JP2004120391A - Solid-state image pickup device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a solid-state image pickup device that picks up both the moving and still images of a subject to pick up the moving image at a desired frame rate and the still image with high resolution without increasing the size and complexity of the device. <P>SOLUTION: In this solid-state image pickup device, one pixel 5 in a photoelectric conversion section 16 is constituted of a solid-state image pickup element 51 for moving image and another image pickup element 52 for still image. This device picks up the moving image of the object with the image pickup element 51 and the still image of the object with the image pickup element 52. At the time of picking up the moving and still images of the object, the device controls the image pickup elements 51 and 52 so that the exposure time of the element 52 may become longer than that of the element 51. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a solid-state imaging device that photoelectrically converts an optical image of a subject and obtains an image signal based on the optical image, and more particularly to a solid-state imaging device that captures both a still image and a moving image of a subject.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a digital camera that obtains an image signal by photoelectrically converting an optical image of a subject by a photoelectric conversion unit in which a large number of solid-state image sensors such as a CCD are arranged in a two-dimensional manner, and records the image signal on a predetermined recording medium Are widely used.
[0003]
In the digital camera as described above, for example, when a still image of a subject is captured, a moving image of the subject is displayed on the monitor, and the monitor may be used as a viewfinder. The operator can confirm a final image while viewing the moving image, and can capture a desired still image. A digital video camera mainly shoots a moving image of a subject, but there are cases where it is desired to shoot a still image even during moving image shooting. In view of the above, in recent years, digital cameras that can shoot both moving images and still images of a subject have become widespread.
[0004]
Here, as a method of obtaining both a moving image and a still image as described above, for example, there is a method of capturing a moving image by one photoelectric conversion unit and recording one of the images captured for the moving image as a still image. is there. However, since a high frame rate is required for moving image capturing, the exposure time of each still image must be relatively short, whereas a high resolution is required for still image capturing. It is necessary to capture images with a long exposure time, and with the above method, the exposure times for moving image capturing and still image capturing cannot be different as described above. Therefore, it is difficult to capture a moving image at a desired frame rate and obtain a high-resolution still image.
[0005]
Therefore, in Patent Document 1, in order to capture a moving image and obtain a high-resolution still image, a photoelectric conversion unit for moving image and a photoelectric conversion unit for still image are separately provided and the optical path is divided by a mirror or the like. Methods for capturing moving images and still images have been proposed.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-201288
[Problems to be solved by the invention]
However, if the optical path is divided by a mirror or the like as described above, the amount of light incident on each solid-state image sensor is reduced, resulting in degradation of image quality for both moving images and still images. In addition, if the optical path is divided, the optical system becomes complicated and it is difficult to reduce the size.
[0008]
In view of the above-described circumstances, the present invention captures a moving image at a desired frame rate without increasing the size and complexity of the solid-state imaging device that captures both a still image and a moving image of a subject. An object of the present invention is to provide a solid-state imaging device capable of capturing a high-resolution still image.
[0009]
[Means for Solving the Problems]
The solid-state imaging device of the present invention has a photoelectric conversion unit in which a large number of solid-state imaging elements that photoelectrically convert an optical image of a subject are two-dimensionally arranged, and an imaging unit that captures an optical image by the photoelectric conversion unit. In the solid-state imaging device including the imaging control unit that controls the imaging unit so as to capture still images and moving images of the subject by the imaging unit, the photoelectric conversion unit has a plurality of solid-state imaging elements for one pixel. A part of the plurality of solid-state image pickup devices is used as a still image solid-state image pickup device, and the other solid-state image pickup device is used as a moving image solid-state image pickup device. The solid-state image pickup device controls the solid-state image pickup device so that the solid-state image pickup device picks up a still image and the moving image solid-state image pickup device picks up a moving image.
[0010]
Here, “having a plurality of solid-state imaging devices for one pixel” means that a plurality of light receiving units are included in one pixel, and signal charges received and photoelectrically converted by each light receiving unit are selected. Means that it can be read out automatically.
[0011]
Further, the imaging control means may control the still image solid-state imaging device and the moving image solid-state imaging device under different imaging conditions.
[0012]
Here, the “imaging condition” means, for example, the exposure time of the solid-state imaging device, the number of the solid-state imaging devices to be operated during imaging.
[0013]
Further, the imaging control means may control the solid-state image sensor so that the exposure time of the still image solid-state image sensor is longer than the exposure time of the moving image solid-state image sensor.
[0014]
Further, the area of the light receiving portion of the moving image solid-state imaging device can be made larger than the area of the light receiving portion of the still image solid-state imaging device.
[0015]
【The invention's effect】
According to the solid-state imaging device of the present invention, a plurality of solid-state imaging devices are provided for one pixel, and some of the plurality of solid-state imaging devices are used as still-image solid-state imaging devices. Since the solid-state imaging device is configured to be a moving image solid-state imaging device, the still image is captured by the still image solid-state imaging device, and the moving image is captured by the moving image solid-state imaging device. By controlling the solid-state image sensor so that the exposure time of the solid-state image sensor for still images is longer than the exposure time of the solid-state image sensor, moving images are captured at a desired frame rate and high-resolution still images are captured. Imaging can be performed.
[0016]
Further, unlike the invention described in Patent Document 1, it is not necessary to provide a mirror or the like to divide the optical path for moving image capturing and still image capturing, so that the size of the apparatus can be reduced.
[0017]
In addition, when the area of the light receiving portion of the moving image solid-state imaging device is made larger than the area of the light receiving portion of the still image solid-state imaging device, it is possible to increase the amount of light received during moving image pickup. A decrease in frame rate and resolution can be suppressed.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a solid-state imaging device of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a digital video camera 10 to which the solid-state imaging device of the present embodiment is applied.
[0019]
As shown in FIG. 1, the digital video camera 10 captures an optical image of a subject and outputs an image signal based on the optical image. After performing the signal processing, the preprocessing unit 18 that outputs the digital data after being digitized by an A / D converter (not shown), and the signal processing unit that performs predetermined image processing on the digital data output from the preprocessing unit 18 20, a monitor 22 that displays a visible image based on processed data subjected to predetermined image processing in the signal processing unit 20, an operation unit 24 that selects a still image shooting mode and a moving image shooting mode, and an operation of the entire camera And control means 26 for controlling the above.
[0020]
The imaging unit 11 includes an optical lens system 12 that forms an optical image of a subject, a mechanical shutter 14 that controls the incidence of an optical image formed by the optical lens system 12 on a photoelectric conversion unit 16 (to be described later), and an optical lens system 12. Is provided with a photoelectric conversion unit 16 that photoelectrically converts the optical image formed by the above and outputs an image signal.
[0021]
As shown in FIG. 2, the photoelectric conversion unit 16 receives signal charges from the light receiving area 1, the vertical transfer CCD driving circuit 2 that controls the vertical transfer CCD 6 in the light receiving area 1, and the vertical transfer CCD 6, and in the horizontal direction X, receives the signal charges. Are provided, and a horizontal charge transfer path 3 for transferring the signal and an output amplifier 4 for amplifying the signal charge output from the horizontal charge transfer path 3 and outputting it as an image signal.
[0022]
The light receiving region 1 is provided with a pixel 5 that receives an optical image formed by the optical system lens 12 and a vertical transfer CCD 6 that reads the signal charges photoelectrically converted and transfers them in the vertical direction Y. ing. As shown in FIG. 2, in the light receiving region 1, the pixels 5 are arranged every other column in each row and every other row in each column to form a so-called honeycomb structure, and the horizontal arrangement of the pixels is 1 It is arranged at a position shifted by 1/2 pitch every other row. Then, the electric charges from each pixel 5 are read out to the vertical transfer CCD 6 arranged close to the right side of each pixel 5 and transferred in the vertical direction Y.
[0023]
As shown in FIG. 3, the pixel 5 is provided with two photodiode regions 5a and 5b, and a moving image solid-state image pickup device 51 having the photodiode region 5a and a still image solid-state image pickup having the photodiode region 5b. An element 52 is included. The photodiode region 5a has a relatively large area and constitutes a main photosensitive portion. The photodiode 5b has a relatively small area and constitutes a secondary photosensitive portion. Also, transfer electrodes (not shown) for reading the signal charges photoelectrically converted by the moving image solid-state image sensor 51 and the still image solid-state image sensor 52 to the vertical transfer CCD 6 are provided for each solid-state image sensor. Thus, the signal charges can be selectively read out from the moving image solid-state image pickup device 51 or the still image solid-state image pickup device 52 to the vertical transfer CCD 6.
[0024]
The operation unit 24 includes a mode selection unit 24a and a release shutter button 24b. The mode selection unit 24a outputs a mode signal corresponding to the mode selected by the operator between the still image shooting mode and the moving image shooting mode to the control means 26. The release shutter button 24b is a button having a stroke in two stages. The first stage stroke (hereinafter referred to as half-pressed state) sets the digital video camera 10 to a still image capturing preparation stage, and the second stage stroke (hereinafter referred to as a half-stroke stroke). A trigger signal for actually capturing a still image in a fully-pressed state).
[0025]
The control means 26 is a microcomputer or CPU that controls the operation of the entire digital video camera 10. The control unit 26 includes an imaging control unit 27. The imaging control unit 27 sets the entire digital video camera 10 to the still image shooting mode or the moving image shooting mode in accordance with the input mode signal.
[0026]
Next, the operation when a moving image is captured and recorded by the digital video camera 10 of the above embodiment will be described with reference to the flowchart shown in FIG.
[0027]
First, the imaging of the moving image is started when the operator selects the moving image shooting mode by the mode selection unit 24a, and is in a standby state until it is selected (S10). When the moving image shooting mode is selected in the mode selection unit 24a, a moving image mode signal corresponding to the moving image shooting mode is output from the mode selection unit 24a to the control unit 26. The imaging control unit 27 in the control unit 26 controls the lens optical system 12, the shutter 14, and the photoelectric conversion unit 16 in the imaging unit 11 based on predetermined moving image shooting conditions set in advance according to the moving image mode signal. . At this time, the exposure time in the photoelectric conversion unit 16 is set to be shorter than the exposure time at the time of still image shooting described later. Then, only the moving image solid-state imaging device 51 in the photoelectric conversion unit 16 is driven by the imaging control means 27 (S12), and exposure is started (S14). The exposure is performed for a preset exposure time (S16), but the exposure time may be controlled by the shutter 14 or a so-called electronic shutter. Then, after a predetermined exposure time has elapsed, the transfer electrode and the vertical transfer CCD 6 are driven by the vertical transfer CCD drive circuit 2, and the signal charges accumulated in the moving image solid-state imaging device 51 are transferred to the vertical transfer CCD 6. The signal charges transferred to the vertical transfer CCD 6 are sequentially transferred to the horizontal charge transfer path 3 for each row, and the signal charges transferred to the horizontal charge transfer path 3 are sequentially transferred in the horizontal direction X direction to output the amplifier 4 Is multiplied by a predetermined gain and read out as a moving image signal (S18). The moving image signal output from the photoelectric conversion unit 16 as described above is A / D converted by the preprocessing unit 18 and output to the signal processing unit 20 as moving image digital data. The signal processing unit 20 performs predetermined image signal processing. (S20), it is recorded in the memory in the signal processing unit 20 (S22). The processes from S14 to S22 are repeated until an instruction signal for ending the moving image shooting from the operator is input, and the processed moving image data recorded in the memory is output to the monitor 22 for each frame. 22 displays a moving image.
[0028]
Next, the operation when still image shooting is performed while moving images are being captured by the digital video camera 10 as described above will be described with reference to the flowchart shown in FIG.
[0029]
First, recording of a still image is started by the operator selecting a still image shooting mode with the mode selection unit 24a, and is in a standby state until it is selected (S30). When the still image shooting mode is selected in the mode selection unit 24a, a still image mode signal corresponding to the still image shooting mode is output from the mode selection unit 24a to the control unit 26. At this time, the control means 26 confirms whether or not the release shutter button 24b in the operation unit 24 has been half-pressed (S32). When the release shutter button 24b is pressed halfway in S32, the imaging control means 27 in the control means 26, the lens optical system 12 in the imaging means 11 and the shutter based on predetermined still image shooting conditions set in advance. 14 and the photoelectric conversion unit 16 are controlled. At this time, the exposure time in the photoelectric conversion unit 16 is set to be longer than the exposure time in moving image shooting. When the release shutter button 24b is fully pressed, the still image solid-state image pickup device 52 is driven by the image pickup control means 27 together with the moving image solid-state image pickup device 51 in the photoelectric conversion unit 16 (S34). Is started (S36). In S32, if the release button 24b is not pressed halfway within a predetermined time, the still image shooting mode is terminated and the movie shooting mode is restored. The exposure is performed for a preset exposure time. After a predetermined exposure time has elapsed (S38), the transfer electrode and the vertical transfer CCD 6 are driven by the vertical transfer CCD drive circuit 2 and stored in the still image solid-state image pickup device 52. The signal charges thus transferred are transferred to the vertical transfer CCD 6. The signal charges transferred to the vertical transfer CCD 6 are sequentially transferred to the horizontal charge transfer path 3 for each row, and the signal charges transferred to the horizontal charge transfer path 3 are sequentially transferred in the horizontal direction X direction to output the amplifier 4 Is multiplied by a predetermined gain and read out as a still image signal (S40). The still image signal output from the photoelectric conversion unit 16 as described above is A / D converted by the preprocessing unit 18 and output to the signal processing unit 20 as still image digital data, and a predetermined image is output from the signal processing unit 20. After the signal processing is performed (S42), it is recorded in the memory in the signal processing unit 20 (S44). When signal charges are read in the moving image shooting mode (S18 in FIG. 4) when the signal charges are read in S40, the still image shooting mode is completed after the transfer in the moving image shooting mode is completed. It is assumed that the signal charges are read out.
[0030]
According to the digital video camera 10 of the present embodiment, the photoelectric conversion unit 16 includes the moving image solid-state image pickup device 51 and the still image solid-state image pickup device 52 for one pixel. The moving image is picked up by the still image solid-state image pickup device 52, so that the exposure of the still image solid-state image pickup device 52 is longer than the exposure time of the moving image solid-state image pickup device 51 as described above. By controlling the solid-state imaging device so that the time becomes longer, it is possible to capture a moving image at a desired frame rate and to capture a high-resolution still image.
[0031]
In the above-described embodiment, the signal charge accumulated in the moving image solid-state image sensor 51 and the signal charge accumulated in the still image solid-state image sensor 52 are transferred to the same vertical transfer CCD 6 at different timings. However, the vertical transfer CCD for the moving image solid-state image pickup device and the vertical transfer CCD for the still image solid-state image pickup device are separately provided, and the signal charge accumulated in the moving image solid-state image pickup device 51 and the still image solid-state image pickup device 52 are provided. Both of the signal charges stored in the memory may be transferred simultaneously. In this case, however, the transfer to the horizontal charge transfer path must be performed at different timings, or a horizontal charge transfer path output amplifier must be provided separately.
[0032]
In the embodiment, the solid-state image sensor 51 is controlled such that the number of moving image solid-state image sensors 51 operated during moving image imaging is smaller than the number of still image solid-state image sensors 51 operated during still image imaging. It may be.
[0033]
Further, in the above embodiment, when reading the signal charges accumulated in the moving image solid-state imaging device 51 during moving image capturing, pixels may be thinned out at a predetermined rate.
[0034]
Further, in the above embodiment, signal charges may be read out in multiple times instead of once when still images are captured.
[0035]
In the above-described embodiment, the photoelectric conversion unit 16 is configured by a CCD solid-state imaging device. However, the photoelectric conversion unit 16 is not limited thereto, and is configured by a MOS-type solid-state imaging device including a photodiode region and a MOS transistor. It may be.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of a digital video camera to which a solid-state imaging device of the present invention is applied. FIG. 2 is a diagram showing details of a photoelectric conversion unit in the digital video camera shown in FIG. FIG. 4 is a flowchart for explaining the operation of the digital video camera shown in FIG. 1 when capturing a moving image. FIG. 5 is a flowchart illustrating the operation of the digital video camera shown in FIG. Flow chart explaining symbols [Explanation of symbols]
1 Photosensitive area 2 Vertical transfer CCD drive circuit 3 Horizontal charge transfer path 4 Output amplifier 5 Pixel 6 Vertical transfer CCD
DESCRIPTION OF SYMBOLS 10 Digital video camera 11 Imaging means 12 Optical system lens 14 Shutter 16 Photoelectric conversion part 18 Preprocessing part 20 Signal processing part 22 Monitor 24 Operation part 24a Mode selection part 24b Release shutter button 51 Solid-state image sensor 52 for moving images Solid-state imaging for still images element

Claims (4)

An imaging unit having a photoelectric conversion unit in which a large number of solid-state imaging elements that photoelectrically convert an optical image of a subject are arranged in a two-dimensional manner, and imaging the optical image by the photoelectric conversion unit, and the subject by the imaging unit In a solid-state imaging device comprising: an imaging control unit that controls the imaging unit to capture a still image and a moving image of
The photoelectric conversion unit has a plurality of solid-state imaging devices for one pixel,
A part of the plurality of solid-state image sensors is configured as a still image solid-state image sensor, and the other solid-state image sensor is configured as a moving image solid-state image sensor.
The solid-state imaging characterized in that the imaging control means controls the solid-state imaging device so that the solid-state imaging device for still image captures a still image and the solid-state imaging device for moving image captures a moving image. apparatus. 2. The solid-state imaging device according to claim 1, wherein the imaging control means controls the still image solid-state imaging device and the moving image solid-state imaging device under different imaging conditions. The imaging control means controls the solid-state image sensor so that an exposure time of the still image solid-state image sensor is longer than an exposure time of the moving image solid-state image sensor. 2. The solid-state imaging device according to 2. 4. The solid-state imaging device according to claim 1, wherein an area of a light receiving portion of the moving image solid-state imaging element is larger than an area of a light receiving portion of the still image solid-state imaging element.

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