JP2005331828A - Digital single-lens reflex camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital single-lens reflex camera capable of minimizing operating sound of a shutter in course of release, and shock caused by the operation. <P>SOLUTION: In course of the observation of a subject, a luminous flux entering via a lens unit 51 is reflected by the main mirror 70 of an electret shutter unit 21 and causes to form image onto a focusing screen 71. Further, an erect non-reverse image is observed by a photographer through a pentaprism 72 and a magnifier lens 73. When a photographing operation takes place, a shutter curtain in the electret shutter unit 21 is driven and an aperture is fully opened. As a result, the subject luminous flux entering via the lens unit 51 is transmitted through the electret shutter unit 21 and led to an imager 42. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a digital single-lens reflex camera, and more particularly to a digital single-lens reflex camera in which a shutter device using the principle of an electrostatic actuator is provided in a photographing optical path.

  In general, in the case of a single-lens reflex type camera (hereinafter simply abbreviated as a single-lens reflex camera), a focal plane shutter is disposed on the front surface of a film or an image sensor so that the exposure amount is adjusted. . In recent years, a focal plane shutter of the type in which the front curtain and the rear curtain are formed of a plurality of lightweight metal blades and each is driven by a spring force is generally known for speeding up. .

  A general single-lens reflex camera employs a quick return method in which a first reflecting surface that guides a light beam from a subject to a viewfinder mechanically retracts when released.

  As a mirror of such a single-lens reflex camera, a single motor rotates in the same direction to move the movable mirror from a position where it enters the photographing optical path to a position where the exposure is retracted, and vice versa. In addition, there is known a technique for driving a shutter from a charge state to a charge release state and driving from the charge release state to the charge state (see, for example, Patent Document 1).

Further, the electromagnet is deactivated based on the input of the retracted signal, and the shutter charge member is smoothly moved along the shutter charge cam, so that the shutter blades are slowly opened and closed to release the charged state of the focal plane shutter. A lens retractable single-lens reflex camera is known (for example, see Patent Document 2).
Japanese Patent Publication No. 7-27156 JP-A-5-173246

  However, in the single-lens reflex camera having the above-described configuration, an impact sound accompanying the operation of the shutter, a motor sound of the power source, and the like are generated. In addition, the shutter operating sound is similarly produced by an impact sound at the end of travel of the shutter curtain, a motor sound of the power source, and the like. For this reason, there has been a problem that the camera cannot be used at the time of shooting under conditions where it is not desired to generate such sound.

  In addition, there is a problem that camera shake may occur due to a shock generated by an impact of the operation of the shutter.

  Accordingly, the present invention has been made in view of the above circumstances, and an object thereof is to provide a digital single-lens reflex camera capable of minimizing the shutter operating sound at the time of release and the shock generated by the operation.

  That is, according to the first aspect of the present invention, in a digital single-lens reflex camera having an electrostatic shutter device that drives a shutter curtain using an electrostatic force, a semi-transmission is performed on the subject light incident side of the electrostatic shutter device. A member having characteristics is arranged, the light reflected by the member is guided to a finder optical system for a subject image, and the transmitted light is guided to an image sensor.

  According to a second aspect of the present invention, in the first aspect of the present invention, the member is arranged in parallel with the electrostatic shutter device.

  According to a third aspect of the present invention, in the first aspect of the present invention, the shutter curtain of the electrostatic shutter device travels in parallel with the member.

  According to a fourth aspect of the present invention, in the first aspect of the present invention, the member is a beam splitter prism.

  According to a fifth aspect of the present invention, in the first aspect of the present invention, an antireflection curtain is formed on a surface of the electrostatic shutter device on which subject light is incident.

  According to a sixth aspect of the present invention, in a digital single-lens reflex camera having an electrostatic shutter device that drives a shutter curtain using electrostatic force, a beam splitter prism that separates a subject luminous flux into a finder optical system side and an image sensor side. And the electrostatic shutter is integrally disposed on the exit surface of the beam splitter prism on the imaging element side.

  A seventh aspect of the present invention is the electrostatic shutter device according to the sixth aspect, wherein the electrostatic shutter device applies a voltage to the electrode member having a plurality of driving electrodes on the surface and the driving electrode. And a moving member that moves relative to the electrode member in response to the electrostatic force generated at the time, and the moving member is sandwiched between the imaging element side emission surface of the beam splitter prism and the electrode member. It is comprised by these.

  The invention according to claim 8 is the invention according to claim 6, wherein the shutter curtain of the electrostatic shutter device travels in parallel with the exit surface of the beam splitter prism.

  According to a ninth aspect of the present invention, in the sixth aspect of the present invention, an antireflection curtain is formed on a surface on which subject light is incident of the electrostatic shutter device.

  According to a tenth aspect of the present invention, there is provided a finder optical system for observing a subject image via a photographing lens, an imaging element for converting a subject luminous flux incident via the photographing lens into an electrical signal, the photographing lens, and the above In the digital single-lens reflex camera, which is disposed on the optical path between the imaging element and drives the shutter curtain using electrostatic force, the electrostatic shutter apparatus is configured to A semi-transparent member disposed on the incident side, and guides a subject light beam incident through the photographing lens and reflected by the semi-transmissive member to the finder optical system, and transmits through the semi-transmissive member. The subject light flux is guided to the image sensor.

  According to an eleventh aspect of the present invention, in the invention according to the tenth aspect, the semi-transmissive member is arranged in parallel with a shutter curtain of the electrostatic shutter device.

  According to a twelfth aspect of the invention, in the invention of the tenth aspect, the shutter curtain of the electrostatic shutter device travels in parallel with the semi-transmissive member.

  The invention described in claim 13 is the invention described in claim 10, wherein the semi-translucent member is a beam splitter prism.

  According to a fourteenth aspect of the invention, in the tenth aspect of the invention, an anti-reflection curtain is formed on the surface of the electrostatic shutter device on which subject light is incident.

  According to a fifteenth aspect of the present invention, there is provided a finder optical system for observing a subject image through a photographing lens, an imaging element for converting a subject luminous flux incident through the photographing lens into an electric signal, the photographing lens, and the above In a digital single-lens reflex camera comprising: an electrostatic shutter device that is disposed on an optical path between the imaging element and drives a shutter curtain using electrostatic force; The apparatus further comprises a beam splitter prism which is separated to the image pickup device side and in which the electrostatic shutter device is integrally arranged on the exit surface of the image pickup device side.

  According to a sixteenth aspect of the present invention, in the electrostatic shutter device according to the fifteenth aspect of the invention, the electrostatic shutter device applies a voltage to the electrode member having a plurality of driving electrodes on the surface and the driving electrode. And a moving member that moves relative to the electrode member in response to the electrostatic force generated at the time, and the moving member is sandwiched between the imaging element side emission surface of the beam splitter prism and the electrode member. It is comprised by these.

  According to a seventeenth aspect of the invention, in the fifteenth aspect of the invention, the shutter curtain of the electrostatic shutter device travels parallel to the exit surface of the beam splitter prism.

  According to an eighteenth aspect of the present invention, in the invention according to the fifteenth aspect, an antireflection curtain is formed on a surface of the electrostatic shutter device on which a subject luminous flux is incident.

  According to a nineteenth aspect of the present invention, there is provided a finder optical system for observing a subject image through a photographing lens, an imaging element for converting a subject luminous flux incident through the photographing lens into an electric signal, the photographing lens, and the above In the digital single-lens reflex camera, which is disposed on the optical path between the imaging element and drives the shutter curtain using electrostatic force, the electrostatic shutter apparatus is configured to And a semi-transparent member disposed on the incident side, and when the shutter curtain is in a position to block the optical path of the subject luminous flux, the subject luminous flux incident through the photographing lens is reflected to reflect the finder. When guided to an optical system and the shutter curtain is at a position where the optical path of the subject luminous flux is opened, the subject luminous flux transmitted through the semi-transmissive member is guided to the imaging element.

  According to a twentieth aspect of the invention, in the invention of the nineteenth aspect, the semi-transmissive member is arranged in parallel with a shutter curtain of the electrostatic shutter device.

  The invention according to claim 21 is the invention according to claim 19, wherein the shutter curtain of the electrostatic shutter device travels in parallel with the semi-transmissive member.

  A twenty-second aspect of the invention is the invention according to the nineteenth aspect, wherein the semi-translucent member is a beam splitter prism.

  According to a twenty-third aspect of the invention, in the nineteenth aspect of the invention, an antireflection curtain is formed on a surface on which subject light is incident of the electrostatic shutter device.

  According to the present invention, it is possible to provide a digital single-lens reflex camera capable of minimizing the shutter operating sound at the time of release and the shock generated by the operation.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the driving principle of the electrostatic shutter device according to the present invention will be described with reference to FIGS.

  The shutter device basically includes a stator 1 and a mover 2, and the mover 2 is configured to be movable in the left-right direction in FIGS. 1A and 1B with respect to the stator 1. Has been. The stator 1 is provided with an opening 3 for guiding a light image from the subject to an image sensor (not shown). Further, a plurality of strip-like extended drive electrodes 4 are arranged in parallel at predetermined intervals on the stator 1 in a direction orthogonal to the moving direction of the moving element 2.

  The mover 2 includes a plurality of permanent-polarized extended derivatives (hereinafter referred to as electrets) 5 described later.

  In such a configuration, when a frequency voltage is applied to the drive electrode 4, an attractive force or a repulsive force is generated between the drive electrode 4 and the above-described electret. Move relative. Therefore, if the movable element 2 is movable so as to open or shield the opening 3 of the stator 1, a shutter device can be configured thereby.

  FIG. 1A shows a state where the shutter is open, and FIG. 1B shows a state where the shutter is closed. Note that the opening 3 is not necessarily required in the stator 1, and the region where the driving electrode 4 is not provided as shown in FIG. 1A using the stator 1 as a transmissive member, that is, a transmissive region. May be formed. Hereinafter, such a region through which the subject luminous flux passes is referred to as an opening for convenience. In addition, the shutter device according to this configuration is referred to as an electret shutter.

  FIG. 2 is a diagram schematically showing a cross section of such an electret shutter and a drive circuit for the electret shutter.

  In the electret shutter 7, voltage signal lines from the drive circuit 10 are connected to the drive electrodes 4 arranged in parallel with the stator 1. A four-phase voltage signal is applied to these voltage signal lines. Therefore, the same voltage signal is applied to each of the four drive electrodes 4. In FIG. 2, the voltage signals are distinguished by attaching the symbols A, B, C, and D to the drive electrode 4.

  The mover 2 is provided with a plurality of permanent-polarized derivatives (electrets) 5 on the surface facing the stator 1.

  This figure is only a schematic diagram, and the number and arrangement interval of electrodes and electret parts in an actual electret shutter are the size of the shutter, the area of the opening, the polarity of the electret part, the arrangement form, the shutter. It is appropriately determined depending on various factors such as drive resolution and maximum shutter speed required for the apparatus. In addition, in the case of this electret shutter, electret portions having positive and negative polarities are alternately arranged, but this can be realized with only one of the polarities.

  The left side of FIG. 2 shows the configuration of the drive circuit 10 for generating a voltage signal applied to the electret shutter 7 together with the configuration of the electret shutter 7 described above.

  The rectangular wave train (drive pulse signal) generated by the pulse generation circuit 12 is supplied to the phase shifter 13 and the booster circuit 14. In the booster circuit 14, the input rectangular wave train is boosted to about 100 V, is branched into voltage signals having two polarities, and is supplied to the drive electrodes 4 A and 4 C. On the other hand, the rectangular wave train input to the phase shifter 13 has a waveform delayed by 90 °, and is then input to the booster circuit 14 to form two rectangular wave trains similar to those described above, and is applied to the drive electrodes 4B and 4D. Supplied.

  FIG. 3 is a timing chart showing an example of a voltage signal sequence created by the drive circuit 10 and applied to the drive electrodes 4A to 4D. Among these, FIG. 3A is a drive electrode 4A, FIG. 3B is a drive electrode 4B, FIG. 3C is a drive electrode 4C, and FIG. 3D is a timing chart of the drive electrode 4D.

  The voltage states of the drive electrodes 4A to 4D are such that the four states from time t1 to t4 change repeatedly as time elapses.

  4A to 4D are views for explaining the operation of the electret shutter 7 described above. 4 (a) to 4 (d), the right direction in the figure is the traveling direction of the electret, and the positive (plus) electret (electretized portion) 5a is located on the rear side (left side), and the front side (right side). It is assumed that negative (negative) electrets (electretized sites) 5b are arrayed on each other.

  FIG. 4A shows the voltage state (polarity) of the electret and the drive electrode 4 immediately after switching to the time t1 shown in FIG.

  In this state, the positive electret 5a receives a repulsive force from the drive electrode A (positive electrode) and receives an attractive force from the drive electrode B (negative electrode). The negative electret 5b receives a repulsive force from the drive electrode C (negative electrode) and receives an attractive force from the drive electrode D (positive electrode). For this reason, the movable element 2 receives a force in the right direction in FIG. 4A and moves to the right by one drive electrode pitch d.

  FIG. 4B shows the voltage state of the electret and the drive electrode immediately after switching at time t2.

  In this state, the electret 5a receives a repulsive force from the drive electrode B (positive electrode) and receives an attractive force from the drive electrode C (negative electrode). The electret 5b receives a repulsive force from the drive electrode D (negative electrode) and receives an attractive force from the drive electrode A (positive electrode). Therefore, the mover 2 receives a force in the right direction in FIG. 4B and moves by one drive electrode pitch d.

  Similarly, FIG. 4C shows the voltage state of the electret and the drive electrode immediately after switching at time t3.

  In this state, the electret 5a receives a repulsive force from the drive electrode C (positive electrode) and receives an attractive force from the drive electrode D (negative electrode). The electret 5b receives a repulsive force from the drive electrode A (negative electrode) and receives an attractive force from the drive electrode B (positive electrode). Therefore, the mover 2 receives a force in the right direction in FIG. 4C and moves by one drive electrode pitch d.

  Further, FIG. 4D shows the state of the electret and drive electrode voltages immediately after switching to time t4.

  In this state, the electret 5a receives a repulsive force from the drive electrode D (positive electrode) and receives an attractive force from the drive electrode A (negative electrode). The electret 5b receives a repulsive force from the drive electrode A (negative electrode) and receives an attractive force from the drive electrode C (positive electrode). For this reason, the moving element 2 receives a force in the right direction of FIG. 4D and moves by one drive electrode pitch d.

  As described above, the movable element 2 moves by one drive electrode pitch d, and this operation is repeated, so that the movable element 2 is changed as shown in FIGS. 4 (a) → (b) → (c) → (d). Move to the right (arrow F direction in the figure). In order to move the mover 2 in the left direction in the figure, the polarity of the voltage applied to the drive electrode 4 may be switched in reverse.

  Next, an embodiment of the present invention will be described.

(First embodiment)
5A and 5B show a configuration of an electret shutter unit applied to the digital single-lens reflex camera according to the first embodiment of the present invention. FIG. 5A is a front view and FIG. 5B is a cross-sectional view.

  The electret shutter unit (electrostatic shutter device) 21 is independently a focal plane having a front curtain (shutter front curtain) 25a and a rear curtain (shutter rear curtain) 25b that travel in the direction of the arrow F in the figure at the time of shooting. It is a shutter. The front curtain 25a and the rear curtain 25b are provided with the above-described electret 5 (not shown). And on the opposing surface side of each electret 5, a drive electrode which is a plurality of strip-like extended electrode members (not shown in FIG. 5, but a first drive electrode part and a second drive electrode part) And stators (fixing members) 29a and 29b provided with openings (or transmission parts) 27a and 27b.

  The front curtain 25a and the rear curtain 25b are configured to be movable in the longitudinal direction of the stators 29a and 29b, respectively. Although not shown in FIG. 5, the plurality of electrodes are arranged in parallel at predetermined intervals on the stators 29a and 29b in a direction perpendicular to the moving direction of the front curtain 25a and the rear curtain 25b. .

  Cover glasses 23 and 24 are provided on the subject side (left side in FIG. 5B) of the electret shutter unit 21 and the imager side (right side in FIG. 5B) to be described later, respectively. . These cover glasses 23 and 24 also serve as protection members for the electret shutter unit 21. Note that at least the front cover glass 23 is formed of a half mirror, and may be provided with an antireflection curtain.

  On the stators 29a and 29b, guides 35 to 38 are provided above and below the front curtain 25a and the rear curtain 25b, respectively, along the traveling direction of the front curtain 25a and the rear curtain 25b. These guides 35 to 38 are for assisting the traveling of the front curtain 25a and the rear curtain 25b. Further, on the stators 29a and 29b, light-shielding sealing members 33 and 34 are disposed in the vicinity of the end portions thereof.

  Here, the stators 29a and 29b are made of glass or the like as a substrate, a driving electrode (not shown) is formed on the surface, and an insulating film (not shown) is further provided on the driving electrode. ing. By applying this insulating film, a short circuit between adjacent drive electrodes is prevented.

  On the other hand, the front curtain 25a and the rear curtain 25b are made of polyimide or Teflon (registered trademark) as a base material, and are subjected to a light shielding process such as applying a light shielding material. Thereby, it can have a function as a light-shielding curtain. Therefore, irregular reflection of light in the electret shutter unit 21 can be prevented.

  A plurality of electrets are formed by a corona discharge method on one surface of the base material (film film) used as the front curtain 25a and the rear curtain 25b, in this case, on the surface facing the drive electrode ( This is called electretization). In the present embodiment, electret portions having positive and negative polarities are alternately arranged (see, for example, electrets 5a and 5b in FIG. 4).

  The openings 27 a and 27 b of the stators 29 a and 29 b described above are provided at positions corresponding to the openings 27 provided in the electret shutter unit 21. Thereby, the subject light taken in from the opening 27 is guided to an imager (described later) that is a photoelectric conversion element, and the image of the subject is photoelectrically converted by the imager.

  The electret shutter unit 21 does not use the charges induced in the front curtain 25a and the rear curtain 25b, but uses the charges that are permanently polarized in the electret, so the shutter rise time is shortened and the shutter operation is performed at high speed. Can be

  In addition, since the charge amount of the electret can be given arbitrarily, an optimum charge amount that maximizes the driving force can be given, and an extremely large driving force can be obtained. Therefore, the optimal electret shutter unit 21 according to the size of the imager described later can be configured.

  Furthermore, since the front curtain 25a and the rear curtain 25b can use a resin material as a raw material, they are lightweight. For example, the front curtain 25a and the rear curtain 25b can be formed of thin films of 10 to 20 μm. Therefore, the amount of electric power required for the operation is small, and a quiet operation can be realized, and the shock and sound accompanying the operation can be made extremely small.

  FIG. 6 is a diagram showing a schematic arrangement configuration of a digital single-lens reflex camera on which the electret shutter unit 21 is mounted.

  In FIG. 6, the digital single-lens reflex camera includes a body unit 50 and a lens unit 51 that can be exchanged as an accessory device, for example, on the front surface of the body unit 50.

  In the body unit 50, the above-described electret shutter unit 21 is disposed on the optical axis of a lens group (not shown) in the lens unit 51. A main mirror 70 composed of a half mirror that is a semi-translucent member is provided on the front surface of the electret shutter unit 21. The incident light beam reflected by the main mirror 70 reaches the loupe lens 73 via the focusing screen 71 and the pentaprism 72.

  An optical low-pass filter 40 and an imager 42, which is a photoelectric conversion element, are disposed behind the electret shutter unit 21 (on the right side in FIG. 6). Reference numeral 43 denotes a seal member for sealing between the imager 42 and the optical low-pass filter 40.

  In addition, although the electret shutter unit 21 is shown in FIG. 6 so as to be inclined at about 45 °, the present invention is not limited to this.

  Assume that a light beam from a subject (not shown) is incident through the lens unit 51. When observing the subject, the light beam incident through the lens unit 51 is reflected by the main mirror 70 of the electret shutter unit 21 and is focused on the focusing screen 71. Further, an erect image is observed by the photographer through the magnifying lens 73 via the pentaprism 72.

  When the subject is observed, the openings 27, 27a and 27b of the electret shutter unit 21 are fully closed. That is, the openings 27 and 27a are covered by the front curtain 25a, and the subject luminous flux is shielded from the imager 42.

  During the imaging operation, the front curtain 25a is driven in the direction of arrow F shown in FIG. 5A, and the openings 27, 27a, and 27b are fully opened. Thereby, the subject light flux is guided to the imager 42.

  Thereafter, when a predetermined time has elapsed, the rear curtain 25b is driven in the direction of arrow F shown in FIG. 5B, and the openings 27, 27a and 27b are shielded. Thereby, the openings 27, 27a and 27b are covered and completely shielded from light. Therefore, the subject light flux reflected again by the main mirror 70 is in a state where it can be observed by the photographer through the loupe lens 73.

  Thereafter, the front curtain 25a and the rear curtain 25b return to the initial state shown in FIG. 5A and wait for the next imaging operation.

  FIG. 7 is a block diagram showing an electrical system configuration of the digital single-lens reflex camera using the electret shutter unit according to the first embodiment of the present invention.

  In FIG. 7, this camera system records image data photographed via a body unit 50, an accessory device such as a replaceable lens unit (that is, a lens barrel) 51, and a communication connector 56. A recording medium 52 and an external flash unit 53 are provided via a flash communication connector 57.

  The lens unit 51 can be detachably mounted via a lens mount (not shown) provided on the front surface of the body unit 50. The lens unit 51 includes photographing lenses 61a and 61b, a diaphragm 62, a lens driving mechanism 63, a diaphragm driving mechanism 64, and a lens control microcomputer (hereinafter abbreviated as Lμcom) 65. Yes.

  The photographing lenses 61a and 61b are driven in the optical axis direction by a DC motor (not shown) existing in the lens driving mechanism 63. The diaphragm 62 is driven by a stepping motor (not shown) existing in the diaphragm drive mechanism 64. The Lμcom 65 drives and controls each part in the lens unit 51 such as the lens driving mechanism 63 and the aperture driving mechanism 64. The Lμcom 65 is electrically connected to a body control microcomputer 85, which will be described later, via the communication connector 55, and is controlled in accordance with a command from the body control microcomputer 85.

  On the other hand, the body unit 50 is configured as follows.

  A light beam from a subject (not shown) that enters through the photographing lenses 61 a and 61 b and the diaphragm 62 in the lens unit 51 is reflected by the main mirror 70 of the electret shutter unit 21, and passes through a focusing screen 71 and a pentaprism 72. The loupe lens 73 is reached.

  As described above, the electret shutter unit 21 transmits part of the light flux through the opening 27 and the like exposed when the shutter front curtain 25a and the rear curtain 25b travel. The transmitted light beam is guided to the imager 42 via the optical low-pass filter 40.

  The body unit 50 also includes an image sensor interface circuit 80 connected to the imager 42, an SDRAM 82 provided as a storage area, and a recording medium 52 via the liquid crystal monitor 83 and the communication connector 56. Is connected to an image processing controller 81. These are configured to provide an electronic recording display function together with an electronic imaging function.

  The recording medium 52 is an external recording medium such as various memory cards or an external hard disk drive (HDD), and is attached to the camera body 50 via the communication connector 56 so as to be exchangeable.

  The image processing controller 81 includes a communication connector 55, a photometry circuit 86, an AF sensor drive circuit 88, a shutter drive control circuit 90 as drive means, a non-volatile memory (EEPROM) 91, and the like in the body unit 50. Are connected to a body control microcomputer 85 (hereinafter abbreviated as “Bμcom”) for controlling the respective components.

  The Bμcom 85 is connected with an operation display LCD 92 for notifying the photographer of the operation state of the camera by display output, a camera operation switch (SW) 93, and a battery 96 via a power supply circuit 95. .

  The Bμcom 85 and Lμcom 65 are electrically connected via the communication connector 55 when the lens unit 51 is mounted. As a digital camera, the Lμcom 65 is operated in cooperation with the Bμcom 85 in a dependent manner.

  The photometric circuit 86 is a circuit that performs photometric processing based on the light flux taken into the imager 42. The AF sensor driving circuit 88 is a circuit for driving and controlling the imager 42 as an AF sensor for performing automatic ranging. The shutter drive control circuit 90 controls the movement of the front curtain 25a and the rear curtain 25b of the electret shutter unit 21 and also exchanges a signal for controlling the opening / closing operation of the shutter with the Bμcom 85 and a signal synchronized with the strobe. I do.

  The non-volatile memory 91 is a storage unit that stores predetermined control parameters necessary for camera control as other storage areas, and is provided so as to be accessible from the Bμcom 85.

  The operation display LCD 92 is for notifying the photographer of the operation state of the camera by display output. The camera operation switch 93 is a group of switches including operation buttons necessary for operating the camera, such as a release switch for instructing execution of a shooting operation, a mode change switch for switching between a shooting mode and an image display mode, and a power switch. Composed.

Further, the power circuit 95 is provided for converting the voltage V _E of the battery 96 as a power source into a voltage V _C required by each circuit unit of the camera system.

  The strobe unit 53 includes a flash light emitting unit 101, a DC / DC converter 102, a strobe control microcomputer 103, and a battery 104. The strobe unit 53 can be mounted so as to be communicable with the body unit 50 via a strobe communication connector 57.

  Each part of the digital camera configured as described above operates as follows.

  First, the image processing controller 81 controls the image sensor interface circuit 80 in accordance with a command of Bμcom 85, and image data is captured from the image capture module 20. This image data is taken into the SDRAM 82 which is a temporary storage memory. The SDRAM 82 is used as a work area when image data is converted. The image data is set to be stored in the recording medium 52 after being converted into JPEG data.

  The distance measurement output from the imager 42 is transmitted to the Bμcom 85 via the AF sensor driving circuit 88 and a known distance measurement process is performed. On the other hand, from the eyepiece lens 73 adjacent to the pentaprism 72, the photographer can see the subject. Further, the light beam taken in by the imager 42 is guided to a photosensor (not shown) in the photometry circuit 86, and a well-known photometry process is performed based on the amount of light detected here.

  When the shutter drive control circuit 90 receives a signal for controlling the drive of the shutter from the Bμcom 85, the shutter unit 21 is controlled based on the signal. At the same time, the shutter drive control circuit 90 outputs a strobe tuning signal for causing the Bμcom 85 to emit a strobe at a predetermined timing. Based on this strobe tuning signal, the Bμcom 85 outputs a light emission command signal to the strobe unit 53 by communication.

  Further, when the mode change switch in the camera operation switch 93 described above is operated by the photographer to switch from the shooting mode to the image display mode, the image data stored in the recording medium 52 is read out, and the liquid crystal monitor 83 can be displayed. The image data read from the recording medium 52 is converted into a video signal by the image processing controller 81 and output and displayed on the liquid crystal monitor 83.

  When the operation of the power supply circuit 95 is stopped by turning off the power supply switch 98, the operation of the power supply circuit is not started unless the power supply switch 98 is turned on again.

  The shutter device of the present embodiment is configured by the electret shutter unit 21 and the shutter drive control circuit 90 shown in FIG.

  FIG. 8 is a configuration diagram showing signal connection between the shutter drive control circuit 90 and the electret shutter unit 21.

  As described above, the electret shutter unit 21 includes the front curtain 25a and the rear curtain 25b. In order to drive the respective curtains, the phase shifter 112a having the same configuration as that shown in FIG. , 112b are provided as two drive circuits 113a, 113b as drive means. The pulse generation circuit 111 drives the drive electrodes 28a and 28b based on the open / close control signal from the Bμcom 85. As a result, the permanently polarized derivatives (electrets) 26a and 26b provided in the front curtain 25a and the rear curtain 25b are sequentially sucked by the A to D of the drive electrodes 28a and 28b, and the front curtain 25a and the rear curtain 25b are driven. Is done. Thus, the fully open / close operation of the opening 27 shown in FIG. 5A is controlled.

  When a reset signal is received from Bμcom 85, the leading curtain 25a and trailing curtain 25b are driven to the initial state. Further, the strobe tuning signal is output from the pulse generation circuit 111 to the Bμcom 85 at a predetermined timing.

  In the above-described embodiment, the electret shutter unit 21 covers the opening 27 with the shutter curtains (the front curtain 25a and the rear curtain 25b) when observing the subject, reflects the light flux from the subject with the main mirror 70, and is a pentaprism. 72 and the loupe lens 73 are used to observe the subject.

  However, the present invention is not limited to this. For example, the subject 27 is captured in the imager 42 with the opening 27 fully opened, and the subject image is sequentially displayed on the liquid crystal monitor 83 via the image sensor interface circuit 80 and the image processing controller 81. You may be made to do. In this case, at the time of the imaging operation, for example, the opening 27 is once closed by the front curtain 25a (or the rear curtain 25b), and after the charge accumulated in the imager 42 is discharged, the normal imaging operation is started. That's fine.

  As described above, according to the first embodiment, by using the electret shutter unit 21, it is possible to reduce the operating noise of the shutter at the time of release. Furthermore, by adopting an electret shutter unit instead of the quick return mirror, the operation sound of the mirror and the shock generated by the operation are eliminated.

(Second Embodiment)
In the first embodiment described above, the electret shutter unit 21 is disposed at an angle of approximately 45 °. However, in consideration of the exposure time for the imager 42, the electret shutter unit 21 is disposed substantially parallel to the imaging surface of the imager 42. Preferably it is done. The second embodiment is an example in which the electret shutter unit 21 is disposed substantially parallel to the imaging surface of the imager 42.

  In addition, since the opening area of the electret shutter is smaller than the case where it is installed at 45 ° as in the first embodiment, the drive voltage is reduced in addition to the downsizing of the entire electret. Advantages such as reduced material costs and improved camera space efficiency are produced.

  FIG. 9 shows a second embodiment of the present invention, and is a diagram showing a schematic arrangement configuration of a digital single-lens reflex camera on which an electret shutter unit 21 is mounted.

  Note that the second embodiment differs from the first embodiment described above only in the configuration using a beam splitter that branches the light beam from the subject, and the configuration and basics of the camera on which the electret shutter unit is mounted. Since the basic operation and the like are basically the same as those shown in FIGS. 6 to 8, the same reference numerals are given to the same portions, and illustration and description thereof are omitted.

  In FIG. 9, a beam splitter 45 that branches a light beam from a subject is disposed on the optical axis of a lens group (not shown) in the lens unit 51 in the body unit 50 of the digital single-lens reflex camera. The beam splitter 45 is configured by bonding two 45 ° triangular prisms, and a half mirror layer 45a, which is a semi-transparent member, is coated on the boundary surface of the beam splitter 45 so that a half mirror surface 45a is formed. Is provided.

  The beam splitter 45 is provided on the front surface of the imager 42 instead of the main mirror 70 (cover glass 23) in the first embodiment described above. An optical low-pass filter 40 and an imager 42 are arranged behind the electret shutter unit 21 (on the right side in FIG. 9) so that the light beam that has passed through the half mirror surface 45a of the beam splitter 45 is guided to the imager 42. ing. In this case, the shutter curtain in the electret shutter unit 21 and the imaging surface of the imager 42 are arranged substantially in parallel.

  On the other hand, the light beam from the subject reflected by the half mirror surface 45 a of the beam splitter 45 reaches the loupe lens 73 via the focusing screen 71 and the pentaprism 72.

  By configuring in this way, as in the first embodiment described above, it is possible to reduce the operating noise of the shutter at the time of release, and to prevent a shock generated by the operation. In addition, since the shutter curtain is arranged substantially parallel to the imaging surface of the imager 42, the distance from the shutter position to the imaging surface becomes equal, and there is no possibility of blurring the image.

  As mentioned above, although embodiment of this invention was described, in the range which does not deviate from the summary of this invention other than embodiment mentioned above, this invention can be variously modified.

It is a figure explaining the drive principle of the electrostatic shutter apparatus which concerns on this invention. It is the figure which showed the drive circuit of this electret shutter while showing the cross section of an electret shutter typically. 2 shows an example of a voltage signal train created by the drive circuit 10 of FIG. 2 and applied to the drive electrodes 4A to 4D, where (a) shows the drive electrode 4A, (b) shows the drive electrode 4B, and (c). Is a drive electrode 4C, and (d) is a timing chart of the drive electrode 4D. It is a figure explaining operation | movement of the electret shutter 7 shown by FIG. The structure of the electret shutter unit applied to the digital single-lens reflex camera of 1st Embodiment which concerns on this invention is shown, (a) is a front view, (b) is sectional drawing. It is the figure which showed schematic arrangement configuration of the digital single-lens reflex camera with which the electret shutter unit 21 of FIG. 5 was mounted. It is a block diagram which shows the system configuration | structure of the electric system of the digital single-lens reflex camera using the electret shutter unit which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the signal connection of the shutter drive control circuit 90 and the electret shutter unit 21 of FIG. FIG. 9 is a diagram illustrating a schematic arrangement configuration of a digital single-lens reflex camera on which an electret shutter unit 21 is mounted according to a second embodiment of the present invention.

Explanation of symbols

  1, 29a, 29b ... Stator, 2 ... Mover, 3, 27, 27a, 27b ... Opening, 4, 4A-4D, 28a, 28b ... Drive electrode, 5, 5a, 5b, 26a, 26b ... Permanent polarization 7 ... electret shutter, 10 ... drive circuit, 12 ... pulse generation circuit, 13 ... phase shifter, 14 ... booster circuit, 20 ... imaging module, 21 ... electret shutter unit, 23, 24 ... cover glass 25a ... front curtain, 25b ... rear curtain, 27, 27a, 27b ... opening, 33, 34 ... sealing member, 35-38 ... guide, 40 ... optical low-pass filter, 50 ... body unit, 51 ... lens unit, 52 ... Recording medium, 53 ... Strobe unit, 61a, 61b ... Shooting lens, 62 ... Aperture, 65 ... Microcomputer for lens control ( .mu.com), 70 ... main mirror, 80 ... imaging element interface circuit, 81 ... image processing controller, 85 ... body control microcomputer (B.mu.com), 90 ... shutter drive control circuit, 93 ... camera operation switch (SW), 95 ... Power supply circuit 101... Flash light emitting unit 103. Strobe control microcomputer.

Claims (23)

In a digital single lens reflex camera having an electrostatic shutter device for driving a shutter curtain using an electrostatic force,
A member having a semi-transmission characteristic is disposed on the subject light incident side of the electrostatic shutter device, and the light reflected by the member is guided to the finder optical system of the subject image, and the transmitted light is guided to the image sensor. A digital single-lens reflex camera characterized by that.   The digital single-lens reflex camera according to claim 1, wherein the member is disposed in parallel with the electrostatic shutter device.   The digital single-lens reflex camera according to claim 1, wherein a shutter curtain of the electrostatic shutter device travels in parallel with the member.   The digital single-lens reflex camera according to claim 1, wherein the member is a beam splitter prism.   2. The digital single-lens reflex camera according to claim 1, wherein an anti-reflection curtain is formed on a surface of the electrostatic shutter device on which subject light is incident. In a digital single lens reflex camera having an electrostatic shutter device for driving a shutter curtain using an electrostatic force,
A digital camera comprising a beam splitter prism that separates a subject light beam into a finder optical system side and an image sensor side, and the electrostatic shutter is integrally disposed on an exit surface of the beam splitter prism on the image sensor side. Single-lens reflex camera.   The electrostatic shutter device receives an electrostatic force generated when a voltage is applied to the driving electrode and an electrode member having a plurality of driving electrodes provided on the surface, and moves relative to the electrode member. 7. The digital single-lens reflex camera according to claim 6, wherein the moving member is sandwiched between the imaging element side emission surface of the beam splitter prism and the electrode member. .   7. The digital single-lens reflex camera according to claim 6, wherein a shutter curtain of the electrostatic shutter device travels in parallel with an exit surface of the beam splitter prism.   7. The digital single-lens reflex camera according to claim 6, wherein an anti-reflection curtain is formed on a surface of the electrostatic shutter device on which subject light is incident. A viewfinder optical system for observing the subject image via the taking lens;
An image sensor that converts a subject luminous flux incident through the photographing lens into an electrical signal;
An electrostatic shutter device disposed on an optical path between the photographing lens and the image sensor and driving a shutter curtain using an electrostatic force;
In a digital single-lens reflex camera equipped with
The electrostatic shutter device includes a semi-transmissive member disposed on the side on which subject light is incident, and the subject light beam incident through the photographing lens and reflected by the semi-transmissive member is transmitted to the finder optical system. A digital single-lens reflex camera, wherein the subject luminous flux transmitted through the translucent member is guided to the image sensor.   The digital single-lens reflex camera according to claim 10, wherein the semi-transmissive member is disposed in parallel with a shutter curtain of the electrostatic shutter device.   The digital single-lens reflex camera according to claim 10, wherein a shutter curtain of the electrostatic shutter device travels in parallel with the semi-transmissive member.   The digital single-lens reflex camera according to claim 10, wherein the translucent member is a beam splitter prism.   The digital single-lens reflex camera according to claim 10, wherein an anti-reflection curtain is formed on a surface on which subject light is incident on the electrostatic shutter device. A viewfinder optical system for observing the subject image via the taking lens;
An image sensor that converts a subject luminous flux incident through the photographing lens into an electrical signal;
An electrostatic shutter device disposed on an optical path between the photographing lens and the image sensor and driving a shutter curtain using an electrostatic force;
In a digital single-lens reflex camera equipped with
The object light beam is separated into the finder optical system side and the imaging element side, and further includes a beam splitter prism in which the electrostatic shutter device is integrally disposed on the exit surface of the imaging element side. A digital SLR camera.   The electrostatic shutter device receives an electrostatic force generated when a voltage is applied to the driving electrode and an electrode member having a plurality of driving electrodes provided on the surface, and moves relative to the electrode member. 16. The digital single-lens reflex camera according to claim 15, wherein the movable member is sandwiched between the imaging element side exit surface of the beam splitter prism and the electrode member. .   16. The digital single-lens reflex camera according to claim 15, wherein the shutter curtain of the electrostatic shutter device travels in parallel with the exit surface of the beam splitter prism.   16. The digital single-lens reflex camera according to claim 15, wherein an anti-reflection curtain is formed on a surface of the electrostatic shutter device on which a subject luminous flux is incident. A viewfinder optical system for observing the subject image via the taking lens;
An image sensor that converts a subject luminous flux incident through the photographing lens into an electrical signal;
An electrostatic shutter device disposed on an optical path between the photographing lens and the image sensor and driving a shutter curtain using an electrostatic force;
In a digital single-lens reflex camera equipped with
The electrostatic shutter device has a semi-transmissive member disposed on the side on which subject light is incident, and is incident through the photographing lens when the shutter curtain is in a position to block the optical path of the subject luminous flux. The reflected subject light beam is reflected and guided to the finder optical system, and when the shutter curtain is at a position where the optical path of the subject light beam is opened, the subject light beam transmitted through the semi-transmissive member is guided to the image sensor. Digital SLR camera featuring   The digital single-lens reflex camera according to claim 19, wherein the semi-transmissive member is disposed in parallel with a shutter curtain of the electrostatic shutter device.   The digital single-lens reflex camera according to claim 19, wherein a shutter curtain of the electrostatic shutter device runs in parallel with the semi-transmissive member.   The digital single-lens reflex camera according to claim 19, wherein the translucent member is a beam splitter prism.   20. The digital single-lens reflex camera according to claim 19, wherein an anti-reflection curtain is formed on a surface of the electrostatic shutter device on which subject light is incident.

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