JP2003014909A - Variable focal distance lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable focal distance lens in which the focal distance is variable with a single lens. SOLUTION: The lens is provided with transparent resin plates 1 and 2 which are made of two transparent elastic bodies which are deformed in the direction of normal line of the respective faces and oppositely arranged, and a fluid 7 composed of transparent fluidized filler inserted between the transparent resin plates 1 and 2. The function as a lens is given by varying the shape of faces formed by the transparent resin plates 1 and 2 into a spherical face or an aspherical face by varying the volume of the transparent fluidized filler.

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, and more particularly to a variable focus lens used in optical equipment, optical pickups and the like.

[0002]

2. Description of the Related Art Generally, optical instruments such as glasses and microscopes, and CD-ROMs, CD-Rs, CD-RWs and DVD-RAs.
Ordinary lenses used for an objective lens of an optical pickup device of an optical disk drive such as M, DVD-ROM, or the like are each formed by polishing a transparent optical material such as glass or plastics, or by press molding or injection molding. The surface is shaped and the entire lens is made of a uniform glass material.

By the way, an objective lens such as an optical pickup is an object on which light is incident without changing the focal length in order to focus light from a light source such as an LD.
Focusing is performed by moving the objective lens close to or away from the ROM or the like and changing its position and direction.

[0004]

However, each of the conventional optical lenses is formed with a predetermined focal length by itself. To change the focal length, a plurality of lenses are combined or a special lens is used. It had to be processed.

Also, in the case of a single lens having a plurality of focal lengths, there is a limit to the number of focal points that can be formed, and it is difficult to design and manufacture.

On the other hand, in the optical pickup device, an actuator for moving the objective lens toward or away from the light incident surface is required, which makes the device large in size.

Therefore, a technical object of the present invention is to provide a variable focus lens which can change the focal length with a single lens.

[0008]

According to the present invention, two transparent elastic bodies (1, 2; 21, 22) arranged facing each other, which are deformable in the normal direction of each surface, are provided. Elastic body (1,
2; 21, 2), and a fluid transparent filler (7) inserted between the elastic bodies (1, 2; 21, The variable focus lens (10, 20, 30) is obtained by changing the surface shape formed by (22) to a spherical surface or an aspherical surface to give the function of the lens.

Further, according to the present invention, in the variable focus lens (10, 20, 30), the elastic body (1,
2; 21 and 22), the variable focus lens (10, 20, 30) is obtained, which is configured to be deformable in the normal direction of each surface provided.

Further, according to the present invention, in the variable focus lens (10, 20, 30), the pressure change of the fluid transparent filler (7) changes the volume of the fluid transparent filler (7). A variable focus lens (10, 20, 30) is obtained which is characterized in that the pressure is controlled by a pressure control means.

Further, according to the present invention, in the variable focus lens (10, 20, 30), the pressure control means includes a syringe (6), a manual pump (11), a piezoelectric actuator, an electric pump, an electromagnetic pump, A variable focus lens (10, 20, 30) characterized by including any one of the magnetostrictive actuator and the magnetostrictive actuator.

According to the present invention, in any one of the variable focus lenses (10, 20, 30), the elastic bodies (1, 2; 21, 22) are made of resin. A variable focus lens (10, 20, 30) is obtained.

The reference numerals in the parentheses are given for easy understanding, and are merely examples, and the present invention is
It is not limited to these.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1A, 1B and 1C are schematic sectional views showing the structure of a variable focus lens according to the first embodiment of the present invention.

Referring to FIG. 1B, the variable focus lens 10 has a parallel plate shape and closes the first and second transparent resin plates 1 and 2 made of a pair of elastic bodies and their peripheries. And the ring-shaped flange 3 provided in such a manner that one end communicates with the inside of the facing surfaces of the first and second transparent resin plates 1 and 2 through the through hole 4 provided in the flange 3 and the other end is manually operated. It is provided with a connecting tube or an injection needle 5 connected to the other end of a syringe 6 as a pump.

The space between the syringe 6, the connecting tube 5, and the first and second transparent resin plates 1 and 2 is filled with a transparent fluid.

As the first and second transparent resin plates 1 and 2, a polycarbonate plate, an acrylic plate, or the like can be used, but if they are transparent materials having elasticity having mutually equal elastic coefficients, they are It is not limited.

A normal syringe can be used as the syringe 6 as the pressure control means, but the piston is mechanically moved by a piston to increase the volume of the contained fluid, thereby increasing the pressure manually. A pump or the like can be used.

The syringe 6 is capable of maintaining its state and releasing pressure when the proper focal length of the lens is obtained.

From the state of FIG. 1 (b), when the piston of the syringe 6 is pushed in as shown in FIG. 1 (a) as indicated by the arrow 8, the first and second transparent resin plates 1 and 2 are Due to the increase of the internal pressure due to the increase of the volume of the fluid, each of them bends outward to form a biconvex lens shape.

On the other hand, from the state of FIG. 1 (b) to FIG.
As shown in FIG. 3, when the piston is pulled out to the syringe 6, the pressure decreases due to the volume reduction of the fluid inside, and the first and second
The transparent resin plates 1 and 2 are curved inward to form a biconcave lens.

Further, from the state of FIG. 1 (c), the syringe 6
When the piston is released, it returns to the shape shown in FIG.

As described above, in the first embodiment of the present invention, not only the spherical surface but also the spherical surface can be obtained by partially changing the surface thickness of each of the transparent resin plates 1 and 2 made of two elastic bodies.
So-called aspherical rotating bodies such as paraboloids and hyperboloids can be formed.

Further, in the variable focus lens according to the first embodiment of the present invention, the curvature can be freely changed by plus or minus by changing the pressure of the fluid enclosed therein.

By changing the pressure of the fluid 7 using this characteristic, the focal length of the lens can be changed freely.

In the first embodiment of the present invention, the syringe 6 is used as the pressure control means for the fluid, which is the filler, but the side surface of the lens is so-called bag-shaped. , Simple means such as pushing the rod by electromagnetic means, electric means using static electricity or manually
It can be used similarly.

Further, as the pressure control means, it is possible to change the pressure by an electric method such as an electric pump or an electric actuator.

Further, by using a piezoelectric vibrator or the like to change and oscillate the pressure at a high speed and change the focal length at an unstoppable speed, it is possible to focus on any height of an object having a height difference. You can prompt for the image that was there.

Further, in the first embodiment of the present invention, the surface thickness distributions of the transparent resin plates 1 and 2 made of an elastic material are changed concentrically, but in the present invention, it is perpendicular to the optical axis. By giving a symmetrical change to this axis, it is possible to have a characteristic like a cylindrical lens.

FIGS. 2A, 2B and 2C are schematic sectional views showing the structure of a variable focus lens according to the second embodiment of the present invention.

Referring to FIG. 2C, the varifocal lens 20 has a pair of elastic first and second transparent resin plates 1 and 2, and a ring-shaped member provided so as to close the peripheries thereof. Flange 3 and through-hole 4 provided at one end with flange 3
And a connecting tube 5 that communicates with the insides of the facing surfaces of the first and second transparent resin plates 1 and 2 through the other end and has the other end connected to the other end of the manual pump 11.

Further, the manual pump 11 and the connecting tube 5
The transparent fluid 7 is filled in the spaces between the first and second transparent resin plates 1 and 2. The manual pump 11 as the pressure control means is formed of a balloon-shaped fluid reservoir, but a manual pump having a structure used for a blood pressure monitor or the like can be used.

As the first and second transparent resin plates 1 and 2 used in the second embodiment of the present invention, a polycarbonate plate, an acrylic plate or the like is used as in the first embodiment. However, as long as they have elasticity equal to each other, they are not limited thereto.

From the state of the concave lens in FIG.
As shown in (b), when the manual pump 11 is squeezed as shown by an arrow 13, the first and second transparent resin plates 1,
Both 2 are deformed from a curved state to a parallel plate while keeping parallel to each other.

That is, both the first transparent resin plate 1 and the second transparent resin plate 2 are deformed to be flat.

Further, as shown by an arrow 12 in FIG. 2A, when it is squeezed, it becomes a biconvex lens shape having a convex outer surface.

Also in the second embodiment of the present invention, the same pressure control means as in the first embodiment can be modified, and the same effect can be obtained although the surface shape is different.

FIGS. 3A, 3B, and 3C are schematic sectional views showing the structure of the variable focus lens according to the third embodiment of the present invention.

Referring to FIG. 3C, the variable-focus lens 30 is a concave lens, and is provided so as to close the first and second transparent resin plates 21 and 22 having a pair of elasticity and the periphery thereof. Ring-shaped flange 3 and flange 3 at one end
A communication tube 5 which communicates with the inside of the facing surfaces of the first and second transparent resin plates 21 and 22 through the through hole 4 provided in There is.

Further, the manual pump 11 and the connecting tube 5
And in the space between the first and second transparent resin plates 21 and 22,
It is filled with a transparent fluid 7.

The first and second transparent resin plates 21 and 22 are transparent elastic bodies having different curvatures or different elastic coefficients, and for example, a polycarbonate plate, an acrylic plate or the like is used as the material thereof. However, it is not limited thereto as long as it has elasticity.

Further, the manual pump 1 as a pressure control means
As 1, a manual pump or the like having a structure similar to that used in the sphygmomanometer or the like of the second embodiment can be used, but it is also possible to mechanically apply pressure in place of the hand. .

When the manual pump 11 is squeezed from the state shown in FIG. 3 (c) as shown in FIG. 3 (b) as indicated by an arrow 15, the first transparent resin plate 21 bends outward and Although the second transparent resin plate 22 has a slightly smaller curvature, it hardly deforms. As a result, a neutral state in which both surfaces have the same curvature and is neither a concave lens nor a convex lens is formed.

Further, as shown in FIG. 3 (a), when pressure is further applied by the manual pump 11, the outer surface of the first transparent resin plate 21 is further curved outward and the second transparent resin plate 22 is formed. Deforms to become even flatter.
As a result, the convex lens is in a meniscus state.

In addition, in the third embodiment of the present invention shown in FIG. 3, the surface shape of the second transparent resin plate 22 is fixed in a concave state, and the first transparent resin plate 21 is slightly outward. If it is configured to be curved, it acts as a concave lens for myopia when the force applied to the manual pump 11 is removed,
When a force is applied, the lens power is lost as shown in FIG. 3 (b), and further, as shown in FIG. 3 (a), the lens is deformed to form a convex lens for hyperopia.

Also in the third embodiment of the present invention, the manual pump 11 can be modified in the same manner as in the first and second embodiments, and the lens shape is different but the surface shape is different. The same effect can be obtained by changing the.

As described above, in the variable focus lens according to the first to third embodiments of the present invention, 2
By varying the hardness and surface thickness of the transparent resin plates 1, 21, 21, 22 made of a single elastic body and giving an initial curvature, various types such as plano-convex, plano-concave, biconvex, biconcave, and meniscus can be obtained. It is possible to create various surface configurations.

Further, in the present invention, the focal length can be continuously and freely changed by changing the pressure of the fluid 7 to be filled, so that the CD and the DVD can be changed.
Can be applied to a bifocal lens, and dispersion of glass materials can be corrected.

Furthermore, in the present invention, not only the application to the optical disk device but also the application to the spectacle lens is easy. For example, automatic switching for both perspective can be achieved by combining it with a method of detecting the parallelism of the lines of sight of the left and right eyes.

Further, in the present invention, astigmatism can be dealt with by incorporating the elements of the cylindrical lens.

[0052]

As described above, in the present invention, not only spherical surfaces but also so-called aspherical surfaces such as paraboloids and hyperboloids are obtained by partially changing the surface thickness of each of the two elastic bodies. A rotating body can be formed, and the curvature of the fluid can be freely changed by changing the pressure of the fluid. By using this characteristic, the pressure of the fluid can be changed to change the lens. It is possible to provide a variable focus lens capable of freely changing the focal length of the.

Further, in the present invention, the hardness and surface thickness of the two elastic bodies are made different, and the initial curvature is given.
Various surface configurations such as plano-convex, plano-concave, biconvex, biconcave, and meniscus can be created to provide a variable focus lens.

Further, in the present invention, instead of changing the surface thickness distribution of the elastic body on the concentric circles, the elastic body is changed symmetrically with respect to the axis perpendicular to the optical axis, so that it has characteristics like a cylindrical lens. Can be made.

[Brief description of drawings]

1A, 1B, and 1C are schematic cross-sectional views showing the configuration of a variable focus lens according to a first embodiment of the present invention.

2 (a), (b), and (c) are schematic cross-sectional views showing the configuration of a variable focus lens according to a second embodiment of the present invention.

3A, 3B, and 3C are schematic cross-sectional views showing the configuration of a variable focus lens according to a third embodiment of the present invention.

[Explanation of symbols]

1,21 1st transparent resin plate 2,22 Second transparent resin plate 3 flange 4 through holes 5 Communication tube 6 syringes 7 fluid 10, 20, 30 variable focus lens 11 Manual pump

Claims (5)

[Claims] 1. A deformable transparent elastic body disposed opposite to each other, and a fluid transparent filler inserted between the elastic bodies, the pressure of the fluid transparent filler being controlled. A varifocal lens characterized by changing the surface shape formed by the elastic body into a spherical surface or an aspherical surface so as to have a lens function. 2. The variable focus lens according to claim 1, wherein the elastic body is configured to be deformable in a direction normal to each surface of the elastic body. 3. The variable focus lens according to claim 1, wherein the pressure change of the fluid transparent filler is performed by a pressure control unit that changes the pressure by changing the volume of the fluid transparent filler. Variable focus lens that is characterized. 4. The variable focus lens according to claim 3, wherein the pressure control means includes any one of a manual pump, a piezoelectric actuator, an electric pump, an electromagnetic pump, and a magnetostrictive actuator. Variable focus lens. 5. The variable focus lens according to claim 1, wherein the elastic body is made of resin.