step of providing a sealing material on the peripheral portions of two substrates which are arranged opposite to each other except a part thereof, and a required injection into the liquid crystal injection port which is a part thereof. A step of setting a larger amount of liquid crystal than the amount of liquid crystal, a step of injecting the set liquid crystal between two substrates due to a pressure difference between the inside and the outside of the two substrates, and an injection between the two substrates. The step of measuring the thickness of the central portion of the liquid crystal layer, and the distance between the two substrates at the central portion are mechanically adjusted based on the measurement result of the thickness, and the liquid crystal is injected from the injection port. The method includes the steps of injecting or discharging and the step of sealing the injection port, whereby the above object can be achieved.

In the present invention, the mechanical adjustment of the separation distance may be performed by a mechanism for separating or approaching both substrates while holding both of the two substrates.

The method for producing a liquid crystal display element of the present invention is a method for producing a liquid crystal display element in which a pair of substrates are fixed to each other by a sealing material and liquid crystal is held between the pair of substrates. A step of applying a sealing material mixed with a spacer for controlling a gap between the pair of substrates on one of the pair of substrates, and a gap control for a display portion defined on the pair of substrates. A step of bonding the one substrate and the other substrate of the pair of substrates in a state where the gap between the pair of substrates is held only by the sealing material without interposing a spacer, and curing the sealing material. And a step of cutting the pair of substrates so that at least one display cell is formed, and a step of injecting liquid crystal into the gap, thereby achieving the above object. Rukoto can.

In the present invention, at least one of the pair of substrates has an electrode corresponding to its display area, and the electrode may include a transparent electrode.

In the present invention, one of the pair of substrates may have a means for controlling the electro-optical effect of liquid crystal.

The method for producing a liquid crystal display element of the present invention is a method for producing a liquid crystal display element in which a pair of substrates are fixed to each other by a sealant and liquid crystal is held between the pair of substrates. A step of applying a sealing material mixed with a spacer that determines the gap between the pair of substrates on one of the pair of substrates, and a gap near the center of the display portion defined by the pair of substrates. A step of combining the one substrate and the other substrate of the pair of substrates in a state where the gap between the pair of substrates is held only by the sealing material without interposing a spacer for control, At least one side of the display area is selected to be 25 mm or more, whereby the above object can be achieved.

In the present invention, at least one of the pair of substrates may have a transparent electrode.

In the present invention, at least one of the pair of substrates may have a means for controlling the electro-optical effect of liquid crystal.

According to the method of manufacturing a liquid crystal display element of the present invention, a pair of substrates are fixed to each other by a sealing material mixed with a spacer that determines a gap between the pair of substrates, and a display near the center of the gap between the substrates is displayed. In a manufacturing method for manufacturing a liquid crystal display device in which liquid crystal is held between a pair of substrates in which a spacer is not arranged in a region, a composite buffer material containing a plurality of pressure media and buffer media is used. , A step of pressing the entire surface of one of the pair of substrates, and a step of curing the sealing material and adhering them to each other while the pair of substrates is being pressed. The above object can be achieved.

In the present invention, the buffer medium is a medium which is isotropic in the transmission of pressure, and is an elastic body including mutually independent cells of either gas or liquid, or alkali halide crystal grains, Alternatively, it may be a substance selected from solid pressure media such as pyroferrite.

In the present invention, of the above composite cushioning materials,
At least one of the plurality of pressure media is a pressurizing material having a smoothness equal to or higher than that of the pair of substrates bonded together and having a flexural strength higher than that of the pair of substrates bonded together. Therefore, the pair of substrates may be arranged so that the smooth surfaces of the pressure medium and the pair of substrates are in contact with each other.

In the present invention, a slit may be formed on at least one surface of the pressure member to prevent air from being trapped.

In the present invention, after the sealing material is cured,
It may include a step of heating to a temperature not lower than the glass transition temperature of the sealing material.

In the present invention, the sealing material used for bonding the pair of substrates includes a UV curing agent which contains a polymerization reaction initiator activated by ultraviolet rays and which activates an unreacted reaction by heat. It may be a thermosetting combined resin composition.

According to the method of manufacturing a liquid crystal display element of the present invention, a pair of substrates are fixed to each other by a sealing material containing a spacer that determines a gap between the pair of substrates, and a display near the center of the gap between the substrates is displayed. In a manufacturing method for manufacturing a liquid crystal display device in which a liquid crystal is held between a pair of substrates in which a spacer is not arranged in a region, at least one substrate of the pair of substrates is provided with a gap defined by the spacer. And a step of applying a sealing material to one of the pair of substrates, and a step of curing the sealing material. The purpose can be achieved.

In the present invention, at least one of the pair of substrates may have a transparent electrode.

In the present invention, one of the pair of substrates may have a means for controlling the electro-optical effect of the liquid crystal.

In the present invention, the substrate may be pressed so that the cell gap is determined while maintaining the viscosity of the sealing material constant.

In the present invention, the substrate may be pressed so as to define the cell gap by controlling the viscosity of the sealing material and the pressing force on the sealing material.

In the present invention, the viscosity and the pressing stress of the sealing material may be determined based on the viscosity dependence of the stress-strain characteristic of the sealing material.

In the present invention, the sealing material is a photocurable resin composition containing a photopolymerization initiator that is activated by light, or in the resin composition, reaction of unreacted components is caused by heat. It may be a photocurable and thermosetting combined resin composition that is activated.

According to the method of manufacturing a liquid crystal display element of the present invention, the first substrate and the second substrate which are arranged so as to face each other and define a display region are provided.
A step of providing a sealing material in which a spacer for determining a mutual distance between the first substrate and the second substrate is provided on a peripheral edge portion of the display region excluding the liquid crystal injection port on at least one of the substrates; A step of applying a vacuum to the inside and the periphery of the first substrate and the second substrate, a step of attaching a liquid crystal to the liquid crystal injection port, and an atmospheric pressure around the first substrate and the second substrate, And a step of increasing the pressure at an atmospheric pressure change rate in a range in which the second substrate and the second substrate are kept apart from each other, thereby achieving the above object.

In the present invention, the atmospheric pressure change rate is 1
It may be cmHg / min or less.

In the present invention, liquid crystal injection may be stopped when the gap between the first substrate and the second substrate is the distance defined by the spacer.

In the present invention, a transistor array made of amorphous silicon may be formed on the first substrate.

In the present invention, the first substrate may have a transistor array made of polycrystalline silicon.

In the present invention, the second substrate may have a color filter layer.

In the present invention, the second substrate may have a light shielding layer.

[0055]

According to the present invention, since the spacer for setting the gap between the first substrate and the second substrate is present only in the sealing material, the spacer is not present in the liquid crystal layer, and It is possible to eliminate the display failure and the contrast failure due to it, and the thickness D of the liquid crystal layer and the thickness d of the sealing material satisfy the condition of d <D.
The elastic restoring force of the substrate and the second substrate and the internal pressure of the liquid crystal layer are balanced to reduce the thickness variation of the liquid crystal layer.

Further, when the thickness D of the liquid crystal layer and the thickness d of the sealing material satisfy the condition of D ≦ 1.2 × d, a uniform liquid crystal layer can be realized.

Further, according to the method of manufacturing a liquid crystal display element of the present invention, an elastic sheet having a region 2 where a sealing material is present and a cut-out end portion is placed on the back surface of one of the substrates and pressed, By curing the sealing material, it becomes possible to manufacture a liquid crystal display element in which the thickness D of the liquid crystal layer is greater than the thickness d of the sealing material, particularly a liquid crystal display element having a condition of D ≦ 1.2d. Even if a spacer is not present in the liquid crystal layer, a liquid crystal display element having a uniform thickness of the liquid crystal layer and a small error can be easily obtained.

As described above, according to the present invention, a liquid crystal display element having a uniform liquid crystal layer thickness and a small manufacturing error even if a spacer does not exist in the liquid crystal layer through which modulated light passes. Therefore, it is possible to eliminate display defects and contrast defects due to the presence of spacers, and it is possible to realize extremely high-quality image display especially when used in a projection device or the like that performs enlarged image display. .

Further, on both sides of the elastic sheet, the height is 5 μm.
Since the unevenness of ˜30 μm and the cycle of 200 μm to 800 μm is formed, the pressure acting on the substrate is made uniform,
The adhesion of the spacer mixed in the sealing material and each substrate becomes uniform over the entire surface of the substrate, and the thickness error of the sealing material can be reduced.

In the present invention, the thickness of the central portion of the liquid crystal layer injected between the two substrates is measured, and the distance between the central portions of the two substrates is mechanically determined based on the measurement result. adjust. As a result, the liquid crystal is injected or discharged from the injection port, and the thickness of the central portion of the easy push becomes a constant value.

In the case of the present invention, as described in detail, the liquid crystal is injected while the cell thickness is controlled and the injection port is sealed, so that the cell thickness can be made uniform and a constant value. It is possible to provide a liquid crystal display element which can significantly improve the yield, has no display unevenness, and has high contrast and good display quality.

It is possible to prepare a liquid crystal display element having no spacers in the liquid crystal layer of the liquid crystal display element or having a significantly reduced amount of spacers dispersed. Further, according to the manufacturing method of the present invention, it is particularly difficult to manufacture because it is easily bent, and even in a liquid crystal display element having no display region spacer and a large display region size, a uniform cell is obtained. A gap can be realized.

In the manufacturing method of the present invention, a so-called multi-chamfering manufacturing method of forming a plurality of electrode groups corresponding to a display on a substrate and bonding them at the same time, which has been difficult in the past, can be carried out. A liquid crystal display device having a uniform cell gap among the spacers in the display region can be manufactured.

T for controlling the electro-optical effect of the liquid crystal
An active element such as FT (thin film transistor) or a first insulating transparent substrate on which a transparent electrode is formed, and a second insulating transparent substrate on which a black mask pattern composed of a color filter layer or a light shielding film is formed. At the time of bonding, a thermosetting resin is used as the sealing material in the conventional method for manufacturing a liquid crystal display element.However, in the present invention, the viscosity of the sealing material is reduced in the curing step of the sealing material. UV curable resin is used, which is hardly accompanied.

The ultraviolet curable resin is screen-printed onto the second insulating transparent substrate to seal the main body of the seal portion, the temporary fixing, and the printability of the sealing material, and to the first and second insulating transparent substrates. A sealing material is applied in a dummy pattern for the purpose of preventing the biasing of the pressing pressure applied to the sealing material in the pressing step, and the first and second insulating transparent substrates are formed on the picture element portions above these. They are positioned relative to each other and bonded to each other, and only the temporary fixing pattern is irradiated with ultraviolet rays so that the two substrates are not displaced, and the patterns are cured.

The cell gap determining factors in the subsequent pressing step for controlling the cell gap are the viscosity of the sealing material and the pressing pressure applied to the sealing material, which are determined based on the pressure-cell gap characteristics of the sealing material. Under a constant viscosity condition, the pressure σ and the cell gap d are expressed by the following first formula.

[0067]

Equation 1 can be approximated by σ = Fd ² . The symbols F and n in the first equation are values unique to the sealing material used.

From the relationship of the first expression, the present invention is based on the fact that by selecting an appropriate resin material, the variation of the cell gap d can be made small with respect to the fluctuation of the pressure σ, and can be made a constant value. The viscosity of the sealing material and the pressing load when setting the target cell gap are determined according to the first equation, which is performed by controlling the temperature of the entire substrate to control the viscosity of the sealing material. Press with the pressing load of. The pressing state is maintained until the sealing material is sufficiently pressed to the target cell gap, and when the cell gap reaches the target value, UV irradiation is applied to cure the sealing material while maintaining the pressing state. I do. The pressing is maintained until the curing reaction of the sealing material is completed.

Thereafter, the substrate is heated at a temperature equal to or higher than the glass transition temperature of the cured sealing material. Thereby, the strain of the glass generated in the pressing step can be relaxed, and a more uniform cell gap can be realized.

When the sealing material is a combination resin of photo-curing and thermo-setting, the heating step is carried out at the same time.

Next, the substrate is cut into the shape of a liquid crystal display element, and liquid crystal is injected by a vacuum injection method. At this time, when the liquid crystal cannot be sufficiently injected into the liquid crystal display element, the substrate surface of the liquid crystal layer of the liquid crystal display element is physically sucked with the liquid crystal inlet being immersed in the liquid crystal, and By pulling the substrates opposite to each other, the liquid crystal is injected straight into the liquid crystal display element. This step is performed while measuring the cell gap, and when the cell gap becomes uniform, the liquid crystal injection port is coated with an ultraviolet curable resin, and ultraviolet irradiation is performed to cure the resin and seal the injection port.

Through the above steps, a liquid crystal display device having a uniform cell gap can be prepared without using any spacer.

In the pressing step for controlling the cell gap, which is the manufacturing step of the liquid crystal display element, by utilizing the pressure-cell gap characteristic with respect to the viscosity of the ultraviolet curable resin used as the sealing material, the spacer is provided in the sealing material and the liquid crystal layer. It is possible to produce a liquid crystal display device having a uniform cell gap without having any of the above.

As described above, according to the present invention, the spacer for controlling the cell gap is not provided at all,
A liquid crystal display device having a uniform cell gap can be produced. Therefore, it is possible to prevent the problem of reduction in aperture ratio due to the spacer interposed in the liquid crystal layer and the reduction in display quality due to defective alignment of the liquid crystal near the spacer, as in the conventional case.
A liquid crystal display device having high contrast and excellent display quality can be produced. Even in the pressing step of controlling the cell gap, the element or the alignment film is not damaged due to the load concentration on the spacer, or the cell gap unevenness due to the decrease in the uniformity of the stress distribution does not occur. No defect occurs in the active element for controlling the temperature, the wiring material, the alignment film, etc., the manufacturing yield is improved, and the display characteristics can be made uniform. Further, since the spacer is not required, the production process can be greatly simplified and the production cost can be reduced.

Further, a-Si TFT or polycrystalline Si
When the first substrate on which the TFT is formed and the second substrate on which the color filter layer or the black mask pattern is formed are attached to each other, a spacer such as glass fiber is used as a sealing material to hold the liquid crystal layer. After mixing with a resin material and applying it to the second substrate by seal printing, both substrates are bonded to each other without spraying spacers on the first substrate. A thermosetting resin, an ultraviolet curable resin, or the like is used as the resin of the sealing material. After that, a pressing step is performed, and the liquid crystal display element is manufactured through curing and dividing work of the sealing material in an oven.

When liquid crystal is injected into the liquid crystal display element thus manufactured, the first substrate and the second substrate of the liquid crystal display element are balanced with the injected liquid crystal as follows. The liquid crystal is injected until the state is reached.

In the conventional manufacturing method, the liquid crystal display element or the liquid crystal is set, and the air layer in the space of the display area portion surrounded by the sealing material of the liquid crystal display element is evacuated. After vacuum evacuation, after the degassing process of the set liquid crystal is sufficiently done, soak the injection port of the liquid crystal display element in the liquid crystal tank,
When the vacuum outside the liquid crystal display element is brought to atmospheric pressure, the liquid crystal begins to enter the space. At this time, since there is no spacer for maintaining the cell gap in the display region between the first substrate and the second substrate, the cell gap becomes extremely small.

At this time, the atmospheric pressure around the liquid crystal display element is normally returned to the atmospheric pressure. However, as described above, the deflection of each substrate due to the pressure difference between the inside and the outside of the liquid crystal display element is larger than the cell gap. Sometimes both boards are in contact.
As a result, defective liquid crystal injection, damage to the alignment film, and defective liquid crystal alignment occur.

Therefore, in the present invention, the speed or the ultimate pressure at which the vacuum state outside the liquid crystal display element under vacuum is returned to the atmospheric pressure is adjusted so that the inside and the outside of the liquid crystal display element are adjusted. The pressure is controlled so that the pressure difference is kept constant. This prevents both substrates from contacting each other. Thereby, the liquid crystal inside the liquid crystal display element has no bubbles, and it is possible to prevent the two substrates from coming into contact with each other when the liquid crystal is injected between the first substrate and the second substrate.
This is because the deflection amount Δd of both substrates is proportional to the difference (P0−P1) between the internal pressure of the liquid crystal display element and the ambient pressure. That is, it can be expressed as Δd = K (P0−P1).

Finally, the force for recovering the cell gap between the first substrate and the second substrate to the state before the liquid crystal injection and the liquid crystal so that the cell gap between the two substrates becomes small. Although the force of pulling the substrates is in equilibrium, the force of pulling both substrates by the liquid crystal is small and both substrates restore their original shape.

Then, after the liquid crystal is injected into the liquid crystal display element and filled, the liquid crystal adhering to the vicinity of the injection port is wiped off, a UV curable resin is applied to the injection port with a dispenser or the like, and ultraviolet rays are irradiated. Then, the applied resin is cured and the injection port is sealed.

In this way, a spacer is not required for controlling the cell gap, and a liquid crystal display element having a uniform cell gap and high display quality can be manufactured.

According to the present invention, when the liquid crystal is injected into the liquid crystal display element having no spacer in the display region by the vacuum injection method, the inside and outside of the liquid crystal display element are arranged so that the pair of substrates do not contact each other. By controlling so that the pressure difference of 2 does not exceed the restoring force against the deformation of both substrates, a liquid crystal display element with a uniform cell gap and high display quality can be produced in a short time without causing element destruction or alignment failure. Can be created. As a result, a liquid crystal display element having a size exceeding 1 inch can be easily manufactured without using a spacer.

When the liquid crystal of the present invention is injected, the spacer does not exist in the display area by adjusting the ultimate pressure of the internal and external pressures or the external pressure of the liquid crystal display element and the fluctuation speed of the external pressure. When producing a liquid crystal display element, the liquid crystal display element can be produced without causing damage to the alignment film or liquid crystal injection failure, and the liquid crystal injection time can be shortened. Therefore, a liquid crystal display device having high contrast and good display quality can be produced.

[0085]

1 is a plan view showing a liquid crystal display element according to a first embodiment of the present invention, and FIG. 2 is a sectional line A of FIG.
It is sectional drawing seen from -A. Liquid crystal display element 1 of the present embodiment
Includes a liquid crystal layer 6 in which a liquid crystal is sealed by a sealing material 4 between a first substrate 2 and a second substrate 3 having a light-transmitting property such as glass, and a resin or glass is spherical or cylindrical. The spacers 5 formed in the above are present only in the sealing material 4, and the spacers 5 and the substrates 2 and 3 are in close contact with each other, so that the gap between the first substrate 2 and the second substrate 3 That is, the thickness of the liquid crystal layer 6 is set.

On the surfaces of the first substrate 2 and the second substrate 3 on the liquid crystal layer 6 side, electrodes for applying a voltage to the liquid crystal for each pixel of a display image by performing a simple matrix operation or an active matrix operation, An alignment film that determines the alignment of liquid crystal molecules is formed, and a color filter layer and a light shielding layer are formed as necessary. In the case of active matrix operation, the switching element that controls the voltage applied to the pixel electrode is amorphous Si (hereinafter a-Si) or polycrystalline Si.
(Hereinafter, p-Si) and the like, and is formed on the surface of one of the substrates.

FIG. 3 is a cutaway perspective view showing an example of a color liquid crystal display device by an active matrix operation using the liquid crystal display element shown in FIGS. In this example, a plurality of picture element electrodes 10 arranged in a zigzag pattern on the surface of the first substrate 2, a plurality of switching elements 11 for controlling a voltage applied to each picture element electrode 10, and each switching element. A scanning electrode 12 that drives the element 11 and a signal electrode 13 that transmits a display signal to each switching element 11 are formed. On the other hand, on the surface of the second substrate 3, a color filter layer 15 having red (R), green (G), and blue (B) color filters is provided for each pixel electrode 10 for each pixel electrode 10.
And the common electrode 14 is formed on the surface thereof.

The liquid crystal layer 6 is formed between the first substrate 2 and the second substrate 3, and the polarizers 16 and 17 are arranged on the back surfaces of the first substrate 2 and the second substrate 3, respectively. As an example, when light is incident from the back surface side of the first substrate 2, the optical property of the liquid crystal is changed by the voltage applied between the pixel electrode 10 and the common electrode 14, and the back surface of the second substrate 3 is changed. The light emitted to the side is modulated.

Since the spacer 5 is not arranged in the liquid crystal layer 6 of the color liquid crystal display device thus obtained, it is possible to provide a high quality image without display defects.

Next, a method of manufacturing the liquid crystal display element 1 shown in FIG. 1 will be described. First, the first substrate 2 and the second substrate 3 on which electrodes and alignment films are formed in advance are prepared. On the other hand, as the spacer 5, for example, glass fibers having a diameter of 5 μm are dispersed in an ultraviolet curable resin such as an epoxy acrylate resin, and the weight of the glass fibers is 5 g per 1 g of the resin.
The sealing material 4 adjusted to a mixing ratio of 0 mg is prepared.

Next, as shown in the plan view of FIG. 4, the sealing material 4 in which the spacers 5 are dispersed is formed on the surface of the first substrate 2 by using a seal printing method, a screen printing method, or the like, leaving an opening 7. , Line width 0.4mm in the remaining seal area other than the opening 7.
Apply by degree. Hereinafter, an example of assembling six liquid crystal cells on one substrate will be described, but the present invention is not limited to such an example.

Next, as shown in the cross-sectional view of FIG. 5, the first substrate 2 and the second substrate 3 are aligned with each other and bonded to each other, and then a press provided with metallic surface plates 31 and 32. Installed in the device, each surface plate 31, 3 on the surface of the substrate 2, 3
So that the pressure from ² becomes ¹ to 1.5 kg / cm ² .
By applying the pressing force Fa to the entire substrates 2 and 3, the sealing material 4 is crushed so that the spacer 5 mixed in the sealing material 4 and the first substrate 2 and the second substrate 3 come into close contact with each other.

Next, as shown in the partial cross-sectional view of FIG. 6, a fluororesin 33 is applied to a cloth in which glass fibers 33a are plain-woven.
An elastic sheet 33 having a thickness of 0.15 mm impregnated with b is prepared, and as shown in the plan view of FIG.
A cutout process is applied to a shaded region 34 in the drawing so as to substantially match the coating shape of the sealing material 4 interposed between the substrate 3 and the substrate 3. FIG. 8 is a partially enlarged view of FIG. 7, showing the position X of the cut-out end which is the peripheral edge of the shaded area 34, the distance X from the outer edge of the seal material 4 after pressing, and the width of the seal material 4 after pressing. The relation with Y is preferably cut out so as to satisfy the relational expression of Y / 3 ≦ X ≦ Y / 2.

Next, as shown in the sectional view of FIG. 9, the cut-out elastic sheet 33 was placed on the back surface of the second substrate 3 described above, and the alignment as shown in FIG. 8 was performed. After that, it is installed in a press machine configured to have a translucent quartz glass surface plate 35 and a metal surface plate 36, and the pressure applied to the substrates 2 and 3 by the press device is 1
The force Fb is applied to the entire surfaces of the substrates 2 and 3 so as to be less than kg / cm ² . Then, as shown in the partial cross-sectional view of FIG. 10, the pressure is concentrated in the region where the elastic sheet 33 is present, and the gap between the first substrate 2 and the second substrate 3 is formed outside the sealing material 4 of the liquid crystal cell. The second gap is narrowed so that the gap between the first substrate 2 and the second substrate 3 is widened inside the sealing material 4.
The substrate 3 is deformed. In order to make the pressure distribution in the elastic sheet 33 uniform, as shown in FIG. 6, the height Q is 5 μm to 30 μm and the period P is set on both sides of the elastic sheet 33.
It is preferable that unevenness of 200 μm to 800 μm is formed.

While maintaining this deformed state, the surface plate 3
The sealing material 4 is cured by irradiating it with ultraviolet rays UV for a predetermined time from the light source 37 arranged on the back surface side of the sealing material 5, and the gap inside the sealing material 4, that is, the region where the liquid crystal is injected,
A liquid crystal cell larger than the thickness of the sealing material 4 can be obtained. The gap between the first substrate 2 and the second substrate 3 of the liquid crystal cell thus obtained is 5 μm in the spacer 5 part and 5.2 μm ± 0.1 μm in the vicinity of the inside of the seal material 4, Approximately 5.8 μm in the central part of. Next, 6
The substrates 2 and 3 on which two liquid crystal cells are formed are cut into individual liquid crystal cells, and, for example, after 10 sheets are housed in the jig 11 with the directions of the openings 7 aligned, the liquid crystal shown in FIG. It is fixed inside the injection device 40. A vacuum exhaust pump 43 is connected to a vacuum container 47 of the liquid crystal injecting device 40 via a valve 42, and a leak valve 41 for introducing nitrogen gas N ₂ is arranged. The container holding 46 is installed so that it can be vertically aligned by the outer linear moving means 44.

First, the valve 42 is opened and the vacuum exhaust pump 43 is opened.
To drive the vacuum inside the vacuum container 47 to a degree of vacuum of 1 × 10 ^{−4 to} 3
After vacuum evacuation to × 10 ⁻⁴ Torr, the valve 42 is closed and the vacuum evacuation pump 43 is stopped. Next, the container 45
Is moved upward to immerse the opening 7 of the liquid crystal cell in the liquid crystal 46 in the container 45, the leak valve 41 is opened, and the vacuum container 4 is opened.
By introducing nitrogen gas N ₂ into the liquid crystal 7 and returning the pressure to about atmospheric pressure, the liquid crystal 46 is injected into the liquid crystal cell.

Next, the liquid crystal display element 1 shown in FIGS. 1 and 2 can be obtained by taking out from the vacuum container 47 and sealing the opening 7 of the liquid crystal cell with another sealing material 8 such as resin. . Immediately after the liquid crystal is injected, the vacuum container 47
When measuring the thickness of the liquid crystal layer of the liquid crystal cell taken out from
A value of 5.3 μm ± 0.1 μm was obtained. Therefore, the thickness of the liquid crystal layer can be controlled without depending on the liquid crystal injection time by pressing the liquid crystal cell with the cut-out elastic sheet 33 interposed and curing the sealing material 4. Further, the thickness error of the liquid crystal layer of the liquid crystal display element 1 thus obtained is within the range of ± 5%, and the liquid crystal display element 1 with less manufacturing variation can be obtained.

The second embodiment of the present invention will be described below.

FIG. 12 shows a liquid crystal injection device preferably used in the manufacturing method of this embodiment. This apparatus includes a vacuum chamber 102. The inside of the vacuum chamber 102 is evacuated by the vacuum exhaust pump 105, and when the leak valve 103 provided in the pipe 104 is opened, the atmospheric pressure can be achieved by the nitrogen gas flowing through the pipe 104. Vacuum chamber 102
A liquid crystal jig elevating mechanism 110 is provided therein. As shown in FIGS. 13 and 14, the liquid crystal jig elevating mechanism 110 has a jig 111 composed of an upper plate 111a, a lower plate 111b, and a support 111c, and has a height on the inner surface side of the support 111c. Instead, the liquid crystal display element 10 is mounted on the plurality of supporting members 12 provided.
1 can be set, and the entire jig 111 is an elevating mechanism 1 below it.
It is configured to move up and down by 13. Support tool 1
No. 12 has a Teflon (trademark) film formed on its surface, and when the liquid crystal display element 101 is set, the liquid crystal display element 101
I try not to hurt.

Further, in the vacuum chamber 102, a dispenser 120 for supplying liquid crystal to the liquid crystal display element 101 set on the support 112 is provided. The dispenser 120 is a control mechanism 1 for the XYZ axis directions in FIG.
It is supported by 21 and can be moved in the X-axis direction, the Y-axis direction and the Z-axis direction by this control mechanism 12.
In the dispenser 120, the liquid crystal 122 a is stored in the liquid crystal tank 122 that stores the liquid crystal 122 a.
The dispenser 120 applies the liquid crystal 122a to the liquid crystal display element 101 via the control mechanism 121. The liquid crystal tank 122 is provided with a liquid crystal defoaming pump 123.
23, the liquid crystal 122a is defoamed.

In the vicinity of the liquid crystal jig elevating mechanism 110 described above, the moving mechanism 1 which receives the liquid crystal display element 101 from the liquid crystal jig elevating mechanism 110 and passes it to the liquid crystal layer thickness adjusting mechanism 130.
24 are provided. The moving mechanism 124 includes a belt conveyor and has a fixed height. When the liquid crystal display element 101 is moved from the liquid crystal jig elevating mechanism 110 to the moving mechanism 124, the liquid crystal jig elevating mechanism 110 is entirely lowered, and the liquid crystal display element 101 is attached to the belt of the moving mechanism 124.
Upon contact with, the moving mechanism 124 pulls out the liquid crystal display element 101 from the liquid crystal jig elevating mechanism 110 and conveys it to the liquid crystal layer thickness adjusting mechanism 130 side.

The liquid crystal layer thickness adjusting mechanism 130 is provided with two stages 131 and 132 on the upper side and the lower side, respectively.
1 has a fixed height, and the upper stage 132 is configured to be movable up and down by a lifting mechanism 133. The liquid crystal display element 101 conveyed by the moving mechanism 124 is set on the lower stage 131. The liquid crystal display element 101 in the liquid crystal layer thickness adjusting mechanism 130 is shown enlarged. On the upper surface of the stage 131, one end of an optical fiber 137a for measuring cell thickness and a hole 131b for depressurizing and pressurizing are provided. The other end of the optical fiber 137a is connected to a cell thickness measuring device 134a, and a pressure reducing / pressurizing hole 131b is provided.
Is connected to the cell adsorption pump 135a and the cell pressurizing compressor 136a through a passage.

On the other hand, on the lower surface of the stage 132, one end of an optical fiber 137b for measuring cell thickness and a hole 132b for depressurizing and pressurizing are provided. Optical fiber 137
The other end of b is connected to the cell thickness measuring device 134b, and the depressurizing / pressurizing hole 132b is connected to the cell adsorbing pump 135b and the cell pressurizing compressor 136b through a passage. It should be noted that the upper surface of the stage 131 and the lower surface of the stage 132 are respectively provided with O-rings 138a, 1
38b is provided.

A method of manufacturing the liquid crystal display element of this embodiment using the liquid crystal injection device having the above structure will be described.

First, a TFT (thin film transistor) is used as a switching element at a stage where no liquid crystal is injected by a normal liquid crystal display element manufacturing process.
A 3-inch size TFT liquid crystal display element 10 formed in a matrix on either the substrate 101a or 101b.
1 is produced. In this liquid crystal display element 101, as shown in FIG. 15, a TFT substrate 101a on which a TFT (thin film transistor) as a switching element is formed and a counter substrate 101b are arranged so as to face each other, and a sealing material is provided around the facing portion. 101c is provided and the sealing material 101c
Is partially omitted to form a liquid crystal injection port 101d.

In this embodiment, both substrates 101a, 10a
Between 1b, no spacer is provided to keep the cell thickness constant. Subsequently, the liquid crystal display element 101 thus manufactured or a plurality of the liquid crystal display elements 101 already manufactured in such a manner are placed on the support 112 of the liquid crystal jig elevating / lowering mechanism 110.
01d are aligned and set as shown in FIG.

Next, the vacuum exhaust pump 105 is operated to evacuate the inside of the vacuum chamber 102, and the degree of vacuum is 1 to 3 × 1.
Evacuate below 0 ^-4 Torr. After that, the vacuum exhaust pump 105 is stopped, and the dispenser 120 filled with the defoamed liquid crystal in the liquid crystal tank 122 is operated by the control mechanism 121 to cause the inlets 101 of the plurality of liquid crystal display elements 101.
A predetermined amount of liquid crystal 122a is dropped near d. As the dropping amount, for example, a standard amount is twice the internal volume calculated based on the size of the liquid crystal display element 101 and the thickness of the liquid crystal layer. If there is little variation in the internal volume of each liquid crystal display element 101, a smaller amount may be used.

Next, the leak valve 103 is opened and nitrogen gas is introduced into the vacuum chamber 102. This causes a pressure difference between the inside of the liquid crystal display element 101 and the inside of the vacuum chamber 102. Simultaneously with the introduction of nitrogen gas, the liquid crystal is injected into the plurality of liquid crystal display elements 101.

Next, when the liquid crystal 122a is injected into all of the plurality of liquid crystal display elements 101 without containing bubbles, the liquid crystal jig elevating mechanism 110 is lowered and the lowermost liquid crystal display element 10 is moved.
1 is pulled out from the liquid crystal jig elevating mechanism 110 by the moving mechanism 124 and is conveyed to the liquid crystal layer thickness adjusting mechanism 130 side.
The liquid crystal display element 101 is set on the stage 131 below the liquid crystal layer thickness adjusting mechanism 130. When the setting is completed, the upper stage 132 is lowered by the elevating mechanism 133, and the liquid crystal display element 101 is moved to the stages 131 and 132.
Sandwich between. At this time, the stage 131 and the liquid crystal display element 10
1 is sealed by an O-ring 138a between the stage 132 and the liquid crystal display element 101.
38b creates a sealed state.

Next, the cell thickness of the liquid crystal display element 101 sandwiched between the stages 131 and 132 is measured. The cell thickness is measured by injecting liquid crystal into the liquid crystal display element 101,
The liquid crystal molecules are aligned in a TN (twisted nematic) orientation and function as an optical modulator. In the measurement method, the wavelengths of visible light rays are scanned through the polarizing plates by the optical fibers 137a and 137b embedded in the stages 131 and 132. It is calculated by evaluating the wavelength dependence of the intensity of transmitted light caused by this. This measured value is obtained by a computer provided in one of the cell thickness measuring devices 134a and 134b.

Next, the computer outputs a signal for driving one of the cell adsorption pumps 135a, 135b or the cell pressurizing compressors 136a, 136b according to the cell thickness. Specifically, as shown in FIG. 16, when the cell thickness is thin, the cell adsorption pumps 135a and 135b are used.
Is operated to suck and adsorb the liquid crystal display element 101 sandwiched between the stages 131 and 132 from both sides so that the cell thickness becomes large on the entire surface of the liquid crystal display element 101.

As a result, the liquid crystal 122a applied near the inlet 101d is sucked into the liquid crystal display element 101. The suction force can be finely adjusted by using the vacuum exhaust pump 105 and the leak valve 103 together. On the contrary, when the cell thickness is thick, as shown in FIG. 17, the cell pressurizing compressors 136a and 136b are operated to compress the liquid crystal display element 101 sandwiched between the stages 131 and 132 from both sides by compressed air. The pressure is applied to eject the liquid crystal 122a from the inlet 101d. Appropriate pressure is, for example, about 1 kg / cm ² . By doing so, the cell thickness of the liquid crystal display element 101 is adjusted. At the time of this adjustment, the cell thickness measuring device 134
a, 134b, continuously manage the cell thickness,
The cell thickness is controlled to a desired constant value.

Next, when the predetermined cell thickness is reached, an ultraviolet curable resin is applied to the injection port 101d, and this resin is irradiated with ultraviolet rays. This completes the sealing of the injection port 101d.

In this way, the first liquid crystal display element 1
When the sealing of 01 is completed, the completed liquid crystal display element 101
Is moved to the original position of the liquid crystal jig elevating mechanism 110 by the moving mechanism 124, and the second liquid crystal display element 101 is moved to the liquid crystal layer thickness adjusting mechanism 130 instead of being replaced.

The liquid crystal is injected into all the liquid crystal display elements 101 according to the procedure described above to manufacture the liquid crystal display elements 101.

As described in detail above, in the case of the manufacturing method of this embodiment, the thickness of the central portion of the liquid crystal layer injected between the two substrates 101a and 101b is measured. Based on this measurement result, the separation distance between the substrates 101a and 101b at the central portion between the two substrates 101a and 101b is mechanically adjusted. As a result, the liquid crystal 122a is injected or discharged from the injection port 101d, and the thickness of the central portion of the liquid crystal layer becomes a constant value.

FIG. 18 is a graph showing the cell thickness distribution of the liquid crystal display element manufactured by the manufacturing method of this embodiment together with the cell thickness distribution of the liquid crystal display element manufactured by the conventional manufacturing method. The measurement location of the cell thickness distribution is A- in FIG.
It is on the line A and on the diagonal line of the liquid crystal display element 101.
Note that line B in FIG. 18 is the case of the liquid crystal display element 101 manufactured by the manufacturing method of this embodiment, line C is the case where a spacer is interposed between the two substrates 101a and 101b, and line D is the case of two lines. When the liquid crystal is injected without interposing a spacer between the substrates 101a and 101b to increase the cell thickness, the line E indicates the two substrates 101a, 10b.
Liquid crystal is injected between 1b without interposing a spacer to reduce the cell thickness.

As can be understood from these figures, in the case of this embodiment, the accuracy of cell thickness adjustment is lower than in the case of interposing a spacer between the two substrates 101a and 101b, but the liquid crystal is simply injected. The cell thickness can be adjusted much more accurately than in the case shown by the lines D and E.

As described above, in the case of this embodiment,
Two substrates 10 opposed to each other without using a spacer
By maintaining the cell thickness between 1a and 101b at a uniform and constant value, it becomes possible to inject liquid crystal and seal the inlet of the liquid crystal display element 101. As a result, when the manufactured liquid crystal display element 101 is used in, for example, a projection projector to perform projection enlargement, there is no spacer as compared with the case of using a liquid crystal display element manufactured by a normal spacer dispersion method. In addition, the display quality was good without any display defects in which light was transmitted only through the spacer portion.

The third embodiment of the present invention is to manufacture a liquid crystal display element in which a gap in the display region is kept uniform without using a spacer. Conventionally, when a spacer is not arranged in a region other than the seal region, the display region is likely to be distorted, and the amount of the gap varies depending on the amount of injected liquid crystal, which increases the strain. Therefore, in order to manufacture a liquid crystal display element in which the display area is not distorted even after the liquid crystal is injected, a pair of substrates are fixed with a sealing material, and both substrates are removed from the empty cell state before the liquid crystal is injected. It is necessary to bond them with a gap as uniform as possible.

Hereinafter, reference will be made to FIGS. 19 and 20. The sealing material 202 including the spacer 203 is applied to one of the pair of substrates 201 and 204, the two substrates 201 and 204 are attached to the other substrate without spraying the spacers 203, and both are pressed by a pressing device. The substrates 201 and 204 are pressed against each other.

The means for pressing and holding is composed of a cushioning material having a cushioning effect on the pressure distribution and a pressing material having a smooth surface and high flexural strength. As the pressurizing material, a material having a surface waviness smaller than the surface waviness and a flexural strength equal to or higher than the flexural strength of the substrate is selected. The flexural strength is determined by the shape, size and material characteristics of the material, especially the longitudinal elastic modulus. Bonding is performed by pressing the entire surface of the substrate through a combination of a plurality of members having different characteristics.

By using the cushioning material, it is possible to absorb an element that causes unevenness in the distribution of the pressing force between the pair of substrates, such as uneven distribution of the pressing force by the pressing device, unevenness of the thickness of the substrates, and the like. The substrate can be pressed. Further, even if a load is applied to the entire surface of the substrate by the pressurizing material, it is possible to suppress the occurrence of deflection in the display area where the spacer is not present, and to effectively press only the seal area. At this time, in order to prevent the occurrence of uneven pressure distribution due to the presence of a compressive fluid such as air between the substrate and the pressure member, and to facilitate the separation of the substrate and the pressure member after pressing,
A process for forming a groove (slit) is performed on the surface of the pressure material.

With the pressing device as described above, ultraviolet rays are radiated while the pair of substrates are pressed against each other to temporarily cure the sealing material. At this time, since a small amount of flexure remains in the display area, as shown in FIG. 19, the gap is smaller inside the sealing material 202 than outside the sealing material 202. 202 is temporarily cured. Therefore, after the temporary curing, in order to soften the sealing material 202, it is heated to a temperature equal to or higher than the glass transition point of the sealing material 202.

At this time, the sealing material 202 is also cured (heat cured). That is, when the sealing material 202 is heated, when the temperature reaches the glass transition point or higher, the sealing material 202 softens. When the temperature is further increased, the softened sealing material 202 hardens. In the present embodiment, such softening and thermosetting of the sealing material 202 are performed in one continuous step.

By softening the sealing material 202,
By the restoring force of the substrates 205 and 208 generated by the bending, the shape of the sealing material 202 in FIG.
As shown in FIG. 0, it is possible to correct the deflection of the substrates 205 and 208 to a suppressed shape. In this state, the substrate 2
When 05 and 208 are cooled, the substrate 20 generated during pressing
It is possible to manufacture a liquid crystal cell in which the deflection in the display areas 5 and 208 is extremely small.

According to the manufacturing method of this embodiment,
A spacer is not required for controlling the cell gap, and a liquid crystal display device having a uniform gap can be manufactured.

The third embodiment of the present invention will be described in detail below with reference to the drawings.

The third embodiment will be described with reference to FIG. Upper and lower substrates 204 and 206 that are bonded to each other
As an example, a glass having an outer size of 150 × 150 mm and a thickness of 1.1 mm (7059 barium borosilicate glass manufactured by Corning, 6.89 × 10 ³ kg / mm ² longitudinal elastic modulus, surface waviness of 10 μm or less) is used. Four 3-inch liquid crystal display panels as shown by the seal pattern 22 were prepared. An electrode was formed on one surface of each substrate to control the electro-optical characteristics of the liquid crystal, an alignment film was formed, and the alignment treatment was performed by rubbing.

Sealing material 205 for bonding the upper and lower substrates
Is an epoxy acrylate-based UV curable resin, and has a resin property at 25 ° C. of a viscosity of 45,000 cp <5.
rpm> (Brookfield viscometer (HBT type) measurement) and a thixotropic index of 3.3 <0.5 rpm / 5 rpm value> were used. A glass fiber (PF-50S manufactured by Nippon Electric Glass Co., Ltd .: diameter 5.0 μm, length 15.0 μm) is used as the gap control spacer 208 mixed in the sealing material 205, and the mixing ratio is a seal. Material 2
It was adjusted to 50 mg per 1 g of 05. This sealing material 20
5 is applied to the bonding surface of the lower substrate 204 by screen printing along the seal pattern of the liquid crystal display panel.

Next, with the configuration shown in FIG.
The liquid crystal display panel was pressed. In the case of this embodiment, the pressing material is a quartz glass plate 203 (manufactured by Shin-Etsu Quartz Co., Ltd., longitudinal elastic modulus of 7.4 × 10 ³ kg / mm ² , surface waviness of 5 μm or less, outer dimensions of 150 × 150 mm, thickness of 3 mm). Was used. This quartz glass plate 203 has a pitch of 10 mm, a width of 0.05 mm, and a depth of 0.1 mm, as shown in FIG. 23, on the surface in contact with the substrate in order to prevent air from intervening between the quartz glass plate 203 and the substrate.
The slit 211 of No. 2 was formed by dicing.

The pressurizing material has a flexural strength Ee higher than the flexural strength Ea of the substrate 204 (Ee ≧ Ea) and a surface waviness R1 thereof smaller than the surface waviness Rw of the substrate 204 (R1 ≦ Rw). To use.

As the cushioning material 202, as an example, a sponge (made by Tigers Polymer, fluororubber sponge, external size 15
0 × 150 mm, thickness 7 mm) can be used.
This sponge is made of fluororubber foamed about 5 times, has excellent buffering property against pressure distribution, and is a material showing a characteristic curve of stress-strain characteristics extremely close to air as shown in FIG. As the cushioning material 202, a material obtained by foaming rubber or the like, which has characteristics similar to that of a fluid capable of uniformly transmitting pressure, has a uniform and fine and independent cell structure inside the material, or KCl, NaCl, or the like. Alkali halide crystal grains, or a fixed pressure medium such as pyrophyllite can also be used. The pressure medium may have any size and shape as long as it can sufficiently cover the seal pattern applied to the substrates 204 and 206.
It is desirable to have the same size and shape as.

The substrate 204, in the order shown in FIG.
207, the pressure medium is set in the pressing device, and the sealing material 20
5 is pressed until a predetermined gap determined by the spacer 208 included in No. 5 is reached. The pressing pressure of the pressing device is 0.9
It was set to kg / cm ² . In this way, the substrate 20
Liquid crystal display devices were manufactured by holding 4, 207 in a pressed state, irradiating ultraviolet rays UV from the surface plate 207, and temporarily curing the sealing material 205. In this embodiment, the substrate 20
While pressing No. 4 and 207 for 120 seconds, the ultraviolet irradiation was performed for 90 seconds in that state, and after the irradiation, it was held for 120 seconds only. Boards 204, 207
When the cell gap of the manufactured liquid crystal display panel was measured after pressing and the sealing material 205 was temporarily cured, the maximum amount of deflection in the vicinity of the central portion of the display area was about 0.6 μm.

In this state, as shown in FIG.
The pair of substrates 20 is arranged so that the inner gap of the liquid crystal display panel is smaller than the outer gap of the liquid crystal display panel.
The sealing material 205 is cured in a state in which Nos. 4 and 207 are bent. Firing was performed to soften the sealing material 205 to correct the shape of the sealing material 205 and to perform the main curing of the sealing material 205. Since the glass transition temperature Tg of the sealing material 205 used was 120 ° C., the firing conditions were a firing temperature of 150 ° C. and a firing time of 30 minutes. When the gap in the display area of the liquid crystal display panel after firing was measured, the variation with respect to the reference gap amount was ±
It was 0.15 μm.

By injecting liquid crystal into this liquid crystal display panel by a vacuum injection method, a liquid crystal display panel having a uniform gap almost equal to the state of an empty cell could be manufactured.

In the above-mentioned embodiment, even if a load is applied to the entire surface of the substrate 204 by pressing the entire surface of the substrates 204 and 207 through a plurality of pressure media,
The seal area 205 can be effectively pressed, the need to disperse spacers to the picture elements in the display area of the liquid crystal display panel is eliminated, and the gap can be held only by the seal area 205. As a result, it is possible to realize a liquid crystal display device having a high aperture ratio and a high contrast by preventing the occurrence of gap unevenness and the occurrence of display defects.

A first embodiment of the method of manufacturing a liquid crystal display device according to the present invention will be described below.

First, the sealing material used in this embodiment will be described. The material of the sealing material is an epoxy resin system, and has both an ultraviolet curing action and a thermosetting action.
The curing condition is 9 at wavelength of 365 nm in the case of UV curing.
Ultraviolet irradiation of 000 mJ is required. In the case of heat curing, it is necessary to bake at 150 ° C. for 30 minutes after UV curing.

The resin characteristic of the sealing material at 25 ° C. was 22 when measured by a Brookfield rotational viscometer (HBT type).
At 4,000 cP (5 rpm), the rocking index is 5.0
(0.5 rpm / 5 rpm value). In addition, the stress (σ (kgf / c
The m ² ))-cell gap (d (μm)) characteristic can be approximated by the first equation σ = Fd ⁿ . In this example, F = 1334 and n = 3.5, and the stress-cell gap characteristic is as shown by the curve in the graph of FIG. The target cell gap in this embodiment is, for example, 5 μm, and the pressing pressure is 4.8 kg / cm ² from the first formula.
Is decided.

The method of manufacturing the liquid crystal display element of this embodiment will be described below. 27 and 31 will be referred to. Corning 705 as the glass substrates 306 and 307
26, an a-Si TFT shown in FIG. 31 having a screen size of 3.0 inches is formed on the substrates 306 and 307 by using an outer size of 150 mm × 150 mm and a thickness of 1.1 mm.
Substrate equipped based on the seal pattern shown in (
A TFT substrate) 307 and a substrate (hereinafter referred to as a CF substrate) 306 having a color filter 328 are used as a pair.

First, an alignment film 326 made of polyimide resin is applied on the display areas of both substrates 306 and 307, and an alignment treatment is performed by a rubbing method. After that, the CF substrate 30
The above ultraviolet curable resin is applied onto 7 by a screen printing method in a seal pattern shown in FIG. A pattern 301 in FIG. 26 is a main body seal pattern of a liquid crystal display element, and a pattern 302 is a temporary fixing pattern for the substrates 306 and 307 in the process of bonding the substrates 306 and 307 to each other. Reference numeral 303 is a dummy pattern for the purpose of preventing bias of the pressing pressure applied to the sealing material in the pressing step.

The results of applying the sealing material are as follows.
The average height of the sealing material is 16 ± 2 μm, and the pattern width is 30.
It is 0 ± 20 μm. Under the above conditions, pressing to a cell gap of 5 μm results in a total seal area of about 2
It becomes 0 cm ² . From this result and the pressing pressure obtained from the first formula, the pressing load in the pressing step for controlling the cell gap becomes 96 kgf.

Next, on the TFT substrate 307, a conductive carbon resin is applied to the contact terminal portion to the counter electrode. Here, the viscosity of the conductive carbon resin used is 1 at 25 ° C. according to the above-described measuring device and measuring method.
The viscosity is 1,000 cP (5 rpm), which is sufficiently smaller than the viscosity of the ultraviolet curable resin.

A pair of glass substrates 30 subjected to the above treatment
6 and 307 are pasted together after positioning the picture element part,
A pair of substrates 30 that are bonded by irradiating ultraviolet rays only on the temporary fixing pattern 302 shown in FIG.
Fix them so that 6 and 307 do not shift from each other.

FIG. 27 shows an outline of a pressing device used in the pressing step for performing the next cell gap control. The press surface plates 309 and 310 of the press device are from room temperature to 50 ° C.
It is installed in a constant temperature bath 312 whose temperature can be controlled with an accuracy of ± 1.5 ° C. Further, one of the press surface plates 310 is provided with an ultraviolet irradiation device capable of irradiating the entire surface of the substrate 307 on the press surface plate 310 with ultraviolet rays. The irradiation device uses a high-pressure mercury lamp as a light source as an example, and emits ultraviolet rays having a wavelength of 365 nm at 60 m.
Ultraviolet rays can be irradiated at an intensity of W / cm ² . In addition, the pressure is applied to the other press platen 309.
In order to transmit evenly over the entire surface of 06, cushioning material 311
Is provided. The cushioning material 311 in this embodiment is
Fluorine rubber sponge 3 mm ^t manufactured by Tigers Polymer was used.

Substrates 306 and 307 are produced by the pressing device.
Temperature is set to 25 ± 1.5 ° C, and in this state, the first
Press with a pressing load of 96 kgf calculated from the formula. By maintaining this pressed state for 90 seconds, the sealing material 301,
303 becomes a steady state at the target cell gap.

Next, while the pressing is continued, ultraviolet rays are irradiated for 150 seconds to cause the sealing materials 301 and 303 to undergo an ultraviolet curing reaction. Since the ultraviolet curing reaction continues for about 90 seconds after the irradiation of ultraviolet rays, the pressing is continued for 120 seconds, and then the substrates 306 and 307 are taken out from the pressing device. Then, in order to cause the thermosetting reaction of the sealing materials 301 and 303, baking is performed in an oven at 150 ° C. for 30 minutes. In the main firing step, the glass transition temperature of the sealing materials 301 and 303 is higher than 120 ° C., and the hardening that relaxes the strain of the substrates 306 and 307 caused in the pressing step can be obtained. The maximum strain of the cell gap before and after firing in this example is 0.8 μm in the prior art,
It was improved to 0.4 μm.

Substrates 306 and 307 that have been bonded together
Is divided into the shape of the liquid crystal display element, and the liquid crystal 315 is injected by the vacuum injection method as shown in FIG. At this time, the liquid crystal 3
At the end of the vacuum injection step of No. 15, since there is no spacer in the liquid crystal layer of the liquid crystal display element, the substrate 30 corresponding to the area where the liquid crystal layer 315 is injected by the device shown in FIG.
Liquid crystal is forcibly injected into the liquid crystal display element by sucking the surfaces of 6, 307 with vacuum. At this time, the degree of vacuum for suction is measured while measuring the cell gap, and when the cell gap is within the range of 5 ± 0.15 μm, the liquid crystal remaining in the liquid crystal inlet is blown with N ₂ gas blower. After removing, the ultraviolet curable resin is applied to the injection port, and the ultraviolet curable resin is cured by spot irradiation of ultraviolet rays.

Through the above manufacturing steps, it was possible to manufacture a liquid crystal display device having a uniform cell gap without having any spacers.

A modification of the manufacturing method of the above embodiment will be described below.

The first method for manufacturing a liquid crystal display device
In the manufacturing process of the liquid crystal display element similar to that of the above embodiment, the buffer material used in the pressing device for pressing the pair of substrates 306 and 307 against each other may be a composite buffer material as shown in FIG. The composite cushioning material is used for equalizing the pressing load on the substrates 306 and 307. The first cushioning material 324 made of Tiger Rubber Co., Ltd. fluororubber sponge 7 mm ^t and the second cushioning material made of quartz glass 3 mm ^{t are used} . Cushioning material 3
25 and 25 are superposed. The second cushioning material 32
5 is manufactured by Shin-Etsu Quartz Co., Ltd. and has a longitudinal elastic member of 7.4 × 10 ³ kg /
mm ^2, the surface waviness The following materials were used 10 [mu] m. As shown in FIG. 30, one surface of the second cushioning material 325 has a pitch of 10 mm, a width of 0.05 mm, and a depth of 0.1 mm.
Slit 325a is formed by processing by dicing.

The slit 325a is an air vent for preventing pressure unevenness caused by air intervening between the substrate 306 and the second cushioning material 325, which are bonded together at the time of pressing.

According to the embodiment of the method for manufacturing the liquid crystal display device, the maximum strain of the cell gap at the end of the ultraviolet curing process of the sealing materials 301 and 303 is 0.6 μm.
In m, the maximum strain of the ants and the sealing materials 301 and 303 at the end of the firing step was 0.3 μm. When liquid crystal is injected into this liquid crystal display element, the cell gap is 5 ± 0.1.
μm, and it was possible to manufacture a liquid crystal display device in which variations in cell gap were further improved as compared with the case of the above-mentioned embodiment.

A second embodiment of the method of manufacturing a liquid crystal display device according to the present invention will be described below with reference to FIGS. 32 to 41. This embodiment is similar to the first embodiment, and the same reference numerals are given to corresponding parts.

A liquid crystal display element is prepared by a known manufacturing process of a liquid crystal display element. Here, as the glass substrate, 7059 glass manufactured by Corning and having a thickness of 1.1 mm is used. TFT substrate 40 in the first embodiment of the manufacturing method
3 and the counter substrate 402 are attached to each other, a sealing material 402 containing a thermosetting resin is applied to the counter substrate 402 by a seal printing method, and the TFT substrate 403 is provided with the above-mentioned pair without spacers. Substrates 402 and 403 are bonded together. In this embodiment, a thermosetting resin is used as the sealing material 402, and the glass fiber mixed for controlling the cell gap in the sealing material 402 has a diameter of 5.0 μm. The glass fiber was 50 mg per 1 g.

This bonded liquid crystal display element is installed in a pressing device, a load is applied to the sealing material 402, and the sealing material 402 is pretreated so that a predetermined cell gap is obtained.
Press so as to crush it to a thickness corresponding to the diameter of the glass fiber mixed with. Then, in order to cure the sealing material 402, it is baked in an oven at a temperature of about 170 degrees for 1 hour or more. As a result of measuring the air layer thickness of the display region surrounded by the sealant 402 of the liquid crystal display element thus created using a cell gap measuring device, the unevenness ratio in the display region is determined by the diameter of the glass fiber. The cell gap was within ± 5%. Then, the glass is divided to form a liquid crystal display element. The size of the liquid crystal display element is 3 inches, and its planar shape is shown in FIG.

In the liquid crystal injection method for the liquid crystal display element of this embodiment, first, as shown in FIG. 33, the required number of liquid crystal display elements 404 are set in the liquid crystal injection device 410 with the respective injection ports 406 oriented in the same direction. At the same time, the pouring pan 4 containing the liquid crystal 407 in an amount corresponding to the number of the set liquid crystal display elements.
Set 08. The inside of the vacuum chamber of the liquid crystal injection device 410 is evacuated to a degree of vacuum of 1 to 3 × 10 ⁻⁴ Torr.
And The defoaming process of the liquid crystal 407 in the vacuum chamber is sufficiently performed.

After that, the vacuum exhaust pump is stopped, and the vertically movable stage 409, on which the injection pan 408 containing the liquid crystal 407 is placed, is lifted, and the liquid crystal 407 is injected into the injection port 4.
Soak in 06. Then, open the leak valve 411,
Introduce nitrogen gas into the chamber.

At the same time when the nitrogen gas is fed, the liquid crystal 407 starts to be injected into the set liquid crystal display element 404. Here, the inside of the chamber is not returned to the atmospheric pressure all at once, but leaks at every 1 cmHg / mim. This work
The time from when the leak starts to 76 cmHg of the vacuum gauge of the liquid crystal injection device 410 until the atmospheric pressure is reached is about 76 mim.

After the pressure in the chamber returned to atmospheric pressure, one liquid crystal display element 404 was taken out and the thickness of the liquid crystal layer was measured. In the prior art, as shown in FIGS. 34 to 37,
Since there is no holding body for holding the cell gap between the TFT substrate 403 and the B / M substrate 402, the both substrates 402 and 403 may come into contact with or stick to each other (FIG. 35), or The cell gap becomes extremely small, and it takes a lot of time until the liquid crystal is completely injected.

On the other hand, as in the present embodiment, by controlling the pressure difference between the inside and the outside of the liquid crystal display element at the time of leakage after vacuum pumping, the results are as shown in FIGS. In this embodiment, the upper and lower substrates 402 and 403 are
Are prevented from contacting each other, damage to the alignment film is prevented, and defective injection is prevented. Also, the injection time of the liquid crystal 407 is shortened.

In the present embodiment, the cell gap immediately after the liquid crystal injection is thin, but by immersing the liquid crystal 407 in the liquid crystal 407 for about 4 hours and allowing it to stand naturally, it is the fastest and has the same layer thickness of 5.0 μm as the cell gap. It was possible to inject, and the cell gap could be controlled by the liquid crystal injecting time.

When several tens of liquid crystal display elements 404 leak to the atmospheric pressure all at once after the chamber is evacuated, the substrates 402 and 403 are contacted with each other in the display area of almost all the liquid crystal display elements 404. Each substrate 402,
403 remained adsorbed on each other. When 6.5 hours have passed after evacuation, the upper and lower substrates 40 are
2, 403 started to separate, but even after 10 hours, it was not possible to inject the same amount as the cell gap up to a layer thickness of 5.0 μm.

In the present invention, although it takes a relatively long time to reach the atmospheric pressure in the chamber, the final yield is improved and the total manufacturing time is longer than that in the conventional technique in which the atmospheric pressure is returned to the atmospheric pressure after evacuation. Can be shortened.
The relationship between the cell gap and the elapsed time is shown in the graph of FIG.

At the end of the manufacturing process, all the liquid crystal display elements 4 are
When the liquid crystal 407 is injected in 04, the liquid crystal attached to the injection port 406 of the liquid crystal display element 404 is sufficiently wiped off. Next, an ultraviolet curable resin is applied to the injection port 406, and after confirming that the injection port 406 is sufficiently covered, the resin is cured using an ultraviolet irradiation device,
The injection port 406 is sealed. And in the same procedure,
All the remaining liquid crystal display elements 404 are processed. As a result, the manufactured liquid crystal display device has a cell gap variation range within ± 5% with respect to 5 μm, which is an example of a layer thickness corresponding to a predetermined cell gap, as described above.
The cell gap can be controlled. In this way, the liquid crystal can be filled and the injection port can be sealed while the cell gap of the liquid crystal display element is kept uniform, and a liquid crystal display element with good display quality can be manufactured.
Further, the liquid crystal display element in which the liquid crystal is injected by controlling the pressure difference between the inside and the outside of the liquid crystal display element and the injection time of the liquid crystal,
Even a size of 1 inch or more can be easily manufactured without using a spacer. In addition, various problems as described above at the time of manufacturing can be solved together.

[0167]

As described above, according to the present invention,
Even if the spacer does not exist in the liquid crystal layer through which the modulated light passes, a liquid crystal display element having a uniform liquid crystal layer thickness and a small manufacturing error can be obtained. Defects can be eliminated, and particularly when used in a projection device or the like that performs enlarged image display, extremely high quality image display can be realized.

Also, a height of 5 μm is provided on both sides of the elastic sheet.
Since the unevenness of ˜30 μm and the cycle of 200 μm to 800 μm is formed, the pressure acting on the substrate is made uniform,
The adhesion of the spacer mixed in the sealing material and each substrate becomes uniform over the entire surface of the substrate, and the thickness error of the sealing material can be reduced.

In the case of the present invention, as described in detail, since the liquid crystal is injected while the cell thickness is controlled and the injection port is sealed, the cell thickness can be made uniform and a constant value. It is possible to provide a liquid crystal display element which can significantly improve the yield, has no display unevenness, and has high contrast and good display quality.

Further, in the pressing step for controlling the cell gap which is a manufacturing step of the liquid crystal display element, the pressure-cell gap characteristic with respect to the viscosity of the ultraviolet curable resin used as the sealing material is utilized to obtain the inside of the sealing material and the liquid crystal layer. It is possible to prepare a liquid crystal display device having a uniform cell gap without providing any spacers.

Further, according to the present invention, a liquid crystal display device having a uniform cell gap can be prepared without providing any spacer for controlling the cell gap.
Therefore, as in the conventional case, it is possible to prevent the problem of the reduction of the aperture ratio due to the spacer interposed in the liquid crystal layer and the deterioration of the display quality due to the poor alignment of the liquid crystal in the vicinity of the spacer, and the liquid crystal excellent in the display quality with high contrast. A display element can be created.

Even in the pressing step for controlling the cell gap,
Damage to the element or alignment film due to load concentration on the spacer, or cell gap unevenness due to reduced uniformity of stress distribution does not occur, so active elements for controlling the electro-optical effect of liquid crystal on the substrate, wiring materials, No defects occur in the alignment film and the like, the manufacturing yield is improved, and the display characteristics can be made uniform. Further, since the spacer is not required, the production process can be greatly simplified and the production cost can be reduced.

When the liquid crystal of the present invention is injected, the ultimate pressure of the internal and external pressures of the liquid crystal display element or the ultimate pressure of the external pressure and the fluctuation speed of the external pressure are adjusted.
When producing a liquid crystal display element in which a spacer is not present in the display region, the liquid crystal display element can be produced without causing damage to the alignment film or liquid crystal injection failure, and
The liquid crystal injection time can be shortened. Therefore, a liquid crystal display device having high contrast and good display quality can be produced.

[Brief description of drawings]

FIG. 1 is a plan view showing a liquid crystal display element of an embodiment of the present invention.

FIG. 2 is a sectional view taken along the section line AA of FIG.

FIG. 3 is a perspective view showing an example of an active matrix type color liquid crystal display device using the liquid crystal display element of FIG.

FIG. 4 is a plan view showing a coating state of a sealing material 4.

FIG. 5 is a cross-sectional view showing a pressing step of crushing the sealing material 4 between the first substrate 2 and the second substrate 3.

FIG. 6 is a partial cross-sectional view showing an example of an elastic sheet 33.

7 is a plan view showing a cutout shape of an elastic sheet 33. FIG.

8 is a partially enlarged view showing the relationship between the elastic sheet 33 and the sealing material 4 of FIG.

9 is a cross-sectional view showing a step of applying pressure to the first substrate and the second substrate with the elastic sheet 33 of FIG. 7 interposed.

10 is a partial cross-sectional view of the configuration of FIG.

FIG. 11 is a system diagram showing an example of a liquid crystal injection device 40.

FIG. 12 is a system diagram showing a liquid crystal injection device suitable for the method of the present invention.

13 is a side view of a jig 11 provided in the liquid crystal injection device of FIG.

14 is a front view of the jig 11. FIG.

FIG. 15 is a plan view showing the liquid crystal display element in a state where the liquid crystal display element manufactured by the manufacturing method of the present embodiment is partially manufactured.

FIG. 16 is a cross-sectional view showing a case where the cell thickness is adjusted by suction when the cell thickness is thin.

FIG. 17 is a cross-sectional view showing a case where the cell thickness is adjusted by applying pressure when the cell thickness is large.

FIG. 18 is a characteristic diagram showing a cell thickness distribution in the case of using various methods.

FIG. 19 is a substrate cross-sectional view.

FIG. 20 is a cross-sectional view of a substrate.

FIG. 21 is a cross-sectional view showing a pressing method using a plurality of pressure media.

FIG. 22 is a plan view showing a coating pattern of a sealing material on a substrate.

FIG. 23 is a perspective view showing slit processing of a pressure material.

FIG. 24 is a graph showing pressure-strain characteristics of a cushioning material.

FIG. 25 is a graph showing the pressure-cell gap characteristics of the epoxy UV curable resin used in this example.

FIG. 26 is a plan view showing a coating pattern of a sealing material.

FIG. 27 is a cross-sectional view showing the structure of a pressing device.

FIG. 28 is a cross-sectional view showing the configuration of a liquid crystal forced injection device for forcibly injecting liquid crystal into a liquid crystal display element.

FIG. 29 is a cross-sectional view showing the structure of a pressing device.

30 is a perspective view showing the shape of slits provided on one surface of the quartz glass of the cushioning material shown in FIG. 29. FIG.

FIG. 31 is a cross-sectional view of a liquid crystal display element created by the manufacturing method according to this embodiment.

FIG. 32 is a plan view of a liquid crystal display element according to an example of the present invention.

FIG. 33 is a cross-sectional view showing a state where a liquid crystal display element is set in the liquid crystal injection device.

FIG. 34 is a cross-sectional view of a liquid crystal display element showing a manufacturing process in contrast to this example.

FIG. 35 is a cross-sectional view of a liquid crystal display element showing a manufacturing process in contrast to this example.

FIG. 36 is a cross-sectional view of a liquid crystal display element showing a manufacturing process in comparison with this example.

FIG. 37 is a cross-sectional view of a liquid crystal display element showing a manufacturing process in comparison with this example.

FIG. 38 is a cross-sectional view of the liquid crystal display element showing the manufacturing process of this example.

FIG. 39 is a cross-sectional view of the liquid crystal display element showing the manufacturing process of this example.

FIG. 40 is a cross-sectional view of the liquid crystal display element showing the manufacturing process of this example.

FIG. 41 is a graph showing the relationship between the cell gap and the elapsed time between the above-mentioned contrast and this example.

FIG. 42 is a plan view showing an example of a conventional liquid crystal display element.

43 is a cross-sectional view taken along the section line GG of FIG. 42.

FIG. 44 is a cross-sectional view showing a conventional pressing method.

[Explanation of symbols]

 1 Liquid crystal display element 2 TFT substrate 3 Counter substrate 6 Liquid crystal layer 7 Injection port 102 Vacuum chamber 105 Vacuum exhaust pump 110 Liquid crystal jig lifting mechanism 124 Moving mechanism 130 Liquid crystal layer thickness adjusting mechanism

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroyuki Oue 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Prefecture Sharp Corporation (72) Inventor ▲ Taka Fuji Yu 22-22, Nagaike-cho, Abeno-ku, Osaka-shi, Osaka No. 22 within Sharp Corporation (72) Inventor Katsumi Nomura 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Prefecture Inside No. 22 (22) Masumi Kubo, 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Incorporated (72) Inventor Hirokazu Kamei 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka

Claims (14)

[Claims] 1. A liquid crystal display device comprising a liquid crystal layer sandwiched between a first substrate and a second substrate, wherein the first substrate and the second substrate are made of a sealing material containing no spacers. A liquid crystal display device which is fixed and in which a gap D between the first substrate and the second substrate and a film thickness d of the sealing material satisfy a condition of d <D. 2. The gap D and the film thickness d of the sealing material.
The liquid crystal display element according to claim 1, wherein and satisfy the condition of D ≦ 1.2 × d. 3. An area in which a sealing material mixed with a spacer for setting a gap between the first substrate and the second substrate is interposed between the first substrate and the second substrate, and the sealing material is arranged. An elastic sheet having a cut-out end on the first substrate and the second substrate.
A step of placing on the back surface of one of the substrates and pressurizing, a step of curing the sealing material, and a step of injecting liquid crystal into the space formed by the first and second substrates and the sealing material. A method for manufacturing a liquid crystal display device, including: 4. A height of 5 on both sides of the elastic sheet.
The method for manufacturing a liquid crystal display element according to claim 3, wherein irregularities having a period of 200 μm to 30 μm and a period of 200 μm to 800 μm are formed. 5. A step of providing a sealing material on a peripheral portion of two substrates arranged opposite to each other except a part thereof, and a liquid crystal injection port which is a part thereof is set with a larger amount of liquid crystal than a required liquid crystal injection amount. And a step of injecting the set liquid crystal between the two substrates due to a pressure difference between the inside and the outside of the two substrates, and a step of injecting liquid crystal into the center portion of the liquid crystal layer between the two substrates. A step of measuring the thickness, and a step of mechanically adjusting a separation distance between the two substrates at the central portion based on the measurement result of the thickness, and injecting or ejecting liquid crystal from the injection port, A method of manufacturing a liquid crystal display device, comprising the step of sealing the injection port. 6. A manufacturing method for manufacturing a liquid crystal display element, wherein a pair of substrates are fixed to each other by a sealing material, and liquid crystal is held between the pair of substrates. A step of applying a sealing material mixed with spacers for controlling a gap between the pair of substrates onto the substrates, and a sealing material without interposing a spacer for gap control in a display portion defined on the pair of substrates. A step of bonding the one substrate and the other substrate of the pair of substrates in a state where the gap between the pair of substrates is held by only the above, a step of curing the sealing material, and at least one display A method for manufacturing a liquid crystal display device, which comprises the steps of cutting the pair of substrates so as to form a cell, and injecting liquid crystal into the gap. 7. A pair of substrates are fixed to each other by a sealing material mixed with a spacer that determines a gap between the pair of substrates, and the spacer is arranged in a display region near the center of the gap between the substrates. In a manufacturing method for manufacturing a liquid crystal display device in which liquid crystal is held between the pair of substrates, a composite buffer material containing a plurality of pressure media is used to cover the entire surface of one of the pair of substrates. A method of manufacturing a liquid crystal display element, which comprises a step of pressing and a step of curing a sealing material and adhering the pair of substrates to each other in a pressed state. 8. In the pressure medium, at least one of a plurality of pressure mediums to be stacked has a smoothness equal to or higher than that of the pair of substrates bonded together, and the pressure mediums bonded together. The method for manufacturing a liquid crystal display element according to claim 7, wherein the pressure material has a flexural strength higher than that of the pair of substrates, and is arranged such that the smooth surfaces of the pair of substrates and the pressure medium are in contact with each other. 9. The surface of at least one of the pressure members,
8. A slit is formed to prevent trapping of air.
A method for manufacturing a liquid crystal display device according to item 1. 10. The method of manufacturing a liquid crystal display device according to claim 7, further comprising the step of heating the sealing material to a temperature equal to or higher than the glass transition temperature of the sealing material after curing. 11. A combination of UV-curing and heat-curing type, wherein a sealing material used for bonding the pair of substrates contains a polymerization reaction initiator activated by ultraviolet rays, and an unreacted reaction is activated by heat. The method for producing a liquid crystal display element according to claim 7, which is a resin composition. 12. A pair of substrates are fixed to each other by a sealing material containing a spacer that determines a gap between the pair of substrates, and the spacer is arranged in a display region near the center of the gap between the substrates. In a manufacturing method for manufacturing a liquid crystal display device holding a liquid crystal between the pair of substrates, the pressing force determined by at least one substrate of the pair of substrates based on a distance of a gap defined by a spacer. A method of manufacturing a liquid crystal display device, comprising: a step of pressing with a substrate; a step of applying a sealing material to one of the pair of substrates; and a step of curing the sealing material. 13. The viscosity and pressing stress of the sealing material are
The method for manufacturing a liquid crystal display element according to claim 12, which is determined based on viscosity dependency of stress-strain characteristics of the sealing material. 14. The first substrate and the second substrate are provided in a peripheral portion of the display region, which is disposed opposite to each other and in which the display region is defined, in at least one of the first substrate and the second substrate except the liquid crystal injection port. A step of providing a sealing material in which a spacer is mixed to determine the distance between the two substrates, a step of applying a vacuum to the inside and the periphery of the first and second substrates, and a liquid crystal is attached to the liquid crystal inlet. And a step of increasing the atmospheric pressure around the first substrate and the second substrate at a pressure change rate within a range that maintains the state in which the first substrate and the second substrate are separated from each other. Device manufacturing method.