JP2870028B2 - Liquid crystal optical device and driving method thereof - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission-scattering type liquid crystal optical device using a light absorber and a driving method thereof.

[Prior art] Twisted nematic (TN) well known from the past
Liquid crystal optical elements are used in many fields, taking advantage of features such as low power consumption and low cost. However, this TN mode has a disadvantage that transmitted light is largely cut off and the display becomes dark because two polarizing films are used.

On the other hand, two modes of a dynamic scattering (DS) and a phase transition (PC) are known for a liquid crystal optical element that operates on light scattering.

Neither the DS mode nor the PC mode uses a polarizing plate, so there is an advantage that a wide viewing angle can be obtained.However, the former is a current effect type in which a conductive substance is added to the liquid crystal, so that the power consumption increases. It has the disadvantage that the reliability of the phase is reduced.

On the other hand, since the operating voltage also depends on (distance between electrodes / pitch of liquid crystal) in the latter case, there is a difficult problem that a uniform gap is required with high accuracy when the area is to be increased. .

On the other hand, recently HGCraighead et al.
The method disclosed in T., 40 (1) 22 (1982) takes advantage of the characteristic that the liquid crystal has a refractive index anisotropy. Specifically, the liquid crystal is impregnated in a porous material and the presence or absence of voltage application is determined. The transmission and scattering are controlled by changing the refractive index of the liquid crystal by adjusting the refractive index with the porous body.

This method is a useful method that can overcome the disadvantages of the DS mode and PC mode in principle without using a polarizing plate. Similar elements are disclosed in JP-T-58-501631, JP-A-60-252687, JP-T-61-502128, and the like. The use of a light absorber in combination with this is also disclosed in JP-T-61-501345, JP-A-59-178428, and the like.

[Problems to be Solved by the Invention] In order to color a transmission-scattering type liquid crystal optical device using such a film-like liquid crystal layer, the following has been proposed.

It has also been proposed to change the color of the illumination light as a transmission type, but it is difficult to partially change the color,
There is a problem that the display is washed out with respect to strong external light and the display becomes invisible. It is also known that a dichroic dye is mixed into a liquid crystal to change the color.
Again, it is difficult to partially change the color, and there is a problem that a display that is common in a liquid crystal optical device using a dichroic dye looks blurred.

Means for Solving the Problems The present invention has been made to solve the above-mentioned problem, and has a film-like liquid crystal layer in which liquid crystal is dispersed and held in a resin matrix between a pair of electrodes. Is sandwiched, light is transmitted when the refractive index of the liquid crystal matches the refractive index of the resin matrix, and the refractive index of the liquid crystal is scattered when the refractive index of the liquid crystal does not match the refractive index of the resin matrix. The refractive index of the resin matrix is selected, a color filter is provided on the front substrate, a light absorber is provided on the back side of the film-like liquid crystal layer, and a part of the film-like liquid crystal layer is always A liquid crystal optical device characterized by being in a light transmitting state, and a liquid crystal optical device characterized in that the light absorber is a colored louver, and a part of a film-like liquid crystal layer, in particular, a background The part is a sign of voltage A liquid crystal optical device, which is always in a light transmitting state irrespective of an applied state, and as a film-like liquid crystal layer thereof, a mixture of liquid crystal and a raw material of a resin matrix is cured so that the liquid crystal becomes a resin matrix. Liquid crystal optical device, characterized by using a film-like liquid crystal layer to be dispersed and held therein,
It is another object of the present invention to provide a driving method of a liquid crystal optical device that performs driving such that a voltage is applied to a portion not desired to be displayed without applying a voltage to a portion desired to be displayed.

In the liquid crystal optical device of the present invention, a color filter is provided on the substrate on the front side of the liquid crystal optical element capable of electrically controlling the scattering state and the transmission state, and the light absorber is provided on the back side of the film-like liquid crystal layer. Thus, a bright and beautiful color display can be realized by the black color of the light absorption and the color of the color filter.

In the liquid crystal optical element of the liquid crystal optical device of the present invention, a film-like liquid crystal layer in which liquid crystal is dispersed and held in a resin matrix is sandwiched between a pair of substrates with electrodes, and a scattering state and a transmission state are controlled by applying a voltage. Anything that can be used can be used. A color filter is provided on the substrate on the front side of the liquid crystal optical element, and a light absorber is provided on the back side of the film-like liquid crystal layer.

In the present invention, as the film-like liquid crystal layer of the liquid crystal optical element, any liquid crystal in which a liquid crystal is dispersed and held in a resin matrix can be used. Specifically, the liquid crystal may form independent liquid bubbles and may be encapsulated in a microcapsule state, the liquid bubbles may communicate with each other, or a portion of a resin matrix having many fine holes. May be filled with liquid crystal.

When such a film-like liquid crystal layer is sandwiched between a pair of substrates with electrodes and a voltage is applied between the electrodes, the refractive index of the liquid crystal changes depending on the state of application of the voltage, and the refractive index of the resin matrix increases. When the relationship with the refractive index of the liquid crystal changes, the liquid crystal enters a transmission state when the two have the same refractive index, and enters a scattering state when the two have different refractive indices.

Specifically, the refractive index of the cured product constituting the resin matrix while the voltage is being applied is adjusted to match the ordinary light refractive index (n _o ) of the liquid crystal.

Thereby, light is transmitted when the refractive index of the obtained cured product matches the refractive index of the liquid crystal substance, and when the refractive index does not match, the light is scattered (cloudy). Since the scattering property of this element is higher than that of the conventional DSM (dynamic scattering mode) liquid crystal optical element, if a color filter is provided on the front substrate as described later, the film-like liquid crystal layer Since the color becomes white, the color of the front color filter can be seen and a beautiful display can be easily obtained.

The film-like liquid crystal layer of the present invention is usually prepared by mixing a liquid crystal and a raw material of a resin matrix, and then casting and curing the mixture on an electrode substrate, or a substrate with a pair of electrodes as in a normal liquid crystal cell. May be sealed with a sealing material, the mixture may be injected from the injection port and cured, so that the liquid phase is dispersed and held in the resin matrix.

Above all, as a raw material of the resin matrix, a light-curable resin or a thermosetting resin curable in a closed system is used, and a solution obtained by dissolving the resin in a liquid crystal is photo-cured or heat-cured, thereby improving productivity. In addition, the above-mentioned manufacturing methods of both casting supply and pouring are applicable. In particular, it is preferable to use a photocurable resin and perform photocuring.

The refractive index of the resin matrix, by keeping to match the n _o index of refraction of the liquid crystal, when no voltage is applied, the liquid crystal which is not arranged, by the refractive index of the resin matrix difference, scattering state ( That is, the color filter arranged in front of it is seen. For this reason,
The color of the color filter is visible in the background, and only the part to which the voltage is applied is in a transmissive state, and light is absorbed by the light absorber on the back side, so even if there is a color filter on the front, it will look black .

In the present invention, during this curing step, only a specific portion is cured by applying a sufficiently high voltage, or is cured while being heated to a temperature higher than the phase transition point of the liquid crystal, so that the portion always transmits light. The state can be made to appear black. Information such as a company mark that the user always wants to display can be formed in such a normally transparent portion.

When using a photo-curable resin and curing with a high voltage applied, an electrode is also required in that part,
Other parts can be cured at the same time and can be cured in one step. Also, in the case of curing while being heated to a temperature higher than the phase transition point of the liquid crystal, the other parts are cured by lowering the temperature in a separate step. By providing and curing, patterning can be performed freely. For this reason, the latter manufacturing method is used in the case where all parts other than the display part are always light transmitting parts.

In the present invention having such a portion through which light is transmitted, the driving method of the liquid crystal optical device is such that a voltage is not applied to a portion to be displayed and a voltage is applied to a portion not to be displayed. Can be a method. In particular, this effect is significant when all parts other than the display part are always light-transmitting parts and the color of the light absorber is used. That is, when the background part other than the display part is blackened by the light absorber, the color of the color filter is visible in the display part in a state where no voltage is applied.

Taking a bar graph display as an example, if normal driving is performed in response to the input, the portion to which the voltage is applied becomes a transparent state and looks black, and the entire portion becomes black at the maximum input. This makes it difficult to see, so that the whole is black when there is no input, and it is easier to see when there is an input and the color is displayed according to the size of the input.

For this reason, it is easy to see if the color of the color filter is made visible so as not to apply a voltage to a portion to be displayed and a voltage is applied to a portion not to be displayed so that the color looks black.

In the present invention, it is preferable to use a liquid crystal optical element in which the refractive index of the resin matrix matches the refractive index (n _o ) of the liquid crystal to be used, and it is preferable to make them completely match, but this has an adverse effect on the transmission state. It can be used if they are almost the same, but not so much. Specifically, the difference in refractive index
It is preferable to keep it at about 0.15 or less. This is because the liquid crystal swells the resin matrix and approaches the refractive index of the liquid crystal more than the refractive index of the resin matrix itself, so even if there is a difference of this degree, light will be almost transmitted, This is because the light is absorbed by the light absorber on the back side, and the light absorber appears black.

FIG. 1 is a sectional view showing a basic configuration of the liquid crystal optical device of the present invention.

In FIG. 1, reference numeral 1 denotes a substrate on the back side of plastic, glass or the like, and 2 denotes ITO (In ₂ O ₃ -Sn) formed on the inner surface thereof.
O ₂ ), electrodes such as SnO ₂ , 3 is a front substrate such as plastic or glass, 4 is an electrode such as ITO, SnO ₂ formed on the inner surface, and 5 is formed on an electrode 4 of the front substrate. A color filter, 6 is a light absorber laminated on the back side of the substrate 1 on the back side, 7 is a sealing material for sealing the two substrates, 8 is a film-like liquid crystal layer sandwiched between the substrates, 9 is an observation. Person.

FIG. 2 is a cross-sectional view showing a configuration using a louver of the liquid crystal optical device of the present invention.

In FIG. 2, reference numeral 11 denotes a back substrate, 12 denotes an electrode formed on the inner surface, 13 denotes a front substrate, 14 denotes an electrode formed on the inner surface, and 15 denotes an electrode 14 and a substrate 13 of the front substrate. A color filter formed in between, 16 is a light absorber by a louver arranged on the back side of the back substrate 11, 17 is a sealing material, 18
Denotes a film-like liquid crystal layer, 19 denotes an observer, and 20 denotes a light source disposed on the back side of the light absorber. In this example, observer 19
Is viewed from the front of the liquid crystal optical device. For this reason, the louver blades of the light absorber 16 allow the light from the light source 20 to directly
It is tilted about 45 ° so that it does not get into the eyes.

This electrode may be a transparent electrode on both substrates, or a black opaque electrode only on the back substrate.
A transparent electrode may be formed on a black light absorber. When both substrates are made of transparent electrodes, a light absorber is laminated on the back side of the back substrate. Of course, the substrate itself may be a black substrate. In the above description, the light absorber is black, but may be another color such as dark blue. In this case, in the light transmitting state, the color mixture with the light absorber is visible in the portion where the color filter is provided, and the color of the light absorber is visible in the portion where the color filter is provided. This light absorber may be formed on the entire surface, may be formed partially, or may be a light absorber of a plurality of colors. However, a light absorber is formed in a portion where the display is changed by applying a voltage.

As a method for manufacturing the light absorber, specifically, a black material may be deposited, black ink may be printed, a black sheet or printed matter may be laminated, and may be provided on the entire surface, or may be patterned. May be.

Further, by using a louver colored black or the like as the light absorber, the degree of freedom of the position of the light source is increased.
For example, a light source is disposed on the back side, and a louver is used to block direct light from the light source from directly entering the viewer's eyes. By coloring this louver, it can be used as a light absorber. Specifically, if a louver colored black is used, light from the light source is obliquely incident on the liquid crystal optical element, the light scattering portion looks bright or white in color of the color filter, and the light transmitting portion looks black. For this reason, the louver blades may be arranged so that the observer can see the louver blades and the light from the light source does not directly enter the eyes. Thereby, the light source and the light guide plate can be arranged on the back side facing the observer.

In the present invention, a color filter is arranged on the front substrate. If this color filter is a substrate on the front side, it may be formed on the electrode, may be formed between the electrode and the substrate, may be arranged on the front side of the substrate, or may be the substrate itself. May be used as a colored substrate. However, in the case of disposing the color filter on the outer surface of the substrate, it is preferable to provide the color filter on the inner surface of the substrate because the color filter is easily conspicuous even when the film-like liquid crystal layer is in a transmission state. As the production method, various known color filter production methods such as an electrodeposition method, a printing method, a photosensitive resist method, a sticking method, a vapor deposition method, and a dyeing method can be used.

This color filter may be formed on the entire surface, may be formed partially, or may be a plurality of color filters. The smaller the scattering by the color filter, the better, and the haze value is 10% or less, preferably 5% or less.

In the present invention, since the color filter is formed on the substrate on the front side, sufficient luminance and color purity can be obtained even in an environment where ambient light is strong.

The liquid crystal optical device of the present invention may be configured such that an ultraviolet cut filter or the like is laminated on the outside of the liquid crystal optical element, characters, graphics, etc. may be printed, or a plurality of liquid crystal optical elements may be used. It may be.

Furthermore, in the present invention, when coloring the structure in which the liquid crystal optical element is exposed to the outside, it is preferable to laminate a protective plate such as a glass plate or a plastic plate outside the liquid crystal optical element. Thereby, even if the surface is pressurized, the risk of breakage is reduced, and safety is improved.

In the liquid crystal optical device of the present invention, as a raw material of the resin matrix constituting the above-mentioned film-like liquid crystal layer, there are monomers, oligomers of various resins, polymers dissolved by a solvent, and the like, which are mixed with liquid crystal to form a mixture. Used. In this case, it is preferable to use a material in which the raw material of the resin matrix is dissolved in the liquid crystal to form a homogeneous solution, but a material in a latex state can also be used.

When the mixture is cast and supplied on the substrate, a solvent that distills off the solvent or generates by-products such as gas at the time of curing can be used.However, when the liquid crystal is injected into the cell and post-cured, it is used. In addition, a mixture that does not require solvent evaporation in a closed system and can be cured without generating by-products such as gas during curing is used.

Therefore, it is preferable to use a photocurable resin from the viewpoint of productivity, and in particular, it is preferable to use a photocurable vinyl resin.

Specifically, a photocurable acrylic resin is exemplified, and a resin containing an acrylic oligomer which is polymerized and cured by light irradiation is particularly preferable.

The liquid crystal used in the present invention includes a nematic liquid crystal, a smectic liquid crystal, and the like, and the composition may be used alone or in an operating temperature range. It can be said that use is more advantageous. In particular, the use of a nematic liquid crystal is preferred.

When a photo-curable resin is used, the liquid crystal used for the film-like liquid crystal layer preferably dissolves the photo-curable resin uniformly, and the cured product after light exposure does not dissolve or is difficult to dissolve. When using the composition,
It is desirable that the solubility of each liquid crystal be as close as possible.

When manufacturing the film-like liquid crystal layer, the resin matrix and the liquid crystal may be mixed with the raw material of the resin matrix and the liquid crystal so as to have a ratio of about 5:95 to 75:25. It may be used as an object.

When manufacturing a film-like liquid crystal layer, cells can be formed and injected from the injection port as in a conventional ordinary liquid crystal optical element, but a mixture of the raw material of the resin matrix and the liquid crystal is supplied on a substrate with electrodes By superposing the opposing substrates, a liquid crystal optical element can be manufactured with extremely high productivity.

The gap between the substrates can be operated at 5 to 100 μm, but in consideration of the applied voltage and the contrast at the time of on / off, it is appropriate to set the gap to 7 to 40 μm in the case of the film-like liquid crystal layer. .

In the liquid crystal optical element of the present invention, a dichroic dye, a simple dye, or a pigment may be added to the liquid crystal, or a liquid crystal colored as a resin matrix may be used.

By using a plastic substrate as the substrate with electrodes, a long liquid crystal optical element using a continuous plastic film can be easily manufactured.

In addition, since the liquid crystal optical element of the present invention is generally small in size, even if a cell is formed using a glass substrate in the same manner as in a normal liquid crystal optical element and then injected, there is almost no reduction in productivity.

By making the film-like liquid crystal layer in this way, the risk of short circuit between the upper and lower transparent electrodes is low, and there is no need to strictly control the orientation and the substrate gap as in a normal TN type liquid crystal optical element, A liquid crystal optical element capable of controlling the transmission state and the scattering state can be manufactured with extremely high productivity.

In this liquid crystal optical element, for further protection when the substrate is plastic or thin glass, a protective plate such as plastic or glass is laminated on the outside, or the substrate is made of tempered glass, laminated glass, lined glass, or the like. Various applications such as good are preferred.

The liquid crystal optical element of the present invention is used by adding a driving means. As the driving means, one which can apply an AC voltage of about several tens of volts as described later may be used. The electrode pattern may be a solid electrode on the entire surface, but it is preferable that the electrode of a desired pattern is colored and displayed when a voltage is applied.

In this case, two or more color filters may be used for one pattern to display a plurality of colors, or two or more patterns may be used to display a plurality of colors.

Further, when the liquid crystal optical element is cured, a part thereof is fixedly displayed, that is, light is always transmitted.

Specifically, when using a mixture of a liquid crystal and a photocurable resin in which the ordinary light refractive index (n _o ) of the liquid crystal and the refractive index of the resin matrix match, when curing by irradiation with light, By curing while applying a voltage to only the specific portion or by heating to a phase transition temperature or higher, the specific portion becomes an ordinary light transmitting portion. For this reason, in a state where no voltage is applied, the specific part is in a transmission state, the specific color is, for example, black by the light absorber, and the other parts are in a scattering state, so that the color of the color filter is visible. .
Next, when a voltage is applied to a desired portion, the portion is also in a light transmitting state, so that the light absorber becomes a specific color, for example, black.

Such a fixed display portion may be formed by exposing twice using a light-shielding mask, or may be patterned by irradiating a laser or the like. Further, the light absorber of the present invention may be partially provided, and this light absorber may be used as a light shielding mask at the time of light exposure.

By always setting the portions other than the display portion in the light transmitting state, it is possible to perform color display using a color filter on a black background without providing a light shielding film. In particular, in a normal TN-type liquid crystal optical device, when light is not shielded by a light-shielding film in a cell, the appearance is reduced due to parallax when viewed from an oblique direction. However, in the liquid crystal optical device of the present invention, the film-shaped liquid crystal layer is fixed by being cured by using a light-shielding mask, so that the light-shielding film remains in the cell even when viewed obliquely when the observer observes. This is the same as provided, and the appearance is less likely to deteriorate due to parallax.

In the liquid crystal optical device of the present invention, when applying a voltage for driving, an AC voltage that changes the alignment of the liquid crystal may be applied. Specifically, an AC voltage of about 5 to 100 V and about 10 to 1000 Hz may be applied.

In the liquid crystal optical device of the present invention, an active element such as a TFT is formed in each pixel, and a dot matrix display or a television display can be performed by using a three-color or single-color color filter of RGB.

[Function] According to the present invention, a color filter is provided on a substrate on the front side of a film-like liquid crystal layer in which liquid crystal is dispersed and held in a resin matrix, and a light absorber is provided on a substrate on the back side corresponding to the back side of the film-like liquid crystal layer. ing.

Therefore, when the refractive index of the liquid crystal matches the refractive index of the resin matrix, light is transmitted and the light is absorbed by the light absorber on the back side, and the color of the light absorber such as black is seen. Conversely, when the refractive index of the liquid crystal does not match the refractive index of the resin matrix, light is scattered, so that the color of the color filter on the front side can be seen.

Since the liquid crystal optical device of the present invention utilizes such a principle, a bright display of the color of the light absorber such as black and a specific color can be obtained. For example, a black display on a red background or the like is obtained. In particular, since the present invention uses phase change,
The polarizing filter does not need to be used, and the color of the color filter does not look dark and dull as in the conventional TN type liquid crystal display device, but looks brighter.

In addition, since the display is of a reflective type, the display does not become invisible even when receiving strong external light such as direct sunlight.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to Examples and Reference Examples.

Reference Example 1 A black light absorbing plate made by Tsutsuna Plastics Co., Ltd. was attached and laminated on the back side of a glass substrate with ITO on which a bar graph was patterned to produce a back side substrate.

I face the patterned ITO on the backside substrate
Fuji Hunt's resist type color filter, 2μm thick, on glass substrate ITO panned with TO
It was formed and manufactured as a front substrate.

The back side substrate and the front side substrate were sealed around the periphery thereof with a 20 μm spacer interposed therebetween to form a cell.

7 parts of 2-ethylhexyl acrylate and 15 parts of 2-hydroxyethyl acrylate, 24 parts of an acrylic oligomer ("M-1200" manufactured by Toa Gosei Chemical Co., Ltd.), and 0.9 parts of "Darocur 1116" manufactured by Merck as a photocuring initiator. As a liquid crystal, 64 parts of [E-8] manufactured by BDH was uniformly dissolved to produce a liquid crystal mixture.

This liquid crystal mixture was injected into the above-described cell, and irradiated with ultraviolet rays for 30 seconds to expose a liquid crystal optical device. In this liquid crystal optical device, the refractive index of the cured product that constitutes the resin matrix is equal to the ordinary light refractive index (n _o ) of the liquid crystal.
Therefore, when no voltage was applied, the refractive indices of the two were different, and the whole was in a scattered (cloudy) state, and the color of the color filter was visible. The portion where the color filter was not formed looked white.

When this liquid crystal optical device was viewed from the front while being tilted at 45 ° so that light was not regularly reflected, the bar graph portion appeared to be the color of the color filter, and the other background appeared to be white. When an AC voltage (AC30V, 50Hz) is applied to this,
Only the bar fluff portion to which the voltage is applied becomes a transparent state,
Black color was visible.

For this reason, by performing a reverse drive of applying a voltage only to a segment that is not desired to be displayed, the bar graph is driven, so that an easy-to-read display is obtained.

Example 1 ITO in which a bar graph and a frame around it are patterned
The attached glass substrate was used as the back side substrate.

I face the patterned ITO on the backside substrate
A resist type color filter manufactured by Fuji Hunt Co., Ltd. was formed to a thickness of 2 μm on ITO of a glass substrate on which TO was patterned, and was manufactured as a front side substrate.

The back side substrate and the front side substrate were sealed around the periphery thereof with a 20 μm spacer interposed therebetween to form a cell.

Placing a mask with an opening only in the frame part around the bar graph, applying an AC voltage (AC 100 V, 50 Hz),
Exposure was performed by irradiating with ultraviolet light for 30 seconds. Next, the mask was removed, and the whole was irradiated with ultraviolet rays for 30 seconds without applying a voltage to complete the exposure, thereby completing the curing of the resin in the liquid crystal mixture.

Thereafter, a black light absorbing plate made by Tsutsuna Plastics Co., Ltd. was attached to the back side of the back substrate to manufacture a liquid crystal optical device.

When this liquid crystal optical device was viewed from the front while being tilted at 45 ° so that light was not regularly reflected, the bar graph portion appeared in the color of the color filter in the black frame, and the other background appeared white. When an AC voltage (30 V AC, 50 Hz) was applied thereto, the bar fluff portion and the frame to which the voltage was applied became transparent, and black was seen.

Reference Example 2 A liquid crystal optical device was manufactured in the same manner as in Reference Example 1, except that the color filter of Reference Example 1 was formed on the entire surface of the front substrate.

This liquid crystal optical device was the same as Reference Example 1 except that the color of the color filter was visible in all portions where the film-like liquid crystal layer was in the light scattering state.

Reference Example 3 The light absorber of Reference Example 1 was replaced with a louver having black wings, and a light source was arranged on the back side. It was kept out of the direct observer's eyes.

In this example, the light source was provided at a position facing the observer. However, light from the light source did not directly enter the observer's eyes, and the appearance was similar to that of Reference Example 1.

Example 2 The liquid crystal optical device of Reference Example 3 was exposed by irradiating with ultraviolet rays for 30 seconds while arranging a mask corresponding to the display portion of the bar graph, raising the temperature above the phase transition temperature of the liquid crystal. Then, the temperature was lowered to room temperature, the mask was removed, and the whole was irradiated with ultraviolet rays for 30 seconds to expose, thereby completing the curing of the resin in the liquid crystal mixture.

In this liquid crystal optical device, the bar graph portion appeared to be the color of the color filter, and the other background appeared to be black. When an AC voltage (30 V AC, 50 Hz) was applied thereto, only the bar fluff portion to which the voltage was applied became a transmission state, and black was seen.

Therefore, by performing a reverse drive of applying a voltage only to a segment that is not desired to be displayed, and driving the bar graph, an easy-to-read display in which the color of the color filter is displayed on a black background is obtained. Was.

[Effects of the Invention] As described above, according to the present invention, a film-like liquid crystal layer in which liquid crystals are dispersed and held in a resin matrix is provided, a color filter is provided on a front substrate, and a light absorber is provided on a back substrate. When the refractive index of the liquid crystal matches the refractive index of the resin matrix, light is transmitted, and the color of the light absorber such as black on the back side can be seen. Conversely, when the refractive index of the liquid crystal does not match the refractive index of the resin matrix, light is scattered, so that the color of the color filter on the front side can be seen.

Since the liquid crystal optical device of the present invention utilizes such a principle, a bright display of the color of the light absorber such as black and the specific color of the color filter can be obtained. For example, a black display or the like on a red background is obtained. Further, if a color filter is not provided in a background portion where no voltage is applied, red and black display or the like can be obtained on a white background. In particular, since the present invention uses a phase change, it is not necessary to use a polarizing film.
The color of the color filter is dark and dull, unlike the TN type liquid crystal display device, and it looks brighter.

Also, if a color filter is not provided in the background part where no voltage is applied, the white part will not be dark gray or green or red as in the conventional TN type liquid crystal display device, the white part will be more white and bright. appear.

Also, without using a light shielding film inside and outside the cell, a desired portion can be colored black or the like by a combination of the light absorber and the light transmitting portion, and the light use efficiency is increased, so that the display brightness is further increased. Can be.

The present invention is also applicable to various applications within a range that does not impair the effects of the present invention.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a basic configuration of the liquid crystal optical device of the present invention. FIG. 2 is a cross-sectional view showing a configuration using a louver of the liquid crystal optical device of the present invention. Substrates: 1, 3, 11, 13 Electrodes: 2, 4, 12, 14 Color filters: 5, 15 Light absorbers: 6, 16 Sealants: 7, 17 Film liquid crystal layer: 8, 18 Observers: 9, 19 Light source: 20

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02F 1/1333

Claims (3)

(57) [Claims] A film-like liquid crystal layer in which liquid crystal is dispersed and held in a resin matrix is sandwiched between a pair of substrates with electrodes, and light is transmitted when the refractive index of the liquid crystal matches the refractive index of the resin matrix. The refractive index of the liquid crystal and the refractive index of the resin matrix are selected so that light is scattered when the refractive index of the liquid crystal does not match the refractive index of the resin matrix. A liquid crystal optical device, wherein a light absorber is provided on the back side of a liquid crystal layer, and a part of the film-like liquid crystal layer is always in a light transmitting state regardless of a voltage application state. 2. The liquid crystal optical device according to claim 1, wherein the light absorber is a colored louver. 3. A method for driving a liquid crystal optical device, wherein the liquid crystal optical device according to claim 1 or 2 is driven so as to apply a voltage to a portion not to be displayed without applying a voltage to a portion to be displayed. .