JP2009192791A - Liquid crystal lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal lens that can have high precision of diffraction limit and obtain full optical performance, includes a low-cost constitution, and is superior in mass-productivity, wherein one of a finite system and an infinite system securely includes an RMS value of a spherical aberration below λ/14 (Marechal condition), even in a wide wavelength band of visible light although the liquid crystal lens can be dynamically switched as a varifocal lens between the finite system and infinite system. <P>SOLUTION: The liquid crystal lens 1 includes a lens surface 4 formed on at least one of surfaces of two transparent substrates 2a and 2b having liquid crystal 3 sandwiched therebetween, the surfaces being in contact with the liquid crystal 3. The Abbe number of members constituting the transparent substrates 2a and 2b including the lens surface 4 is equal to the Abbe number of an ordinary light refractive index of the liquid crystal 3 or the Abbe number of an extraordinary light refractive index. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal lens that maintains good optical performance with small chromatic aberration and can be realized with a simple configuration regardless of a wide wavelength band of visible light.

  2. Description of the Related Art Conventionally, liquid crystal lenses have been proposed that can freely switch light focusing and divergence in accordance with each application in imaging optical systems such as glasses and cameras and in projection optical systems such as projectors. (For example, refer to Patent Document 1).

  Hereinafter, a configuration of a conventional liquid crystal lens will be described with reference to the drawings. FIG. 5 shows a cross-sectional view of the liquid crystal lens described in Patent Document 1. As shown in FIG.

  A liquid crystal lens 101 shown in FIG. 5 includes two transparent substrates 102a each having an alignment film (not shown) for aligning liquid crystal molecules and a transparent electrode (not shown) for applying a voltage to the liquid crystal. The liquid crystal 103 is sandwiched between 102b. Further, as shown in FIG. 5, the surface in contact with the two transparent substrates 102 a and 102 b and the liquid crystal 103 is a lens surface.

  The liquid crystal lens 101 generates an electric field between transparent electrodes (not shown) formed on the surfaces of the transparent substrates 102a and 102b facing each other by applying a voltage, and the liquid crystal lens 101 in the liquid crystal 103 is generated along the generated electric field. By arranging the liquid crystal molecules, the transparent substrates 102a and 102b and the liquid crystal 103 obtain a difference in refractive index, thereby obtaining a variable focus lens effect.

  Since the liquid crystal lens 101 shown in FIG. 5 acts as a variable focus lens due to the refractive index difference between the transparent substrates 102a and 102b having concave portions and the liquid crystal 103, switching between an infinite system and a finite system is possible. If the refractive indexes of the transparent substrates 102a and 102b and the ordinary refractive index of the liquid crystal molecules of the liquid crystal 103 are made the same, the lens effect due to the difference in the refractive index of the transparent substrates 102a and 102b and the liquid crystal 103 does not occur and becomes an infinite system. If a flat plate effect that allows the incident light 105 to the liquid crystal lens to pass through is obtained and an extraordinary refractive index component of liquid crystal molecules is expressed by voltage application, a lens effect due to the refractive index difference between the transparent substrates 102a and 102b and the liquid crystal 103 is given. It can be a finite system.

  By the way, since the Abbe number of the liquid crystal 103 is generally smaller than that of the transparent substrates 102a and 102b, the liquid crystal lens 101 generates strong chromatic aberration. Therefore, since the liquid crystal lens 101 shown in FIG. 5 has an effect as a convex lens, it can be combined with the transparent substrates 102a and 102b having the effect of a concave lens to form a liquid crystal lens with reduced chromatic aberration.

JP 61-156221 A (first page, FIG. 6)

However, the liquid crystal lens 101 shown in FIG. 5 has a converging position that changes between 400 nm light and 700 nm light as indicated by the incident light beam 105. With such a configuration, in the case of visible light in a wide wavelength band. Wavefront aberration cannot be kept small due to the effect of chromatic aberration. For example, as an index of optical performance, if the RMS value of the wavefront aberration satisfies λ / 14 or less (Marechial criterion), it is generally determined that the optical performance is sufficiently obtained with high accuracy at the diffraction limit. This configuration of the liquid crystal lens 101 is difficult to satisfy. The characteristics will be described with reference to FIG.

  FIG. 6 is a diagram showing optical characteristics of visible light in a wide wavelength band for the liquid crystal lens 101 shown in FIG. The line of wavefront aberration λ / 14 shown in FIG. 6 indicates the Martial standard that serves as an index of optical performance. Generally, the wavefront aberration generated in the liquid crystal lens 101 is λ / 14 or less. If it can be suppressed to, it is judged that the optical performance is sufficiently obtained with high accuracy of the diffraction limit.

  As shown in FIG. 5, the liquid crystal lens 101 can obtain a lens effect by applying a voltage to the liquid crystal 103. At this time, as shown in FIG. 6, in the visible light having a wide wavelength band, the incident light beam 105 having a wide wavelength band cannot be condensed at the same position due to the influence of the chromatic dispersion of the liquid crystal 103, and chromatic aberration occurs. However, it cannot satisfy λ / 14 or less, which is the diffraction limit.

  Further, in the conventional liquid crystal lens 101 shown in FIG. 5, each of the transparent substrates 102a and 102b has a lens surface. In the manufacturing process of the liquid crystal lens, the lens optical axes of both the transparent substrates 102a and 102b are accurately overlapped. It is very difficult to bond them together. If the transparent substrates 102a and 102b are bonded together while the lens optical axis is deviated, the optical axis misalignment of the lens is generated, which causes a decrease in the optical performance of the lens.

  As described above, the conventional liquid crystal lens 101 can switch between a finite system and an infinite system as a variable-focus lens, but has a problem that optical performance is remarkably deteriorated due to chromatic aberration. In addition, when the transparent substrates 102a and 102b sandwiching the liquid crystal 103 have the lens surfaces 104, the characteristics deteriorate due to the optical axis misalignment, which makes it difficult to manufacture.

  Therefore, the present invention enables dynamic switching between a finite system and an infinite system as a variable focus lens, but reliably ensures that either a finite system or an infinite system has a RMS value of wavefront aberration even in a wide wavelength band of visible light. An object of the present invention is to provide a liquid crystal lens satisfying λ / 14 or less (Marechial standard), having a high diffraction limit accuracy, sufficiently obtaining optical performance, and having an inexpensive structure and excellent mass productivity.

  In order to solve the above problems, the liquid crystal lens of the present invention basically has the following configuration.

  The liquid crystal lens of the present invention is a liquid crystal lens in which a lens surface is formed on at least one surface in contact with the liquid crystal in the two transparent substrates sandwiching the liquid crystal, and an Abbe of a member constituting the transparent substrate including the lens surface. The number is equal to the Abbe number of the ordinary light refractive index or the Abbe number of the extraordinary light refractive index in the liquid crystal.

  The liquid crystal lens of the present invention is a flat substrate in which a lens surface is formed on one of the two transparent substrates described above and a lens surface is not formed on the other substrate. It is a feature.

  The liquid crystal lens of the present invention is characterized in that the lens surface described above has a spherical or aspherical shape that is rotationally symmetric with respect to the optical axis in a plane orthogonal to the optical axis of the incident light beam. It is.

  The liquid crystal lens of the present invention is characterized in that the transparent substrate on which the lens surface is formed is a resin substrate.

  The liquid crystal lens of the present invention is characterized in that the above-described resin substrate is formed of a material containing ions having a high polarizability with respect to the main agent.

  In the liquid crystal lens of the present invention, the transparent substrate described above is a glass substrate formed of a material containing ions having a high polarizability with respect to the main agent.

  The present invention has a simple and inexpensive configuration, is excellent in mass productivity, and can be dynamically switched from a finite system to an infinite system as a variable focus lens. It is possible to provide a liquid crystal lens in which either one of the systems can reliably satisfy the RMS value of wavefront aberration of λ / 14 or less (Marechial criterion), have high diffraction limit accuracy, and sufficient optical performance.

  The configuration of the liquid crystal lens of the present invention will be described below.

  With respect to the liquid crystal lens of the first embodiment of the present invention, the configuration when the liquid crystal lens has a lens effect will be described with reference to FIG. FIG. 1 is a cross-sectional view showing the configuration of the liquid crystal lens 1 according to the first embodiment, and shows a state in which it functions as a lens.

  As shown in FIG. 1, the liquid crystal lens 1 according to the first embodiment of the present invention includes a transparent substrate 2a (transparent substrate 2a having a concave lens effect) having a resin 6 having a lens surface 4 formed on a surface in contact with the liquid crystal 3. And a transparent substrate 2b (a flat substrate) that does not have a lens shape. Here, the lens surface 4 is formed on only one surface of the liquid crystal 3 in a spherical or aspherical shape that is rotationally symmetric with respect to the optical axis in a plane orthogonal to the optical axis of the incident light beam 5a. Whether the lens surface 4 is a spherical surface or an aspherical surface is arbitrary depending on the design specification. Further, the lens surface 4 greatly affects the thickness of the liquid crystal 3 due to the curvature, and thus greatly affects the response of the liquid crystal lens 1. Therefore, in order to reduce the thickness of the liquid crystal 3, the lens surface 4 may have a Fresnel lens shape. Furthermore, not only the transparent substrate 2a having the concave lens effect shown here but also a form having a convex lens effect according to the specification may be used.

  Further, the transparent substrate 2a having the lens surface 4 and the opposing transparent substrate 2b are sandwiched between the substrates by transparent electrodes (not shown) and alignment films (not shown) formed on the respective substrate surfaces. By supplying power to the liquid crystal 3, a difference in refractive index from the liquid crystal 3 can be given to the incident light 5 a on the lens surface 4 of the resin 6.

  Further, in the liquid crystal lens 1 shown in FIG. 1, the resin 6 on which the lens surface 4 is formed has a high refractive index and a low Abbe number, for example, containing ions having a high polarizability with respect to the main agent made of acrylic resin. The material is adopted. Since the polarizability shown here represents the susceptibility of the substance to light displacement, the higher the polarizability, the higher the refractive index. The resin 6 used here is a polymer material having, for example, a benzene ring, sulfur, iodine, bromine or the like, which is an organic group exhibiting a high polarizability, so that the refractive index is higher than the refractive index of the resin material. Can be adjusted to the rate. Further, when the lens surface 4 is formed of the polymer material having the organic group as described above to increase the refractive index, the influence of dispersion due to the wavelength of the incident light beam 5a incident on the liquid crystal lens 1 increases. It should be noted that a refractive index material necessarily results in a low Abbe number material with large chromatic dispersion.

  In the liquid crystal lens 1 according to the first embodiment of the present invention shown in FIG. 1, nematic liquid crystal having homogeneous alignment is used as the liquid crystal 3, but vertical alignment type liquid crystal can also be used. In any alignment mode, the extraordinary refractive index Ne of the liquid crystal 3 is made to coincide with the refractive index of the resin 6. By doing so, when the liquid crystal molecules are driven so as to be parallel to the transparent substrate 2b (up and down with respect to the paper surface) as shown in FIG. 1, the ordinary refractive index No of the liquid crystal 3 acts on the incident light beam 5a. Therefore, the liquid crystal lens 1 can have a lens effect because the incident light 5a is refracted by the lens surface 4 due to the difference between the ordinary refractive index No of the liquid crystal 3 and the refractive index of the resin 6.

  Further, since the refractive index of the liquid crystal 3 is different for each of the extraordinary refractive index Ne and the ordinary refractive index No, the Abbe number indicating the magnitude of chromatic dispersion is inevitably different. Therefore, if the liquid crystal lens is formed without considering the Abbe number of the resin material that acts as the liquid crystal 3 and the lens, the extraordinary refractive index Ne having a large refractive index is more wavelength-dispersed than the ordinary refractive index No having a small refractive index. However, the Abbe number of the extraordinary light refractive index Ne is smaller than the Abbe number of the resin 6. Therefore, in the present invention, the Abbe number at the ordinary light refractive index No of the liquid crystal 3 and the Abbe number of the resin 6 having a high refractive index are substantially matched. At this time, naturally, the Abbe number of the extraordinary refractive index Ne of the liquid crystal 3 and the Abbe number of the resin 6 are different values.

  Therefore, in order to match the Abbe number of the resin 6 with the Abbe number in the ordinary light refractive index No of the liquid crystal 3, specifically, the Abbe number in the ordinary light refractive index No of the liquid crystal 3 is around 35. The refractive index and the Abbe number are adjusted using the above-described polymer material having an organic group with a high polarizability. At this time, since the refractive index of the resin 6 can be adjusted in the range of about 1.6 to 1.9 and the Abbe number is about 20 to 40, if the Abbe number of the resin 6 is adjusted to about 35, It almost coincides with the Abbe number of the ordinary light refractive index No of the liquid crystal 3.

  Moreover, since the ordinary light refractive index No of the liquid crystal 3 is around 1.5, and the refractive index of the resin material is around 1.6 to 1.9, the difference in refractive index between them is about 0.1 to 0.4. Will be. The liquid crystal lens 1 can realize a variable focus lens having no chromatic aberration within the range of the refractive index difference.

  As described above, the liquid crystal lens 1 according to the first embodiment of the present invention shown in FIG. 1 has this ordinary light refraction even when the ordinary light refractive index No is applied when the liquid crystal 3 is driven so as to have a lens effect. Since the Abbe number at the rate No matches the Abbe number of the resin 6, even if it is the incident light ray 5a in a wide wavelength band from 400 nm to 700 nm, as shown in FIG. The light is condensed at the same position, and as a result, chromatic aberration can be suppressed.

  Next, the liquid crystal lens 1 according to the present invention will be described with reference to FIG. 2 in the form when the liquid crystal lens 1 has a flat plate effect (when the liquid crystal 3 is not driven). FIG. 2 is a diagram showing the liquid crystal lens 1 when the lens effect shown in FIG. 1 is switched to the flat plate effect.

  As described above, in the liquid crystal lens 1 of the present invention, the ordinary refractive index No of the liquid crystal 3 is matched with the refractive index of the resin 6. Therefore, when the liquid crystal molecules are driven so as to be perpendicular to the transparent substrate 2b as shown in FIG. 2, the extraordinary refractive index Ne of the liquid crystal 3 acts on the incident light beam 5b, and the configuration shown in FIG. Unlike the above, the incident light 5b is not refracted on the lens surface 4, and the liquid crystal lens 1 can act as a flat plate to allow the incident light 5b to pass through.

However, the liquid crystal lens 1 according to the first embodiment of the present invention shown in FIG. 2 has this extraordinary light refractive index Ne acting when the liquid crystal 3 is driven so as to have a flat plate effect. Since the Abbe number at the refractive index Ne and the Abbe number of the resin 6 are different, as shown in FIG. 2, the incident light beam 5b in a wide wavelength band cannot collect the light of each wavelength at the same position. It becomes difficult to suppress chromatic aberration.

  Next, the performance of the liquid crystal lens 1 of the present invention will be described. FIG. 3 shows the wavefront aberration of a light beam emitted from the liquid crystal lens 1 when an incident light beam having a wide wavelength band is incident on the liquid crystal lens 1 according to the present invention described with reference to FIGS. In the figure, the vertical axis represents the amount of wavefront aberration, and the horizontal axis represents the wavelength. Further, the solid line shown in this figure indicates the wavefront aberration when the liquid crystal lens 1 has a lens effect, and the dotted line indicates the wavefront aberration when the liquid crystal lens 1 has a flat plate effect. Further, the line of wavefront aberration λ / 14 shown in FIG. 3 indicates a Martial standard that is an index of optical performance. Generally, if the wavefront aberration can be suppressed to λ / 14 or less. Therefore, it is determined that the optical performance is sufficiently obtained with high accuracy at the diffraction limit.

  As shown in FIG. 3, when the liquid crystal lens 1 according to the present invention has a lens effect, the diffraction limit λ / 14 can be satisfied. This is because, as described above, since the Abbe number at the ordinary light refractive index No and the Abbe number of the resin 6 are substantially the same, the chromatic aberration of the light transmitted through the liquid crystal lens 1 can be suppressed as much as possible. .

  It can also be seen that when the liquid crystal lens 1 in the present invention has a flat plate effect, it is difficult to satisfy λ / 14 which is a diffraction limit. Also as described above, at this time, since the Abbe number at the extraordinary light refractive index Ne and the Abbe number of the resin 6 are different, it is difficult to suppress the chromatic aberration of the light transmitted through the liquid crystal lens 1.

  In the first embodiment of the present invention, the wavefront aberration is reduced when the liquid crystal lens 1 has a lens effect so that the wavefront aberration is minimized. However, in accordance with the actual application of the liquid crystal lens 1, it is possible to minimize the wavefront aberration during the flat plate effect. In order to minimize the wavefront aberration during the flat plate effect, the effect can be obtained if the Abbe number of the resin 6 is set to coincide with the Abbe number in the extraordinary light refractive index Ne of the liquid crystal 3. .

  As described above, the liquid crystal lens 1 according to the first embodiment of the present invention enables the liquid crystal lens 1 to be dynamically switched from a finite system to an infinite system, and is in a visible range in accordance with each application of the liquid crystal lens. Therefore, it is possible to suppress the occurrence of chromatic aberration as much as possible to incident light in a wide wavelength band, and to suppress the wavefront aberration to the diffraction limit. In addition, since the configuration of the present invention has a single lens surface, the problem of optical axis misalignment does not occur, so that a liquid crystal lens with an inexpensive configuration and excellent mass productivity can be provided.

  In order to suppress chromatic aberration as much as possible in both the lens effect and the flat plate effect, the Abbe number of the material forming the lens surface is set to the Abbe number in the ordinary light refractive index No of the liquid crystal and the Abbe number in the extraordinary light refractive index Ne. What is necessary is just to adjust so that it may become intermediate.

  In the present embodiment, the configuration example in which the lens surface 4 is formed on the one transparent substrate 2b side is shown. However, a lens surface may be provided on the surface of the transparent substrate 2a on the other surface as necessary. . With this configuration, there is an increased possibility that the optical axis misalignment of the lens will occur in the manufacturing process of the liquid crystal lens as compared with the configuration of FIGS. It is possible to achieve a form in which the occurrence of chromatic aberration is suppressed as much as possible while widening the degree of freedom in lens design, such as reducing the chromatic aberration or increasing the lens effect.

  Next, another configuration of the liquid crystal lens according to the first embodiment of the present invention will be described with reference to FIG. 4 when the liquid crystal lens has a lens effect. FIG. 4 is a cross-sectional view illustrating a configuration of the liquid crystal lens 11 according to the second embodiment, and illustrates a state in which the liquid crystal lens 11 has acted as a lens.

  As shown in FIG. 4, the liquid crystal lens 11 according to the second embodiment of the present invention includes a transparent substrate 12 a in which a lens surface 14 is formed on a surface in contact with the liquid crystal 13, and an opposing transparent substrate 12 b. Also in this embodiment, the lens surface 14 is formed on one surface with respect to the liquid crystal 13 in a spherical or aspherical shape that is rotationally symmetric with respect to the optical axis in a plane orthogonal to the optical axis of the incident light beam 15a. Yes. Whether the lens surface shape is a spherical surface or an aspherical surface shape is arbitrary depending on the specification application. Furthermore, since the lens surface 14 greatly affects the thickness of the liquid crystal 13 due to the curvature, it greatly affects the response of the liquid crystal lens 11. Therefore, in order to reduce the thickness of the liquid crystal 13, the lens surface 14 may have a Fresnel lens shape.

  The transparent substrate 12a having the lens surface 14 and the opposing transparent substrate 12b are sandwiched between the substrates by a transparent electrode (not shown) and an alignment film (not shown) formed on the respective substrate surfaces. By supplying power to the liquid crystal 13, a difference in refractive index from the liquid crystal 13 can be given to the incident light 15 a on the lens surface 14.

  Moreover, in the liquid crystal lens 11 of the second embodiment of the present invention shown in FIG. 4, the transparent substrate 12a having the lens surface 14 is a glass substrate and has a high refractive index including ions having a high polarizability with respect to the main agent. There is a material with a low Abbe number. Since the polarizability shown here represents the susceptibility of the substance to light displacement, the higher the polarizability, the higher the refractive index. About this transparent substrate 12a, it can be set as the transparent substrate 12a which has a high refractive index, for example by adjusting content of lead and barium which show high polarizability in glass material. Also, if the transparent substrate 12a has a high refractive index, the influence of dispersion due to the wavelength of the incident light becomes large, so that a material with a high refractive index inevitably becomes a low Abbe number material with a large wavelength dispersion. There is.

  Also, in the liquid crystal lens 11 of the second embodiment of the present invention shown in FIG. 4, nematic liquid crystal having homogeneous alignment is used as the liquid crystal 13, but vertical alignment type liquid crystal can also be used. In any orientation mode, the extraordinary light refractive index Ne of the liquid crystal 13 is made to coincide with the refractive index of the transparent substrate 12a. By doing so, when the liquid crystal molecules are driven so as to be parallel to the transparent substrate 12b (up and down with respect to the paper surface) as shown in FIG. 4, the ordinary light refractive index No of the liquid crystal 13 acts on the incident light 15a. Therefore, the incident light 15a is refracted by the lens surface 14 due to the difference between the ordinary refractive index No of the liquid crystal 13 and the refractive index of the transparent substrate 12a, so that the liquid crystal lens 11 can have a lens effect.

  Further, since the liquid crystal 13 has a different refractive index in each of the extraordinary refractive index Ne and the ordinary refractive index No, the Abbe number indicating the magnitude of chromatic dispersion inevitably also differs. Therefore, when the liquid crystal lens is formed without considering the liquid crystal 13 and the transparent substrate material that acts as a lens, the extraordinary refractive index Ne having a large refractive index has a larger wavelength dispersion than the ordinary refractive index No having a small refractive index. Although the Abbe number is low, the Abbe number of the extraordinary refractive index Ne is smaller than the Abbe number of the transparent substrate 12a. Therefore, in the present invention, the Abbe number at the ordinary light refractive index No and the Abbe number of the transparent substrate 12a having a high refractive index are substantially matched. At this time, as a matter of course, the Abbe number of the extraordinary refractive index Ne of the liquid crystal 13 and the Abbe number of the transparent substrate 12a are different values.

Therefore, in order to match the Abbe number of the transparent substrate 12a with the Abbe number in the ordinary light refractive index No of the liquid crystal 13, specifically, the Abbe number in the ordinary light refractive index No of the liquid crystal 13 is about 35. The refractive index and the Abbe number are adjusted by adjusting the content of lead or barium having a high polarizability described above for 12a. At this time, since the refractive index of the transparent substrate 12a can be adjusted in the range of about 1.6 to 1.9 and the Abbe number is in the range of about 20 to 40, the Abbe number of the transparent substrate 12a is adjusted to be about 35. For example, the Abbe number of the ordinary light refractive index No of the liquid crystal 13 is substantially equal. Moreover, since the ordinary light refractive index No of the liquid crystal 13 is around 1.5, and the refractive index of the resin material is around 1.6 to 1.9, the refractive index difference between them is about 0.1 to 0.4. Will be. The liquid crystal lens 11 can realize a variable focus lens having no chromatic aberration within the range of the refractive index difference.

  As described above, the liquid crystal lens 11 of the present invention shown in FIG. 4 has the Abbe number at the normal light refractive index No, even when the normal light refractive index No acts when the liquid crystal 13 is driven so as to have a lens effect. Since the Abbe number of the transparent substrate 12a matches, as shown in FIG. 4, even if the incident light 15a has a wide wavelength band from 400 nm to 700 nm, all the light of each wavelength is condensed at the same position. Thus, chromatic aberration can be suppressed.

  The relationship between the wavefront aberration when the liquid crystal lens 11 according to the second embodiment of the present invention has a lens effect and the wavefront aberration when it has a flat plate effect is described with reference to FIGS. 2 have the same effects as those of No. 2 and will not be described here.

  Further, as described above, the liquid crystal lens 11 in the second embodiment is also configured to minimize the wavefront aberration when having a lens effect. However, in accordance with the actual use of the liquid crystal lens 11, it is possible to minimize the wavefront aberration during the flat plate effect. In order to minimize the wavefront aberration during the flat plate effect, the effect can be obtained if the Abbe number of the transparent substrate 12a is set to coincide with the Abbe number in the extraordinary refractive index Ne of the liquid crystal 13. it can.

  As described above, the liquid crystal lens 11 according to the second embodiment of the present invention can also dynamically switch the liquid crystal lens 11 from the finite system to the infinite system. It is possible to suppress the occurrence of chromatic aberration as much as possible to incident light in a wide wavelength band, and to suppress wavefront aberration to the diffraction limit. In addition, since the configuration of the present invention has a single lens surface, the problem of optical axis misalignment does not occur, so that a liquid crystal lens with an inexpensive configuration and excellent mass productivity can be provided.

It is sectional drawing when the liquid-crystal lens of 1st embodiment in this invention has a lens effect. It is sectional drawing when the liquid-crystal lens of 1st embodiment in this invention has a flat plate effect. It is a figure showing the wavefront aberration at the time of the liquid-crystal lens of this invention having a lens effect and a flat plate effect, respectively. It is sectional drawing when the liquid-crystal lens of 2nd embodiment in this invention has a lens effect. It is sectional drawing which shows the structure of the conventional liquid crystal lens. It is a figure showing the wavefront aberration at the time of the conventional liquid crystal lens having a lens effect.

Explanation of symbols

1, 11, 101 Liquid crystal lens 2a, 2b, 12a, 12b Transparent substrate 3, 13 Liquid crystal 4, 14 Lens surface 5a, 5b, 15a Incident light 6 Resin

Claims (6)

In a liquid crystal lens in which a lens surface is formed on at least one surface in contact with the liquid crystal in the two transparent substrates sandwiching the liquid crystal,
A liquid crystal lens characterized in that an Abbe number of a member constituting the transparent substrate including the lens surface is equal to an Abbe number of an ordinary light refractive index or an Abbe number of an extraordinary light refractive index in the liquid crystal. The lens substrate is formed on one of the two transparent substrates, and the other substrate is a flat substrate on which no lens surface is formed. Liquid crystal lens. The liquid crystal lens according to claim 1, wherein the lens surface has a spherical or aspherical shape that is rotationally symmetric with respect to the optical axis in a plane orthogonal to the optical axis of the incident light beam. The liquid crystal lens according to any one of claims 1 to 3, wherein the transparent substrate on which the lens surface is formed is a resin substrate. The liquid crystal lens according to claim 4, wherein the resin substrate is made of a material containing ions having a high polarizability with respect to the main agent. The liquid crystal according to any one of claims 1 to 3, wherein the transparent substrate on which the lens surface is formed is a glass substrate formed of a material containing ions having a high polarizability with respect to the main agent. lens.

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