JP2005091743A - Optical deflection device, image display device, optical writing device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical deflection device which has further improved response, with which uniform deflection is obtained even for a large area thereof, which is realized with a comparatively simple construction and which is made small-sized and reduced in cost, and to provide an image display device utilizing the optical deflection device, an optical writing device equipped with the optical deflection element and an image forming device using the optical writing device. <P>SOLUTION: The optical deflection device 30 has the optical deflection element 21 having a liquid crystal layer 12 constructed with a chiral smectic A phase and placed between substrates 11, an alignment layer 14 aligning liquid crystal molecules forming the liquid crystal layer 12 in parallel to the substrates 11 and a plurality of long electrodes 15 placed in a direction nearly parallel to a disposition plane of the substrate 11 and an electric field forming means 22 forming an electric field in the direction nearly parallel to the disposition plane by using the electrodes 15, and deflects linearly polarized light transmitting the optical deflection element 21 by changing intensity and a direction of the electric field formed with the electric field forming means 22. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical deflection device using an optical deflection element that changes the direction of light according to an electric signal, an image display device such as an electronic display device such as a projection display or a head-mounted display using the optical deflection device, and such an optical deflection device. And an image forming apparatus using a light emitter array or the like as an image forming engine, and a copier, facsimile, printer or the like using these optical writing apparatuses, or a complex machine thereof, that is, an MFP.

[Definition]
In the present specification and claims, an “optical deflection element” refers to an optical signal that is deflected by an external electric signal, that is, the optical axis of outgoing light is shifted in parallel to incident light, or It means an optical element that can be rotated at a certain angle, or a combination of both to switch the optical path. The “light deflection amount” is the amount of movement when the optical path or the optical axis is shifted in parallel or rotated. In particular, the magnitude of the shift is referred to as the “optical path shift amount” or simply “shift amount” for the optical deflection operation of the parallel shift, and the rotation amount is referred to as “optical path rotation angle” or simply “shift amount” for the optical deflection operation by rotation. It shall be called “rotation angle”. The “light deflecting device” means a set of devices that include such a light deflecting element and that shift or rotate the incident optical path in parallel.

  The “pixel shift element” is an image display element in which a plurality of pixels that can control light according to image information is two-dimensionally arranged, a light source that illuminates the image display element, and an image displayed on the image display element. An optical member for observing the pattern, and a light deflecting means for deflecting the optical path between the image display element and the optical member for each of a plurality of subfields obtained by dividing the image field in time. Means light deflecting means in an image display device that displays an image pattern in which the display position is shifted according to the deflection of the optical path for each field, thereby increasing the apparent number of pixels of the image display element. To do. Therefore, basically, it can be said that the light deflection element and the light deflection device defined above can be applied as the light deflection means.

[Background Technology]
Various types of optical deflection devices using an optical deflection element that changes the direction of light in accordance with an electric signal have been disclosed. Also, an image display device using such an optical deflection device, and light provided with such an optical deflection device. Various writing devices have been disclosed. As an example, [Patent Document 1] to [Patent Document 6] will be described below.

  [Patent Document 1] proposes an optical deflection switch that can obtain a large deflection, has high deflection efficiency, and can arbitrarily set a deflection angle and a deflection distance. As a constitution, two transparent substrates are arranged opposite to each other at a predetermined interval, a vertical alignment process is performed on the opposed surfaces, and smectic A-phase ferroelectric liquid crystal is sealed between the transparent substrates. The liquid crystal element includes a driving device in which an electrode pair is arranged so that an AC electric field can be applied in parallel with the smectic layer and an AC electric field is applied to the electrode pair.

In other words, the refraction angle and the direction of displacement of the polarized light incident on the liquid crystal layer can be changed by the birefringence due to the inclination of the liquid crystal molecules by using the electroclinic effect of the smectic A phase ferroelectric liquid crystal.
However, in such a configuration, it is necessary to increase the cell gap in order to obtain a large deflection angle, and there is a problem that it is difficult to stabilize the alignment of the liquid crystal with a large cell gap.

  In [Patent Document 2], an optical deflector having a low voltage drive and a high-speed response, in which the correlation between the magnitude of the deflection angle and the operating voltage is eliminated by making the optical path direction and the electric field direction non-parallel. Has proposed. Specifically, smectic A-phase ferroelectric liquid crystal aligned in a certain direction in advance is used and sealed between suitable transparent substrates. The electric field at the time of driving is applied in a direction perpendicular to the optical path direction, and the orientation direction of the liquid crystal is changed by the electric field to change the refractive index of the liquid crystal that the incident light senses. That is, by changing the refractive index of the liquid crystal while preserving the polarization state of incident light, it is possible to cause a light deflection action.

At this time, the shape of the electrode contributing to the generation of the electric field is a triangle, a trapezoid, or a lens shape, and the electrode shape is configured to provide a deflection action and a light collection action.
In such a configuration, it is possible to provide a deflection action with low electric field driving in a minute region, but when the area is large, it cannot be driven with a low voltage. In addition, when the area is large, there is a problem in that the electric field strength varies depending on the location, and a uniform deflection action cannot be achieved.

[Patent Document 3] proposes an optical deflector capable of individually deflecting the propagation direction of a light beam with respect to a plurality of incident light beams. This uses a substrate in which sawtooth-shaped grooves are formed on a transparent substrate, encapsulates nematic liquid crystal aligned in a predetermined direction in a sawtooth-formed substrate and a flat substrate, and generates an electric field by dividing electrodes corresponding to each sawtooth shape. It is configured to change the refractive index of the liquid crystal by applying it, and it is possible to individually deflect the light incident on each sawtooth shape.
However, in such a configuration, a driving means corresponding to each sawtooth shape is required, and the configuration becomes complicated and the cost becomes high in order to realize it. Further, since the liquid crystal used is a nematic liquid crystal, there is a problem that the response is very slow.

  In [Patent Document 4], as a means for displaying a display image formed by discrete pixels with high resolution by wobbling, a ferroelectric property exhibiting a chiral smectic C phase or a smectic A phase having an electroclinic effect. An optical modulation element having a configuration in which a liquid crystal cell and a birefringent medium are combined and an image display apparatus having the same have been proposed. In this configuration, the polarization direction is rotated by 90 ° with a ferroelectric liquid crystal exhibiting high-speed response, and the optical axis of the emitted light is shifted in a predetermined direction by the birefringent medium.

However, such an image display apparatus has the following problems.
(1) Optical crystals that function as birefringent plates are generally expensive and costly.
(2) Since the optical path traveling straight through the optical birefringent plate and the optical path traveling obliquely are switched, an optical path length difference occurs between the two optical paths, and the focal position shifts.
(3) Since the amount of movement of the optical path is determined by the birefringence and thickness of the optical crystal, the amount of movement of the optical path is fixed.

  In [Patent Document 5], the exposure position is changed electro-optically by combining a ferroelectric liquid crystal cell that rotates the plane of polarization by 90 degrees and a birefringent plate while using a low-resolution light emitting element array. There has been proposed an optical writing apparatus that can perform printing at a high resolution by using an imaging position control means.

  Specifically, a pair of transparent electrodes and a horizontal alignment film are formed on a pair of transparent substrates, and a liquid crystal layer composed of a ferroelectric liquid crystal composed of a chiral smectic C phase is sandwiched between the two substrates. ing. If a birefringent plate is provided after this liquid crystal cell, the light travels straight when the plane of polarization is an ordinary light component with respect to the birefringent plate, and the light is shifted in parallel when the plane of polarization is an extraordinary light component. Means can be configured.

  At this time, the shift amount of the optical path is determined by the direction and thickness of the optical axis of the birefringent plate, and optical writing is performed by interposing the optical path shift means thus configured between the light emitter array and the recording body. A device can be realized. Therefore, by using this optical writing apparatus for an image forming apparatus, it is possible to print at a high resolution even when a low-resolution light emitter array is used. The ferroelectric liquid crystal used in this configuration can be switched at a relatively high speed.

However, such an optical writing device has the following problems.
(1) Since the surface stable ferroelectric liquid crystal cell is required to control the cell gap with high accuracy, it is difficult to manufacture the surface stable ferroelectric liquid crystal cell with an area corresponding to the size of the light emitter array.
(2) An optical crystal that functions as a birefringent plate is generally expensive, and using an optical crystal having an area corresponding to the size of the light emitter array increases the cost.
(3) Since the optical path traveling straight through the optical birefringent plate and the optical path traveling obliquely are switched, a difference in optical path length occurs between the optical paths, and the focal position shifts.
(4) Since the amount of movement of the optical path is determined by the birefringence and thickness of the optical crystal, the amount of movement of the optical path is fixed.

  In [Patent Document 6], a pair of transparent substrates, a liquid crystal comprising a chiral smectic C phase having a homeotropic alignment filled between the substrates, and at least one set of electric field applying means for applying an electric field to the liquid crystals It is set as the structure provided with. As another configuration, a transparent pair of substrates, a liquid crystal composed of a homogeneous smectic C phase filled between the substrates, and at least one set of electric field applying means for applying an electric field to the liquid crystals are provided. At least one of the substrates sandwiching the liquid crystal has a sawtooth shape.

In such a configuration, a liquid crystal composed of a chiral smectic C phase is used. Therefore, compared to a conventional optical deflection element, the cost is increased due to the complicated configuration, the size of the apparatus is increased, the light loss is reduced, and the optical noise is reduced. In addition, it is possible to improve the dullness of response in the conventional nematic liquid crystal and the like, and high-speed response is possible.
However, it is desired that a uniform deflection amount can be obtained even in a large area and that high-speed response is further improved.

JP-A-9-133904 Japanese Patent No. 2579426 JP 7-92507 A JP-A-7-20417 JP-A-8-118726 JP 2002-328402 A

The problems of the prior art described above can be summarized as follows.
1. Increased response speed
2. Uniformity of deflection amount as the area increases
3. High cost and large equipment due to complicated structure

  Therefore, the present invention has high responsiveness, can obtain a uniform deflection amount even in a large area, can be realized with a relatively simple configuration, is high in cost due to a complicated configuration, and is small and low in size. Optical deflecting device using cost optical deflecting device, projection display using this optical deflecting device, image display device such as electronic display device such as head-mounted display, and light emitter array having such optical deflecting device and image forming engine And an image forming apparatus such as a copying machine, a facsimile, a printer, or the like using these optical writing apparatuses, or a complex machine thereof such as an MFP.

  In order to achieve the above object, the invention described in claim 1 includes a pair of substrates facing each other, a liquid crystal layer formed by a chiral smectic A phase and positioned between the substrates, and liquid crystal molecules forming the liquid crystal layer. An optical deflection element having an alignment film that is horizontally aligned on the substrate, a plurality of electrodes that are disposed substantially in parallel with each other and that are long in a direction substantially parallel to the surface on which the substrate is disposed, Electric field forming means for forming an electric field in a direction substantially parallel to the surface, and transmits the light deflection element by changing the intensity and / or direction of the electric field formed by the electric field forming means. There is an optical deflecting device for deflecting linearly polarized light.

  According to a second aspect of the present invention, in the optical deflecting device according to the first aspect, the alignment direction of the liquid crystal molecules and the extending direction of the electrodes are substantially parallel.

  According to a third aspect of the present invention, in the optical deflection apparatus according to the first or second aspect, the alignment direction of the liquid crystal molecules is substantially parallel to the direction of linearly polarized light transmitted through the optical deflection element. To do.

  According to a fourth aspect of the present invention, in the optical deflecting device according to any one of the first to third aspects, the electric field forming means is disposed between the electrodes, and between the electrodes. It has a resistance element for gradually increasing or decreasing the strength of the electric field in the direction from the electrode located on one end side of the electrodes toward the electrode located on the other end side.

  According to a fifth aspect of the present invention, in the optical deflecting device according to the fourth aspect, the resistance value of the resistance element is changed from an electrode located on one end side of the electrodes to an electrode located on the other end side. It is characterized by changing periodically in the direction of heading.

  According to a sixth aspect of the present invention, in the optical deflection element according to any one of the first to fifth aspects, at least one of the substrates has a surface having a sawtooth cross section on the side facing the other. It is characterized by.

  According to a seventh aspect of the present invention, there is provided a pair of substrates opposed to each other, a liquid crystal layer constituted by a chiral smectic A phase and located between the substrates, and an orientation for horizontally aligning liquid crystal molecules forming the liquid crystal layer on the substrate. An optical deflection element having a film and an electrode disposed substantially parallel to each other and substantially parallel to the surface on which the substrate is disposed; and for forming an electric field in a direction substantially perpendicular to the surface disposed by the electrode. Electric field forming means, and at least one of the substrates has a surface having a saw-tooth cross section on the side facing the other, and the strength and / or direction of the electric field formed by the electric field forming means. The linearly polarized light transmitted through the light deflecting element is deflected by changing.

  According to an eighth aspect of the present invention, in the optical deflecting device according to any one of the first to seventh aspects, the optical deflecting device further comprises a temperature detecting means for detecting the temperature of the optical deflecting element.

  The invention according to claim 9 is the optical deflection apparatus according to claim 8, further comprising temperature control means for controlling the temperature of the light deflection element based on the temperature detected by the temperature detection means.

  The invention according to claim 10 is an image display element in which a plurality of pixels are two-dimensionally arranged, an optical member for observing an image displayed on the image display element, and the optical member and the image display element. The light deflection element according to any one of claims 1 to 9 disposed between and a deflection of light by the deflection element in synchronization with a timing at which an image is displayed on the image display element. Thus, the image display apparatus includes image display control means for increasing the apparent number of pixels of the image observed by the optical member.

  According to the eleventh aspect of the present invention, a plurality of light emitting members arranged at predetermined intervals and emitting light toward the writing position, and the respective light emitted from these light emitting members are arranged in the direction in which the light emitting members are arranged. An optical writing apparatus comprising the optical deflection element according to any one of claims 1 to 9 for deflecting and making an interval of light at a writing position smaller than the predetermined interval.

  According to a twelfth aspect of the present invention, there is provided the optical writing device according to the eleventh aspect, wherein the light deflection element is disposed corresponding to each of the light emitting members.

  A thirteenth aspect of the present invention is an image forming apparatus having the optical writing device according to the eleventh or twelfth aspect.

  The present invention includes a pair of substrates facing each other, a liquid crystal layer constituted by a chiral smectic A phase and positioned between the substrates, an alignment film for horizontally aligning liquid crystal molecules forming the liquid crystal layer on the substrate, An optical deflection element having a plurality of electrodes that are arranged substantially in parallel and that are long in a direction substantially parallel to the arrangement surface of the substrate, and an electric field is applied in a direction substantially parallel to the arrangement surface by the electrodes. And deflecting linearly polarized light transmitted through the optical deflecting element by changing the intensity and / or direction of the electric field formed by the electric field forming means. Since it is in the device, it has high responsiveness, can perform analog modulation by the electroclinic effect, and can obtain a uniform deflection amount even in a large area from the configuration of lateral electric field drive by the line electrode structure. Compared with a conventional optical deflecting device combined with a birefringent medium, the optical deflecting device can be realized with a relatively simple configuration, can improve the high cost due to a complicated configuration, increase the size of the device, and provide a small and low cost optical deflecting device .

  If the alignment direction of the liquid crystal molecules and the extending direction of the electrodes are almost parallel, the applied electric field by the electrodes is almost perpendicular to the alignment direction of the liquid crystal molecules, and the optical axis of the liquid crystal molecules can be tilted efficiently. Therefore, it is possible to provide an optical deflecting device having high responsiveness and capable of analog modulation by the electroclinic effect.

  If the orientation direction of the liquid crystal molecules is substantially parallel to the direction of linearly polarized light transmitted through the light deflecting element, the average refractive index change of the liquid crystal layer by electric field control can be used efficiently. It is possible to provide an optical deflecting device that has high responsiveness and can perform analog modulation by the electroclinic effect.

  An electric field forming means is disposed between each of the electrodes, and the intensity of the electric field between each of the electrodes is directed from the electrode located on one end side of the electrodes to the electrode located on the other end side. If a resistance element for gradually increasing or decreasing in the direction is provided, the electric field strength between the electrodes can be changed to change the refractive index distribution of the liquid crystal so as to obtain a desired light deflection direction. It is possible to provide an optical deflecting device that can provide the same effects as those described above, has high responsiveness, and can perform analog modulation by the electroclinic effect.

  If the resistance value of the resistance element periodically changes in the direction from the electrode located on one end side of the electrodes to the electrode located on the other end side, the light deflection functions by the diffraction phenomenon. Therefore, the diffracted light generated from the refractive index distribution can be used as deflected light, so that the light utilization efficiency is high, the response is high, and the optical deflection device capable of analog modulation by the electroclinic effect is provided. Can do.

  If at least one of the substrates has a surface having a sawtooth shape on the side facing the other, the light deflection angle can be easily set by adjusting the pitch and depth of the sawtooth shape. Even if the gap between the substrates is narrow, a wide deflection angle can be obtained, and the response is high, and even if the gap between the substrates is small, a large deflection angle can be obtained. Can be provided.

  The present invention includes a pair of substrates facing each other, a liquid crystal layer constituted by a chiral smectic A phase and positioned between the substrates, an alignment film for horizontally aligning liquid crystal molecules forming the liquid crystal layer on the substrate, An optical deflection element having an electrode substantially parallel and having an electrode substantially parallel to the surface on which the substrate is disposed, and an electric field forming means for forming an electric field in a direction substantially perpendicular to the surface by the electrode. And has a high responsiveness by deflecting linearly polarized light that passes through the light deflecting element by changing the intensity and / or direction of the electric field formed by the electric field forming means. Because of the configuration of lateral electric field drive with a line electrode structure, it is possible to obtain a uniform deflection amount even in a large area, and it is a relatively simple configuration compared to a conventional optical deflection device combined with a birefringent medium. Current can, high cost of complex configuration, to improve the device size, it is possible to provide an optical deflecting device of small size and low cost.

  If the temperature detecting means for detecting the temperature of the light deflection element is provided, the temperature of the liquid crystal can be appropriately adjusted to obtain a stable light deflection amount, that is, a constant light deflection amount by detecting the temperature of the light deflection element. It is possible to provide an optical deflecting device that can detect whether or not the temperature is within a temperature range and prevent problems that occur when the temperature of the liquid crystal is outside the proper temperature range.

  If the temperature control means for controlling the temperature of the light deflection element based on the temperature detected by the temperature detection means is provided, a stable light deflection amount, that is, a constant light deflection amount can always be obtained for the liquid crystal temperature. It is possible to provide an optical deflecting device that can be kept within an appropriate temperature range and can reliably prevent problems that occur when the temperature of the liquid crystal is outside the appropriate temperature range.

  The present invention provides an image display element in which a plurality of pixels are arranged two-dimensionally, an optical member for observing an image displayed on the image display element, and between the optical member and the image display element. The light deflection element according to any one of claims 1 to 9 and the light deflection by the deflection element are changed in synchronization with a timing at which an image is displayed on the image display element. Since the image display apparatus has an image display control means for increasing the apparent number of pixels of the image observed by the optical member, the light display apparatus has the above-described effects and is uniform even in a large area. Since an image can be obtained, a high-definition and high-contrast image higher than the resolution of the used image display element can be displayed, and an optical deflecting device using a smectic A-phase liquid crystal is used. , Because the response speed of the deflection operation is very fast, there is no flickering or flickering that would be a problem when performing light deflection with a slow response speed, high definition, low contrast reduction, and a relatively simple configuration. In addition, it is possible to improve the high cost and the large size of the apparatus due to the complicated configuration, and to provide a small, low cost, high speed, high resolution, high quality image display apparatus.

  The present invention provides a plurality of light emitting members arranged at predetermined intervals and emitting light toward a writing position, and deflects each light emitted from these light emitting members in the direction in which the light emitting members are arranged. An optical writing apparatus having the optical deflection element according to any one of claims 1 to 9 for making the interval of light at a position smaller than the predetermined interval. The device has a device that switches the polarity of the electric field at high speed by the electrode switching operation, and the optical deflection device uses smectic A-phase liquid crystal, so the response speed of the optical deflection operation is very fast, and light emission It is possible to perform light irradiation in which the pitch between the members is complemented, so that even if a light emitting member having a low resolution is used, high-resolution light irradiation can be performed. Can be realized with a single configuration, a high cost due to complicated structure and improve the device size, small, low cost and high resolution at high speed, it is possible to provide an optical writing device with high image quality.

  Assuming that the light deflection elements are arranged corresponding to the light emitting members, even if the position of the light emitted from each light emitting member is deviated, the light deflection device can be controlled by driving control of the light deflection device, etc. Since the pixel pitch can be complemented by the interval, it is possible to provide a high-resolution, high-quality optical writing device that suppresses the influence of deterioration over time and is always stable over time.

  The present invention resides in an image forming apparatus having the optical writing device according to claim 11 or 12. Therefore, the image forming device having the optical writing device having the above-described effects and capable of forming an image with high resolution and high speed. An apparatus can be provided.

  As shown in FIG. 1 or FIG. 2, the optical deflection apparatus 30 according to the first embodiment of the present invention includes an optical deflection element 21 that is a liquid crystal cell that deflects transmitted light 20, and an electric field applied to the optical deflection element 21. Electric field applying means 22 as electric field forming means for applying. The optical deflection element 21 includes two transparent substrates 11 that are a pair of substrates facing each other, a liquid crystal layer 12 that is formed by a chiral smectic A phase and is positioned between the substrates 11, and a liquid crystal that forms the liquid crystal layer 12. An alignment film 14 serving as a horizontal alignment film for horizontally aligning the molecules 13 on each substrate 11 and the extending direction indicated by an arrow A are arranged on the surface of the substrate 11, that is, the coordinate system shown in the figure. A plurality of linear electrodes 15 that are substantially parallel to the YZ plane in (hereinafter simply referred to as “coordinate system”) and that are long in parallel with the alignment direction of the initial alignment of the liquid crystal molecules 13 indicated by the arrow B; A pair of spacers 16 for regulating the distance between the substrates 11 are provided.

  Each substrate 11 has a flat plate shape. The liquid crystal layer 12 is formed by filling a ferroelectric liquid crystal exhibiting a chiral smectic A phase. The alignment film 14 is disposed inside each substrate 11, that is, on the side where one substrate 11 faces the other substrate 11. Each spacer 16 is located inside each alignment film 14. Each electrode 15 extends inside the one substrate 11 in the Z-axis direction in the coordinate system and is covered with an alignment film 14. An electric field applying means 22 is connected to each electrode 15. The electric field applying means 22 is for forming an electric field substantially parallel to the arrangement surface of each substrate 11 by each electrode 15, and is equal between the power supply 17 for applying an alternating current or a voltage similar thereto and each electrode 15. And a resistance element 18 for providing a resistance of a magnitude. As a result, electric fields having the same magnitude are formed between the electrodes 15 by the electric field applying means 22 in the Y-axis direction in the coordinate system.

  The alignment direction B indicates the major axis direction of the liquid crystal molecules 13, that is, the liquid crystal director direction (also referred to as “liquid crystal director” as appropriate) in a state where no electric field is formed by the electric field applying means 22. The alignment film 14 is rubbed in the C direction, which is a direction parallel to the alignment direction B, in order to align the liquid crystal molecules 13 in the alignment direction B. As shown in FIG. 2, linearly polarized light 20 is transmitted through the light deflection element 21. The direction of linearly polarized light is the Z-axis direction in the coordinate system, the direction perpendicular to the paper surface in FIG. 2A, and the direction indicated by the arrow D in FIGS. 2B and 2C. The directions A, B, C, and D are all substantially parallel to each other, substantially coincide with the Z-axis direction in the coordinate system, and are parallel to the arrangement surface of each substrate 11. The direction from the one located on one end side of the substrate 11 toward the one located on the other end side, that is, the direction perpendicular to the Y-axis direction in the coordinate system.

  In this embodiment, the electrode 15 is formed only on one substrate 11, but may be formed on both substrates 11 as long as the horizontal electric field described above can be applied. The number, pitch, and width of the electrodes 15 are appropriately set according to the width of the light beam to be deflected, a desired deflection angle, and the like. In this embodiment, the number of lines is four for convenience. The electrode 15 is preferably made of a material having high transparency and easily forming a line-like pattern, and generally used ITO can be used. However, the present invention is not limited to this. For example, a metal electrode such as Cr can be used without any problem if the line width is very narrow and the amount of transmitted light is large.

  The alignment film 14 is formed on the inner surfaces of both the substrates 11. However, the alignment film 14 may be formed only on one of the substrates 11 as long as the liquid crystal director can be aligned horizontally with the surface on which the substrates 11 are disposed. As a material of the alignment film 14, a general alignment film such as polyimide used for TN liquid crystal, STN liquid crystal, or the like can be used. In order to align the alignment of the liquid crystal directors in a certain direction, it is preferable to apply a photo-alignment treatment together with the rubbing treatment or in place of the rubbing treatment. As the spacer 16, beads and ribs having a desired interval can be used.

  The liquid crystal material will be described. The “smectic liquid crystal” is a liquid crystal phase in which the major axis directions of liquid crystal molecules are substantially aligned and arranged in a layered manner while maintaining the major axis direction. With regard to such a liquid crystal, a liquid crystal phase in which the major axis direction of the liquid crystal molecules coincides with the normal direction of the smectic layer constituted by the liquid crystal molecules, that is, the layer normal direction is referred to as “smectic A phase”. A liquid crystal phase in which the major axis direction of the liquid crystal molecules is not aligned with the normal direction of the layer is called “smectic C phase”.

  Here, the electroclinic effect will be described. The electroclinic effect is a phenomenon in which the tilt of the orientation vector of liquid crystal molecules is induced by an electric field, and in the smectic A phase in which the major axis direction of the liquid crystal molecules coincides with the layer normal direction, This is a precursor phenomenon in the temperature region that causes a phase transition to a smectic C * phase in which the molecules are inclined. A model of the electroclinic effect is shown in FIG. First, consider a smectic A phase of a non-racemic liquid crystal having chiral chiral liquid crystal molecules and a dipole moment in the vertical direction.

  As shown in FIG. 3A, when the electric field E = 0, the liquid crystal molecules 31 are oriented perpendicularly to the smectic layer 32 and freely rotate around a long axis 33 parallel to the normal direction F of the smectic layer 32. doing. From this state, as shown in FIG. 3B, when an electric field (+ E) is applied in a direction parallel to the smectic layer 32, the liquid crystal molecules 31 are restrained from free rotation, and spontaneous polarization P is induced. Tilted by + θ. Further, as shown in FIG. 3C, when the electric field polarity is changed and the electric field (-E) is applied in the direction parallel to the smectic layer 32, the tilt direction is reversed to show the first order effect on the electric field.

Inclination direction is perpendicular to the direction of the electric field, the inclination angle theta of the liquid crystal molecules ^{_{31 θ = (ε ⊥ * -ε}} ⊥ 0) ε 0 E
Although it is proportional to the magnitude of the electric field, it tends to be saturated near the transition point. In this vicinity, it is theoretically explained from the minimum energy condition that it is proportional to E ^1/3 . ε _⊥ ^*, ε _⊥ ⁰ is the dielectric constant of the optically active substance and its racemate, respectively epsilon ₀ is the permittivity of vacuum. In addition, the polarization P and the inclination angle θ are obtained by using the electroclinic effect coefficient κ, P = κθ
There is a proportional relationship represented by κ is called an electroclinic coefficient, and details are omitted here. What is characteristic about responsiveness is that the response speed does not depend on the electric field strength, and a high-speed response of several μsec to several tens of μsec is obtained at an electric field strength of approximately 10 V / μm.

In the present invention, an optical deflection operation is performed by controlling the tilt angle of the liquid crystal director by an electric field by utilizing such an electric tilt effect.
Here, the light deflection operation will be described. Since the polarization direction of the incident light 20 to the light deflecting device 30 is constant, the refractive index felt by the incident light 20 depends on the liquid crystal director, in other words, the liquid crystal alignment.

  For example, when an electric field of (+ E) is applied, the liquid crystal director of the liquid crystal molecules 13 has an axis (not shown) penetrating the liquid crystal molecules 13 in the + Y axis direction in the coordinate system, as indicated by a solid line in FIG. At the center, the incident light 20 is inclined in the + Z-axis direction toward the traveling direction of the incident light 20, and the emitted light is deflected in the + Z-axis direction in the coordinate system. When an electric field of (−E) is applied, the liquid crystal director of the liquid crystal molecules 13 has an axis (not shown) penetrating the liquid crystal molecules 13 in the −Y axis direction in the coordinate system, as indicated by a solid line in FIG. In the center, the incident light 20 is inclined in the −Z-axis direction toward the traveling direction of the incident light 20, and the emitted light is deflected in the −Z-axis direction in the coordinate system.

  Therefore, by controlling the electric field, the liquid crystal director is tilted and the average optical axis of the liquid crystal layer is tilted by approaching the homeotropic alignment from the initial horizontal alignment, that is, the homogeneous alignment, due to the electroclinic effect. The refraction of the light changes, and the light deflecting operation of linearly polarized light can be performed by the same action as that of the uniaxial crystal. Since the light deflection direction can be set by the tilt of the liquid crystal director, the tilt of the liquid crystal director can be set and deflected by changing the intensity of the electric field formed by the electric field applying means 22 and / or the direction of the electric field, If the intensity of the electric field is analog-modulated, analog light deflection can be performed.

  Since the smectic A layer has spontaneous polarization and exhibits very high responsiveness, the optical deflection device 30 capable of high-speed and analog optical deflection operation is realized. Further, in this embodiment, since a plurality of line-shaped electrodes 15 are arranged in parallel to generate a horizontal electric field with respect to the arrangement surface of the substrate 11, the electric field strength can be uniformly applied even in a large area. A large area and uniform light deflection operation is possible.

  Further, since the extending direction A of each electrode 15 is set so that the direction of the electric field applied thereby is perpendicular to the alignment direction B of the liquid crystal molecules 13, for example, the direction of the electric field is inclined by 45 ° with respect to the direction B. As compared with the case where the direction A is determined as described above, the tilt of the optical axis of the liquid crystal molecules 13 by the electro-tilt effect can be performed efficiently. Further, the direction D of the linearly polarized light of the incident light 20 is parallel to the alignment direction B of the liquid crystal molecules 13, and the direction D is parallel to the direction formed by projecting the liquid crystal molecules 13 onto the arrangement surface of the substrate 11. The direction D coincides with the direction of the liquid crystal director, and the change in the refractive index due to the inclination of the liquid crystal director can be used efficiently.

  FIG. 5 shows an optical deflection apparatus 40 according to the second embodiment of the present invention. The description of this embodiment will be made with respect to parts different from those of the first embodiment, and the rest will be given the same reference numerals as those of the same embodiment, and the description of this embodiment will be replaced with the description of this embodiment. As shown in FIG. 5C, the light deflection element 41 of this embodiment has a flat plate-like substrate 42 facing the substrate 11 on which the electrode 15 is disposed. Inside, there is a surface 43 whose XZ section in the coordinate system has a sawtooth shape. The arrangement surface of the substrate 42 is parallel to the arrangement surface of the substrate 11. The alignment film 44 formed on the surface 43 has a sawtooth shape that matches the shape of the surface 43.

  As a method for forming the sawtooth shape of the substrate 42, there are a method of etching the substrate 42 by photolithography, a method of directly processing the shape by cutting and grinding, and the like. Further, there is a method in which a transparent plastic material is injection-molded using a mold product having a sawtooth shape formed by such a method, and is transferred to form a substrate 42. The electrode 15 is formed only on the smooth substrate 11. However, if the horizontal electric field can be applied to the arrangement surface of the substrates 11 and 42, the electrode 15 may be formed only on the substrate 42 or both the substrates 11 and 42. Good. The number, pitch, width, etc. of the electrodes 15 are appropriately set according to the width of the light beam to be deflected, a desired deflection angle, and the like. Further, a sawtooth shape can be used instead of the spacer 16. In this case, it is preferable to perform a process such as etching of an electrode surface to be contacted or providing an insulating film so as not to cause a short circuit.

  In this embodiment, since the sawtooth substrate 42 is used, since deflection is performed by refraction using the difference in refractive index between the liquid crystal layer 12 and the substrate 42, a larger deflection angle can be obtained than in the case of a flat plate. Can do. The light deflection angle is easily set by the pitch and depth of the sawtooth shape. Moreover, even if the gap between the two substrates 11 and 42 is small, a large deflection angle can be obtained, so that the optical deflection element 41 is suitable for miniaturization. The sawtooth shape may be provided on at least one of the substrates 11 and 42 as long as a horizontal electric field is obtained, and may be formed on the substrate provided with the electrode 15 or may be formed on both substrates.

  In addition, when it has a sawtooth shape, the liquid crystal molecules 13 are also aligned along a surface inclined to the arrangement surface of the substrate 42 constituting the sawtooth shape. However, also in this case, the direction of the linearly polarized light of the incident light 20 is parallel to the direction formed by projecting the liquid crystal molecules 13 onto the arrangement surface of the substrate 42. In this specification and claims, including this case, it is described that the alignment direction of the liquid crystal molecules is substantially parallel to the direction of linearly polarized light.

  FIG. 6 shows an optical deflection apparatus 50 according to the third embodiment of the present invention. The description of this embodiment will be made with respect to parts different from those of the first embodiment, and the rest will be given the same reference numerals as those of the same embodiment, and the description of this embodiment will be replaced with the description of this embodiment. The electric field applying means 51 of this embodiment is disposed between the electrodes 15, and provides resistances having different magnitudes between the electrodes 15, thereby differentiating the electric field strength between the electrodes 15. Elements 52, 53, and 54 are provided in this order in the + Y-axis direction in the coordinate system.

  The resistance values of the resistance elements 52, 53, 54 are in this order from one electrode 15 on the one end side, that is, the position closest to the −Y side in the coordinate system, to the other end side, ie, the coordinate. In the direction toward the one located closest to the + Y side in the system, that is, in the + Y-axis direction, it gradually increases. Specifically, the resistance value of the resistance element 53 is twice the resistance value of the resistance element 52, the resistance value of the resistance element 54 is three times the resistance value of the resistance element 52, and the resistance value gradually increases with an equal difference. It is supposed to be.

  Therefore, as indicated by symbol E in FIG. 7, the electric field between the electrodes 15 gradually increases with an equal difference in the + Y-axis direction, and as shown in FIG. 6, the inclination of the liquid crystal molecules 13 also increases in the + Y-axis direction. Increasing gradually. Thereby, the refractive index distribution of the liquid crystal layer 12 can be approximately changed so as to obtain a desired light deflection direction in the Y-axis direction. In FIG. 7, it is possible to obtain a refractive index distribution as indicated by the symbol n, and the same effect as that of the variable prism can be obtained. The resistance value of the resistance element may be gradually decreased from one electrode located on one end side to the other electrode located on the other end side.

  FIG. 8 shows an optical deflection apparatus 60 according to the fourth embodiment of the present invention. The description of this embodiment will be made with respect to parts different from those of the first embodiment, and the rest will be given the same reference numerals as those of the same embodiment, and the description of this embodiment will be replaced with the description of this embodiment. The light deflection element 61 of this embodiment includes ten electrodes 15 in the Y direction in the coordinate system. The electric field applying means 62 has resistance elements 63a, 63b, 63c, 64a, 64b, 64c, 65a, 65b, 65c that provide resistance between the electrodes 15 in this order in the + Y-axis direction in the coordinate system. Yes.

  The resistance values of the resistance elements 63a, 64a and 65a are equal to each other, the resistance values of the resistance elements 63b, 64b and 65b are equal to each other, and the resistance values of the resistance elements 63c, 64c and 65c are equal to each other. The resistance values of the resistance elements 63b, 64b, 65b are twice the resistance values of the resistance elements 63a, 64a, 65a, and the resistance values of the resistance elements 63c, 64c, 65c are the resistance values of the resistance elements 63a, 64a, 65a. 3 times.

  Therefore, the resistance values of the resistance elements 63a, 63b, and 63c, the resistance values of the resistance elements 64a, 64b, and 64c, and the resistance values of the resistance elements 65a, 65b, and 65c are respectively in this order, Gradually increase in a direction from one end side, that is, the one located closest to the −Y side in the coordinate system to the other end side, ie, the one located closest to the + Y side in the coordinate system, that is, the + Y axis direction. In addition, the resistance values of the resistance elements 63a, 63b, 63c, 64a, 64b, 64c, 65a, 65b, and 65c periodically change in the + Y-axis direction in this order.

  That is, when the resistance element whose resistance value gradually increases in the + Y-axis direction is regarded as one unit, it has three units in the + Y-axis direction. This one unit has the same configuration as that of the third embodiment. Therefore, the electric field strength between each electrode 15 in each unit, its change, direction, and inclination of the liquid crystal molecules 13 are also the third embodiment. It has become the same.

  Therefore, as shown in FIG. 9, the portion of the refractive index distribution of the liquid crystal layer 12 that gradually increases with an equal difference in the + Y-axis direction is periodically repeated three times in the + Y-axis direction. Have gained. Here, as the resistance elements 63a, 63b, 63c, 64a, 64b, 64c, 65a, 65b, and 65c, variable resistors based on electric signals such as an electronic volume can be used, and a potential difference adjuster that adjusts the overall voltage. Is preferably provided. As a method of multiplying the entire voltage, an amplifier such as an operational amplifier can be used.

  According to such a configuration, the light deflection can be caused to function by the diffraction phenomenon. Therefore, all the diffracted light generated from the refractive index distribution can be used as deflected light, so that the light use efficiency is improved. For example, when light is deflected by a refractive index distribution such as a prism, it is ideal to create a completely broad distribution, but this is actually difficult, and the refractive index distribution is stepped. Since light is diffracted from the distribution of light, the light utilization efficiency is deteriorated. However, in this configuration, the light utilization efficiency is improved by using diffraction to achieve the light deflection function. In addition, the resistance value of the resistance element is gradually decreased from one electrode located on one end side to the one located on the other end side, and this is periodically arranged. It is good also as a structure.

  FIG. 10 shows an optical deflection apparatus 70 according to the fifth embodiment of the present invention. The description of this embodiment will be made with respect to parts different from those of the first embodiment, and the rest will be given the same reference numerals as those of the same embodiment, and the description of this embodiment will be replaced with the description of this embodiment. In the light deflecting element 71 of this embodiment, the transparent substrate 72 facing the flat substrate 11 is not flat, and has a surface 73 in which the XY cross section in the coordinate system has a sawtooth shape. Yes. The arrangement surface of the substrate 72 is parallel to the arrangement surface of the substrate 11.

  On the surface of the substrate 11 on the side facing the substrate 72, a planar electrode 74 that is not line-shaped but matched to the shape of the substrate 11 is disposed. Also on the substrate 72, a sawtooth electrode 75 matching the shape of the surface 73 is disposed. On the electrodes 74 and 75, alignment films 76 and 77 corresponding to the shapes of the electrodes 74 and 75 are disposed, respectively. The electric field applying unit 78 applies a voltage to the electrodes 74 and 75. The polarization direction G of the incident light 20 is substantially parallel to the Y-axis direction in the coordinate system.

  As a method for forming the sawtooth shape of the substrate 72, there are a method of etching the substrate 72 by photolithography, a method of directly processing the shape by cutting and grinding, and the like. Further, there is a method in which a transparent plastic material is injection-molded using a mold product having a sawtooth shape formed by such a method, and is transferred to form a substrate 42. The electrodes 74 and 75 have a solid electrode structure formed on the entire surfaces of the substrates 11 and 72, respectively. The electrode material is preferably highly transparent, and commonly used ITO can be used. Further, a sawtooth shape can be used instead of the spacer 16. In this case, it is preferable to perform a process such as etching of an electrode surface to be contacted or providing an insulating film so as not to cause a short circuit.

Also in the optical deflecting device 70 having such a configuration, it is possible to perform an optical deflecting operation by controlling the tilt angle of the liquid crystal director by an electric field using the electric tilt effect.
Here, the light deflection operation will be described with reference to FIG. Since the polarization direction of the incident light 20 to the light deflecting device 70 is constant, the refractive index felt by the incident light 20 depends on the liquid crystal director.

  For example, as shown in FIGS. 11A and 11B, when an electric field of (−E) is applied, the liquid crystal director of the liquid crystal molecules 13 is as shown in FIG. The refractive index felt by the incident light 20 becomes the ordinary light component no, and when the refractive index of the substrate 72 and the refractive index no of the ordinary light component coincide, the outgoing light 25 travels straight. Further, as shown in FIGS. 11C and 11D, when an electric field of (+ E) is applied, the liquid crystal director of the liquid crystal molecules 13 becomes as shown in FIG. The refractive index felt by 20 becomes an extraordinary light component ne. When the refractive index ne of the substrate 72 and the refractive index ne of the extraordinary light component do not match, the outgoing light 25 is deflected in the + Y-axis direction in the coordinate system. Here, the refractive index of the substrate 72 and the refractive index of the ordinary light component are matched, but when the refractive index of the extraordinary light component is matched with the refractive index of the substrate 72 and the refractive index no of the ordinary light component is felt. It is good also as a structure which brings about a deflection | deviation effect | action.

  Therefore, by controlling the electric field, the refractive index of the liquid crystal layer 12 sensed by the incident light 20 is changed by tilting the liquid crystal director in the initial horizontal alignment, that is, the homogeneous alignment, in the alignment plane of the substrate 72 by the electric tilt effect. Thus, an optical deflection operation of linearly polarized light can be performed. This is because the direction in which the liquid crystal molecules 13 are inclined is always parallel to the arrangement surfaces of the substrates 11 and 72, so that the direction of the linearly polarized light of the incident light 20 is vertical even if it is parallel to the alignment direction of the liquid crystal molecules 13. However, this is because the average refractive index felt by the incident light 20 changes due to electric field control.

  The light deflection direction can be set by the pitch, depth, etc. of the sawtooth shape, and in such a configuration, the light deflection operation in the binary direction is performed. Although the driving voltage of the liquid crystal layer 12 depends on the cell gap, since the gap of the liquid crystal layer 12 is relatively narrow in the optical deflection element 71, an optical deflection operation can be realized with low voltage driving. Since the smectic A layer has spontaneous polarization and exhibits very high responsiveness, an optical deflecting device 71 capable of high-speed analog optical deflection operation is realized. The sawtooth shape may be provided on at least one of the substrates 11 and 72, and may be formed on the substrate 11 or may be formed on both the substrates 11 and 72.

The optical deflection apparatus according to the first to fifth embodiments of the present invention has been described above.
Here, as described in the description of the electroclinic effect, the electroclinic effect is a phenomenon that occurs in the temperature region where the smectic A phase transitions to the smectic C phase. Outside this temperature range, the light deflection amount changes, There is a possibility that a defect such as not showing the deflection function may occur.

  Therefore, as shown in FIG. 12, the optical deflection apparatus 30 according to the embodiment of the present invention is provided with a temperature detection means 26 for detecting the temperature of the optical deflection element, and an appropriate temperature range in which an electroclinic effect can be obtained. It is supposed to detect the operating temperature. In addition, by providing a stop means (not shown) for stopping the operation when the temperature is outside the appropriate temperature range, it is possible to prevent damage due to temperature rise.

  Although not shown, the temperature detection means 26 includes a temperature sensor as a temperature detection element and a temperature measurement circuit as a temperature measurement means. As the temperature detection element, for example, a thermistor, a thermocouple, or the like is used. be able to. In particular, thermocouples have a large thermoelectromotive force, small variations in characteristics, and are compatible. In addition, it has features such as being stable against heat and having a long life, and is highly reliable. As the material, for example, K (chromel-alumel), J (iron-constantan), T (copper-constantan), E (chromel-constantan), N (nycrosyl-nycyl) or JIS standard defined in the JIS standard. External (nickel-nickel 18% molybdenum), (tungsten 5% rhenium-tungsten 26% rhenium), or the like can be used.

In order to further improve the accuracy of temperature detection, it is preferable to install temperature detection means in the optical path. However, it is preferable to use a material made of a transparent resistor in order to prevent temperature detection means installed in the optical path from blocking incident light and reducing the overall light utilization efficiency. As this resistor, SnO ₂ or IN ₂ O ₃ can be used. As the formation method, it can be directly formed on the substrate constituting the optical deflection element by a vacuum deposition method, a sputtering method or the like. The temperature can be detected from the temperature characteristic of the resistance value of such a resistor.

  The optical deflection device 30 includes not only the temperature detection unit 26 but also a temperature control unit 27 that controls the temperature of the optical deflection element 21 based on the temperature detected by the temperature detection unit 26. The temperature control means 27 is provided integrally with the light deflection element 21 at both ends of the light deflection element 21 outside the light deflection element 21 and the drive control means 19 as a temperature control circuit such as a CPU connected to the temperature detection means 26. And a pair of heaters 28 as heating means whose energization is controlled by the drive control means 19, and a light transmission window 29 that is disposed between the heaters 28 and transmits the incident light 20. . However, the heating means provided in the temperature control means 27 uses Joule heat obtained by forming a resistance wire in contact with the inside or the surface of the optical deflecting element 21 and causing a current to flow in order to reduce the size. Is preferred. Although not shown in the drawing, a Peltier element or the like is provided as a cooling means, that is, a cooling source, and can be driven by the drive control means 19.

  By having the temperature detecting means 26, the optical deflecting device 30 can detect whether the temperature of the optical deflecting element 21 is always within an appropriate temperature range in which a stable light deflection amount can be obtained. When the temperature of the light deflection element 21 is within the proper temperature range by providing the stopping means as described above, the operation is disabled when the temperature is outside the set temperature range determined based on the proper temperature range. It is possible to prevent problems that occur when the user is outside.

  Further, since the optical deflection device 30 includes the temperature control means 27 in addition to the temperature detection means 26, in the optical deflection device 30, the temperature of the optical deflection element 21 is always stable without using the stopping means described above. It can be controlled so that the amount of light deflection is within an appropriate temperature range. That is, a stable light deflection amount, in other words, a constant light deflection amount can be obtained. Here, since the temperature characteristic of the liquid crystal material, that is, the phase transition point varies depending on the material, the appropriate temperature range is appropriately set depending on the material used. The optical deflecting device 30 is according to the first embodiment of the present invention. Similarly, in the optical deflecting device according to the other embodiments, the temperature detecting means and the temperature controlling means described here are also used. Etc. can be provided.

  These light deflection devices are mounted on an image display device such as an electronic display device such as a projection display or a head-mounted display, and a transmissive liquid crystal light valve, a reflective liquid crystal light valve, a DMD element, etc. provided in the image display device. This is used to apparently increase the number of pixels of the image display element. Such an image display apparatus will be described below.

  As shown in FIG. 13, the image display device 80 includes a light source 81 that can be turned on and off at high speed, a light source driving unit 82 that turns on and off the light source 81, a combination of a white lamp and a shutter, and a light source 81. An illumination device 83 for uniforming the emitted light, an image display element 84 in which a plurality of pixels are two-dimensionally arranged to spatially modulate and emit uniform illumination light incident from the illumination device 83, and image display A display driving unit 85 that drives the element 84 to display a predetermined image and a reduction optical element 86 that reduces a display image by the image display element 84 are provided.

  The image display device 80 also controls any one of the above-described light deflecting devices 1 that receive light from the reduction optical element 86 and deflect the light, and a voltage applied to the light deflecting device 1. Light deflection voltage control means 87, a projection lens 88 that enlarges the light deflected by the light deflection apparatus 1 to form image light, a screen 89 as an optical member on which light transmitted through the projection lens 88 is projected, and a light source drive An image display control circuit 90 as a control means for controlling the means 82, the display drive means 85, and the light deflection voltage control means 87 to increase the apparent number of pixels of the image observed by the screen 89; ing.

  The light source 81 may be any LED light source, laser light source, white lamp light source combined with a shutter, etc., as long as it can turn on or off light of white or any color at high speed. ON / OFF of the light source 81 by the light source driving means 82 is controlled by the image display drive control circuit 90, and the light source 81 illuminates the image display element 84. The illumination device 83 includes the diffusion plate 91, the condenser lens 92, and the like, but a fly-eye lens or the like can be used. The image display element 84 is capable of controlling light by being driven by the display driving means 85 in accordance with image information from the image display drive control circuit 90, and uses a transmissive liquid crystal light valve combined with a color filter. However, the combination of the color filters is arbitrary, and a reflective liquid crystal light valve, a DMD element, or the like can be used instead of the transmissive liquid crystal light valve.

  The reduction optical element 86 includes a microlens, a collimator lens, and the like. The reduction amount is preferably 1 / integer of the pixel pitch. The arrangement position of the light deflection apparatus 1 is a defocus position of a pixel displayed from the image display apparatus between the image display element 84 and the screen 89, and is configured so as not to deteriorate the resolution of the display image. The light deflection apparatus 1 is arranged behind the image display element 84 and the reduction optical element 86, and is applied by one of the above-described electric field application means by the light deflection voltage control means 87 controlled by the image display control circuit 90. Is controlled to shift the image light by an arbitrary distance in the pixel arrangement direction.

  The amount of shift of light by the optical deflecting device 1 is preferably an integral number of the pixel pitch, similarly to the reduction amount, and the shifted pixels do not overlap when the shift amount and the reduction amount are equal. Therefore, the resolution is not reduced due to the pixel shift effect. In addition, if the shift amount and the reduction amount are different, the shifted pixels overlap each other or the resolution is reduced by spreading between the pixels. However, if there is no problem with the display image, the shift amount and the reduction amount are sufficient. May not be equal. When performing image multiplication twice as much as the pixel arrangement direction, the pixel pitch is set to 1/2. When performing pixel multiplication of 3 times, the pixel pitch is set to 1/3. When the shift amount increases due to the configuration of the optical path deflection voltage control means, the shift amount and the pixel reduction amount may be set to a distance of (integer multiple + 1 / integer) of the pixel pitch.

  In any case, under the control of the image display control circuit 90, the image display element 84 is driven by the image signals of a plurality of subfields obtained by temporally dividing the image field corresponding to the pixel shift positions, and each subfield is controlled. Further, the optical path between the image display element 84 and the screen 89 is deflected by the optical deflecting device 1. Therefore, the light emitted from the light source 81 by the control by the image display control circuit 90 becomes illumination light that is made uniform by the diffusion plate 91, and the image display element 84 is critically illuminated by the condenser lens 92. The spatial light-modulated illumination light is magnified by the projection lens 88 and projected onto the screen 89 as image light, and the image projected onto the screen 89 is observed with an apparent number of pixels increased.

  Therefore, a high-definition and high-contrast image that is higher than the resolution of the used image display element 84 can be displayed. For example, as shown in FIG. 14, by setting the shift amount to I with respect to the pixel pitch H of the image display element 84, the apparent pixel pitch on the screen 89 is J, and the apparent pixel increase is increased. Since the doubling effect is obtained, a high-definition and high-contrast image that is higher than the resolution of the used image display element 84 can be displayed. Further, since the optical deflection apparatus 1 using smectic A-phase liquid crystal is used, the response speed of the optical deflection operation is very fast. Therefore, flicker, flicker, etc., which are problematic when performing optical deflection with a slow response speed, are caused. It is a high-definition, high-resolution, high-quality image display device that does not occur and has little contrast reduction.

  The image display device 80 can display a color image by using a transmissive liquid crystal light valve in which a white lamp is used as the light source 81 and a color filter is combined with the image display element 84. Full-color image display can also be performed by a field sequential method in which a single-plate image display element is illuminated with three primary colors in time sequence. At this time, time-sequential three primary color lights may be generated by combining a white lamp light source and a rotating color filter.

  FIG. 15 shows an example of the arrangement of optical deflection elements applicable to the image display device 80. The light deflection element 93 is provided in the light deflection apparatus 1. The optical deflection element 93 and the optical deflection apparatus 1 correspond to the optical deflection element 41 and the optical deflection apparatus 40 according to the second embodiment of the present invention shown in FIG. The sawtooth shape of the light deflection element 93 is formed in an array so that the ridge lines parallel to the direction indicated by the arrow K are aligned in the left-right direction on the paper surface in FIG. Light 94 emitted from the image display element 84 is linearly polarized light indicated by an arrow L and polarized in the left-right direction on the paper surface in FIG. The K direction corresponds to the Y-axis direction of the coordinate system in FIG. 5, and the L direction corresponds to the Z-axis direction of the coordinate system in FIG.

  Therefore, in the image display device provided with the light deflecting element 93, as shown by the arrow M, the entire light 94 can be shifted in the horizontal direction of the paper surface in FIG. An image can be obtained. In this example, the image is observed with the number of pixels increased in one direction indicated by an arrow M. The M direction corresponds to the Z-axis direction of the coordinate system in FIG. By using the light deflection element 93 provided with such a light-shielding portion, effects such as high-definition and low contrast reduction as described above can be obtained in the horizontal shift of the screen, that is, the shift in the M direction orthogonal to the K direction. An image display device is achieved.

  The various optical deflection devices described above that can be mounted on such an image display device are also mounted on an optical writing device using a light emitter array or the like as an image forming engine, and are provided in such a light emitter array at predetermined intervals. It is used to make the interval between the irradiation positions of the light emitted from the arranged light emitting members smaller than the predetermined interval. Further, such an optical polarization device is mounted on an image forming apparatus such as a copying machine, a facsimile, a printer, or the like using these optical writing devices, or a complex machine thereof, such as an MFP, while being mounted on such an optical writing device. Is possible. Such an optical writing apparatus will be described below.

  FIG. 16 shows a case where such an optical writing device 95 is mounted on such an image forming apparatus, and the recording body α corresponds to an image carrier such as a photoconductor provided in such an image forming apparatus. . The optical writing device 95 is an optical writing device using a polygon mirror or the like that is generally mounted in such an image forming apparatus, but the configuration other than the configuration shown in FIG. 16 such as a polygon mirror is the essence of the present invention. The description thereof is omitted because it does not significantly affect For the same reason, the description of the configuration of the image forming apparatus is also omitted.

  As shown in FIG. 16, the optical writing device 95 includes a light emitter array having a plurality of light emitters 96 as light emitting members arranged in the R direction at a predetermined interval, that is, a pixel pitch Q. 97 and the light emitting array 96 arranged near the light emitter array 97 to condense the light 45 emitted and emitted from the light emitters 96 to change the luminance distribution of the light emission spots, thereby changing the writing spot shape on the recording material α. A microlens array (not shown) for controlling the light, a lens (not shown) for focusing the light 45 transmitted through the microlens array on the recording body α, and the arrangement direction R of the light emitter 96 with the light 45 transmitted through the lens. And optical path shifting means 2 that can be electrically shifted in a substantially parallel S direction.

  The optical path shifting means 2 is disposed on the optical path of the light 45 from the light emitter array 97 toward the recording body α, and although not shown, any one of the above-described optical deflection devices is connected to the light emitter 96. Corresponding to each, it has the state arrange | positioned by the space | interval Q in the R direction. As the light emitter 96, a light source such as an LED, that is, a light emitting diode, or a laser diode, that is, a semiconductor laser, can be used. be able to.

  In order to perform high-definition pixel exposure on the recording medium α, the light emitter 96 preferably has a small area and high directivity of the emitted light 45. Further, the wavelength of the light 45 emitted from the light emitter 96 can be designed based on the characteristics of the light emitting material and the filter, and is appropriately set according to the spectral sensitivity of the recording body α on which writing is performed by the writing device 95. The light emitter array 97 has a plurality of these light emitters 96 arranged one-dimensionally or two-dimensionally.

  A liquid crystal microlens array can be used as the microlens array, and the exposure spot size on the recording medium α may be variable by a variable focus function using an electric field. A spherical lens, an aspherical lens, a gradient index lens array, or the like can be used as a lens for focusing the light emitted from the light emitter 96 on the recording body α. A gradient index lens array that can shorten the distance between image planes, that is, a SELFOC lens array is preferable. A liquid crystal layer may be provided on a part of the lens to form a liquid crystal lens, and the exposure spot size on the recording medium α may be variable by a variable focus function using an electric field.

  Here, if the pixel pitch Q of the light emitters 96, that is, the arrangement pitch Q is P μm, the optical path is shifted by a distance P / 2 μm in the arrangement direction R of the light emitters 96 on the recording body α by the optical path shift means 2. By shifting at a high speed, it becomes possible to perform exposure with a pixel density that is twice as high as interpolation between pixels.

  In the optical writing device 95 having such a configuration, the light emitters 96 arranged at a predetermined pitch Q in the light emitter array 97 are driven according to an image signal corresponding to an image to be formed in the image forming apparatus, and the light emitters 96. The light is emitted from. The light 45 emitted from the light emitter 96 is converged on the recording body α by transmitting through a lens (not shown), and then the exposure spot on the recording body α is controlled by transmitting through the microlens array. The optical path of the light 45 is shifted in the R direction by passing through the optical path shifting means 2 and either the position of the arrow indicated by the broken line or the position of the arrow indicated by the chain line on the recording medium α. As a result, the recording body α is exposed.

  However, since the shift by the optical path shift means 2 is performed while the polarity of the electric field is switched at high speed by the switching operation, the position of the arrow indicated by the broken line or the position indicated by the chain line on the recording medium α is substantially in a straight line. Located in. Such a high-speed switching is realized by the advantage that the optical deflection device provided in the optical path shift means 2 uses smectic A-phase liquid crystal and the response speed of the optical deflection operation is very fast. By the optical path shifting means 2 that exhibits such an optical path shifting function, the light 45 from the light emitter array 97 moves relative to the recording body α, so that two-dimensional image information is exposed on the recording body α. Is done.

  With respect to the exposure pitch T, the optical writing device 95 controls the optical deflection device provided in the optical path shifting means 2 to drive the electric field to control the light 45 emitted from the light emitter 96 toward the writing position on the recording material α. , Thereby making the light interval T at the writing position on the recording body α smaller than the pixel pitch Q, so that the recording body α is irradiated with light that is complemented between the pixel pitches Q. Therefore, high-resolution image exposure is possible even when a low-resolution light emitter array is used.

  Since the optical path shift means 2 has a light deflecting device corresponding to each light emitter 96 provided in the light emitter array 97, the position of the light emitted from each light emitter 96 is shifted. In addition, the pixel pitch can be complemented at equal intervals by driving control of the optical deflector. That is, it is possible to suppress the influence due to deterioration with time and the like, and stable and high-resolution image exposure is always possible.

  Hereinafter, embodiments of the optical deflection apparatus, the image display apparatus, and the optical writing apparatus corresponding to any of the optical deflection apparatus, the image display apparatus, and the optical writing apparatus of the above-described form will be described. However, in order to clarify the advantages of such an optical deflecting device, an image display device, and an optical writing device, an example of a conventional optical deflecting device will be described as a comparative example before the description thereof, and thereafter each example will be described. explain.

(Comparative example)
In this example, unlike the optical deflecting device according to the present invention, an electrode is disposed at a portion where a spacer is disposed in the optical deflecting device according to the present invention. This light deflection apparatus is a polyimide liquid crystal horizontal alignment agent applied to the surface of a glass substrate having a size of 3 cm × 4 cm and a thickness of 1.1 mm by spin coating, and is baked in a high-temperature bath at 120 ° C. An alignment film is formed. Thereafter, rubbing treatment was performed to regulate the alignment direction of the liquid crystal to a certain direction.

  Two glass substrates having a thickness of 10 μm, a width of 1 mm, and a length of 3 cm were placed in parallel with the rubbing direction, and two glass substrates were bonded together with the alignment film as the inner surface as a spacer. The two aluminum electrode sheets were parallel and the distance between them was 2 mm. While the substrate was heated, a ferroelectric liquid crystal having a smectic AC phase transition was injected between the two substrates by a capillary method, and after cooling, sealed with a UV adhesive.

  A mask pattern having a line / space width of 5 μm was provided on the incident surface side of the light deflection element thus fabricated, and illumination was performed with linearly polarized light collimated from the mask pattern side. The direction of linearly polarized light was set to be the same as the longitudinal direction of the aluminum electrode sheet. The light transmitted through the mask pattern was observed with a microscope through the two aluminum electrode sheets of the light deflection element. When a rectangular voltage was applied using a pulse generator and high-speed power amplifier, the mask pattern was observed to shift in parallel.

  However, the shift amount was different near the electrode and near the center between the electrodes. This seems to be because the electric field strength varies depending on the location. Since the electrode is a spacer, the distance between the electrodes is large, the electric field near the electrodes is strong, and the electric field is weak near the center between the electrodes, so the inclination of the liquid crystal molecules whose inclination depends on the strength of the electric field is Because it is large near the electrodes and small near the center between the electrodes, the amount of light shift is sufficient near the electrodes, whereas the light shift is considered insufficient at the center between the electrodes. is there.

(Example 1)
This example corresponds to the light deflection apparatus 50 according to the third embodiment. This optical deflecting device is an electrode having a line width of 10 μm, a line pitch of 100 μm, and a line length of 2 cm by ITO deposition on the surface of a glass substrate having a size of 3 cm × 4 cm and a thickness of 1.1 mm. 20 ITO electrode lines are formed. One end of the line was made larger in width and pitch to get contact from the power source. A polyimide-based liquid crystal horizontal alignment agent was applied by spin coating on the ITO electrode line and on a substrate without electrodes, and was baked in a high-temperature bath at 120 ° C. Thereafter, rubbing treatment was performed in the line electrode line direction so that the liquid crystal molecules were horizontally aligned in a certain direction.

  As the spacer between the substrates, two mylar sheets having a thickness of 10 μm were used, and two glass substrates with and without a line electrode were bonded together with the alignment film as the inner surface. The two mylar sheets were parallel and the distance between them was 2 mm between the line electrodes. While the substrate was heated, a ferroelectric liquid crystal having a smectic AC phase transition was injected between the two substrates by a capillary method, and after cooling, sealed with a UV adhesive. Thus, an optical path deflecting element similar to the optical deflecting element 21 provided in the optical deflecting device 50 according to the third embodiment was produced.

  The prepared optical deflecting element was placed under a cross nicol, the temperature was adjusted, and the tilt angle and response speed due to the electroclinic effect were measured. At a measurement temperature of 29 ° C., the tilt angle was 8 when the electric field was 5 V / μm. The inclination angle was 12 ° when the electric field was 15 V / μm, and the inclination angle was 13 ° when the electric field was 25 V / μm. At a measurement temperature of 38 ° C., the inclination angle is 3 ° when the electric field is 5 V / μm, the inclination angle is 6.5 ° when the electric field is 15 V / μm, and the inclination angle is 10 ° when the electric field is 25 V / μm. Yes, the tilt angle depended on temperature and electric field. The response speed was a fast response of 50 μsec or less.

  In order to confirm the light deflection operation, a mask pattern having a line / space width of 5 μm was provided on the light incident surface side of the produced light deflection element, and illumination was performed with linearly polarized light through this mask pattern. The light transmitted through the mask pattern was observed with a microscope through the ITO electrode line of the light deflection element. The mask pattern was observed as it was when no electric field was applied. Here, the resistance elements having different resistance values are connected to one end of the 20 ITO electrode lines, and the resistance values are different from each other so that the electric field intensity on the surface of the optical deflection element becomes stepwise. The electrodes were connected in a similar manner to the electric field applying means 51 provided in the optical deflecting device 50 according to the embodiment. When a square wave voltage of ± 200 V was applied to both ends of the series resistance element by using a pulse generator and a high-speed power amplifier, it was confirmed that the mask pattern was shifted near the center of the element. When the observation position was changed, the shift amount unevenness observed in the comparative example was not confirmed, and a uniform shift was obtained. This is considered to be because the electric field was stably applied by using the line electrode. Further, the shift amount changed depending on the voltage value.

(Example 2)
This example is for confirming the relationship between the deflection direction of the incident linearly polarized light and the alignment direction of the initial alignment of the liquid crystal molecules with respect to the shift amount. That is, in this example, as in Example 1, the fabrication of the light deflection element and the confirmation of the light deflection operation were performed, and at that time, the direction of the incident linearly polarized light was rotated and the light deflection operation was observed. As a result, when the linearly polarized light direction coincides with the rubbing direction, the optical path shift amount becomes the largest, and when it is orthogonal to the rubbing direction, no light deflection operation has been confirmed. This indicates that the light deflection operation is performed efficiently when the polarization direction of the incident light coincides with the initial alignment of the liquid crystal molecules.

(Example 3)
This example corresponds to the optical deflecting device 70 according to the fifth exemplary embodiment. This optical deflecting device is a sawtooth surface after forming a sawtooth shape having an inclination angle of about 1 ° and a pitch of 100 μm to an area of 1 cm × 1 cm by dry etching on a glass substrate having a size of 3 cm × 4 cm and a thickness of 1 mm. An ITO electrode was sputtered to a thickness of 1500 mm. Next, a polyimide alignment agent was applied to a thickness of about 800 mm, and the substrate surface was subjected to alignment treatment by a rubbing method under the condition that the stable direction in the homogeneous direction was perpendicular to the inclined direction of the inclined region. That is, the orientation process was performed in the direction of the saw-tooth marking.

  Using a glass substrate with an ITO electrode having a smooth surface as a counter substrate, bonding was performed using an adhesive in which beads were mixed so that a portion with a small liquid crystal layer thickness was 3 μm. Thereafter, while the substrate was heated, a ferroelectric liquid crystal having a smectic AC phase transition was injected between the two substrates by a capillary method, and after cooling, sealed with a UV adhesive. In this manner, an optical path deflecting element similar to the optical deflecting element 71 provided in the optical deflecting device 70 according to the fifth embodiment was produced. The tilt angle and response speed characteristics of the manufactured light deflection element were almost the same as those in Example 1.

  Here, a voltage was applied to the produced optical deflection element to drive it. The applied voltage was a square wave voltage of ± 20 V using a function generator. The incident light to the element was white laser light having a diameter of about 1 mm and passed through a wavelength selection filter (588 nm) to set the wavelength of the incident light. Further, a polarizing plate was installed between the element and the laser device, the direction of linearly polarized light was set to be inclined by 15 ° from the sawtooth direction, and was incident on the sawtooth array position. The element was operated in this way, and the transmitted light passing through the element was observed with a CCD camera. The CCD camera was installed at a distance of about 1 m from the device. As a result, it was confirmed that the transmitted light was deflected by switching the voltage. In this example, since the substrate interval was small, the voltage could be reduced as compared with Example 1.

Example 4
The present embodiment corresponds to the light deflection element 41 provided in the light deflection apparatus 40 according to the second embodiment with respect to the light deflection element, and the electric field application means according to the third embodiment. This corresponds to the electric field applying means 51 provided in the optical deflection apparatus 50 according to the above. This optical deflecting device was manufactured by dry etching in the same manner as in Example 3 for the sawtooth substrate provided in the optical deflecting element. An ITO line electrode similar to that in Example 1 was formed on a smooth substrate, which is another substrate facing the sawtooth substrate.

  A polyimide alignment agent was applied to the two substrate surfaces and subjected to a rubbing treatment. The rubbing direction was the line direction of the line electrodes, and the substrates were bonded using an adhesive mixed with beads having a size of 3 μm so that the surfaces subjected to the alignment treatment were opposed to each other. At that time, the bonding was performed so that the saw-toothed marking direction and the line direction of the line electrode were parallel. After bonding, a ferroelectric liquid crystal having a smectic A-C phase transition was injected between the two substrates with a capillary method while the substrates were heated. After cooling, the substrates were sealed with a UV adhesive. Thus, an optical path deflecting element similar to the optical deflecting element 41 provided in the optical deflecting device 40 according to the second embodiment was produced.

  In the same manner as in Example 1, a mask pattern having a line / space width of 5 μm was provided on the incident surface side of the optical path deflecting element, and illumination was performed with linearly polarized light through this mask pattern. The light transmitted through the mask pattern was observed with a microscope through the vicinity of the center between the ITO electrode lines of the optical path deflecting element. The mask pattern was observed as it was when no electric field was applied. Here, the resistance elements having different resistance values are connected to one end of the 20 ITO electrode lines, and the resistance values are different from each other so that the electric field intensity on the surface of the optical deflection element becomes stepwise. The electrodes were connected in a similar manner to the electric field applying means 51 provided in the optical deflecting device 50 according to the embodiment. When a square wave voltage of ± 200 V was applied to both ends of the series resistance element by using a pulse generator and a high-speed power amplifier, it was confirmed that the mask pattern was shifted near the center of the element. This shift amount is larger than that of the first embodiment because the sawtooth substrate is used in this embodiment.

(Example 5)
This example corresponds to the optical deflecting device 60 according to the fourth exemplary embodiment. This optical deflection apparatus was manufactured in the same manner as in Example 1 with respect to the optical deflection element. Here, the light deflection according to the fourth embodiment shown in FIG. 8 is performed so that a conducting wire is connected to one end of the 20 ITO electrode lines, and the electric field intensity on the surface of the light deflection element becomes stepwise and periodic. In a manner similar to the electric field applying means 62 provided in the device 60, a series resistor was connected between the electrodes so that the resistance value of each resistive element was periodic.

  In this state, when a rectangular wave voltage was applied to both ends of the series resistance element using a pulse generator and a high-speed power amplifier, it was confirmed that the mask pattern was shifted near the center of the element. The shift amount at this time almost coincided with the value calculated from the pitch of the resistance values set periodically, and the light deflection operation was due to diffraction. When the light deflection operation was performed as in the present embodiment, the observed mask pattern was clear with less ghost compared to the first embodiment. This can be presumed to be because all of the light deflection action is deflected by diffraction.

(Example 6)
In this example, an optical deflecting element manufactured in the same manner as in Example 1 corresponding to the optical deflecting element 21 provided in the optical deflecting device 50 according to the third embodiment is described with reference to FIG. A temperature control device corresponding to the temperature detection means 26 and the temperature control means 27 is attached. The ferroelectric liquid crystal used here exhibits an electroclinic effect in the range of about 25 ° C. to 40 ° C., and at a measurement temperature of 29 ° C., the electric field is 5 V / μm, the tilt angle is 8 °, and the electric field is 15 V. The inclination angle was 12 ° at / μm, and the inclination angle was 13 ° at an electric field of 25 V / μm. At a measurement temperature of 38 ° C., the inclination angle is 3 ° when the electric field is 5 V / μm, the inclination angle is 6.5 ° when the electric field is 15 V / μm, and the inclination angle when the electric field is 25 V / μm. : 10 °.

  The temperature control device for the optical deflection element includes a heater corresponding to the temperature control means 27 and a temperature control circuit corresponding to the drive control means 19 and a temperature detection element corresponding to the temperature detection means 26. And a temperature measuring circuit as a temperature measuring means. A liquid crystal cell heating device TH600 manufactured by LINKAM and a digital thermometer manufactured by Anritsu Keiki were used as temperature control devices. Similar to the configuration described with reference to FIG. 12, there is a transmission window between the heaters so that the optical path is not blocked. In the example described with reference to FIG. 12, since the heater is in contact with one surface of the light deflection element, a temperature difference occurs between the front surface and the back surface of the light deflection element. In this embodiment, temperature sensors are arranged on both surfaces of the element. The average value of the two was set to be detected as the temperature of the light deflection element.

  Here, when the set temperature of the temperature control device was set to a temperature range of 50 ° C. to 60 ° C. that does not show the electroclinic effect, the light deflection operation could not be confirmed even when driven by voltage application in the same manner as in Example 1. . Therefore, when the set temperature of the temperature control device was controlled in the range of 25 ° C. to 40 ° C. and driven by voltage application, a stable optical path shift amount could be controlled.

(Example 7)
In this example, an optical deflection element manufactured in the same manner as in Example 1 and corresponding to the optical deflection element 21 provided in the optical deflection apparatus 50 according to the third embodiment is used. A control device is attached, and two sets of these are used to constitute an optical deflection device, which is applied to an image display device corresponding to the image display device 80 shown in FIG. This image display apparatus uses a 0.9 inch diagonal XGA (1024 × 768 dots) polysilicon TFT liquid crystal light valve as an image display element. The pixel pitch of such an image display element is about 18 μm both vertically and horizontally. The aperture ratio of the pixel is about 50%. Further, a microlens array is provided on the light source side of the image display element to increase the collection rate of illumination light.

  In this embodiment, an RGB three-color LED light source is used as a light source, and a so-called field sequential method is adopted in which color display is performed by switching the color of light applied to the one liquid crystal panel at a high speed. In this embodiment, it is assumed that the frame frequency of image display is 60 Hz, and the subfield frequency for pixel multiplication by 4 times by pixel shift is 240 times, which is 4 times. In order to further divide one subframe into three colors, an image corresponding to each color is switched at 720 Hz. A full color image can be seen by an observer by turning ON / OFF the LED light source of the corresponding color in accordance with the display timing of each color image on the liquid crystal panel.

  The basic configuration of each optical deflection element is the same as that of Example 1, but the effective area of the line electrode is 18 mm. A transparent film heater (Teijin T-COAT type F) was used as a heater. The transparent heater surface was placed in close contact with the light deflection element substrate. The size of the glass substrate of the light deflection element and the size of the transparent heater were 3 cm × 4 cm. The surface resistance value of the transparent heater was 500Ω / □, and when a voltage of 15 V was applied, the surface of the heater was heated at 12 ° C. per minute.

  Two sets of elements with heaters are used, the incident side is the first light deflection element, the emission side is the second light deflection element, the directions of the transparent electrode lines are orthogonal, and the arrangement direction of the pixels of the image display element Arranged to match. In this embodiment, the light emitted from the liquid crystal light valve is already linearly polarized light, and the polarization direction thereof is arranged to coincide with the optical path deflection direction of the first optical path deflecting element. In order to ensure the degree of polarization, a linearly polarizing plate was provided as a polarization direction control means on the incident surface side of the optical path deflecting element. As a result, the generation of noise light that goes straight without being deflected by the first light deflection element can be prevented.

  Further, a polarization plane rotating element is provided between the first optical path deflecting element and the second optical path deflecting element. The polarization plane rotating element is obtained by spin-coating a polyimide alignment material on a thin glass substrate (3 cm × 4 cm, thickness 0.15 mm) to form an alignment film of about 0.1 μm. Thereafter, a rubbing treatment was performed. An empty cell was produced by sandwiching an 8 μm thick spacer between the two glass substrates and pasting the upper and lower substrates so that the rubbing directions were orthogonal. Into this cell, a nematic liquid crystal having a positive dielectric anisotropy and an appropriate amount of a chiral material mixed was injected under normal pressure to produce a TN liquid crystal cell in which the orientation of liquid crystal molecules was twisted by 90 degrees. Since this cell is not provided with an electrode, it functions as a simple polarization rotation element.

  The polarizing plate of light emitted from the first optical path deflecting element and the incident surface of the polarization rotating element were arranged so as to be sandwiched between the two optical path deflecting means so that the rubbing directions of the incident surface of the polarization rotating element coincide. The polarization plane of the outgoing light from the first optical path deflection element is rotated by 90 degrees by the polarization plane rotation element, and coincides with the deflection direction of the second optical path deflection element. An optical deflecting device including a first optical deflecting element, a polarization plane rotating element, and a second optical deflecting element was constructed and installed immediately after the liquid crystal light valve.

  The temperature of the optical deflection element is set to 30 degrees, the voltage of the rectangular wave voltage for driving the optical deflection element is ± 5 kV (average electric field is ± 280 V / mm), the frequency is 120 Hz, and the vertical and horizontal phases of the two sheets are The drive timing was set so as to shift the pixel in four directions by shifting by 90 degrees. By rewriting the subfield image to be displayed on the final image display device at 240 Hz, a high-definition image in which the apparent number of pixels was multiplied by 4 in two vertical and horizontal directions could be displayed.

(Example 8)
In this example, an optical deflecting element produced in the same manner as in Example 1 corresponding to the optical deflecting element 21 provided in the optical deflecting device 50 according to the third embodiment was described with reference to FIG. This is applied to an optical writing device corresponding to the optical writing device 95. The light emitter array is an array of LEDs as light emitters, with a pixel pitch of 30 μm. The optical writing device has a microlens array for focusing light on a recording medium. An image was exposed on the recording medium using the optical writing apparatus having such a configuration. An image exposed without driving the light deflection element had a pitch similar to the pixel pitch of the light emitter array. When the light deflection element was driven and exposed, the recorded image was finer than the pixel pitch of the light emitter array, and was high definition.

  Although various configuration examples to which the present invention is applied have been described above, the electric field forming means changes at least one of the intensity and direction of the electric field so that a desired electric field for obtaining a desired deflection can be formed. It can be made. In addition, as described in the fourth embodiment, an electric field is formed by an electric field forming unit in which a resistance element is arranged in a manner in which a resistance value gradually increases or decreases on an optical deflection element in which at least one of the substrates has a sawtooth shape. Alternatively, a configuration may be adopted in which an electric field is formed by an electric field forming means in which a resistance element is arranged in such a manner that the resistance value periodically changes in an optical deflection element in which at least one of the substrates has a sawtooth shape. Further, as described in the seventh embodiment, the light deflection apparatus may include a plurality of light deflection elements. In the case where a plurality of light deflecting elements are provided as in the example described with reference to the seventh embodiment and FIG. 16, a power source for forming an electric field is used in common. Parts can be shared.

It is a figure which shows the outline of the optical deflection apparatus concerning the 1st Embodiment of this invention. FIG. 2 is a plan view, a front view, and a side view of the light deflection element shown in FIG. 1. It is a model figure for demonstrating a meter effect. It is a top view which shows the mode of the liquid crystal molecule when an electric field is applied to the optical deflection element shown in FIG. It is the outline of the optical deflection apparatus concerning the 2nd Embodiment of this invention, its top view, and a side view. It is a figure which shows the outline of the optical deflection apparatus concerning the 3rd Embodiment of this invention. FIG. 7 is a model diagram of electric field strength and refractive index distribution in the optical deflection element shown in FIG. 6. It is a figure which shows the outline of the optical deflection apparatus concerning the 4th Embodiment of this invention. FIG. 9 is a model diagram of a refractive index distribution in the optical deflection element shown in FIG. 8. It is a figure which shows the outline of the optical deflection apparatus concerning the 5th Embodiment of this invention. It is a top view which shows the mode of the liquid crystal molecule at the time of applying an electric field to the optical deflection element shown in FIG. It is a conceptual diagram which shows the structure which arrange | positioned the temperature detection means and the temperature control means to the optical deflection | deviation apparatus shown in FIG. It is a conceptual diagram which shows the structure of the image display apparatus provided with the optical deflection apparatus to which this invention is applied. It is a conceptual diagram which shows the mode of the image displayed by the image display apparatus shown in FIG. In the image display apparatus shown in FIG. 13, in which an optical deflection apparatus having an optical deflection element having a sawtooth substrate is mounted, the direction and deflection of linear polarization of light by the optical deflection element It is a conceptual diagram which shows a direction. It is a conceptual diagram which shows the structure of the optical writing apparatus provided with the optical deflection | deviation apparatus to which this invention is applied.

Explanation of symbols

1, 30, 40, 50, 60, 70 Optical deflecting device 11, 42, 72 Substrate 12 Liquid crystal layer 13 Liquid crystal molecule 14, 44, 76, 77 Alignment film 15, 74, 75 Electrode 20, 45, 94 Light 21, 41 , 61, 71, 93 Optical deflection elements 22, 51, 62, 78 Electric field forming means 26 Temperature detection means 27 Temperature control means 43 Saw-toothed surfaces 52, 53, 54 Resistance elements 63a, 63b for gradually increasing the electric field between the electrodes , 63c, 64a, 64b, 64c, 65a, 65b, 65c A resistive element that periodically changes the electric field between the electrodes 84 Image display element 89 Optical member 90 Image display control means 96 Light emitting member A Electrode extending direction B Liquid crystal molecule Direction of D D Direction of linear polarization of light R Direction of arrangement of light emitting members

Claims (13)

A pair of substrates facing each other, a liquid crystal layer constituted by a chiral smectic A phase and positioned between the substrates, an alignment film for horizontally aligning the liquid crystal molecules forming the liquid crystal layer on the substrate, and substantially parallel to each other An optical deflection element provided with a plurality of electrodes that are long in a direction substantially parallel to the surface of the substrate,
Electric field forming means for forming an electric field in a direction substantially parallel to the arrangement surface by the electrode,
An optical deflection apparatus characterized in that linearly polarized light transmitted through the optical deflection element is deflected by changing the intensity and / or direction of the electric field formed by the electric field forming means.   2. The optical deflection apparatus according to claim 1, wherein the alignment direction of the liquid crystal molecules and the extending direction of the electrodes are substantially parallel.   3. The optical deflection apparatus according to claim 1, wherein the alignment direction of the liquid crystal molecules is substantially parallel to the direction of linearly polarized light transmitted through the optical deflection element.   4. The optical deflection apparatus according to claim 1, wherein the electric field forming means is disposed between the electrodes, and the intensity of the electric field between the electrodes is determined. An optical deflecting device comprising a resistance element for gradually increasing or decreasing in a direction from an electrode located on one end side to an electrode located on the other end side.   5. The optical deflection apparatus according to claim 4, wherein the resistance value of the resistance element periodically changes in a direction from an electrode located on one end side of the electrodes toward an electrode located on the other end side. An optical deflector characterized by that.   6. An optical deflecting device according to claim 1, wherein at least one of the substrates has a surface having a sawtooth cross section on the side facing the other. A pair of substrates facing each other, a liquid crystal layer constituted by a chiral smectic A phase and positioned between the substrates, an alignment film for horizontally aligning the liquid crystal molecules forming the liquid crystal layer on the substrate, and substantially parallel to each other An optical deflection element having an electrode substantially parallel to the surface of the substrate,
Electric field forming means for forming an electric field in a direction substantially perpendicular to the arrangement surface by the electrode,
At least one of the substrates has a surface having a sawtooth cross section on the side facing the other,
An optical deflection apparatus characterized in that linearly polarized light transmitted through the optical deflection element is deflected by changing the intensity and / or direction of the electric field formed by the electric field forming means.   8. The optical deflection apparatus according to claim 1, further comprising temperature detection means for detecting a temperature of the optical deflection element.   9. The optical deflection apparatus according to claim 8, further comprising temperature control means for controlling the temperature of the optical deflection element based on the temperature detected by the temperature detection means.   An image display element in which a plurality of pixels are arranged two-dimensionally, an optical member for observing an image displayed on the image display element, and an optical member disposed between the optical member and the image display element Observation by the optical member by changing the deflection of the light by the light deflection element according to any one of claims 1 to 9 and the timing at which an image is displayed on the image display element. And an image display control means for increasing the apparent number of pixels of the image to be displayed.   A plurality of light emitting members arranged at predetermined intervals and emitting light toward the writing position, and the respective light emitted from these light emitting members are deflected in the direction in which the light emitting members are arranged, and the light at the writing position is deflected. 10. An optical writing apparatus comprising: the optical deflection element according to claim 1 for making the interval smaller than the predetermined interval.   12. The optical writing device according to claim 11, wherein the light deflecting element is disposed corresponding to each of the light emitting members. An image forming apparatus comprising the optical writing device according to claim 11.

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