JP2000221563A - Camera lens protector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a driving mechanism which is suitable to miniaturize a camera lens protector. SOLUTION: The camera lens protector 0 is mounted on the leading end part of a lens barrel 1 with an image pickup lens mounted, and the protector is constituted of a pair of protecting members 5L and 5R and a driving member. The protecting members 5R and 5L are opened/closed so that the leading end part of the lens barrel 1 may be released by the members 5L and 5R at photographing, on the other hand, the leading end part of the lens barrel 1 may be covered by the members 5R and 5L and the image pickup lens may be protected at a time other than a photographing time. The driving member is connected to the protecting members 5L and 5R so as to open/close the members 5L and 5R. The driving member is constituted of shape memory alloys 6L and 6R, and the member is deformed in accordance with the power supply so as to open/close the corresponding protecting members 5L and 5R.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a camera lens protection device. More specifically, the present invention relates to a camera lens protection device using a shape memory alloy as a driving unit of a protection member that can be opened and closed with respect to a camera lens.

[0002]

2. Description of the Related Art Camera lens protection devices (barriers)
Attached to the tip of the lens barrel incorporating the imaging lens,
It comprises a protection member that can be opened and closed to protect the imaging lens by opening the front end portion during photographing and closing the front end portion other than during shooting, and a drive member that is connected to the protection member and opens and closes the protection member.
The drive member includes a manual type and an electric type. In the electric system, a motor built into the camera body and a camera lens protection device built into the tip of the lens barrel are connected by a transmission mechanism. When the main switch of the camera is turned on, the motor rotates and its power is reduced. It is transmitted to the camera lens protection device via the transmission mechanism, and opens and closes the barrier.

[0003]

When the camera lens protection device (barrier) is manually opened and closed, there is an inconvenience that a mechanical mechanism for transmitting the manual operation to the barrier becomes large. Further, in the electric system, since the power of the motor on the camera body side is transmitted to the barrier via the shaft arranged in the lens barrel, a gap is opened in the lens barrel and light may leak. In addition, there is a problem that the space efficiency is deteriorated due to the incorporation of the transmission mechanism.

[0004]

Means for Solving the Problems In order to solve the above-mentioned problems of the prior art, the following measures have been taken. That is, the camera lens protection device according to the present invention is attached to the distal end of a lens barrel incorporating an imaging lens, and basically includes a protection member and a driving member. The protection member is openable and closable in order to protect the imaging lens by opening the tip of the lens barrel during photography and closing the tip except during photography. The driving member is connected to the protection member to open and close it. As a characteristic feature, the driving member is made of a shape memory alloy and is deformed in response to an electric current to open and close the protection member. Preferably, the protection member is attached to the distal end of the lens barrel in combination of at least two,
The shape memory alloy is separately provided corresponding to each of the two protective members. Further, a base member having a lens opening corresponding to the imaging lens is attached to a distal end portion of the lens barrel, and the protection member is rotatably assembled to the base member to open and close the lens opening. Shape memory alloy is assembled to the base member around the lens opening to rotate the protection member. Further, the shape memory alloy is a wire rod, which contracts and deforms in response to energization and opens the protection member, while a spring member is engaged with the protection member, and when the energization to the shape memory alloy is released, the protection member is turned off. Close it. Alternatively, the shape memory alloy is a plate material, which is bidirectionally deformed in response to energization and directly opens and closes the protection member. Preferably, there is provided a locking member for locking the protection member in the open position in a state where the shape memory alloy is deformed in response to the energization and opens the protection member, and in a state where the energization is released. The locking member includes a shape memory alloy. When closing the protection member, the shape memory alloy is energized to release the locking of the protection member by the locking member.

According to the present invention, for example, a pair of protective members are mounted on the front end of the lens barrel so as to be opened and closed via a base member. Further, a shape memory alloy is incorporated in the base member to drive the protection member. For example, when the main switch on the camera body side is turned on, energization of the shape memory alloy is started. The shape memory alloy shrinks and deforms due to its characteristics, rotates the protective member, opens a lens opening formed in the center of the base member, and enables a photographing operation. When the power is turned off, the shape memory alloy returns to the initial position,
In response, the protection member rotates to close the lens opening and cover and protect the imaging lens.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a camera lens protection device according to an embodiment of the present invention.
FIG. 1 is a schematic plan view showing a first embodiment of a camera lens protection device according to the present invention, and shows a state where the protection device is closed. The camera lens protection device 0 is attached to the distal end of the lens barrel 1 in which an imaging lens (not shown) is incorporated, and is basically connected to the protection members 5L, 5R and the protection members 5L, 5R. And a drive member that opens and closes. As a characteristic feature, the driving member is made of the shape memory alloys 6L and 6R, and is deformed in response to the energization and is deformed by the protection member 5.
Open and close L and 5R. In the present embodiment, the protection member 5
L and 5R are attached to the distal end of the lens barrel 1 while the shape memory alloys 6L and 6R are attached to the two protective members 5 and 5R.
L and 5R are provided separately for each. In the present embodiment, a base member 3 having a lens opening 4 corresponding to an imaging lens (not shown) is mounted on the distal end of the lens barrel 1. The pair of protective members 5L and 5R are rotatably mounted on the base member 3 via shaft pins 8L and 8R for opening and closing the lens opening 4. Shape memory alloy 6L,
6R is assembled to the base member 3 around the lens opening 4 to rotate the corresponding protection members 5L and 5R, respectively. The shape memory alloy 6L is a wire, and contracts and deforms in response to energization to open the corresponding protection member 5L. On the other hand, when the spring member 7L is engaged with the protection member 5L and the energization to the shape memory alloy 6L is released, the protection member is released. Close 5L. Similarly, the shape memory alloy 6R is also a wire, and contracts and deforms in response to energization to open the corresponding protection member 5R, while the spring member 7R is engaged with the protection member 5R,
The protection member 5R is closed when the energization to is stopped.

More specifically, one protective member 5L has a substantially semicircular shape, and is rotatably attached to the base member 3 via a shaft pin 8L at its lower end. Protective member 5R
Also has a semicircular shape, and is rotatably attached to the base member 3 at the upper end thereof via a shaft pin 8R. Protective member 5L
An operating pin 9L is implanted at the lower end of the. The wire of the shape memory alloy 6L is stretched between the operation pin 9L and the terminal pin 10L implanted in the base member 3. The terminal pin 10L also serves as an electrical terminal for energizing the shape memory alloy 6L. A tension pin 1 between the operating pin 9L and the terminal pin 10L for removing slack of the shape memory alloy 6L.
2L are arranged. On the other hand, the spring member 7L is
L and a fixing pin 11L implanted in the base member 3. The spring member 7L urges the protection member 5L in the closing direction (clockwise). When the shape memory alloy 6L is energized in this state, the shape memory alloy 6L contracts and deforms, and the protection member 5L rotates counterclockwise (leftward) against the urging force of the spring member 7L, and the lens Open the opening 4. When the energization of the shape memory alloy 6L is released, the shape memory alloy 6L relaxes, so that the protection member 5L is closed in a state accelerated by the urging force of the spring member 7L. The shape memory alloy 6R and the spring member 7R connected to the other protection member 5R operate in the same manner, and the protection member 5R opens and closes the lens opening 4 in cooperation with the protection member 5L.

FIG. 2 shows the shape memory alloy 6L, shown in FIG.
It is a schematic diagram which shows the energizing operation to 6R. (A) shows an energization waveform, and (B) shows an opening state of the lens opening 4 covered with the pair of protection members 5L and 5R. When the main switch on the camera body side is turned on, energization is started and, for example, a voltage of 2 V is applied to the shape memory alloy 6 in a pulse shape.
L, 6R. The first pulse has a width of 10 ms, and heats and shrinks the shape memory alloys 6L and 6R at once, and retreats the pair of protection members 5L and 5R from the lens opening 4 to the left and right. As a result, the lens opening 4 is immediately fully opened. Thereafter, in order to maintain the fully open state, a pulse having a width of about 1 ms is intermittently applied. This allows
It is possible to save power consumption.

FIG. 3 is a schematic diagram showing another energization method. As shown in (A), the shape memory alloys 6L and 6R are energized at a voltage of, for example, about 2 V for about 10 ms at the same time when the main switch of the camera is turned on. As a result, the pair of protection members 5L and 5R are retracted left and right from the lens opening 4, and a fully opened state is obtained. Thereafter, the voltage is reduced to 0.7 V, the energization to the shape memory alloys 6L, 6R is continued, and the fully open state is maintained until the photographing of the camera ends. Power consumption can be reduced by such a stepwise energizing operation. Even when a large deformation such as plastic deformation is given to a certain kind of metal, the phenomenon of recovering the shape as if the shape before deformation is stored when heated is called a shape memory effect (SME). A metal having properties is called a shape memory alloy (SMA). SME is
This is a phenomenon associated with solid-state transformation of metal called thermoelastic martensite. In this solid state transformation, it is possible to exchange heat energy and elastic energy within a limited range. Because of the behavior similar to a cylinder containing gas, S
The MA can be considered an actuator such as a solid state Stirling engine. Ti-Ni alloys are often used because actuators can be used as polycrystals, recovery strain, fatigue characteristics, operating temperature range, safety, durability, and the like. Ti-Ni-based SMA has a relatively large electric resistance as a metal and can be easily heated by energization as described above. This means that SM
This shows that it is possible to make an actuator that can extract motion simply by connecting an electric wire to A. In particular, a linear shape memory alloy has a simple structure and shape, and is advantageous for a microactuator. The SMA can be considered to be electrically almost a resistance component, and the current may be alternating current, direct current, or pulse.
The linear shape memory alloy shrinks and deforms when energized, and when it is de-energized, cools and returns to its original state.

FIG. 4 is a schematic plan view showing a second embodiment of the camera lens protection device according to the present invention, and the protection device is in a closed state. Basically, it is the same as the first embodiment shown in FIG. 1, and corresponding portions are denoted by corresponding reference numerals to facilitate understanding. The difference is that the shape memory alloy 6L is a plate material, and is deformed bidirectionally in response to energization to directly open and close the corresponding protection member 5L. Similarly, the shape memory alloy 6R is also a plate material, and is bidirectionally deformed according to energization to directly open and close the corresponding protection member 5R. Specifically, one end of the plate-shaped shape memory alloy 6L is attached to the base member 3 via a fixing member 15L, and the other end is a pair of operating pins 16L, 16L implanted at the lower end of the protection member 5L. It is held between 17L. The plate-shaped shape memory alloy 6L warps and deforms to the left when energized, and accordingly the protection member 5L retracts to the left from the lens opening 4. When the energization is switched, the plate-shaped shape memory alloy 6L quickly returns to the initial state, and accordingly the protection member 5L moves rightward and closes the lens opening 4. Since the plate-shaped shape memory alloy 6L inherently has a spring property, the protection member 5L can be urged in the closing direction in the state shown in the drawing, thereby assuring a stable operation. The other shape memory alloy 6R functions similarly,
The corresponding protection member 5R is opened and closed with respect to the lens opening 4.

FIG. 5 schematically shows a sheet material of a shape memory alloy which can be warped and deformed in both directions by controlling the power supply.
As shown in (A), the shape memory alloy plate material 60 generates heat in response to energization and causes one of the shape memory alloy pieces 61 to be warped.
And the other shape memory alloy piece 62 that generates heat and undergoes warp deformation in response to an electric current, and an intermediate insulating layer 63 interposed between the two shape memory alloy pieces 61 and 62 that are attached to each other. Deformation in both directions occurs in response to switching of current supply to the alloy piece. (A) shows a state in which neither of the shape memory alloy pieces 61 and 62 is energized.
At this time, the laminate 60 of the shape memory alloy is in an initial state and has a flat shape. (B) shows a deformed state when one of the shape memory alloy pieces 61 is energized. The shape memory alloy plate 60 is warped and deformed in one direction. (C)
Cuts off the current to the shape memory alloy piece 61,
This shows a state in which energization to the other shape memory alloy piece 62 is started. One of the shape memory alloy pieces 61 enters a cooling process by cutting off the current, and returns to the initial state. At this time, since the other shape memory alloy piece 62 enters a heating process,
It warps and deforms in the other direction. Return direction of warpage deformation during cooling process of shape memory alloy piece 61 and other shape memory alloy piece 6
Since the directions of the warp deformations in the heat generation process 2 match, the plate member 60 of the shape memory alloy can quickly return to the initial state as a whole, the response speed can be improved, and the return spring member can be omitted.

FIG. 6 shows a third embodiment of the camera lens protection device according to the present invention, in which the protection device is closed. Basically, it is the same as the first embodiment shown in FIG. 1, and corresponding portions are denoted by corresponding reference numerals to facilitate understanding. The difference is that the locking member 20L,
20R is provided. After the shape memory alloy 6L is deformed in response to energization and opens the protection member 5L, the locking member 20L locks the protection member 5L in an open position in a state where the energization is released. Similarly, the other locking member 20R locks the protection member 5R in the open position after the shape memory alloy 6R is deformed in response to the energization and opens the protection member 5R, and then in a state where the energization is released. Preferably, the locking member 20L includes an additional shape memory alloy 22L, and when closing the protection member 5L, the additional shape memory alloy 22L is energized to lock the locking member 2L.
The locking of the protection member 5L by 0L is released. Similarly, a release shape memory alloy 22R is connected to the other locking member 20R. The locking member 20L is rotatable around a shaft pin 21L implanted in the base member 3,
It is urged by a spring member 25L in a direction opposite to the shape memory alloy 22L. In the illustrated state, the locking member 20L hits the hit pin 24L. Similarly, the other locking member 20R is also rotatable about the shaft pin 21R, the spring member 25R is engaged, and the hitting pin 24R is hit.

FIG. 7 is a schematic plan view showing the opened state of the camera lens protection device shown in FIG. As shown in the figure, when the shape memory alloy 6L contracts due to energization, the protection member 5L rotates counterclockwise (leftward) about the shaft pin 8L and retracts from the lens opening 4. As a result, the lens opening 4 is opened. At this time, the lower end of the protection member 5L rides over the locking member 20L and is locked at the tip. As a result, even if the energization to the shape memory alloy 6L is cut off, the protection member 5L is kept at the open position, thereby saving power consumption. In order to close the protection member 5L after the photographing operation, the additional shape memory alloy 22L is first energized to release the locking by the locking member 20L, and the locking member 20L is turned clockwise (rightward). Move. As a result, the engagement between the tip of the locking member 20L and the lower end of the protection member 5L is released. Accordingly, the protection member 5L rotates clockwise (rightward) about the shaft pin 8L according to the urging force of the spring member 7L, and shields the left half of the lens opening 4. Similarly, the other protective member 5R operates to open and close the right half of the lens opening 4.

[0014]

As described above, according to the present invention,
Attached to the tip of the lens barrel incorporating the imaging lens,
A protective member that can be opened and closed to protect the imaging lens by closing the distal end of the lens barrel except for photographing while opening the distal end of the lens barrel during photography, and a driving member that is connected to the protective member and opens and closes it. The driving member is made of a shape memory alloy and is deformed in response to an electric current to open and close the protection member. By adopting a shape memory alloy as the driving member and attaching it to the distal end of the lens barrel together with the protective member, a more compact mounting than before becomes possible.

[Brief description of the drawings]

FIG. 1 is a plan view showing a first embodiment of a camera lens protection device according to the present invention.

FIG. 2 is a waveform chart for explaining the operation of the camera lens protection device shown in FIG.

FIG. 3 is a waveform chart for explaining the operation of the camera lens protection device shown in FIG. 1;

FIG. 4 is a plan view showing a second embodiment of the camera lens protection device according to the present invention.

FIG. 5 is a cross-sectional view for explaining the operation of a shape memory alloy plate incorporated in the camera lens protection device shown in FIG. 4;

FIG. 6 is a plan view showing a third embodiment of the camera lens protection device according to the present invention.

FIG. 7 is a plan view showing a third embodiment of the camera lens protection device according to the present invention.

[Explanation of symbols]

0: Camera lens protection device, 1: Lens barrel, 3
..Base member, 4 ... Lens opening, 5L ... Protective member, 5R ... Protective member, 6L ... Shape memory alloy,
6R: Shape memory alloy, 7L: Spring member, 7R
..Spring member, 20L: locking member, 20R: locking member, 22L: shape memory alloy, 22R: shape memory alloy

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nobuyoshi Inoue 2- 18-10 Shimura, Itabashi-ku, Tokyo Inside Copal Corporation (72) Inventor Tohru Eguro 2- 18-10 Shimura, Itabashi-ku, Tokyo Stock Association Inside Copal Corporation (72) Inventor Shinji Ito 2-18-10 Shimura, Itabashi-ku, Tokyo Co., Ltd. Inside Copal Corporation (72) Inventor Kenichi Watanabe 2-18-10 Shimura, Itabashi-ku Tokyo, Japan Copal Inside F Term (reference) 2H083 CC24 CC28

Claims (7)

[Claims] 1. Attached to the distal end of a lens barrel incorporating an imaging lens, which can be opened and closed to protect the imaging lens by closing the distal end except during photographing while opening the distal end during photographing. A lens protection device for a camera comprising a protective member and a driving member connected to the protective member to open and close the protective member, wherein the driving member is made of a shape memory alloy and is deformed in response to an electric current to open and close the protective member. A lens protection device for a camera. 2. The method according to claim 1, wherein at least two of the protective members are combined and attached to the distal end of the lens barrel, and the shape memory alloy is separately provided for each of the two protective members. The camera lens protection device according to claim 1. 3. A base member having a lens opening corresponding to the imaging lens is mounted on a distal end portion of the lens barrel, and the protection member is rotatably assembled to the base member to open and close the lens opening. 2. The camera lens protection device according to claim 1, wherein the shape alloy is assembled to the base member around the lens opening to rotate the protection member. 4. The shape memory alloy is a wire and contracts and deforms in response to energization to open the protection member, while a spring member is engaged with the protection member and the shape memory alloy is released when the energization to the shape memory alloy is released. 2. The camera lens protection device according to claim 1, wherein the protection member is closed. 5. The camera lens protection device according to claim 1, wherein the shape memory alloy is a plate material, and is deformed bidirectionally in response to an electric current to directly open and close the protection member. 6. A locking member for locking the protection member at an open position in a state where the shape memory alloy is deformed in response to the energization and opens the protection member, and after the energization is released. The camera lens protection device according to claim 1, wherein 7. The locking member includes a shape memory alloy, and when closing the protection member, energizes the shape memory alloy to release the locking of the protection member by the locking member. 7. The camera lens protection device according to claim 6, wherein: