JP3241118B2 - Liquid crystal display element and liquid crystal display device using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal is related to a liquid crystal display device using a liquid crystal display element and it is formed by sandwiching a liquid crystal and solidified matrix composite, which is dispersed and held in a solidified matrix.

[0002]

2. Description of the Related Art In recent years, liquid crystal displays have taken advantage of their features such as low power consumption and low voltage driving, and have been used in personal word processors, hand-held computers, pocket TVs, and the like.
V is widely used. Among them, a liquid crystal display element in which an active element is arranged for each pixel electrode has attracted attention and is being actively developed.

[0003] Such a liquid crystal display element was initially known as DSM.
A liquid crystal display device using a (dynamic scattering) type liquid crystal has also been proposed. However, the DSM type has a drawback that the current flowing through the liquid crystal is high, so that the current consumption is large.
A liquid crystal using (twisted nematic) type liquid crystal has become mainstream, and has appeared on the market as a pocket TV.
The TN-type liquid crystal has a very small leakage current and low power consumption, and thus is suitable for an application using a battery as a power supply.

[0004] In the liquid crystal display device using the TN liquid crystal, because it requires two polarizing plates, a problem that the transmittance of light is small there Ru. In particular, when performing color display using a color filter, only a few% of the incident light can be used, and a strong light source is required, which results in an increase in power consumption.

For this reason, a transmission-scattering characteristic according to an input voltage (electric field generated between electrodes) is obtained by using a liquid crystal solidified composite in which a nematic liquid crystal is dispersed and held in a solidified matrix such as a resin matrix. There has been proposed a mode that can be driven at a low voltage of 10 V or less using the above. Since the liquid crystal solidified composite has a function of transmitting and scattering light without using a polarizing plate, it is expected that a bright display can be obtained in the case of transmission.

[0006]

However, the conventional liquid crystal display is
In a liquid crystal display device using a compound
Hysteresis exists in the voltage-transmittance characteristics.Sand
That is, when the applied voltage is stepped up and stepped down, the light transmittance is
Are differentHave a problemChanges in the display screen
Burn-in phenomenon that information on the previous screen sometimes remains
(Afterimage of seconds or more) and transmittance is not
Images such as reduced gradation due to unintentional decisions
The problem that the quality may deteriorateThereWas.

Further, the applied voltage-transmittance characteristics of the solidified liquid crystal composite generally have stronger nonlinearity than the conventional TN type liquid crystal display element. It is necessary to modulate the voltage applied according to the characteristics, that is, the input signal voltage, that is, to perform γ (gamma) correction with strong nonlinearity.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an electrode A is provided on a substrate A.
And the electrodes B are provided on the substrate B, the substrates A and B are arranged so that the electrodes A and B face each other, and the liquid crystal is dispersed and held in the solidified matrix between these electrodes. In the liquid crystal display element sandwiching the liquid crystal solidified composite, the substrate A and the electrode A are transparent, the surface of the electrode A on the liquid crystal solidified composite side has a fine uneven surface, and light is emitted to the electrode B or the substrate B. with the reflecting surface is provided with a reflecting material, the surface of the liquid crystal and solidified matrix composite side electrode B is flat, the center line average roughness R _a of the uneven surface of the electrode a, the average inter-electrode gap Provided is a liquid crystal display device characterized by satisfying a relationship of 0.03 · G < _Ra <0.3 · G, where G is the pitch of the uneven surface of the electrode A is 4 μm or more. Ma
In this liquid crystal display device, the substrate A has a fine uneven surface.
Is provided, and the uneven surface derived from the uneven surface of the substrate A is the electrode A
The present invention provides a liquid crystal display element formed on the substrate. Further, the electrode A is provided on the substrate A, the electrode B is provided on the substrate B, and the substrates A and B are arranged so that the electrode A and the electrode B face each other. In a transmission-scattering type liquid crystal display device sandwiching a liquid crystal solidified composite dispersed and held in a matrix, a substrate A and an electrode A are transparent, and the surface of the electrode A on the liquid crystal solidified composite side has a fine uneven surface. A reflective surface is provided on the electrode B or the substrate B using a material that reflects light, the surface of the electrode B on the side of the liquid crystal solidified composite is flat, and the substrate A has a fine uneven surface.
The uneven surface derived from the uneven surface of the substrate A is formed on the electrode A.
A liquid crystal display device is provided, wherein an outer surface of the substrate A is coated with an antireflection coating by a multilayer interference film.

Further , any one of the above-mentioned liquid crystal display elements has
And a liquid crystal display device in which active elements are arranged on a substrate B.

[0010] Also, either of the liquid crystal display device of the result from the driving circuit, the liquid crystal display device and displaying the halftone by applying a voltage of the saturation voltage following values by the drive circuit provide.

[0011] In the liquid crystal display device of the present invention, the electrode A is provided on the substrate A, electrode B is provided on the substrate B, and the electrode A
The substrate A is transparent, and the electrode B or the substrate B is a reflection surface (hereinafter referred to as a reflection surface ).
Below, it is also called a reflective layer. ) Is a, a material containing a liquid crystal which is further sandwiched between electrodes, and a liquid crystal and solidified matrix composite capable of controlling a transparent state electrically scattering state directly.

This structure eliminates the need for a polarizing plate, and can greatly improve the transmittance when transmitting light. For this reason, a bright display can be achieved, and particularly when used for a projection type display, a bright, high-contrast projection type display can be obtained .

In the present invention , a pair of electrodes and a substrate on one side are made transparent, and a reflection surface is provided on the other side. The reflection surface could be achieved by making the electrode itself reflective, or by making the electrode transparent and making the surface of the substrate reflective. Alternatively, it was possible to provide a reflective film on the substrate surface. Further, when the liquid crystal display element of the present invention is used as a color display element, it becomes possible by forming a color filter having a function of wavelength selective absorption or wavelength selective reflection on the substrate A or the substrate B.

Further, the liquid crystal and solidified matrix composite used in the liquid crystal display device of the present invention, the transmission - if even in a mode other than the scattering type liquid crystal of the liquid crystal and solidified Toka et consisting distributed, the present invention Ru can be obtained the effect of the hysteresis image burn-in due to suppression, the largest effect. Specifically, the present invention was also applicable to a transmission-absorption type liquid crystal display device comprising a guest-host type liquid crystal in which a dichroic dye was dissolved in a liquid crystal and a solidified material.

In the present invention, it is a hand electrode of the electrodes sandwiching the liquid crystal and solidified matrix composite had fine surface roughness on the surface of the liquid crystal and solidified matrix composite body side structure, the gap of the counter electrode is distributed minutely As a result, the image sticking phenomenon on the liquid crystal display screen due to the hysteresis inherent to the solidified liquid crystal composite was suppressed. As a result, beautiful display is possible even when performing halftone display. In particular, when the liquid crystal solidified composite is directly in contact with the surface of the electrode to form an uneven surface at the interface with the electrode, and when used as a reflective liquid crystal display device, the uneven surface can suppress regular reflection, and display Another advantage is that the contrast ratio is improved.

The liquid crystal display device of the present invention could be used for both a direct-view display device and a projection display device. When used as a direct-view display element, a display device may be configured by combining a backlight, a lens, a prism, a mirror, a diffuser, a light absorber, a color filter, and the like in accordance with desired display characteristics.

It is necessary to reduce the hysteresis in the applied voltage-transmittance characteristic of the solidified liquid crystal composite to improve the display quality.
Liquid crystal material, a polymer material forming a solidified product by hardening using
This was possible by optimizing the material of the material and the structure of the liquid crystal solidified composite. However, this required strict control techniques. In the present invention, even if there is some hysteresis, but this is not the actual display on the problem, (also, the optical problems caused by hysteresis) the apparent hysteresis could be reduced. Therefore, the present invention, the material selection width and advantages spread of the use, Ru advantages there of such as taken large margin in manufacture.

[0018] Therefore, the electrode surface of the hand in the present invention is a fine uneven surface in the liquid crystal and solidified matrix composite body side. As a result, a desirable distribution of the inter-electrode gap was obtained, and an electric field across the liquid crystal solidified composite was distributed. As a result, the threshold voltage of the applied voltage-transmission characteristic was dispersed. sand
Chi it, even in the case of using a liquid crystal and solidified matrix composite in the presence of hysteresis, in accordance with the distribution of the inter-electrode gap for the distribution of the electric field across the liquid crystal and solidified matrix composite, the threshold is dispersed,
The electro-optical characteristics were displayed as the average values of the inter-electrode gaps at various positions on the uneven surface described above, and apparent hysteresis was reduced.

FIG. 1 is a sectional view of a liquid crystal display device of the present invention. In FIG. 1, 1 is a liquid crystal display element, 2 is glass,
Substrate having irregularities such as plastic is ITO (In)
₂ O ₃ —SnO ₂ ), electrodes such as SnO ₂ , 4 is glass,
The other flat substrate such as plastic is made of ITO (In
Electrodes of ₂ O ₃ —SnO ₂ ), SnO ₂ , Al, Cr, etc.
Reference numeral 6 denotes a solidified liquid crystal composite such as a liquid crystal resin composite sandwiched between both substrates (between electrodes). Here, a case where ITO and SnO ₂ are used as the electrode 3 is a transparent electrode, and A
The case of using l and Cr is a non-transparent electrode. The metal electrode generally has the ability to reflect light and can be used as a reflecting surface.

In the present invention has an uneven electrode surface board A side. The substrate A itself may have an uneven surface like the electrode. In the example of FIG. 1, only the substrate A on the left side has an uneven electrode surface,
And a substrate having an uneven surface . Uneven surface of this is normal,
The substrate was formed by spraying fine particles, processing by polishing, etching and the like, and then attaching electrodes.

An insulating layer, a layer for compensating and flattening the uneven electrode surface, a color filter, or a layer provided for another purpose adheres to the electrode surface having the uneven surface corresponding to the substrate surface. Could be formed. Basically, since the inter-electrode gap may be changed, or with a concave convex electrode to flatten the substrate. Even if minute <br/> distribution compared to the inter-electrode gap could be a constant thickness of the liquid crystal and solidified matrix composite by forming a flattening layer to compensate it to the uneven surface of the electrode. For example, it is preferable to use a liquid crystal solidified composite film.

[0022] In the present invention, one side of the substrate, or electrode is the reflective electrode gold <br/> genus, light a reflective surface in combination with the transparent electrode and the reflective film is in so that the reflected Just do it. Further, in each pixel, if necessary, TFT (thin film transistor), a thin film diode, may also be disposed an active element of the MIM or the like, the pixel electrodes have been the transparent electrode
Alternatively, the wiring of the active element on the substrate may be an opaque electrode made of metal, or a photoconductor layer such as a photoconductive material for optical writing may be laminated.

When arranging the active elements, they are usually arranged on the flat substrate side. Also, instead of applying a voltage to each pixel electrode by an active element, a light beam such as a laser beam is applied to a display element having a photoreceptor layer.
Or it may be supplied corresponding charges by direct electron gun to the pixel position.

In the case of a reflective liquid crystal display device, the effective optical path length of the solidified liquid crystal composite is twice that of a transmissive liquid crystal display device. Therefore, in the light scattering state, the scattering power of the reflection type liquid crystal display element is considerably larger than that of the transmission type liquid crystal display element. As a result, the performance of a display device including a reflective display element is improved as compared with a display device using a transmissive display element. For example, low voltage driving, high contrast ratio, wide viewing angle display, or the Koteru degree Display achieve
Can Ru.

[0025] When used in a reflection type, the regular reflection of light at the substrate outer surface and an inner surface of the front side (the side where light is incident emitted) becomes a cause of lowering the contrast ratio. Therefore, by using the substrate having the uneven electrode surface on the front side,
Regular reflection at the interface of the substrate having the uneven electrodes can be reduced. Chi words, by using a substrate having an uneven electrode surface, it was possible to obtain both effect of hysteresis improvement and glare suppression (improved contrast ratio by it) at the same time.

In particular, when used as a projection type liquid crystal display device, an aperture as a device for reducing diffused light, which will be described later, is used. Therefore, the reflected light due to scattering at the substrate interface with an uneven electrode surface, since all etc. photons do not pass through the aperture becomes diffused light, utilization of improving the contrast ratio of the projected image
Points are big. In this case, the shape of the concavities and convexities formed by the inclined surfaces having an appropriate inclination angle is more effective in removing scattering at the substrate interface than the rectangular irregularities having many flat surfaces. This angle of inclination is preferably about 2 to 30 ° with respect to the reflection surface.

The use of a reflection type liquid crystal display element in a projection type display device improves the scattering power of the display device. Therefore ,
The directivity (parallelism) of light incident on the display device required to obtain the same projection image contrast ratio is reduced. As a result, when a lamp other than a point light source was used, the light collection efficiency of the light source optical system was improved, and a high-brightness projected image could be realized, compared to the case of a projection display device including a transmissive liquid crystal display element. .

The previously mentioned, transmission of a liquid crystal and solidified matrix composite - in the case of the absorption-type liquid crystal display device of the advantage of reducing the hysteresis, and both of <br/> advantage of forming a diffuse reflective surface By using the concave and convex surface of the substrate having the concave and convex electrode surface as the reflection surface, it can be obtained at the same time.

In the present invention, in order for the electro-optical characteristics to be averaged and observed by an observer, the pitch of the unevenness of the substrate having the uneven electrode surface needs to be finer than the display pixel size. For example, in the case of a projection type active matrix display element, since the pixel size is relatively small and the size of a normal pixel is about 30 μm to 200 μm, it is necessary to use an uneven pitch smaller than this pixel size. Becomes Usually, in the case of a projection type active matrix display element, the pitch is preferably 100 μm or less.

If the pitch is too small, the effect of averaging the electro-optical characteristics is reduced, and the reduction in image burn-in due to hysteresis cannot be expected. In the case of a liquid crystal solidified composite, the effect of averaging the electro-optical characteristics can be obtained.
The minimum scale is determined by the size of the liquid crystal particles dispersed and held in the solidified matrix.

The transmissive liquid crystal display device of the present invention - scattering properties, the liquid crystal molecular alignment in the liquid crystal particles is changed by the applied electric field, thereby had accompanied to vary the apparent liquid crystal refractive index with respect to incident light liquid It is obtained by changing the refractive index difference at the interface between the particles and the solidified material . Therefore , in order to obtain the effect of reducing image sticking, it is necessary that the pitch of the irregularities is at least larger than the diameter of the liquid crystal particles.

Further, in the structure of the liquid crystal solidified composite having a high scattering property at the time of scattering, considering that the scattering cross section is several times (about 3 to 5 times) the cross sectional area of the particles, the reduction of image sticking is considered . The effect is strongly exhibited when the pitch P of the unevenness is twice or more the diameter of the liquid crystal particles. The Te but Tsu <br/>, pitch P of the irregularities with respect to the average particle diameter R _LC of liquid crystal is preferably a 2 · R _LC ≦ P.

In a liquid crystal solidified composite which can be driven at a low voltage, the _RLC is generally about 2 μm. In this case, the preferable pitch P is about 4 μm or more. Under such conditions, high transmittance is maintained because unnecessary scattering that occurs at the interface between the unevenness and the liquid crystal solidified composite and significantly reduces the transparency during transmission of the element hardly occurs. advantages Ru Oh.

It should be noted that the pitch P here does not necessarily mean that the irregularities indicate the periodic structure, and the “unit length” is replaced by “the number of peaks of the cross-sectional curve existing in the unit length”.
(Note that “the number of peaks in the section curve” is based on JIS B0601-1.
982).

In order to exhibit the effect of reducing the hysteresis, it is important how much the thickness of the solidified liquid crystal composite is distributed. If the depth d of the concavities and convexities of the substrate having the concavo-convex electrode surface is too small with respect to the average thickness (average interelectrode gap G), the effect of dispersing the voltage threshold does not appear, and the effect of reducing the hysteresis. Can not expect too. Conversely, d
It is too large, partially or Nari will be thin in thickness portion exist, to provoked a reduction in contrast.

The depth d of the unevenness is simple if the unevenness is uniform, but usually has a distribution. In the present invention, this is defined as the center of the unevenness surface as defined in JIS B0601-1982. center line average roughness R _a as irregularities displaced from a line Expressed by In this case, in order to efficiently obtain the effect of reducing the hysteresis, _Ra and G have an optimum range as shown in the following equation (1). 0.03 · G < _Ra <0.3 · G (1)

Therefore, the average gap G between the electrodes is 10 μm.
For m, the centerline average roughness R _a representing the state of the irregularities is set to 0.3 to 3 m. Ie, it becomes to have a correspondingly distribution according interelectrode gap surface roughness as a result.

[0038] In the present invention, Ri by the fact that in this way,
It applied voltage - to improve the linearity of the transmittance characteristics, Ru gradation display superior without using a special γ correction is obtained. This also you caused by electro-optical characteristics are averaged.

FIG. 2 is a schematic view of a reflection type projection type liquid crystal display device using the liquid crystal display element of FIG. In this reflection type liquid crystal display device, the reflection layer and the electrodes are formed on a flat surface of the substrate. In FIG. 2, reference numeral 11 denotes a light source for projection,
Reference numeral 12 denotes a reflection type liquid crystal display element, 13 denotes a lens, and 14 denotes a stop as a device for reducing diffused light, and projects an image on a projection screen (not shown) on the left side of the drawing.

In the apparatus shown in FIG. 2, light emitted from a projection light source 11 composed of a lamp, a reflector, a lens and the like provided on the left side of the liquid crystal display element enters a liquid crystal display element 12 via a lens 13. The incident light is applied to the liquid crystal display element 12.
The light is reflected by the reflection layer on the back side (right side) and exits to the left side, and is again stopped down via the lens 13. The diffused light is reduced by the stop 14 and only the light passing through the stop 14 is projected on the projection screen. .

As the projection light source , a known projection light source can be used. Lamps such as metal halide lamps, halogen lamps, xenon lamps, etc., mirrors such as spherical mirrors for condensing, elliptical mirrors, lenses, and parallel light beams are used. May be used in combination as needed. Further, the laser beam may be converted into a parallel beam using a beam expander or the like. In order to make this color, for example, the lens 13
And also between the liquid crystal display element 12 lens 13 and the aperture 14
The dichroic prism or by placing a dichroic mirror may be arranged three liquid crystal display device of this three sides between.

As the projection optical system, in FIG.
And an aperture 14. This may be any device as long as it can project the straight light emitted from the liquid crystal display element onto the projection screen. The projection lens may be the lens 13 alone,
An additional lens may be provided between the lens 13 and the aperture 14 or between the aperture 14 and the screen. In order to improve the image quality of the projected image, the lens before and after the aperture 14 13
In addition, it is preferable to provide a projection lens.

The device for reducing the diffused light may be any device that can pass only the straight light out of the light emitted from the liquid crystal display element and remove the diffused light. Apertures are typically used. Also,
A small reflecting mirror may be arranged in place of the hole to take out only the necessary straight light. Here, the operation state of the projection type liquid crystal display device of FIG. 2 will be briefly described. The liquid crystal display element has a transparent state, a scattering state, and an intermediate state for each pixel depending on the magnitude of the applied voltage.

[0044] In the portion of the transparent state, emitting the incident side light incident from the substrate of the front usually shines anti intact reflective layer provided on the flat surface of the substrate located on the back side of the display elements of the display device I do. This light passes through the stop 14 because the optical axis is the same as the regular reflection. This results in a bright spot on the projection screen. On the other hand, in the part in the scattering state, the incident light is scattered and emitted to the incident side after being reflected directly or as a diffused light by the reflection layer. Since most of the light is the optical axis is different from the regular reflection, it can not pass through the aperture 14.

This results in a dark dark spot on the projection screen. The part in the intermediate state is in the middle, and a part of the incident light passes through the stop 14. This results in a halftone on the projection screen. At this time, the liquid crystal display device shown in FIG.
When a liquid crystal display device as shown in, in together when the burn of the image based on the hysteresis can be suppressed, it is possible to display a high contrast ratio. In this case, reflection of incident light on the outer surface of the substrate of the liquid crystal display element (the left side of the left substrate in FIG. 1) also lowers the contrast ratio. It is preferable to suppress glare by using

According to the present invention, image sticking based on hysteresis can be suppressed even when a transmission type is used instead of a reflection type.
You. In this case, a projection light source may be provided on the left side of FIG. 2, a projection optical system may be provided on the right side, and light may be incident on the liquid crystal display element from the left side and emitted on the right side.

[0047] In the present invention, between the substrate with electrode is a substrate other hand has an uneven electrode surface, the liquid crystal is sandwiched a liquid crystal and solidified matrix composite, which is dispersed and held in a solidified matrix. The liquid crystal and solidified matrix composite is fine Rukoto such a large number formed solidified matrix and has been a nematic liquid crystal filled in the portion of the hole of the hole is preferred. In this case, the liquid crystal solidified composite takes a transmission state and a scattering state by applying a voltage between the electrodes sandwiching the composite. Chi words, the magnitude of the applied voltage, the refractive index of the liquid crystal apparent changes with respect to the incident light, the solidified matrix relationship between the refractive index of the liquid crystal refractive index changes of both refractive index of When they match, they are in a transmission state, and when they have different refractive indices, they are in a scattering state.

The liquid crystal solidified composite composed of the resin matrix having a large number of fine pores and the liquid crystal filled in the pores has a structure in which the liquid crystal is sealed in a liquid bubble such as a microcapsule. However, the individual microcapsules do not need to be completely independent, and liquid bubbles of individual liquid crystals may be communicated via the slits like a porous body.

In order to obtain a solidified liquid crystal composite used in the liquid crystal display device of the present invention, a nematic liquid crystal and a curable compound constituting a solidified matrix are mixed to form a solution.
Or leave this latex form, which light-curing, thermal curing, curing by solvent removal, by reaction curing, etc. to separate the nematic liquid crystal and cured product, to take a state in which the nematic liquid crystal is dispersed in solidified matrix What should I do?

[0050] The curable compound, by photocuring or to thermosetting type, preferred because it can cure in a closed system. In particular, the use of a photocurable curable compound is preferable because it can be cured in a short time without being affected by heat.

As a specific production method, a cell is formed using a sealing material in the same manner as a conventional ordinary nematic liquid crystal, and an uncured mixture of the nematic liquid crystal and the curable compound is injected from an injection port. After sealing, it can be cured by irradiating light or heating.

In the case of the liquid crystal display device of the present invention,
Without using a sealing material, for example, an uncured mixture of a nematic liquid crystal and a curable compound is supplied onto one substrate with an electrode, and then the other substrate with an electrode is overlaid and cured by light irradiation or the like. It can also be done.

Of course, after that, a sealing material may be applied to the periphery to seal the periphery. According to this production method, the uncured mixture of the nematic liquid crystal and the curable compound may be simply supplied by roll coating, spin coating, printing, coating with a dispenser, or the like, so that the injection step is simple and the productivity is low. Very good.

Further, the uncured mixture of the nematic liquid crystal and the curable compound includes ceramic particles for controlling the gap between substrates, plastic particles, spacers such as glass fibers, pigments, dyes, viscosity modifiers, and the like. You may add the additive which does not have a bad influence on the performance of this.

[0055] the element is a scattering state when no voltage is applied, by curing while applying a charging voltage higher only in certain parts during the curing process, be always light transmission state that part If there is something to be fixedly displayed, such a normally transparent portion may be formed. Conversely, in the case of an element that is in a transmission state when no voltage is applied, an ordinary scattering portion can be formed in a similar manner.

The specific resistance of the solidified liquid crystal composite is 5 ×
Those having a resistivity of 10 ⁹ Ω · cm or more are preferable. Furthermore, in order to minimize the voltage drop due to leakage current or the like, 10 ¹⁰ Omega ·
cm or more is preferable, and power consumption is small. In particular, when an active element is used for each pixel, it is not necessary to provide a large storage capacitance for each pixel electrode.

The transmittance of the liquid crystal display device using the solidified liquid crystal composite in the transparent state is preferably as high as possible, and the haze value in the scattering state is preferably 80% or more.

[0058] In the present invention, also a voltage applied state in either the non-application state, the refractive index of the solidified matrix (after curing) is consistent with the refractive index of the liquid crystal used, solidified matrix is the inverse of the state Is preferably set not to match the refractive index of the liquid crystal used .

As a result, light is transmitted when the refractive index of the solidified matrix and the refractive index of the liquid crystal match, and the light is scattered (white turbid) when they do not match. The scattering power of this device is higher than that of a conventional DSM type liquid crystal display device, and a display with a high contrast ratio can be obtained.

[0060] In the present invention, particularly, in a state in which voltage is applied, solidified product Matrix scan refractive index of after curing, of liquid crystal used ordinary refractive index n _o Preferably, it is made to coincide with: Thereby, since a transparent state is obtained when a voltage is applied, the transmittance in the transparent state where light is transmitted is high and the light is transmitted uniformly, so that the display contrast ratio is improved.

[0061] The liquid crystal used refractive index anisotropy Δn (= n _e
-N _o, where, n _o is the ordinary refractive index, n _e is the extraordinary refractive
rate. ) Contributes to the scattering power at the time of no voltage, and is preferably larger than a certain level in order to obtain high scattering properties, specifically, Δn> 0.18, and particularly Δn> 0.2.
2 is preferred. Further, the ordinary refractive index n _o of the liquid crystal used is preferably substantially matches the refractive index n _p of the solidified matrix, high transparency when a voltage applied at this time can be obtained.
Specifically, it is preferable to satisfy the relationship of _{n o -0.03 <n p <n} o +0.05.

In order to improve the scattering ability under no voltage, it is effective to increase the volume fraction Φ of the operable liquid crystal of the solidified liquid crystal composite, and Φ> 20% is preferable.
For higher scattering power, Φ> 35% is preferable, and Φ> 45% is more preferable. On the other hand, if Φ is too large, the structural stability of the solidified liquid crystal composite deteriorates.
Φ <70% is preferred.

[0063] In the liquid crystal display device of the present invention, the refractive index of the solidified matrix, a liquid crystal used ordinary refractive index n _o When a voltage is not applied, a liquid crystal display element that is not aligned in a certain direction and a liquid crystal that is not aligned in a certain direction, due to a difference in the refractive index of a solidified matrix, is in a scattering state (that is, white turbidity). State).

When such a liquid crystal display device is used as a projection type display device, light is scattered in portions without electrodes and light reaches the projection screen without providing a light-shielding film in portions other than the pixel electrodes. Does not look black. Thus, in order to prevent leakage of light from portions other than the pixel electrodes, necessary to shield the portions other than the pixel electrode in the light-shielding film or the like is rather name advantage that step of forming the light shielding film is not necessary
Oh Ru.

A voltage is applied to a desired pixel of the liquid crystal display device. The applied pixel portion of this voltage, the liquid crystal is aligned, the liquid crystal of the ordinary refractive index n _o And the refractive index of the solid matrix
n _p When this matches, the transmission state is indicated, and light is transmitted through the desired pixel, and the image is displayed brightly on the projection screen.

In the present invention, when a photocurable compound is used as the uncured curable compound constituting the liquid crystal solidified composite, the use of a photocurable vinyl compound is preferred.
Specifically, a photocurable acrylic compound is exemplified, and a compound containing an acrylic oligomer which is polymerized and cured by light irradiation is particularly preferable.

[0067] The liquid crystal used in the present invention is a nematic liquid crystal having a positive dielectric anisotropy, the refractive index of the solidified matrix and the refractive index of the liquid crystal is also when the voltage is applied in either the time of non-application It is preferable that the liquid crystal matches the
Good. Liquid crystals, it may also be also used compositions used alone Iga, operating temperature range, to meet the various performance requirements such as operating voltage can be said that advantageous using composition. In particular, the refractive index of the solidified matrix, liquid crystal ordinary refractive index n _o It is preferable to use a liquid crystal that matches the formula.

[0068] liquid crystal used in the crystal and solidified matrix composite, when using a photo-curable compound, it is preferable to dissolve the photocurable compound uniformly, not cured after light exposure is dissolved also Is difficult to dissolve, and when a composition is used, it is desirable that the individual liquid crystals have solubility as close as possible.

In the present invention, the liquid crystal is used as a solvent as the liquid crystal solidified composite, and the photocurable compound is cured by light exposure, so that it is not necessary to evaporate a mere solvent or water which is unnecessary at the time of curing. For this reason, since it can be cured in a closed system, the conventional manufacturing method of injection into a cell can be employed as it is, and it has high reliability and also has an effect of bonding two substrates with a photocurable compound, so that more reliability can be obtained. The nature becomes high.

In the present invention, as described above, at least one of the substrates is a substrate having an uneven electrode. However, since it is a liquid crystal solidified composite, there is little danger of a short circuit even in a narrow gap. Further, unlike the ordinary TN type display element, it is not necessary to strictly control the orientation and the gap between the substrates, and a liquid crystal display element capable of controlling the transmission state and the scattering state can be manufactured with extremely high productivity.

[0071] In the case of using the T FT as the active element, the semiconductor material silicon is preferred. In particular, polycrystalline silicon does not have high photosensitivity like amorphous silicon, and thus does not easily malfunction even if light from a light source is not blocked by a light-blocking film, which is preferable. This polycrystalline silicon
When used as a projection type liquid crystal display device as in the present invention,
A strong light source for projection can be used, and a bright display can be obtained.

[0072] In the present invention, the liquid crystal of the ordinary refractive index n _o of the refractive index of the solidified matrix to <br/> used By using the liquid crystal solidified composite that is made to substantially match with the above, light is scattered in a portion where no voltage is applied in the projection display device, and the light is blackened on the projected projection screen, so that light is blocked between pixels. It is not necessary to form a film. Therefore, when using polycrystalline silicon as the active element, since it is weak in its shielding property or if it is not necessary to form the light shielding film to the active element portion, or eliminating the step of forming the light shielding film, The strictness of the formed light shielding film can be relaxed, and the productivity is improved.

The liquid crystal display device and the liquid crystal display device of the present invention may further include an infrared cut filter, an ultraviolet cut filter, a color filter, a cooling system, a reinforcing glass plate, and the like. Characters, figures, and the like may be printed, or a plurality of liquid crystal display elements may be used. In addition, light from a light source may be dispersed using a dichroic mirror, a dichroic prism, or a mirror to combine colors, or light emitted from a liquid crystal display element may be combined.

[0074]

According to the present invention has a fine uneven electrode surface electrode substrate with hand is in terms of the liquid crystal and solidified matrix composite body side. For this reason,
Dispersion of the interelectrode gap occurs and an electric field across the solidified liquid crystal composite is distributed. As a result, the voltage threshold of the solidified liquid crystal composite is dispersed. Thereby, the image sticking phenomenon due to the hysteresis inherent to the solidified liquid crystal composite can be suppressed. This only requires control of the unevenness of the substrate, and the tolerance is wide, so that the productivity is good. This allows
Ru can be beautiful display even in the half-tone display.

[0075] By providing the irregular surface of this substrate on the incident side, there is the effect of suppressing glare. That is, there is an advantage that regular reflection can be suppressed and the display contrast ratio is improved.

[0076]

EXAMPLES In the following Reference Examples 1 to 3 , since the substrate with electrodes has fine electrode surfaces on the liquid crystal solidified composite side,
Toru the burn-in phenomenon of the image due to hysteresis was suppressed
This is an example of overmolding. Comparative Examples 1 to 4 are examples in which the image sticking phenomenon due to hysteresis is not sufficiently suppressed because the substrate with electrodes does not have an appropriate uneven electrode surface on the liquid crystal solidified material composite side. Reference Example 1 A solution was prepared in which a nematic liquid crystal having a positive dielectric anisotropy, an acrylate monomer, a urethane acrylate oligomer, and a photoreaction initiator were uniformly dissolved. A cell was formed using a TFT substrate on which a TFT was provided for each pixel electrode on a flat surface, a counter electrode substrate provided with a transparent counter electrode, and a spacer having a diameter of 10 μm. After injecting the previously prepared solution into the cell, it was cured by exposure to ultraviolet light to obtain a liquid crystal resin composite. The average liquid crystal particle diameter _RLC was about 2 μm.

The pixel size was about 200 μm × 200 μm. The portion of the opposing electrode substrate that was in contact with the liquid crystal resin composite was subjected to unevenness processing, the unevenness pitch was 50 μm, the depth of the unevenness was about 4 μm, and _Ra was about 1 μm. ITO was deposited on the irregularities to form a counter electrode. The average inter-electrode gap of the cell was about 12 μm.

The driving voltage of this liquid crystal display element was about 7 V (volt), and a display with almost no image sticking was obtained. The transmission type liquid crystal display element and the projection light source for, was the projection morphism type display device using a projection optical system, the contrast ratio on the projection screen is obtained moving image display 120. When the voltage transmittance characteristics of this device were measured,
The transmittance at 7 V was 70%. The hysteresis was very small, and the maximum difference between the transmittance at the time of boosting and the transmittance at the time of step-down was 2.8% in the process of increasing the voltage from 0 V to 10 V and then decreasing the voltage to 0 V.

(Comparative Example 1) A cell was formed in substantially the same manner as in Reference Example 1 so that the opposing substrate was a flat substrate on which ITO was deposited and the average interelectrode gap was 12 μm. The same liquid crystal resin composite as in Reference Example 1 was prepared and used as a display cell. Although the driving voltage of this element was about 7 V, the display was burned on a specific screen.

As in Reference Example 1, when the projection type display device was used, the contrast ratio was about 130 on the projection screen.
Met. When the voltage transmittance characteristics of this device were measured, the transmittance at 7 V was 71%, and the maximum difference in transmittance due to hysteresis was 5.0%.

( Reference Examples 2 and 3, Comparative Examples 2 and 3) Display elements were prepared in substantially the same manner as in Reference Example 1. However,
Table 1 shows the average interelectrode gap G (μm), the pitch P (μm) and the roughness _Ra (μm) of the unevenness of the substrate having unevenness. The contrast ratio CR on the projection screen when the projection type display device is used, and the transmittance T at 7 V
_7V (%), maximum value ΔT of difference in transmittance due to hysteresis
(%) Is shown in the table.

[0082]

[Table 1]

(Example 1 ) A liquid crystal display device was constructed in substantially the same manner as in Reference Example 1, and a projection type liquid crystal display device was obtained by combining with a projection light source and a projection optical system. However, the electrode of the TFT substrate was an aluminum electrode and used as a reflective element, and the outer surface of the counter electrode substrate was coated with an anti-reflection coating by a multilayer interference film. The average interelectrode gap is about 10 μm, and the pitch P of the irregularities is about 9 μm.
m, the depth of the unevenness was about 1.3 μm, and _Ra was about 0.4 μm. The driving voltage of this element was about 6 V. When driven by a video signal, a moving image display without burn-in was obtained. The contrast ratio on the screen was 110.

Comparative Example 4 As in Example 1, the pitch P was 3 μm and _Ra was 0.5.
μm. As a result, the contrast ratio was 90, _T7v was 65%, and ΔT was 4.8%. The transmittance and the contrast ratio were slightly reduced, but there was almost no effect of reducing the hysteresis.

[0085]

The liquid crystal display element of the present invention uses a liquid crystal solidified composite such as a liquid crystal resin composite, and the electric field across the liquid crystal solidified composite is distributed according to the dispersion of the gap between the electrodes. , The threshold voltage is dispersed, and the hysteresis in the transmittance-voltage characteristics of the solidified liquid crystal composite is apparently low.
It came under reduced. As a result, the gas-image burn-in at the low reduction, made it possible to display good reproducibility of halftone. Further, the applied voltage - to improve the linearity of the transmittance characteristics, gradation display superior without using a special γ correction is obtained.

Eight gradations generally required for a display element
To 16 tone about performance, it could be achieved in the charge amount. Further, depending on various parameters of the liquid crystal display element and required functions, more than 30 gradations can be achieved.

Further, the solidified liquid crystal composite and the electrode forming the uneven surface are in direct contact with each other to form an uneven interface, and the interface having the uneven structure is inclined with respect to the average plane of the substrate surface. Due to having, regular reflection could be removed. In particular, by using the liquid crystal display element of the present invention as a projection display device, it was possible to prevent a decrease in contrast ratio due to reflected light.

[0088] Further, the reflection-type projection display apparatus odor
As a result , the decrease in contrast ratio due to regular reflection at the interface between the transparent electrode and the solidified liquid crystal composite was significantly improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a liquid crystal display device of the present invention.

FIG. 2 is a schematic view of a reflective projection type liquid crystal display device using the liquid crystal display element of the present invention.

[Explanation of symbols]

 1, 12: liquid crystal display element 2: substrate with unevenness 3, 5: electrode 4: substrate 6: liquid crystal solidified composite

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tsuneo Wakabayashi 1160 Matsubara, Hazawa-machi, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture A-G Technology Co., Ltd. In-house examiner Hideo Kawahara (56) References JP-A-5-203943 (JP) , A) JP-A-3-23422 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1334 G02F 1/1333 G02F 1/1335

Claims (5)

(57) [Claims] An electrode A is provided on a substrate A, an electrode B is provided on a substrate B, and a substrate A and a substrate B are arranged such that the electrodes A and B face each other. In a liquid crystal display element sandwiching a liquid crystal solidified composite dispersed and held in a solidified matrix, the substrate A and the electrode A are transparent, and the surface of the electrode A on the liquid crystal solidified composite side has fine irregularities. and, the surface of the liquid crystal and solidified matrix composite side electrode B with reflective surface using a material that reflects light to the electrode B and the substrate B is provided is flat, the center line average roughness of the uneven surface of the electrode a R _a Satisfies the relationship of 0.03 · G < _Ra <0.3 · G, where G is the average interelectrode gap, and the pitch of the uneven surface of the electrode A is 4 μm or more. Liquid crystal display device. 2. An electrode A is provided on a substrate A, an electrode B is provided on a substrate B, and a substrate A and a substrate B are arranged so that the electrodes A and B face each other. In a transmission-scattering type liquid crystal display device sandwiching a liquid crystal solidified compound compound dispersed and held in a solidified material matrix, a substrate A
And the electrode A is transparent, the surface of the electrode A on the liquid crystal solidified compound side has a fine uneven surface, and the electrode B or the substrate B is provided with a reflective surface using a material that reflects light, surface of the liquid crystal and solidified matrix composite body side is flat, the substrate a
A fine uneven surface is provided, and the concave surface derived from the uneven surface of the substrate A is formed.
A liquid crystal display device wherein a convex surface is formed on an electrode A, and an outer surface of the substrate A is provided with an antireflection coating by a multilayer interference film. 3. A substrate A having a fine uneven surface provided thereon.
2. The liquid crystal display element according to claim 1, wherein an uneven surface derived from the uneven surface is formed on the electrode A. 4. The liquid crystal display device according to claim 1, wherein an active element is disposed on the substrate B. 5. A liquid crystal display element according to claim 1, 2, 3 or 4, wherein a halftone is displayed by applying a voltage lower than a saturation voltage by the drive circuit. Liquid crystal display device.