JPS63236479A - Exposure limiting device - Google Patents

Abstract

PURPOSE:To shorten a release time lag and to obtain a highly accurate shutter small in the number of parts by forcibly pressing the bound of the armature of an electromagnet by a fastener for engaging a shutter vane and providing a means for suppressing the bound. CONSTITUTION:When a pre-exposure for a photometry is completed, the electromagnet 5 is charged and the armature 6 kicks off the protruding part 4c of the fastener 4. The engagement of a nose vane hook 2b is disengaged, the spring engaging part 2b of the vane 2 is engaged by the hook 4d of the fastener 4 and the vane 2 is temporarily stopped. When a charging to the magnet 5 is completed, the armature 6 is restored and abuts against a position specifying member 61. The recessed part 2f is disposed between the hook parts 2b, 2c of the vane 2 and the hook 4b of the fastener 4 enters this recessed part 2f. Accordingly, the fastener 4 is further rotated counterclockwise, the protruding part 4c of the fastener 4 abuts against the armature 6, presses it, holds forcibly the armature 6 between the protruding part 6 and the member 61 to suppress the bound. Since the hook 2g is disengaged, the vane 2 is further rotated to engage with the hook 2c and douse an image pickup element 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an exposure limiting device for an electronic still camera using an image sensor such as a CCD.

[Background of the invention]

2. Description of the Related Art Electronic still cameras have been known that use an imaging device such as a CCD to record a still image signal for each field or frame on a recording medium such as a magnetic disk.

By the way, in an electronic still camera using the above-mentioned image sensor, there may be differences in sensitivity characteristics between the photometric device for obtaining exposure information and the image sensor for capturing the subject image, or there may be differences in the sensitivity characteristics of the image sensor itself. It has been difficult to provide an appropriate amount of exposure to the image sensor due to reasons such as the narrowness of the image sensor.

For example, Japanese Patent Laid-Open No. 59
-104867 or Japanese Patent Laid-Open No. 60-32484, etc. (a photograph is taken once with an image sensor under the exposure conditions obtained with a photometric element, and conditions for main exposure are set based on the image signal from the image sensor. A method has been proposed to calculate .

By the way, when taking pictures using this method, although it is possible to obtain an appropriate amount of exposure, the operation of the shutter becomes complicated. That is, at least a portion of the shutter must be opened for photometric exposure prior to the main exposure, and then the main exposure operation must be performed.

[Problem that the invention seeks to solve]

As described later, the shutter mechanism that performs the above operation is
A plurality of claws are provided on one blade, and the claws are fed each time the electromagnet is energized.

By using a displacement mechanism, it can be realized with a small number of parts.

In other words, when the first claw is fastened or locked, exposure for photometry is performed, and a pulse is sent to the electromagnet once to send it to the next claw, keeping it in a light-shielded state, and then applying a pulse to the next electromagnet. Then start the main exposure operation. At this time, it is desirable for the armature to be completely stationary in terms of exposure accuracy, but the armature moved by the first pulse comes into contact with a member that regulates its initial position and bounces. , it took a long time for the camera to come to rest, and that amount of time resulted in a release time lag. As a countermeasure to this problem, it was possible to shorten the time for the armature to settle. In other words, in order to suppress the bounce of the armature, the armature position regulating member was made of rubber or the like to damp the vibrations of the armature, thereby shortening the settling time. However, since the bounce itself cannot be eliminated, the release time lag is still long, and further improvements are needed.

[Purpose of the invention]

The present invention aims to eliminate the above-mentioned drawbacks.
The objective is to provide a high-precision shutter with a small number of parts.

[Summary of the invention]

In the present invention, in order to shorten the release time lag as much as possible, a means for suppressing the bounce by forcibly suppressing the bounce of the electromagnet armature with a tensioner that locks the shutter blade is provided. [Example 1] The figure shows the main parts of the exposure control device according to the present invention, and shows the device energized so that all exposure processes including photometric exposure can be performed.

In the figure, 1 indicates an image sensor such as a CCD,
2 indicates the shutter tip blade.

The leading blade 1 is biased clockwise by a spring 3 about a shaft 2a. Reference numeral 4 denotes a leading blade tensioner, and a spring (not shown) applies a biasing force in the direction of arrow (A) around a shaft 4a, and in the state shown in FIG. The hook portion 2b of No. 2 is engaged with the hook portion 2b of No. 2.

Reference numeral 5 designates an electromagnet for controlling the leading blade, and when a driving pulse is applied by a drive circuit (not shown), the armature 6 is attracted, and one end of the armature 6 presses the convex portion 4C of the leading blade tensioning 4. , the engagement between the hook portions 4b and 2b at the tip is released.

Reference numeral 7 designates a rear blade, to which a force is applied clockwise around a shaft 7a by a spring 8 in the same way as the leading blade 2.

Furthermore, 9 is an electromagnet for tightening the rear blade, 10 is an electromagnet for controlling the rear blade, and 11 is an armature of the electromagnet, and these 7 to 10. Since the operation is the same as 2 to 5 above, we will not explain it here.

Furthermore, in the state shown in FIG. 1, the rear blade 7 is in a position completely retracted from the optical path of the image sensor 1, and the leading blade 2 is in a position where the lower part (hatched area) la of the image sensor 1 is shielded from light. . Incidentally, such an exposure method has already been disclosed in Japanese Patent Application No. 61-2.
65893°61-265894, so the description thereof will be omitted.

12 and 13 respectively indicate aperture blades, and the shaft 12
Each can be rotated around a. Further, a biasing force is applied to the aperture blade 13 in the direction of the arrow (b) by a spring (not shown). Each aperture blade 12 and 13 has an aperture 12b, 13b and 13 corresponding to a certain aperture value.
c is provided, but in the state shown in Fig. 1, the aperture aperture 12
b is located in the photographing optical path, but the image sensor 1 is shielded from light by the aperture blades 13.

A notched gear 13a is integrally provided on the aperture blade 13, and the notched gear 13a can mesh with a notched gear 24, which will be described later. Furthermore, the aperture blade 13 has a hook portion 1.
3d to 13'' are provided and are also implanted in the pin 13.

The pin 12c installed in the aperture blade 12 is normally a leaf spring 14 for holding the aperture blade 12 in the state shown in FIG.
is in contact with.

Reference numeral 15 denotes an aperture setting lever which is biased in the direction of arrow (C) by a spring (not shown), and a hook portion 15b at one end thereof is connected to the hook portions 136 to 13g of the aperture blade 13 mentioned above, and a hook portion at the other end. 15c is capable of engaging with hook parts 13h to 13j, but in the state shown in FIG. 1, hook parts 15b and 13
d are engaged.

Reference numeral 16 indicates an electromagnet for controlling the aperture, and reference numeral 17 indicates an armature of the electromagnet.

Here, when a driving pulse is applied to the electromagnet 16, the aperture setting lever 15 is rotated counterclockwise via the pin 15d implanted in the aperture setting lever 15 by the amateur, and the hook portion 15b and the aperture blades are rotated. 13 hook portion 13.
The engagement with d is released. At this moment, the aperture blade 13 is slightly rotated in the direction of the arrow (B) by a spring force (not shown), but the hook portion 13h of the aperture blade 13 and the hook portion 15c of the aperture setting lever 15 are now engaged.

Next, at the moment when the driving pulse of the electromagnet 16 is turned off, the aperture setting lever 15 is rotated in the direction of the arrow (c) by the spring force, and the engagement between the hook portions 15c and 1.3h is released. ,
This time, hook portions 15b and 13e engage. In this phase, the diaphragm aperture 13c is located in the photographing optical path. (In this embodiment, the aperture diameter is set to 12b>13b>13c.) That is, the aperture value is set to the value of the aperture 13c.

Similarly, if driving pulses are sequentially applied to the electromagnet 16, 15b and 13f will engage, and the aperture value will be the value determined by the aperture 13b, and if 15b and 13g are engaged, the aperture blade 13 will
is withdrawn from the optical path, and the aperture is set to the value determined by the aperture 12b. When a further driving pulse is applied, the pin 13 implanted in the aperture blade 13 comes into contact with the concave end 12d of the aperture blade 12, and both aperture blades rotate in the direction of the arrow (b), leaving both out of the optical path. The aperture value becomes the open diameter.

Reference numeral 18 denotes a charge motor capable of forward and reverse rotation, and rotational force is transmitted to the gear 21.

Gears 21 and 22 form a so-called planetary clutch via an arm member 30, and when gear 21 rotates in the direction of arrow (d), gears 22 and 23 rotate, and gear 21 rotates in the direction of arrow (d). ), gears 22 and 27 mesh with each other.

Here, a case where the gear (21) rotates in the direction of arrow (d) as shown in FIG. 1 will be explained.

In this case, the rotational force of the motor 18 is the gear 21 → 22 → 11
→ 24425 will be communicated. The gear 11 is formed of a gear portion that meshes with the gear 23, a notched gear portion that meshes with the notched gear 13a provided on the aperture blade 13, and a switch drive cam portion. 19 is the gear 24 by the cam.
This is a switch that generates a signal that rotates once. When the gear 24 rotates once, the shutter blades 2 and 7 and the aperture blades 12 and 13 are charged to the state shown in FIG.

Part 1 consists of a gear portion that meshes with the gear 24 and a notch gear portion that meshes with the shutter energizing notch gear 26. When the gear 24 rotates once, the same gear also rotates once. In this case, the notched gear 26 rotates in the direction of the arrow (E).

Next, a case where the gear 21 rotates in the direction opposite to the arrow (d) will be described. In this case, the rotational force of the motor 18 is transmitted from the gear 21 to the gear 22 to the stopper. It consists of a cam part that drives the switch 20 to generate a rotated signal, and a notched meshing part that meshes with the shutter energizing notched gear 28 provided coaxially with the aforementioned notched gear 26. In this case. Since no rotational force is transmitted to the gear 23, the aperture is not energized.The rotation angle of the notched gears 26 and 28 for energizing the shutter is [26
Rotation angle] > [Rotation angle ko of 28 (.

Here, the relationship between the notch gear and the blade of the shutter energizing part will be described using FIG.

FIG. 2 shows an exploded perspective view of the notched gear portion for energizing the shutter. The appendix numbers in this figure are the same as in FIG. 1.

In the same figure, notched gears 26 and 28 and front and rear blades 2 and 7
are arranged on the same axis. 29 is a spring that applies a clockwise return force to the notched gear 26.

A shutter energizing bin 26a is formed in the notched gear 26 driven by the gear 25 described above.
extends to the vicinity of the leading blade 2 through an opening 28b provided in the notched gear 28. The leading blade 2 is provided with the shutter urging pin 26a, an engageable protrusion 2e-, and a protrusion 2f protruding toward the rear blade. The rear blade 7 is also provided with convex portions 7c and 7d,
This 7C and the aforementioned leading blade convex portion 2f can engage with each other.

On the other hand, the notched gear 2 driven by the aforementioned notched gear 1
8 is also formed with shutter energizing pins 2, 8a,
The bin 28a can engage with the arm portion 2d of the leading blade 2 and the convex portion 7d of the trailing blade 7.

Note that the phases of each member in FIG. 2 are drawn in the state shown in FIG. 1.

The operation of this configuration will be explained below.

When a photographing operation is started, an aperture value and a shutter time are calculated by a photometric calculation means (not shown).

Here, for example, assuming that the aperture value is calculated as 13b, two drive pulses Pa are applied to the aperture control electromagnet 16, and the aperture setting lever 15 is applied as described above.
The hook portion 15b of the aperture blade 13 engages with the hook portion 13f of the aperture blade 13, and the aperture aperture 13b is located in the photographing optical path. FIG. 3 shows this state. In the state shown in FIG. 3, actual exposure and readout are performed by the image sensor 1 itself at the aforementioned shutter time or at a certain determined time. During this time, a driving pulse Pb-1 is applied to the electromagnet 5 for controlling the leading blade, and as described above, the hook part 2b of the leading blade and the hook part 4b of the leading blade tensioning 4 are released, and the leading blade is imaged. The element 1 is completely shielded from light. FIG. 4 shows this situation. In this case, the hook portion 2C of the leading blade and the hook portion 4b for securing the leading blade are engaged.

Next, the shutter time is calculated again based on the output information of the image sensor 1. Based on this calculated information, drive pulses Pb-2 and Pc are sequentially applied to the leading blade control electromagnet 5 and the trailing blade control electromagnet 10, and the image sensor is now activated by the leading blade 2 and the trailing blade 7. A normal exposure is performed. This exposed image information is recorded on a recording medium (not shown). FIG. 5 shows a state in which both blades have completed running.

If it is determined that the camera is in non-continuous shooting mode,
The motor 18 rotates normally, rotates the gear 21 in the direction of arrow (d) as shown in FIG. 1, and meshes the gears 22 and 23. The aperture blades 13 are then energized by the notched gears 24 and 13a. If the aperture blade 12 is also retracted from the imaging optical path, the bottle 1 installed in the aperture blade 13
3k and one end 12e of the concave portion of the aperture blade 12, the aperture blade 12 also returns to the state shown in FIG.

On the other hand, the notch gear 26 driven by the notch gear 25 is also the first
It is rotated in the direction of the arrow (E) in the figure.

As explained in FIG. 2, when the notched gear 26 is rotationally driven, the shutter biasing pin 26a rotationally biases the leading blade through the convex portion 2e of the leading blade 2, and along with this biasing, Similarly, the trailing blade is also rotationally energized via the convex portion 2f of the leading blade 2 and the convex portion 7C of the trailing blade 7, and the state shown in FIG. 1 is again achieved. The relationship between the energization amounts at this time is shown in FIG. 6 ['a]. or,
Since the opening angle of the opening 28b (FIG. 2) of the notched gear 28 is smaller than the amount of rotation of the notched gear 26, when the notched gear 26 is energized, the notched gear 28 is also rotated in the final stage;
When 26 returns, both 26 and 28 are returned to their initial positions by the spring 29 with the open end 28c and the biasing pin 26a in contact with each other.

On the other hand, if it is determined that the camera is in a continuous shooting state at the completion of the exposure shown in FIG. 5, the motor 18 is reversed and the gear 2
1 in the opposite direction of the arrow (d) to mesh the gear 22 and l. In this case, the notched gear 28 is rotated by the notched gear portion of the gear 1, but the aperture is not energized. When the notched gear 28 is rotated, the shutter energizing pin 28
a rotates and urges both blades through the arm portion 2d of the leading blade 2 and the convex portion 7d of the trailing blade 7 (FIG. 2). At this time, the notch gear 26 is also rotated at the same time by the open end 28c of the notch gear 28 via 26a, but since the leading blade has already started to rotate with energization, there is no problem in energizing the shutter. . Further, since the notched gears 28 and 26 rotate integrally, the notched gear 28 is also returned to its original position by the spring 29.

Incidentally, the relationship between the energizing amounts at this time is shown in FIG. 6 [b]. When the above-mentioned energization is completed, the state shown in FIG. 4 is reached, and the image sensor can be exposed to light again.

If it is determined that the camera has finished continuous shooting,
By rotating the motor 18 in the normal direction, meshing the gears 22 and 23, and performing a series of charges, the state shown in FIG. 1 is restored and the next photographing including exposure for photometry can be carried out.

Next, the control related to the energization sequence described above will be explained in accordance with the flowcharts of FIGS. 8 to 11 while referring to the block diagram of FIG. 7.

In Sl of the flowchart for the eighth cap body, if the control circuit 100 reads the state of SWI 109 via the interface circuit 101 and is ON, the process advances to S2. In S2, 100 calculates the output of a photometric circuit (not shown) to determine a shutter speed (hereinafter referred to as TV) and an aperture value (hereinafter referred to as AV). Then proceed to S3, 1
10 release second stroke (SW2) state ON
Once confirmed, the process advances to the exposure routine for photometry in S4. On the other hand, if SW2 is OFF, the process returns to Sl. Here, the photometric exposure routine shown in FIG. 9 will be explained.

Exposure for photometry starts from Sll in FIG. S12
In this step, the AV value determined by photometric calculation is set. In this embodiment, there are three types of AV, so a drive pulse is sent to the mechanical drive circuit 102 via 100 to 101 for the appropriate AV, and energizes the 16 electromagnets.
Set the aperture diameter to 12b, 13c, or 13b.

In S13, an image sensor (not shown) is cleared to prepare for photometric exposure.

Since exposure starts immediately after clearing is completed, a wait is taken for the temporarily determined TV time. (S 14
) After the wait time ends in S15, 100 → 101
→ Send driving pulse 102 and energize electromagnet 5,
Run the front curtain. In this state, the shutter changes from half open to fully closed. Then, in S16, unnecessary lines are read out and necessary parts are read out.

At this time, the read video signal is integrated in a signal processing circuit 104 and read in 100. (S 1
? ) At step 100, it is determined whether or not to correct the TV based on the level of the integral value, and if correction is to be performed, the shutter speed is set to TV' and the process proceeds to the following sequence.

As a result, after completing the exposure routine for photometry, as shown in FIG.
Return to main routine.

After completing the photometric exposure in S4, the process proceeds to the main exposure in S5.

The main exposure routine will be explained with reference to FIG. S19
, a driving pulse is sent in the order of 100→101→102, energizing electromagnet 5, and leading curtain 2 runs. Then, if the shutter speed is corrected in S4, Tv' is used, and if no correction is made, the value TV is used as the shutter speed.

(S20) After the wait time ends, in S21, 100 → 10
A driving pulse is sent from 1 to 102, energizing the electromagnet 10, and the trailing curtain 7 runs.

In S22, reading from the image sensor 104 is performed, and recording is performed on the disk 106 via the magnetic recording head 105.

(S23) This completes the main exposure routine and returns to the overall routine. In FIG. 8, after completing S5, the photographing mode is confirmed in S6. At this time, the control circuit 100 reads the state of the photographing mode switch 108 via the circuit 101.

If the photographing mode is single, the process jumps to the forward charging routine of S10. Here, according to FIG. 11-A,
Explain forward charging.

In S24, 18 via 100→101→102
drive the motor in the forward rotation direction.

At this time, in S25, change the state of charge 1 switch 19 to 1.
If 00 is viewing through 101 and 19 is confirmed to be ON, 100 will be viewing 1 through 101.102.
Stop the power supply to 8. (S26) As a result, the normal rotation charging routine of S10 is ended and the process returns to S1.

If it is determined in S6 that the photographing mode is continuous, the process advances to S7 and the state of SW2 of 110 is checked.

If 110 is off, it is determined that continuous imaging is stopped, and the SIO is charged in the forward direction.

If 110 is ON, it is determined that continuous shooting is continuing, and the process proceeds to the reverse charging routine of S8. Furthermore, S7
The SW2 check in step 110 may cause chattering, so it is necessary to prevent it with a circuit or to perform S7 multiple times. Here, the reverse charging routine will be explained with reference to FIG. 11-B. 100 → in S27
18 motors are driven in the reverse direction via 101→102. At this time, in S28, 100 checks the state of charge 2 switch of 20 via 101, and
If 0 is confirmed to be ON, 100 becomes 101
, 102 to stop the power supply to 18 (S29).

As a result, the reverse charging routine of S8 is completed and S8 is completed.
Proceed to 9. In S9, 20 states are checked in the same manner as in S7. Here, if 20 is ON, the process advances to the main exposure routine of S5 in order to start the next photographing.

On the other hand, if 20 is OFF here, it is determined that the photographer has no intention of continuous photography, and the process proceeds to the normal rotation charging routine of S10 to charge the camera. This 89 SW2
It is also important to check this multiple times to prevent malfunctions.

What has been described above using FIG. 8 is the sequence of continuous and non-continuous shooting.

Hereinafter, the present invention will be explained in detail according to FIGS. 12(a) to 12(d).

FIG. 12(a) is a detailed view of the shutter leading blade 2 in FIG. 1 described above. Here, 2f is a recess between the claws 2b and 2c, and 61 is a member that regulates the initial position of the armature 6 of the electromagnet 5, and is made of a vibration-proofing material such as rubber.

Here, the reason why there is a gap between the convex part 4c of the tensioner 4 and the armature 6 is that the armature 6 is attracted by the electromagnet energization, runs idle for the gap, and has sufficient inertia, and then the armature 6 is tensioned. This is to improve the shutter release characteristics by releasing the lock between the tension 4 and the leading blade 2 at once when the tension 4 is set.

When the pre-exposure for photometry is completed in the state shown in FIG. 12(a), the electromagnet 5 is energized and the armature 6 kicks off the protrusion 40 of the tensioner 4. Then, the tensioning hook part 4b and the leading blade hook part 2b are disengaged, the leading blade 2 is rotated clockwise by the spring 3, and the hook part 4 on the other side of the tensioning 4 is then rotated clockwise.
The spring-loaded portion 2g of the leading blade 2 comes into contact with d, and as shown in FIG.
), the leading blade 2 temporarily stops.

After the electromagnet 5 is energized, the armature 4 rotates clockwise by its own energizing means (not shown) and comes into contact with the position regulating member 61. Conventionally, bounce occurred at this point and it took time for it to stabilize, but in the present invention, since the recess 2f is provided between the hook portions 2b and 2c of the leading blade, a biasing means (not shown) is provided. The hook portion 4b of the tension lever 4, which is biased counterclockwise by
From the time shown in Fig. 12(a), it further rotates counterclockwise,
As shown in FIG. 12(C), the convex portion 4c of the tension lever 4 contacts and presses the armature 6, and the armature 6 is sandwiched between the armature 6 and the position regulating member 61 to prevent it from bouncing.

Since the hook part 2g of the leading blade 2 and the tensioning lever hook part 4d are disengaged, the leading blade 2 further rotates clockwise, and the next hook part 2C and the tensioning lever hook part 4d are connected. When engaged, the image sensor 1 is shielded from light as shown in FIG. 12(d), and the sequence before the main exposure is completed.

〔effect〕

As described above, in the present invention, by forcibly holding the armature in place, the bounce caused by the armature's initial position recovery operation can be eliminated without increasing the number of parts, and the release can be prevented without increasing the number of parts. We were able to significantly shorten the time lag.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an embodiment of the present invention, showing a shutter, an aperture, and their energizing members, and shows a state in which charging is completed so that photometric exposure can be performed. Figure 2 shows an exploded perspective view of the shutter biasing section in Figure 1, and Figure 3 shows the exposure device in Figure 1 with the aperture set and exposure for photometry. Diagram showing the state. FIG. 4 is a diagram showing a state after photometric exposure has been completed and before main exposure is started, or a state in which charging by the notched gear 28 has been completed. FIG. 5 is a diagram showing a state in which the main exposure has been completed. FIG. 6 [a] is a diagram showing the amount of movement of each blade when the shutter in FIGS. 1 to 5 is energized by the notched gear 26, and FIG. 3 is a diagram showing the amount of movement of each blade when the blade is energized by a notched gear 28. FIG. FIG. 7 shows an electrical block diagram including a mechanical drive system. FIG. 8 shows the overall flowchart. FIG. 9 shows a flowchart of the photometric exposure routine. FIG. 10 shows a flowchart of the main exposure routine. FIG. 11-A shows a flowchart of the normal rotation charging routine. FIG. 11-B shows a flowchart of the reverse charging routine. FIGS. 12(a) to 12(d) are detailed views of the present invention and sequentially illustrate the operation of the leading blade up to the start of the main exposure. 1...Image sensor 2...Shutter tip blade 4...
Leading blade tensioning 5... Leading blade control electromagnet 7... Shutter rear blade 9... Trailing blade tensioning 10... Trailing blade control electromagnet 12.13... Aperture blade 15... Aperture setting lever 16... Electromagnet for aperture setting 18... Motor 21
．． 22. Plate, -E4,25,2U...Gear 26.28
... Notched gear for shutter energization 100 ... Control circuit 101 ... Interface circuit 102 ... Mechanical drive circuit 103 ... Disk drive circuit 104 ... Signal processing circuit 105 ... Recording head 106 ... Disk 107 ... Disk drive motor

Claims (1)

[Claims] A mechanism in which a member that limits exposure of an exposure control mechanism is claw-fed by energizing an electromagnet at least twice, and the tension presses and holds the armature when the electromagnet is not energized after being energized at least once. Featured exposure limiting device.