JP2010266551A - Liquid crystal lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal lens having high transparency. <P>SOLUTION: The liquid crystal lens includes a liquid crystal (2) which is seal-packed in a cavity formed by laminating a fresnel lens (3) and a transparent base material (4) together, wherein a focal length is varied by changing the abnormal refractive index of the liquid crystal (2). An annular wall (13) is formed surrounding the outer periphery of the fresnel lens (3), and a recess (14) for receiving a liquid crystal sealing agent (11) is formed at the edge of the annular wall (13) abutting on the transparent base material (4). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid crystal lens using a Fresnel lens, and more particularly to a technique for sealing a liquid crystal of a liquid crystal lens.

  Conventionally, in a liquid crystal lens, a pair of transparent substrates made of glass or plastic are arranged to face each other, and transparent conductive films for driving liquid crystals are laminated on the surfaces facing each other. On the surface of these transparent conductive films, a polymer alignment film subjected to an alignment treatment is formed in order to align liquid crystal molecules in a certain (arbitrary) form. Liquid crystal is filled in the pair of transparent substrates subjected to the alignment treatment, and sealed with a liquid crystal sealant.

The liquid crystal can change the extraordinary refractive index according to the applied potential difference, and the liquid crystal lens has a variable focal length by utilizing the extraordinary refractive index.
The liquid crystal sealant plays an important role of protecting the liquid crystal filled between the transparent substrates by bonding them together from the outside, and UV curing, heat curing, or a hybrid resin (no affinity with liquid crystals). ) Has already been disclosed.

JP 2002-182181 A JP 2007-248983 A

  However, many fillers (additives) for increasing the viscosity and moisture resistance are used in the liquid crystal sealant, and the liquid crystal sealant penetrates into the sealed liquid crystal, thereby transmitting the liquid crystal lens. The light to be scattered is scattered (white turbidity) by the filler inside the liquid crystal sealant, and the transparency is lowered.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a liquid crystal lens having high transparency.

  The liquid crystal lens according to claim 1 of the present invention seals the liquid crystal in a space formed by bonding the Fresnel lens and the transparent base material, and changes the extraordinary refractive index of the liquid crystal to vary the focal length. An annular wall surrounding an outer peripheral portion is formed on one of the Fresnel lens or the transparent substrate, and a liquid crystal is provided on an end surface of the annular wall that contacts the other of the Fresnel lens or the transparent substrate. A recess for accommodating the sealant is formed.

  The liquid crystal lens according to claim 2 of the present invention seals the liquid crystal in a space formed by bonding the Fresnel lens and the transparent base material, and changes the extraordinary refractive index of the liquid crystal to vary the focal length. In the liquid crystal lens, the Fresnel lens is formed with an annular wall that surrounds an outer peripheral portion, and a recess for accommodating a liquid crystal sealant is formed on an end surface of the annular wall that contacts the transparent substrate. It is characterized by.

  According to a third aspect of the present invention, in the liquid crystal lens, the liquid crystal is sealed in a space formed by bonding the Fresnel lens and the transparent substrate, and the focal length is varied by changing the extraordinary refractive index of the liquid crystal. In the liquid crystal lens, an annular wall surrounding an outer peripheral portion is formed on the transparent base material, and a recess for accommodating a liquid crystal sealant is formed on an end surface of the annular wall that contacts the Fresnel lens. Features.

  A liquid crystal lens according to a fourth aspect of the present invention is the liquid crystal lens according to the second or third aspect, wherein the height of the annular wall from the bottom of the concave portion is such that the inner peripheral side close to the space in which the liquid crystal is sealed is the outer peripheral side. It is characterized by being higher than.

The liquid crystal lens according to claim 5 of the present invention is characterized in that, in claim 2 or claim 3, the end face of the annular wall is subjected to a liquid repellent treatment.
According to a sixth aspect of the present invention, in the liquid crystal lens according to the second or third aspect, the opening of the concave portion is wider than the bottom surface thereof.

A liquid crystal lens according to a seventh aspect of the present invention is the liquid crystal lens according to the second or third aspect, wherein the liquid crystal sealant has a surface tension: T, a contact angle: θ, a liquid density: ρ, a gravitational acceleration: g, When the inner diameter (radius) is r, the width of the recess is d, and the height of the recess is h, the liquid crystal sealant is filled into the recess using a capillary phenomenon.
h = (2 · T · cos θ) / (ρ · g · r)
h = (4 · T · cos θ) / (ρ · g · d)
It is characterized by being set to.

  According to this configuration, the annular wall surrounding the outer peripheral portion is formed on one of the Fresnel lens or the transparent substrate, and the end surface of the annular wall contacting the other of the Fresnel lens or the transparent substrate is sealed with liquid crystal Since the concave portion for containing the agent is formed, the step of the concave portion and the capillary phenomenon are prevented so that the liquid crystal sealing agent is not mixed into the liquid crystal sealed in the space formed by bonding the Fresnel lens and the transparent base material. Therefore, it is possible to make a liquid crystal lens having a high transmittance without causing the lens effective portion to become clouded by the liquid crystal sealant.

1 is a plan view of a liquid crystal lens, a cross-sectional view of the liquid crystal lens, and an enlarged cross-sectional view of the vicinity of the outer periphery of the liquid crystal lens in Embodiment 1 of the present invention The expanded sectional view of the Fresnel lens 3 of the embodiment Schematic of processing process of a molding die for molding the Fresnel lens 3 of the same embodiment Process drawing of molding process of Fresnel lens 3 of the embodiment Configuration diagram of a transparent conductive film or insulating film lamination forming apparatus of the same embodiment Process diagram from application of alignment film to alignment process of the same embodiment Explanatory drawing of the filling process of the liquid crystal sealing agent 11 in the annular wall 13 of the embodiment and an enlarged cross-sectional view of the Fresnel lens 3 filled with the liquid crystal sealing agent 11 Explanatory drawing of the lens bonding process of the same embodiment The expanded sectional view which shows the liquid repellent part 44a, 44b formed in the upper surface 15 of the inner peripheral side of the annular wall 13 of the same embodiment, and the upper surface 16 of an outer peripheral side Explanatory drawing of the formation process of the liquid repellent parts 44a and 44b of the embodiment A plan view and a sectional view of a masking plate 45 used in the formation process of the liquid repellent portions 44a and 44b of the embodiment. The top view and sectional drawing which show another specific example of the recessed part 14 of the embodiment, and the top view of another specific example The expanded sectional view which gave the inclination or the curvature to the opening of the recessed part of the embodiment Plan view of liquid crystal lens according to Embodiment 2 of the present invention, cross-sectional view of liquid crystal lens, and enlarged cross-sectional view near the outer periphery of liquid crystal lens

Embodiments of the liquid crystal lens of the present invention will be described with reference to FIGS.
(Embodiment 1)
FIG. 1A, FIG. 1B, and FIG. 1C show a plan view and a cross-sectional view of the liquid crystal lens according to Embodiment 1 of the present invention, and an enlarged cross-section of the connecting portion.

  The liquid crystal lens 1 is configured by filling a liquid crystal 2 between a Fresnel lens 3 and a transparent substrate 4. In the Fresnel lens 3, an annular wall 13 is formed on the outer peripheral portion, and an unevenness 100 in which only the curvature of the lens is arranged on a plane is formed on the inner peripheral portion of the annular wall 13. The flat transparent substrate 4 is bonded to the end face of the annular wall 13 of the Fresnel lens 3, and the liquid crystal 2 is filled between the unevenness 100 of the Fresnel lens 3. 11 is a liquid crystal sealing agent. Further, the Fresnel lens 3 and the transparent base material 4 are joined by a transparent adhesive 12.

  More specifically, the annular wall 13 is formed so as to surround the outer periphery of the Fresnel lens 3 in order to seal the liquid crystal 2 between the opposing surfaces (spaces) of the Fresnel lens 3 and the transparent substrate 4. For the purpose of preventing the liquid crystal 2 from flowing out and narrowing the area where the liquid crystal sealant 11 is used, the end surface of the annular wall 13 has a lens surface 18 of the Fresnel lens 3 and a rise surface of the Fresnel lens 3 as shown in FIG. 19 is formed higher than the lens top portion 17 of the Fresnel lens formed by 19.

  A recess 14 is formed on the end surface of the annular wall 13, and the height H 1 of the inner peripheral upper surface 15 is higher than the height H 2 of the outer peripheral upper surface 16 across the recess 14. The height used here is the distance of the bottom surface of the recess 14. Specifically, the dimension of (H1−H2) is 3 μm to 5 μm, and the dimension of d is 5 μm to 10 μm.

  This is a spacer structure formed to prevent the liquid crystal sealant 11 from entering the lens effective area 20 of the Fresnel lens 3 and to control the ground contact distance between the Fresnel lens 3 and the transparent substrate 4.

Here, a plurality of recesses 14 are provided at predetermined intervals along the circumferential direction of the annular wall 13, and these recesses 14 are arranged so as to surround the Fresnel lens 3.
A first transparent conductive film 5 is formed on the surface of the unevenness 100 in contact with the liquid crystal 2 of the Fresnel lens 3. A first insulating film 6 is formed on the surface of the first transparent conductive film 5, and a first alignment film 7 is formed on the surface of the first insulating film 6.

  A second transparent conductive film 8 is also formed on the surface of the transparent substrate 4 in contact with the liquid crystal 2, and a second insulating film 9 is formed on the surface. A second alignment film 10 having the same function as the first alignment film 7 is formed on the surface of the second insulating film 9.

The first and second transparent conductive films 5 and 8 are, for example, ITO (In ₂ O ₃ —SnO ₂ ) films that are particularly highly conductive among the existing transparent conductive films and are excellent in transparency and patternability. . The material of the first and second transparent conductive films 5 and 8 is not particularly limited to this, and a transparent conductive oxide TCO (Transparent Conductive Oxide) represented by SnO ₂ and ZnO is also preferably used. Is possible.

In addition, the first and second insulating films 6 and 9 are SiO ₂ films, and the first and second alignment films 7 and 10 can be formed at a low temperature and can be patterned from the viewpoint of limiting the heat-resistant temperature of the plastic material. Is an excellent polyvinyl alcohol film.

For the production of the Fresnel lens 3, a mold produced as shown in FIGS. 3A and 3B is used.
As shown in FIG. 3A, a metal base plate 21 that is a mold material is fixed on the rotating plate 23.

  In FIG. 3B, the first Fresnel lens molding metal having an arbitrary shape is formed by rotating while pressing the diamond bit 22 against the surface of the metal base plate 21 and gradually increasing the depth of cut. A mold 25 can be manufactured.

Here, as a material of the metal base plate 21, a general mold material such as a copper alloy, an aluminum alloy, or pre-hardened steel can be suitably used.
In addition, when a fine pattern obtained by processing with a higher required dimensional accuracy of the molding die is required, a technique such as nanoimprint using a resist or the like is employed.

  Using this first Fresnel lens molding die 25, the Fresnel lens 3 is molded by the molding process of FIGS. 4 (a), 4 (b), and 4 (c). Note that the second Fresnel lens molding die 26 has a flat surface facing the first Fresnel lens molding die 25 and is manufactured to cover the first Fresnel lens molding die 25. .

In FIG. 4A, a transparent plastic material 27 heated to a Tg point (glass transition point) or higher is applied to the surface of the first Fresnel lens molding die 25.
Next, in FIG. 4 (b), the first Fresnel lens molding die 25 is pressed against the surface of the second Fresnel lens molding die 26 while performing vacuum degassing, and after cooling and hardening, in FIG. 4 (c). The Fresnel lens 3 is molded by releasing the mold.

A first transparent conductive film 5 and a first insulating film 6 are formed on the released Fresnel lens 3 using the sputtering apparatus shown in FIG. In FIG. 5, the sputtering method is used to form the first transparent conductive film 5. This is because when the ITO film and the SiO ₂ film are laminated on the plastic material as the lens material, the mutual adhesion is good, and thus the sputtering method is excellent.

Here, the vacuum chamber 28 is evacuated in advance to a pressure of about 1 × 10 ⁻⁴ Pa to 4 × 10 ⁻⁴ Pa, and the Fresnel lens 3 of the transparent plastic substrate is disposed on the substrate holder facing the sputtering target 29. 30 is fixed.

At the start of film formation, Ar (argon), which is an inert gas, and O ₂ (oxygen), which is an active gas, are introduced as a process gas 33 from a gas introduction path 32, and the pressure is about 0.1 to 0.5 Pa. In this way, film stacking (sputtering) is performed.

  After introducing the process gas 33, a bias is applied between the substrate holder 30 and the sputtering target 29 to cause dielectric breakdown (glow discharge) 34 of the process gas 33, and sputter ions 35 are blown off. The sputter ions 35 rush into the surface of the sputtering target 29 one after another with energy, and as a result, the radical ions 36 and secondary electrons 37 necessary for forming the film stack are repelled from the surface of the sputtering target 29. Fly.

  Thereafter, the radical ions 36 form a film (volume) on the Fresnel lens 3, while the secondary electrons 37 repeatedly collide with the process gas 33 to maintain the dielectric breakdown (glow discharge) 34. Film formation is possible.

  Here, when an optical plastic material typified by polycarbonate or acrylic is used as in the present invention, a film forming process at 150 ° C. or less, preferably at room temperature, is required due to the limitation of the heat resistance temperature. Since the ITO film to be laminated has a crystallization start temperature of about 160 ° C. to 180 ° C., it should be noted that it is amorphous.

Note that the second transparent conductive film 8 and the second insulating film 9 are also formed on the transparent substrate 4 by the sputtering apparatus of FIG.
In contrast to the Fresnel lens 3 having the first transparent conductive film 5 and the first insulating film 6 formed on the surface, the first insulation is shown in FIGS. 6 (a), 6 (b), and 6 (c). A first alignment film 7 is formed on the surface of the film 6.

  In FIG. 6A, on the sputtered transparent plastic substrate 39 (the Fresnel lens 3 having the first transparent conductive film 5 and the first insulating film 6 formed on the surface), a quantitative dropping method such as a dispenser is used. 0.1% polyvinyl alcohol aqueous solution 38 is dropped.

  The dropped 0.1% polyvinyl alcohol aqueous solution 38 is uniformly applied at about 3000 revolutions per minute using a spin coater 40 (spin coating method) in FIG. It is formed by sufficiently drying. After baking and drying in the oven, the 0.1% polyvinyl alcohol aqueous solution 38 in FIG. 6 (c) is obtained by rubbing a roller 42 with a velvet cloth 42 (weaving feathers on the fabric surface) in a certain direction. (Orientation treatment).

  In general, the alignment of liquid crystals is known to be controlled by organic residues exposed on the outermost surface of the alignment film. On the polyvinyl alcohol film, molecules are aligned horizontally with respect to the main chain rearranged in the rubbing direction. Thus, the first alignment film 7 is completed.

Similarly, the second alignment film 10 is formed on the transparent substrate 4 side.
Next, with respect to the Fresnel lens 3 on which the first transparent conductive film 5, the first insulating film 6 and the first alignment film 7 are formed, the concave portions 14 of the annular wall 13 are formed in the concave portions 14 in FIG. The liquid crystal sealant 11 is filled as shown in FIG.

  The liquid crystal sealant 11 is obtained by dissolving an oligomer having a relatively low molecular weight in a reactive diluent, and is an ultraviolet / thermosetting resin having an epoxy group or a (meth) acryloyl group as a reactive group. The liquid crystal sealant 11 is supplied by applying about 2.5 to 3 pl to the center of each recess 14 while moving the ink jet nozzle 43 in the arrangement direction of the recess 14 in the annular wall 13 (arrow FF direction). The width of the annular wall 13 represented by the total width of the upper surface 15 on the inner peripheral side, the concave portion 14 and the upper surface 16 on the outer peripheral side is about 50 to 70 μm, and the application range at one time is about 20 to 25 μm.

Here, the width d of the recess 14 and the height h of the recess 14 are set so that the liquid crystal sealant 11 is filled in the recess 14 using capillary action.
h = (2 · T · cos θ) / (ρ · g · r)
h = (4 · T · cos θ) / (ρ · g · d)
T: Surface tension [N / m]
θ: Contact angle
ρ: Density of liquid [kg / m ³ ]
g: Gravity acceleration = 9.80665 [m / s ² ]
r: Inner diameter (radius) of the recess 14 [m]
It is prescribed to satisfy.

  In contrast to the Fresnel lens 3 in which the concave portions 14 of the annular wall 13 are filled with the liquid crystal sealing agent 11, in FIG. 8, the space between the Fresnel lens 3 and the transparent base material 4 is filled with the liquid crystal 2. 4 are pasted together.

  In FIG. 8A, the liquid crystal 2 is applied dropwise onto the surface of the first alignment film 6 (within the lens effective area of the Fresnel lens) using the dispenser method or the ink jet method simultaneously with the application of the liquid crystal sealant 11. Is done. Here, it is necessary to select a liquid crystal sealant 11 that has no or little compatibility with the liquid crystal 2 to be used.

In FIG. 8 (b), the Fresnel lens 3 and the transparent substrate 4 are bonded together under a vacuum of about 1 × 10 ⁻⁴ Pa to 4 × 10 ⁻⁴ Pa, and temporarily cured by ultraviolet irradiation or blue visible light irradiation. The As the irradiation light source, a known light source such as a high-pressure mercury lamp, a metal halide lamp, or a light emitting diode can be used. At the time of pasting, the adhesive 12 is also simultaneously applied by a dispenser method or an inkjet method, and heating by an oven (about 80 to 90 ° C./several tens of minutes) is performed as the main curing.

When filling the liquid crystal sealant 11 shown in FIG. 7A, the liquid repellent portions 44a and 44b are formed on the inner peripheral side upper surface 15 and the outer peripheral side upper surface 16 of the annular wall 13 as shown in FIG. Is formed.
As the liquid repellent portions 44a and 44b, those having a surface energy larger than that of the liquid crystal sealant 11 and those having an outermost layer of an oxide or fluoride are preferably used. For example, a thin SiO ₂ film of 5 nm or less is formed, and a water repellent layer (a material containing a perfluoroalkyl group) is further laminated.

FIG. 10 shows a method of forming the liquid repellent portions 44a and 44b.
In FIG. 10, the liquid repellent portions 44a and 44b can be formed by patterning a fluoride deposit on the liquid crystal alignment film using a vacuum deposition method. The fluoride evaporation source 45 is heated by a heater 47 at the bottom of the vacuum chamber 46 to generate a fluoride evaporation 48. The gaseous fluoride vapor 48 is sublimated, and liquid repellent portions 44 a and 44 b are formed on the upper surface of the annular wall 13 that is not masked by the masking plate 49. 11A and 11B are plan views of the masking plate 49 used in the process of forming the liquid repellent portions 44a and 44b in FIG. 10, and the openings 49b and 49b of the masking plate 49 and the Fresnel lens 3. 3 is a cross-sectional view showing a positional relationship with an annular wall 13. FIG.

Thus, by forming the liquid repellent portions 44 a and 44 b around the concave portion 14 at the end face of the annular wall 13, the following effects can be obtained.
As the liquid crystal sealant 11, there is also a material having high affinity for a plastic substrate (organic synthetic resin). When such a liquid crystal sealant 11 is used, when the liquid crystal sealant 11 is supplied to the upper surface of the annular wall 13, the bonding surface is obtained by bonding the transparent substrate 4 to the Fresnel lens 3. The upper liquid crystal sealant 11 exceeds the effect of the osmotic pressure of the recess 14 and the step difference between the inner peripheral side and the outer peripheral side of the annular wall 13, and a part of the liquid crystal sealant 11 is a lens inside the annular wall 13. There is a risk of moving to the effective area 20. The liquid repellent portions 44a and 44b are formed around the concave portion 14, and the liquid crystal sealant 11 is supplied to the concave portion 14 by making the supply position of the liquid crystal sealant 11 by the inkjet nozzle 43 or the like outside the liquid repellent portion 44a. The effect of attracting can be obtained, and a situation in which a part of the liquid crystal sealant 11 moves to the lens effective region 20 can be avoided, and it is further effective for producing a liquid crystal lens having a high transmittance.

  In addition, although the recessed part 14 was arrange | positioned in the end surface of the annular wall 13 of the Fresnel lens 3 so that the lens effective area | region 20 of the Fresnel lens 3 might be enclosed, the cross section of Fig.12 (a) and FIG.12 (a) is shown. As shown in FIG. 12B, it is also possible to provide a C-shaped recess 14 that does not form the recess 14 at only one location on the end face of the annular wall 13. Further, as shown in FIG. 12C, an annular recess 14 having a shape similar to the outer peripheral shape of the Fresnel lens 3 that completely surrounds the lens effective region 20 can be provided on the end surface of the annular wall 13. .

  In the case of the recess 14 having the shape shown in FIG. 12C, the overflow of the liquid crystal sealant 11 can be minimized, but on the other hand, the transparent electrode is patterned in the very narrow recess 14 to form a first electrode. Since one transparent conductive film 5 must be connected to an external drive circuit, the electrode is difficult to take out. On the other hand, in the case of the shape of FIG. 7A or FIG. 12A, it is easy to draw the electrode to the outside from the portion where the recess 14 is not formed.

  In the above embodiment, the concave portion 14 has a groove shape in which the width of the bottom and the opening is the same as shown in the enlarged view of FIG. 2, but this is because the opening is formed wider than the bottom. The liquid crystal sealant 11 can be reliably pulled by the recess 14. As a specific shape, when the opening of the recess 14 is formed on an inclined surface having a curvature as shown in FIG. 13 (a), or the opening of the recess 14 is a straight line as shown in FIG. 13 (b). In some cases.

  In the first embodiment, the transparent base material 4 is a parallel plate. However, the transparent base material 4 can be any one of a spherical lens, an aspherical lens, and a Fresnel lens that refracts on the surface of the base material. Moreover, the transparent base material 4 can also be made into either the refractive index distribution lens which does not refract on the base-material surface, or a diffraction lens.

(Embodiment 2)
14 (a) to 14 (c) show a liquid crystal lens according to Embodiment 2 of the present invention.
As shown in FIGS. 1A to 1C, the liquid crystal lens 1 of Embodiment 1 has an annular wall 13 that surrounds the outer periphery of the Fresnel lens 3. The concave portion 14 that accommodates the liquid crystal sealant 11 is formed on the end face of the annular wall 13 that is in contact, but in the liquid crystal lens 1A of the second embodiment, the space formed by bonding the Fresnel lens 3 and the transparent substrate 4 together. The liquid crystal 2 is sealed, and the liquid crystal lens is the same in that the focal length is changed by changing the extraordinary refractive index of the liquid crystal 2, but the annular wall 13 surrounding the outer peripheral portion is formed on the transparent substrate 4. The only difference is that a concave portion 14 for accommodating the liquid crystal sealant 11 is formed on the end face of the annular wall 13 in contact with the Fresnel lens 3. Other embodiments described in the first embodiment can also be implemented in the second embodiment, and similar effects can be expected.

  The present invention contributes to improving the performance of various optical devices such as electronic glasses, optical microscopes, digital cameras, and digital video cameras that use liquid crystal lenses.

1, 1A liquid crystal lens 2 liquid crystal 3 Fresnel lens 4 transparent substrate 5 first transparent conductive film 6 first insulating film 7 first alignment film 8 second transparent conductive film 9 second insulating film 10 second Alignment film 11 Liquid crystal sealant 12 Adhesive 13 Annular wall 14 Recess 15 Upper surface 16 on the inner peripheral side of the annular wall 13 Upper surface 17 on the outer peripheral side of the annular wall 13 Lens top 18 of the Fresnel lens Fresnel lens lens surface 19 Fresnel lens Rise surface 20 Annular wall 43 of Fresnel lens Inkjet nozzles 44a, 44b Liquid repellent part

Claims (7)

A liquid crystal lens that seals liquid crystal in a space formed by bonding a Fresnel lens and a transparent base material, and changes the extraordinary refractive index of the liquid crystal to change the focal length,
One of the Fresnel lens or the transparent substrate is formed with an annular wall surrounding the outer periphery,
The liquid crystal lens in which the recessed part which accommodates a liquid-crystal sealing agent is formed in the end surface of the said annular wall which contact | abuts the other of the said Fresnel lens or the said transparent base material. A liquid crystal lens that seals liquid crystal in a space formed by bonding a Fresnel lens and a transparent base material, and changes the extraordinary refractive index of the liquid crystal to change the focal length,
The Fresnel lens is formed with an annular wall surrounding the outer periphery,
A liquid crystal lens in which a concave portion for accommodating a liquid crystal sealant is formed on an end surface of the annular wall in contact with the transparent substrate. A liquid crystal lens that seals liquid crystal in a space formed by bonding a Fresnel lens and a transparent base material, and changes the extraordinary refractive index of the liquid crystal to change the focal length,
An annular wall surrounding the outer periphery is formed on the transparent substrate,
A liquid crystal lens in which a concave portion for accommodating a liquid crystal sealant is formed on an end surface of the annular wall that contacts the Fresnel lens. 4. The liquid crystal lens according to claim 2, wherein a height of the annular wall from a bottom portion of the concave portion is higher on an inner peripheral side near the space in which liquid crystal is sealed than on an outer peripheral side. The liquid crystal lens according to claim 2, wherein the end surface of the annular wall is subjected to a liquid repellent treatment. The liquid crystal lens according to claim 2, wherein the recess has a wider opening than a bottom surface thereof. Surface tension: T, contact angle: θ, liquid density: ρ, gravitational acceleration: g, inner diameter (radius) of the recess: r, width of the recess: d, height of the recess: h If so, so that the liquid crystal sealant is filled into the recess using the capillary phenomenon,
h = (2 · T · cos θ) / (ρ · g · r)
h = (4 · T · cos θ) / (ρ · g · d)
The liquid crystal lens according to claim 2 or 3, wherein the liquid crystal lens is set as follows.

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