JP6128719B1 - LCD lens - Google Patents

Abstract

A liquid crystal lens having an enlarged effective lens diameter is disclosed. A first transparent electrode layer, a second transparent electrode layer, a liquid crystal layer provided between the first transparent electrode layer and the second transparent electrode layer, and the second transparent electrode layer. An insulating layer provided between the electrode layer and the liquid crystal layer, and a high resistance layer provided between the insulating layer and the liquid crystal layer, and the second transparent electrode layer in plan view, A center electrode layer having a circular shape and a plurality of annular electrode layers provided around the center electrode layer and spaced apart from the center electrode layer. A first resistance layer having a shape, and the outer edge of the high resistance layer is present inside the outer edge of the outermost annular electrode layer among the plurality of annular electrode layers in a plan view. And a liquid crystal lens. [Selection] Figure 1

Description

  The present application discloses a liquid crystal lens.

  Liquid crystal molecules exhibiting dielectric anisotropy and optical anisotropy can control the orientation direction of the liquid crystal molecules by controlling the applied voltage, and the effective refractive index can be continuously varied. For example, by providing a layer (liquid crystal layer) containing liquid crystal molecules as a medium between a first transparent electrode and a second transparent electrode, and controlling the voltage between the electrodes, the effective refractive index distribution of the liquid crystal layer can be obtained. It can be adjusted and can function as a liquid crystal lens.

  For example, the above-mentioned second transparent electrode (concentric pattern electrode group) is constituted by a circular center electrode layer and a plurality of annular electrode layers provided around the center electrode layer. By forming a voltage distribution in the radial direction, a refractive index distribution can be generated in the radial direction also in the liquid crystal layer, and the liquid crystal lens can function as, for example, a refractive index distribution type lens. However, in a liquid crystal lens using such a second transparent electrode, the voltage applied to the liquid crystal layer is stepped and does not have a continuous and smooth potential distribution. Therefore, the refractive index distribution in the liquid crystal layer is also a discontinuous stepped shape, which is not an ideal lens characteristic. In order to solve such a problem, in the liquid crystal lens disclosed in Patent Document 1, a double layer of an insulating layer and a high resistance layer is disposed between the second transparent electrode and the liquid crystal layer, whereby the liquid crystal layer The refractive index distribution is continuous and smooth.

JP 2012-137682 A

  In the liquid crystal lens disclosed in Patent Document 1, a double layer of an insulating layer and a high resistance layer is configured to cover the entire surface of the liquid crystal layer. That is, the area of the high resistance layer is made larger than the area of the second transparent electrode (pattern electrode group) in plan view. According to the knowledge of the present inventors, when a high resistance layer having such a large area is provided, when a voltage is applied between the first and second transparent electrodes, the second transparent electrode layer is seen in plan view. Even on the outside, an electric field is induced by the high resistance layer, and as a result, the inclination of the liquid crystal molecules in the liquid crystal layer changes. In such a case, the liquid crystal molecules inside the second transparent electrode layer are also oriented in an unintended direction by being dragged by the orientation of the liquid crystal molecules outside the second transparent electrode layer in plan view. That is, in the vicinity of the outer edge of the second transparent electrode layer, the liquid crystal molecules cannot be aligned in the intended direction, and the optical phase difference distribution does not have a parabolic cross section, resulting in a small effective lens diameter of the liquid crystal lens. turn into.

  In view of the above-described background art, the present application discloses a liquid crystal lens that maintains an excellent lens characteristic and realizes an increase in effective lens diameter and an increase in effective lens power.

This application is one of the means for solving the above-described problems.
A first transparent electrode layer; a second transparent electrode layer; a liquid crystal layer provided between the first transparent electrode layer and the second transparent electrode layer; the second transparent electrode layer; An insulating layer provided between the liquid crystal layers, and a high resistance layer provided between the insulating layer and the liquid crystal layer, and the second transparent electrode layer has a circular center in plan view An electrode layer and a plurality of annular electrode layers provided around the center electrode layer so as to be separated from the center electrode layer, wherein the high resistance layer has a circular first shape in plan view. A liquid crystal lens, wherein, in a plan view, an outer edge of the high-resistance layer is present inside an outer edge of the outermost annular electrode layer of the plurality of annular electrode layers. Disclose.

The “transparent electrode layer” is a layer capable of transmitting light and functioning as an electrode, and may be the same as the transparent electrode layer conventionally used for liquid crystal lenses. For example, a transparent electrode layer containing ITO, titanium oxide, zinc oxide or a mixture thereof can be used.
The “liquid crystal layer” may be any layer that can adjust the orientation of the liquid crystal by controlling the voltage of the transparent electrode layer and adjust the effective refractive index distribution. Usually, it refers to a layer in which liquid crystal is filled between the alignment film.
The “insulating layer” refers to a layer that can transmit light and is made of an insulating material. The insulating material may be organic or inorganic. Alternatively, it may be a layer made of a material that can transmit light and has a higher dielectric constant than the following high resistance layer.
The “high resistance layer” refers to a layer that can transmit light and has a sheet resistance of 1 kΩ to 10 GΩ.
“Plan view” means “view from above” when the second transparent electrode layer is on the upper side and the first transparent electrode layer is on the lower side.
“A plurality of annular electrode layers provided around the central electrode layer and spaced apart from the central electrode layer” means that one annular electrode layer is formed around the central electrode layer via a ring-shaped gap. This means that another annular electrode layer is provided around the one annular electrode layer via a ring-shaped gap. The number of annular electrode layers may be plural (two or more). Thus, in the liquid crystal lens of the present disclosure, the second transparent electrode layer constitutes a concentric pattern electrode group.
The “outer edge of the high-resistance layer” refers to the outer edge of the first resistance layer when the high-resistance layer is composed only of the first resistance layer. The high-resistance layer is the first resistance layer and the other resistance layers. When composed of a resistance layer (for example, the following second resistance layer), it means the outer edge of the outermost resistance layer among the plurality of resistance layers.
“The outer edge of the high-resistance layer exists inside the outer edge of the outermost annular electrode layer of the plurality of annular electrode layers”, in other words, in the plan view, the outermost annular zone It means that the outer edge of the high resistance layer is located inside the outer edge of the electrode layer.

  In the liquid crystal lens of the present disclosure, it is preferable that an outer edge of the first resistance layer is present in any one of the plurality of annular electrode layers in a plan view.

  “Within the band width” means between the outer edge and the inner edge of the annular electrode layer. That is, “in the plan view, the outer edge of the first resistance layer exists within the width of any one of the plurality of annular electrode layers” in the plan view. This means that the outer edge of this is located between the outer edge and the inner edge of one annular electrode layer.

  In the liquid crystal lens according to the present disclosure, in a plan view, the high resistance layer has an annular shape in which the first resistance layer and the first resistance layer are separated from the first resistance layer. And a second resistance layer. In the case of such a form, as described above, the liquid crystal lens has an outer edge of the second resistance layer that is more than the outer edge of the outermost annular electrode layer of the plurality of annular electrode layers in plan view. Exists inside.

  In the case of such a form, it is preferable that the liquid crystal lens has an outer edge of the second resistance layer in a band width of any one of the plurality of annular electrode layers in plan view.

  Further, in such a form, the liquid crystal lens has a third resistance in which the high resistance layer is provided around the second resistance layer and separated from the second resistance layer in plan view. A layer may be provided. Needless to say, the outer edge of the third resistance layer also exists inside the outer edge of the outermost annular electrode layer. The third resistance layer may be composed of a plurality of resistance layers.

  In the liquid crystal lens of the present disclosure, a part of the plurality of annular electrode layers may be an open circuit. That is, some annular electrode layers may be opened without being electrically connected.

  In the liquid crystal lens of the present disclosure, some liquid crystal molecules in the liquid crystal may be aligned in a direction different from other liquid crystal molecules by a vertical alignment film.

  In the liquid crystal lens according to the present disclosure, it is preferable that each of the plurality of annular electrode layers has a band width characterized in that the impedance is approximately the same.

“The impedance is about the same” means that the ratio (Ω ₁ / Ω ₂ ) of the impedance (Ω ₁ ) of _one annular electrode layer to the impedance (Ω ₂ ) of another annular electrode layer is 0.99 or more It means being within the range of 1.01 or less.

  In the liquid crystal lens of the present disclosure, the second transparent electrode layer includes the center electrode layer, the plurality of annular electrode layers, and an outermost transparent electrode provided around the annular electrode layer in the plan view. And a layer.

  Note that the liquid crystal lens of the present disclosure can be driven as follows, for example.

  That is, the liquid crystal lens of the present disclosure can be driven by a liquid crystal lens driving method that controls the frequency of a voltage applied to one or more of the plurality of annular electrode layers.

  Alternatively, the liquid crystal lens of the present disclosure can be driven by a liquid crystal lens driving method that controls the phase of an AC voltage applied to one or more of the plurality of annular electrode layers.

  In the liquid crystal lens of the present disclosure, the outer edge of the high-resistance layer exists inside the outer edge of the outermost annular electrode layer among the plurality of annular electrode layers in plan view. In such a case, it is possible to suppress the generation of an electric field outside the annular electrode layer in plan view, and it is possible to suppress a change in the orientation of the liquid crystal molecules in the liquid crystal layer. That is, the change in the orientation of the liquid crystal molecules outside the annular electrode layer does not adversely affect the orientation of the liquid crystal molecules inside the annular electrode layer. As a result, inside the annular electrode layer, the liquid crystal molecules in the liquid crystal layer can be aligned in the intended direction, keeping the characteristics of the liquid crystal lens in good condition and effectively expanding the effective lens diameter of the liquid crystal lens And effective lens power can be increased.

1 is a schematic cross-sectional view showing a configuration of a liquid crystal lens 10. 3 is a schematic plan view comparing a planar shape of a second transparent electrode layer 2 with a planar shape of a high resistance layer 5. FIG. It is a cross-sectional schematic diagram which shows the structure of a liquid-crystal layer. It is a figure for demonstrating the optical phase difference distribution of a liquid crystal lens. 2 is a schematic cross-sectional view showing a configuration of a liquid crystal lens 20. FIG. 3 is a schematic plan view comparing the planar shape of a second transparent electrode layer 2 with the planar shape of a high resistance layer 15. FIG. 2 is a schematic cross-sectional view showing a configuration of a liquid crystal lens 30. FIG. 3 is a schematic plan view comparing a planar shape of a second transparent electrode layer 22 with a planar shape of a high resistance layer 25. FIG. 4 is a diagram for explaining an optical phase difference distribution of a liquid crystal lens 30. FIG. 2 is a schematic cross-sectional view showing a configuration of a liquid crystal lens 40. FIG. 3 is a schematic plan view showing a configuration of a transparent electrode layer 32. FIG. It is a cross-sectional schematic diagram which shows the structure of the liquid crystal layer in the outermost ring electrode layer vicinity. 6 is a schematic cross-sectional view illustrating a configuration of a liquid crystal lens according to Comparative Example 1. FIG. 6 is a diagram illustrating an optical phase difference distribution of a liquid crystal lens according to Comparative Example 1. FIG. 6 is a schematic cross-sectional view illustrating a configuration of a liquid crystal lens according to Comparative Example 2. FIG. 6 is a diagram illustrating an optical phase difference distribution of a liquid crystal lens according to Comparative Example 2. FIG. 6 is a diagram illustrating an optical phase difference distribution of the liquid crystal lens according to Example 1. FIG.

1. Liquid crystal lens 10
FIG. 1 schematically shows a layer structure of the liquid crystal lens 10. FIG. 2 schematically shows the planar shapes of the second transparent electrode layer 2 and the high resistance layer 5 provided in the liquid crystal lens 10.

As shown in FIG. 1, the liquid crystal lens 10 is provided between the first transparent electrode layer 1, the second transparent electrode layer 2, and the first transparent electrode layer 1 and the second transparent electrode layer 2. A liquid crystal layer 3, an insulating layer 4 provided between the second transparent electrode layer 2 and the liquid crystal layer 3, and a high resistance layer 5 provided between the insulating layer 4 and the liquid crystal layer 3. Yes. As shown in FIG. 2, in the liquid crystal lens 10, the second transparent electrode layer 2 is separated from the circular center electrode layer 2a and the center electrode layer 2a around the center electrode layer 2a in plan view. The plurality of annular electrode layers 2b ₁ , 2b ₂ ,... Are provided, and the high resistance layer 5 includes a circular first resistance layer 5a in plan view. Further, as shown in FIG. 2, the liquid crystal lens 10 has an outer edge of the high resistance layer 5 (that is, an outer edge of the first resistance layer 5 a) in a plan view, and a plurality of annular electrode layers ₂ b ₁ , ₂ b ₂ , ... it is present inside the outer edge of the outermost annular electrode layer 2b ₅ of.

1.1. First transparent electrode layer 1
The first transparent electrode layer 1 is a layer capable of transmitting light and functioning as an electrode, and may be the same as the transparent electrode layer conventionally used for liquid crystal lenses. For example, a transparent electrode layer containing ITO, titanium oxide, zinc oxide or a mixture thereof can be used. The shape of the 1st transparent electrode layer 1 is not specifically limited, What is necessary is just a shape which opposes the 2nd transparent electrode layer 2 mentioned later through the liquid crystal layer 3. FIG. In particular, it is preferable to have a planar shape that covers the entire surface of the liquid crystal layer 3.

1.2. Second transparent electrode layer 2
The second transparent electrode layer 2 includes a circular center electrode layer 2a in plan view, and a plurality of annular electrode layers 2b ₁ provided around the center electrode layer 2a and spaced apart from the center electrode layer 2a, 2b ₂ ,... That is, in the second transparent electrode layer 2, one annular electrode layer 2 b ₁ is provided around the center electrode layer 2 a via a ring-shaped gap, and the one annular electrode layer 2 b ₁ Around the periphery, another annular electrode layer 2b ₂ is provided via a ring-shaped gap. The number of annular electrode layers 2b may be plural (two or more). The greater the number of annular electrode layers 2b, the better the lens characteristics of the liquid crystal lens. Thus, in the liquid crystal lens 10, the second transparent electrode layer 2 constitutes a concentric pattern electrode group. Such a transparent electrode layer itself is publicly known and may be the same as the pattern electrode group conventionally used for the liquid crystal lens.

1.3. Liquid crystal layer 3
The liquid crystal layer 3 may be a layer that can adjust the orientation of the liquid crystal by controlling the voltage of the transparent electrode layers 1 and 2 and that can adjust the effective refractive index distribution, and has been conventionally used for a liquid crystal lens. The same liquid crystal layer may be used. For example, as shown in FIG. 3, the liquid crystal layer 3 is formed by filling liquid crystal molecules 3a between alignment films 3b and 3b.

  The kind of the liquid crystal molecules 3a is not particularly limited. What is necessary is just to make it the same as the liquid crystal molecule conventionally used in the liquid crystal lens. The description is omitted here.

  The alignment film 3b is usually rubbed in one direction, and the director corresponding to the major axis direction of the liquid crystal molecules 3a is aligned at a predetermined pretilt angle. Such an alignment film 3b may be a conventional alignment film. For example, an alignment film made of polyimide is used.

1.4. Insulating layer 4
The insulating layer 4 may be any layer that can transmit light and is made of an insulating material. The insulating material may be organic or inorganic. Examples of the organic insulating material include a polymer resin. Examples of the inorganic insulating material include silicon dioxide (SiO ₂ ). Alternatively, the insulating layer 4 may be a layer made of a material that can transmit light and has a dielectric constant larger than that of the high resistance layer 5 described below. The surface shape of the insulating layer 4 is not particularly limited. For example, when the liquid crystal lens 10 is applied to a spectacle lens, the surface shape can cover the entire second transparent electrode layer 2. The thickness condition of the insulating layer 4 is not particularly limited as long as electrical insulation is maintained between the electrode layer and the high resistance layer. For example, the liquid crystal lens 10 is applied to a spectacle lens. In this case, the thickness can be 0.1 μm or more and 5 μm or less. By interposing the insulating layer 4 between the second transparent electrode layer 2 and the liquid crystal layer 3, the transparent electrode layer and the high resistance layer can be appropriately electrically insulated.

1.5. High resistance layer 5
The high resistance layer 5 may be a layer that can transmit light and has a sheet resistance of 1 kΩ to 10 GΩ. By interposing the high-resistance layer 5 between the second transparent electrode layer 2 and the liquid crystal layer 3, the liquid crystal molecules 3a existing inside the high-resistance layer 5 in a plan view are smoothly aligned when a voltage is applied. Can be made. The material which comprises the high resistance layer 5 is not specifically limited as long as said sheet resistance can be ensured, For example, a zinc oxide, PEDOT / PSS, or these combination can be used. The thickness condition of the high resistance layer 5 is not particularly limited as long as the above sheet resistance can be ensured. For example, when the liquid crystal lens 10 is applied to a spectacle lens, the thickness is 0.01 μm or more and 1 μm or less. It can be. The planar shape of the high resistance layer 5 is as follows. That is, as shown in FIG. 2, the high resistance layer 5 includes a circular first resistance layer 5a in plan view. 2, the outer edge of the high resistance layer 5 (the outer edge of the first resistance layer 5a) is the outermost of the plurality of annular electrode layers 2b ₁ , 2b ₂ ,. It is present inside the outer edge of the annular electrode layer 2b _5. By setting the planar shape of the high resistance layer 5 to such a shape, it is possible to suppress the generation of an electric field outside the annular electrode layer 2b ₅ in a plan view, and the orientation of the liquid crystal molecules 3a in the liquid crystal layer 3 on the outside. Can be suppressed. That is, the orientation change of the liquid crystal molecules 3a in the outer annular electrode layer 2b ₅ is, does not adversely affect the alignment of the liquid crystal molecules 3a in the inner annular electrode layer 2b _5. As a result, the liquid crystal molecules 3a in the liquid crystal layer 3 can be smoothly aligned in the intended direction inside the annular electrode layer 2b ₅ , effectively increasing the effective lens diameter and increasing the lens power. The lens 10 can be obtained.

In the liquid crystal lens 10, the outer edge of the high resistance layer 5 (the outer edge of the first resistance layer 5 a) is one annular electrode layer ₂ b of the plurality of annular electrode layers ₂ b ₁ , 2b ₂ ,. It is preferable that it exists within the band width of _x . In particular, as indicated by a dotted line in FIG. 2, the outer edge of the high-resistance layer 5 is inside the outer edge of the outermost annular electrode layer 2b _5, and, outside the inner edge of the outermost annular electrode layer 2b ₅ It is preferable to exist (that is, to exist within the band width of the outermost annular electrode layer 2b ₅ ). By making the planar shape of the high resistance layer 5 into such a shape, the above-described effects are more remarkably exhibited.

1.6. Other Configurations As described above, the liquid crystal lens 10 is characterized by the shape of the high-resistance layer 5 as compared with the conventional liquid crystal lens, and thereby exhibits remarkable and unique effects not found in the conventional liquid crystal lens. is there. The liquid crystal lens 10 can have the same configuration as the conventional liquid crystal lens except for the high resistance layer 5. For example, the first transparent electrode layer 1 and the second transparent electrode layer 2 can be formed on the surfaces of the transparent substrates 6 and 7, respectively. The first transparent electrode layer 1 and the second to the transparent electrode layer 2 are respectively electrically connected to a power source via a plurality of leads, as shown by V ₁ ~V ₆ in FIG. 1 The center electrode layer 2a and the annular electrode layers 2b, 2b,... Can be held at a predetermined potential with respect to the first transparent electrode layer 1. The lead wire drawing position is not particularly limited, and may be the same as the conventional one.

2. Liquid crystal lens 20
FIG. 5 schematically shows the layer structure of the liquid crystal lens 20. FIG. 6 schematically shows the planar shapes of the second transparent electrode layer 2 and the high resistance layer 15 provided in the liquid crystal lens 20.

  As shown in FIGS. 5 and 6, the liquid crystal lens 20 has a high resistance layer 15 that is separated from the first resistance layer 15 a and the first resistance layer 15 a around the first resistance layer 15 a in plan view. It is characterized in that it is provided with a ring-shaped second resistance layer 15b. Thus, by dividing the high resistance layer 15 into the first resistance layer 5a and the second resistance layer 5b, the orientation of the liquid crystal molecules 3a facing the first resistance layer 5a and the second resistance layer 5b It is considered that the orientation of the opposing liquid crystal molecules 3a can be individually controlled. Thereby, the orientation of the liquid crystal molecules 3a can be controlled to a more ideal form.

When the second resistance layer 15b is provided, the outer edge of the high resistance layer 15 (outer edge of the second resistance layer 15b) is the outermost of the plurality of annular electrode layers 2b ₁ , 2b ₂ ,. It is present inside the outer edge of the outer annular electrode layer 2b _5. Preferably, the outer edge of the high-resistance layer 5 is present in a plurality of annular electrode layer 2b _1, 2b 2, _... in the strip width of one annular electrode layer 2b _x of. In particular, as shown in FIG. 6, the outer edge of the high-resistance layer 15 is outside the inner edge of the outermost annular electrode layer 2b ₅ among the plurality of annular electrode layers 2b ₁ , 2b ₂ ,. It is preferable to exist (between the outer edge and the inner edge) (present within the band width of the outermost annular electrode layer 2b ₅ ).
Also, the inner edge of the second resistor layer 15b, it is preferably present in the band width of the annular electrode layer 2b _x other than the outermost annular electrode layer 2b5.
On the other hand, in a plan view, the outer edge of the first resistor layer 15a is preferably present in the outermost annular electrode layer 2b ₅ except in the band width of one annular electrode layer 2b _x.
In such a configuration, the electric field can be interrupted outside the first resistance layer 15a and inside the second resistance layer 15b in plan view. That is, the inner and outer optical phase difference distributions can be controlled with the boundary of the optical phase difference distribution of the liquid crystal layer 3 as a boundary, and the characteristics of the liquid crystal lens are maintained in a good state, and the liquid crystal lens is effectively effective. It is considered easier to enlarge the lens diameter and increase the effective lens power.

  Since the configuration of the liquid crystal lens 20 other than the high resistance layer 15 is the same as that of the liquid crystal lens 10, the description thereof is omitted here.

3. Liquid crystal lens 30
FIG. 7 schematically shows the layer structure of the liquid crystal lens 30. FIG. 8 schematically shows the planar shapes of the second transparent electrode layer 22 and the high resistance layer 25 provided in the liquid crystal lens 20.

  As shown in FIGS. 7 and 8, the liquid crystal lens 30 has a high resistance layer 25 that is separated from the first resistance layer 25 a and the first resistance layer 25 a around the first resistance layer 25 a in a plan view. And a second resistance layer 25b in the form of an annular zone. Thus, by dividing the high resistance layer 15 into the first resistance layer 25a and the second resistance layer 25b, the orientation of the liquid crystal molecules 3a facing the first resistance layer 25a and the second resistance layer 25b are opposed. It is considered that the orientation of the liquid crystal molecules 3a to be controlled can be individually controlled. Thereby, the orientation of the liquid crystal molecules 3a can be individually controlled to a more ideal form. Therefore, it is considered that it becomes easier to maintain the characteristics of the liquid crystal lens in a good state, effectively increase the effective lens diameter of the liquid crystal lens, and increase the effective lens power.

As shown in FIG. 8, in the liquid crystal lens 30, as in the liquid crystal lenses 10 and 20, the outer edge of the high resistance layer (outer edge of the second resistance layer 25b) is a plurality of annular electrode layers 22b _{1 in} plan view. , 22b ₂ ,... Are preferably located on the inner side of the outer edge of the outermost annular electrode layer 22b ₈ . The boundary of the optical phase difference distribution as shown in FIG. 9A is obtained by setting the voltage V ₇ applied to the annular electrode layer 22b ₇ to zero potential or low potential, adding the high voltage V ₉ , and adjusting the voltage V ₈ . Compared with the case where the portion is gentle, the boundary portion of the optical phase difference distribution of the liquid crystal layer 3 can be made steep as shown in FIG. It is considered that it becomes easier to effectively increase the effective lens diameter of the liquid crystal lens and to increase the effective lens power while maintaining a good state.

  The configuration of the liquid crystal lens 30 other than the second transparent electrode layer 22 and the high resistance layer 25 is the same as that of the liquid crystal lens 10, and thus the description thereof is omitted here.

4). Liquid crystal lens 40
FIG. 10 schematically shows the layer structure of the liquid crystal lens 40. In the liquid crystal lens 40, some of the annular electrode layers of the plurality of annular electrode layers constituting the second transparent electrode layer 2 are open without being electrically connected. That is, some of the plurality of annular electrode layers are open circuits. With such a configuration, the number of lead wires can be reduced, and the configuration of the liquid crystal lens can be simplified. In addition, due to the induced potential from the second transparent electrode layer 2 that is electrically connected, a gentle electric field is also generated directly below the second transparent electrode layer 2 that is not electrically connected, and the second transparent electrode layer 2 The liquid crystal molecules 3a immediately below the electrode layer 2 are also considered to be aligned in a predetermined direction. That is, a desired liquid crystal lens can be obtained without deteriorating optical characteristics even if the number of drive power supplies is reduced.

  Since the configuration of the liquid crystal lens 40 other than the connection method of the second transparent electrode layer 2 is the same as that of the liquid crystal lens 10, the description thereof is omitted here.

4). Other Forms In the liquid crystal lenses 10 to 40 of the present disclosure, each of the plurality of annular electrode layers may have a bandwidth that is characterized so that the impedance is approximately the same. In such a case, the potential of the annular electrode layer in the open circuit effectively becomes a value close to the average value of the potential of the adjacent annular electrode layer, so that the liquid crystal layer has a parabolic shape (cross section). It is considered possible to obtain a parabolic optical phase difference distribution more easily.

  In the above description, the second transparent electrode layer has been described as being composed of a circular center electrode layer and a concentric annular electrode layer. However, the second transparent electrode layer is not limited to this. It is not a thing. For example, as shown in FIG. 11, the second transparent electrode layer 102 is provided around the annular electrode layer 102b in a plan view, with a central electrode layer 102a and a plurality of annular electrode layers 102b, 102b,. And the outermost transparent electrode layer 102c. Even in such a case, it is considered that the effect of the liquid crystal lens of the present disclosure is exhibited without any problem.

  In the above description, the liquid crystal layer 3 is described as being filled with the liquid crystal molecules 3a between the predetermined alignment films 3b. However, the configuration of the liquid crystal layer 3 is not limited to this. As in the liquid crystal layer 13 shown in FIG. 12, the liquid crystal layer is formed by filling liquid crystal molecules 13a between one alignment film on the upper side of the paper and another alignment film on the lower side of the paper. Both the other alignment films may be constituted by the alignment film 13b and the vertical alignment film 13c. In other words, some liquid crystal molecules 13a in the liquid crystal layer 13 may be aligned in a different direction from the other liquid crystal molecules 13a by the vertical alignment film 13c. The vertical alignment film 13c is preferably provided in the vicinity of the outer edge of the high resistance layer in plan view. In such a configuration, the occurrence of disclination that adversely affects the optical characteristics of the liquid crystal lens due to discontinuous alignment of liquid crystal molecules, and as shown in FIG. The boundary portion of the optical phase difference distribution of the liquid crystal layer 13 can be made steep, and the liquid crystal lens characteristics are maintained in a good state as compared with the case where the boundary portion of the optical phase difference distribution is gentle, and the liquid crystal layer effectively It is considered possible to increase the effective lens diameter of the lens and increase the effective lens power. The alignment film shown in FIG. 12 can be configured by superposing the alignment film 23b and the vertical alignment film 23c and then removing a part of one film by etching or the like. As the normal alignment film 23b, a known one can be used as described above. As the vertical alignment film 23c, an alignment film made of a polyimide-based product in which the pretilt angle of the liquid crystal molecules stably shows 90 ° may be used.

  In the above description, the high resistance layers 5, 15, and 25 are described as including one or two resistance layers, but the form of the high resistance layer is not limited thereto. For example, in plan view, the high resistance layer includes a circular first resistance layer, a second resistance layer provided around the first resistance layer and spaced apart from the first resistance layer, A third resistance layer provided apart from the second resistance layer may be provided around the second resistance layer. The third resistance layer may be composed of a plurality of resistance layers. By dividing the high resistance layer into a first resistance layer, a second resistance layer, and a third resistance layer, the orientation of liquid crystal molecules facing the first resistance layer and the liquid crystal facing the second resistance layer It is considered that the orientation of the molecules and the orientation of the liquid crystal molecules facing the third resistance layer can be individually controlled. Thereby, the alignment of the liquid crystal molecules can be individually controlled to a more ideal form. Therefore, it is considered that it becomes easier to maintain the characteristics of the liquid crystal lens in a good state, effectively increase the effective lens diameter of the liquid crystal lens, and increase the effective lens power.

  Moreover, although the said description demonstrated the form in which only one liquid crystal layer 3 was provided, the structure of the liquid crystal layer 3 is not limited to this. For example, a plurality of liquid crystal layers may be provided in order to increase the lens power. The method for multilayering the liquid crystal layer is not particularly limited, and may be a known method.

  In the above description, the liquid crystal lenses 10 to 40 are individually described, but the liquid crystal lens of the present disclosure may be configured by combining a part of the configurations of the liquid crystal lenses 10 to 40 to form one liquid crystal lens. .

5. Method of Driving Liquid Crystal Lens The liquid crystal lens of the present disclosure can be driven as follows, for example. That is, the liquid crystal lens of the present disclosure can be driven by a liquid crystal lens driving method that controls the frequency of a voltage applied to one or more of the plurality of annular electrode layers. Thus, it is not necessary to change the resistance value of the high resistance layer, and the electric field distribution can be controlled by controlling the applied voltage and frequency, and the optical phase difference is parabolic (the cross section is parabolic). It is considered that it is possible to maintain the characteristics of the liquid crystal lens in a good state, effectively increase the effective lens diameter of the liquid crystal lens, and increase the effective lens power.

  Alternatively, the liquid crystal lens of the present disclosure can be driven by a liquid crystal lens driving method that controls the phase of an AC voltage applied to one or more of the plurality of annular electrode layers. For example, by changing the phase of the AC voltage to be applied by 180 °, the same effect as that of effectively applying a negative voltage can be obtained. Therefore, even in such a form, the electric field distribution can be controlled, and an optical phase difference distribution having a more ideal paraboloidal shape (cross-sectional parabolic shape) is obtained, and the characteristics of the liquid crystal lens are improved. Therefore, it is possible to effectively increase the effective lens diameter of the liquid crystal lens and to increase the effective lens power.

<Comparative Example 1>
As shown in FIG. 13, a liquid crystal lens not provided with a high resistance layer was produced, and the optical phase difference distribution characteristics were evaluated. First, a liquid crystal lens without a high resistance layer was produced by the following procedure.

A transparent transparent electrode layer made of ITO was formed on a 1 mm thick transparent glass substrate 6, and this was used as the first transparent electrode layer 1. On the other hand, a circular center electrode layer 2a made of ITO and five concentric annular electrode layers 2b, 2b,... Are formed on another transparent glass substrate 7 having a thickness of 1 mm. The transparent electrode layer 2 was obtained. The radius of the central electrode layer 2a is 1.6 mm, and the first annular electrode layer 2b ₁ (band width 5.4 mm) is formed with a distance of 0.2 mm from the central electrode layer 2a. A second annular electrode layer 2b ₂ (band width: 3.0 mm) is formed with a distance of 0.2 mm from the annular electrode layer 2b ₁ of the eye, and the second annular electrode layer 2b ₂ A third annular electrode layer 2b ₃ (band width 1.8 mm) is formed with a separation of 0.2 mm from the _third annular electrode layer 2b _{3 and is} separated by 0.2 mm with respect to the _third annular electrode layer 2b ₃ . A fifth annular electrode layer 2b ₄ (band width of 1.0 mm) is formed, and the fifth annular electrode layer 2b _{5 is} separated from the _fourth annular electrode layer 2b ₄ by 0.2 mm. (Band width 1.5 mm) was formed.

  An organic polymer film having a thickness of 5 μm was used as the insulating layer 4. However, in addition to the organic polymer film used in this example, the same effect can be obtained even when an amorphous quartz film having a thickness of 1 μm or less is used. In the configuration of FIG. 13, it is not necessary to provide an insulating layer in operation. However, in order to compare with the liquid crystal lens having the following high resistance layer, the characteristics when the same insulating layer is used are evaluated. It was.

  On both surfaces of the first transparent electrode layer 1 and the insulating layer 4, polyimide was applied as an alignment film to a thickness of 150 nm, stabilized by heat treatment, and then rubbed in one direction. RDP85475 (made by DIC) is filled as a liquid crystal material between the alignment film 3b on the surface of the first transparent electrode layer 1 and the alignment film 3b on the surface of the insulating layer 4, and the first transparent electrode layer 1 and the insulating layer 4 are filled. The liquid crystal layer 3 (thickness 60 μm) was provided between the two. In the liquid crystal layer 3, spacers were arranged to maintain the thickness.

  The respective layers were laminated so as to have a glass substrate / first transparent electrode layer / liquid crystal layer / insulating layer / second transparent electrode layer / glass substrate to obtain a liquid crystal lens according to Comparative Example 1.

With respect to the obtained liquid crystal lens, a voltage was applied to and held on the electrode under the following conditions, and the optical phase difference distribution was evaluated. The results are shown in FIG.
(conditions)
f = 1kHz
V ₁ = 3.0V
V ₂ = 3.2V
V ₃ = 3.6V
V ₄ = 4.0V
V ₅ = 4.8V
V ₆ = 6.3V

  As shown in FIG. 14, the liquid crystal lens according to Comparative Example 1 exhibited characteristics as a lens by including a plurality of annular electrodes. However, the optical phase difference characteristic is not smooth and discontinuous, and the performance is insufficient for application as a lens.

<Comparative example 2>
As shown in FIG. 15, a liquid crystal lens having a double layer of an insulating layer and a high resistance layer was produced. That is, in the liquid crystal lens according to Comparative Example 1, the first transparent electrode layer 1 and the first transparent electrode layer 1 are the same as Comparative Example 1 except that a double layer of an insulating layer and a high resistance layer is provided instead of the insulating layer. 2 transparent electrode layer 2 and liquid crystal layer 3 were produced, and a liquid crystal lens according to Comparative Example 2 was obtained. The obtained liquid crystal lens was evaluated for optical phase difference distribution characteristics.

  The double layer was produced as follows. That is, a zinc oxide thin film (thickness 25 nm) was formed as the high resistance layer 5 on the surface of the insulating layer 4 by a high frequency sputtering method to obtain a double layer. An alignment film 3b was provided on the surface of the double layer on the high resistance layer 5 side under the same conditions as in Comparative Example 1, and the liquid crystal layer 3 was sandwiched under the same conditions as in Comparative Example 1.

With respect to the obtained liquid crystal lens, a voltage was applied to and held on the electrode under the following conditions, and the optical phase difference distribution was evaluated. The results are shown in FIG.
(conditions)
f = 1kHz
V ₁ = 0.21V
V ₂ = 1.7V
V ₃ = 2.6V
V ₄ = 2.8V
V ₅ = 4.0V
V ₆ = 5.3V

  As shown in FIG. 16, the liquid crystal lens according to Comparative Example 2 had a smooth and continuous optical phase difference characteristic. However, the liquid crystal molecules cannot be oriented in the intended direction in the vicinity of the outer edge of the second transparent electrode layer 2 in plan view, and as a result, the effective lens diameter of the liquid crystal lens is reduced. This is considered to be caused by the following. That is, in the liquid crystal lens according to Comparative Example 2, the double layer of the insulating layer 4 and the high resistance layer 5 is configured to cover the entire surface of the liquid crystal layer 3, and the area of the high resistance layer 5 is the first in a plan view. It is considered to be larger than the area of the two transparent electrode layers 2. When a high resistance layer having such a large area is provided, when a voltage is applied between the first and second transparent electrodes, the high resistance layer 5 is also formed on the outer side of the second transparent electrode layer 2 in a plan view. An electric field is generated by induction, and as a result, the inclination of the liquid crystal molecules 3a in the liquid crystal layer 3 changes. In such a case, the orientation of the liquid crystal molecules 3a outside the second transparent electrode layer 2 adversely affects the orientation of the liquid crystal molecules 3a inside the second transparent electrode layer 2, and the second transparent electrode layer 2 It is considered that the liquid crystal molecules could not be aligned in the intended direction in the vicinity of the outer edge of the film.

<Example 1>
As shown in FIGS. 1 and 2, in the liquid crystal lens having a double layer of the insulating layer 4 and the high resistance layer 5, the shape of the high resistance layer 5 was processed into a circular shape. Further, in the second electrode layer 2 ′, the outermost electrode layer 2 b ₅ was formed in a ring shape (band width of 0.8 mm) to form the second electrode layer 2. Thus, the first transparent electrode layer 1, the second transparent electrode layer 2, the liquid crystal layer 3, and the second liquid crystal layer 2 are the same as in Comparative Example 2 except that the shapes of the second electrode layer and the high resistance layer are changed. Multilayers were prepared to obtain a liquid crystal lens according to Example 1. The obtained liquid crystal lens was evaluated for optical phase difference distribution characteristics.

Incidentally, in plan view, the outer edge of the high-resistance layer 5 was made to be inside the outer edge of the outermost annular electrode layer 2b _5. More specifically, the outer edge of the high resistance layer 5 is located inside the outer edge of the outermost ring electrode layer 2b5 and outside the inner edge.

With respect to the obtained liquid crystal lens, a voltage was applied to and held on the electrode under the following conditions, and the optical phase difference distribution was evaluated. The results are shown in FIG.
(conditions)
f = 3 kHz
V ₁ = 0.25V
V ₂ = 1.4V
V ₃ = 1.8V
V ₄ = 1.9V
V ₅ = 1.8V
V ₆ = 5.4V

  As shown in FIG. 17, in the liquid crystal lens according to Example 1, it was shown that the liquid crystal lens according to Comparative Example 2 approaches the liquid crystal molecular alignment exhibiting better lens characteristics. It can be considered that an electric field is prevented from being generated outside the annular electrode layer 2b in a plan view, and a change in orientation of the liquid crystal molecules 3a in the liquid crystal layer 3 can be suppressed. That is, the change in the orientation of the liquid crystal molecules 3a outside the annular electrode layer 2b does not adversely affect the orientation of the liquid crystal molecules 3a inside the annular electrode layer 2b. , The liquid crystal molecules 3a in the liquid crystal layer 3 can be aligned in the intended direction, resulting in an optical phase difference distribution with a paraboloidal shape (the cross section is parabolic), and the liquid crystal lens characteristics are maintained in a good state and effective. In particular, the effective lens diameter of the liquid crystal lens could be expanded.

  The liquid crystal lens of the present disclosure can be used for all kinds of lenses from small lenses to medium / large lenses. In particular, it can be suitably used as a lens for both near and near spectacles.

DESCRIPTION OF SYMBOLS 1 1st transparent electrode layer 2, 22 2nd transparent electrode layer 3 Liquid crystal layer 4 Insulating layer 5, 15, 25 High resistance layer 6 Substrate 7 Substrate 10, 20, 30, 40 Liquid crystal lens

Claims (10)

A first transparent electrode layer; a second transparent electrode layer; a liquid crystal layer provided between the first transparent electrode layer and the second transparent electrode layer; the second transparent electrode layer; An insulating layer provided between the liquid crystal layers, and a high resistance layer provided between the insulating layer and the liquid crystal layer,
In a plan view, the second transparent electrode layer includes a circular center electrode layer and a plurality of annular electrode layers provided around the center electrode layer and spaced apart from the center electrode layer. And
In plan view, the liquid crystal layer is present both inside and outside the outer edge of the outermost ring electrode layer of the plurality of ring electrode layers,
In a plan view, the high resistance layer includes a circular first resistance layer,
In plan view, the outer edge of the high resistance layer is present within the band width of the outermost ring electrode layer of the plurality of ring electrode layers,
Liquid crystal lens. In the plan view, an outer edge of the first resistance layer exists within a band width of any one of the plurality of annular electrode layers.
The liquid crystal lens according to claim 1. In the plan view, the high resistance layer includes the first resistance layer and an annular second resistance layer provided around the first resistance layer and spaced apart from the first resistance layer. El Bei the door,
The liquid crystal lens according to claim 1 or 2. In the plan view, an outer edge of the second resistance layer is present within any one of the plurality of annular electrode layers.
The liquid crystal lens according to claim 3. In a plan view, the high resistance layer includes a third resistance layer provided around the second resistance layer and spaced apart from the second resistance layer.
The liquid crystal lens according to claim 3 or 4. A part of the plurality of annular electrode layers is an open circuit,
The liquid crystal lens according to claim 1. Each of the plurality of annular electrode layers has a bandwidth characterized to have similar impedance;
The liquid crystal lens according to claim 1. The second transparent electrode layer includes the center electrode layer, the plurality of annular electrode layers, and an outermost transparent electrode layer provided around the annular electrode layer in the plan view.
The liquid crystal lens according to claim 1. A method for driving the liquid crystal lens according to claim 1,
Controlling the frequency of the voltage applied to one or more of the plurality of annular electrode layers,
Liquid crystal lens driving method. A method for driving the liquid crystal lens according to claim 1,
Controlling the phase of the alternating voltage applied to one or more of the plurality of annular electrode layers,
Liquid crystal lens driving method.