JP3977575B2 - Imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an imaging apparatus, and more particularly to an imaging apparatus that obtains a still image by photoelectrically converting a subject image like a so-called electronic still camera.
[0002]
[Prior art]
In recent years, an image pickup apparatus that photoelectrically converts a subject image to obtain a still image is becoming widespread as a still camera field together with a so-called silver film camera. As for exposure control in this type of image pickup device, there is known a method in which the exposure time is controlled by controlling the time from on to off of the image pickup means. However, there is a problem that due to the interlace effect, there is a time shift between the odd lines and the even lines, and the outer shape of the subject is jagged. Recently, in order to solve such a problem, an image sensor capable of outputting a full frame image in a non-interlaced manner has been widely used. Since it becomes very expensive, there is a demand to provide a shutter device to shield the image sensor from the field light during the capture of the image data. In the case of still-type electronic cameras and digital video cameras, exposure correction cannot be expected at a development place like a silver salt film camera, and the exposure tolerance is narrower than that of a silver salt film. There is a desire to control at times. In the case of a silver salt film camera, a camera in which a single actuator is used as a driving source for a diaphragm blade and a shutter blade is widely used. In general, such a mechanism is such that, in the first stage of the operation of the actuator, the diaphragm mechanism is driven to a target position and the diaphragm mechanism is locked by a latch mechanism such as a ratchet, and then the shutter mechanism is operated in the second stage of the operation of the actuator. It is made to open and close.
[0003]
[Problems to be solved by the invention]
However, the so-called electronic still camera has an image sensor area that is much narrower than silver film such as a general 35 mm film or new standard film, so the lens barrel periphery is downsized while only the lens aperture remains large. There is a strong desire to do so, and the mounting space of the blade drive mechanism tends to be reduced. As described above, when a single actuator is used as a drive source for the aperture mechanism and shutter mechanism, the power transmission system is complicated. In addition, since a locking mechanism and a locking release mechanism for locking the aperture mechanism must be provided, there is a problem that mounting becomes difficult.
[0004]
In order to solve this problem, it is effective to provide independent actuators for both the aperture mechanism and the shutter mechanism and to directly drive each blade by each actuator. By the way, in the case of an electronic camera, a so-called normal close type in which the shutter blades are closed in order to protect the imaging means from the field light when the camera is not used is desirable. There is a request to keep the shutter open to project the subject image on the device. However, if current is continuously supplied to keep the shutter blades in the open position when the power is turned on, the power consumption is significant. Occurs. In particular, in the case of an electronic camera, since the camera size is reduced as compared with a silver halide film camera and power is consumed for finder display and image recording, there is a strong demand for suppressing power consumption as much as possible.
[0005]
[Means for Solving the Problems]
The present invention has been made in view of such problems, and an object of the present invention is to provide an imaging apparatus that can reduce the size of the periphery of the shutter and that can protect the imaging element and display the liquid crystal finder while consuming less power. To do.
In summary, the imaging apparatus according to claim 1 of the present invention: the photographing optical system for focusing incident light to a predetermined imaging plane and: imaging means disposed in said image plane: each exposure opening At least two ground planes having the exposed openings disposed in the optical path of the incident light; and disposed between the ground planes and rotatably attached to one of the ground planes. A diaphragm blade member operable between a first position retracted from the exposure opening and a second position entering the exposure opening and forming an opening smaller than the exposure opening; and between the base plate It is disposed and rotatably attached to one of the ground planes, and is operated between a first position retracted from the exposure opening and a second position entering the exposure opening by rotating. Shutter blade member to be rotated: rotatable The diaphragm blade member to pivot the magnet when the drive current has a stone is supplied is operated between the first position and the second position, the magnet when the drive current is not Tei is supplied A diaphragm blade driving means for holding the shutter blade member so as not to rotate: When a drive current is supplied to the aperture blade driving means, the magnet is rotated to move the shutter blade member to the first position and the second position. in the end stage of the operation is not captured between the actuated to the second position said shutter blade member from said first position, when the driving current is not Tei supplied shutter blade driving means for holding so as not to pivot the magnet And: calculating the aperture value and shutter speed from the field luminance, and controlling the supply of the drive current to each of the drive means according to the calculation result, and when the power is turned on, the shutter blade drive When the power is operated to the first position said shutter blade member from said second position is turned off by means actuates to the second position from the first position, the diaphragm based on the calculation result to the release time of shooting to release the charge accumulated in the image pickup means from have you decide the position of the blade member to actuate the shutter blade member and the shutter speed has elapsed into the second position, then, the said shutter blade member And the control means adapted to be actuated to the first position.
[0006]
An imaging apparatus according to a second aspect is based on the first aspect: the diaphragm blade driving means rotates within a predetermined angular range, and the angular range includes a rotation shaft of the diaphragm blade driving means and a support shaft of the diaphragm member. It should be set to a range that is almost equiangular with a straight line passing through.
[0007]
That is, according to the present invention, since the shutter blade member that can enter the exposure opening is provided, it is possible to protect the imaging means when not in use and to easily increase the number of pixels of the imaging means. In addition, when the energization is not performed, each blade driving member is held by each holding means at a position where the diaphragm blade member and the shutter blade member are retracted from the exposure opening or the position where the diaphragm blade member enters the exposure opening. Therefore, useless power consumption can be suppressed.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing a state in which the power supply on the camera body side is turned off in the image pickup apparatus of the present invention, and FIG. 2 is a sectional view showing the periphery of the moving magnet. In the figure, 1 is an upper base plate, 2 is an intermediate base plate, and 3 is a base plate. In FIG. An exposure opening AP that forms an imaging optical path is formed in the central portion of these ground planes. Reference numerals 4 and 5 denote shutter blades for opening and closing the exposure opening AP, and the shutter blades 4 and 5 are swingably supported with respect to 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 an aperture forming edge and are in a state of shielding the exposure opening AP when not in use.
[0009]
Next, 6 is a moving magnet for driving the shutter blades 4 and 5 to open and close, FIG. 2 shows a cross section, and FIG. 3 shows an enlarged plan view shown in FIG. The reference numerals of the constituent elements of the moving magnet 6 are not particularly shown in FIG. 1, but can be understood with reference to FIGS. The moving magnet 6 has a coil frame 6b fixed to the inside of a cylindrical casing 6a, and a coil 6c is attached along the longitudinal direction of the coil frame 6b 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 formed to protrude outside the magnet 6e passes through the upper base plate 1 and the middle base plate 2 and is a shutter. The long holes 4a and 5a (see FIG. 1) respectively formed in the blades 4 and 5 are engaged with each other.
[0010]
The operating range of the output pin 6f is restricted by pins 1c and 1d formed of a ferromagnetic material such as iron, which is implanted in the upper base plate 1. In the initial state, the output pin 6f is held in the state shown in FIG. 1 and FIG. 3 with the pin 1c magnetized, but when a positive pulse current is supplied to the coil 6c in this state, the periphery of the coil frame 6b is not shown. 3, a magnetic field having an N pole on the upper side is formed, the magnet 6e rotates counterclockwise about the shaft 6d, and the output pin 6f contacts the pin 1d and stops. Since the output pin 6f is magnetically attached to the pin 1d, the output pin 6f is held in a state where the pin 1d is magnetically attached even if the supply of the positive pulse current is cut off. Further, when a negative pulse current is supplied to the coil 6c from the state where the output pin 6f is magnetically attached to the pin 1d, a magnetic field having an N pole on the lower side in FIG. 3 is formed around the coil frame 6b. 6e rotates clockwise around the shaft 6d, and the output pin 6f comes into contact with the pin 1c and stops. Since the output pin 6f is magnetically attached to the pin 1c, the output pin 6f is held in a state where the pin 1c is magnetically attached even if the supply of the negative pulse current is cut off.
[0011]
In the present embodiment, it is assumed that three types of aperture control, large, medium, and small, are performed, and the fully opened state of the exposure aperture AP corresponds to the large aperture. The medium aperture and the small aperture are obtained by causing the diaphragm blades 7 or 8 to enter the exposure aperture AP, respectively. First, the diaphragm blade 7 corresponding to the medium aperture is supported by a pin 1e planted on the upper base plate 1 in a swingable manner, and an opening 7a corresponding to the medium aperture is formed at the tip of the diaphragm blade 7. Yes. Reference numeral 9 denotes a moving magnet as a drive source for turning the diaphragm blade 7. The configuration of the moving magnet 9 is basically the same as that of the moving magnet 6 already described, and an output pin 9 f is formed on the diaphragm blade 7. Is engaged with the elongated hole 7b. In the present embodiment, the moving magnet 9 rotates clockwise around the shaft 9d until the output pin 9f abuts against the ferromagnetic pin 1f by supplying a positive pulse current. By supplying an electric current, it rotates counterclockwise about the shaft 9d until it abuts against the ferromagnetic pin 1g. The opening 7a formed in the diaphragm blade 7 is substantially concentric with the opening 7a when the output pin 9f of the moving magnet 9 is in contact with the pin 1f.
[0012]
Next, the aperture blade 8 corresponding to the small aperture is swingably supported by a pin 1 h planted on the upper base plate 1, and an opening 8 a corresponding to the small aperture is formed at the tip of the aperture blade 8. ing. Reference numeral 10 denotes a moving magnet as a drive source for turning the diaphragm blade 8. The configuration of the moving magnet 10 is basically the same as that of the moving magnet 6 already described, and an output pin 10 f is formed on the diaphragm blade 8. Is engaged with the elongated hole 8b. In the present embodiment, the moving magnet 10 rotates clockwise around the shaft 10d until the output pin 10f contacts the ferromagnetic pin 1i by supplying a positive pulse current, and a negative pulse is generated. By supplying an electric current, it rotates counterclockwise about the shaft 10d until it abuts on the ferromagnetic pin 1j. The opening 8a formed in the aperture blade 8 is substantially concentric with the opening 8a when the output pin 10f of the moving magnet 10 is in contact with the pin 1i.
[0013]
Next, FIG. 4 is a block diagram of the control system of the present embodiment, 4 and 5 indicate the shutter blades 4 and 5 described above, 7 and 8 indicate the aperture blades 7 and 8 described above, Reference numerals 9 and 10 denote the moving magnets 6, 9, and 10, respectively. Reference numeral 11 denotes a photographing lens, 12 denotes a CCD as an imaging means, 13 denotes an image signal processing circuit 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. Each computer is shown. Reference numeral 17 denotes a shutter drive circuit that supplies a drive signal to the moving magnet 6 for driving the shutter, 18 denotes an aperture drive circuit that supplies a drive signal to the moving magnet 9 and the moving magnet 10 for driving the aperture, and 19 denotes charge storage of the CCD 12. And an electronic shutter control circuit for controlling charge emission.
[0014]
Next, the operation of the present embodiment will be described in detail with reference to the above items, the flowchart of FIG. 5, the time chart of FIG. 6, and the plan views showing the state changes of FIGS. First, in the initial state, the mechanism is in the state shown in FIG. The program starts when the main switch 15 is turned on, 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. To supply. (Steps S2, S3)
[0015]
When a positive pulse signal is supplied to the moving magnet 6, the output pin 6f rotates about the shaft 6d counterclockwise until it contacts the pin 1d. When the output pin 6f comes into contact with the pin 1d, the output pin 6f magnetizes the pin 1d, so that the position of the output pin 6f is maintained even in the non-energized state after the positive pulse current falls. Thus, when the output pin 6f rotates counterclockwise from the state shown in FIG. 1, since the pin 6f engages the long holes 4a and 5a, the shutter blade 4 rotates counterclockwise around the shaft 1a, The shutter blade 5 rotates clockwise about the shaft 1b to open the exposure opening AP. 7 and 8 show a state where the shutter blades 4 and 5 open the exposure opening AP.
[0016]
Now, since the CCD 12 has already begun to operate, when the shutter blades 4 and 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 the microcomputer 16. Added to. The microcomputer 16 measures the field luminance based on 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). When the release switch 14 is turned on, the process branches according to the aperture value calculated in step S4 (step S9).
[0017]
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). The moving magnet 9 has an output pin 9f centered on the shaft 9d. Since the pin 1f is turned to the right until it abuts against the pin 1f, and the pin 1f is magnetized, the right-handed position is maintained even in a non-energized state where a positive pulse current falls. As the moving magnet 9 rotates clockwise, the diaphragm blade 7 also rotates clockwise about the shaft 1e, and the opening 7a narrows the exposure opening AP to the middle diaphragm. FIG. 7 shows a state in which the opening 7a narrows the exposure opening AP to the middle stop in this way. When the aperture value to be used is a small aperture, the microcomputer 16 controls the aperture drive circuit 18 to supply a positive pulse current to the moving magnet 10 (step S11). The moving magnet 10 has an output pin 10f with a shaft 10d. Since the pin 1i is rotated clockwise until it abuts on the pin 1i and the pin 1i is magnetized, the right-handed position is maintained even in the non-energized state where the positive pulse current falls. As the moving magnet 10 rotates clockwise, the aperture blade 8 also rotates clockwise about the axis 1h, and the opening 8a narrows the exposure aperture AP to a small aperture. FIG. 8 shows a state in which the opening 8a narrows the exposure opening AP to a small stop in this way. Further, when the aperture value to be used is a large aperture, the aperture is not narrowed down, and the process immediately proceeds to step S12. That is, in this case, the aperture value is the same as the aperture of the exposure aperture AP.
[0018]
When the aperture value is determined in this way, the microcomputer 16 controls the electronic shutter control circuit 19 to release the accumulated charge of the CCD 12 (step S12). Then, the CCD 12 starts accumulating charges again from the time when the discharge operation is completed. Therefore, this timing is the start timing of the effective exposure time. Since the appropriate 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 has elapsed after releasing the accumulated charge of the CCD 12 in step S12. Then, a negative pulse current is supplied to the moving magnet 6 (step S14). By supplying a negative pulse current to the moving magnet 6, the output pin 6f rotates around the shaft 6d in the clockwise direction until it contacts the pin 1c. When the output pin 6f comes into contact with the pin 1c, the output pin 6f magnetizes the pin 1c, so that the position of the output pin 6f is maintained even in a non-energized state after the negative pulse current falls. In this way, when the output pin 6f rotates clockwise from the state shown in FIG. 7 or FIG. 8, the shutter blade 4 rotates counterclockwise about the shaft 1a and the shutter blade 5 rotates clockwise about the shaft 1b. Shield AP. Therefore, in the case of large aperture photography in which the aperture diameter is determined by the exposure aperture AP, the total area of the hatched portion ABC in FIG. 6, the total area of the hatched portion BC in FIG. 6 corresponds to the effective exposure amount, and in the case of small aperture photography in which the aperture diameter is determined by the aperture 8a of the aperture blade 8, the area of the hatched portion C in FIG. It will be equivalent.
[0019]
When the shutter blades 4 and 5 block the exposure aperture AP in this way, the microcomputer 16 controls the image signal processing circuit 13 to capture the output of the CCD 12 (step S15), and the image signal processing circuit 13 receives the image signal, for example. One writing operation is completed in a storage device such as an external memory card. When one photographing operation is completed in this way, the microcomputer 16 prepares for photographing the next frame as follows. That is, the microcomputer 16 determines whether or not the diaphragm blades 7 or 8 are used in step S16. When the diaphragm blade 7 is used, a negative pulse current is applied to the moving magnet 9 and when the diaphragm blade 8 is used, a negative pulse current is applied to the diaphragm magnet 7 or the diaphragm blade 8 respectively. 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 wait for the release switch 14 to be turned on in step S8. Needless to say, the moving magnets 9 and 10 maintain the state shown in FIG. 1 by the magnetic force between the output pins 9f and 10f and the pins 1g and 1j even after the negative pulse current is stopped. Further, when it is detected in step S5 that the power switch 15 is turned off while waiting for the release switch 14 to be turned on in this way, the shutter drive circuit 17 is controlled in step S6 to cause the moving magnet 6 to be negative. A pulse current is applied, and the shutter blades 4 and 5 are driven to close to complete the exposure operation. The control operation after the power switch 15 is turned off is executed with power supplied from a capacitor circuit such as a capacitor (not shown).
[0020]
【The invention's effect】
As described above, according to the present invention, the diaphragm blade member and the shutter blade member are held in the first position retracted from the exposure opening and in the second position entering the exposure opening. Since the shutter can be held without a complicated mechanism, the shutter blade member can be held at the second position when the power is turned off to protect the image pickup means, and the operation of the release switch is waited after the power is turned on. When the shutter blade member is held in the first position, the liquid crystal finder or the like can be used by holding the shutter blade member in the first position, and the exposure opening is closed by driving the shutter blade member from the first position to the second position. Thus, it is possible to effectively cope with an increase in the number of pixels. The power consumption associated with driving the blades occurs only when the position of each blade is reversed and does not occur during holding. Therefore, a large amount of power is required for driving the liquid crystal finder and writing image data. In an imaging apparatus such as an electronic still camera, power consumption as a whole can be reduced, and the number of frames that can be shot can be increased. Further, according to the present invention, since the rotation shaft of the shutter blade driving means is arranged on a substantially straight line passing through the support shafts of the two shutter blade members, the shutter blade member can be operated with a stable driving force. Can do.
[Brief description of the drawings]
FIG. 1 is a plan view of an imaging apparatus according to an embodiment of the present invention in an initial state.
2 is a cross-sectional view of the moving magnet 6 shown in 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;
6 is a time chart showing the operation timing of the control system shown in FIG. 4;
FIG. 7 is a plan view of the embodiment shown in FIG.
FIG. 8 is a plan view of the embodiment shown in FIG. 1 in a small aperture state.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Top plate 1c, 1d, 1f, 1g, 1i, 1j Pin 4, 5 Shutter blade 6 Moving magnet 6f Output pin 7 Diaphragm blade 7a for middle diaphragm 8 Diaphragm blade 8a for small diaphragm 9 Open magnet 9f Output pin 10 Moving Magnet 10f Output pin 11 Lens 12 CCD
16 Microcomputer AP Exposure opening

Claims (1)

A photographing optical system that forms an image of incident light on a predetermined imaging plane;
Imaging means disposed on the imaging plane;
At least two ground planes each having an exposed opening, the exposed opening being disposed in the optical path of the incident light;
Located between the ground planes and rotatably mounted on one of the ground planes and operating between a first position retracting from the exposure opening and a second position entering the exposure opening A diaphragm blade member capable of forming an opening smaller than the exposed opening;
A first position disposed between the ground planes, rotatably attached to one of the ground planes and retracted from the exposure opening by rotating; and a second position entering the exposure opening; A shutter blade member actuated between,
It has a rotatable magnet, and when the drive current is supplied, the magnet is turned to operate the diaphragm blade member between the first position and the second position, and no drive current is supplied. A diaphragm blade driving means for holding the magnet so as not to rotate,
A rotating magnet is provided, and when the drive current is supplied, the magnet is turned to operate the shutter blade member between the first position and the second position, and the shutter is used at the end of photographing. actuating the blade member from said first position to said second position, and the shutter blade driving means for holding so as not to pivot the magnet when the drive current is not Tei is supplied,
The aperture value and shutter speed are calculated from the field luminance, and the supply of drive current to each of the drive means is controlled according to the calculation result. When the power is turned on, the shutter blade member is used by the shutter blade drive means. Is operated from the second position to the first position and the power is turned off to operate from the first position to the second position. When the shutter is released during photographing, the position of the aperture blade member is determined based on the calculation result. to release the charge accumulated in said image pickup means from have your Te, the said shutter blade member and the shutter speed has elapsed actuates to the second position, then actuates the shutter blade member to the first position An image pickup apparatus comprising the control means as described above.

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