JPH10221740A - Image pickup unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image pickup unit excellent in the protective function of an imaging means, and which is small-sized, and whose power consumption is low, and which copes with the increase of the number of picture elements. SOLUTION: Incident field light is image-formed on a specified image-formation surface by an image pickup optical system, and is photoelectrically converted and outputted by the image pickup means. This unit has blade members 4 and 5 arranged so as to be able to enter an image pickup optical path leading to the image pickup means from the image pickup optical system, and the blade members 4 and 5 are converted and driven between a first state where they are retreated to the outside of the image pickup optical path and a second state where they enter the inside of the image pickup optical path by a blade driving means 6. Since the blade driving means 6 is constituted of, for instance, a moving magnet, and is held in a non-energizing state by a holding means, for instance, in iron pin or the like, power consumption in accordance with holding is eliminated even though the blade members 4 and 5 are held at the most desirable position in accordance with a change in the state of a camera. Therefore, the power consumption is restrained even though the protection of the image pickup means and real image display or the like for a liquid crystal finder are performed, and also the exposure is completed by the blade members 4 and 5, so that the unit copes with the increase of the number of the picture elements.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus, and more particularly to an image pickup apparatus for obtaining a still image by photoelectrically converting a subject image like a so-called electronic still camera.

[0002]

2. Description of the Related Art In recent years, an image pickup device which photoelectrically converts a subject image to obtain a still image has been widely used as a still camera together with a so-called silver halide camera. As an exposure control in this type of imaging apparatus, there is also known an exposure control in which the exposure time is controlled by controlling the time from ON to OFF of an imaging unit. Has a problem that a time shift occurs between the odd-numbered lines and the even-numbered lines due to the influence of the interlace, and the outer shape of the subject is jagged. Recently, in order to solve such a problem, non-interlaced image sensors capable of outputting full-frame images are becoming widespread. It becomes very expensive, and there is a demand for providing a shutter device to shield the image pickup device from the field light while capturing image data. Also, in the case of a still-type so-called electronic camera or digital video camera, exposure correction in a developing station cannot be expected unlike a silver halide film camera, and the exposure tolerance is narrower than that of a silver halide film. At times, there is a desire to control independently. In the case of a silver halide film camera, a camera in which a single actuator is used also as a drive source for a diaphragm blade and a shutter blade is widely used. Generally, such a mechanism drives the aperture mechanism to a target position in the first stage of operation of the actuator, locks the aperture mechanism with a latch mechanism such as a ratchet, and then releases the shutter mechanism in the second stage of operation of the actuator. Is driven to open and close.

[0003]

However, the so-called electronic still camera has a much smaller image sensor area than a silver halide film such as a general 35 mm film or a new standard film. There is a strong demand for maintaining a large aperture only for the lens aperture, and the mounting space for the blade drive mechanism tends to be narrower. As described above, when a single actuator is also used as a drive source for the aperture mechanism and shutter mechanism, However, there is a problem that mounting becomes difficult because the power transmission system becomes complicated and a lock mechanism and a lock release mechanism for locking the aperture mechanism must be provided.

In order to solve this problem, it is effective to provide independent actuators for both the diaphragm mechanism and the shutter mechanism, and to drive each blade directly with each actuator. Incidentally, in the case of an electronic camera, a so-called normally closed type in which the shutter blades are closed to protect the imaging means from the field light when the camera is not used is desirable, while a monitor such as a liquid crystal finder is used when the power is turned on. There is a demand to maintain the shutter in an open state in order to project a subject image on the apparatus, but if the current is continuously supplied to maintain the shutter blades in the open position when the power is turned on, the power is significantly consumed. Occurs. In particular, in the case of an electronic camera, the size of the camera is smaller than that of a silver halide camera, and power is also consumed for displaying a finder, recording an image, and the like. Therefore, there is a strong demand for minimizing power consumption.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to reduce the size of the periphery of a shutter, to protect an image pickup device and to display a liquid crystal finder, and to reduce power consumption. It is an object to provide an imaging device. In summary, the imaging apparatus according to claim 1 of the present invention includes: an imaging optical system that forms incident light on a predetermined imaging surface;
Imaging means arranged on an image plane on which incident light is imaged by the imaging optical system; and a blade member arranged so as to be able to enter into an imaging optical path from the imaging optical system to the imaging means; A first state in which the blade member is retracted outside the imaging optical path and a second state in which the blade member enters the imaging optical path.
The above object is achieved by providing: a blade driving unit that drives between the states; and a holding unit that holds the blade driving unit in the first state or the second state in a non-energized state.

[0006] The imaging device according to claim 2 is based on claim 1. The blade driving means is constituted by a moving magnet whose output end turns within a predetermined angle range corresponding to a current supply direction: The holding means is made of a ferromagnetic material arranged at the limit of the turning operation of the moving magnet.

Further, an image pickup apparatus according to a third aspect of the present invention includes: a photographing optical system for forming an incident light on a predetermined image forming surface; and an image pickup arranged on an image forming surface on which the incident light forms an image by the photographing optical system. Means: one or a plurality of aperture blade members disposed so as to be able to enter into an imaging optical path from the imaging optical system to the imaging means, and controlling the aperture value; Diaphragm blade driving means for driving between a first state retracted outside the photographing optical path and a second state entered into the photographing optical path: enabling entry into the photographing optical path from the photographing optical system to the image pickup means A shutter blade member disposed to open and close the photographing optical path: between a first state in which the shutter blade member is retracted outside the photographing optical path by supplying drive power and a second state in which the shutter blade member enters the photographing optical path. -Driven shutter blades Drive means and: a holding means for holding the blade blade driving means of said each in the first state or the second state in a non-energized state: To achieve the above object by having a.

According to a fourth aspect of the present invention, on the basis of the third aspect, the image pickup device includes a charge-coupled device as the image-capturing means. An image pickup apparatus comprising: an exposure control unit that controls an exposure time by controlling a time until the shutter blade member is driven from the first state to the second state.

According to a fifth aspect of the present invention, there is provided the imaging apparatus according to the third or fourth aspect, wherein the shutter blade driving means and the aperture blade driving means are arranged such that an output end thereof has a predetermined angle corresponding to a current supply direction. Consisting of a moving magnet that pivots within a range: the holding means is composed of a magnetic material arranged at the limit of the pivoting movement of the moving magnet.

That is, according to the present invention, since the blade member is provided so as to be able to enter into the image pickup optical path from the image pickup optical system to the image pickup device, the image pickup means can be protected when not in use and the image pickup means can be protected. The number of pixels can be easily increased,
In addition, even when power is not supplied, the blade driving member is held by the holding means in a state where the blade member is retracted outside the imaging optical path or enters the imaging optical path, so that wasteful power consumption is suppressed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing a state in which a power supply of a camera body of an imaging apparatus according to the present invention is turned off, and FIG. 2 is a sectional view showing a periphery of a moving magnet. In FIG. 1, reference numeral 1 denotes an upper base plate, 2 denotes a middle base plate, and 3 denotes a base plate. In FIG. 1, the upper base plate 1, the middle base plate 2 and the base plate 3 are virtually shown by the same dashed line. An exposure opening AP that forms an image pickup optical path is formed in a central portion of these ground plates.
Reference numerals 4 and 5 denote shutter blades for opening and closing the exposure opening AP.
The shutter blades 4 and 5 are swingably supported by pins 1a and 1b implanted on the back surface of the upper base plate 1, respectively.
Note that the shutter blades 4 and 5 shown in this embodiment do not have aperture forming edges, and are in a state of blocking the exposure opening AP when not in use.

Reference numeral 6 denotes a moving magnet for driving the shutter blades 4 and 5 to open and close. FIG. 2 is a sectional view, and FIG. 3 is an enlarged plan view of FIG.
The reference numerals of the components of the moving magnet 6 are not particularly shown in FIG. 1, but can be understood by referring to FIGS. The moving magnet 6 has a cylindrical casing 6a.
The coil frame 6b is fixed to the inside of the coil frame 6b.
The coil 6c is wound along the longitudinal direction as shown in FIG. A two-pole magnet 6e is rotatably supported on a shaft 6d provided inside the coil frame 6b, and an output pin 6f protruding outside the magnet 6e is connected to the upper ground plate 1.
The shutter blades 4 and 5 penetrate the middle base plate 2 and are respectively engaged with long holes 4a and 5a (see FIG. 1) formed in the shutter blades 4 and 5, respectively.

The operating range of the output pin 6f is the pins 1c, 1 made of a ferromagnetic material such as iron implanted on the upper base plate 1.
d. Output pin 6f in the initial state
The pin 1c is magnetically attached and held in the state shown in FIGS. 1 and 3, but when a positive pulse current is supplied to the coil 6c in this state, the upper side in FIG.
A magnetic field that becomes a pole is formed, the magnet 6e rotates counterclockwise about the shaft 6d, and the output pin 6f comes into contact with the pin 1d and stops. Since the output pin 6f magnetically attaches the pin 1d, even if the supply of the positive pulse current is cut off, the output pin 6f is maintained in a state where the pin 1d is magnetically attached. When a negative pulse current is supplied to the coil 6c from a state in which the output pin 6f magnetically attaches the pin 1d, a magnetic field having a lower N pole in FIG. 3 is formed around the coil frame 6b. 6e rotates clockwise about axis 6d,
The output pin 6f comes into contact with the pin 1c and stops. Since the output pin 6f magnetically attaches the pin 1c, even if the supply of the negative pulse current is cut off, the output pin 6f is maintained in a state where the pin 1c is magnetically attached.

In this embodiment, it is assumed that three types of aperture control, large, medium and small, are performed, and the fully opened state of the exposure opening AP corresponds to the large aperture. The medium and small apertures are obtained by moving the aperture blades 7 or 8 into the exposure openings AP, respectively. First, the aperture blade 7 corresponding to the medium aperture is swingably supported by a pin 1e implanted in the upper base plate 1, and an opening 7 corresponding to the medium aperture is provided at the tip of the aperture blade 7.
a is formed. Reference numeral 9 denotes a moving magnet serving as a driving source for rotating the diaphragm blade 7. The structure of the moving magnet 9 is basically the same as that of the moving magnet 6 already described, and an output pin 9f is formed on the diaphragm blade 7. With the elongated hole 7b. In the present embodiment, the moving magnet 9 rotates clockwise around the shaft 9d by supplying a positive pulse current until the output pin 9f contacts the ferromagnetic pin 1f. By supplying a current, the pin rotates counterclockwise about the axis 9d until it comes into contact with the ferromagnetic pin 1g. When the output pin 9f of the moving magnet 9 is in contact with the pin 1f, the opening 7a formed in the diaphragm blade 7 is substantially concentric with the opening 7a.

Next, the aperture blade 8 corresponding to the small aperture is swingably supported by a pin 1h planted on the upper base plate 1, and an opening 8 corresponding to the small aperture is provided at the tip of the aperture blade 8.
a is formed. Reference numeral 10 denotes a moving magnet serving as a drive source for rotating the aperture blade 8, and the structure of the moving magnet 10 is basically the same as that of the moving magnet 6 already described.
Are engaged with a long hole 8b formed in the aperture blade 8.
In this embodiment, the moving magnet 10
Is connected to output pin 1 by supplying a positive pulse current.
0f rotates clockwise around the axis 10d until it comes into contact with the ferromagnetic pin 1i, and supplies a negative pulse current to rotate counterclockwise around the axis 10d until it comes into contact with the ferromagnetic pin 1j. To rotate. An opening 8 a formed in the aperture blade 8 is provided with an output pin 1 of the moving magnet 10.
When 0f is in contact with the pin 1i, the opening 8a and the exposed opening AP are substantially concentric.

Next, FIG. 4 is a block diagram of the control system of the present embodiment. Reference numerals 4 and 5 denote the aforementioned shutter blades 4 and 5, and reference numerals 7 and 8 denote the aforementioned aperture blades 7 and 8. , 6,9,1
Reference numeral 0 denotes the moving magnets 6, 9, and 10 described above. Reference numeral 11 denotes a photographing lens, 12 denotes a CCD serving as an image pickup means, 13 denotes an image signal processing circuit for performing processing for storing image signals output from the CCD 12, 14 denotes a shutter release switch, 15 denotes a main switch, and 16 denotes a micro switch. Reference numeral 17 denotes a computer. Reference numeral 17 denotes a shutter drive circuit for supplying a drive signal to the moving magnet 6 for driving the shutter. Reference numeral 18 denotes a diaphragm drive circuit for supplying a drive signal to the moving magnets 9 and 10 for driving the aperture. Denotes an electronic shutter control circuit for controlling charge accumulation and charge release of the CCD 12, respectively.

Next, the above items, the flowchart of FIG.
The operation of the present embodiment will be described in detail with reference to the time chart of FIG. 6 and the plan views showing the state changes of FIGS. 7 and 8.
First, in the initial state, the mechanism is in the state shown in FIG.
When the main switch 15 is turned on, the program starts, and the microcomputer 16 controls the electronic shutter control circuit 19 to start the operation of the CCD 12 and also controls the shutter drive circuit 17 to control the moving magnet 6 with a positive pulse current. Is supplied. (Steps S2 and S3)

When a positive pulse current is supplied to the moving magnet 6, the output pin 6f is connected to the shaft 6d.
Around the pin 1d until it comes into contact with the pin 1d. When the output pin 6f contacts the pin 1d, the output pin 6f magnetically attaches the pin 1d, so that the position of the output pin 6f is maintained even in a non-energized state after the positive pulse current falls. In this way, when the output pin 6f rotates counterclockwise from the state shown in FIG.
Since the shutter blades a and 5a are engaged with each other, the shutter blade 4 turns left around the shaft 1a, and the shutter blade 5 turns right around the shaft 1b to open the exposure opening AP. 7 and 8 show a state where the shutter blades 4 and 5 have opened the exposure openings AP.

Since the operation of the CCD 12 has already been started, when the shutter blades 4, 5 open the exposure aperture AP and the CCD 12 is exposed to the field light as described above,
The output of the CCD 12 is applied to a microcomputer 16. Then, the microcomputer 16 measures the field brightness from the output of the CCD 12, calculates an appropriate aperture value and shutter time, and waits for the release switch 14 to be turned on (step S4). And release switch 14
Turns on, the process branches according to the aperture value calculated in step S4 (step S9).

When the aperture value to be used is the middle aperture, the microcomputer 16 controls the aperture drive circuit 18 to supply a positive pulse current to the moving magnet 9 (step S10). Turn clockwise around 9d until it comes into contact with pin 1f.
Since f is magnetized, the clockwise position is maintained even in the non-energized state in which the positive pulse current has fallen. Then, along with the clockwise rotation of the moving magnet 9, the aperture blade 7 also rotates clockwise about the shaft 1e, and the opening 7a narrows the exposed aperture AP to the middle aperture. FIG. 7 shows that the opening 7a is exposed in this manner.
Shows a state in which the aperture is stopped down to the middle aperture. When the aperture value used is small, the microcomputer 16
Controls the aperture driving circuit 18 to control the moving magnet 1
A positive pulse current is supplied to 0 (step S11), and the moving magnet 10 turns clockwise around the shaft 10d until the output pin 10f contacts the pin 1i to magnetize the pin 1i. The right-handed rotation position is maintained even when the power is turned off. And moving magnet 1
With the clockwise rotation of 0, the aperture blade 8 also rotates clockwise about the axis 1h, and the aperture 8a narrows the exposure aperture AP to a small aperture.
FIG. 8 shows a state in which the aperture 8a narrows the exposure aperture AP to a small aperture in this way. Further, when the aperture value to be used is a large aperture, the operation of reducing the aperture is not performed, and the process immediately proceeds to step S12. That is, in this case, the aperture value becomes the aperture value without changing the aperture of the exposure aperture AP.

When the aperture value is determined in this manner, the microcomputer 16 controls the electronic shutter control circuit 19 to discharge the charge stored in the CCD 12 (step S1).
2). Then, the CCD 12 starts accumulating the electric charge again from the time when the discharging operation is completed. Therefore, this timing is the start timing of the effective exposure second. Since the proper exposure time has already been calculated in step S4, the microcomputer 16 controls the shutter drive circuit 17 when the exposure time calculated in step S4 elapses after discharging the accumulated charge of the CCD 12 in step S12. To supply a negative pulse current to the moving magnet 6 (step S1).
4). When a negative pulse current is supplied to the moving magnet 6, the output pin 6f rotates clockwise around the shaft 6d until it comes into contact with the pin 1c. When the output pin 6f contacts the pin 1c, the output pin 6
Since f magnetically attaches the pin 1c, the position of the output pin 6f is maintained even in a non-energized state after the negative pulse current has fallen. When the output pin 6f rotates clockwise from the state shown in FIG. 7 or 8 in this manner, the shutter blade 4
The shutter blade 5 rotates clockwise around the axis a and the shutter blade 5 to block the exposure opening AP. Accordingly, in the case of large-diameter photography in which the aperture diameter is determined by the exposure aperture AP, the total area of the hatched portion ABC in FIG. 6 corresponds to the effective exposure amount, and in the case of medium-diameter photography in which the aperture diameter is determined by the aperture 7a of the diaphragm blade 7. In FIG. 6, the total area of the hatched portion BC in FIG. 6 corresponds to the effective exposure amount. In the case of small-diameter photography in which the aperture diameter is determined by the opening 8a of the diaphragm blade 8, the area of the hatched portion C in FIG. Would be equivalent.

When the shutter blades 4, 5 cover the exposure aperture AP in this manner, the microcomputer 16 controls the image signal processing circuit 13 to take in the output of the CCD 12 (step S15), and the image signal processing circuit 13 The signal is written to a storage device such as an external memory card, for example, and one shooting operation is completed. When one photographing operation is completed in this way, the microcomputer 16 prepares for photographing the next frame as follows. That is, the microcomputer 1
Step 6 determines in step S16 whether the diaphragm blade 7 or 8 has been used. A negative pulse current is applied to the moving magnet 9 if the aperture blade 7 is used, and to the moving magnet 10 if the aperture blade 8 is used, and the aperture blade 7 or the aperture blade 8 is plotted. After returning to the initial state shown in FIG. 1 (step S17), the process returns to step S3 to open the shutter blades 4 and 5, and waits for the release switch 14 to be turned on in step S8. The moving magnets 9 and 10 keep the output pins 9f and 10f and the pins 1g and 1j even after the negative pulse current is stopped.
Needless to say, the state shown in FIG. In this manner, the release switch 14 is
When it is detected in step S5 that the power switch 15 has been turned off while waiting for the power to be turned on, the shutter drive circuit 17 is controlled in step S6 to apply a negative pulse current to the moving magnet 6 and The exposure operation is terminated by driving the shutter 5 closed. The control operation after the power switch 15 is turned off is executed by, for example, supplying power from a capacitance circuit such as a capacitor (not shown).

In the above description, an example in which the present invention is applied to a camera having both a shutter blade and an aperture blade independently has been described. It is also possible to apply independently.

[0024]

As described above, according to the present invention, the holding operation is performed both when the blade member is held in the first state retracted outside the imaging optical path and when it is held in the second state after entering the imaging optical path. Since the power consumption does not occur, the blade member is held in the second state when the power is turned off to protect the imaging means, and when the power is turned on, the blade member is held in a standby state until the release switch is operated. Since the liquid crystal finder can be used by holding the first state, the exposure operation can be completed by driving the blade member from the first state to the second state to mechanically shield the imaging optical path. , The number of pixels can be effectively increased. The power consumption for driving the blades is only when reversing the position of the blades and no power is consumed for the holding operation. In this case, power consumption can be reduced as a whole, and the number of frames to be shot can be increased.

[Brief description of the drawings]

FIG. 1 is a plan view of an imaging device according to an embodiment of the present invention in an initial state.

FIG. 2 is a cross-sectional view of the moving magnet 6 shown in FIG.

FIG. 3 is an enlarged plan view of the moving magnet 6 shown in FIG.

FIG. 4 is a block diagram of a control system of the imaging apparatus according to the embodiment of the present invention.

FIG. 5 is a flowchart showing a control operation of the control system shown in FIG. 4;

FIG. 6 is a time chart showing operation timings of the control system shown in FIG. 4;

FIG. 7 is a plan view showing the embodiment shown in FIG. 1 in a middle aperture state.

8 is a plan view showing the embodiment shown in FIG. 1 in a small aperture state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper ground plate 1c, 1d, 1f, 1g, 1i, 1j Pin 4, 5 Shutter blade 6 Moving magnet 6f Output pin 7 Middle aperture diaphragm blade 7a Opening 8 Small aperture diaphragm blade 8a Opening 9 Moving magnet 9f Output pin 10 Moving Magnet 10f Output pin 11 Lens 12 CCD 16 Microcomputer AP Exposure opening

Claims (5)

[Claims] A photographing optical system for forming an incident light on a predetermined image forming surface; an image pickup means disposed on an image forming surface on which the incident light forms an image by the photographing optical system; A blade member disposed so as to be able to enter the imaging optical path to the imaging means; a first state in which the blade member is retracted outside the imaging optical path by supplying drive power; and a second state in which the blade member enters the imaging optical path. A blade driving means for driving the blade driving means between the first state and the second state when the blade driving means is not energized;
An image pickup apparatus comprising: a holding unit that holds a state. 2. An image pickup apparatus according to claim 1, wherein said blade driving means is constituted by a moving magnet whose output end turns within a predetermined angle range in accordance with a current supply direction. An imaging apparatus comprising a ferromagnetic material disposed at a limit of a turning operation of the moving magnet. 3. An imaging optical system for forming an image of incident light on a predetermined imaging surface, imaging means arranged on an imaging surface on which the incident light forms an image by the imaging optical system, and A first or a plurality of aperture blade members that are disposed so as to be able to enter the imaging optical path to the imaging means and control the aperture value, and a first power supply member that retracts the aperture blade member out of the imaging optical path by supplying drive power; Diaphragm blade driving means for driving between a state and a second state which has entered the photographing optical path; and a shutter which is disposed so as to be able to enter the photographing optical path from the photographing optical system to the imaging means and opens and closes the photographing optical path. A blade member, shutter blade driving means for driving the shutter blade member between a first state in which the shutter blade member is retracted outside the photographing optical path and a second state in which the shutter blade member enters the photographing optical path by supplying drive power;
An image pickup apparatus comprising: a holding unit that holds each of the blade driving units in the first state or the second state in a non-energized state. 4. The imaging apparatus according to claim 3, further comprising a charge-coupled device as said image-capturing means, and, after discharging the charge stored in said charge-coupled device, said shutter-blade driving member switches said shutter-blade member. An imaging apparatus, comprising: an exposure control unit that controls an exposure time by controlling a time period from when the first state is driven to the second state. 5. An image pickup apparatus according to claim 3, wherein said shutter blade driving means and said aperture blade driving means rotate at an output end within a predetermined angle range corresponding to a current supply direction. It is composed of a moving magnet,
The imaging device according to claim 1, wherein the holding unit is formed of a magnetic body disposed at a limit of a turning operation of the moving magnet.