JP2008017104A - Digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve various problems caused by a half-mirror in a digital camera in which the half-mirror is disposed. <P>SOLUTION: The digital camera has the half-mirror which has a plurality of fine holes 401a to reflect part of incident luminous flux and passes the rest, a range-finding/photometry sensor which receives the luminous flux reflected by the half-mirror 401, and a CCD 221 which receives the luminous flux passed through the plurality of fine holes 401a. Through image display is performed with the passing luminous flux from the half-mirror 401, and range-finding and photometry are performed with the reflected luminous flux from the half-mirror 401. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a digital camera having a half mirror that divides a subject luminous flux from a photographing lens.

Some conventional photographing apparatuses employ a half mirror to divide a subject luminous flux into two systems, such as an image recording system such as a film and an image sensor, and a viewfinder optical system. Some recent digital cameras have a through image display function (also referred to as a live view display function or an electronic viewfinder function). This function is to display the output of an image sensor provided for recording of subject image data on a display device such as a liquid crystal monitor for observing the subject image.

As a digital camera having such a through image display function, for example, in Patent Document 1, a movable mirror is configured by a half mirror, and a subject light flux that has passed through a photographing optical system is guided to both an image sensor and a phase difference AF sensor. Such a digital camera has been proposed. According to this configuration, phase difference AF is also possible while displaying a through image. As described above, Patent Document 1 discloses that a subject luminous flux is divided using a half mirror.
Japanese Patent Laid-Open No. 2002-6208

As in Patent Document 1, if the half mirror is inclined and arranged in the photographing optical path, the following problem occurs. Glass is generally used as the material of the half mirror. However, the glass material has problems such as deterioration in image quality, defocus, and image distortion of an image obtained by the image sensor due to the relationship between the refractive index and thickness. In order to avoid this problem, a glass plate that is as thin as possible and has a low refractive index is required. However, since a glass plate that satisfies this requirement is very easy to break, handling is troublesome, and various measures such as providing a buffer material for the frame structure that holds the glass plate are required.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a digital camera in which various problems caused by a glass half mirror are solved in a digital camera having a half mirror.

In order to achieve the above object, a digital camera according to a first invention has a plurality of minute holes, reflects a part of an incident light beam and passes the remaining part, and a light beam reflected by the half mirror. A first light receiving sensor for receiving light and a second light receiving sensor for receiving the light flux that has passed through the plurality of micro holes.

In the digital camera according to the second invention, in the first invention, the half mirror is made of metal.
In the digital camera according to a third aspect of the present invention, in the first aspect, the first sensor is a distance measuring sensor, and the second light receiving sensor is an image sensor.
Furthermore, in the digital camera according to the fourth invention, in the first invention, the reflective surface of the half mirror is provided with a reflective coating.

Furthermore, in the digital camera according to a fifth aspect of the present invention, in the first aspect, the microhole is perforated at an angle and a diameter so as not to block the principal ray at each position on the surface.
Furthermore, in the digital camera according to a sixth aspect of the present invention, in the first aspect, the reflectance of the half mirror is determined by the diameter and interval of the minute holes.
Furthermore, in the digital camera according to a seventh aspect of the present invention, in the first aspect, the half mirror can be moved back and forth with respect to the photographing optical path.

In order to achieve the above object, an imaging apparatus according to an eighth aspect of the present invention is capable of splitting the light beam from the shooting optical system in two directions, the imaging means capable of shooting the light beam from the shooting optical system, and the divided one. Half mirror means for guiding a light beam in the direction to the imaging means is provided, and the half mirror is composed of a plurality of minute holes and a reflection portion on the surface.
It comprises.

According to a ninth aspect of the present invention, in the eighth aspect of the invention, the minute hole is formed at an angle so as not to interfere with the principal ray at each position on the surface of the half mirror.
According to a tenth aspect of the present invention, in the eighth aspect, the microhole is perforated with a diameter corresponding to a distance from the imager.
Further, in the photographing apparatus according to the eleventh aspect of the invention, in the eighth aspect of the invention, the reflectance of the half mirror is determined by the diameter and interval of the minute holes.
Further, in the photographic device according to the twelfth invention, in the eighth invention, the back surface of the half mirror means and / or the minute hole is prevented from being reflected.
Furthermore, a photographing apparatus according to a thirteenth aspect of the present invention includes a display means for displaying a subject image based on the data imaged by the imaging means in the eighth aspect of the invention.
Furthermore, in the photographing apparatus according to the fourteenth invention, in the eighth invention, the micro holes are irregularly arranged.

According to the present invention, a half mirror that has a plurality of minute holes, reflects a part of the incident light beam, and passes the remaining part is provided. A solved 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. It should be noted that the camera body 20 and the lens barrel 10 may be integrally configured, and in that case, the attachment / detachment detection switch 259 is unnecessary.

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 the mirror box in the camera body 20, a movable reflecting mirror 201 (referred to as a movable half mirror for convenience) 201 having a characteristic that a part of the light beam that has passed through the lenses 101a and 101b is reflected and a part of the light passes is disposed. ing. The movable half mirror 201 is a metal thin film mirror having a reflective surface and a large number of minute holes. The presence of these minute holes performs the same function as a general half mirror. The movable half mirror 201 is driven by a movable mirror drive mechanism 215, and can be rotated about an axis of rotation about a rotation axis 201a. When the movable half mirror 201 is at a position inclined by 45 degrees with respect to the optical path of the lenses 101a and 101b (the position indicated by the solid line in FIG. 1), a part (for example, 35%) 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. The remainder (for example, 65%) 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 in a retracted position (a position indicated by a two-dot chain line in FIG. 1) that does not block the subject light beam, the entire subject light beam is guided to the CCD 221. The structure and drive mechanism of the movable half mirror 201 will be described later with reference to FIGS.

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. Moreover, although the rotation center of the movable half mirror 201 is arranged on the CCD 221 side, it is not limited to this and may be arranged on the mount opening side. Furthermore, in the present embodiment, the reflectance and the transmittance of the half mirror are 35% and 65%, 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 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 the subject image formed by the lenses 101a and 101b is photoelectrically converted into an electrical signal. 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 and retracting means of the movable half mirror 201 will be described with reference to FIG. A metal thin film mirror 401 that passes a part of the subject light flux and reflects a part thereof is held by a mirror frame 403. The mirror frame 403 is rotatable around a shaft 411 inserted in the hole 403 a, and the rotation shaft 201 a in FIG. 1 is a central axis of the shaft 411. 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. 2) 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.

Since the movable half mirror 201 is 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 opened and the spring 407 is attached. The mirror frame 403 is moved to the retracted position as shown by a two-dot chain line in the figure by the force. In this state, 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 is rotated in the clockwise direction (the direction opposite to the arrow B direction), and the opening spring 407 is rotated. The mirror frame 403 is rotated clockwise (opposite to the direction of the arrow A) via the drive pin 405 against the urging force, and is positioned at a reflection position as shown by a solid line in the drawing.

Next, the structure of the metal thin film mirror 401 will be described with reference to FIG. 3A is a cross-sectional view of the metal thin film mirror 401, and FIG. 3B is a plan view. The metal thin film mirror 401 is a plate made of a metal such as titanium or aluminum having a thickness of about 0.05 mm, and the surface of an opaque metal material is subjected to a mirroring process by aluminum vapor deposition. As shown in FIGS. 3A and 3B, a minute hole 401a having a surface diameter of about 0.2 mm to 0.5 mm is provided. The minute holes 401a are arranged so as to form an equilateral triangle when the centers of these minute holes 401a are connected. The back surface and the inside of the minute hole 401a are completely matted with black paint or the like to prevent unnecessary reflection.

As shown in FIG. 4, the transmittance and the reflectance of the metal thin film mirror 401 can be changed by the diameter of the minute holes 401a and the hole interval (distance from the edge of the hole to the edge of the adjacent hole). In this embodiment, the passing rate is 65% and the reflectance is 35%. This can be achieved by setting the hole interval to 0.181, where the hole diameter of the minute hole 401a is 1. In addition to this, for example, in order to obtain a pass rate of 50% and a reflectivity of 50%, assuming that the diameter of the microhole 401a is 1, the hole interval may be set to 0.346. What is necessary is just to determine the diameter and space | interval of a hole according to a rate.

FIG. 5 shows a modification of the metal thin film mirror 401. In the embodiment, the minute hole 401a of the metal thin film mirror 401 is formed at a right angle to the mirror surface. In this modification, as shown in FIG. Perforations are provided by punching out the micro holes 401b at angles and diameters that do not block the principal rays 501a, 501b, and 501c. That is, the minute hole 401b is perforated with a diameter corresponding to the distance from the imager (CCD 221) at an angle different from each position in the plane so as not to emit the principal ray. In FIG. 5, three micro holes 401b are schematically drawn. However, in practice, a large number of micro holes are arranged, and the angle and diameter of the perforations are determined so as not to block the chief rays for each micro hole. .

Next, the operation of the digital camera in one embodiment of the present invention will be described using the flowchart shown in FIG. If the power-on reset flow 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. When the movable half mirror 201 returns, the subject light beam reflected by the reflecting surface of the metal thin film mirror 401 is reflected by the distance measuring / photometric sensor 217, while the subject light beam passing through the micro holes 401a and 401b of the metal thin film mirror 401 passes through. Guided in the direction of the shutter 203. 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 micro holes 401 a and 401 b of 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. In this shooting operation subroutine, photometry and distance measurement can be performed based on a part of the subject luminous flux reflected by the movable half mirror 201 in parallel with the live view display. When 2R is turned on, the movable half mirror 201 is retracted, all of the subject light flux is guided onto the CCD 221, and image data based on the output of the CCD 221 is recorded on the recording medium 245. 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).

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 operation state of the power switch lever 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. After the through image display is started in step S11, the subject light flux that has passed through the micro holes 401a and 401b of the metal thin film mirror 401 is not blocked by the shutter 203 unless various operation buttons and the like are operated in step S19 and subsequent steps. A subject image is formed on the CCD 221, and image data captured 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, in the present embodiment and the modification thereof, the micro holes 401a and 401b are provided in the metal thin film mirror 401, and the through image formed based on the output of the imager (CCD 221) is the micro hole (in the air). Formed by the luminous flux of the subject passing through. For this reason, it is hard to break compared with a glass half mirror, and is easy to handle. Further, there is an advantage that it is difficult to be affected by dust, dust, etc. adhering to the metal thin film mirror 401.

In the present embodiment and its modification, the movable half mirror 201 is inserted in the photographing optical path during live view display, and the subject light flux that has passed through the minute holes 401a and 401b forms an image on the CCD 221. The half mirror 201 is retracted from the photographing optical path, and the subject light beam forms an image directly on the CCD 221. There is no change in the optical path length to the CCD 221 at the time of displaying and photographing this through image, so that there is no focus shift in both.

Furthermore, in the present embodiment and its modifications, when passing through a glass half mirror, the optical path length at the half mirror differs depending on the incident angle, so the amount of aberration generated differs and image degradation occurs. End up. However, in this embodiment, since the microscopic hole passes through and does not change to the optical path length, image deterioration due to the metal thin film mirror 401 does not occur.

Further, since the back surface of the metal thin film mirror 401 and the inside of the micro holes 401a and 401b are subjected to a cancellation process so as not to generate reflected light, the metal thin film is moved when the movable half mirror 201 is moved to the raised position by mirror up. Reflection by the back surface of the mirror 401 does not occur. For this reason, stray light does not enter the CCD 221 at the time of photographing, and ghost or the like does not occur.

Further, in the present embodiment, in a digital camera capable of displaying a through image, the movable half mirror 201 is inserted in the photographing optical path when the camera is operated, and a part of the subject luminous 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 this embodiment, a metal such as aluminum or titanium is used as the material of the metal thin film mirror 401. However, the present invention is not limited to this, and a resin or the like may be used as long as it is a light and durable material. . In addition, the arrangement of the minute holes is such that the center point of the hole constitutes an equilateral triangle with the adjacent minute hole. However, the present invention is not limited to this, and the minute holes can be appropriately arranged, or may be randomly arranged. I do not care. By arranging them irregularly, it is possible to prevent moiré images that occur in relation to pixel pits. The transmittance and reflectance in the case of irregular arrangement can be obtained from the average diameter of the minute holes, the average distance to the adjacent minute holes, and the like.

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

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 disassembled perspective view which shows the components structure of the movable half mirror in one Embodiment of this invention. It is a figure which shows the half mirror in one Embodiment of this invention, (A) is sectional drawing, (B) is a top view. It is a figure explaining the micro hole of the half mirror in one Embodiment of this invention, a transmittance | permeability, and a reflectance. It is sectional drawing which shows the modification of the half mirror of one Embodiment of this invention. It is a flowchart which shows the operation | movement of the power-on reset in one Embodiment of this 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 / Photometric Sensor 219 Distance / Photometric Processing Circuit 221 CCD
227 Image processing circuit 229 Body CPU
253 Switch detection circuit 255 Various switches 257 Power switch 259 Detachment detection switch 401 Metal thin film mirror 401a, 401b Micro hole 403 Mirror frame

Claims (14)

A half mirror having a plurality of minute holes, reflecting a part of the incident light beam and passing the rest,
A first light receiving sensor for receiving the light beam reflected by the half mirror;
A second light receiving sensor for receiving a light beam that has passed through the plurality of micro holes;
A digital camera comprising:   The digital camera according to claim 1, wherein the half mirror is made of metal.   The digital camera according to claim 1, wherein the first sensor is a distance measuring sensor, and the second light receiving sensor is an image sensor.   The digital camera according to claim 1, wherein a reflective coating is applied to a reflective surface of the half mirror.   2. The digital camera according to claim 1, wherein the minute hole is formed at an angle and a diameter so as not to block the chief ray at each position on the surface. The digital camera according to claim 1, wherein the reflectance of the half mirror is determined by the diameter and interval of the minute holes.   The digital camera according to claim 1, wherein the half mirror is movable back and forth with respect to the photographing optical path. Imaging means capable of photographing the light flux from the photographing optical system;
A half mirror means capable of splitting the light beam from the photographing optical system in two directions, and guiding the divided light beam in one direction to the imaging means;
In a photographing apparatus comprising:
The half mirror is composed of a plurality of minute holes and a reflection part on the surface.   9. The photographing apparatus according to claim 8, wherein the minute hole is formed at an angle so as not to disturb a principal ray at each position on the surface of the half mirror.   9. The photographing apparatus according to claim 8, wherein the minute hole is formed with a diameter corresponding to a distance from an imager.   The imaging apparatus according to claim 8, wherein the reflectance of the half mirror is determined by the diameter and interval of the minute holes. 9. The photographing apparatus according to claim 8, wherein the back surface of the half mirror means and / or the minute hole is prevented from being reflected. Display means for displaying a subject image based on data imaged by the imaging means;
The photographing apparatus according to claim 8, further comprising:   The photographing apparatus according to claim 8, wherein the micropores are irregularly arranged.