JP2009069422A - Liquid crystal display element and projection liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display element and a projection liquid crystal display which can prevent image quality defects due to light leakage of a spacer, has proper characteristics of contrast, or the like, and proper display performance. <P>SOLUTION: The liquid crystal display device has a liquid crystal layer arranged between two substrates, a plurality of pixel electrodes arranged on surfaces opposite to the respective substrates so as to form matrix-form pixels, oriented films formed on the two substrates so as to orient liquid crystal of the liquid crystal layer in a predetermined direction, and a spacer 46 formed between the pixel electrodes arranged adjacent in between the two substrates; and a pixel unit 50 is a three-pixel unit of a first pixel 51, a second pixel 52, and a third pixel 53 of red, green, and blue, and the spacer 46 is formed between the adjacent pixel units. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a liquid crystal display element having a spacer formed between adjacent pixel electrodes, and a projection type liquid crystal display device using the liquid crystal display element.

  Projection type display devices such as liquid crystal projectors can be roughly divided into two types: a three-plate type and a single-plate type.

  A three-plate projector, for example, as disclosed in Patent Document 1, separates light emitted from a light source into red, green, and blue, and each color light is configured by a liquid crystal display element (hereinafter referred to as LCD) 3 The light beams are modulated by the two light valves, and the modulated color light fluxes are synthesized again and enlarged and projected onto the projection surface. This method has a problem of high cost because the number of components, such as using three LCDs, increases.

In response to this problem, the single-plate projector has an advantage that low cost can be realized because only one LCD is required.
In a general single-plate projector, for example, there is a method of enlarging and projecting onto a screen using a color filter disclosed in Patent Document 2.
This method has an advantage that the optical system configuration is simple, the cost is low, and the system is compact.

  However, with this technology, due to the light absorption and reflection of the color filter, it is difficult to achieve high luminance due to poor light utilization efficiency, and the color filter such as resin has poor light resistance, and there is a concern that image quality may be deteriorated. There is.

In order to solve these problems, a light source as disclosed in Patent Document 3 is separated into red, green, and blue light beams by a dichroic mirror, and incident on the microlens array at different angles, corresponding to each. There has been proposed a single-plate display method in which the display pixels are distributed to such display pixels.
By using this display method, the light utilization efficiency is remarkably improved, and a display device with high luminance can be obtained.
As for light resistance, a long-life display device can be obtained by using a light-resistant polyimide film or inorganic film as the alignment film without using a color filter.

As a light valve mounted on the above liquid crystal projector or the like, an active matrix driving type LCD by driving a thin film transistor (hereinafter referred to as TFT) is generally used.
Most active matrix drive LCDs use nematic liquid crystals, and examples of display methods include twisted nematic (TN type) liquid crystals having a molecular arrangement twisted by 90 degrees.

In recent years, a vertical alignment type (VA type) liquid crystal element has been studied in order to increase the brightness, contrast, definition, and life of the liquid crystal projector.
This vertical alignment type liquid crystal display element is used for both transmission type and reflection type, and is expected to become the mainstream of liquid crystal projectors in the future along with the inorganicization of the alignment film for the purpose of extending the lifetime.

The two substrates on which the alignment films are formed are arranged so that the alignment films of the respective substrates are opposed to each other, and are bonded together with a sealing material around a display area where an image is actually displayed.
A liquid crystal cell is manufactured by forming a spacer for controlling the substrate gap and enclosing the liquid crystal.
Note that the above-described liquid crystal is composed of several types of single liquid crystal materials and is also called a liquid crystal composition. A polarizing plate is attached to the manufactured liquid crystal cell to manufacture a liquid crystal display element.
JP 60-169827 A JP 59-230383 A JP-A-4-316296

By the way, in recent years, with the miniaturization of projection display devices such as liquid crystal projectors, liquid crystal light valves have also been miniaturized. On the other hand, higher definition and higher brightness of pixels have been developed. As the definition becomes higher, the pixel pitch between liquid crystal display elements becomes smaller. Therefore, the range in which the light shielding portion is formed is becoming narrower.
For example, in the case of a 22.9 mm (0.99 inch) XGA (extended graphics array) type substrate, the number of pixels is 1024 × 768, and the pixel pitch is 6.5 μm in each single color pixel.

  A single-plate projector in which a light source as shown above is separated into red, green, and blue light beams by a dichroic mirror, incident on a microlens array at different angles, and distributed to display pixels corresponding to each. When the image is created with ultra high definition as described above, two problems occur.

The first is color mixing. As shown in FIG. 1, if each light beam enters each display pixel, there is no problem in image quality.
However, as shown in FIG. 2, there is a case where each light flux is incident outside the desired display pixel. In most cases, the light beams of the left and right pixels except the central pixel are incident on a part of the central pixel, that is, the colors of the central pixel are mixed.
This is mainly due to variations in the shape of the microlens and variations in the incident light angle.

The second is alignment failure. In the case of a high definition device, a very large lateral electric field is generated between two adjacent pixel electrodes.
The problem that alignment defects of liquid crystal molecules occur due to the influence of the lateral electric field is inevitable. As a countermeasure, narrowing the gap, that is, reducing the cell gap, and strengthening the vertical electric field between the TFT array substrate and the counter substrate. It is necessary to prevent the influence of the lateral electric field.
In particular, in the control of a narrow cell gap, columnar spacers are indispensable because even a small variation has a large effect on display quality.

However, in particular, in an LCD in which the above-described columnar spacers are formed, it is very difficult to control the orientation around the columnar spacers.
The region where the orientation control is weak cannot be oriented normally due to the influence of the transverse electric field, and the peripheral portion of the columnar spacer causes light leakage or the like.
When columnar spacers are produced in the vicinity of a pixel having mixed colors, it is easily predicted that the image quality is greatly reduced.

  An object of the present invention is to provide a liquid crystal display element and a projection type liquid crystal display device that can prevent image quality defects caused by light leakage of spacers, have good characteristics such as contrast, and have good display performance.

  A liquid crystal display element according to a first aspect of the present invention is provided on two opposing surfaces of each substrate so as to form two substrates facing each other, a liquid crystal layer disposed between the two substrates, and a matrix pixel. A plurality of pixel electrodes, an alignment film formed on the two substrates for aligning liquid crystals in the liquid crystal layer in a predetermined direction, and the pixel electrodes disposed adjacent to each other between the two substrates. A pixel unit is a three-pixel unit of a first pixel, a second pixel, and a third pixel formed of red, green, and blue, and the spacer is between adjacent pixel units. Is formed.

  A projection-type liquid crystal display device according to a second aspect of the present invention separates light emitted from a light source, a liquid crystal display element, and the light source into red, green, and blue light having different principal wavelengths. A condensing optical system that leads to the liquid crystal display element, and a projection optical system that projects the light modulated by the liquid crystal display element in an enlarged manner, and the liquid crystal display element includes two substrates facing each other. A liquid crystal layer disposed between the two substrates, a plurality of pixel electrodes disposed on opposite surfaces of each substrate to form a matrix-like pixel, and a liquid crystal of the liquid crystal layer for aligning the liquid crystal in a predetermined direction And an alignment film formed on the two substrates, and a spacer formed between the pixel electrodes disposed adjacent to each other between the two substrates, and the pixel unit is formed of red, green, and blue Three strokes of first pixel, second pixel, and third pixel A unit, the spacer is formed between adjacent pixels.

  Preferably, the spacer is formed at least between the first pixel and the third pixel.

  Preferably, the second pixel is a green pixel.

  Preferably, the spacer is disposed between the four adjacent pixel electrodes A1, A2, B1, and B2, and the four pixel electrodes are arranged on the front side A1, A2 and the own side B1 with respect to the alignment direction. , B2, the shortest distance (a) from the spacer center extension line to the pixel electrodes A1, A2 and the shortest distance (b) to the pixel electrodes B1, B2 are as follows: (a) ≦ (b) Satisfied.

  Preferably, the liquid crystal used in the liquid crystal layer has a refractive index anisotropy of 0.10 or more at room temperature and a thickness of the liquid crystal layer of 4 μm or less.

  Preferably, the liquid crystal panel provided with the pixel electrode is a transmissive type.

  Preferably, the pixel pitch of the single monochrome pixel is 20 μm or less.

  Preferably, the alignment film is formed of an inorganic alignment film.

According to the present invention, by optimizing the spacer layout design, it becomes difficult to visually recognize abnormal alignment and the like occurring in the pixel. Further, by suppressing the occurrence of image quality defects, high quality image quality can be obtained.
As a result, a high-quality liquid crystal display element can be realized.
In addition, in a projection type LCD such as a projector, it is possible to increase the aperture ratio by reducing the panel size or expanding the effective pixel area, and it is possible to realize high productivity and high yield by cell gap control. Since materials such as inorganic materials can be applied without degrading the image quality, the life can be extended.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 3 is a schematic configuration diagram showing an example of a projection display device that employs the liquid crystal display element according to the embodiment of the present invention.

  As shown in FIG. 3, the projection display apparatus PRJ includes a liquid crystal display element 1, a light source unit 2, a condenser lens 3, dichroic mirrors 4R, 4G, and 4B, a projection lens (projection optical system) 5, and a projection screen 6. It is configured as the main component.

In the liquid crystal display element 1, as shown in FIGS. 4A and 4B, a liquid crystal layer 13 is sandwiched between a transparent TFT array substrate 11 and a counter substrate 12 which is a transparent microlens array substrate ( Enclosed). In the counter substrate 12, a microlens array 133 is formed so as to be sandwiched between the cover glass 131 on the liquid crystal layer 13 side and the base glass 132 on the light incident side.
The configuration of the liquid crystal display element 1 will be described in detail later.

As the light source 2a of the light source unit 2 of the present embodiment, a high-pressure mercury lamp is used, but other lamps such as a metal halide lamp, a halogen lamp, and a xenon lamp can also be used.
A spherical mirror 2b is disposed on the back surface of the white light source 2a, and a condenser lens 3 is disposed on the front surface to make the white light source parallel light.

In front of the condenser lens 3 (light emission side), dichroic mirrors 4R, 4G, and 4B that are color separation optical systems that are color separation means for separating the light flux into red, green, and blue are provided. The dichroic mirrors 4R, 4G, and 4B, which are color separation optical systems, have characteristics that selectively reflect light in each wavelength band of red, green, and blue and transmit the others.
The red dichroic mirror 4G reflects visible light having a wavelength of about 600 nm or more, and the blue dichroic mirror 4B reflects short light having a wavelength of less than 500 nm. The green dichroic mirror 4G reflects a range of approximately 570-500 nm.

Due to the arrangement of the dichroic mirror, the light in the red wavelength region is reflected by the red dichroic mirror 4R and enters the microlens array 133 of the liquid crystal display element 1, and the light in the green wavelength region is transmitted through the red dichroic mirror 4R. , Reflected by the green dichroic mirror 4G, transmitted again through the red dichroic mirror 4R, and similarly incident on the microlens array 133 at different angles.
The light in the blue wavelength band is transmitted through the red and green dichroic mirrors 4R and 4G, then reflected by the blue dichroic mirror 4B, and again through the red and green dichroic mirrors 4R and 4G, and similarly to the microlens array 133. Incident at different angles.
Thus, the light of the single white light source 2a is separated into three color lights and is incident on the microlens array 133 from three directions.

  Below, the structure of the liquid crystal display element 1 which concerns on this embodiment is demonstrated in detail.

  FIG. 5 is a cross-sectional view showing a schematic configuration of the active matrix liquid crystal display element according to the present embodiment.

As shown in FIG. 5, the liquid crystal display element 1 according to the present embodiment has a TFT array substrate (substrate on which an active element is formed) 11 and a transparent microlens array substrate opposed to the TFT array substrate 11. And a substrate 12.
For example, in the case of a transmissive type, the TFT array substrate 11 is provided with a pixel electrode 14. The pixel electrode 14 is formed of a transparent conductive thin film such as an ITO film (indium tin oxide film).
The counter substrate 12 is provided with the above-described entire ITO film (counter electrode) 15 on the front surface.
An alignment film (not shown) for aligning liquid crystals in a predetermined direction is formed on the TFT array substrate 11 and the counter substrate 12, and a pair of layers bonded together with a sealing material 16 so that the alignment films face each other with a predetermined gap. For example, a liquid crystal layer 13 is sandwiched (enclosed) between the substrates.

  FIG. 6 is a diagram showing an arrangement example of the active matrix liquid crystal display element according to the present embodiment on the array substrate (liquid crystal panel unit).

As shown in FIG. 6, the liquid crystal display element 1A includes a pixel display region 21 in which pixels are arranged in an array, a horizontal transfer circuit 22, vertical transfer circuits 23-1 and 23-2, a precharge circuit 24, and a level converter. The circuit 25 is formed.
In the pixel display area 21, a plurality of data lines 26 and a plurality of scanning lines (gate wirings) 27 are wired in a grid pattern. One end of each data line 26 is connected to the horizontal transfer circuit 22, and the other end is precharged. Connected to the circuit 24, the end of each scanning line 27 is connected to the vertical transfer circuits 23-1, 23-2.

A plurality of pixels PX that are formed in a matrix that forms the pixel display region 21 of the liquid crystal display element 1A are provided with a pixel switching transistor 28 that controls switching, a liquid crystal 29, and an auxiliary capacitor (storage capacitor) 30.
A data line 26 to which a pixel signal is supplied is electrically connected to the source of the transistor 28 and supplies a pixel signal to be written. In addition, the scanning line 27 is electrically connected to the gate of the transistor 28, and the scanning signal is applied to the scanning line 27 in a pulse manner at a predetermined timing.
The pixel electrode 14 is electrically connected to the drain of the transistor 28. By turning on the transistor 28, which is a switching element, for a certain period, the pixel signal supplied from the data line 26 is transmitted at a predetermined timing. Write pixel signal.

A pixel signal of a predetermined level written to the liquid crystal 29 through the pixel electrode 14 is held for a certain period with the counter electrode formed on the counter substrate 12. The liquid crystal 29 modulates light and enables gradation display by changing the orientation and order of the molecular assembly according to the applied voltage level.
In the case of normally white display, incident light can pass through the liquid crystal portion according to the applied voltage, and light having a contrast corresponding to the pixel signal is emitted from the liquid crystal display element as a whole.
Here, in order to prevent the held pixel signal from leaking, an auxiliary capacitor (storage capacitor) 30 is added in parallel with the liquid crystal capacitor formed between the pixel electrode and the counter electrode. Thereby, the retention characteristics are further improved, and a liquid crystal display element with a high contrast ratio can be realized.
In addition, in order to form such a storage capacitor (storage capacitor) 30, a resistance common wiring 31 is provided.

FIG. 7 is a cross-sectional view showing a specific configuration example of the active matrix type liquid crystal display element according to the present embodiment.
A manufacturing method of the active matrix type liquid crystal display element according to this embodiment will be described with reference to FIG.

First, a high melting point metal (WSi in this embodiment) is formed as the first light shielding film 32 on the TFT array substrate 11 made of quartz.
Thereafter, SiO ₂ is laminated as the first interlayer film 33, a polycrystalline Si film (p-Si) 34 is formed using a CVD method, and a pattern is formed by etching.
Thereafter, a gate insulating film 35 is formed, a polycrystalline Si film (p-Si) is formed as the gate electrode 36, and a pattern is formed by etching.
Thereafter, SiO ₂ is laminated as the second interlayer film 37, and the first contact 38 is formed as the source and drain electrodes.
A metal material (Al in the present embodiment) is formed as the first wiring film 39 by film formation such as sputtering, and patterning is performed by etching.
Thereafter, SiO ₂ is laminated as the third interlayer film 40 and the second contact 41 is formed, and then a metal film (Ti in this embodiment) is formed as the second light shielding film 42.
SiO ₂ is laminated as the fourth interlayer film 43, the third contact 44 is formed, and ITO is formed as the transparent electrode 45.
Next, a transparent resist layer to be the columnar spacer 46 is formed.
After applying a photoresist to a predetermined thickness on the substrate, an exposure process by ultraviolet irradiation is performed using a photomask, followed by development and baking to form columnar spacers 46. The columnar spacer 46 is disposed at a desired position between adjacent pixel electrodes.
Next, the fabricated TFT array substrate 11 and counter substrate 12 are washed.
Next, an alignment film is formed on each substrate.
Next, rubbing is performed so as to obtain a predetermined orientation, a seal pattern is formed except for the injection port, and a liquid crystal composition is injected.

In the liquid crystal display elements 1 and 1A according to the present embodiment formed in this way, as shown below, by devising the arrangement position (formation position) of the columnar spacer, an alignment abnormality or the like occurring in the pixel is generated. It becomes difficult to see and suppresses the occurrence of image quality defects, so that high-quality image quality can be obtained and a high-quality liquid crystal display element is realized.
Hereinafter, the arrangement position (formation position) of the columnar spacers of the liquid crystal display elements 1 and 1A of the present embodiment will be described.

In the liquid crystal display elements 1 and 1A of the present embodiment, the pixel unit 50 is a three-pixel unit of a first pixel 51, a second pixel 52, and a third pixel 53 that are formed of red, green, and blue as shown in FIG. The spacer 46 is formed between adjacent pixel units 50.
The spacer 46 is formed between the first pixel 51 and the third pixel between the adjacent pixel units 50. If the columnar spacer 46 is arranged in the vicinity of the mixed color pixel, the image quality is deteriorated due to poor alignment in addition to the mixed color. . Only by devising not to arrange the columnar spacer 46 at the central pixel where color mixing is likely to occur, image quality and yield can be greatly improved.
In the present embodiment, the first pixel 51 is a red pixel (PX) R, the third pixel 53 is a blue pixel (PX) B, and the second pixel 52 located at the center in the pixel unit 50 is a green pixel PXG. It is.
Focusing on human visibility, among the red, green, and blue pixels, image quality degradation due to light leakage caused by columnar spacers is overwhelmingly visible on green pixels. This is because the human eye has different ways of feeling brightness depending on the wavelength of light. In general, how to perceive brightness is called visual sensitivity, but as shown in FIG. 9 (specific visual sensitivity of photopic vision of CIE photometric standard observer), the human eye looks at light with a wavelength of 555 nm. I feel the most.
That is, it can be seen that the visibility of light leakage is dramatically improved by arranging the columnar spacers 46 avoiding the green pixels PXR.

  Further, in the present embodiment, as shown in FIG. 10, the columnar spacer 46 is arranged between the four adjacent pixel electrodes A1, A2, B1, and B2, and the four pixel electrodes are arranged on the front side with respect to the alignment direction. When defined as A1, A2, self-stage side B1, B2, the shortest distance (a) from the spacer center extension line CL to the pixel electrodes A1, A2 and the shortest distance (b) from the pixel electrodes B1, B2 are ( The relationship of a) ≦ (b) is satisfied.

As a design parameter for alignment failure, lateral electric field control is important, and alignment control of the peripheral portion of the spacer is very important.
In the case of a narrow-pitch high-definition device, as described above, the alignment disturbance due to the reverse tilt domain due to the transverse electric field is in a very severe direction. As a countermeasure, it is effective to reduce the cell gap and increase the vertical electric field. However, since it is difficult to control the narrowing of the gap, it is very effective to arrange a spacer.
In the case of controlling the alignment, the spacer has a large step, and the downstream portion in the alignment direction becomes a shadow, thereby generating a region where the alignment is not controlled at all.
For example, when the alignment control is performed by rubbing or the like, a higher-quality display can be realized by arranging the spacers so that a portion that is downstream (shadow) of rubbing does not cover the pixel portion.
In particular, since the pixel electrodes B1 and B2 side are downstream portions of the rubbing, spacers are arranged near the pixel electrodes A1 and A2.

The liquid crystal display elements 1 and 1A according to the present embodiment having the spacers formed at the characteristic arrangement positions as described above are suitable for a transmissive liquid crystal panel, for example.
In particular, when rubbing is used for alignment control, alignment control around the spacer is very difficult due to the presence of steps. The present invention is very effective for the alignment control method using rubbing.
The liquid crystal used for the liquid crystal layer is characterized in that the refractive index anisotropy at room temperature is 0.10 or more and the cell gap is 4 μm or less.
The pixel pitch of the liquid crystal display element is 20 μm or less, and an inorganic alignment film can be used as the alignment film.

In particular, a liquid crystal projector is a narrow-pitch, high-definition device, and further enlarges and projects, so image quality abnormalities are easily noticeable.
The orientation disturbance due to the reverse tilt domain due to the lateral electric field is in a very severe direction. As a countermeasure, it is also effective to narrow the gap, that is, to thin the cell gap, to strengthen the vertical electric field between the TFT array substrate and the counter substrate, and to prevent the influence of the horizontal electric field.
For narrowing the gap, it is very effective for gap control to create a selective spacer especially in the light shielding portion. In order to obtain the maximum transmittance characteristic, it is necessary to increase the refractive index anisotropy Δn of the liquid crystal when the above-described measures are taken to reduce the cell gap.
For example, when a TN alignment cell is placed under crossed Nicols (transmittance when the voltage is OFF in TN alignment), it is as follows.

[Equation 1]
T = 1- [sin2 ((1 + u2) 1/2 x π / 2)] / (1 + u2)
u = 2Δnd / λ

・ If (1 + u2) 1/2 = 2n, the maximum value is reached.
・ Maximum when Δnd = (4n2 −1) 1/2 × (λ / 2).
So you get the following relationship

[Equation 2]
1stΔnd = √3 × (λ / 2)

From the above formula, the maximum transmittance design for green light (550 nm) is Δnd = 0.48 μm. For example, when the cell gap is 4 μm or less, Δn = 0.12 or more is required.
In recent years, inorganic alignment films that are resistant to light, which are advantageous for projectors, and have a long life expectancy have been studied. Inorganic alignment film materials often have a smaller alignment regulating force than ordinary organic materials such as polyimide, and are more susceptible to electric field forces. Therefore, the effectiveness of the present invention can be exhibited.

  Examples of the present invention are shown below.

Example 1 Formation of Spacer As shown in FIG. 7, a transparent resist layer to be a columnar spacer 46 was formed. After applying PMER (manufactured by Tokyo Ohka Kogyo Co., Ltd.) as a photoresist on the substrate to a thickness of 3 μm by spin coating, exposure is performed by ultraviolet irradiation using a photomask, followed by development and baking. To form columnar spacers having a diameter of about 1.5 μm.
The spacer arrangement position is as shown in FIG. 11 and Table 1.

  In this case, in the embodiment of the present invention, the spacer 46 is disposed between the third pixel (B) 53 and the first pixel (R) 51, and the shortest distance from the spacer center extension line CL to the pixel electrodes A1, A2 is. The shortest distance (b) between (a) and the pixel electrodes B1, B2 satisfies the relationship of (a) <(b).

Table 1 also shows comparative examples <1> to <4>.
In the comparative example <1>, the spacer 46 is disposed between the first pixel (R) 51 and the second pixel (G) 52, and the shortest distance (a) from the spacer center extension line CL to the pixel electrodes A1 and A2 And the shortest distance (b) between the pixel electrodes B1 and B2 satisfies the relationship (a) <(b).
In the comparative example <2>, the spacer 46 is disposed between the second pixel (G) 52 and the third pixel (B) 53, and the shortest distance (a) from the spacer center extension line CL to the pixel electrodes A1, A2. And the shortest distance (b) between the pixel electrodes B1 and B2 satisfies the relationship (a) <(b).
In Comparative Example <3>, the spacer 46 is disposed between the third pixel (B) 53 and the first pixel (R) 51, and the shortest distance (a) from the spacer center extension line CL to the pixel electrodes A1 and A2 And the shortest distance (b) between the pixel electrodes B1 and B2 satisfies the relationship (a) = (b).
In the comparative example <4>, the spacer 46 is disposed between the third pixel (B) 53 and the first pixel (R) 51, and the shortest distance (a) from the spacer center extension line CL to the pixel electrodes A1 and A2. And the shortest distance (b) between the pixel electrodes B1 and B2 satisfies the relationship (a)> (b).

Next, the TFT array substrate 11 and the counter substrate 12 are cleaned. Next, an alignment film was formed on each of the substrates 11 and 12. An organic material made of polyimide was used for the alignment film. The film was applied by spin coating so that the film thickness was 50 nm. Pre-baking was performed on a hot plate, and then post-baking was performed.
Next, rubbing was performed to form a seal pattern except for the injection port, and a liquid crystal composition was injected. The liquid crystal composition used had a refractive index anisotropy Δn at room temperature of 0.16 so that the transmittance of green light was theoretically maximized at a gap of 3 μm. Image quality evaluation by projection was performed on the manufactured liquid crystal display element.

When the spacer was arranged between the green pixel R which is the second pixel as in Comparative Examples <1> and <2>, the light leakage was noticeable and the image quality was greatly lowered.
The comparative examples <3> and <4> in which the spacers are arranged close to the self-stage side are better than the comparative examples <1> and <2>. However, although the comparative example <4>, the light leakage was conspicuous.
Therefore, the shortest distance (a) from CL on the spacer center extension line to the pixel electrodes A1 and A2 and the shortest distance (b) to the pixel electrodes B1 and B2 must satisfy the relationship of (a) ≦ (b). Is

<Example 2> ... Inorganic material In the above-described alignment film formation, an inorganic alignment film was used instead of the organic material. Although silicon etc. which are typically formed by vapor deposition are mentioned, it is thought that almost all substances which can be formed into a film by vapor deposition, such as a simple substance or a mixture or a compound of group IV elements such as germanium can be used.
In addition, a material having a siloxy acid skeleton formed by printing, spin coating, or an ink jet method may be used. An alignment film was formed on each substrate.
Each substrate was introduced into a vapor deposition apparatus, and each was formed by oblique vapor deposition of SiO ₂ as an alignment film. The film thickness was applied to a thickness of about 50 nm. Next, a seal pattern formed except for the injection port was formed. The liquid crystal material used for the liquid crystal layer is a vertical liquid crystal material having a negative Δε, the refractive index anisotropy Δn at room temperature is set to 0.07 or more, and the cell gap d, which is the thickness of the liquid crystal layer, is set to 4 μm or less. The

  Image quality evaluation and contrast evaluation were performed on the manufactured liquid crystal display element. The evaluation results are shown in Table 3.

The conditions for the examples and comparative examples are the same as in Table 1.
In this case, the light leakage was somewhat noticeable in Comparative Example <3>.

An inorganic alignment film is generally said to have weaker alignment control than polyimide because of its low anchoring energy.
In the evaluation results, the alignment disorder in the peripheral portion of the spacer was particularly severe, but a high-quality and high-quality liquid crystal panel could be obtained by employing the arrangement according to the embodiment of the present invention.

As described above, according to this embodiment, by devising the arrangement position (formation position) of the columnar spacers, it is possible to prevent image quality defects caused by light leakage of the spacers, and the characteristics such as contrast are good. In addition, a liquid crystal display element with good display performance can be realized.
That is, by optimizing the spacer layout design, it becomes difficult to visually recognize alignment abnormalities and the like occurring in the pixel. Further, by suppressing the occurrence of image quality defects, high quality image quality can be obtained.
As a result, a high-quality liquid crystal display element can be realized.
In addition, in a projection type LCD such as a projector, it is possible to increase the aperture ratio by reducing the panel size or expanding the effective pixel area, and it is possible to realize high productivity and high yield by cell gap control. Since materials such as inorganic materials can be applied without degrading the image quality, the life can be extended.

  The present invention can also be applied to a projection display system using a laser light source, and in this case, the same effect as that of this embodiment can be obtained.

It is a figure which shows a pixel although light incident ideally. It is a figure which shows the example which color mixing of color generate | occur | produces. It is a schematic block diagram which shows an example of the projection type display apparatus which employ | adopted the liquid crystal display element which concerns on embodiment of this invention. It is a figure which shows schematic structure containing the micro lens array of the liquid crystal display element of this embodiment. It is sectional drawing which shows schematic structure of the active matrix type liquid crystal display element which concerns on this embodiment. It is a figure which shows the example of arrangement | positioning in the array substrate (liquid crystal panel part) of the active matrix type liquid crystal display element which concerns on this embodiment. It is sectional drawing which shows the specific structural example of the active matrix type liquid crystal display element which concerns on this embodiment. It is a figure for demonstrating the structure of the pixel unit of this embodiment, and the arrangement position of a spacer. It is a figure which shows the relative luminous sensitivity of the photopic vision of a CIE photometry standard observer. It is a figure for demonstrating the suitable arrangement position with respect to the pixel electrode of the spacer of this embodiment. It is a figure which shows the relationship between a pixel electrode and a spacer used for the Example.

Explanation of symbols

  PRJ: projection display device, 1 ... liquid crystal display element, 2 ... light source unit, 3 ... condenser lens, 4R, 4G, 4B ... dichroic mirror, 5 ... projection lens (projection) Optical system), 11 ... TFT array substrate, 12 ... Counter substrate, 13 ... Liquid crystal layer, 14 ... Pixel electrode, 15 ... Counter electrode, 16 ... Sealing material, 46 ... -Spacer, 50 ... unit pixel, 51 ... first pixel (R), 52 ... second pixel (G), 53 ... third pixel (B).

Claims (12)

Two substrates facing each other;
A liquid crystal layer disposed between the two substrates;
A plurality of pixel electrodes disposed on opposing surfaces of each substrate to form matrix-like pixels;
An alignment film formed on the two substrates to align the liquid crystal of the liquid crystal layer in a predetermined direction;
A spacer formed between the pixel electrodes disposed adjacent to each other between the two substrates,
The pixel unit is a three-pixel unit of a first pixel, a second pixel, and a third pixel formed with red, green, and blue.
The spacer is
A liquid crystal display element formed between adjacent pixel units. The spacer is
The liquid crystal display element according to claim 1, wherein the liquid crystal display element is formed between at least the first pixel and the third pixel. The liquid crystal display element according to claim 2, wherein the second pixel is a green pixel. The spacer is disposed between the four adjacent pixel electrodes A1, A2, B1, and B2,
When the four pixel electrodes are defined as the front side A1, A2 and the self side B1, B2 with respect to the alignment direction,
The shortest distance (a) from the spacer center extension line to the pixel electrodes A1, A2 and the shortest distance (b) to the pixel electrodes B1, B2 satisfy a relationship of (a) ≦ (b). Liquid crystal display element. The liquid crystal display element according to claim 1, wherein the liquid crystal used in the liquid crystal layer has a refractive index anisotropy at room temperature of 0.10 or more and a thickness of the liquid crystal layer of 4 μm or less. The liquid crystal display element according to claim 1, wherein the liquid crystal panel provided with the pixel electrode is a transmissive type. The liquid crystal display element according to claim 1, wherein a pixel pitch of the single monochrome pixel is 20 μm or less. The liquid crystal display element according to claim 1, wherein the alignment film is formed of an inorganic alignment film. A light source;
A liquid crystal display element;
A condensing optical system that separates light emitted from the light source into colored light of red light, green light, and blue light having different principal wavelengths, and guides the light to the liquid crystal display element;
A projection optical system for enlarging and projecting light modulated by the liquid crystal display element,
The liquid crystal display element is
Two substrates facing each other;
A liquid crystal layer disposed between the two substrates;
A plurality of pixel electrodes disposed on opposing surfaces of each substrate to form matrix-like pixels;
An alignment film formed on the two substrates to align the liquid crystal of the liquid crystal layer in a predetermined direction;
A spacer formed between the pixel electrodes disposed adjacent to each other between the two substrates,
The pixel unit is a three-pixel unit of a first pixel, a second pixel, and a third pixel formed with red, green, and blue.
The spacer is
A projection type liquid crystal display device formed between adjacent pixel units. The spacer is
The projection type liquid crystal display device according to claim 9, wherein the projection type liquid crystal display device is formed between at least the first pixel and the third pixel. The projection type liquid crystal display device according to claim 10, wherein the second pixel is a green pixel. The spacer is disposed between the four adjacent pixel electrodes A1, A2, B1, and B2,
When the four pixel electrodes are defined as the front side A1, A2 and the self side B1, B2 with respect to the alignment direction,
The shortest distance (a) from the spacer center extension line to the pixel electrodes A1 and A2 and the shortest distance (b) to the pixel electrodes B1 and B2 satisfy a relationship of (a) ≦ (b). Projection type liquid crystal display device.

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