JPH0792579B2 - Imaging device - Google Patents

Description

The present invention relates to an image pickup device, and more particularly to an image pickup device having a light shielding means such as a shutter.

<Prior Art> Conventionally, when performing exposure control of an image pickup apparatus, a highly accurate photometric circuit is required because the latitude of the image pickup element used in the apparatus is very narrow.

Therefore, a light receiving element dedicated to photometry is provided separately from the image sensor,
Based on the exit of the element, the light receiving state of the image pickup element is once controlled by, for example, driving a shutter, a diaphragm, etc., and the output of the image pickup element is taken out under such control,
A technique for controlling so as to readjust the light receiving state based on such an output is known, for example, in Japanese Patent Laid-Open No. 59-194574.

<Problems to be Solved by the Invention> However, even when the conventional method is used, for example, when a normal person is photographed in the outside world during the daytime, the output of the image pickup device is, for example, the light amount of a bright portion such as the sky. Since it contains a large amount, it is dark for a person and there is a problem that it is underexposed as a whole.

Such a problem has been a problem that can commonly occur in devices that process the output of the image sensor other than photometry. The present invention aims to solve such problems.

Another object of the present invention is to provide a novel light shielding method for an image sensor in view of the above problems.

<Means for Solving Problems> In order to achieve the above-mentioned object, an image pickup apparatus of the present invention includes an image pickup device and a first light-shielding surface of the image pickup device, which is stopped first.
And the second state of stopping the light-shielding only part of the light-receiving surface
And a light-shielding means having the above condition.

<Operation> In the above configuration, by using the output of the image sensor in the second state in which only a part of the light receiving surface is shielded from light, it is possible to prevent the light amount of a bright portion such as the sky from being affected.

〔Example〕

 Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

First, the mechanical structure of the embodiment of the present invention will be described.

FIG. 1 is a perspective view of a diaphragm device and a shutter device according to an embodiment of the present invention. In FIG. 1, 1 is a CCD as an image sensor, 2 is an optical axis, 3 is a diaphragm device, and 4 is a shutter. The figure shows an initial state before photographing. That is, the light flux incident on the image sensor 1 along the optical axis 2 is shielded by the diaphragm plate 30 and is imaged by a part of the front blade 41 of the focal plane shutter having the front blade 41 and the rear blade 51. About 30% of the lower part of the element 1 is shielded.

The rectangular diaphragm plate 30 has a longitudinally cut out groove at the top.
The groove 30M has locking portions 30a to 30d and an inclined portion 30M.
e ~ 30g is formed. In the lower part, the groove 30M
On the straight line parallel to, the throttle holes 30B to 30D are formed at positions corresponding to the locking portions 30b to 30d, respectively. In addition,
The diaphragm plate 30 is biased rightward (in the direction of arrow M) by a coil spring 30S that is hooked at the right end, and moves along a guide mechanism or the like (not shown). The diaphragm device will be further described with reference to FIG. FIG. 2 is a plan view of the diaphragm device. In the figure, 31 is a locking claw, the tip of which forms a hook 31f that engages with the groove 30M, is rotatable about a shaft 31j, and is biased counterclockwise by a coil spring 31S. ing.

32 is an L-shaped armature that has an L-shaped longitudinal section and has an outwardly bent hook portion 32f that is rotatable about a shaft 32j and is a leaf spring that abuts the yoke 33y of the magnet 33. 32b is welded and is urged clockwise by the leaf spring 32b. (See FIG. 2) Next, the shutter device 4 will be further described with reference to FIG. FIG. 3 is a front view showing the tightening release and displacement amount limiting device 40 for the leading blade 41. In FIG. 3, 41a and 41b are projections for regulating the position of the leading blade 41, which are provided on the holding portion 41H of the blade 41. Has been. 41S is a coil spring, which is hooked on the holding portion 41H so as to apply a turning force to the leading blade 41 in the clockwise direction in the drawing.
4 is a locking member that is biased by a coil spring 44S so as to rotate clockwise around a shaft 44j.
A hook 44f is formed so as to be locked to the protrusion 41a or 41b. Further, 44S is a stopper that restricts the clockwise rotation of the locking member 44.

42 is an armature that has a substantially flat plate shape and is rotatable around a shaft 42j. The yoke 43 of the magnet 43 is
A leaf spring 42b abutting against y is welded and is urged counterclockwise by the leaf spring 42b.

Further, the tightening release and displacement amount control device 50 for the rear blades 51.
Has almost the same structure as the front blade 41 except that the projection 41b is removed. The rear blade 51, the coil spring 51S, the locking member 54, the coil spring 54S, the stopper 54S, and the armature 5
2, consisting of magnet 53 and so on. (See FIG. 1) Next, the operation will be described.

First, when a release (not shown) is pressed, pre-exposure is performed by a light receiving element (not shown) or the like, and a temporary aperture diameter is selected.

The diaphragm plate 30 in this embodiment is provided with diaphragm holes 30B to 30D having three kinds of diaphragm diameters, and the diaphragm diameter selected in the pre-exposure is any one of the diaphragm holes 30B to 30D. is there.

Therefore, the operation of the diaphragm plate 30 will be described with reference to FIG.

At present, as shown in FIG. 2, the hook portion 31f of the locking claw 31 has the narrowed portion 3f.
It is locked to the upper locking portion 30a, and in this state, the image sensor 1 is shielded from light. Assuming that the aperture hole 30B is selected in the previous photometry, the magnet 33 is given one electrical pulse. Therefore, the magnet 33 attracts the armature part 32a of the armature part 32 against the elasticity of the coil spring 32b, so that the armature part 32 rotates counterclockwise and its key part.
Since 32f presses the base end 31k of the locking claw 31 and rotates the locking claw 31 clockwise against the tension of the coil spring 31S, the hook 31f is shown by the z-dot chain line from the locking part 30a. Thus, the diaphragm plate 30 moves in the direction of the arrow M by the coil spring 30S, and the hook portion 31f abuts the slant portion 30e in the groove 30M. While the armature (32) is being sucked by the magnet (33), the locking claw (31) cannot return to its original state, so the hook part (31f) has a slanted part (3).
When the contact with 0e is earlier than the return of the armature 32, the diaphragm plate 30 is stopped in the contact state. afterwards,
If the attraction force of the magnet 33 is lost and the armature 32 returns, or if the contact is slower than the return of the armature 32, the hook 31f contacts the slant 30e and returns to the original state, Stopper plate 3 is newly locked with the next locking part 30b.
Stop 0. Therefore, the aperture hole 30B is located on the optical axis 2. In order to position the diaphragm hole 30C on the optical axis 2, it is sufficient to apply an electric pulse to the magnet 33 once more, and when it is desired to position the diaphragm hole 30D, it is possible to further overlap and apply an electric pulse once. .

When the diaphragm is selected by the diaphragm device 3 and the diaphragm plate 30 is moved, pre-exposure is performed by the image pickup device 1 partially blocked by the front blade 41 of the shutter device 4, and is used for the main photometry. At this time, about 30% of the lower part of the image pickup device 1 is shielded as shown in FIG. 1 because there is often an extremely bright portion for the subject such as the sky in this portion (the re-imaging optical system Due to this, the subject image is turned upside down and is formed on the image pickup device 1), and is unnecessary for photometry. Also, in the case of an image pickup device that does not have a storage unit, use this light shielding unit as a storage unit. In addition, by accumulating the subject portion near the center at the end of the light receiving surface of the image sensor 1, the charge transfer speed is increased.

In this way, photometry is performed by the image sensor 1, the diaphragm and the shutter speed are finally determined, and the main exposure is performed.

First, the diaphragm plate 30 moves until the diaphragm hole selected by the diaphragm device 3 is located on the optical axis 2. At the same time, the front blade 41 of the shutter device 4 rotates in the clockwise direction and stops at the position where the image sensor 1 is entirely shielded. When the diaphragm is determined, the leading blade 41 further rotates in the same direction, the image pickup element 1 starts exposure, and the trailing blade 51 follows the leading blade 41 in accordance with the shutter speed determined previously. When the image pickup device 1 is rotated, and the rotation is completed, the entire surface of the image sensor 1 is shielded.

The above operation will be described in more detail with reference to FIG.

In FIG. A, in the state where the front blade 41 shields the lower part of the image sensor 1 by about 30%, the image sensor 1 performs pre-exposure, that is, the diaphragm plate 30 moves to a predetermined position to open the hole of the plate 30. It is exposed to light incident through it. By using this output, photometry is performed and the final diaphragm is determined. After the diaphragm plate 30 moves to a predetermined position, when a predetermined shutter time elapses, the magnet 43 is energized, the armature part 42a of the armature 42 is attracted to the yoke 43y, and the armature 42 is centered around the axis 42j. Since the drive portion 42k pushes the base end portion 44k of the locking member 44 up against the tension of the coil spring 44S, the locking member 44 rotates counterclockwise about the shaft 44j. The engagement between the ratchet portion 44f and the protrusion 41a is released. Therefore, the leading blade 41 is rotated clockwise by the tension of the coil spring 41S, and the hook portion 44f of the locking member 44 causes the other protrusion 41b on the holding portion 41H of the leading blade 41 as shown in FIG. It abuts against the inner peripheral side surface 41b ₁ and stops. In this state, the image sensor 1 is. After resetting (the signal charges are read out from the device), preparation for main exposure is completed. When the resetting is completed and the magnet 43 is turned off, the armature 4
2, the locking member 44 returns to the original initial state, so the key 4
4f is disengaged from the inner peripheral side surface 41b ₁ and abuts on the outer peripheral side surface 41b ₂ of the projection 41b rotated further clockwise by the coil spring 41S as shown in FIG. 41 is stopped at a position where the image sensor 1 is not shielded.

In this way, the leading blade 41 can take two stages of positions by the ON / OFF operation of the magnet 43.

That is, in the initial state, the shutter device 4 shields about 30% of the lower portion of the image sensor 1, performs pre-exposure, performs photometry, and determines the diaphragm and shutter speed. And the magnet 43
ON, the leading blade 41 is rotated to a position where the image sensor 1 is completely shielded from light, resetting the image sensor, and then deenergizing the magnet 43 to start main exposure. Then, the engagement between the locking member 54 and the rear blade 51 is released by energizing the magnet 53 shown in FIG. 1, and the rear blade 51 is rotated clockwise by the coil spring.
It rotates by 51S and plays a role of shielding the image sensor 1 after the main exposure.

When the main exposure is completed in this manner, the diaphragm plate 30 is moved in the direction opposite to the arrow M against the tension of the coil spring 30S by the charge mechanism (not shown), and the front blade 41 and the rear blade 51 are coil springs.
The counters are moved counterclockwise against the tensions of 41S and 51S to return to the initial position and the charge is completed.

The positional relationship between the leading blade 41 and the trailing blade 51 in the leading axis 2 direction is
The blade that shields part of the image sensor 1 at the time of pre-exposure makes the boundary between the image forming part, that is, the part that is shielded and the part that is not shielded closer to the image sensor 1, the effect of shielding the image sensor. Can be done on a regular basis. Further, by using the blade that shields a part of the image pickup device 1 during the pre-exposure as the front blade 41, it is possible to perform a series of exposure sequences by moving in the same direction.

Next, a second embodiment having a simpler configuration and the same function as described above will be described with reference to FIG.

In the present embodiment, the first embodiment uses two blades, ie, the leading blade 41 and the trailing blade 51, as the traveling blades, but is configured by one blade.

As shown in FIG. 6A, the blade 61 has a shape in which three leading blades 41 are continuously provided to form a single main exposure hole 61A for the central blade, and the projection 61a to the holding portion 61H. The structure is almost the same as that of the shutter device 4 of the first embodiment except that 61d is provided. Since the diaphragm device is the same as that of the above-mentioned embodiment, its explanation is omitted.

In FIG. A, the locking member 44 and the protrusion 61a are locked, and the imaging element 1 is covered by the blade 61 at the lower part of about 330%.

When the pre-exposure is completed and the magnet (not shown) is energized,
The locking member 44 is released from the protrusion 61a and is rotated clockwise in the drawing by the tension of a coil spring (not shown). And the protrusion
The rotation is stopped by being locked by 61b, and the image sensor 1 is completely shielded as shown in FIG. Then, when the magnet is de-energized, the locking member 44 is projected as shown in FIG.
It is released from 61b and locked with the protrusion 61C. In this state, the image pickup device 1 is exposed through the exposure hole 61A, and after the time corresponding to the shutter speed, when the magnet is energized again,
As shown in FIG. 6D, the locking member 44 is released from the protrusion 61C, the blade 61 is further rotated, and the locking member 44 is released from the protrusion 61d.
Then, the rotation stops and the exposure is completed.

The charge mechanism of the exposure control member performed after the exposure is completed in the apparatus of the first embodiment described above will be described with reference to FIG. 5A, 5B and 5C are views showing the main part of the charge mechanism of the shutter front blade 41 whose plane is shown in FIG. 3, and FIG. 5A is the exposure state shown in FIG. FIG. B corresponds to the light-shielded state shown in FIG. 3B, and FIG. 5C corresponds to the charge completed state shown in FIG. 3A.

Figure 5 A, B, M is Chiyaji motor in C, G ₁ ~G ₃ is a gear for transmitting the driving force of the motor M, C is a cam which is connected to the gear G _3. On the front curtain 41, there is a roller K that can be lifted by a cam C made integrally with the gear G ₃ .
The gear G ₃ is connected to the motor M via the gear G ₂ and the gear G ₁ . SW is a photo interrupter and controls the rotation of the motor by detecting the presence or absence of a blade. When the motor M starts rotating counterclockwise in the drawing in the state shown in FIG. 5A, the gear G ₃ and the cam C rotate clockwise, and the cam C pushes the roller K upward in the drawing. , The front curtain 41 starts rotating counterclockwise. The state shown in FIG. 5C is reached through FIG. 5B. In this state, the roller K has been charged by the cam C to almost the initial state. Then, the photo interrupter SW detects the blade and stops energizing the motor M. The gear G ₁ ~G ₃ further rotates by inertia than the state of FIG. 5 C, roller K enters the place where fell most of cam C, that the cam is finished Chiyaji by one revolution. At this time, the leading blade of the shutter is locked by the locking member 44. Also, the rotation angle required for exposure of the rear curtain is smaller than that of the front curtain 41. Therefore, the front curtain can hook the rear curtain from the middle of the charge of the front curtain 41, and can be charged with the same mechanism. .

The charge of the expansion device 3 is also converted into a linear motion by rotating the cam once by the power of the motor as shown in FIGS. 5A, 5B and 5C, and is changed to the M direction in FIGS. 1 and 2. On the contrary, the diaphragm plate 30 can be moved and charged.

Further, as an embodiment other than the first and second embodiments, a dedicated blade may be provided to block a part of the image forming portion during the pre-exposure, and a total of three blades including a front blade and a rear blade may be used. The displacement limiting device 40 in the shutter device 4 of the first embodiment is the third one.
As shown in FIG. B, the magnet 43 is continuously energized and used to hold the position of the leading blade 41, but like the diaphragm device 3,
A method may be adopted in which an electric pulse is applied to the magnet once and the magnet is rotated by a certain predetermined amount corresponding to the number of times. Accordingly, the power consumption of the image pickup device can be reduced.

Further, in the case of a silver salt camera, instead of the image pickup element, the light receiving element may receive the reflection from the shutter surface or the film surface to perform photometry.

As described above, according to the present embodiment, after the pre-photometry, a part of the effective light flux is blocked by a part of the shutter, that is, a high-luminance part such as the sky is blocked, and the main photometry is performed by the signal from the imaging unit. That is, since the main exposure is performed after the pre-exposure is performed, there is an effect that highly accurate exposure control can be performed.

Next, an electric circuit of the image pickup apparatus configured as described above will be described with reference to FIG.

FIG. 6 is a block diagram of such an electric circuit.

In FIG. 6, 1 is a CCD as an image sensor, 1'is an image pickup optical system, 3 is a diaphragm device, 4 is a shutter device, and
As shown in the figure.

Reference numeral 5 is a signal processing circuit for adding various corrections to the luminance component and color component in the output signal of the CCD 1, and 6 is an integration for integrating the luminance signal appropriately formed in the signal processing circuit and sample-holding for each field. Circuit. Reference numeral 7 is an A / D converter, and the value A / G converted by the A / D converter 7 is taken into the control circuit 111. Reference numeral 13 is a sample and hold circuit that samples and holds the output of the SPC 19, which is a photometric element.
14 indicates the value held by the sample hold circuit 13.
It is an A / D converter that performs A / D conversion. Reference numeral 15 is a half mirror provided in the image pickup optical system. Reference numeral 17 is a servo circuit that controls the rotation state of a motor 29 that rotates the magnetic sheet 27.

Reference numeral 19 denotes the above-mentioned SPC, which is provided separately from the image sensor 1. Reference numeral 20 is a recording gate, which is a signal processing circuit 5.
It controls whether or not to send the image signal from the recording circuit 21.

Reference numeral 21 is the recording circuit, which is a circuit for modulating the image signal output from the signal processing circuit 5 into a form recordable on the magnetic sheet 27 via the head 25. Reference numeral 22 is a release circuit.
Reference numeral 23 is a half mirror for guiding a part of the reflected light of the half mirror 15 to the finder optical system 24, 25 is the head, and 27 is the magnetic sheet. Reference numeral 26 is a clock generation circuit for driving the image pickup device 1, and the timing of the clock generated by the control circuit 111 is controlled.

28 is a synchronous clock generator for generating a reference clock for synchronizing the entire system, and 100 is a diaphragm shutter drive circuit for driving the magnets 33, 43, 53 described above in FIG. 1 based on a command from the control circuit 111. Is.

The control circuit 111 functions as control means for the diaphragm device 3, the shutter device 4, and other circuit blocks, and outputs the output of the release circuit 22 for forming a release signal and the output of the synchronizing circuit 117 for forming a synchronizing signal, respectively. The control inputs X _{1 to} X ₃ as shown in the flow chart of FIG. 9 are output.

Next, the internal configuration of the clock generation circuit 26 will be described.

FIG. 7 is a block diagram showing the internal structure of the clock generation circuit 35. In FIG. 7, reference numeral 100 is a count that is a coefficient for the number of output pulses of the OR gate 107, and the value of the data buses D0 to D3 from the control circuit 111 is output from the OR gate 106 by the LOAD pulse 120.
Is an UP-COUNTER that counts when the enable signal 121 output from the RS-flip-flop (RS-FF) 103 is at a high level with this value as an initial value. 122 is a carry signal generated when the counter reaches the full count. This counter has a sufficient capacity to count the number of pixels in the vertical direction of the image sensor (CCD) 1. That is, in this embodiment, the number of vertical pixels of CCD 1 is 250, and the counter generates a carry signal when the count value reaches 250. 101 is a circuit that vertically transfers the charge accumulated in CCD1 and generates a timing signal for clearing CCD1, and generates a transfer pulse when the enable signal output from RS-FF104 shown in 123 is at a high level. To do. D0 to D3 are data buses provided between the control circuit 111 and the clock generation circuit 26, and four are shown in the embodiment, but the number is not limited to this. WR0 and WR1 are control lines provided between the control circuit 111 and the clock generation circuit 26, and RD0 is a determination line for determining the state of the clock generation circuit 26. A circuit 102 generates a timing signal for reading the charges accumulated in the CCD, and generates a transfer pulse when the enable signal output from the RS-FF 105 shown by 124 is at a high level.

An example of the structure of the CCD 1 used in this embodiment will be described with reference to FIG.

In FIG. 8, reference numeral 200 denotes an image pickup unit provided with stripe filters of R, G, B3 primary colors.
0 pixels are lined up. In addition, A, B, C shown in the imaging unit 200
The reference numerals are added as appropriate for the following description, and there is no structural difference, but the portion indicated by C is the portion shielded by the shutter front blade 41 at the position shown in FIG. 3A. Photoelectric conversion is performed in the image pickup unit, and charges corresponding to the amount of incident light are accumulated in each pixel. 201 to 203 are horizontal transfer registers for reading the image pickup signal transferred from the image pickup unit 200. In this embodiment, the CCD 1 receives a light beam when the diaphragm device 3 and the shutter device 4 are opened, and then the shutter device 4 is closed and then the horizontal transfer registers 201 to 203 are sequentially charged for each horizontal line. Although transferred, 201 is provided with an R stripe filter, and charges accumulated in the pixel, 202
In FIG. 7, φs ₁ and φs ₂ are the charges accumulated in the pixel provided with the G stripe filter and 203 are the charges accumulated in the pixel provided with the B stripe filter.
It is sorted and transferred by the pulse shown in. Also
Reference numeral 205 is an output amplifier unit that amplifies the signals read out from the horizontally transferred registers 201 to 203. Reference numeral 220 denotes a drain, which is arranged so that electric charges remaining in the horizontal shift registers 201 to 203 without being transferred when the transfer pulse generated by the generating circuit 101 is generated overflows.

Note that the transfer pulse φ shown in FIG.
The V and horizontal registers 201 to 203 are supplied with the transfer pulses φ _{H1 to} φ _H3 and φs ₁ and φs ₂ shown in FIG.

The circuit for generating these pulses can be realized by a combination of counter circuits, and a detailed description will be omitted here.

103 is set by the high level output of the OR gate 106 and is reset by the rising of the carrier signal 122 of the counter 100.RS-FFs 104 and 105 are set by the high level outputs of WR0 and WR1 from the control circuit 111, respectively. RS-FF reset by the rise of carrier signal 122
Is. Reference numerals 107 to 112 denote OR gates that take the logical sum of the pulses output from the clear transfer pulse generation circuit 101 and the read pulse generation circuit 102 at different timings, and are respectively connected to the CCD 1 as described above.

Next, the operation of the embodiment configured as described above will be described with reference to FIG.

FIG. 9 is a flow chart for explaining the operation of the control circuit 111 shown in FIG.

First, it is determined whether or not a signal indicating that the release switch is turned on is obtained from the release circuit 22 (S
1) If so, the sample-hold circuit 13 is driven to capture the output of the SPC 19 which is a photometric element as a photometric value (S2). Then, according to the captured photometric value, TV
A value and an AV value are calculated (S-1). In the diaphragm device 3 of the present embodiment, since there are three kinds of diaphragm light, 30B, 30C, and 30D, any one of the three kinds of AV values is selected, and the selected AV value and photometric value are selected. Since the TV value is calculated, the TV value is a continuous value. Next, the magnet 33 is energized according to the calculated AV value, and the diaphragm plate 3 shown in FIG.
In the direction (S-2). Due to this, the lower part C of CCD1
Is shielded by the shutter front blade 41 as shown in FIG. 3A, but the upper portions A and B are exposed. At the same time as the driving of the diaphragm is started, the control circuit 111 sets the control line WR0 shown in FIG. 6 to the high level and sets "0" to the data lines D0 to D3 (S4-1). Therefore, "0" is loaded into the transfer pulse counter 100, and RS-FF104 is set. Therefore, the clear transfer pulse generation circuit 101 causes the above φv.
Etc. pulses are output and CCD1 is cleared. The transfer pulse counter 100 counts the above-described pulse φv, and when the pulse φv reaches 250 pulses, that is, when all the signals accumulated in the imaging unit 200 are transferred, the carrier signal 122 is output, but the control circuit 111 By determining the carrier signal 122, it is determined whether or not the transfer is completed (S4-
2).

Next, it is determined whether or not the flag described later is set (S5). If the flag is not set, the above-mentioned S3 is set.
Wait only for the shutter time calculated in -1 (S7).

Even if the diaphragm 33 is energized, there is a delay of a predetermined time until the diaphragm is actually opened due to the response delay of the mechanical power transmission part such as the armature 32 and the locking claw 31 even if the magnet 33 is energized. , S4-1 and S4-2 complete the clearing of the charge accumulated in each pixel of CCD1 in an extremely short time, so the aperture actually opens and CC
When the exposure of D1 is performed, the charge of each pixel of CCD1 has already been cleared.

After waiting for the TV value calculated in S7, the magnet 43 shown in FIGS. 1 to 3 is energized (S8). As a result, the shutter device 4 shifts from the state shown in FIG. 3A to the state shown in FIG. 3B.

Following the energization of the magnet 43, the control circuit 111 sets the terminal WR0 to the high level and sets "150" to D0 to D3 (S-
9).

Therefore, a high level signal is input to the input terminal S of the RS-FF 104, and the data of 150 set by D0 to D3 is loaded into the transfer pulse counting counter 100.

The clear transfer pulse generation circuit 101 starts operating in response to the RS-FF104 being set by the next clock signal,
A pulse such as φv described above is generated. During this period, vertical transfer is performed at a higher speed than usual. Here, when φv reaches a pulse, the count value of the transfer pulse counting counter 100 becomes 250, and the carrier signal is output from the counter 100.

The RS-FFs 104 and 105 are reset in response to the carrier signal, and the generation of the transfer pulse is temporarily stopped. Then the control circuit
111 judges that the transfer is completed by the carrier signal, and then S11
The flow proceeds from S to S13. At this point, the electric charge of the portion B shown in FIG. 8 is transferred to the portion shown in C.

Even when the shutter is driven in S8, the shutter actually travels from the position shown in FIG. 3A to the position shown in FIG. 3B due to the response delay caused by the mechanical power transmission unit as in the above-described diaphragm drive. Although there is a delay of a predetermined time before, the charges of the image pickup unit are transferred at an extremely high speed by executing S9 and S11, so that the charges of the portion shown in FIG. The signal is transferred to the portion that is shielded from the shutter from the beginning as shown in C, and the signal is not deteriorated under the influence of external light.

In addition, the time when the charge integrated by the integrating circuit 6 is generated, that is, after the image pickup unit 200 of the CDD1 is cleared in S4-1 and S4-2, the area indicated by B of the image pickup unit 200 of the CCD1 is changed to C in S9 and S11. The time until transfer to the area shielded by the shutter front blades shown does not depend on the response delay of the mechanical power transmission system of the shutter device, and
Exists only at the timing of the control signal supplied from the clock generator circuit 26 to the clock generator circuit 26. Therefore, in this embodiment, the pre-exposure time can be controlled extremely accurately.

Next, the control circuit 111 sets the control line WR1 to the high level to D0.
~ Set 200H to D3 (S15).

Therefore, a high level signal is input to the input terminal S of the RS-FF 105, and 200H data set by D0 to D3 is loaded into the transfer pulse counting counter 100.

In response to the RS-FF 105 being set by the next clock signal, the read pulse generation circuit 102 starts its operation and generates the above-mentioned pulse of φv or the like. Since the pulse generated by the read pulse generation circuit 102 is a normal read pulse, the signal of the image pickup unit 200 is read from the horizontal shift registers 201 to 203, and the read signal is shown in FIG. 6 as described above. It is integrated by the integrating circuit 6. The output of the integrating circuit 6 is fetched in S24 described later.

In this case, in S9 and S11, since the video signal for 100 lines is discarded to the drain 220, the video signal for 50 lines in the center of the screen is used for such integration.

Therefore, as described above, the signal of a high-luminance portion such as the sky that forms an image on the lower part of CCD1 is not used for such integration.

When φv of 50 pulses is output, the count value of the transfer pulse counting counter 100 becomes 250, and the carrier signal is output from the counter 100. When it is detected that the reading is completed by detecting the carrier signal, the flow proceeds from step S17 to step S19.

Steps S19 and S21 are the same as steps S9 and S11 described above, and therefore description thereof will be omitted.

When the transfer of the image pickup unit 200 is completed as described above, the flag is set in S23, the flow returns to S5, and then the flow branches from S5 to S24.

Next, the integrated value of the integrating circuit 6 shown in FIG.
(S24), the TV value is recalculated from the integrated value so that the integrated value becomes a predetermined value, and the actual shutter time TV value is obtained (S25). Then, the magnet 43 is de-energized (S26) and the shutter is moved from the position shown in FIG. 3B to the position shown in FIG. 3C.

Next, after waiting for only the actual shutter time TV (S27), the magnet 53 is energized, the rear blades 51 are made to run, and the front surface of the CCD 1 is shielded.

In S30, the terminal WR1 is set to the high level and D0 to D0 are set to "0". Then, in the same manner as described in S15, the read pulse generation circuit 102 starts to operate, the normal reading is started from the image pickup unit 200, the recording gate 20 is opened in S32, and the recording circuit 27 opens one screen image. The signal is recorded.

When the end of transfer is detected, that is, the recording circuit 27 sets 1
When the recording of the video signal for the screen is completed, the flow proceeds from S34 to S36, the recording gate 20 is closed, the charge motor is energized, the state of the switch SW shown in FIG. 5 is switched, and the charge of the shutter and the diaphragm is changed. When completed, the flow ends and returns to S1.

As described above, in the present embodiment, photometry is performed by the SPC 19, and after controlling the aperture in advance, the shutter is opened for a predetermined shutter time and the signal of the image sensor accumulated during that time is read out, and the exposure is performed according to the signal. When performing control, the signals of the image sensor that are not used for exposure control are read out at high speed and discarded, so that the output of the image sensor can be controlled very accurately and the release circuit can be used.
The time lag from the release signal output from 22 to the actual image recording can be made extremely small.

Further, in the configuration of the clock generation circuit 35 of this embodiment shown in FIG. 7, the pulse output from the pulse read pulse generation circuit 102 output from the clear pulse generation circuit 101, and the same count when counting any number of pulses. counter
Since 100 is used, the configuration can be extremely simple.

In addition, the counting counter 100 is a presettable counter,
Since the clock generation circuit 35 is configured so as to be preset from the outside of the clock generation circuit, it is possible to read the signal of any portion other than the central portion of the screen of the image pickup device in an extremely short time as in the present embodiment, and it should be read. The size of the part can be freely set from the outside. As a result, such a clock generation circuit can be used for exposure control and also for applications such as evaluation photometry. That is, the present invention can be used in applications such as evaluation photometry.

In the present embodiment, the up counter is used as the counter for counting the transfer pulse, but of course this may be a down counter. In this case, the value of the pulse number itself to be transferred may be preworded.

<Advantages of the Invention> As described above, according to the present invention, the image pickup device obtained in such a state has the light-shielding means for stopping in a state where only a part of the light receiving surface of the image pickup device is shielded from light. By using the output of, for example, the exposure value can be controlled without being affected by a bright portion such as the sky.

[Brief description of drawings]

FIG. 1 is a perspective view of a diaphragm device and a shutter device of a first embodiment of the present invention, FIG. 2 is a front view of the diaphragm device, FIG. 3 is a front view showing the operation of the shutter device, and FIG. FIG. 6B is a diagram showing a state in which the front blade 41 shields the entire surface of the image pickup device 1 from light, and FIG. 7C is a diagram showing a state in which the front blade 41 is running to expose the image pickup device. , Fig. 4 shows the first
It is a figure for demonstrating the other Example of the shutter device 4 used for the figure, and the figure A-the figure C correspond to FIG. 3A-the figure 3C, respectively, and the same figure D shows an image sensor. 1 shows a state where the entire surface is shielded from light, FIGS. 5A, 5B and C show the charge mechanism of the shutter device shown in FIG. 1, and FIG. 6 is a block diagram of the electric circuit of the image pickup device. FIG. 7 is a block diagram showing the internal structure of the clock generation circuit shown in FIG. 6, FIG. 8 is a plan view of the CCD which is the image pickup device 1, and FIG. 9 is the operation of the control circuit 111 shown in FIG. It is a flow chart for explaining. 1 ... Image sensor 2 ... Optical axis 3 ... Aperture device 4 ... Shutter device 26 ... Clock generation circuit 111 ... Control circuit

Front page continued (72) Inventor Nobuo Fukushima, 770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Canon Inc., Tamagawa Plant (72) Shinji Sakai, 770, Shimonoge, Takatsu-ku, Kawasaki, Kanagawa Prefecture (56) References JP-A-59-104867 (JP, A) JP-A-58-107779 (JP, A)

Claims (1)

[Claims] 1. An image pickup device, a light-shielding device having a first state in which the entire light-receiving surface of the image pickup device is shielded and stopped, and a second state in which only a part of the light-receiving surface is shielded and stopped. An image pickup apparatus comprising: