JP2007086143A - Variable focus lens and variable focus mirror - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable focus lens in which the focal length is variable while keeping a desired aspherical shape with a simple structure. <P>SOLUTION: The variable focus lens is provided with: a transparent substrate 32 and a transparent deforming member 33 which are oppositely arranged; a filled layer 35 formed of a transparent material which is filled between the transparent substrate 32 and the transparent deforming member 33; and transparent electrode layers 36 and 37 respectively provided on the surface 32S of the transparent substrate 32 and the surface 33S of the transparent deforming member 33. The transparent deforming member 33 has an elastic constant distribution in the direction along the layer surface. The focal length is varied while keeping the desired aspherical shape with high accuracy by deforming the transparent deforming member 33 according to the elastic constant distribution by applying an electric voltage between the transparent electrode layers 36 and 37. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a variable focus lens and a variable focus mirror that can be adjusted in focal length by deformation.

A microlens array and a microlens array that is an aggregate thereof play an extremely important role in the fields of photolithography, image processing, and optical communication. Recently, in particular, research on lenses capable of dynamic deformation has been advanced. For example, there has been proposed an optical element that obtains a desired focal length by filling a microlens integrated on a microchannel with a liquid and changing the shape of the microlens by applying pressure (Non-patent Document 1). reference). This optical element is formed on a microchannel by patterning on a resist using a semiconductor process and then coating PDMS (polydimethyl-siloxane), and it has a liquid microlens array with variable focal length. ing. Patent Document 1 also discloses a variable focus lens similar to the above optical element. The above-described microlens array and variable focus lens do not change the refractive index of the lens, but change the focal length by changing the outer shape of the lens, such as the thickness of the lens.
Opt-Express, 11, no. 19, pp 2370-2378, 2003 (N. Chronis, GLLiu, KHJeong and LPLee, Opt. Express, 11, No. 19,) JP 2002-131513 A

  However, it is difficult to deform the microlens array and variable focus lens while keeping the outer shape of the lens in an optimum shape. The term “optimal shape” as used herein means a shape in which the occurrence of various wavefront aberrations such as spherical aberration and coma aberration is sufficiently suppressed, and a shape that can favorably correct specific aberrations. Generally, it has an aspherical shape. For example, in the variable focus lens of Patent Document 1, a housing and a transparent sheet that form a liquid-tight space, a light-transmitting liquid that fills the space, and a bottom surface of the housing and an inner surface of the transparent sheet, respectively. And a pair of transparent conductive films provided opposite to each other, and the transparent sheet is deformed by utilizing an attractive force generated by applying a voltage between the pair of transparent electrode films, and as a result, the outer shape of the lens It is comprised so that a shape may change. For this reason, the outer shape of the lens is determined by the elastic constant of the transparent sheet and the applied voltage. Here, since the transparent sheet is presumed to have a uniform composition and a uniform thickness, the transparent sheet at the time of deformation is considered not to be aspherical as a whole but to be spherical. Therefore, when changing the focal length, it may be difficult to sufficiently correct the wavefront aberration of the condensed light flux. In such a case, wavefront aberrations are particularly prominent in lenses having a high NA, which is a serious problem when used for an objective lens of an optical disk system, for example.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a variable focus lens and a variable focus that can change the focal length while forming a desired curved surface shape with high accuracy while having a simple configuration. To provide a mirror.

  The varifocal lens of the present invention comprises a rigid layer made of a transparent material, an elastic layer made of a transparent material disposed so as to face the rigid layer, and a transparent material filled between the rigid layer and the elastic layer. It is provided with a filling layer and a pair of transparent electrode layers provided on one surface of the rigid layer and one surface of the elastic layer, respectively, so that the elastic layer has an elastic constant distribution in a direction along the layer surface. .

  In the variable focus lens of the present invention, the transparent electrode layer pair is provided on one surface of the rigid layer and one surface of the elastic layer. Therefore, when a voltage is applied between the transparent electrode layer pair, the Coulomb force is applied between the transparent electrode layer pair. Is generated, and the rigid layer and the elastic layer are attracted or separated from each other. Here, since the elastic layer has an elastic constant distribution in a direction along the layer surface, the elastic layer is deformed according to the elastic constant distribution.

  The variable focus mirror of the present invention includes a rigid layer, an elastic layer disposed opposite to the rigid layer, a filling layer filled between the rigid layer and the elastic layer, and a rigid layer in the elastic layer. A reflective layer provided on the opposite surface, and electrode layer pairs provided on one surface of the rigid layer and one surface of the elastic layer, respectively, and the elastic layer has an elastic constant distribution in a direction along the layer surface. It is what you have.

  In the variable focus mirror of the present invention, the electrode layer pair is provided on one surface of the rigid layer and one surface of the elastic layer, respectively, so that when a voltage is applied between the electrode layer pair, a Coulomb force is generated between the electrode layer pair, The rigid layer and the elastic layer will be attracted or moved away from each other. Here, since the elastic layer has an elastic constant distribution in a direction along the layer surface, the elastic layer is deformed according to the elastic constant distribution.

  According to the variable focus lens of the present invention, a rigid layer and an elastic layer made of a transparent material that are arranged to face each other, a filling layer made of a transparent material filled between the rigid layer and the elastic layer, and one of the rigid layers A transparent electrode layer pair provided on the surface and one surface of the elastic layer, respectively, and the elastic layer has an elastic constant distribution in the direction along the layer surface, so that a voltage is applied between the transparent electrode layer pair. Then, by deforming the elastic layer according to its own elastic constant distribution, it is possible to change the focal length while ensuring a desired aspherical shape with high accuracy. Accordingly, it is possible to change the focal length while ensuring good aberration performance while having a simple configuration.

  According to the varifocal mirror of the present invention, the rigid layer and the elastic layer arranged to face each other, the reflection layer provided on the surface of the elastic layer opposite to the rigid layer, one surface of the rigid layer and the elasticity Electrode layer pairs provided on one surface of each layer, and the elastic layer has an elastic constant distribution in the direction along the layer surface. By deforming the elastic layer according to the above, the focal length can be changed while ensuring a desired aspherical shape with high accuracy. Accordingly, it is possible to change the focal length while ensuring good aberration performance while having a simple configuration.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
First, a three-dimensional display device 10 (hereinafter referred to as a three-dimensional display device 10A for distinction from a second embodiment described later) as a first embodiment of the present invention will be described. FIG. 1 shows a configuration example of the three-dimensional display device 10A. FIG. 1 is a schematic configuration in a horizontal plane.

  The three-dimensional display device 10A includes a two-dimensional display unit 1 having a plurality of pixels, a collimator unit 2 that converts a wavefront of display image light that diverges from each pixel into a parallel light beam, and a parallel light beam that is converted in the collimator unit 2. Is converted into a wavefront having a curvature that focuses on a position having an optical path length equal to the optical path length from an arbitrary observation point to a virtual object point, and a light beam from the lens array 3 is horizontally converted. A horizontal deflection unit 4 that deflects in the direction and a vertical deflection unit 5 that deflects the light beam from the horizontal deflection unit 4 in the vertical direction are provided.

  FIG. 2A shows a configuration example of a two-dimensional display unit 1 as a two-dimensional image generation unit and a collimator unit 2 as a beam collimating unit. The two-dimensional display unit 1 uses a color liquid crystal device (hereinafter simply referred to as a liquid crystal device) 11 as a display device, and uses a normal fluorescent light as a backlight BL instead of parallel light. The liquid crystal device 11 has a structure in which a glass substrate 12, a pixel electrode 13, and a glass substrate 14 are sequentially laminated. A liquid crystal layer or the like (not shown) is further provided between the two glass substrates 12 and 14. Moreover, the collimating part 2 is comprised by the micro lens 21 which makes | forms convex shape arrange | positioned on the surface 14S of the glass substrate 14, for example. Here, the liquid crystal device 11 emits display image light by irradiating the backlight BL. Since the display image light is a collection of light propagating in all directions, the microlens 21 converts the display image light into a parallel light beam for each pixel.

  As shown in FIG. 2B, a partition wall 22 may be provided instead of the microlens 21 as the collimating unit 2. The partition wall 22 is provided at an intermediate position between the adjacent pixel electrodes 13, and stands vertically (along the Z direction) with respect to the surface 14 </ b> S of the glass substrate 14. In this case, the partition wall 22 is made of a material that absorbs display image light (for example, a resin material in which carbon is dispersed and contained) or a light-absorbing material such as gold black is applied to the surface, so it is unnecessary. The reflected light is cut. Therefore, the display image light emitted from the two-dimensional display unit 1 is restricted from propagating in the in-plane direction parallel to the surface 14S, and propagates in a direction (Z-axis direction) orthogonal to the surface 14S. The partition 22 is provided so as to partition adjacent pixel electrodes 13 not only in the horizontal direction (X-axis direction) but also in the vertical direction (Y-axis direction).

  Further, as shown in FIG. 2C, a collimator unit 2 may include a microlens 21 and a partition wall 22. In this case, the conversion efficiency into a parallel light beam can be increased.

  Further, as shown in FIG. 3A, the partition wall 23 as the collimating unit 2 stands on the surface 12S of the glass substrate 12 (the surface on the side irradiated with the backlight BL) instead of the surface 14S of the glass substrate 14. You may make it install. By doing so, since the backlight BL is converted into a parallel light beam before entering the liquid crystal device 11, the display image light emitted from the liquid crystal device 11 also becomes a parallel light beam.

  Further, in addition to the partition wall 23, the partition wall 22 can be provided on the surface 14S as shown in FIG. In this case, the backlight BL is converted into a parallel light flux by the partition wall 23, and unnecessary light scattered on the glass substrate 14, for example, can be sufficiently removed by the partition wall 22.

  Further, as shown in FIG. 3C, a microlens 21 may be provided in addition to the configuration of FIG. By doing so, display image light collimated more reliably can be obtained.

  Next, the lens array 3 will be described with reference to FIG. FIG. 4 shows a schematic cross-sectional configuration of the lens array 3 as wavefront conversion means.

  As shown in FIG. 4, the lens array 3 has a plurality of variable focus lenses 31. The varifocal lens 31 is an optical device that can arbitrarily change the focal length by deforming a part of itself. Each varifocal lens 31 includes a transparent substrate 32 as a rigid layer, a transparent deformation member 33 as an elastic layer disposed opposite to the transparent substrate 32, and a support provided between the transparent substrate 32 and the transparent deformation member 33. 34, a filling layer 35 filled in a space surrounded by the transparent substrate 32, the transparent deformable member 33 and the support column 34, and transparent electrodes provided on one surface of the transparent substrate 32 and one surface of the transparent deformable member 33 and facing each other. Layers 36 and 37. The transparent electrode layer 36 is grounded, and the transparent electrode layer 37 is connected to an external control power source 38. Furthermore, a communication hole 39 is provided in a part of the support column 34 to allow ventilation to the outside.

  5A and 5B are enlarged views of the variable focus lens 31. FIG. FIG. 5A illustrates a planar configuration, and FIG. 5B illustrates a cross-sectional configuration. FIG. 5B corresponds to a cross section in the direction of the arrow along the VB-VB cutting line of FIG. The transparent substrate 32 is made of a transparent material having high rigidity such as quartz. As with the transparent substrate 32, the support column 34 is also made of a highly rigid material. However, it does not have to be transparent. The transparent deformation member 33 provided on the transparent substrate 32 so as to be supported by the support column 34 is made of a polymer such as a transparent and flexible polyester material, and exhibits a high elastic modulus. Here, the transparent deformation member 33 is gradually thinned from the central portion toward the peripheral portion, for example, in the region where the parallel light flux φ from the collimating portion 2 passes, and the transparent deformable member 33 has a surface 33S on which the transparent electrode layer 37 is provided. The opposite surface 33T forms a convex surface (curved surface). On the other hand, the surface 33S is a plane. Therefore, the transparent deformation member 33 exhibits a function as a lens. Furthermore, since the composition of the polymer constituting the transparent deformable member 33 is substantially uniform, the transparent deformable member 33 has an elastic constant distribution in the in-plane direction (direction in which the XY plane spreads). This elastic constant distribution is caused by the thickness distribution of the transparent deformable member 33. In addition, as a method of molding such a transparent deformable member 33 into a desired shape, for example, a method using an injection mold used as a means for molding a normal plastic lens or optical disk substrate may be used, or an excimer racer may be used. Alternatively, a desired location on the surface of the polymer substrate may be partially evaporated by using an infrared laser such as a UV laser or a carbon dioxide gas laser. Alternatively, by using a normal reactive ion etching apparatus (RIE: Reactive Ion Etching) or ion milling apparatus by a normal semiconductor process, a desired amount of the substrate surface is partially vapor-phase etched (dry etching). May be applied. Furthermore, a method using hot embossing or stamp molding may be used. On the other hand, the support 34 may be molded as an integral part of the transparent substrate 32 by cutting out from a base material such as quartz using a powder beam etching device or an RIE device, for example. Or you may make it stick the support | pillar 34 produced separately on the transparent substrate 32. FIG.

  The transparent electrode layers 36 and 37 are made of a conductive polymer in which a metal such as gold or silver or carbon is dispersed in a non-conductive plastic such as polyolefin and processed into a sheet shape, and the surface 32S of the transparent substrate 32 and the transparent deformation are respectively formed. It is affixed to the surface 33S of the member 33 with a transparent adhesive. Alternatively, a conductive material such as carbon or ITO (Indium Tin Oxide) is applied to the surfaces 32S and 33S, and a vacuum deposition apparatus, a sputtering apparatus, an ion plating apparatus, or a CVD (chemical chemical vapor deposition apparatus). The transparent electrode layers 36 and 37 may be deposited directly using a chemical vapor deposition apparatus or the like. Further, it may be produced by applying ultra-fine carbon or a conductive material such as gold or silver dispersed in a predetermined organic solvent or aqueous solution using a spin coater. The transparent electrode layer 36 is grounded via a connection line 36T, and the transparent electrode layer 37 is connected to an external control power source 38 via a connection line 37T.

  The filling layer 35 is made of a transparent and extremely flexible fluid material such as silicone. The filling layer 35 is filled only in a partial region including at least a region through which the parallel light flux φ passes among regions sandwiched between the transparent substrate 32 and the transparent deformation member 33. The other area is secured as a buffer area having a communication hole 39 connected to the external space. However, the filling layer 35 is provided so as to completely cover the transparent electrode layers 36 and 37.

  In the varifocal lens 31 having such a configuration, when a voltage of a predetermined magnitude is applied between the transparent electrode layer 36 and the transparent electrode layer 37 by the external control power supply 38, the transparent electrode layer 36, the transparent electrode layer 37, During this period, electrostatic force (Coulomb force) is generated and attracts each other. The transparent electrode layer 36 is fixed to the surface 32S of the transparent substrate 32, and one transparent electrode layer 37 is fixed to the surface 33S of the transparent deformation member 33. As a result, the transparent substrate 32 and the transparent deformation member 33 Will attract each other. At this time, since the transparent substrate 32 is made of a material having a relatively high rigidity, it hardly deforms. On the other hand, since the transparent deformation member 33 is made of a material exhibiting high elasticity, a relatively large deformation occurs. Since the transparent deformation member 33 is deformed according to the elastic constant distribution defined by its thickness distribution, a desired lens action can be obtained by designing and processing in advance so as to form a desired shape after the deformation. it can. At this time, by using the fact that the electrostatic force changes according to the magnitude of the applied voltage between the transparent electrode layer 36 and the transparent electrode layer 37, the transparent deformation members 33 that are different continuously (or stepwise). Select and form the shape. The thickness distribution of the transparent deformable member 33 can be optimized based on, for example, a simulation result by a finite element method (FEM). Accordingly, it is possible to realize the variable focus lens 31 that can change the focal length while maintaining a desired spherical shape or aspherical shape. The packed layer 35 is also deformed as the shape of the transparent deformable member 33 is changed. However, since the air in the buffer region is discharged to the outside through the communication hole 39, the deformation is performed smoothly.

  Here, the operation of the varifocal lens 31 will be described in more detail with reference to FIGS. 6 (A) and 6 (B). Here, in order to facilitate understanding, a case where all the refractive indexes of the transparent substrate 32, the transparent deformation member 33, and the filling layer 35 are equal will be described. However, in the present invention, the refractive indexes of these members may be different from each other, and an optical action that positively utilizes the difference in the refractive indexes may be obtained. FIG. 6A shows an initial state in which no voltage is applied between the transparent electrode layers 36 and 37. At this time, the shape of the surface 33T on the incident side of the transparent deformable member 33 is not parallel to the surface 32T on the emission side of the transparent substrate 32, and is convex on the incident side. For this reason, the variable focus lens 31 acts as a convex lens and exhibits the function of focusing the incident light flux Φ. On the other hand, FIG. 6B shows a state where a predetermined voltage is applied between the transparent electrode layers 36 and 37. By applying voltage, an electrostatic force acts between the transparent electrode layers 36 and 37, the transparent deformable member 33 and the filling layer 35 are deformed, and the surface 33T is concave. At this time, the surface 32T remains flat. Therefore, in this case, the varifocal lens 31 acts as a concave lens and exhibits the function of diverging the incident light flux Φ. Here, since the transparent deformation member 33 has a predetermined thickness distribution (elastic constant distribution), the shape of the surface 33T is appropriately selected by adjusting the applied voltage. Therefore, the wavefront aberration is corrected well while changing the focal length.

  Further, the optical action is not exhibited when no voltage is applied, and negative refractive power can be obtained when a voltage is applied as follows. FIG. 7A shows an initial state in which no voltage is applied between the transparent electrode layers 36 and 37. At this time, the shape of the surface 33T on the incident side of the transparent deformation member 33 is substantially parallel to the surface 32T on the emission side of the transparent substrate 32. For this reason, the incident light flux Φ is transmitted without receiving any optical action. That is, the varifocal lens 31 has substantially the same function as that of flat glass. On the other hand, FIG. 7B shows a state where a predetermined voltage is applied between the transparent electrode layers 36 and 37. By applying voltage, an electrostatic force acts between the transparent electrode layers 36 and 37, the transparent deformable member 33 and the filling layer 35 are deformed, and the surface 33T is concave. At this time, the surface 32T remains flat. Therefore, in this case, the varifocal lens 31 acts as a concave lens and exhibits the function of diverging the incident light flux φ. Here, since the transparent deformation member 33 has a predetermined thickness distribution (elastic constant distribution), a desired concave shape can be selected by adjusting the applied voltage. Therefore, the wavefront aberration is corrected well while the focal length is changed.

  Next, the horizontal deflection unit 4 and the vertical deflection unit 5 will be described with reference to FIGS. 8A and 8B. FIG. 8A shows a planar configuration of the horizontal deflection unit 4, and FIG. 8B shows a cross-sectional configuration of the horizontal deflection unit 4 in the arrow direction along the VIIB-VIIB cutting line. Since the configuration of the vertical deflection unit 5 is the same as that of the horizontal deflection unit 4 described below, the description thereof is omitted here.

  The horizontal deflection unit 4 includes a plurality of light deflection elements 41 arranged in parallel with each other. 8A and 8B show six light deflection elements 41, the number may be increased or decreased as necessary. The light deflection element 41 is a transmission type deflection element, and is disposed between the transparent substrate 42, the movable layer 43 made of a transparent material and facing the transparent substrate 42, and between the transparent substrate 42 and the movable layer 43. A filling layer 45 made of a filled transparent material, a transparent electrode layer pattern 46, and transparent electrode layer patterns 47A and 47B are included. Here, the transparent substrate 42 and the transparent electrode layer pattern 46 are provided in common for the plurality of light deflection elements 41.

  The transparent substrate 42 is made of a transparent material having high rigidity such as quartz. In the central region of the transparent substrate 42, a strip-shaped laminate of the movable layer 43 and the filling layer 45 is arranged, and the peripheral region surrounding it has a thickness similar to that of the filling layer 45. A support body 44 is provided as a laminated body of the support 44 </ b> A and a support frame 44 </ b> B having a thickness similar to that of the movable layer 43. The movable portion 43 is a parallel plate having high rigidity such as quartz, and is in a state of being connected to the support frame 44B via a pair of hinges 43T respectively connected to both ends in the longitudinal direction. As shown in FIG. 9, the movable portion 43 has a structure in which, for example, a quartz substrate having a thickness of 20 μm is integrally formed with the surrounding support frame 44B and the hinge 43T by etching. FIG. 9 is a plan view illustrating the structure of the movable portion 43, the hinge 43T, and the support frame 44B. In the movable portion 43, the length 43L is 1 mm, for example, and the width 43W is 0.1 mm, for example. Each of the pair of hinges 43T has one end connected to the end of the movable portion 43 and the other end connected to the support frame 44B, and is formed so as to be positioned in the same straight line. The hinge 43T has an elongated shape along the longitudinal direction of the movable portion 43, and has a length 43TL of 0.2 mm, for example, and a width 43TW of 0.01 mm, for example. For this reason, by applying some external force, the movable portion 43 can rotate around the rotation axis along the extending direction of the hinge 43T. Here, since the filling layer 45 is made of a transparent and extremely flexible fluid material such as silicone, it does not hinder the operation of the movable layer 43 as it rotates.

  The rotating operation of the movable layer 43 is performed using an electrostatic force generated by applying a voltage between the transparent electrode layer pattern 46 and the transparent electrode layer patterns 47A and 47B. The transparent electrode layer pattern 46 is provided so as to cover at least a region corresponding to the movable portion 43 on the surface 42S of the transparent substrate 42, and is grounded by a connection line (not shown). On the other hand, the transparent electrode layer patterns 47A and 47B are formed on the surface 43S of the movable portion 43 so as to face the transparent electrode layer pattern 46, and extend along the hinge 43T, so that the external control power supplies 48A and 48B (rear) And are connected respectively. Accordingly, the transparent electrode layer patterns 47A and 47B are individually paired with the transparent electrode layer pattern 46, and an electrostatic force is generated between them by voltage application. Further, the transparent electrode layer patterns 47A and 47B are opposed to each other at the edge extending in the longitudinal direction (Y-axis direction) of the movable layer 43 and from the intermediate position in the longitudinal direction of the movable layer 43 so as to have the same shape. It is formed so that the width gradually increases toward both ends. The transparent electrode layer pattern 46 and the transparent electrode layer patterns 47A and 47B are made of, for example, a conductive material such as carbon or ITO using a vacuum deposition apparatus, a sputtering apparatus, an ion plating apparatus, a CVD apparatus, or the like, which is a general vacuum film forming apparatus. Is directly deposited on the surfaces 42S and 43S. In FIG. 8A, for easy understanding, the portions where the transparent electrode layer patterns 47A and 47B are formed are shown with a pattern, and the outline thereof is indicated by a solid line. In this embodiment, the common transparent electrode layer pattern 46 is provided on the surface 42S of the transparent electrode 42. However, the transparent electrode layer pattern 46 is individually provided on the surface 43S of each movable layer 43. May be. In that case, the transparent electrode layer patterns 47A and 47B may be provided on the surface 42S. In the present embodiment, the transparent electrode layer pattern 46 is provided in common for both of the transparent electrode layer patterns 47A and 47B. However, the transparent electrode layer pattern 46 is divided into a plurality of parts, and the transparent electrode layer pattern 47A is provided. , 47B may be individually supported.

  Here, the operation of the light deflection element 41 will be described in detail with reference to FIGS. 10A to 10C are schematic diagrams for explaining the operation and optical action of the light deflection element 41. FIG. In the light deflection element 41, a voltage having a predetermined magnitude is applied between the transparent electrode layer pattern 46 and the transparent electrode layer patterns 47A and 47B by using the external control power supplies 48A and 48B, thereby extending along the X axis. An electric field strength distribution is formed in the direction. For example, a voltage is applied between the transparent electrode layer pattern 46 and the transparent electrode layer pattern 47A to generate an electrostatic force, and a voltage is applied between one transparent electrode layer pattern 46 and the transparent electrode layer pattern 47B. Otherwise, a torque is generated with the central axis ω43 of the pair of hinges 43T as the rotation axis, and the movable layer 43 rotates in the direction in which the transparent electrode layer pattern 46 and the transparent electrode layer pattern 47A are attracted. At this time, the hinge 43T is twisted. When the voltage supply between the transparent electrode layer pattern 46 and the transparent electrode layer pattern 47A is stopped in the state of FIG. 10A, the electrostatic force is lost, and the movable layer 43 becomes transparent electrode layer pattern 46 by the restoring force of the hinge 43T. That is, it is in a state parallel to (that is, the transparent substrate 42) (FIG. 10B). Further, no voltage is applied between the transparent electrode layer pattern 46 and the transparent electrode layer pattern 47A, and an electrostatic force is generated by applying a voltage between the transparent electrode layer pattern 46 and the transparent electrode layer pattern 47B. Then, the movable layer 43 rotates in the direction in which the transparent electrode layer pattern 46 and the transparent electrode layer pattern 47B are attracted (FIG. 10C). Here, the rotation angle of the movable layer 43 can be controlled by adjusting the magnitude of the applied voltage. That is, the rotation angle between FIGS. 10A and 10B and the rotation angle between FIGS. 10B and 10C can be realized.

  Next, the optical action of the light deflection element 41 will be described. Here, a case where a light beam enters from the movable layer 43 side is considered. In FIG. 10A, the incident light beam is inclined downward to the left. Usually, each constituent material of the light deflection element 41 has a refractive index larger than that of the atmosphere, so that the light beam incident on the movable layer 43 is refracted in the right direction. After that, the light beam sequentially transmitted through the filling layer 45, the transparent electrode layer pattern 46, and the transparent substrate 42 is further refracted in the right direction when emitted to the outside. As a result, the incident light beam is deflected in the right direction. The deflection angle at this time depends on the rotation angle (tilt angle) of the movable layer 43. That is, it depends on the magnitude of the voltage applied between the transparent electrode layer pattern 46 and the transparent electrode layer pattern 47A. Furthermore, the deflection angle is adjusted by appropriately selecting the refractive index of each constituent material of the optical deflection element 41. For example, when the filling layer 45 has a refractive index n45 (= 2 × n43) that is twice the refractive index n43 of the movable layer 43, the deflection angle is twice as large as the rotation angle of the movable layer 43. Will be obtained. On the other hand, in FIG. 10C, since it is inclined downward to the right with respect to the incident light beam, it is deflected to the left, contrary to the case of FIG. The adjustment of the deflection angle is the same as in the case of FIG. Thus, the light deflection element 41 can function as a prism. In the state shown in FIG. 10B, the incident light beam travels straight without receiving any deflection action. In FIGS. 10A to 10C, the illustration of the transparent substrate 42 is omitted, so that the light flux is drawn from the lower surface of the transparent electrode layer pattern 46. Emits light from the lower surface of the transparent substrate 42.

  The light deflection element 41 that exhibits such an optical action can individually select the rotation angle of the movable layer 43 by individually controlling the applied voltage. Therefore, as shown in FIG. 11, each light deflection element 41 constituting the horizontal deflection unit 4 can deflect the incident light beam to a desired angle.

  The vertical deflection unit 5 includes a plurality of optical deflection elements 51 having the same configuration as the optical deflection element 41 in the horizontal deflection unit 4. As shown in FIG. 12, the light deflection elements 41 and 51 are arranged so that the movable parts 43 and 53 are superposed so as to be orthogonal to each other. With such a configuration, it is possible to easily perform the deflection operation in both the horizontal direction and the vertical direction, which has been difficult to realize with a conventional reflective optical deflection element.

<Operation of 3D display device>
Next, the operation of the three-dimensional display device 10A will be described with reference to FIGS.

  In general, when an observer observes an object point on a certain object, it recognizes it as a “point” that exists in a unique place in a three-dimensional space by observing a spherical wave emitted using that object point as a point light source. is doing. Usually, in the natural world, wavefronts emitted from an object travel simultaneously and always reach the observer with a certain wavefront shape. However, at present, it is difficult to simultaneously and continuously reproduce the wavefront of the light wave at each point in space, except for the holography technique. However, even if there is a virtual object, light waves from each virtual point are emitted, and even when the time when each light wave reaches the observer is somewhat inaccurate, it is not continuous, but intermittent. Even if it arrives as a typical optical signal, the human eye can observe a virtual object without feeling an unnatural sensation due to this integration action. In the three-dimensional display device 10A according to the present embodiment, the wave front of each point in space is formed in a time series and at a high speed by utilizing the integral action of the human eye, thereby providing a natural three-dimensional display. An image can be formed.

  FIG. 13 is a conceptual diagram showing a state in which the observers I and II are observing the virtual object IMG as a stereoscopic image using the three-dimensional display device 10A. The operation principle will be described below.

  For example, an image light wave of an arbitrary virtual object point (for example, virtual object point B) in the virtual object IMG is formed as follows. First, two types of images corresponding to the left and right eyes are displayed on the two-dimensional display unit 1. Of course, since it is impossible to display two images at the same time, the images are sequentially displayed and finally sent sequentially to the left and right eyes, respectively. For example, images corresponding to the virtual object point C are displayed at the point CL1 (for the left eye) and the point CR1 (for the right eye) in the two-dimensional display unit 1, respectively, and the collimator unit 2, the lens array 3, and the horizontal direction After sequentially passing through the deflecting unit 4 and the vertical direction deflecting unit 5, the left eye IIL and the right eye IIR of the observer II are respectively reached. Similarly, the image of the virtual object point C for the observer I is displayed at the point BL1 (for the left eye) and the point BR1 (for the right eye) in the two-dimensional display unit 1, respectively, and the collimating unit 2, the lens array 3, and the horizontal direction After sequentially passing through the deflecting unit 4 and the vertical direction deflecting unit 5, the left eye IL and the right eye IR of the observer I are respectively reached. Since this operation is performed at high speed within the time constant of the integral effect of the human eye, the observers I and II do not recognize that images are being sent sequentially but recognize the virtual object point C. Can do.

  The display image light emitted from the two-dimensional display unit 1 is converted into a substantially parallel light beam by the collimator unit 2 and then travels to the lens array 3. The collimator unit 2 converts the display image light into a parallel light flux and makes the focal length infinite, thereby obtaining information obtained from physiological functions generated when adjusting the focal length of the eye among the positional information of the point where the light wave is emitted. Is turned off once. In FIG. 13, the wavefront of the light beam traveling from the collimator 2 to the lens array 3 is shown as a parallel wavefront r0 orthogonal to the traveling direction. As a result, the brain confusion caused by the fact that the information from the binocular parallax / angle of convergence and the information from the focal length do not coincide with each other can be alleviated. Thereafter, in the lens array 3, focal length information corresponding to each pixel is added. This will be described in detail later.

  The display image light emitted from the points CL1 and CR1 of the two-dimensional display unit 1 passes through the lens array 3 and then reaches the points CL2 and CR2 of the horizontal direction deflection unit 4, respectively. The light wave that has reached the points CL2 and CR2 of the horizontal deflection unit is deflected in a predetermined direction within the horizontal plane, and then reaches the points CL3 and CR3 of the vertical direction deflection unit 5. Further, the light is deflected in a predetermined direction within the vertical plane by the vertical deflection unit 5 and emitted toward the left eye IIL and the right eye IIR of the observer II, respectively. Here, for example, when the deflection angle is directed to the left eye IIL of the observer II, the wavefront of the display image light reaches the point CL3, and when the deflection angle is directed to the right eye IIR of the observer II, the display image light is displayed. The two-dimensional display unit 1 sends out display image light in synchronism with the deflection angles of the horizontal direction deflection unit 4 and the vertical direction deflection unit 5 so that the wavefront reaches the point CR3. At this time, the lens array 3 performs the wavefront conversion operation in synchronization with the deflection angles of the horizontal deflection unit 4 and the vertical deflection unit 5. When the wavefront of the display image light radiated from the vertical deflection unit 5 reaches the left eye IIL and the right eye IIR of the observer II, the observer II places the virtual object point C on the virtual object IMG in the three-dimensional space. It can be recognized as one point. Similarly for the virtual object point B, the display image light emitted from the points BL1 and BR1 of the two-dimensional display unit 1 passes through the lens array 3 and then reaches the points BL2 and BR2 of the horizontal deflection unit 4, respectively. The light waves that have reached the points BL2 and BR2 are deflected in a predetermined direction in the horizontal plane, and then are deflected in a predetermined direction in the vertical plane by the vertical direction deflecting unit 5 toward the left eye IIL and the right eye IIR of the observer II, respectively. Is emitted. In FIG. 13, the image of the virtual object point C for the observer I and the image of the virtual object point B for the observer II are displayed at the points BL1 and BR1 of the two-dimensional display unit 1. However, they are not displayed at the same time, but at different timings.

  Here, the operation of the lens array 3 will be described with reference to FIG. 14 in addition to FIG. In the lens array 3, the wavefront r0 of the display image light emitted from the two-dimensional display unit 1 has a curvature that focuses on a position where the optical path length is equal to the optical path length from an arbitrary observation point to a virtual object point. Converted to wavefront r1. For example, as shown in FIG. 14, when the wavefront RC of light emitted from the virtual object point C as the light source reaches the left eye IIL via the optical path length L1, the wavefront RC and wavefront r1 in the left eye IIL Wavefronts are formed so that the curvatures of the two coincide with each other. In this case, it can be considered that the focal point CC corresponding to the wavefront r1 exists at a distance equal to the optical path length L2 from the point CL2 to the virtual object point C on the straight line connecting the point CL2 and the point CL1. Therefore, assuming that the display image light having the wavefront r1 is emitted with the focal point CC as the light source, when the wavefront r1 of the display image light reaches the left eye IIL, it is emitted with the virtual object point C as the light source. It is recognized as if the wavefront RC was made. As shown in FIG. 13, when the virtual object point A exists at a position closer to the observer side than the vertical deflection unit 5, the wavefront r <b> 1 converted by the lens array 3 is focused on the virtual object point A. Will be tied.

  As a result, the confusion of the brain caused by the discrepancy between the information from the binocular parallax / convergence angle and the information from the focal length, which has been generated conventionally, is completely eliminated.

  Further, by converting the display image light radiated from the two-dimensional display unit 1 into the collimated light beam by the collimating unit 2, the following operation can be obtained. In order to ensure binocular parallax, it is necessary to send two types of images corresponding to the left and right eyes. That is, the display image lights corresponding to the left and right eyes must not enter the eyes on the opposite sides. If the collimator unit 2 does not exist and spherical waves are emitted from the two-dimensional display unit 1 as a light source, even if they are deflected by the horizontal deflection unit 4 and the vertical deflection unit 5, they are opposite to each other. Unnecessary display image light also enters the eyes. In that case, binocular parallax does not occur and the image is recognized as a double image. Therefore, if the display image light from the two-dimensional display unit 1 is converted into a parallel light beam in the collimator unit 2 as in the present embodiment, the display image light does not spread in a fan shape, and therefore the other Only one target eye can be reached without entering the eye.

  As described above, according to the three-dimensional display device 10A of the present embodiment, the two-dimensional display unit 1 generates two-dimensional image light corresponding to the video signal, and the lens array 3 emits the light from the two-dimensional display unit 1. The wavefront r0 of the displayed display image light is converted into a wavefront r1 having a curvature that connects the focal point CC having an optical path length equal to the optical path length L1 from an arbitrary observation point (left eye IIL) to the virtual object point C. Therefore, the display image light includes not only information regarding binocular parallax, convergence angle and motion parallax but also appropriate focal length information. For this reason, the observer can aim for consistency between the information regarding the binocular parallax, the convergence angle, and the motion parallax and the appropriate focal length information, and recognizes a desired stereoscopic image without causing a physiological discomfort. be able to. In particular, in addition to the deflection operation in the horizontal plane by the horizontal deflection unit 4, the deflection operation in the vertical plane by the vertical deflection unit 5 is also performed, so that the virtual line connecting the eyes of the observer is in the horizontal direction. Even when the user is out of the range (when the observer takes a lying posture), a predetermined image reaches the left and right eyes, so that stereoscopic viewing is possible.

  Since the lens array 3A composed of a plurality of variable focus lenses 31 is used as the lens array 3, the following effects can be obtained. That is, each variable focus lens 31 is placed on the transparent substrate 32 and the transparent deformation member 33 arranged opposite to each other, the filling layer 35 filled therebetween, the surface 32S of the transparent substrate 32, and the surface 33S of the transparent deformation member 33. Since the transparent deformable member 33 has the elastic constant distribution defined by the thickness distribution in the direction along the layer surface, the transparent electrode layers 36 and 37 are provided. By applying a voltage between them and deforming the transparent deformable member 33 according to the elastic constant distribution, the focal length can be changed while ensuring a desired aspherical shape with high accuracy. Accordingly, it is possible to change the focal length while ensuring good aberration performance while having a simple and compact configuration.

  Further, in the horizontal deflection unit 4 and the vertical deflection unit 5, the transparent substrate 42 and the movable layer 43 arranged to face each other, the filling layer 45 filled therebetween, the surface 42S of the transparent substrate 42 and the movable layer Transmissive optical deflection elements 41 and 51 each having a transparent electrode layer pattern 46 and transparent electrode layer patterns 47A and 47B that are respectively provided on the surface 43S of 43 and form an electric field strength distribution in the direction along the layer surface. Therefore, the deflection operation in both the horizontal direction and the vertical direction can be easily performed while achieving a sufficiently compact configuration as a whole as compared with the case of using the reflective light deflection element.

  In addition, since all of the lens array 3, the horizontal deflection unit 4, and the vertical deflection unit 5 employ transmission devices, it is very easy to make the entire configuration of the three-dimensional display device 10A compact (thinner). It is feasible.

<Modified example of variable focus lens>
Next, a modification of the present embodiment will be described. In the present embodiment, the transparent deformable member 33 in the variable focus lens 31 has a thickness distribution, and a desired lens shape is formed using an elastic constant distribution defined thereby. On the other hand, for example, as in the variable focus lenses 31B, 31C, and 31D as the first to third modified examples (modified examples 1 to 3) shown in FIGS. It is also possible to form a desired lens shape by giving an intensity distribution and using this.

  First, the variable focus lens 31B as Modification 1 will be described. FIG. 15A illustrates a planar configuration of the variable focus lens 31B, and FIG. 15B illustrates a cross-sectional configuration of the variable focus lens 31B. Here, FIG. 15B corresponds to a cross-section in the direction of the arrow in the XVB-XVB cutting line of FIG. The variable focus lens 31B has a transparent electrode layer pattern 36A having a circular shape at the center position on the surface 32S, and an annular transparent electrode layer pattern 36B having the same concentricity with the transparent electrode layer pattern 36A. The transparent electrode layer patterns 36A and 36B are insulated from each other and are grounded. The variable focus lens 31B has the same configuration as the variable focus lens 31 shown in FIGS. 5A and 5B except for the above points.

  In the variable focus lens 31B, a voltage can be applied independently to each of the transparent electrode layer pattern 36A and the transparent electrode layer pattern 36B. Therefore, the shape of the transparent deformable member 33 is controlled by controlling each applied voltage. be able to. For example, when deforming from a state functioning as a convex lens to a state functioning as a concave lens, a voltage is applied only to the electrode of the transparent electrode layer pattern 36A disposed at the center position. Further, by adjusting the balance between the voltage applied to the transparent electrode layer pattern 36A and the voltage applied to the transparent electrode layer pattern 36B disposed so as to surround the transparent electrode layer pattern 36A, it can be smoothly deformed into a desired aspherical surface. it can. In this example, only the transparent electrode layer on the transparent substrate 32 side is divided, and the transparent electrode layer 37 on the transparent deformable member 33 side is not divided, but it matches the shape of the transparent electrode layer patterns 36A and 36B. Alternatively, the transparent electrode layer 37 may be divided. Alternatively, only the transparent electrode layer 37 on the transparent deformation member 33 side may be divided and arranged.

  Next, a variable focus lens 31C as Modification 2 will be described. FIG. 16A illustrates a planar configuration of the variable focus lens 31C, and FIG. 16B illustrates a cross-sectional configuration of the variable focus lens 31C. Here, FIG. 16B corresponds to a cross-section in the direction of the arrows along the XVIB-XVIB cutting line of FIG. The variable focal length lens 31C has transparent electrode layer patterns 36B to 36E that are evenly arranged on the surface 32S so as to surround the transparent electrode layer pattern 36A. The transparent electrode layer patterns 36B to 36E are insulated from each other and are grounded. The variable focus lens 31C has the same configuration as the variable focus lens 31 shown in FIGS. 5A and 5B except for the above points. By using the transparent electrode layer patterns 36 </ b> B to 36 </ b> E arranged in this way, an asymmetric deformation operation in the transparent deformation member 33 can be performed. Therefore, it is suitable for correcting coma aberration, for example.

  Next, a variable focus lens 31D as Modification 3 will be described. FIG. 17A illustrates a planar configuration of the variable focus lens 31D, and FIG. 17B illustrates a cross-sectional configuration of the variable focus lens 31D. Here, FIG. 17B corresponds to a cross-section in the direction of the arrow in the XVIIB-XVIIB cutting line of FIG. In the variable focus lens 31D, the surface 32S of the transparent substrate 32 is not a flat surface but a curved surface (here, a concave surface). Therefore, since the transparent electrode layer pattern 36 formed on the surface 32S has a curved surface, the relative distance between the transparent electrode layer pattern 36 and the transparent electrode layer pattern 37 arranged opposite to each other has a distribution. Thereby, the attractive force due to the electrostatic force is weakened in the central portion, and the attractive force in the peripheral portion is relatively strong. By utilizing this intensity distribution, a desired aspheric shape can be formed. In this case as well, at least one of the transparent electrode layer patterns 36 and 37 may be divided and arranged.

[Second Embodiment]
Next, a 3D display device 10B as a second embodiment of the present invention will be described. In the first embodiment, a variable focus lens is used as the wavefront conversion means. However, in this embodiment, a variable focus mirror is used.

  FIG. 18 is a conceptual diagram illustrating the overall configuration of the three-dimensional display device 10B. As shown in FIG. 18, the three-dimensional display device 10B includes a two-dimensional display unit 1, a collimator unit 2, a mirror array 6 as wavefront conversion means, and a deflection mirror 4B as deflection means in order. It is a thing.

  The mirror array 6 has a plurality of variable focus mirrors 61 as shown in FIG. FIG. 19 shows a schematic cross-sectional configuration of the mirror array 6. Similar to the variable focus lens 31, the variable focus mirror 61 is an optical device that can arbitrarily change the focal length by deforming a part thereof. Each varifocal mirror 61 includes a substrate 62 as a rigid layer, a reflective deformation member 63 as an elastic layer disposed opposite to the substrate 62, and a column 64 provided between the substrate 62 and the reflective deformation member 63. And electrode layers 66 and 67 provided on one surface of the substrate 62 and one surface of the reflective deformation member 63, respectively, and a filling layer 65 filled between the electrode layers 66 and 67. Yes. The electrode layer 66 is grounded, and the electrode layer 67 is connected to an external control power source 68. Furthermore, a communication hole 69 is provided in a part of the support column 64 so that the outside can be ventilated.

  The substrate 62 is made of a material having high rigidity such as quartz. As with the substrate 62, the support column 64 is also made of a highly rigid material. The reflective deformation member 63 provided so as to be supported by the support column 64 on the substrate 62 is made of a polymer such as a flexible polyester material and exhibits a high elastic modulus. Further, a reflective film 63M made of a thin film such as silver (Ag) and a protective film (not shown) for protecting the reflective film 63M are sequentially laminated on the surface 63S opposite to the substrate 62. The reflective film 63M is formed by, for example, a sputtering method, and the incident light flux φ is reflected by the reflective surface 63MS that is the surface thereof. Here, the reflective deformation member 63 is gradually thinned from the central part to the peripheral part in the region where the parallel light flux φ from the collimating part 2 is reflected, so that it is elastic in the in-plane direction in which it extends. It will have a constant distribution. Further, when the surface 63S has a curved surface, the lens action is also exhibited. Such a reflective deformable member 63 can be molded by the same method as the transparent deformable member 33.

  The electrode layers 66 and 67 can have the same configuration as the transparent electrode layers 36 and 37. However, it is not limited to a transparent material.

  The filling layer 65 has the same properties as the filling layer 35 in the first embodiment (for example, silicone). Note that the reflective deformation member 63 may be deformed by using an electrostatic force acting between the electrode layers 66 and 67 without providing the filling layer 65. However, if the filling layer 65 is provided, the dielectric constant between the electrode layers 66 and 67 is improved and the dielectric breakdown characteristics are stabilized, so that a more efficient and reliable wavefront forming operation can be performed.

  The variable focus mirror 61 having such a configuration collects or diverges while reflecting incident light. Alternatively, it is possible to perform only the reflection with the parallel light flux without exhibiting such a lens action. Specifically, when a voltage having a predetermined magnitude is applied between the electrode layer 66 and the transparent electrode layer 67 by the external control power supply 68, an electrostatic force is generated between them and attracts each other. The electrode layer 66 is fixed to the surface 62S of the substrate 62, and the one electrode layer 67 is fixed to the surface 63S of the reflective deformation member 63. As a result, the substrate 62 and the reflective deformation member 63 are mutually connected. Will attract each other. At this time, since the substrate 62 is made of a material having a relatively high rigidity, it hardly deforms. On the other hand, since the reflective deformation member 63 is made of a material exhibiting high elasticity, a relatively large deformation occurs. Since the reflective deformation member 63 is deformed according to the elastic constant distribution defined by its thickness distribution, a desired lens action is obtained by designing and processing in advance so as to form a desired shape after the deformation. Can do. At this time, by using the fact that the electrostatic force changes according to the magnitude of the applied voltage between the electrode layer 66 and the electrode layer 67, the shapes of the reflective deformation members 63 that are continuously (or stepwise) different. (That is, the shape of the reflective surface 63MS) can be selectively formed. In FIG. 19, the state where the reflecting surface 63MS has a concave surface and exhibits a condensing function is the variable focus mirror 61A, and the state where the reflecting surface 63MS has a convex surface and exhibits a diverging action is the variable focus mirror 61B. The state where the reflecting surface 63MS is flat and only reflects without exhibiting the lens action is the variable focus mirror 61C. Note that the thickness distribution of the reflective deformation member 63 can be optimized based on, for example, a simulation result by a finite element method. Thereby, it is possible to realize the variable focus mirror 61 that can change the focal length while maintaining a desired spherical shape or aspherical shape.

  As the deflection mirror 4B, for example, a galvanometer mirror can be used. Although FIG. 18 shows an example in which three galvanometer mirrors are arranged, the number may be two or less, or may be four or more if necessary. Further, it may be a scanning micromirror array element in which a large number of deflectable micromirrors such as a DMD (digital multimirror) are arranged.

  Next, with reference to FIG. 18 and FIG. 19, the operation principle in the case of observing a virtual object IMG as a stereoscopic image using the three-dimensional display device 10B having such a mirror array 6 and the deflecting mirror 4B will be described. explain.

  When a wavefront of display image light corresponding to the virtual object point B of the virtual object when viewed with the right eye IR of the observer I is emitted from the specific display area of the two-dimensional display unit 1 through the collimator unit 2 To do. The display image light is reflected by the variable focus mirror 61 of the mirror array 6. At this time, the display image light is converted into a wavefront having a desired curvature by controlling the shape of the surface 63S (that is, the surface of the reflective film 63M). Here, the light wave generated at the virtual object point B (that is, a spherical wave having the virtual object point B as a light source) is converted into a wavefront that has a curvature (focal length) felt by the observer when it reaches the observer. . That is, the optical path length from the virtual object point B to the right eye IR of the observer I is made to coincide with the optical path length from the focal point BB of the display image light reflected by the mirror array 6 to the right eye IR of the observer I. The shape of the surface 63S may be controlled. The display image light reflected by the mirror array 6 reaches the point d on the deflection mirror 4B when the deflection mirror 4B is directed in the direction of the right eye IR of the observer I, and is incident on the right eye IR. Similarly, when the wavefront of the display image light corresponding to the virtual object point B when viewed with the left eye IL of the observer I is emitted from another specific display area in the two-dimensional display unit 1, the display image After passing through the mirror array 6, the light reaches the point c on the deflecting mirror 4 </ b> B when the deflecting mirror 4 </ b> B is directed in the direction of the left eye IL of the observer I, and is incident on the left eye IL.

  Through the above process, the observer I observes the virtual object point B on the virtual object IMG with both eyes. At this time, the observer I recognizes the virtual object point B at the intersection of the straight line connecting the left eye IL and the point c and the straight line connecting the right eye IR and the point d. Similarly, the observer I also regards another virtual object point A on the virtual object IMG as a point on the space at the intersection of the straight line connecting the left eye IL and the point a and the straight line connecting the right eye IR and the point b. recognize. Further, all other virtual object points (not shown) can be recognized through the same process.

  As described above, also in the three-dimensional display device 10B of the present embodiment, the observer can achieve consistency between the information regarding the binocular parallax, the convergence angle, and the motion parallax and the appropriate focal length information. It is possible to recognize a desired stereoscopic image without causing a sense of incongruity.

  Next, examples of the present invention will be described below.

  In this example, a variable focus lens 31E of the present invention having the structure shown in FIG. 20 was produced and its characteristics were evaluated.

  As shown in FIG. 20, in the varifocal lens 31E according to the present embodiment, a transparent deformable member 33E and a support post 34E, which are gradually reduced in thickness from the center position CL, are integrally formed. The planar shape of the transparent deformation member 33E is a circle centered on the center position CL. Further, the distance in the thickness direction between the transparent electrode layer 36E and the transparent electrode layer 37E provided in the central region was set to 0.01 mm. The transparent electrode layers 36E and 37E are made of ITO and are circular thin films having a diameter of 0.8 mm. The filling layer 35E is silicone. For the filling layer 35E, liquid silicone was applied to a desired region on the transparent electrode 42E, the transparent electrode 42E and the transparent deformable member 33E were attached, and then thermally cured at about 130 ° C. to become rubber. In addition, since the initial silicone is liquid, it is possible to easily produce such an extremely thin shape of 0.01 mm.

  FIG. 21 is a characteristic diagram showing the relationship between the applied voltage applied between the transparent electrode layer 36E and the transparent electrode layer 37E and the attractive force generated at that time. In FIG. 21, the horizontal axis is applied voltage (V), and the vertical axis is attractive force (mN) generated between electrode layers. As is apparent from FIG. 21, the attractive force is a value directly proportional to the square of the applied voltage. This attractive force is directly proportional to the cross-sectional area of the transparent electrode layers 36E and 37E and inversely proportional to the square of the distance between the transparent electrode layers 36E and 37E. Therefore, the attractive force can be adjusted by selecting them. is there.

In a general electrostatic actuator, the space between electrodes is filled with air. On the other hand, in this embodiment, the filling layer 35E made of silicone or the like is filled between the transparent electrode layer 36E and the transparent electrode layer 37E. For example, since silicone has a relative dielectric constant of 3 to 10, in this embodiment, when compared with a normal electrostatic actuator, a force of 3 to 10 times can be generated even when the same voltage is applied. Alternatively, a certain attractive force can be generated even at a lower applied voltage. Further, when the gap between the electrodes is filled with the atmosphere, the dielectric breakdown voltage is as low as about 1 kv / mm, so that a very high voltage cannot be applied. Therefore, generally, an electrostatic actuator can obtain a large attractive force. It is not considered. However, when silicone is used as the filling layer 35E as in this embodiment, it has been confirmed that a dielectric breakdown voltage of about 300 kV / mm can be obtained with a distance between electrodes of about 0.01 mm. Therefore, the variable focus lens of the present invention can apply a larger voltage than a normal electrostatic actuator, and can generate an extremely large attractive force. As is clear from FIG. 21, in this example, a large attractive force as much as 20 mN was obtained even at an applied voltage (500 V) lower than the dielectric breakdown voltage.

  The transparent deformable member 33E shown in FIG. 20 has a cross-sectional shape for realizing the ideal aspheric shapes I1 to I3 shown in FIG. The cross-sectional shape is determined by computer simulation using a method such as a finite element method, but it may be actually made and combined. In FIG. 22, the horizontal axis indicates the distance (mm) from the center position CL, and the vertical axis indicates the deformation amount (mm). The ideal aspheric shape I1 corresponds to a case where an attractive force of 10.9 mN is generated between the transparent electrode layers 36E and 37E, and the ideal aspheric shape I2 is a case where an attractive force of 13.4 mN is generated between the transparent electrode layers 36E and 37E. The ideal aspherical shape I3 corresponds to the case where an attractive force of 16.0 mN is generated between the transparent electrode layers 36E and 37E. These ideal aspherical shapes I1 to I3 almost coincided with the calculated values S1 to S3 in the computer simulation by the finite element method.

  Although the present invention has been described with reference to some embodiments and examples, the present invention is not limited to the above-described embodiments and the like, and various modifications are possible. For example, in the above embodiment, an example in which a liquid crystal device is used as a display device has been described. However, the present invention is not limited to this. For example, an organic EL element, a plasma light emitting element, a field emission (FED) element, or a self light emitting element such as a light emitting diode (LED) arranged in an array can be used as a display device. In the case of using such a self-luminous display device, it is not necessary to provide a light source for backlight, so that a simpler configuration can be realized. Although the liquid crystal device described in the above embodiment functions as a transmissive light valve, a reflective light valve such as a GLV (grating light valve) or DMD (digital multi-mirror) is used as a display device. It is also possible. In the above-described embodiment, the example in which the two-dimensional image generating unit, the beam collimating unit, the wavefront converting unit, and the deflecting unit are clearly separated has been described for easy understanding. However, the present invention is not limited to this. is not. In other words, the present invention is not limited to the above-described means that are physically separated, but may conceptually include the above-described means.

  Furthermore, when the wavefront shape of the light from the light source is known (for example, when it is clear that the light wave is a plane wave or a spherical wave), it is not necessary to convert it into a plane wave. For example, as shown in the configuration examples shown in FIGS. 23 to 27 (details will be described later), when a backlight having a high degree of parallelism and extremely close to a plane wave is used, a beam collimating unit (collimator) is used. You don't have to. Further, when the self-luminous element is used and the area of the light-emitting region in each light-emitting pixel is extremely small, the light from the self-luminous element can be regarded as a substantially spherical wave. It is not necessary to use a means (collimating part). When the wavefront shape of light is grasped in this way, a desired wavefront can be formed by controlling wavefront conversion means (variable focus lens, variable focus mirror, etc.) according to the wavefront shape. In addition, it is possible to accurately grasp information regarding binocular parallax, convergence angle, motion parallax, and focal length without using light beam collimating means. Hereinafter, another configuration example of the two-dimensional image generation unit and the beam collimation unit will be described with reference to FIGS.

  In FIG. 23A, the liquid crystal device 11 is used as a means for forming a two-dimensional image, and a lamp 70 such as a halogen lamp, a metal halide lamp, an ultrahigh pressure mercury lamp, or a xenon lamp is used as the light source of the backlight BL. A configuration example (Modification 4) is shown. The lamp 70 includes a light emitting source 71 and a mirror 72. By adjusting the arrangement and shape of the light emission source 71 and the mirror 72, the light emitted from the lamp 70 becomes substantially parallel light. The light emission source 71 is preferably as close to a point light source as possible, and the mirror 72 is preferably parabolic.

  FIG. 23B shows a configuration example (Modification 5) in which the lamp 70 is used as a light source and a deflectable micromirror such as DMD is used as a means for forming a two-dimensional image. The parallel light from the lamp 70 passes through the color wheel 73 and is then reflected and output in a predetermined direction as a two-dimensional image by the micromirror array 74 in which a large number of the deflectable micromirrors are arranged. As shown in FIG. 23C, the color wheel 73 includes a red region 73R, a green region 73G, and a blue region 73B so as to surround the rotation shaft 73Z, and rotates around the rotation shaft 73Z. is there.

  The configuration example (Modification 6) shown in FIG. 24 shows a two-dimensional display unit 81 using a laser light source 65 with high directivity. That is, the two-dimensional display unit 81 has the functions of a two-dimensional image generating unit and a beam collimating unit. In addition to the laser light source 75, a beam expander 76, a micromirror array 74, and a beam expander 77 are disposed in the two-dimensional display unit 81 in order from the side closer to the laser light source 75. Since the light emitted from the laser light source 75 has extremely high directivity, it can be handled as almost parallel light. When the light emitted from the laser light source 75 passes through the beam expander 76, the diameter of the light beam is enlarged so as to have a substantially uniform distribution. Further, a two-dimensional image is formed by the light beam that has passed through the beam expander 76 passing through the micromirror array 74. The two-dimensional image light is further expanded by the beam expander 77 as necessary, and then output from the two-dimensional display unit 81. Instead of the laser light source 75, a highly directional light emitting diode (LED) can be used as the light source.

  The two-dimensional image light output from the two-dimensional display unit 81 is a single color. Therefore, in order to obtain color two-dimensional image light, it is necessary to adopt a configuration (Modification 7) as shown in FIG. FIG. 25 shows a two-dimensional display portion 81R that forms red two-dimensional image light, a two-dimensional display portion 81G that forms green two-dimensional image light, and a two-dimensional display portion 81B that forms blue two-dimensional image light. And a dichroic mirror prism 78. As a result, the two-dimensional image light from each is mixed by the dichroic mirror 78 to obtain a natural two-dimensional image light.

  Furthermore, a two-dimensional image can be formed using a liquid crystal device instead of the micromirror array 64 in the two-dimensional display unit 81 shown in FIG. Specifically, the liquid crystal device 11 and the mirror 79 may be arranged on the optical path as in the two-dimensional display unit 82 shown in FIG. 26 (Modification 8).

  Furthermore, as in the configuration example shown in FIG. 27 (Modification 9), a two-dimensional display unit 82R that forms red two-dimensional image light, a two-dimensional display unit 82G that forms green two-dimensional image light, By combining the two-dimensional display unit 82B that forms blue two-dimensional image light and the dichroic mirror prism 78, color two-dimensional image light can be obtained.

  Alternatively, a DMD type optical deflection element 91 as shown in FIG. 28 may be used as the deflection means (Modification 10). The light deflecting element 91 has a transparent substrate 92 made of a rigid material such as quartz and a movable layer 93, which are arranged so as to face each other, and a filling layer 95 such as silicone filled between them. The movable layer 93 is held by a holding portion 94D that forms a part of the support 94. The surface of the movable layer 93 is covered with a transparent electrode layer 97 so as to face the transparent electrode layers 96A and 96B provided on the surface of the transparent substrate 92, respectively. Further, the holding portion 94D is connected to the support frame 94B via a pair of hinges 94C. The pair of hinges 94 </ b> C has a center axis ω <b> 94 extending along a center line CL that passes through the center position of the movable layer 93. The support frame 94B is disposed on the transparent substrate 92 via a support 94A.

  In the light deflection element 91 having such a configuration, the light beam incident from the transparent substrate 92 side passes through the two openings 94K1 and 94K2 formed by the support frame 94B, the pair of hinges 94C, and the holding portion 94D. Is to be injected. At this time, by applying a voltage between the transparent electrode layer 96A and the transparent electrode layer 97, or between the transparent electrode layer 96B and the transparent electrode layer 97, and rotating the movable layer 93 about the central axis ω94, The incident light beam can be deflected in a predetermined direction.

  Furthermore, as shown in FIG. 29, an optical element 92 having not only a deflection function but also a lens function may be used as the deflection means and the wavefront conversion means (Modification 11). The movable layer 93 is made of a polymer such as a transparent and flexible polyester material, and exhibits a high elastic modulus. Therefore, a desired shape is formed by applying a voltage between the transparent electrode layer 96C and the transparent electrode layer 97, and a condensing or diverging action for the incident light beam is exhibited. Further, by applying a voltage between the transparent electrode layers 96D and 96E and the transparent electrode layer 97, the pair of hinges 94C rotate about the central axis ω94 as an axis to perform a deflection operation.

  In the second embodiment, the reflective deformation member 63 is deformed using the filling layer 65, but the present invention is not limited to this. For example, a piezo element 65A may be provided between the electrode layers 66 and 67 instead of the filling layer 65, like a variable focus mirror 61A as a modification example (modification example 12) shown in FIG. As the piezo element 65A, for example, a thick film made of lead zirconate titanate (PZT) formed by a sol-gel method or the like can be used.

  In each of the above embodiments, the various wavefront conversion means and the deflection means perform the deformation operation using the attractive force of the electrostatic force acting between the electrodes. However, the repulsive force is positively used. It may be. For example, in the varifocal lens 31, the transparent deformable member 33 is formed so as to form a concave shape as shown in FIG. 6B in a state where no electrostatic force is generated between the transparent electrodes 36 and 37, and transparent The state shown in FIG. 6A may be formed by applying a voltage between the electrodes 36 and 37 and charging the same sign to generate a repulsive force.

It is the schematic which shows the structure of the three-dimensional display apparatus as 1st Embodiment in this invention. It is the schematic which shows the structure of the two-dimensional display part and collimating part in the three-dimensional display apparatus shown in FIG. It is the schematic which shows the other structure of the two-dimensional display part and collimating part in the three-dimensional display apparatus shown in FIG. It is the schematic which shows the structure of the lens array in the three-dimensional display apparatus shown in FIG. FIG. 5 is an enlarged plan view and an enlarged sectional view showing a configuration of a variable focus lens in the lens array shown in FIG. 4. It is an expanded sectional view for demonstrating operation | movement of the variable focus lens shown in FIG. FIG. 6 is another enlarged sectional view for explaining the operation of the variable focus lens shown in FIG. 5. FIG. 2 is a plan view and a cross-sectional view showing a configuration of a horizontal deflection unit in the three-dimensional display device shown in FIG. FIG. 7 is another plan view showing the configuration of the horizontal deflection unit in the three-dimensional display device shown in FIG. 1. It is an expanded sectional view for demonstrating operation | movement of the optical deflection | deviation element in the horizontal direction deflection | deviation part shown in FIG. It is sectional drawing for demonstrating the whole operation | movement of the optical deflection | deviation element in the horizontal direction deflection | deviation part shown in FIG. FIG. 2 is a plan view for explaining an arrangement relationship between a horizontal direction deflection unit and a vertical direction deflection unit in the three-dimensional display device shown in FIG. 1. It is a conceptual diagram for demonstrating the operation | movement at the time of observing a stereo image in the three-dimensional display apparatus shown in FIG. FIG. 7 is another conceptual diagram for explaining an operation when observing a stereoscopic image in the three-dimensional display device shown in FIG. 1. FIG. 6 is a plan view and a cross-sectional view illustrating a configuration of a variable focus lens in the three-dimensional display device illustrated in FIG. 1 as a first modified example (modified example 1). FIG. 10 is a plan view and a cross-sectional view illustrating a configuration of a variable focus lens as a second modification (Modification 2) of the three-dimensional display device illustrated in FIG. 1. FIG. 10 is a plan view and a cross-sectional view illustrating a configuration of a variable focus lens as a third modified example (modified example 3) in the three-dimensional display device illustrated in FIG. 1. It is the schematic which shows the structure of the three-dimensional display apparatus as 2nd Embodiment in this invention. It is the schematic which shows the structure of the mirror array in the three-dimensional display apparatus shown in FIG. It is sectional drawing which showed the structure of the variable focus lens as an Example of this invention. It is a characteristic view showing the relationship between the applied voltage and the attractive force which generate | occur | produces between electrode layers in a present Example. It is a characteristic view showing the relationship between the attractive force and the amount of deformation in the present embodiment. It is the schematic which showed the modification (modifications 4 and 5) in the two-dimensional image generation means and light beam collimation means of this invention. It is the schematic which showed the modification (modification 6) in the two-dimensional image generation means and light beam collimation means of this invention. It is the schematic which showed the modification (modification 7) in the two-dimensional image generation means and light beam collimation means of this invention. It is the schematic which showed the modification (modification 8) in the two-dimensional image generation means and light beam collimation means of this invention. It is the schematic which showed the modification (modification 9) in the two-dimensional image generation means and light beam collimation means of this invention. It is the schematic which showed the optical deflection | deviation element as a modification (modification 10) in the deflection | deviation means of this invention. It is the schematic which showed the optical element as a modification (modification 11) in the deflection | deviation means and wavefront conversion means of this invention. FIG. 20 is a schematic diagram showing a modification (Modification 12) of the mirror array shown in FIG. 19.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Two-dimensional display part, 10 ... Three-dimensional display apparatus, 11 ... Liquid crystal device, 12 ... Glass substrate, 13 ... Pixel electrode, 14 ... Glass substrate, 2 ... Collimating part, 21 ... Micro lens, 3 ... Lens array, 31 DESCRIPTION OF SYMBOLS ... Variable focus lens, 32 ... Transparent substrate, 33 ... Transparent deformation member, 34 ... Support | pillar, 35 ... Filling layer, 36, 37 ... Transparent electrode layer, 38 ... External control power supply, 39 ... Communication hole, 4 ... Horizontal direction deflection part 4B ... Galvano mirror, 41 ... Optical deflection element, 42 ... Transparent substrate, 43 ... Movable layer, 44 ... Support, 45 ... Filling layer, 46, 47A, 47B ... Transparent electrode layer pattern, 5 ... Vertical deflection unit, 6 ... Mirror array, 61 ... Variable focus mirror, 62 ... Substrate, 63 ... Reflective deformation member, 64 ... Strut, 65 ... Filling layer, 65A ... Piezo element, 66, 67 ... Electrode layer, 68 ... External control power supply, 69 ... communication hole.

Claims (11)

A rigid layer made of a transparent material;
An elastic layer made of a transparent material disposed opposite the rigid layer;
A filling layer made of a transparent material, filled between the rigid layer and the elastic layer;
A transparent electrode layer pair provided on one surface of the rigid layer and one surface of the elastic layer,
The elastic layer has an elastic constant distribution in a direction along the layer surface. The variable focus lens according to claim 1, wherein the elastic constant distribution in the elastic layer is defined by its own thickness distribution. The variable focus lens according to claim 2, wherein the thickness of the elastic layer is gradually reduced from the central portion toward the peripheral portion. The variable focus lens according to claim 2, wherein the thickness of the elastic layer gradually increases from the central portion toward the peripheral portion. The variable focus lens according to claim 1, wherein the elastic layer and the filling layer have the same refractive index for a predetermined light wavelength. The variable focus lens according to claim 1, wherein the filling layer is made of a fluid material. The flowable material constituting the filling layer is filled only in a part of the region sandwiched between the rigid layer and the elastic layer, including at least a light transmission region, and the other region is in the external space. The variable focus lens according to claim 6, wherein the variable focus lens is secured as a buffer region having a communication hole to be connected. A rigid layer;
An elastic layer disposed opposite the rigid layer;
A filling layer filled between the rigid layer and the elastic layer;
A reflective layer provided on a surface of the elastic layer opposite to the rigid layer;
An electrode layer pair provided on one surface of the rigid layer and one surface of the elastic layer,
The elastic layer has an elastic constant distribution in a direction along the layer surface. The variable focus mirror according to claim 8, wherein the elastic constant distribution in the elastic layer is defined by its own thickness distribution. The variable focus mirror according to claim 9, wherein the thickness of the elastic layer is gradually reduced from the central portion toward the peripheral portion. The variable focus mirror according to claim 9, wherein the thickness of the elastic layer is gradually increased from the central portion toward the peripheral portion.

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