Eyeglasses and optical elements

Abstract

To provide spectacles that can shorten a time from start to completion of the control of refraction of light as compared with a mechanical control mechanism.SOLUTION: Spectacles 1 control light incident on eyes. The spectacles 1 include optical elements LN and a control unit 17. The optical elements LN include a liquid crystal layer 53 that refracts light. The control unit 17 applies control voltage to the liquid crystal layer 53 to form a serrated potential gradient in the liquid crystal layer 53, and controls refraction of light. The spectacles 1 may further include an eye detection unit 75 that detects movement of an eye. The control unit 17 controls the control voltage based on a detection result of the eye detection unit 75.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to eyeglasses and optical elements. [Background technology]

[0002] The glasses described in Patent Document 1 detect the gaze direction and adjust the focus. Specifically, the glasses include a gaze direction detector and a variable-focus lens that can change the focal length. The glasses adjust the focus of the variable-focus lens based on a gaze direction signal from the gaze direction detector.

[0003] The variable-focus lens has a mechanical focus adjustment mechanism. Specifically, the variable-focus lens includes two transparent plate-like objects, a transparent body, and an actuator. The transparent body is a deformable fluid having a refractive index different from that of air. The transparent body is interposed between the two plate-like objects so as to fill the space between them. The actuator changes the shapes of the two plate-like objects and the transparent body. As a result, the refraction state of the light passing through the two plate-like objects changes, and the focus is adjusted. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2000-249902 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the glasses described in Patent Document 1, the focus is adjusted by a mechanical focus adjustment mechanism, so it is difficult to shorten the time from the start to the completion of control for focus adjustment.

[0006] In other words, it is difficult to shorten the time from the start to the completion of control of the refraction of light with a mechanical control mechanism.

[0007] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide glasses that can shorten the time from the start to the completion of control of light refraction, compared to mechanical control mechanisms. [Means for solving the problem]

[0008] According to one aspect of the present invention, a pair of glasses controls light incident on an eye. The pair of glasses includes an optical element and a controller. The optical element includes a liquid crystal layer that refracts light. The controller applies a control voltage to the liquid crystal layer to form a sawtooth potential gradient in the liquid crystal layer and control the refraction of light.

[0009] The eyeglasses according to the present invention preferably further include an eye detection unit that detects eye movement. The control unit preferably controls the control voltage based on a detection result of the eye detection unit.

[0010] In the eyeglasses of the present invention, it is preferable that the optical element further includes a light transmitting layer capable of controlling the light transmittance.

[0011] The eyeglasses of the present invention preferably further include a pressure detection unit that detects pressure.

[0012] The eyeglasses of the present invention preferably further include a notification unit which notifies the user of the location of the eyeglasses in response to a predetermined signal transmitted wirelessly.

[0013] In the eyeglasses of the present invention, it is preferable that the optical element further includes an optical member having a sawtooth cross section that deflects light. Effect of the Invention

[0014] According to the present invention, the time from start to completion of control of light refraction can be reduced as compared to a mechanical control mechanism. [Brief description of the drawings]

[0015] [Figure 1] 1 is a perspective view showing an eyeglass system according to a first embodiment of the present invention. [Diagram 2] 2 is a schematic cross-sectional view of the optical element taken along line II-II in FIG. [Diagram 3] (a) is a diagram showing the potential gradient of the liquid crystal layer when the optical element according to embodiment 1 functions as a convex lens, (b) is a diagram showing the focal length when the optical element according to embodiment 1 functions as a convex lens, (c) is a diagram showing the potential gradient of the liquid crystal layer when the optical element according to embodiment 1 functions as a concave lens, and (d) is a diagram showing the focal length when the optical element according to embodiment 1 functions as a concave lens. [Figure 4] FIG. 2 is a plan view showing a first liquid crystal unit according to the first embodiment. [Diagram 5] 2 is an enlarged plan view showing a part of the first liquid crystal unit according to the first embodiment. FIG. [Figure 6] 6 is a cross-sectional view of the first liquid crystal unit taken along line VI-VI in FIG. 5. [Figure 7] 1A is a plan view showing a first liquid crystal unit according to embodiment 1. FIG. 1B is a diagram showing the potential gradient of a liquid crystal layer according to embodiment 1. FIG. [Figure 8] FIG. 2 is a diagram showing an electrical configuration of the eyeglass system according to the first embodiment. [Figure 9] FIG. 11 is a perspective view showing an eyeglass system according to a second embodiment of the present invention. [Figure 10] FIG. 11 is a diagram showing an electrical configuration of an eyeglass system according to a second embodiment. [Figure 11] 10 is a flowchart showing a voltage control process according to the second embodiment. [Figure 12] FIG. 11 is a perspective view showing an eyeglass system according to a third embodiment of the present invention. [Figure 13] 13(a) is a schematic cross-sectional view of the optical element taken along line XIII-XIII in Fig. 12. (b) is a cross-sectional view showing a light-transmitting unit according to embodiment 3. [Figure 14] FIG. 11 is a diagram showing an electrical configuration of an eyeglass system according to a third embodiment. [Figure 15] FIG. 11 is a perspective view showing an eyeglass system according to a fourth embodiment of the present invention. [Figure 16] FIG. 11 is a diagram showing an electrical configuration of an eyeglass system according to a fourth embodiment. [Figure 17] FIG. 11 is a perspective view showing an eyeglass system according to a fifth embodiment of the present invention. [Figure 18] FIG. 13 is a diagram showing an electrical configuration of an eyeglass system according to a fifth embodiment. [Figure 19] 19(a) is a plan view showing an optical element according to a sixth embodiment of the present invention, (b) is a schematic cross-sectional view of the optical element taken along line XIXB-XIXB in Fig. 19(a), and (c) is a diagram showing the potential gradient of a liquid crystal layer according to the sixth embodiment. [Figure 20] FIG. 13 is a plan view showing a first liquid crystal unit according to Embodiment 6. [Figure 21] 21 is a cross-sectional view of the first liquid crystal unit taken along line XXI-XXI in FIG. 20. [Figure 22] FIG. 13 is a diagram showing an electrical configuration of an eyeglass system according to a sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and the description will not be repeated. In addition, in order to simplify the drawings, the oblique lines indicating cross sections are omitted as appropriate.

[0017] (Embodiment 1) An eyewear system 100 according to a first embodiment of the present invention will be described with reference to Fig. 1 to Fig. 8. Fig. 1 is a perspective view showing the eyewear system 100. As shown in Fig. 1, the eyewear system 100 includes glasses 1 and an operation device 200. The operation device 200 includes a main body a1 and a terminal a5, and is connectable to the glasses 1.

[0018] The glasses 1 control light that enters the eyes of a wearer HM of the glasses 1. The glasses 1 include a frame F, a pair of optical elements LN, a control unit 17, an operation unit 19, a battery 21, and a terminal 23. The optical elements LN function as lenses.

[0019] The frame F holds a pair of optical elements LN, and also has a control unit 17, an operation unit 19, a battery 21, and a terminal 23 mounted thereon.

[0020] Specifically, the frame F may include a pair of rims 3, a bridge 5, a pair of end pieces 7, a pair of hinges 9, a pair of temples 11, a pair of end pieces 13, and a pair of nose pads 15. The rims 3 hold the optical element LN. The bridge 5 connects one of the pair of rims 3 to the other of the pair of rims 3. The end piece 7 is located at the outer end of the rim 3 relative to the bridge 5. The end piece 7 connects the rim 3 to the temple 11 via the hinge 9. The hinge 9 supports the temple 11 rotatably relative to the end piece 7. The pair of temples 11 hold the head of the wearer HM. The end piece 13 covers the tip region of the temple 11 and contacts the upper part of the ear of the wearer HM.

[0021] Each of the optical elements LN converges light to function as a convex lens, or diverges light to function as a concave lens, under the control of the control unit 17. The control unit 17 controls the pair of optical elements LN based on an internal operation signal from the operation unit 19 or an external operation signal from the operation device 200. The operation unit 19 transmits an internal operation signal to the control unit 17 in response to an operation by the wearer HM. The control unit 17 and the operation unit 19 are installed in, for example, one of the pair of temples 11. The battery 21 supplies a power supply voltage to the control unit 17 and the operation unit 19. The battery 21 is installed in, for example, the other temple 11. The terminal 23 can be connected to a terminal a5 of the operation device 200. The terminal 23 is installed in, for example, one of the pair of end pieces 7.

[0022] The portion of the frame F in which the battery 21 is stored is preferably made of a material having better heat resistance than the other portions of the frame F. The battery 21 may also be equipped with a burnout prevention function to further improve safety. For example, a temperature sensor may be mounted near the battery 21, and a switch may be provided to cut off the electronic circuit constituting the control unit 17 when the temperature exceeds a specified temperature. Furthermore, a function for charging the battery 21 without contact may be mounted near the battery 21. Charging the battery 21 may be performed via a lead wire or without contact. The charging function through the lead wire and / or the charging function without contact may be incorporated in the case of the eyeglasses 1, and charging may be performed in conjunction with storing the eyeglasses 1 in the eyeglasses case. The case of the eyeglasses 1 and / or the eyeglasses 1 may also be provided with a solar cell to assist charging.

[0023] The operation device 200 transmits an external operation signal corresponding to the operation of the wearer HM to the control unit 17 via the terminal a5 and the terminal 23. Specifically, the main body a1 of the operation device 200 further includes a display a2, an operation key a3, and a speaker a4. The display a2 displays an image. The operation key a3 accepts an operation of the wearer HM. The main body a1 (specifically, the processor of the main body a1) transmits an external operation signal corresponding to the operation of the operation key a3 to the control unit 17. The speaker a4 outputs sound. The terminal a5 is detachable from the terminal 23 of the glasses 1. The operation device 200 may be, for example, a terminal dedicated to the glasses 1, or may be a mobile terminal such as a smartphone.

[0024] The operating device 200 may have a size that can be inserted into a card holder, for example. This is because when the eyeglasses 1 are worn with the operating device 200 always connected, the operating device 200 may be inserted into a card holder. In addition, in FIG. 1, a terminal (hereinafter, referred to as "terminal TL") is formed on an end surface corresponding to a short side of the substantially rectangular operating device 200. A cable extends from the terminal TL to a terminal a5. If the terminal TL is formed on the end surface corresponding to the short side, it is convenient when inserting the operating device 200 into a vertical card holder. However, the position of the terminal TL is not particularly limited, and for example, the terminal TL may be formed on an end surface corresponding to a long side of the operating device 200. If the terminal TL is formed on the end surface corresponding to the long side, it is convenient when inserting the operating device 200 into a horizontal card holder.

[0025] Furthermore, there is no particular limitation on the location of the terminal 23 of the eyeglasses 1. For example, assuming that the eyeglasses 1 are worn with the operating device 200 always connected (for example, when used for cataracts or farsightedness), the terminal 23 may be provided on the tip surface of the temple 11 (the tip surface of the end piece 13). For example, if the wearer HM is right-handed, it is preferable to provide the terminal 23 on the tip surface of the left temple 11 (the tip surface of the end piece 13) for the wearer HM.

[0026] Next, the optical element LN will be described with reference to FIG. 2. FIG. 2 is a schematic cross-sectional view of the optical element LN taken along line II-II in FIG. 1. As shown in FIG. 2, the optical element LN includes a first substrate 31, a first liquid crystal unit A1, a second substrate 33, a second liquid crystal unit A2, and a third substrate 35. The first liquid crystal unit A1 faces the eye EY of the wearer HM via the first substrate 31. Each of the first substrate 31, the second substrate 33, and the third substrate 35 has a flat plate shape and is made of, for example, glass or synthetic resin. The color of each of the first substrate 31, the second substrate 33, and the third substrate 35 is, for example, transparent or semi-transparent. The transparent color may be colorless and transparent, or may be colored and transparent. In addition, each of the first substrate 31, the second substrate 33, and the third substrate 35 may be made of a single substrate or may be made of multiple substrates. For example, the second substrate 33 may be made of multiple substrates bonded together. Furthermore, for example, the surfaces of the first substrate 31 and the third substrate 35 that come into contact with the outside air may be coated with an anti-reflection coating.

[0027] The first liquid crystal unit A1 is disposed between the first substrate 31 and the second substrate 33. The first liquid crystal unit A1 includes a liquid crystal layer 53 (hereinafter, may be referred to as "liquid crystal layer 53A"). The liquid crystal layer 53A refracts light in response to application of a control voltage CV. As a result, the liquid crystal layer 53A converges or diverges the light. Note that in the first embodiment, the control voltage CV includes a first voltage V1 and a second voltage V2.

[0028] The second liquid crystal unit A2 is disposed between the second substrate 33 and the third substrate 35. The second liquid crystal unit A2 faces the first liquid crystal unit A1 via the second substrate 33. The second liquid crystal unit A2 includes a liquid crystal layer 53 (hereinafter, may be referred to as "liquid crystal layer 53B"). The liquid crystal layer 53B refracts light in response to application of a control voltage CV. As a result, the liquid crystal layer 53B converges or diverges the light.

[0029] Each of the liquid crystal layers 53A and 53B includes liquid crystal. For example, the liquid crystal is a nematic liquid crystal, and the liquid crystal is aligned in a homogeneous orientation in a field-free environment in which no control voltage CV is applied to the liquid crystal layer 53. The color of the liquid crystal is, for example, transparent.

[0030] Specifically, in a plan view, the alignment direction of the liquid crystal in the liquid crystal layer 53A is approximately perpendicular to the alignment direction of the liquid crystal in the liquid crystal layer 53B. The plan view indicates that the optical element LN is viewed from the direction in which the optical axis C of the optical element LN extends. For example, the rubbing direction of the alignment material for the liquid crystal in the liquid crystal layer 53A is approximately perpendicular to the rubbing direction of the alignment material for the liquid crystal in the liquid crystal layer 53B. Note that the liquid crystal layers 53A and 53B are different in that the alignment directions of the liquid crystal are different, but the other configurations are similar to each other.

[0031] By providing the liquid crystal layer 53A and the liquid crystal layer 53B, the light incident on the optical element LN can be refracted effectively.

[0032] Specifically, one of the p-polarized and s-polarized components of the light (hereinafter referred to as "polarized component PA") is refracted by the liquid crystal layer 53A to which the control voltage CV is applied, and the other polarized component (hereinafter referred to as "polarized component PB") travels straight through the liquid crystal layer 53A. The polarized component PA is extraordinary light with respect to the liquid crystal layer 53A, and the polarized component PB is ordinary light with respect to the liquid crystal layer 53A.

[0033] Furthermore, the polarized component PA and the polarized component PB emitted from the liquid crystal layer 53A are incident on the liquid crystal layer 53B. Then, the polarized component PA travels straight through the liquid crystal layer 53B, and the polarized component PB is refracted by the liquid crystal layer 53B to which the control voltage CV is applied. This is because the orientation direction of the liquid crystal in the liquid crystal layer 53A is approximately perpendicular to the orientation direction of the liquid crystal in the liquid crystal layer 53B. The polarized component PA is ordinary light with respect to the liquid crystal layer 53B, and the polarized component PB is extraordinary light with respect to the liquid crystal layer 53B.

[0034] As a result of the above, both the p-polarized component and the s-polarized component of light can be refracted, so that the light incident on the optical element LN can be refracted effectively.

[0035] Next, the potential gradient formed in the liquid crystal layer 53 will be described with reference to Fig. 1 to Fig. 3(d). As shown in Fig. 1 and Fig. 2, the control unit 17 applies a control voltage CV to each of the liquid crystal layers 53A and 53B to form a sawtooth potential gradient in each of the liquid crystal layers 53A and 53B, thereby controlling the refraction of light. That is, the control unit 17 applies a control voltage CV to each of the liquid crystal layers 53A and 53B to form a sawtooth potential gradient in each of the liquid crystal layers 53A and 53B, thereby controlling the focal length of each of the liquid crystal layers 53A and 53B.

[0036] The control voltage CV is substantially (almost) the same for the liquid crystal layer 53A and the liquid crystal layer 53B. Therefore, the effective value, frequency, and waveform of the control voltage CV applied to the liquid crystal layer 53A are substantially (almost) the same as the effective value, frequency, and waveform of the control voltage CV applied to the liquid crystal layer 53B, respectively. As a result, the potential gradient formed in the liquid crystal layer 53A and the potential gradient formed in the liquid crystal layer 53B are substantially (almost) the same. However, in order to finely adjust the light refraction effect caused by the difference between the distance along the optical axis C from the eye EY to the liquid crystal layer 53A and the distance along the optical axis C from the eye EY to the liquid crystal layer 53B, the control voltage CV and other parameters may be controlled differently for the liquid crystal layer 53A and the liquid crystal layer 53B.

[0037] FIG. 3(a) is a diagram showing the potential gradient G of the liquid crystal layer 53 when the optical element LN functions as a convex lens. FIG. 3(b) is a diagram showing the focal length f of the optical element LN functioning as a convex lens. In FIG. 3(b), the shape of the optical element LN is made the same as that of a glass convex lens for ease of understanding, but the shape of the optical element LN does not change. FIG. 3(c) is a diagram showing the potential gradient H of the liquid crystal layer 53 when the optical element LN functions as a concave lens. FIG. 3(d) is a diagram showing the focal length f of the optical element LN functioning as a concave lens. In FIG. 3(d), the shape of the optical element LN is made the same as that of a glass concave lens for ease of understanding, but the shape of the optical element LN does not change.

[0038] 3(a), in response to application of a control voltage CV for realizing a convex lens, a sawtooth-shaped potential gradient G is formed in the liquid crystal layer 53. As a result, the liquid crystal layer 53 functions as a convex lens (specifically, a convex Fresnel lens). In other words, the optical element LN functions as a convex lens. For example, light LT incident on the liquid crystal layer 53 so as to be approximately perpendicular thereto is refracted and converged in response to the potential gradient G so as to approach the optical axis C.

[0039] 3(b), when the optical element LN functions as a convex lens, the focal length f of the optical element LN indicates a positive value. In other words, when the focal point FP of the optical element LN is located on the eye side of the wearer HM with respect to the optical element LN, the focal length f indicates a positive value. The focal length f indicates the distance from the center O of the optical element LN to the focal point FP.

[0040] 3(c), in response to application of a control voltage CV for realizing a concave lens, a sawtooth-shaped potential gradient H is formed in the liquid crystal layer 53. As a result, the liquid crystal layer 53 functions as a concave lens (specifically, a concave Fresnel lens). That is, the optical element LN functions as a concave lens. For example, light LT incident on the liquid crystal layer 53 approximately perpendicularly refracts and diverges away from the optical axis C in response to the potential gradient H.

[0041] 3(d), when the optical element LN functions as a concave lens, the focal length f of the optical element LN is a negative value. In other words, when the focus FP is located on the opposite side of the eye of the wearer HM (e.g., on the object side) with respect to the optical element LN, the focal length f is a negative value.

[0042] When both the liquid crystal layer 53A and the liquid crystal layer 53B function as a convex lens, the optical element LN functions as a convex lens. When both the liquid crystal layer 53A and the liquid crystal layer 53B function as a concave lens, the optical element LN functions as a concave lens. Since the thickness of the second substrate 33 of the optical element LN is relatively small, the focal length of the liquid crystal layer 53A and the focal length of the liquid crystal layer 53B can be considered to be substantially the same for the eyes of the wearer HM. Therefore, the focal length f of the optical element LN is indicated by the focal length of the liquid crystal layer 53A or the focal length of the liquid crystal layer 53B. In other words, the focal length f of the optical element LN, the focal length of the liquid crystal layer 53A, and the focal length of the liquid crystal layer 53B are substantially synonymous.

[0043] As described above with reference to Figs. 1 to 3(d), according to the first embodiment, the optical element LN includes the liquid crystal layer 53. In addition, the control unit 17 applies a control voltage CV to the liquid crystal layer 53 to control the refraction of light. Therefore, compared to a mechanical control mechanism, the time from the start to the completion of the control of the refraction of light can be shortened. As a result, high-speed control of the focal length f can be realized.

[0044] In addition, as described with reference to FIG. 3(a) and FIG. 3(d), according to the first embodiment, the control unit 17 applies the control voltage CV to the liquid crystal layer 53 so that a sawtooth potential gradient (potential gradient G or potential gradient H) is formed in the liquid crystal layer 53, thereby controlling the refraction of light. That is, the control unit 17 applies the control voltage CV to the liquid crystal layer 53 to form a sawtooth potential gradient (potential gradient G or potential gradient H) in the liquid crystal layer 53, thereby controlling the refraction of light. Therefore, each liquid crystal layer 53 functions as a Fresnel lens (convex or concave). As a result, the diameter of the optical element LN can be made relatively large while preventing the thickness of the optical element LN from becoming large. That is, the glasses 1 can be configured with the optical element LN having a practical thickness and diameter.

[0045] Next, the first liquid crystal unit A1 will be described with reference to Figures 4 to 7(b). The second liquid crystal unit A2 has the same configuration as the first liquid crystal unit A1.

[0046] Fig. 4 is a plan view showing the first liquid crystal unit A1, Fig. 5 is an enlarged plan view showing a part of the first liquid crystal unit A1, and Fig. 6 is a cross-sectional view of the first liquid crystal unit A1 taken along line VI-VI in Fig. 5.

[0047] 4 and 5, the first liquid crystal unit A1 includes a core electrode 50, a center electrode rc, unit electrodes r1 to r4, an insulating layer 51, a plurality of first boundary layers 61, a first lead wire 71, a second lead wire 72, and a third boundary layer 73. Each of the unit electrodes r1 to r4 includes a first electrode E1 and a second electrode E2. Each of the electrodes 50, rc, E1, E2, 71, and 72 is, for example, transparent. Each of the electrodes 50, rc, E1, E2, 71, and 72 is, for example, formed of ITO (Indium Tin Oxide).

[0048] The core electrode 50 has a disk-like shape. The disk-like shape refers to a circular planar shape. The core electrode 50 is surrounded by a center electrode rc. The core electrode 50 and the center electrode are made of the same material as the first electrode E1. The core electrode 50 has a radius Ra. The radius Ra indicates the distance from the center of gravity of the core electrode 50 to the outer edge of the core electrode 50. The optical axis C is approximately perpendicular to the core electrode 50 and passes through the center of gravity of the core electrode 50.

[0049] The core electrode 50, the center electrode rc, the unit electrodes r1 to r4, the first boundary layer 61, the first lead wire 71, the second lead wire 72, and the third boundary layer 73 are arranged in the same layer.

[0050] The core electrode 50, the center electrode rc, and the unit electrodes r1 to r4 are arranged concentrically around the core electrode 50. The core electrode 50 and the center electrode rc are electrically insulated from each other by an insulating layer 51. The insulating layer 51 is an electrical insulator. For example, the insulating layer 51 is transparent and is made of silicon dioxide (SiO2).

[0051] Between the center electrode rc and the unit electrode r1, between the unit electrode r1 and the unit electrode r2, between the unit electrode r2 and the unit electrode r3, and between the unit electrode r3 and the unit electrode r4, first boundary layers 61 are respectively disposed.

[0052] Each of the center electrode rc, the first electrode E1, and the second electrode E2 has a partially interrupted annular shape. The center electrode rc has a radius Rc. The radius Rc indicates the outer radius of the center electrode rc. Also, the unit electrodes r1 to r4 each have a radius R1 to a radius R4 (R4 > R3 > R2 > R1). The radius Rc is smaller than each of the radii R1 to R4. The unit electrodes r1 to r4 each have a width d1 to a width d4 (d4 < d3 < d2 < d1). The center electrode rc can be set to any size, but in order to improve the light utilization efficiency, it is preferable that the radius Rc is larger than each of the widths d1 to d4. Also, the center electrode rc has a width Kc. The width Kc indicates the width along the radial direction of the center electrode rc.

[0053] Here, the unit electrodes r1 to r4 may be collectively referred to as the unit electrode rn, the radius of the unit electrode rn among the radii R1 to R4 may be referred to as the radius Rn, and the width of the unit electrode rn among the widths d1 to d4 may be referred to as the width dn. The subscript n is an integer from 1 to N, where N is the number of the plurality of unit electrodes, and is assigned to each of the plurality of unit electrodes in ascending order from the unit electrode with the smallest radius to the unit electrode with the largest radius among the plurality of unit electrodes. N is the number of the plurality of unit electrodes, and in Embodiment 1, it is "4".

[0054] With reference to FIG. 5, the first liquid crystal unit A1 will be described continuously. As shown in FIG. 5, in each of the unit electrodes rn, the width dn is larger than the width K1 of the first electrode E1 and larger than the width K2 of the second electrode E2. The width dn indicates the distance between the first electrode E1 and the second electrode E2 in each of the unit electrodes rn. The width K1 indicates the width along the radial direction of the first electrode E1, and the width K2 indicates the width along the radial direction of the second electrode E2.

[0055] The radius Rn of the unit electrode rn is represented by the radius of the second electrode E2 constituting the unit electrode rn. The radius of the second electrode E2 represents the outer radius of the second electrode E2, and the radius of the first electrode E1 represents the outer radius of the first electrode E1. The farther the unit electrode rn is from the optical axis C, the larger the radius Rn of the unit electrode rn becomes.

[0056] The width dn of the unit electrode rn is represented by the distance between the outer edge of the first electrode E1 and the inner edge of the second electrode E2 that constitute the unit electrode rn. Among the unit electrodes rn adjacent to each other, the width dn of the unit electrode rn having a larger radius Rn is smaller than the width dn of the unit electrode rn having a smaller radius Rn. The unit electrodes rn surround the center electrode rc.

[0057] The first lead wire 71 extends from the core electrode 50 toward the first electrode E1 having the largest radius without contacting the second electrodes E2. The first lead wire 71 is linear. The first lead wire 71 is made of the same material as the first electrode E1.

[0058] The core electrode 50 is connected to a first lead wire 71. One end 81 of both ends of each of the first electrodes E1 is connected to the first lead wire 71. Therefore, a first voltage V1 serving as a control voltage CV is supplied from the first lead wire 71 to the core electrode 50 and the first electrode E1.

[0059] The radius Ra of the core electrode 50 is larger than the width Kc of the center electrode rc, the width K1 of the first electrode E1, or the width K2 of the second electrode E2. In the first embodiment, the radius Ra of the core electrode 50 is larger than each of the width Kc of the center electrode rc, the width K1 of the first electrode E1, and the width K2 of the second electrode E2. However, the radius Ra of the core electrode 50 is smaller than the inner radius of the center electrode rc.

[0060] The second lead wire 72 extends from the center electrode rc toward the second electrode E2 having the largest radius among the second electrodes E2 without contacting the first electrodes E1. The second lead wire 72 is linear. The second lead wire 72 is made of the same material as the second electrodes E2.

[0061] One end 93 of both ends of the center electrode rc is connected to the second lead wire 72. One end 91 of both ends of each of the second electrodes E2 is connected to the second lead wire 72. Therefore, a second voltage V2 as a control voltage CV is supplied from the second lead wire 72 to the center electrode rc and the second electrode E2.

[0062] The third boundary layer 73 contains the same electrical insulator as the insulating layer 51, and is formed of the same material as the insulating layer 51. Thus, the third boundary layer 73 is formed as a part of the insulating layer 51. Note that the third boundary layer 73 may be made of an electrical insulator different from that of the insulating layer 51. The third boundary layer 73 is disposed between the first lead wire 71 and the second lead wire 72.

[0063] The first liquid crystal unit A1 will now be described with reference to Fig. 6. As shown in Fig. 6, the first liquid crystal unit A1 includes a core electrode 50, a center electrode rc, unit electrodes r1 to r4, an insulating layer 51, and a plurality of first boundary layers 61, as well as a plurality of second boundary layers 62, a plurality of high resistance layers 52 (a plurality of resistance layers), a liquid crystal layer 53, and a third electrode E3. The structure of the first liquid crystal unit A1 is symmetrical with respect to the optical axis C.

[0064] The center electrode rc and the first electrode E1 of the unit electrode r1 are adjacent to each other via a first boundary layer 61. The second electrode E2 of one unit electrode rn and the first electrode E1 of the other unit electrode rn of the unit electrodes rn adjacent to each other are adjacent to each other via a first boundary layer 61. The first boundary layer 61 electrically insulates the center electrode rc and the first electrode E1 of the unit electrode r1, and also electrically insulates the second electrode E2 and the first electrode E1 adjacent to each other. The first boundary layer 61 contains the same electrical insulator as the insulating layer 51 and is formed of the same material as the insulating layer 51. Therefore, the first boundary layer 61 is formed as a part of the insulating layer 51. The first boundary layer 61 may be an electrical insulator different from the insulating layer 51.

[0065] The insulating layer 51 is disposed between the core electrode 50 and the center electrode rc and the high resistance layer 52, and electrically insulates the core electrode 50 and the center electrode rc from the high resistance layer 52. The insulating layer 51 is disposed between the first electrode E1 and the second electrode E2 and the high resistance layer 52, and electrically insulates the first electrode E1 and the second electrode E2 from the high resistance layer 52. The insulating layer 51 is disposed between the core electrode 50 and the center electrode rc and electrically insulates the core electrode 50 from the center electrode rc. The insulating layer 51 is disposed between the first electrode E1 and the second electrode E2 in each unit electrode rn and electrically insulates the first electrode E1 from the second electrode E2.

[0066] The insulating layer 51 has a thickness ts. The thickness ts indicates the thickness of a portion of the insulating layer 51 located between the first electrode E1 and the high resistance layer 52, the thickness of a portion of the insulating layer 51 located between the second electrode E2 and the high resistance layer 52, the thickness of a portion of the insulating layer 51 located between the core electrode 50 and the high resistance layer 52, or the thickness of a portion of the insulating layer 51 located between the center electrode rc and the high resistance layer 52.

[0067] The multiple high resistance layers 52 and the multiple second boundary layers 62 are arranged in the same layer. Of the multiple high resistance layers 52, the innermost high resistance layer 52 has a disk shape and faces the core electrode 50 and the center electrode rc via the insulating layer 51. The other multiple high resistance layers 52 each face the unit electrodes r1 to r4 via the insulating layer 51 and are circular band-like.

[0068] The high resistance layer 52 is disposed between the core electrode 50 and the center electrode rc and the liquid crystal layer 53. The high resistance layer 52 is disposed between the unit electrode rn and the liquid crystal layer 53. That is, each of the high resistance layers 52 is disposed between the insulating layer 51 and the third electrode E3. Specifically, each of the high resistance layers 52 is disposed between the insulating layer 51 and the liquid crystal layer 53. The electrical resistivity (specific resistance) of the high resistance layer 52 is greater than the electrical resistivity of the core electrode 50, the electrical resistivity of the center electrode rc, the electrical resistivity of the first electrode E1, and the electrical resistivity of the second electrode E2, and is less than the electrical resistivity of the insulating layer 51. For example, the color of the high resistance layer 52 is transparent, and the high resistance layer 52 is made of zinc oxide (ZnO).

[0069] The electrical resistivity of the high resistance layer 52 is set to, for example, a suitable electrical resistivity. The suitable electrical resistivity is an electrical resistivity suitable for forming a potential gradient in the liquid crystal layer that can realize a desired refraction angle.

[0070] The high resistance layer 52 has a thickness th. The thickness ts of the insulating layer 51 is smaller than the thickness th of the high resistance layer 52. Therefore, it is possible to suppress the concentration of equipotential lines approximately parallel to the radial direction RD of the first liquid crystal unit A1 in the part of the insulating layer 51 between the second electrode E2 and the high resistance layer 52 and in the part between the first electrode E1 and the high resistance layer 52. As a result, it is possible to reduce the drop and rise of the potential in the part of the insulating layer 51 between the second electrode E2 and the high resistance layer 52 and in the part between the first electrode E1 and the high resistance layer 52. Hereinafter, such a drop and rise of the potential may be referred to as a "potential smoothing phenomenon." The radial direction RD is a direction perpendicular to the optical axis C and faces in a direction away from the optical axis C.

[0071] In general, the potential smoothing phenomenon becomes more prominent as the width dn of the unit electrode rn becomes smaller. In general, the potential smoothing phenomenon changes the preferred frequency and the preferred electrical resistivity. The preferred frequency is a frequency suitable for forming a potential gradient in the liquid crystal layer that can realize a desired refraction angle.

[0072] In contrast, in the first embodiment, the potential smoothing phenomenon is reduced by making the thickness ts of the insulating layer 51 smaller than the thickness th of the high resistance layer 52. Therefore, the potential smoothing phenomenon can be reduced without depending on the width dn of the unit electrode rn. As a result, it is possible to suppress the preferred frequency and the preferred electrical resistivity from changing depending on the width dn (electrode spacing) of the unit electrode rn. For example, the frequency f1 of the first voltage V1 is set to one of a plurality of preferred frequencies, and the frequency f2 of the second voltage V2 is set to one of a plurality of preferred frequencies.

[0073] The smaller the thickness ts of the insulating layer 51, the better as long as insulation between the core electrode 50 and the center electrode rc and the high resistance layer 52, and insulation between the first electrode E1 and the second electrode E2 and the high resistance layer 52 are maintained. This is because the smaller the thickness ts of the insulating layer 51, the more the preferred frequency and the preferred electrical resistivity can be suppressed from changing depending on the width dn of the unit electrode rn.

[0074] A second boundary layer 62 is disposed between adjacent high-resistance layers 52. The second boundary layer 62 contains the same electrical insulator as the insulating layer 51 and is formed of the same material as the insulating layer 51. Therefore, the second boundary layer 62 is formed as a part of the insulating layer 51. Note that the second boundary layer 62 may be made of an electrical insulator different from that of the insulating layer 51.

[0075] The width of the second boundary layer 62 is approximately the same as the width of the first boundary layer 61. The width of the second boundary layer 62 indicates the width of the second boundary layer 62 along the radial direction. The width of the first boundary layer 61 indicates the width of the first boundary layer 61 along the radial direction. The second boundary layer 62 faces the first boundary layer 61 with the insulating layer 51 interposed therebetween.

[0076] The liquid crystal layer 53 includes liquid crystal. The liquid crystal layer 53 is disposed between the unit electrode rn and the third electrode E3, and is disposed between the core electrode 50 and the center electrode rc and the third electrode E3. The liquid crystal layer 53 is disposed between the insulating layer 51 and the third electrode E3. Specifically, the liquid crystal layer 53 is disposed between the high resistance layer 52 and the third electrode E3. The liquid crystal layer 53 has a thickness tq.

[0077] A third voltage V3 is applied to the third electrode E3. In the first embodiment, the third electrode E3 is grounded, and the third voltage V3 is set to the ground potential (0V). The third electrode E3 is planar and formed as a single layer. The third electrode E3 faces the core electrode 50, the center electrode rc, and the unit electrode rn via the liquid crystal layer 53, the high resistance layer 52, and the insulating layer 51. For example, the electrical resistivities of the first electrode E1, the second electrode E2, and the third electrode E3 are substantially the same.

[0078] The core electrode 50, the center electrode rc, and the unit electrodes r1 to r4 are closer to the eyes than the liquid crystal layer 53.

[0079] As described above with reference to Figs. 4 to 6, according to the first embodiment, the first electrode E1 and the second electrode E2 are insulated by the insulating layer 51, and the core electrode 50 and the center electrode rc are insulated by the insulating layer 51. Therefore, no current flows between the first electrode E1 and the second electrode E2, and no current flows between the core electrode 50 and the center electrode rc. As a result, power loss in the first liquid crystal unit A1 can be suppressed. The same applies to the second liquid crystal unit A2.

[0080] According to the first embodiment, the width dn of the unit electrode rn is smaller as it is farther from the optical axis C. On the other hand, since the thickness ts of the insulating layer 51 is smaller than the thickness th of the high resistance layer 52, it is possible to suppress the preferred frequency and the preferred electrical resistivity from varying depending on the width dn of the unit electrode rn. Therefore, it is not required to make the frequency f1 of the first voltage V1 and the frequency f2 of the second voltage V2 different between the unit electrode rn close to the optical axis C and the unit electrode rn far from the optical axis C, and furthermore, it is not required to make the electrical resistivity of the high resistance layer 52 different. As a result, it is possible to suppress the design of the first liquid crystal unit A1 from becoming complicated, and to suppress the manufacturing cost of the first liquid crystal unit A1 from increasing. The same is true for the second liquid crystal unit A2.

[0081] Next, the potential gradient G formed in the liquid crystal layer 53 will be described with reference to Figs. 6 to 7(b). Fig. 7(a) is a plan view showing the first liquid crystal unit A1. In Fig. 7(a), the first lead wire 71, the second lead wire 72, and the third boundary layer 73 are omitted for the sake of simplicity. In addition, in order to simplify the drawing, the center electrode rc, the first electrode E1, and the second electrode E2 are shown as continuous annular shapes. Fig. 7(b) is a diagram showing the potential gradient G in the liquid crystal layer 53. Fig. 7(b) shows the potential gradient G appearing in a cross section taken along line VIIB-VIIB in Fig. 7(a).

[0082] 6 to 7(b), when the first voltage V1 is smaller than the second voltage V2, when the first voltage V1 is applied to the core electrode 50 and each first electrode E1 and the second voltage V2 is applied to the center electrode rc and each second electrode E2, a sawtooth-shaped potential gradient G (solid line) symmetrical with respect to the optical axis C is formed in the liquid crystal layer 53 due to the presence of the high-resistance layer 52, the first boundary layer 61, and the second boundary layer 62. In other words, when the first liquid crystal unit A1 is viewed in a plan view (that is, when the first liquid crystal unit A1 is viewed from the direction in which the optical axis C extends), the potential gradient G is formed in a concentric shape.

[0083] In this specification, the first voltage V1 being smaller than the second voltage V2 means that at least the voltage value v1 of the first voltage V1 is smaller than the voltage value v2 of the second voltage V2.

[0084] The potential gradient G includes a potential gradient Gc formed corresponding to the core electrode 50 and the center electrode rc, a potential gradient G1 formed corresponding to the unit electrode r1, a potential gradient G2 formed corresponding to the unit electrode r2, a potential gradient G3 formed corresponding to the unit electrode r3, and a potential gradient G4 formed corresponding to the unit electrode r4. Each of the potential gradient Gc and the potential gradients G1 to G4 is a potential gradient with respect to the radial direction RD of the first liquid crystal unit A1.

[0085] Due to the action of the high resistance layer 52, the potential gradient Gc and each of the potential gradients G1 to G4 are smooth curves without steps or extreme values ​​(minimum and maximum values).

[0086] The potential gradient Gc is expressed by, for example, a quadratic curve. Each of the potential gradient Gc and the potential gradients G1 to G4 is formed so that the potential increases from the optical axis C toward the radial direction RD. Moreover, the potential gradient Gc and the potential gradients G1 to G4 have a steeper slope as they move away from the optical axis C.

[0087] When a potential gradient G is formed in the liquid crystal layer 53, a refractive index gradient corresponding to the potential gradient G is formed in the liquid crystal layer 53. As a result, the incident light incident on the liquid crystal layer 53 is refracted so as to approach the optical axis C at a refraction angle corresponding to each of the potential gradient Gc and the potential gradients G1 to G4, and is output from the liquid crystal layer 53 as output light. Since the potential gradient becomes steeper as it moves away from the optical axis C, the refraction angle becomes larger as it moves away from the optical axis C, and the output light is focused toward the optical axis C. As a result, the first liquid crystal unit A1 can function as a convex Fresnel lens.

[0088] On the other hand, when the first voltage V1 is greater than the second voltage V2, when the first voltage V1 is applied to the core electrode 50 and each first electrode E1 and the second voltage V2 is applied to the center electrode rc and each second electrode E2, a sawtooth-shaped potential gradient H (two-dot chain line) symmetrical with respect to the optical axis C is formed in the liquid crystal layer 53 due to the presence of the high resistance layer 52, the first boundary layer 61, and the second boundary layer 62. In other words, when the first liquid crystal unit A1 is viewed in a plane, the potential gradient H is formed in a concentric shape.

[0089] In this specification, the first voltage V1 being greater than the second voltage V2 means that at least the voltage value v1 of the first voltage V1 is greater than the voltage value v2 of the second voltage V2. Moreover, the first voltage V1 and the second voltage V2 being the same means that the voltage value v1 and the voltage value v2 are the same, and the frequency f1 of the first voltage V1 and the frequency f2 of the second voltage V2 are the same.

[0090] The potential gradient H includes a potential gradient Hc formed corresponding to the core electrode 50 and the center electrode rc, a potential gradient H1 formed corresponding to the unit electrode r1, a potential gradient H2 formed corresponding to the unit electrode r2, a potential gradient H3 formed corresponding to the unit electrode r3, and a potential gradient H4 formed corresponding to the unit electrode r4. Each of the potential gradient Hc and the potential gradients H1 to H4 is a potential gradient with respect to the radial direction RD of the first liquid crystal unit A1.

[0091] Due to the action of the high resistance layer 52, each of the potential gradient Hc and the potential gradients H1 to H4 is a smooth curve without any steps or extreme values ​​(minimum and maximum values).

[0092] The potential gradient Hc is expressed by, for example, a quadratic curve. Each of the potential gradient Hc and the potential gradients H1 to H4 is formed so that the potential decreases from the optical axis C toward the radial direction RD. Moreover, the potential gradient Hc and the potential gradients H1 to H4 have a steeper slope as they move away from the optical axis C.

[0093] When a potential gradient H is formed in the liquid crystal layer 53, a refractive index gradient corresponding to the potential gradient H is formed in the liquid crystal layer 53. As a result, the incident light incident on the liquid crystal layer 53 is refracted away from the optical axis C at a refraction angle corresponding to each of the potential gradient Hc and the potential gradients H1 to H4, and is output from the liquid crystal layer 53 as output light. Since the slope of the potential gradient becomes steeper as it moves away from the optical axis C, the refraction angle becomes larger as it moves away from the optical axis C, and the output light is diverged away from the optical axis C. As a result, the first liquid crystal unit A1 can function as a concave Fresnel lens.

[0094] As described above with reference to FIG. 6 to FIG. 7(b), according to the first embodiment, the high resistance layer 52 is provided corresponding to the core electrode 50 and the center electrode rc, and a plurality of high resistance layers 52 are provided corresponding to a plurality of unit electrodes rn. Therefore, the potential gradient Gc and each of the potential gradients G1 to G4, and the potential gradient Hc and each of the potential gradients H1 to H4 are smooth curves without steps. Therefore, the wavefront aberration of the emitted light can be suppressed. Furthermore, the potential gradient Gc and each of the potential gradients G1 to G4, and the potential gradient Hc and each of the potential gradients H1 to H4 do not have extreme values. Therefore, the incident light can be refracted with high accuracy, and the first liquid crystal unit A1 can form a highly accurate Fresnel lens. The same is true for the second liquid crystal unit A2.

[0095] Next, the operation of the glasses 1 will be described with reference to Fig. 8. Fig. 8 is a diagram showing the electrical configuration of the glasses system 100. As shown in Fig. 8, the control unit 17 of the glasses 1 includes a controller 55, a first power supply circuit PW1, and a second power supply circuit PW2. The controller 55 includes a processor 57 and a memory 59. The operation unit 19 includes a first switch 65 and a second switch 67.

[0096] The controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2. Specifically, the processor 57 executes a computer program stored in the memory 59 to control the first power supply circuit PW1 and the second power supply circuit PW2. The memory 59 stores various data and computer programs.

[0097] The first power supply circuit PW1, under the control of the controller 55, applies a first voltage V1 to the core electrode 50 and the first electrodes E1 of each of the first liquid crystal unit A1 and the second liquid crystal unit A2 via the first lead wires 71 of each of the first liquid crystal unit A1 and the second liquid crystal unit A2. The first voltage V1 is an example of a control voltage CV. The first voltage V1 is an AC voltage and has a frequency f1. The first voltage V1 is, for example, a square wave. The first voltage V1 has an effective value V1e and a maximum amplitude V1m. The first voltage V1 has a voltage value v1.

[0098] The second power supply circuit PW2, under the control of the controller 55, applies a second voltage V2 to the center electrode rc and the second electrodes E2 of each of the first liquid crystal unit A1 and the second liquid crystal unit A2 via the second lead wires 72 of each of the first liquid crystal unit A1 and the second liquid crystal unit A2. The second voltage V2 is an example of a control voltage CV. The second voltage V2 is an AC voltage and has a frequency f2. The second voltage V2 is, for example, a square wave. The second voltage V2 has an effective value V2e and a maximum amplitude V2m. In addition, the second voltage V2 has a voltage value v2.

[0099] By applying a first voltage V1 to the core electrode 50 and the multiple first electrodes E1 and applying a second voltage V2 to the center electrode rc and the multiple second electrodes E2, the first voltage V1 and the second voltage V2 are applied to the liquid crystal layer 53, and a potential gradient is formed in the liquid crystal layer 53.

[0100] The controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 in response to an internal operation signal from the operation unit 19 or an external operation signal from the operation device 200 to control the first voltage V1 and the second voltage V2. By controlling the first voltage V1 and the second voltage V2, the potential gradient of the liquid crystal layer 53 can be controlled. Specifically, the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 to control the difference value DFF (=V1-V2) between the first voltage V1 and the second voltage V2. By controlling the difference value DFF, the potential gradient of the liquid crystal layer 53 can be controlled. As a result, the focal length f of the optical element LN can be controlled.

[0101] In this specification, the control of the first voltage V1 and the second voltage V2 by the controller 55 may be the control of the voltage value v1 and the voltage value v2, the control of the frequency f1 and the frequency f2, or the control of the voltage value v1 and the voltage value v2 and the frequency f1 and the frequency f2. The control of the difference value DFF by the controller 55 may be the control of the difference value DV (=v1-v2) between the voltage value v1 and the voltage value v2, the control of the difference value DF (=f1-f2) between the frequency f1 and the frequency f2, or the control of the difference value DV and the difference value DF. In order to form a potential gradient in the liquid crystal layer 53, it is sufficient that at least the voltage value v1 and the voltage value v2 are different, and the difference value DF may be zero. In addition, the potential gradient in the liquid crystal layer 53 can be eliminated by making the difference value DV zero.

[0102] More specifically, when the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the voltage value v1 of the first voltage V1 is smaller than the voltage value v2 of the second voltage V2, the optical element LN (specifically, the liquid crystal layer 53) functions as a convex lens. This is because a potential gradient G (FIG. 3(a)) is formed in the liquid crystal layer 53. Also, when the voltage value v1 is smaller than the voltage value v2, the greater the absolute value of the difference value DV (=v1-v2) between the voltage values ​​v1 and v2, the smaller the absolute value of the focal length f of the optical element LN as a convex lens becomes. Therefore, when the voltage value v1 is smaller than the voltage value v2, when the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the absolute value of the difference value DV increases, the absolute value of the focal length f of the optical element LN as a convex lens decreases.

[0103] In this specification, the voltage value v1 indicates the effective value V1e or maximum amplitude V1m of the first voltage V1. The voltage value v2 indicates the effective value V2e or maximum amplitude V2m of the second voltage V2. Furthermore, the difference value DV indicates the difference between the effective value V1e and the effective value V2e (=V1e-V2e) or the difference between the maximum amplitude V1m and the maximum amplitude V2m (=V1m-V2m).

[0104] Furthermore, when the voltage value v1 is smaller than the voltage value v2 and the frequency f1 is lower than the frequency f2, the greater the absolute value of the difference value DF (=f1-f2) between the frequencies f1 and f2, the smaller the absolute value of the focal length f of the optical element LN as a convex lens. Therefore, when the voltage value v1 is smaller than the voltage value v2 and the frequency f1 is lower than the frequency f2, if the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the absolute value of the difference value DF increases, the absolute value of the focal length f of the optical element LN as a convex lens decreases.

[0105] On the other hand, when the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the voltage value v1 of the first voltage V1 is greater than the voltage value v2 of the second voltage V2, the optical element LN (specifically, the liquid crystal layer 53) functions as a concave lens. This is because a potential gradient H (FIG. 3(d)) is formed in the liquid crystal layer 53. When the voltage value v1 is greater than the voltage value v2, the greater the absolute value of the difference value DV between the voltage values ​​v1 and v2, the smaller the absolute value of the focal length f of the optical element LN as a concave lens becomes. Therefore, when the voltage value v1 is greater than the voltage value v2, when the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the absolute value of the difference value DV increases, the absolute value of the focal length f of the optical element LN as a concave lens decreases.

[0106] Furthermore, when the voltage value v1 is greater than the voltage value v2 and the frequency f1 is higher than the frequency f2, the greater the absolute value of the difference value DF between the frequencies f1 and f2, the smaller the absolute value of the focal length f of the optical element LN as a concave lens. Therefore, when the voltage value v1 is greater than the voltage value v2 and the frequency f1 is higher than the frequency f2, if the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the absolute value of the difference value DF increases, the absolute value of the focal length f of the optical element LN as a concave lens decreases.

[0107] Furthermore, when the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the voltage value v1 and the voltage value v2 are the same and the frequency f1 and the frequency f2 are the same, the potential gradient of the liquid crystal layer 53 disappears. Therefore, the optical element LN loses its function as a convex lens and a concave lens. As a result, the optical element LN does not converge or diverge light, and light that is perpendicularly incident on the optical element LN travels straight.

[0108] For example, when the wearer HM presses the first switch 65, the first switch 65 transmits a first internal operation signal to the controller 55. Upon receiving the first internal operation signal, the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the absolute value of the difference value DFF (e.g., the difference value DV) increases. As a result, the absolute value of the focal length f decreases.

[0109] On the other hand, for example, when the wearer HM presses the second switch 67, the second switch 67 transmits a second internal operation signal to the controller 55. Upon receiving the second internal operation signal, the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the absolute value of the difference value DFF (for example, the difference value DV) decreases. As a result, the absolute value of the focal length f increases.

[0110] For example, the first switch 65 is arranged on the upper end surface of one of the pair of temples 11 (hereinafter, in this example, referred to as the "specific temple 11"), and the second switch 67 is arranged on the lower end surface of the specific temple 11. It is preferable that the position of the first switch 65 arranged on the upper end surface of the specific temple 11 is farther from the hinge 9 than the position of the second switch 67 arranged on the lower end surface of the specific temple 11. This is because, by holding the specific temple 11 between the index finger and thumb, the first switch 65 on the upper end surface can be easily operated with the index finger, and the second switch 67 on the lower end surface can be easily operated with the thumb.

[0111] As described above with reference to FIG. 8, according to the first embodiment, the potential gradient of the liquid crystal layer 53 can be easily controlled by controlling the control voltage CV (specifically, the first voltage V1 and the second voltage V2). Therefore, by controlling the control voltage CV, the focal length f of the optical element LN can be easily changed over a relatively wide range from a negative value (corresponding to a concave lens) to a positive value (corresponding to a convex lens). In other words, the power of the glasses 1 can be easily changed over a wide range. In particular, since a sawtooth-shaped potential gradient is formed, the focal length f of the optical element LN can be changed over an even wider range by controlling the control voltage CV while preventing the thickness of the optical element LN from increasing.

[0112] (Embodiment 2) A glasses system 100A according to a second embodiment of the present invention will be described with reference to Fig. 9 to Fig. 11. The glasses system 100A mainly differs from the glasses system 100 according to the first embodiment in that the focal length f is controlled according to the line of sight of the wearer HM. Below, the differences between the second embodiment and the first embodiment will be mainly described.

[0113] Fig. 9 is a perspective view showing the eyeglass system 100A. Fig. 10 is a diagram showing the electrical configuration of the eyeglass system 100A.

[0114] 9, the eyewear system 100A includes glasses 1A and an operation device 200. In addition to the configuration of the glasses 1 according to the first embodiment, the glasses 1A further include a pair of eye detection units 75. The eye detection unit 75 detects the movement of the eyes of the wearer HM. Specifically, the pair of eye detection units 75 detect the movement of the left eye and the right eye of the wearer HM, respectively.

[0115] The pair of eye detection units 75 are mounted on the frame F. Specifically, one of the pair of eye detection units 75 is installed on one of the pair of rims 3 (e.g., on an upper portion of one of the rims 3). The other eye detection unit 75 is installed on the other rim 3 (e.g., on an upper portion of the other rim 3).

[0116] The control unit 17 controls the control voltage CV of the liquid crystal layer 53 based on the detection result of the eye detection unit 75.

[0117] As a result, according to the second embodiment, the potential gradient of the liquid crystal layer 53 is controlled and the focal length f of the optical element LN can be changed without the wearer HM operating the operation unit 19 and the operation device 200. That is, the focal length f of the optical element LN can be automatically changed according to the detection result of the eye movement by the eye detection unit 75. Since the focal length f can be automatically changed, the convenience of the wearer HM can be improved. When the focal length f is automatically changed, the power of the optical element LN is automatically changed.

[0118] Specifically, as shown in FIG. 10, the controller 55 executes an eye tracking technique to calculate the line of sight direction SLL of one eye of the wearer HM and the line of sight direction SLR of the other eye based on the detection results of the eye detection unit 75. Then, the controller 55 controls the control voltage CV of the liquid crystal layer 53 based on the line of sight direction SLL and / or the line of sight direction SLR. Therefore, the potential gradient of the liquid crystal layer 53 is controlled according to the line of sight direction SLL and / or the line of sight direction SLR. As a result, the focal length f of the optical element LN is changed according to the line of sight direction SLL and / or the line of sight direction SLR. The controller 55 can also calculate the position of the gaze point of the wearer HM from the line of sight direction SLL and the line of sight direction SLR. The gaze point is the intersection of the line of sight direction SLL and the line of sight direction SLR.

[0119] In a first example of the eye tracking technology, the eye detection unit 75 optically detects the movement of the eye, and the controller 55 calculates the gaze direction based on the detection result of the eye detection unit 75. As specific examples of the first example, the corneal reflex method, the dark pupil method, the light pupil method, and the scleral reflex method will be described.

[0120] In the corneal reflex method, the dark pupil method, and the bright pupil method, each of the eye detection unit 75 includes a light source such as an LED (Light Emitting Diode) and an imaging unit such as a camera (for example, a video camera).

[0121] In the corneal reflex method, a light source irradiates light (e.g., infrared light) onto the eye, and an imaging unit captures an image of the eye. The controller 55 detects the position of the pupil and the position of the corneal reflection image (specifically, the Purkinje image) of the light source on the corneal surface from the image of the eye output by the imaging unit. Furthermore, the controller 55 calculates the gaze direction based on the position of the pupil and the position of the corneal reflection image of the light source.

[0122] In the dark pupil method, a light source is installed at a position away from the lens optical axis of the imaging unit. The light source irradiates light (e.g., infrared light) onto the eye, and the imaging unit captures an image of the eye. In the image of the eye output by the imaging unit, the pupil portion becomes dark. Therefore, the controller 55 extracts the dark pupil portion from the image, and calculates the gaze direction based on the movement of the pupil portion.

[0123] Furthermore, in the bright pupil method, a light source is installed so that its optical axis is coaxial with the lens optical axis of the imaging unit. The light source then irradiates light (e.g., infrared light) onto the eye, and the imaging unit captures an image of the eye. In the image of the eye output by the imaging unit, the pupil portion becomes bright. Therefore, the controller 55 extracts the bright pupil portion from the image, and calculates the gaze direction based on the movement of the pupil portion.

[0124] As another example of using the pupil portion to detect the eye condition, information on the degree of pupil opening may be detected to control the light transmittance of the glasses 1A. This example is effective when the wearer HM suffers from photophobia, as described below. Furthermore, since there is a phenomenon in which the pupil generally contracts when looking at something close, the degree of pupil opening and the speed at which the pupil opens can also be converted into the distance of the viewpoint.

[0125] In the scleral reflex method, each of the eye detection units 75 includes a light-emitting element such as a light-emitting diode and a light-receiving element such as a photodiode or a phototransistor. The light-emitting element irradiates light (e.g., infrared light) onto the boundary between the cornea and the sclera of the eye, and the light-receiving element receives the reflected light from the boundary. When the eye moves, the ratio of the part of the light (e.g., a light spot) that covers the cornea to the part that covers the sclera changes, and the amount of reflected light changes. Therefore, the light-receiving element measures the amount of reflected light, and the controller 55 calculates the gaze direction based on the change in the amount of reflected light.

[0126] In a second example of eye tracking technology, the gaze direction is detected by electrooculography. Specifically, the eye detection units 75 detect the potential difference between two points around the eye, and the controller 55 calculates the rotation angle of the eyeball based on the potential difference. Then, the controller 55 calculates the gaze direction based on the rotation angle of the eyeball. In the electrooculography, each of the eye detection units 75 includes two electrodes attached to two points around the eye and a potentiometer that detects the potential difference between the two electrodes.

[0127] Next, the voltage control process based on the line of sight will be described with reference to Fig. 11. Fig. 11 is a flowchart showing the voltage control process. In the explanation of Fig. 11, the difference value DFF (=V1-V2) between the first voltage V1 and the second voltage V2 indicates the difference value DV (=v1-v2). As shown in Fig. 11, the routine includes steps S1 to S13.

[0128] In step S1, the controller 55 executes an eye tracking technique to calculate the gaze direction SLL and the gaze direction SLR based on the detection results of the eye detection unit 75. In addition, when calculating the gaze direction SLL and the gaze direction SLR, the controller 55 calculates an angle θL between the gaze direction SLL and the horizontal plane, and an angle θR between the gaze direction SLR and the horizontal plane.

[0129] In step S3, the controller 55 calculates the average value θLR of the angle θL and the angle θR.

[0130] In step S5, the controller 55 determines whether the average value θLR indicates a depression angle and is equal to or greater than a predetermined angle θth. The predetermined angle θth is, for example, greater than zero degrees and less than 90 degrees. The depression angle indicates a downward angle with respect to a horizontal plane.

[0131] If the determination in step S5 is positive, that is, if it is determined that the average value θLR indicates a depression angle and is equal to or greater than the predetermined angle θth (Yes in step S5), the controller 55 advances the process to step S7. A positive determination in step S5 indicates that the wearer HM's line of sight is directed downward relative to the horizontal plane. On the other hand, a negative determination in step S5 indicates that the wearer HM's line of sight is directed horizontally or upward relative to the horizontal plane.

[0132] In step S7, the controller 55 determines whether or not a positive determination was made in the previous step S5. The previous step S5 indicates the step S5 executed in the previous routine.

[0133] If it is determined that a positive determination was made in the previous step S5 (Yes in step S7), the controller 55 advances the process to step S1.

[0134] On the other hand, if it is determined that the previous determination in step S5 was not affirmative (No in step S7), the controller 55 advances the process to step S9.

[0135] In step S9, the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the difference value DFF between the first voltage V1 and the second voltage V2 is changed relative to the current difference value DFF. As a result, the focal length f of the optical element LN changes according to the difference value DFF. Then, the process proceeds to step S1.

[0136] Specifically, the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the difference value DFF indicates a negative value.

[0137] For example, the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the difference value DFF changes from a first predetermined value PV1 to a second predetermined value PV2. For example, the first predetermined value PV1 is zero, and the second predetermined value PV2 is a negative value. In this example, when the difference value DFF changes from the first predetermined value PV1 to the second predetermined value PV2, each of the optical elements LN changes from a state in which it has lost its function as a convex lens and a concave lens to a convex lens. For example, the first predetermined value PV1 is a positive value, and the second predetermined value PV2 is a negative value. In this example, when the difference value VD changes from the first predetermined value PV1 to the second predetermined value PV2, each of the optical elements LN changes from a concave lens to a convex lens.

[0138] On the other hand, if a negative determination is made in step S5 (No in step S5), the controller 55 advances the process to step S11. A negative determination in step S5 indicates that the average value θLR indicates an elevation angle, or that the average value θLR indicates a depression angle and is smaller than a predetermined angle θth. The elevation angle indicates an upward angle with respect to the horizontal plane.

[0139] In step S11, the controller 55 determines whether or not a negative determination was made in the previous step S5.

[0140] If it is determined that a negative determination was made in the previous step S5 (Yes in step S11), the controller 55 advances the process to step S1.

[0141] On the other hand, if it is determined that a negative determination was not made in the previous step S5 (No in step S11), the controller 55 advances the process to step S13.

[0142] In step S13, the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the difference value DFF between the first voltage V1 and the second voltage V2 is changed relative to the current difference value DFF. As a result, the focal length f of the optical element LN changes according to the difference value DFF. Then, the process proceeds to step S1.

[0143] Specifically, the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the difference value DFF indicates zero or a positive value.

[0144] For example, the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the difference value DFF changes from the second predetermined value PV2 to the first predetermined value PV1. For example, the second predetermined value PV2 is a negative value, and the first predetermined value PV1 is zero. In this example, when the difference value DFF changes from the second predetermined value PV2 to the first predetermined value PV1, each of the optical elements LN changes from a convex lens to a state in which it loses its functions as a convex lens and a concave lens. For example, the second predetermined value PV2 is a negative value, and the first predetermined value PV1 is a positive value. In this example, when the difference value DFF changes from the second predetermined value PV2 to the first predetermined value PV1, each of the optical elements LN changes from a convex lens to a concave lens.

[0145] Note that step S3 may be omitted. If step S3 is omitted, in step S5, controller 55 determines whether or not either angle θL or angle θR indicates a depression angle and is equal to or greater than a predetermined angle θth.

[0146] As described above with reference to FIG. 11, according to the second embodiment, the focal length f of the optical element LN can be changed in accordance with the line of sight direction SLL and / or the line of sight direction SLR without the wearer HM operating the operation unit 19 and the operation device 200.

[0147] For example, when the line of sight of the wearer HM with normal vision is directed upward or horizontally from the horizontal plane (for example, when the wearer HM is viewing an object at a medium or long distance), the optical element LN changes from a convex lens to a state in which it has lost its functions as a convex lens and a concave lens (step S13), or the optical element LN is maintained in a state in which it has lost its functions as a convex lens and a concave lens (Yes in step S11). On the other hand, when the line of sight of the wearer HM with normal vision is directed downward from the horizontal direction (for example, when the wearer HM is viewing an object at a close distance), the optical element LN changes from a state in which it has lost its functions as a convex lens and a concave lens to a convex lens (step S9), or the function of the optical element LN as a convex lens is maintained (Yes in step S7).

[0148] Therefore, the eyeglasses 1A can be automatically switched between medium to long distance and close distance without the normal vision wearer HM having to operate the operation unit 19 and the operation device 200.

[0149] For example, when the line of sight of the myopic and hyperopic or myopic wearer HM is directed upward or horizontally above the horizontal plane, the optical element LN changes from a convex lens to a concave lens (step S13), or the function of the optical element LN as a concave lens is maintained (Yes in step S11). On the other hand, when the line of sight of the myopic and hyperopic or myopic wearer HM is directed downward below the horizontal plane, the optical element LN changes from a concave lens to a convex lens (step S9), or the function of the optical element LN as a convex lens is maintained (Yes in step S7).

[0150] Therefore, the wearer HM who is myopic and hyperopic or myopic can automatically switch the glasses 1A between for medium to long distances and for short distances without operating the operation unit 19 and the operation device 200. In addition, the second embodiment has the same effects as the first embodiment.

[0151] Furthermore, when a person looks at an object at close range, the line of sight tends to move inward from the neutral position. Furthermore, when a person looks at an object at medium to long distances, the line of sight tends to move outward from the neutral position. These tendencies can be utilized to control perspective. The "neutral position" refers to the position where the line of sight of one eye and the line of sight of the other eye of a person are approximately parallel and both lines of sight are directed straight ahead.

[0152] In addition, in step S9 of FIG. 11, the controller 55 may control the first power supply circuit PW1 and the second power supply circuit PW2 so that the difference value DFF indicates zero, and in step S13, the controller 55 may control the first power supply circuit PW1 and the second power supply circuit PW2 so that the difference value DFF indicates a positive value.

[0153] The glasses 1A may also have a head detection unit that detects the movement of the head of the wearer HM. Then, the control unit 17 may control the control voltage CV based on the detection result of the head detection unit to control the potential gradient of the liquid crystal layer 53. The head detection unit is, for example, an acceleration sensor and / or a gyro sensor.

[0154] The optical element LN may be applied to virtual reality (VR) glasses or augmented reality (AR) glasses. In this case, a complex lens movement mechanism or the like is not required, and focus control that always matches the eye characteristics of the wearer HM can be realized.

[0155] (Embodiment 3) A glasses system 100B according to a third embodiment of the present invention will be described with reference to Fig. 12 to Fig. 14. The glasses system 100B is mainly different from the glasses system 100 according to the first embodiment in that the light transmittance is controllable. The following mainly describes the differences between the third embodiment and the first embodiment.

[0156] FIG. 12 is a perspective view showing the glasses system 100B. As shown in FIG. 12, the glasses system 100B includes glasses 1B and an operation device 200. The glasses 1B further include an ambient light detection unit 77 in addition to the configuration of the glasses 1 according to the first embodiment. The ambient light detection unit 77 detects the brightness of the surrounding environment of the glasses 1B. The ambient light detection unit 77 is, for example, an ambient light sensor that detects the amount of light in the surrounding environment of the glasses 1B. The ambient light detection unit 77 is mounted on the frame F. Specifically, the ambient light detection unit 77 is installed on one of the pair of rims 3 (for example, the outer end of the one of the rims 3 relative to the bridge 5). The glasses 1B also include a pair of optical elements LNA instead of the pair of optical elements LN of the glasses 1 according to the first embodiment, a control unit 17B instead of the control unit 17 of the glasses 1, and an operation unit 19B instead of the operation unit 19 of the glasses 1. The optical element LNA functions as a lens.

[0157] Next, the optical element LNA will be described with reference to Fig. 13(a) and Fig. 13(b). Fig. 13(a) is a cross-sectional view of the optical element LNA taken along line XIII-XIII in Fig. 12. As shown in Fig. 13(a), the optical element LNA further includes a light-transmitting unit A3 capable of controlling light transmittance and a fourth substrate 36 in addition to the configuration of the optical element LN according to the first embodiment. The fourth substrate 36 has the same shape, material, and color as the first substrate 31. The light-transmitting unit A3 is disposed between the third substrate 35 and the fourth substrate 36. The first liquid crystal unit A1 faces the eye EY of the wearer HM via the first substrate 31.

[0158] FIG. 13(b) is a cross-sectional view showing the light-transmitting unit A3 shown in FIG. 13(a). As shown in FIG. 13(b), the light-transmitting unit A3 includes a fourth electrode E4, a light-transmitting layer 85, and a fifth electrode E5. A fourth voltage V4 is applied to the fourth electrode E4. The fourth voltage V4 is a DC voltage or an AC voltage. The fourth electrode E4 is planar and formed as a single layer. A fifth voltage V5 is applied to the fifth electrode E5. In the third embodiment, the fifth electrode E5 is grounded, and the fifth voltage V5 is set to a ground potential (0V). The fifth electrode E5 is planar and formed as a single layer.

[0159] The light transmitting layer 85 transmits light. The light transmittance of the light transmitting layer is controllable. The light transmittance indicates, for example, the ratio (=Ib / Ia) of the amount of light Ib emitted from the light transmitting layer 85 to the amount of light Ia incident on the light transmitting layer 85. The light transmitting layer 85 is disposed between the fourth electrode E4 and the fifth electrode E5.

[0160] The light transmitting layer 85 includes, for example, an electrochromic material. An electrochromic material is a material that can reversibly change the light transmittance by applying a voltage. Specifically, an electrochromic material is a material that reversibly changes the absorption spectrum of visible light by applying a voltage, causing coloring or decoloring.

[0161] The electrochromic material may be, for example, an inorganic electrochromic compound, an organic electrochromic compound, or a conductive polymer exhibiting electrochromism. Specifically, for example, the electrochromic material may be a dye-based, polymer-based, metal complex-based, or metal oxide-based electrochromic compound, or a carbon-based material.

[0162] Examples of the dye-based or polymer-based electrochromic compound include azobenzene-based, anthraquinone-based, diarylethene-based, dihydroprene-based, dipyridine-based, styryl-based, styrylspiropyran-based, spirooxazine-based, spirothiopyran-based, thioindigo-based, tetrathiafulvalene-based, terephthalic acid-based, triphenylmethane-based, triphenylamine-based, naphthopyran-based, viologen-based, pyrazoline-based, phenazine-based, phenylenediamine-based, phenoxazine-based, phenothiazine-based, phthalocyanine-based, fluoran-based, fulgide-based, benzopyran-based, or metallocene-based low molecular weight organic electrochromic compounds, or conductive polymer compounds such as polyaniline or polythiophene.

[0163] Examples of the metal complex-based compounds include iron cyano complexes, ruthenium cyano complexes, osmium cyano complexes, tungsten oxalate complexes, and rare earth diphthalocyanine complexes. Examples of the metal oxide-based compounds include tungsten oxide, molybdenum oxide, iridium oxide, indium oxide, titanium oxide, nickel oxide, and vanadium oxide. Examples of the carbon-based materials include functional graphene derivatives, conductive carbon materials such as carbon nanotubes, and other carbon allotropes.

[0164] Next, the operation of the glasses 1B will be described with reference to Fig. 14. Fig. 14 is a diagram showing the electrical configuration of the glasses system 100B. As shown in Fig. 14, the control unit 17B of the glasses 1B further includes a third power supply circuit PW3 in addition to the configuration of the control unit 17 according to the first embodiment. The operation unit 19B further includes a cutoff switch 87L and a cutoff switch 87R in addition to the configuration of the operation unit 19 according to the first embodiment.

[0165] The controller 55 controls the third power supply circuit PW3 in response to an internal operation signal from the operation unit 19B or an external operation signal from the operation device 200. Specifically, the processor 57 executes a computer program stored in the memory 59 to control the third power supply circuit PW3. Under the control of the controller 55, the third power supply circuit PW3 applies a fourth voltage V4 to the fourth electrode E4 of the light-transmitting unit A3. As a result, the fourth voltage V4 is applied to the light-transmitting layer 85 via the fourth electrode E4.

[0166] That is, the controller 55 controls the fourth voltage V4 via the third power supply circuit PW3 and applies the fourth voltage V4 to the light transmitting layer 85 via the fourth electrode E4 to control the light transmittance of the light transmitting layer 85. The light transmittance of the light transmitting layer 85 changes depending on the magnitude of the fourth voltage V4.

[0167] For example, when the wearer HM presses the cutoff switch 87L, the cutoff switch 87L transmits a third internal operation signal to the controller 55. When the wearer HM presses the cutoff switch 87L while the light transmittance of the light transmitting layer 85 is approximately zero percent, the cutoff switch 87L transmits a fourth internal operation signal to the controller 55. When the controller 55 receives the third internal operation signal or the fourth internal operation signal, the controller 55 starts to control the fourth voltage V4 applied to the fourth electrode E4 of one optical element LNA (hereinafter, may be referred to as the "optical element LNAL") of the pair of optical elements LNA. The cutoff switch 87R operates in the same manner as the cutoff switch 87L. However, when the cutoff switch 87R is pressed, the controller 55 starts to control the fourth voltage V4 applied to the fourth electrode E4 of the other optical element LNA (hereinafter, may be referred to as the "optical element LNAR").

[0168] For example, when the controller 55 receives the third internal operation signal from the cutoff switch 87L, it controls the fourth voltage V4 via the third power supply circuit PW3 so that the light transmittance of the light transmitting layer 85 of the optical element LNAL becomes a minimum value (e.g., approximately zero%). As a result, the light transmittance of the light transmitting layer 85 of the optical element LNAL is set to a minimum value (e.g., approximately zero%).

[0169] For example, when the controller 55 receives a fourth internal operation signal from the cutoff switch 87L, it controls the fourth voltage V4 via the third power supply circuit PW3 so that the light transmittance of the light transmitting layer 85 of the optical element LNAL becomes greater than approximately zero%. For example, when the controller 55 receives a fourth internal operation signal from the cutoff switch 87L, it controls the fourth voltage V4 via the third power supply circuit PW3 so that the light transmittance of the light transmitting layer 85 of the optical element LNAL becomes a maximum value (e.g., approximately 100%). For example, when the controller 55 receives a fourth internal operation signal from the cutoff switch 87L, it controls the fourth voltage V4 via the third power supply circuit PW3 so that the light transmittance of the light transmitting layer 85 of the optical element LNAL becomes the light transmittance before being set to approximately 0%.

[0170] Furthermore, the controller 55 controls the third power supply circuit PW3 based on the detection result of the ambient light detection unit 77 to control the fourth voltage V4 for each of the pair of optical elements LNA. As a result, the light transmittance of each of the light transmission layers 85 of the pair of optical elements LNA can be automatically controlled in accordance with the brightness of the environment surrounding the glasses 1B, without the wearer HM having to operate the operation unit 19B and the operation device 200. For example, the controller 55 controls the fourth voltage V4 so that the light transmittance of each of the light transmission layers 85 of the pair of optical elements LNA decreases as the environment surrounding the glasses 1B becomes brighter (i.e., as the amount of light in the environment increases).

[0171] As described above with reference to Fig. 13(a) and Fig. 13(b), according to the third embodiment, the light transmittance of the light transmitting layer 85 can be easily controlled by controlling the fourth voltage V4. That is, the light transmittance of the optical element LNA can be easily controlled. As a result, the glasses 1B can be used for various purposes.

[0172] For example, the glasses 1B can be applied to the treatment of amblyopia or strabismus. Specifically, when the wearer HM suffers from amblyopia or strabismus, the controller 55 controls the fourth voltage V4 so that the light transmittance of the light transmitting layer 85 of the optical element LNA corresponding to the normal eye of the pair of eyes becomes approximately zero percent. Therefore, the optical element LNA functions as an eye patch and can block light incident on the eye corresponding to the optical element LNA. As a result, it is useful for the treatment of amblyopia or strabismus. In addition, since it is not required to wear an eye patch, the inconvenience to the wearer HM can be reduced.

[0173] Furthermore, according to the third embodiment, the controller 55 can measure the time during which the light transmittance of the light transmitting layer 85 is approximately zero% (hereinafter, referred to as "eye patch function time") and store information about the eye patch function time. The controller 55 can then transmit the information about the eye patch function time to the operation device 200 via the terminals 23 and a5. The operation device 200 (specifically, the memory of the operation device 200) can store the information about the eye patch function time. Therefore, the wearer HM suffering from amblyopia or strabismus or a person related to the wearer HM (for example, a guardian or a medical professional) can easily manage the time during which the wearer HM has been treated for amblyopia or strabismus by the optical element LNA functioning as an eye patch.

[0174] Furthermore, according to the third embodiment, since the ambient light detection unit 77 is provided, the light transmittance of each light transmission layer 85 of the pair of optical elements LNA can be automatically controlled according to the brightness of the surrounding environment of the glasses 1B. That is, the amount of light incident on the eye of the wearer HM can be automatically controlled. As a result, the glasses 1B is not required to be operated, and the inconvenience of the wearer HM can be reduced. In particular, the glasses 1B are useful when the wearer HM suffers from photophobia. This is because the fourth voltage V4 is automatically controlled so that the light transmittance of the light transmission layer 85 decreases as the surrounding environment of the glasses 1B becomes brighter, without the wearer HM having to operate the operation unit 19B and the operation device 200.

[0175] Furthermore, according to the third embodiment, since there is no need to provide a polarizing plate, for example, the light transmittance of the optical element LNA can be increased to a maximum of 90% or more. In addition, the third embodiment has the same effects as the first embodiment.

[0176] The operation unit 19B may have a third switch and a fourth switch. For example, in response to pressing the third switch, the controller 55 controls the fourth voltage V4 via the third power supply circuit PW3 so that the light transmittance of the light transmitting layer 85 is increased. As a result, the light transmittance of the light transmitting layer 85 can be increased. For example, in response to pressing the fourth switch, the controller 55 controls the fourth voltage V4 via the third power supply circuit PW3 so that the light transmittance of the light transmitting layer 85 is decreased. As a result, the light transmittance of the light transmitting layer 85 can be decreased. For example, when the wearer HM suffers from photophobia, the wearer HM can manually adjust the light transmittance of the light transmitting layer 85 to suit himself / herself by operating the third switch or the fourth switch.

[0177] (Embodiment 4) A glasses system 100C according to a fourth embodiment of the present invention will be described with reference to Fig. 15 and Fig. 16. The glasses system 100C mainly differs from the glasses system 100 according to the first embodiment in that it detects pressure. Below, the differences between the fourth embodiment and the first embodiment will be mainly described.

[0178] Fig. 15 is a perspective view showing an eyewear system 100C. As shown in Fig. 15, the eyewear system 100C includes glasses 1C and an operation device 200. In addition to the configuration of the glasses 1 according to the first embodiment, the glasses 1C further include a first pressure detection unit 89 (pressure detection unit) and a pair of second pressure detection units 95 (a pair of pressure detection units).

[0179] The first pressure detection unit 89 detects pressure applied to the first pressure detection unit 89. The first pressure detection unit 89 is mounted on the frame F. Specifically, the first pressure detection unit 89 is installed on one of the pair of nose pads 15. More specifically, the first pressure detection unit 89 is installed on a surface of the one nose pad 15 that faces the other nose pad 15.

[0180] Therefore, when the wearer HM puts on the glasses 1C, the wearer HM's nose presses against the first pressure detection unit 89, and the first pressure detection unit 89 detects pressure. As a result, the detection of pressure by the first pressure detection unit 89 indicates that the wearer HM has put on the glasses 1C. On the other hand, when the wearer HM takes off the glasses 1C, the pressure of the wearer HM's nose against the first pressure detection unit 89 is released, and the first pressure detection unit 89 does not detect pressure. As a result, the absence of pressure detection by the first pressure detection unit 89 indicates that the wearer HM has taken off the glasses 1C.

[0181] Each of the second pressure detection units 95 detects pressure applied to the second pressure detection unit 95. The pair of second pressure detection units 95 are mounted on the frame F. Specifically, one of the pair of second pressure detection units 95 is installed on one of the pair of rims 3 (e.g., an upper part of one of the rims 3). The other second pressure detection unit 95 is installed on the other rim 3 (e.g., an upper part of the other rim 3).

[0182] Therefore, for example, when the wearer HM puts on the glasses 1C while wearing an eyepatch, the eyepatch presses against the second pressure detection unit 95, and the second pressure detection unit 95 detects pressure. As a result, the fact that the second pressure detection unit 95 has detected pressure indicates that the wearer HM has put on the glasses 1C while wearing the eyepatch. On the other hand, when the wearer HM removes the glasses 1C, the pressure of the eyepatch on the second pressure detection unit 95 is released, and the second pressure detection unit 95 does not detect pressure. As a result, the fact that the second pressure detection unit 95 does not detect pressure indicates that the wearer HM, who is wearing an eyepatch, has removed the glasses 1C.

[0183] Also, for example, when the first pressure detection unit 89 detects pressure and the second pressure detection unit 95 does not detect pressure, this indicates that the wearer HM is wearing the glasses 1C without wearing an eye patch.

[0184] Each of the first pressure detection unit 89 and the second pressure detection unit 95 is, for example, a pressure sensor. The pressure sensor detects pressure by, for example, a strain gauge resistance type, a semiconductor piezoresistance type, a capacitance type, or a silicon resonant type.

[0185] Next, the operation of the glasses 1C will be described with reference to Fig. 16. Fig. 16 is a diagram showing the electrical configuration of the glasses system 100C. As shown in Fig. 16, the control unit 17 of the glasses 1C measures and stores the time from when the first pressure detection unit 89 detects pressure to when it no longer detects pressure, that is, the time the glasses 1C are worn, based on the detection result of the first pressure detection unit 89. Also, the control unit 17 measures and stores the time from when the second pressure detection unit 95 detects pressure to when it no longer detects pressure, that is, the time the glasses 1C are worn while wearing an eye patch, based on the detection result of the second pressure detection unit 95.

[0186] Specifically, the controller 55 judges whether the level of the output signal from the first pressure detection unit 89 is equal to or greater than the first threshold. The controller 55 measures the time (hereinafter, referred to as "spectacles wearing time") from the time when it is judged that the level of the output signal from the first pressure detection unit 89 is equal to or greater than the first threshold to the time when it is judged that the level of the output signal from the first pressure detection unit 89 is less than the first threshold, and stores information on the eyeglasses wearing time. The judgement that the level of the output signal from the first pressure detection unit 89 is equal to or greater than the first threshold indicates that the first pressure detection unit 89 has detected pressure and the wearer HM has worn the eyeglasses 1C. On the other hand, the judgement that the level of the output signal from the first pressure detection unit 89 is less than the first threshold indicates that the first pressure detection unit 89 has not detected pressure and indicates that the wearer HM has removed the eyeglasses 1C. Furthermore, the controller 55 transmits information on the eyeglasses wearing time to the operation device 200 via the terminal 23 and the terminal a5. The operation device 200 (specifically, the memory of the operation device 200) stores information on the time the glasses are worn.

[0187] Therefore, according to embodiment 4, the wearer HM or a person related to the wearer HM can easily manage the time the wearer HM wears the glasses. For example, when the glasses 1C are used for treatment or vision training, the wearer HM or a person related to the wearer HM (e.g., a guardian or a medical professional) can easily manage the treatment time or vision training time based on the time the glasses are worn.

[0188] In addition to such training using the log recording function, training can be provided using short-distance wireless communication such as Bluetooth (registered trademark) between a smartphone application and the variable power glasses 1C. For example, an application for training weak eyesight can be installed on a smartphone, and training can be performed on the screen of the application. Furthermore, training can be provided in a system using a head-mounted display in combination with the above-mentioned virtual reality (VR) or augmented reality (AR) system. In this case, it may be used in combination with the glasses 1C, or only the optical element LN may be installed on the head-mounted display to share functions such as focus control, light deflection control, and light transmittance control.

[0189] Furthermore, by incorporating artificial intelligence into the application, a system can be provided that configures a program that proactively improves lifestyle habits. For example, the system can be urged to take action such as wearing glasses 1C voluntarily during treatment, detect eye fatigue and suggest taking a rest, or encourage the patient to move to a dark place if they have been in a bright place for too long.

[0190] The controller 55 also determines whether the level of the output signal from the second pressure detection unit 95 is equal to or greater than the second threshold. The controller 55 measures the time (hereinafter, referred to as "eyepatch wearing time") from the time when it is determined that the level of the output signal from the second pressure detection unit 95 is equal to or greater than the second threshold to the time when it is determined that the level of the output signal from the second pressure detection unit 95 is less than the second threshold, and stores information on the eyepatch wearing time. The determination that the level of the output signal from the second pressure detection unit 95 is equal to or greater than the second threshold indicates that the second pressure detection unit 95 has detected pressure, and the wearer HM has put on the glasses 1C while wearing the eyepatch. On the other hand, the determination that the level of the output signal from the second pressure detection unit 95 is less than the second threshold indicates that the second pressure detection unit 95 has not detected pressure, and indicates that the wearer HM wearing the eyepatch has removed the glasses 1C. Furthermore, the controller 55 transmits information on the eyepatch wearing time to the operating device 200 via the terminal 23 and the terminal a5. The operation device 200 (specifically, the memory of the operation device 200) stores information on the time the eyepatch was worn.

[0191] Therefore, according to embodiment 4, the wearer HM or a person related to the wearer HM can easily manage the time the wearer HM wears the eyepatch. For example, when the eyepatch is used to treat amblyopia or strabismus, the wearer HM or a person related to the wearer HM (e.g., a guardian or a medical professional) can easily manage the treatment time for amblyopia or strabismus with the eyepatch based on the time the eyepatch is worn. In addition, the fourth embodiment has the same effects as the first embodiment.

[0192] (Embodiment 5) A glasses system 100D according to a fifth embodiment of the present invention will be described with reference to Fig. 17 and Fig. 18. The glasses system 100D differs from the glasses system 100 according to the first embodiment mainly in that the glasses system 100D has a function of notifying the location of the glasses system 100D. The following mainly describes the differences between the fifth embodiment and the first embodiment.

[0193] Fig. 17 is a perspective view showing an eyewear system 100D. As shown in Fig. 17, the eyewear system 100D includes glasses 1D and an operation device 200D. In addition to the configuration of the glasses 1 according to the first embodiment, the glasses 1D further include a first notification unit 97 (notification unit) and a second notification unit 98 (notification unit).

[0194] Each of the first notification unit 97 and the second notification unit 98 notifies the location of the glasses 1D in response to a first predetermined signal FS (predetermined signal) transmitted wirelessly. Each of the first notification unit 97 and the second notification unit 98 is mounted on the frame F.

[0195] Specifically, the first notification unit 97 emits light in response to a first predetermined signal FS to notify the location of the glasses 1D. The first notification unit 97 is, for example, a light-emitting element such as an LED (Light Emitting Diode). The first notification unit 97 is installed on the bridge 5. The second notification unit 98 outputs sound in response to the first predetermined signal FS to notify the location of the glasses 1D. The second notification unit 98 is, for example, a speaker. The second notification unit 98 is installed on one of the pair of temples 11.

[0196] Moreover, the glasses 1D include a control unit 17D instead of the control unit 17 of the glasses 1 according to the first embodiment, and an operation unit 19D instead of the operation unit 19 of the glasses 1.

[0197] When the control unit 17D receives the first predetermined signal FS wirelessly transmitted by the operating device 200D, it controls the first notification unit 97 to emit light and controls the second notification unit 98 to output sound. As a result, the first notification unit 97 emits light and the second notification unit 98 outputs sound.

[0198] Therefore, according to the fifth embodiment, when the whereabouts of the glasses 1D are unknown, the owner of the glasses 1D can easily find out the whereabouts of the glasses 1D by operating the operating device 200D to transmit the first predetermined signal FS. As a result, the glasses 1D can be prevented from being lost. In addition, the fifth embodiment has the same effects as the first embodiment.

[0199] Next, the operation of the glasses 1D will be described with reference to Fig. 18. Fig. 18 is a diagram showing the electrical configuration of the glasses system 100D. As shown in Fig. 18, the control unit 17D of the glasses 1D further includes a GPS module 99 and a communicator 101 in addition to the configuration of the control unit 17 according to the first embodiment. The operation unit 19D further includes a search switch 102 in addition to the configuration of the operation unit 19 according to the first embodiment. Moreover, the operation device 200D further includes a communicator 103 in addition to the configuration of the operation device 200 according to the first embodiment.

[0200] The communication device 101 and the communication device 103 wirelessly communicate with each other. Then, the communication device 101 receives a first predetermined signal FS from the communication device 103. When the communication device 101 receives the first predetermined signal FS, the controller 55 controls the first notification unit 97 to emit light, and controls the second notification unit 98 to output sound. Therefore, the location of the glasses 1D can be easily known.

[0201] The GPS (Global Positioning System) module 99 detects the position of the glasses 1D and transmits the position information of the glasses 1D to the controller 55. When the communication device 101 receives the first predetermined signal FS, the controller 55 acquires the position information of the glasses 1D from the GPS module 99. Then, the controller 55 controls the communication device 101 to transmit the position information of the glasses 1D to the operation device 200D. As a result, the communication device 101 transmits the position information of the glasses 1D to the operation device 200D. The communication device 103 of the operation device 200D receives the position information of the glasses 1D. Then, the display a2 displays the position information of the glasses 1D.

[0202] Therefore, according to the fifth embodiment, when the whereabouts of the glasses 1D are unknown, the owner of the glasses 1D can easily check the location information of the glasses 1D by operating the operation device 200D to transmit the first predetermined signal FS. As a result, the loss of the glasses 1D can be further prevented.

[0203] For example, when the owner of the glasses 1D operates the operation key a3 of the operation device 200D, the communication device 103 transmits a first predetermined signal FS to the communication device 101.

[0204] The controller 55 controls the communicator 101 to transmit the second predetermined signal SS to the operation device 200D in response to an internal operation signal from the operation unit 19. As a result, the communicator 103 of the operation device 200D receives the second predetermined signal SS. When the communicator 103 receives the second predetermined signal SS, the display a2 emits light and the speaker a4 outputs sound.

[0205] Therefore, according to embodiment 5, when the location of the operating device 200D is unknown, the owner of the operating device 200D can easily find out the location of the operating device 200D by operating the operating unit 19D of the glasses 1D to transmit the second predetermined signal SS.

[0206] For example, when the owner of the operating device 200D presses the search switch 102, the search switch 102 transmits a fifth internal operation signal to the controller 55. Upon receiving the fifth internal operation signal, the controller 55 controls the communicator 101 to transmit a second predetermined signal SS to the operating device 200D.

[0207] (Embodiment 6) With reference to Fig. 1 and Fig. 19(a) to Fig. 22, an eyeglass system 100 according to a sixth embodiment of the present invention (hereinafter referred to as "eyeglass system 100E") will be described. Eyeglass system 100E differs from eyeglass system 100 according to the first embodiment mainly in that it deflects and emits light. Deflection of light refers to refracting a plurality of light beams having substantially the same angles of incidence at substantially the same refraction angles and emitting the light. Below, differences between embodiment 6 and embodiment 1 will be mainly described.

[0208] In the sixth embodiment, as shown in Fig. 1, the eyeglass system 100 will be replaced with an eyeglass system 100E. The eyeglass system 100E includes eyeglasses 1 (hereinafter, referred to as "glasses 1E") and an operation device 200. The eyeglasses 1E include a pair of optical elements LNB instead of the pair of optical elements LN of the eyeglasses 1 according to the first embodiment. The optical elements LNB function as deflection elements.

[0209] Fig. 19(a) is a plan view showing the optical element LNB. Fig. 19(b) is a schematic cross-sectional view of the optical element LNB taken along line XIXB-XIXB in Fig. 19(a). Fig. 19(b) shows a cross section taken along line II-II when the optical element LN in Fig. 1 is replaced with the optical element LNB.

[0210] 19(a) and 19(b), optical element LNB further includes an optical member PM having a sawtooth cross section in addition to the configuration of optical element LN according to embodiment 1. Optical element LNB also includes a first liquid crystal unit B1 instead of the first liquid crystal unit A1 according to embodiment 1, and includes a second liquid crystal unit B2 instead of the second liquid crystal unit A2 according to embodiment 1. The first liquid crystal unit B1 includes a liquid crystal layer 53 (hereinafter may be referred to as "liquid crystal layer 53A"), and the second liquid crystal unit B2 includes a liquid crystal layer 53 (hereinafter may be referred to as "liquid crystal layer 53B").

[0211] The optical member PM deflects light. In other words, the optical member PM refracts a plurality of light beams having substantially the same incident angles at substantially the same refraction angles and emits the light. The optical member PM is disposed on the first substrate 31. Therefore, the optical member PM faces the first liquid crystal unit B1 via the first substrate 31. The optical member PM is, for example, a glass prism having a sawtooth cross section.

[0212] Specifically, the optical member PM includes a plurality of optical elements 84. The plurality of optical elements 84 refract light at the same refraction angle. For example, each of the optical elements 84 refracts light LT perpendicularly incident on the optical element LNB at a first refraction angle θF. As a result, the optical member PM deflects light. The first refraction angle θF indicates the angle of light emitted from the optical element 84 with respect to light incident on the optical element 84. The plurality of optical elements 84 are arranged approximately parallel to each other. Each of the optical elements 84 has a triangular prism shape. Therefore, each of the optical elements 84 has a triangular shape in cross section (for example, a right-angled triangular shape in cross section).

[0213] For example, a wearer HM has a squinting eye EY, and the eye EY faces the second liquid crystal unit B2 via the third substrate 35. The optical member PM deflects the light LT. Furthermore, the first liquid crystal unit B1 and the second liquid crystal unit B2 deflect and emit the light LT deflected by the optical member PM. The light LT then enters the eye EY. According to the sixth embodiment, the light LT can be deflected to enter the squinting eye EY, so that the object seen by the other normal eye can be easily seen by the squinting eye EY. Therefore, the wearer HM can be encouraged to use the squinting eye EY. As a result, the glasses 1E are effective for correcting or improving strabismus.

[0214] In FIG. 19(b), for the sake of simplicity, the deflection by the first liquid crystal unit B1 and the second liquid crystal unit B2 is not reflected in the light LT.

[0215] Here, the liquid crystal layer 53 of the first liquid crystal unit B1 and the second liquid crystal unit B2 deflects light, which differs from the liquid crystal layer 53 of the first liquid crystal unit A1 and the second liquid crystal unit A2 according to embodiment 1 which converges or diverges light. That is, in embodiment 6, the liquid crystal layer 53 functions as a deflection element, and refracts a plurality of light beams having substantially the same angles of incidence at substantially the same refraction angles and emits them.

[0216] Therefore, the potential gradient formed in the liquid crystal layer 53 of the first liquid crystal unit B1 and the second liquid crystal unit B2 is different from the potential gradient formed in the liquid crystal layer 53 of the first liquid crystal unit A1 and the second liquid crystal unit A2 according to the first embodiment.

[0217] 1, 19(b), and 19(c), the potential gradient Q1 formed in the liquid crystal layer 53 according to embodiment 6 will be described. FIG. 19(c) is a diagram showing the potential gradient Q1 in the liquid crystal layer 53.

[0218] 1, 19(b), and 19(c), the control unit 17 applies a control voltage CV to each of the liquid crystal layers 53A and 53B to form a sawtooth-shaped potential gradient Q1 in each of the liquid crystal layers 53A and 53B, thereby controlling the refraction of light (deflection of light in the sixth embodiment). The control voltage CV is common to the liquid crystal layers 53A and 53B. Therefore, similar to the first embodiment, the potential gradient Q1 formed in the liquid crystal layer 53A is substantially the same as the potential gradient Q1 formed in the liquid crystal layer 53B.

[0219] Specifically, the potential gradient Q1 includes a plurality of potential gradients Q2. That is, a linear, smooth potential gradient Q2 is formed in the liquid crystal layer 53 in the direction D1. The smooth potential gradient Q2 refers to a potential gradient that is not stepped.

[0220] For ease of understanding, the refraction of light LTa perpendicularly incident on the liquid crystal layer 53 will be described below. As shown in FIG. 19(c), the liquid crystal layer 53 refracts (specifically, polarizes) the light LTa at a second refraction angle θS according to the gradient angle α of the potential gradient Q2. The second refraction angle θS indicates the angle of the light emitted from the liquid crystal layer 53 with respect to the light incident on the liquid crystal layer 53. In the sixth embodiment, the second refraction angle θS is smaller than the first refraction angle θF. The liquid crystal layer 53 refracts (specifically, deflects) the light refracted (specifically, deflected) by the optical member PM and emits it.

[0221] Next, the first liquid crystal unit B1 will be described with reference to Figures 20 and 21. Below, the differences between the first liquid crystal unit B1 and the first liquid crystal unit A1 will be mainly described. The configuration of the second liquid crystal unit B2 is the same as the configuration of the first liquid crystal unit B1.

[0222] Fig. 20 is a plan view showing the first liquid crystal unit B1. Fig. 21 is a cross-sectional view of the first liquid crystal unit B1 taken along line XXI-XXI in Fig. 20. For ease of understanding, Fig. 21 illustrates the optical member PM, the first substrate 31, and the second substrate 33.

[0223] 20 and 21, the first liquid crystal unit B1 includes a plurality of unit electrodes 10, an insulating layer 51, a plurality of first boundary layers 61, a plurality of second boundary layers 62, a plurality of high resistance layers 52 (a plurality of resistance layers), a liquid crystal layer 53, and a third electrode E3. Each of the unit electrodes 10 includes a first electrode E1 and a second electrode E2.

[0224] The unit electrodes 10 extend substantially parallel to one another. The extension direction of the unit electrodes 10 is substantially parallel to the extension direction of the optical elements 84. One unit electrode 10 is disposed corresponding to one optical element 84, and faces one optical element 84 with the first substrate 31 interposed therebetween.

[0225] The unit electrodes 10 are arranged in the same layer. Among the unit electrodes 10 adjacent to each other, the second electrode E2 of one unit electrode 10 is adjacent to the first electrode E1 of the other unit electrode 10. The first electrode E1 and the second electrode E2 extend approximately parallel to each other.

[0226] The first electrode E1 and the second electrode E2 constitute a unit electrode 10 and are arranged in the same layer. In each of the unit electrodes 10, the first electrode E1 and the second electrode E2 face each other via an insulating layer 51 and are linearly shaped extending side by side with a gap W1 therebetween. In each of the unit electrodes 10, the gap W1 between the first electrode E1 and the second electrode E2 is larger than the width K1 of the first electrode E1 and larger than the width K2 of the second electrode E2. However, the gap W1 can be set to any size. The gap W1 indicates the distance between the inner edge of the first electrode E1 and the inner edge of the second electrode E2. In addition, the lengths of the first electrode E1 and the second electrode E2 can be set to any size.

[0227] Furthermore, width K1 indicates the width of the first electrode E1 along the direction D1. Width K2 indicates the width of the second electrode E2 along the direction D1. The direction D1 is a direction from the first electrode E1 to the second electrode E2, is approximately perpendicular to the longitudinal directions of the first electrode E1 and the second electrode E2, and is approximately parallel to the liquid crystal layer 53.

[0228] A first voltage V1 is applied to the first electrode E1. A second voltage V2 is applied to the second electrode E2. The first voltage V1 and the second voltage V2 may be the same or different. A third voltage V3 is applied to the third electrode E3. In the sixth embodiment, the third electrode E3 is grounded, and the third voltage V3 is set to the ground potential (0V). The unit electrode 10 is farther from the eye than the liquid crystal layer 53.

[0229] The insulating layer 51 has a thickness ts. The thickness ts indicates the thickness of a portion of the insulating layer 51 located between the first electrode E1 and the high resistance layer 52, or the thickness of a portion of the insulating layer 51 located between the second electrode E2 and the high resistance layer 52. The liquid crystal layer 53 is disposed between the unit electrode 10 and the third electrode E3.

[0230] The electrical resistivity (specific resistance) of the high-resistance layer 52 is greater than the electrical resistivity of the first electrode E1 and the electrical resistivity of the second electrode E2, and is smaller than the electrical resistivity of the insulating layer 51. The high-resistance layer 52 has a thickness th. The thickness ts of the insulating layer 51 is smaller than the thickness th of the high-resistance layer 52. The smaller the thickness ts of the insulating layer 51, the better, as long as insulation between the first electrode E1 and the second electrode E2 and the high-resistance layer 52 is maintained.

[0231] 21, the potential gradient Q1 of the liquid crystal layer 53 will be described. In FIG. 21, the potential gradient Q1 is shown when the first voltage V1 is smaller than the second voltage V2. Each of the potential gradients Q2 changes continuously from below the first electrode E1 to below the second electrode E2 without having any extreme values ​​(minimum and maximum values). In addition, in the region of the liquid crystal layer 53 facing the second boundary layer 62, the potential drops sharply.

[0232] The optical element 84 is inclined at an acute angle with respect to the direction D1. When the first voltage V1 is smaller than the second voltage V2, each of the potential gradients Q2 is inclined at an acute angle with respect to the direction D1, similar to the optical element 84. That is, the inclination direction of the optical element 84 and the inclination direction of the potential gradient Q2 are aligned. When the first voltage V1 is smaller than the second voltage V2, the liquid crystal layer 53 refracts the light refracted by the optical member PM toward the side where the optical member PM refracts the light. For convenience of explanation, the sign of the second refraction angle θS (FIG. 19(c)) in this case is set to "positive (plus)". When the first voltage V1 is smaller than the second voltage V2, the gradient angle α (FIG. 19(c)) of the potential gradient Q2 is determined with respect to the direction D1.

[0233] On the other hand, when the first voltage V1 is greater than the second voltage V2, each of the potential gradients Q2 is inclined at an acute angle with respect to the direction D2. That is, the inclination direction of the optical element 84 and the inclination direction of the potential gradient Q2 are opposite to each other. The direction D2 indicates the opposite direction to the direction D1. In this case, the potential gradient Q2 has a shape obtained by left-right inverting the potential gradient Q2 shown in FIG. 21. Also, when the first voltage V1 is greater than the second voltage V2, the liquid crystal layer 53 refracts the light refracted by the optical member PM to the side opposite to the side where the optical member PM refracts the light. For convenience of explanation, the sign of the second refraction angle θS in this case is set to "negative (minus)". Note that, when the first voltage V1 is greater than the second voltage V2, the gradient angle α of the potential gradient Q2 is determined with respect to the direction D2.

[0234] Moreover, the gradient angle α of the potential gradient Q2 changes according to the magnitude of the difference value DFF (=V1-V2) between the first voltage V1 and the second voltage V2. Specifically, the larger the difference value DFF, the larger the gradient angle α becomes, and the larger the absolute value of the second refraction angle θS becomes. Furthermore, when the difference value DFF is zero, the liquid crystal layer 53 loses its function as a deflection element, and light that is perpendicularly incident on the liquid crystal layer 53 travels straight. For example, the first refraction angle θF is 15 degrees, and the second refraction angle θS can be changed in the range from minus 2 degrees to plus 2 degrees by controlling the difference value DFF. Therefore, in this example, the light deflection angle of the optical element LNB can be changed in the range from 13 degrees to 17 degrees.

[0235] Furthermore, a potential gradient surface is formed in the liquid crystal layer 53 along the longitudinal direction of the first electrode E1 and the second electrode E2. The potential gradient surface is a surface formed by a potential gradient Q2 that continues along the longitudinal direction of the first electrode E1 and the second electrode E2. Therefore, the incident light can be refracted and emitted so that the second refraction angle θS is approximately the same in the longitudinal direction of the first electrode E1 and the second electrode E2.

[0236] Next, the operation of the glasses 1E will be described with reference to Fig. 22. Fig. 22 is a diagram showing the electrical configuration of the glasses system 100E. As shown in Fig. 22, the configuration of the glasses 1E is similar to the configuration of the glasses 1 according to the first embodiment. However, the glasses 1E do not have the core electrode 50, the center electrode rc, the first lead wire 71, the second lead wire 72, and the third boundary layer 73 according to the first embodiment.

[0237] The first power supply circuit PW1 applies a first voltage V1 to the first electrodes E1 of each of the first liquid crystal unit B1 and the second liquid crystal unit B2 under the control of the controller 55. The first voltage V1 is an example of a control voltage CV.

[0238] The second power supply circuit PW2 applies a second voltage V2 to the second electrodes E2 of each of the first liquid crystal unit A1 and the second liquid crystal unit A2 under the control of the controller 55. The second voltage V2 is an example of a control voltage CV.

[0239] The controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 in response to an internal operation signal from the operation unit 19 or an external operation signal from the operation device 200 to control the first voltage V1 and the second voltage V2. The control of the first voltage V1 and the second voltage V2 can control the potential gradient of the liquid crystal layer 53. Specifically, the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 to control the difference value DFF (=V1-V2) between the first voltage V1 and the second voltage V2. The control of the difference value DFF can control the potential gradient of the liquid crystal layer 53. As a result, the second refraction angle θS can be changed from a negative value to a positive value. In addition, the second refraction angle θS can be set to zero degrees by setting the difference value DFF (specifically, the difference value DV) to zero.

[0240] More specifically, when the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the voltage value v1 of the first voltage V1 is smaller than the voltage value v2 of the second voltage V2, a potential gradient Q1 having a sawtooth cross section is formed in the liquid crystal layer 53. The potential gradient Q1 includes a plurality of potential gradients Q2 that are inclined at acute angles with respect to the direction D1.

[0241] When a plurality of potential gradients Q2 inclined at an acute angle with respect to the direction D1 are formed, the liquid crystal layer 53 refracts the light refracted by the optical member PM in the direction in which the optical member PM refracts the light.

[0242] On the other hand, when the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the voltage value v1 of the first voltage V1 is greater than the voltage value v2 of the second voltage V2, a potential gradient Q1 having a sawtooth cross section is formed in the liquid crystal layer 53. The potential gradient Q1 includes a plurality of potential gradients Q2 that are inclined at acute angles with respect to the direction D2.

[0243] When a plurality of potential gradients Q2 inclined at an acute angle with respect to the direction D2 are formed, the liquid crystal layer 53 refracts the light refracted by the optical member PM in a direction opposite to the side where the optical member PM refracts the light.

[0244] In addition, the greater the absolute value of the difference value DV (=v1-v2) between the voltage value v1 of the first voltage V1 and the voltage value v2 of the second voltage V2, the greater the absolute value of the second refraction angle θS. When the voltage values ​​v1 and v2 are different, the greater the absolute value of the difference value DF (=f1-f2) between the frequency f1 of the first voltage V1 and the frequency f2 of the second voltage V2, the greater the absolute value of the second refraction angle θS.

[0245] Furthermore, when the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the voltage value v1 and the voltage value v2 are the same and the frequency f1 and the frequency f2 are the same, the liquid crystal layer 53 loses its function as a deflection element.

[0246] For example, when the wearer HM presses the first switch 65, the first switch 65 transmits a sixth internal operation signal to the controller 55. Upon receiving the sixth internal operation signal, the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the absolute value of the difference value DFF (e.g., the difference value DV) increases. As a result, the absolute value of the second refraction angle θS increases.

[0247] On the other hand, for example, when the wearer HM presses the second switch 67, the second switch 67 transmits a seventh internal operation signal to the controller 55. Upon receiving the seventh internal operation signal, the controller 55 controls the first power supply circuit PW1 and the second power supply circuit PW2 so that the absolute value of the difference value DFF (for example, the difference value DV) decreases. As a result, the absolute value of the second refraction angle θS decreases.

[0248] As described above with reference to FIG. 19(b), according to the sixth embodiment, the optical element LNB has the optical member PM, and therefore the glasses 1E are effective for correcting or improving strabismus.

[0249] In addition, as described with reference to Figs. 21 and 22, according to the sixth embodiment, the potential gradient of the liquid crystal layer 53 can be easily controlled by controlling the control voltage CV (specifically, the first voltage V1 and the second voltage V2). Therefore, the second refraction angle θS can be easily changed over a relatively wide range from negative values ​​to positive values ​​by controlling the control voltage CV. As a result, when the degree of strabismus of the wearer HM changes (for example, when the strabismus is improved), the second refraction angle θS can be adjusted to match the "strabismus eye after the change" and light can be incident on the "strabismus eye after the change" without replacing the optical element LNB and the glasses 1E.

[0250] In addition, the sixth embodiment has the same effects as the first embodiment, except for the convex lens function and the concave lens function.

[0251] Furthermore, according to the sixth embodiment, it is possible to assist the eyesight of patients with a condition called "nystagmus," in which the eyes vibrate, and to perform training for treatment. Specifically, the voltage is controlled so that the incident light is tilted in a direction that tracks the vibration of the patient's eyeball in accordance with the frequency of the vibration of the patient's eyeball (for example, 2 Hz to 3 Hz) and cancels the blurring of the image caused by the nystagmus. As a result, even if the patient shows symptoms of nystagmus, the patient can always recognize an image without vibration, and it is possible to support the normal development of the eye.

[0252] The embodiments and examples of the present invention have been described above with reference to the drawings (FIGS. 1 to 22). However, the present invention is not limited to the above embodiments and examples, and can be implemented in various aspects without departing from the gist of the present invention (for example, (1) to (5) shown below). The drawings are mainly schematic illustrations of each component for ease of understanding, and the thickness, length, number, etc. of each component shown in the drawings may differ from the actual ones due to the convenience of drawing. Furthermore, the shape, dimensions, etc. of each component shown in the above embodiments are merely examples and are not particularly limited, and various modifications are possible without substantially departing from the effects of the present invention.

[0253] (1) The features of the eyeglass systems 100 to 100E according to the first to sixth embodiments may be combined in any desired manner to configure an eyeglass system. For example, the eye detection unit 75 shown in FIG. 10 may be provided in the eyeglasses 1B to 1D according to the third to fifth embodiments to control the focal length according to the line of sight of the wearer HM as in the second embodiment. For example, the optical element LNA, the operation unit 19B, and the ambient light detection unit 77 shown in FIG. 14 may be provided in the eyeglasses 1C and 1C according to the fourth and fifth embodiments to control the light transmittance as in the third embodiment. For example, the first pressure detection unit 89 and the second pressure detection unit 95 shown in FIG. 16 may be provided in the eyeglasses 1D and 1E according to the fifth and sixth embodiments to detect pressure as in the fourth embodiment. For example, the control unit 17D, operation unit 19D, first notification unit 97, and second notification unit 98 shown in FIG. 18 may be provided in the glasses 1E of embodiment 6, and the operation device 200D shown in FIG. 18 may be provided in the glasses system 100E of embodiment 6 to provide a function of notifying the location, similar to embodiment 5.

[0254] For example, the eye detection unit 75 shown in Fig. 10 may be provided in the glasses 1E of embodiment 6. Then, the control unit 17 controls the control voltage CV of the liquid crystal layer 53 based on the line of sight direction SLL and / or the line of sight direction SLR to control the second refraction angle θS. For example, the control unit 17 controls the control voltage CV of the liquid crystal layer 53 to change the second refraction angle θS in response to changes in the line of sight direction SLL and / or the line of sight direction SLR.

[0255] For example, the first liquid crystal unit A1 and the second liquid crystal unit A2 shown in Fig. 2 may be added to the configuration of the optical element LNB shown in Fig. 19, and the control unit 17 may control the focal length of the optical element LNB as in embodiment 1. For example, the light-transmitting unit A3 shown in Fig. 13(a) may be added to the configuration of the optical element LNB shown in Fig. 19, and the control unit 17 may control the light transmittance of the optical element LNB as in embodiment 3. For example, the first liquid crystal unit A1 and the second liquid crystal unit A2 shown in Fig. 2 and the light-transmitting unit A3 shown in Fig. 13(a) may be added to the configuration of the optical element LNB shown in Fig. 19.

[0256] (2) In the first to sixth embodiments, a pair of optical elements LN, a pair of optical elements LNA, and a pair of optical elements LNB are provided, but one optical element LN, one optical element LNA, and one optical element LNB may be provided. One of the first liquid crystal unit A1 and the second liquid crystal unit A2 may be provided, or one of the first liquid crystal unit B1 and the second liquid crystal unit B2 may be provided. In the second embodiment, one eye detection unit 75 may be provided. In the fourth embodiment, one of the first pressure detection unit 89 and the second pressure detection unit 95 may be provided. One second pressure detection unit 95 may be provided. In the fifth embodiment, one of the first notification unit 97 and the second notification unit 98 may be provided.

[0257] In addition, in the first to sixth embodiments, the control voltage CV may be controlled separately for each optical element LN, for each optical element LNA, or for each optical element LNB.

[0258] (3) In the first to sixth embodiments, the number of unit electrodes rn and the number of unit electrodes 10 are not particularly limited. The control voltage CV may be controlled for each unit electrode rn or for each unit electrode 10. The control voltage CV may be different between the unit electrode rn and the core electrode 50 and the center electrode rc. In the first to fifth embodiments, the core electrode 50 may not be provided. In particular, when the optical element LN and the optical element LNA are not made to function as concave lenses, the core electrode 50 may not be provided. When the core electrode 50 is not provided, the center electrode rc and the unit electrodes rn are arranged in a concentric shape with the center electrode rc as the center. In addition, the first lead wire 71, the second lead wire 72, and the third boundary layer 73 may not be provided. In this case, a plurality of through holes are formed to apply the first voltage V1 and the second voltage V2. When the through holes are formed, each of the center electrode rc, the first electrode E1, and the second electrode E2 has an uninterrupted annular shape.

[0259] (4) In the first to sixth embodiments, the insulating layer 51 may not be provided. The thickness ts of the insulating layer 51 may be the same as the thickness th of the high resistance layer 52, or may be greater than the thickness th of the high resistance layer 52. In the first to sixth embodiments, the high resistance layer 52 is disposed between the liquid crystal layer 53 and the unit electrode rn (or the unit electrode 10), and the high resistance layer 52 is disposed between the liquid crystal layer 53 and the core electrode 50 and the center electrode rc. However, the unit electrode rn (or the unit electrode 10) may be disposed between the high resistance layer 52 and the liquid crystal layer 53, and the core electrode 50 and the center electrode rc may be disposed between the high resistance layer 52 and the liquid crystal layer 53.

[0260] (5) In this specification and claims, the term "linear" includes a strictly linear shape as well as an approximately linear shape. The term "annular" includes a strictly annular shape as well as an approximately annular shape. The term "annular shape" includes an uninterrupted annular shape as well as a partially interrupted annular shape. The term "concentric" includes a strictly concentric shape as well as an approximately concentric shape. The term "planar" includes a strictly planar shape as well as an approximately planar shape. The term "serrated" includes a strictly sawtooth shape as well as an approximately sawtooth shape. The term "annular" includes a strictly annular shape as well as an approximately annular shape. The term "band" includes a strictly band shape as well as an approximately band shape. The term "curved" includes a strictly curved shape as well as an approximately curved shape. The term "flat" includes a strictly flat plate as well as an approximately flat plate shape. The term "disk" includes a strictly disk as well as an approximately disk shape. The term "triangular" includes a strictly triangular shape as well as an approximately triangular shape. The triangular prism shape includes not only a strict triangular prism but also an approximate triangular prism shape. [Industrial Applicability]

[0261] INDUSTRIAL APPLICABILITY The present invention provides eyeglasses and optical elements, and has industrial applicability. [Explanation of symbols]

[0262] 1, 1A~1E Glasses 17 Control Unit 53 Liquid crystal layer 75 Eye detection unit 85 Light transmission layer 89 First pressure detection unit (pressure detection unit) 95 Second pressure detection unit (pressure detection unit) 97 First Notification Unit (Notification Unit) 98 Second Notification Unit (Notification Unit) LN, LNA, LNB optical elements PM Optical Components

Claims

1. A first liquid crystal unit; a second liquid crystal unit disposed on the first liquid crystal unit; Equipped with Each of the first liquid crystal unit and the second liquid crystal unit is A liquid crystal layer; a first electrode and a second electrode each having an annular shape; a resistive layer having an electrical resistivity greater than the electrical resistivity of the first electrode and the second electrode and less than the electrical resistivity of an electrical insulator, the resistive layer being disposed between the first electrode and the second electrode in a plan view; Equipped with an alignment direction of the liquid crystal of the liquid crystal layer of the first liquid crystal unit and an alignment direction of the liquid crystal of the liquid crystal layer of the second liquid crystal unit are substantially perpendicular to each other; Optical elements.

2. The optical element according to claim 1 ; A control unit that controls a voltage applied to the optical element; Glasses equipped with

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