JP4574428B2 - Optical axis deflection element, optical path deflection element, optical axis deflection method, optical path deflection method, optical axis deflection apparatus, optical path deflection apparatus, and image display apparatus - Google Patents

Description

  The present invention relates to an optical axis deflecting element that changes the tilt direction of the optical axis of a uniaxial substance by an electric signal, an optical path deflecting element that includes the optical axis deflecting element and deflects the optical path of light by an electric signal, and the optical axis. Optical axis deflection method and optical axis deflection apparatus using deflection element, optical path deflection method using optical axis deflection method, optical path deflection apparatus using optical path deflection element or optical axis deflection apparatus, and optical path The present invention relates to an image display device including a deflection device.

[Definition]
In this specification, “optical path deflecting element” refers to whether the optical path of light is deflected by an external electric signal, that is, the outgoing light is shifted in parallel to the incident light, or is rotated at a certain angle. Or an optical element capable of switching the optical path by combining the two. In this description, the magnitude of the shift is referred to as “shift amount” with respect to the optical path deflection due to the parallel shift, and the rotation amount is referred to as “rotation angle” with respect to the optical path deflection due to rotation. The “optical path deflecting device” means a device that includes such an optical path deflecting element and deflects the optical path of light.

  In addition, the “pixel shift element (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 display An optical member for observing an image pattern displayed on the element, and an optical path deflecting unit for deflecting an optical path between the image display element and the optical member for each of a plurality of subfields obtained by temporally dividing the image field, An image display in which the apparent number of pixels of the image display element is multiplied and displayed by displaying an image pattern in which the display position is shifted in accordance with the deflection state of the optical path for each subfield by the optical path deflecting means. It means the optical path deflecting means in the apparatus. Therefore, basically, it can be said that the optical path deflecting element and the optical path deflecting device defined above can be applied as optical path deflecting means (pixel shift element (pixel shifting element)).

Conventionally, various techniques relating to an optical path deflecting element (or an optical deflecting element) or a pixel shift element using a liquid crystal material, an image display device using these, and the like have been proposed (see, for example, Patent Documents 1 to 6). However, in the conventional optical path deflection element and pixel shift element,
(1) High cost due to the complicated configuration, increase in size of the apparatus, loss of light amount, optical noise such as ghost, or reduction in resolution,
(2) Positional accuracy and durability, especially in the case of a configuration having moving parts, problems of vibration and sound,
(3) Response speed problem in nematic liquid crystal, etc.
and so on.

Therefore, the applicant first improved the problem in the conventional optical path deflecting element, i.e., the high cost, the large size of the apparatus, the loss of light amount, the optical noise, and the like due to the complicated structure. For the purpose of providing an optical path deflecting element and a device that are simple and small in size, have little light loss, optical noise, resolution reduction, and can be reduced in cost, an optical path deflecting element configured as shown in FIG. 18 has been proposed. (See Patent Document 7).
The optical path deflecting element 1 has a pair of transparent substrates 2 and 3, an alignment film 4 provided on at least one of the pair of substrates 2 and 3, and a homeotropic alignment filled between the pair of substrates 2 and 3. A liquid crystal layer 5 composed of a chiral smectic C phase, and an electrode pair 6 composed of at least one pair of electrodes 6a and 6b for applying an electric field to the liquid crystal 5; It is set as the structure which applies an electric field to. Since this optical path deflecting element 1 uses a liquid crystal 5 composed of a chiral smectic C phase, compared to the conventional optical path deflecting element, the cost is increased due to the complicated structure, the size of the apparatus is increased, the light loss is reduced. The problem of optical noise can be improved, and the dullness of responsiveness in conventional smectic A liquid crystals and nematic liquid crystals can also be improved, enabling high-speed response.

Japanese Patent Laid-Open No. 6-18940 JP-A-9-133904 Japanese Patent No. 2939826 JP-A-5-313116 JP-A-6-324320 JP-A-10-133135 JP 2002-328402 A “Crystal optics”, Japan Society of Applied Physics, Optical Society, p198

In the optical path deflecting element 1 described in Patent Document 7, when an electric field is applied in a direction perpendicular to the helical axis of the chiral smectic C phase, that is, in a direction parallel to the smectic layer, the liquid crystal molecules are conical in the smectic layer. Is considered to rotate. At this time, the ratio of the liquid crystal molecules aligned in the same direction changes according to the characteristics such as the helical pitch and spontaneous polarization of the liquid crystal layer, and the inclination direction of the optical axis of the liquid crystal layer corresponding to the average alignment direction of the liquid crystal molecules is Change.
Here, as described in Patent Document 7, when a conoscopic image is observed with a polarizing microscope from the normal direction of the chiral smectic C phase liquid crystal layer under no electric field, the cross image is located at the center. It can be confirmed that it has a uniaxial optical axis. FIG. 19 shows a model of liquid crystal molecular arrangement of chiral smectic C phase (model of helical structure change by electric field). The molecular layers having the tilt angle θ are overlapped with each other while forming a spiral structure. In the electric field E = 0, the liquid crystal director direction is spatially averaged by the symmetrical spiral structure as shown in FIG. The averaged optical axis of the liquid crystal layer faces the normal direction of the layer, and is optically isotropic with respect to incident light parallel to the optical axis. Next, when a relatively small electric field 0 <E <Es is applied in a direction parallel to the liquid crystal layer, a rotational moment is generated in the liquid crystal molecules due to the action of the electric field E on the spontaneous polarization Ps, as shown in FIG. The spiral structure is distorted and asymmetric, and the average optical axis is tilted in one direction. At this time, distortion increases as the electric field strength increases, and the average tilt angle of the optical axis also increases. This can be confirmed from the movement of the cross image of the conoscopic image. When the electric field strength is further increased, the spiral structure disappears as shown in FIG. 19C at a certain threshold electric field Es or more and becomes optically substantially uniaxial. The tilt angle of the optical axis at this time is equal to the tilt angle θ of the liquid crystal director. Further, even if the electric field is increased, the tilt angle θ does not change, and the tilt angle of the optical axis becomes constant.
Thus, when a sufficiently large electric field is applied to the liquid crystal layer, the alignment directions of the liquid crystal molecules in each smectic layer are aligned, and the spiral is unwound. Also, when the electric field direction is reversed, the tilt direction of the optical axis of the liquid crystal layer is also reversed, so that it functions as an optical axis deflecting element or a dynamic birefringent plate and applied to an optical path deflecting element or an optical path deflecting device using the same. it can.

When the above optical path deflecting element (optical axis deflecting element) is applied to an image display device or the like, it is necessary to design the width of the effective area that transmits light wide. When applying a parallel electric field (electric field in a direction parallel to the substrate surface (liquid crystal layer)) necessary for driving the layer, it is necessary to apply a very large voltage of several kilovolts or more between the effective area widths. .
However, when a very large voltage of several kilovolts or more is applied between the effective area widths of the optical path deflecting element, there is a risk of discharge and noise generation in the apparatus, and the power source is increased in size and power consumption. Problems such as an increase in

The present invention has been made in view of the above circumstances, and even if the voltage value to be applied is set to ½ or less of that of the prior art, the same optical axis deflection effect as that of the prior art can be obtained, and discharge and noise can be prevented. An object of the present invention is to provide an optical axis deflecting element having a configuration that can be miniaturized.
The present invention also provides an optical path deflecting element that can obtain the same optical path deflecting effect as that of the prior art by using the optical axis deflecting element and can be driven with a relatively small applied voltage with respect to a large effective area. Objective.
Furthermore, the present invention provides an optical axis deflection method and an optical axis deflection apparatus that can obtain an optical axis deflection effect similar to the conventional one using the optical axis deflection element, and that can prevent discharge and noise, reduce the size of the power supply, and the like. For the purpose.
A further object of the present invention is to provide an optical path deflection method capable of obtaining the same optical path deflection effect as that of the prior art using the optical axis deflection method.
Furthermore, the present invention provides the same optical path deflecting effect as the conventional one using the optical path deflecting element or the optical axis deflecting device, and can be driven with a relatively small applied voltage with respect to a large effective area. It is an object of the present invention to provide an optical path deflecting device having a configuration capable of preventing the power source and reducing the size of the power source.
It is another object of the present invention to provide an image display device that uses the optical path deflecting device and has high definition, low cost, and low power consumption even when an image display element having a relatively small number of pixels is used.

In order to achieve the above object, the present invention adopts the following means.
The first means of the present invention includes a pair of transparent substrates, a liquid crystal layer capable of forming a chiral smectic C phase having a homeotropic orientation filled between the pair of substrates, and at least both ends of the liquid crystal layer. In an optical axis deflection element having an electrode that is arranged and generates an electric field in a direction parallel to the substrate surface (hereinafter referred to as a parallel electric field), an effective area between the electrodes is divided into a plurality of areas, and each area is divided. In addition, one or more divided electrodes are arranged so that a parallel electric field can be independently applied thereto (claim 1).

  In the second means, in the optical axis deflecting element of the first means, the width of the effective area between the electrodes is L, and the voltage value when the voltage is applied to the entire width of the effective area is V. When the average electric field strength is E and the constant electric field application period is T, the effective region can be divided into N pieces (N is an integer of 2 or more) in the electric field application direction and a parallel electric field can be applied. One or more divided electrodes are arranged so as to become (Claim 2).

According to a third means, in the optical axis deflecting element of the first or second means, the divided electrodes in the effective area are formed in a line-shaped transparent manner formed on the substrate surface corresponding to both ends of each divided area. It is an electrode (Claim 3).
According to a fourth means, in the optical axis deflecting element of the first or second means, the divided electrode in the effective region is composed of a plurality of transparent line electrodes formed on a substrate surface, and the transparent line electrode A dielectric layer is formed between the county surface and the liquid crystal layer, and each transparent line electrode is electrically connected in series by a resistor (claim 4).
According to a fifth means, in the optical axis deflecting element of the first or second means, the electrodes and the divided electrodes in the effective area are lines formed on the substrate surface corresponding to both ends of each divided area. And a transparent resistor layer is formed on the substrate surface (claim 5).

According to a sixth means, in the optical axis deflecting element of the third or fifth means, the line-shaped transparent electrodes formed on the pair of substrate surfaces are arranged at different positions on the projection plane with respect to the light transmission direction. (Claim 6).
Seventh means includes, in the optical axis deflecting element of the fourth means, a position on both substrates of the transparent line electrodes which are directly connected to a power source and function as divided electrodes among the plurality of transparent line electrodes. A different position is set on the projection plane with respect to the light transmission direction.

The eighth means is the parallel electric field on the projection plane with respect to the light transmission direction with respect to the positional relationship of the divided electrodes arranged at different positions in the optical axis deflection element of the sixth or seventh means. (ΔZ / 2)> ΔX is set, where ΔX is the maximum value of the amount of deviation in the direction and ΔZ is the interval in the thickness direction of the liquid crystal layer (claim 8).
According to a ninth means, in the optical axis deflecting element of any one of the first to eighth means, the divided electrode for dividing the effective region into a plurality of parts is composed of at least a pair of line-shaped electrodes, and each divided region is sequentially timed. In the liquid crystal layer corresponding to the electric field applied between the pair of line-shaped electrodes, the electric field application periods are set to overlap (claim 9).

  The tenth means is an optical path deflecting element that deflects the optical path of light in response to an electric signal, and comprises the optical axis deflecting element of any one of the first to ninth means, Incident light is linearly polarized, and the plane of polarization of the linearly polarized light is set in a direction orthogonal to the direction of application of the parallel electric field in the element, thereby shifting the position of the outgoing optical path relative to the incident optical path. (Claim 10).

  The eleventh means includes a pair of transparent substrates, a liquid crystal layer capable of forming a chiral smectic C phase having a homeotropic alignment filled between the pair of substrates, and a substrate disposed at least on both ends of the liquid crystal layer. An optical axis deflecting element having an electrode for generating an electric field in a direction parallel to the surface (hereinafter referred to as a parallel electric field), and a voltage applying means for applying a voltage to the electrode of the optical axis deflecting element. In the optical axis deflection method, the orientation direction of the liquid crystal molecules is switched by switching the electric field direction of the deflection element, the tilt direction of the optical axis with respect to the layer normal of the liquid crystal layer is switched, and the outgoing optical path for the incident light is switched. The optical axis deflecting element of any one of the first to ninth means is used as an element, and a voltage is selectively applied to each electrode of the optical axis deflecting element by the voltage applying means. To (claim 11).

  The twelfth means is the optical axis deflection method of the eleventh means, wherein the effective area width of the optical axis deflecting element is L, and the voltage value when the voltage is applied to the entire effective area width is V, When the average parallel electric field strength applied is E and the constant electric field application period is T, the electric field is applied by dividing the effective region into N pieces (N is an integer of 2 or more) in the electric field application direction. In order to apply one or more polarized electrodes as possible and to apply an average parallel electric field strength E to L / N which is the width of each divided region, the voltage value of V / N is set to T / The parallel electric field strength E is uniformly applied to the entire effective area when time-averaged by temporarily applying the voltage within a period N and switching the voltage application area in time sequence. Item 12).

  A thirteenth means is the optical axis deflection method of the eleventh means, wherein the effective area of the optical axis deflection element is divided into at least a first area and a second area, and an electric field is generated in the first area. A voltage is temporarily applied to the optical axis of the liquid crystal layer in the first region, the voltage in the first region is removed after the desired optical axis tilt state is reached, and then an electric field is immediately applied to the second region. A voltage is temporarily applied between the second electrodes to cause the optical axis of the liquid crystal layer of the second region to tilt, and after the desired optical axis tilt state is reached, the voltage of the second region is removed, Before the time when the optical axis tilt state of the first region returns to the initial state, an electric field having the same polarity or reverse polarity is temporarily applied between the first electrodes again, so that the liquid crystal layer of the first region is The operation of maintaining the optical axis tilt state or switching to the reverse polarity tilt state, By sequentially performed between the first region and the second region, and wherein the maintaining substantially uniform inclination of the optical axis as a whole effective region within a certain period of time (claim 13).

  The fourteenth means is the optical axis deflection method of the eleventh means, wherein the effective area of the optical axis deflection element is divided into N areas (N is an integer of 2 or more) of the first area to the Nth area, A voltage is temporarily applied between the first electrodes that generate an electric field in the region to tilt the optical axis of the liquid crystal layer in the first region, and after the desired optical axis tilt state is reached, the voltage in the first region is removed After that, a voltage is temporarily applied between the second electrodes that immediately generate an electric field in the second region to tilt the optical axis of the liquid crystal layer in the second region, and after the desired optical axis tilted state is reached. The operation of removing the voltage of the second region is performed up to the Nth region, and before the time when the optical axis tilt state of the first region returns to the initial state, the first electrode is temporarily temporarily re-same between the previous time. By applying an electric field of polarity or reverse polarity, the optical axis tilt state of the liquid crystal layer in the first region is maintained, or The operation of switching to the reverse polarity tilt state is sequentially performed between the first region to the Nth region, so that the tilt state of the optical axis is maintained substantially uniform as a whole effective region within a certain period. (Claim 14).

  The fifteenth means is the optical axis deflection method according to any one of the first to fourteenth means, wherein the direction of the optical axis is changed at the timing of reversing the direction of the parallel electric field of the entire effective area of the optical axis deflection element. The temporary electric field application time for inversion is set shorter than the temporary electric field application time for maintaining the optical axis in one direction (claim 15).

  A sixteenth means is the optical axis deflection method according to any one of the first to fifteenth means, wherein a split electrode for applying a parallel electric field is formed on the substrate surface within an effective region of the optical axis deflection element. A plurality of transparent line electrodes, a dielectric layer is formed between the surface of the transparent line electrode group and the liquid crystal layer, and each transparent line electrode is electrically connected in series by a resistor, A potential difference is applied between the two transparent line electrodes at positions corresponding to the width (claim 16).

  A seventeenth means is a method of applying a voltage between the corresponding electrodes in order to generate an electric field in a certain divided region of the optical axis deflection element in the optical axis deflection method of any one of the first to sixteenth means. In this state, the voltage value between the electrodes is controlled so that the corresponding electrodes have the same potential so that unnecessary electric fields are not generated in the adjacent divided regions. ).

  The eighteenth means is an optical path deflection method using the optical axis deflection method of any one of the first to seventeenth means, and the incident light to the optical axis deflection element is made into linearly polarized light. By setting the plane of polarization in a direction orthogonal to the direction of application of the parallel electric field in the element, the position of the outgoing optical path with respect to the incident optical path is shifted in parallel (claim 18).

  A nineteenth means includes a pair of transparent substrates, a liquid crystal layer capable of forming a chiral smectic C phase having a homeotropic alignment filled between the pair of substrates, and a substrate disposed at least on both ends of the liquid crystal layer. An optical axis deflecting element having an electrode for generating an electric field in a direction parallel to the surface (hereinafter referred to as a parallel electric field), and voltage applying means for applying a voltage to the electrode of the optical axis deflecting element. In the optical axis deflecting device, the orientation direction of the liquid crystal molecules is switched by switching the electric field direction of the deflecting element to switch the tilt direction of the optical axis with respect to the normal line of the liquid crystal layer, and the outgoing optical path for the incident light is switched. The optical axis deflecting element of any one of the first to ninth means is provided as an element, and the voltage applying means includes means for selectively applying a voltage to each electrode of the optical axis deflecting element. The constitution (claim 19).

  According to a twentieth means, in the optical axis deflecting device of the nineteenth means, the effective area width of the optical axis deflecting element is L, and the voltage value when a voltage is applied to the entire effective area width is V, When the average parallel electric field strength applied is E and the constant electric field application period is T, the electric field is applied by dividing the effective region into N pieces (N is an integer of 2 or more) in the electric field application direction. In order to apply one or more polarized electrodes as possible and to apply an average parallel electric field strength E to L / N which is the width of each divided region, the voltage value of V / N is set to T / The parallel electric field strength E is uniformly applied to the entire effective area when time-averaged by temporarily applying the voltage within a period N and switching the voltage application area in time sequence. Item 20).

  The twenty-first means is the optical axis deflecting device of the nineteenth means, wherein the effective area of the optical axis deflecting element is divided into at least a first area and a second area, and an electric field is generated in the first area. A voltage is temporarily applied to the optical axis of the liquid crystal layer in the first region, the voltage in the first region is removed after the desired optical axis tilt state is reached, and then an electric field is immediately applied to the second region. A voltage is temporarily applied between the second electrodes to cause the optical axis of the liquid crystal layer of the second region to tilt, and after the desired optical axis tilt state is reached, the voltage of the second region is removed, Before the time when the optical axis tilt state of the first region returns to the initial state, an electric field having the same polarity or reverse polarity is temporarily applied between the first electrodes again, so that the liquid crystal layer of the first region is The operation of maintaining the optical axis tilt state or switching to the reverse polarity tilt state, By sequentially performed between the first region and the second region, and wherein the maintaining substantially uniform inclination of the optical axis as a whole effective region within a certain period of time (claim 21).

  The twenty-second means is the optical axis deflecting device of the nineteenth means, wherein the effective area of the optical axis deflecting element is divided into N (N is an integer of 2 or more) from the first area to the Nth area, A voltage is temporarily applied between the first electrodes that generate an electric field in the region to tilt the optical axis of the liquid crystal layer in the first region, and after the desired optical axis tilt state is reached, the voltage in the first region is removed After that, a voltage is temporarily applied between the second electrodes that immediately generate an electric field in the second region to tilt the optical axis of the liquid crystal layer in the second region, and after the desired optical axis tilted state is reached. The operation of removing the voltage of the second region is performed up to the Nth region, and before the time when the optical axis tilt state of the first region returns to the initial state, the first electrode is temporarily temporarily re-same between the previous time. By applying an electric field of polarity or reverse polarity, the optical axis tilt state of the liquid crystal layer in the first region is maintained, or The operation of switching to the reverse polarity tilt state is sequentially performed between the first region to the Nth region, so that the tilt state of the optical axis is maintained substantially uniform as a whole effective region within a certain period. (Claim 22).

  The twenty-third means is the optical axis deflecting device according to any one of the nineteenth to twenty-second means, wherein the direction of the optical axis is changed at the timing of reversing the direction of the parallel electric field of the entire effective area of the optical axis deflecting element. The temporary electric field application time for inversion is set shorter than the temporary electric field application time for maintaining the optical axis in one direction (claim 23).

  According to a twenty-fourth means, in the optical axis deflecting device according to any one of the nineteenth to twenty-third means, a split electrode for applying a parallel electric field is formed on the substrate surface within an effective region of the optical axis deflecting element. A plurality of transparent line electrodes, a dielectric layer is formed between the surface of the transparent line electrode group and the liquid crystal layer, and each transparent line electrode is electrically connected in series by a resistor, A potential difference is applied between the two transparent line electrodes at a position corresponding to the width (claim 24).

  The twenty-fifth means applies a voltage between the corresponding electrodes in order to generate an electric field in a certain divided region of the optical axis deflection element in the optical axis deflection apparatus according to any one of the nineteenth to twenty-fourth means. In this state, the voltage value between the electrodes is controlled so that the corresponding electrodes have the same potential so that an unnecessary electric field is not generated in the adjacent divided regions. ).

  The twenty-sixth means is an optical path deflecting device that deflects an optical path of light in accordance with an electric signal, and selectively applies voltages to the optical path deflecting element of the tenth means and each electrode of the optical path deflecting element in accordance with the electric signal. And a voltage applying means for applying a voltage (claim 26).

  The twenty-seventh means is an optical path deflecting device that deflects the optical path of light in accordance with an electric signal, and comprises the optical axis deflecting device of any one of the nineteenth to twenty-fifth means, and the incident light to the optical axis deflecting element. Is set to be linearly polarized light, and the plane of polarization of the linearly polarized light is set in a direction orthogonal to the direction of application of the parallel electric field in the element, thereby shifting the position of the outgoing optical path with respect to the incident optical path. (Claim 27).

The twenty-eighth means includes an image display element in which a plurality of pixels that can control light according to image information are two-dimensionally arranged, a light source and an illumination device that illuminate the image display element, and an image displayed on the image display element In an image display apparatus having an optical device for observing a pattern, display drive means formed by a plurality of subfields obtained by dividing an image field in time, and optical path deflecting means for deflecting the optical path of light emitted from each pixel A twenty-sixth or twenty-seventh optical path deflecting device is provided as the optical path deflecting means (claim 28).
According to a twenty-ninth aspect, in the image display device of the twenty-eighth means, an image pattern corresponding to a state in which a display position is shifted according to a deflection state of an optical path for each subfield by the optical path deflecting device is displayed on the image display element. In this case, the apparent number of pixels of the image display element is multiplied and displayed (claim 29).

In the optical axis deflection element of the first or second means, the effective region between the electrodes is divided into a plurality of regions, and one or more divided electrodes are provided so that a parallel electric field can be independently applied to each region. With this arrangement, even if the voltage value to be applied is set to ½ or less of the conventional voltage value, the same optical axis deflection effect as the conventional one can be obtained, and discharge and noise can be prevented, and the power source can be miniaturized.
More specifically, when a parallel electric field is applied to a liquid crystal layer capable of forming a chiral smectic C phase having homeotropic alignment, the responsiveness after the electric field is turned on is good, and the tilt direction of the optical axis is immediately switched. Since the response is relatively slow, it takes a sufficient time for the optical axis to return to the initial state. That is, in order to keep the tilt direction of the optical axis in one direction, it is not always necessary to apply a constant electric field. The electric field is turned off immediately after the change in liquid crystal alignment is completed by turning on the electric field, and the electric field is again after a certain time. By turning ON, the liquid crystal alignment state (inclined state of the optical axis) can be continuously maintained. Therefore, the effective area of the optical axis deflection element is spatially and electrically divided, and one or more divided electrodes are arranged so that a parallel electric field can be independently applied to each area. By applying short-time electric fields sequentially in time, the liquid crystal alignment state at the time of electric field application can be substantially maintained for the entire effective region. At this time, since the width of the divided region to which the electric field is applied can be set narrow, when applying a constant electric field strength, the applied voltage value itself can be set to be ½ or less of the conventional voltage value. Therefore, discharge and noise in the apparatus can be prevented, and the power supply can be reduced in size.

  In the optical axis deflecting element of the third means, in addition to the above configuration and effect, the electrode that electrically divides the effective region is a line-shaped transparent electrode, so that the transmitted light is prevented from being blocked. The transmittance can be improved.

By the way, in the optical axis deflecting element of the first or second means, when the effective area is wide and the number of divisions is reduced, the width of the divided areas becomes relatively wide. At this time, if a voltage is applied only to both ends of the divided region, the electric field strength at the center of the divided region may be weakened.
Therefore, in the optical axis deflecting element of the fourth means, the electrode for applying a parallel electric field in the effective region is composed of a large number of transparent line electrodes formed on the substrate surface, and each transparent line electrode group is formed by a resistor. As a configuration electrically connected in series, by applying a potential difference between two transparent line electrodes at positions corresponding to the width of the divided region, a desired direction in a direction parallel to the liquid crystal layer in the divided region is obtained. A potential distribution can be formed. At this time, since the electric field distribution is disturbed near the edge portion of each line electrode, the electric field distribution in the liquid crystal layer can be made uniform by forming a dielectric layer between the surface of the transparent line electrode group and the liquid crystal layer.
In the optical axis deflecting element of the fifth means, a transparent resistor layer is formed on the substrate surface in the effective area, so that when a potential difference is applied between electrodes at positions corresponding to the width of the divided area, A desired potential distribution can be formed in a direction parallel to the liquid crystal layer in the region. Therefore, the electric field distribution in the liquid crystal layer can be made uniform.

In the optical axis deflecting elements of the first to fifth means, the boundary of the divided area in the effective area is clearly set, but an area that is always in a low electric field state is generated at the boundary part, and the optical axis is inclined. This causes the corners to become locally smaller. In order to prevent this and improve the uniformity of the operation of the entire effective area, it is preferable to set the boundaries of the divided areas relatively unclearly. That is, by providing a certain width as the boundary region, the uniformity of the optical axis deflection operation is improved.
Therefore, in the optical axis deflecting element of the sixth means, the line-shaped transparent electrodes formed on the pair of substrate surfaces are arranged at different positions on the projection surface with respect to the light transmission direction, that is, the divided electrodes on the upper and lower substrates are arranged. By shifting the position, the boundary position is changed in the thickness direction of the liquid crystal layer. Therefore, the boundary region is formed obliquely in the liquid crystal layer in the vicinity of the boundary, and the boundary region becomes unclear when viewed in the light transmission direction, thereby preventing the generation of a local low electric field region.

In the optical axis deflecting element of the seventh means, the position of the transparent line electrode, which is directly connected to a power source and functions as a divided electrode among the multiple transparent line electrodes, is projected on the light transmission direction. By setting different positions on the surface, that is, by setting the divided electrodes of the upper and lower substrates to be shifted, the same effect as the sixth means can be obtained.
However, when the amount of deviation of the divided electrodes increases, a potential difference occurs in the thickness direction of the liquid crystal layer. Therefore, in the optical axis deflecting element of the eighth means, the maximum value of the deviation amount in the parallel electric field direction on the projection plane with respect to the light transmission direction is set with respect to the positional relationship of the divided electrodes arranged at different positions. When ΔX is set and the interval in the liquid crystal layer thickness direction is ΔZ, by setting (ΔZ / 2)> ΔX, the potential difference in the thickness direction of the liquid crystal layer can be kept relatively small. Therefore, the change in the electric field direction in the liquid crystal layer in the vicinity of the boundary region can be suppressed to be relatively small, and the uniformity of the optical axis in the effective region can be maintained.

  In the above means, since the position of the electrode functioning as the divided electrode is fixed, the boundary region is spatially blurred by setting the position spatially shifted, but the electrode functioning as the divided electrode The boundary region can also be spatially blurred by shifting the position of. Therefore, in the optical axis deflecting element of the ninth means, the divided electrode that divides the effective region into a plurality is composed of at least a pair of line-shaped electrodes, and the electric field applied to each of the divided regions in time order is applied to the pair of line-shaped electrodes. In the liquid crystal layer corresponding to the gap, the electric field application periods are set to overlap. That is, even if the position of the divided region to which the electric field is applied is switched during a certain period, the position of the effective boundary region is switched by arranging the electrodes so that the divided regions overlap. Therefore, it is possible to eliminate the low electric field region that occurs when the boundary region is clearly fixed.

  The optical path deflecting element of the tenth means comprises the optical axis deflecting element of any one of the first to ninth means, and the incident light to the optical axis deflecting element is linearly polarized light, and the plane of polarization of the linearly polarized light is By setting the direction perpendicular to the direction in which the parallel electric field is applied in the element, the light beam is shifted in the liquid crystal layer according to the tilt direction of the optical axis of the liquid crystal layer, and the position of the outgoing optical path is parallel to the incident optical path. Shift to. Therefore, the emission position of the light beam can be switched by switching the electric field direction and switching the tilt direction of the optical axis.

  In the optical axis deflection method of the eleventh means, the optical axis deflection element of any one of the first to ninth means is used as the optical axis deflection element, and the voltage application means selectively selects each electrode of the optical axis deflection element. Therefore, even if the applied voltage value is set to ½ or less of the conventional voltage, the same optical axis deflection effect as that of the conventional one can be obtained, and discharge and noise can be prevented, and the power supply can be reduced in size.

  In the optical axis deflection method of the twelfth, thirteenth or fourteenth means, the effective area of the optical axis deflection element is spatially and electrically divided so that a parallel electric field can be independently applied to each area. By disposing one or more divided electrodes and sequentially applying a short electric field to each divided region in time, the liquid crystal alignment state at the time of applying the electric field can be substantially maintained for the entire effective region. At this time, since the width of the divided region to which the electric field is applied can be set narrow, when applying a constant electric field strength, the applied voltage value itself can be set to be ½ or less of the conventional voltage value. Therefore, discharge and noise in the apparatus can be prevented, and the power supply can be reduced in size.

  In the optical axis deflection method of the fifteenth means, in the optical axis deflection method of any one of the first to fourteenth means, the direction of the parallel electric field of the entire effective area of the optical axis deflection element is reversed to tilt the optical axis. When reversing the direction periodically, the temporary electric field application time for reversing the optical axis direction is set shorter than the temporary electric field application time for maintaining the optical axis in one direction. By doing so, the period in which the electric field directions are different between the divided regions can be shortened. Therefore, it is possible to set a long period during which the optical axis tilt directions of the entire effective region are coincident.

  According to an optical axis deflection method of the sixteenth means, in the optical axis deflection method of any one of the first to fifteenth means, the divided electrode for applying a parallel electric field in the effective region of the optical axis deflection element is a substrate surface. It consists of a number of transparent line electrodes formed on top, and a dielectric layer is formed between the surface of the transparent line electrode group and the liquid crystal layer, and each transparent line electrode is electrically connected in series by a resistor. By applying a potential difference between the two transparent line electrodes at a position corresponding to the width of the divided region, a desired potential distribution can be formed in a direction parallel to the liquid crystal layer in the divided region. At this time, since the electric field distribution is disturbed near the edge portion of each line electrode, the electric field distribution in the liquid crystal layer can be made uniform by forming a dielectric layer between the surface of the transparent line electrode group and the liquid crystal layer.

  By the way, in the optical axis deflection method of any one of the first to sixteenth means, a voltage is applied only between the corresponding electrodes in order to generate an electric field in a certain divided region, and it corresponds to the other divided regions. When the electrode is electrically floated, an electric field in the opposite direction may be generated in other divided regions. Therefore, in the optical axis deflection method of the seventeenth means, the optical value of the liquid crystal layer is controlled by controlling the voltage value between the electrodes so that the corresponding electrodes have the same potential except in the divided region in the electric field application state. Generation of an unnecessary electric field that disturbs the inclined state of the shaft can be reliably prevented.

  In the optical path deflection method of the eighteenth means, the optical axis deflection method of any one of the first to seventeenth means is used, the incident light to the optical axis deflection element is made linearly polarized light, and the polarization plane of the linearly polarized light is the element. By setting the direction perpendicular to the direction in which the parallel electric field is applied, the light beam is shifted in the liquid crystal layer according to the tilt direction of the optical axis of the liquid crystal layer, and the position of the outgoing optical path is made parallel to the incident optical path. shift. Therefore, the emission position of the light beam can be switched by switching the electric field direction and switching the tilt direction of the optical axis.

  The optical axis deflecting device of the nineteenth means comprises the optical axis deflecting element of any one of the first to ninth means as the optical axis deflecting element, and is selectively applied to each electrode of the optical axis deflecting element by the voltage applying means. Therefore, even if the applied voltage value is set to ½ or less of the conventional voltage, the same optical axis deflection effect as that of the conventional one can be obtained, and discharge and noise can be prevented, and the power supply can be reduced in size.

  In the optical axis deflecting device of the twentieth, twenty-first or twenty-second means, the effective area of the optical axis deflecting element is spatially and electrically divided so that a parallel electric field can be independently applied to each area. By disposing one or more divided electrodes and sequentially applying a short electric field to each divided region in time, the liquid crystal alignment state at the time of applying the electric field can be substantially maintained for the entire effective region. At this time, since the width of the divided region to which the electric field is applied can be set narrow, when applying a constant electric field strength, the applied voltage value itself can be set to be ½ or less of the conventional voltage value. Therefore, discharge and noise in the apparatus can be prevented, and the power supply can be reduced in size.

  In the optical axis deflecting device of the twenty-third means, in the optical axis deflecting device of any one of the nineteenth to twenty-second means, the direction of the parallel electric field of the entire effective area of the optical axis deflecting element is reversed to tilt the optical axis. When reversing the direction periodically, the temporary electric field application time for reversing the optical axis direction is set shorter than the temporary electric field application time for maintaining the optical axis in one direction. By doing so, the period in which the electric field directions are different between the divided regions can be shortened. Therefore, it is possible to set a long period during which the optical axis tilt directions of the entire effective region are coincident.

  In the optical axis deflecting device of the twenty-fourth means, in the optical axis deflecting method of any one of the nineteenth to twenty-third means, the divided electrode for applying a parallel electric field in the effective area of the optical axis deflecting element is provided on the substrate surface. It consists of a number of transparent line electrodes formed on top, and a dielectric layer is formed between the surface of the transparent line electrode group and the liquid crystal layer, and each transparent line electrode is electrically connected in series by a resistor. By applying a potential difference between the two transparent line electrodes at a position corresponding to the width of the divided region, a desired potential distribution can be formed in a direction parallel to the liquid crystal layer in the divided region. At this time, since the electric field distribution is disturbed near the edge portion of each line electrode, the electric field distribution in the liquid crystal layer can be made uniform by forming a dielectric layer between the surface of the transparent line electrode group and the liquid crystal layer.

  By the way, in the optical axis deflecting device of any one of the nineteenth to twenty-fourth means, a voltage is applied only between the corresponding electrodes in order to generate an electric field in a certain divided region, and it corresponds to the other divided regions. When the electrode is electrically floated, an electric field in the opposite direction may be generated in other divided regions. Therefore, in the optical axis deflecting device of the twenty-fifth means, the optical value of the liquid crystal layer is controlled by controlling the voltage value between the electrodes so that the corresponding electrodes have the same potential except in the divided region in the electric field application state. Generation of an unnecessary electric field that disturbs the inclined state of the shaft can be reliably prevented.

  The optical path deflecting device of the twenty-sixth means comprises the optical path deflecting element of the tenth means and voltage applying means for selectively applying a voltage to each electrode of the optical path deflecting element in accordance with the electrical signal. The light beam is shifted in the liquid crystal layer according to the tilt direction of the optical axis of the liquid crystal layer, and the position of the outgoing optical path with respect to the incident optical path can be shifted in parallel. By switching the inclination direction, the light emission position can be switched.

  The optical path deflecting device of the twenty-seventh means comprises the optical axis deflecting device of any one of the nineteenth to twenty-fifth means, wherein the incident light to the optical axis deflecting element is linearly polarized light, and the polarization plane of the linearly polarized light is the element By setting the direction perpendicular to the direction in which the parallel electric field is applied, the light beam is shifted in the liquid crystal layer according to the tilt direction of the optical axis of the liquid crystal layer, and the position of the outgoing optical path is made parallel to the incident optical path. shift. Therefore, the emission position of the light beam can be switched by switching the electric field direction and switching the tilt direction of the optical axis.

  In the image display devices of the 28th and 29th means, a 26 or 27 optical path deflecting device is provided as the optical path deflecting means, and a large area optical path deflecting element (optical axis deflecting element) that can be driven at a relatively low voltage. Therefore, even if an image display element having a relatively small number of pixels is used, a high-definition image can be obtained. Therefore, a high-definition, low-cost, low power consumption image display apparatus can be realized.

Hereinafter, the configuration, operation and action of the present invention will be described in detail with reference to the drawings.
First, a configuration example of an optical axis deflection element will be described with reference to FIG. 1 as an embodiment of the present invention. As shown in FIG. 1, a pair of transparent substrates 11 and 12 are provided so as to face each other. As the transparent substrates 11 and 12, glass, quartz, plastic, or the like can be used, but a transparent material having no birefringence is preferable. The substrates 11 and 12 have a thickness of several tens of μm to several mm. Vertical alignment films 13 and 14 are formed on the inner side surfaces of the substrates 11 and 12. The vertical alignment films 13 and 14 are not particularly limited as long as the liquid crystal molecules are vertically aligned (homeotropic alignment) with respect to the substrate surface. However, a vertical alignment agent for a liquid crystal display, a silane coupling agent, a SiO ₂ vapor deposition film, or the like is used. Can be used. The vertical alignment (homeotropic alignment) referred to in the present invention includes not only a state in which liquid crystal molecules are aligned perpendicular to the substrate surface but also an alignment state in which the liquid crystal molecules are tilted to several tens of degrees.

  The distance between the substrates 11 and 12 is defined with a spacer interposed therebetween, and a liquid crystal layer 15 is formed between the substrates, and a pair of electrodes 16 a and 16 b are formed on both ends of the liquid crystal layer 15. As the spacer, a sheet member having a thickness of about several μm to several mm or particles having the same particle size is used, and is preferably provided outside the effective region of the element. As the electrodes 16a and 16b, a metal sheet such as aluminum, copper, or chromium, or the aforementioned metal film formed on the substrate surface is used. It is preferable to use a metal sheet having a thickness comparable to the thickness of the liquid crystal layer 15 for the electrodes 16 a and 16 b disposed at both ends of the effective region of the element. Further, as the divided electrode 17 provided in the effective region and for electrically dividing the effective region, a metal sheet or the like may be used similarly to the above electrode, but a uniform liquid crystal layer is formed and the orientation property is increased. In order to maintain the above, it is preferable to form a metal film or the like disposed on the substrate surface without providing divided electrodes in the liquid crystal layer. The width of the divided electrode 17 is preferably as narrow as possible, but in actuality, the width is about several microns. As a more preferable example in FIG. 1, the spacer members at both ends of the effective region and the metal sheet members (electrodes) 16a and 16b are common, and the thickness of the liquid crystal layer is defined by the thickness of the metal sheet member. As an example, the liquid crystal layer 15 is a liquid crystal capable of forming a smectic C phase. The divided electrode 17 used was a chromium film deposited on a substrate and processed into a line having a width of 5 μm. An electric field (hereinafter referred to as a parallel electric field) is applied in a direction parallel to the substrate surface of the liquid crystal layer 15 by applying a potential difference between these electrodes sandwiching each divided region by a voltage applying means (not shown).

  Here, the liquid crystal layer 15 capable of forming a smectic C phase will be described in detail. A “smectic liquid crystal” is a liquid crystal layer in which the major axis direction of liquid crystal molecules is arranged in a layered manner (smectic layer). Regarding such a liquid crystal layer, a liquid crystal in which the normal direction of the layer (layer normal direction) and the major axis direction of the liquid crystal molecules coincide with each other is referred to as “smectic A phase”, and a liquid crystal that does not coincide with the normal direction. This is called “smectic C phase”. A ferroelectric liquid crystal composed of a smectic C phase generally has a so-called spiral structure in which the direction of the liquid crystal director is helically rotated for each smectic layer in the state where an external electric field does not work. be called. Further, even in the chiral smectic C phase, the antiferroelectric liquid crystal faces the direction in which the liquid crystal directors face each other. Since the liquid crystal composed of these chiral smectic C phases has an asymmetric carbon in the molecular structure and is spontaneously polarized by this, the liquid crystal molecules are rearranged in a direction determined by the spontaneous polarization Ps and the external electric field E. Optical properties are controlled. In this embodiment and the like, the ferroelectric liquid crystal is taken as an example of the liquid crystal layer and the optical axis deflecting element (and the optical path deflecting element) will be described. However, the same applies to the case of the antiferroelectric liquid crystal. Can do.

  The operation of the optical axis deflection element of the present invention will be described with reference to FIG. 2A and 2B schematically show the electric field direction and the tilt direction of the liquid crystal molecules in an arbitrary divided region (for example, the divided region (1) in FIG. 1) of the optical axis deflecting element 10 shown in FIG. It is shown in. 2A and 2B show a state in which the side on which the liquid crystal molecules are drawn wide is inclined to the upper side of the drawing and the side in which the width is drawn is inclined to the lower side of the drawing. In addition, the spontaneous polarization of the liquid crystal (denoted by the symbol Ps) is indicated by an arrow. As shown in FIGS. 2A and 2B, when the direction of the electric field in the divided region is reversed, the direction of the tilt angle of the substantially vertically aligned liquid crystal molecules is reversed. Here, the relationship between the electric field application direction and the tilt direction of the liquid crystal molecules in the case where the spontaneous polarization Ps is positive is illustrated. Here, when the direction of the tilt angle is reversed, it is considered that it moves in a virtual cone-shaped plane as shown in the lower perspective views of FIGS. 2 (a) and 2 (b). Note that the model of the liquid crystal molecular arrangement of the chiral smectic C phase (the model of the helical structure change by the electric field) is the same as the example shown in FIG.

  Next, a case where an electric field is applied to the liquid crystal layer 15 and a case where it is removed will be described. As described above, when an electric field is applied to the chiral smectic C phase forming a helical structure in the absence of an electric field, the electric drive for aligning the liquid crystal molecules by the interaction between the dipole and the electric field caused by the carbonyl group in the liquid crystal molecules Since the force works, the liquid crystal realignment time when an electric field is applied is relatively short. In the case of a general ferroelectric liquid crystal, the alignment change of the liquid crystal is completed in sub-milliseconds to several tens of microseconds depending on the electric field strength. On the other hand, when the electric field is removed, the liquid crystal layer 15 tries to return to the initial alignment state under no electric field. About slow. The present invention utilizes the fact that the realignment time of the liquid crystal layer 15 is sufficiently slow when the electric field is turned off. That is, as shown in FIGS. 1 and 3, the effective region of the optical axis deflecting element 10 is divided into a plurality of regions, and one or more divided electrodes can be applied independently to each region. 17 is arranged.

  Here, in order to simplify the explanation, FIG. 3 shows that one divided electrode 17 is arranged at the center of the effective area (effective width L) of the optical axis deflecting element 10 and is divided into two areas having a width of L / 2. This is an example of division. As an optical axis deflecting device, a voltage applying means comprising a switch unit 19 (switches S1 to S4) and a power source 18 is connected to each electrode 16a, 17, 16b of the optical axis deflecting element 10, and each electrode is selectively connected. The voltage can be applied. For example, as shown in FIG. 3A, a voltage is temporarily applied between the first electrodes that generate an electric field in the first region on the left side of the diagram (between the electrode 16a and the divided electrode 17). After the optical axis of the liquid crystal layer 15a is tilted and the desired optical axis tilt state is reached, the voltage in the first region is removed, and immediately thereafter, as shown in FIG. After a voltage is temporarily applied between the second electrodes that generate an electric field (between the divided electrode 17 and the electrode 16b), the optical axis of the liquid crystal layer 15b in the second region is tilted, and a desired optical axis tilt state is achieved. To remove the voltage in the second region. Thereafter, before the time when the optical axis tilt state of the first region returns to the initial state due to re-orientation of the liquid crystal layer 15a, it is temporarily the same as the previous time again between the first electrodes (between the electrodes 16a and the divided electrodes 17). By applying a polar electric field, the optical axis tilt state of the liquid crystal layer 15a in the first region can be maintained. By repeating this operation between the first region and the second region, the tilted state of the optical axis can be kept substantially uniform throughout the effective region within a certain period.

In the figure, for simplification of explanation, a DC power supply is shown as the power supply 18 and only an electric field in one direction is applied, but a rectangular wave AC voltage or the like as shown in FIG. 2 is applied. It is also possible to reverse the electric field direction using an alternating current power source.
In FIG. 3, only the function of the switch unit 19 for switching the voltage application state of the electrodes 16a, 16b, and 17 is described in a simplified manner. However, the switches S1 to S4 for realizing the above function have a withstand voltage. It is preferable to use one that is high and capable of high-speed operation. For this reason, it is more preferable to use a photocoupler or the like that can perform a high-speed switching operation with light and has a higher withstand voltage than a relay switch or the like. In addition, since the operation of the photocoupler can be controlled by an external electric signal, a voltage can be selectively applied to each electrode of the optical axis deflecting element according to the electric signal, and each divided region of the liquid crystal layer 15 can be applied. The applied electric field can be easily controlled, and the tilt direction of the optical axis of the liquid crystal layer in each divided region can be easily controlled. The same applies to the switches described in the following embodiments.

  Conventionally, as shown in FIG. 4, a power source is connected to the electrodes 6a and 6b provided at both ends of the element, and a parallel electric field is applied to the entire effective area width of the element. When an electric field strength E = 150 V / mm is applied to an element having a width L of 42 mm, a high voltage of 6.3 kV is applied, so that safety measures such as prevention of discharge from the periphery of the element are required. On the other hand, in the optical axis deflecting element 10 having the configuration shown in FIGS. 1 and 3, the effective area of the optical axis deflecting element 10 is spatially and electrically divided into two, and about several milliseconds for each divided area. By alternately applying the short-time electric field, it is possible to substantially maintain the liquid crystal alignment state when the electric field is applied to the entire effective region. In this method, since the width of the divided region to which the electric field is applied can be set to 21 mm, which is half, even when the same electric field strength E = 150 V / mm is applied, the applied voltage value itself should be set to half, 3.15 kV. Can do. Therefore, the overall cost of the apparatus can be reduced by simplifying measures for preventing discharge and noise from occurring in the optical axis deflecting apparatus and reducing the size of the power supply.

  In the above embodiment, the effect is described for the configuration in which the effective area of the optical axis deflecting element 10 is divided into two. However, according to the technical idea of the present invention, the present invention can be implemented without being limited to two. That is, in the second embodiment of the present invention, the effective area width of the optical axis deflecting element 10 is L, the voltage value when the voltage is applied to the entire effective area width is V, and the average value applied at this time is When the parallel electric field strength is E and the constant electric field application period is T, the effective region is divided into N (N is an integer of 2 or more) in the electric field application direction, and 1 or more so that the electric field can be applied. In order to apply an average parallel electric field strength E to L / N which is the width of each divided region, the voltage value of V / N is temporarily set to a time within T / N. By applying and temporally switching the region to which the voltage is temporarily applied, the parallel electric field strength E can be applied to the entire effective region evenly over time. FIG. 5 shows an example of a configuration in which two divided electrodes 17a and 17b are arranged so that the effective region of the optical axis deflecting element 10 is divided into three in the electric field application direction and an electric field can be applied. Yes. The switch unit 19 constituting the voltage application means is composed of a large number of switches (photocouplers, etc.) S1 to S10 so that a voltage can be selectively applied to the electrodes 16a, 17a, 17b, 16b.

Here, as an example, it is assumed that the effective axis width L = 42 mm, the electric field strength E = 150 V / mm, the frequency f = 60 Hz, and the tilt direction of the optical axis is changed in the vertical direction.
In the case of the element having the conventional configuration shown in FIG. 4, a rectangular wave AC power source or the like may be connected to the electrodes 6a and 6b at both ends of the element, and the direction of the electric field may be reversed at a desired frequency. Driving is performed such that the upward period T = 8.33 msec and the downward period T = 8.33 msec. On the other hand, when the effective area is divided into three as in the element having the configuration shown in FIG. 5, V / N = 2.1 kV is sequentially applied to each divided area every time T / N = 2.78 msec. When the application of the three regions is completed once, an AC operation can be performed by similarly applying a reverse polarity voltage. Further, even when the effective region is spatially divided into three, the electric field application time to each divided region is further shortened to T / 6 (= T / 2N) or T / 9 (= T / 3N), It is preferable to repeat during the period T. Here, the electric field application time to each divided region is preferably at least longer than the maximum alignment time of the liquid crystal layer when the electric field is ON. For example, assuming that the response time of the liquid crystal is 1 msec, it works well if T / 6 = 1.39 msec divided by 6 in time, but good if T / 6 = 0.93 msec divided by 9 in time. I cannot expect it to work. However, such an optimal division time range varies depending on properties of the liquid crystal material, electric field strength, driving frequency, and the like.

  Here, FIG. 6 shows an outline of the drive timing at the time of AC drive of the optical axis deflection element. Here, for the sake of simplification of explanation, the optical axis deflection element 10 having a configuration in which the effective area shown in FIG. 3 is divided into two parts will be described as an example. 6A and 6B, the vertical axis represents the tilt angle of the optical axis in each divided region, and the horizontal axis represents time. 6A shows the state of the first region (divided region (1)), and FIG. 6B shows the state of the second region (divided region (2)). In the figure, the electric field application timing in each divided region is indicated by an arrow. 6C shows a change in one cycle (frequency f = 60 Hz, 1 cycle = 16.77 msec) of the power supply voltage (rectangular wave AC voltage), and FIG. 6D shows each switch S1 of the switch unit 19. ~ Represents the ON / OFF switching timing of S4.

  First, as soon as an electric field + E is applied to the divided region (1), the inclination angle of the optical axis becomes + θ and becomes saturated. After application for a certain period, the electric field in the divided region (1) is turned off, and the electric field is switched to the electric field application in the divided region (2). Up to this point, since only the divided region (1) is operating, the “initial operation” state is not uniform as a whole. When the tilt angle of the optical axis of the split region (2) is saturated to + θ, the tilt angle starts to decrease in the split region (1) due to the non-electric field reorientation of the liquid crystal layer. Since it is applied, the tilt angle is maintained at approximately + θ on a time average. Similarly in the divided region (2), the inclination angle of the optical axis is maintained at + θ. By using a liquid crystal material in which realignment of the liquid crystal layer is slow when there is no electric field, it is possible to maintain a “constant tilt angle” state in which both regions are simultaneously + θ.

  Next, the timing for reversing the tilt angle of the optical axis will be described. In FIG. 6A, first, an inversion electric field -E is applied to the divided region (1) to saturate the tilt angle of the divided region (1) to -θ. During this time, the divided region (2) is in a state where the tilt angle is approximately + θ under no electric field. That is, this state is a “mismatch” state in which the tilt directions of the optical axes are different from those of the divided regions (1) and (2). Thereafter, if the inversion electric field -E is applied also to the divided region (2), this inconsistency state is immediately eliminated, and at the same time, a "constant tilt angle" state in which -θ is obtained. The period of the mismatch state is not preferable for the optical axis deflecting element of the present invention when the entire element is averaged and used. Therefore, it is preferable to set the period of the mismatch state as short as possible. Since the period of the inconsistency coincides with one electric field application time, it is preferable to increase the number of time division of voltage application as described above. Here, FIG. 7 shows an example of the drive timing when the number of time divisions of voltage application is increased. In this way, the ON / OFF switching operation of the switches S1 to S4 of the switch unit 19 is made faster. Thus, by increasing the number of time divisions of voltage application, the non-matching period can be set short.

  As yet another embodiment, as shown in FIG. 8, the electric field application time can be set short only when the electric field is reversed. That is, as shown in FIG. 8, at the timing of reversing the direction of the parallel electric field of the entire effective region by the ON / OFF switching operation of the switches S1 to S4 of the switch unit 19, the direction of the optical axis is reversed. Is set shorter than the temporary electric field application time for maintaining the optical axis in one direction. In FIG. 8, the time of the “mismatch” state can be shortened by setting the application time during the “reversal operation” to about ¼ as compared with the time of application at the “constant tilt angle” state. it can. Therefore, it is possible to set a long state in which the optical axis tilt directions of the entire effective region coincide with each other, thereby improving temporal and spatial uniformity of the optical characteristics. Here, the electric field application time during the reversal operation is preferably at least longer than the maximum alignment time of the liquid crystal layer when the electric field is ON.

  By the way, in the above-mentioned optical axis deflection element, the divided electrode provided in the effective region is a metal film. However, the metal film has a problem that light transmitted through the effective region is shielded. In particular, when the number of divided regions is increased, the number of divided electrodes also increases, so that a decrease in transmittance as a whole element becomes a problem. Therefore, in still another embodiment of the present invention, like the optical axis deflecting element 10 shown in FIG. 9, the divided electrodes in the effective region are the line-shaped transparent electrodes 20 formed on the substrate surface. By using the line-shaped transparent electrode 20 in this way, it is possible to prevent the transmitted light from being blocked and to improve the light transmittance. As the transparent electrode material, it is preferable to use a vapor-deposited film or a sputtered film of an oxide semiconductor such as ITO (indium-containing tin oxide) or ZnO. Alternatively, a material in which these oxide semiconductor fine particles are dispersed in a resin may be applied and formed.

  Next, a case where the effective area of the optical axis deflecting element is designed to be larger will be described. As the element width increases, the applied voltage value simply increases in order to obtain a constant electric field. Therefore, by dividing the effective area and driving sequentially in time as in the present invention, the applied voltage can be reduced by reducing the width of electric field driving at a time. Therefore, it is conceivable that the number of divisions is further increased as the area of the device is further increased. However, the number of divisions N is 2 due to the complexity of the voltage changeover switch and the restriction due to the reorientation time when the liquid crystal layer is in the absence of an electric field. To about 4 are preferable. In practice, it may be preferable to set the number of divisions N as small as possible as long as the upper limit of the high voltage used safely in the apparatus allows. In this case, the width of the divided area is set to be relatively wide. However, when the width of the divided area is about several millimeters to 10 millimeters, electrodes are formed at both ends of the divided area as shown in FIGS. If only the voltage is applied with the arrangement, another problem that the electric field is not effectively applied to the central portion of the divided region may occur. That is, when the electrode interval in the direction parallel to the substrate surface of the element is increased, the electric field is concentrated in a range of several millimeters near the electrode, and the electric field uniformity in the divided region may be deteriorated.

  Therefore, in yet another embodiment of the present invention, like the optical axis deflection element 30 shown in FIGS. 10 and 11, an electrode and a divided electrode for applying a parallel electric field in the effective region are formed on the substrate surface. A plurality of transparent line electrodes 21, a dielectric layer 22 is formed between the surface of the transparent line electrode group and the liquid crystal layer 15, and each transparent line electrode group is electrically connected in series by a resistor 24. A potential difference is generated between the two transparent line electrodes 21 at positions corresponding to the width of the divided area (1) or the divided area (2) (that is, positions at both ends of the divided area (1) or the divided area (2)). It was set as the structure applied. In this example, the electrodes at both ends of the effective area of the element are also the transparent line electrodes 21 formed on the substrate surface, so that the spacers 23 are disposed at both ends of the liquid crystal layer 15.

  As a material constituting the transparent line electrode 21, it is preferable to use a vapor deposition film or a sputtered film of an oxide semiconductor such as ITO or ZnO. Alternatively, a material in which these oxide semiconductor fine particles are dispersed in a resin may be applied and formed. The width of the transparent line electrode is preferably as narrow as possible, but is practically processed to a width of about 10 μm. The pitch between the line electrodes is preferably about several tens of μm to several hundreds of μm, but is set in relation to the dielectric constant and thickness of the dielectric layer described later.

  As the dielectric layer 22, a highly transparent material such as glass or resin can be used. In particular, it is preferable to use a material having no birefringence. The thickness of the dielectric layer 22 is preferably about several μm to several hundred μm, but is set in relation to the pitch of the transparent line electrodes 21. The dielectric layer 22 is attached to the substrate surface on which the transparent line electrode 21 is formed by a transparent adhesive. When the dielectric layer 22 is formed thin, it may be polished to a desired thickness after bonding the thick dielectric layer. The adhesive preferably has a high transmittance and a relatively large refractive index, which is close to the refractive index of the transparent electrode material. Furthermore, since the liquid crystal alignment films 13 and 14 are formed on the dielectric layer 22, heat resistance of about 100 ° C. to 200 ° C. that can withstand heat treatment in the alignment film forming process is also required. Moreover, when the dielectric layer 22 and the alignment films 13 and 14 are resin, it is necessary to optimize the coating solvent of both. An optical axis deflecting element as shown in FIG. 10 is produced by filling the dielectric layer 22 and the alignment films 13 and 14 as upper and lower substrates and filling the liquid crystal layer 15 between the substrates. At this time, the positions of the transparent line electrodes 21 on the upper and lower substrates are the same in FIG. 10, but they may be combined so that the transparent line electrodes 21 on the upper and lower substrates are alternately arranged when the element is viewed from above.

Next, in order to electrically connect each transparent line electrode 21 in series, a resistor 24 is formed as shown in FIG. The resistor 24 may be any resistor that expresses a desired resistance value and can be formed on the transparent line electrode. A material having a surface resistance of 1 × 10 ⁷ Ω / □ or more is preferable in order that the resistor 24 functions stably, does not break down, and prevents adverse effects on liquid crystal characteristics due to excessive heat generation of the resistor. . Specifically, chromium oxide, tin oxide, antimony oxide, zinc oxide, ATO (antimony-containing tin oxide), or a coating-type material in which these fine particles are dispersed in a resin can be used. As a forming method on the transparent line electrode, there are a deposition method, a sputtering method, a coating type resistor material, a spin coating method, a flexographic printing method, a printing method such as screen printing, and a jetting method such as a nozzle or an ink jet method. Can be used. Depending on the forming method, it is necessary to mask other than the resistor forming portion. The formation width of the resistor on the transparent line electrode is slightly different depending on the resistor material, but is preferably about 1 mm to 5 mm. In addition to forming the resistor 24 on the substrate as shown in FIG. 11, each transparent line electrode is extended using a flexible substrate and connected to a resistor material or resistor array on another substrate other than the element. May be. In FIG. 11, the three transparent line electrodes 21 at both ends and the center of the element are set to be connectable to the power source 18 via the switch unit 19 and are divided into two regions (1) and (2). Therefore, the driving method of this element may be the same as the driving method described with reference to FIGS.

  In the optical axis deflecting element 30 described above, the periodic structure by the transparent line electrode 21 is formed in the effective region. Therefore, when the refractive index difference between the transparent electrode material and the adhesive increases, the periodic structure by the transparent line electrode becomes a diffraction grating. In some cases, a diffraction phenomenon occurs.

  Therefore, in still another embodiment of the present invention, like the optical axis deflection element 40 shown in FIGS. 12 and 13, the transparent line electrodes 21 are arranged only at both ends and division positions of the effective area of the element, and within the effective area. A transparent resistor layer 25 is formed on the substrate surface. In this configuration, since there is no periodic structure in the effective region, the diffraction phenomenon of transmitted light can be prevented. Further, a relatively uniform parallel electric field can be formed by the transparent resistor layer 25 without providing a dielectric layer. Furthermore, in order to average the electric field disturbance caused by local resistance unevenness and defects of the transparent resistor layer 25, a dielectric similar to that shown in FIGS. 10 and 11 is interposed between the transparent resistor layer 25 and the liquid crystal layer 15. Layer 22 may be formed.

  As a material for forming the transparent resistor layer 25, a resin dispersion film of conductive powder such as tin oxide or indium oxide can be used. In the case of a resin dispersion film, it can be formed by spin coating or various printing methods. Further, a light transmissive metal oxide can also be used as the transparent resistor film. Examples of the metal oxide include tin oxide, zinc oxide, cadmium oxide, indium oxide, lead oxide, gallium oxide as binary compounds, magnesium / indium oxide, gallium / indium oxide as ternary compounds, Zinc / indium oxide, zinc / tin oxide, or the like can be used. Among these, additives such as antimony, fluorine, tin indium oxide, antimony, gallium, boron and the like in zinc oxide may be added. If a physical deposition method is used as a method for forming a metal oxide layer, it is possible to grow a film from the atomic / molecular level at a relatively low temperature, so that the degree of freedom of substrate selection is wide and it covers a large area. A film having a uniform thickness and composition can be obtained. As the physical deposition method, a vacuum deposition method, an ion plating method, a sputtering method and the like are widely used industrially.

The function of the transparent resistor layer 25 of the present embodiment is to form a desired potential gradient along the substrate surface, and is preferably used under the condition that the amount of heat generated when energized is small. Therefore, it is preferable to use a high-resistance transparent resistor having a surface resistance value of about 1 × 10 ⁸ Ω / □ or more. When considering the volume resistance value corresponding to this, when the film thickness of the resistor is 0.1 μm, it is 10 ³ Ωcm or more, when the film thickness is 1 μm, it is 10 ⁴ Ωcm or more, and when the film thickness is 10 μm, it is 10 ⁵ Ωcm. The above is preferable. At this time, the time constant of the resistor is not more than microseconds, and is a value that causes no practical problem in applications where the voltage is switched at a cycle of several hundred microseconds.
In FIG. 13, the three transparent line electrodes 21 constituting the electrodes at both ends of the effective region and the central divided electrode are set to be connectable to the power source 18 through the switch unit 19, and two divided regions (1), It is divided into (2). Therefore, the driving method of this element may be the same as the driving method described with reference to FIGS.

Although the optical axis deflection operation can be performed substantially uniformly over the entire effective area by the above configuration, the uniformity of the optical axis may be impaired when the vicinity of the divided electrodes is observed in detail. For example, the case where the line-shaped transparent electrode 20 is used as a division | segmentation electrode like FIG. 9 is demonstrated.
FIG. 20 is a diagram showing an electric field application state of the element similar to that in FIG. 9, and the alignment film is omitted. A broken line in the center of the figure indicates that the divided electrode 20 of the upper substrate 12 and the divided electrode 20 of the lower substrate 11 are electrically connected. 20A shows a state in which a voltage is applied to the left divided region, and FIG. 20B shows a state in which a voltage is applied to the right divided region. Here, a configuration diagram of the voltage application state changeover switch and description of its operation are omitted. The divided electrode 20 has a width of at least about 10 μm, but no electric field is generated within the electrode width because the divided electrode 20 has the same potential within the electrode width. Therefore, a portion where the electric field is reduced is generated in the liquid crystal layer near the electrode. When the positions of the divided electrodes 20 of the upper and lower substrates 11 and 12 coincide with the light transmission direction (up and down direction on the paper surface) as shown in FIG. 20, the hatched portions in the center of FIG. 20 are (a) and (b). In both electric field application states, since it is adjacent to the non-electric field region, it tends to always be a low electric field portion. In this low electric field portion, the tilt angle of the optical axis is locally reduced, which causes a decrease in the uniformity of the entire effective region. In particular, a light beam perpendicularly incident on the low electric field region is easily affected by this portion.

Therefore, in the present invention, as shown in FIG. 21, the low electric field region can be generated obliquely with respect to the thickness direction of the liquid crystal layer by arranging the upper and lower divided electrodes 20 so as to be displaced. Therefore, the light beam perpendicularly incident on the substrate in the vicinity of the divided electrodes passes through the low electric field region only partially in the thickness direction of the liquid crystal layer 15, so that the entire liquid crystal layer thickness becomes the low electric field region as shown in FIG. It will be less affected than the case.
Note that the same effect can be obtained even when the transparent resistor layer 25 shown in FIGS. 12 and 13 is provided in the configuration in which the positions of the divided electrodes are shifted.

  When transparent line electrode groups (multiple transparent line electrodes 21) as shown in FIG. 10 and FIG. 11 are arranged as the divided electrodes, the transparent line electrodes of the upper substrate 12 connected as divided electrodes as shown in FIG. What is necessary is just to set so that the position of 21 and the transparent line electrode 21 of the lower substrate 11 may differ. Thereby, the low electric field region generated inside the liquid crystal layer can be formed obliquely. Therefore, the light beam perpendicularly incident on the substrate in the vicinity of the divided electrodes passes through the low electric field region only partially in the thickness direction of the liquid crystal layer 15, so that the entire liquid crystal layer thickness becomes the low electric field region as shown in FIG. It will be less affected than the case.

  However, in FIG. 21 and FIG. 22, when the positional deviation of the divided electrodes between the upper substrate 12 and the lower substrate 11 increases, an electric field component is generated in the thickness direction of the liquid crystal layer 15, and the optical axis tilt direction at the electric field application portion is It will change. FIG. 23 shows a model diagram of the electric field direction in the vicinity of the divided electrode in FIG. Here, the electric field in the liquid crystal layer is considered by a simple model. The potential of the electrode set as the divided electrode is V1, the deviation amount of the divided electrodes on the upper and lower substrates is ΔX, the distance between the electrodes in the element thickness direction is ΔZ, and the potential of the upper line electrode corresponding to the position of the lower divided electrode is V2. Further, it is assumed that the potential of the lower line electrode corresponding to the upper divided electrode is substantially equal to V1. Strictly speaking, it is preferable to estimate the internal electric field distribution from the dielectric constants of the substrate, the dielectric layer, and the liquid crystal layer, but it is assumed here that the dielectric constants of all the materials are the same for simplification. Further, when the electric field direction in the liquid crystal layer is inclined by 45 degrees or more, the vertical alignment property of the liquid crystal layer is deteriorated, and an alignment result such as cloudiness is generated.

Therefore, in the present invention, the deviation amount ΔX of the divided electrodes is set to be smaller than the distance ΔZ between the electrodes. In the model of FIG. 23, the electric field at point A in the liquid crystal layer is a combination of the horizontal electric field Ex and the thickness direction electric field Ez. If the potential at point A is VA and the potential at point B is VB,
Ex = (VA−VB) / ΔX
Ez = (VA−V1) / (ΔZ / 2)
Where VB is almost equal to V1,
Ex × ΔX = Ez × (ΔZ / 2)
It becomes a relationship.
Here, in order to set the inclination direction of the electric field E at point A within 45 degrees, Ex> Ez may be satisfied, and (ΔZ / 2)> ΔX from the above-described relational expression. That is, by setting the deviation amount ΔX of the divided electrodes to be smaller than a half value of the distance ΔZ between the electrodes, it is possible to prevent occurrence of liquid crystal alignment defects due to an oblique electric field.

  In the above configuration, the position of the divided electrode is fixed, but in the other configuration of the present invention, the position of the electrode that functions as the divided electrode is changed according to the region to which the electric field is applied. For this purpose, as shown in FIG. 24, the divided electrode that divides the effective region into a plurality is composed of at least a pair of line-shaped electrodes 20a and 20b, and the electric field applied in time to each divided region is a pair of line-shaped electrodes 20a. , 20b, the electric field application periods are set to overlap in the corresponding liquid crystal layer. For example, in FIG. 24A, an electric field is applied to the left side region of the element by applying a voltage between the upper and lower divided electrodes 20a and the leftmost electrode of the pair of divided electrodes 20a and 20b near the center. In (b), an electric field is applied to the right side region of the element by applying a voltage between the upper and lower divided electrodes 20b on the left side of the pair of divided electrodes 20a and 20b near the center and the right end electrode of the element. In this case, an electric field is always applied between the divided electrodes near the center, and a region that becomes a low electric field at the end of the divided region moves in accordance with the switching of the region. Can be prevented from occurring. In this case, since the width between the electrodes is set wider than that in FIG. 20, it is necessary to set a large voltage value for obtaining the same electric field, but the distance between the pair of divided electrodes is larger than the width of the divided region. This is not a problem for practical use. Even in the configuration using the transparent line electrode group (a large number of transparent line electrodes 21) as shown in FIG. 22, the same effect can be obtained by changing the line electrode 21 selected as the divided electrode as shown in FIG. .

In the above embodiment, a voltage is applied only between the corresponding electrodes in order to generate an electric field in a certain divided region, and the electrodes corresponding to the other divided regions are electrically floated. In such a case, an electric field in the reverse direction may be generated in another divided region adjacent to the electric field application region. This reverse electric field changes the alignment state of the liquid crystal layer, which should be essentially in the absence of an electric field.
Therefore, in still another embodiment of the present invention, as shown in FIG. 14, the voltage value between the electrodes is controlled so that the corresponding electrodes have the same potential except in the divided region in the electric field application state. That is, ON / OFF of the switches S1 to S4 of the switch unit 19 is controlled so that the electrodes in the divided regions where no electric field is applied have the same potential. Thereby, it is possible to reliably prevent the generation of an unnecessary electric field that disturbs the tilt state of the optical axis of the liquid crystal layer in the divided region that should be in an electric field-free state.

  Next, in still another embodiment of the present invention, the optical axis deflecting element having the above-described configuration is used as an optical path deflecting element. As shown in FIGS. 15 (a) and 15 (b), the optical axis deflecting element is used. Incident light to the element is linearly polarized, and the plane of polarization of the linearly polarized light is set in a direction perpendicular to the direction of application of the parallel electric field in the element, thereby shifting the position of the outgoing optical path with respect to the incident optical path in parallel. Can do. In addition, an optical path deflecting device that deflects the optical path of light in accordance with an electrical signal is configured by connecting the voltage applying means including the power source 18 and the switch unit 19 to the optical path deflecting element to control the shift of the optical path. Is done.

Here, FIGS. 15A and 15B schematically show the alignment state of the liquid crystal molecules of the optical path deflecting element formed of the optical axis deflecting element, and the vertical alignment film, the spacer, the electrode, etc. are illustrated. It is omitted. In FIG. 15, for the sake of convenience, a voltage is applied in the front and back direction of the paper, and the electric field acts in the front and back direction of the paper. The direction of the electric field is switched by a voltage applying means (not shown) corresponding to the intended tilt direction of the optical axis. When an electric field to the front side of the paper is applied as shown in FIG. 15A, if the spontaneous polarization of the liquid crystal molecules is positive, the number of molecules in which the liquid crystal director is inclined to the upper right of the figure increases, and the average as the liquid crystal layer The optical axis also tilts in the upper right direction of the figure and functions as a birefringent plate. Above the threshold electric field above which the helical structure of the chiral smectic C phase can be solved, all the liquid crystal directors exhibit a tilt angle θ and become birefringent plates with the optical axis inclined upward at an angle θ. Therefore, the linearly polarized light incident as the extraordinary light from the left side of the figure is shifted in parallel to the upper side of the figure. Here, when the refractive index in the major axis direction of the liquid crystal molecules is ne, the refractive index in the minor axis direction is no, and the thickness (gap) of the liquid crystal layer is d, the shift amount S is expressed by the following formula 1 ( For example, refer nonpatent literature 1).
S = [(1 / no) ² − (1 / ne) ² ] sin (2θ) × d
÷ [2 ((1 / ne) ² sin ² θ + (1 / no) ² cos ² θ)] Equation 1

Similarly, when the applied voltage to the electrode is reversed as shown in FIG. 15B and an electric field toward the back of the paper is applied, the liquid crystal director tilts to the lower right in the figure if the spontaneous polarization of the liquid crystal molecules is positive. The optical axis functions as a birefringent plate inclined downward at an angle θ. Therefore, the linearly polarized light incident as the extraordinary light from the left side of the figure is shifted in parallel to the lower side of the figure. In addition, an optical path deflection amount of 2S can be obtained by reversing the electric field direction.
Therefore, the emission position of the light beam can be switched by switching the electric field direction and switching the tilt direction of the optical axis. This provides an optical path deflecting device that can be driven with a relatively small applied voltage with respect to a large effective area.

  Next, still another embodiment of the present invention will be described with reference to FIG. This embodiment shows an example in which the optical path deflecting device (optical axis deflecting device) having the above-described configuration is applied to the optical path deflecting means of the image display device 80. In FIG. 16, reference numeral 81 in the figure denotes a light source in which LED lamps are arranged in a two-dimensional array, and in the traveling direction of light emitted from the light source 81 toward the screen 86, a diffusion plate 82, a condenser lens 83, an image A transmissive liquid crystal panel 84 as a display element and a projection lens 85 as an optical member for observing the image pattern are sequentially arranged. Reference numeral 87 denotes a light source drive unit for the light source 81, and 88 denotes a drive unit for the transmissive liquid crystal panel 84.

  Here, on the optical path between the transmissive liquid crystal panel 84 and the projection lens 85, optical path deflecting means 89 that functions as a pixel shift element is interposed and connected to the drive unit 90. As such an optical path deflecting unit 89, an optical path deflecting device (optical axis deflecting device) having the above-described configuration is used.

  The illumination light that is controlled by the light source drive unit 87 and emitted from the light source 81 becomes illumination light that is made uniform by the diffuser plate 82, and is controlled by the condenser lens 83 in synchronization with the illumination light source by the liquid crystal drive unit 88 and is transmissive. The liquid crystal panel 84 is critically illuminated. The illumination light spatially modulated by the transmissive liquid crystal panel 84 enters the optical path deflecting device 89 as image light, and the optical path deflecting device 89 shifts the image light by an arbitrary distance in the pixel arrangement direction. This light is magnified by the projection lens 85 and projected onto the screen 86.

  Here, by displaying on the transmissive liquid crystal panel 84 an image pattern in which the display position is shifted in accordance with the deflection of the optical path for each of the plurality of subfields obtained by temporally dividing the image field by the optical path deflecting device 89. The apparent number of pixels of the transmissive liquid crystal panel 84 can be multiplied and displayed. Thus, the amount of shift by the optical path deflecting device 89 is set to ½ of the pixel pitch because the image multiplication is performed twice as much as the pixel arrangement direction of the transmissive liquid crystal panel 84. By correcting the image signal for driving the transmissive liquid crystal panel 84 according to the shift amount by the shift amount, an apparently high-definition image can be displayed. At this time, since the optical axis deflecting device as in each of the above-described embodiments is used as the optical path deflecting device 89, the use efficiency of light is improved, and the observer is brighter without increasing the load on the light source. High quality images can be provided.

  The image display device is not limited to the type that uses the transmissive liquid crystal panel 84 as the image display element, and similarly applies to a type that uses the reflective liquid crystal panel 91, such as the image display device 94 shown in FIG. it can. Reference numeral 92 denotes a drive unit for the reflective liquid crystal panel 91. In the case of this configuration, a polarization beam splitter (PBS) 93 is added as compared with the image display device 80 shown in FIG. 16, and the light from the illumination system is folded back to the reflective liquid crystal panel 91 side by the PBS 93, and the optical path deflecting device. The reflection type liquid crystal panel 91 is irradiated through 89. The illumination light incident on the reflective liquid crystal panel 91 undergoes spatial modulation corresponding to the image while being reflected by the reflective liquid crystal panel 91 and is emitted as image light. Thereafter, the light enters the optical path deflecting device 89, and the optical path deflecting device 89 shifts the image light by a predetermined distance in the pixel arrangement direction. The subsequent route is the same as that of the image display apparatus shown in FIG.

  Next, specific examples and comparative examples of the present invention will be described.

[Example 1]
First, an optical axis deflection element 10 having a configuration as shown in FIG. 1 is created. A chromium electrode line (divided electrode 17) having a width of 5 μm and a length of 8 mm or 7 mm was formed in the short side direction of the center surface of two types of glass substrates having a thickness of 1.1 mm and a size of 10 mm × 8 mm and 5 mm × 7 mm. . One end of the electrode line on the large substrate was expanded to several millimeters for wiring connection. The vertical (homeotropic) alignment films 13 and 14 of the polyimide compound having a thickness of 0.06 μm were formed on the surface on which the electrodes were formed. As the polyimide alignment film, a polyamic acid solution was applied by spin coating, and a polyimide film was obtained by imidization treatment by heat treatment at about 180 ° C. A cell was produced by sandwiching an aluminum sheet having a thickness of 80 μm, a width of about 1 mm, and a length of 8 mm outside the effective area of both ends of the element as spacer members / electrodes 16a and 16b, with the two substrates 11 and 12 facing each other. . At this time, the chrome electrode lines within the effective area of the upper and lower substrates were laminated so as to overlap each other when viewed from above, and the chrome electrodes of the upper and lower substrates were connected with a small amount of conductive paste interposed therebetween. While the cell was heated to about 90 ° C., ferroelectric liquid crystal (CS1024 manufactured by Chisso) was injected into the space between the substrates by a capillary method. After cooling, it was sealed with an adhesive, and the optical axis deflecting element 10 having a thickness of the liquid crystal layer 15 of 80 μm and an effective area of 8 mm × 7 mm square was produced.

From this optical axis deflecting element 10, the aluminum sheets of the spacer members and electrodes 16a and 16b at both ends and the enlarged portion of the chromium electrode (divided electrode) 17 on the large substrate are exposed. An optical axis deflecting device that was divided into two effective areas of 4 mm width was obtained by connecting to the power source 18 via the switch unit 19 in a state where application is possible.
The response time when the electric field of E = 150 V / mm is turned on by the voltage applying means to the liquid crystal layer 15 of the optical axis deflecting element 10 constituting this optical axis deflecting device is sufficiently fast as 0.5 msec, and realignment when the electric field is turned off. The time is very slow, about several hundred msec.

  The inclination angle of the optical axis of the optical axis deflection element was measured by conoscopic observation. For the measurement, a white laser was used as a light source, and a beam expander, a polar laser, and a microscope objective lens with NA = 0.75 were passed in this order to irradiate the effective area of the device. A conoscopic image is obtained by projecting the transmitted light that has passed through the liquid crystal layer of the element onto a transmissive screen surface through an analyzer. The conoscopic image was taken with a CCD camera or a high-speed camera, and the tilt angle of the optical axis was measured by analyzing the position of the cross-shaped shadow of the conoscopic image. As shown in FIG. 3, a DC voltage of 600 V was alternately applied to the effective divided region (1) and the effective divided region (2) every 5 msec for 1 second in 100 cycles. When the state of the inclination angle for 1 second was analyzed, it was confirmed that the inclination angle of 25 degrees was maintained substantially uniformly in both effective regions.

[Comparative Example 1]
As Comparative Example 1, an optical axis deflecting element having an effective area of 8 mm × 7 mm square and having an arrangement as shown in FIG. 4 was prepared in the same manner as in Example 1 except that a chromium electrode (divided electrode) was not provided at the center of the effective area. did. A DC voltage of 1200 V was applied to the electrodes 6a and 6b at both ends of the element for 1 second so that the same parallel electric field strength E = 150 V / mm as in Example 1 was applied. As a result, an inclination angle of 25 degrees was shown near the electrodes at both ends, but about 20 degrees near the center. This indicates that a sufficient electric field is not applied to the central portion even if a voltage is simply applied to both ends of a relatively wide element. In addition, it was necessary to apply a voltage twice as high as that in Example 1.

[Example 2]
Next, an optical axis deflecting element 30 having a configuration as shown in FIGS. 10 and 11 is prepared. 420 ITO transparent line electrodes 21 having a width of 10 μm and a length of 45 mm were formed in parallel at a pitch of 100 μm on the surfaces of glass substrates 11 and 12 having a thickness of 1.1 mm and a size of 50 mm × 50 mm. The transparent line electrodes 21 at both ends are formed to have a wide width of 4 mm and a length of 50 mm, and the single transparent line electrode 21 at the center has a length of 50 mm, and one end of the transparent line electrode 21 is widened to several millimeters for wiring extraction. Formed. The effective area of the transparent electrode line group is about 42 mm × 40 mm square, and glass having a thickness of 150 μm is pasted thereon as a dielectric layer 22 with an ultraviolet curable adhesive. The thickness of the adhesive was about 10 μm. A portion of the width 5mm transparent line electrode 21 is exposed, the surface resistance as a resistor 24 is deposited by sputtering a 1 × 10 ⁸ Ω / □ CrSiO film.

  As shown in the cross-sectional view of the element shown in FIG. 10, the transparent line electrodes 21 are embedded in the transparent glass substrates 11 and 12, and each transparent line electrode 21 is formed of a resistor film as shown in FIG. 24 were connected in series. On the surface of the substrate, vertical (homeotropic) alignment films 13 and 14 of a polyimide compound having a thickness of 0.06 μm were formed. As the polyimide alignment film, a polyamic acid solution was applied by spin coating, and a polyimide film was obtained by imidization treatment by heat treatment at about 180 ° C. The 80 μm spacer sheet 23 was sandwiched outside the effective area, the two substrates 11 and 12 were opposed, and the transparent electrode lines within the effective area of the upper and lower substrates were bonded to each other when viewed from above. While the cell was heated to about 90 ° C., ferroelectric liquid crystal (CS1024 manufactured by Chisso) was injected into the space between the substrates by a capillary method. After cooling, it was sealed with an adhesive, and an optical axis deflecting element 30 having a liquid crystal layer 15 thickness of 80 μm and an effective area of about 42 mm × 40 mm square was produced.

The transparent line electrodes at both ends and the transparent line electrode at the center of the optical axis deflecting element 30 are connected to the power source 18 via the switch unit 19 so that an electric field can be applied as shown in FIG. Got the device.
The above elements were driven at the voltage application timing as shown in FIG. 6 using a pulse generator and a high-voltage amplifier for the power supply unit 18 and a high voltage changeover switch combined with a photocoupler for the switch unit 19. The voltage of the rectangular wave AC power source was ± 3.15 kV and the frequency was 60 Hz. Since the divided region width is 21 mm, the electric field strength of each divided region is E = 150 V / mm. One period of 60 Hz driving is 16.67 msec, and the period of one-side polarity is T = 8.33 msec. At the drive timing as shown in FIG. 6, the electric field application time for each divided region is 1.85 msec. In the steady driving state except the initial operation state, a positive polarity voltage is applied twice in each region (1.85 × 4 = 7.4 msec), and the operation at the time of voltage reversal is as short as 0.52 msec. A negative polarity electric field is applied once (0.46 × 2 = 0.93 msec), and the period up to this time is set to T = 8.33 msec of a half cycle. By applying the voltage for a short time in this way, the mismatch time in the optical axis direction of the two regions accompanying the voltage inversion described above can be shortened to about 0.46 msec. This time is comparable to the original electric field response time of the liquid crystal layer, and it can be determined that there is no practical problem.

  In this way, when the conoscopic image was observed in a state where the optical axis reversal operation was repeated at 60 Hz for the entire device, the reversal operation of the tilt angle of the optical axis of about ± 25 degrees was confirmed almost uniformly over the entire 42 mm width. . However, strictly speaking, the inclination angle around the central division was observed to be slightly smaller. When a He—Ne laser beam was incident on this element, a slight diffraction pattern was observed in the emitted light. This is considered to be due to the periodic phase modulation due to the refractive index difference between the ITO transparent electrode and the adhesive.

[Example 3]
Next, an optical axis deflecting element 40 having a configuration as shown in FIGS. 12 and 13 is prepared. Wide transparent line electrodes 21 having a width of 4 mm and a length of 50 mm are formed at both ends of glass substrates 11 and 12 having a thickness of 1.1 mm and a size of 50 mm × 50 mm with a spacing of 42 mm, and a width of 10 μm is formed at the center thereof. A single transparent line electrode 21 having a length of 50 mm was formed. One end of the central transparent line electrode was formed to be several millimeters wide for wiring extraction. A transparent resistor film 25 was formed on the substrate in the range as shown in FIG. As the transparent resistor film 25, a tin oxide film having a thickness of 0.1 μm was formed by a high frequency magnetron sputtering method. A sintered body of tin oxide was used as a target. During sputtering, argon gas and oxygen were flowed so that the flow rate ratio was about 1: 4. At this time, the substrate is not heated or cooled. The volume resistivity of the tin oxide film formed under these conditions is as high as about 5 × 10 ³ Ωcm, and the surface resistivity when the thickness is 0.1 μm is 5 × 10 ⁸ Ω / □. The visible light transmittance of this tin oxide film was 90% or more. Each transparent line electrode 21 was connected in series by a transparent resistor film 25. On the surface of the substrate, vertical (homeotropic) alignment films 13 and 14 of a polyimide compound having a thickness of 0.06 μm were formed. As the polyimide alignment film, a polyamic acid solution was applied by spin coating, and a polyimide film was obtained by imidization treatment by heat treatment at about 180 ° C. The 80 μm spacer sheet 23 was sandwiched outside the effective area, the two substrates were opposed to each other, and the transparent electrode lines within the effective area of the upper and lower substrates were bonded to each other when viewed from above. While the cell was heated to about 90 ° C., ferroelectric liquid crystal (CS1024 manufactured by Chisso) was injected into the space between the substrates by a capillary method. After cooling, it was sealed with an adhesive to produce an optical axis deflecting element 40 having a liquid crystal layer 15 thickness of 80 μm and an effective area of about 42 mm × 40 mm square.

The transparent line electrodes at both ends and the transparent line electrode at the center of the optical axis deflecting element 40 are connected to the power source 18 through the switch unit 19 so that an electric field can be applied as shown in FIG. Got the device.
A conoscopic image was observed by applying the same voltage pattern as in Example 2 using a high voltage changeover switch in which a pulse generator and a high-voltage amplifier were used for the power supply unit 18 and a photocoupler was used for the switch unit 19. An inversion operation of the tilt angle of the optical axis of about ± 25 degrees was confirmed substantially uniformly over the entire width. However, in this example as well, when observed strictly, the inclination angle around the central divided portion was observed to be slightly smaller. Further, when a He—Ne laser beam was incident on this element, a diffraction pattern as observed in Example 2 was not observed.

[Example 4]
Using the same optical axis deflecting element 40 as in Example 3, the high-voltage switch unit 19 using a combination of photocouplers was improved so that the electrode pairs other than the electric field application region are made conductive and have the same potential as shown in FIG. As a result, the slight decrease in the inclination angle around the central divided portion, which was observed in Example 3, was not observed. This is presumably because the region adjacent to the divided region to which the electric field is applied is surely maintained in the non-electric field state, and the tilt angle of the optical axis when the non-electric field is applied is maintained large.

[Example 5]
In Example 2, the single transparent line electrode 21 in the center is 50 mm in length, and one end of the transparent line electrode 21 is widened to several millimeters for taking out the wiring. When the upper and lower substrates 11 and 12 are overlapped, Although the transparent line electrodes for extraction are arranged so as to overlap each other, in Example 5, when the upper and lower substrates 11 and 12 are stacked, the position of the transparent line electrode 21 for extraction is shifted by one by one above and below. The position of the electrode for taking out the substrate was set. Other configurations were the same as in Example 2 to produce an optical axis deflecting element as shown in FIG. In this element, the deviation amount of the divided electrodes on the upper and lower substrates is ΔX of 100 μm, and the distance ΔZ between the upper and lower electrodes through the dielectric layer and the liquid crystal layer is about 400 μm. Conditions for preventing electric field generation (ΔZ / 2)> ΔX
Meet.

  Similar to the second embodiment, the inversion operation of the optical axis was confirmed by a conoscopic image using the power supply unit 18 and the high voltage changeover switch 19. As a result, the inclination of the optical axis was approximately uniform about ± 25 degrees across the entire 42 mm width. The corner reversal operation was confirmed. In addition, the phenomenon in which the inclination angle around the central divided portion observed in Example 2 was observed to be slightly small was not observed. However, when the element was placed in the crossed Nicols of the polarizing plate and observed with a microscope, light leakage considered to be slightly caused by light scattering was observed near the center. This is considered to be caused by slight light scattering because the liquid crystal layer is distorted by the influence of the oblique electric field generated in the vicinity of the divided electrodes, but it was in a range where there is no practical problem.

[Example 6]
In Example 2, the single transparent line electrode 21 in the center is 50 mm in length, and one end of the transparent line electrode 21 is widened to several millimeters for taking out the wiring. When the upper and lower substrates 11 and 12 are overlapped, Although the transparent line electrodes for extraction are arranged so as to overlap each other, in Example 6, the two transparent line electrodes 20a and 20b at the center of each of the upper and lower substrates 11 and 12 are set to 50 mm, and one end of each wiring is taken out. Expanded for use. Other configurations were the same as in Example 2, and an optical axis deflection element as shown in FIG. 24 was prepared.
Moreover, although the power supply unit 18 and the high voltage changeover switch 19 are used as in the second embodiment, a switch (not shown) is added so that the position of the divided electrode with respect to the divided region can be switched. By adding this switch, the voltage application operation as shown in FIGS. 24A and 24B becomes possible. Although the width of the divided region has increased to 21. 1 mm in Example 6 compared to 21 mm in Example 2, there is no practical problem with the reduction in the electric field strength associated therewith.

  As in Example 2, the inversion operation of the optical axis was confirmed with a conoscopic image, and the inversion operation of the inclination angle of the optical axis of about ± 25 degrees was confirmed almost uniformly over the entire 42 mm width. In addition, the phenomenon in which the inclination angle around the central divided portion observed in Example 2 was observed to be slightly small was not observed. Furthermore, although the element was placed in the crossed Nicols of the polarizing plate and observed with a microscope, light leakage near the center as observed in Example 5 was not observed. This is presumably because the generation of the oblique electric field generated in the vicinity of the divided electrodes is eliminated.

[Example 7]
Next, an image display apparatus having a configuration similar to that of FIG. 16 was produced. As the image display element 84, three 0.9 inch diagonal XGA (1024 × 768 dots) polysilicon TFT liquid crystal panels were used. FIG. 16 illustrates the case where the number of liquid crystal panels is one, but the light from the three liquid crystal panels is synthesized by a synthesis prism (not shown) and projected by one projection lens 85. The pixel pitch of the liquid crystal panel 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, the frame frequency of image display is 60 Hz, and the subfield frequency for double pixel multiplication by pixel shift is 120 Hz which is double. Each of the three liquid crystal panels is illuminated with light obtained by color separation of RGB three-color light sources or white light sources using a prism or filter, and a full-color image is displayed by combining the images of the respective colors with a combining prism (not shown). In addition, by making the polarization direction of the light emitted from the liquid crystal panel 84 coincide with the tilt direction of the optical axis of the optical axis deflecting device 89, the optical path shift function can be exhibited and the optical path can be shifted in the polarization direction. When the optical axis deflection apparatus of Example 4 is used as an optical path deflection apparatus, the optical path shift amount is about 9 μm, which is ½ of the pixel pitch of the liquid crystal panel. Further, in order to ensure the degree of polarization of incident light to the optical path deflecting device, a linearly polarizing plate was provided on the incident surface side of the device.

  The voltage applied to the optical path deflecting device and the operation timing were set to ± 3.15 kV and the frequency was 60 Hz as in Example 4. In synchronization with the switching timing of the optical path shift position, the subfield image displayed on the image display element was rewritten at T = 8, 33 msec, so that a high-definition image in which the number of apparent pixels was doubled could be displayed. . At this time, the intensity of the parallel electric field applied to the entire liquid crystal layer was 150 V / mm and the switching time of the optical path was about 0.5 msec, and a sufficient pixel shift effect and light utilization efficiency were obtained.

  The optical axis deflecting element and the optical path deflecting element according to the present invention, and the optical axis deflecting apparatus and the optical path deflecting apparatus using them can be suitably used for image display devices such as a projection display and a head mounted display. It can also be used for an optical writing device of an image forming apparatus such as a copying machine, a laser printer, a laser plotter, and a laser facsimile. In addition, it can be used for an image input device, a laser measuring device, and the like.

It is a schematic sectional drawing of the optical axis deflection | deviation element which shows one Embodiment of this invention. It is a figure which shows typically the relationship between the electric field direction applied to an optical axis deflection element, and the orientation direction of a liquid crystal molecule. It is a figure which shows one Embodiment of this invention, Comprising: It is explanatory drawing of the structural example of the optical axis deflection | deviation apparatus using the optical axis deflection element shown in FIG. 1, and a voltage application method. It is explanatory drawing of the structural example and voltage application method of the conventional optical axis deflection | deviation apparatus. It is a figure which shows another embodiment of this invention, Comprising: It is explanatory drawing of the structural example of the optical axis deflection | deviation apparatus using an optical axis deflection element, and a voltage application method. It is a figure which shows an example of the drive timing of the optical-axis deflection | deviation element of this invention. It is a figure which shows another example of the drive timing of the optical-axis deflection | deviation element of this invention. It is a figure which shows another example of the drive timing of the optical-axis deflection | deviation element of this invention. It is a figure which shows another embodiment of this invention, Comprising: (a) is a schematic sectional drawing of an optical axis deflection element, (b) It is a schematic plan view of an optical axis deflection element. It is a schematic sectional drawing of the optical axis deflection | deviation element which shows another embodiment of this invention. FIG. 11 is a diagram showing still another embodiment of the present invention, in which (a) is a schematic plan view of an optical axis deflection device using the optical axis deflection element shown in FIG. 10, and (b) a line electrode of the optical axis deflection element. It is a schematic sectional drawing of the direction parallel to. It is a schematic sectional drawing of the optical axis deflection | deviation element which shows another embodiment of this invention. FIG. 11 is a diagram showing still another embodiment of the present invention, in which (a) is a schematic plan view of an optical axis deflection device using the optical axis deflection element shown in FIG. 10, and (b) a line electrode of the optical axis deflection element. It is a schematic sectional drawing of the direction parallel to. It is a figure which shows another embodiment of this invention, Comprising: It is explanatory drawing of the structural example of the optical axis deflection | deviation apparatus using an optical axis deflection element, and a voltage application method. FIG. 6 is a diagram illustrating the principle of an optical axis deflection operation and an optical path deflection operation of a liquid crystal layer when the optical axis deflection element of the present invention is used as an optical path deflection element. It is a figure which shows another embodiment of this invention, Comprising: It is a schematic block diagram which shows an example of the image display apparatus using an optical path deflection | deviation apparatus. It is a figure which shows another embodiment of this invention, Comprising: It is a schematic block diagram which shows another example of the image display apparatus using an optical path deflection apparatus. It is a schematic sectional drawing of the optical path deflection element which shows an example of a prior art. It is a figure which shows the model (model of the helical structure change by an electric field) of the liquid crystal molecular arrangement | sequence of a chiral smectic C phase. It is a conceptual diagram which shows the electric field application state in the vicinity of the divided | segmented boundary of the optical axis deflection | deviation element of this invention. It is explanatory drawing of the position shift effect of the division | segmentation electrode of the optical axis deflection | deviation element of this invention. It is explanatory drawing of the shift effect of the setting position of the division | segmentation electrode of the optical axis deflection | deviation element of this invention. It is a conceptual diagram which shows the electric field in the vicinity of the division | segmentation electrode of the optical axis deflection | deviation element of FIG.22 (b). It is explanatory drawing of the effect by the time change of the division | segmentation electrode position of the optical axis deflection | deviation element of this invention.

Explanation of symbols

10, 30, 40: Optical axis deflection element (optical path deflection element)
DESCRIPTION OF SYMBOLS 11, 12: Substrate 13, 14: Alignment film 15: Liquid crystal layer 16a, 16b: Electrode 17, 17a, 17b: Divided electrode 18: Power supply 19: Switch part 20: Transparent electrode 21: Transparent line electrode 22: Dielectric layer 23 : Spacer 24: Resistor 25: Transparent resistor layer 80, 94: Image display device 81: Light source 82: Diffuser plate 83: Condenser lens 84: Transmission type liquid crystal panel (image display element)
85: Projection lens 86: Screen 87: Light source drive unit 88: Drive unit of transmissive liquid crystal panel 89: Optical path deflecting device (optical path deflecting means)
90: Drive unit of optical path deflecting device 91: Reflective liquid crystal panel (image display element)
92: Drive unit of reflective liquid crystal panel 93: Polarizing beam splitter (PBS)

Claims (29)

A pair of transparent substrates, a liquid crystal layer capable of forming a homeotropically aligned chiral smectic C phase filled between the pair of substrates, and arranged at least on both ends of the liquid crystal layer in a direction parallel to the substrate surface In an optical axis deflection element having an electrode that generates an electric field (hereinafter referred to as a parallel electric field),
An optical axis deflection element, wherein an effective area between the electrodes is divided into a plurality of areas, and one or more divided electrodes are arranged so that a parallel electric field can be independently applied to each area. The optical axis deflecting element according to claim 1, wherein
The width of the effective area between the electrodes is L, the voltage value when a voltage is applied to the entire width of the effective area is V, the average electric field strength applied at this time is E, and the constant electric field application period is T Then, the effective region is divided into N pieces (N is an integer of 2 or more) in the electric field application direction, and one or more divided electrodes are arranged so that a parallel electric field can be applied. Axial deflection element. The optical axis deflecting element according to claim 1 or 2,
The optical axis deflecting element, wherein the divided electrode in the effective area is a line-shaped transparent electrode formed on a substrate surface corresponding to both ends of each divided area. The optical axis deflecting element according to claim 1 or 2,
The divided electrode in the effective area is composed of a large number of transparent line electrodes formed on the substrate surface, and a dielectric layer is formed between the surface of the transparent line electrode group and the liquid crystal layer, and each transparent line An optical axis deflecting element, wherein the electrodes are electrically connected in series by a resistor. The optical axis deflecting element according to claim 1 or 2,
The electrodes and the divided electrodes in the effective area are line-shaped transparent electrodes formed on the substrate surface corresponding to both ends of each divided area, and a transparent resistor layer is formed on the substrate surface. An optical axis deflecting element characterized by comprising: The optical axis deflection element according to claim 3 or 5,
The optical axis deflection element, wherein the line-shaped transparent electrodes formed on a pair of substrate surfaces are arranged at different positions on a projection plane with respect to a light transmission direction. The optical axis deflecting element according to claim 4, wherein
Of the multiple transparent line electrodes, the positions of the transparent line electrodes that are directly connected to the power source and function as the divided electrodes on both substrates are set to different positions on the projection plane with respect to the light transmission direction. An optical axis deflection element. The optical axis deflecting element according to claim 6 or 7,
With respect to the positional relationship of the divided electrodes arranged at different positions or intersecting with each other, the maximum deviation amount in the parallel electric field direction on the projection plane with respect to the light transmission direction is ΔX, and the liquid crystal layer thickness direction An optical axis deflecting element characterized in that (ΔZ / 2)> ΔX is set, where ΔZ is ΔZ. In the optical axis deflection element according to any one of claims 1 to 8,
The divided electrode that divides the effective region into a plurality is composed of at least a pair of line-shaped electrodes, and the electric field applied in order to each divided region in time is the electric field application period in the liquid crystal layer corresponding to the pair of line-shaped electrodes. The optical axis deflecting element is set so as to overlap each other. An optical path deflecting element that deflects an optical path of light according to an electrical signal,
The optical axis deflecting element according to any one of claims 1 to 9, wherein incident light to the optical axis deflecting element is linearly polarized light, and a polarization plane of the linearly polarized light is applied in a direction of applying a parallel electric field in the element. An optical path deflecting element characterized by shifting the position of the outgoing optical path with respect to the incident optical path in parallel by setting in a direction orthogonal to the optical path. A pair of transparent substrates, a liquid crystal layer capable of forming a homeotropically aligned chiral smectic C phase filled between the pair of substrates, and arranged at least on both ends of the liquid crystal layer in a direction parallel to the substrate surface An optical axis deflection element having an electrode for generating an electric field (hereinafter referred to as a parallel electric field);
Using voltage applying means for applying a voltage to the electrode of the optical axis deflection element;
In the optical axis deflection method for switching the orientation direction of the liquid crystal molecules by switching the electric field direction of the optical axis deflection element and switching the tilt direction of the optical axis with respect to the layer normal of the liquid crystal layer, and switching the outgoing optical path for incident light,
The optical axis deflection element according to any one of claims 1 to 9 is used as the optical axis deflection element, and a voltage is selectively applied to each electrode of the optical axis deflection element by the voltage application unit. An optical axis deflection method. The optical axis deflection method according to claim 11, wherein
The effective area width of the optical axis deflecting element is L, the voltage value when a voltage is applied to the entire effective area width is V, the average parallel electric field strength applied at this time is E, and the constant electric field application period Where T is T, one or more polarization electrodes are arranged so that an electric field can be applied by dividing the effective region into N (N is an integer of 2 or more) with respect to the direction of electric field application. In order to apply an average parallel electric field strength E to L / N, which is the width of V / N, a voltage value of V / N is temporarily applied for a time within T / N, and a voltage is temporarily applied. A method of deflecting an optical axis, wherein the parallel electric field strength E is uniformly applied to the entire effective area when time averaged by switching the areas to be performed in time sequence. The optical axis deflection method according to claim 11, wherein
The effective region of the optical axis deflecting element is divided into at least a first region and a second region, and a voltage is temporarily applied between the first electrodes that generate an electric field in the first region, so that the optical region of the liquid crystal layer in the first region After the axis is tilted and the desired optical axis tilt state is reached, the voltage in the first region is removed, and then a voltage is temporarily applied between the second electrodes that immediately generate an electric field in the second region. The optical axis of the liquid crystal layer in the two regions is tilted, the voltage in the second region is removed after the desired optical axis tilt state is reached, and the time before the optical axis tilt state of the first region returns to the initial state is reached. In addition, by temporarily applying an electric field of the same polarity or reverse polarity to the first electrode again between the first electrodes, the operation of maintaining the optical axis tilt state of the liquid crystal layer in the first region or switching to the reverse polarity tilt state. Are sequentially performed between the first area and the second area, so that the The optical axis deflection method characterized by maintaining the inclined state of the optical axis substantially uniformly as a whole Oite effective area. The optical axis deflection method according to claim 11, wherein
The effective region of the optical axis deflecting element is divided into N (N is an integer of 2 or more) from the first region to the Nth region, and a voltage is temporarily applied between the first electrodes that generate an electric field in the first region. Then, the optical axis of the liquid crystal layer in the first region is tilted, and after the desired optical axis tilt state is reached, the voltage in the first region is removed, and then an electric field is immediately generated in the second region between the second electrodes. A voltage is temporarily applied to tilt the optical axis of the liquid crystal layer in the second region, and after the desired optical axis tilt state is reached, the voltage in the second region is removed to the Nth region. By applying an electric field of the same polarity or reverse polarity as the previous time temporarily between the first electrodes again before the time when the optical axis tilt state of the first region returns to the initial state, the liquid crystal of the first region The operation of maintaining the tilted state of the optical axis of the layer or switching to the tilted state of reverse polarity is performed in the first region. By sequentially performed between the first N region, it is an optical axis deflection method characterized by maintaining the inclined state of the optical axis substantially uniformly as a whole effective region within a certain period. The optical axis deflection method according to any one of claims 11 to 14,
At the timing of reversing the direction of the parallel electric field of the entire effective area of the optical axis deflecting element, a temporary electric field application time for reversing the direction of the optical axis is temporarily used to maintain the optical axis in one direction. An optical axis deflection method characterized in that the optical axis deflection time is set shorter than an appropriate electric field application time. In the optical axis deflection method according to any one of claims 11 to 15,
A split electrode for applying a parallel electric field in an effective area of the optical axis deflecting element comprises a plurality of transparent line electrodes formed on a substrate surface, and a dielectric is formed between the surface of the transparent line electrode group and the liquid crystal layer. A body layer is formed, each transparent line electrode is electrically connected in series by a resistor, and a potential difference is applied between two transparent line electrodes at a position corresponding to the width of the divided region. Optical axis deflection method. The optical axis deflection method according to any one of claims 11 to 16,
In a state where a voltage is applied between the corresponding electrodes in order to generate an electric field in a certain divided region of the optical axis deflecting element, between the corresponding electrodes so that an unnecessary electric field is not generated in the adjacent divided region. A method of deflecting an optical axis, characterized in that the voltage value between the electrodes is controlled so as to have the same potential.   The optical axis deflection method according to any one of claims 11 to 17, wherein incident light to the optical axis deflection element is linearly polarized light, and a polarization plane of the linearly polarized light is applied in a direction of applying a parallel electric field in the element. An optical path deflection method characterized by shifting the position of the outgoing optical path with respect to the incident optical path in parallel by setting in a direction orthogonal to the incident optical path. A pair of transparent substrates, a liquid crystal layer capable of forming a homeotropically aligned chiral smectic C phase filled between the pair of substrates, and arranged at least on both ends of the liquid crystal layer in a direction parallel to the substrate surface An optical axis deflection element having an electrode for generating an electric field (hereinafter referred to as a parallel electric field);
Voltage application means for applying a voltage to the electrode of the optical axis deflection element,
In the optical axis deflecting device for switching the orientation direction of the liquid crystal molecules by switching the electric field direction of the optical axis deflecting element and switching the tilt direction of the optical axis with respect to the layer normal of the liquid crystal layer, and switching the outgoing optical path for incident light,
The optical axis deflection element according to any one of claims 1 to 9, wherein the voltage application means includes means for selectively applying a voltage to each electrode of the optical axis deflection element. An optical axis deflecting device comprising: The optical axis deflecting device according to claim 19,
The effective area width of the optical axis deflecting element is L, the voltage value when a voltage is applied to the entire effective area width is V, the average parallel electric field strength applied at this time is E, and the constant electric field application period Where T is T, one or more polarization electrodes are arranged so that an electric field can be applied by dividing the effective region into N (N is an integer of 2 or more) with respect to the direction of electric field application. In order to apply an average parallel electric field strength E to L / N, which is the width of V / N, a voltage value of V / N is temporarily applied for a time within T / N, and a voltage is temporarily applied. An optical axis deflecting device characterized in that the parallel electric field strength E is uniformly applied to the entire effective area when time averaged by switching the areas to be performed in time sequence. The optical axis deflecting device according to claim 19,
The effective region of the optical axis deflecting element is divided into at least a first region and a second region, and a voltage is temporarily applied between the first electrodes that generate an electric field in the first region, so that the optical region of the liquid crystal layer in the first region After the axis is tilted and the desired optical axis tilt state is reached, the voltage in the first region is removed, and then a voltage is temporarily applied between the second electrodes that immediately generate an electric field in the second region. The optical axis of the liquid crystal layer in the two regions is tilted, the voltage in the second region is removed after the desired optical axis tilt state is reached, and the time before the optical axis tilt state of the first region returns to the initial state is reached. In addition, by temporarily applying an electric field of the same polarity or reverse polarity to the first electrode again between the first electrodes, the operation of maintaining the optical axis tilt state of the liquid crystal layer in the first region or switching to the reverse polarity tilt state. Are sequentially performed between the first area and the second area, so that the Oite optical axis deflection device, characterized in that to maintain the inclination of the optical axis substantially uniformly as a whole effective area. The optical axis deflecting device according to claim 19,
The effective region of the optical axis deflecting element is divided into N (N is an integer of 2 or more) from the first region to the Nth region, and a voltage is temporarily applied between the first electrodes that generate an electric field in the first region. Then, the optical axis of the liquid crystal layer in the first region is tilted, and after the desired optical axis tilt state is reached, the voltage in the first region is removed, and then an electric field is immediately generated in the second region between the second electrodes. A voltage is temporarily applied to tilt the optical axis of the liquid crystal layer in the second region, and after the desired optical axis tilt state is reached, the voltage in the second region is removed to the Nth region. By applying an electric field of the same polarity or reverse polarity as the previous time temporarily between the first electrodes again before the time when the optical axis tilt state of the first region returns to the initial state, the liquid crystal of the first region The operation of maintaining the tilted state of the optical axis of the layer or switching to the tilted state of reverse polarity is performed in the first region. The N region is sequentially carried out that between the optical axis deflection apparatus characterized by maintaining substantially uniform inclination of the optical axis as a whole effective region within a certain period of time. The optical axis deflecting device according to any one of claims 19 to 22,
At the timing of reversing the direction of the parallel electric field of the entire effective area of the optical axis deflecting element, a temporary electric field application time for reversing the direction of the optical axis is temporarily used to maintain the optical axis in one direction. An optical axis deflecting device characterized in that the optical axis deflecting device is set shorter than an appropriate electric field application time. The optical axis deflecting device according to any one of claims 19 to 23,
A split electrode for applying a parallel electric field in an effective area of the optical axis deflecting element comprises a plurality of transparent line electrodes formed on a substrate surface, and a dielectric is formed between the surface of the transparent line electrode group and the liquid crystal layer. A body layer is formed, each transparent line electrode is electrically connected in series by a resistor, and a potential difference is applied between two transparent line electrodes at a position corresponding to the width of the divided region. Optical axis deflection device. The optical axis deflecting device according to any one of claims 19 to 24,
In a state where a voltage is applied between the corresponding electrodes in order to generate an electric field in a certain divided region of the optical axis deflecting element, between the corresponding electrodes so that an unnecessary electric field is not generated in the adjacent divided region. An optical axis deflecting device that controls the voltage value between the electrodes so as to have the same potential. In an optical path deflecting device that deflects the optical path of light in response to an electrical signal,
11. An optical path deflecting device comprising: the optical path deflecting element according to claim 10; and voltage applying means for selectively applying a voltage to each electrode of the optical path deflecting element in accordance with the electrical signal. In an optical path deflecting device that deflects the optical path of light in response to an electrical signal,
26. The optical axis deflecting device according to any one of claims 19 to 25, wherein incident light to the optical axis deflecting element is linearly polarized light, and a polarization plane of the linearly polarized light is applied in a direction of applying a parallel electric field in the element. An optical path deflecting device characterized by shifting the position of the outgoing optical path with respect to the incident optical path in parallel by setting in a direction perpendicular to the optical path. An image display element in which a plurality of pixels capable of controlling light according to image information are two-dimensionally arranged, a light source and an illumination device that illuminate the image display element, and an image pattern displayed on the image display element In an image display device having an optical device, display driving means formed by a plurality of subfields obtained by dividing an image field in time, and optical path deflecting means for deflecting an optical path of light emitted from each pixel,
An image display apparatus comprising the optical path deflecting device according to claim 26 or 27 as the optical path deflecting unit. The image display device according to claim 28, wherein
By displaying on the image display element an image pattern corresponding to a state in which the display position is shifted according to the deflection state of the optical path for each subfield by the optical path deflecting device, the apparent number of pixels of the image display element is increased. An image display device characterized by being displayed in a doubled size.

Images