JP2008004994A - Digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a user-friendly digital camera having a half mirror arranged in a photography optical path by preventing damage on the half mirror. <P>SOLUTION: The digital camera comprises a half mirror 201 advancing/retracting in the optical path of a taking lens and reflecting a part of the object light beam in the optical path, a ranging sensor unit 451 including a ranging sensor 457 for detecting the focal point state of the taking lens by the object light beam reflected on the movable mirror, and a resilient member 421 at a position abutting against the movable half mirror 201 when it retracts from the optical path wherein the resilient member 421 is arranged around the opening 459a of the ranging sensor unit 451. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a digital camera having a through image display function, and more specifically, a so-called through image display function (also referred to as a live view display function or an electronic viewfinder function) for displaying an image acquired by an image sensor as a moving image on a display device. The present invention relates to a digital camera.

In conventional digital cameras, the subject image was observed using an optical viewfinder, but recently, the optical viewfinder has been eliminated, and instead the output of an image sensor provided for recording subject image data is displayed. Also use it. That is, there are an increasing number of images having a through image display function for displaying an image acquired by an image sensor on a display device such as a liquid crystal monitor for observing a subject image.

As a digital camera having such a through image display function, for example, Japanese Patent Application Laid-Open No. H10-228707 obtains a subject image to an imaging device by retracting a movable mirror from a photographing optical path and fully opening a focal plane shutter. An interchangeable lens camera that continuously displays a subject image on a liquid crystal monitor is disclosed. However, in Patent Document 1, a TTL (Trough The Lens) phase difference AF (Auto Focus) generally adopted in a conventional camera is used in order to retract the movable mirror out of the photographing optical path during live view display. There is a problem that can not be done.
JP 2002-369042 A

Therefore, Patent Document 2 proposes a digital camera in which a movable mirror is configured by a half mirror, and a subject light beam that has passed through a photographing optical system is guided to both an image sensor and a phase difference AF sensor. According to this configuration, phase difference AF is also possible while displaying a through image, and the above-described problem can be solved.
Japanese Patent Laid-Open No. 2002-6208

However, when a configuration in which a half mirror is arranged in a photographing optical path as in Patent Document 2 is applied to a digital camera, the following problem may occur. That is, since the half mirror is very thin, there is a possibility that it will be broken if the user touches it with a finger. In addition, there is a risk of breaking due to shock or vibration during operation. Further, since the distance measuring sensor arranged in the vicinity of the half mirror and in the mirror box is usually exposed, there is a problem that dust such as dust tends to adhere.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a digital camera that prevents damage to the half mirror and is easy to use in a digital camera in which the half mirror is disposed in the photographing optical path.

In order to achieve the above object, the digital camera according to the first aspect of the present invention is capable of moving back and forth in the optical path of the taking lens, and in the optical path, a movable mirror that reflects a subject light beam, and a subject reflected by the movable mirror. A distance measuring sensor unit including a distance measuring sensor that detects a focus state of the photographing lens by a light beam, and a buffer member that contacts when the movable mirror is retracted from the optical path, the buffer member being the distance sensor unit It is arrange | positioned around the opening part.

According to a second aspect of the present invention, in the digital camera according to the first aspect, the movable mirror seals the opening of the distance measuring sensor unit when contacting the buffer member.
According to a third aspect of the present invention, there is provided a digital camera according to the first aspect, wherein the photographing lens is replaceable, and the movable mirror is in a position in contact with the buffer member in response to removal of the photographing lens. Moving.
Furthermore, in the digital camera according to the fourth invention, in the first invention, the movable mirror includes a mirror member and a holding member for holding the mirror member, and the holding member abuts on the buffer member.

In order to achieve the above object, a digital camera according to a fifth aspect of the present invention is disposed in a mirror box in the camera body and can be moved back and forth in the optical path of the taking lens. A movable half mirror that reflects and transmits another light beam, and a buffer member that is disposed in the mirror box at a position in contact with the movable mirror.

A digital camera according to a sixth invention is the digital camera according to the fifth invention, wherein the buffer member is disposed at the bottom of the mirror box and abuts the movable mirror when the movable half mirror is in the retracted state.
According to a seventh aspect of the present invention, in the digital camera according to the fifth aspect, the buffer member has a shape along the shape of the peripheral edge of the movable half mirror.
Furthermore, a digital camera according to an eighth aspect of the present invention is the above-described fifth aspect, further comprising a distance measuring sensor unit including a distance measuring sensor that detects a focus state of the photographing lens by a subject light beam reflected by the movable mirror. When the movable half mirror is in the retracted state, the opening of the distance measuring sensor unit is covered.

According to the present invention, since the buffer member is arranged around the opening of the distance measuring sensor unit, the half mirror can be prevented from being damaged and an easy-to-use digital camera can be provided.

Hereinafter, a preferred embodiment using a digital camera to which the present invention is applied will be described with reference to the drawings. FIG. 1 is a block diagram mainly showing an electric system of a digital camera according to an embodiment of the present invention. The lens barrel 10 is detachable from a mount opening (not shown) on the front surface of the camera body 20. The subject luminous flux from the photographing lens including the lenses 101a and 101b in the lens barrel 10 is guided into the camera body 20 through the mount opening. In the present embodiment, the lens barrel 10 and the camera body 20 are configured separately and are electrically connected via the communication contact 300. The attachment / detachment detection switch 259 provided on the camera body 20 can detect the attachment / detachment state.

Inside the lens barrel 10, there are disposed lenses 101a and 101b for focus adjustment and focal length adjustment, and a diaphragm 103 for adjusting the aperture. The lens 101 a and the lens 101 b are driven by an optical system driving mechanism 107, and the diaphragm 103 is connected to be driven by a diaphragm driving mechanism 109. The optical system driving mechanism 107 and the aperture driving mechanism 109 are each connected to a lens CPU 111, and the lens CPU 111 is connected to the camera body 20 via a communication contact 300. The lens CPU 111 controls the lens barrel 10 and controls the optical system driving mechanism 107 to perform focusing and zoom driving, and also controls the aperture driving mechanism 109 to control the aperture value.

In a mirror box in the camera body 20, a movable reflecting mirror 201 (referred to as a movable half mirror for convenience) having a characteristic of transmitting a part of the light beam that has passed through the lenses 101a and 101b is disposed. The movable half mirror 201 is driven by a movable mirror drive mechanism 215 and can rotate along an axis in a direction perpendicular to the paper surface around a rotation shaft 201a. When the movable half mirror 201 is at a position inclined by 45 degrees with respect to the optical paths of the lenses 101a and 101b (the position indicated by the solid line in FIG. 1), a part (for example, 30%) of the subject luminous flux is reflected, and the camera body 20 Is guided to a distance measuring / photometric sensor 217 provided at the bottom. Further, the remainder (70%) of the subject luminous flux passes through the movable half mirror 201 and is guided in the direction of a CCD (Charge Coupled Devices) 221. When the movable half mirror 201 is substantially parallel to the optical paths of the lenses 101a and 101b and is at a retracted position (a position indicated by a two-dot chain line in FIG. 1) that does not block the subject light beam, all of the subject light beam is guided to the CCD 221. The structure of the movable half mirror 201 will be described later with reference to FIG. In the present embodiment, the center of rotation of the movable half mirror 201 is the lower side in the mirror box, but is not limited to this, and may be the upper side or parallel to the paper surface on either the left or right side. Of course, the center of rotation may be used. In the present embodiment, the reflectance and transmittance of the half mirror are 30% and 70%, respectively, but are not limited to this ratio and can be changed as appropriate.

A distance measuring / photometric sensor 217 is arranged at the bottom of the mirror box in the camera body 20 at a position where the light beam reflected by the movable half mirror 201 is guided. The distance measuring / photometric sensor 217 includes a distance measuring sensor and a photometric sensor. The photometric sensor includes a multi-division photometric element that divides a subject image and performs photometry. The distance measuring sensor is a sensor for measuring a distance by the TTL phase difference method. The arrangement structure of the distance measuring sensor unit 451 including the distance measuring sensor will be described later together with the structure of the movable half mirror 201 with reference to FIG. The output of the distance measurement / photometry sensor 217 is sent to the distance measurement / photometry processing circuit 219. The distance measurement / photometry processing circuit 219 outputs an evaluation photometric value based on the output of the photometry sensor, and measures the focus shift amount of the subject image formed by the lenses 101 and 101b based on the output of the distance measurement sensor. To do. Note that the distance measuring sensor and the photometric sensor may be configured separately or integrally.

A focal plane type shutter 203 for controlling the exposure time and shielding the CCD 221 is disposed behind the movable half mirror 201 and on the optical axis of the lenses 101a and 101b and on the photographing optical path. The shutter 203 is driven and controlled by a shutter drive mechanism 213. A dustproof filter 205 is disposed behind the shutter 203. This is because dust generated in the mount opening of the camera body 20 and inside the body adheres to the CCD 221 and the optical element, and the shadow of the dust is reflected in the subject image. It is a filter to prevent it from becoming unsightly. A piezoelectric element 207 is fixed to the entire periphery or a part of the periphery of the dustproof filter 205, and this piezoelectric element 207 is connected to the dustproof filter drive circuit 211 and driven by this circuit. The piezoelectric element 207 is driven by the dust filter driving circuit 211 so that the dust filter 205 vibrates with a predetermined ultrasonic wave, and the dust attached to the front surface of the dust filter 205 is removed using the vibration. In addition, as long as dust attached to the image pickup device itself such as a CCD or an optical element disposed on the front side of the image pickup device can be removed, it is not limited to one using ultrasonic vibration as in the present embodiment. Of course, it may be appropriately replaced with various methods such as a method of blowing off by an air flow using an air pump or a method of collecting and removing dust using static electricity.

An infrared cut filter 209 for cutting an infrared light component from the subject light beam is disposed behind the dust-proof filter 205, and an optical low-pass filter 210 for removing a high frequency component from the subject light beam is disposed behind the dust filter 205. Has been. A CCD 221 serving as an image sensor is disposed behind the optical low-pass filter 210, and subjects images formed by the lenses 101a and 101b are photoelectrically converted into electric signals. The dustproof filter 205, the infrared cut filter 209, the optical low-pass filter 210, and the CCD 211 are integrally stored in a sealed package (not shown), and are configured so that dust does not enter the package. In the present embodiment, a CCD is used as an image sensor. However, the present invention is not limited to this, and a CMOS (Complementary Metal Oxide) is used.
Needless to say, a two-dimensional imaging device such as Semiconductor) can be used.

The CCD 221 is connected to the image sensor driving circuit 223 and is driven and controlled by a control signal from the input / output circuit 239. A photoelectric analog signal output from the CCD 221 is amplified and analog-digital converted (AD converted) by the image sensor driving circuit 223. The image sensor driving circuit 223 is connected to an image processing circuit 227 in an ASIC (Application Specific Integrated Circuit) 262, and the image processing circuit 227 performs digital amplification (digital gain adjustment processing) and color of digital image data. Various types of image processing such as correction, gamma (γ) correction, contrast correction, black and white / color mode processing, and through image processing are performed. The image processing circuit 227 is connected to the data bus 261. In addition to the image processing circuit 227, the data bus 261 includes a sequence controller (hereinafter referred to as "body CPU") 229, a compression / decompression circuit 231, a video signal output circuit 233, an SDRAM control circuit 237, and an input / output circuit 239. A communication circuit 241, a recording medium control circuit 243, a flash memory control circuit 247, and a switch detection circuit 253 are connected.

The body CPU 229 connected to the data bus 261 controls the operation of this digital camera. A compression / decompression circuit 231 connected to the data bus 261 is a circuit for compressing image data stored in the SDRAM 238 by JPEG or TIFF. Note that image compression is not limited to JPEG or TIFF, and other compression methods can be applied. The video signal output circuit 233 connected to the data bus 261 is connected to the rear liquid crystal monitor 26 and the finder liquid crystal monitor 29 (abbreviated as “F liquid crystal monitor” in the figure) via the liquid crystal monitor drive circuit 235. The video signal output circuit 233 is a circuit for converting the image data stored in the SDRAM 238 or the recording medium 245 into a video signal for display on the rear liquid crystal monitor 26 and / or the in-viewfinder liquid crystal monitor 29. The rear liquid crystal monitor 26 is disposed on the rear surface of the camera body 20. However, the rear liquid crystal monitor 26 is not limited to the rear surface and may be other display devices as long as the photographer can observe. The in-viewfinder liquid crystal monitor 29 is disposed at a position that can be observed by the photographer through the viewfinder eyepiece, and, like the rear liquid crystal monitor 26, is not limited to the liquid crystal and may be another display device. Note that only the rear liquid crystal monitor 26 may be used for observation of the subject image, and the finder eyepiece and the finder liquid crystal monitor 29 may be omitted.

The SDRAM 238 is connected to the data bus 261 via the SDRAM control circuit 237, and the SDRAM 238 temporarily stores the image data processed by the image processing circuit 227 or the image data compressed by the compression / expansion circuit 231. This is a buffer memory. The input / output circuit 239 connected to the above-described dustproof filter drive circuit 211, shutter drive mechanism 213, movable mirror drive mechanism 215, distance measurement / photometry processing circuit 219, and image sensor drive circuit 223 is connected to the body CPU 229 via the data bus 261. Control input / output of data with each circuit. The communication circuit 241 connected to the lens CPU 111 via the communication contact 300 is connected to the data bus 261, and exchanges data with the body CPU 229 and the like and communicates control commands.

A recording medium control circuit 243 connected to the data bus 261 is connected to the recording medium 245 and controls recording of image data and the like on the recording medium 245. The recording medium 245 can be loaded with any rewritable recording medium such as an xD picture card (registered trademark), a compact flash (registered trademark), an SD memory card (registered trademark), or a memory stick (registered trademark). And is detachable from the camera body 20. In addition, a hard disk unit such as a microdrive (registered trademark) or a wireless communication unit may be connectable.

A flash memory control circuit 247 connected to the data bus 261 is connected to a flash memory 249. The flash memory 249 stores a program for controlling the flow of the camera. The digital camera is controlled according to the program stored in the flash memory 249. Note that the flash memory 249 is an electrically rewritable nonvolatile memory.

Power switch 257 that is turned on / off in conjunction with a power switch lever for controlling power supply of the camera body 20 and the lens barrel 10, a switch that is linked to a shutter release button, and a playback button that designates a playback mode. , A switch linked to the cross button for instructing the movement of the cursor on the screen of the rear LCD monitor 26, a switch linked to the mode dial for instructing the shooting mode, and an OK linked to the OK button for determining each selected mode. Various switches 255 such as a switch and an attachment / detachment detection switch 259 are connected to the data bus 261 via a switch detection circuit 253. The release button has a first release switch that is turned on when the photographer is half-pressed and a second release switch that is turned on when the photographer is fully pressed. When the first release switch (hereinafter referred to as 1R) is turned on, the camera performs photographing preparation operations such as focus detection, focusing of the photographing lens, and photometry of the subject brightness, and the second release switch (hereinafter referred to as 2R). When the switch is turned on, a shooting operation for capturing image data of a subject image is executed based on the output of the CCD 221 serving as an image sensor.

Next, the driving means / retracting means of the movable half mirror 201 and the distance measuring sensor unit 451 will be described with reference to FIG. 2A is an external perspective view of the movable half mirror 201 in the reflecting state, and FIG. 2B is an XX sectional view of the movable half mirror 201 in the retracted state. A half mirror 401 that transmits part of the subject luminous flux and reflects part of it is held by a mirror frame 403. The coating film is attached to a very thin plate glass having a thickness of 0.4 mm or less, and the half mirror 401 transmits a part of the light flux and reflects the other light flux as described above. The mirror frame 403 is rotatable around a shaft 411 inserted in the hole 403a, and the rotation shaft 201a in FIG. Both ends of an opening spring 407 are engaged between a pin 409 fixed to the camera body 20 and a driving pin 405 implanted in the mirror frame 403, and a coil portion of the opening spring 407 is wound around a shaft 411. It is disguised. Due to the spring force of the opening spring 407, the mirror frame 403 receives a biasing force in the counterclockwise direction (arrow A direction) in the figure. One end of the drive pin 405 and the locking lever 413 are engaged, and the cam pin 415 implanted at the other end of the locking lever 413 is engaged with the mirror cam 417.

The locking lever 413 is pivotally supported by a mirror box (not shown), and receives a biasing force counterclockwise (arrow B direction) in the figure by the spring force of the opening spring 407 via the drive pin 405. Yes. Therefore, the cam pin 415 of the locking lever 413 is in pressure contact with the cam surface of the mirror cam 417. The cam surface of the mirror cam 417 is formed so that the length in the radial direction from the center of rotation changes. That is, the locking position 417a on the cam surface is formed so that the distance from the rotation center is longer, and the locking release position 417b is formed so that the distance from the rotation center is shorter than the locking position 417a. ing. A cam surface is formed with a step 417c from the locking position 417a to the locking release position 417b in the counterclockwise direction in the drawing, and the cam surface is smoothly displaced from the locking release position 417b to the locking position 417a. It is formed.

When the locking position 417a of the mirror cam 417 is in a position where it abuts on the cam pin 415, the locking lever 413 is restricted from rotating in the direction of arrow B by the mirror cam 417. Hold on. From this state, when the mirror cam 417 is rotated clockwise in the drawing to a position where the unlocking position 417b contacts the cam pin 415 through the step 417c, the locking lever 413 is rotated in the arrow B direction. It becomes possible. Therefore, the mirror frame 403 is rotated in the direction of arrow A by the urging force of the opening spring 407 and displaced to the retracted position. The mirror cam 417 is rotationally driven by a motor (not shown).

The driving means for driving the movable half mirror 201 to the reflection position (the position indicated by the solid line in FIG. 1) in the imaging optical path includes a mirror cam 417, a locking lever 413, and the like. The retracting means for driving the movable half mirror 201 to the retracted position outside the photographing optical path (the position indicated by the two-dot chain line in FIG. 1) includes an opening spring 407. The driving unit and the retracting unit are not limited to such a configuration, and other configurations may be used as long as the movable half mirror 201 can be driven.

An elastic member 421 is disposed on the body bottom surface 423 in the mirror box of the camera body 20 at a position where the mirror frame 403 comes into contact with the retracted position. The elastic member 421 acts as a buffer member when the mirror frame 403 moves to the retracted position, and substantially matches the shape of the peripheral edge of the mirror frame 403. The body bottom surface 423 surrounded by the elastic member 421 is provided with a distance sensor opening 423a as an opening for guiding the subject light flux to the distance sensor unit 451. When the movable half mirror 201 is in the retracted state, the distance sensor opening 423a is sealed by the half mirror 401, the mirror frame 403, the elastic member 421, and the body bottom surface 423.

A frame body 459 of the distance measurement sensor unit 451 is arranged below the body bottom surface 423 so that the distance measurement sensor opening 423a and the frame body opening 459a coincide with each other. In the frame 459, a mirror 453 provided at a position for reflecting the subject light beam incident through the frame opening 459a, a pair of imaging lenses 455 for imaging the subject light beam, and a distance measuring device A distance measuring sensor 457 is provided. The distance measuring sensor unit 451 is an optical system for performing known TTL phase difference distance measuring.

Next, the structure of the mirror frame 403 that holds the half mirror 401 will be described with reference to FIG. The half mirror 401 includes a shock-absorbing member 463 that functions as a shock absorber, and is fixed to the mirror frame 403 with an adhesive 461. The buffer member 463 has elasticity. In the present embodiment, the buffer member 463 is provided over the entire periphery of the peripheral portion of the half mirror 401. However, the present invention is not limited to this, and only the four corners, only the midpoint of each side, or predetermined Various arrangements such as providing at a distance interval may be used.

A modification of the holding structure of the half mirror 401 is shown in FIG. In the embodiment shown in FIG. 3A, the shock is absorbed by the buffer member 463 and the half mirror 401 is fixed to the mirror frame 403 by the adhesive 461. However, in the modified example, an elastic adhesive having both properties is used. The half mirror 401 is fixed to the mirror frame 403 using 465. This elastic adhesive 465 has a function of absorbing a stress such as external vibration or impact by becoming a rubber-like elastic body after curing. This also has a function of absorbing thermal strain such as expansion and contraction, and therefore has a characteristic that stress is not easily concentrated on the adhesive interface. A hardness of 40 to 60 (Shore A) is suitable after curing. The measurement of hardness is also defined in JIS K6253, and a general method is to push an indenter (also referred to as a push needle) into the surface of the object to be measured for deformation, and to quantify the amount of deformation.

Since the movable half mirror 201 and the distance measuring unit 451 are configured in this way, when the cam pin 415 is driven to a position in contact with the locking release position 417b by a motor (not shown), the mirror frame 403 and the locking lever 413 are moved. By the urging force of the opening spring 407, the mirror frame 403 is moved to the retracted position as shown in FIG. At this time, the opening 459a of the distance measuring sensor unit 451 is sealed by the movable mirror 201 and the elastic member 421. When the movable mirror 201 moves to the retracted position, the possibility that the user touches with a finger and a fingerprint or the like attaches or is damaged is reduced. In addition, since the elastic member 421 absorbs shock and vibration during operation when moving from the reflecting position to the retracted position, the half mirror 401 is hardly damaged. Further, since the distance measuring sensor unit 451 is covered by the movable half mirror 201, there is no fear that dust such as dust adheres. Furthermore, the shock applied to the mirror frame 403 is reduced by the buffer member 463 or the elastic adhesive 465, and the impact is not directly transmitted to the half mirror 401. For this reason, when the movable half mirror 201 moves from the reflection position to the retracted position, the possibility that the half mirror 401 is damaged by an impact can be further reduced.

In the retracted state of the movable half mirror 201, when the mirror cam 417 is rotated by the motor and the locking position 417a comes into contact with the cam pin 415, the locking lever 413 rotates clockwise (the direction opposite to the arrow B direction). The mirror frame 403 is rotated clockwise (opposite to the arrow A direction) via the drive pin 405 against the urging force of the opening spring 407 and returned to the reflection position. As a result, the movable half mirror 201 reflects part of the subject light that has passed through the lenses 101a and 101b downward, passes through the distance measuring sensor opening 423a and the frame opening 459a, is reflected by the mirror 453, and is an imaging lens. The pupil is divided by 455 and formed on the distance measuring sensor 457. Based on the output of the distance measuring sensor 457, the focus states of the lenses 101a and 101b are detected. In addition, a part of the subject luminous flux passes through the movable half mirror 201 and is guided in the direction of the CCD 221. When returning from the retracted position to the reflecting position, the positioning member is positioned by a regulating member that defines the reflecting position. The shock that occurs when the movable half mirror 201 comes into contact with the positioning regulating member is also affected by the buffer member 463 or elastic bonding. The agent 465 can reduce the risk of the half mirror 401 being damaged. Note that although the photometric element is not provided in the distance measuring unit 451 in FIG. 2, a photometric element may be provided.

By adopting a structure in which the half mirror 401 is held on the mirror frame 403 by the adhesive 461 and the buffer member 463 or the elastic adhesive 465, even if the half mirror 401 and the mirror frame 403 are expanded and contracted due to a temperature change, respectively. The buffer member 463 and the elastic adhesive 465 can prevent distortion of the half mirror 401 and the mirror frame 403.

Next, the operation of the digital camera in one embodiment of the present invention will be described using the flowcharts shown in FIGS. When the power-on reset flow shown in FIG. 4 is entered, it is determined whether the power switch 257 of the camera body 20 is turned on (S1). As a result of the determination, if the power switch 257 is off, the process proceeds to step S3 to enter a sleep state that is a low power consumption state. In this sleep state, interrupt processing is performed only when the power switch 257 is turned on, and processing for turning on the power switch is performed in step S5 and subsequent steps. Until the power switch is turned on, operations other than power switch interrupt processing are stopped to prevent the power battery from being consumed. In step S1, if the power switch 257 is on, the process proceeds to step S2, and it is determined whether the attach / detach switch 259 is off. As described above, the attachment / detachment detection switch 259 is a switch that is turned off when the lens barrel 10 is removed from the camera body 20. If it is off, that is, if the lens barrel 10 is detached, the process proceeds to step S51 described later. This is because when the power switch lever of the camera body 20 is operated and the power is turned on with the lens barrel 10 detached, the same processing as when the lens is detached is performed. If it is determined in step S2 that the detachable switch 259 is on, the process proceeds to step S5 and subsequent steps, and processing for turning on the power switch is performed.

In step S5, the movable half mirror 201 is returned. This is because the movable half mirror 201 is in a position retracted from the photographing optical path when the power switch 257 is off (in the state of the two-dot chain line in FIG. 1), but the lens barrel 10 is turned on when the power switch 257 is turned on. This is because the subject luminous flux from is guided to the distance / photometry sensor 217 to perform photometry and distance measurement. Next, a dust removing operation is performed in the dust filter 205 (S7). In this operation, a driving voltage is applied from the dust filter driving circuit 211 to the piezoelectric element 207 fixed to the dust filter 205, and dust and the like are removed by ultrasonic waves as described above.

Subsequently, the shutter driving circuit 213 performs an opening operation of the shutter 203 (S9). As a result, the subject light flux that has passed through the movable half mirror 201 is not blocked by the shutter 203, so that a subject image is formed on the CCD 221. Using the image data picked up by the CCD 221, the rear liquid crystal monitor 26 is instructed to start a through image display for displaying a subject image as a moving image (S 11). The through image display operation is controlled by the image processing circuit 227 in response to the start instruction.

Next, if there is information such as the shooting mode set by a mode dial (not shown), ISO sensitivity, manually set shutter speed, aperture value, etc., those shooting conditions are read (S13). Then, the subject brightness is measured by the distance measuring / photometric sensor 217, the exposure amount is calculated, and exposure control values such as a shutter speed and an aperture value are calculated according to the shooting mode and shooting conditions using the exposure amount (S15). . Further, through image display setting is performed using a photometric value, an exposure amount, and the like (S17). In this step, in order to set the electronic shutter speed and sensitivity conditions for driving the CCD 221, using the photometry / exposure calculation result obtained in step S15 or the previous display image, the rear liquid crystal monitor 26 and / or Alternatively, calculation and setting for displaying an image of appropriate brightness (brightness) on the liquid crystal 29 in the finder is performed.

Next, it progresses to step S19 and it is determined whether it is a reproduction | regeneration mode. This playback mode is a mode in which, when a playback button is operated, still image data recorded on the recording medium 245 is read and displayed on the rear liquid crystal monitor 26 and / or the finder liquid crystal 29. If the reproduction mode is set as a result of the determination, the process proceeds to step S31 to instruct the image processing circuit 227 to stop the through image display. Thereafter, after closing the shutter 203 (S33), the still image data recorded on the recording medium 245 is read out, the image data is expanded by the compression / expansion circuit 231, and the video signal output circuit 233 and the liquid crystal monitor are read out. The still image is reproduced and displayed on the rear liquid crystal monitor 26 and / or the finder liquid crystal 29 via the drive circuit 235 (S35). If another manual operation such as half-pressing the release button is performed during the reproduction operation, the reproduction operation is terminated, the process returns to step S7, and the above operation is repeated.

Returning to step S19, if the playback mode has not been set, the process proceeds to step S21 to determine whether the menu mode has been set. This determines whether the menu button is operated and the menu mode is set. As a result of the determination, if the menu mode is set, a through image stop instruction is output (S37) and a close command is output to the shutter 203 (S39), as in the case where the playback mode is set. Thereafter, a menu setting operation is performed (S41). Various setting operations such as white balance, ISO sensitivity setting, and drive mode setting can be performed by the menu setting operation. When the menu setting operation is completed, the process returns to step S7, and the above operation is repeated.

Returning to step S21, if the result of determination is that the menu mode has not been set, processing proceeds to step S23, where it is determined whether the release button has been pressed halfway, that is, whether the 1R switch is on. If the result of determination is that 1R is on, processing advances to step S43, and a shooting operation subroutine for shooting preparation and shooting is executed. Details of this subroutine will be described later with reference to FIG. When the photographing operation subroutine ends, the process returns to step S7 and the above-described steps are repeated.

Returning to step S23, if the result of determination is that the 1R switch is off, processing proceeds to step S25, where it is determined whether the attachment / detachment detection switch 259 is off, as in step S2. When the lens barrel 10 is detached, a through image stop instruction is output (S45) and the shutter 203 is closed (S47), as in steps S31 and S33 in the reproduction mode. Thereafter, the retracting operation of the movable half mirror 201 is performed (S49). As described above, the retracting operation is performed by driving the motor to rotate the mirror cam 417 and rotating the mirror frame 403 to the position retracted from the photographing optical path by the biasing force of the opening spring 407 (FIG. 1). Of the two-dot chain line). As described above, since the elastic member 421 is provided at the retracted position of the movable half mirror 201, the elastic member 421 functions as a buffer member, so that the impact can be reduced and damage can be prevented. Further, the shock can be reduced by the buffer member 463 and the elastic adhesive 465.

When the retracting of the movable half mirror 201 is completed, or when it is determined in step S2 that the attachment / detachment detection switch 259 is off (that is, when the lens barrel 10 is detached), the process proceeds to step S51. It is determined whether or not the detection switch 259 is on. In step S25, after detecting that the lens barrel 10 is detached, it is determined whether or not the lens barrel 10 is attached again. As a result of the determination, if it is mounted, the process proceeds to step S55, and the movable half mirror 201 is returned. As described above, the mirror cam 417 is rotated by driving the motor, the locking lever 413 is rotated clockwise by the cam surface against the urging force of the opening spring 407, and the mirror frame. 403 is inserted in the optical path of the lenses 101a and 101b. When the return of the movable half mirror 201 is completed, the process returns to step S7, and the above steps are repeated.

Returning to step S51, if the attachment / detachment detection switch 259 is off, the process proceeds to step S53 to determine whether the power switch 257 is on. When the lens barrel 10 is detached and the power switch 257 is on, the mount opening remains open even when various operation buttons are operated. Therefore, from the viewpoint of preventing malfunction, the camera operation should not be performed. Yes. For this reason, in step S51, the lens barrel 10 is mounted, and in step S53, the standby state in which the determination of the power switch lever operation state is repeated. If it is determined in step S53 that the power switch 257 is off, the process returns to step S3 to enter a sleep state. In step S51, when it is detected that the lens barrel 10 remains detached, the determination in step S53 may be omitted, and the process may proceed to step S3 to enter the sleep state, or the process may proceed to step S9. Modifications such as performing an operation based on an operation by the operation button are possible.

Returning to step S25, if the result of determination is that the attachment / detachment detection switch 259 is on, that is, if the lens barrel 10 is attached to the camera body, the routine proceeds to step S27, where it is determined whether or not the power switch 257 is on. If the result of determination is that it is on, processing returns to step S13 and the above steps are repeated. In step S11, after the through image display is started, the subject light flux that has passed through the movable half mirror 201 is not blocked by the shutter 203 unless various operation buttons are operated in step S19 and subsequent steps. The image data picked up by the CCD 221 is displayed as a moving image on the rear liquid crystal monitor 26 and / or the finder liquid crystal 29 as a moving image. If it is determined in step S27 that the power switch 257 is off, as in steps S31 and S33, the image processing circuit 227 is instructed to stop displaying the through image (S28), and the shutter 203 is closed. (S29). Thereafter, similarly to step S49 described above, after the retracting operation of the movable half mirror 201 is performed (S30), the process returns to step S3 and enters the sleep state. As described above, since the elastic member 421 is provided at the retracted position of the movable half mirror 201, the elastic member 421 functions as a buffer member, so that the impact can be reduced and damage can be prevented. Further, the shock can be reduced by the buffer member 463 and the elastic adhesive 465.

As described above, in this embodiment, in a digital camera capable of displaying a through image, the movable half mirror 201 is inserted into the photographing optical path when the camera is operated, and a part of the subject light flux is reflected to the distance measuring / photometric sensor 217. Therefore, when the release button is pressed halfway during live view display and 1R is turned on, photometry and distance measurement can be performed immediately in parallel with live view display.

In the power-on reset routine, when the attachment / detachment detection switch 259 detects that the lens barrel 10 is detached (S25), the movable half mirror 201 is retracted from the photographing optical path, and the lens barrel 10 is remounted. When this is detected by the attachment / detachment detection switch 259 (S51), the movable half mirror 201 is inserted into the photographing optical path. Therefore, when the lens barrel 10 is removed and the mount portion is in the open state, the movable half mirror 201 is in the retracted state even if a user or the like tries to insert a cleaning tool or the like from the mount opening portion. There is no possibility that the movable half mirror 201 is damaged or a fingerprint is attached.

Further, even when the lens barrel 10 is removed at the time of power-off, the movable half mirror 201 is in the retracted state. Similarly, the movable half mirror 201 is damaged or a fingerprint is attached by the user or the like. There is no fear of. When the camera is powered on, the movable half mirror 201 is inserted in the photographing optical path, so that the distance measurement operation and the photometry operation can be performed in parallel with the through image display operation.

Further, when the movable half mirror 201 is retracted (S30, S49), the movable half mirror 201 is in contact with the elastic member 421, so that the shock applied to the very thin half mirror 401 can be eased, and thus the breakage occurs. The risk of doing so can be reduced. Further, when the movable half mirror 201 is retracted (S30, S49) and when the movable half mirror 201 is restored (S7, S30, S55), the shock is reduced by the buffer member 463 or the elastic adhesive 465. The possibility that the half mirror 401 is damaged can be reduced.

Next, the shooting operation subroutine of step S43 will be described with reference to FIG. As described above, this subroutine is executed when the release button is half-pressed. First, distance measurement and automatic focus adjustment are performed (S71). This is because the movable half mirror 201 is inserted in the photographing optical path, and a part of the subject luminous flux is reflected to the distance measuring / photometric sensor 217, so that the subject measuring luminous flux is used to measure the distance measuring / photometric processing circuit 219 and the body. The CPU 229 and the like detect the focus shift amounts of the lenses 101a and 101b by the TTL phase difference method, and the lenses 101a and 101b are brought into focus by the optical system drive mechanism 107 via the lens CPU 111 based on the detected focus shift amounts. Drive.

Next, photometry / exposure amount calculation is performed (S73). The subject light flux reflected by the movable half mirror 201 is also received by the distance measurement / photometry sensor 217 and processed by the distance measurement / photometry processing circuit 219, thereby detecting the subject brightness BV. The body CPU 229 obtains the exposure amount EV using the subject luminance BV, and further obtains the exposure conditions such as the shutter speed and the aperture according to the photographing mode.

Next, it is determined whether or not the release button has been fully pressed, that is, whether or not 2R is on (S75). If the result of determination is that it is off, processing advances to step S77 to determine whether 1R is on. If the release button is half-pressed to jump to this shooting operation subroutine, and the release button remains half-pressed, a standby state is made in which the determination is repeated in steps S75 and S77. When the hand is released from the release button and 1R is turned off, the process returns to the power-on reset step S9.

Returning to step S75, if the result of determination is that the 2R switch is on, that is, if the release button is fully pressed, the operation moves to an imaging operation for acquiring a still image. First, in step S79, a through image stop instruction is output to the image processing circuit 227. This is due to the movement of the movable half mirror 201 to the retracted position and the opening / closing operation of the shutter 203 during the acquisition of the still image, causing the subject image incident on the CCD 221 to be disturbed, and in the rear liquid crystal monitor 26 and / or the liquid crystal 29 in the viewfinder. This is to prevent the through image from becoming unsightly. Subsequently, the retracting operation of the movable half mirror 201 is performed in the same manner as in step S49 (S81). As described above, since the elastic member 421 is provided at the retracted position of the movable half mirror 201, the elastic member 421 functions as a buffer member, so that the impact can be reduced and damage can be prevented. Further, the shock can be reduced by the buffer member 463 and the elastic adhesive 465.

Subsequently, the aperture driving mechanism 109 performs the aperture operation of the aperture 103 to the set aperture value or the aperture value calculated in S73 through the lens CPU 111. When the narrowing-down operation is completed, an exposure operation by the CCD 221 is then performed (S85). That is, since the movable half mirror 201 has moved to the retracted position, all of the subject luminous flux that has passed through the lenses 101 a and 101 b forms an image on the CCD 221. In this state, the reset of the electronic shutter of the CCD 221 is released, and charge accumulation of the photoelectric conversion current of the subject image is started. When the exposure time set in advance or set in step S73 has elapsed, the electronic shutter of the CCD 221 stops the charge accumulation of the photoelectric conversion signal. In the exposure operation in step S85, the exposure time is controlled by the electronic shutter of the CCD 221. However, the present invention is not limited to this, and the exposure time can also be controlled by the shutter 203. In this case, it is necessary to once move the front and rear curtains of the shutter 203 to the initial positions before the start of the exposure operation.

Subsequently, the shutter 203 is closed (S87), and an instruction to open the aperture 103 is output to the lens CPU 111 (S89). Further, the image signal stored in the CCD 221 is read (S91), and image processing is performed by the image processing circuit 227 or the like (S93). After processing such as signal compression in the compression / decompression circuit 231, image data is recorded on the recording medium 245 (S95). When the recording of the image data is finished, it is determined in step S97 whether the 1R switch is on, that is, whether the release button is half pressed. When the 1R switch is turned off, the process proceeds to step S99, and the return operation of the movable half mirror 201 is performed in the same manner as in step S55. When the return operation is completed, the routine returns to the power-on reset routine.

In the shooting operation subroutine of the present embodiment, the movable half mirror 201 is retracted during an imaging operation for acquiring a still image. For this reason, a decrease in the amount of transmitted light in the movable half mirror 201 is eliminated, the amount of subject light can be increased in acquiring a still image, and photographing at a high shutter speed is possible. Further, when the imaging operation is completed, the movable half mirror 201 is returned in step S99. Therefore, when the release button is half-pressed again after photographing, photometry and distance measurement are immediately performed in parallel with the live view display. be able to.

As described above, in this embodiment, since the elastic member 421 is disposed on the body bottom 423 of the mirror box with which the movable half mirror 201 abuts, the movable half mirror 201 is moved to the retracted position. The abutting on the bottom 423 of the body can reduce the possibility that the half mirror 401 will be damaged by the impact. Further, when it is in the retracted position, it becomes difficult for the user to touch the movable half mirror 201 with a finger, and even if it is touched, the impact can be reduced by the elastic member 421, so that the possibility of breakage can be reduced. .

In the present embodiment, when the movable half mirror 201 is retracted, the distance measuring sensor unit 451 is covered by the movable half mirror 201, so that the distance measuring sensor 457 is not exposed and the risk of dust or the like being attached is reduced. can do. Furthermore, since it is sealed by the elastic member 421 or the like, there is no possibility that dust will enter through the gap.

Further, in the present embodiment, since the buffer member 463 or the elastic adhesive 465 is interposed between the half mirror 401 and the mirror frame 403, the impact applied to the mirror frame 403 is directly applied to the half mirror 401. The possibility that the very thin half mirror 401 is not damaged can be reduced. In general, since the thickness of the half mirror is very thin, 0.4 mm or less, it is important to reduce the impact during operation.

In this embodiment, since the buffer member 463 or the elastic adhesive 465 is interposed between the half mirror 401 and the mirror frame 403, due to the difference in thermal expansion coefficient between the half mirror 401 and the mirror frame 403, respectively. Even if it expands and contracts by different amounts, the buffer member 463 or the elastic adhesive 465 can absorb the strain.

In this embodiment, in order to reduce the impact on the movable half mirror 201,
1.
An example in which an elastic member 421 is disposed on the bottom surface 423 of the body with which the movable half mirror 201 abuts (see FIG. 2).
2.
An example in which a member for absorbing an impact is provided between the half mirror 401 and the mirror frame 403 (see FIG. 3).
However, it does not matter if only one of them is employed, and the impact can be absorbed sufficiently.

In the present embodiment, the elastic member 421 is disposed on the body bottom surface 423. However, the elastic member 421 is not limited to this, and for example, the elastic member 421 may be disposed at a position where the movable half mirror 201 is in contact with the reflective position. Absent. Furthermore, although the elastic member 421 is disposed on the body bottom surface 423, it is of course possible to embed the entire elastic member 421 in the body bottom surface 423 or to embed a part thereof.

In the present embodiment, the CCD 221 serving as an image sensor receives light transmitted through the movable half mirror 201, and the distance measurement / photometry sensor 217 receives light reflected from the movable half mirror 201. May be configured to receive reflected light and the ranging / photometric sensor 217 to receive transmitted light.

In the present embodiment, the present invention is applied to a general digital camera. However, the present invention is not limited to this, and may be a photographing device in various devices such as a portable device, and is equipped with a bellows, an extension tube, or the like. Of course, the present invention can also be applied to a dedicated camera attached to various devices such as a microscope and binoculars. Further, the mirror device is not limited to a digital camera, and can be applied to any device that can be applied to a device that receives an impact on a movable half mirror.

It is a block diagram which shows the whole structure of the electric system of the digital camera in one Embodiment to which this invention is applied. It is a figure which shows the components structure of the movable half mirror and ranging unit in one Embodiment of this invention, (A) is an external appearance perspective view of a movable half mirror, (B) is a movable half mirror containing a ranging unit. It is XX sectional drawing. It is YY partial expanded sectional view of the movable half mirror in one Embodiment of this invention, (A) is one Embodiment of this invention, (B) is a modification of one Embodiment. It is a flowchart which shows the operation | movement of the power-on reset in one Embodiment of this invention. 6 is a flowchart of a shooting operation according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Lens barrel 20 Camera main body 26 Back surface liquid crystal monitor 29 Liquid crystal monitor 101a, 101b in finder Lens 103 Diaphragm 111 Lens CPU
201 Movable Half Mirror 203 Shutter 205 Dustproof Filter 207 Piezoelectric Element 215 Movable Mirror Drive Mechanism 217 Distance / Metering Sensor 219 Distance / Metering Processing Circuit 221 CCD
227 Image processing circuit 229 Body CPU
253 Switch detection circuit 255 Various switches 257 Power switch 259 Attachment / detachment detection switch 401 Half mirror 403 Mirror frame 421 Elastic member 423 Body bottom surface 451 Distance sensor unit 457 Distance sensor 459 Frame body 459a Frame body opening 461 Adhesive 463 Buffer member 465 Elastic adhesive

Claims (8)

A movable mirror that can move back and forth in the optical path of the photographic lens, and that reflects the subject luminous flux in the optical path;
A distance measuring sensor unit including a distance measuring sensor for detecting a focus state of the photographing lens by a subject luminous flux reflected by the movable mirror;
A buffer member that contacts when the movable mirror is retracted from the optical path;
The digital camera is characterized in that the buffer member is disposed around the opening of the distance measuring sensor unit.   The digital camera according to claim 1, wherein the movable mirror seals the opening of the distance measuring sensor unit when abutting against the buffer member.   2. The digital camera according to claim 1, wherein the photographic lens is replaceable, and the movable mirror moves to a position where it comes into contact with the buffer member in response to removal of the photographic lens.   The digital camera according to claim 1, wherein the movable mirror includes a mirror member and a holding member that holds the mirror member, and the holding member abuts on the buffer member. A movable half mirror that is disposed in a mirror box in the camera body, can be moved back and forth in the optical path of the photographic lens, reflects a part of the subject luminous flux in the optical path, and transmits other luminous flux;
A buffer member disposed in the mirror box at a position in contact with the movable mirror;
A digital camera comprising:   The digital camera according to claim 5, wherein the buffer member is disposed at a bottom portion of the mirror box and abuts on the movable mirror when the movable half mirror is in a retracted state.   The digital camera according to claim 5, wherein the buffer member has a shape along a shape of a peripheral edge of the movable half mirror.   A distance measuring sensor unit including a distance measuring sensor for detecting a focus state of the photographing lens by a subject light beam reflected by the movable mirror, and when the movable half mirror is in a retracted state, The digital camera according to claim 5, wherein the digital camera covers the opening.