JPH07128637A - Optical element - Google Patents

Abstract

PURPOSE:To form a soft focus image occurring no noise without necessitating a complex circuit by generating a slope on potential impressed between one side electrode and the other side electrode and area-controlling a light transmission state of a liquid crystal. CONSTITUTION:An electrode 3 is provided with lower resistance parts 7 on both end parts in the longitudinal direction, and the interval between both lower resistance parts 7 becomes a higher resistance part 9. When a voltage is impressed so that a prescribed potential difference is generated between the electrodes 3, 5, the liquid crystal between the electrodes 3, 5 is changed in its orientation state by the prescribed potential difference, and becomes a light scattered state. Then, when the prescribed potential difference is generated over the whole area between the electrodes 3, 5, the whole area becomes the light scattered state. However, by making one or plural number of contacts 11a-11g among the contacts 11a-11g provided on one side of the electrode 3 lower potential, no prescribed potential difference are generated in the vicinity of the contacts 11a-11g. When no set prescribed potential difference are generated, no orientation state of the liquid crystals are changed until occurring the light scattering, and the liquid crystals of the parts become the light transmission state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element capable of easily forming a soft focus image.

[0002]

2. Description of the Related Art Conventionally, in order to create a soft focus photograph in the field of photography, a soft focus filter is attached to a camera at the time of photographing to process the image at the time of photographing. It is also possible to soft-focus an image of a negative film that has been taken and print it on photographic paper. There is also a demand for forming a soft focus image in fields other than such photographic printing, and it is desired that a soft focus image can be easily formed even in a copying machine using analog light.

To perform soft focus processing when copying the contents of an original image with a copying apparatus, a soft focus filter is arranged between the original image and the photosensitive material, and the photosensitive material is scattered by the original image that has passed through the soft focus filter. Is exposed for a predetermined time. The soft focus filter has a function of scattering light, and the soft focus processing is performed using scattered light. In order to obtain scattered light without using such a soft focus filter, for example, a liquid crystal having a function of scattering light may be used, and an electric field may be applied to the liquid crystal to cause a light scattering state of the liquid crystal. Then, if the light-sensitive material is exposed to light that has passed through the liquid crystal causing the light-scattering state, the image formation on the light-sensitive material can be blurred.

As a technique for blurring an image by using a liquid crystal, Japanese Patent Publication No. Sho 64-10819 and Japanese Patent Laid-Open No. Sho 61-16982.
No. 3, JP-A-1-257820, and JP-A-62.
-220926 has a thing as described. Japanese Examiner Sho 64
Japanese Patent Laid-Open No. 10819 discloses a technique in which a matrix electrode is used to generate a light scattering state for each predetermined region. In Japanese Patent Laid-Open No. 61-169823, a segment electrode is used to generate a light scattering state in each predetermined region,
A technique for performing soft focus processing only on a predetermined area is disclosed. Japanese Patent Laid-Open No. 1-257820 discloses a photosensitive material in which a liquid crystal member is arranged so as to be located between a subject and a photosensitive material in a photographing camera or the like, and the light scattering state of the liquid crystal member is partially controlled. It is described that the blurring process is applied to the image exposed to the. Japanese Unexamined Patent Publication No. 62-220926 discloses a technique in which a potential gradient is generated in pixel units to generate a light scattering state.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
819, the above-mentioned JP-A-61-169823,
The technique disclosed in Japanese Patent Laid-Open No. 1-257820 controls the light transmission of a predetermined area by means of the matrix electrode and the segment electrode, and there is a problem that the circuit configuration for that purpose becomes complicated. Moreover, since the light scattering region is set by the shape of the matrix electrode or the segment electrode, the portion such as the black matrix between the electrodes becomes the boundary of the pixel,
This becomes a mask, and there is a problem that noise is generated in the image and the image quality is deteriorated. Further, the above-mentioned JP-A-62-22
Since the technique of Japanese Patent No. 0926 controls the light scattering state by generating a potential gradient in each pixel, a circuit configuration that generates a potential gradient in each pixel is required in addition to the circuit configuration of the electrodes that configure each pixel. Therefore, the circuit configuration becomes more complicated.

An object of the present invention is to solve the above-mentioned conventional problems, and to provide an optical element that can easily form a noise-free soft focus image without requiring a complicated circuit.

[0007]

The above object of the present invention can be achieved by the following constitutions. (1) An optical element in which a liquid crystal is sandwiched between opposed electrodes to generate a gradient in a potential applied between one electrode and the other electrode to control the light transmission state of the liquid crystal in an area.

(2) One electrode having a high potential of the same level applied to both ends of the longitudinal shape and having a contact for low potential between the both ends, and the other electrode arranged to face the electrode via a liquid crystal. And a potential difference is generated between both electrodes and a low potential is set to the contact to generate a potential gradient between the both ends of the one electrode and the contact, thereby transmitting light of liquid crystal. An optical element that controls the state of the area.

(3) A high potential of the same level is applied to the peripheral edge of the sheet, and one electrode having a contact for low potential in a portion surrounded by the peripheral edge is arranged opposite to the electrode via a liquid crystal. A liquid crystal having the other electrode, causing a potential difference between both electrodes, and setting a low potential at the contact to generate a potential gradient between the peripheral portion of the one electrode and the contact. An optical element that controls the light transmission state of the area.

[0010]

By controlling the light transmission state of the liquid crystal sandwiched between the counter electrodes by generating a potential gradient without keeping the potential between the counter electrodes constant, the threshold value and the potential gradient at which the alignment state of the liquid crystal changes. The area in which the alignment state of the liquid crystal changes is determined based on the above relationship, and the area can be controlled without setting pixels in the optical element. Therefore, the area in which the light is transmitted can be controlled without requiring a complicated circuit configuration. Further, since no pixel is set in the optical element, there is no black matrix for pixel setting or the like that does not block light and an unnecessary mask is prevented, and a noise-free image can be formed.

In order to generate a potential gradient, it is sufficient to apply a voltage uniformly to the electrodes and then set a low potential to a part of the electrodes. Further, in order to uniformly apply a voltage to the electrodes, it is preferable that the low resistance portion sandwiches or surrounds the high resistance portion in the electrode shape, and it is preferable to apply the voltage to the high resistance portion via the low resistance portion. . When the optical element is for slit exposure, the optical element is preferably formed in a longitudinal shape extending in the same direction as the slit light. In this case, one of the electrodes is configured to have a low resistance portion at both longitudinal end portions and a high resistance portion between both low resistance portions, and a contact for low potential is provided on the long side of the high resistance portion. Set up. By providing the low potential contact on one of the long sides of the longitudinal shape, a potential gradient can be formed between the low potential contact and the low resistance portions (high potential contacts) at both ends.

Since the contact for low potential is on one of the long sides, the potential gradient goes from the low resistance portion at both ends to the contact for low potential. Further, since the distance from both ends of the low resistance part of the electrode in the short side direction to the contact for low potential is different, the inclination angle of the potential gradient is also changed. Therefore, the region of the threshold potential where the light transmission state changes intersects obliquely with the sub-scanning direction of slit exposure. Therefore, when the slit light passes through a region where the threshold potential is oblique to the sub-scanning direction, this portion is exposed by the light adjusted by the liquid crystal and the combined light of the light that is not adjusted at all, and is not adjusted by the dimming unit. The boundary with the light section becomes inconspicuous.

For surface exposure, one electrode integrally has a low resistance portion on the periphery of a planar high resistance portion having a predetermined size, and a liquid crystal is sandwiched between the other electrode and the opposite electrode. Then, an optical element is configured. By providing a low potential contact in the high resistance part, a potential gradient can be generated between this contact and the low resistance part at the periphery. Around the contact for low potential,
Since a potential gradient that spreads almost radially occurs, the threshold potential becomes a closed curve, and different transmission states of light are obtained inside and outside this closed curve.

The type of liquid crystal that can be used in the present invention may be transparent without application of an electric field and in a scattering state when an electric field is applied, or conversely, it is in a scattering state when no electric field is applied and becomes transparent when an electric field is applied. It may be one. In the present invention, DSM (dynamic scattering mode, dynamic scattering mode), PC (phase change mode, phase transition mode), PDLC (polymer dispersed liquid crystal) can be used as the liquid crystal. Considering the time of transparency, DSM is the most transparent and is therefore preferable.

First, the dynamic scattering type liquid crystal will be described. For liquid crystal devices called Dynamic Scattering Modes (DSM), pages 195 to 230 of “Liquid Crystals Applications and Uses” (1990, World Scientific) edited by Vilendra Bahadur. It is described in the page and the references cited therein. The dynamic scattering type liquid crystal has a nematic liquid crystal sandwiched between a transparent electrode and two transparent substrates on which an alignment treatment is applied. The liquid crystal compound or composition enclosed therein usually has a negative anisotropy of dielectric constant, has a rather low resistivity of about 10 ¹⁰ ohm cm or less, and has anisotropy of conductivity (molecular weight). The difference obtained by subtracting the conductivity in the direction orthogonal to the conductivity in the major axis direction) is positive. Further, usually, an ionic compound (hereinafter abbreviated as a dopant) is added at 10 to 1000 ppm.

Many known compounds exhibiting dynamic scattering action were known before 1980, for example, Schiff bases represented by N-p-methylbenzylidene-p-butylaniline and p-substituted phenyl. , P-substituted benzoic acid esters can be used. In addition to this, all nematic liquid crystals exhibiting dynamic scattering operation can be used.

Vertical alignment treatment and horizontal alignment treatment are known as alignment treatments for liquid crystal devices, and both of them are used for the dynamic scattering mode. Therefore, in order to meet the object of the present invention, essentially any alignment treatment can be used in the present invention as long as the light scattering of the liquid crystal is extremely small in the absence of applied voltage. Among them, the cell subjected to the vertical alignment treatment is advantageous over other alignment methods because it has high transmittance in the absence of applied voltage and good three-dimensional symmetry of light diffusion. As the orientation treatment method, for example, treatment with a silane coupling agent, treatment with a polymer such as polyimide, or the like can be used, and rubbing is preferably performed as necessary. As the dopant, a quaternary organic ammonium salt such as tetrabutylammonium bromide is typically used. Here, carboxylate may be used as the counter anion. Further, charge transfer complexes represented by tetracyanoquinodimethane (TCNQ) and tetrathiafulvalene (TTF) can also be used.

Although the dynamic scattering type liquid crystal can be driven by direct current or alternating current, alternating current driving is preferable from the viewpoint of device life. At that time, the suitable frequency and voltage largely depend on the liquid crystal composition, the kind and concentration of the dopant, and the temperature. The dynamic scattering type liquid crystal does not scatter light passing through the liquid crystal layer when a voltage equal to or lower than a voltage (threshold voltage) applied to the electrodes on the substrate is applied. When a voltage higher than the threshold voltage is applied, the light passing through the liquid crystal layer is scattered. The degree of scattering changes depending on factors such as the liquid crystal material, the alignment film forming conditions, the cell thickness, and the applied voltage.

Such a property of the dynamic scattering type liquid crystal is extremely suitable for the purpose of the present invention in which the original image is subjected to soft focus processing to be copied. That is, the light diffusing ability is 5 ° to 30 ° or more in the half width of the angle, which is sufficient for soft focus printing. Moreover, since the degree of diffusion can be controlled by the applied voltage, it is possible to make a system having more flexibility than using a diffusion plate having a fixed diffusing ability.

Next, a phase change type liquid crystal (Phase Change Mode Liq
uid Crystal) is explained. The phase transition type liquid crystal is also called a phase change type liquid crystal. In the phase transition type liquid crystal, a phase change from a cholesteric (Ch) phase having a helical molecular arrangement to a vertically aligned nematic (N) phase or vice versa is caused by the strength of an electric field. When the electric field is weak, the Ch phase having a spiral structure is taken, but when the electric field is strong, the spiral structure is dissolved and the phase changes to the N phase. The Ch phase forms a focal conic structure and scatters light, but the N phase does not scatter light and the element becomes transparent at this time. The phase transition type liquid crystal is an element utilizing this electro-optical effect, but since it utilizes the scattering of light, a polarizing element is not required and a bright element can be obtained. These are described in the following documents. JJ Wysocki et a
l., Phys. Rov. Lett., 20, 1024 (1968), GH Heil
meier and LA Zanoni, Appl. Phys. Lett., 13, 91
(1968), H. Malchior et al., Appl. Phys. Lett., 21,
392 (1972).

Next, the polymer dispersed liquid crystal will be described.
The polymer dispersed liquid crystal has a structure in which a nematic liquid crystal droplet is completely or partially surrounded by a polymer matrix.
Here, if the ordinary refractive index of the liquid crystal and the refractive index of the polymer are combined so that when the electric field is applied to the device, the liquid crystal is oriented in the direction of the electric field and the refractive indices of the liquid crystal and the polymer match. On the other hand, when the liquid crystal is transparent, when the electric field is not applied, the liquid crystal is randomly aligned due to the alignment regulating force from the polymer, so that the refractive index of the liquid crystal and the polymer do not match and light is scattered.

A liquid crystal light control member using such a polymer-dispersed liquid crystal does not require a polarizing plate and can obtain a bright screen. In addition, since it can be continuously formed into a film, it is easy to make cells and have a large area. The polymer-dispersed liquid crystal has various names as described below depending on the dispersion form and the like, and these can be used in the present invention.

NCAP (Nematic Courvilinear Alligned)
Phase): The feature is that the liquid crystal is microencapsulated and put into a resin and hardened. Product name "UMU" (manufactured by Nippon Sheet Glass Co., Ltd.). (Japanese Patent Publication No. 3-52843, U.S. Patent Application No. 302,780, JL Fergason, 1985, SID Dig.
Tech. Papers 68p) PDLC (Polymer Dispersed Liquid)
Crystal): Characterized by forming by using phase separation between liquid crystal and polymer. (JW Doane et al., Appl, Phys.
Lett., 48 (4), 269 (1986)) PNLC (Polymer Network
Liquid Crystal): The polymer matrix is characterized by being a UV polymer compound and having a three-dimensional network structure. Developed by Dainippon Ink and Chemicals. (Takeuchi et al., 15th Liquid Crystal Conference 206 (1989))

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a principle diagram of an optical element of the present invention using liquid crystal. The optical element has a structure in which a liquid crystal is sandwiched between a pair of transparent counter electrodes, but only the counter electrode is shown in FIG. The optical element 1 is a light control filter used for slit exposure, and both electrodes 3, 5 are formed in a long shape extending in the main scanning direction of slit light. The first electrode 3 has a low resistance portion 7 at both ends in the longitudinal direction, and a high resistance portion 9 is provided between the both low resistance portions 7. The second electrode 5 is a solid electrode having a uniform resistance on the entire surface.

The high resistance portion 9 of one electrode 3 needs to be transparent, and ITO, for example, can be used.
Further, the low resistance portion 7 may also be ITO, or a commonly used metal electrode. In addition, the other counter electrode 5
Also needs to be transparent, for example ITO can be used. The low resistance portion 7 is for uniformly applying a voltage to the high resistance portion 9, but it may be omitted and the voltage may be directly applied to both ends of the high resistance portion 9.

As shown in FIG. 2, the optical element 1 has a sectional structure in which a liquid crystal compound is held between two alignment films, and an insulating film (for example, Si) is provided outside the alignment film (for example, polyimide).
O ₂ ), a transparent electrode, a glass substrate, and an antireflection film are sequentially layered. A liquid crystal is sandwiched between the pair of transparent counter electrodes 3 and 5, and these are integrally fixed to the exposure glass or the like. As the liquid crystal sandwiched between the electrodes 3 and 5,
Those that change from a transparent state to a light scattering state by applying a voltage,
Alternatively, a material that changes from a light-scattering state to a transparent state by applying a voltage can be used, but in this embodiment, a material that changes to a light-scattering state by applying a voltage is used.
As the liquid crystal having such characteristics, a nematic liquid crystal having a negative dielectric anisotropy, for example, ZLI-4330, ZLI-2806, ZLI-45 manufactured by E. Merck.
18, ZLI-4318 and the like can be used.

The low resistance portions 7 on both ends of the first electrode 3 and the second
A predetermined voltage is applied between the electrode 5 and the electrode 5, and the liquid crystal in the portion to which the voltage is applied changes its alignment state and becomes a light scattering state. At this time, a voltage is applied to the first electrode 3 so as to have a higher potential than that of the second electrode 5. One or a plurality of contacts 11 are provided on one side of the high resistance portion 9 of the first electrode 3. The contact 11 is set to a potential lower than the potential of the low resistance portions 7 at both ends.
A plurality of a to 11g are provided, and the contacts 11a to 11g can be grounded independently and the potential can be set to 0V. In the illustrated example, the potential of the low potential contact 11 is 0V.
However, the potential of the low potential contact 11 may be lower than the potentials of the low resistance portions 7 at both ends.

When a voltage is applied between the first electrode 3 and the second electrode 5 so as to generate a predetermined potential difference, both electrodes 3,
The liquid crystal between 5 changes its alignment state due to this predetermined potential difference and becomes a light scattering state. Therefore, if a predetermined potential difference is generated across the entire surface between the first electrode 3 and the second electrode 5,
The entire surface is in a light scattering state. However, by setting one or a plurality of contacts 11a to 11g among the contacts 11a to 11g provided on one side of the first electrode 3 to a low potential, the set predetermined potential difference is generated in the vicinity of the contacts 11a to 11g. It will not occur. If the predetermined potential difference that has been set does not occur, the alignment state of the liquid crystal does not change until light scattering occurs, and the liquid crystal in this portion is in the light transmitting state.

Therefore, by appropriately selecting the contact 11 and grounding it, it is possible to set a region in which a predetermined potential difference does not occur, and to set a transparent region in the optical element 1 in the light scattering state. You can As described above, in the optical element 1 having the above-described configuration, the alignment state of the liquid crystal changes in the voltage application portion and the liquid crystal becomes a light scattering state. Therefore, by controlling the voltage application region to the liquid crystal by selecting the low potential contact. The area of the light scattering area can be controlled.

The area control of the light scattering area in the optical element 1 having the above structure will be described below. As shown in FIG. 3A, when a low potential portion is set at the contact 11d at the center of the electrodes 3 and 5 in the longitudinal direction, a low potential portion is formed between the electrodes 3 and 5 as shown in FIG. 3B. A potential gradient V1 is generated. Since a predetermined voltage is applied to the low resistance portions 7 at both ends of the optical element 1, the potential difference is large, but the potential difference between the counter electrodes 3 and 5 gradually decreases toward the center point C, The potential difference becomes 0 near the center point C. Although the gradient of the process from the high potential portion to the low potential portion is linear, the rate of decrease of the potential increases in a curve toward the low potential portion, and as a result, only the low potential contact 11d becomes 0V. Instead, the vicinity of the low potential contact 11d also becomes 0V.

The potential difference between the counter electrodes 3 and 5 is a predetermined threshold potential S.
Light scattering does not occur below H1 (shown by the dotted line in FIG. 3B), so that the optical element 1 is in a transparent state in a region near the center where the potential difference is lower than the threshold potential SH1. On the other hand, in the regions at both ends where the potential difference is higher than the threshold potential SH1,
The alignment state of the liquid crystal is changed and a light scattering state is generated.
As shown in (A), light scattering portions are formed on both sides of the transparent portion near the center in the longitudinal direction.

Optical element 1 to which voltage is applied as described above
Is arranged with the longitudinal direction aligned with the main scanning direction of the slit light at the time of slit exposure, and scanning exposure is performed with the slit light transmitted through the optical element 1, scattered light is obtained in the vicinity of both ends of the main scanning, Soft-focus exposure is performed on the photosensitive material corresponding to this portion. That is, the photosensitive material is exposed to scattered light in the vicinity of both ends in the longitudinal direction to form a blurred image, and is exposed to light in the vicinity of the center with light that is not dimmed to form a sharp image.

In FIG. 3, if the contact 11d is changed to another contact on the left and right, the transparent region and the light scattering region also change according to the change of the contact. In this case, the low potential contacts 11a to 11g
Can be set simultaneously to control the transparent and light scattering regions. If multiple low potential contacts are set, the area between these contacts will always be transparent. In addition, after fixing the contact 11 for low potential, the voltage applied to the low resistance portion 7 is increased or decreased to change the potential gradient V as shown by an imaginary line in FIG.
2, V3 can be formed to control the area. Similarly, the area control can be performed by changing the threshold potential to set the threshold potentials SH2 and SH3 indicated by phantom lines in FIG. Further, the area can be controlled by increasing or decreasing the potential of the low potential contact 11.

The above structure has a plurality of low potential contacts 11a.
11g are independently provided, but a low potential contact can be set at an arbitrary position by providing a slider contacting the long side of the high resistance portion 9 as a low potential contact. In such soft focus area control, since there is no control in pixel units or in segment units, a complicated circuit configuration is not required, and soft focus area control is performed with a simple configuration. be able to.

As described above, the low potential contact is set to 0V.
When it is set to 0V, a predetermined range in the vicinity thereof becomes 0V. When this potential distribution state in the plane is shown in FIG. 4, the semicircular region in the vicinity of the low potential contact has 0V. On the other hand, since the potential differences between the points 7a to 7d of the low resistance portion 7 at both ends and the low potential contact 11d are equal, the equipotential portion spreads radially around the low potential contact 11d, and the equipotential line becomes an arc. . Therefore, since the threshold potential SH1 that changes the alignment state of the liquid crystal is also an arc, the boundary line between the light transmitting portion and the light scattering portion is also an arc. In slit exposure, since sub-scanning is performed in the direction of arrow D, in the area of width W, the photosensitive material is exposed with the combined light of the light transmitted through the transparent portion and the light transmitted through the light scattering portion.
Therefore, the formed image has an effect that the boundary between the sharp image and the soft focus image is not clear, and the boundary between the sharp image and the soft focus image is in a gradation state.

Next, a second embodiment of the optical element will be described with reference to FIG. FIG. 5A is a principle diagram of the second embodiment. The optical element 21 is composed of a pair of circular electrodes 23 and 25 arranged so as to face each other. The first electrode 23 has a low resistance portion 27 at its peripheral portion and a high resistance portion 29 at other portions near the center other than the low resistance portion 27. Has become. The second electrode 25 is a solid electrode having a uniform resistance on the entire surface. The high resistance portion 29 of the first electrode 23 can be provided with one or a plurality of low potential contacts 31, and in the example shown in FIG. 5A, one contact 31 is provided in the center. .

By applying a voltage between the low resistance portion 27 of the first electrode 23 and the second electrode 25 such that a predetermined potential difference that causes the liquid crystal to be in a light scattering state is applied, the optical element 21
The entire surface of can be made into a light scattering state. Where the first
By setting the potential of the low potential contact 31 of the electrode 23 of the electrode 23 lower than that of the low resistance portion 27 at the peripheral edge, a light scattering state occurs between the vicinity of the low potential contact 31 and the second electrode 25. Therefore, the set potential difference is not generated. Therefore,
In the vicinity of the center of the optical element 21, a light scattering state does not occur and the optical element 21 is in a transparent state, whereas in the vicinity of the peripheral edge, a light scattering state occurs, and soft focus processing can be performed only in the vicinity of the peripheral edge.

In the second embodiment, the number and positions of the low potential contacts 31 are not limited to the positions shown in FIG. 5A, but can be set arbitrarily. The low potential contact 31 is the first
The electrode 23 may be provided concentrically or eccentrically. Also in the second embodiment, the low potential contact 31
By controlling the position, the potential of the low potential contact 31, the voltage applied to the low resistance portion 27, the threshold potential for causing the liquid crystal to generate the light scattering state, and the like. Area can be controlled.

The optical element 21 of the second embodiment is suitable for processing a light flux having a circular cross section, and when the optical element 21 is used by being incorporated in a photographing device such as a photographic camera or a video camera. , You can easily take soft focus. In particular, even when soft focus is applied only to a predetermined area, pixel control and segment control for that purpose are unnecessary, and since only the control of the low potential contact 31 is required, a complicated circuit configuration is unnecessary. Therefore, soft focus processing can be performed with a simple configuration. Although the electrode shape of the second embodiment is circular, the electrode may be rectangular or the like, and may have any shape according to the application.

The optical element of each of the above embodiments may be driven by direct current or alternating current, and in the case of alternating current, sine wave or triangular wave may be used. In each of the configurations of the above-described examples, a liquid crystal ZLI-4318 manufactured by Merck & Co., in which 0.04 wt% of tetrabutylammonium bromide is added, is used as a liquid crystal, and an alternating sine wave of 50 Hz is used for the first electrode and the second electrode When a crest value of 0 V to ± 70 V was applied between and, and the contact for low potential was grounded, a light scattering state occurred only in a predetermined region, and the light scattering portion could be area controlled.

[0041]

According to the present invention, a potential gradient is generated without making the potential between the opposing electrodes constant, and the light transmission state of the liquid crystal sandwiched between the opposing electrodes is controlled, whereby the pixel is formed in the optical element. Since the area can be controlled without setting, it is possible to control the area of the light transmission state with a simple structure without the need for a complicated circuit configuration such as when controlling in pixel units or in segment units. it can. Moreover, since the present invention does not set pixels, it is possible to prevent the boundary between pixels from becoming a mask as in the conventional case, and it is possible to form an image without noise.

[Brief description of drawings]

FIG. 1 is a principle diagram of an optical element of the present invention.

FIG. 2 is a sectional view of an optical element of the present invention.

3A and 3B are operation explanatory views of the first embodiment of the optical element of the present invention, FIG. 3A is a principle diagram, and FIG. 3B is a graph showing a relationship between a potential gradient and a threshold value.

FIG. 4 is a plane distribution state diagram of a potential.

5A and 5B are operation explanatory diagrams of a second embodiment of the optical element of the present invention, FIG. 5A is a principle diagram, and FIG. 5B is a graph showing a relationship between a potential gradient and a threshold value.

[Explanation of symbols]

 1, 21 Optical element 3, 23 First electrode 5, 25 Second electrode 7, 27 Low resistance part 9, 29 High resistance part 11, 31 Low potential contact

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuru Sawano 200 Onakazato, Fujinomiya-shi, Shizuoka Prefecture Fuji Photo Film Co., Ltd.

Claims (3)

[Claims] 1. An optical element for controlling an area of a light transmission state of liquid crystal by sandwiching liquid crystal between electrodes arranged to face each other to generate a gradient in a potential applied between one electrode and the other electrode. 2. One electrode having a high potential of the same level applied to both ends of the longitudinal shape and having a low potential contact between the both ends, and the other electrode opposed to the electrode via a liquid crystal. And a potential difference between both electrodes is generated and a low potential is set at the contact to generate a potential gradient between the both ends of the one electrode and the contact, so that the liquid crystal light transmission state is obtained. An optical element that controls the area. 3. One electrode having a low potential contact in a portion surrounded by the peripheral portion and having a high potential applied to the planar peripheral portion, and the other electrode opposed to the electrode via a liquid crystal. Of the liquid crystal to generate a potential difference between the electrodes and to set a low potential to the contact to generate a potential gradient between the peripheral portion of the one electrode and the contact. An optical element that controls the area of light transmission.