JP2006267907A - Optical deflecting element and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical deflecting element which has simple constitution and can be easily manufactured and can efficiently perform optical deflection. <P>SOLUTION: The optical deflecting element 1 has a pair of transparent substrates 3, a spacer 4, a plurality of transparent line electrodes 5, a dielectric layer 6, a liquid crystal layer 7 which can form a chiral smectic C phase, and a resistance film 8 which electrically connects a group of the plurality of line electrodes 5 in series. The group of line electrodes 5 and the resistance film 8 are made of the same material and R<SB>R</SB>>R<SB>E</SB>is satisfied, where R<SB>R</SB>represents the surface resistivity of the resistance film 8 and R<SB>E</SB>represents the surface resistivity of the line electrodes 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention includes an optical deflection element (including the concept of an optical deflection device) that changes the direction of light by an electric signal, and an image display device (including a concept of an electronic display device) such as a projection display and a head-mounted display having the optical deflection element. )

Japanese Patent Laid-Open No. 2002-328402 describes a configuration in which a liquid crystal composed of a chiral smectic C phase having homeotropic alignment is filled between a pair of transparent substrates and an electric field is applied to the liquid crystal.
As the liquid crystal provided between the substrates, a liquid crystal composed of a chiral smectic C phase is used. Therefore, this type of optical deflecting element has a problem. In addition, optical noise can be improved, and dullness in response when smectic A liquid crystal or nematic liquid crystal is used as the liquid crystal can be improved, and high-speed response is possible.
In JP-A-2003-0985502, a plurality of line electrode groups having a line shape are formed on two transparent substrates, and the positions of the line electrodes on each transparent substrate are alternately arranged. There is described a configuration in which different values are set alternately and stepwise between the transparent substrates so that the applied voltage increases or decreases stepwise toward the line electrode at the other end. With such a configuration, generation of a reverse electric field is prevented, and a light deflection effect can be obtained even in the vicinity of the line electrode by generating a potential difference between the line electrode on the opposite transparent substrate even in the vicinity of the line electrode.

In Japanese Patent Application Laid-Open No. 2004-286938, a plurality of line electrodes are connected by resistors, and the resistor is made of a substance having a higher resistance than the line electrodes, thereby reducing the number of wires to the outside of the transparent substrate. Reduce the size of the transparent substrate and apply a voltage so that the potential changes linearly to the liquid crystal layer between the two transparent substrates. And a configuration for driving the deflection angle of the optical deflection apparatus is described.
As specific resistors, Cr—SiO, SiC, SnO ₂ doped with Sb or P or the like, which requires a process such as sputtering or vapor deposition, is described, and a resistance value is within a specified range. It is described.

JP 2002-328402 A Japanese Patent Laid-Open No. 5-216075 JP-A-9-133904 JP 2004-286938 A JP 2004-286938 A JP 2003-0985502 A

In Patent Document 4, a transparent conductive film such as ITO (tin-containing indium oxide) is used as a line electrode group, and an example in which SnO ₂ doped with Cr—SiO, SiC, P, or Sb is used as a resistance film. Are listed.
However, since the line electrode and the resistance film are composed of different layers, it is necessary to perform film formation processes such as sputtering and vapor deposition twice using different materials.
In addition, experiments and considerations by the present inventors have revealed that a very large contact resistance occurs between the line electrode and the resistance film depending on the combination of materials and film formation conditions. An increase in contact resistance is a problem because it causes a deterioration in potential gradient accuracy and a decrease in electric field generation efficiency.

  The main object of the present invention is to provide an optical deflecting element that is simple in structure, easy to manufacture, and capable of efficiently deflecting light, and an image display apparatus including the same.

If the line electrode group and the resistance film are formed of the same material, the cost of the material can be reduced. In addition, by forming these layers as a single layer without stacking them, the film forming process can be completed once, and the manufacturing process can be simplified. In the case of stacking as in the conventional case, the electrical contact may deteriorate due to impurities entering between the two layers or the interface state changing. Can be avoided.
The present invention has been embodied under such an eye,
According to the first aspect of the present invention, a pair of transparent substrates, a plurality of transparent line electrodes provided on at least one substrate, a liquid crystal layer provided between the substrates, and the line electrode group are electrically connected. In the optical deflection element having a resistance film connected to the line electrode, the line electrode and the resistance film are made of the same material, and the respective functions of the both are separated by making the surface resistivity of the both different. Here, “transparent” includes the concept of light transmission (hereinafter the same).
Further, it is intended to enable production with a small number of materials and a simple manufacturing process.

According to the second aspect of the present invention, a pair of transparent substrates, a plurality of transparent line electrodes disposed substantially parallel to a desired optical path shift direction in a region including the optical paths on the substrates, A liquid crystal layer that forms a chiral smectic C phase within the interval of the substrate, and a resistance film that electrically connects the transparent line electrode group in series, wherein the resistance film and the line electrode are made of the same material, When the surface resistivity of the resistance film is R _R and the surface resistivity of the line electrode is R _E , R _R > R _E is _satisfied .
Further, it is intended to enable production with a small number of materials and a simple manufacturing process.

According to a third aspect of the present invention, in the optical deflection element according to the first or second aspect, the resistance film and the line electrode group are a single film formed simultaneously.
Here, it is another object to obtain an efficient optical deflection element with a simple manufacturing process.

According to a fourth aspect of the present invention, in the optical deflection element according to the first, second, or third aspect, the resistance film and the line electrode group are made of an oxide material.
Here, it is another object to obtain an efficient optical deflection element with a simple manufacturing process.

The invention according to claim 5 is the optical deflection element according to claim 4, wherein the oxide material is tin-containing indium oxide.
Another object of the present invention is to provide an optical deflection element that operates stably and is easy to manufacture.

In the invention according to claim 6, an image display element in which a plurality of pixels capable of controlling light according to image information is two-dimensionally arranged, a light source and an illumination device for illuminating the image display element, and the image display element An optical member for observing the displayed image pattern, display driving means formed by a plurality of subfields obtained by temporally dividing the image field, and an optical deflection element for deflecting the optical path of the emitted light from each pixel are provided. In the image display device that displays the image pattern in which the display position is shifted in accordance with the deflection of the optical path for each sub-field, thereby multiplying and displaying the apparent number of pixels of the image display element, The optical deflection element is an optical deflection element according to claim 1, 2, 3, 4 or 5.
It is another object of the present invention to provide an apparatus that can display an apparently high-definition image using an image display element having a small number of pixels.

According to the invention described in claim 1 or 2, the number of types of materials can be reduced compared to a method of forming a line electrode group and a resistance film by laminating films made of different materials, and a simpler process. Can be manufactured. Therefore, the manufacturing cost can be reduced.
According to the third aspect of the invention, the film forming process for forming the resistance film and the line electrode group can be performed only once. Further, unlike the case of using a laminated structure, the influence of impurities entering between the two layers and the change in the interface state are eliminated, so that the electrical contact between the resistance film and the line electrode can be made relatively good. By suppressing unnecessary contact resistance, efficient light deflection can be achieved.

According to the fourth aspect of the present invention, the resistivity of the oxide film can be changed greatly depending on conditions at the time of film formation and post-treatment after film formation. Therefore, if the resistance film and the line electrode group are films made of a translucent oxide, R _R > R _E can be easily _achieved, and the difference in resistivity can be greatly increased, so that unevenness of the electric field can be suppressed. As a result, the electric field generation efficiency is increased, and an efficient optical deflection element can be obtained.
According to the invention described in claim 5, among the translucent oxides, ITO has a relatively good electrical property and is easily processed such as etching. Is easy to form.
According to the sixth aspect of the present invention, a high-quality image display device can be obtained by using a light deflection element that can be manufactured in a simple process and operates stably.

Hereinafter, a first embodiment of the present invention will be described with reference to FIG. In this specification, the “light deflecting element” means that the optical path of light is deflected by an external electric signal, that is, the outgoing light is shifted in parallel with respect to the incident light, or is rotated with a certain angle, Alternatively, it means an optical element capable of switching the optical path by combining both.
In this description, the magnitude of the shift with respect to the light deflection caused by the parallel shift is referred to as “shift amount”. The “light deflection device” means a device that includes such a light deflection element and deflects the optical path of light.
The “pixel shift element” means an image display element in which a plurality of pixels that can control light according to image information is two-dimensionally arranged, a light source that illuminates the image display element, and an image displayed on the image display element. An optical member for observing the pattern, and a light deflecting means for deflecting the optical path between the image display element and the optical member for each of a plurality of subfields obtained by dividing the image field in time. Means light deflecting means in an image display device that displays an image pattern in which the display position is shifted according to the deflection of the optical path for each field, thereby increasing the apparent number of pixels of the image display element. To do.
Therefore, basically, it can be said that the optical deflection element and the optical deflection device defined above can be applied as the optical deflection means.

FIG. 1 shows the configuration of the optical deflection element 1. (A) is a front view, (b) is sectional drawing of the element in the broken line 2 of (a).
In this optical deflection element 1, a pair of transparent substrates 3 are provided so as to face each other with a spacer 4 interposed therebetween. A plurality of transparent line electrodes 5 are formed on the inner surface (opposing surface) of each substrate 3. A dielectric layer 6 is disposed on the inner surface of the group of line electrodes 5, and an alignment film (not shown) is formed on the inner surface of the dielectric layer 6.
A liquid crystal layer 7 capable of forming a chiral smectic C phase is filled in the space between the two substrates 3 whose thickness is set by the spacer 4. Here, the alignment film is a vertical alignment film that aligns liquid crystal molecules in a direction perpendicular to the alignment film, and the layer normal direction of the layer structure of the liquid crystal molecules forming the chiral smectic C phase is substantially perpendicular to the substrate surface. It is comprised so that.

A plurality of line electrodes 5 is formed with a resistance film 8 that electrically connects them in series. Although not shown, at least two of the line electrodes 5 of the upper and lower substrates 3 and 3 are at the same potential because the upper and lower electrodes facing each other are electrically connected.
In the power supply connection portion 9, when two power source electrodes 5 and 5 at both ends are connected to the power source 10 and a voltage is applied, the voltage value is attenuated by the resistance film 8 in the adjacent line electrode 5, and the end to which the voltage is applied. A potential gradient is generated between the line electrodes 5 from one line electrode 5 to the other end line electrode 5. Due to this potential gradient, an electric field 11 close to a horizontal electric field is generated inside the liquid crystal layer 7.
By switching the polarity of the applied voltage, a reverse potential gradient can be applied between the line electrodes 5, and the electric field direction close to the horizontal inside the liquid crystal layer 7 can also be switched.

The dielectric layer 6 formed between the group of line electrodes 5 and the liquid crystal layer 7 is arranged to alleviate a vertical electric field component generated in the vicinity of the line electrode 5, and has a uniform electric field distribution inside the liquid crystal layer 7. Can be generated.
Thus, by switching the horizontal electric field direction inside the liquid crystal layer 7, the direction of the liquid crystal director can be changed to switch the optical path of the light that has passed through the liquid crystal layer 7. In FIG. 1A, light incident in a direction perpendicular to the substrate 3 takes an optical path between the first emitted light a and the second emitted light a ′ by switching the electric field direction.
The number of line electrodes 5, the line width, the line interval, the potential difference between the line electrodes 5 and the like are appropriately set based on the desired optical path size, optical path deflection amount, liquid crystal material, and the like.
In FIG. 1B, the line electrode 5 is disposed at an opposing position between the upper and lower substrates 3, but this is not a limitation.

Here, the liquid crystal layer 7 will be described in detail. A “smectic liquid crystal” is a liquid crystal layer in which the long axis directions of liquid crystal molecules are arranged in layers. With respect to such a liquid crystal, 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 is referred to as “ It 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 liquid crystal director direction is spirally rotated for each layer in a state where an external electric field does not work, and is called a “chiral smectic C phase”. In addition, the chiral smectic C reciprocal ferroelectric 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 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, a ferroelectric liquid crystal is taken as an example of the liquid crystal layer 7 and the light deflection element is described. However, the liquid crystal layer 7 can be similarly used in the case of an antiferroelectric liquid crystal. The structure of a ferroelectric liquid crystal composed of a chiral smectic C phase is composed of a main chain, a spacer, a skeleton, a bonding part, a chiral part, and the like. As the main chain structure, polyacrylate, polymethacrylate, polysiloxane, polyoxyethylene and the like can be used.
The spacer 4 is for linking a skeleton, a bonding part, and a chiral part that are responsible for molecular rotation to the main chain, and an appropriate length of methylene chain or the like is selected. In addition, a —COO— bond or the like is selected as a bond portion that bonds the chiral portion and a rigid skeleton such as a biphenyl structure.
The ferroelectric liquid crystal 7 composed of the chiral smectic C phase has a rotational axis of molecular helical rotation perpendicular to the surface of the substrate 3 by the alignment film, and forms so-called homeotropic alignment. As the alignment film, a silane coupling agent or a commercially available vertical alignment material for liquid crystal can be used.

In the present embodiment, the group of line electrodes 5 and the resistance film 8 are formed of the same material. When the surface resistivity of the resistance film 8 is R _R and the surface resistivity of the line electrode 5 is R _E , R _R > R _E
In order to prevent the resistance film 8 from functioning stably, causing no resistance breakdown, and not having an adverse effect due to heat on the liquid crystal layer 7 of the optical deflection element, the resistance value of the resistance film 8 is the direction in which the current flows. Is preferably 1 × 10 ⁸ Ω / cm or more.
If the width 12 of the resistive film 8 is 5 mm, _RR may be 5 × 10 ⁷ Ω / □ or more. As a method for forming the line electrode 5 group and the resistance film 8, a physical deposition method such as sputtering or vapor deposition or a coating method can be used, but a film with less unevenness in thickness and resistance can be formed, or a substrate. Since the degree of freedom of selection of 3 is wide, the physical deposition method is excellent. In order to form the electrode shape, there are a method of masking portions other than the formation portion during film formation, and a method of performing etching and lift-off processing.

If the material for forming the group of line electrodes 5 and the resistance film 8 is a material whose resistivity changes depending on the conditions at the time of film formation and post-treatment after film formation, both are formed of the same material, and R _R > R _E can be used. Thereby, the material cost can be reduced.
It is also possible to form a second layer that becomes a resistance film after the low resistance layer for the line electrode 5 is formed, and then form a line shape by etching.
Compared with the case where the line electrode 5 group is first formed by film formation and etching, and then the resistance film 8 is formed again, it is possible to manufacture an element by a simple process. In particular, the advantage is great when a vacuum process is used for forming the film.
In the present embodiment, the first layer of line electrodes 5 is formed by forming an ITO film while heating the substrate 3, and then the second layer of resistive film while water cooling the substrate 3 using the same ITO. 8 is formed. It is used that the higher the substrate temperature during film formation, the better the crystallinity of the film and the lower the resistivity.

FIG. 2 shows a second embodiment. In addition, the same part as the said embodiment is shown with the same code | symbol, and duplication description on the structure which was already performed and the function is abbreviate | omitted unless there is particular need.
Here, one layer 13 serves as both a line electrode group and a resistance film. A portion surrounded by a broken line 14 corresponds to a resistance film, and the surface resistivity here is higher than the other portions.
For example, after forming the layer 13 in a predetermined shape using ITO, the above condition can be realized by locally heating only the inside of the region 14 in air to increase the resistance. When ITO is heated in air (in the presence of oxygen), oxygen is taken in and resistance increases. Alternatively, it may be possible to reduce the resistance by heating only the outside of the region 14 in vacuum by utilizing the fact that the resistance is lowered when the ITO is heated in vacuum to improve the crystallinity.
Alternatively, the resistance outside the region 14 can be reduced by impurity doping by partial ion beam irradiation.

As described above, by forming the resistance film and the line electrode group with a single layer, there is an advantage that the film forming process can be completed once. In addition, unlike the case of the laminated structure, there is no concern that impurities enter between the two layers or the surface characteristics of the first layer change before the second layer is formed. The electrical contact between the line electrode groups can be made relatively good.
As a material for forming the line electrode group and the resistance film, a light-transmitting oxide material is suitable. Since the line electrode group is formed in a region through which light passes, the higher the transmittance of the material forming the line electrode group, the better. In addition, since the resistivity of the film formed using an oxide material can be changed greatly depending on conditions during film formation or post-treatment after film formation, R _R > R _E can be easily achieved.
If the difference between R _R and R _E is small, the entire potential of one line electrode may not be the same and electric field unevenness may occur. However, if an oxide material is used, the difference in resistivity can be greatly increased, and electric field unevenness can occur. Is suppressed, the electric field generation efficiency is increased, and an efficient optical deflection element can be obtained.

Among oxide materials, the stability of electrical properties is relatively good, and processing such as etching is easy. Therefore, ITO that easily forms the shape of the line electrode group is excellent.
When ITO is used, the resistance can be locally changed by post-processing after film formation as described below. Since ITO is an n-type semiconductor, the number of conduction electrons as carriers can be increased and the resistance can be lowered by injecting H ⁺ ions or the like between vacancies or between lattices.
In addition, metal ions constituting the oxide can be replaced with implanted metal ions, and carriers can be increased. For n-type metal oxides such as ITO, metal ions having a higher valence than the constituent metal ions may be implanted.
Alternatively, oxygen may be substituted with an element such as F, Cl, Br, or I. In order to promote the substitution, heating may be performed after doping.

A third embodiment (example of application to an image display device) will be described with reference to FIG.
In FIG. 3, reference numeral 15 denotes a light source in which LED lamps are arranged in a two-dimensional array. In the traveling direction of light emitted from the light source 15 toward the screen 20, as a diffusion plate 16, a condenser lens 17, and an image display element. A transmissive liquid crystal panel 18 and a projection lens 19 as an optical member for observing the image pattern are sequentially arranged.
Reference numeral 21 denotes a light source drive unit for the light source 15, and 22 denotes a drive unit for the transmissive liquid crystal panel 18.
On the optical path between the transmissive liquid crystal panel 18 and the projection lens 19, light deflecting means 23 functioning as a pixel shift element is interposed and connected to the drive unit 24. As such an optical deflection means 23, an optical deflection element as shown in FIG. 2 is used.

The illumination light that is controlled by the light source drive unit 21 and emitted from the light source 15 becomes uniform illumination light by the diffusion plate 16, and is controlled by the condenser lens 17 in synchronization with the illumination light source by the liquid crystal drive unit 22 to be a transmission type. The liquid crystal panel 18 is critically illuminated.
The illumination light that has been spatially light modulated by the transmissive liquid crystal panel 18 enters the light deflector 23 as image light, and the light deflector 23 shifts the image light by an arbitrary distance in the pixel arrangement direction. This light is magnified by the projection lens 19 and projected onto the screen 20.
By displaying the 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 light deflection unit 23, the apparent appearance of the transmissive liquid crystal panel 18 is displayed. Display by multiplying the number of pixels.
Thus, the shift amount by the light deflection means 23 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 18. By correcting the image signal for driving the transmissive liquid crystal panel 18 by the shift amount according to the shift amount, an apparently high-definition image can be displayed. At this time, since the light deflection element in the above-described embodiment is used as the light deflection means 23, the cost can be suppressed with a simple manufacturing process, and an image display apparatus that operates stably can be obtained.

(Comparative Example 1)
A glass plate having a size of 70 mm × 50 mm and a thickness of 1 mm is used as a substrate, and line electrode groups are formed in parallel to the longitudinal direction. A magnetron sputtering method was used as a film forming method, and sputtering was performed in an atmosphere of oxygen: argon = 5: 95 using ITO as a target. The substrate temperature was kept at 100 degrees.
The film thickness of the ITO line electrode was about 50 nm. The volume resistivity of the ITO film obtained under these conditions is as low as 10 ⁻³ Ωcm or less, and the surface resistivity is about 200 Ω / □. Etching formed 400 line electrodes having a width of 10 μm and a pitch of 100 μm.
Next, in accordance with a conventional method, a Cr—SiO resistance film was formed by magnetron sputtering while masking the part other than the resistance film formation portion. Cr—SiO (10 mol%: 90 mol%) was used as a target, and sputtering was performed in argon gas. The thickness of the resistance film was 100 nm. The volume resistivity of the Cr—SiO film having this composition is about 400 Ωcm, and the surface resistivity is 4 × 10 ⁷ Ω / □.

A cover glass having a thickness of 150 μm was attached to the entire surface with an optical UV adhesive having a thickness of 10 μm in an area of 50 mm × 50 mm excluding the power supply connection portion. Next, after the surface of the cover glass was treated with the vertical alignment agent JALS2021-R2, both substrates were bonded together by mixing a spacer having a particle diameter of 50 μm into the adhesive, and an optical deflecting element similar to FIG. 1 was produced. The spacer member and the adhesive were arranged around the effective area so that the effective area of the element was 40 mm × 40 mm or more.
Next, a ferroelectric liquid crystal (CS1029 manufactured by Chisso) was injected between the two substrates by a capillary method while the substrate was heated to 90 degrees. The four power connection portions of the upper and lower substrates were each connected to a power source by connection lines. An AC voltage of ± 2 kV and 60 Hz was applied to confirm the optical path shift. When the shift amount was measured at each measurement point over the entire effective area, the average value was about 5 μm, and the variation was within 6%.

ITO for line electrodes with a glass plate of size 70 mm x 50 mm and thickness 1 mm as a substrate, masking a rectangular area from one short side (referred to as side A) to 19 mm and a thickness of about 50 nm on the other part A film was formed. The target was ITO, the sputtering gas composition was oxygen: argon = 5: 95, and the substrate temperature was 100 degrees.
The volume resistivity of the ITO film obtained under these conditions is as low as 10 ⁻³ Ωcm or less, and the surface resistivity is about 200 Ω / □. Next, a region other than the rectangular region having a width of 13 mm to 20 mm from the side A was masked, and then the ITO for the resistance film was sputtered. The substrate temperature was 100 ° C., and the sputtering gas composition was oxygen: argon = 80: 20. The thickness is 100 nm.
The ITO film formed under these conditions had a volume resistivity on the order of 10 ³ Ωcm, and the surface resistivity was 10 ⁸ Ω / □. Subsequently, the shape of the line electrode group and the resistance film parallel to the long side similar to FIG. 1 was formed by etching. At this time, the shape of the resistance film was 13 mm to 18 mm from the side A and 5 mm wide. As a result, each line electrode made of low-resistance ITO is electrically connected by the ITO resistance film.

An optical deflecting element similar to that shown in FIG. 1 was produced in the same procedure as in Comparative Example 1 using two substrates on which a line electrode and a resistance film were formed by the above method. With the substrate heated to 90 degrees, a ferroelectric liquid crystal (CS1029 manufactured by Chisso) was injected between the two substrates by a capillary method. The four power connection portions of the upper and lower substrates were each connected to a power source by connection lines.
An AC voltage of ± 2 kV and 60 Hz was applied to confirm the optical path shift. When the shift amount was measured at each measurement point over the entire effective area, the average value was about 5 μm, and the variation was within 6%. It was confirmed that the optical deflection performance of the device in which the line electrode group and the resistance film were formed of the same material and manufactured by a simple process was completely the same.

An ITO film having a low resistance was formed on the entire surface of a glass substrate having a size of 70 mm × 50 mm and a thickness of 1 mm. The film forming method was a magnetron sputtering method, the sputtering gas composition was oxygen: argon = 5: 95, and the substrate temperature was 100 degrees. The thickness of the ITO film is about 100 nm, and the surface resistivity is 100Ω / □. Next, the line electrode group and the portion for forming the resistance film were covered with a resist, and ITO was patterned by wet etching, thereby forming a layer having a similar shape to the layer 13 in FIG. Further, only the ITO film in the region indicated by reference numeral 14 in FIG. 2 was locally heated by a laser.
By performing the heat treatment in air, oxygen is taken into the ITO film and the degree of oxygen deficiency is lowered, so that the number of carriers is reduced and the resistance is increased. By heating at 280 ° C. for 30 minutes, the ITO in the region 14 increased in resistance, and the surface resistivity increased to 10 ⁹ Ω / □. There was no change in the resistivity of the ITO film other than the region 14.
Thus, a line electrode portion having a low resistance and a resistance film portion having a high resistance could be formed using a single layer of ITO film.

An optical deflecting element similar to that shown in FIG. 2 was produced in the same procedure as in Comparative Example 1 using two substrates subjected to the above treatment. With the substrate heated to 90 degrees, a ferroelectric liquid crystal (CS1029 manufactured by Chisso) was injected between the two substrates by a capillary method.
The four power connection portions of the upper and lower substrates were each connected to a power source by connection lines. An AC voltage of ± 2 kV and 60 Hz was applied to confirm the optical path shift. When the shift amount was measured at each measurement point over the entire effective area, the average value was about 5 μm, and the variation was within 6%. It was confirmed that an element manufactured by a simple method of forming the line electrode part and the resistance film part by post-processing by reducing the film forming process at a time shows similar light deflection performance. Moreover, since ITO was used, patterning by etching was easy, and the superiority of ITO was confirmed.
The above element was continuously driven for 10 hours, but there was no change in the shift amount and its variation. Further, when the resistance value of each part of the ITO film was measured after being left for 10 days without being operated, the amount of change was reduced to 5% or less. These depend on the stability of the electrical properties of ITO.

An image display device as shown in FIG. 3 was produced. A 0.9-inch diagonal XGA (1024 × 768 dots) polysilicon TFT liquid crystal panel was used as the image display element. The pixel pitch 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, a so-called field sequential method is employed in which RGB three-color LED light sources are used as the light source, and color display is performed by switching the color of light applied to the one liquid crystal panel at a high speed.
In this embodiment, it is assumed that the frame frequency of image display is 60 Hz, and the subfield frequency for pixel multiplication by 4 times by pixel shift is 240 times, which is 4 times. In order to further divide one subframe into three colors, an image corresponding to each color is switched at 720 Hz. By turning ON / OFF the LED light source of the corresponding color in accordance with the display timing of each color image on the liquid crystal panel, the viewer can see a full color image.

The basic configuration of the optical deflection element is the same as that of Example 2, but the spacer thickness was set to 90 μm and the optical path shift amount was set to about 9 μm. A square wave voltage of ± 2000 V can be applied to the power supply connection portion of the line electrode using a pulse generator and a high-speed power amplifier.
Two of these elements were used, the incident side being the first optical path deflection element and the exit side being the second optical path deflection element. The electrodes are arranged so that the directions of the electrodes are perpendicular to each other and coincide with the arrangement direction of the pixels of the image display element. Further, a polarization plane rotating element is provided between the first and second optical path deflecting elements. As the polarization plane rotation element, first, a polyimide-based alignment material was spin-coated on a thin glass substrate (7 cm × 9 cm, thickness 0.15 mm) to form an alignment film of about 0.1 μm. A rubbing treatment was performed after the annealing treatment of the glass substrate. An empty cell was produced by sandwiching an 8 μm thick spacer between the two glass substrates and pasting the upper and lower substrates so that the rubbing directions were orthogonal.
Into this cell, a nematic liquid crystal having positive dielectric anisotropy and an appropriate amount of a chiral material mixed was injected under normal pressure to produce a TN liquid crystal cell in which the orientation of liquid crystal molecules was twisted by 90 degrees. Since this cell is not provided with an electrode, it functions as a simple polarization rotation element.

The polarizing plate of light emitted from the first light deflecting element and the incident surface of the polarization rotating element are arranged so as to be sandwiched between the two light deflecting means so that the rubbing directions of the incident surface of the polarization rotating element coincide. The polarization plane of the outgoing light from the first light deflection element is rotated by 90 degrees by the polarization plane rotation element, and coincides with the deflection direction of the second light deflection element. An optical path deflecting device comprising a first deflecting element, a polarization plane rotating element, and a second deflecting element was installed immediately after the liquid crystal light valve. Further, in this embodiment, the light emitted from the liquid crystal display element is already linearly polarized light and the polarization direction thereof is arranged so as to coincide with the optical path deflection direction of the first optical path deflection element. In order to ensure the degree of polarization of incident light, a linearly polarizing plate was provided on the incident surface side of the optical path deflecting element.
The frequency of the rectangular wave voltage for driving the optical deflection element was set to 120 Hz, and the drive timing was set so as to shift the pixels in four directions by shifting the vertical and horizontal phases by 90 degrees. By rewriting the subfield image to be displayed on the image display element at 240 Hz, a high-definition image in which the apparent number of pixels in the vertical and horizontal directions was quadrupled could be displayed.
By using the optical deflection element described in Example 2 that can be manufactured in a simple process and operates stably, a high-quality image display apparatus can be obtained at low cost.

It is a figure which shows the optical deflection | deviation element in the 1st Embodiment of this invention, (a) is a front view, (b) is sectional drawing in the broken line 2 of (a). It is sectional drawing of the optical deflection | deviation element in 2nd Embodiment. It is a schematic block diagram of the image display apparatus in 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Substrate 5 Line electrode 7 Liquid crystal layer 8 Resistive film 15 Light source 18 Transmission type liquid crystal panel as an image display element 19 Projection lens as an optical member 22 Drive unit as a display driving means

Claims (6)

Light having a pair of transparent substrates, a plurality of transparent line electrodes provided on at least one substrate, a liquid crystal layer provided between the substrates, and a resistance film electrically connecting the line electrode group In the deflection element,
An optical deflection element, wherein the line electrode and the resistance film are made of the same material, and their respective functions are separated by making the surface resistivity of the both different. A pair of transparent substrates, a plurality of transparent line electrodes arranged substantially parallel to the desired optical path shift direction in a region including the optical path on the substrate, and a chiral smectic C phase within the distance between both substrates Having a liquid crystal layer and a resistance film electrically connecting the line electrode group in series,
An optical deflection element in which R _R > R _E when the resistance film and the line electrode are made of the same material, and R _R is the surface resistivity of the resistance film and R _E is the surface resistivity of the line electrode. The optical deflection element according to claim 1 or 2,
The optical deflection element, wherein the resistance film and the line electrode group are a single film formed simultaneously. In the light deflection element according to claim 1, 2, or 3,
The optical deflection element, wherein the resistance film and the line electrode group are made of an oxide material. The light deflection element according to claim 4,
The optical deflection element, wherein the oxide material is tin-containing indium oxide. 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 for illuminating the image display element, and an image pattern displayed on the image display element An optical member, display driving means formed by a plurality of subfields obtained by dividing an image field in time, and an optical deflection element for deflecting the optical path of light emitted from each pixel, and deflecting the optical path for each subfield In the image display device that displays the image pattern in a state where the display position is shifted according to the image display device by multiplying the apparent number of pixels of the image display element,
An image display device, wherein the light deflection element is the light deflection element according to claim 1, 2, 3, 4 or 5.

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