JP4917757B2 - Optical deflection element and image display device - Google Patents

Description

  The present invention relates to an optical deflection element and an image display device, and more particularly, to an optical deflection element and an image display device that change an optical path by changing a liquid crystal director direction to a desired direction.

  Conventionally, as an optical deflecting device that deflects and emits incident light using an optical deflecting element, KH2PO4_KDP_, NH4H2PO4_ADP_, LiNbO3, LiTaO3, GaAs, CdTe and other primary electrooptic effects, materials having a large Pockels effect, KTN, There are known electro-optic devices using materials having a large secondary electro-optic effect such as SrTiO 3, CS 2, nitrobenzene, and acousto-optic devices using materials such as glass, silica, TeO 2 (for example, edited by Shoji Aoki; “Optoelectronic Devices”, Shosodo). Various optical deflecting devices using an optical deflecting element including a liquid crystal material have been proposed.

  For example, a light deflecting device and a light beam shifter that are designed to reduce the optical loss disclosed in Patent Literature 1 and Patent Literature 2, and light produced by the optical deflection element disclosed in Patent Literature 3, Patent Literature 4, and Patent Literature 5. There are optical deflecting devices and the like that reduce the power and size of the deflection operation.

  Further, for example, an optical deflection device in which a deflection angle is expanded by an optical deflection element disclosed in Patent Document 6, Patent Document 7, and Patent Document 8, disclosed in Patent Document 9, Patent Document 10, and Patent Document 11. There is an optical deflecting device in which a deflection angle can be adjusted by an optical deflecting element.

  In such an optical deflection apparatus, as disclosed in Patent Documents 12 and 13, the deflection angle of the optical path by the optical deflection element can be adjusted without using a mechanical movable unit that complicates the configuration.

  Patent Document 14 discloses an image display device in which a display image on an image display element is divided and displayed in a plurality of fields, an image is displayed for each field, and an optical path is shifted for each corresponding field.

In Patent Document 15, a technology that realizes miniaturization, high accuracy, and high resolution by sandwiching a translucent piezoelectric element between transparent electrodes and changing the thickness by applying a voltage to shift the optical path. Has been proposed.
Japanese Patent Laid-Open No. 6-18940 JP-A-5-313116 JP 2000-193925 A JP-A-9-133931 JP-A-5-204001 JP-A-6-194695 JP-A-6-258646 JP-A-6-222368 JP-A-9-133904 Special Table 2000-507005 JP-A-11-109304 JP 7-64123 A JP-A-8-262391 JP-A-6-324320 JP-A-10-133135

  However, the above invention has the following problems.

  When the optical deflecting element is a material having a large primary electro-optic effect or Pockels effect, an electro-optic device using a material having a large secondary electro-optic effect, an acousto-optic device, or the like, a sufficiently large light deflection In order to obtain the quantity, it is generally necessary to increase the optical path length. For this reason, it is difficult to reduce the size, and the use is limited because the material is expensive.

  In addition, the above-described optical deflection apparatus includes a projection optical system in an image display apparatus that displays an image displayed on the image display element on a screen or the like by a projection optical system, an optical switch that uses an optical path shift of outgoing light with respect to incident light, and the like. Used for. In an image display device using such an optical deflector, an image displayed on the image display element is shifted at a high speed according to time by the optical deflector to cause an afterimage phenomenon in human vision. There are some which display an image with improved resolution on the screen. The timing and shift timing of the light deflection operation by the light deflection device used in such an image display device must be high enough to cause an afterimage phenomenon in human vision and no blurring occurs in each image.

  However, for example, in the technique described in Patent Document 1, since nematic liquid crystal is used as the liquid crystal material, it is difficult to increase the response speed to sub-milliseconds. In the technique described in Patent Document 9, a smectic A-phase ferroelectric liquid crystal is used as the liquid crystal material. However, since the smectic A-phase liquid crystal material does not have spontaneous polarization, the response speed should be sufficiently increased. Is difficult. As described above, the optical deflecting device having a simplified configuration and a small size has a problem that it is difficult to increase the speed of the optical path shifting operation due to the characteristics of the liquid crystal material used.

  In the technique described in Patent Document 2, when the optical path shift operation is performed by moving each member arranged on the optical path, each member arranged on the optical path must be translated at high speed and accurately. Therefore, accuracy and durability of the movable part are required, and light loss can be reduced, but generation of vibration and noise and an increase in size of the apparatus are problems.

  Further, the means for shifting the optical path described in Patent Document 14 complicates the configuration for driving the optical deflection element and increases the cost. Furthermore, the technique described in Patent Document 15 requires a relatively large transparent piezoelectric element, which increases the cost of the apparatus.

  Further, when a horizontal electric field of about 100 V / mm is applied in the liquid crystal layer of the light deflection element, it is necessary to apply a large potential difference proportional to the effective width of the element. For example, it is necessary to apply a voltage of 4000 V to an element having an effective width of 40 mm. Therefore, the end of the transparent electrode line group provided on the substrate surface and a part of the electrode connection portion at the time of driving the optical deflection element hold the two optical deflection elements combined as shown in FIG. 10 or hold the optical deflection element. The discharge is caused in a narrow space with the holder to be cut, and the details of the transparent electrode line are disconnected.

  Therefore, the present invention aligns liquid crystal molecules between a pair of substrates substantially vertically, generates an electric field in a direction substantially parallel to the liquid crystal layer, and changes the liquid crystal director direction to a desired direction to switch the optical path. In the optical deflection element and the optical deflection method, the end of the transparent electrode line group and a part of the electrode connecting portion are covered with a covering member, so that the optical deflection element and the optical deflection method can be used in a narrow space between the optical deflection elements or the holder holding the optical deflection element. It is an object of the present invention to propose an optical deflection element and an image display device that prevent the transparent electrode line from being damaged by the discharge.

The invention described in claim 1 includes a pair of transparent substrates, a plurality of transparent electrode line groups arranged on the substrates, and a chiral smectic C phase substantially perpendicular to the substrate surface between the substrates in a side view. A plurality of transparent electrodes, and a liquid crystal layer provided with spacers separated from each other in a side view from a resistor formed by coating with ATO (antimony-containing tin oxide) and having a thickness of about 10 μm is disposed between the line groups, the a side and the dielectric layer formed on the resistive body in view, and the resistor which electrically connects the transparent electrode line groups, between the transparent electrode lines In the optical deflection element that deflects the optical path by generating a potential gradient, the dielectric layer covers the transparent electrode line group and the resistor.

  The present invention is a light beam that switches liquid paths by aligning liquid crystal molecules substantially vertically between a pair of substrates, generating an electric field in a direction substantially parallel to the liquid crystal layer, and changing the liquid crystal director direction to a desired direction. In the deflecting element and the light deflecting method, discharge in a narrow space between the light deflecting elements or with the holder holding the light deflecting element by covering the end of the transparent electrode line group and a part of the electrode connecting part with a covering member. Prevents damage to the transparent electrode line.

  Hereinafter, the configuration of an optical deflection element according to an embodiment of the present invention will be described.

  FIG. 1A is a sectional view of an optical deflection element in which a resistor 24 is arranged outside the optical deflection element, and FIG. 1B is a plan view. In this optical deflection element, a pair of transparent substrates (2A, 2B) are arranged to face each other with a spacer 6 interposed therebetween. A plurality of transparent electrode line groups 3A are formed on the inner surface of the substrate. A dielectric layer 4 is disposed on the inner surface of the transparent electrode line group 3 </ b> A, and an alignment film (not shown) is formed on the inner surface of the dielectric layer 4. A liquid crystal layer 8 capable of forming a chiral smectic C phase is filled in the distance between the two substrates whose thickness is set by the spacer 6. 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.

  The plurality of transparent electrode line groups 3 </ b> A are connected to an arrayed resistor 24 provided outside the element by the FPC 25. When an electric field is applied to the optical deflection element by the power source 9, an electric field is applied in a stepwise manner between the transparent electrode lines adjacent to the arrayed resistor 24 outside the element, and an electric field 10 close to a horizontal electric field is applied to the inside 8 of the liquid crystal layer. Will occur. By switching the polarity of the applied voltage, a potential gradient in the opposite direction can be given between the transparent electrode lines, and the electric field direction close to the horizontal inside the liquid crystal layer can be switched. The dielectric layer 4 formed between the transparent electrode line group 3A and the liquid crystal layer 8 is arranged to alleviate a vertical electric field component generated in the vicinity of the transparent electrode line, and has a uniform electric field distribution inside the liquid crystal layer. Can be generated. Thus, by switching the horizontal electric field direction inside the liquid crystal layer 8, 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.

  In FIG. 1A, light incident in a direction perpendicular to the substrate takes an optical path between the first outgoing light b and the second outgoing light b ′ by switching the electric field direction. The number of electrode lines, the line width, the line interval, the potential difference between the electrode lines, and the like are appropriately set based on a desired optical path size, optical path deflection amount, liquid crystal material, and the like. Further, in FIG. 1A, the transparent electrode lines are arranged at opposing positions between the upper and lower substrates, but this is not restrictive.

  Here, the liquid crystal layer 8 will be described in detail. A “smectic liquid crystal” is a liquid crystal layer in which major axis directions of liquid crystal molecules are arranged in layers. With regard 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 the 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 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, a ferroelectric liquid crystal is used as an example of the liquid crystal layer 8 to explain the light deflection element. However, the liquid crystal layer 8 can be similarly used for an antiferroelectric liquid crystal. The structure of a ferroelectric liquid crystal composed of a chiral smectic C phase includes 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 is for linking a skeleton, a bonding part, and a chiral part responsible for molecular rotation to the main chain, and a methylene chain having an appropriate length 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 8 composed of the chiral smectic C phase has a so-called homeotropic alignment because the alignment film is oriented so that the rotation axis of the molecular helical rotation is perpendicular to the substrate (2A, 2B) surface. As the alignment film, a silane coupling agent or a commercially available vertical alignment material for liquid crystal can be used.

  In the optical deflection element having such a configuration, the covering member is formed on the transparent electrode line group in which the dielectric layer is not formed. When a light deflection element having a configuration in which the covering member is not formed on the transparent electrode line group 3A is operated, a narrow space with a holder for holding the light deflection element or a substrate when a plurality of light deflection elements are combined as shown in FIG. Discharge occurs in the narrow space between them, and disconnection occurs in the transparent electrode line. However, discharge can be prevented by forming the covering member 22 on the transparent electrode line group 3A exposed to the air of the light deflection element. The covering member may be a material having a resistivity equal to or higher than that of the transparent electrode line group 3A, but the covering member 22 made of an insulating material is preferable. Examples of the covering member that can be easily used include an insulating adhesive tape such as Kapton tape and a self-adhesive silicone rubber.

  FIG. 2 shows a configuration of an optical deflection element in which a resistor that electrically connects transparent electrode line groups in series is formed. (B) is a plan view, (a) is a side view as viewed from the lower side of (b), (c) is a cross-sectional view as viewed from the left side of (b), and (d) is the vicinity of the electrode connection portion of the substrate. It is a plane enlarged view. In this optical deflection element, a pair of transparent substrates (2A, 2B) are arranged to face each other with a spacer 6 interposed therebetween. A plurality of transparent electrode line groups 3A and electrode connection portions 3B are formed on the inner surface of the substrate. A dielectric layer 4 is disposed on the inner surface of the transparent electrode line group 3 </ b> A, and an alignment film (not shown) is formed on the inner surface of the dielectric layer 4. A liquid crystal layer 8 capable of forming a chiral smectic C phase is filled in the distance between the two substrates whose thickness is set by the spacer 6. 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. Resistors 7 that are electrically connected in series are formed in the plurality of transparent electrode line groups 3A. Furthermore, the transparent electrode which becomes the electrode connection part 3B is drawn out from at least both ends of the transparent electrode line group 3A. In FIG. 2D, the resistor 7 side is the transparent electrode line group 3A with the broken line 12 as a boundary, and the portions drawn from the transparent electrode line group 3A at both ends are the electrode connection portions 3B. The electrode connecting portion 3B needs at least two portions at both end portions, but a plurality of electrode connecting portions may be further provided.

  In such an optical deflection element, when a voltage is applied between the transparent electrode lines provided at both ends of one substrate by the power source 9, the voltage value is attenuated by the resistor 7 in the adjacent transparent electrode lines, and the voltage A potential gradient is generated between each transparent electrode line from the end line to which the voltage is applied to the opposite end line. Due to this potential gradient, an electric field 10 close to a horizontal electric field is generated in the liquid crystal layer 8, and the optical path of light can be switched in the same manner as the optical deflection element shown in FIG. 1 by changing the polarity of the applied voltage. .

The resistor 7 that generates a potential gradient between the transparent electrode lines may be any resistor that expresses a desired resistance value and can be formed on the transparent electrode line. In order to ensure that the resistor functions stably, there is no resistance breakdown, and there is no adverse effect of heat on the liquid crystal layer of the light deflection element, a material with a surface resistance of 1 × 10 ⁷ Ω / m ² or more is required. preferable. Specifically, chromium oxide, tin oxide, antimony oxide, zinc oxide, ATO (antimony-containing tin oxide), or a material in which these fine particles are dispersed in a resin can be used. As a forming method on the transparent electrode line, a deposition method or a sputtering method, or a coating type resistor material, a spin coating method, a flexographic printing method, a screen printing method, or a jetting method such as a nozzle or an ink jet method may be used. Can be used. Depending on the formation method, it is also necessary to mask other than the portion where the resistor is formed. The resistor 7 needs to electrically connect all of the plurality of transparent electrode line groups 3A arranged on the substrate in series, from one end of the transparent electrode line to the other end of the transparent electrode line. It is important to form them continuously in between. The formation width of the resistor on each transparent electrode line group is slightly different depending on the resistor material, but is preferably a width that does not cause peeling or disconnection in the external impact to the light deflection element or the connection process to the power source. . However, when the formation width is wide, the function of the optical deflection element does not deteriorate, but there is a drawback that the outer size of the optical deflection element becomes large. Therefore, the width of the resistor on each transparent electrode line is preferably about 1 mm to 5 mm.

  In the optical deflection element having such a configuration, the electrode connection portion 3B connected to the transparent electrode line group 3A in which no dielectric layer is formed and the power source 9 is made of a material having a high resistivity higher than that of the resistor 7, or preferably A covering member 22 made of an insulating material is formed. When a light deflection element having a configuration in which a covering member is not formed on the transparent electrode line group 3A and the electrode connection portion 3B is operated, a narrow space between the holder for holding the light deflection element and the light deflection element shown in FIG. As described above, discharge occurs in a narrow space between the substrates when a plurality of light deflection elements are combined, and disconnection occurs in the transparent electrode line. However, discharge can be prevented by forming the covering member 22 on the transparent electrode line group 3A and the electrode connecting portion 3B exposed to the air of the light deflection element. As the covering member 22, it is difficult to apply a uniform potential gradient to the transparent electrode line by energizing the low-resistance covering member when an electric field is applied to a covering member having a resistivity of 7 or less. Therefore, it is necessary to be a member having a resistivity of at least the resistor 7. Note that these portions need not be transparent because they are outside the optical path region.

  FIG. 3 is an enlarged view of the vicinity of the electrode connecting portion 3B of the substrate of the optical deflection element using the resistor 7 as the covering member 22 of the transparent electrode line group. In a conventional optical deflecting element, disconnection occurs in the transparent electrode line due to the occurrence of discharge in a narrow space, and when the disconnection portion of the element that has stopped operating is observed with a microscope, the transparent electrode line near the electrode connecting portion 3B is deteriorated. Many were seen. However, no deterioration or disconnection was observed in the lower transparent electrode line on which the resistor 7 was formed even in the vicinity of the electrode connection portion 3B.

  Therefore, the covering member is formed by forming the resistor 7 on the transparent electrode line group 3A on which the dielectric layer is not formed as shown in FIG. 3 so that the transparent electrode line group 3A exposed to the air is not formed. Similarly to the case where the transparent electrode line group 3A is covered with the wire 22, the disconnection deterioration of the transparent electrode line group due to discharge during operation can be prevented.

  An optical deflection element according to another embodiment of the present invention will be described.

  FIG. 4 is a side view of the light deflection element viewed from the left in FIG. In this optical deflection element, a pair of transparent substrates (2A, 2B) are arranged to face each other with a spacer 6 therebetween. A plurality of transparent electrode line groups 3A and electrode connection portions 3B drawn from at least two ends of the transparent electrode line group 3A are formed on the inner surface of the substrate. The transparent electrode line group 3A is formed with a resistor 7 that is electrically connected in series. On the inner surface of the transparent electrode line group 3A, a dielectric layer 4 is formed at a position covering the transparent electrode line group 3A and the resistor 7 except for the electrode connection portion 3B. Further, an alignment film (not shown) is formed on the inner surface of the dielectric layer 4. A liquid crystal layer 8 capable of forming a chiral smectic C phase is filled in the distance between the two substrates whose thickness is set by the spacer 6. 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. The operation of the optical deflection element can be performed by applying an electric field to the electrode connection portion 3B where the dielectric layer 4 is not formed. By forming the dielectric layer 4 at a position covering the transparent electrode line group 3A and the resistor 7, the covering member 22 of the transparent electrode line group 3A can be obtained. In the optical deflection element having such a configuration, the dielectric layer 4 also serves as a covering member for the resistor 7 and improves the resistance of the resistor against changes in the external environment such as temperature and humidity. 7 can be prevented from peeling. The dielectric layer 4 is formed by the adhesive 5, but the resistor 7 is formed from a thin film of about 800 to 1000 mm by sputtering of CrSiO, for example, and the thickness of the adhesive layer forming the dielectric layer 4 is Since the thickness is sufficiently smaller than the thickness, there is no problem such as distortion on the dielectric surface due to the thickness of the resistor film. Further, even when a dielectric layer 4 is formed on a coating type resistor such as ATO (antimony-containing tin oxide) to a thickness of about 10 μm and there is a concern about distortion, the spacer 6 is more liquid crystal than the resistor 7. By providing it on the layer 8 side, it is possible to avoid the variation in the thickness of the liquid crystal layer 8 due to the distortion of the substrate.

  The connection between the electrode connection portion 3B on which the dielectric layer 4 is not formed and the power source 9 can be connected by solder, conductive tape, dootite, etc., but the transparent electrode line is prevented from deteriorating due to the heat of the solder and is connected securely. For this purpose, it is preferable to use ultrasonic solder. In addition, the transparent electrode line group 3A and the electrode connecting portion 3B other than the optical path can be made of a metal material instead of the transparent electrode. However, the electrode connection part 3B connected to the power source 9 by such a method often has a part exposed to the air, and a conductive material such as solder is also exposed to the air. Therefore, when the light deflection element is operated, a narrow space between the electrode connecting portion 3B or a conductive member such as solder and a holder for holding the light deflection element, between the substrates when a plurality of light deflection elements are combined as shown in FIG. There is a possibility that electric discharge occurs in a narrow space. Therefore, in order to prevent danger and prevent deterioration of the optical deflection element due to continuous operation, the electrode connecting portion 3B and the conducting member must be covered with a covering member 22 having a resistivity equal to or higher than that of the resistor 7.

  Further, as a method of covering the electrode connecting portion 3B more securely and connecting without fear of disconnection or deformation, there is a method of assembling the detachable power supply means 11 shown in FIG. The detachable power supply means 11 may have a shape similar to a connector used for electrical connection, for example. When assembled to the optical deflection element, a shape in which a conducting member is disposed at a portion where the power feeding means 11 and the electrode connecting portion 3B are in contact, and the other portion is formed of an insulating member to cover the transparent electrode of the optical deflection element is preferable. . In order to securely connect without requiring accuracy, contact failure with the electrode connecting portion 3B can be avoided by processing the conducting member of the power feeding means 11 into a spring shape or a plurality of terminal shapes. Further, from the viewpoint of preventing discharge, the power feeding means 11 must be configured to be mounted without leaving a space with the transparent electrode surface of the electrode connecting portion 3B. Further, the power supply means 11 may have any other shape as long as it serves as a connection member for the power source 9 of the optical deflection element and a covering member for the electrode connection portion 3A.

  Next, an optical deflection element according to another embodiment of the present invention will be described.

  FIG. 6A is a cross-sectional view of an optical deflection element in which a resistor 24 is disposed outside the optical deflection element, and FIG. 6B is a plan view. In this optical deflection element, a pair of transparent substrates (2A, 2B) are arranged to face each other with a spacer 6 therebetween. A plurality of transparent electrode line groups 3A are formed on the inner surface of the substrate. A dielectric layer 4 is bonded to the formation surface of the transparent electrode line group 3 </ b> A with a transparent adhesive, and an alignment film (not shown) is formed on the inner surface of the dielectric layer 4. A liquid crystal layer 8 capable of forming a chiral smectic C phase is filled in the distance between the two substrates whose thickness is set by the spacer 6. 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. The plurality of transparent electrode line groups 3 </ b> A are connected to an arrayed resistor 24 provided outside the element by a flexible printed circuit board (FPC) 25. When an electric field is applied to the optical deflection element by the power source 9, a stepwise electric field is applied between adjacent transparent electrode lines by the arrayed resistor 24 outside the element, and an electric field 10 close to a horizontal electric field is applied to the inside 8 of the liquid crystal layer. Will occur. By switching the polarity of the applied voltage, a potential gradient in the opposite direction can be given between the transparent electrode lines, and the electric field direction close to the horizontal inside the liquid crystal layer can be switched. The dielectric layer 4 formed between the transparent electrode line group 3A and the liquid crystal layer 8 is arranged to alleviate a vertical electric field component generated in the vicinity of the transparent electrode line, and has a uniform electric field distribution inside the liquid crystal layer. Can be generated. Thus, by switching the horizontal electric field direction in the liquid crystal layer 8, 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.

  In the optical deflection element having such a configuration, it is necessary to form the covering member 30 on the transparent electrode line group 3A where the dielectric layer 4 is not formed. When a light deflection element having a configuration in which the covering member 22 is not formed on the transparent electrode line group 3A is operated, a narrow space with a holder for holding the light deflection element, when a plurality of light deflection elements are combined as shown in FIG. Discharge occurs in a narrow space between the substrates, and disconnection occurs in the transparent electrode line. However, discharge can be prevented by forming the covering member 30 on the transparent electrode line group 3A exposed to the air of the light deflection element. Here, an adhesive layer for adhering the dielectric layer to the substrate surface is used as the covering member 30. In this configuration, the FPC is attached to the substrate with line electrodes before the dielectric layer 4 is bonded, and a transparent adhesive is applied so as to cover the connection portion of the FPC. Thereafter, the dielectric layer 4 on which an alignment film is previously formed is bonded, and the transparent adhesive is cured. At this time, in order to prevent the planarity of the surface of the dielectric layer from being deteriorated, the dielectric layer 4 is attached at a position avoiding the connecting portion of the FPC. In other words, the adhesive layer protrudes from the dielectric layer 4 to the FPC. The connection portion is covered. As the transparent adhesive, a thermosetting type, an ultraviolet curable type, or the like can be used. As a method for applying the transparent adhesive, a relatively uniform adhesive layer is formed in a desired range by using a printing technique, an inkjet technique, or the like. Alternatively, a large amount of adhesive may be dropped on the center of the substrate, and the dielectric layer 4 may be attached and pressed to allow the adhesive to protrude to the FPC connection portion. The cured transparent adhesive covers the transparent electrode line group to prevent discharge, and at the same time contributes to an increase in the fixing strength of the FPC.

  FIG. 7 shows a configuration of an optical deflecting element in which a resistor 7 for electrically connecting the transparent electrode line group 3A in series is formed. (B) is a plan view, (a) is a side view as viewed from the lower side of (b), (c) is a cross-sectional view as viewed from the left side of (b), and (d) is an electrode connection portion of one substrate. It is a plane enlarged view of the vicinity. In this optical deflection element, a pair of transparent substrates (2A, 2B) are arranged to face each other with a spacer 6 therebetween. A plurality of transparent electrode line groups 3A and electrode connection portions 3B are formed on the inner surface of the substrate. A dielectric layer 4 is attached to the inner surface of the transparent electrode line group 3 </ b> A by a transparent adhesive 5, and an alignment film (not shown) is formed on the inner surface of the dielectric layer 4. A liquid crystal layer 8 capable of forming a chiral smectic C phase is filled in the distance between the two substrates whose thickness is set by the spacer 6.

  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. Resistors 7 that are electrically connected in series are formed in the plurality of transparent electrode line groups 3A. Furthermore, the transparent electrode which becomes the electrode connection part 3B is drawn out from at least both ends of the transparent electrode line group 3A. In FIG. 7D, the resistor 7 side is the transparent electrode line group 3A with the broken line 12 as a boundary, and portions drawn from the transparent electrode lines at both ends are the electrode connection portions 3B. The electrode connection portion 3B needs at least two portions at both ends, but a plurality of connection portions may be provided. When a voltage is applied between the transparent electrode lines at both ends of one substrate by the power source 9 to the optical deflection element having such a configuration, the voltage value is attenuated by the resistor 7 in the adjacent transparent electrode lines, and the voltage is reduced. A potential gradient is generated between the transparent electrode lines from the applied end line to the opposite end line. Due to this potential gradient, an electric field 10 close to a horizontal electric field is generated in the liquid crystal layer 8, and the optical path of light can be switched in the same manner as the optical deflection element of FIG. 1 by changing the polarity of the applied voltage.

  In the optical deflection element described above, the transparent electrode line group 3A in which the dielectric layer 4 is not formed and the electrode connecting portion 3B connected to the power source 9 are made of a material having a higher resistivity than the resistor 7 or an insulating material. The covering member 30 is preferably covered. Here, an adhesive layer for adhering the dielectric layer 4 to the substrate surface is used as the covering member 30.

  In the present embodiment, the transparent adhesive is applied to a region outside the broken line 12 on the substrate surface on which the resistor 7 is formed, and after the dielectric layer 4 is bonded, the transparent adhesive is cured. That is, the adhesive layer protrudes from the dielectric layer and covers the transparent electrode line group and the resistor 7. As the transparent adhesive, a thermosetting type or an ultraviolet curable type is used. As a method for applying the transparent adhesive, a relatively uniform adhesive layer is formed in a desired range by using a printing technique, an inkjet technique, or the like. Alternatively, a large amount of adhesive may be dropped on the center of the substrate, and the dielectric layer 4 may be bonded and pressed to cause the adhesive to protrude beyond the broken line 12. The cured transparent adhesive can cover the transparent electrode line group 3A to prevent discharge and at the same time prevent resistance change due to moisture absorption by the resistor.

Since the transparent adhesive for bonding the dielectric layer 4 is used as the covering member 30, the device manufacturing process can be simplified as compared with the case of newly forming another covering member 30. Further, the area of the dielectric layer 4 can be reduced as compared with the case where the entire transparent electrode line and the resistor 7 are covered with the dielectric layer 4. As the dielectric layer 4, a thin glass of about several hundred microns is used. In order to improve the optical characteristics such as wavefront aberration of the light deflection element, it is necessary to improve the flatness and thickness uniformity of the thin glass. The cost increases due to the addition of a polishing process. Therefore, it is preferable to reduce the formation area of the dielectric layer 4. Therefore, according to this configuration, since the area of the dielectric layer 4 can be kept small, the manufacturing cost of the element can be reduced. (Corresponding to claim 8)
Next, an example in which the light deflection element according to the above-described embodiment is applied to an image display device will be described.

  As shown in FIG. 8, the image display device according to the present embodiment includes a light source 12 in which LED lamps are arranged in a two-dimensional array, and a diffusion arranged in the traveling direction of light emitted from the light source 12 toward the screen 13. A plate 14, a condenser lens 15, a transmissive liquid crystal panel 16 as an image display element, and a projection lens 17 as an optical member for observing the image pattern are arranged in this order. The image display apparatus according to the present embodiment includes a light source drive unit 18 for the light source 12 and a drive unit 19 for the transmissive liquid crystal panel 16.

  Further, on the optical path between the transmissive liquid crystal panel 16 and the projection lens 17, an optical deflection element 20 that functions as a pixel shift element is interposed, and a drive unit 21 is connected. As such an optical deflection element 20, the above-described optical deflection element is used.

  The illumination light that is controlled by the light source drive unit 18 and emitted from the light source 12 becomes uniform illumination light by the diffusion plate 14, and is controlled by the condenser lens 15 in synchronization with the illumination light source by the liquid crystal drive unit 18 to be a transmission type. The liquid crystal panel 16 is critically illuminated. The illumination light spatially modulated by the transmissive liquid crystal panel 16 enters the light deflection element 20 as image light, and the image light is shifted by an arbitrary distance in the pixel arrangement direction by the light deflection element 20. This light is magnified by the projection lens 17 and projected onto the screen 13.

  Here, by displaying 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 in which the image field is time-divided by the light deflection element 20, the appearance of the transmissive liquid crystal panel 16 is apparent. The number of pixels is multiplied and displayed. Thus, the shift amount by the light deflecting means 20 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 16. By correcting the image signal for driving the transmissive liquid crystal panel 16 according to the shift amount by the shift amount, an apparently high-definition image can be displayed. At this time, by using the light deflection element according to each of the above-described embodiments as the light deflection element 20, the light utilization efficiency is improved, and a brighter and higher quality image is provided to the observer without increasing the load on the light source. it can. By performing the optical deflection position control based on the electric field application direction and electric field intensity to the transparent electrode line group 3 and the resistor 7 in the optical deflection element 20, an appropriate pixel shift amount is maintained and a good image can be obtained.

  Next, specific examples of the optical deflection element according to the present embodiment will be described.

(Comparative example)
As shown in FIG. 9, a substrate (2A, 2B) on which 400 ITO line electrodes 3A having a width of 10 μm were formed at a pitch of 100 μm parallel to the longitudinal direction of a glass plate having a size of 60 mm × 50 mm and a thickness of 1 mm was prepared. The ITO line electrode 3A at both ends was widened at one end to form an electrode connection portion 3B. A cover glass having a thickness of 150 μm was attached to the entire surface with an optical UV adhesive in a 50 mm × 50 mm area excluding the width of 10 mm between the resistor forming portion and the electrode connecting portion 3B. Next, after the surface of the cover glass was treated with the vertical alignment agent JALS2021-R2, both substrates were bonded with an adhesive mixed with a spacer having a particle diameter of 50 μm so that the ITO line electrode 3A was parallel and the effective area portion overlapped. . Next, a ferroelectric liquid crystal (CS1029 manufactured by Chisso) is injected between the two substrates with the substrate heated to 90 degrees by the capillary method, and then a resistance is applied on the ITO line electrode group 3A to which the cover glass is not attached. Antimony-containing tin oxide (R308 manufactured by Osaka Cement Co., Ltd.) was printed as a body with a width of about 3 mm. No resistor is formed in the 2 mm width of the ITO line electrode group 3A. Next, a cable was connected to the electrode connecting portion 3B of both substrates with ultrasonic soldering and connected to a power source. When an AC voltage of ± 2 kv 60 Hz was applied, an optical path shift was confirmed over the entire effective area, but a discharge occurred between the two optical deflectors combined as shown in FIG. 10, and the optical path shift could not be confirmed immediately. The ITO line in the vicinity of the electrode connection portion 3B was broken.

  Therefore, in this embodiment, the silicon rubber TSE3663 (made by Toshiba Silicone) is used to connect the ITO line electrode group 3A having a width of 2 mm, which is not formed with a resistor before being connected to the power source, and the electrode connection portion 3B connected by ultrasonic soldering. I covered everything. As shown in FIG. 10, when an AC voltage of ± 2 kv 60 Hz was applied to the optical deflecting element in which two elements were combined, a continuous optical path shift could be confirmed over the entire effective area without discharge.

  Further, on the same substrate as that of the comparative example, CrSiO was formed by sputtering to a thickness of about 1000 mm on the ITO line electrode portion 3A having a width of 5 mm without attaching a cover glass. A light deflecting element was produced in the same manner as in the comparative example except that the antimony-containing tin oxide was not printed. Next, a cable was connected to the electrode connection portion 3B of both substrates with ultrasonic soldering, and only the electrode connection portion 3B and the solder portion were covered with Kapton tape (manufactured by 3M). When an AC voltage of ± 2 kv 60 Hz was applied, a continuous optical path shift could be confirmed over the entire effective area.

  Further, on the same substrate as that of the comparative example, CrSiO was formed on the resistor forming portion to a thickness of about 1000 mm by sputtering. Next, a cover glass having a thickness of 150 μm was attached to the entire surface of the electrode connection portion 3B leaving a width of 5 mm with an optical UV adhesive, and the surface of the cover glass was treated with the vertical alignment agent JALS2021-R2. Next, both substrates were bonded with an adhesive mixed with a spacer having a particle diameter of 50 μm so that the ITO line electrodes 3A were parallel and the 50 mm width of the effective area overlapped. Further, 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 cable was connected to the electrode connecting portion 3B with ultrasonic soldering, and only the electrode connecting portion 3B and the solder portion were covered with Kapton tape (manufactured by 3M). As shown in FIG. 10, when an AC voltage of ± 2 kv 60 Hz was applied to the optical deflecting element in which two elements were combined, a continuous optical path shift could be confirmed over the entire effective area.

  Further, a metal clip with a spring was processed with silicon rubber, and when it was connected to the electrode connecting portion 3B of the light deflection element, it was connected to the power source, and the electrode connecting portion 3B covered the electrode. Until the electrode connection solder pre-process, an optical deflection element similar to that of the above-described embodiment was manufactured and connected to the electrode connection portion 3B with a processed clip. As shown in FIG. 10, when an AC voltage of ± 2 kv 60 Hz was applied to the optical deflecting element in which two elements were combined, a continuous optical path shift could be confirmed over the entire effective area.

  In the image display apparatus having the light polarizing element according to these examples, a high-definition projected image was obtained. In addition, no discharge occurred in a narrow space in the apparatus.

  Next, specific examples of the light polarizing element according to the other embodiment described above will be described. As shown in FIG. 9, a substrate (2A, 2B) on which 400 ITO line electrodes 3A having a width of 10 μm were formed at a pitch of 100 μm parallel to the longitudinal direction of a glass plate having a size of 60 mm × 50 mm and a thickness of 1 mm was prepared. The ITO line electrode portion 3A at both ends is widened at one end to form an electrode connection portion 3B.

  CrSiO was formed to a thickness of about 1000 mm on the resistor forming portion by sputtering. Next, an optical UV adhesive was uniformly applied with a thickness of several microns on the substrate surface by screen printing, leaving a part of the electrode connection portion 3B, and a cover glass having a thickness of 150 μm was bonded thereon. The size of the cover glass was 45 mm × 45 mm slightly larger than the effective area. Thereafter, the adhesive was cured by UV irradiation, the cover glass was bonded, and the ITO line electrode 3A and the resistor 7 were coated. The surface of this substrate (2A, 2B) was treated with the vertical alignment agent JALS2021-R2. Next, both substrates (2A, 2B) were bonded with an adhesive mixed with a spacer having a particle diameter of 50 μm so that the ITO line electrode 3A was parallel and the 50 mm width of the effective area overlapped. Next, in a state where the substrates (2A, 2B) were heated to 90 degrees, a ferroelectric liquid crystal (CS1029 manufactured by Chisso) was injected between the two substrates by a capillary method. A cable was connected to the electrode connecting portion 3B by ultrasonic soldering, and then only the electrode connecting portion 3B and the solder portion were covered with Kapton tape (manufactured by 3M). As shown in FIG. 10, when an AC voltage of ± 2 kv 60 Hz was applied to the optical deflecting element in which two elements were combined, a continuous optical path shift could be confirmed over the entire effective area.

(A) is sectional drawing of the optical deflection | deviation element concerning this embodiment, (b) is a top view. (A) is sectional drawing of the optical deflection | deviation element concerning this embodiment, (b) is a top view, (c) is a side view, (d) is an enlarged view of an electrode connection part. It is an enlarged view of the electrode connection part of the optical deflection element concerning this embodiment. It is a side view of the light deflection element concerning this embodiment. It is a side view of the light deflection element concerning this embodiment. (A) is sectional drawing of the optical deflection | deviation element concerning this embodiment, (b) is a top view. (A) is sectional drawing of the optical deflection | deviation element concerning this embodiment, (b) is a top view, (c) is a side view, (d) is an enlarged view of an electrode connection part. It is a block diagram which shows the structure of the image display apparatus which has a light deflection element concerning this embodiment. It is a top view of the light deflection element concerning this example. It is the schematic of the conventional optical deflection | deviation element.

Explanation of symbols

2A, 2B Substrate 3A Transparent electrode line group 3B Electrode connection portion 4 Dielectric layer 5 Adhesive layer 6 Spacer 7 Resistor 8 Liquid crystal layer 9 Power source 10 Electric field 11 Power supply means 13 Screen 14 Diffuser plate 15 Condenser lens 16 Transmission type liquid crystal panel 17 Projection lens 18 Light source drive unit 19 Transmission type liquid crystal panel drive unit 20 Optical deflection element 21 Drive unit 22 Cover member 23 Connection line 24 External resistance 25 FPC

Claims (1)

A pair of transparent substrates, a plurality of transparent electrode line groups arranged on the substrate, and a chiral smectic C phase substantially perpendicular to the substrate surface between the substrates in a side view are formed , and ATO (antimony-containing oxidation) A resistor formed in a thickness of approximately 10 μm with a coating type of tin) , disposed between a liquid crystal layer provided with a spacer spaced apart in the side view and the plurality of transparent electrode line groups ; a dielectric layer formed on the resistive element in the side view, and a said resistor for electrically connecting the transparent electrode line group, by generating a potential gradient between the transparent electrode lines In an optical deflection element that deflects an optical path,
The light deflection element, wherein the dielectric layer covers the transparent electrode line group and the resistor.

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