JPH1195317A - Mirror driving mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mirror driving mechanism capable of stably displacing a mirror attached to be rocked on a fixed side member at high speed with simple constitution and realizing the miniaturization of a device. SOLUTION: The main mirror 120 of a single lens reflex camera is attached to be rocked in a mirror box 110 through a pivot 116. The main mirror 120 is directly driven by the mirror driving mechanism including a linear motor 130 and rocked between a 1st position where it reflects and guides incident light from a photographing lens 200 to a finder 210 and a 2nd position where it does not prevent the incident light from the photographing lens from reaching photographic film. The motor 130 is attached to be rocked in the box 110, and the main mirror 120 is rocked through a coupling pin 128 by moving the needle 134 of the motor 130 along a stator 132.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mirror driving mechanism used in an optical apparatus such as a main mirror of a single-lens reflex camera.

[0002]

2. Description of the Related Art In a single-lens reflex camera, an optical path of light incident from a photographing lens is switched by swinging a main mirror provided in a camera body so as to be swingable. To lead to. That is, this camera has an image pickup optical path from a photographic lens attached to the front of the camera body to a film surface arranged near the back of the camera body. Also,
By arranging the main mirror in the imaging optical path at an angle of 45 ° with respect to the optical axis of the imaging lens, the imaging optical path is shielded, and the incident light from the imaging lens is reflected by the main mirror at 90 °, and the camera body Has a finder optical path leading to a finder prism mounted above.

The main mirror is swingably supported via a pivot in a mirror box defined in the camera body, is controlled to swing by a mirror driving mechanism, and has a 45 ° angle with the imaging optical path in the imaging optical path. Is retracted from the imaging optical path from the position arranged at an angle of, and swings to a position arranged in parallel with the imaging optical path. That is, when the subject is viewed through the finder, the main mirror is arranged at an angle of 45 ° in the imaging optical path, and the incident light from the photographing lens is guided to the finder side while the imaging optical path is blocked. Further, at the time of imaging, a mirror driving mechanism is operated in response to a shutter operation, the main mirror is momentarily retracted from the imaging optical path, and the imaging optical path is communicated to expose the film surface with incident light from the imaging lens.

[0004]

In a conventional motor-driven single-lens reflex camera, a mirror drive mechanism is configured to control the swing of a mirror by a combination of a rotary motor, a gear mechanism and a link mechanism. Is used. That is, the rotational motion of the motor is reduced by the gear mechanism and transmitted to the link mechanism.
The mirror is driven in the swinging direction via the link mechanism. However, in such a conventional mirror driving mechanism, since the rotational motion of the motor is indirectly transmitted to the mirror via a gear mechanism and a link mechanism,
There are disadvantages in that the number of parts is large, the configuration is complicated, and miniaturization is difficult.

SUMMARY OF THE INVENTION An object of the present invention is to provide a mirror driving mechanism capable of quickly and stably displacing a mirror used in an optical apparatus with a simple structure and reducing the size of the apparatus. .

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is to drive a mirror pivotally mounted on a fixed member to swing between a first position and a second position. The mirror driving mechanism further includes a linear actuator supported by the fixed side member including a movable element controlled to move in a linear direction, and the movable element is moved by engaging the movable element with the mirror. Thereby, the mirror is swung. Further, in the present invention, the mirror is a main mirror of a single-lens reflex camera having an imaging optical path from a photographic lens to a photographic film, the fixed side member is a member constituting a camera body of the single-lens reflex camera, The first position is a position where the main mirror intervenes in the imaging optical path and reflects incident light from the photographing lens to guide it to a finder.
The second position is a position when the main mirror is retracted from the imaging optical path.

Further, according to the present invention, the fixed member is a mirror box of the single-lens reflex camera accommodating the mirror, the slit is formed in the mirror box, and the actuator is provided on an outer surface of the mirror box. And the mirror and the mover are engaged through the slit. Further, according to the present invention, the actuator is swingably supported by the mirror box, the movable element is pivotally attached to the mirror, and an arc trajectory by the rotation of the mirror and a linear trajectory of the movable element are provided. Is absorbed by the swing displacement of the actuator.

Further, in the invention, it is preferable that the actuator is a linear motor and the mover is a mover that moves along a stator of the linear motor. Further, in the invention, it is preferable that the actuator is a solenoid plunger-type actuator, and the movable element is a plunger that is displaced by energizing a solenoid. The present invention also provides a mirror driving mechanism for driving a swingably provided mirror to swing between a first position and a second position, wherein the mirror is directly driven by a linear actuator. It is characterized by swinging.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a single-lens reflex camera will be described below. FIG. 1 is a schematic side view showing an internal structure of a camera provided with a mirror driving mechanism according to the present invention, and FIG. 2 is a schematic front view showing an assembly of a mirror box of the camera shown in FIG. FIG.
In FIG. 1, a lens mount 102 is provided on a front surface of a camera body 100 of a single-lens reflex camera, and a photographic lens 200 is attached to the lens mount 102.
Further, a finder 210 is provided at an upper part of the camera body 100.
A finder prism, an eyepiece, and the like (not shown) are arranged in the finder 210.
A mirror box 110 is disposed inside the camera body 100, and a main mirror 120 is provided in the mirror box 110. By driving and controlling the position of the main mirror 120, the optical path of the incident light from the photographing lens 200 is switched, and the incident light is transmitted to the film surface 104 disposed near the back of the camera body 100 or the finder 210 described above. To selectively lead to

That is, in this camera, the taking lens 2
00 through the mirror box 110 to the film surface 10
4 (a first image forming unit) has an imaging optical path (indicated by an arrow α in FIG. 1). Also, the main mirror 1 is located in the imaging optical path.
By arranging 20 at an angle of 45 ° with respect to the optical axis of the imaging optical path, the imaging optical path is blocked,
Incident light from the photographing lens 200 is reflected by the main mirror 120 at 90 °, and a finder screen (second imaging unit) (not shown) provided above the camera body 100.
This optical path is called a finder optical path (indicated by an arrow β in FIG. 1). The light incident on the finder screen is further refracted through the finder prism and guided to the eyepiece lens system.

A pivot 116 is provided in an upper portion of the mirror box 110 near the rear surface in a direction orthogonal to the imaging optical path and the finder optical path.
Is attached to the mirror box 110 via the pivot 116 and is swingably supported. Then, the main mirror 120 is swingably controlled by a mirror driving mechanism to be described later so as to rotate about the pivot 116, and is disposed at a first position (dashed line in FIG. 1) arranged at an angle of 45 ° with the imaging optical path in the imaging optical path. 120, a second position (indicated by a virtual line 12 in FIG. 1) that is retracted from the imaging optical path and disposed in parallel with the imaging optical path.
(Shown as 0 '). Accordingly, the first position is a position where the main mirror 120 intervenes in the imaging optical path to reflect the incident light from the photographing lens 200 and guides the light to the finder 210, while the second position is a position where the main mirror 120 performs the imaging. This is the position at the time of retreat from the optical path.

That is, when looking at a subject while looking through the viewfinder 210, the main mirror 120 is disposed at an angle of 45 ° in the imaging optical path, and the incident light from the photographing lens 200 is transmitted to the viewfinder side while the imaging optical path is blocked. To lead. Further, at the time of imaging, the mirror driving mechanism operates in response to the shutter operation, the main mirror 120 is momentarily retracted from the imaging optical path, the imaging optical path is communicated, and the film surface 104 is exposed by incident light from the imaging lens 200. . The mirror box 110 has the main mirror 12
A receiving pin 114 for receiving 0 from below at the first position is provided.

The mirror driving mechanism of the present embodiment is provided on the outer surface of the mirror box 110, and drives the main mirror 120 by a linear motor 130 as a linear type actuator to oscillate. FIG. 3 is a main part side view showing the structure of the mirror driving mechanism in this example. The linear motor 130 includes an elongated linear support member 122, a stator 132 fixedly supported on the support member 122, and a support member 122.
The mover 134 is guided upward so as to be swingable in the longitudinal direction.
And One end of the support member 122 is rotatably attached to a pivot 124 provided on the mirror box 110, whereby the linear motor 130 is swingably supported by the mirror box 110. The mover 134 of the linear motor 130 is pivotally attached to the main mirror 120 via a connection pin 128.
It is disposed so as to extend in a direction substantially along the movement locus of the connecting pin 128 when the main mirror 120 swings.

The linear motor 130 has a circular orbit of the connecting pin 128 caused by the swing of the main mirror 120,
In order to absorb the deviation generated between the movable member 134 and the linear orbit with respect to the stator 132, the main mirror 120 is freely oscillatingly displaced about the pivot 124 with the oscillating displacement of the main mirror 120. Further, the support member 122 is provided with a linear slit 126 in the longitudinal direction, and one of a pair of longitudinally extending portions on both sides defining the slit 126 is fixed to the stator 132. Is configured as

The linear motor 130 of this embodiment is configured as a so-called flat plate type linear synchronous motor.
For example, the stator 132 is configured as a secondary side, and the stator 132 is formed of a field magnet whose polarity alternates between an S pole and an N pole along a longitudinal direction, and the movable element 134 is configured as a primary side and an electric motor is formed. An armature coil 136 is provided, and a moving magnetic field is generated by controlling a current flowing through the armature coil 136. The linear motor 13
The value of 0 is not limited to the configuration described above, and may be, for example, a configuration in which the primary side and the secondary side are replaced. Alternatively, the configuration is not limited to the linear synchronous motor as described above. A linear pulse motor or the like may be used, and various methods can be adopted as long as the mover 134 can move along the stator 132.

The mirror box 110 has an arc-shaped slit 112 corresponding to an arc trajectory caused by the swing of the main mirror 120. On the other hand, the main mirror 120
Is provided with the above-mentioned connecting pin 128 at a side edge thereof. The connection pin 128 is connected to the mirror box 1
It is connected to the mover 134 through the ten slits 112 and the slit 126 of the support member 122 of the linear motor 130. Therefore, when the mover 134 and the connecting pin 128 move along the respective slits 112 and 126, the linear mirror 130 freely swings and the main mirror 120 smoothly swings and displaces.

In the camera having the above-described configuration, the main mirror 120 is directly driven and controlled by the linear movement of the movable element 134 by the operation of the linear motor 130, so that the first
Position can be displaced to the second position. Compared with the conventional configuration using a rotary motor, a gear mechanism, and a link mechanism, the power transmission efficiency can be improved with a simple configuration, and high-speed and stable. The main mirror 120 can be displaced in a short time, and the size of the apparatus can be reduced.

In the above-described configuration, the position, speed, acceleration, and the like of the main mirror 120 are calculated by calculating a drive signal supplied to the armature of the linear motor 130 and providing a position detection sensor for the main mirror 120. Since it is also possible to obtain the information of the main mirror 120, it is easy to finely control the operation of the main mirror 120 based on the information, and it is possible to perform smooth control of the main mirror 120, Reduction can be achieved.

FIG. 4 is a schematic side view showing the internal structure of a camera provided with a mirror driving mechanism according to another embodiment of the present invention, and FIG. 5 is a side view of a main part showing the structure of the mirror driving mechanism shown in FIG. FIG. The same components as those in the example shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. The mirror driving mechanism of the present example is provided with a solenoid plunger type actuator 140 as a linear type actuator.

FIG. 6 is a schematic sectional view showing the structure of a solenoid plunger type actuator 140. This solenoid plunger type actuator 140 has a solenoid box 142 in which a solenoid 144 formed of a coil formed in a cylindrical shape is arranged, and a plunger 146 is arranged in the center of the solenoid 144. Then, by energizing the solenoid 144, the solenoid plunger type actuator 140 is displaced in the axial direction. In the solenoid plunger type actuator 140 of this example, a spring (not shown) arranged in the solenoid box 142
The plunger 146 is constantly urged in a direction of being drawn into the box 142. Then, by energizing the solenoid 144, the plunger 146 is driven to protrude from the box 142 against the spring force.

The solenoid plunger type actuator 140 has a support member 152 formed integrally with a solenoid box 142. The support member 152 is a linear motor 1 in the example shown in FIG.
Similarly to the support member 122 of FIG. 30, it is swingably supported by the mirror box 1120 via the pivot 150. The tip of the plunger 146 of the solenoid plunger type actuator 140 is connected to a connection pin 158 provided on the main mirror 120 through an arc-shaped slit 156 formed in the mirror box 110. Since the stroke of the solenoid plunger type actuator 140 is smaller than that of the above-described linear motor 130, the connecting pin 158 is provided at a position close to the rotation center of the main mirror 120, and the stroke of the main mirror 120 is 45 ° with a small stroke. Rotation control is performed.

In the above-described camera, when the solenoid plunger type actuator 140 is not energized, the plunger 146 is pulled into the box 142, and the main mirror 120 is in the first position.
When the solenoid plunger type actuator 140 is energized in response to the shutter operation, the plunger 14
6 protrudes from the box 142, and the main mirror 120 is pivotally displaced to the second position. In a camera having such a configuration, the solenoid plunger type actuator 14
0, the main mirror 120 is directly driven and controlled by the linear movement of the plunger 146 caused by the operation of the first position and the second position.
Position, the power transmission efficiency can be improved with a simple configuration as compared with the conventional configuration using a rotary motor, a gear mechanism, and a link mechanism, and the main mirror 120 can be moved at high speed and stably. Can be displaced,
The size of the device can be reduced.

In the above example, the case where the mirror driving mechanism of the present invention is applied to a single-lens reflex camera has been described. However, the application of the present invention is not limited to this, and the mirror may be moved between the first position and the second position. The present invention can be applied to various optical devices that need to swing at high speed between them. In the above example, the linear motor 130 and the solenoid plunger-type actuator 140 are swingably supported, so that the arc trajectory of the connecting pin 128 caused by the swing of the main mirror 120 and the movable element 134 or the solenoid of the linear motor 130 Plunger 14 of plunger actuator 140
6 is absorbed, but instead, for example, the above-described arc is formed by a configuration in which the connecting pins 128 and 158 and the mover 134 or the plunger 146 are engaged with the elongated holes. The deviation between the trajectory and the straight trajectory may be absorbed.

[0024]

As described above, in the mirror driving device of the present invention, a linear actuator is used to drive and swing a mirror that is swingably attached to a fixed member. . Therefore, according to the present invention,
Compared to the configuration of the mirror drive mechanism using the conventional rotary motor, gear mechanism, and link mechanism, the power transmission efficiency can be improved with a simple configuration, and the mirror can be displaced at high speed and stably. The size of the optical device can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing an internal structure of a camera provided with a mirror driving mechanism according to the present invention.

FIG. 2 is a schematic front view showing an assembly of a mirror box of the camera shown in FIG.

FIG. 3 is a side view of a main part showing a structure of a mirror driving mechanism of the camera shown in FIG. 1;

FIG. 4 is a schematic side view showing the internal structure of a camera provided with a mirror driving mechanism according to another example of the present invention.

FIG. 5 is a main part side view showing the structure of the mirror driving mechanism shown in FIG. 4;

FIG. 6 is a schematic sectional view showing a structure of a solenoid plunger type actuator of the mirror driving mechanism shown in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Camera body 110 Mirror box 120 Main mirror 130 Linear motor 132 Stator 134 Mover 140 Solenoid plunger 142 Solenoid box 144 Solenoid 146 Plunger 200 Lens unit 210 Viewfinder

Claims (7)

[Claims] 1. A mirror drive mechanism for driving a mirror, which is swingably attached to a fixed member, to swing between a first position and a second position, wherein the movement is controlled to move in a linear direction. A linear actuator supported by the fixed-side member including a movable element, and the mirror is swung by moving the movable element by engaging the movable element with the mirror. Characteristic mirror drive mechanism. 2. The camera according to claim 1, wherein the mirror is a main mirror of a single-lens reflex camera having an imaging optical path from a photographic lens to a photographic film, and the fixed member is a member constituting a camera body of the single-lens reflex camera. The first position is a position where the main mirror intervenes in the imaging optical path and reflects incident light from the photographing lens to guide it to a finder, and the second position is where the main mirror retreats from the imaging optical path. 2. The mirror driving mechanism according to claim 1, wherein the mirror driving mechanism is located at the time. 3. The fixed-side member is a mirror box of the single-lens reflex camera accommodating the mirror, a slit is formed in the mirror box, and the actuator is disposed on an outer surface of the mirror box. 3. The mirror driving mechanism according to claim 2, wherein said mirror and said mover are engaged through said slit. 4. The actuator according to claim 1, wherein the actuator is swingably supported by the mirror box, the movable element is pivotally attached to the mirror, and an arc trajectory caused by the rotation of the mirror and a linear trajectory of the movable element. 4. The mirror driving mechanism according to claim 3, wherein the displacement generated between the two is absorbed by the swing displacement of the actuator. 5. The mirror driving mechanism according to claim 1, wherein the actuator is a linear motor, and the mover is a mover that moves along a stator of the linear motor. 6. The actuator according to claim 1, wherein the actuator is a solenoid plunger-type actuator, and the movable element is a plunger that is displaced by energizing a solenoid.
The mirror drive mechanism according to any one of claims 1 to 4. 7. A mirror driving mechanism for driving a swingably provided mirror to swing between a first position and a second position, wherein the mirror is directly driven by a linear actuator. A mirror drive mechanism characterized by swinging.