JP2572034B2 - camera - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a camera having a single-lens reflex finder configuration.

More specifically, the present invention relates to a mirror in which a total reflection mirror placed in a photographing optical path is retracted outside the optical path during photographing, and returns to an original position again after photographing by preliminary exposure and main exposure. And a camera having the same.

[Prior Art] As is conventionally known, in a single-lens reflex camera having a total reflection mirror in the viewfinder optical path, the total reflection mirror retracts during photographing, and returns to the photographing optical path again after photographing. A mechanism is required. In order to perform such an operation in a short time, driving by a spring (spring) is generally performed.

In a generally known silver halide camera, a manual winding mechanism for feeding the film or an automatic winding mechanism using a motor is incorporated, and a spring for retracting the mirror is charged in conjunction with the winding of the film. I have. Then, the mirror return clutch is disengaged and the winding stop is released by the operating force of the rear curtain of the shutter or by the rotation of another motor.

[Problems to be Solved by the Invention] However, when film winding is not necessary, for example, in an electronic camera using a video floppy disk, a spring for driving a mirror cannot be charged by a film winding mechanism. .

In addition, the aperture size of the electronic camera is about 1/4 that of a normal 35mm camera, so the drive of the rear curtain of the small shutter for the electronic camera releases the mirror return clutch and the winding stop. That is virtually impossible.

Further, providing a release magnet is also not advantageous because extra space is required.

Therefore, an object of the present invention is to provide a camera having a retracting / returning mechanism for a reflecting mirror, which is suitable for an electronic camera or the like.

[Means for Solving the Problems] An imaging means for imaging an incident light image, a shutter means for exposing the imaging means, and a first direction and a second A drive motor that rotates forward and backward with respect to the direction, a mirror locking unit that locks a reflection mirror that guides the incident light image to the viewfinder in the middle of a shooting optical path, and a rotation of the drive motor in the first direction. A mirror retracting means for releasing the lock by the mirror locking means in conjunction with the mirror retracting means and retracting the reflection mirror out of the photographing optical path; and a retracting operation of the reflecting mirror out of the photographing optical path by the mirror retracting means. Shutter control means for performing the first exposure by operating the shutter means in conjunction therewith, and causing the shutter means to perform the second exposure based on the exposure amount correction information obtained by the first exposure. The mirror locking means returns the reflection mirror to the middle of the photographing optical path in accordance with the rotation of the drive motor in the second direction after the second exposure, and locks the reflection mirror. It is characterized in that it is kept.

[Operation] When a release operation is performed on the shutter means, the drive motor rotates in the first direction, the lock by the mirror locking means is released, and the mirror retreating means retracts the reflection mirror out of the imaging optical path.

The shutter control unit operates the shutter unit in conjunction with the retreat operation of the reflection mirror to the outside of the photographing optical path by the mirror retreat unit, and performs the first exposure on the imaging unit. Then, based on the exposure amount correction information obtained by the first exposure, the shutter control means operates the shutter means to perform the second exposure on the imaging means.

After the end of the second exposure, the drive motor rotates in the second direction opposite to the first direction to return the reflection mirror to the middle of the photographing optical path. Locked on the way.

EXAMPLES Hereinafter, the present invention will be described in detail based on examples.

FIG. 1 is a diagram showing mechanical components of an electronic camera to which the present invention is applied. In this figure, 1 is a step motor, 2 is an aperture signal sector gear, 3 is an aperture signal lever, 4 is a spring (tensile spring), 5 is a bell crank, 6 is an aperture drive ring, 7 is an aperture blade, 8 is a cam ring, 9 Is a spring (tensile spring), 10 is an automatic squeezing lever, 11 is a spring (tensile spring), 12 is a DC (direct current) motor, 13 is a bevel gear, 14 is a quick return clutch cam, 15 is a stop cam, and 16 is a charge cam. , 17 is a release lever, 18 is a release slide plate, 19 is a spring (tensile spring), 20 and 21 are shafts, 22 is a first tightening member, 23 is a spring (tensile spring), 24 is an energy storage lever, and 25 is a clutch. , 26 is a spring (tension spring), 27 is a quick return lever, 28 is a mirror holding lever, 29 is a mirror, 30 is a contact lever, and 31 is a clutch. Interlocking lever, 32 is a spring (tension spring), 33 is an intermediate lever, 34 is a stop lever, 35 is a spring (tension spring), 36 is a stop switch, 37 is a mirror retract spring, 38 is a mirror return spring, 39 is a crystal filter, 40 is a shutter rear blade, 41 is a spring (tensile spring), 42 is a shutter front blade, 43 is a spring (tensile spring), 44 and 45 are shutter driving coils, and 46 and 47 are coils 44 and 45. A permanent magnet for generating an electromagnetic force in opposition to the shutter, 48 is a shutter tightening member, 49 is a spring (tensile spring), 50 is a pin, 51 is an image sensor such as a CCD, 52 is a spring, 53 is an aperture, and 54 is an aperture. The second tightening member, 55 is a spring, 56 is a restraining member (second tightening member presser), and 57 is a spring (tensile spring).

FIG. 1 is a perspective view showing a state immediately before pressing a release button (not shown). The retreating and returning operations of the total reflection mirror 29 will be briefly described with reference to the timing chart shown in FIG.

First, when a release button (not shown) is depressed at the first stage (first stroke), a photometric circuit (not shown) is activated, and the step motor 1 is rotated according to the output. As a result, the aperture signal sector gear 2 is rotated, and the aperture signal lever 3 is rotated against the spring 4. Thus, the cam surface 3a
(Corresponding to the aperture amount) is set.

The step motor 1 controls the position of the cam surface 3a so as to always follow the output of the photometric circuit and to obtain an appropriate aperture value while the first-step release button is pressed.

When the release button is further depressed and reaches the second-step depressed position, the start switch of the camera (described in detail below:
3) is closed, and the DC motor 12 rotates counterclockwise (reverse rotation). As a result, the charge cam 16 is rotated clockwise, and the release lever 17 is pushed down. Then, the release slide plate guided by the shafts 20 and 21
18 begins to descend.

The cam surface 18a of the release slide plate 18 is
Then, the first tightening member 22 is turned clockwise to release the locking of the energy storage lever 24. Therefore, the energy-storing lever 24 is pulled right by the spring 37 and turns the quick return lever 27 clockwise via the clutch 25.

Since the pin 27b attached to the quick return lever 27 is engaged with the engaging portion 28a of the mirror holding lever 28, the mirror holding lever 27
28 turns clockwise, and retracts the mirror 29 out of the optical path. At this time, the tip 24a of the energy storage lever 24 comes into contact with the winding stop lever 34, so that the lever 34 is turned counterclockwise to
Evacuate from.

Further, since the tip member 27c of the quick return lever 27 pushes down the automatic iris lever 10 against the spring 11, the aperture drive ring 6, which has been prevented from rotating by the action of the spring 11, until the clock 9 is rotated by the force of the spring 9. Direction, and the bell crank 5 is turned left. At this time, since the cam surface 3a of the aperture signal lever 3 is set at a position corresponding to the output of the photometric circuit as described above, the bell crank 5 rotates until the pin 5a is suppressed by the cam surface 3a. I do. In other words, the amount of rotation of the aperture drive ring 6 is controlled by the pin 5b.

Along with the clockwise rotation of the aperture drive ring 6, the pin 7b of the aperture blade 7
Slides along the cam surface 8a of the cam ring 8 and is stopped down to a predetermined aperture value. In this figure, for convenience,
Although only one diaphragm blade is illustrated, it goes without saying that a diaphragm mechanism is constituted by a plurality of diaphragm blades.

In this way, in response to the depression of the release button, the reflection mirror 29 retreats out of the optical path, and the aperture is stopped down to an appropriate value. Thereafter, due to the electromagnetic force acting between the coil 44 and the permanent magnets 46 and 47, the shutter rear blade 40 turns left against the spring 41, and the tip portion 40a of the rear blade 40 is attached to the protrusion 48a of the shutter tightening member 48. Locked. Thereafter, the energization of the coil 44 is stopped, and the preliminary exposure is performed using the image sensor 51 for a predetermined shutter time.

After that, check whether the exposure amount was appropriate,
The set shutter time or the aperture amount is corrected in accordance with the amount deviating from the appropriate amount.

Next, the drive coil 45 of the leading blade 42 is energized, and the spring 43
Counterclockwise turns the front blade 42. Then, at the same time when the leading blade 42 reaches the position covering the aperture 53, the leading end 42a
As a result, the cam portion 48b of the shutter tightening member 48 is pressed down, whereby the shutter tightening member 48 is turned leftward against the spring 49. Thus, the locking of the rear blade 40 is released. At this time, since the energy storage lever 24 has already turned clockwise (the mirror is in the retracted state), and the restraining member 56 has also turned counterclockwise, the hook portion 54a of the second tightening member 54 can lock the shutter tightening member 48. It is in a state. Therefore, the shutter tightening member 48 is
Locked by the tightening member 54, the locking of the rear blade 40 is released.

Thereafter, by cutting off the current to the drive coil 45 provided on the leading blade 42, the leading blade
Run 42. Then, after a lapse of the corrected predetermined shutter time, the power supply to the drive coil 44 provided on the rear blade 40 is stopped, and the rear blade 40 is caused to travel by the spring 41. Thus, the exposure by the shutter blade is completed.

The above description is the operation sequence from when the release button is pressed to when the shutter runs. Thereafter, when the DC motor 12 is rotated clockwise (forward rotation), the quick return clutch cam 14 rotates counterclockwise, so that the clutch 25 is rotated counterclockwise via the communication lever 30 and the clutch interlocking lever 31. As a result, the engagement between the clutch 25 and the quick return lever 27 is released, so that the quick return lever 27 is turned leftward by the force of a spring 38 (mirror return spring), and the mirror 29 fixed to the mirror holding lever 28 is disengaged. Return to the viewfinder optical path. At this time, the operation of the spring 11 also returns the automatic aperture lever 10 to the original position, and returns the aperture drive ring 6 to the open position. Therefore, the aperture is open.

Also, at this time, since the winding stop lever 34 is pressed by the energy storage lever 24 and retreats from the winding stop cam 15, the clockwise rotation (forward rotation) of the DC motor 12 is not prevented.

Thus, the spring 37 (mirror retract spring) of the energy storage lever 24 is charged via the intermediate lever 33 by the counterclockwise rotation (forward rotation) of the charge cam 16. Then, the energy storage lever 24 is locked by the first tightening member 22,
Clutch 25 is again pin 27a of quick return lever 27
Engages. At this time, the second tightening member 54 is counterclockwise turned against the spring 55 (away from the shutter tightening member 48).

Thereafter, the rotation of the motor 12 is stopped by the stop lever 34 preventing the stop cam 15 from rotating counterclockwise.

FIG. 3 is an electrical block diagram for controlling the present embodiment shown in FIG. In this figure, reference numerals 36 and 51 denote the anti-winding switch and the image sensor shown in FIG. 1, 201 a control circuit, 202 an SSG (synchronous signal generator), 203 an image sensor driving circuit, 204 a signal processing circuit, 205 is a shutter time setting circuit, 206 is a shutter control circuit, 207 and 208 are excitation circuits, 209 is a correction circuit, 210 is an aperture value determination circuit, 211 is a photometric element, 212 is a step motor drive circuit, and 213 is a DC motor drive Circuit.

FIG. 4 is a flowchart showing a control procedure to be executed by the control circuit 201 shown in FIG.

Hereinafter, a control procedure in the present embodiment will be described with reference to FIGS. 3 and 4.

First, when the first switch 214 is closed by pressing the release button in the first stage (step S1 in FIG. 4), the control circuit 201
Activates the image sensor drive circuit 203 and the aperture value determination circuit 210 (step S2 in FIG. 4). As a result, the drive of the image sensor 51 is started in synchronization with the timing signal from the SSG (synchronous signal generator) 202, while the aperture value determination circuit 210 uses the object brightness information Bv from the photometric element 211 and the shutter time setting. An appropriate aperture value Av is determined based on the shutter time information Tv from the circuit 205 and output to the step motor drive circuit 212. Then, the step motor drive circuit 212 drives the step motor 1 and sets the aperture signal lever 3 to the aperture value.
Adjust to the rotation angle position corresponding to Av.

Then, the control circuit 201, the stop and wait for a certain period of time t ₁ required for preset operation (Fig. 4 step S3), and thereafter, the second to be turned on in the second stage depression of the release button
Check if switch 215 is closed (fourth
Figure Step S4A). As a result, if step 215 is closed, the control circuit 201 causes the aperture value determination circuit 210 to store the aperture value Av at that time (step S4 in FIG. 4).
B) Then, the DC motor drive circuit 213 is instructed to rotate the DC motor 12 in the counterclockwise direction (forward rotation: see FIG. 1) (step S5 in FIG. 4). Thus, the mirror 29 is retracted, the aperture is narrowed down, and the like.

On the other hand, during this time, the control circuit 201
It is checked whether or not (see FIG. 1) has been turned off (step S6 in FIG. 4), and the retraction of the mirror 29 and the narrowing of the aperture blade 7 are completed, and the counterclockwise rotation of the winding stop lever 34 (the energy storage lever 24) Switch by pressing down)
When the switch 36 is turned off, the operation output of the DC motor drive circuit 213 is stopped to stop the rotation of the DC motor 12 (step in FIG. 4).
S7).

Then, the control circuit 201 performs the energization over time t ₂ to the rear blade coil 44 instructs the trailing blade coil excitation circuit 207 (FIG. 4 step S8), and stops the subsequent energization (Fourth
Figure Step S9). The conduction period t ₂ is the time sufficient to rear blade 40 is captured by the shutter clamping member 48 and left-handed. Thus, the aperture 53 is in an open state, and the control circuit 201 activates the correction circuit 209 at this time (the fourth state).
Figure Step S10).

In this state, the aperture blade 7 is first operated by the aperture value determination circuit 210.
Accordingly, the correction circuit 209 determines an appropriate shutter time based on the level of the luminance signal Y from the signal processing circuit 204 in the actual aperture state, and determines this as a correction signal. Shutter time setting circuit 20 as
Output to 5. This allows the shutter time setting circuit 2
05 replaces the initially set shutter time (by manual operation or the like) with the shutter time from the correction circuit 209.

Control circuit 201 after step S10, in such operation waits sufficient predetermined period t ₃ (FIG. 4 step S11A), and stores the output at that time to the correction circuit 209 (Fig. 4 step S11
B). Next, the coils 44, 4 are supplied to the coil excitation circuits 207, 208.
5 is energized (step S12 in FIG. 4). As a result, the leading blade 42 turns left and the aperture 53 is closed, and both blades 40 and 42 maintain this state by the action of electromagnetic force while resisting the respective springs 41 and 43 (the shutter tightening member 48 is Locked by the second tightening member 54).

Next, the control circuit 201 triggers the shutter control circuit 206 (FIG. 4, step S13). As a result, the shutter control circuit 206 responds to the vertical synchronization signal (Vd) from the SSG 202 immediately after the trigger, and
Stop supplying power to Thus, the leading blade 42 runs. Thereafter, the previously corrected shutter time obtained from the shutter time setting circuit 205 is counted, and at that time, the excitation circuit 207 is operated to stop energizing the rear blade coil 44. As a result, the rear blade 40 travels.

The proper exposure of the image sensor 51 is performed in this manner, and the image information formed by this exposure is read out in synchronization with the next vertical synchronization signal Vd, and processed by the signal processing circuit 204. Then, it is recorded on a magnetic disk or the like as a so-called one-field television signal.

Thereafter, when the first switch 214 is turned off (step S14 in FIG. 3), the control circuit 201 stops the operation of the circuits 202, 209 and 210 (step S15 in FIG. 4), and the DC motor drive circuit 213
, The DC motor 12 is rotated (forward rotation) clockwise (CW) (step S16 in FIG. 4). Thereby, the resetting of the mechanical system is performed. Then, when the switch 36 is turned on (Step S17 in FIG. 4) when the tip of the stop lever 34 enters the recess of the stop cam at the time of completion of the reset, the control circuit 201 activates the DC motor drive circuit 213. Stop.

Although the embodiments described so far are examples in which the present invention is applied to an electronic camera, it is needless to say that the present invention can also be applied to a single-lens reflex camera using a normal film.

[Effects of the Invention] As described above, according to the present invention, the return mechanism of the reflection mirror can be formed by using the forward rotation and the reverse rotation of one motor, so that the camera is simple and compact. Can be obtained.

Further, even in an electronic camera that does not have a film winding mechanism such as a camera using a silver halide film, charging and operation of members related to a series of photographing operations, including retreating and returning operations of a reflecting mirror, can be performed with good timing. It can be carried out.

Particularly, in an electronic camera that electronically captures an image by an imaging unit, not only the retracting and returning operations of the reflecting mirror with a single drive motor, but also a preliminary exposure for correcting a photometric value and a main exposure for performing actual photographing. It is possible to realize a shooting sequence unique to an electronic camera using an image sensor having a narrower dynamic range than a silver halide film with a simple configuration.

[Brief description of the drawings]

FIG. 1 is an exploded view showing an embodiment of a camera to which the present invention is applied, FIG. 2 is a timing chart showing a schematic operation of FIG. 1, and FIG. 3 is a block diagram showing an electric control system of the present embodiment. FIG. 4 is a flowchart showing an example of a control procedure to be executed by the control circuit shown in FIG. 12… DC motor, 14… Quick return clutch cam, 15… Cushion cam, 16… Charge cam, 17…
Release lever, 22 ... First tightening member, 24 ... Energy storage lever, 25 ... Clutch, 27 ... Quick return lever,
29 …… Mirror.

Continued on the front page (72) Inventor Yoshitaka Murata 770 Shimonoge, Takatsu-ku, Kawasaki Canon Inc. (72) Inventor Yukio Ogawa 770 Shimonoge, Takatsu-ku, Kawasaki Canon Inc. Tamagawa Office (56) References Kaisho 56-175826 (JP, U)

Claims (1)

(57) [Claims] 1. An image pickup means for picking up an incident light image, a shutter means for exposing the image pickup means, and a forward / reverse rotation in a first direction and a second direction with a release operation on the shutter means. A driving motor, a mirror locking means for locking a reflection mirror for guiding the incident light image to a finder in the middle of a photographing optical path, and interlocking with the rotation of the driving motor in the first direction. Mirror retraction means for releasing the locking by the mirror locking means and retreating the reflection mirror out of the photographing optical path; and interlocking with the retraction operation of the reflection mirror out of the photographing optical path by the mirror retreating means, Shutter control means for causing the shutter means to perform a first exposure by operating the means and performing a second exposure based on the exposure amount correction information obtained by the first exposure; The locking means is for returning the reflection mirror to the middle of the photographing optical path and locking the reflection mirror in conjunction with the rotation of the drive motor in the second direction after the second exposure. A camera characterized in that: