JPS63101835A - Mirror control device for single-lens reflex camera - Google Patents

Abstract

PURPOSE:To prevent an exposure from being given carelessly to a film, by controlling an operation of a mirror driving mechanism by referring to a signal from a switching means for executing a switching operation by an initial operation at the time of removing a photographic lens. CONSTITUTION:At the time of removing a lens unit, first of all, a release lever 40 which is provided on a hook 7 is slid to the right, and a switch 42 is turned off to the first stage of a slide operation. The moment an OFF-signal of the switch 42 is inputted to a body MPU60, a mirror controlling circuit 61 is operated, and by a motor 28 and a mirror driving mechanism 30, a mirror 27 and a light shielding plate 31 are moved to a descent position. At an instant that the switch 42 is turned off, the lens unit is not removed yet from a lens board. Accordingly, when the light shielding plate 31 is moved to the descent position, the moment the switch 42 is turned off, even if the removing operation of the lens unit is executed continuously, the film 11 can be prevented exactly from being exposed to an external light.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a lens shutter type single-lens reflex camera with interchangeable lenses. ).

[Conventional technology]

Lenssha Nta-2 is known as a single-lens reflex camera with a large screen size aimed at commercial photographers and semi-professionals. Generally, this type of single-lens reflex camera consists of a camera body and a magazine that stores film and a photographic lens with a built-in shutter that is attached to the camera body. Some cameras can be linked together to allow you to take pictures with added tilt.

The body of a single-lens reflex camera is provided with a mirror that opens a photographing optical path when raised, closes the photographing optical path when lowered, and simultaneously forms a finder optical path. Furthermore, in the above-mentioned single-lens reflex camera, the camera body is equipped with a light-shielding plate that rises and falls in conjunction with the mirror in order to completely close the photographing optical path when the mirror is lowered. is normal.

By the way, in a -eye reflex camera, the mirror rapidly moves to the raised position just before exposure is started, so vibrations at this time may become a problem, especially when demanding depiction conditions are required. Additionally, special photography lenses with long flange backs may not be able to be attached to the camera body because the mirror gets in the way. To solve this problem, a mirror-up device is known in which the mirror can be moved and held at a raised position by manual operation, apart from the normal photographing sequence.

[Problem that the invention seeks to solve]

However, when attempting to provide the above-mentioned mirror up device in a lens shutter type single-lens reflex camera, the following problems arise. In other words, in this type of single-lens reflex camera, the shutter is built into the photographic lens that can be attached to and removed from the camera body, so it is not possible to raise the mirror and light shielding plate with the photographic lens removed, or to raise the mirror and light shielding plate. If an attempt is made to remove the photographic lens while the photographic lens is still in place, external light will enter the camera body through the opening of the mounting portion of the photographic lens, and the film will be exposed to this light.

In order to solve this problem, for example, the light shielding plate that is moved behind the mirror can be made smaller and operated by a drive system separate from the mirror. This requires an additional drive system, which complicates the structure and is disadvantageous in terms of cost.

The present invention has been made in view of the above-mentioned prior art, and provides a mirror control device that prevents inadvertent exposure of the film while providing a mirror up device in a lens shutter type eye reflex camera. The purpose is to provide

[Means for solving problems]

In order to achieve the above object, the present invention transmits signals from both a mirror-up operation means operated when performing a mirror-up operation and a switching means operated by an initial operation when removing a photographic lens from a camera body. The reference is made to control the operation of the mirror drive mechanism.

When the switching means is operated via the mirror up operation means and the mirror drive mechanism when the mirror and the light shielding plate are respectively in the raised position, that is, in the state where the photographing optical path is open, the mirror is driven. By activating the mechanism in an emergency manner, each of the mirror and the light blocking plate is moved to a lowered position, that is, a position where the photographing optical path is blocked.

Furthermore, in a preferred embodiment of the present invention, the switching means is configured to maintain the switching operation state unless a photographic lens is attached to the camera body, and when the photographic lens is not attached, Even if the mirror up operation means is operated, the operation of the mirror drive mechanism is prohibited, and the mirror and the light shielding plate are maintained at the lowered position. Further, a motor is used to move the mirror and the light shielding plate between the raised position and the lowered position, and these movements can be easily performed by electrically controlling the drive of the motor. It has become.

Embodiments of the present invention will be described below with reference to the drawings.

〔Example〕

In FIG. 1, which schematically shows a lens shutter type eye reflex camera using the present invention, a pair of guide tubes 3 are provided protruding forward from a camera body 2. A feeding unit 4 is attached. This feeding unit 4 is provided with a lens board 6 to which a bellows 5 is connected. The lens unit 8 is attached to the lens board 6 in a light-tight manner by means of a hook 7 provided on the upper part of the lens board 6. A knob 9 provided at the base of the feeding unit 4
When the lens unit 8 is rotated, the lens unit 8 moves forward and backward in the optical axis direction together with the lens board 6, thereby enabling focus adjustment. Further, a magazine 12 in which a film 11 is stored is attached to the back side of the camera body 2.

In addition to the projection lens 13, the lens unit 8 includes a shutter blade 14 and a shutter control circuit 15 for controlling the drive thereof. It has a built-in shank blade drive mechanism 16 (Fig. 1). By attaching the lens unit 8 to the lens board 6, the electrodes (
(not shown) is connected, and the lens unit 8 and camera body 2 are also electrically connected via a flexible cord 17.

On the other hand, when the magazine 12 is also attached to the camera body 2, the two are electrically connected via the contacts 18. The magazine 12 includes a film winding motor 20, a winding control circuit 21 (FIG. 1) for controlling its drive, and a winding drive mechanism 22, and these operations are controlled by electrical signals from the camera body 2. It looks like this. Magazine 12 to camera body 2
In order to prevent the film 11 from being exposed to external light when removed from the magazine 12, a light shielding M25 that can be pulled out and inserted is provided on the front surface of the magazine 12. In addition,
A liquid crystal display panel 23 is provided on the top surface of the magazine 12, and is used to display the number of films and warnings.

The camera body 2 is provided with a mirror 27 that is movable between a lowered position shown by a solid line and a raised position shown by a two-dot chain line. The mirror 27 is driven by a motor 28 for driving the mirror.
and a mirror control circuit 29 (Fig. 1) that controls its drive.
, is operated by the mirror drive mechanism 30. This mirror drive mechanism 30 also operates a light shielding plate 31 that is movably provided behind the mirror 27. The light shielding plate 31 functions to close an opening 32 formed on the back surface of the camera body 2 and prevent light from entering the magazine 12 side.

When the mirror 27 is in the lowered position, the opening 32 is completely closed, and when the mirror 27 is moved to the raised position, it is moved up in conjunction with this, and the opening 32 is completely opened. The operation of the mirror 27 and the light shielding plate 31 is carried out by the operation of the release button 33.
In addition to being controlled in accordance with the mirror-up position, it can also be manually moved to the raised position by operating the mirror-up button 34. Of course, in this case as well, the motor 28. The mirror drive mechanism 30 is now activated.

As shown in FIGS. 2 and 3, the hook 7 for attaching the lens unit 8 is pivoted to the lens board 6, and is attached by a spring 38 in the counterclockwise direction, that is, in the direction in which the lens unit 8 is attached. Forced. Then, by engaging the lower part of the lens unit 8 with a support hook (not shown) protruding from the lower part of the lens board 6, and inserting the tip of the hook 7 into a locking hole 8a formed in the lens unit 8. The lens unit 8 is tightly attached to the lens board 6. In this engaged state, the release lever 40 slidably provided on the hook 7 is moved to the left by the bias of the spring 41, and the distal end hook 40a touches the stepped portion 6a formed on the lens board 6. Since they are engaged, the hook 7 is prevented from moving in the release direction. Further, when the release lever 40 is moved to the illustrated position, the switch 42 is turned on.

When removing the lens unit 8, first slide the release lever 40 to the right and release the tip hook 40a and the stepped portion 6.
Release the engagement with a. Thereafter, by lifting the hook 7 as shown in FIG. 3, the lens unit 8 can be removed. In addition, at the beginning of the removal operation of the lens unit 8, the release lever 40 is slid as described above, but at this time the switch 42 is turned to OFF.
Since the lens unit 8 is turned off, by monitoring the signal from the switch 42, it is possible to detect a preparatory operation before the lens unit 8 is actually removed.

When the hook 7 is lifted to the position shown in FIG. 3, the lens attachment detection lever 43 provided on the lens board 6 is rotated by the bias of the spring 44, and its tip 43a protrudes from the mount surface 45. As a result, the pin 47 implanted in the lens attachment detection lever 43 also moves.

Therefore, even if the lifting of the hook 7 is subsequently released, the tip of the pin 47 supports the bottom surface of the hook 7.
The hook 7 is held in the position shown in FIG. Also, at this time, the tip hook 40a of the release lever 40 is attached to the stepped portion 6.
Since it comes into contact with a, the switch 42 is turned off.
The condition remains.

When attaching the lens unit 8, as described above, the lower side of the lens unit 8 is first engaged with the lens board 6, and then the lens unit 8 is pushed into the lens board 6. As a result, the flange rear surface 48 of the lens unit 8 presses the tip 43a of the lens attachment detection lever 43 protruding from the mount surface 45. Then, when the lens attachment detection lever 43 rotates against the spring 44 and the tip of the pin 47 comes directly below the fitting hole 49 formed on the bottom surface of the hook 7, the hook 7 is rotated to the left by the spring 38. The lens unit 8 is now tightly attached to the lens board 6.

An exposure frame 50 is formed on the front surface of the magazine 12, as shown in FIG. Then, the light shielding lid 25 can be inserted into the magazine 12 so that the exposure frame 50 can be completely shielded. In order to detect insertion and withdrawal of the light-shielding lid 25, switches 52 and 53 are built into the magazine 12. When the light shielding M25 is completely inserted, the switch 52 is set to 0FFL, and conversely, when the light shielding lid 25 is completely pulled out, the switch 52 is set to 0FFL.
3 turns OFF.

In FIG. 5, which shows the circuit configuration used in the above camera, block A shows the part built into the camera body 2, block B shows the part built into the lens unit 8, and block C shows the part built into the magazine 12. Blocks B and C represent contacts 18.
It is electrically connected to block A via 55. Block A is a microprocessor unit (hereinafter referred to as body MPU) 60. It includes a mirror control circuit 61 for controlling the operation of the mirror drive motor 28, an up operation detection circuit 62 for detecting that the mirror up button 34 has been operated, and a buzzer 63 for alarm. and the body MPU
60 sends and receives electrical signals to and from blocks B and C, executes sequences necessary for photographing, and monitors whether each part is operating normally.

Block B includes a shutter control circuit 15, which controls driving of a motor 64 for operating a shutter blade drive mechanism 16. Also,
ON/O by the release lever 40 provided on the hook 7
A signal from the switch 42 that is turned OFF is input to the body MPU 60 via the connector 55.

Block C is a microprocessor unit (hereinafter referred to as magazine MP) that controls electrical signals on the magazine 12 side.
65 and the winding control circuit 21, a liquid crystal driver 66 for driving the liquid crystal display panel 23, a light shielding lid detection circuit 68 for detecting the presence or absence of the light shielding lid 25 via the switches 52 and 52, and a film The signal from the infrared stage/receiver detects the reflection on the surface of the film 11.
It includes a film detection circuit 69 for detecting the presence or absence of the film.

According to the above configuration, a normal photographing sequence is performed as follows. First, in the viewfinder observation state shown in FIG. The light shielding plate 31 is placed in the lowered position, and the shutter blade 14 is open. Therefore, the subject light flux that has passed through the photographic lens 13 is reflected by the mirror 27 and formed into an image on the focusing glass 35. When the operation of the release button 33 is detected by the body MPU 60, a closing signal is input from the body MPU 60 to the shutter control circuit 15, the motor 64 is driven, and the shutter blade 14 is closed. This shutter blade 14
When the closing signal is fed back to the body MPU 60, the motor 28 is driven via the mirror control circuit 61, and the mirror drive mechanism 30 is operated to raise the mirror 27 and the light shielding plate 31, respectively, and retreat from the photographing optical path.

Thus mirror 27. When it is confirmed that the light shielding plate 31 has moved to the raised position, the body MPU 60 outputs an exposure start signal to the shutter control circuit 15. As a result, motor 6
4. Shutter blade 1 via shutter blade drive mechanism 16
4 opens and closes to perform exposure. When the exposure is completed, an exposure completion signal is fed back from the shack control circuit 15 to the body MPU 60. Upon receiving this exposure end signal, the body MPU 60 outputs a film winding signal to the magazine MPU 65.

When a film winding signal is input to the magazine MPU 65, the motor 20 is driven by the winding control circuit 21, and the film 11 is wound through the winding drive circuit 22. When the film 11 has been wound by exactly one frame, a winding completion signal is returned to the magazine MPU 65, and the operation of the winding control circuit 21 is stopped. The winding completion signal is body M
When input to the PU 60, the motor 28 is reversed by the mirror control circuit 61, and the mirror 27. The light shielding plate 31 moves to the lowered position. When it is detected that these have reached the fully lowered position, the body MPU 60 operates the shutter control circuit 15 to open the shutter blade 14 again. As a result, the -th photographing sequence is completed and the viewfinder observation state shown in FIG. 1 is restored.

By the way, in the above-mentioned normal viewfinder observation state, that is, in the finder observation state during shooting, the light shielding plate 31 is in the lowered position and completely shields the aperture 32, so even if the lens unit 8 is removed, the film cannot be seen. 1
Since the lens unit 1 will not be exposed to light, the lens unit 8 can be replaced at will. In addition, when moving the mirror 27 and the light shielding plate 31 to the raised position with the lens unit 8 attached, press the mirror up button 34.
All you have to do is operate.

The up operation detection circuit 62 detects that the mirror up switch 72 is turned on by operating the mirror up button 34.
When detected, a shutter close signal is first output from the body MPU 60 to the shutter control circuit 15. and,
When the shutter blade 14 is completely closed, this closing completion signal is fed back to the body MPU 60, and upon receiving this signal, the mirror control circuit 61 is activated, and the mirror 27 and the light shielding plate 31 are moved to the raised position. It becomes like this. Therefore, in this case, since the light is blocked by the shutter blade 14, the film 11 is not exposed. Then, from this state, the mirror up button 34 is returned to the normal position, and the mirror up switch 72 is turned OFF.
In this case, contrary to the mirror-up operation, the shank blade 14 is opened after the mirror 27 and the light-shielding plate 31 have reliably returned to the lowered position.

Furthermore, in the camera configured as described above, even if an inadvertent operation is performed as described below, the process shown in Figure 6 that is performed after the power is turned on, and the process that is performed subsequently. By the process shown in FIG. 7, accidents such as the film 11 being exposed to external light can be completely prevented.

In the initial state when the power switch is turned on, the mirror 27.degree. light-shielding plate 31 is placed in the lowered position by the power-off processing described later. After the power is turned on, if the lens unit 8 is removed from the lens board 6 in order to replace it, for example, the removal can be done using the switch 4.
Detected by 2. Then, the light-shielding lid detection circuit 68 detects that the light-shielding lid 25 is pulled out,
Further, when the film detection circuit 69 detects that the film 11 is loaded, the body MPU 60 causes the mirror control circuit 61 to control the mirror 27 even if the operation of the mirror up button 34 is detected, as shown in step 75. A signal for raising the mirror 27 and the light shielding plate 31 are not outputted, but instead the buzzer 63 sounds and the liquid crystal display panel 23 displays a warning, and the mirror 27 and the light shielding plate 31 maintain the lowered state.

In other words, if the mirror is raised when the lens unit 8 is removed, the film 11 will be directly exposed to external light, so in such a case, the mirror-up operation is prohibited and a warning is issued if such an operation is attempted. will be carried out.

Note that when the light-shielding lid detection circuit 68 detects that the light-shielding lid 25 is completely inserted into the magazine 12,
Alternatively, when the film 11 is not detected by the film detection circuit 69, the mirror 27 and the light-shielding plate 31 can be freely raised and lowered by operating the mirror up button 34, regardless of whether the lens unit 8 is attached or not. Also, by operating the mirror up button 34, the mirror 27. When the power switch of the camera is turned off with the light shielding plate 31 raised, the hold on the power is cut off after the mirror 27 and the light shielding plate 31 are lowered. Therefore, in the initial state when the power switch is turned on, each of the mirror 27 and the light shielding plate 31 always maintains a lowered state.

While the power switch is maintained in the ON state, the processing shown in FIG. 7 continues to be executed. According to this process, when a mirror-up operation at the time of removing the lens unit 8 is detected in step 76, the operation is prohibited and a warning is issued, as described above. Furthermore, mirror 27. Step 7 indicates that the lens removal operation was started when the light shielding plate 31 was in the raised position.
When detected by 7, press the mirror up button 3
Even if mirror 27.4 is set to the mirror up operation position, mirror 27. The light shielding plate 31 is brought into an emergency down operation.

That is, when removing the lens unit 8, the release lever 40 provided on the hook 7 is first slid to the right, and at the beginning of the sliding operation, the switch 42 is
is turned off. The moment the OFF signal of this switch 42 is input to the body MPU 60, the mirror control circuit 61 is activated, and the motor 28. The mirror 27° light shielding plate 31 is moved to the lowered position by the mirror drive mechanism 30. At the moment when the switch 42 is set to 0FFI, the lens unit 8 has not yet been removed from the lens board 6.

Therefore, the moment the switch 42 reaches 0FFt, the light is blocked by F.
By moving the i31 to the lowered position, even if the removal operation of the lens unit 8 is continued, the film 11 can be reliably prevented from being exposed to external light. . Note that the above emergency down operation is not performed when the light-shielding lid 25 is inserted or the film 11 is not loaded. Also, the 6th
Step 75 in the diagram. When the processes from steps 76 to 77 in FIG. 7 are performed, these processes are performed in consideration of the fact that the operation position of the mirror up button 34 and the positions of the mirror 27 and the light shielding plate 31 conflict with each other and become unnatural. When this is done, use an electromagnet to press the mirror up button 3.
It is desirable to forcibly return 4 to the normal position.

〔Effect of the invention〕

As described above, according to the mirror control device of the present invention, even if the operation for removing the photographic lens is started while the mirror and the light shielding plate remain raised, the mirror and the light shielding plate are instantly removed by the initial operation. Since it automatically returns to the lowered position, even if the photographic lens is removed, accidents such as the film being exposed to outside light can be reliably prevented. Moreover, in achieving such a function, there is no need to complicate the mirror drive mechanism or to separately drive the light shielding plate, making it extremely useful as a safety device for lens shutter type eye reflex cameras.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the structure of a camera using the present invention. FIG. 2 is a sectional view of the main part of the hook for attaching the lens with the lens unit attached. FIG. 3 is a sectional view of the main part of the hook for attaching the lens with the lens unit removed. FIG. 4 is a partially cutaway view schematically showing the structure of the front side of the magazine. FIG. 5 is a block diagram showing the circuit configuration used in the present invention. FIG. 6 is a flowchart showing a process for prohibiting the mirror and the light shielding plate from moving to the raised position. FIG. 7 is a flowchart showing the process for urgently moving the mirror and the light shielding plate to the lowered position when the lens unit is removed. 2... Camera body 7... Hook 8... Lens unit 12... Magazine 25... Light shielding lid 27... Mirror 31... Light shielding plate 34... Mirror up button 40... Release lever 42... Switch 43... Lens attachment detection lever.

Claims (3)

[Claims] (1) A mirror is moved between the finder observation position and the photographing position, and as the mirror moves, a light shielding plate is installed between the optical path blocking position, which blocks the photographing optical path, and the optical path opening position, which opens the photographing optical path. A camera equipped with a camera body having a built-in mirror drive mechanism for moving the camera, and a photographing lens having a built-in shutter and detachably connected to the camera body, wherein the mirror and the light shielding plate are moved through the mirror drive mechanism. A mirror-up operation means operated to move each lens to a photographing position and an optical path opening means, and a switching means operated to switch when an initial operation for removing the photographic lens from the camera body is performed. When the initial operation is detected by the switching means when each of the mirror and the light shielding plate is in the photographing position and the optical path open position, the mirror and the light shielding plate are set to the viewfinder regardless of the operation of the mirror up operation means. A mirror control device for a single-lens reflex camera, characterized in that the mirror drive mechanism is operated to forcibly move the mirror to an observation position and an optical path blocking position. (2) The switching means is configured to maintain the switching operation state when the photographic lens is not attached to the camera body, and when the mirror-up operation means is operated in this switching state, the switching means Mirror control for a single-lens reflex camera according to claim 1, characterized in that the operation of the mirror drive mechanism is prohibited so that the mirror and the light shielding plate are maintained at the finder observation position and the optical path blocking position, respectively. Device. (3) A warning display is provided when the operation of the mirror drive mechanism is prohibited regardless of the operation of the mirror-up operation means.
A mirror control device for a single-lens reflex camera as described in .