JPH1164817A - Variable focusing lens, variable focusing diffraction optical element and variable polarizing angle prism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable focusing lens which can improve the utilization efficiency of light and improves versatility so as to be effectively applied to various optical products. SOLUTION: This lens has 1st and 2nd planes 8a and 8b, for example, a 1st optical member 12a for transmitting incident light through the 1st and 2nd planes 8a and 8b, a 2nd optical member 12b having a 3rd plane 9a for receiving the light transmitted through the 1st optical member 12a, a lens plane formed on one of 1st, 2nd and 3rd planes 8a, 8b and 9a at least, a pair of transparent electrodes 13a and 13b respectively provided on the side of 2nd and 3rd planes 8b and 9a, and polymeric distributed liquid crystal layer 14 provided between these transparent electrodes 13a and 13b. By impressing electric fields through a pair of transparent electrodes 13a and 13b to the polymeric distributed liquid crystal layer 14, the focal position of light transmitted through the 1st and 2nd optical members 12a and 12b or light transmitted through the 1st optical member 12a, reflected on the 3rd plane 9a and transmitted through the 1st optical member 12a again can be varied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable focus lens, a variable focus diffractive optical element, and a variable deflection prism as liquid crystal optical elements.

[0002]

2. Description of the Related Art Conventionally, in constructing a variable focus lens system, when a lens manufactured by polishing glass is used as a lens, it is difficult to change the focal length by itself. For example, as in a zoom lens of a camera, a part of a lens group is moved in an optical axis direction to change a focal length of a lens system. However, such a configuration has a disadvantage that the mechanical structure is complicated.

In order to solve such a problem,
For example, as shown in FIG.
An optical system using the following has been proposed. Here, the liquid crystal lens 2 has lenses 3a and 3b and a liquid crystal layer 5 provided between the lenses via transparent electrodes 4a and 4b, and an AC power supply via a switch 6 between the transparent electrodes 4a and 4b. 7 and by selectively applying an electric field to the liquid crystal layer 5,
It is configured to change the refractive index.

In such an optical system, for example, when natural light is incident on the polarizing plate 1, only a predetermined linearly polarized light component is transmitted through the polarizing plate 1 and is incident on the liquid crystal lens 2. Here, as shown in FIG. 18, when the switch 6 is turned off and no electric field is applied to the liquid crystal layer 5, the major axis of the liquid crystal molecules 5a is oriented in the same direction as the incident linearly polarized light.
And the focal length of the liquid crystal lens 2 becomes shorter. On the other hand, as shown in FIG. 19, when the switch 6 is turned on and an electric field is applied to the liquid crystal layer 5, the long axis of the liquid crystal molecules 5a is parallel to the optical axis. The refractive index decreases, and the focal length of the liquid crystal lens 2 increases. As described above, in the optical system shown in FIG. 18, the focal length is made variable by selectively applying an electric field to the liquid crystal lens 2.

[0005]

However, FIG.
In the optical system using the liquid crystal lens 2 shown in (1), it is necessary to dispose the polarizing plate 1 in front of the liquid crystal lens 2 so that only a predetermined linearly polarized light component is incident on the liquid crystal lens 2. There is a problem that the amount of light passing through 1 and entering the liquid crystal lens 2 decreases, and the light use efficiency decreases.
In addition, since the light use efficiency is low as described above, there is a problem that applicable products are limited and lack versatility.

The present invention has been made in view of the above-mentioned conventional problems, and can improve the light use efficiency, and has excellent versatility appropriately configured so that it can be effectively applied to various optical products. It is another object of the present invention to provide a variable focus lens, a variable focus diffractive optical element, and a variable deflection prism as liquid crystal optical elements.

[0007]

To achieve the above object, a variable focus lens according to the present invention has, for example, the following configuration. A first optical member having first and second surfaces and transmitting incident light through the first and second surfaces; and a third surface receiving light transmitted through the first optical member. A second optical member, a lens surface formed on at least one of the first, second, and third surfaces; a pair of transparent electrodes provided on the second and third surfaces, respectively; A polymer-dispersed liquid crystal layer provided between electrodes, and a light transmitted through the first and second optical members by applying an electric field to the polymer-dispersed liquid crystal layer through the pair of transparent electrodes. Alternatively, the focus position of light transmitted through the first optical member, reflected by the third surface, and transmitted through the first optical member can be changed again. .

Further, the variable focus diffractive optical element according to the present invention has, for example, the following configuration. First and second
A first optical member that transmits incident light through the first and second surfaces, and a third optical member that has third and fourth surfaces, and transmits light transmitted through the first optical member. A second optical member that emits light through the third and fourth surfaces, a diffraction surface formed on at least one of the first, second, and third surfaces, and a second optical member on the second and third surfaces. A transparent electrode provided respectively, and a polymer-dispersed liquid crystal layer provided between the transparent electrodes, and by applying an electric field to the polymer-dispersed liquid crystal layer through the pair of transparent electrodes, The present invention is characterized in that the focal position of light transmitted through the second optical member can be changed.

Further, the variable deflection prism according to the present invention has, for example, the following configuration. A first optical member having first and second surfaces and transmitting incident light through the first and second surfaces; and a first optical member having third and fourth surfaces. A second optical member for emitting light transmitted through the third and fourth surfaces, and the first and second optical members.
And an inclined surface formed on at least one of the third surfaces;
A transparent electrode provided on each of the second and third surfaces; and a polymer dispersed liquid crystal layer provided between the transparent electrodes. An electric field is applied to the polymer dispersed liquid crystal layer through the pair of transparent electrodes. Is applied to change the deflection angle of light transmitted through the first and second optical members.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing a principle configuration of a variable focus lens according to the present invention. The varifocal lens 11 has lens surfaces 8a and 8b as first and second surfaces.
A first lens 12a having lens surfaces, a second lens 12b having lens surfaces 9a and 9b as third and fourth surfaces,
A polymer-dispersed liquid crystal layer 14 provided between the lenses via transparent electrodes 13a and 13b, and allows incident light to pass through first and second
Are converged through the lenses 12a and 12b.
The transparent electrodes 13a and 13b are connected to an AC power supply 16 via a switch 15 to selectively apply an AC electric field to the polymer dispersed liquid crystal layer 14. The polymer-dispersed liquid crystal layer 14 includes a large number of microscopic polymer cells 18 each having an arbitrary shape such as a sphere or a polyhedron containing liquid crystal molecules 17. To the sum of the volumes occupied by the polymer and the liquid crystal molecules 17, respectively.

Here, when the size of the polymer cell 18 is, for example, spherical, the average diameter D is 2 nm ≦ D ≦ λ / 5 (1 ). That is, since the size of the liquid crystal molecules 17 is about 2 nm or more, the lower limit of the average diameter D is set to 2 nm or more. The upper limit of D also depends on the thickness t of the polymer dispersed liquid crystal layer 14 in the optical axis direction of the varifocal lens 11, but if it is larger than λ, the refractive index of the polymer and the Due to the difference from the refractive index, light is scattered at the boundary surface of the polymer cell 18 and the polymer dispersed liquid crystal layer 14 becomes opaque, so that it is preferably λ / 5 or less as described later. High precision may not be required depending on the optical product in which the varifocal lens is used, and D may be λ or less. The transparency of the polymer-dispersed liquid crystal layer 14 becomes worse as the thickness t increases.

As the liquid crystal molecules 17, for example, uniaxial nematic liquid crystal molecules are used. Refractive index ellipsoid of the liquid crystal molecules 17 becomes the shape as shown in FIG. 2, an _{n ox = n oy = n o} (2). However, n _o is the refractive index of an ordinary ray, n _ox and n _oy are refractive indices in directions perpendicular to each other in a plane including an ordinary ray.

Here, as shown in FIG.
Is turned off, that is, in a state where an electric field is not applied to the polymer dispersed liquid crystal layer 14, the liquid crystal molecules 17 are oriented in various directions, so that the refractive index of the polymer dispersed liquid crystal layer 14 for incident light is high and the refractive power is strong. It becomes a lens. On the other hand, as shown in FIG. 3, when the switch 15 is turned on and an AC electric field is applied to the polymer-dispersed liquid crystal layer 14, the long axis direction of the refractive index ellipsoid changes the optical axis of the varifocal lens 11. Since the lens is oriented so as to be parallel to the lens, the lens has a low refractive index and has a low refractive power.

The voltage applied to the polymer-dispersed liquid crystal layer 14 can be changed stepwise or continuously by a variable resistor 19 as shown in FIG. In this way, as the applied voltage increases, the liquid crystal molecules 17 are oriented so that the major axis of the ellipse gradually becomes parallel to the optical axis of the varifocal lens 11, so that the refractive power is increased stepwise or continuously. Can be changed to

Here, the average refractive index n _LC ′ of the liquid crystal molecules 17 in the state shown in FIG. 1, that is, without applying an electric field to the polymer-dispersed liquid crystal layer 14, is shown in FIG. When the refractive index of the long axis and n _z, is approximately _{(n ox + n oy + n} z) / 3≡n LC '(3). Moreover, average refractive index n _LC when equation (2) is satisfied, it represents a n _z the refractive index n _e of the extraordinary ray is given by _{(2n o + n e) /} 3≡n LC (4). At this time, the refractive index n _A of the polymer-dispersed liquid crystal layer 14 is represented by the ratio of the volume of the liquid crystal molecules 17 to the volume of the polymer-dispersed liquid crystal layer 14, where n _P is the refractive index of the polymer constituting the polymer cell 18. Is given by ff, and according to Maxwell Garnet's law, n _A = ff · n _LC ′ + (1−ff) n _P (5)

Therefore, as shown in FIG.
Assuming that the radii of curvature of the inner surfaces of 2a and 12b, that is, the surfaces on the polymer dispersed liquid crystal layer 14 side are R ₁ and R ₂ , respectively, the focal length f ₁ of the varifocal lens 11 is 1 / f ₁ = (n _A -1) (1 / R ₁ -1 / R ₂ ) (6) Note that R ₁ and R ₂ are positive when the center of curvature is on the image point side. Also, refraction by the outer surfaces of the lenses 12a and 12b is excluded. That is, the focal length of the lens by only the polymer dispersed liquid crystal layer 14 is
It is given by equation (6).

Further, the average refractive index of the ordinary ray, if _{(n ox + n oy) /} 2 = n o ' and (7) was applied state shown in FIG. 3, i.e. the electric field to the liquid crystal layer 14 Polymer dispersed liquid crystal layer 14 in the state
The refractive index n _B, because it is given by _{n B = ff · n o '} + (1-ff) n P (8), the focal length f ₂ of the liquid crystal layer 14 lens according to only this case, 1 / f ₂ = (n _B −1) (1 / R ₁ −1 / R ₂ ) (9) The focal length when a voltage lower than that in FIG. 3 is applied to the polymer dispersed liquid crystal layer 14 is as follows:
It is a value between the focal length f ₁ given by the equation (6) and the focal length f ₂ given by the equation (9).

From the above equations (6) and (9), the rate of change of the focal length by the polymer-dispersed liquid crystal layer 14 is | (f ₂ −f ₁ ) / f ₂ | = | (n _B −n _A ) / (N _B −1) | (10) Therefore, to increase the rate of change, it is only necessary to increase | n _B −n _A |. Here, since it is _{n B -n A = ff (n} o '-n LC') (11), | n o '-n LC' | if the large, it is possible to increase the change rate. Practically, n _B is
Because it is about _{1.3~2, 0.01 ≦ | n o '} -n LC' | if ≦ 10 (12), when ff = 0.5, the focal length obtained by the liquid crystal layer 14 , 0.5% or more, an effective variable focus lens can be obtained. It should be noted _{that, | n o '-n LC'} | because of restrictions on liquid crystal substances, 10
Cannot be exceeded.

Next, the grounds for the upper limit of the above equation (1) will be described. `` Solar Energy Materials and Solar Cel
ls '', Vol. 31, Wilson and Eck, 1993, Eleevier Science Pub
lishers Bv pages 197-214, `` Transmission v
ariation using scattering / transparent switching fi
“lms” shows the change in the transmittance τ when the size of the polymer-dispersed liquid crystal is changed. On page 206 of this document, FIG. 6 shows that the radius of the polymer dispersed liquid crystal is r, t = 300 μm, ff = 0.5, n _P = 1.45, n
_{When LC} = 1.585 and λ = 500 nm, the transmittance τ
Is a theoretical value, r = 5 nm (D = λ / 50, D · t = λ
Τ ≒ 90% at 6 μm (where D and λ are in nm and the same applies hereinafter), and r = 25 nm (D = λ
/ 10), it is shown that τ ≒ 50%.

Here, for example, when estimating the case where t = 150 μm, assuming that the transmittance τ changes as an exponential function of t, the transmittance τ when t = 150 μm is estimated. , R = 25 nm (D = λ / 10, D · t = λ · 1)
5 μm), τμ71%. Also, t = 75 μm
, Similarly, r = 25 nm (D = λ / 10, D ·
τ ≒ 80% when t = λ · 7.5 μm).

From these results, if D · t ≦ λ · 15 μm (13), τ is 70% to 80% or more, and the lens is sufficiently practical. Therefore, for example, t = 75 μm
In the case of, a sufficient transmittance can be obtained when D ≦ λ / 5.

The transmittance of the polymer dispersed liquid crystal layer 14 is as follows:
The better the value of n _P is closer to the value of n _LC ′, the better. on the other hand,
If n _o 'and n _P have different values, the transmittance of the polymer-dispersed liquid crystal layer 14 will be poor. In the state of the state and 3 of FIG. 1, average of the transmittance of the liquid crystal layer 14 is improved by _{the, n P = (n o '} + n LC') / 2 (14) when satisfying It is.

Here, since the varifocal lens 11 is used as a lens, it is preferable that the transmittance is substantially the same and high in both the state shown in FIG. 1 and the state shown in FIG. For this purpose, there is a limit to the material of the polymeric material and the liquid crystal molecules 17 constituting the polymer cell 18, the _{practical, n o '≦ n P ≦} n LC' (15) and may be.

If the above equation (14) is satisfied, the above equation (1) is satisfied.
The expression (3) is further relaxed, and it suffices that D · t ≦ λ · 60 μm (16). Because, according to Fresnel's law of reflection, the reflectance is proportional to the square of the difference in refractive index, so that light is reflected at the boundary between the polymer constituting the polymer cell 18 and the liquid crystal molecules 17, ie, the polymer dispersion. This is because the decrease in the transmittance of the liquid crystal layer 14 is approximately proportional to the square of the difference in the refractive index between the polymer and the liquid crystal molecules 17.

[0025] The _{above, n o '≒ 1.45, n} LC' ≒ 1.
585 was the case, more generally formulated, may be a D · t ≦ λ · 15μm · (1.585 -1.45) 2 / (n u -n P) 2 (17). However, (n _u -n _P ) ² is (n _LC ′
−n _P ) ² and ( _no′− n _P ) ² , whichever is larger.

The change in the focal length of the varifocal lens 11
In order to increase the value of ff, it is better that the value of ff is large, but ff = 1
Then, the volume of the polymer becomes zero and the polymer cell 18 is formed.
0.1 ≦ ff ≦ 0.999 (18) On the other hand, since τ increases as ff decreases,
The expression (17) is preferably 4 × 10^-6[Μm]^Two≦ D ・ t ≦ λ ・ 45μm ・ (1.585-1.45)^Two/ (n_u-N_P) ^Two (19) Note that the lower limit of t is apparent from FIG.
In addition, when t = D, D is 2 nm or more as described above.
Therefore, the lower limit of D · t is (2 × 10^-3μm)^Two,sand
4 × 10^-6[Μm]^TwoBecomes

It should be noted that the approximation of expressing the optical property of a substance by a refractive index is established as described in “Iwanami Science Library 8: Asteroid Comes” by Tadashi Mukai, 1994, p. 58, published by Iwanami Shoten. , D is larger than 10 nm to 5 nm. When D exceeds 500λ, light scattering becomes geometrical, and light scattering at the interface between the polymer constituting the polymer cell 18 and the liquid crystal molecules 17 increases according to the Fresnel reflection formula. Is practically 7 nm ≦ D ≦ 500λ (20).

[0028] In the configuration shown in FIG. 1 or FIG. 4, the above _{n ox, n oy, n o} , n z, n e, n P, ff, D, t,
λ, R ₁ , R ₂ , n _LC ′, n _LC , n _A , n _B , f ₁ , f
₂ and the diameter φ of the varifocal lens 11 are specifically set to the following values, respectively. _{n ox = n oy = n o} = 1.5 n z = n e = 1.75 n P = 1.54 ff = 0.5 D = 50nm t = 125μm λ = 500nm R 1 = 25mm R 2 = ∞ n _{LC '= n LC = 1.5833 n} A = 1.5617 n B = 1.52 f 1 = 44.5mm f 2 = 48.04mm φ = 5mm

[0029] In this case, the right side of the expression (19), λ · 45μm · (1.585-1.45) 2 / (n u -n P) 2 = 500
nm ・ 45μm ・ (0.135) ² /(0.0433) ² ≒ 218712nm
・ Μm D · t = 50 nm · 125 μm = 6250 nm · μm, which certainly satisfies the expression (19).

In the above specific example, R ₁ = R ₂
= ∞. In this case, since the optical path length of the polymer-dispersed liquid crystal layer 14 changes depending on the on / off of the voltage, the focus adjustment is performed by disposing the varifocal lens 11 at a portion where the light flux of the lens system is not parallel. Or to change the focal length or the like of the entire lens system.

FIG. 5 shows the configuration of an image pickup optical system for a digital camera using the varifocal lens 11 shown in FIG. In this imaging optical system, an object (not shown)
The image of the diaphragm 21, the varifocal lens 11 and the lens 2
An image is formed on the solid-state imaging device 23 composed of, for example, a CCD via the imaging device 2. In FIG. 5, illustration of liquid crystal molecules is omitted.

According to the imaging optical system, the variable resistor 1
9 to adjust the AC voltage applied to the polymer dispersed liquid crystal layer 14 of the varifocal lens 11 to change the focal length of the varifocal lens 11, thereby moving the varifocal lens 11 and the lens 22 in the optical axis direction. For example, it is possible to continuously focus on an object distance from infinity to 600 mm.

FIG. 6 shows the configuration of an objective optical system for an electronic endoscope using the variable focus lens according to the present invention. In this objective optical system, an image of an object (not shown) is formed on a solid-state imaging device 29 formed of, for example, a CCD via a front lens 25, an aperture 26, a variable focus lens 27, and a rear lens 28. Here, the varifocal lens 27
Makes the radius of curvature R1 of the inner surface of one lens 12a sandwiching the polymer-dispersed liquid crystal layer 14 infinite and the other lens 12b
Is formed in the same manner as in FIG. 4 except that the inner surface of the
, Through the variable resistor 19 and the switch 15 to apply an AC voltage. In FIG. 6, illustration of liquid crystal molecules is omitted.

In such an objective optical system as well, the AC voltage applied to the polymer dispersed liquid crystal layer 14 of the varifocal lens 27 is adjusted according to the object distance, and the focal length of the varifocal lens 27 is changed, so that Focus adjustment can be performed without moving the focusing lens 27 and the rear lens 28 in the optical axis direction.

FIG. 7 shows an example of the configuration of a variable focus diffractive optical element according to the present invention. The variable-focus diffractive optical element 31 has parallel first and second surfaces 32a and 32b.
And a second transparent substrate having a third surface 33a and a flat fourth surface 33b on which a ring-shaped diffraction grating having a sawtooth-shaped cross section having a groove depth on the order of the wavelength of light is formed. And a substrate 33 for emitting incident light through the first and second transparent substrates 32 and 33. First
The polymer dispersed liquid crystal layer 14 is provided between the second transparent substrates 32 and 33 via the transparent electrodes 13a and 13b as described with reference to FIG.
Is connected to an AC power supply 16 through the
An AC electric field is applied to the.

In this configuration, the light beam incident on the variable focus diffractive optical element 31 is deflected by an angle θ satisfying p sin θ = mλ (21), where p is the grating pitch of the third surface 33a and m is an integer. And emitted. Further, assuming that the groove depth is h, the refractive index of the transparent substrate 33 is n _33, and k is an integer, h (n _A −n ₃₃ ) = mλ (22) h (n _B −n ₃₃ ) = kλ (23) ), The diffraction efficiency becomes 100% at the wavelength λ, and the occurrence of flare can be prevented.

Here, when the difference between both sides of the above equations (22) and (23) is obtained, h (n _A −n _B ) = (m−k) λ (24) is obtained. Therefore, for example, λ = 500 nm, n
_A = 1.55, when _{n B = 1.5, 0.05h = (} m-k) · 500nm next, when m = 1, k = 0, the h = 10000nm = 10μm. In this case, the refractive index n ₃₃ of the transparent substrate 33, the above equation (22) may be any n ₃₃ = 1.5. Further, the grating pitch p in the peripheral portion of the variable focus diffractive optical element 31
Is set to 10 μm, θ ≒ 2.87 °, and a lens having an F-number of 10 can be obtained.

Since the optical path length of the variable focus diffractive optical element 31 changes depending on the on / off of the voltage applied to the polymer dispersed liquid crystal layer 14, for example, the variable focus diffractive optical element 31 is disposed in a portion where the light flux of the lens system is not parallel to focus. It can be used to make adjustments or to change the focal length or the like of the entire lens system.

In this embodiment, (2)
2) - (24) equation, _{practically, 0.7mλ ≦ h (n A -n} 33) ≦ 1.4mλ (25) 0.7kλ ≦ h (n B -n 33) ≦ 1.4kλ (26) 0.7 (m-k) λ ≦ h (n a -n B) ≦ 1.4 (m-k) λ (27) may satisfy the.

FIGS. 8 and 9 show variable-focus spectacles 35 using a variable-focus diffractive optical element 36 as a spectacle lens. The variable focus diffractive optical element 36 is a lens 3
7 and 38, and a ring-shaped diffraction grating having a sawtooth cross section similar to that described with reference to FIG. 7 is formed on the inner surface of the lens 37 on the incident side. On the inner surfaces of these lenses 37 and 38, the alignment film 3 is provided via transparent electrodes 13a and 13b, respectively.
9a and 39b are provided, and a polymer dispersed liquid crystal layer 14 similar to that described with reference to FIG. 1 is provided between these alignment films 39a and 39b. The transparent electrodes 13a and 13b are connected to the switch 15
To the AC power supply 16, thereby applying an AC electric field to the polymer dispersed liquid crystal layer 14.

According to the varifocal glasses 35 having such a configuration,
When the switch 15 shown in FIG. 8 is turned off by, for example, manually turning on / off the switch 15,
Since the arrangement of the liquid crystal molecules 17 in the polymer dispersed liquid crystal layer 14 can be changed when the switch 15 is turned on, the diopter of the entire spectacle lens can be changed. Therefore, the sense of incongruity is reduced as compared with a case in which the diopter changes in the direction of the line of sight, such as the glasses 42 using the conventional bifocal lens 41 shown in FIG.

FIG. 11 shows a variable focus spectacles 35 shown in FIG. 8, in which a frame 35a is provided with a distance measuring sensor 46 for measuring the distance to the object 45, and the switch 15 is turned on based on the output of the distance measuring sensor 46. -The diopter is automatically adjusted by controlling the off state.

As described above, if the diopter is automatically adjusted based on the object distance, it is possible to obtain eyeglasses that are particularly useful for an elderly man with a diminished diopter adjusting ability.

In the variable focus spectacles 35 shown in FIGS. 8 and 11, the entire spectacle lens is the variable focus diffractive optical element 36, but a part of the spectacle lens, for example, FIG.
As shown in (5), the variable focus diffractive optical element 36 may be provided slightly below the center. Further, the variable focus lens 1 shown in FIG.
1 or the varifocal lens 27 shown in FIG. 6 can also be used. Further, in FIG. 11, the switch 15 is automatically switched based on the output of the distance measuring sensor 46. However, a new switch can be provided to select between automatic switching by the distance measuring sensor 46 and manual switching. Alternatively, it may be configured such that the automatic switching by the distance measuring sensor 46 can be changed to manual switching. Furthermore, a hearing aid may be provided integrally with the variable-focus glasses 35 described above.

Further, as shown in FIG.
Is provided, the voltage applied to the polymer dispersed liquid crystal layer 14 of the variable focus diffractive optical element 36 can be varied stepwise or continuously, and the output of the distance measuring sensor 46 and the applied voltage can be changed according to the user. Preset the correspondence with
The applied voltage may be controlled based on the output of the distance measuring sensor 46. In this way, more accurate diopter adjustment according to the object distance can be automatically performed for each user.

Further, in the varifocal glasses 35 described above, the AC power supply 16 can be constituted by an inverter circuit using a battery as a power supply. In this case, as the battery, one or more of a manganese battery, a lithium battery, a solar battery, and a rechargeable battery are integrated with the frame 35a,
That is, it may be built in, provided separately and connected by a cord, or have a built-in battery and an external battery.

In the case of simply constructing variable-focus glasses, a variable-focus lens using twisted nematic liquid crystal may be used instead of the above-described variable-focus lens using polymer-dispersed liquid crystal. FIG. 13 and FIG.
It shows the configuration of the variable focus glasses 50 in this case,
The varifocal lens 51 includes lenses 52 and 53, alignment films 39a and 39b provided on the inner surfaces of the lenses via transparent electrodes 13a and 13b, respectively, and a twisted nematic liquid crystal layer 54 provided between the alignment films. The transparent electrodes 13a and 13b are connected to an AC power supply 16 via a variable resistor 19 to apply an AC electric field to the twisted nematic liquid crystal layer 54.

In this configuration, when the voltage applied to the twisted nematic liquid crystal layer 54 is increased, the liquid crystal molecules 5
5 has a homeotropic alignment as shown in FIG. 14, and the twisted nematic liquid crystal layer 54 has a smaller voltage than the twisted nematic state shown in FIG.
Has a smaller refractive index and a longer focal length.

Here, since the helical pitch P of the liquid crystal molecules 55 in the twisted nematic state shown in FIG. 13 needs to be sufficiently smaller than the wavelength λ of light, for example, 2 nm ≦ P ≦ 2λ / 3 (28) And Note that the lower limit of this condition is determined by the size of the liquid crystal molecules, and the upper limit is determined when the incident light is natural light, as shown in FIG.
This is a value necessary for the twisted nematic liquid crystal layer 54 to behave as an isotropic medium in the state described above. If the condition of the upper limit is not satisfied, the varifocal lens 51 becomes a lens having a different focal length depending on the polarization direction. A superimposed image is formed and only a blurred image can be obtained.

FIG. 15A shows the configuration of a variable deflection prism according to the present invention. The variable deflection prism 61 includes an incident-side first transparent substrate 62 having first and second surfaces 62a and 62b, and third and fourth surfaces 63a and 63.
Outgoing side parallel flat second transparent substrate 63 having 3b
And Inner surface (second surface) of incident side transparent substrate 62
62b is formed in a Fresnel shape, and the polymer dispersed liquid crystal layer 14 is provided between the transparent substrate 62 and the transparent substrate 63 on the emission side via the transparent electrodes 13a and 13b as described with reference to FIG. . The transparent electrodes 13a and 13b are connected to an AC power supply 16 via a variable resistor 19, thereby applying an AC electric field to the polymer-dispersed liquid crystal layer 14 to control the deflection of light transmitted through the variable deflection prism 61. To do it. In addition,
In FIG. 15 (A), the inner surface 62b of the transparent substrate 62 is formed in a Fresnel shape. For example, as shown in FIG. 15 (B), the inclined surfaces where the inner surfaces of the transparent substrates 62 and 63 are relatively inclined are formed. It can be formed in the shape of a normal prism having the same, or can be formed in the shape of a diffraction grating shown in FIG. In the case of forming a diffraction grating, the above equations (21) to (27) similarly apply.

The variable deflection prism 61 having the above-described configuration is, for example, a TV camera, a digital camera, a film camera,
It can be effectively used for blur prevention of binoculars and the like. In this case, it is desirable that the refraction direction (deflection direction) of the variable deflection prism 61 is in the vertical direction, but in order to further improve the performance, the deflection directions of the two variable deflection prisms 61 are made different. For example, as shown in FIG. 16, it is desirable to arrange so as to change the refraction angle in the directions perpendicular to the vertical and horizontal directions. In FIGS. 15 and 16,
Illustration of liquid crystal molecules is omitted.

FIG. 17 shows a variable focus mirror as a variable focus lens according to the present invention. The variable focus mirror 65 includes a first transparent substrate 66 having first and second surfaces 66a and 66b, and third and fourth surfaces 67a and 67.
b, and a second transparent substrate 67 having b. The first transparent substrate 66 is formed in the shape of a flat plate or a lens, and a transparent electrode 13a is provided on an inner surface (second surface) 66b. The second transparent substrate 67 has an inner surface (third surface) 67a. The reflective film 68 is formed on the concave surface, and the transparent electrode 13b is provided on the reflective film 68. Transparent electrode 13a, 1
3b, a polymer-dispersed liquid crystal layer 14 is provided as described with reference to FIG. 1, and these transparent electrodes 13a and 13b are connected to an AC power supply 16 via a switch 15 and a variable resistor 19. An AC electric field is applied to the liquid crystal layer 14. In FIG. 17, the liquid crystal molecules are not shown.

According to such a configuration, the light incident from the transparent substrate 66 side is reflected by the reflective film 68 to the polymer dispersed liquid crystal layer 1.
4 is an optical path that is folded back, so that the action of the polymer dispersed liquid crystal layer 14 can be provided twice, and the focal position of the reflected light can be changed by changing the voltage applied to the polymer dispersed liquid crystal layer 14. . In this case, the light beam incident on the varifocal mirror 65 passes through the polymer dispersed liquid crystal layer 14 twice, so that twice the thickness of the polymer dispersed liquid crystal layer 14 is t.
Then, the above equations can be similarly used. Note that the inner surface of the transparent substrate 66 or 67 may be formed in a diffraction grating shape as shown in FIG. 7 to reduce the thickness of the polymer-dispersed liquid crystal layer 14. This has the advantage that scattered light can be reduced.

In the above description, in order to prevent the deterioration of the liquid crystal, the AC power supply 16 is used as a power supply to apply an AC electric field to the liquid crystal. However, a DC power supply is used to apply the DC electric field to the liquid crystal. It can also be done. Also,
As a method of changing the direction of the liquid crystal molecules, in addition to changing the voltage, the frequency of the electric field applied to the liquid crystal, the strength and frequency of the magnetic field applied to the liquid crystal, or the temperature of the liquid crystal may be changed. In the embodiment described above, the polymer-dispersed liquid crystal is not liquid but may be almost solid. In that case, one of the lenses 12a and 12b, one of the transparent substrate 32, the lens 38, and one of the lenses 52 and 53, and FIG.
The transparent substrate 63 in FIG. 5A, one of the transparent substrates 62 and 63 in FIG. 15B, and one of the transparent substrates 66 and 67 may not be provided.

Next, a method of manufacturing a lens of an inhomogeneous medium, which is one of the lenses, will be described. An inhomogeneous medium lens is a lens made of a medium having a different refractive index for each lens portion. For example, in the case of a radial gradient inhomogeneous medium lens 71 whose refractive index changes in the radial direction as shown in FIG. As shown in FIG. 21, the refractive index n decreases as the radius r increases with respect to the optical axis O which is the spectral central axis (refractive index distribution central axis). The refractive index does not change in the direction along the optical axis.

The material of such an inhomogeneous medium lens 71 is made of a material such as glass or plastic by an ion exchange method or a sol-gel method. However, as shown in FIG. 22, the material 72 of the heterogeneous medium lens produced by these methods is rod-shaped, so that in order to obtain the heterogeneous medium lens 71 as a final product, cutting, polishing, coating, etc. It is necessary to go through the process of.

On the other hand, when obtaining a normal homogeneous lens made of glass or the like, first, both sides of one lens are polished,
Next, the outer periphery is cut so as to be rotated with respect to a line (optical axis) connecting the centers of the two spherical surfaces. This method is widely used in general, and has the advantage of being inexpensive.

However, in the case of an inhomogeneous medium lens, unlike ordinary lens processing, the spectral center axis of the material 72 must be located at the center of the outer periphery of the lens.
As shown in (1), the lens surface 73 must be perpendicular to the spectral center axis. For this reason, when manufactured by the above-described normal lens processing method, the center of the spectral center and the center of the outer periphery of the lens may be shifted or tilted, and the lens surface 73 may not be orthogonal to the spectral center axis exactly. .

Hereinafter, a method for manufacturing a heterogeneous medium lens that can solve such a problem will be described with reference to the drawings. First, an example of a manufacturing method when the lens surface 73 is flat will be described. In this case, it is assumed that the spectral center axis is located at the center of the material 72. This assumption actually agrees with the material 72 made by the ion exchange method, the sol-gel method, or the like. First, as shown in FIG. 23, the diameter of the material 72 is reduced with a centerless 75 so that the spectral center axis does not deviate from the center of the material 72. In addition, centerless 75
The distance between the two axes is adjusted in advance so that the outer diameter of the material 72a that has been cut and reduced becomes the required lens diameter.

Next, as shown in FIG. 24, the raw material 72a is cut by a cutting machine 76 into a required lens length with an allowance for polishing. Thereafter, as shown in FIG. 25, the cut material 72b is adhered to the side surface of the V groove of the V block 77 placed on the plane so that the spectral central axis is orthogonal to the plane, or As shown at 26, the gear 78 is bonded to the side face of the tooth groove so that the central axis of the gear 78 and the spectral central axis are parallel.

Next, the material 72b adhered to the V block 77 or the gear 78 is set on a surface grinding machine 81 as shown in FIG. 27, and one lens surface of the material 72b is set to be orthogonal to the spectral center axis. With a diamond whetstone. Then, as shown in FIG. 28, the polishing machine 82 gradually performs fine grinding in several stages using fine diamond pellets 82a, and then grinds with CeO ₂ and water using a urethane sheet or a pitch. To make the lens surface mirror-finished. The other lens surface is also mirror-finished by performing the steps shown in FIGS.

Thereafter, as shown in FIG.
After chamfering both lens surfaces with 4 or the like, a multi-coat for anti-reflection or a single-layer coat such as MgF ₂ is applied to both lens surfaces to obtain an inhomogeneous medium lens having two flat surfaces.

When the perpendicularity of the cut surface (lens surface) with respect to the spectral center axis is maintained in the cutting step shown in FIG. 24, the V block 77 shown in FIG. 25 or FIG.
Alternatively, the fine grinding and polishing of the lens surface shown in FIGS. 27 and 28 may be performed without bonding to the gear 78. When the polishing of one lens surface is completed in the step shown in FIG. 28, the polished lens surface is abutted against an attaching plate 86 as shown in FIG. Fine grinding and polishing may be performed. This simplifies the process and is advantageous in cost.

Further, in another manufacturing method when the lens surface 73 is a flat surface, the cutting step shown in FIG. 24 is performed without performing the outer diameter grinding step shown in FIG. The process shown in FIG. 28 is performed on both lens surfaces. Next, as shown in FIG. 31, the raw material 72c having been subjected to the polishing of the lens surface is attached to a cider type centering machine 90 via a pitch 88. When attaching this,
This is performed while checking the material 72c with the pick tester 91 or observing the outer periphery of the material 72c with the microscope 92 so that the material 72c does not shake when the cider type centering machine 90 is rotated. In this state, the outer periphery of the material 72c is ground with the grindstone 93 until the outer diameter of the finished lens is reached while rotating the cider type centering machine 90. Then, the cider centering machine 9
After chamfering at 0, an antireflection coating is applied to the lens surface to obtain an inhomogeneous medium lens whose lens center coincides with the spectral center axis.

While the method for manufacturing a heterogeneous medium lens having flat surfaces on both sides has been described above, the above-described manufacturing method is also effective in the case of a heterogeneous medium lens having a flat surface on one side, and when the outer diameter is uniform after finishing. Can be applied.

Next, an example of a manufacturing method for obtaining an inhomogeneous medium lens having a spherical surface with a radius R will be described. As shown in FIG. 32, first, a lens surface member 95 having a surface with a radius R is made of glass, metal, resin, or the like.
Thereafter, this lens surface member 95 is attached to the rotation axis of the cider type centering machine so as not to be eccentric, and while the rotation axis is being rotated, a non-uniform medium lens cut using a diamond grindstone 96 at the center thereof. A hole for accommodating the material is formed, and the outer periphery is centered. The lens surface member having this hole will be called a stop.

Next, as shown in FIG. 33, the cut inhomogeneous medium lens material 72d is put into the hole of the toy 97 and fixed with plaster or the like. In this state, as shown in FIG. Then, the material 72d is finely ground and polished together with the toy 97 to form a spherical surface having no eccentricity with respect to the spectral center axis. The cut non-homogeneous medium lens material 72c to be inserted into the hole of the yoke 97 can be cut in advance to the finished lens outer diameter without a center. In this case, as a matter of course, the hole of the stopper 97 has an inner diameter substantially equal to the outer diameter of the finished lens.

The other surface can be formed into a spherical surface in the same manner. In particular, when the edge of the lens (the dimension of the outer peripheral surface in the optical axis direction) is small, the other surface is formed by the following method. Can be formed into a spherical surface. That is, FIG.
As shown in FIG. 7, an inhomogeneous medium lens material 72e, one surface of which is polished to a spherical surface, is attached via a pitch 88 to a jaw 101 having a concave surface with a radius R on the spherical surface side. In this pasting, as described with reference to FIG. 31, while rotating the jaw 101, the material 72 e is checked by a pick tester 91 or the microscope 92 while observing the outer periphery of the material 72 e so that the material 72 e does not shake. Do. here,
The toy 101 has substantially the same diameter as a rotation axis of a curve generator or a centering machine described later, and can be attached to the curve generator or the centering machine with the material 72e adhered thereto. Note that it is preferable that the spherical surface to be attached to the toy 101 be a spherical surface having a large radius of curvature among the two spherical surfaces to be finally formed, in that the above-described attaching operation is easily performed.

Next, as shown in FIG.
Is attached to the curve generator 102, and the material 72e
Is ground so as to have a desired curvature. Thereafter, the jaws 101 are attached to a centering machine, and the outer periphery of the material 72e is ground to the finished outer diameter of the lens. Next, the other surface of the raw material 72e is polished to a mirror surface by an ordinary polishing machine, and then the necessary coating is applied to both surfaces to obtain a heterogeneous medium lens having spherical surfaces on both surfaces.

The step of grinding the outer periphery of the raw material 72e by the centering machine may be performed after polishing the other surface. In this case, as shown in FIG. 37, the outer periphery of the raw material 72e can be ground using a bell clamp centering machine 103. Also, after polishing the other surface, the material 72e
In the case of grinding the outer periphery of the material 101, as shown in FIG.
And grind with a grindstone while rotating the toy 101. In this case, the material 72e is attached to the toy 101 while observing with the microscope 92 so as not to cause rotational shake. Alternatively, the spherical surface of the raw material 72e (FIG.
In 8, the outer periphery of the material 72 e can be ground by observing the shake of the reflection image on the right side surface).

The spherical inhomogeneous medium lens is not limited to the above-described manufacturing method. In particular, when the rim of the lens, that is, the dimension of the outer peripheral surface of the lens in the optical axis direction is large, it can be obtained by the following method. Can be. That is, as shown in FIG. 39, first, the cut material 72b is attached to a collet chuck 105, and one surface is ground to a desired spherical surface by a curve generator 102, and then the surface is finely ground and pitch-polished to obtain a mirror surface. To Next, as shown in FIG.
Collet chuck 1 having pipe 106 supporting spherical surface
At 07, the material 72b is attached so that the other surface (unpolished surface) of the material 72b is outside, and the other surface is similarly ground to a desired spherical surface by the curve generator 102. The reason why the pipe 106 is used is that the rim L of the lens is set to a desired value and that the material 72b is used.
This is to prevent the spherical surface from being decentered with respect to the spectral central axis of (1). Then, the other surface ground into a spherical surface is finely ground and pitch-polished to obtain a mirror surface. Next, if necessary, the outer diameter of the material 72b is ground to the finished lens outer diameter by any one of the methods described above, and then chamfering and coating are performed to obtain a heterogeneous medium lens having spherical surfaces on both sides. In the above description, a spherical inhomogeneous medium lens is manufactured. However, an aspherical inhomogeneous medium lens can be manufactured in the same manner.

Additional Items 1. The variable focus lens according to claim 1, wherein the variable focus lens has first and second surfaces, and a first optical member that transmits incident light through the first and second surfaces. A second optical member having a third surface for receiving light transmitted through the first optical member; a lens surface formed on at least one of the first, second, and third surfaces; And a polymer dispersed liquid crystal layer provided between the transparent electrodes, and an electric field is applied to the polymer dispersed liquid crystal layer via the pair of transparent electrodes. Thereby, the focal point of the light transmitted through the first and second optical members or the light transmitted through the first optical member, reflected by the third surface, and transmitted through the first optical member again. A varifocal lens characterized in that the position can be changed. 2. 3. The variable focus diffractive optical element according to claim 2, wherein the variable focus diffractive optical element has first and second surfaces,
A first for transmitting incident light through the first and second surfaces;
An optical member having a third and a fourth surface, and a second optical member that emits light transmitted through the first optical member through the third and the fourth surface; A diffractive surface formed on at least one of the second and third surfaces;
And a transparent electrode provided on the third surface side, and a polymer dispersed liquid crystal layer provided between the transparent electrodes, and an electric field is applied to the polymer dispersed liquid crystal layer via the pair of transparent electrodes. The variable focus diffractive optical element is characterized in that the focus position of the light passing through the first and second optical members can be changed. 3. 4. The variable deflection prism according to claim 3, wherein the variable deflection prism has first and second surfaces, and a first optical member that transmits incident light through the first and second surfaces. , A second optical member having a third surface and a fourth surface, and for emitting light transmitted through the first optical member through the third and fourth surfaces; and the first, second, and third surfaces. 3, a transparent electrode provided on each of the second and third surfaces, and a polymer-dispersed liquid crystal layer provided between the transparent electrodes. A variable declination characterized in that a declination of light transmitted through the first and second optical members can be varied by applying an electric field to the polymer-dispersed liquid crystal layer through a transparent electrode. prism. 4. Variable-focus glasses comprising the variable-focus lens or variable-focus diffractive optical element according to claim 1. 5. 4. An optical deflecting device, comprising a plurality of variable deflection prisms according to claim 3 or 3 arranged so as to have different deflection directions. 6. An imaging apparatus comprising the variable focus lens, the variable focus diffractive optical element, or the variable deflection prism according to any one of claims 1, 2, and 3. 7. 4. A liquid crystal optical element comprising a variable focus lens, a variable focus diffractive optical element or a variable deflection prism according to claim 1, 2, 3, or 3, wherein the polymer dispersed liquid crystal layer has A liquid crystal optical element characterized by satisfying 0.1 ≦ ff ≦ 0.999, where ff represents the ratio of the volume of liquid crystal molecules to the volume. 8. A liquid crystal optical element comprising a variable focus lens, a variable focus diffractive optical element or a variable deflection prism according to any one of claims 1, 2, and 3, and 4 × 10 ^-6 [μm ² ≦ D ・ t ≦ λ ・ 45μm ・ (1.585-1.
_{^{45) 2 / (n u -n}} P) liquid crystal optical element that satisfies the ^2. Here, D: average diameter of the polymer cell containing liquid crystal molecules constituting the polymer dispersed liquid crystal layer t: thickness of the polymer dispersed liquid crystal layer 14 in the optical axis direction λ: operating wavelength n _P : constituting the polymer cell refractive index of the polymer of ^{_{(n u -n P) 2:}} (n LC '-n P) 2 and (n _o' -n
_P) the larger of the ^2, n _LC ': average refractive index n _o of the liquid crystal molecules': average refractive index of ordinary ray 9. A liquid crystal optical element comprising a variable focus lens, a variable focus diffractive optical element, or a variable deflection prism according to any one of claims 1, 2, 3 and additional claims 1, 2 and 3, wherein 2 nm ≦ D ≦ λ / 5. A liquid crystal optical element characterized by satisfying the following. 9 '. 4. A liquid crystal optical element comprising a variable focus lens, a variable focus diffractive optical element, or a variable deflection prism according to claim 1, wherein 2 nm ≦ D <λ. A liquid crystal optical element. 10. Claim 1, 2, 3, the variable focus lens according to one of Additional Item 1, 2, 3, in the liquid crystal optical element consisting of a variable focal diffractive optical element or a variable deflection angle prism, 0.01 ≦ | n _o '-N _LC ' | ≤10. 11. 4. A liquid crystal optical element comprising a variable focus lens, a variable focus diffractive optical element, or a variable deflection prism according to claim 1, wherein 7 nm ≦ D ≦ 500λ. A liquid crystal optical element. 12. The variable-focus diffractive optical element according to any one of claims 2 and 7 to 11, wherein 0.7mλ ≦ h (n _A −n ₃₃ ) ≦ 1.4mλ 0.7kλ ≦ h (n _B − n ₃₃ ) ≦ 1.4 kλ 0.7 (mk) λ ≦ h (n _A −n _B ) ≦ 1.4 (m−
k) A variable focus diffractive optical element satisfying λ. Here, m and k: integers h: groove depth of the lattice n _A : refractive index of the polymer dispersed liquid crystal layer when no electric field is applied n _B : refractive index of the polymer dispersed liquid crystal layer when an electric field is applied n ₃₃ : refractive index of transparent substrate on which diffraction grating is formed Liquid crystal variable focus glasses comprising the variable focus lens or the variable focus diffractive optical element according to any one of claims 1 and 2, and additional claims 1, 2, 7 to 12. 14． 13. An imaging apparatus comprising the variable focus lens, the variable focus diffractive optical element, or the variable deflection prism according to any one of additional items 7 to 12. 15. It has a liquid crystal optical element as a spectacle lens having a pair of electrodes facing each other and a twisted nematic liquid crystal layer provided between these electrodes, and the twisted nematic liquid crystal layer has a helical pitch P of liquid crystal molecules in a twisted nematic state. Liquid crystal variable focus glasses satisfying 2 nm ≦ P ≦ 2λ / 3. 16. 3. The variable focus lens according to claim 1, wherein a reflective film is provided on the third surface so that an incident light beam is turned back into the polymer dispersed liquid crystal layer and passed a plurality of times. . 17． 17. A liquid crystal optical element comprising a variable focus lens, a variable focus diffractive optical element or a variable deflection prism according to any one of additional items 1 to 16, and a voltage source for applying a voltage between the pair of electrodes of the liquid crystal optical element. A liquid crystal optical device comprising: 18. 18. The liquid crystal optical device according to claim 17, wherein the voltage source is configured to apply a variable voltage between the pair of electrodes. 19. A method for manufacturing a heterogeneous medium lens, comprising manufacturing an inhomogeneous medium lens by grinding the outer diameter of the heterogeneous material to a finished lens diameter using a centerless lens. 20. In manufacturing a heterogeneous medium lens, the unevenness of the outer periphery of the heterogeneous material is adjusted using a pick tester or a microscope, and the heterogeneous material is fixed to a rotating shaft of a centering machine. A method for manufacturing a heterogeneous medium lens, comprising a step of grinding to a diameter. 21. In manufacturing an inhomogeneous medium lens, a curved surface of a desired shape is formed on the inhomogeneous material such that the center substantially coincides with the spectral center axis, and then the outer periphery of the inhomogeneous material is bell-clamped or cider-type centering machine. A method for producing a lens of a heterogeneous medium, comprising a step of grinding the lens to a finished outer diameter by using a method. 22. In manufacturing a heterogeneous medium lens, the method includes a step of grinding and polishing the heterogeneous material to a flat surface while fixing the heterogeneous material to a jig so as to be perpendicular to the grinding surface direction. A method for producing a heterogeneous medium lens. 23. 23. The method of manufacturing a heterogeneous medium lens according to claim 22, wherein a V-block or a gear is used as the jig. 24. In manufacturing a heterogeneous medium lens, a hole whose outer diameter is larger than the outer diameter of the heterogeneous medium lens to be manufactured, has a curved surface of a desired shape, and has a hole substantially equal to the diameter of the heterogeneous material in the center thereof. Using a formed toy made of glass, metal, resin, or the like, fixing a heterogeneous material in a hole of the toy, and grinding and polishing the heterogeneous material together with the toy to a curved surface of a desired shape. A method for producing a heterogeneous medium lens. 25. In manufacturing the heterogeneous medium lens, the curved surface of the heterogeneous material in which one surface is ground into a curved surface of a desired shape is used as a rotation axis of a yatoy having a curved surface of an opposite shape, and a pick tester or a microscope is used for the outer periphery. A method for manufacturing a heterogeneous medium lens, comprising a step of adjusting the run-out and fixing the same, and then grinding the other surface of the heterogeneous material into a curved surface having a desired shape using a curve generator. 26. In manufacturing a heterogeneous medium lens, after forming a curved surface of a desired shape whose center substantially coincides with the spectral central axis at both ends of the heterogeneous material, a step of centering the heterogeneous material by a bell clamp method is performed. A method for producing a lens of a heterogeneous medium, comprising: 27. In manufacturing an inhomogeneous medium lens, at each end of the inhomogeneous material, after forming a curved surface of a desired shape whose center substantially coincides with the spectral central axis, one of the curved surfaces has a curved surface of the opposite shape. A method for manufacturing a heterogeneous medium lens, comprising the steps of: fixing to a yatoi, observing a reflection image by the other curved surface, and centering the heterogeneous material with a cider-type centering machine. 28. In manufacturing a heterogeneous medium lens, after forming a curved surface of a desired shape whose center substantially coincides with the spectral central axis at both ends of the heterogeneous material, the heterogeneous material is centered by a cider-type centering machine. A method for producing a heterogeneous medium lens, comprising the steps of: 29. In manufacturing a heterogeneous medium lens, a step of grinding one surface into a curved surface of a desired shape using a curve generator while fixing the heterogeneous material with a collet chuck is provided. Manufacturing method of lens. 30. In manufacturing a heterogeneous medium lens, after forming one surface of the heterogeneous material into a curved surface of a desired shape having a center substantially coinciding with the spectral central axis, the heterogeneous material is colleted while supporting the curved surface with a pipe. A method for manufacturing an inhomogeneous medium lens, comprising a step of fixing with a chuck and grinding the other surface into a curved surface of a desired shape using a curve generator in this state. 31. In the method for manufacturing a heterogeneous medium lens according to any one of additional items 19 to 30, wherein the heterogeneous material is
A method for manufacturing a heterogeneous medium lens, characterized in that a material whose central axis and spectral central axis are substantially coincident is used.

According to the imaging device described in the above item 6, the response of the liquid crystal optical element is fast, so that the automatic focusing of a moving image can be performed. According to the method for manufacturing a heterogeneous medium lens described in Additional Item 19, a heterogeneous medium lens with little eccentricity can be obtained at low cost. According to the method of manufacturing a heterogeneous medium lens described in Additional Item 20, a more accurate heterogeneous medium lens can be obtained as compared with the manufacturing method described in Additional Item 19, and quality control can be easily performed. According to the method for manufacturing a heterogeneous medium lens described in Additional Item 21, by forming a curved surface having a desired shape with high precision, a heterogeneous medium lens with less eccentricity can be obtained by simple processing. According to the method for manufacturing a heterogeneous medium lens described in Additional Item 22, a heterogeneous medium lens having little plane eccentricity can be obtained. According to the method for manufacturing a heterogeneous medium lens described in Additional Item 24, a heterogeneous medium lens with less eccentricity can be easily obtained if even the yoke is accurately formed. Appendix 2
According to the method for manufacturing an inhomogeneous medium lens described in Item 5, even an inhomogeneous medium lens having a small edge can be easily obtained.
According to the method for manufacturing a heterogeneous medium lens described in Additional Item 26, a spherical lens having a small eccentricity can be obtained. According to the method for manufacturing a heterogeneous medium lens described in Additional Item 27, a highly accurate heterogeneous medium spherical lens with less eccentricity can be obtained. According to the method for manufacturing a heterogeneous medium lens described in Additional Item 28, a highly accurate non-uniform medium spherical lens with little eccentricity can be obtained by simple processing. According to the method for manufacturing a heterogeneous medium lens described in Additional Items 29 and 30, a spherical lens having a small amount of eccentricity can be easily obtained.

[0074]

According to the variable focus lens, the variable focus diffractive optical element and the variable deflection prism as the liquid crystal optical element according to the present invention, the polymer dispersed liquid crystal is used. Can be changed quickly to change its optical properties. Therefore, the optical path of the light beam passing through the liquid crystal optical element can be quickly changed. In addition, by using a polymer-dispersed liquid crystal, a polarizing plate is not necessarily required, so that a reduction in light amount can be suppressed. Therefore, a film camera, a microscope, a TV camera, binoculars, glasses, an endoscope, a digital camera, It can be widely used for focus adjustment of various optical devices such as pickups, zoom lenses, and blur prevention. Furthermore, in particular, the variable focus diffractive optical element and the variable deflection prism can be made thinner as a whole, so that light scattering can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a principle configuration of a variable focus lens according to the present invention.

FIG. 2 is a diagram showing a refractive index ellipsoid of a uniaxial nematic liquid crystal molecule.

FIG. 3 is a diagram showing a state where an electric field is applied to the polymer-dispersed liquid crystal layer shown in FIG.

FIG. 4 is a diagram showing an example of a configuration in which a voltage applied to a polymer-dispersed liquid crystal layer shown in FIG. 1 is made variable.

FIG. 5 is a diagram showing a configuration of an example of an imaging optical system for a digital camera using the variable focus lens according to the present invention.

FIG. 6 is a diagram showing a configuration of an example of an objective optical system for an electronic endoscope using the variable focus lens according to the present invention.

FIG. 7 is a diagram showing a configuration of an example of a variable focus diffractive optical element according to the present invention.

FIG. 8 is a view showing variable focus spectacles using the variable focus diffractive optical element according to the present invention as a spectacle lens.

FIG. 9 is a diagram showing a state where a voltage is applied to the variable focus diffractive optical element shown in FIG. 8;

FIG. 10 is a diagram showing spectacles using a conventional bifocal lens.

FIG. 11 is a view showing a modification of the variable focus glasses shown in FIG. 8;

FIG. 12 is a diagram showing another modified example.

FIG. 13 is a diagram illustrating a configuration of variable-focus glasses having a variable-focus lens using a twisted nematic liquid crystal.

FIG. 14 is a diagram showing an alignment state of liquid crystal molecules when a voltage applied to the twisted nematic liquid crystal layer shown in FIG. 13 is increased.

FIG. 15 is a diagram showing a configuration of two examples of a variable deflection prism according to the present invention.

FIG. 16 is a view for explaining a usage mode of the variable deflection prism shown in FIG. 15;

FIG. 17 is a diagram showing a configuration of an example of a variable focus mirror as a variable focus lens according to the present invention.

FIG. 18 is a diagram showing a configuration of an optical system using a conventional liquid crystal lens.

19 is a diagram showing a state where an electric field is applied to the liquid crystal lens shown in FIG.

FIG. 20 is a diagram showing a radial gradient inhomogeneous medium lens.

FIG. 21 is a diagram showing a refractive index distribution of the heterogeneous medium lens shown in FIG. 20;

FIG. 22 is a view showing a material of a heterogeneous medium lens.

FIG. 23 is a view for explaining a step of grinding a heterogeneous material by a centerless process.

FIG. 24 is a view for explaining a step of cutting a heterogeneous material by a cutting machine.

FIG. 25 is a diagram showing a state in which a cut heterogeneous material is bonded to a V block.

FIG. 26 is a diagram showing a state where a cut heterogeneous material is bonded to a gear.

FIG. 27 is a view for explaining a step of grinding a heterogeneous material using a surface grinder.

FIG. 28 is a view for explaining a fine grinding and polishing step of a heterogeneous material by a polishing machine.

FIG. 29 is a view for explaining a step of chamfering a heterogeneous material using a Dalai machine.

FIG. 30 is a view for explaining another example of the fine grinding and polishing process of the heterogeneous material by the polishing machine.

FIG. 31 is a view for explaining a step of grinding a heterogeneous material by a cider type centering machine.

FIG. 32 is a diagram for explaining a step of forming a toy used for manufacturing a spherical heterogeneous medium lens.

FIG. 33 is a diagram showing a state in which a heterogeneous material is attached to a yatoy.

FIG. 34 is a view for explaining a fine grinding and polishing step of a heterogeneous material by a polishing machine.

FIG. 35 is a view for explaining a step of attaching a heterogeneous material to a yatoy.

FIG. 36 is a view for explaining a curvature surface grinding step of a heterogeneous material by a curve generator.

FIG. 37 is a view for explaining a step of grinding the outer periphery of the heterogeneous material by the bell clamp centering machine.

FIG. 38 is a view illustrating a grinding step of the outer periphery of the heterogeneous material after the double-side polishing.

FIG. 39 is a view for explaining a step of grinding one surface of the heterogeneous material by the curve generator.

FIG. 40 is also a view illustrating a step of grinding the other surface of the heterogeneous material by the curve generator.

[Explanation of symbols]

 8a 1st surface 8b 2nd surface 9a 3rd surface 9b 4th surface 11 Variable focus lens 12a, 12b Lens 13a, 13b Transparent electrode 14 Polymer dispersed liquid crystal layer 15 Switch 16 AC power supply 17 Liquid crystal molecule 18 Polymer Cell 19 Variable resistor 21 Aperture 22 Lens 23 Solid-state image sensor 25 Front lens 26 Aperture 27 Variable focus lens 28 Back lens 29 Solid-state image sensor 31 Variable focus diffractive optical element 32, 33 Transparent substrate 32a First surface 32b Second surface 33a Third surface 33b Fourth surface 35 Variable focus glasses 35a Frame 36 Variable focus diffractive optical element 37, 38 Lens 39a, 39b Alignment film 45 Object 46 Distance measuring sensor 61 Variable deflection prism 62, 63 Transparent substrate 62a First Surface 62b second surface 63a third surface 63b fourth surface 65 variable focus The second surface 67a first surface 66b Ra 66,67 transparent substrate 66a third surface 67b fourth surface 68 reflecting film

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G02C 7/08 G02C 7/08 G02F 1/1333 G02F 1/1333

Claims (3)

[Claims] 1. A varifocal lens using a polymer-dispersed liquid crystal. 2. A variable focus diffractive optical element using a polymer dispersed liquid crystal. 3. A variable deflection prism using a polymer dispersed liquid crystal.