JP2016090759A - Liquid crystal lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress condensation misalignment of a liquid crystal lens as much as possible and to significantly enhance coupling performance.SOLUTION: A liquid crystal lens includes, successively from one side on an optical axis C, a first liquid crystal layer 2a, a second liquid crystal layer 2b, a third liquid crystal layer 2c and a fourth liquid crystal layer 2d, in which in a plane perpendicular to the optical axis C, alignment directions of the first liquid crystal layer 2a and the second liquid crystal layer 2b differ by 90°, alignment directions of the first liquid crystal layer 2a and the fourth liquid crystal layer 2d differ by 180°, and alignment directions of the second liquid crystal layer 2b and the third liquid crystal layer 2c differ by 180°. The liquid crystal lens also includes: a first electrode 13 and a second electrode 14 of different types, which interpose the first liquid crystal layer 2a and the second liquid crystal layer 2b and apply a voltage to both the liquid crystal layers; and a third electrode 15 and a fourth electrode 16 of different types, which interpose the third liquid crystal layer 2c and the fourth liquid crystal layer 2d and apply a voltage to both the liquid crystal layers. The second electrode 14 and the third electrode 15 are formed on opposite surfaces of a planar body 5 present between the second liquid crystal layer 2b and the third liquid crystal layer 2c, and the electrodes 14, 15 are electrodes of the same type.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquid crystal lens, and more particularly to a technique for improving the light condensing property of a liquid crystal lens having four liquid crystal layers.

  As is well known, a liquid crystal lens forms a liquid crystal layer by enclosing a liquid crystal in a layered space and the like, and a voltage is applied by different types of electrodes, ie, a power electrode and a ground electrode that sandwich the liquid crystal layer. It is configured so that the lens function can be exhibited by controlling the molecular orientation.

  This type of liquid crystal lens can be adapted to natural light without the need for a polarizing plate when there are two liquid crystal layers. However, in this natural light compatible liquid crystal lens, the influence of the tilt angle of the liquid crystal molecules As a result, the optical axis center shifts, so that the light condensing performance is deteriorated and sufficient coupling performance cannot be obtained.

  In order to cope with such a problem, in Patent Document 1, first to fourth liquid crystal layers are arranged in order from one side on the optical axis, and the first and second liquid crystal layers are arranged in a plane perpendicular to the optical axis. The orientation directions of the liquid crystal layers are different from each other by 90 °, the orientation directions of the first and fourth liquid crystal layers are different from each other by 180 °, and each of the second and third liquid crystal layers is different. A liquid crystal lens is disclosed that is configured with the orientation directions different from each other by 180 °.

  According to this liquid crystal lens, on both sides of the center of the optical axis direction of the entire lens, a liquid crystal layer having a liquid crystal molecule alignment direction parallel to P-polarized light (hereinafter referred to as a P-polarized liquid crystal layer) and S-polarized light The liquid crystal layers (hereinafter referred to as “S-polarized liquid crystal layers”) having parallel alignment directions of liquid crystal molecules are arranged symmetrically. Therefore, it can be expected that the difference in the focal position between the incident light of P-polarized light and the incident light of S-polarized light is reduced to suppress the deviation of the condensing position.

JP 2013-156423 A

  However, as a result of intensive studies by the present inventors, even with the liquid crystal lens disclosed in Patent Document 1, the present invention has sufficient characteristics from the viewpoint of condensing deviation between P-polarized light and S-polarized light. Since it came to know that there is no, there still remains a problem to be solved.

  That is, in the liquid crystal lens shown in FIG. 1 of Patent Document 1, a P-polarization liquid crystal layer is arranged on each of the upper end and the lower end, and two S-polarizations are arranged on the inner side in the vertical direction of these two P-polarization liquid crystal layers. The power supply electrode is arranged above the upper P-polarization liquid crystal layer, and the ground electrode is arranged below the lower P-polarization liquid crystal layer.

  More specifically, this liquid crystal lens is arranged so that the P-polarization liquid crystal layer and the S-polarization liquid crystal layer are symmetrical on both sides of the center of the optical axis direction of the entire lens. In any case, the distances to the two P-polarization liquid crystal layers are different, and the distances to the two S-polarization liquid crystal layers are also different.

  Further, in the liquid crystal lens shown in FIG. 4 of Patent Document 1, the arrangement order of the two P-polarization liquid crystal layers and the two S-polarization liquid crystal layers is the same as that of the liquid crystal lens described above. The arrangement of the upper and lower electrodes is the same. However, in this liquid crystal lens, a substrate is interposed between two liquid crystal layers for S polarization, a ground electrode is formed on the upper surface portion of the substrate, and a power supply electrode is formed on the lower surface portion thereof.

  Accordingly, this liquid crystal lens is also arranged so that the P-polarization liquid crystal layer and the S-polarization liquid crystal layer are symmetrical on both sides of the center in the optical axis direction of the entire lens. However, the distances to the two P-polarization liquid crystal layers are different, and the distances to the two S-polarization liquid crystal layers are also different.

  Both of the above two liquid crystal lenses have different distances to the ground electrode and the power supply electrode for the two P-polarization liquid crystal layers, and to the ground electrode and the power supply electrode for the two S-polarization liquid crystal layers. Since the distances are different, the refractive index distribution of the P-polarized liquid crystal layer and the refractive index distribution of the S-polarized liquid crystal layer do not exactly match. For this reason, the focal length (synthetic focal length) for the incident light of P-polarized light, that is, the focal position, and the focal length (synthetic focal distance) for the incident light of S-polarized light, and hence the focal position are not the same. Will still remain.

  From the above viewpoints, an object of the present invention is to suppress the condensing deviation of the liquid crystal lens as much as possible and to greatly improve the coupling performance.

  The present invention, which was created to solve the above problems, has a first liquid crystal layer, a second liquid crystal layer, a third liquid crystal layer, and a fourth liquid crystal layer in order from one side on the optical axis, Within the plane perpendicular to the optical axis, the alignment directions of the first liquid crystal layer and the second liquid crystal layer differ by 90 °, and the alignment directions of the first liquid crystal layer and the fourth liquid crystal layer differ by 180 °. The second liquid crystal layer and the third liquid crystal layer have different orientation directions by 180 °, and the first liquid crystal layer and the second liquid crystal layer are sandwiched and a voltage is applied to both the liquid crystal layers. A first electrode and a second electrode; and a third liquid crystal layer and a fourth electrode of different types for sandwiching the third liquid crystal layer and the fourth liquid crystal layer and applying a voltage to both liquid crystal layers, the second liquid crystal layer And the third electrode are formed on opposite surfaces of a plate-like body interposed between the second liquid crystal layer and the third liquid crystal layer. Characterized in that the two electrodes is an electrode of the same kind. Here, “different” of the two electrodes means that one electrode is a power supply electrode and the other electrode is a ground electrode. Further, “the same kind” of the two electrodes means a case where both electrodes are power supply electrodes or a case where both electrodes are ground electrodes.

  According to such a configuration, the liquid crystal layer for P-polarization and the liquid crystal layer for S-polarization are arranged symmetrically on both sides of the center of the optical axis of the entire lens, in addition to the ground electrode and the power source. From any of the electrodes, the distance to the two P-polarized liquid crystal layers can be made the same, and the distance to the two S-polarized liquid crystal layers can be made the same. As described above, if the two P-polarized liquid crystal layers have the same distance to the ground electrode and the power supply electrode, and the two S-polarized liquid crystal layers have the same distance to the ground electrode and the power supply electrode, the P-polarization liquid crystal layer can be used. It becomes possible to match the refractive index distribution of the liquid crystal layer and the refractive index distribution of the liquid crystal layer for S-polarization very accurately. As a result, the focal length (synthetic focal length) for the incident light of P-polarized light, that is, the focal position, and the focal length (synthetic focal length) for the incident light of S-polarized light, and hence the focal position can be the same. The problem of light misalignment is avoided as much as possible, and the coupling performance is greatly improved.

  In such a configuration, the second electrode and the third electrode are preferably power supply electrodes.

  As described above, when the second electrode and the third electrode are used as the power supply electrodes, the electrodes can be easily aligned and the liquid crystal lens is prevented from being misaligned as compared with the case where the first electrode and the fourth electrode are used as the power supply electrodes. it can.

  In the above configuration, the plate-like body is preferably a single substrate.

  In this way, as in the case where the plate-like body is constituted by two substrates (for example, two glass substrates), there is a possibility that a positional deviation occurs at the time of bonding and an error occurs in an inherent lens function. In addition, the thickness can be reduced to make the transmittance appropriate, and the number of parts can be reduced.

  In the above configuration, it is preferable that the thickness of each of the first liquid crystal layer and the fourth liquid crystal layer is larger than the thickness of each of the second liquid crystal layer and the third liquid crystal layer.

  In this case, if the thicknesses of the first to fourth liquid crystal layers are all the same, light is incident only from one side, so that the light is collected between both the P-polarization liquid crystal layer and the S-polarization liquid crystal layer. There is a possibility that the optical action shifts and the combined focal length for the P-polarized incident light and the combined focal length for the S-polarized incident light become non-uniform. However, as described above, by changing the thicknesses of the P-polarized liquid crystal layer and the S-polarized liquid crystal layer, the combined focal length for the P-polarized incident light and the combined focal length for the S-polarized incident light can be efficiently obtained. It can be made equal.

  As described above, according to the present invention, it is possible to significantly improve the coupling performance by preventing the liquid crystal lens from condensing as much as possible.

1 is a longitudinal front view illustrating an overall schematic configuration of a liquid crystal lens according to a first embodiment of the present invention. It is a top view which shows the principal part schematic structure of the power supply electrode which is a component of the liquid crystal lens which concerns on 1st Embodiment of this invention. It is a vertical front view which shows the principal part schematic structure of the liquid crystal lens which concerns on 1st Embodiment of this invention. It is a vertical front view which shows the principal part schematic structure of the liquid crystal lens which concerns on 2nd Embodiment of this invention. It is a vertical front view which shows the principal part schematic structure of the liquid crystal lens which concerns on 3rd Embodiment of this invention.

  Hereinafter, a liquid crystal lens according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic longitudinal sectional front view showing the entire configuration of the liquid crystal lens 1 according to the first embodiment of the present invention. As shown in the figure, the liquid crystal lens 1 includes four liquid crystal layers 2a, 2b, 2c, and 2d containing liquid crystal molecules, and in detail, sequentially from one side in the optical axis C direction (upper side in the illustrated example). The first liquid crystal layer 2a, the second liquid crystal layer 2b, the third liquid crystal layer 2c, and the fourth liquid crystal layer 2d are arranged in parallel to each other.

  The liquid crystal enclosure 3 in which the first to fourth liquid crystal layers 2a, 2b, 2c, and 2d are formed has an end (upper end) on one side and an end (lower end) in the optical axis C direction. Part) is a drum body having a cubic shape or a rectangular parallelepiped shape, and its internal space is partitioned into four liquid crystal layers 2a, 2b, 2c, and 2d that enclose liquid crystals. Yes. Specifically, the liquid crystal enclosure 3 includes an upper end substrate 4 disposed at the upper end, a central substrate 5 disposed at the center in the vertical direction, a lower end substrate 6 disposed at the lower end, the upper end substrate 4 and the central substrate 5. The upper intermediate substrate 7 disposed between the lower substrate 6 and the lower intermediate substrate 8 disposed between the central substrate 5 and the lower substrate 6. Each of these substrates 4, 5, 6, 7, 8 is a transparent glass plate having a rectangular flat plate shape, and the thicknesses of the upper substrate 4, the central substrate 5, and the lower substrate 6 are 0.1 to 1 for example. The thickness of the upper intermediate substrate 7 and the lower intermediate substrate 8 is, for example, 0.003 to 0.08 mm, and the thickness of the former substrates 4, 5, and 6 is the latter intermediate substrate 7, The plate thickness is 8 times or more. Further, cylindrical members 9, 10, 11, and 12 whose optical axis C and the center axis coincide with each other are interposed between the outer peripheral edges of these substrates 4, 5, 6, 7, and 8. The cylindrical members 9, 10, 11, and 12 each have a cross-sectional shape orthogonal to the optical axis C, and the outer peripheral contour forms a rectangle and the inner peripheral contour forms a circle. These cylindrical members 9, 10, 11, and 12 are also formed of transparent glass, and the plate thickness is, for example, 0.004 to 0.08 mm.

  Therefore, the first liquid crystal layer 2 a is formed by sealing liquid crystal in a substantially cylindrical space defined by the upper end substrate 4, the upper intermediate substrate 7, and the cylindrical member 9. In the same manner, the second liquid crystal layer 2b is formed from the upper intermediate substrate 7, the central substrate 5, and the cylindrical member 10, and the third liquid crystal is formed from the central substrate 5, the lower intermediate substrate 8, and the cylindrical member 11. The layer 2c is formed, and the fourth liquid crystal layer 2d is formed from the lower intermediate substrate 8, the lower end substrate 6, and the cylindrical member 12. The alignment direction in the first liquid crystal layer 2a and the alignment direction in the second liquid crystal layer 2b are different by 90 ° in a plane perpendicular to the optical axis C. Further, the alignment direction in the first liquid crystal layer 2a and the alignment direction in the fourth liquid crystal layer 2d are different from each other by 180 ° in a plane perpendicular to the optical axis C. Further, the alignment direction in the second liquid crystal layer 2b and the alignment direction in the third liquid crystal layer 2c are different by 180 ° in a plane perpendicular to the optical axis C. In this embodiment, since the first liquid crystal layer 2a and the fourth liquid crystal layer 2d have the alignment direction of liquid crystal molecules parallel to the incident light of P-polarized light, the liquid crystal layer for P-polarization is used. Since the liquid crystal layer 2b and the third liquid crystal layer 2c have the alignment direction of the liquid crystal molecules parallel to the S-polarized incident light, the liquid crystal layer is an S-polarized liquid crystal layer.

  However, the upper power supply electrode 13 as the first electrode is formed on the lower surface portion of the upper substrate 4, and the upper ground electrode 14 as the second electrode is formed on the upper surface portion of the central substrate 5. Further, a lower ground electrode 15 as a third electrode is formed on the lower surface portion of the central substrate 5, and a lower power supply electrode 16 as a fourth electrode is formed on the upper surface portion of the lower substrate 6. . Therefore, in the liquid crystal lens 1, a voltage is applied to the first liquid crystal layer 2a and the second liquid crystal layer 2b by the upper power supply electrode 13 and the upper ground electrode 14, and the lower power supply electrode 16 and the lower ground electrode are applied. A voltage is applied to the third liquid crystal layer 2c and the fourth liquid crystal layer 2d by the electrode 15. In this case, as shown in FIG. 2, each of the upper power supply electrode 13 and the lower power supply electrode 16 has a circular central portion 13a (16a) and an enclosing portion 13b (16b) surrounding the central portion 13a (16a). The outer peripheral end surface of the surrounding portion 13b (16b) and the inner peripheral surface of the tubular member 9 (12) are in contact or substantially in contact with each other over the entire circumference. On the other hand, although not shown, each of the upper ground electrode 14 and the lower ground electrode 15 has a single circular flat plate shape, and the outer peripheral end surfaces thereof and the inner peripheral surfaces of the cylindrical members 10 and 11 are in contact with each other or substantially. In contact. These electrodes 13, 14, 15, and 16 can be formed of a transparent conductive oxide such as indium tin oxide (ITO). In particular, when formed of indium tin oxide, visible light The transmittance in the region is increased and the conductivity is also increased.

  Although not shown, an insulating film is formed on the lower surface portion of the upper substrate 4 and the upper surface portion of the lower substrate 6 so as to cover the upper power supply electrode 13 and the lower power supply electrode 16, respectively. In this way, high resistance films are formed, an insulating film is formed so as to cover these high resistance films, and an alignment film is further formed so as to cover the insulating film. An alignment film is formed on the upper surface portion and the lower surface portion of the central substrate 5 so as to cover the upper ground electrode 14 and the lower ground electrode 15. Further, alignment films are formed on the upper surface portion and the lower surface portion of the upper intermediate substrate 7, respectively, and alignment films are also formed on the upper surface portion and the lower surface portion of the lower intermediate substrate 8, respectively. Accordingly, the first to fourth liquid crystal layers 2a, 2b, 2c, and 2d are in a state where all of the layers are sandwiched between a pair of alignment films, whereby the alignment of the liquid crystal molecules in each liquid crystal layer is performed. Thus, the P-polarized liquid crystal layer and the S-polarized liquid crystal layer are formed separately. The high resistance film is for lowering the driving voltage of the liquid crystal lens 1, and the insulating layer is for insulating the electrode and the high resistance film. Note that the insulating layer and the high resistance film may be omitted as appropriate.

  As shown in FIG. 3, the liquid crystal lens 1 according to the present embodiment has a P-polarized liquid crystal layer (first liquid crystal layer 2a and fourth liquid crystal layer 2d) on both sides of the center X in the optical axis direction (vertical direction). The liquid crystal layers for S polarization (second liquid crystal layer 2b and third liquid crystal layer 2c) are arranged symmetrically. The distance L1 from the upper ground electrode 14 to the vertical center of the first liquid crystal layer 2a is made equal to the distance L2 from the lower ground electrode 15 to the vertical center of the fourth liquid crystal layer 2d, and the upper ground The distance L3 from the electrode 14 to the center in the up-down direction of the second liquid crystal layer 2b is made equal to the distance L4 from the lower ground electrode 15 to the center in the up-down direction of the third liquid crystal layer 2c. Further, the distance L5 from the upper power supply electrode 13 to the vertical center of the first liquid crystal layer 2a and the distance L6 from the lower power supply electrode 16 to the vertical center of the fourth liquid crystal layer 2d are made equal, and the upper power supply The distance L7 from the electrode 13 to the vertical center of the second liquid crystal layer 2b and the distance L8 from the lower power supply electrode 16 to the vertical center of the third liquid crystal layer 2c are made equal. That is, for the two P-polarization liquid crystal layers 2a and 2d, the distances from the ground electrodes 14 and 15 and the power supply electrodes 13 and 16 are equal to each other, and the two S-polarization liquid crystal layers 2b and 2c are also ground electrodes. 14 and 15 and the power supply electrodes 13 and 16 are made equal to each other.

  Furthermore, in the liquid crystal lens 1 according to the present embodiment, the thickness (length in the optical axis direction) T1 of the first liquid crystal layer (P-polarization liquid crystal layer) 2a and the thickness T2 of the fourth liquid crystal layer (P-polarization liquid crystal layer) 2d. And the thickness T3 of the second liquid crystal layer (S-polarization liquid crystal layer) 2b and the thickness T4 of the third liquid crystal layer (S-polarization liquid crystal layer) 2c are the same. On the other hand, the thicknesses T1 and T2 of the first liquid crystal layer 2a and the fourth liquid crystal layer 2d are both larger than the thicknesses T3 and T4 of the second liquid crystal layer 2b and the third liquid crystal layer 2c. Specifically, the difference between the thicknesses T1 and T2 of the first and fourth liquid crystal layers 2a and 2d and the thicknesses T3 and T4 of the second and third liquid crystal layers 2b and 2c is 0 of the latter thicknesses T3 and T4. About 0.001 to 1%. The difference in thickness is based on the basic concept that all the thicknesses T1, T2, T3, and T4 of the first to fourth liquid crystal layers 2a, 2b, 2c, and 2d are equal or substantially equal. It is preferable to provide it.

  According to the liquid crystal lens 1 having the above-described configuration, the first liquid crystal layer 2a and the fourth liquid crystal layer 2d are different in the orientation direction by 180 °, and thus are perpendicular to the optical axis C of the first liquid crystal layer 2a. The deviation of the focal position in the plane and the deviation of the focal position in the plane perpendicular to the optical axis C by the fourth liquid crystal layer 2d cancel each other. Therefore, it is possible to reduce the amount of deviation between the optical axis C and the focal position of the liquid crystal lens 1 as a whole in the plane perpendicular to the optical axis C with respect to the P-polarized incident light. Similarly, the second liquid crystal layer 2b and the third liquid crystal layer 2c are also different in the orientation direction by 180 °, so that the shift of the focal position in the plane perpendicular to the optical axis C by the second liquid crystal layer 2b The deviation of the focal position in the plane perpendicular to the optical axis C by the three liquid crystal layers 2c cancels each other. Therefore, it is possible to reduce the amount of deviation between the optical axis C and the focal position of the liquid crystal lens 1 as a whole in a plane perpendicular to the optical axis C with respect to the incident light of S-polarized light.

  The first liquid crystal layer 2a and the fourth liquid crystal layer 2d, which are P-polarized liquid crystal layers, are arranged at one end and the other end in the direction along the optical axis C. Since the second liquid crystal layer 2b and the third liquid crystal layer 2c, which are liquid crystal layers for S polarization, are arranged between the layer 2a and the fourth liquid crystal layer 2d, the lens center for the incident light of P polarization and the S Both the center of the lens with respect to the polarized incident light coincide with each other at the center X of the liquid crystal lens 1 in the direction of the optical axis C. Therefore, the difference between the focal position of the P-polarized incident light and the focal position of the S-polarized incident light can be reduced.

  Further, the first liquid crystal layer 2a and the fourth liquid crystal layer 2d, which are P-polarized liquid crystal layers, have the same distance from the ground electrodes 14 and 15 and the power supply electrodes 13 and 16, and are the second liquid crystal layers for S-polarized light. Since the liquid crystal layer 2b and the third liquid crystal layer 2c are also equal in distance from the ground electrodes 14 and 15 and the power supply electrodes 13 and 16, the refractive index distribution in the P-polarization liquid crystal layer and the refraction in the S-polarization liquid crystal layer. The rate distribution can be matched very accurately. Therefore, it is possible to make the focal length (combined focal length) for the incident light of P-polarized light and the focal position coincide with the focal length (composite focal length) for the incident light of S-polarized light and the focal position.

  Also, the second liquid crystal layer is disposed such that the thicknesses T1 and T2 of the first liquid crystal layer 2a and the fourth liquid crystal layer 2d disposed away from the center X in the optical axis C direction of the liquid crystal lens 1 are close to the center X. Even when the thicknesses T3 and T4 of 2b and the third liquid crystal layer 2c are made larger, the focal length (synthetic focal length) for P-polarized incident light and the focal length (synthetic focal length) for S-polarized incident light are set. It plays the role of equality. That is, if the thicknesses of the first to fourth liquid crystal layers 2a, 2b, 2c, and 2d are all the same, the light is transmitted to one side even though the liquid crystal layers have a difference in distance from the center X. Therefore, the light condensing action shifts between the P-polarized liquid crystal layer and the S-polarized liquid crystal layer. Therefore, there is a possibility that the combined focal length for the P-polarized incident light and the combined focal length for the S-polarized incident light are not uniform. However, as described above, by changing the thicknesses of the P-polarized liquid crystal layer and the S-polarized liquid crystal layer, the combined focal length for the P-polarized incident light and the combined focal length for the S-polarized incident light can be efficiently obtained. It can be made equal.

  FIG. 4 is a longitudinal front view showing a schematic configuration of the main part of the liquid crystal lens 1 according to the second embodiment of the present invention. As shown in the figure, the liquid crystal lens 1 according to the second embodiment is different from that according to the first embodiment described above in that the first is arranged in order from one side in the optical axis C direction. The liquid crystal layer 2a, the second liquid crystal layer 2b, the third liquid crystal layer 2c, and the fourth liquid crystal layer 2d are respectively an S-polarization liquid crystal layer, a P-polarization liquid crystal layer, a P-polarization liquid crystal layer, and an S-polarization liquid crystal layer. Is where you are. That is, two P-polarized liquid crystal layers are interposed between the two S-polarized liquid crystal layers arranged away from the vertical center X. Further, when the thicknesses of the liquid crystal layers 2a, 2b, 2c, and 2d are changed, the two S-polarized liquid crystal layers are made thicker than the two P-polarized liquid crystal layers. Since other configurations are the same as those in the first embodiment described above, common configuration requirements are denoted by the same reference numerals, and description thereof is omitted. The liquid crystal lens 1 according to the second embodiment can enjoy the same functions and effects as those of the liquid crystal lens 1 according to the first embodiment.

  FIG. 5 is a longitudinal front view showing a schematic configuration of the main part of the liquid crystal lens 1 according to the third embodiment of the present invention. As shown in the figure, the liquid crystal lens 1 according to the third embodiment differs from that according to the first embodiment described above in the lower surface portion of the upper end substrate 4 and the upper surface portion of the lower end substrate 6. The ground electrodes 14 and 15 are formed, and the power supply electrodes 13 and 16 are formed on the upper surface portion and the lower surface portion of the central substrate 5. Even in this configuration, the distances from the ground electrodes 14 and 15 and the power supply electrodes 13 and 16 are equal to each other for the two P-polarized liquid crystal layers, and the ground is also applied to the two S-polarized liquid crystal layers. The distances from the electrodes 14 and 15 and the power supply electrodes 13 and 16 are equal to each other. Since other configurations are the same as those in the first embodiment described above, common configuration requirements are denoted by the same reference numerals, and description thereof is omitted. The liquid crystal lens 1 according to the third embodiment can enjoy the same functions and effects as those of the liquid crystal lens 1 according to the first embodiment. In the liquid crystal lens 1 according to the third embodiment, the arrangement order of the P-polarization liquid crystal layer and the S-polarization liquid crystal layer may be the same as that of the liquid crystal lens 1 according to the second embodiment.

  In the first to third embodiments described above, the central substrate 5 of the liquid crystal enclosure 3 is formed of a single substrate. The central substrate 5 includes the first liquid crystal layer 2a and the second liquid crystal layer 2b. And a lower substrate of a liquid crystal encapsulant for forming two liquid crystal layers and an upper substrate of a liquid crystal encapsulant for forming two liquid crystal layers of the third liquid crystal layer 2c and the fourth liquid crystal layer 2d. It may be configured to be attached. However, when the intermediate substrate 5 is composed of a single substrate, there is no possibility that an error occurs in the lens function that should be inherent due to a positional deviation at the time of bonding, and the thickness is reduced and the transmittance is appropriately adjusted. In addition, there is an advantage that the number of parts can be reduced.

  Furthermore, in the above first to third embodiments, all of the components of the liquid crystal enclosure 3 are the upper substrate 4, the intermediate substrate 5, the lower substrate 6, the upper intermediate substrate 7, the lower intermediate substrate 8, and the cylinder. Although the shape members 9, 10, 11, and 12 are formed of transparent glass, all or part of them may be formed of ceramic, aluminum, or resin.

DESCRIPTION OF SYMBOLS 1 Liquid crystal lens 2a 1st liquid-crystal layer 2b 2nd liquid-crystal layer 2c 3rd liquid-crystal layer 2d 4th liquid-crystal layer 4 Upper end board | substrate 5 Central board | substrate (plate-shaped object)
6 Lower substrate 13 Upper power supply electrode 14 Upper ground electrode 15 Lower ground electrode 16 Lower power supply electrode C Optical axis T1 First liquid crystal layer thickness T2 Second liquid crystal layer thickness T3 Third liquid crystal layer thickness T4 Fourth liquid crystal layer Thickness

Claims (4)

In order from one side on the optical axis, it has a first liquid crystal layer, a second liquid crystal layer, a third liquid crystal layer, and a fourth liquid crystal layer,
Within the plane perpendicular to the optical axis, the alignment directions of the first liquid crystal layer and the second liquid crystal layer differ by 90 °, and the alignment directions of the first liquid crystal layer and the fourth liquid crystal layer differ by 180 °. The orientation directions of the second liquid crystal layer and the third liquid crystal layer are different by 180 °,
The first liquid crystal layer and the second liquid crystal layer are sandwiched, and different types of first and second electrodes for applying a voltage to the two liquid crystal layers are sandwiched, and the third liquid crystal layer and the fourth liquid crystal layer are sandwiched. A third electrode and a fourth electrode of different types for applying a voltage to both liquid crystal layers;
The second electrode and the three electrodes are formed on opposite surfaces of a plate-like body interposed between the second liquid crystal layer and the third liquid crystal layer, and both electrodes are the same kind of electrodes. LCD lens.   The liquid crystal lens according to claim 1, wherein the second electrode and the third electrode are power supply electrodes.   The liquid crystal lens according to claim 1, wherein the plate-like body is a single substrate.   4. The liquid crystal according to claim 1, wherein each thickness of the first liquid crystal layer and the fourth liquid crystal layer is larger than each thickness of the second liquid crystal layer and the third liquid crystal layer. lens.

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