JP2000075111A - Variable focus lens device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of a temp. drift phenomenon of a variable focus lens device having variable focus lens parts consisting of transparent elastic bodies and working fluid and to improve the heat resistance thereof. SOLUTION: The variable focus optical element 10 consisting of variable focus lens parts 10a which are changed in their foci by a shape change by external force and actuator parts 10b which change the shape of the lens parts 10a by imparting external force to the lens parts 10a is housed and held in the housing space part of a thermally insulating mechanism 20 to shut off the heat from the outside, by which the occurrence of the temp. drift phenomenon of the lens parts 10a is suppressed and the heat resistance is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a varifocal lens device for variably controlling the focus of a lens in a varifocal lens unit. The varifocal lens device is a microscope, a microscope camera device, and other medical and industrial devices. It is applied to a wide range of fields, such as a catheter, an optical lens mounted on the tip of a probe, and the like.

[0002]

2. Description of the Related Art As one type of a variable focus lens device, as disclosed in Japanese Patent Application Laid-Open No. Sho 60-84502, a variable focus lens unit formed of a transparent elastic material such as styrene rubber is provided. There is a variable focus lens device. As another type of the variable focus lens device, Japanese Patent Application Laid-Open No. 63-22 / 1988
As disclosed in Japanese Patent Application Laid-Open No. 9401, there is a variable focus lens device provided with a variable focus lens unit in which a transparent working fluid is sealed in an accommodation space formed by a transparent elastic film or the like.
Incidentally, the latter applicant has also proposed the latter type of variable focus lens device in Japanese Patent Application No. 8-296780.

[0003]

By the way, in the variable focal length lens device in which the lens of the variable focal length lens portion is formed of a transparent elastic body or a working fluid as described above, the elastic body or the working fluid has a temperature lower than the ambient temperature of the apparatus. There is a problem that a so-called temperature drift phenomenon occurs in which the lens expands or contracts in accordance with the change, and the optical characteristics of the lens largely change.

Further, in the variable focus lens device, for example, when applied to a medical instrument such as a medical endoscope, the medical instrument is subjected to heat sterilization in an autoclave or the like each time it is used. Therefore, there is a problem that the temperature of the heat sterilization treatment cannot be sufficiently tolerated. Therefore,
SUMMARY OF THE INVENTION An object of the present invention is to suppress the occurrence of a temperature drift phenomenon in a variable focus lens device that constitutes a lens of a variable focus lens unit using a transparent elastic body or a working fluid, and to reduce the possibility of heat when used in medical instruments. The purpose is to ensure sufficient heat resistance for sterilization.

[0005]

According to the present invention, a varifocal lens device includes a varifocal lens unit whose focal point changes due to a shape change due to an external force of an elastic lens, and a varifocal lens unit integrated with the varifocal lens unit. An actuator unit that constitutes an optical element and changes the shape of the lens by applying an external force to the lens, and a heat insulating mechanism that adiabatically holds the variable focus optical element. By adopting it, the occurrence of the temperature drift phenomenon in the varifocal lens portion is suppressed and the heat resistance is improved.

[0006]

Therefore, according to the variable focus lens device according to the present invention, the function of the heat insulating mechanism for adiabatically holding the variable focus optical element allows the variable focus lens unit constituting the variable focus optical element to function. The occurrence of the temperature drift phenomenon can be suppressed, and the heat resistance of the variable focus optical element can be improved.

Thus, in the variable focus lens device according to the present invention, the actuator section is composed of a plurality of ring-shaped elastic plates each having a through hole in the center and a piezoelectric plate bonded to at least one surface of the elastic plate. A piezoelectric deformation element, an outer peripheral connecting member that connects the outer peripheral edges of the piezoelectric deforming elements in a stacked state, and an inner peripheral edge of each piezoelectric deforming element that is connected in a stacked state to form an optical path to the variable focus lens unit and to be variable. It can be constituted by an inner peripheral connecting member that applies an external force to the lens of the focusing lens unit.

According to this structure, since the inner connecting member connecting the inner peripheral sides of the piezoelectric deformation elements forms a cylindrical optical path at the center, the variable focus lens can be formed by a single actuator. Unit can be driven. In this case, since the actuator unit can be coaxially arranged on the lens of the variable focus lens unit, the driving force generated by the actuator unit can be uniformly applied to the lens of the variable focus lens unit all around. No asymmetric distortion occurs in the lens.

Further, in the variable focus lens device according to the present invention, the variable focus lens portion includes a disc-shaped transparent elastic film, a pressing elastic film having a light transmitting portion in the center, and a transparent elastic film. It can be composed of a film and a working fluid sealed in a closed space formed by the elastic film for pressurization.
According to this configuration, by driving the actuator unit,
A variable focus lens capable of variably controlling the focus of the lens by deforming the transparent elastic film via the pressurizing elastic film and the working fluid constituting the variable focus lens unit, so that the focus of the lens can be variably controlled at high speed. An apparatus can be provided.

In the variable focal length lens device according to the present invention, the transparent elastic film constituting the variable focal length lens portion is formed of borosilicate glass or a glass mainly composed of borosilicate glass, and constitutes the variable focal length lens portion. Silicone oil or glycerin can be employed as the working fluid. Further, in the variable focus lens device according to the present invention, the main part of the heat insulating mechanism is formed of a heat insulating material made of a foamed resin, the heat insulating mechanism is an airtight structure having an air layer or a vacuum layer, or An airtight structure provided with a latent heat storage agent can be provided. In these cases, the transmission part of the input light and the output light to the variable focus optical element in the heat insulating mechanism is formed of glass or transparent resin. Also,
It is preferable to use paraffin or a fluorine compound as the latent heat storage agent.

If the heat insulating mechanism is an airtight structure having an air layer or a vacuum layer, the heat insulating effect of the heat insulating mechanism with respect to the accommodation space accommodating the variable focus optical element is enhanced, and the occurrence of the temperature drift phenomenon is further reduced. Can be suppressed. Also,
If the heat insulating mechanism is an airtight structure having a latent heat storage agent, the temperature of the housing space that houses the variable focus optical element of the heat insulating mechanism is raised for a predetermined time, the melting point of the latent heat storage agent, and the temperature within the vaporization point. It can be held, and the heat resistance of the variable focus optical element can be greatly improved.

[0012]

FIG. 1 shows a first embodiment of a varifocal lens device according to the present invention. FIG. 2 shows a varifocal lens device which constitutes the varifocal lens device. The structure and operating state of the focusing optical element are shown. The variable focus lens device includes a variable focus optical element 10 and a heat insulating mechanism 20, and the variable focus optical element 10 includes a variable focus lens unit 10a and an actuator unit 10b.

The varifocal lens portion 10a includes a glass substrate 11 having a through hole at the center, a transparent elastic film 12, an elastic film 13 for pressing, a glass spacer 14 having a through hole at the center, and a working fluid. 15. The transparent elastic film 12 is formed of a thin glass plate of borosilicate glass or the like, and is joined to one end surface of the substrate 11 with an adhesive made of an ultraviolet curable resin to form a refraction surface. The pressurizing elastic film 13 is a transparent film formed of the same glass thin plate as the transparent elastic film 12 or a film formed by joining a glass window to a stainless steel thin plate. The other end surface is joined in the same manner as the transparent elastic film 12. These substrate 11, transparent elastic film 12,
The pressurizing elastic film 13 forms a sealed space, and the working fluid 15 is sealed in the sealed space.

As the working fluid 15, silicone oil is preferably used in order to suppress the reflection of light at the interface between the transparent elastic film 12 and the elastic film 13 for pressurization. It is also preferable to use glycerin. Japanese Patent Application No. 8-290780, filed by the present applicant, includes an actuator section 10b.
The actuator unit 10b includes a plurality of plate-shaped piezoelectric deformation elements 16 and a plurality of rod-shaped piezoelectric connection elements that connect the piezoelectric deformation elements 16 on the outer peripheral side. Outer connecting member 17a, pipe-shaped inner connecting member 17b, and each piezoelectric deformation element 16
A plurality of inner peripheral joining members 17 joined to the inner peripheral edge of
c. Each piezoelectric deformation element 16 has a piezoelectric plate 16 on both surfaces of an elastic plate 16a having a through hole at the center.
This is a bimorph-type piezoelectric deformation element formed by joining b and 16c.

The actuator section 10b is connected to the variable focus lens section 10a in a state in which a fixing ring 17d fixed to one end of each outer circumference connecting member 17a is joined to the surface of the pressure elastic film 13 of the variable focus lens section 10a. In addition, one end of the inner peripheral connecting member 17b is abutted and joined to a central portion of the surface of the pressurized elastic film 13. In this state, the through-hole of the inner peripheral connecting member 17b forms an optical path for the variable focus lens unit 10a. The actuator unit 10b includes a driving unit 18, and the driving unit 18 functions to apply a voltage between the outer connecting member 17a and the inner connecting member 17b.

In the actuator section 10b, when a voltage is applied by the driving means 18, as shown in FIG. 2A or FIG.
Is deformed so that the inner peripheral connecting member 17b is
Move forward or backward with respect to a. As a result, in the varifocal lens unit 10a, the transparent elastic film 12 and the pressing elastic film 13 are deformed to change the lens characteristics and change the focal length.

Thus, in the variable focus lens device, the variable focus lens unit 10a and the actuator unit 10a
The variable focus optical element 10 made of b is adiabatically held by the heat insulating mechanism 20. The heat-insulating mechanism 20 includes a first heat-insulating window 20a, a second heat-insulating window 20b, and a heat-insulating connecting portion 20c that connects these two heat-insulating windows 20a and 20b. The cylindrical housing space is joined to each other in a liquid-tight manner, and the varifocal optical element 10 is housed in the housing space.

First heat-insulating window 20 constituting heat-insulating mechanism 20
“a” is composed of a glass substrate 21b having an airtight space 21a therein, and the space 21a is filled with dry air. The second heat-insulating window 20b, like the first heat-insulating window 20a, is made of a glass substrate 22b having an airtight space 22a therein, and the space 22a is filled with dry air. The heat-insulating connecting portion 20c has a cylindrical shape made of a foamed resin, and has a first heat-insulating window portion 20a liquid-tightly joined to one end thereof and a second heat-insulating window portion 20a to the other end.
The heat insulating window 20b is liquid-tightly joined.

In the heat insulating mechanism 20, the first heat insulating window 20
a is located opposite to one end surface of the variable focus lens unit 10 a of the variable focus optical element 10 housed in the housing space of the heat insulating mechanism 20, and the second heat insulating window 20 b is housed in the heat insulating mechanism 20. Variable focus optical element 1 housed in space
The actuator unit 10b is located opposite to the other end of the actuator unit 10b, and allows light to pass through the variable focus optical element 10.

In the varifocal lens device having such a configuration, the varifocal lens unit 10a and the actuator unit 1
The variable focus optical element 10 made of Ob
And is adiabatically held without impairing the function of the variable focus optical element 10 at all. For this reason, the occurrence of the temperature drift phenomenon in the variable focus optical element 10 can be suppressed, and the heat resistance can be greatly improved.

As described above, in the varifocal lens device, each heat insulating window 2 constituting the heat insulating mechanism 20 is provided.
Although an example is shown in which the space portions 21a and 22a of 0a and 20b are filled with dry air, the space portions 21a and 22a can be formed in a vacuum state. In this case, the heat insulating effect is higher than in the case where the space portions 21a and 22a are filled with dry air, the occurrence of the temperature drift phenomenon can be further suppressed, and the heat resistance can be further greatly improved. it can.

In the heat insulating mechanism 20, as a material for forming each of the substrates 21b and 22b constituting each of the heat insulating windows 20a and 20b, besides glass such as quartz glass, a polycarbonate material is used.
Highly transparent synthetic resins such as carbonate and polymethyl methacrylate are preferably used. In addition, the heat insulating connecting portion 20
As a material for forming c, besides a foamed resin made of polyurethane, polyphenol, polystyrene, polycarbonate or the like, a foamable polymer material such as foamed rubber is suitably used. (Second Embodiment) FIG. 3 shows a second embodiment of the varifocal lens device according to the present invention. The varifocal lens device employs the same varifocal optical element 10 as the varifocal lens device of the first embodiment, but differs from the varifocal lens device in the heat insulating mechanism 30 that adiabatically holds the varifocal optical element 10.

The heat insulating mechanism 30 includes an inner shell 30a and an outer shell 3
0b, and the inner shell 30a is composed of a pair of glass substrates 31 and 32 and a heat insulating cylinder 33 made of a heat insulating material such as a foamed resin. The constituent members 31 to 33 are joined to each other in a liquid-tight manner to form a cylindrical housing space, and
An annular recess is formed on the outer periphery of 3. The variable focus optical element 10 is housed in the housing space of the inner shell 30a.

The outer shell 30b includes a pair of glass substrates 3
4 and 35 and a heat insulating cylinder 36 made of a heat insulating material such as a foamed resin.
Numerals 6 are liquid-tightly joined to each other to form a cylindrical housing space. The heat insulating cylinder 36 is liquid-tightly joined on the inner peripheral side to the outer peripheral side of each of the substrates 31 and 32 of the inner shell 30a, and between the substrates 31 and 34 and between the substrates 32 and 35.
Disc-shaped space portions 37a and 37b are formed between them, and an annular space portion 37c is formed between both heat insulating cylinders 33 and 36. These spaces 37a to 37c are filled with dry air. In addition, you may form each space part 37a-37c in a vacuum state.

In the varifocal lens device having such a configuration, the varifocal lens unit 10a and the actuator unit 1
The variable focus optical element 10 made of Ob
And is adiabatically held without impairing the function of the variable focus optical element 10 at all. For this reason, the occurrence of the temperature drift phenomenon in the variable focus optical element 10 can be suppressed, and the heat resistance can be greatly improved.

In the varifocal lens device, however, the two space portions 37a constituting the heat insulating mechanism 30, in particular,
The disc-shaped heat insulating layer formed by the large-diameter annular space portion 37c and the circular heat insulating layer formed by the large-diameter annular space portion 37c greatly block heat from entering the housing space portion. In this case, the occurrence of the temperature drift phenomenon can be further suppressed, and the heat resistance can be further greatly improved. (Third Embodiment) FIG. 4 shows a third embodiment of the variable focus lens device according to the present invention. The varifocal lens device employs the same varifocal optical element 10 as the varifocal lens devices of the first and second embodiments,
A heat insulating mechanism 40 for adiabatically holding the variable focus optical element 10
Are different.

The heat insulating mechanism 40 includes an inner shell 40a and an outer shell 4
0b, and the inner shell portion 40a
Is composed of a pair of glass substrates 41 and 42 and a heat insulating cylinder 43 made of a heat insulating material such as a foamed resin.
These constituent members 41 to 43 are joined to each other in a liquid-tight manner to form a cylindrical housing space, a point in which the varifocal optical element 10 is housed in this housing space, and an outer shell. The part 40b includes a pair of substrates 44 and 45 made of glass.
And a heat insulating tubular body 46 made of a heat insulating material such as a foamed resin, and these constituent members 44 to 46 are liquid-tightly joined to each other to form a cylindrical housing space. Point, each space portion 47a, 47b is filled with dry air,
Alternatively, the heat insulating mechanism 3 of the varifocal lens device according to the second embodiment is different in that the heat insulating layer is formed in a vacuum state.
Similar to 0.

However, in the heat insulating mechanism 40,
The heat insulating mechanism 30 is different from the heat insulating mechanism 30 in that an annular space 47c formed by the substrates 44 and 45 and the heat insulating cylinders 43 and 46 is filled with a latent heat storage material 48. The latent heat storage material 48 imparts heat resistance to heat sterilization processing of the variable focus lens device. As the latent heat storage material 48,
A compound that undergoes a phase change from a solid phase to a liquid phase at the heat sterilization treatment temperature, or a compound that undergoes a phase change from a liquid phase to a gas phase can be employed. For example, a solid compound such as paraffin or a liquid compound such as a fluorine compound (such as Florite manufactured by 3M) is preferably used for heat sterilization of the variable focus lens device.

When the variable focal length lens device is applied to a medical optical instrument, it is heat sterilized in an autoclave. Therefore, it is important that the variable focus lens device has sufficient heat resistance to the heat sterilization temperature. is there. In this case, if the heat sterilization is performed at 135 ° C. for 5 minutes, for example, the melting point is 50 ° C.
When the latent heat storage material 48 of the degree is used, while the latent heat storage material 48 filled in the space 47c changes from a solid phase to a liquid phase, the latent heat storage material 48 has a melting point of 50 ° C. or more. Do not raise the temperature. For this reason, the accommodation space in the inner shell 40 a covered with the latent heat storage agent 48 does not rise to a temperature of 50 ° C. or more, which is the melting point of the latent heat storage agent 48, and the variable focus optical element 10
Can be greatly improved in heat resistance.

The space 47c of the latent heat storage agent 48
The amount of the heat to be supplied to the varifocal lens device in the autoclave at 135 ° C. for 5 minutes and the latent heat per unit weight of the latent heat storage agent 48 can be set.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a variable focus lens device according to an example of the present invention.

FIGS. 2A and 2B are explanatory diagrams of the operation of a variable focus optical element constituting the variable focus lens device. FIGS.

FIG. 3 is a cross-sectional view of a variable focus lens device according to another example of the present invention.

FIG. 4 is a sectional view of a varifocal lens device according to still another example of the present invention.

[Explanation of symbols]

10: Variable focus optical element, 10a: Variable focus lens unit,
10b: Actuator part, 11: Substrate, 12: Transparent elastic film, 13: Elastic film for pressurizing, 14: Spacer, 15: Working fluid, 16: Piezoelectric deformation element, 16a: Elastic plate, 16
b, 16c: piezoelectric plate, 17a: outer peripheral connecting member, 17b:
Inner circumference connecting member, 17c ... inner circumference joining member, 18 ... driving means, 20 ... heat insulating mechanism, 20a ... first heat insulating window, 20b ...
2nd heat insulation window part, 20c ... heat insulation connection part, 21a, 22a ...
Space part, 21b, 22b ... substrate, 30 ... heat insulation mechanism, 30
a: inner shell, 30b: outer shell, 31, 32: substrate, 33
... heat insulating cylinder, 34, 35 ... substrate, 36 ... heat insulating cylinder, 37
a, 37b, 37c: space, 40: heat insulation mechanism, 40a
... inner shell, 40b ... outer shell, 41, 42 ... board, 43 ...
Heat-insulating cylinder, 44, 45 ... substrate, 46 ... heat-insulating cylinder, 47
a, 47b, 47c: space portion, 48: latent heat storage agent.

Claims (10)

[Claims] 1. A varifocal lens unit whose focus changes according to a shape change of an elastic lens due to an external force, and a varifocal optical element integrally formed with the varifocal lens unit to apply an external force to the lens to apply the lens. A variable focus lens device, comprising: an actuator section that changes the shape of the lens; and a heat insulating mechanism that adiabatically holds the variable focus optical element. 2. The actuator section, comprising: a plurality of piezoelectric deformation elements formed by joining a piezoelectric plate to at least one surface of a ring-shaped elastic plate having a through hole in a central portion; An outer peripheral connecting member that connects peripheral edges in a stacked state; and an inner peripheral edge of each of the piezoelectric deformation elements that is connected in a laminated state to form an optical path to the variable focus lens section and apply an external force to the lens of the variable focus lens section. The varifocal lens device according to claim 1, wherein the varifocal lens device is constituted by: 3. The varifocal lens section comprises: a disc-shaped transparent elastic film; a pressing elastic film having a transmission portion for transmitting light at the center; and a hermetic seal formed by the transparent elastic film and the pressing elastic film. The varifocal lens device according to claim 1, further comprising: a working fluid sealed in the space. 4. The variable focus lens device according to claim 3, wherein the transparent elastic film forming the variable focus lens portion is formed of borosilicate glass or glass mainly composed of borosilicate glass. 5. The varifocal lens device according to claim 3, wherein the working fluid constituting the varifocal lens unit is silicone oil or glycerin. 6. The varifocal lens device according to claim 1, wherein the heat insulating mechanism mainly includes a heat insulating material made of a foamed resin. 7. The varifocal lens device according to claim 1, wherein the heat insulating mechanism is an airtight structure having an air layer or a vacuum layer. 8. The varifocal lens device according to claim 1, wherein the heat insulating mechanism is an airtight structure provided with a latent heat storage agent. 9. The varifocal lens device according to claim 8, wherein the latent heat storage agent is a paraffin or a fluorine compound. 10. A transmission part for input light and output light to said variable focus optical element in said heat insulating mechanism is formed of glass or transparent resin.
9. The variable focus lens device according to 7 or 8.