JPS63316835A - Camera - Google Patents

Abstract

PURPOSE:To smoothly and rapidly executing the return of an actuator to an initial state by using a cooling fan interlocking with winding and rapidly executing the cooling of the actuator made of shape memory alloy. CONSTITUTION:By operating a release button, a current is applied to the wire- shaped actuator 8 made of the shape memory alloy, which contracts at temp. >=transformation temp. When a lens barrel 10 and a slit plate 14 move, which is detected by a photocoupler 15, the application of the current is stopped and at the same time a shutter is actuated. When the completion of the action of the shutter is detected, a motor 1 for winding a film rotates and a cooling fan 7a also rotates, so that the actuator 8 is rapidly cooled. And the lens barrel 10 moves in a B direction by means of a spring 13. Since cooling is rapidly executed by the fan 7a, a shift to a pulling state where the actuator 8 is plastically deformed is smoothly executed. Thus, the return of the actuator to the initial state can be smoothly and rapidly executed with a simple mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention relates to a camera, and more specifically, a shape memory alloy that is deformed to restore a memorized shape by heat is used to move a lens barrel for focus switching. The present invention relates to a camera having such an actuator.

(Background of the Invention) Conventionally, when a shape memory alloy is energized to generate heat, it takes a very quick time to restore the memory shape (for example, shrink). Various proposals have been made to configure .

However, shape memory alloys have the following problems, making it difficult to use cameras with actuators constructed using them.

(1) Restoration to the memory shape is quick at temperatures above the transformation temperature, but
After turning off the electricity to generate heat, it takes a long time for plastic deformation to occur due to external force (spring force, etc.).

(2) In order to improve the problem in (1) above, if an external force such as spring pressure is made to act strongly on the non-palm,
The resistance during restoration (for example, contraction) to the memorized shape due to heat becomes large, causing problems such as slowing down the speed of contraction and reducing the amount of displacement.

(Object of the Invention) The present invention has been made from the above-mentioned viewpoints, and its purpose is to solve the above-mentioned conventional problems when constructing an actuator using a shape memory alloy, and to utilize the shape memory alloy. Therefore, it is an object of the present invention to provide a camera having an actuator that is suitable for high-speed snapshots.

(Summary of the Invention) The camera according to the present invention, which has been made to achieve the above object, is characterized in that it is supported movably in the direction of the photographing optical axis for focusing, and that the camera is movably supported in the direction of the photographing optical axis for focusing. a lens barrel to which a biasing force is applied in a direction; an actuator for moving the lens barrel in the other direction of the optical axis against the biasing force; and a rotational driving force of a motor for winding the film. In a camera equipped with a film winding device, the actuator is made of a shape memory alloy that restores its memorized shape when the temperature is raised above the transformation temperature by a connected energization control device, and the actuator is made of a shape memory alloy that restores its memorized shape when the temperature is raised above the transformation temperature by a connected energization control device. The lens barrel is plastically deformed in response to the applied biasing force to allow the Sa of the lens barrel to move in one direction of the optical axis, and when the temperature rises, the lens barrel is restored to the memorized shape to move the lens barrel in the other direction of the optical axis. The actuator is provided with a cooling fan for applying cooling air to the actuator, and a cooling fan is provided in conjunction with the rotation mechanism of the film winding device.

In the above configuration, the rotation mechanism of the film winding device refers to a mechanism that uses the rotation of a motor to automatically wind the film by one shooting screen for each shooting operation, such as a control circuit built into the camera. To exemplify a known winding mechanism in which a film winding shaft is rotated via a gear train by rotational drive of a motor when the end of a series of photographing operations such as release and shutter scanning is detected according to drive control by Can be done. The cooling fan described above may be operated in conjunction with either the motor or the gear of the film winding mechanism, and it is particularly preferable to select and use a cooling fan located close to the actuator.

In the actuator of the present invention, the actuator is configured using a shape memory alloy, for example, when a spring force as an external force acts on the shape memory alloy that memorizes the shape of the coil when it is wound in a direction to pull the coil. At room temperature, the coil is plastically deformed and stretched by the spring force, and when necessary, the coil is energized to raise the temperature above the transformation temperature to restore the memorized shape. It can be configured as

Examples of shape memory alloys having the above properties that can be used in the camera of the present invention include titanium-nickel alloys.

(Example of the invention) The present invention will be described below based on embodiments shown in the drawings.

FIG. 1 and FIG. 2 show an embodiment of the present invention,
In this figure, 1 is a motor for driving film winding; 2 is a motor for driving film winding;
is a pinion attached to the output shaft of the motor 1, and 3 to 6 are gears forming a gear train that transmits rotational force for film winding. It is configured to operate, transmit the rotational force from the pinion 2 to a winding mechanism (not shown), wind the film by a predetermined amount, and then stop.

Reference numeral 7a denotes a fan coaxially supported by the gear 4, and as this gear rotates, the fan 7a also rotates to constitute the cooling device 7 for blowing air, which will be described in detail later.

Reference numeral 8 denotes a wire-like actuator made of a shape memory alloy, which is stretched across a fixed part 9a of the camera body and one arm part 10a of the lens barrel 10, and is shaped like a straight wire as shown in FIG. (the state deformed by the compression spring force described later) returns to the preset memorized shape (in this example, a coiled shape with a shortened tension length) when the predetermined temperature is reached. It is designed to be deformable. Note that 8a and 8b are energization lead wires for supplying electric power for heat generation to the actuator, and are connected to an energization control device (not shown).

Reference numeral 10 denotes a lens barrel, which has arm parts 10a and 10b, one end of a wire-shaped actuator made of a shape memory alloy is fixed to one arm part 10a as described above, and the other arm part 10b. A fixed shaft 12 passes through the lens barrel 10, and the lens barrel 10 is supported so as to be slidable back and forth along the shaft 12.

The shaft 12 is fixedly installed across the fixed parts 11a and llb of the camera body, and a compression spring 13 is wound around the shaft 12 between the fixed part 11a and the arm part 10b of the lens barrel. is inserted so as to constantly bias the lens barrel 10 toward the fixed portion 11b.

A slit plate 14 is fixed to the lens barrel 10. A photocoupler 15 is fixed to a main body fixing part (not shown), and these are arranged so that the slit plate 14 extends between the light emitting and receiving light paths of the photocoupler 15. Therefore, the amount of movement of the lens barrel 10 can be detected in accordance with the number of times the slit plate 14 blocks the optical path for light transmission and reception. Note that the configuration of the circuit for this detection is similar to the known one, so detailed explanation thereof will be omitted here.

Reference numeral 20 denotes a wall provided around the fan 7a, and is provided to allow air to efficiently act on the wire-shaped actuator 8. Therefore, it is desirable that this wall 2o forms an arc shape along the fan. . Note that the reference numeral 21 in the figure indicates the direction of the wind.

Next, the operation of this example device will be explained.

1. In order to take a picture with the camera, a release button (not shown) is pressed down to the first stage position (SWI), whereby a correction measurement section (not shown) operates and the position of the lens is determined within the circuit.

2. Next, by pressing the release button to the second position (5W2), the above 1. According to the signal, the wire-like actuator 8 made of a shape memory alloy is energized.

3. The energized wire-like actuator 8 generates heat,
Shrinkage begins when the temperature rises above the transformation temperature.

4. 3 above. As the wire-like actuator 8 contracts, the lens barrel 10 moves in the direction shown in the figure.

5. The slit plate 14 is also moved by the movement of the lens mirror 810, and the above 1. When it is counted and detected via the photocoupler that the lens barrel has moved by the amount of movement determined by , the power to the wire-shaped actuator 8 is cut off.

6. At the same time as the above-mentioned energization is stopped, a shutter operation is performed and the film is exposed.

7. When a shutter completion signal is detected by a detection means (not shown), the film winding motor starts rotating, the film is wound, and the cooling fan starts rotating. , the wire-shaped actuator 8 is cooled. Therefore, the wire-like actuator 8 is rapidly cooled down.

8. As the wire-shaped actuator 8 is cooled, it gradually begins to extend due to the spring force applied to the lens barrel, and the lens barrel can move in the direction B in the figure. Permissible.

Since the cooling at this time is quickly performed by a cooling fan, the wire-like actuator 8 is smoothly brought into the plastically deformed tensile state in the sixth row.

9. When the winding is completed and the lens barrel returns to the initial position (the state shown in FIG. 1), the camera enters the initial state and is ready for the next photograph.

In order to provide the above operation, a shape memory alloy (N
An example is a case where T alloy (manufactured by Furukawa Electric Co., Ltd.) is used.

Physical properties change depending on humidity Mechanical properties I * Change depending on the difference between operating temperature and transformation point! As explained above, the camera with the AF mechanism of the present invention has the following characteristics:
Since the actuator made of a shape memory alloy is quickly cooled by a cooling fan that rotates in conjunction with the winding, the actuator can be returned to its initial state smoothly and quickly when the shooting operation button is pressed. Compared to the case where a motor or the like dedicated to the AF mechanism is used, the device can be configured mechanically more simply and at a lower cost, and since a motor or the like dedicated to the cooling device is not required, there is also the advantage that the above-mentioned effects are further enhanced.

[Brief explanation of drawings]

Figure 1 is a diagram showing an overview of the configuration of a lens barrel drive device for a camera configured according to the present invention, and Figure 2 is a diagram showing a wire-shaped actuator formed using a shape memory alloy and a cooling device. It is a figure explaining a relationship. 1: Drive motor for film winding 2: Pinion 3, 4, 5, 6: Winding gear train 7: Cooling device 7a: Fan 8: Wire-shaped actuators 8a, 8b: Lead wire 9: Camera body fixing part 10: Lens barrel 10a, 10b: Arm portion 11
a, llb: Shaft support fixing part 12: Shaft 13: Compression spring 14 Nislit plate 15: Photocoupler 20: Fan surrounding wall

Claims (1)

[Claims] A lens barrel that is movably supported in the direction of the photographing optical axis for focusing and is biased in one direction of the optical axis; In a camera equipped with an actuator that moves the optical axis in the other direction, and a film winding device that uses the rotational driving force of a motor to wind the film, the actuator is raised to a temperature above the transformation temperature by a connected energization control device. Using a shape memory alloy that restores its memorized shape when heated, it is plastically deformed under the urging force acting on the lens barrel at room temperature, allowing the lens barrel to move in one direction along the optical axis. When the temperature rises, the lens barrel is moved in the other direction of the optical axis by restoring to the memorized shape, and a cooling fan that applies cooling air to this actuator is interlocked and connected to the rotation mechanism of the film winding device. A camera characterized in that it is provided with: