JP2007218960A - Varifocal spectacles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide varifocal spectacles which have optical elements of solid crystal with variable optical characteristics formed on a surface of a transmissive substrate at equally spaced cycles and to which vibrations are applied from outside. <P>SOLUTION: The varifocal spectacles have the optical elements of a solid crystal film with variable optical characteristics formed at equally spaced cycles and a means of applying vibrations from outside on at least the one transmissive substrate surface supported on a spectacle frame 4, and the focal length is varied by varying the optical characteristics by applying external vibrations. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to varifocal spectacles in which a transmissive substrate is provided with a variable optical element of solid crystal optical characteristics.

  The present invention relates to varifocal spectacles provided with a solid crystal optical property variable optical element, and more particularly to varifocal spectacles in which a solid crystal optical property variable element is formed on a transparent substrate surface at regular intervals. Is.

  The present invention relates to varifocal spectacles in which a variable optical element of a solid crystal is formed on a transmissive substrate surface at regular intervals, and more specifically, the optical characteristics of a solid crystal formed at regular intervals. The present invention relates to variable focus glasses that apply vibration to the variable element from the outside.

  The present invention relates to variable focus spectacles that externally apply vibration to a solid crystal optical property variable element formed at equal intervals, and to apply optical vibration to the solid crystal optical property variable element from the outside, thereby improving the optical characteristics. The present invention relates to a technique that can change and change the focus.

Variable focus glasses used as bifocal glasses include two lenses with different focal points in a single lens, a method that switches by rotating the single lens, a method that switches by switching the single lens up and down, and glasses A method has been proposed in which itself is turned upside down. As a new system, there is variable focus glasses using a variable dielectric such as a liquid crystal or a solid crystal film as a lens. Variable focus glasses using variable dielectrics such as liquid crystals and solid crystal films apply a voltage to the variable dielectric placed in the lens and adjust the applied voltage to change the refractive index and wear It adjusts the focus position of the eyeglasses seen from the person. (For example, see Patent Document 1 and Patent Document 2)
JP-A-63-135916 JP-A-11-352445

In conventional variable-focus eyeglasses with two lenses with different focal points in a single lens used for both near and near, the image is distorted at the boundary because one lens is divided by the surface. In other words, there is a problem that it becomes an obstacle during use, and half of the focus is out of focus and the field of view is narrowed. Moreover, in conventional variable focus glasses using liquid crystal, the liquid crystal is sealed in the lens, so if an impact is applied from the outside due to dropping or collision, the liquid crystal leaks and the focus is not adjusted, so There was a problem that the function could not be demonstrated. Furthermore, variable focus glasses using a solid crystal film have a problem that a change in refractive index induced by application of an electric field is small.

  SUMMARY OF THE INVENTION The present invention solves the conventional problems, and provides variable-focus spectacles in which solid crystal optical property variable optical elements are formed on a transparent substrate surface at regular intervals, and vibrations are applied thereto from the outside. With the goal.

  In order to solve the above-described conventional problems, variable focus glasses for applying vibration from the outside to a solid crystal optical property variable optical element formed on a transparent substrate surface of the present invention at regular intervals are provided on a spectacle frame. Vibration is applied to the optical characteristic variable optical element in which solid crystals are formed at regular intervals on the surface of at least one transparent substrate to be supported, and to the optical characteristic variable optical element in which solid crystals are formed at regular intervals. It is possible to change the focal point by changing the optical characteristics of the optical characteristic variable optical element in which the solid crystals are formed at equal intervals by applying external vibration. Therefore, since it can be used for both convex lenses and concave lenses, the influence of image distortion, dropping, and external impact at the boundary portions that existed in the past can be mitigated. In addition, it is possible to amplify a change in refractive index due to the application of an electric field, which was weak with variable focus glasses using a solid crystal film, and the film thickness is reduced.

According to the variable focus glasses for applying vibration from the outside to the optical characteristic variable optical element of the solid crystal formed on the transparent substrate surface of the present invention at regular intervals, the optical characteristics are changed by applying external vibration, It becomes possible to change the focus. Therefore, since it can be used for both convex lenses and concave lenses, the influence of image distortion, dropping, and external impact at the boundary portions that existed in the past can be mitigated. In addition, it is possible to amplify a change in refractive index due to the application of an electric field, which was weak in variable focus glasses using a solid crystal film, and it is possible to provide glasses with a thin film thickness.

  Hereinafter, embodiments of variable focus glasses of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of a method for manufacturing a lens used in the variable focus glasses of the present invention. 1 is a plastic lens as a transparent substrate, 2A and 2B are ITO thin films as means for applying a voltage, and 3A, 3B, 3C and 3D are barium titanates which are metal oxides as solid crystals. After placing the plastic lens 1 on the sample stage of the magnetron sputtering apparatus (manufactured by ULVAC), the inside of the chamber is depressurized to 5 × 10 ⁻⁵ Pa, and then a gas in which argon and some oxygen gas are mixed is introduced. 7 Pa. First, in order to provide means for applying a voltage, ITO (indium tin oxide) was used as a target, the set temperature in the apparatus was set to 250 ° C., and an ITO thin film 2A having a thickness of 10 to 100 nm was formed.

  The substrate on which the ITO thin film 2A was formed was mounted on a spin coater (Mikasa). A positive photoresist (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was dropped with a micropipette so as to cover the entire substrate. The spin coater is set to rotate at 1000 rpm for 20 seconds, over the next 20 seconds at a high speed from 1000 rpm to 5000 rpm, held at 5000 rpm for 20 seconds, and then stopped for 5 seconds to obtain uniform photo A resist film was applied. The substrate coated with the resist film was placed on a hot plate set at 95 ° C. for 90 seconds, and prebaked. Using an exposure apparatus (manufactured by JEOL Ltd.) in which the gap distance between the photomask and the substrate is set to 100 μm and the applied voltage is set to 3 keV, a stripe-shaped pattern having a width of 200 nm and a period of 700 nm is formed on the substrate after pre-baking. It was immersed in an alkali developer (manufactured by Tokyo Ohka Kogyo Co., Ltd.) and developed. After that, it was washed twice with pure water stored in a beaker and washed with running water, sprayed with nitrogen gas and dried, and the dried substrate was placed on a hot plate set at 120 ° C. for 5 minutes and post-baked. It was.

  As a method for forming a thin film of solid crystals on the stripe-shaped pattern formed earlier, 12. in 50 ml of a solvent in which methanol (manufactured by Wako Pure Chemical Industries, Ltd.) and 2-methoxyethanol (manufactured by Wako Pure Chemical Industries, Ltd.) are mixed. After dissolving 78 g of barium isopropoxide (manufactured by Wako Pure Chemical Industries, Ltd.) and 11.41 g of titanium ethoxide (manufactured by Wako Pure Chemical Industries, Ltd.), the solution was cooled to -20 degrees Celsius and the amount of water vapor was stirred. Was adjusted in the range of 3 to 8 mol in small portions to prepare a sol solution. The prepared sol solution was dropped with a micropipette so as to cover the entire substrate on which the stripe-shaped pattern was produced. As a spin coater setting, the sol solution was rotated by rotating at 1000 rpm for 20 seconds, increasing the speed from 1000 rpm to 5000 rpm over the next 30 seconds, holding at 5000 rpm for 60 seconds, and then stopping rotation for 5 seconds. It was applied evenly.

  The substrate on which the sol solution was applied was heated in a furnace at 200 ° C. for 1 hour to remove moisture, and then it was confirmed that the temperature had been raised to 500 ° C., followed by heating for 2 hours and firing. The substrate is taken out from the furnace, installed in an exposure apparatus, exposed to the entire substrate, and subjected to ultrasonic cleaning in an organic alkali developer to remove the resist remaining on the substrate. As shown in FIG. The barium titanate crystal 3A was formed at regular intervals.

  In order to form the second layer of periodic barium titanate crystals at regular intervals, a photomask installed in the exposure apparatus using the same conditions as those for producing the first layer of periodic barium titanate crystals. As shown in FIG. 1 (b), the direction of the barium titanate crystal 3A formed at equal intervals in the first layer is rotated by 90 degrees and the stripe shape of the first layer is orthogonal. Then, a second-layer stripe-shaped barium titanate crystal 3B having a period of 700 nm was formed.

  In order to form the periodic periodic barium titanate crystal of the third layer at regular intervals, the photo is installed in the exposure apparatus under the same conditions as those for the periodic periodic barium titanate crystal of the second layer. The mask does not overlap with the stripe shape of the periodic barium titanate crystal of the first layer, and the direction of the periodic barium titanate crystal 3B of the second layer is rotated by 90 degrees, A striped barium titanate crystal 3C of the third layer having a width of 200 nm and a period of 700 nm as shown in FIG. 1C was formed under the condition that the shape was orthogonal.

  In order to form the fourth layer of periodic barium titanate crystals at regular intervals, a photo that is installed in the exposure apparatus using the same conditions as those for the third layer of periodic barium titanate crystals. The mask does not overlap with the stripe shape of the periodic barium titanate crystal of the second layer, and the direction of the periodic barium titanate crystal 3C of the third layer is rotated by 90 degrees, The stripe-shaped barium titanate crystal 3D was formed in a fourth layer having a width of 200 nm and a period of 700 nm as shown in FIG.

First, in order to provide means for countering the ITO thin film 2A formed as means for applying a voltage, a substrate having a four-layer stripe shape as shown in FIG. The pressure inside the chamber was reduced to 5 × 10 ⁻⁵ Pa, and a gas mixed with argon and some oxygen gas was introduced to 0.7 Pa. Using ITO (indium tin oxide) as a target, the set temperature in the apparatus was 250 ° C., and an ITO thin film 2B having a thickness of 10 to 100 nm was formed on the stripe shape as shown in FIG.

  In FIG. 1, a sol-gel method is used to form a barium titanate crystal film on a plastic lens. However, a stripe shape is formed by sputtering, laser ablation, organometallic compound deposition, or organometallic vapor deposition. It is also possible to stack three-dimensionally in a three-dimensional manner by stacking in three dimensions or by self-cloning. Further, although a plastic lens is used as the transmissive substrate, a glass lens or a sapphire lens can also be used.

  FIG. 2 is a diagram showing an example of light absorption characteristics of a barium titanate crystal film formed at regular intervals in one example of the variable focus glasses of the present invention. The horizontal axis is the wavelength of light input to the barium titanate crystal film formed at equal intervals on the plastic lens produced above, and the vertical axis is the absorptance expressed as a logarithm of the ratio of the output light intensity to the input light intensity. is there. Although the input light is almost absorbed at a short wavelength of about 200 nm, the rate of absorption decreases as the wavelength increases. When the period of the barium titanate crystal is 700 nm or more, the input light is hardly absorbed.

  FIG. 3 is a schematic diagram of the variable focus glasses of the present invention. 4 is a spectacle frame, 5 is a plastic lens, 6A and 6B are ITO thin films, 7 is a barium titanate crystal film, and 8 is a power source.

  In the barium titanate crystal film 7, barium 9A, titanium 10A and oxygen atoms 11A have a crystal structure as shown in FIG. When an electric field 12 is applied to the barium titanate crystal film 7 through the ITO films 6A and 6B connected to the power supply 8, barium 9B (positive), titanium 10B (positive) and oxygen 11B (negative) forming the crystals are formed. Since each atom has a positive or negative electrical bias, the structure expands and contracts as shown in FIG. 4B in response to the electric field, and the center of the crystal structure shifts. When the center of the crystal structure is shifted, an electric field induced strain is generated, and as a result, the optical characteristics are changed.

  FIG. 5 shows an example of the electrochemical characteristics of a barium titanate crystal film formed at regular intervals by applying an electric field in an example of variable focus glasses of the present invention. In FIG. 5, the horizontal axis is the electric potential gradient obtained by dividing the electric field strength applied from the power source by the thickness of the barium titanate crystal film formed on the transparent substrate, and the vertical axis is the applied electric potential gradient at a wavelength of 400 nm. Is a change in dielectric constant (%) obtained by dividing the difference between the dielectric constant of the electric field and the dielectric constant of the unapplied electric field (0 V / mm) by the dielectric constant of the non-applied electric field (0 V / mm). When the potential gradient was applied to the barium titanate crystal film while increasing the potential gradient from 0 to 200 V / mm, the amount of change in dielectric constant started to change from around 150 V / mm. In addition, when applied by running while decreasing the potential gradient from 200 V / mm to 0 V / mm, the dielectric constant changes reversibly as when no electric field is applied, although it draws asymmetric optical characteristics. Returned to the amount (%).

FIG. 6 is a diagram showing an example of the dielectric characteristics of a barium titanate crystal film formed at regular intervals when a potential gradient of 200 V / mm is applied in an example of variable focus glasses of the present invention. The horizontal axis represents the wavelength of light input to the barium titanate crystal film formed on the plastic lens produced at regular intervals, and the vertical axis represents the refraction estimated from the light absorption characteristics shown in FIG. 2 when no voltage is applied. The change in dielectric constant (%) obtained by dividing the difference from the dielectric constant at a wavelength of 400 nm by the dielectric constant at a wavelength of 400 nm, the solid line is the dielectric characteristic when a potential gradient of 200 V / mm is applied, and the dotted line is the potential gradient applied Dielectric characteristics when not. With respect to the wavelength range of the potential gradient from 400 to 700 nm, applying an electric field induces a change in dielectric constant at each wavelength.
In this way, it is possible to create different optical characteristics by applying an electric field in glasses with a barium titanate crystal film formed at regular intervals on a plastic lens, and it can be used for both concave and convex lenses. can do. For this reason, image distortion and liquid crystal at the boundary of the lens, which was generated with spectacles with two lenses with different focal points in a single lens used for presbyopia caused by muscle weakness near the eyeball, were used. The influence of the change in the focal length due to the liquid crystal leakage that occurred in the glasses that was worn is alleviated. In addition, it is possible to amplify a change in refractive index due to the application of an electric field, which was weak in variable focus glasses using a solid crystal film, and it is possible to provide glasses with a thin film thickness.

  FIG. 7 shows an example of the number of recognizable images according to the electric field running speed in an example of the variable focus glasses of the present invention. The horizontal axis is the electric field running speed (V / s), and the vertical axis is the number of recognized images. If the running speed is 800 V / s or less, it is possible to recognize the two images of far and near separately, but if the running speed is about 2000 V / s, the far and near two images The boundaries of the image become ambiguous and difficult to recognize. If the running speed is further increased to 4000 V / s or more, the two images of the far and near images can be recognized, but they are recognized as one image in which both the far and near images are combined. This makes it possible to recognize both the far and near images simultaneously without recognizing the far and near images via a switch or the like as necessary.

In the variable focus glasses, barium titanate was used as the solid crystal film, but potassium dihydrogen phosphate (KH ₂ PO ₄ ), potassium dihydrogen phosphate (KD ₂ PO ₄ ), lithium niobate (LiNbO ₃ ). It is possible to use a material whose optical properties change when an electric field such as zinc oxide (ZnO) or KTN crystal is applied. In addition, although the equally spaced period is set to 700 nm, the period is not limited to 700 nm and may be other periods, and is preferably 700 nm or less so that a large change in dielectric constant can be obtained.

According to the varifocal spectacles in which vibration is applied from the outside to the optical characteristic variable optical element of the solid crystal film formed on the transparent substrate of the present invention at equal intervals, the optical characteristic is changed by applying external vibration, and the focus is changed. Can be changed. For this reason, it can be used for both convex and concave lenses, so it not only relieves image distortion at the boundary that existed in the past, but also provides eyeglasses that are resistant to external impacts such as drops and impacts. it can. In addition, it is possible to amplify a change in refractive index due to the application of an electric field, which was weak in variable focus glasses using a solid crystal film, and it is possible to provide glasses with a thin film thickness.

The schematic diagram which shows an example of the production method of the optical element used for the variable focus spectacles of this invention The figure which shows an example of the light absorption characteristic of the barium titanate crystal film formed in the interval of equal intervals in an example of the variable focus spectacles of this invention Schematic diagram of variable focus glasses of the present invention FIG. 4 is a schematic diagram showing an example of a crystal structure of a barium titanate crystal film in an example of the variable focus glasses of the present invention, (a) a schematic diagram showing a crystal structure in a state where no electric field is applied from the outside, and (b) an external view. Schematic diagram showing the crystal structure with an electric field applied The figure which shows an example of the electrochemical characteristic of the barium titanate crystal film by application of an electric field in an example of the variable focus spectacles of this invention The figure which shows an example of the dielectric constant characteristic of the barium titanate crystal film formed in the period of equal intervals at the time of applying a potential gradient 200V / mm in an example of the variable focus spectacles of this invention. The figure which shows an example of the number of the images which can be recognized according to the running speed of an electric field in an example of the variable focus spectacles of this invention.

Explanation of symbols

1, 5 Plastic lens 2A, 2B, 6A, 6B ITO thin film 3A, 3B, 3C, 3D, 7 Barium titanate crystal 4 Eyeglass frame 8 Power supply 9A, 9B Barium atom 10A, 10B Titanium atom 11A, 11B Oxygen atom 12 Electric field

Claims (7)

An eyeglass frame, a transparent base on at least one of the eyeglass frames, an optical element in which a solid crystal is provided on the transparent base, and a vibration applying unit that applies vibration to the optical element from the outside are disposed. In the variable-focus glasses, the solid-crystals are arranged on the transparent substrate surface at regular intervals, and at least one of the arrays is formed. 2. The variable focus glasses according to claim 1, wherein the solid crystal has a perovskite structure. Examples of solid crystals having the perovskite structure include barium titanate (BaTiO ₄ ), potassium dihydrogen phosphate (KH ₂ PO ₄ ), potassium double hydrogen phosphate (KD ₂ PO ₄ ), lithium niobate (LiNbO ₃ ). 3. The variable focus glasses according to claim 2, wherein the glasses are zinc oxide (ZnO) or KTN crystal. The variable focus glasses according to any one of claims 1 to 3, wherein the equally spaced period is 700 nm or less. The variable focus glasses according to any one of claims 1 to 4, wherein the vibration applying means for applying vibration from the outside is a means for applying at least one of an electric field or a magnetic field. 6. The variable focus glasses according to claim 5, wherein the means for applying vibration by the electric field is means for applying a potential gradient of 150 V / mm or more. 7. The variable focus glasses according to claim 6, wherein the means for applying a potential gradient of 150 V / mm or more is a means for applying a running speed of 4000 V / s or more.

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