JP2021085924A - Optical apparatus and optical element - Google Patents

Abstract

To provide an optical apparatus with which it is possible to realize good visibility in an intermediate region and in a distant region.SOLUTION: The optical apparatus comprises: an optical element including a liquid crystal layer 6 provided between a plurality of zonal electrodes 1-4 and an electrode layer 5; and a control unit for causing the optical element to change between an electrically activated state and an electrically deactivated state. The plurality of zonal electrodes include a first zonal electrode 1 to a fourth zonal electrode 4, and the electrically activated state includes a first state in which the optical element has first optical power and a second state in which the optical element has second optical power smaller than the first optical power, with a first voltage applied to the first zonal electrode 1 in the first and second states, a second voltage higher than the first voltage applied to a second zonal electrode 2 in the first and second states, the first voltage applied to a third zonal electrode 3 in the first state and a third voltage higher than the first voltage applied in the second state, the second voltage applied to the fourth zonal electrode 4 in the first state and a fourth voltage higher than the second voltage applied in the second state.SELECTED DRAWING: Figure 6

Description

The present invention relates to optical instruments and optical elements.

Patent Document 1 describes electricity capable of applying optical power to the presbyopia power section when the user looks at a distant region, and does not add optical power to the presbyopia power section when looking at a near region. The active element (liquid crystal lens) is disclosed.

Special Table 2011-516927

The liquid crystal lens of Patent Document 1 is configured by arranging a variable power region in a part of a progressive power lens whose curvature changes smoothly. Therefore, in the electrically inactivated state, when the user looks at a distant region, the scenery looks distorted, which is not preferable. If a variable power region is arranged in a part of a fixed power lens having a constant curvature in order to solve such a problem, it becomes impossible to focus on the intermediate region, which is not preferable.

An object of the present invention is to provide an optical device and an optical element capable of achieving good visibility in an intermediate region and a distant region.

The optical device as one aspect of the present invention is provided between a plurality of annular electrodes arranged concentrically, an electrode layer facing the plurality of annular electrodes, and the plurality of annular electrodes and the electrode layer. It has an optical element including a liquid crystal layer and a control unit that changes the optical element into an electrically activated state and an electrically inactivated state. The electrically activated state includes a ring-shaped electrode, a third ring-shaped electrode, and a fourth ring-shaped electrode, and the electrically activated state is a first state in which the optical element has a first optical power, and a first optical power. A second state with a smaller second optical power is included, the first annulus electrode is subjected to a first voltage in the first and second states, and the second annulus electrode is subjected to a first voltage. , A second voltage higher than the first voltage is applied in the first and second states, and the first voltage is applied to the third annulus electrode in the first state, and in the second state. A third voltage higher than the first voltage is applied, and a second voltage is applied to the fourth annulus electrode in the first state, and a fourth voltage lower than the second voltage in the second state. It is characterized in that a voltage is applied.

Further, the optical element as another aspect of the present invention is an optical element that changes between an electrically activated state and an electrically inactivated state, and includes a plurality of annular electrodes arranged concentrically and a plurality of rings. An electrode layer facing the band electrode, a liquid crystal layer provided between the plurality of ring band electrodes and the electrode layer, a resistance layer provided between the plurality of ring band electrodes and the liquid crystal layer, and a plurality of ring band electrodes. It has an insulating layer provided between the and a resistance layer, and the electrically activated state is a first state in which the optical element has a first optical power, and a second state smaller than the first optical power. When the surface resistance of the resistance layer is R1 and the surface resistance of the insulating layer is R2, including the second state having optical power,
1 × 10 ^-5 <R1 / R2 <1 × 10 ^-2
It is characterized in that it satisfies the conditional expression.

According to the present invention, it is possible to provide an optical device and an optical element capable of achieving good visibility in an intermediate region and a distant region.

It is a perspective view of the electronic eyeglass which is an example of the optical device which concerns on embodiment of this invention. It is a front view of the electronic eyeglasses. It is a block diagram of an electronic eyeglass. It is a front view of an electrically activated lens. It is a figure which shows the cross-sectional view of the variable power region and the optical phase difference distribution in the 1st state. It is a figure which shows the cross-sectional view of the variable power region and the optical phase difference distribution in the second state. It is explanatory drawing of the control method of the variable power region in the 1st state. It is explanatory drawing of the control method of the variable power region in a 2nd state. It is explanatory drawing of the manufacturing method of a plurality of annulus electrodes. It is a figure which shows the orientation distribution of the liquid crystal molecule in the 1st state of Example 1. FIG. It is a figure which shows the optical retardation distribution which occurs in the liquid crystal layer in the 1st state of Example 1. FIG. It is a figure which shows the orientation distribution of the liquid crystal molecule in the 2nd state of Example 1. FIG. It is a figure which showed the optical retardation distribution which occurs in the liquid crystal layer in the 2nd state of Example 1. FIG. It is a figure which shows the orientation distribution of the liquid crystal molecule in the 1st state of Example 2. FIG. It is a figure which shows the optical retardation distribution which occurs in the liquid crystal layer in the 1st state of Example 2. FIG. It is a figure which shows the orientation distribution of the liquid crystal molecule in the 2nd state of Example 2. FIG. It is a figure which shows the optical retardation distribution which occurs in the liquid crystal layer in the 2nd state of Example 2. FIG. It is a figure which shows the potential distribution of the liquid crystal layer in the 1st state of Example 3. FIG. It is a figure which shows the optical phase difference distribution obtained from the potential distribution of FIG. It is a figure which shows the potential distribution of the liquid crystal layer of the comparative example. It is a figure which shows the potential distribution of the liquid crystal layer of the comparative example.

Hereinafter, examples of the present invention will be described in detail with reference to the drawings. In each figure, the same member is given the same reference number, and duplicate description is omitted.

FIG. 1 is a perspective view of an electronic eyeglass 10 which is an example of an optical device according to an embodiment of the present invention. FIG. 2 is a front view of the electronic eyeglasses 10. FIG. 3 is a block diagram of the electronic eyeglasses 10.

The electronic spectacles 10 have electrically activated lenses (optical elements) 11, 12, frames 13, and temples 14, 15. The electrically active lenses 11 and 12 are liquid crystal lenses having a variable focus function. The electrically activated lens 11 is for the right eye and has a variable power region 101. The electrically activated lens 12 is for the left eye and has a variable power region 102. The frame 13 holds the electrically activated lenses 11 and 12 and has a cable 16 internally connected to the electrically activated lenses 11 and 12. The temples 14 and 15 are connected to the frame 13 and have sensor units 21 and 22, controller units (control units) 31 and 32, and power supply units 41 and 42 inside. The sensor units 21 and 22, the controller units 31 and 32, and the power supply units 41 and 42 are electrically connected to the cable 16. The controller units 31 and 32 control the voltage applied to the electrically active lenses 11 and 12, respectively, in response to the signals from the sensor units 21 and 22, respectively. By controlling the voltage applied to the electrically active lenses 11 and 12 by the controller units 31 and 32, it is possible to change the optical state of the electrically active lenses 11 and 12 (variable power regions 101 and 102). Here, the optical state means the optical power (focal length) of the variable power regions 101 and 102.

In each electrically activated lens, each variable power region has an optical state in which no optical power is substantially applied (electrically inactivated state) and an optical state in which the optical power is applied (electrically activated state). And can be switched. For example, each variable power region has substantially no optical power in the electrically inactivated state and has the desired optical power (eg + 2D) in the electrically activated state. Therefore, in the electronic eyeglasses 10, the optical power may not be added to each variable power region when looking at the distant region, and the optical power may be added to each variable power region when looking at the near region. As a result, in the electrically inactivated state, the regions having different optical powers do not exist in the electrically active lenses 11 and 12, and a uniform power distribution can be obtained. That is, in the electrically inactivated state, the electronic glasses 10 (electrically activated lenses 11 and 12) with little distortion and good visibility can be realized.

Further, in each electrically activated lens, in the electrically activated state, each variable power region has a first state having a first optical power and a second optical power smaller than the first optical power. It is possible to switch between the states of. For example, each variable power region has, for example, + 2D in the first state and, for example, + 1D in the second state. In the present embodiment, the second optical power is set to be substantially equal to a value of 1/2 of the first optical power. Specifically, when the first optical power is D1 and the second optical power is D2, the following conditional expression (1) is satisfied.

0.45 <D2 / D1 <0.55 (1)
Therefore, in the electronic eyeglasses 10, the first optical power is added to each variable power region when viewing the close-up region, and for example, when viewing the intermediate region separated by the distance from the monitor when operating the personal computer, each variable power region is used. A second optical power may be added to the. By changing the optical power applied to each variable power region in this way, it is possible to realize the electronic eyeglasses 10 (electrically active lenses 11, 12) capable of focusing on both the close region and the intermediate region. it can.

FIG. 4 is a front view of the electrically activated lens 11. The outer shape of the electroactive lens 11 is processed to correspond to the shape of the frame 13. Further, the shapes of the front surface and the rear surface of the electroactive lens 11 are processed according to the power to be corrected by the user. The variable power region 101 is formed on the nasal side of the user from the center of the electrically activated lens 11. The variable power region 101 has a plurality of annular electrodes arranged concentrically. The plurality of annulus electrodes have annulus electrodes 1, 2, 3 and 4. The annular electrodes 1, 2, 3 and 4 are connected to the lead wires 51, 52, 53 and 54, respectively. Each lead wire extends to the outer circumference of the electroactive lens 11 and is electrically connected to the cable 16.

Hereinafter, a method of controlling each variable power region when each variable power region is switched between the first state and the second state will be described with reference to FIGS. 5 to 8. FIG. 5 is a cross-sectional view and an optical phase difference distribution of the variable power region 101 (102) in the first state. FIG. 6 is a cross-sectional view of the variable power region 101 (102) and an optical phase difference distribution in the second state. FIG. 7 is an explanatory diagram of a control method of the variable power region 101 (102) in the first state. FIG. 8 is an explanatory diagram of a control method of the variable power region 101 (102) in the second state.

FIG. 5A is a configuration diagram (cross-sectional view) of the variable power region 101 (102) in the first state. The variable power region 101 (102) is sandwiched between a first substrate having a flat surface or a surface having a constant curvature and a second substrate having a flat surface or a surface having a constant curvature.

The plurality of ring-shaped electrodes have optically transparent ring-shaped electrodes 1, 2, 3, and 4. The electrode layer 5 is optically transparent and is provided so as to face the plurality of annular electrodes. Each annulus electrode and electrode layer 5 are composed of, for example, a permeable conductive oxide (ITO, titanium oxide, zinc oxide, or a mixture thereof) or a conductive organic material (PEDOT: PSS or carbon nanotube). ..

The liquid crystal layer 6 is provided between the plurality of annular electrodes and the electrode layer 5. The orientation distribution of the liquid crystal layer 6 can be adjusted by controlling the voltage applied to the plurality of annular electrodes and the electrode layer 5 by the controller unit 31 (32). By adjusting the orientation distribution of the liquid crystal layer 6, it is possible to impart a desired optical retardation distribution to the incident light.

The alignment film (not shown) is provided so as to be in contact with the liquid crystal layer 6. The alignment film is a thin film and is made of, for example, a polyimide material. The thickness of the alignment film is preferably 0.1 μm or less. The alignment film is subjected to a rubbing treatment or a photoalignment treatment in which ultraviolet rays are linearly polarized and irradiated. Thereby, the initial orientation of the liquid crystal molecules inside the liquid crystal layer 6 can be controlled.

The resistance layer 7 is optically transparent and is provided between the plurality of annular electrodes and the liquid crystal layer 6. By providing the resistance layer 7, it is possible to smoothly change the voltage between the annular electrodes to which voltages of different magnitudes are applied. The resistance layer 7 is composed of, for example, a permeable conductive oxide (zinc oxide) or a conductive organic material (PEDOT: PSS or carbon nanotube). The thickness of the resistance layer 7 is preferably 0.01 μm or more and 1 μm or less.

The insulating layer 8 is optically transparent and is provided between the plurality of annular electrodes and the resistance layer 7. The insulating layer 8 electrically insulates between the annular electrodes. The insulating layer 8 is made of, for example, silicon dioxide (SiO ₂ ). The thickness of the insulating layer 8 is preferably 0.1 μm or more and 5 μm or less.

FIG. 5B is a diagram showing an optical phase difference distribution that occurs in the liquid crystal layer 6 when the variable power region 101 (102) is in the first state. The thickness of the liquid crystal layer 6 can be reduced by adopting an optical phase difference distribution having a Fresnel lens shape or a diffraction lens shape. In order to acquire the optical phase difference distribution of the Fresnel lens shape or the diffractive lens shape, the plurality of annular electrodes are arranged concentrically. The size of each annular electrode is determined by the shape of the optical retardation distribution. The distance (radius) rn from the center of the plurality of annular electrodes to the position where the optical phase difference is switched is expressed by the following equation (2).

rn = n ^1/2 x r1 (2)
However, r1 is the distance from the center to the position where the optical phase difference closest to the center is switched, and n is an integer.

The plurality of ring-shaped electrodes have a plurality of electrode pairs in which two ring-shaped electrodes are paired. Each of the plurality of electrode pairs is arranged so that the position where the optical phase difference is switched is located between the annular electrodes.

The plurality of electrode pairs have an electrode pair consisting of annulus electrodes 1 and 2 (first electrode pair) and an electrode pair consisting of annulus electrodes 3 and 4 (second electrode pair). The second electrode pair is arranged at the position closest to the center of the plurality of annular electrodes among the plurality of electrode pairs. Further, the first electrode pair is arranged at a position adjacent to the second electrode pair, that is, at a position closest to the center of the plurality of annular electrodes among the plurality of electrode pairs. In the present embodiment, the first and second electrode pairs are alternately arranged from the centers of the plurality of annular electrodes in this order.

The controller unit 31 (32) controls the voltage applied to each annular electrode in response to the signal from the sensor unit 21 (22). In the first state, the first voltage V1 is applied to the annular electrodes 1 and 3, and the second voltage V2 higher than the first voltage V1 is applied to the annular electrodes 2 and 4. At this time, the switch unit SW1 is controlled so that the first voltage V1 is applied to the annular electrode 3, and the switch unit SW2 is controlled so that the second voltage V2 is applied to the annular electrode 4. .. As a result, the optical phase difference distribution shown in FIG. 5B can be obtained.

FIG. 6A is a configuration diagram of the variable power region 101 (102) 101 in the second state. FIG. 6B is a diagram showing an optical phase difference distribution that occurs in the liquid crystal layer 6 when the variable power region 101 (102) is in the second state.

In the second state, the first voltage V1 is applied to the annular electrode 1 and the second voltage V2 is applied to the annular electrode 2 as in the first state. Further, a third voltage V3 higher than the first voltage is applied to the annular electrode 3, and a fourth voltage V4 lower than the second voltage V2 is applied to the annular electrode 4. At this time, the switch unit SW1 is controlled so that the third voltage V3 is applied to the annular electrode 3, and the switch unit SW2 is controlled so that the fourth voltage V4 is applied to the annular electrode 4. .. As a result, the optical phase difference distribution shown in FIG. 6B can be obtained.

By switching the optical power applied to the variable power region 101 (102) in this way, it is possible to realize the electronic eyeglasses 10 capable of focusing on both the close region and the intermediate region.

In the present embodiment, the absolute value of the difference between the third and fourth voltages V3 and V4 is set to be smaller than the absolute value of the difference between the first and second voltages V1 and V2. In this embodiment, the third and fourth voltages V3 and V4 are set to be substantially equal to each other.

Further, in the present embodiment, the third and fourth voltages V3 and V4 are set to be substantially equal to the average value (= V1 + V2 / 2) of the first and second voltages V1 and V2. That is, among the positions where the optical phase difference is switched, the electrodes arranged at the positions where the subscript n of the distance rn from the center of the plurality of annular electrodes represented by the equation (1) to the position where the optical phase difference is switched is an odd number. Such a voltage (= (V1 + V2) / 2) is applied to the pair. As a result, in the second state, it is possible to acquire an optical phase difference distribution in which the switching pitch of the optical phase difference is twice that of the optical phase difference distribution in the first state.

Further, in the present embodiment, in the first state, the first voltage V1 is applied to the annular electrodes 1 and 3, and the second voltage V2 is applied to the annular electrodes 2 and 4. A second voltage V2 may be applied to the electrodes 1 and 3, and a first voltage V1 may be applied to the annular electrodes 2 and 4. At this time, in the second state, the fourth voltage V4 may be applied to the annular electrode 3 and the third voltage V3 may be applied to the annular electrode 4.

Hereinafter, a method for manufacturing a plurality of annular electrodes will be described with reference to FIG. 9. FIG. 9 is an explanatory diagram of a method for manufacturing a plurality of annular electrodes. First, as shown in FIG. 9A, a uniform electrode layer is formed on the glass substrate by using thin film deposition or sputtering. Next, as shown in FIG. 9B, a uniform electrode layer is patterned into a concentric ring band shape by etching to prepare a plurality of ring band electrodes. Next, as shown in FIG. 9C, a uniform insulating layer 8 is formed on the plurality of annular electrodes by using thin film deposition or sputtering. Next, as shown in FIG. 9D, a rectangular opening is formed by etching on the annular electrode to be electrically connected. Next, as shown in FIG. 9E, a lead electrode layer is formed by vapor deposition or sputtering, and patterning is performed by etching to form a lead wire 51. Finally, as shown in FIG. 9F, in procedure F, a uniform resistance layer 7 is formed by using thin film deposition or sputtering.

In the present embodiment, when the surface resistivity of the resistance layer 7 is R1 and the surface resistivity of the insulating layer 8 is R2, it is preferable that the following conditional expression (3) is satisfied.

1 × ^10-5 <R1 / R2 <1 × ^10-2 (3)
By satisfying the conditional expression (3), the area of the variable power region 101 (102) can be sufficiently widened. If the upper limit of the conditional expression (3) is exceeded, the potential distribution with respect to the liquid crystal layer 6 does not have a Fresnel lens shape or a diffractive lens shape, and a smooth refractive index distribution cannot be given to the liquid crystal layer 6, which is not preferable. If it is less than the lower limit of the relational expression (3), the absolute value of the potential with respect to the liquid crystal layer becomes too small, and a sufficient refractive index distribution cannot be given to the liquid crystal layer 6, which is not preferable.

Further, it is preferable that the numerical range of the conditional expression (3) is the range of the following conditional expression (3a).

0.5 × 10 ^-4 <R1 / R2 <0.8 × 10 ^-2 (3a)
Further, it is more preferable that the numerical range of the conditional expression (3) is the range of the following conditional expression (3b).

1.0 × 10 ^-4 <R1 / R2 <0.6 × 10 ^-2 (3b)
Further, the surface resistivity R1 of the resistance layer 7 preferably satisfies the following conditional expression (4).

1 × 10 ⁵ ≦ R1 ≦ 1 × 10 ¹⁰ (4)
Further, the surface low efficiency R2 of the insulating layer 8 preferably satisfies the following conditional expression (5).

1 × 10 ¹¹ ≦ R2 ≦ 1 × 10 ¹⁵ (5)
Further, the electrically active lenses 11 and 12 or an optical element having a similar configuration can be used not only for the electronic eyeglasses 10 but also for various optical devices such as binoculars and a head-mounted display. According to the configuration of the present embodiment, it is possible to easily manufacture an optical element having a plurality of states having different optical powers from each other and an optical device using the same.

Hereinafter, in each embodiment, the configuration of the electronic eyeglasses 10 will be described using specific numerical values.

FIG. 10 is a diagram showing the orientation distribution of the liquid crystal molecules in the first state of this embodiment, which is acquired by simulation. FIG. 11 is a diagram showing an optical retardation distribution generated in the liquid crystal layer 6 in the first state of this embodiment.

The simulation conditions will be described below. The material of the plurality of annular electrodes and the electrode layer 5 is ITO. The material of the liquid crystal layer 6 is a nematic liquid crystal E7. The birefringence Δn of the nematic liquid crystal E7 is 0.22 with respect to light having a wavelength of 550 nm. The thickness of the liquid crystal layer 6 is 30 μm. The pretilt angle is 3 ° on the upper surface and the lower surface of the liquid crystal layer 6. The material of the resistance layer 7 is a compound containing zinc oxide (ZnO) as a main component. The thickness of the resistance layer 7 is 0.5 μm. The surface resistivity of the resistance layer 7 is 2 × 10 ⁸ Ω, and the electrical resistivity is 1 × 10 ⁴ Ω · cm. The material of the insulating layer 8 is silicon dioxide (SiO ₂ ). The thickness of the insulating layer 8 is 1 μm. The surface resistivity of the insulating layer 8 is 1 × 10 ¹¹ Ω, and the electrical resistivity is 1 × 10 ⁷ Ω · cm. The ratio of the surface resistivity of the resistance layer 7 to the surface resistivity of the insulating layer 8 is 2.0 × 10 ^-3 , which satisfies the conditional expression (3). The first and second voltages V1 and V2 are a voltage of AC1V having a frequency of 1 kHz and a voltage of AC3V having a frequency of 1 kHz, respectively. The electrode layer 5 is grounded, and the voltage applied to the electrode layer 5 is 0 V.

In FIG. 10, the left end is the center position of the variable power region 101 (102), and the distance from the right end to the left end is 10 mm. That is, the diameter of the variable power region 101 (102) is 20 mm. At the position where the first voltage V1 is applied, the liquid crystal molecules are collapsed and the effective refractive index becomes high. At the position where the second voltage V2 is applied, the liquid crystal molecules rise according to the direction of the electric field, and the effective refractive index becomes low. Further, in the region between the positions where the first and second voltages V1 and V2 are applied, the voltage changes smoothly due to the action of the resistance layer 7, so that the orientation of the liquid crystal molecules also changes smoothly. .. As a result, a smooth refractive index distribution can be realized, and as shown in FIG. 11, a smooth optical retardation distribution of the Fresnel lens shape can be obtained.

FIG. 12 is a diagram showing the orientation distribution of the liquid crystal molecules in the second state of this embodiment, which is acquired by simulation. FIG. 13 is a diagram showing an optical retardation distribution generated in the liquid crystal layer 6 in the second state of this embodiment.

The simulation conditions used when acquiring the orientation distribution of FIG. 12 are basically the same as the simulation conditions used when acquiring the orientation distribution of FIG. 10, but they are applied to the annular electrodes 3 and 4. The third and fourth voltages V3 and V4 are different.

The third and fourth voltages V3 and V4 are a voltage of AC2.1V having a wave number of 1 kHz and a voltage of AC1.9V having a frequency of 1 kHz, respectively. The third and fourth voltages V3 and V4 are substantially equal to the average value 2V (= (V1 + V2) / 2) of the voltages V1 and V2.

In FIG. 12, at the positions where the third and fourth voltages V3 and V4 are applied, the orientation of the liquid crystal molecules changes smoothly without being discontinuous. As shown in FIG. 13, it is possible to obtain a smooth optical retardation distribution having a Fresnel lens shape whose pitch is twice that of the optical retardation distribution in the first state. In this way, the average value of the first and second voltages V1 and V2 is applied to the electrode pairs arranged at the positions where the subscript n of the distance rn from the center of the plurality of annular electrodes to the position where the optical phase difference is switched is odd. Is applied. As a result, in the second state, it is possible to obtain a gentle optical retardation distribution in which the switching pitch of the optical retardation is twice that of the optical retardation distribution in the first state.

FIG. 14 is a diagram showing the orientation distribution of the liquid crystal molecules in the first state of this embodiment, which is acquired by simulation. FIG. 15 is a diagram showing an optical retardation distribution generated in the liquid crystal layer 6 in the first state of this embodiment.

The simulation conditions will be described below. The material of the plurality of annular electrodes and the electrode layer 5 is ITO. The material of the liquid crystal layer 6 is a nematic liquid crystal PCH-5. The birefringence Δn of the nematic liquid crystal PCH-5 is 0.12 with respect to light having a wavelength of 550 nm. The thickness of the liquid crystal layer 6 is 60 μm. The pretilt angle is 3 ° on the upper surface and the lower surface of the liquid crystal layer 6. The material of the resistance layer 7 is a compound containing zinc oxide (ZnO) as a main component. The thickness of the resistance layer 7 is 0.5 μm. The surface resistivity of the resistance layer 7 is 5 × 10 ⁸ Ω, and the electrical resistivity is 2.5 × 10 ⁴ Ω · cm. The material of the insulating layer 8 is silicon dioxide (SiO ₂ ). The thickness of the insulating layer 8 is 1 μm. The surface resistivity of the insulating layer 8 is 1 × 10 ¹¹ Ω, and the electrical resistivity is 1 × 10 ⁷ Ω · cm. The ratio of the surface resistivity of the resistance layer 7 to the surface resistivity of the insulating layer 8 is 5.0 × 10 ^-3 , which satisfies the conditional expression (3). The first and second voltages V1 and V2 are a voltage of AC1V having a frequency of 1 kHz and a voltage of AC3V having a frequency of 1 kHz, respectively. The electrode layer 5 is grounded, and the voltage applied to the electrode layer 5 is 0 V.

In FIG. 14, the left end is the center position of the variable power region 101 (102), and the distance from the right end to the left end is 10 mm. That is, the diameter of the variable power region 101 (102) is 20 mm. In this embodiment, the electrodes 9 are arranged at the centers of the plurality of annular electrodes in order to adjust the orientation of the liquid crystal molecules in the central portion of the variable power region 101 (102). At the position where the first voltage V1 is applied, the liquid crystal molecules are collapsed and the effective refractive index becomes high. At the position where the second voltage V2 is applied, the liquid crystal molecules rise according to the direction of the electric field, and the effective refractive index becomes low. Further, in the region between the positions where the first and second voltages V1 and V2 are applied, the voltage changes smoothly due to the action of the resistance layer 7, so that the orientation of the liquid crystal molecules also changes smoothly. .. As a result, a smooth refractive index distribution can be realized, and as shown in FIG. 15, a smooth optical retardation distribution of the Fresnel lens shape can be obtained.

FIG. 16 is a diagram showing the orientation distribution of the liquid crystal molecules in the second state of this embodiment, which is acquired by simulation. FIG. 17 is a diagram showing an optical retardation distribution generated in the liquid crystal layer 6 in the second state of this embodiment.

The simulation conditions used when acquiring the orientation distribution of FIG. 16 are basically the same as the simulation conditions used when acquiring the orientation distribution of FIG. 14, but are applied to the annular electrodes 3 and 4. The third and fourth voltages V3 and V4 are different.

The third and fourth voltages V3 and V4 are a voltage of AC2.1V having a wave number of 1 kHz and a voltage of AC1.9V having a frequency of 1 kHz, respectively. The third and fourth voltages V3 and V4 are substantially equal to the average value 2V (= (V1 + V2) / 2) of the voltages V1 and V2.

In FIG. 16, at the positions where the third and fourth voltages V3 and V4 are applied, the orientation of the liquid crystal molecules changes smoothly without being discontinuous. As shown in FIG. 17, it is possible to obtain a smooth optical retardation distribution having a Fresnel lens shape whose pitch is twice that of the optical retardation distribution in the first state. In this way, the average value of the first and second voltages V1 and V2 is applied to the electrode pairs arranged at the positions where the subscript n of the distance rn from the center of the plurality of annular electrodes to the position where the optical phase difference is switched is odd. Is applied. As a result, in the second state, it is possible to obtain a gentle optical retardation distribution in which the switching pitch of the optical retardation is twice that of the optical retardation distribution in the first state.

FIG. 18 is a diagram showing the potential distribution of the liquid crystal layer 6 in the first state of this embodiment, which is acquired by simulation. FIG. 19 is a diagram showing an optical retardation distribution acquired from the potential distribution of FIG. 18, which is acquired by simulation.

The simulation conditions will be described below. The material of the plurality of annular electrodes and the electrode layer 5 is ITO. The material of the liquid crystal layer 6 is nematic liquid crystal 5CB. The birefringence Δn of the nematic liquid crystal 5CB is 0.18 with respect to light having a wavelength of 550 nm. The thickness of the liquid crystal layer 6 is 50 μm. The pretilt angle is 3 ° on the upper surface and the lower surface of the liquid crystal layer 6. The material of the resistance layer 7 is a compound containing zinc oxide (ZnO) as a main component. The thickness of the resistance layer 7 is 0.5 μm. The surface resistivity of the resistance layer 7 is 2.5 × 10 ⁸ Ω, and the electrical resistivity is 1.25 × 10 ⁴ Ω · cm. The material of the insulating layer 8 is silicon dioxide (SiO ₂ ). The thickness of the insulating layer 8 is 1 μm. The surface resistivity of the insulating layer 8 is 1 × 10 ¹² Ω, and the electrical resistivity is 1 × 10 ⁸ Ω · cm. The ratio of the surface resistivity of the resistance layer 7 to the surface resistivity of the insulating layer 8 is 2.5 × 10 ^-4 , which satisfies the conditional expression (3). The first and second voltages V1 and V2 are a voltage of AC0.5V having a frequency of 1 kHz and a voltage of AC2.2V having a frequency of 1 kHz, respectively. The electrode layer 5 is grounded, and the voltage applied to the electrode layer 5 is 0 V.

As shown in FIG. 18, it is possible to give the liquid crystal layer 6 a smooth Fresnel lens-shaped potential distribution. Further, as shown in FIG. 19, it is possible to obtain an optical retardation distribution having a smooth Fresnel lens shape.

FIG. 20 is a diagram showing the potential distribution of the liquid crystal layer 6 of the comparative example, which is acquired by simulation. The simulation conditions used when acquiring the potential distribution of the liquid crystal layer 6 of FIG. 20 are basically the same as the simulation conditions used when acquiring the potential distribution of the liquid crystal layer 6 of FIG. 18, but the resistance layer. The surface resistivity of 7 is changed to ^{2.5 × 10 6 Ω.} The ratio of the surface resistivity of the resistance layer 7 to the surface resistivity of the insulating layer 8 is 2.5 × ^10-6 , which does not satisfy the conditional expression (3). As shown in FIG. 20, the potential distribution with respect to the liquid crystal layer 6 does not have a Fresnel lens shape or a diffractive lens shape, and a smooth refractive index distribution cannot be given to the liquid crystal layer 6.

FIG. 21 is a diagram showing the potential distribution of the liquid crystal layer 6 of the comparative example, which is acquired by simulation. The simulation conditions used when acquiring the potential distribution of the liquid crystal layer 6 of FIG. 21 are basically the same as the simulation conditions used when acquiring the potential distribution of the liquid crystal layer 6 of FIG. 18, but the resistance layer. The surface resistivity of 7 is changed to ^{2.5 × 10 10 Ω.} The ratio of the surface resistivity of the resistance layer 7 to the surface resistivity of the insulating layer 8 is 2.5 × ^10-2 , which does not satisfy the conditional expression (3). As shown in FIG. 21, the absolute value of the potential with respect to the liquid crystal layer 6 becomes too small, and a sufficient refractive index distribution cannot be given to the liquid crystal layer 6.

As described above, in order to give the liquid crystal layer 6 a desired refractive index distribution, it is preferable that the surface resistivity of the resistance layer 7 and the surface resistivity of the insulating layer 8 satisfy the conditional equation (3).

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and modifications can be made within the scope of the gist thereof.

1 ring band electrode (first ring band electrode)
2 ring band electrode (2nd ring band electrode)
3 ring band electrode (third ring band electrode)
4 ring band electrode (4th ring band electrode)
5 Electrode layer 6 Liquid crystal layer 10 Electronic glasses (optical equipment)
11,12 Electrically activated lens (optical element)
31, 32 Controller unit (control unit)

Claims (12)

An optical element including a plurality of annular electrodes arranged concentrically, an electrode layer facing the plurality of annular electrodes, and a liquid crystal layer provided between the plurality of annular electrodes and the electrode layer. ,
It has a control unit that changes the optical element into an electrically activated state and an electrically inactivated state.
The plurality of ring-shaped electrodes include a first ring-shaped electrode, a second ring-shaped electrode, a third ring-shaped electrode, and a fourth ring-shaped electrode.
The electrically activated state includes a first state in which the optical element has a first optical power and a second state in which the optical element has a second optical power smaller than the first optical power.
A first voltage is applied to the first annulus electrode in the first and second states.
A second voltage higher than the first voltage is applied to the second annulus electrode in the first and second states.
In the first state, the first voltage is applied to the third ring electrode, and in the second state, a third voltage higher than the first voltage is applied.
The fourth annulus electrode is characterized in that the second voltage is applied in the first state and a fourth voltage lower than the second voltage is applied in the second state. Optical equipment. The plurality of annulus electrodes include a first electrode pair composed of the first and second electrodes and a second electrode pair composed of the third and fourth annulus electrodes.
The second electrode pair is arranged at a position closest to the center of the plurality of annular electrodes.
The optical device according to claim 1, wherein the first electrode pair is arranged at a position adjacent to the second electrode pair. The plurality of annulus electrodes include a plurality of the first electrode pairs and a plurality of the second electrode pairs.
The optical device according to claim 2, wherein the first and second electrode pairs are arranged alternately. The optical device according to any one of claims 1 to 3, wherein the absolute value of the difference between the third and fourth voltages is smaller than the absolute value of the difference between the first and second voltages. .. The optical device according to any one of claims 1 to 4, wherein the third and fourth voltages are equal to each other. The optical device according to any one of claims 1 to 5, wherein the third and fourth voltages are equal to the average value of the first and second voltages. When the first optical power is D1 and the second optical power is D2,
0.45 <D2 / D1 <0.55
The optical element according to any one of claims 1 to 6, wherein the optical element satisfies the conditional expression. A resistance layer provided between the plurality of annular electrodes and the liquid crystal layer,
The optical device according to any one of claims 1 to 7, further comprising an insulating layer provided between the plurality of annular electrodes and the resistance layer. When the surface resistivity of the resistance layer is R1 and the surface resistivity of the insulating layer is R2,
1 × 10 ^-5 <R1 / R2 <1 × 10 ^-2
The optical device according to claim 8, wherein the optical device satisfies the conditional expression. When the surface resistivity of the resistance layer is R1,
1 × 10 ⁵ ≦ R1 ≦ 1 × 10 ¹⁰
The optical device according to claim 8 or 9, wherein the optical device satisfies the conditional expression. When the surface resistivity of the insulating layer is R2,
1 × 10 ¹¹ ≦ R2 ≦ 1 × 10 ¹⁵
The optical device according to any one of claims 8 to 10, wherein the optical device satisfies the conditional expression. An optical element that changes between an electrically activated state and an electrically inactivated state.
Multiple annulus electrodes arranged concentrically,
An electrode layer facing the plurality of annular electrodes and
A liquid crystal layer provided between the plurality of annular electrodes and the electrode layer,
A resistance layer provided between the plurality of annular electrodes and the liquid crystal layer,
It has an insulating layer provided between the plurality of annular electrodes and the resistance layer, and has an insulating layer.
The electrically activated state includes a first state in which the optical element has a first optical power and a second state in which the optical element has a second optical power smaller than the first optical power.
When the surface resistivity of the resistance layer is R1 and the surface resistivity of the insulating layer is R2,
1 × 10 ^-5 <R1 / R2 <1 × 10 ^-2
An optical element characterized by satisfying the conditional expression.

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