JPS6249302A - Optical element having variable focus - Google Patents

Abstract

PURPOSE:To keep the surface of an optical element spherical or required asherical by setting up the elastic modulus of an elastic body arranged on the projection side larger than that of an elastic body adjacent to the elastic body arranged on the projection side. CONSTITUTION:An elastic body 1 is constituted of two elastic bodies 1-1, 1-2 having different elastic module each other. Namely, the transparent elastic body 1 is stored in a case constituted of a bottom plate 2 made of glass or the like and side walls 3 and the elastic body 1 is constituted of the 1st and 2nd elastic bodies 1-1, 1-2 laminated in the optical axis (h) direction. An aperture plate 4 to be a deforming member for deforming the elastic body 1 is movably fitted to the side wall 3. An aperture part 4a is formed on the aperture plate 4 and the elastic body 1 stored in the aperture part 4a is projected or depressed by moving the aperture plate 4. In this case, the elastic modulus E1 of the 1st elastic body 1-1 arranged on the projection side is set up larger than the elastic modulas E2 of the 2nd elastic body 1-2 adjacent to the 1st elastic body 1-1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a variable focus optical element whose focal length is variable.

[Background technology]

Conventionally, as a variable focus lens, Japanese Patent Application Laid-Open No. 55-3685
7, in which an elastic container is filled with liquid and its shape is changed by the pressure of the liquid, and JP-A-56-110
403 or Japanese Patent Application Laid-Open No. 58-85415 using a piezoelectric material is known. However, the former so-called liquid lens requires a liquid reservoir and a pressurizing device, making it difficult to miniaturize, and has the drawback of large surface deformation due to gravity and vibration. Furthermore, the latter has the disadvantage that the amount of focal length variation is small.

In order to solve these drawbacks, the present inventor previously proposed a variable focus lens as shown in Figure 8. In the example shown in FIG. 8, 21 is a transparent elastic body, 22 is a glass plate, 23 is a side wall, 24 is an aperture plate having an opening Fffi 24a, and 21a is the elastic body 21 in the opening 24a of the aperture plate 4. is the surface of

FIG. 8(a) shows the initial state before deformation, and the opening r1 part 4
The elastic body surface 21a inside a has a predetermined shape such as a flat or spherical surface formed in advance. When the aperture plate 4 is moved in the direction of arrow A in the figure from the state shown in FIG. 8(a) to pressurize the elastic body 21, the elastic body 22 protrudes from the inside of the opening 24a. Elasticity within opening 24a.

The body surface 21a changes to a surface shape with a stronger curvature than the state shown in FIG. 8(a). Therefore, the elastic body surface 21 inside the opening 24a
By using a as a lens surface, it can be used as a variable focus lens. This example is useful because it is compact and allows a large amount of focal length variation with a small external force.

[Problem that the invention seeks to solve]

In order to use the element shown in Fig. 8 in an actual optical system, the aperture diameter should be set as close as possible to the element diameter a shown in Fig. 8 (a), and optically unnecessary parts other than the lens surface should be used. It is necessary to reduce the size of the entire optical system by reducing the number of parts.

However, when the aperture diameter is sufficiently small compared to the element diameter a, the elastic body surface 21a deforms into a spherical shape, but when the aperture diameter approaches the element diameter a, the elastic body surface 21a has a strong curvature at the same side. , deforms into a markedly aspherical shape. Also in this case,
The physical property value of the elastic body 21 that contributes to the surface shape during deformation is only Poisson's ratio, and the elastic modulus does not contribute to the surface shape during deformation.Therefore, even if the material of the elastic body 21 is changed, the surface shape during deformation will not change. They have similar tendencies.

The purpose of the present invention has been made in view of the above circumstances, and
An object of the present invention is to provide a variable focus optical element whose surface shape can always be kept spherical or a desired aspherical shape.

[Means to solve problems]

The variable focus optical element of the present invention includes a plurality of elastic bodies stacked in the optical axis direction, and a deformable member having an opening capable of deforming the surface of the elastic body by protruding or sinking the elastic bodies, Among the elastic bodies, the elastic modulus of the elastic body on the protruding side is made larger than the elastic modulus of the elastic body adjacent to the elastic body on the protruding side.

The present invention will be explained in detail below using the drawings.

FIG. 1 is a sectional view showing an example of the present invention.

The difference from the example shown in FIG. 8 is that the elastic body 1 is composed of two elastic bodies 1-1 and 1-2 having different elastic moduli. That is, a transparent elastic body 1 is housed in a container composed of a bottom plate 2 and a side wall 3 made of glass or the like, and the elastic body 1 is stacked with a first elastic body 1-1 stacked in the optical axis direction. Second
It is composed of an elastic body 1-2. Above the elastic body 1, an aperture plate 4 is movably provided on the side wall 3 as a deformation member for deforming the elastic body 1. The opening plate 4 has an opening 4
a is formed, and by moving the aperture plate 4, an aperture 4a is formed.
The elastic body l inside protrudes or sinks. Although FIG. 1 shows a state in which no pressure is applied, when pressure is applied to the elastic body 1 through the aperture plate 4, a part of the elastic body 1 becomes more convex lens-shaped than the aperture 4a according to the magnitude of the applied pressure. stand out. Conversely, when negative pressure is applied to the elastic body l through the aperture plate 4, the elastic body l becomes concave lens-shaped at the aperture 4a.

In the present invention, among the elastic bodies 1 made up of a plurality of elastic bodies, the adhesive modulus E1 of the first elastic body 1-1 on the protruding side is the same as that of the second elastic body 1-2 adjacent to the first elastic body 1-1. The elastic modulus E2 is configured to be larger than that of the elastic modulus E2. Here, the "protruding side" refers to the side where the surface of the elastic body 1 protrudes along the optical axis as the elastic body 1 is pressurized by the deformable member.

In the present invention, since El>E2, when the aperture plate 4 is moved downward in FIG. 1, the elastic body 1-2 tends to deform more. As described above, this deformation attempts to make the interface between the elastic bodies 1-2 and 1-1 into an aspherical shape with a strong curvature at the periphery. Along with this, elastic body 1-
1, the center part of the elastic body 1-2 rises to increase the force that tries to bend the elastic body 1-1 and the area of the interface between the elastic body 1-1 and the elastic body 1-2. When the elastic body 1-1 on which the force acts is thin, its main stiffness is the elongation stiffness of the membrane. Therefore, in this case, the elastic body 1-
1 tries to make the surface area as small as possible and deforms into a roughly parabolic shape. Furthermore, when the elastic body 1-1 is relatively thick, its bending rigidity tends to prevent sudden changes in curvature.

Therefore, in any case, the elastic body 1-1 is
Contrary to 2, it tries to deform into an aspherical shape with a weaker curvature at the periphery. Therefore, if the effect of making the elastic body l-1 an aspherical surface with a strong curvature at the peripheral portion and the effect of making the elastic body l-1 an aspherical surface with a weak curvature at the peripheral portion are balanced, the opening 4a of the elastic body 1-1 The inner surface 1a deforms while maintaining its nearly spherical shape.

Also, if the elastic modulus of the elastic body 1-1 is increased or made thicker, an aspherical surface with a weaker curvature can be obtained at the periphery during deformation, and conversely, if the elastic modulus is decreased or made thinner In this case, an aspheric surface with a strong curvature at the periphery can be obtained.

Therefore, if the initial shape and elastic modulus of the elastic bodies 1-1 and 1-2 are appropriately selected, a variable focus optical element that always deforms while maintaining a spherical or desired aspherical shape can be obtained.

Selection of such an initial shape and elastic modulus can be easily found using, for example, a structural analysis program based on the finite element method.

Surface 1a inside the opening 4a of the first outer body 1-1 on the protruding side
The shape when deformed is the first elastic body 1-1 and the second elastic body 1.
-2 Each initial shape and Poisson's ratio, and non-E 1 / of the elastic modulus of the 1911th elastic body 1-1 and the second elastic body 1-2
Determined by E2.

First elastic body 1-1. The Poisson's ratio of the second elastic body 1-2 is both 0.45 to 0.49 as the Poisson's ratio of a normal rubber elastic body.
In order to keep the deformed shape of the surface 1a inside the opening 4a spherical, it is desirable that 5<Ex t t/E2t2<100 (1), where tl and t2 are each first
This is the thickness of the elastic body 1-1 and the second elastic body l-2 along the optical axis. However, if the thickness of the first elastic body 1-1 is not uniform and is thick at the periphery, the desirable range of Eltl/E2t2 is slightly narrower than the range shown in equation (1); conversely, it is thinner at the periphery and thicker at the center. If the part is thick, then E 1t 1 /E2t2
The desirable range of is set slightly wider than the range shown in equation (1).

It is desirable that the values of tl and t2 satisfy t1≦t2.

If tl>t2, the force required to deform the elastic body 1-1 increases. Further, when the variable focus optical element of the present invention is used in a normal lens, the range is approximately 2 mm≦t1+t2≦30 mm. Although there is no particular lower limit value for tl, if the first elastic body 1-1 on the protruding side is too stiff, the strength may be insufficient or wrinkles may occur during molding.

The absolute values of the elastic modulus El and E2 of the elastic body 1-1.1-2 are determined in consideration of the magnitude of the force required for deformation and the influence of acceleration due to gravity and vibration. That is, when the elastic modulus EX and E2 are large, it is less susceptible to the influence of gravity, but the force required for deformation increases. Conversely, the elastic modulus E1. If E2 is small, the force required for deformation is small, but the deformation due to the influence of gravity becomes large, and since it is soft, it becomes difficult to form the initial shape accurately during molding.

From these points, the value of E2 is 102-107 (N/m
), more preferably 103
~106 (N/m') - ['The value of the certain 0 elastic modulus E1 is determined by the value of the gloss modulus E2 and the desired shape of the surface 1a upon deformation. Therefore, if the desired shape is spherical, the elastic modulus E1
The value of is determined from equation (1).

An example of the numerical value is 0. The elastic bodies are preformed in the shape shown in FIG. 2(a), and the thicknesses of the elastic bodies 6-1 and 6-2 along the optical axis are each 1 mm.

The surface 6a inside the opening 4a of the elastic body 6-1 and the interface between the elastic bodies 6-1 and 6-2 are both spherical surfaces with a radius of curvature of 50 mm in a non-pressurized state. The element diameter a is 25 mm, the aperture diameter is 20 mm, and the Poisson's ratio of the l3In material 6-1.6-2 is 0.47.

When the distance between the opening plate 4 and the bottom plate 2 is reduced by ΔZ from this state to the state shown in FIG. 2(b), how is the shape of the surface 6a inside the opening 4a of the elastic body 6-1 deformed? This was investigated using a structural analysis program using the finite element method.

As a result, the ratio of the elastic moduli of the elastic bodies 6-1 and 6-2 is set to E1/
E2=60. (E t=6X105 (N/m')
.

When E2=104 (N/m')), Δz=O~
The amount of deviation from the spherical surface was always less than 10 lm within a range of 0.4 mm. The radius of curvature of the surface 6a when ΔZ = 0.4 mm is approximately 30.2 mm, and when ΔZ is 0 to
If the radius of curvature is changed between 0.4 mm and 0.4 mm, the elastic body surface 6a will deform while maintaining an approximately spherical shape within a radius of curvature of 50 to 3 mm.
If used as a reflective surface by Q vapor deposition, etc., the distance between the aperture plate 4 and the bottom plate 2 can be changed by 0.4 mm.
A refractive power change of 6 days is obtained. In addition, if the elastic body surface 6a is used as a refractive surface, 1 elastic body 6-1.6-
If the refractive index of 2 is 1.5, a change in refractive power of 6.6 diopters is obtained.

In this numerical example, the first
The figure shows the case where there is no side wall 3 and the side surfaces of the elastic bodies 6-1 and 6-2 are not constrained, but the ratio E 1 / E 2 should be made slightly thicker, about L, E 1 / E 2 = lOO. Similarly, it can be deformed while maintaining its spherical shape.

Next, other embodiments of the present invention will be described.

FIG. 3 shows an example in which the two elastic body surfaces 7a and 7b are both variable in shape, 7-1 and 7-2.

Each of 7-3 is a transparent i-flexible body, and the elastic body 7-1 on the protruding side and the elastic body 7-2 adjacent to 7-3 have the smallest elastic modulus. 4-1.4 The elastic modulus of the elastic body 7-1 and the elastic modulus of the elastic body 7-2 may be the same or different.
-2 is an aperture plate which is a deformable member; in the illustrated example, the aperture plate 4-1 is fixed to the side wall 3;
2 changes the shapes of the two surfaces 7a and 7b simultaneously by moving along the inner surface of the side wall 3 in the optical axis direction.

Both of the aperture plates 4-1 and 4-2 may be provided movably.

FIG. 4 shows an example in which an aperture plate is provided in the elastic body 8 as a deformable member. The aperture plate 9 is bonded to each of the elastic bodies 8-1, 8-2, and by changing the distance between the bottom plate 2, such as glass, and the aperture plate 9, the lens surface can be deformed in the same way as in the embodiment shown in FIG. can.

FIG. 5 shows an example in which an external force is applied from the outer periphery of the elastic body 10, and 12 is a side wall made of a cylindrical piezoelectric element.
By expanding and contracting the inner diameter of the side wall 12 in accordance with the applied voltage, the surface 10a and fob of the elastic body 10 are deformed. In this embodiment, the side wall 12 is the deformable member. Also,
The elastic modulus of the elastic bodies 10-1 and 10-3 on the protruding side is larger than the elastic modulus of the adjacent elastic body 10-2.

Natural rubber or synthetic rubber can be used as the rubber material used in the present invention, but it is preferable to use one with a low elasticity in order to easily obtain large elastic deformation. In this case, it is desirable to use a material with good transparency. As such an elastic material, silicone rubber, ethylene propylene rubber, etc. are suitable. It is useful to vary the degree of crosslinking in order to obtain a plurality of rigid bodies with different moduli of elasticity.

Examples of the elastic body that can be used in the present invention include diene compounds, rubbers synthesized by copolymerization of dienes and other vinyl compounds, and those obtained by crosslinking these by sulfur vulcanization, peroxide, etc.

In addition, as an elastic body, ethylene can be used with α-olefins, dienes, polar monosubstituted vinyl compounds (e.g. acrylic acids,
(methacrylic acids, styrene, vinyl chloride, vinyl ether, etc.) and di-bent vinyl compounds (e.g., maleic acids) to significantly reduce or eliminate the crystallinity of ethylene. Examples of polymers include

Furthermore, polyisobutyne, atactic polypropylene, and polyvinyl chloride mixed with a large amount of plasticizer are used as elastic bodies.
Copolymers of two or more acrylic acids or acrylic esters, copolymers of two or more acrylic acid derivatives containing Mizushima or high boiling point solvents, silicone polymers (e.g. dimethyl silicone, diphenyl silicone, etc.) )
, phosphazene polymers, and the like.

As an elastic body other than a polymer, an elastic liquid obtained by dissolving a hydrocarbon in aluminum soap such as aluminum laurate can also be suitably used.The elastic modulus of the elastic body can be adjusted in various ways depending on the molecular weight and degree of crosslinking. can do.

The elastic body used in the present invention will be explained in more detail.

If a material having an elastic function i is used as a wheel, the complex elastic modulus G, the storage elastic modulus G' and the loss elastic modulus G'', then G = G
' + i G ''. G'' is a term due to the fact that the added energy is stored in the system as internal energy, and G '' is a term due to the fact that it is dissipated as thermal energy at that time. Transformation From the point of view of recovery, G''〉
G'' is preferred, and G')) G''zO is more preferred.

The elastic body used in the variable focus optical element of the present invention is preferably selected from the group consisting of a rubber polymer, a polymer melt, a polymer solution, and a polymer gel. , the same kind of these elastic bodies,
Or use a combination of different types of elastic bodies.

The elastic modulus of the elastic body can be changed depending on the degree of crosslinking of the above-mentioned substance, the molecular bond between crosslinking points, the molecular weight, the concentration of the polymer solution, etc. Elastic force is produced by chemically bonding molecular chains and crosslinking them.

Alternatively, as is generally well known, when the molecular weight of a polymer compound exceeds a certain value, a phenomenon called entanglement of polymer chains produces an effect similar to crosslinking. Although the entanglement phenomenon differs depending on the type of polymer, it occurs when the number of molecules is 12,000 or more, and is widely observed in polymer melts and polymer solutions.

In addition to the elastic bodies mentioned above, the following elastic bodies can be used in the present invention.

polybutadiene, polyisoprene, polychloroprene,
Homopolymers of diene compounds such as polynorbornadiene,
and butadiene-styrene, imprene-imbutene,
Rubber substances such as diene copolymers obtained by copolymerizing a diene monomer such as butadiene-acrylic acid or its ester, and one or more vinyl monomers, and α such as ethylene and propylene. - A polymer obtained by copolymerizing olefins, and may be copolymerized with a small amount of a diene compound. Also included are polyethylene copolymers in which the crystallinity of polyethylene is significantly reduced or eliminated by copolymerizing ethylene with a large number of polar vinyl monomers.

``Polysiloxanes other than hydrocarbons, polyphosphazenes, etc. are also suitably used.

A polymer melt is a thermoplastic resin that is liquefied at a temperature above its melting point, and is a material that is made of a thermoplastic resin that is liquefied at a temperature above its melting point.
Polyamide, polystyrene, polyvinyl acetate, etc. are used. The polymer melt does not necessarily have to be a homopolymer, and may be copolymerized with one or more monomers other than the main constituent polymer.

The above-mentioned polymers can be prepared using chemical methods such as peroxide compounds, sulfur, etc.
The i-strength is adjusted by crosslinking using physical methods such as light or radiation, and in thermoplastic resins, monomers having functional groups capable of crosslinking are copolymerized in advance.
The crosslinking reaction can be carried out by chemical methods or physical methods.

Although it varies depending on the type and molecular weight of the polymer, a polymer solution obtained by dissolving a polymer compound at a concentration higher than that at which the molecules are not dispersed may also be used. Alternatively, a so-called polymer gel can be produced by impregnating a crosslinked polymer with an appropriate solvent. Typical examples include acrylic esters, so-called acrylic gels made of acrylic esters, etc., swollen with water.

The device of the present invention has a structure in which two outer bodies of different types are laminated. For example, combinations of vulcanized rubbers with different sulfur additives used for crosslinking, combinations of vulcanized rubber and vulcanized rubber swollen with solvents, combinations of two molten polymers with different molecular weights, polyester and a combination of polyester elastomer and the like.

Elements made of rubber-based polymers, elements made of swollen polymer gel, etc. are suitably used for elements that operate at relatively low temperatures, while elements made of molten polymers are operated at high temperatures. Suitable for use in devices. Polysiloxane is most preferably used as an element that can operate in a wide range from low to high temperatures.

Next, a preferred method for manufacturing the optical element according to the present invention will be described with reference to FIGS. 6 and 7.

In terms of performance, the optical element in the present invention also has the following characteristics as an optical element:
It is necessary to manufacture the shape of the surface of the elastic body with high precision. For this reason, it is desirable, for example, to form the elastic body 1-1 in FIG. 1 with high accuracy using a mold or the like, and then mold the elastic body 1-2 into the mold.

To give an example of the manufacturing method of the element shown in Fig. 2, first,
As shown in FIG. 2A, an elastic body 6-1 shown in FIG. 2 is molded between an upper mold 13, a lower mold 14, and a side mold 15. Various molding methods such as casting and injection are possible. It is desirable that the mold surfaces of the upper mold 13 and the lower mold 14 be subjected to appropriate mold release treatment, and in particular, the mold surface of the upper mold 13 should be coated with Teflon or the like to have better mold release properties than the mold surface of the lower mold 14. After hardening the elastic body 6-1, as shown in Fig. 6 (
After removing the upper mold 13 as shown in b), place the bottom plate 2 made of glass or the like as shown in FIG. 6(c), and place the elastic body shown in FIG. The raw material for the elastic body 6-2 for molding 6-2 is injected from the injection port provided in the side mold 15 or the part of the bottom plate 2 where the light beam does not pass.
After the elastic body 6-2 is cured, the lower mold 14 and side plate 15 are removed and placed in the side wall 16 prepared in advance as shown in FIG. 6 (%). In the case of the variable focus optical element shown in FIG. 6(d), the focal length can be changed by moving the bottom plate 2. In the case of Fig. 6 (cherry blossoms), the side wall 16
becomes the deformable member.

Furthermore, it is also possible to use the so-called spinning casting method to form the elastic body 6-1 in FIGS.
After curing the raw material No.-1, the process moves to the step shown in FIG. 6(C).

Note that the thickness of the elastic body on the protruding side used in the present invention does not need to be uniform, and the surface shape during deformation can be controlled by providing an appropriate thickness distribution.

Further, it is desirable to use a very soft material for the elastic body adjacent to the elastic body on the protruding side, and as a result, it may become sticky and cannot be released from the side mold 15 shown in FIG. 6. In such a case, it is effective to change the shape of the -F mold 13 so that the harder elastic body 6-1 is in contact with the side mold 15 as shown in Figure tJIJ1.

Next, embodiments of the present invention will be described in more detail.

Example 1 Silicone rubber (product name: KE106. Shin-Etsu Ihi f
T * "49) to M, bK (product 51.: Cat a l
After adding 10% by weight of v st RG (manufactured by Shin-Etsu Chemical Co., Ltd.), the mixture was stirred and defoamed under vacuum, as shown in Figure 6 (a).
It is stored between the upper mold 13, lower mold 14, and side mold 15 shown in 6.
It was left to stand at 5° C. for 4 hours and cured to form a transparent elastic body 6-1. The inner diameter of the side mold 15 is 25 mm, and the inner diameter of the upper mold 13. Lower mold 14
The diameter C of the curved portion of both is 20 mm, and both are spherical surfaces with a radius of curvature of 50 mm.
The wall thickness on the optical axis of the upper mold 13 is 1 mm, and the mold surface of the upper mold 13 is coated with Teflon to improve mold releasability.

Next, as shown in FIG. 6(b), the upper mold 13 is removed, silicone (trade name: KE106, manufactured by Shin-Etsu Chemical), catalyst (
Product name: CatalystRG, manufactured by Shin-Etsu Chemical Co., Ltd.), Silicone rubber (Product name: KE104 Gel, manufactured by Shin-Etsu Chemical Co., Ltd.) Catalyst (Product name: Catalyst 104)
(manufactured by Shin-Etsu Chemical) at a weight ratio of 1'O:l:100:10
The mixed and vacuum-defoamed solution is placed between the glass plate 2, the outer body 6-1 and the side mold 15 as shown in FIG. 6(C),
Leave to stand at 40°C for 72 hours and harden to form a transparent elastic body 6-
It was set as 2. The thickness of the elastic body 6-2 along the optical axis is 4 mm.

Next, the lower mold 14 and the side mold 15 were removed and housed in the side wall 16 as shown in FIG. 6 (cl). When the glass plate 2 was moved in the direction along the optical axis and the change in the shape of the surface 6a of the elastic body 6-1 was measured, the glass plate 2 was moved in the direction of applying pressure to the elastic body 6 up to a movement% of 0.4 mm. When the elastic body 6-1
Surface Examples 2 to 7 Using the polymers shown in Table 1, optical elements shown in FIG. 2C&) were created. In any of the optical elements of Examples 2 to 7, the thickness of the elastic body 6-1 along the optical axis is 1 mm.
-2 had a wall thickness of 4 mm on the optical axis. In both cases, the element diameter a was 25 mm, and the aperture diameter was 20 mm.

The elastic body of each example was molded as follows. That is,
The polyethylene of Example 2 and the polyamide of Example 3 were press molded at a temperature of 270°C, the polyethylene of Example 4 was press molded at a temperature of 190'C, and the polyvinyl acetate of Example 5 was molded at 90°C in a N2 stream. After pouring into a mold and curing, the silicone rubber of Examples 6 and 7 was heated to RT.
The V thermosetting resin was poured into a mold, sulfurized, and molded.

In Examples 2, 3, 4.5, and 7, one type of elastic body was used as elastic body 6-1 and elastic body 6-2 with different elastic modulus. In Example 6, two types of elastic bodies, polyisobutylene and silicone rubber, were used as elastic body 6-1 and elastic body 6-2 by having different elastic moduli.

Now, in this way, the glass plate 2 is moved by 0.4 in the direction along the optical axis.
When the surface 6a of the elastic body 6-1 was examined for changes in shape by moving the elastic body 6-1 up to mm, it was found that the elastic body 6-1 was deformed while maintaining its substantially spherical shape.

Further, the focal length of each example was measured at two points where the radius of curvature of one surface 6a was 50 mm and 30 mm. The results are shown in Table 1.

[Effects of the Invention] As described above, according to the present invention, by selecting the initial shape and elastic modulus of the IA-layered elastic body, a variable focus optical element that can be deformed while maintaining a spherical or desired aspherical shape can be obtained. It will be done. In addition, the variable focus optical element of the present invention can be manufactured with higher precision than a so-called liquid lens, and the elastic body on the protruding side can support the effects of gravity, vibration, etc., so there is no large surface erosion. does not occur.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an example of the variable focus optical element according to the present invention, FIGS. 2(a) and 2(b) are cross-sectional views showing other examples of the variable focus optical element according to the present invention, and FIG. The figure shows another example of the variable focus optical element in the present invention,
FIG. 4 is a sectional view of an example in which a pair of aperture plates are provided, and FIG. 4 is a sectional view of an example in which an aperture plate is provided in an elastic body. Figure 5 shows another example of the variable focus optical element according to the present invention.
A cross-sectional view of an example in which a cylindrical piezoelectric element is used as a deformable member, and FIGS. 6(a), (b), (c), and (d) are cross-sectional views showing an example of the manufacturing process of the variable focus optical element in the present invention. 6(a) is a diagram showing the process of molding the elastic body on the protruding side, FIG. 6(b) is an L-shaped diagram of FIG. 6(a), and FIG. 6(C) is a diagram showing the process of molding the elastic body on the protruding side. FIG. 6(d) is a cross-sectional view showing an example of the variable focus optical element of the present invention manufactured by the steps shown in FIGS. 6(a) to (C). , FIG. 7 is a sectional view showing the process of molding the protruding elastic body using another upper mold, and FIGS. 8(a) and 8(b)
FIG. 2 is a cross-sectional view showing an example of the previously proposed optical element. 1.6.7.8.10---One bullet outer body 2---Bottom plate 3.12---One side wall 4.9---One opening plate 13---One upper mold 14--- One lower mold 15---One side mold Uri (b) Figure 6 and a) (1)) (C) (d) 8th

Claims (2)

[Claims] (1) Consisting of a plurality of elastic bodies stacked in the optical axis direction and a deformable member having an opening that can deform the surface of the elastic body by protruding or sinking the elastic body, the protruding side of the elastic body A variable focus optical element characterized in that the elastic modulus of the elastic body is made larger than the elastic modulus of the elastic body adjacent to the elastic body on the protruding side. (2) The variable focus optical element according to claim 1, wherein the elastic body is selected from the group consisting of a rubber polymer, a polymer melt, a polymer solution, and a polymer gel.