JPH11133437A - Liquid crystal display element and projector the liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display(LCD) element capable of preventing the distortion of gap width generated due to sudden change of temperature and improviding the uniformity of a display picture in a high molecule dispersion type LCD element dispersing liquid crystal into a high molecular compound. SOLUTION: When spherical spacer 16 to be elastically compressed by two glass substrates 11, 12 is sprayed into a liquid crystal layer 17 held by the glass substrate 11 provided with voltage impressing means 18 to 21 and the other glass substrate 12 which are opposed to each other through a seal member 13 at a prescribed temperature range (e.g. 0 to 85 deg.C) and a prescribed ratio, the distortion of gap width between the glass substrates 11, 12 due to the variation of temperature in the prescribed temperature range can be prevented.

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 used for a liquid crystal display device or an optical shutter.

[0002]

2. Description of the Related Art Liquid crystal display elements are being put to practical use as large-screen, thin display devices in the field of information equipment mainly for portable personal computers and the field of video equipment mainly for televisions. ,recent years,
What is called a polymer dispersion type is drawing attention.

In this polymer-dispersed liquid crystal display device, a glass substrate with a pair of conductive films sandwiches a liquid crystal layer in which liquid crystals are dispersed in a water-drop or network-like manner in a polymer compound having a matrix-like structure. A state where incident light from a backlight or the like is transmitted and a state where light is scattered are switched based on whether or not voltage is applied to the liquid crystal layer.

[0004] A conventional technique will be described below with reference to the drawings. FIG. 9A is a cross-sectional view showing the structure of a conventional polymer-dispersed liquid crystal display device.

As shown in FIG. 9A, a liquid crystal display device 200 includes glass substrates 51 and 52 and a sealing member 53.
, Liquid crystal 54, polymer matrix 55, spacer 5
And 6.

The glass substrates 51 and 52 are glass substrates with transparent electrodes, which are conductive films made of ITO (indium tin oxide). The polymer matrix 55 is a polymer compound having a three-dimensional network structure. The liquid crystal 54 is a liquid crystal dispersed in a polymer matrix 55. Liquid crystal 54
And the polymer matrix 55, the glass substrates 51, 52
The liquid crystal layer 57 sandwiched therebetween is formed.

The sealing members 53 are made of glass substrates 51 and 52.
To seal the liquid crystal layer 57. Liquid crystal layer 57
A large number of spacers 56 are scattered on the glass substrate 51,
The gap width between 52 is kept constant. Glass substrate 51,
A voltage application unit (not shown) is provided in the unit 52, and applies a desired voltage to the liquid crystal layer 57.

Conventionally, in a polymer-dispersed liquid crystal display device, a spacer 56 having an average particle size smaller than the gap width between glass substrates is used, and the internal pressure of the liquid crystal layer 57 is set lower than the atmospheric pressure. You. This way,
Pressure acts on the liquid crystal layer 57 from the outside to the inside, and the gap width between the two glass substrates is maintained at the particle diameter of the spacer 56. The spacer 56 is the same as that used in the twisted nematic liquid crystal display device.

[0009]

In the above-mentioned conventional polymer-dispersed liquid crystal display device, the following problems occur due to a rapid change in temperature.

FIG. 9A shows a state of the liquid crystal display element 200 at a normal temperature (for example, 20 ° C.). In FIG. 9A, the spacer 56 receives almost no pressure from the glass substrates 51 and 52 because its size is the same as the gap width.

FIG. 9B shows a state of the liquid crystal display element at a high temperature (for example, 85 ° C.). In this case, the volume of the polymer matrix 55 and the liquid crystal 54 expands due to the heating, and the internal pressure of the liquid crystal layer 57 increases. Since the central portions of the glass substrates 51 and 52 are not fixed by the sealing member 53 unlike the peripheral portions, they deform as shown in FIG. 9B under the influence of the increased internal pressure, and approach the central portion from the peripheral portions. As the gap width increases, the gap width increases. As a result, the expanded liquid crystal concentrates on the central portion.

When the temperature is rapidly returned to the normal temperature from the state shown in FIG. 9B, the liquid crystal layer 57 contracts. At this time, the liquid crystal concentrated in the central portion cannot completely return to the original state, and most of the liquid crystal remains in the central portion. Therefore, FIG. 9 (c)
As shown in (2), the gap width between the glass substrates 51 and 52 is different in each part.

As described above, in the conventional polymer-dispersed liquid crystal display element, the thickness of the liquid crystal layer becomes abnormal due to the expansion and contraction of the liquid crystal layer due to a rapid change in temperature, and as a result, the display quality is drastically reduced. There was a problem that it deteriorated.

The present invention solves the above-mentioned conventional problems, and provides a liquid crystal display element which can prevent distortion of a gap width caused by a rapid change in temperature and can improve uniformity of a displayed image. The purpose is to:

[0015]

In order to solve the above-mentioned problems, a liquid crystal display device according to the present invention comprises a pair of opposing substrates having voltage applying means, at least one of which is transparent, and a pair of opposing substrates. What is claimed is: 1. A liquid crystal display device comprising: a liquid crystal layer to be sandwiched; and a plurality of spacers dispersed in the liquid crystal layer to maintain a uniform gap width between the opposing substrates, wherein the spacer repels in a predetermined temperature range. And the sum of the internal pressure of the liquid crystal layer and the repulsive force of the spacer is equal to the atmospheric pressure. With the above configuration, it is possible to prevent the gap width from being distorted due to a rapid change in temperature, and to improve the uniformity of the displayed image.

Further, a projection apparatus using the liquid crystal display element according to the present invention generates an image by controlling the degree of transmission of incident light from the light source using the light source, the screen, and the liquid crystal display element according to the present invention. It has a configuration including light control means and projection means for projecting the image on the screen. With the above configuration, it is possible to realize a projection device that enlarges and projects an image displayed on the liquid crystal display element by using the liquid crystal display element of the present invention.

[0017]

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

(Embodiment 1) FIG. 1 is a perspective view of a liquid crystal display device 100 according to a first embodiment of the present invention which achieves the first object. The liquid crystal display element 100 includes glass substrates 11 and 12, a sealing member 13, a liquid crystal 14,
, Polymer matrix 15, spacer 16, transparent electrodes 18 and 22, TFT element 19, gate signal line 2
0 and a source signal line 21.

The glass substrates 11 and 12, which are a pair of opposing substrates, are both transparent substrates made of glass. The polymer matrix 15 is a polymer compound having a three-dimensional network structure. The liquid crystal 14 is a liquid crystal dispersed in a polymer matrix 15 in the form of water droplets, or a liquid crystal having a network-like structure in which liquid crystals dispersed in the form of water droplets are connected to each other. A liquid crystal layer 17 sandwiched between the glass substrates 11 and 12 is composed of the polymer matrix 15 and the liquid crystal 14. The volume ratio between the liquid crystal 14 and the polymer matrix 15 in the liquid crystal layer 17 is approximately 4: 1.

The sealing member 13 is composed of the glass substrates 11 and 1
2 and seals the liquid crystal layer 17. The spacers 16 are spherical beads made of an elastic resin and colored in a light-shielding color such as black, and are scattered in the liquid crystal layer 17 in large numbers. Each of the spacers 16 has substantially the same particle diameter, and maintains a constant gap width between the two glass substrates while being elastically compressed by the glass substrates 11 and 12. The spacer 16 may be coated with SiO2 or the like in order to adjust physical properties such as elasticity. Hereinafter, resin beads or beads obtained by applying SiO2 or the like to resin beads are referred to as resin beads.

The use of a substance having a light-shielding property for the spacer 16 is such that the polymer-dispersed liquid crystal display element normally displays black when no voltage is applied, and at that time, light leaks through the spacer 16. This is to prevent them from leaving.

The transparent electrode 18 is a conductive film made of ITO provided on the glass substrate 11, and is a transparent electrode divided for each pixel of the liquid crystal display element 100. The transparent electrode 22 is a conductive film made of ITO provided on the glass substrate 12. The transparent electrode is common to all pixels of the liquid crystal display element 100.

The TFT (thin film transistor) element 19
T which is a switch means connected to each of the transparent electrodes 18
FT element. A gate signal line 20 and a source signal line 21 are connected to each of the TFT elements 19.

The transparent electrode 18, the TFT element 19, the gate signal line 20 and the source signal line 21 are formed on the liquid crystal layer 17 on the glass substrate 11, and the transparent electrode 22 is also formed on the liquid crystal layer 17 on the glass substrate 12. Formed. The glass substrate 11 as a pair of opposing substrates is formed from the transparent electrodes 18 and 22, the TFT element 19, the gate signal line 20 and the source signal line 21.
And 12 are configured as voltage applying means.

The liquid crystal display device 100 thus configured
In contrast, a gate signal and a source signal output from a drive circuit (not shown) are supplied to the TFT element 19 via a gate signal line 20 and a source signal line 21, respectively. When the TFT element 19 is turned on by the gate signal, the potential of the connected transparent electrode is set to a potential corresponding to the source signal. The transparent electrode 22 is set to a predetermined potential by a drive circuit (not shown). In this way, a voltage corresponding to the brightness of each pixel of the image to be displayed can be applied to the liquid crystal layer 17, and the image is displayed on the liquid crystal display element 100 upon receiving incident light from a backlight (not shown).

Referring to FIGS. 2 (a), 2 (b), 2 (c), and 3, a description will be given of the structure of the liquid crystal display element 100 according to the present invention caused by a rapid temperature change. Will be described.

First, FIG. 2A shows a state of the liquid crystal display element 100 at normal temperature (20 ° C. in the present embodiment). In this state, a pressure difference between the atmospheric pressure and the pressure of the liquid crystal layer 17 on the glass substrates 11 and 12 (hereinafter, referred to as the internal pressure of the liquid crystal layer 17) is applied to the two glass substrates from the outside. Is compressed.

FIG. 2B shows a state of the liquid crystal display element 100 in which the temperature of the liquid crystal display element 100 in the normal temperature state of FIG. 2A is raised to a high temperature (85 ° C. in the present embodiment). In this state, the internal pressure of the liquid crystal layer 17 is increased by heating. In the present embodiment, the linear expansion coefficient of the spacer 16 is 7.0 to 10.0 × 10 −5 (1 / K), and the linear expansion coefficient of the liquid crystal 14 is 7.0 × 10 −4 (1 / K). ), The coefficient of linear expansion of the polymer matrix 15 is equal to or less than the coefficient of expansion of the spacer 16. The liquid crystal 1 in the liquid crystal layer 17
The volume ratio between 4 and the polymer matrix 15 is approximately 4: 1. For this reason, the spacer 16 and the polymer matrix 1
5, the expansion of the internal pressure of the liquid crystal layer 17 due to heating depends on the expansion of the liquid crystal 14.

FIG. 3 shows a liquid crystal display element under a constant atmospheric pressure.
When the temperature of the child 100 is raised and lowered in a predetermined temperature range
The relationship between the internal pressure Pi of the liquid crystal layer 17 and the repulsion Pr of the spacer 16
An example of the relationship is shown. Note that, in FIG.
0kg / cm^TwoIt is. The horizontal axis ranges from 0 ° C to 85 ° C.
The temperature Temp in the box is shown. The vertical axis is 0.1 kg / cm ^Two
From 0.9kg / cm^TwoThe pressure P in the range between is shown. Real
The line L1 indicates the pressure applied to the liquid crystal layer 17, that is, the liquid crystal layer 17
And the dashed line L2 is applied to the spacer 16.
Pressure, that is, the repulsive force of the spacer 16 per unit area
Pr. Hereinafter, the spacer 16 per unit area
The repulsive force is simply referred to as the repulsive force Pr of the spacer 16.

In the above temperature range, both the internal pressure of the liquid crystal layer 17 and the repulsive force Pr of the spacer 16 exist, and the sum of them is equal to the atmospheric pressure. That is, in the liquid crystal display element 100, the internal pressure of the liquid crystal layer 17 and the repulsion P
r opposes atmospheric pressure.

When the internal pressure of the liquid crystal layer 17 increases in proportion to the temperature rise, the repulsive force Pr of the spacer 16 decreases.
In the temperature range (0 ° C. to 85 ° C.) in this example, the spacer 16 always has a repulsive force Pr. That is, the compressed spacer 16 pushes up the glass substrates 11 and 12 from the inside by the repulsive force Pr everywhere in the liquid crystal layer 17 to maintain the compressed state. As a result, as shown in FIG. 2B, the gap width is uniformly increased except for the peripheral portion fixed by the seal member 13.

FIG. 2C shows the liquid crystal display device 100 as shown in FIG.
FIG. 6B shows a state where the temperature is rapidly lowered from the high temperature state shown in FIG. When the liquid crystal display element 100 in a high temperature state is cooled as shown in FIG. 2B, the internal pressure of the liquid crystal layer 17 decreases and the repulsive force Pr of the spacer 16 increases. That is, the expanded liquid crystal layer 17 is formed by the glass substrates 11 and 12 and the spacer 1.
6 contracts while always in contact. Therefore, the liquid crystal layer 1
No. 7 shrinks uniformly as a whole without a difference in the degree of shrinkage depending on the location. As a result, even when the temperature is rapidly lowered from the high temperature state, as shown in FIG. 2C, it completely returns to the original state (FIG. 2A).

When the temperature of the liquid crystal display element 100 is lowered to a low temperature (0 ° C. in the present embodiment), the liquid crystal layer 1
7, the thickness Tc of the liquid crystal layer 17 is reduced by the repulsive force Pr of the spacer 16 as shown in FIG.
Is kept constant. In addition, even in the case of low temperature,
The internal pressure of the liquid crystal layer 17 exists, and the liquid crystal display element 100 opposes the atmospheric pressure by the internal pressure of the liquid crystal layer 17 and the repulsive force Pr of the spacer 16.

As described above, as long as the spacer 16 is elastically compressed, distortion of the gap width between the two glass substrates due to temperature fluctuation, that is, variation in the thickness Tc of the liquid crystal layer can be prevented. .

In this embodiment, the liquid crystal display element 1
00 has been described as a transmissive liquid crystal display element in which a pair of substrates provided with voltage applying means are both transparent glass substrates provided with transparent electrodes. In addition to the present embodiment, for example, if a reflective electrode that reflects light is used instead of the transparent electrode 22, a reflective liquid crystal display device having the effects of the present invention can be configured.

In order to form a reflection type liquid crystal display element, instead of the transparent electrode 18, a reflection electrode divided for each pixel is provided, and a voltage is supplied from the TFT element 19 to these reflection electrodes. It is also conceivable.

Further, in the present embodiment, the configuration using the TFT element as the switching means has been described.
Instead of the T element, an active element having a similar function, for example, M
An IM (Metal-Insulator-Metal) element or the like may be used. Of course.

Further, in the above description, the temperature range is from 0 ° C. to 85 ° C., but as long as the internal pressure of the liquid crystal layer 17 and the repulsive force Pr of the spacer 16 are present and the sum of them is equal to the atmospheric pressure, the effect of the present invention is obtained. Is obtained, and the present invention is not limited to the above temperature range. The reason for such a temperature range is that
This is because it is impossible to use the liquid crystal display device of the present invention at other temperatures as common sense.

(Embodiment 2) Hereinafter, referring to FIG.
A projection apparatus using a liquid crystal display device according to a first embodiment of the present invention that achieves the first object will be described. The projection device 150a according to the present embodiment includes a light source 30, a screen 33, a color filter 31, a projection lens 32 as a projection unit, and the liquid crystal display element 100 according to the first embodiment. It is arranged as follows. The liquid crystal display element 100 and the color filter 31 constitute a light transmission mechanism Lcu.

In FIG. 1, the liquid crystal display element 100 generates a grayscale image using white light emitted from the light source 30 according to a signal from a driving circuit (not shown) provided outside. In this sense, the liquid crystal display element 100 constitutes a density control mechanism Dcu. The gray image is converted into a color image by passing through the color filter 31. The color image from the color filter 31 is enlarged and projected on a screen 33 by a projection lens 32.

As described above, the projection device 150a according to the present embodiment uses the liquid crystal display element 100 to
3 can be enlarged and projected on the color image. In addition,
In FIG. 4, the color filter 31 is connected to the liquid crystal display element 1.
In the example shown between the light source 30 and the liquid crystal display element 100, the color filter 31 is provided between the light source 30 and the projection lens 32.
May be provided.

Hereinafter, with reference to FIG.
A modification of 50a will be described. In this example, the projection device 15
0b has three liquid crystal display elements 100R, 100G, and 100B having the same configuration as the liquid crystal display element 100 according to the first embodiment, similarly to the projection device 150a.
Further, the projection device 150b includes the light source 30 and the screen 3
3, dichroic mirrors 34a, 34b, 34c and 34d, and mirrors 35a and 35b, as shown in the figure.

The dichroic mirrors 34a and 34b and the mirror 35a constitute a color separation mechanism Csu.
The color separation mechanism Csu and the liquid crystal display elements 100R, 100G,
The light transmission mechanism Lcu ′ is composed of the density control mechanism Dcu ′ composed of the light transmission mechanism Lcu ′. Further, the mirror 35b and the dichroic mirrors 34c and 34d constitute a color combining mechanism Cmu, and the color combining mechanism Cmu and the projection lens 32 constitute a projection mechanism Pu.

The dichroic mirror 34a constituting the color separation mechanism Csu transmits the green (G) and blue (b) components of the white light from the light source 30, and reflects the red (R) component. The dichroic mirror 34b transmits the B component and reflects the G component among the G and B components transmitted by the dichroic mirror 34a. The mirror 35a is
The dichroic mirror 34b reflects the transmitted B component.

As a result, the liquid crystal display elements 100R, 100G, and 100B forming the density control mechanism Dcu 'include:
The primary color light of R, G, and B separated by the color separation mechanism Csu is irradiated. Liquid crystal display element 100R, 1
00G and 100B generate R, G, and B grayscale images, respectively, according to a signal from a driving circuit provided outside.

Mirror 35b constituting color synthesizing means Cmu
Reflects an R shaded image from the liquid crystal display element 100R. The dichroic mirror 34c is connected to the liquid crystal display element 10
It reflects the G grayscale image from 0G and transmits the R grayscale image from the mirror 35b. Dichroic mirror 34d
Reflects the grayscale image of B from the liquid crystal display element 100B and transmits the grayscale image of R and G from the dichroic mirror 34d.

As a result, the R, G, and B gray images are synthesized to generate a color image. The generated color image is enlarged and projected on a screen 33 by the projection lens 32.

As described above, the projection device 150b of the present invention
Is a screen 3 using three liquid crystal display elements having the same configuration as the liquid crystal display element 100 according to the first embodiment.
3 can be enlarged and projected on the color image.

In this embodiment, instead of providing the color synthesizing mechanism Cmu, a projection lens is provided for each of the RGB, and the grayscale image for each of the RGB is enlarged and projected at the same position on the screen 33, so that each of the RGB is provided. A configuration in which the grayscale image is synthesized on the screen may be adopted.

[0050]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments of the liquid crystal display device 100 according to the embodiment of the present invention will be described below in detail with reference to FIG.

Example 1 The spacers 16 scattered on the liquid crystal layer 17 had an average particle diameter of 8.98 μm and a standard deviation of 0.8.
34 μm resin beads were used. The spray density is 10 pieces /
It is about ² mm / mm ² to 300 pieces / mm ² .

A composite material composed of a substance (hereinafter, referred to as a polymer precursor) at a previous stage to become a polymer compound (polymer matrix) and a liquid crystal material is removed from the discontinuous portion of the seal member 13 by a vacuum injection method. After filling the space between the glass substrates 11 and 12, the sealing resin serving as a part of the seal member 13 is applied to the discontinuous portion of the seal member 13 while pressing the liquid crystal layer 17 so that the internal pressure becomes 0.35 kg / cm ^2. Is applied.

Next, the filled composite material of the polymer precursor and the liquid crystal material is irradiated with ultraviolet rays having an intensity of 50 mW / cm ² for 5 minutes, whereby the polymer is polymerized and the The material and the polymer compound phase-separated, and a liquid crystal layer 17 including the liquid crystal 14 and the polymer matrix 15 appeared. In this embodiment, the thickness Tc of the liquid crystal layer 17 is set to 8.5.
8 μm.

The liquid crystal display element 1 thus formed
When the image was displayed at 00, no display unevenness was observed in the state of normal temperature (20 ° C.) and in the state of normal temperature after heating once to high temperature (85 ° C.) and then cooling. Also,
Even at a high temperature, display irregularities were hardly observed because the thickness Tc of the liquid crystal layer 17 was substantially uniform. Further, when experiments were conducted by changing the type of the spacer 16 to be sprayed, it was found that resin beads were most effective.

In the following, referring to FIG.
Spraying density N of spacer 16 (pcs / mm^Two) And liquid crystal layer 17
Internal pressure Pi (kg / cm^Two) And the conditions
You. FIG. 6 shows that the application density N is 10 / mm^Two, 20 / mm^Two, 50 / mm^Two,
 100 / mm^Two, 150 / mm^Two, 200 / mm^Two, 250 / mm^Two, And 300 / mm^Two
, The internal pressure Pi of the liquid crystal layer 17 (Kg / c
m ^Two) On the horizontal axis, the density D of the compressed spacer 16
s (pc./mm^Three) Is shown on the vertical axis. The present invention
In other words, the density of the compressed spacers 16 is 10 pieces /
mm^TwoIf it is about, the liquid crystal layer 17 is heated and cooled.
The effect of absorbing variations in dimensional change was obtained.
6, the internal pressure Pi was set to 0.9 kg / cm.^TwoSet below
It turns out that it is good to set.

When the liquid crystal display element 100 is cooled from room temperature to a low temperature (0 ° C. in this embodiment), the liquid crystal layer 17 contracts and the internal pressure Pi decreases. In this case as well, FIG.
As in the case shown in FIG.
And the repulsive force Pr of the spacer 16 opposes the atmospheric pressure. The liquid crystal display element 10 configured as described above
In an experiment in which 0 was actually created, even when an image was displayed on the liquid crystal display element 100 in a low temperature state, display unevenness was hardly observed.

As described above, a predetermined temperature range (for example, 0
(From 85 ° C. to 85 ° C.), the internal pressure Pi of the liquid crystal layer 17.
(Kg / cm ² ) and the density N (pieces / m ² )
The condition regarding m ² ) is expressed by the following equations (1) and (2).

Pi ≦ 0.9 (1) 10 ≦ N ≦ 300 (2) More preferably, the density D of the compressed spacer 16
s is 20 pieces / mm ² or more. in this case,
The internal pressure Pi may be set to 0.7 kg / cm ² or less.

(Embodiment 2) In this embodiment, the thickness of the liquid crystal layer 17 is changed by using the same material and method as in Embodiment 1 except that the internal pressure P of the liquid crystal layer 17 is 0.3 kg / cm ^2. The liquid crystal display element 100 having Tc of 8.57 μm is formed.
The following results were obtained by an experiment conducted by actually manufacturing the liquid crystal display element 100 according to the present embodiment.

The liquid crystal display device 100 in this embodiment is
When heated to 5 ° C., the thickness Tc of the liquid crystal layer 17 became 8.98 μm, which is the same as the average particle diameter Dav of the dispersed spacers 16 due to the expansion of the liquid crystal 14 and the polymer matrix 15. At this time, the internal pressure Pi of the liquid crystal layer 17 is 0.82 kg / c.
m ² . Further, when an image was displayed on the liquid crystal display element 100, as in the case of the first embodiment, the room temperature (20 ° C.)
No display spots were observed in the condition (1) and the condition of normal temperature in which the material was once heated to a high temperature (85 ° C.) and then cooled. Further, even in a high temperature state, display unevenness was hardly observed because the thickness Tc of the liquid crystal layer 17 was substantially uniform.

When the liquid crystal display element 100 is cooled from room temperature to a low temperature (0 ° C. in this embodiment), the liquid crystal layer 17 contracts and the internal pressure Pi decreases. In this case as well, FIG.
As in the case shown in FIG.
And the repulsive force Pr of the spacer 16 opposes the atmospheric pressure. Therefore, even when an image was displayed on the liquid crystal display element 100 in a low temperature state, display unevenness was hardly observed.

FIG. 7 shows the relationship between the pressure Pp during sealing in the liquid crystal display element 100 and the distribution density Ds of the compressed spacers. In FIG. 7, similarly to FIG. 6, the application density N is 10 / mm ² , 20 / mm ² , 50 / mm ² , 100 / mm ² , 150 / mm ² ,
At 200 / mm ² , 250 / mm ² and 300 / mm ² respectively
However, the horizontal axis represents the internal pressure Pp (Kg / cm ² ) of the liquid crystal layer 17, and the density Ds (pc./
mm ³ ) is shown on the vertical axis.

As described above, the thickness Tc of the liquid crystal layer 17 at the upper limit temperature depends on the average particle diameter D of the spacer 16.
av. Further, as can be clearly read from FIG. 7, the internal pressure Pi of the liquid crystal layer 17 at the upper limit temperature is set to a predetermined temperature range so that the density Ds of the compressed spacers 16 becomes 10 pieces / mm ² or more. (For example, from 0 ° C to 85
Internal pressure Pi is 0.82 kg / cm ² (=
If Pi1) or less, no variation in display quality is observed.

Example 3 In this example, a liquid crystal display element 100 having a liquid crystal layer 17 having a thickness Tc of 8.24 μm was formed using the same material and method as those used in Example 1. When the liquid crystal display element 100 in this embodiment was heated to 85 ° C., the thickness Tc of the liquid crystal layer 17 was increased by the expansion of the liquid crystal 14 and the polymer matrix 15, and the average particle diameter Dav (= 8.98 μm) of the dispersed spacer 16 and the spacer Particle size D of 16
Is 8.64 μm, which is the same as the difference Dav−σ from the standard deviation σ (0.34 μm). The internal pressure Pi of the liquid crystal layer 17 at this time is
Was 0.65 kg / cm ² (= Pi2).

When an image was displayed on the liquid crystal display element 100 in this embodiment, the same as in the case of the first and second embodiments,
Normal temperature (20 ° C), and once heated to high temperature (85 ° C)
No display spots were observed at room temperature after cooling. Further, even in a high temperature state, the liquid crystal layer
Since the thickness Tc was almost uniform, display unevenness was hardly observed.

When the liquid crystal display element 100 is cooled from room temperature to a low temperature (0 ° C. in this embodiment), the liquid crystal layer 17 contracts and the internal pressure Pi decreases. In this case as well, FIG.
Similarly, the liquid crystal display element 100 opposes the atmospheric pressure by the internal pressure Pi of the liquid crystal layer 17 and the repulsive force Pr of the spacer 16. Therefore, even when an image was displayed on the liquid crystal display element 100 in a low temperature state, display unevenness was hardly observed.

As described above, the thickness Tc of the liquid crystal layer 17 at the upper limit temperature is substantially equal to the difference Dav-σ between the average particle diameter Dav of the spacer 16 and the standard deviation σ, and the internal pressure of the liquid crystal layer 17 at that temperature. Pi is 0.65 kg / cm
If it is ² (Pi2) or less, no variation in display quality is observed.

(Embodiment 4) In this embodiment, the thickness Tc of the liquid crystal layer 17 is determined using the same material and method as those used in Embodiment 1.
Was formed to form a liquid crystal display element 100 having a size of 7.92 μm.

The liquid crystal display device 100 in this embodiment is
When heated to 5 ° C., the thickness Tc of the liquid crystal layer 17 is increased by the expansion of the liquid crystal 14 and the polymer matrix 15, and the standard deviation σ between the average particle diameter Dav (= 8.98 μm) of the dispersed spacer 16 and the particle diameter D of the spacer 16 is obtained. (0.34μm) 2
The difference from the doubled value was 8.30 μm, which is the same as Dav-2σ. At this time, the internal pressure Pi of the liquid crystal layer 17 is 0.49 kg / c.
m ² (= Pi3).

When an image was displayed on the liquid crystal display device 100 in the present embodiment, as in the case of the first to third embodiments, it was in a state of normal temperature (20 ° C.), and once heated to a high temperature (85 ° C.) and then cooled. In the normal temperature state, no display spots were observed. Further, even in a high temperature state, display unevenness was hardly observed because the thickness Tc of the liquid crystal layer 17 was substantially uniform.

When the liquid crystal display element 100 is cooled from room temperature to a low temperature (0 ° C. in this embodiment), the liquid crystal layer 17 contracts and the internal pressure P decreases. Also in this case, the liquid crystal display element 100 includes the liquid crystal layer 1 as shown in FIG.
7 and the repulsive force Pr of the spacer 16 opposes the atmospheric pressure. Therefore, even when an image was displayed on the liquid crystal display element 100 in a low temperature state, display unevenness was hardly observed.

As described above, the thickness Tc of the liquid crystal layer 17 at the upper limit temperature is approximately equal to the difference Dav−2σ between the average particle diameter Dav of the spacer 16 and twice the standard deviation σ, and at that temperature. When the internal pressure Pi of the liquid crystal layer 17 is 0.
If it is 49 kg / cm ² (Pi3) or less, no variation in display quality is observed.

(Embodiment 5) In this embodiment, the internal pressure of the liquid crystal layer 17 is reduced to 0.3 by using the same material and method as used in the first embodiment.
kg / cm ² , the thickness Tc of the liquid crystal layer 17 is 7.92 μm.
m was formed. When the liquid crystal display element 100 in this embodiment was heated to 85 ° C., the thickness Tc of the liquid crystal layer 17 was 0.40 μm due to the expansion of the liquid crystal material.
m to 8.98 μm, which is equal to the average particle size Dav. At this time, the internal pressure of the liquid crystal was 0.56 kg / cm ² .

Here, the expansion coefficient of the liquid crystal material is α (1 /
K), the temperature range is Δt (K), and the thickness Tc of the liquid crystal layer 17 at 0 ° C. is Tc0 (μm), and the variation ΔTc (μm) of the thickness Tc of the liquid crystal layer 17 due to a change in temperature is
It is represented by

ΔTc = α · Δθ · Tc0 (3) Therefore, in this embodiment, the temperature range Δt is from 20 ° C. to 85 ° C.
Α is 7.0 × 10 −4 because the temperature is up to 65 ° C.

When an image was displayed on the liquid crystal display element 100 in the present embodiment, as in the case of the first, second, third and fourth embodiments, it was in a state of normal temperature (20 ° C.) and once heated to a high temperature (85 ° C.). ), And no display spots were observed in a state of cooling at room temperature. Also, even in high temperature conditions,
Since the thickness Tc of the liquid crystal layer 17 was substantially uniform, display unevenness was hardly observed.

When the liquid crystal display element 100 is cooled from room temperature to a low temperature (0 ° C. in this embodiment), the liquid crystal layer 17 contracts and the internal pressure P decreases. Also in this case, the liquid crystal display element 100 includes the liquid crystal layer 1 as shown in FIG.
7 and the repulsive force Pr of the spacer 16 opposes the atmospheric pressure. Therefore, even when an image was displayed on the liquid crystal display element 100 in a low temperature state, display unevenness was hardly observed.

In the case of this embodiment, it is desirable that the variation in the thickness Tc of the liquid crystal layer 17 is ± 0.21 μm, that is, within ± 2.5% of the average of the thickness Tc. The reason will be described below. Assuming that the applied voltage that gives a transmittance of 90% with respect to the saturated transmittance, which is the maximum transmittance of the liquid crystal display element, is V90, V90 of the liquid crystal display element 100 formed by the above-described material and method is 8. 2V.

FIG. 8 shows the transmission when a voltage of 8.2 V is applied to each of the liquid crystal display elements 100 manufactured by the method described in this embodiment by replacing the spacers 16 with various average particle diameters Dav. The relationship between the ratio Tr and the thickness Tc of the liquid crystal layer 17 is shown. Assuming that the variation of the transmittance Tr with respect to the thickness Tc of the liquid crystal layer 17 is ΔTr, it is empirically found that there is no practical problem if ΔTr is ± 8%. From FIG. 8, when the thickness Tc of the liquid crystal layer 17 is 8.58 μm, the allowable range of the variation of the thickness Tc is 8.55 ± 0.2.
It can be seen that it is 1 μm. That is, the allowable range of the variation ΔTc of the thickness Tc of the liquid crystal layer 17 is within ± 2.5% of the thickness Tc.

As described above, the thickness T of the liquid crystal layer 17 in the predetermined temperature range ΔT (for example, from 0 ° C. to 85 ° C.)
If the relationship of the following formulas 4 and 5 is established between c, the variation ΔTc of the thickness Tc, and the average particle diameter Dav of the spacer, the variation of the display quality is not observed.

ΔTc / Tc ≦ 0.025 (4) Tc + ΔTc ≦ Dav (6) (Embodiment 6) In this embodiment, the internal pressure of the liquid crystal layer 17 is reduced to 0 by using the same material and method as used in the first embodiment. .23kg / cm
^{At 2} , the liquid crystal display element 100 was formed in which the thickness Tc of the liquid crystal layer 17 was 8.24 μm. In this embodiment, as in the fifth embodiment, the thickness variation ΔTc is within ± 2.5% of the average of the thickness Tc, that is, the thickness Tc is 8.24 ± 0.2.
It is desirable that the thickness be 1 μm.

The liquid crystal display device 100 in this embodiment is
When heated to 5 ° C., the thickness Tc of the liquid crystal layer 17 is 0.40 μm due to expansion of the liquid crystal 14 and the polymer matrix 15.
The average particle diameter Dav of the spacer 16 (= 8.9)
8 μm) and the standard deviation σ (0.
34 μm), which is 8.64 μm, which is the same as Dav-σ. At this time, the internal pressure Pi of the liquid crystal layer 17 is 0.65 kg / c.
m ² .

When an image was displayed on the liquid crystal display element 100 in the present embodiment, Examples 1, 2, 3, 4, and 5 were displayed.
As in the case of the above, in a state of normal temperature (20 ° C.), and in a state of normal temperature in which heating is performed once to a high temperature (85 ° C.) and then cooled,
No visible spots were observed. Further, even in a high temperature state, display unevenness was hardly observed because the thickness Tc of the liquid crystal layer 17 was substantially uniform.

When the liquid crystal display element 100 is cooled from room temperature to a low temperature (0 ° C. in this embodiment), the liquid crystal layer 17 contracts and the internal pressure Pi decreases. In this case as well, FIG.
Similarly, the liquid crystal display element 100 opposes the atmospheric pressure by the internal pressure Pi of the liquid crystal layer 17 and the repulsive force Pr of the spacer 16. Therefore, even when an image was displayed on the liquid crystal display element 100 in a low temperature state, display unevenness was hardly observed.

As described above, the thickness T of the liquid crystal layer 17 in the predetermined temperature range Δt (for example, from 0 ° C. to 85 ° C.)
If the relationship of the above formulas 4 and 6 is established between c, the variation ΔTc of the thickness Tc of the liquid crystal layer 17 and the average particle diameter Dav of the spacer, no variation in the display quality is observed.

ΔTc / Tc ≦ 0.025 (4) Tc + ΔTc ≦ Dav-σ (6) (Embodiment 7) In this embodiment, the thickness of the liquid crystal layer 17 is determined by the same material and method as used in Embodiment 1. A liquid crystal display element 100 having a Tc of 7.92 μm was formed. In this embodiment, the thickness variation ΔTc is within ± 2.5% of the average of the thickness Tc, that is, the thickness Tc is 7.92 ± 0.20 μm, as described in the fifth and sixth embodiments. Is desirable.

The liquid crystal display device 100 of this embodiment is
When heated to 5 ° C., the thickness Tc of the liquid crystal layer 17 is 0.40 μm due to expansion of the liquid crystal 14 and the polymer matrix 15.
The average particle diameter Dav of the spacer 16 (= 8.9)
8 μm) and the standard deviation σ (0.
8.30 μm, which is the same as Dav-2σ which is twice as large as 34 μm)
It became. At this time, the internal pressure Pi of the liquid crystal layer 17 is 0.49 k.
g / cm ² .

When an image was displayed on the liquid crystal display element 100 in the present embodiment, it was at room temperature (20 ° C.) and heated once as in the case of the embodiments 1, 2, 3, 4, 5, and 6. No display spots were observed at room temperature after cooling to a high temperature (85 ° C.). Further, even in a high temperature state, since the thickness Tc of the liquid crystal layer 17 is substantially uniform,
Display spots were hardly observed.

When the liquid crystal display element 100 is cooled from room temperature to a low temperature (0 ° C. in this embodiment), the liquid crystal layer 17 contracts and the internal pressure P decreases. Also in this case, the liquid crystal display element 100 includes the liquid crystal layer 1 as shown in FIG.
7 and the repulsive force Pr of the spacer 16 opposes the atmospheric pressure. Therefore, even when an image was displayed on the liquid crystal display element 100 in a low temperature state, display unevenness was hardly observed.

As described above, the thickness T of the liquid crystal layer 17 in the predetermined temperature range Δt (for example, from 0 ° C. to 85 ° C.)
If the relationship between the above formula 4 and the following formula 7 is established between c, the variation ΔTc of the thickness of the liquid crystal layer 17 and the average particle diameter Dav of the spacer, no variation in display quality is observed.

ΔTc / Tc ≦ 0.025 (4) Tc + ΔTc ≦ Dav−2σ (7) (Eighth Embodiment) In this embodiment, the liquid crystal display element 100 of the first embodiment is formed and used in the first embodiment. The same composite material comprising a liquid crystal material and a polymer precursor as described above was filled from the discontinuous portion of the sealing member 13 by a vacuum injection method. After filling the composite material, the external pressure Pp into the glass substrate surface is 0.9.
A sealing resin was applied to the discontinuous portion of the seal member 13 so as to be kg / cm ² . The same sealing resin as in Example 1 was used.

Next, the composite material in the liquid crystal display element 100 is irradiated with ultraviolet rays having an intensity of 50 mW / cm ² for 5 minutes, so that the polymer precursor is polymerized and the liquid crystal material and the polymer compound are simultaneously converted. Was separated, and a liquid crystal layer 17 composed of the liquid crystal 14 and the polymer matrix 15 appeared.

When an image was displayed on the liquid crystal display element 100 in the present embodiment, Examples 1, 2, 3, 4, 5,
As in the cases of 6 and 7, no display spots were observed in the state of normal temperature (20 ° C.) and in the state of normal temperature after heating once to high temperature (85 ° C.) and then cooling. Further, even in a high temperature state, display unevenness was hardly observed because the thickness Tc of the liquid crystal layer 17 was substantially uniform.

In the following, the conditions of the spray density N (pieces / mm ² ) of the spacer 16 and the external pressure Pp (kg / cm ² ) obtained by subtracting the internal pressure of the liquid crystal layer 17 from the atmospheric pressure will be described. I do. In the present invention, if the density Ds of the compressed spacer 16 is about 10 pieces / mm ² , the effect can be obtained.
It is understood that p should be set to 0.1 kg / cm ² or more.

When the liquid crystal display element 100 is cooled from room temperature to a low temperature (0 ° C. in this embodiment), the liquid crystal layer 17 contracts and the internal pressure Pi decreases. In this case as well, FIG.
Similarly, the liquid crystal display element 100 opposes the atmospheric pressure by the internal pressure Pi of the liquid crystal layer 17 and the repulsive force Pr of the spacer 16. Therefore, even when an image was displayed on the liquid crystal display element 100 in a low temperature state, display unevenness was hardly observed.

As described above, the external pressure Pp in the predetermined temperature range Δt (for example, from 0 ° C. to 85 ° C.)
(Kg / cm ² ) and the density N (pieces / m ² )
The condition regarding m ² ) is expressed by the following equations 8 and 9.

0.1 ≦ Pp (8) 10 ≦ N ≦ 300 (9) More preferably, the density D of the compressed spacer 16
s is 20 pieces / mm ² or more. in this case,
The pressure Pp may be set to 0.3 kg / cm ² or more.

The present invention has been described in detail above. As the form of the liquid crystal and the polymer matrix in the polymer dispersion type liquid crystal display device, the liquid crystal in the polymer matrix as shown in the present embodiment is used. NCAP (Nemati
Instead of the c-Curvilinear-Aligned-Phase) type, the same applies when using a PN (Polymer-Network) type or the like, in which a polymer compound is dispersed in a three-dimensional network or microdroplets in a liquid crystal that forms a continuous phase. Can be implemented.

The spacer 16 in the above embodiment has an average particle diameter of 8.98 μm and a standard deviation of 0.34 μm.
However, similar effects can be obtained even if spacers of other materials, shapes and sizes are used as long as predetermined conditions for the spacers compressed at high temperature are satisfied.

In the above embodiment, the composite material of the polymer precursor and the liquid crystal material was filled in the liquid crystal display element by the vacuum injection method. Similar effects can be obtained by injecting a composite material.

[0101]

As described above, according to the liquid crystal display device of the present invention, the spacer having a predetermined density is compressed within the temperature range in which the liquid crystal display device is used. Distortion of the gap width between the glass substrates, that is, variation in the thickness of the liquid crystal layer can be prevented, and the uniformity of the displayed image can be improved.
Further, according to the projection device of the present invention, a uniform image can be enlarged and projected within the above temperature range.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing the structure of a polymer-dispersed liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 shows the polymer-dispersed liquid crystal display device shown in FIG.
(A) a normal temperature state, (b) a high temperature state, and (c) a cross-sectional view schematically showing a state when the temperature is returned from a high temperature to a normal temperature.

FIG. 3 is a diagram showing the relationship between the internal pressure of the liquid crystal layer and the repulsive force Pr of the spacer when the temperature of the liquid crystal display element is raised and lowered in a predetermined temperature range under a constant atmospheric pressure.

FIG. 4 is a block diagram schematically showing the structure of a projection device incorporating the polymer dispersed liquid crystal display device according to the first embodiment of the present invention.

FIG. 5 is a block diagram schematically showing a structure of a modification of the projection device shown in FIG. 4;

FIG. 6 is a diagram showing the relationship between the internal pressure of a liquid crystal layer and the distribution density of compressed spacers in a liquid crystal display element.

FIG. 7 is a diagram showing the relationship between the pressure at the time of sealing in a liquid crystal display element and the distribution density of compressed spacers.

FIG. 8 is a diagram showing a relationship between a voltage of 8.2 V, a thickness of a liquid crystal layer, and transmittance.

FIG. 9 shows a conventional polymer-dispersed liquid crystal display device 200;
(A) a normal temperature state, (b) a high temperature state, and (c) a cross-sectional view schematically showing a state when the temperature is returned from a high temperature to a normal temperature.

DESCRIPTION OF SYMBOLS 11, 12 Glass substrate 13 Seal member 14 Liquid crystal 15 Polymer matrix 16 Spacer 17 Liquid crystal layer 18 Transparent electrode 19 TFT 20 Gate signal line 21 Source signal line 22 Transparent electrode 30 Light source 31 Color filter 32 Projection lens 33 Screen 34a, 34b, 34c, 34, d Dichroic mirror 35a, 35b Mirror 51, 52 Glass substrate 53 Sealing member 54 Liquid crystal 55 Polymer matrix 56 Spacer 57 Liquid crystal layer 100, 100a, 100b, 100c, 200 Liquid crystal display element 150a, 150b apparatus

Claims (19)

[Claims] 1. A pair of opposing substrates having voltage applying means and at least one of them being transparent, a liquid crystal layer sandwiched between the pair of opposing substrates, and a gap between the opposing substrates dispersed in the liquid crystal layer. What is claimed is: 1. A liquid crystal display device comprising: a plurality of spacers for keeping a uniform width, wherein, in a predetermined temperature range, the liquid crystal layer has an internal pressure and the spacer has a repulsive force, and the internal pressure of the liquid crystal layer and the spacer A liquid crystal display element characterized in that the sum of the repulsion and the repulsion is equal to the atmospheric pressure. 2. The liquid crystal display device according to claim 1, wherein the liquid crystal layer comprises a polymer compound having a three-dimensional network structure, and a liquid crystal dispersed in the polymer compound. . 3. The internal pressure of the liquid crystal layer is approximately 0.9 kg / cm 2
3. The liquid crystal display device according to claim 2, wherein the scatter density of the spacer is about 10 to 300 pieces per 1 mm <2>. 4. The thickness Tc of the liquid crystal layer is substantially equal to the average particle diameter Dav of the spacer in the predetermined temperature range.
3. The liquid crystal display device according to claim 2, wherein: 5. The thickness Tc of the liquid crystal layer is approximately equal to the average particle diameter Dav of the spacer in the predetermined temperature range.
Dav-σ between the standard deviation σ of the particle diameter of the spacer and
3. The liquid crystal display device according to claim 2, wherein: 6. The thickness Tc of the liquid crystal layer is substantially equal to the average particle diameter Dav of the spacer in the predetermined temperature range.
3. The liquid crystal display device according to claim 2, wherein a difference between the difference and a value twice as large as a standard deviation σ of the particle diameter of the spacer is not more than Dav−2σ. 7. In the predetermined temperature range, the ratio of the absolute value of the variation ΔTc of the thickness Tc of the liquid crystal layer to the thickness Tc of the liquid crystal layer is approximately 2.5% or less, and the thickness Tc and the variation are different. 3. The liquid crystal display device according to claim 2, wherein the sum with ΔTc is substantially equal to or less than the average particle diameter Dav of the spacer. 8. In the predetermined temperature range, the ratio of the absolute value of the variation ΔTc of the thickness Tc of the liquid crystal layer to the thickness Tc of the liquid crystal layer is approximately 2.5% or less, and the thickness Tc and the variation 3. The liquid crystal display device according to claim 2, wherein the sum of .DELTA.Tc is approximately equal to or less than a difference Dav-.sigma. Between an average particle size Dav of the spacer and a standard deviation .sigma. Of the particle size of the spacer. 9. In the predetermined temperature range, the ratio of the absolute value of the variation ΔTc of the thickness Tc of the liquid crystal layer to the thickness Tc of the liquid crystal layer is approximately 2.5% or less. 3. The liquid crystal according to claim 2, wherein the sum of the variation [Delta] Tc is substantially equal to or less than a difference Dav-2 [sigma] between an average particle diameter Dav of the spacer and twice a standard deviation [sigma] of the particle diameter of the spacer. Display element. 10. The liquid crystal display device according to claim 1, wherein the spacer is a resin bead. 11. The liquid crystal display device according to claim 1, wherein the spacer has a light shielding property. 12. The liquid crystal display device according to claim 1, wherein the predetermined temperature range is approximately from 0 ° C. to 85 ° C. 13. The liquid crystal display device according to claim 1, wherein said pair of opposing substrates are transparent substrates having voltage applying means provided with transparent electrodes. 14. The voltage applying means, wherein at least one of the pair of opposed substrates is a transparent substrate, the transparent substrate is provided with a transparent electrode, and the other substrate is provided with a reflective electrode. The liquid crystal display device according to claim 1. 15. The device according to claim 13, wherein at least one of the electrodes included in the voltage applying unit includes a plurality of electrodes, and a switch unit is connected to each of the plurality of electrodes. Liquid crystal display element. 16. A light control means for generating an image by controlling the degree of transmission of incident light from the light source by using a light source, a screen, and the liquid crystal display element according to claim 13. A projection device using a liquid crystal display element, comprising: projection means for projecting onto the screen. 17. The liquid crystal display device according to claim 13, wherein the light control means generates a grayscale image from the incident light, and a color filter for converting the grayscale image into a color image. A projection device using the liquid crystal display device according to claim 16. 18. The light control means is provided with a color separation means for separating incident light from the light source into RGB primary colors, and the liquid crystal display element according to claim 13 for each of the primary colors. And a density control unit for controlling the degree of transmission of the primary color light from each of the primary colors to generate a grayscale image for each of the primary colors. 17. A projection device using the liquid crystal display device according to claim 16, wherein: 19. The color projector according to claim 19, wherein the projection unit combines a grayscale image for each of the primary colors to generate a color image, and a projection lens that projects the color image from the color combination unit onto the screen. 19. A projection device using the liquid crystal display element according to claim 18.