JP2007025357A - Camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a failure such as re-exposure caused by shutter-bound after the shutter is closed, with less power consumption, while maintaining a high-speed shutter operation, dispensing with a spacial elastic member. <P>SOLUTION: The camera is provided with a shutter control means equipped with a driving circuit for opening/closing an exposure shutter, and for controlling the closing operation of the shutter with first driving power which is supplied to a shutter actuator in a period until the shutter is nearly closed after the start of closing, and with second driving power smaller than the first driving power, which is supplied to the shutter actuator so as to stabilize the shutter movement in a fixed period after the shutter is nearly closed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a camera provided with a shutter mechanism. In particular, the present invention relates to a camera provided with a shutter mechanism configured to prevent and control re-exposure due to rebound of a shutter body. Furthermore, the present invention relates to a shutter device for a camera configured to be able to control rebound of a shutter body with power saving.

  The conventional exposure shutter device can obtain an accurate exposure time by suppressing the bounce of the shutter body. An example of such an exposure shutter device uses an elastic member, and a roller is provided which is disposed away from the elastic plate by a torsion coil spring in a state where the shutter main body is not in contact with the movable plate. In a state where the shutter main body is at each position where the shutter body is opened and closed, the movable plate is pressed against the elastic plate while moving the roller. Thereby, the kinetic energy of the shutter body is absorbed, and the reaction of the shutter body is suppressed. In such an exposure shutter device, the standing portion of the movable plate is in contact with the reaction portion of the shutter main body, which also suppresses the reaction of the shutter main body (see, for example, Patent Document 1).

  In another example, in a conventional shutter device, the shutter drive current is usually constant from the start of shutter operation until it stops, but the shutter drive current is increased near the closed position compared to the open position. Thus, a proposal has been made to prevent rebound by electrically controlling the holding force after closing to increase (see, for example, Patent Document 2).

In another example, when the operating speed of the shutter blade is measured and it is predicted that the shutter blade will hit the open end, a proposal has been made to drive control that slows down the operating speed of the shutter blade before hitting (for example, (See Patent Document 3).
JP-A-7-209770 (pages 2 to 4, FIG. 1) JP 2004-219740 A Japanese Patent Application Laid-Open No. 2003-075886 JP-A-2004-54232

  Therefore, an exemplary object of the present invention is to prevent re-exposure due to shutter bound after closing with power saving while maintaining a high-speed shutter operation without using a special elastic member.

  In the conventional example disclosed in Patent Document 1, in addition to using an expensive elastic member, the number of parts constituting the shutter mechanism is large, and the shutter structure is complicated, but the contact with the stopper is complicated. The rebound may cause a rebound operation, and the exposure path opening / closing operation may become unstable.

  In the conventional example disclosed in Patent Document 2, since the shutter closing operation power is less than the holding power after the shutter is closed, there is a concern that the shutter speed may be suppressed, or the holding time after the shutter is closed with a large amount of power. Concerns about power consumption problems arise because it is necessary.

  Further, the conventional example disclosed in Patent Document 3 requires a sensor for measuring the operating speed of the shutter blades, further requires many electronic components such as a contact prediction calculation circuit, and sets the shutter speed before the contact. Since it decelerates, it is not suitable for speeding up the shutter.

  The present invention has been made paying attention to the above points, and re-exposure by shutter bound after closing is performed while maintaining a high-speed shutter operation without using complicated mechanical parts and special elastic members. It is an object of the present invention to provide a camera that can prevent the rush current accompanying the shutter operation as much as possible, and to save electricity during a period of stabilization after the shutter is closed.

In order to achieve the above object, the camera of the present invention
First, a drive circuit for opening and closing the exposure shutter is provided,
A shutter actuator that stabilizes the movement of the shutter for a certain period of time after being substantially closed with a first driving power supplied to the shutter actuator in a period from the beginning of closing to substantially closing and a driving power less than the first driving power. And a shutter control means for controlling the closing operation of the shutter with the second driving power supplied to.

Secondly, a drive circuit for opening and closing the exposure shutter is provided,
It is characterized by comprising shutter control means for controlling with shutter operating power having different closing direction driving power and opening direction driving power supplied to the shutter actuator.

  Further objects and other features of the present invention will be made clear by the preferred embodiments described below with reference to the accompanying drawings.

  According to the present invention, there is provided an exposure shutter device that prevents re-exposure due to shutter bouncing after closing while maintaining a high-speed shutter operation without using complicated mechanical parts or special elastic members. Can do. Furthermore, since the rush current accompanying the shutter operation is suppressed as much as possible, it is possible to save electricity during the period of stabilization after the shutter is closed.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

  The shutter mechanism unit according to the present invention and a shutter driving device including a shutter driving control circuit are mounted on, for example, an interchangeable lens unit 110a having an imaging optical system of an imaging camera unit 150 having a still image shooting mode as shown in FIG. Is done.

  As described above, the configuration that can be separated into the camera unit 150 and the lens unit 110a is, for example, a configuration of a coupling method called a bayonet mount, and is adopted in a single-lens reflex camera, a video camera, or the like. The camera unit 150 and the lens unit 110a have their electrical contacts 171 and 172 to be electrically connected when both units are coupled by the bayonet mount method.

  Specifically, in addition to the circuits provided in the camera unit 150 shown in FIG. 1, the camera communication circuit 156 to which the output of the camera control microcomputer 155 is supplied and output thereto, the recording mode selection information 165, A lens communication circuit 118 is provided to which an output of shutter instruction information 157 including exposure amount information is supplied and input thereto.

  The camera communication circuit 156 is provided in the camera unit 150 including the image sensor 151, the camera signal processing circuit 152, and the camera microcomputer 155, and the lens communication circuit 118 is provided in the lens unit 110a including other circuits. Further, the camera communication circuit 156 and the lens communication circuit 118 are configured to transmit information to each other via their contacts 171 and 172 when the camera unit 150 and the lens unit 110a are coupled. Each of the camera communication circuit 156 and the lens communication circuit 118 is connected to, for example, a one-chip microcomputer, and transmits information for a still image shutter as one of the information transmission items. It is made to do.

  Further, in the camera unit 150, shutter information 157 corresponding to still image shooting or moving image shooting selected by the recording mode selection switch 165 is transferred to the lens unit 110a via the camera communication circuit 156 at a predetermined timing.

  On the other hand, in the lens unit 110a, the recording mode information 165 and shutter information 157 transferred from the camera unit 150 are received by the lens communication circuit 118, and the diaphragm 114 operation and the shutter 113 operation are executed via the lens control microcomputer 117.

  Transfer of shutter information 157 and the like (including exposure information) from the camera unit 150 to the lens unit 110a as described above is synchronized with, for example, a vertical synchronization signal of a video signal via the camera communication circuit 156 and the lens communication circuit 118. It is performed at the predetermined timing. Note that the camera communication circuit 156 and the lens communication circuit 118 may have any electrical data transmission function such as serial communication.

  Hereinafter, each component will be specifically described.

(Recording mode selection switch 165)
A selection switch provided on the exterior of the imaging device 150 or the like for recording a moving image as a moving image or recording a still image as a still image. The recording mode switch 160 is not limited to the camera exterior 150, but may be the lens unit exterior 110.

(Movie recording 161)
The recording compression-coded signal generated by the recorder process 154 is recorded as a moving image in a desired recording format, for example, on a DV tape, HDD, or DVD medium.

(Still image recording 162)
The recording compression-coded signal generated by the recorder process 154 is recorded as a still image in a desired recording format, for example, on an SD card, a CF card, or a card type HDD medium.

(Image sensor 151)
An image sensor 151 having a CCD or CMOS structure provided with a color filter that photoelectrically converts image light guided from the imaging optical system of the lens unit 110a, and filters for each color (for primary colors, R, G, and B) are arranged in a matrix. Not only the single-plate image sensor 151, but also a three-single-plate image sensor 151 in which the R, G, and B filters are independent of each other. The horizontal line charge readout method is not limited to the progressive (30P) method, but may be an interlace (60i) method.

(Amplification circuit AFE152)
While amplifying the charge signal from the image sensor 151, the reference output level (OB value) between the pixels is offset and aligned, and A / D conversion is performed to digitize the signal of each pixel.

(Camera signal processing circuit 153)
The camera signal processing circuit 153 includes a frame memory such as an SRAM, and performs image generation processing corresponding to a moving image or a still image from the digital image signal obtained by the amplification circuit AFE152 via the imaging optical system and the imaging element 151. . In the case of making a moving image signal, for example, a video signal (video signal) conforming to the NTSC format is generated. When a still image video signal is used, the still image video information is temporarily stored in a frame memory such as an SRAM to generate a still image signal.

(Camera microcomputer 155)
The shooting value of the recording mode selection switch 165 and the shooting mode dial 167 is detected, and the evaluation value related to the shooting light or the above shooting is set so that the shooting light according to the moving image mode or the still image mode is incident on the image sensor 151. Outputs the recording setting state to the camera communication circuit 156. When the still image mode is set, shutter information such as shutter timing and exposure conditions is output to the camera communication circuit 156. Further, the selection result of the recording mode selection switch 165 is output to the recorder process 154.

(Shooting mode dial 167)
Exposure / shutter speed parameters suitable for the shooting conditions of the subject set by the photographer's intention. Aperture priority AV mode, shutter speed priority Tv mode, M mode for manually setting exposure and shutter speed, exposure and shutter P mode for optimally automatically setting the speed, and green mode for completely automating other operation corrections such as autofocus.

(Recorder process 154)
Upon receipt of the video signal (video signal) generated by the camera signal processing circuit 153, a recording compression encoded signal is generated, and conforms to, for example, the DV tape standard or the SD card standard according to the selection result of the recording mode selection switch 165. Record on the media in the desired recording format.

  The camera unit 150 is configured as described above. On the other hand, the lens unit 110a has the following configuration.

(Imaging optical systems 111, 112, 115, 116)
This is a four-unit variable magnification optical system that forms a photographic subject image on the image sensor 151. The focal length is changed by the relative movement of the second group lens 112 and the fourth group lens 116, and the focus is adjusted by the movement of the fourth group lens 134. Match.

(Actuators 121, 127)
The actuator 121 is a two-phase stepping motor 121 or the like that moves the second group lens 112, and is driven by a PWM drive driver or the like having an H-bridge configuration of a transistor. The actuator 127 is a two-phase boil coil (VCM) 127 or the like that moves the fourth group lens 134, and is driven by a PWM drive driver or the like having an H-bridge configuration like the stepping motor 121.

(Diaphragm mechanism 114, 125)
The diaphragm mechanisms 114 and 125 include a diaphragm 114 and a diaphragm actuator 125. The diaphragm 114 is composed of six diaphragm blades and a ground plate for holding the diaphragm blades, and a galvanometer coil (IG) is used as the diaphragm actuator 125. The amount of light on the image on the image sensor 151 is accurately adjusted by the iris diaphragm of six diaphragm blades.

(Shutter mechanism 113, 123)
FIG. 8 shows an exploded perspective view of the shutter mechanism including the shutter 113 and the shutter actuator 123. It has two shutter blades, and includes a ground plate that holds the shutter blades, a coil 123 that drives the shutter blades in one phase, a magnetized rotor, and a stator made of a magnetic material. Moreover, even if the power supply to the coil 123 is released, the coil 123 can be held at the open position or the closed position by the magnetic force. The detailed description of such a shutter mechanism 113.123 is omitted because an example such as Patent Document 4 is disclosed.

  In the moving image mode, the shutter position is held at the opening position, and in the still image mode, the shutter information 157 from the camera control unit microcomputer 155 is communicated, and the amount of light is reduced by the diaphragm 114 according to the exposure condition instructed from the camera control unit 155. Operate the shutter while adjusting.

  Next, the features of the present invention will be described with reference to the flowchart of FIG. 3 and the shutter drive circuit block of FIGS. 2 and 6 and the characteristic diagrams of FIGS.

  The camera control microcomputer 155 detects the position of the recording mode selection switch 165 provided on the exterior surface of the camera unit 150 of the imaging apparatus, so that the moving image recording mode for moving image recording / shooting or the still image for shooting still image recording / shooting is performed. The recording mode is determined 121 from the camera communication circuit 156 via the lens communication circuit 118 in the lens unit 110a or 110b (step S302).

  If the result of determination in step S302 is that it is in the moving image recording mode, in step S321, the shutter 113 is opened and held at the open position.

  Here, details of the opening operation will be described. FIG. 2 shows a first example of the shutter driving device.

  When the shutter information 120 is determined to be opened by the shutter information 120, the lens control microcomputer 117 energizes the coil 123 via the drive driver 124 in the opening direction of the shutter 113, thereby opening the shutter 113. The driving current at this time is driven by a total value (for example, 300 mA) of a predetermined constant current value set by the setting constant (resistance value) 211 and the setting constant (resistance value) 212 by turning off the current switch 233. .

  FIG. 5 shows a characteristic diagram of the opening of the shutter 113. FIG. 6 is a characteristic diagram when the energization period is on the horizontal axis and the light amount change amount is on the vertical axis, showing a state in which the T53 light amount change period is open. T50a indicates when the open end is struck, and for the purpose of alleviating the bounce generated by the struck impact, the shutter 113 is continuously opened for a certain period after the T54 drive period is opened after the open end is struck. During the shutter 113 opening drive period at this time, the lens control microcomputer 117 reads data stored in the memory 119 in advance.

  If the result of determination in step S302 is that it is still image recording mode, in step S303, the shutter 113 timing is awaited until the shutter information 120 is obtained.

  When the shutter information 120 is obtained in step S304, the shutter 113 is closed. In step S306, the closing operation is continued for a certain period even after the shutter 113 is fully closed.

  Here, details of the closing operation will be described. In FIG. 2, in the shutter driving device, when the shutter 113 is determined to be closed by the shutter information 120, the lens control microcomputer 117 energizes the coil 123 via the drive driver 124 in the closing direction of the shutter 113, thereby closing the shutter 113. To do.

  The driving current at this time is the sum (for example, 300 mA) of a predetermined constant current value set by the setting constant (resistance value) 211 and the setting constant (resistance value) 212 when the current switch 233 is turned on, and the shutter 113. It is driven for a period until it is fully closed.

  Thereafter, after the shutter 113 is closed, the current switch 233 is turned off, and the shutter 113 is driven for a period after the shutter 113 is closed with a predetermined constant current value (for example, 100 mA) of only the set constant (resistance value) 211.

  FIG. 4 is a characteristic diagram of the shutter 113 closing. As in FIG. 5, a characteristic diagram when the energization period is on the horizontal axis and the light amount change amount is on the vertical axis shows how the T41 and T42 light amount change periods are closed. T40a indicates when the closed end is abutted, and for the purpose of preventing re-exposure due to the bounce generated by the abutting impact, the shutter 113 is kept closed for a certain period after the T46 drive period is closed.

  The lens control microcomputer 117 reads the shutter 113 closing drive period at this time and the driving period after the shutter 113 is closed from the data stored in the memory 119 in advance.

  In step S308, when the exposure operation from the opening of the shutter 113 to the closing (including the stable period of re-exposure prevention after the shutter 113 is fully closed) is completed, the shutter 113 is opened again and held at the opening position.

  FIG. 6 shows a shutter 113 driving circuit when multistage control of the shutter 113 opening / closing operation is performed as a modification of the embodiment.

  FIG. 7 is a characteristic diagram for further preventing the re-exposure by further dividing the drive period after the shutter 113 is fully closed.

  FIG. 9 shows a flowchart for control while detecting the shutter position.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

The block diagram which shows the structure of the imaging device by which the shutter apparatus concerning this invention is mounted. The block diagram which shows the 1st structure of the shutter apparatus concerning this invention. The flowchart which shows the 1st operation | movement of the shutter apparatus concerning this invention. First characteristic diagram showing closing operation of shutter device according to the present invention FIG. 6 is a characteristic diagram showing the opening operation of the shutter device according to the present invention. The block diagram which shows the 2nd structure of the shutter apparatus concerning this invention. Second characteristic diagram showing closing operation of shutter device according to the present invention The perspective view which shows the mechanism structure of the shutter apparatus concerning this invention. The flowchart which shows the 3rd operation | movement of the shutter apparatus concerning this invention. First characteristic diagram showing closing operation of a conventional shutter device Second characteristic diagram showing closing operation of conventional shutter device

Explanation of symbols

113 Shutter 117 Lens control microcomputer 118 Lens communication circuit 119 Memory 120 Lens shutter information 155 Camera control microcomputer 156 Camera communication circuit 157 Camera shutter information 165 Recording mode selection switch

Claims (2)

A drive circuit for opening and closing the exposure shutter;
A shutter actuator that stabilizes the movement of the shutter for a certain period of time after being substantially closed with a first driving power supplied to the shutter actuator in a period from the beginning of closing to substantially closing and a driving power less than the first driving power. A shutter control means for controlling the closing operation of the shutter with the second driving power supplied to the camera. A drive circuit for opening and closing the exposure shutter;
A camera comprising shutter control means for controlling with shutter operating power having different closing direction driving power and opening direction driving power supplied to a shutter actuator.

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