JP2022035591A - Liquid crystal optical device - Google Patents

Abstract

To provide a liquid crystal optical device that can drive stably for a long time at low voltage without the frequency dependence and has the smooth and continuous optical phase difference characteristic and the excellent optical characteristic.SOLUTION: A liquid crystal optical device includes a liquid crystal layer 31 where liquid crystal molecules contained between a first substrate 11 with a transparent electrode and a second substrate 12 with a transparent electrode are oriented. At least the transparent electrode on a surface of the second substrate 12 includes a center electrode 220 and a group of a plurality of concentric electrodes 221 to 229 that are held at the stepwise voltages. A transparent insulating layer 41 is disposed between the center electrode 220 and the group of concentric electrodes 221 to 229, and the liquid crystal layer 31. The total of the thickness of the transparent insulating layer 41 and the thickness of the liquid crystal layer 31 is larger than the total of the average of the widths of the concentric electrodes 221 to 229 and the average of the distances between the electrode and the adjacent electrode.SELECTED DRAWING: Figure 1

Description

The present invention relates to a thin liquid crystal optical device having a structure that does not use a high resistance film, has a smooth refractive index distribution characteristic, and can variably adjust the optical characteristic by a low voltage.

Liquid crystals show dielectric anisotropy and optical anisotropy, and have the characteristic that the effective refraction coefficient can be continuously variably adjusted from the value for general abnormal light to the value for normal light by applying a relatively low voltage, for example. , Optics such as a voltage-variable liquid crystal lens that operates by providing a liquid crystal layer between the first transparent electrode and the second transparent electrode and controlling the effective refractive index distribution of the liquid crystal layer by the voltage between the electrodes. The device has been reported.

As a variable focus lens using a liquid crystal, a flat plate-shaped first electrode, a pattern electrode having a circular opening, and a second transparent electrode composed of a circular center electrode provided in the circular opening. By inserting a liquid crystal layer between the lenses, inserting a transparent insulating layer between the second transparent electrode and the liquid crystal layer, and arranging the second transparent electrode at a certain distance from the liquid crystal layer. Even if the diameter of the opening of the electrode is increased to some extent, the non-uniform electric field of axial symmetry spreads to the vicinity of the center of the opening, that is, the vicinity of the center of the circular center electrode, and the effective refraction coefficient of the liquid crystal with respect to the incident light. Patent Document 1 proposes a method of exhibiting a good lens effect by varying the amount of light, and reports a liquid crystal lens having a diameter of about several mm.

However, in the liquid crystal lens reported in Patent Document 1, there is a special relationship between the diameter of the lens, that is, the diameter of the circular opening and the thickness of the transparent insulating layer in order to obtain good optical characteristics, and the lens is transparent. Since the insulating layer cannot be thinned, the drive voltage becomes as high as 100 V or more when a lens having a diameter of 2 mm is used, and when the diameter is further increased, a high voltage of several hundred V or more is required.

To solve the difficulty of the liquid crystal lens disclosed in Patent Document 1, the second transparent electrode composed of a pattern electrode having a circular opening and a circular center electrode provided in the opening. By providing a double layer consisting of a transparent insulating layer and a transparent high resistance layer between the liquid crystal layers, an axially symmetric non-uniform electric field is circular due to the potential distribution on the high resistance film surface even if the thickness of the transparent insulating layer is reduced. It is reported in Patent Document 2 as a liquid crystal lens that can be driven at a low voltage because it can be formed up to the center of the center electrode of the shape and the transparent insulating layer can be thinned.

On the other hand, a circular center electrode and a plurality of ring bands (which may be referred to as circle bands) arranged concentrically at intervals around the center electrode (hereinafter referred to as ring band shape). The second transparent electrode (concentric pattern electrode group) is formed by the electrode pattern, a liquid crystal layer is inserted between the second transparent electrode and the flat plate-shaped first electrode, and a voltage is applied to the plurality of annular electrodes. By forming a voltage distribution in the radial direction from the center electrode, a refractive index distribution can be generated in the radial direction also in the liquid crystal layer, and a liquid crystal optical device operating at a low voltage is disclosed in Patent Documents 3 and 4. Has been done.

However, in a liquid crystal optical device using these a plurality of ring-shaped patterned electrodes, the voltage applied to the liquid crystal layer does not have a continuous and smooth potential distribution such as a stepped shape or a stepped shape including an inclination, so that the refractive index distribution is not obtained. Similarly, since the characteristics are discontinuous like a stepped shape or a stepped shape including an inclination, it is difficult to construct a liquid crystal optical device having good optical characteristics, and the problem is that the ideal lens characteristics are not obtained. There was a point. In order to solve such a problem, by arranging a double layer composed of an insulating layer and an impedance layer or a high resistance layer between the second transparent electrode and the liquid crystal layer, the refractive index distribution of the liquid crystal layer can be made continuous. Liquid crystal optical devices that are smooth, have good optical characteristics, and can operate at a low voltage are disclosed in Patent Documents 5 and 6.

Japanese Unexamined Patent Publication No. 2004-4616 Japanese Unexamined Patent Publication No. 2008-203360 Japanese Unexamined Patent Publication No. 05-53089 Japanese Unexamined Patent Publication No. 2004-334028 Japanese Unexamined Patent Publication No. 2012-137682 Japanese Unexamined Patent Publication No. 2018-36483

The liquid crystal optical device (liquid crystal lens) disclosed in Patent Document 2 and Patent Document 5 and Patent Document 6 uses a transparent impedance layer or a transparent high resistance layer, so that good optical characteristics can be obtained. The disadvantage is that the frequency dependence of the drive voltage is large, and since a high resistance value of about 100 MΩ is required as an impedance layer or a high resistance layer depending on the device dimensions, reproducibility and long-term stable resistance are required. There was a problem that it was difficult to keep the value.

Therefore, an object of the present invention is a structure that does not use a high resistance layer in order to solve the above problems, operates at a low voltage, has a continuous and smooth refractive index distribution and good optical characteristics, and has a drive voltage. It is an object of the present invention to provide a liquid crystal optical device that does not depend on the frequency of the above.

In order to solve the above problems, the present application comprises a liquid crystal layer in which liquid crystal molecules accommodated between a first substrate having a transparent electrode and a second substrate having a transparent electrode are oriented, and at least the above-mentioned first. The transparent electrodes on the surface of the substrate of 2 are formed from a center electrode held at a voltage in which each is stepped and a plurality of concentric electrodes.
A transparent insulating layer is arranged between the center electrode, a plurality of concentric electrodes, and the liquid crystal layer, and the center electrode, the concentric electrodes, and the transparent electrode of the first substrate face each other. A liquid crystal optical device that operates by adjusting the distribution of the effective refractive electrode of the liquid crystal layer in each region.
It is preferable that the sum of the thickness of the transparent insulating layer and the thickness of the liquid crystal layer is larger than the sum of the average value of the widths of the concentric electrodes and the average value of the intervals between the electrodes and other electrodes adjacent to the electrodes.

In the liquid crystal optical device, an independent voltage is applied between each of the center electrode and the outermost electrode and the electrode of the first substrate, and the outermost electrode is transparent from the center electrode via the adjacent electrode. It is connected by a resistance film, and as the resistance value of the transparent resistance film moves from the center to the outside, the resistance values between the electrodes adjacent to the inside are equal to each other or may have a larger resistance value. Further, in the liquid crystal optical device, it is preferable that the resistance value of the transparent resistance film has a value depending on a function of approximately 4th order or higher with the distance from the center as a variable or a value close to the step thereof.

Further, in the liquid crystal optical device, the central electrode and the outermost concentric electrode or any of the electrodes are arranged in the transparent insulating layer or on the liquid crystal layer side of the transparent insulating layer, and the transparent electrode is arranged. It is possible to operate by applying a voltage between each of the electrodes arranged in the insulating layer or on the liquid crystal layer side of the transparent insulating layer and the concentric electrodes adjacent to the electrodes and the electrode of the first substrate. ..

Further, a plurality of concentric electrode groups are set as a set, and at least one set of concentric electrode groups is arranged outside the outermost concentric electrodes, and the distribution characteristics of the optical phase difference in each adjacent set are arranged. However, it is also possible to operate by applying a voltage such that the optical phase difference distribution characteristic of the liquid crystal optical device is extrapolated. Further, by using a band-shaped electrode group extended in one direction instead of the concentric electrode group, it can be operated as a liquid crystal optical device having a function of deflecting the direction of incident light.

In the present invention, a transparent insulating layer is arranged between a circular center electrode layer, a plurality of concentric transparent electrode groups, and the liquid crystal layer, and the sum of the thickness of the transparent insulating layer and the thickness of the liquid crystal layer is concentric. By making it larger than the sum of the average value of the width of the transparent electrode and the average value of the distance between the electrode and other electrodes adjacent to the electrode, the transparent impedance layer has difficulty in reproducibility and has a large secular change. Discontinuous or stepped refractive index distribution characteristics based on the discontinuous potential distribution by the plurality of concentric transparent electrode groups are made smooth and continuous without using a transparent high resistance layer. Provided is a liquid crystal optical device that can change the optical characteristics significantly and efficiently by electrical control without having a mechanical moving part such as back-and-forth movement, having a simple structure without frequency dependence. ..

1 (A) is a configuration explanatory view showing an embodiment of a liquid crystal optical device according to the present invention, and FIG. 1 (B) is a second substrate and electrode groups 220 to 229 of FIG. 1 (A). It is a plan view. FIG. 2 shows an example of a change in the voltage applied to the liquid crystal optical device depending on the position in the radial direction. The approximate curve of the 6th-order function is shown in the figure, and the approximate expression of the 6th-order function is also shown. FIG. 3 shows a cross section of an optical phase difference distribution generated in a liquid crystal layer in a liquid crystal optical device having no transparent insulating layer when a voltage having a voltage value shown in FIG. 2 is applied to each of the electrode groups 220 to 229. It is a figure. In FIG. 4, a voltage is applied to each of the electrode groups 220 to 229 of the liquid crystal optical device provided with the transparent insulating layer having a thickness of 20 μm, in which the absolute value of the voltage distribution shown in FIG. 2 is slightly increased by the amount of the transparent insulating layer. It is sectional drawing of the optical phase difference distribution characteristic which occurs in the liquid crystal layer in the case of this. FIG. 5 is a cross-sectional view of the optical phase difference distribution characteristic generated in the liquid crystal layer when the thickness of the transparent insulating layer is increased to 50 μm. FIG. 6 is a cross-sectional view of the optical phase difference distribution characteristic generated in the liquid crystal layer when the thickness of the transparent insulating layer is further increased to 120 μm. FIG. 7 is a cross-sectional view of (A) the optical phase difference distribution characteristic generated in the liquid crystal layer in the liquid crystal optical device having the Frenel structure according to the third embodiment, and (B) the optical phase difference distribution characteristic extrapolated from the optical phase difference distribution characteristic. It is a cross-sectional view of. In FIG. 8, in the electrode structure shown in FIG. 1, the central electrode and the outermost electrode are arranged on the liquid crystal layer side of the transparent insulating layer, and the electrodes arranged on the liquid crystal layer side and the liquid crystal layer side are shown in FIG. It is a block diagram which shows one Embodiment of the liquid crystal optical device which operates by applying a voltage between the concentric electrode adjacent to the arranged electrode, and the electrode of a 1st substrate. 9A and 9B are a cross-sectional view of (A) an optical phase difference distribution characteristic generated in a liquid crystal layer in a liquid crystal optical device having a Frenel structure according to Example 5, and (B) an optical phase difference distribution characteristic extrapolated by the optical phase difference distribution characteristic. It is a cross-sectional view of.

The present invention has been devised for the purpose of solving various problems in the prior art. That is, in the technique of Patent Document 1, it is a problem to reduce the drive voltage, and in Patent Document 2, it is a problem to relax the frequency dependence of the drive voltage. Further, in Patent Documents 3 and 4, it is an object to make the stepped optical retardation distribution continuous and smooth characteristics.

The above problem was solved by arranging a transparent insulating layer and a double layer made of a transparent impedance layer or a high resistance layer which is not connected to any of the electrodes between the concentric transparent ring-shaped electrodes and the liquid crystal layer. In the techniques of Patent Documents 5 and 6, it is necessary to set the impedance or resistance value of the transparent impedance layer or the high resistance layer to a high value, so that the reproducibility at the time of manufacturing the device and the long term are required. Stability is an issue, and the frequency characteristics of the drive power supply are also issues.

Based on the above problems, the present invention operates at a low voltage without using a transparent impedance layer or a high resistance layer, which has difficulty in reproducibility and long-term stability, and has a continuous and smooth refractive index distribution. Also disclosed are liquid crystal optical devices having good optical properties and no frequency dependence of drive voltage.

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 describes the basic configuration thereof.

FIG. 1A shows a configuration in which a basic configuration of a liquid crystal optical device operating as a liquid crystal lens is viewed from a cross section as an embodiment of the present invention. The transparent electrode 21 is formed on the first substrate 11 and the second substrate 12 is superposed on the second substrate 12 via a spacer (not shown) for maintaining a predetermined thickness to form a liquid crystal cell. Between the first substrate 11 and the second substrate 12, a liquid crystal layer 31 in which liquid crystal molecules are oriented is provided so as to face the electrode 21.

An alignment film (not shown) having an effect of orienting liquid crystal molecules is arranged on the surface of the electrode 21 formed on the first substrate 11 in contact with the liquid crystal layer 31.

Further, electrode groups 220 to 229 are formed on the side of the second substrate 12 facing the liquid crystal layer, and a transparent insulating layer 41 and an alignment film (not shown) are laminated.

The alignment film formed on the surface of the transparent electrode 21 and the transparent insulating layer 41 in contact with the liquid crystal layer is subjected to a rubbing treatment called antiparallel in opposite directions to correspond to the long axis direction of the liquid crystal molecules. The director is oriented at an angle called a pretilt angle that is tilted about 1 degree from the substrate surface.

1 (B) is a plan view of the liquid crystal lens of FIG. 1 (A), and is an electrode 21 formed on the first substrate and an electrode formed on the second substrate 12. A first voltage V1 is applied from the first power source 81 to the circular electrode 220 at the center of the group. Further, a second voltage V2 can be applied from the second power supply 82 between the electrode 21 and the concentric outermost electrode 229 in the second electrode group. ..

Between each of the central circular electrode 220 and the concentric electrode groups 221 and 229, each electrode utilizes the voltage drop caused by the current flowing due to the difference between the potential due to the first voltage and the potential due to the second voltage. Are connected to each other with a predetermined resistance value (not shown) so that the potential becomes a predetermined potential. In order to apply a voltage to the central circular electrode 220, a method of using a leader wire insulated from other electrode groups or a method of making a fine hole in the second substrate 12 and passing the voltage through the leader wire outside the substrate. A method of applying the above can be applied.

It should be noted that an external lead wire is used between the central circular electrode 220, the concentric electrode groups 221 and 229, and the electrode 21 formed on the first substrate, respectively, which are insulated from other electrode groups. By applying a predetermined voltage from the electrode group 220, the liquid crystal optical device can be operated without providing a resistor between each of the electrode groups 220, 221 and to 229.

An electric field due to the distribution of the potential changing in the radial direction is applied to the liquid crystal layer 31, and the liquid crystal molecules are oriented depending on the respective electric field strengths.

In the initial state where no voltage is applied, the director corresponding to the long axis direction of the liquid crystal molecule is tilted about 1 degree, which is the pretilt angle, with respect to the alignment film surface on the electrode surface, and is oriented in the rubbing direction. Consider the case where it is. When V1 and V2 are 0, the effective refractive index of the liquid crystal layer is uniform in the in-plane direction of the substrate with respect to the incident light polarized in the direction of the director.

Next, when V1 and V2 are appropriately adjusted so that a voltage equal to or higher than the liquid crystal threshold is applied, the liquid crystal director rises at an angle perpendicular to the electrode substrate surface under the electrode where the voltage is high, and the voltage is low. Under the electrode, the angle at which the director rises from the electrode substrate surface becomes small. When the angle at which the director tilts with respect to the electrode substrate surface increases, the effective refractive index of the liquid crystal decreases, and conversely, as the tilt angle decreases, the effective refractive index of the liquid crystal increases, so it depends on the voltage level. Therefore, the angle formed by the director on the electrode substrate surface is different, and as a result, an effective refractive index is distributed in the liquid crystal layer.

Effective refraction is achieved by applying a voltage having a distribution such that the voltage of the circular electrode 220 at the center of the concentric pattern electrode group is the lowest and the voltage gradually increases toward the outermost electrode 229 in the radial direction. The refractive index distribution characteristic is such that the rate gradually decreases from the center toward the peripheral portion, and the liquid crystal layer has a convex lens function that converges with respect to the incident light polarized in the direction of the director of the liquid crystal.

On the contrary, when a voltage is applied so that the voltage of the outermost electrode 220 is the lowest and the voltage is gradually increased toward the central circular electrode 220 in the radial direction, the effective refraction coefficient is obtained. The refractive index distribution characteristic is gradually increased from the center to the peripheral portion, and the liquid crystal layer has a concave lens function that diverges with respect to the incident light polarized in the direction of the director of the liquid crystal.

By adjusting the structure of the concentric electrodes so that the effective refractive index distribution in the radial direction is a paraboloid with the quadratic function rotated around the axis, lens characteristics with small aberrations are obtained. be able to. Details of the operating principle of these liquid crystal lenses are described in Patent Document 1, Patent Document 2, Patent Document 3, and Patent Document 4.

Further, in the configuration shown in FIG. 1, when a transparent impedance layer or a high resistance layer is provided between the transparent insulating layer 41 and the liquid crystal layer 31, the liquid crystal molecule orientation effect, the electric field smoothing effect, and the optical phase difference Details of the operating principle such as the smoothing effect of the above are described in Patent Documents 5 and 6.

Next, a specific embodiment will be described. In FIG. 1, the first substrate 11 is a transparent glass plate having a thickness of 300 μm, and a transparent electrode 21 made of an indium tin oxide (ITO) is formed on the inner surface side in contact with the liquid crystal layer 31. The second substrate 12 is a glass substrate having a thickness of 300 μm, and on the side of the second substrate 12 in contact with the liquid crystal layer 31, the central circular ITO electrode 220 and the ITO electrode group 221 to 229, which form a plurality of transparent electrode groups, are formed. Are formed concentrically. A resistance adjusted so that the voltage of each electrode has a value as shown in FIG. 2 is connected between these electrode groups 220 to 229. Further, instead of providing a resistor, a voltage as shown in FIG. 2 may be applied to each electrode by using a lead wire.

The width of the outermost concentric electrodes can be wider than the width of the other inner electrodes, and the inside of the electrodes is required to be circular, but the overall shape is not necessarily concentric. The outer shape does not have to be circular, and may be any shape that matches the shape of the substrate 1 instead of being circular.

In the liquid crystal lens of the present invention, the transparent insulating layer 41 is arranged between the liquid crystal layer 31 and the second substrate 12 having the central circular electrode 220 and the concentric electrode group. RDP85475 (manufactured by DIC Corporation) is used as the liquid crystal material of the liquid crystal layer 31, and a polyimide film is applied to the surfaces of the electrodes 21 and the electrode groups 220 to 229 sandwiching the liquid crystal layer to a thickness of about 100 nm as an alignment film (not shown). Then, it is subjected to a rubbing treatment after being stabilized by heat treatment.

It is known that when the alignment process is performed by rubbing, the major axis direction of the liquid crystal molecules is generally tilted at a small angle called the pretilt angle of about 1 degree in one direction from the alignment film surface with respect to the rubbing direction. When the rubbing process is performed so that the rubbing directions with respect to the alignment film on the opposite substrate are opposite to each other, which is called anti-parallel, the liquid crystal molecules are one on the substrate surface when no voltage is applied. In this way, the pretilt angle is tilted and the homogenius is oriented.

In order to keep the liquid crystal layer 31 at a predetermined thickness, a spherical spacer having a diameter of 30 μm, which is not shown, is dispersed in an adhesive, and although not shown, the peripheral portion of each substrate is covered with an adhesive. The liquid crystal is sealed using.

As the transparent insulating film 41, a polymer film, a glass ribbon, or the like can be used. In Example 1, a photoresist (SU8) was used so as to have a predetermined thickness, but it should be used even if it is a transparent insulating material or a material having a large dielectric constant regardless of other organic or inorganic materials. Can be done.

Nine concentric electrode groups with a width of 90 μm and a spacing of 30 μm between each electrode are provided in a circular region having a diameter of about 2 mm, and a circular electrode having a diameter of 150 μm is provided in the center. A voltage of 0.87 V as V1 and a voltage of 2.8 V as V2 were applied between the central electrode 220 and the outer electrode 229 and the electrode 21 so that such a voltage was applied. Here, both V1 and V2 are sine waves of 1 kHz and have the same phase, and the threshold voltage of RDP85475, which is a liquid crystal material, is 0.864 V. Further, a semiconductor laser light (wavelength 0.589 nm) is used as a light source. Here, the sum of the widths of the concentric electrodes and the distance between the electrodes is 120 μm.

The liquid crystal optical device of the present application has a feature that it does not have a frequency characteristic because there is no resistance component such as a high resistance film between the electrode and the liquid crystal layer. The dielectric characteristics may change and frequency characteristics may occur, but when driven at a frequency of several tens of kHz or less, the frequency characteristics are not shown.

Regarding the optical phase difference distribution characteristics that occur in the liquid crystal layer when a liquid crystal cell having a simple configuration in which the transparent insulating layer 41 is removed from the configuration shown in FIG. 1 is manufactured and a voltage having the voltage distribution shown in FIG. 2 is applied. , The phase difference distribution characteristic in the cross section in the radial direction is shown in FIG. As can be seen from FIG. 3, it has a step-like complex optical phase difference distribution characteristic with a step-like voltage distribution and a maximum value corresponding to a decrease in the effective voltage in the gap separating each electrode, which is good. It has been difficult to construct a liquid crystal optical device having various optical characteristics. In this case, the sum of the thickness of the transparent insulating layer and the thickness of the liquid crystal layer is only the thickness of the liquid crystal layer, which is 30 μm.

Next, in the liquid crystal lens having the structure in which the transparent insulating layer 41 is provided as shown in FIG. 1, the value of the voltage distribution shown in FIG. 2 is set to the extent that the transparent insulating layer is inserted with the thickness of the transparent insulating layer being 20 μm. The optical phase difference distribution characteristics that occur in the liquid crystal layer when V1 is 1.4 V and V2 is 6.8 V are as shown in FIG. 4, and the sum of the thickness of the transparent insulating layer and the thickness of the liquid crystal layer is as shown in FIG. Is 50 μm, which is smaller than 120 μm, which is the sum of the width of the concentric electrodes and the distance between the electrodes. Therefore, in FIG. 4, the degree of unevenness is slightly smaller than that in FIG. 3, but the liquid crystal having good optical characteristics It was difficult to construct an optical device.

If the thickness of the transparent insulating layer 41 is further increased to 50 μm, the required values of V1 and V2 will be 2.3 V and 12.7 V, respectively, and the sum of the thickness of the transparent insulating layer and the thickness of the liquid crystal layer will be as large as 80 μm. The smoothing effect on the potential distribution gradually becomes more effective, and the disturbance of the step-like optical retardation distribution is alleviated, but the optical retardation distribution has the characteristic that the step-like disturbance remains as shown in FIG. rice field.

If the thickness of the transparent insulating layer 41 is further increased to 120 μm, the required values of V1 and V2 are 4.2 V and V2 is 25 V, respectively, but the sum of the thickness of the transparent insulating layer and the thickness of the liquid crystal layer is 150 μm. Since it is larger than 120 μm, which is the sum of the width of the concentric electrodes and the distance between the electrodes, the optical phase difference distribution characteristic generated in the liquid crystal layer is smooth as shown in FIG. A smooth, continuous parabolic phase difference distribution characteristic was obtained, and extremely good lens characteristics could be obtained.

A resistor adjusted so that the voltage of each electrode has a value as shown in FIG. 2 is connected between the electrode groups 220 to 229 in FIG. 1, but the circular electrode 220 at the center is the most connected. The resistance values of the transparent resistance film provided between the adjacent electrodes toward the external electrode 229 are 10 ohms, 10 ohms, 15 ohms, 30 ohms, 30 ohms, 45 ohms, 60 ohms, 120 ohms, and 240, respectively. It is an ohm, and the resistance value between the electrodes adjacent to the inside is equal to or larger than that from the center to the outside.

As shown in FIG. 2, the resistance value of the transparent resistance film provided between the electrodes adjacent to each of the electrodes adjacent to the central circular electrode 220 toward the outermost electrode 229 is shown in FIG. 2 for each electrode group. Since it changes in the same way as the voltage applied to each electrode of the electrode group, the resistance value of the transparent resistance film is the value of the step approximation of the value depending on the high-order function with the distance in the radial direction from the center as a variable. It has become. Here, the order of the higher-order function is preferably 4th or higher.

When the potential distribution, that is, the distribution of the resistance value of the transparent resistance film is expressed by a function whose variable is the distance in the radial direction from the center, the order is higher than the fourth order, and the optical characteristics of the lens are improved. It is possible to make a precise distribution shape. In FIG. 2, the potential distribution when a sixth-order function is used as an example is shown by a broken line, and an example of the function including the coefficient of each order is shown in the margin. Since the potential distribution curve is centrally symmetric, the odd-order coefficients of the function are omitted because they are extremely small values.

When the thickness of the transparent resistance film is constant and the distances between the concentric electrodes are equal, the resistance value of the transparent resistance film is inversely proportional to the width, so that the resistance value is directed outward in the radial direction from the center. By adjusting the width of the resistance film so that it is the reciprocal of the predetermined resistance value, the voltage distribution as shown in FIG. 2 can be obtained. Further, the reciprocal of the width of the resistance film can be set to be a step approximation value of a value depending on a higher-order function such as a quartic function or a sixth-order function.

In this embodiment, by providing a certain distance between the electrode group of the second substrate and the liquid crystal layer by the transparent insulating layer, the stepped voltage distribution is smoothed and the voltage smoothly distributed in the liquid crystal layer. Therefore, the optical phase difference distribution is also smoothed and smoothed, and good lens characteristics can be obtained. Furthermore, since there is only a transparent insulating layer between the electrode group and the liquid crystal layer and there is no other impedance layer or resistance layer, it basically does not depend on the frequency of the drive voltage, so it operates in a wide frequency range. It is possible.

The thicker the insulating layer, the greater the effect of smoothing the voltage distribution. On the other hand, the thicker the insulating film, the higher the driving voltage. Therefore, in order to perform low voltage driving, the width of the concentric electrodes and the adjacent electrodes It is desirable to reduce the thickness of the required insulating layer by narrowing the space between them, that is, by increasing the number of concentric electrodes.

Next, another embodiment will be described. For example, in the electrode configuration of FIG. 1, it is also possible to operate by applying V1 and a third voltage V3 independent of V2 to one concentric 224 located between the central circular electrode 220 and the outermost electrode 229. In that case, it is possible to form a more precise voltage distribution as compared with the case where the drive is performed only by the V1 and V2 voltages, and it is possible to construct a lens exhibiting good optical characteristics. Further, even when switching from a convex lens to a concave lens by exchanging the values of V1 voltage and V2 voltage, it is useful for adjusting the voltage distribution.

moreover. The condition that the resistance values (characterized by the above values) equal to or larger than the resistance values between the adjacent electrodes on the inner side become equal or larger from the center to the outer side, for example, 10 ohms, 10 ohms, and 15 ohms. The resistance distribution of ohms, 30 ohms, 30 ohms, 45 ohms, 60 ohms, 120 ohms, 240 ohms is reset once at the electrode that applies the V3 voltage, and the resistance values between the adjacent electrodes are equal or larger. Since the condition such that becomes can be set again from 10 ohms, the required resistance value can be set within the range that can be set even when the number of concentric electrodes increases and the ratio of the resistance values at both ends becomes very large. It has the advantage of facilitating the construction of the distribution.

Further, another embodiment will be described. Concentric circles with the same electrode width and distance between electrodes outside the inner liquid crystal optical device with a diameter of 10.8 mm using a central circular electrode with a diameter of 150 μm and concentric electrodes with a width of 100 μm and a spacing of 50 μm A liquid crystal optical device was produced by providing an electrode group consisting of shaped electrodes and using RDP85475 liquid crystal, which is the same liquid crystal material as in Example 1, with the thickness of the liquid crystal layer being 80 μm and the thickness of the transparent insulating layer being 80 µ m.

Here, a portion provided with an electrode group consisting of concentric electrodes on the outside of the inner liquid crystal optical device is referred to as a Fresnel portion. In the third embodiment, the liquid crystal optical device has a Fresnel structure and has one Fresnel portion. The voltage applied to the central electrode is V1, the voltage applied to the outermost electrode of the inner optical device is V2, the voltage applied to the innermost side of the Fresnel portion is V3, and the voltage applied to the outermost electrode is V4. For the manufactured liquid crystal optical device, a voltage is applied to and held on the electrodes under the following conditions, the optical phase difference distribution characteristics are measured, and the optical phase difference distribution characteristics are shown in FIG. 7 (A). FIG. 7B shows a characteristic in which the distribution characteristic of the above is roughly expressed as a characteristic obtained by extrapolating the optical phase difference distribution characteristic of the liquid crystal optical device. This Fresnel-structured liquid crystal optical device exhibits the characteristics of a convex lens having an aperture of 15.4 mm and a lens power of 1.23 diopters.
(conditions)
Frequency = 1kHz
V1 = 2.2V
V2 = 16.0V
V3 = 2.2V
V4 = 16. V

In Example 1, by increasing the thickness of the transparent insulating layer 41 to 120 μm with the liquid crystal lens having the electrode configuration shown in FIG. 1, the smooth optical phase difference distribution characteristic as shown in FIG. 6 can be obtained, but V1 Needed 4.2V and V2 needed 25V. In Example 3, the V1 voltage is as low as 2.2 V and the V2 voltage is as low as 16 V by narrowing the concentric electrode width to 80 μm and the electrode spacing to 40 μm to reduce the thickness of the transparent insulating layer to 80 μm. However, it is desirable to further reduce the voltage V2 on the high voltage side.

The voltage on the high voltage side is obtained by reducing the thickness of the transparent insulating layer 41, that is, reducing the sum of the width of the concentric electrodes and the distance between adjacent electrodes, specifically, increasing the number of concentric electrodes. Although it can be lowered, the voltage V2 on the high voltage side can be lowered by arranging the outermost electrode 220 to which the voltage V2 on the high voltage side is applied close to the liquid crystal layer side.

In FIG. 8, in the electrode structure shown in FIG. 1, the central electrode and the outermost electrode are arranged on the liquid crystal layer side of the transparent insulating layer, and arranged on the liquid crystal layer side and the liquid crystal layer side. It is a block diagram which shows one Embodiment of the liquid crystal optical device which operates by applying a voltage between the concentric electrode adjacent to the electrode and the electrode of the 1st substrate.

In FIG. 8, the central electrode and the outermost electrode are arranged on the liquid crystal layer side of the transparent insulating layer, but when the liquid crystal optical device operates as a convex lens, the outermost concentric electrode applies the highest voltage. Therefore, it will be placed on the liquid crystal layer side, but when operating as a concave lens, the highest voltage will be applied to the innermost center electrode, so in any case the operating voltage can be lowered. The state where these electrodes are arranged on the liquid crystal layer side is shown.

A liquid crystal optical device having the same structure as that of Example 1 and having an electrode structure as shown in FIG. 8 was produced. That is, the liquid crystal layer thickness is 30 μm, the transparent insulating layer thickness is 120 μm, the width of the concentric electrodes is 90 μm, and the electrode spacing is 30 μm. When the central electrode and the outermost electrode are placed in the middle of the transparent insulating layer, that is, at a position 60 μm from the liquid crystal layer side, the highest voltage applied to the outermost side of the concentric electrode changes from 25V to 12V, and further placed on the liquid crystal layer side. Then, it was possible to reduce the voltage to 2.3V.

When there is a gap between the electrode arranged on the liquid crystal layer side and the concentric electrode adjacent to the electrode arranged on the liquid crystal layer side, the electric field distribution applied to the liquid crystal layer may be disturbed. Since this may adversely affect the optical phase difference distribution characteristics, it is preferable to slightly expand the concentric electrodes adjacent to the electrodes arranged on the liquid crystal layer side so that these electrodes overlap each other.

Aiming at the realization of a liquid crystal optical device capable of large diameter and low voltage drive, the Frenel portion of the Frenel structure liquid crystal optical device shown in Example 3 has a three-stage structure, and is further centered as shown in Example 4. A pair of the outermost concentric electrodes in the liquid crystal optical device and the innermost concentric electrodes of the electrode group of the Frenel portion arranged outside the concentric electrodes, and each concentric electrode arranged outside the outermost concentric electrodes. The outermost electrode of the electrode group and the innermost electrode of the Frenel part electrode group arranged on the outer side of the electrode group, and the adjacent outermost and innermost electrode pairs of each adjacent electrode group and the outermost of the whole. A liquid crystal optical device in which the electrodes were arranged at a position of 10 µ m from the liquid crystal layer side in the transparent insulating layer was produced.

Here, the RDP85475 liquid crystal is used as in the other examples, the liquid crystal layer thickness is 100 μm, the transparent insulating layer thickness is 80 μm, the width of the concentric electrodes is 100 μm, the electrode spacing is 50 μm, and the diameter of the central liquid crystal optical device. Is 9.9 mm, and the diameter of the entire liquid crystal optical device is 19.6 mm. Here, as described in Example 4, the widths of the concentric electrodes adjacent to the electrodes arranged on the liquid crystal layer side are slightly widened so that these electrodes overlap each other.

In the electrode structure shown in FIG. 8, the voltages V1 and V2 applied to each electrode. The voltage applied to V3, V4 and the innermost electrode of each frennel portion and the adjacent electrode is V5, V6, and the voltage applied to the outermost electrode and the adjacent electrode of each frennel portion is V4, V3. A voltage was applied to and held on the electrodes of the manufactured liquid crystal optical device under the following conditions, and the optical phase difference distribution characteristics were measured. (conditions)
V1 = 1.02V
V2 = 2.00V
V3 = 14.00V
V4 = 3.40V
V5 = 1.02V
V6 = 1.40V
And said. Here, the frequencies are all 1 kHz.

The optical phase difference distribution characteristics are shown in FIG. 9A so that the distribution characteristics of the optical phase difference in each adjacent Fresnel portion are the characteristics obtained by extrapolating the optical phase difference distribution characteristics of the liquid crystal optical device at the approximate center. It is shown in FIG. 9 (B). We were able to realize a liquid crystal optical device with an overall lens power of about 2 diopters.

The drive voltage can be reduced most if the transparent insulating layer between the electrode arranged on the liquid crystal layer side and the liquid crystal layer is eliminated so that the electrode is in contact with the liquid crystal layer only through the alignment film. Due to the sudden change in the potential distribution between them, a region called dispersion, in which the molecular orientation is reversed, may appear and the optical characteristics may deteriorate. This effect becomes remarkable in the region where the direction in which the liquid crystal molecules rise with respect to the substrate surface and the force exerted by the orientation effect of the liquid crystal molecules due to the electric field are opposite to each other.

In the liquid crystal optical device having the same structural dimensions as in the fifth embodiment, the outermost concentric electrodes in the central liquid crystal optical device and the concentric electrodes in the frennel portion adjacent to the innermost and outermost concentric electrodes in each frennel portion. A liquid crystal optical device having a region in which liquid crystal molecules are oriented perpendicular to the electrode substrate surface was produced. In this device, it is possible to suppress the generation of a region where the molecular orientation is reversed, which is called dispersion, so that a liquid crystal optical device having good optical characteristics can be configured. Similarly, by providing a partition wall instead of the vertically oriented region, it is possible to suppress the occurrence of such a region where the molecular orientation is reversed, which is called dispersion.

In the liquid crystal optical device having the same structural dimensions as in Example 1, a liquid crystal optical device in which the orientation direction of the liquid crystal molecules is axially symmetric, that is, concentric circles is produced. The optical characteristics of this device are almost the same as those of the device of Example 1, but by making such an orientation, a transparent state that does not depend on a specific deflection direction in one liquid crystal layer and a variable focal length on the convex lens side and the concave lens side. It has characteristics, and when combined with a fixed focal length lens, it is possible to construct a switchable trifocal lens having a fixed focal length and two sets of variable focal length characteristics.

The alignment state of the liquid crystal molecules may be not only concentric circles but also radial orientation states, or may be an orientation state such as a checkered pattern in which regions whose orientation directions are orthogonal to each other are alternately arranged, and further, in various directions. It may be a combination of oriented regions.

The concentric orientation state can be easily obtained by rotating the substrate and rubbing it concentrically. In addition, other alignment states can be produced by using a photo-alignment technique. In a device in which the liquid crystal molecules are oriented concentrically, the direction of the pretilt and the rising direction of the liquid crystal molecules due to the electric field are always orthogonal to each other, so that the occurrence of dispersion can be suppressed.

Further, instead of the transparent centrally symmetric electrode group, a plurality of transparent strip-shaped electrodes extending in one direction are arranged on the second substrate surface, and the common first electrode arranged on the first substrate is used. By applying a stepped voltage between each band-shaped electrode so that the optical phase difference distribution characteristic changes linearly, an optical device having a function of deflecting the direction of incident light is realized. be able to.

As in the other examples, the RDP85475 liquid crystal display was used, the liquid crystal layer thickness was 30 μm, the transparent insulating layer thickness was 60 μm, the band-shaped electrode width was 45 μm, the electrode spacing was 15 μm, and the opening width was 0.57 mm. Further, a transparent resistance film is connected from the band-shaped electrodes at both ends to the band-shaped electrodes at the other ends via the adjacent band-shaped electrodes, and 1 is provided between the band-shaped electrodes at both ends and the first electrode serving as a common electrode. When a voltage of .5V or 15V was applied, an optical deflection device having a deflection angle of about 1 degree could be obtained.

In this case as well, the sum of the thickness of the transparent insulating layer and the thickness of the liquid crystal layer is set to 90 μm, and the sum of the electrode width and the electrode spacing is set to 60 μm. Has been obtained.

The resistance value of the transparent resistance film placed between each electrode of the transparent band-shaped electrode group is a value that depends on a function of approximately third order or higher with the distance from one band-shaped electrode toward the other end as a variable, or a step approximation thereof. When the value of is set to, a linear optical phase difference distribution characteristic can be obtained.

Further, the effective aperture width can be widened by forming the Fresnel structure in which a plurality of the above-mentioned liquid crystal light deflection devices are arranged. A liquid crystal light deflection device having a Fresnel structure was prepared by arranging five liquid crystal light deflection devices having an aperture width of 0.57 mm. In this case, the opening width was 2.85 mm and the deflection angle was about 1 degree.

Further, the driving voltage can be lowered by arranging the electrodes at the boundary of each Fresnel portion on the liquid crystal side of the transparent insulating layer. When the electrode was placed at a position of 15 µ m from the liquid crystal layer in the transparent insulating layer, the highest voltage value of 15V became 4V, and the drive voltage could be lowered.

According to the present invention, since there is no transparent high resistance layer or impedance layer between the drive electrode and the liquid crystal layer, stable operation for a long period of time is realized regardless of the frequency of the drive voltage. Further, the optical phase difference distribution characteristic becomes smooth, and it can be applied not only to a large-diameter liquid crystal lens and a light deflection device having excellent optical characteristics, but also to various optical devices and the like.

Further, the present invention is not limited to the above-described embodiment as it is, and at the implementation stage, the components can be modified and mimicked within a range that does not deviate from the gist thereof. In addition, various inventions can be formed by appropriately combining the plurality of components disclosed in the above embodiment. For example, some components may be removed from the components shown in the embodiments, or components spanning different embodiments may be combined as appropriate.

The liquid crystal optical device of the present invention realizes a device capable of adjusting the optical lens characteristics and the aberration of the optical system by variably controlling the effective refractive index of the liquid crystal by applying a voltage between the electrodes. Since the drive voltage does not depend on frequency, it can be used for various lenses such as small lenses, medium-sized and large lenses.

11 ... 1st substrate, 12 ... 2nd substrate, 21 ... common electrode, 220 ... central circular electrode, 221 to 229 ... concentric electrode group, 31 ... -Liquid crystal layer, 41 ... Transparent insulating layer, 81, 82, 83, 84 ... Drive power supply

As a varifocal lens using a liquid crystal, a liquid crystal layer is inserted between a flat plate-shaped first electrode and a second transparent electrode having a patterned electrode having a circular opening, and the second transparent electrode is used. By inserting a transparent insulating layer between the liquid crystal layer and arranging the second transparent electrode at a certain distance from the liquid crystal layer, axial symmetry is applied even if the diameter of the opening portion of the electrode is increased to some extent. Patent Document 1 proposes a method in which the non-uniform electric field of No. 1 spreads to the vicinity of the center of the opening and the effective refractive index of the liquid crystal with respect to the incident light is changed to exhibit a good lens effect. A liquid crystal lens of about several mm has been reported.

A transparent resistance film adjusted so that the voltage of each electrode has a value as shown in FIG. 2 is connected between the electrode groups 220 to 229 in FIG. 1, and the transparent resistance is described. When the thickness of the film is constant and the spacing between the concentric electrodes is equal, the resistance value of the transparent resistance film is inversely proportional to its width, so that a predetermined resistance is applied radially outward from the center. The width of the resistance film was adjusted so that it was the reciprocal of the value. That is, the resistance values of the transparent resistance film provided between the adjacent electrodes from the central circular electrode 220 toward the outermost electrode 229 are 10 ohms, 10 ohms, 15 ohms, 30 ohms, and 30 ohms, respectively. The resistance values are 45 ohms, 60 ohms, 120 ohms, and 240 ohms, and the resistance values between the electrodes adjacent to the inner side are equal to or larger than the resistance values from the center to the outside.

The resistance value of the transparent resistance film provided between the adjacent electrodes from the central circular electrode 220 toward the outermost electrode 229 shall change in the same manner as the voltage applied to each of the electrodes shown in FIG. Therefore, the resistance value of the transparent resistance film is a step approximation value of a value depending on a high-order function whose variable is the distance in the radial direction from the center. Here, the order of the higher-order function is preferably 4th or higher.

As described above, when the thickness of the transparent resistance film is constant and the distance between the concentric electrodes is equal, the resistance value of the transparent resistance film is inversely proportional to the width, so that the radius from the center. The voltage distribution as shown in FIG. 2 can be obtained by adjusting the width of the resistance film so as to be the reciprocal of a predetermined resistance value toward the outside in the direction. Further, the reciprocal of the width of the resistance film can be set to be a step approximation value of a value depending on a higher-order function such as a quartic function or a sixth-order function.

Further, another embodiment will be described. An electrode width outside the inner liquid crystal optical device consisting of a first group of electrodes with a diameter of 10.8 mm using a central circular electrode with a diameter of 150 μm and concentric electrodes with a width of 100 μm and a spacing of 50 μm. A second electrode group consisting of concentric electrodes having the same spacing between the electrodes is provided, and the RDP85475 liquid crystal, which is the same liquid crystal material as in Example 1, is used, the thickness of the liquid crystal layer is 80 μm, and the thickness of the transparent insulating layer is 80 μm . As a liquid crystal optical device was manufactured.

Here, a portion provided with a second electrode group composed of concentric electrodes having the same center on the outside of the inner liquid crystal optical device will be referred to as a Fresnel portion. In the third embodiment, the liquid crystal optical device has a Fresnel structure and has one Fresnel portion. The voltage applied to the central electrode is V1, and the voltage applied to the outermost electrode of the optical device consisting of the inner first electrode group is V2, and the voltage applied to the innermost electrode of the Frenel portion composed of the second electrode group is applied. The voltage is V3, the voltage applied to the outermost electrode of the Fresnel portion is V4, and the voltage is applied and held to each electrode under the following conditions for the manufactured liquid crystal optical device, and the optical phase difference distribution characteristic is measured. The optical phase difference distribution characteristic is shown in FIG. 7A, and the characteristic is shown so that the distribution characteristic of the optical phase difference of the Fresnel portion is a characteristic obtained by extrapolating the optical phase difference distribution characteristic of the liquid crystal optical device. 7 (B) is shown. This Fresnel-structured liquid crystal optical device exhibits the characteristics of a convex lens having an aperture of 15.4 mm and a lens power of 1.23 diopters.
(conditions)
Frequency = 1kHz
V1 = 2.2V
V2 = 16.0V
V3 = 2.2V
V4 = 16. V

Aiming at the realization of a liquid crystal optical device capable of large diameter and low voltage drive, the Frenel portion of the Frenel structure liquid crystal optical device shown in Example 3 has a three-stage structure, and further, as shown in Example 4, the first A first Frenel section consisting of a central electrode and an outermost concentric electrode in a central liquid crystal optical device consisting of a set of electrodes , and a second set of concentric electrodes having the same center arranged outside the center electrode and the outermost concentric electrodes. The innermost concentric electrode of the second Frenel portion consisting of the innermost concentric electrode , the outermost concentric electrode, and the third set of electrodes having the same center arranged outside the concentric electrode. The innermost electrode and the outermost electrode of the third Frenel portion consisting of the electrode, the outermost electrode, and the fourth set of electrodes having the same center arranged outside the electrode and the outermost electrode are placed in the transparent insulating layer. A liquid crystal optical device arranged at a position of 10 μm from the liquid crystal layer side was manufactured.

Claims (7)

A liquid crystal layer in which liquid crystal molecules contained between a first substrate having a transparent electrode and a second substrate having a transparent electrode are oriented, and the transparent electrode on the surface of at least the second substrate is provided. Each is formed from a center electrode held at a stepped voltage and a group of concentric electrodes.
A transparent insulating layer is arranged between the center electrode, a plurality of concentric electrodes, and the liquid crystal layer, and the center electrode, the concentric electrodes, and the transparent electrode of the first substrate face each other. A liquid crystal optical device that operates by adjusting the distribution of the effective refractive electrode of the liquid crystal layer in each region.
Liquid crystal optics characterized in that the sum of the thickness of the transparent insulating layer and the thickness of the liquid crystal layer is larger than the sum of the average values of the widths of the concentric electrodes and the average value of the intervals between the electrodes and other electrodes adjacent to the electrodes. device. In the liquid crystal optical device according to claim 1, an independent voltage is applied between each of the central electrode and the outermost electrode and the electrode of the first substrate, and the outermost electrode is applied from the central electrode via the adjacent electrode. The electrodes are connected by a transparent resistance film, and as the resistance value of the transparent resistance film moves from the center to the outside, the resistance values between the electrodes adjacent to the inside are equal to or larger than each other. A liquid crystal optical device characterized by being present. The liquid crystal optical device according to claim 2, wherein the resistance value of the transparent resistance film is a value depending on a function of approximately 4th order or higher having a distance from the center as a variable or a value approximated by a step thereof. Liquid crystal optical device. In any of the liquid crystal optical devices according to claims 1 to 3, at least one set of a plurality of electrodes is formed by setting a plurality of concentric transparent electrodes as a set outside the outermost concentric electrodes. Liquid crystal optics is characterized in that a group is arranged and the liquid crystal optics operates by applying a voltage such that the distribution characteristic of the optical phase difference in each adjacent set is a characteristic obtained by extrapolating the optical phase difference distribution characteristic of the liquid crystal optical device. device In any of the liquid crystal optical devices according to claims 1 to 3, the central electrode and the outermost concentric electrode or any one of the electrodes are arranged between the electrode group and the liquid crystal layer. It is arranged in the insulating layer or on the liquid crystal layer side of the transparent insulating layer.
Electrodes arranged in the transparent insulating layer or on the liquid crystal layer side of the transparent insulating layer and electrodes other than the electrodes are arranged in the transparent insulating layer or on the liquid crystal layer side of the transparent insulating layer. A liquid crystal optical device characterized in that it operates by further applying a voltage between a concentric electrode adjacent to the electrode and an electrode of a first substrate. In the liquid crystal optical device according to claim 5, at least one set of electrode groups is arranged with a plurality of concentric transparent electrode groups as a set outside the outermost concentric electrodes.
A pair of the outermost concentric electrodes and the innermost concentric electrodes of the set of electrodes arranged outside the concentric electrodes, and each concentric electrode arranged outside the outermost concentric electrodes. The outermost electrode of the group, the innermost electrode pair of the electrode group arranged outside the group, the adjacent outermost and innermost electrode pairs of each adjacent electrode group, and the outermost electrode of the whole are transparent. It is arranged in the insulating layer or on the liquid crystal layer side of the transparent insulating layer.
Between the electrodes arranged in the transparent insulating layer or on the liquid crystal layer side of the transparent insulating layer, and the electrodes other than the electrodes and concentric electrodes adjacent to the electrodes, and the electrodes of the first substrate. A liquid crystal optical device characterized in that it operates by applying a voltage to the
A liquid crystal optical device characterized in that it operates by applying a voltage such that the distribution characteristic of the optical phase difference in each set of adjacent electrodes is a characteristic obtained by extrapolating the optical phase difference distribution characteristic of the liquid crystal optical device at the center. .. The transparent electrode is provided with a liquid crystal layer in which liquid crystal molecules accommodated between the first substrate having a transparent electrode and the second substrate having a transparent electrode are oriented, and the transparent electrode is at least on the surface of the second substrate. Each is formed from a group of strip-shaped electrodes extending in one direction, each held at a stepped voltage.
A transparent insulating layer is arranged between the transparent electrode group and the liquid crystal layer, and the liquid crystal layer is formed in each region where the transparent electrode group and the transparent electrode of the first substrate face each other. A liquid crystal optical device that operates by adjusting the effective refractive electrode distribution.
The feature is that the sum of the thickness of the transparent insulating layer and the thickness of the liquid crystal layer is larger than the sum of the average values of the widths of the electrodes of the transparent strip-shaped electrode group and the average value of the intervals between the transparent strip-shaped electrodes adjacent to the electrodes. Liquid crystal optical device.

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