JP2010016762A - Camera - Google Patents

Abstract

A structure and mechanism are simplified to reduce the size.
An imaging device having a first pixel that outputs a focus detection signal based on light passing through a photographing lens and a second pixel that outputs an image signal based on light passing through the photographing lens. The photographic lens can be moved between a first position set in the optical path from the photographic lens 3 to the image sensor 8 and a second position set in a position retracted from the optical path. The half mirror 6 for dividing the light through 3 into reflected light and transmitted light, and when the half mirror 6 is positioned at the first position, photometry is performed based on the image signal and based on the focus detection signal And control means 20 for performing focus detection.
[Selection] Figure 1

Description

  The present invention relates to a camera.

  When using the optical viewfinder, the reflected light from the main mirror is received by the photometric sensor in the viewfinder and photometry is performed. When using Live View, the transmitted light from the main mirror is received by the image sensor to perform photometry. There is known a single-lens reflex digital camera in which reflected light is received by an AF (Auto Focus) sensor to perform focus detection (see, for example, Patent Document 1).

Prior art documents related to the invention of this application include the following.
JP 2005-292525 A

  However, in the conventional single-lens reflex digital camera described above, a photometric sensor is installed on the viewfinder side, a focus detection optical system and an AF sensor are installed on the lower part of the camera body, and the positions of the main mirror and sub mirror are changed in a complicated manner by the drive mechanism. Since the subject light from the lens is distributed to the photometric sensor, the image sensor, and the AF sensor, there is a problem that the structure and mechanism are complicated and it is difficult to miniaturize the camera.

(1) The invention according to claim 1 is a first pixel that outputs a signal used for focus detection based on light through the photographing lens, and a second pixel that outputs an image signal based on the light through the photographing lens. And a second position set in a position retracted from the optical path, and is positioned at the first position. And optical path dividing means for dividing the light through the photographing lens into reflected light and transmitted light, and when the optical path dividing means is located at the first position, photometry is performed based on the image signal and used for focus detection It is a camera provided with the control means which performs a focus detection based on a signal.
(2) The invention of claim 2 is the camera according to claim 1, further comprising display means capable of displaying an image based on the image signal, and the control means is configured such that when the optical path dividing means is located at the first position, The image is displayed by the display means.
(3) The invention of claim 3 outputs a first pixel that outputs a signal used for focus detection by a phase difference detection method based on light through the photographing lens, and an image signal based on the light through the photographing lens. An image sensor having a second pixel, a control unit that performs focus detection based on a signal used for focus detection, performs photometry based on an image signal, and a display unit that displays an image based on the image signal. It is a camera equipped.
(4) According to a fourth aspect of the present invention, in the camera according to any one of the first to third aspects, the first pixel and the second pixel of the imaging device are arranged in substantially the same screen.
(5) The invention of claim 5 is the camera according to any one of claims 1 to 4, wherein the imaging device has a first pixel group in which a plurality of first pixels are arranged side by side, and is controlled. The means performs photometry based on the image signal from the second pixel arranged around the first pixel group.
(6) The invention of claim 6 is the camera according to any one of claims 1 to 5, further comprising designation means for designating a range for performing photometry in the image sensor, and the control means is designated by the designation means. When the first pixel is included in the range, the photometry is performed based on the image signal from the second pixel arranged around the first pixel.
(7) According to a seventh aspect of the present invention, in the camera according to any one of the first to sixth aspects, an opening that is disposed between the imaging element and the photographing lens and transmits a light beam from the photographing lens; A shutter member having a spring member for opening and closing the opening, and when the shutter member performs at least one of photometry and focus detection, charging of the spring member is completed, and the opening is opened. To do.

  According to the present invention, the structure and mechanism of a digital camera can be simplified, and downsizing can be achieved.

  FIG. 1 is a cross-sectional view of a digital camera according to an embodiment, and FIG. 2 is a diagram illustrating an electrical configuration of the digital camera according to the embodiment. First, in FIG. 1, a lens barrel 2 is detachably attached to the camera body 1. The lens barrel 2 is provided with a photographic lens (including a focusing lens) 3, a focusing lens drive control device 4, a diaphragm 5, and the like. On the other hand, the camera body 1 includes a main mirror 6, a focal plane shutter 7, an image sensor 8, a monitor 9, a main mirror rotating shaft 10, a viewfinder screen 11, a penta roof prism 12, an eyepiece lens 13, a viewfinder eyepiece window 14, and a live view switch 15. Etc. are installed.

  The main mirror 6 is a half mirror that reflects part of the subject light from the photographing lens 3 to the viewfinder side and transmits the other part to the image sensor 8 side. The main mirror 6 is driven to rotate about the rotation axis 10 by the main mirror driving device 17 and is placed in the photographing optical path shown by a solid line in FIG. 1 when not photographing, and is retracted from the photographing optical path during photographing and broken in FIG. Is placed at the position 6a. The focal plane shutter 7 includes a front curtain 7a and a rear curtain 7b, and the aperture 7c can be opened when the front curtain 7a and the rear curtain 7b are charged.

  FIG. 3 is a front view showing a focus detection pixel array portion of the image sensor 8. The image sensor 8 includes a plurality of phase difference detection type focus detection pixels 313 and 314 in a Bayer array of RGB imaging pixels 310. The RGB imaging pixel 310 captures a subject image formed by the photographing lens 3 at the time of photographing, image information necessary for calculating photometric information for AE (Auto Exposure) at the time of non-photographing, and live information described later. An image signal for generating a view image is output. As described above, the image sensor 8 can output a signal for live view, photometry, and focus detection during non-shooting. The array of focus detection pixels 313 and 314 is provided corresponding to the focus detection area 101 set on the photographing screen 100 as shown in FIG. Note that the shape and the number of focus detection pixels or the position and number of focus detection areas are not limited to this embodiment.

  The monitor 9 is a display device that displays images, characters, symbols, and the like, and displays captured images and shooting information, and also performs live view display. In this embodiment, an example in which an LCD is used for the monitor 9 is shown. The live view is a function for displaying a subject image continuously captured by the image sensor 8 at the time of non-photographing on the monitor 9 as a through image, and the photographer can determine the composition while looking at the monitor image without looking through the viewfinder. it can. This live view starts when the photographer turns on the live view switch 15 provided on the back of the camera body 1. The operation when the live view switch 15 is turned off and no live view display is performed is performed when the live view switch 15 is turned on and the live view display is performed except that the live view display is not performed on the monitor 9. Same as operation.

  A known optical viewfinder including a viewfinder screen 11, a penta roof prism 12, an eyepiece lens 13, a viewfinder eyepiece window 14, and the like is provided on the upper portion of the camera body 1, and is reflected by the main mirror 6 to form an image on the viewfinder screen 11. The captured subject image can be viewed through the viewfinder eyepiece window 14. Note that the digital camera of this embodiment always displays a viewfinder image from the viewfinder eyepiece window 14 except when shooting is performed in which the main mirror 6 is retracted from the shooting optical path, regardless of whether the live view is displayed on the monitor 9. It can be visually recognized.

  Next, in FIG. 2, the image picked up by the image pickup device 8 is subjected to various processes by the image processing circuit 21 to generate a recording image and a through image. The control device 20 includes a CPU 20a, a memory 20b, and the like, executes various calculations such as a focus detection calculation and exposure calculation (photometry calculation) of the digital camera, and various controls such as sequence control, and the focusing drive control device 4 and the image sensor 8. The shutter drive control device 22, the aperture drive control device 23, the main mirror drive device 17, the monitor display control circuit 24, the image recording device 25, and the like are controlled. The focus detection calculation and the photometry calculation are executed by the control device 20. However, the focus detection calculation and the photometry calculation are performed using a calculation device different from the control device 20, and the calculation result is output to the control device 20. It is good as well.

  FIG. 5 is a time chart illustrating the operation of the digital camera according to the embodiment, and FIG. 6 is a diagram illustrating the operation of the focal plane shutter. The operation of the embodiment will be described with reference to these drawings.

  At time T1, the release button 16 of the camera is released. When the release button of the camera is half-pressed at time T2, the control device 20 causes the image sensor 8 to perform an accumulation operation in order to acquire an image used for live view display, photometry, and focus detection. At this time, as shown in FIG. 6A, the focal plane shutter 7 has both the front curtain 7a and the rear curtain 7b in a charged state and an open state, and therefore the aperture 7c is opened.

  At time T3, the charge storage of the image sensor 8 and the readout of the stored charge are completed, and the control device 20 stores the captured image data in the memory 20b and generates an image for live view from the captured image by the image processing circuit 21. The monitor display control circuit 24 updates the image on the monitor (LCD) 9. Further, the control device 20 performs photometric calculation for exposure control at the time of photographing using data of RGB photographing pixels in the image data of the memory 20b. Further, the control device 20 performs focus detection calculation using the data of the focus detection pixel in the image data of the memory 20b, calculates the defocus amount and the lens drive amount of the photographing lens 3, and performs the focusing lens drive control. The apparatus 4 drives the focusing lens of the photographic lens 3 to adjust the focus. Thereafter, these operations are repeated until the release button is fully pressed.

  When the release button is fully pressed at time T4, the photographing operation is started. First, the control device 20 drives the main mirror 6 to the position 6a indicated by the broken line in FIG. 1 by the main mirror driving device 17, and retracts it from the photographing optical path. The control device 20 narrows down the aperture 5 to the aperture value of the photometric calculation result calculated immediately before the release button is fully pressed by the aperture drive control device 23.

  At time T5, the control device 20 causes the shutter drive control device 22 to return the front curtain 7a of the focal plane shutter 7. FIG. 6B shows a state in which the front curtain 7a is restored and the aperture 7c is closed.

  At time T6, the control device 20 causes the image sensor 8 to start an accumulation operation for imaging, and the shutter drive control device 22 causes the front curtain 7a of the focal plane shutter 7 to travel and opens the aperture 7c. At time T7 when the shutter time of the photometric calculation result has elapsed, the control device 20 causes the shutter drive control device 22 to travel the rear curtain 7b of the focal plane shutter 7 and closes the aperture 7c. FIG. 6C shows a state in which the rear curtain 7b starts to close the aperture 7c.

  At time T8, the travel of the rear curtain 7b of the focal plane shutter 7 is completed, and the aperture 7c is closed. FIG. 6D shows a state where the rear curtain 7b is closed and the aperture 7c is shielded from light. The control device 20 ends the accumulation operation of the image sensor 8, reads the captured image data from the image sensor 8, performs various processes on the captured image by the image processing circuit 21, and records the captured image in the image recording unit 25. The shutter drive controller 22 charges the spring of the front curtain 7a and the spring of the rear curtain 7b of the focal plane shutter 7. At this time, the front curtain 7a is kept open without moving, the rear curtain 7b is opened, and the aperture 7c is opened. Further, the control device 20 opens the diaphragm 5 by the diaphragm drive control device 23.

  When charging of the spring of the front curtain 7a and the spring of the rear curtain 7b is completed at time T9, the focal plane shutter 7 returns to the open state as shown in FIG. The control device 20 repeatedly performs the above-described imaging, reading of image data, image processing, updating of a monitor image for live view, photometry calculation, and focus detection calculation until a predetermined time elapses.

  According to the embodiment described above, the following operational effects can be obtained. First, the digital camera of one embodiment changes the positions of the photometric sensor on the optical finder side like the conventional digital camera described above, the focus detection optical system and the AF sensor at the bottom of the camera body, and the main mirror and sub mirror in a complicated manner. The mirror drive mechanism is not required, the structure and mechanism are simplified, and the camera can be miniaturized. In one embodiment, live view display, photometry, and focus detection can be performed using a captured image of the image sensor 8 while the main mirror 6 is set in the photographing optical path except during photographing, and an optical viewfinder is used. A viewfinder image can also be visually recognized.

  Note that the timing for outputting the live view image signal, the timing for outputting the AE image signal, and the timing for outputting the AF focus detection signal may be the same or different. For example, when control using both the AE result and the AF result is performed (for example, when a subject is tracked using the AE result and the AF result), the timing for outputting the image signal for AE and the focus for AF It may be preferable to match the timing of outputting the detection signal.

  Further, the live view image signal and the AE image signal may be the same, but the thinning amount, the output timing, and the like may be different. The pixels used for outputting the live view image signal may be different from the pixels used for outputting the AE image signal.

  In addition, when the RGB imaging pixel 310 outputs an image signal, the image signal output from the focus detection pixels 313 and 314 has different sensitivity and spectral characteristics compared to the RGB imaging pixel. Not suitable for use. Therefore, the interpolation processing may be performed using the RGB imaging pixels 310 arranged around the focus detection pixels 313 and 314.

  The metering method (for example, center-weighted metering, spot metering, etc.) can be specified by the user via the setting button 16 that can instruct various settings provided in the camera body 1, or can be changed according to the shooting mode. It is. In this case, the RGB imaging pixel 310 that outputs the AE image signal of the imaging element 8 differs depending on the photometry method, and when the focus detection pixels 313 and 314 are included in the photometric range, the focus detection pixel. It is preferable to perform the photometric calculation without using the signals 313 and 314. Further, interpolation processing may be performed using surrounding RGB imaging pixels 310.

  Furthermore, the charge accumulation times of the RGB imaging pixel 310 and the focus detection pixels 313 and 314 may be the same or different.

  A plurality of focus detection pixels 313 and 314 are arranged in a line. It is preferable that the pixel group configured by arranging a plurality of focus detection pixels 313 and 314 is scattered on the same plane of the image sensor. The main mirror 6 and the focal plane shutter 7 can be omitted. Further, the penta roof prism 12 or the like may be omitted, and a so-called electronic viewfinder may be employed.

Cross-sectional view of digital camera of one embodiment The figure which shows the electrical constitution of the digital camera of one embodiment Partial front view of image sensor Layout of focus detection area on the shooting screen Time chart showing operation of digital camera of one embodiment The figure which shows operation | movement of the focal plane shutter of one embodiment.

Explanation of symbols

3; Photography lens, 6; Main mirror, 6a; Retraction position of the main mirror from the photographing optical path, 7; Focal plane shutter, 7a; Front curtain, 7b; Rear curtain, 8; Image sensor, 9; Monitor, 11-14 Optical finder

Claims (7)

An image sensor having a first pixel that outputs a signal used for focus detection based on light through the photographing lens, and a second pixel that outputs an image signal based on the light through the photographing lens;
A first position set in the optical path from the photographic lens to the image sensor and a second position set in a position retracted from the optical path are freely movable, and when positioned at the first position, An optical path dividing means for dividing light through the taking lens into reflected light and transmitted light;
And a control unit that performs photometry based on the image signal and performs focus detection based on a signal used for focus detection when the optical path dividing unit is located at the first position. . The camera of claim 1,
Comprising display means capable of displaying an image based on the image signal;
The camera, wherein the control means displays the image by the display means when the optical path dividing means is located at the first position. An imaging device having a first pixel that outputs a signal used for focus detection by a phase difference detection method based on light through the photographing lens, and a second pixel that outputs an image signal based on the light through the photographing lens When,
Control means for performing focus detection based on a signal used for the focus detection and performing photometry based on the image signal;
A camera comprising: display means for displaying an image based on the image signal. The camera according to any one of claims 1 to 3,
In the imaging device, the first pixel and the second pixel are arranged in a substantially same screen. In the camera according to any one of claims 1 to 4,
The imaging device has a first pixel group configured by arranging a plurality of the first pixels,
The camera, wherein the control means performs the photometry based on the image signal from the second pixel arranged around the first pixel group. In the camera according to any one of claims 1 to 5,
Having designation means for designating a range for performing the photometry in the image sensor;
When the first pixel is included in the range designated by the designation unit, the control unit performs the photometry based on the image signal from the second pixel arranged around the first pixel. A camera characterized by doing. In the camera according to any one of claims 1 to 6,
A shutter member that is disposed between the imaging element and the photographic lens and includes an opening that transmits a light beam from the photographic lens; and a spring member that opens and closes the opening;
The camera is characterized in that when the shutter member performs at least one of the photometry and the focus detection, the spring member has been charged and the opening is opened.

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