JP2009031562A - Light receiving element, light receiver, focus detecting device, camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain output suitable for each use from one light receiving element when using the light receiving element in a plurality of uses. <P>SOLUTION: The light receiving element for arranging a plurality of photoelectric conversion parts accumulating charges in response to a light receiving amount includes: a vertical transfer circuit 163 and a horizontal transfer circuit 162 for adding the charge of the plurality of the photoelectric conversion parts; and an addition range setting part 164 for setting the range of the photoelectric conversion part adding the charge by the vertical transfer circuit 163 and the horizontal transfer circuit 162. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light receiving element, a light receiving device including the light receiving element, a focus detection device, and a camera.

  2. Description of the Related Art Conventionally, a digital camera that captures a subject image using a light receiving element (area sensor) in which a plurality of pixels are arranged in a two-dimensional manner is known. In such a digital camera, in order to obtain a signal charge with sufficient contrast even from a low-luminance subject, the signal charge obtained by the area sensor is added and not added in the vertical and horizontal directions, respectively, according to the brightness. A technique for switching is known (see Patent Document 1).

JP-A-10-126682

  The light receiving element as described above performs various uses other than the photographing of the subject image, for example, performs AE (Automatic Exposure) processing based on the brightness of the subject image detected by the light receiving element, and uses the same light receiving element. No consideration has been given to control when performing AF (Automatic Focus) processing based on the focus adjustment state of the photographic lens detected in this way.

The light-receiving element according to the first aspect of the present invention is a light-receiving element in which a plurality of photoelectric conversion units for accumulating charges corresponding to the amount of received light are arranged, and an addition unit that adds the charges of the plurality of photoelectric conversion units, and an addition unit And an addition range setting means for setting a range of the photoelectric conversion unit to which charges are added.
According to a second aspect of the present invention, a light receiving device includes the light receiving element according to the first aspect and output means capable of outputting the added electric charges corresponding to different ranges.
According to a third aspect of the present invention, there is provided a focus detection device according to the first aspect, the focus detection optical system that guides light through the imaging optical system to the light reception element, and the charge added by the adding means. Focus detection means for detecting the focus adjustment state of the imaging optical system based on the signal.
According to a fourth aspect of the present invention, in the focus detection apparatus according to the third aspect, the plurality of photoelectric conversion units have different spectral sensitivity characteristics, and the adding means has the same spectral sensitivity characteristic among the photoelectric conversion units within the range. The apparatus further includes a second addition unit that adds the charges of the photoelectric conversion unit and adds the charges added by the addition unit to the photoelectric conversion units having different spectral sensitivity characteristics, and the focus detection unit adds the charges by the second addition unit. The focus adjustment state is detected based on a signal corresponding to the generated charge.
According to a fifth aspect of the present invention, in the focus detection apparatus according to the third or fourth aspect, the addition range setting means corresponds to a focus detection region set in the screen by the imaging optical system among the plurality of photoelectric conversion units. The range of the photoelectric conversion unit to be set is set.
According to a sixth aspect of the present invention, in the focus detection apparatus according to the fifth aspect, the position of the focus detection area in the screen can be changed, and the addition range setting means sets the range according to the change of the position of the focus detection area. To change.
According to a seventh aspect of the present invention, in the focus detection apparatus according to any one of the third to sixth aspects, the addition range setting means sets the range according to the focal length of the imaging optical system.
According to an eighth aspect of the present invention, there is provided a camera comprising: the light receiving element according to the first aspect; and a control unit capable of executing a plurality of different controls based on the charge. The range is set according to the type of control executed by the means.
According to a ninth aspect of the present invention, there is provided a camera comprising: the light receiving element according to the first aspect; and an imaging optical system that forms an image of a light beam on the light receiving element. The range is set according to the focal length.
According to a tenth aspect of the present invention, in the camera according to the eighth aspect, an imaging optical system for forming an image of a light beam on the light receiving element is provided, and the control means performs image discrimination processing and exposure calculation by the imaging optical system. Control of at least one of the processing and focus detection control of the imaging optical system are performed.
According to an eleventh aspect of the present invention, in the camera according to the tenth aspect, when the control means controls the discrimination process or the exposure calculation process, the plurality of photoelectric conversion units set a substantially square range. In addition, when the control means performs focus detection control, a rectangular range is set.
According to a twelfth aspect of the present invention, in the camera according to the tenth or eleventh aspect, the plurality of photoelectric conversion units have different spectral sensitivity characteristics, and the addition unit controls the discrimination process or the exposure calculation process. Is to add charges of photoelectric conversion units having the same spectral sensitivity characteristics.
A thirteenth aspect of the present invention is the camera according to any one of the eighth to twelfth aspects, further comprising luminance detection means for detecting the luminance of incident light, wherein the addition range setting means is detected by the luminance detection means. The range is set according to the brightness.
According to a fourteenth aspect of the present invention, in the camera according to any one of the ninth to thirteenth aspects, the addition range setting means sets the range according to the photographing distance by the imaging optical system.
According to a fifteenth aspect of the present invention, in the camera according to any one of the tenth to fourteenth aspects, the addition range setting means sets the range according to the focal length of the imaging optical system.
According to a sixteenth aspect of the present invention, there is provided a camera comprising: a light receiving element in which a plurality of photoelectric conversion units that store charges according to light incident through an imaging optical system are arranged; and an addition that adds the charges of the plurality of photoelectric conversion units. Means for detecting the first state of the image by the imaging optical system based on the charge and a second state different from the first state, and the adding means adds according to the state detected by the detecting means Addition range setting means for setting the range of the photoelectric conversion unit.

  According to the present invention, when one light receiving element is used for a plurality of applications, an output suitable for each application can be obtained from the light receiving element.

  FIG. 1 is a configuration diagram of a camera according to an embodiment of the present invention. The camera shown in FIG. 1 includes a lens unit 100 and a camera body 200. The lens unit 100 includes a photographing lens 1, a diaphragm 2, a drive mechanism 3, and a lens data unit 4. The camera body 200 includes a focus detection device 5, a pentaprism 6, a signal processing unit 7, a drive motor 8, a microcomputer 9, a shutter 11, an image sensor 12, a main mirror 13, a sub mirror 14, an eyepiece 15, an area sensor 16, and a rear monitor. 18 and a viewfinder screen 19.

  The photographing lens 1 is an imaging optical system for forming a subject image, and is constituted by a plurality of lenses. The light incident on the camera body 200 via the photographing lens 1 is partially reflected by the main mirror 13 and forms a subject image on a finder screen 19 provided at a position optically equivalent to the image sensor 12. . The subject image formed on the finder screen 19 is guided from the pentaprism 6 to the eyepiece lens 15. The photographer can confirm the composition before photographing by looking through the eyepiece 15 and visually recognizing the subject image.

  Of the light incident on the camera body 200 via the photographing lens 1, the light transmitted through the main mirror 13 is reflected by the sub mirror 14 and input to the focus detection device 5. The focus detection device 5 is a device for detecting the focus adjustment state of the photographing lens 1 by a known phase difference detection method using pupil division, and has an area sensor 16 and a focus detection optical system. The focus detection optical system guides light through the photographing lens 1 to the area sensor 16.

  In the area sensor 16, a plurality of photoelectric conversion units (pixels) that accumulate electric charges according to the amount of received light are two-dimensionally arranged. The charge accumulated by each pixel is added for each range set as will be described later, and a light reception signal is output from the area sensor 16 according to the addition result. Based on the light reception signal output from the area sensor 16 in this way, the microcomputer 9 detects a defocus amount indicating the focus adjustment state of the photographing lens 1. The area sensor 16 may be a CMOS (Complementary Metal Oxide Semiconductor) type light receiving element, a CCD (Charge Coupled Device), or the like. The light reception signal output from the area sensor 16 is also input to the microcomputer 9.

  The microcomputer 9 performs various controls based on the light reception signal output from the area sensor 16. For example, the microcomputer 9 performs AF processing for calculating the defocus amount and adjusting the focus of the photographing lens 1. Further, based on the light reception signal from the area sensor 16, main microcomputer determination processing, that is, image determination processing by the photographing lens 1, exposure calculation processing for calculating appropriate exposure, and the like are executed by the microcomputer 9.

  The drive mechanism 3 is a mechanism for driving a focus adjustment lens and a zoom lens included in the photographing lens 1, and is connected to the drive motor 8 through the coupling unit 10. When the microcomputer 9 outputs a drive command to the drive motor 8, the drive motor 8 is driven according to the drive command, and the generated drive force is transmitted to the drive mechanism 3. As a result, the focus adjustment lens and the zoom lens are driven by the drive mechanism 3, and the focus adjustment and the focal length adjustment of the photographing lens 1 are performed. The drive motor 8 may be built in the lens unit 100 instead of the camera body 200.

  The lens data unit 4 is connected to the microcomputer 9 via the coupling unit 10. The lens data unit 4 detects the adjustment state of the focal length of the photographing lens 1 and outputs focal length information to the microcomputer 9. When the lens unit 100 is not a zoom lens, that is, when the focal length of the photographing lens 1 is fixed, the focal length may be stored in the lens data unit 4 in advance. The shutter 11 controls the exposure time at the time of shooting according to the shutter speed set according to the appropriate exposure obtained by the exposure calculation process performed by the microcomputer 9.

  When a release button (not shown) in the camera body 200 is pressed halfway by the photographer, the defocus amount is detected by the microcomputer 9 based on the output of the light beam image formed on the area sensor 16 by the photographing lens 1. Is done. Then, based on the detected defocus amount, the microcomputer 9 gives a drive instruction to the drive motor 8 to adjust the focus of the photographing lens 1. Thereafter, when the release button is fully pressed by the photographer, photographing is performed.

  FIG. 2 shows how the camera operates during shooting. As shown in FIG. 2, at the time of photographing, the main mirror 13 and the sub mirror 14 are retracted from the optical path of the photographing lens 1, and the image pickup device 12 is exposed by opening the shutter 11 only for the set shutter speed. At this time, an image of a light beam is formed on the image sensor 12 by the photographing lens 1. Similar to the area sensor 16, the image sensor 12 is a light receiving element in which a plurality of photoelectric conversion units (pixels) are two-dimensionally arranged, accumulates charges corresponding to the amount of received light for each pixel, and performs signal processing. A light reception signal is output to 7.

  The signal processing unit 7 converts the received light signal into image data by performing analog-digital conversion processing on the received light signal output from the image sensor 12. Further, after performing predetermined image processing as required, image data is output to the microcomputer 9. The microcomputer 9 displays an image based on the image data output from the signal processing unit 7 on the rear monitor 18 and records the image data on a recording medium (not shown). As described above, the image of the subject is photographed by recording the image data based on the light from the subject obtained in the image sensor 12 on the recording medium. After shooting, the main mirror 13 and the sub mirror 14 are returned to their original positions and the shutter 11 is closed to return to the state shown in FIG.

  When a predetermined mode called a live view mode is set in the camera body 200, image data based on light from the subject is continuously acquired while maintaining the state shown in FIG. The moving image of the subject may be displayed on the rear monitor 18. The moving image of the subject displayed on the rear monitor 18 at this time is called a through image. When the release button is pressed halfway during the through image display, the microcomputer 9 executes AF processing based on the image signal from the image sensor 12. This AF process is performed by a known contrast detection method without using the defocus amount detected by the focus detection device 5. Alternatively, by returning the main mirror 13 and the sub mirror 14 to the positions shown in FIG. 1, the light from the subject is guided to the focus detection device 5 and the defocus amount is calculated by the microcomputer 9 based on the output signal from the area sensor 16. Alternatively, phase difference detection AF processing may be performed.

  Alternatively, in the image pickup device 12, focus detection pixels for performing pupil division type phase difference detection are mixed, and light beams from a partial region of the exit pupil of the photographing lens 1 are received using the focus detection pixels. The AF process may be performed by the microcomputer 9 by detecting the defocus amount. In such a case, the phase difference detection AF process can be performed even in the mirror-up state as shown in FIG.

  As described above, when the release button is half-pressed, the microcomputer 9 can perform the AF process using the area sensor 16. Furthermore, the main sensor discrimination process and the exposure calculation process can also be performed using the area sensor 16. That is, in the state of FIG. 1, the microcomputer 9 performs AF processing, main subject determination processing, exposure calculation processing, and the like based on the charges added for each range set for the area sensor 16. On the other hand, when the live view mode is set, the microcomputer 9 performs AF processing, main subject discrimination processing, and exposure calculation processing using the image sensor 12. That is, in the state of FIG. 2, the microcomputer 9 executes AF processing, main subject determination processing, exposure calculation processing, and the like based on the charge added for each range set by the image sensor 12.

  Next, the configuration of the area sensor 16 will be described. FIG. 3 is a schematic configuration diagram of the area sensor 16 using a CCD type two-dimensional image sensor. The area sensor 16 includes a sensor array unit 161, a horizontal transfer circuit 162, a vertical transfer circuit 163, an addition range setting unit 164, and an output circuit 165.

  The sensor array unit 161 is a part that receives light and accumulates charges, and a plurality of pixels are arranged two-dimensionally as described above. Charges corresponding to the amount of received light within a predetermined accumulation time are accumulated by each pixel of the sensor array unit 161. The vertical transfer circuit 163 is a circuit for reading the amount of charge accumulated in each pixel of the sensor array unit 161, that is, the amount of accumulated charge, and adding the charges of the pixels in the range set by the addition range setting unit 14. is there. The horizontal transfer circuit 162 adds the charges transferred from the vertical transfer circuit 163 in accordance with the range set by the addition range setting unit 164 and outputs the result to the output circuit 165.

  The addition range setting unit 164 sets a range in which the charge accumulation amount of the sensor array unit 161 is added to the horizontal transfer circuit 162 and the vertical transfer circuit 163, respectively.

  The output circuit 165 outputs to the microcomputer 9 a light reception signal corresponding to the charge accumulation amount read and added by the horizontal transfer circuit 162 and the vertical transfer circuit 163. That is, among the pixels arrayed two-dimensionally in the sensor array unit 161, the charges accumulated within a predetermined accumulation time are added to a plurality of pixels within the range set by the addition range setting unit 164. . A light reception signal corresponding to the added electric charge is output to the microcomputer 9.

  As described above, the addition range setting unit 164 sets the pixel range of the sensor array unit 161 to which charges are added. In the range thus set, the vertical transfer circuit 163 and the horizontal transfer circuit 162 add the charges of each pixel accumulated within a predetermined accumulation time, and output a light reception signal to the microcomputer 9 via the output circuit 165. At this time, the pixel range set by the addition range setting unit 164 is determined according to an instruction from the microcomputer 9.

  FIG. 4 is a flowchart of an addition mode determination flow showing the contents of processing executed when the microcomputer 9 designates a pixel range to the addition range setting unit 164. In step S10, the microcomputer 9 determines whether or not the application of the area sensor 16 is for AF. If it is for AF, the process proceeds to step S20. If it is not for AF, that is, if the area sensor 16 is used for the main subject discrimination process or exposure calculation process, the process proceeds to step S60.

  In step S <b> 20, the microcomputer 9 acquires luminance information related to the luminance of light incident on the camera body 200. For example, the luminance information is calculated by the microcomputer 9 based on a light reception signal output from the area sensor 16. Further, for example, in the live view mode, the luminance may be calculated based on the light reception signal output from the image sensor 12. Alternatively, a brightness detection sensor may be installed in the camera body 200, and brightness information may be acquired based on a detection signal from the sensor.

  In step S30, the microcomputer 9 determines the number of pixels to be added in the Y direction, that is, the vertical direction, based on the luminance information acquired in step S20. At this time, the pixel addition number is increased as the luminance is lower, and the pixel addition number is decreased as the luminance is higher.

  In step S <b> 40, the microcomputer 9 acquires focal length information of the photographing lens 1. The focal length information is output from the lens data unit 4 as described above.

  In step S50, the microcomputer 9 determines the number of pixels to be added in the X direction, that is, in the horizontal direction, based on the focal length information acquired in step S40. At this time, the smaller the focal length, the smaller the pixel addition number, and the longer the focal length, the larger the pixel addition number. For example, when a wide lens with a short focal length is used as the photographing lens 1 or when the zoom lens is set to the wide side, the pixel addition number is reduced. Conversely, when the zoom lens is set to the tele side, the number of added pixels is increased. If step S50 is performed, it will progress to step S80.

  By executing the processing of steps S20 to S50 described above, a rectangular range is set during AF processing, that is, when the microcomputer 9 performs focus detection control of the photographing lens 1.

  On the other hand, when the process proceeds from step S10 to step S60, in step S60, the microcomputer 9 acquires the focal length information of the photographing lens 1 in the same manner as in step S40.

  In step S70, the microcomputer 9 determines the square pixel addition number based on the focal length information acquired in step S60. That is, the pixel addition numbers in the X direction (horizontal direction) and the Y direction (vertical direction) are determined. At this time, as in step S50, the smaller the focal length, the smaller the pixel addition number, and the longer the focal length, the larger the pixel addition number. If step S70 is performed, it will progress to step S80.

  When the processing of steps S60 and S70 described above is executed, when the microcomputer 9 performs the main subject determination processing or exposure calculation processing, a square range is set. Note that a substantially square range may be set, even if it is not necessarily an exact square shape.

  In step S80, the microcomputer 9 sets a data addition range for each pixel of the sensor array unit 161 in accordance with the addition number determined in steps S30 and S50 or step S70. If step S80 is performed, the microcomputer 9 will complete | finish the flowchart of FIG.

  When the data addition range is set as described above, the microcomputer 9 transmits a signal for instructing the set data addition range to the addition range setting unit 164. In this way, the range of pixels set by the addition range setting unit 164 is designated by the microcomputer 9. Thereby, the addition range setting unit 164 can set the range of pixels to which charges are added according to the type of control executed by the microcomputer 9, the luminance of incident light, the focal length of the photographing lens 1, and the like. .

  Examples of pixel ranges set by the processing described above are shown in FIGS. 5 to 7 are examples of pixel ranges set in the sensor array unit 161 of the area sensor 16 when performing AF processing. 5 shows a pixel range when the luminance is low, FIG. 6 shows a high luminance, and FIG. 7 shows a pixel range when a wide lens with a short focal length is used, both of which are rectangular ranges a1 and a2 surrounded by broken lines. , A3, etc. are set. In this way, by setting a rectangular range during AF processing, it is possible to shorten the charge accumulation time and readout time necessary to obtain an appropriate defocus amount and improve the AF processing resolution. .

  On the other hand, FIGS. 8 to 10 are examples of pixel ranges set in the sensor array unit 161 when the main subject discrimination process or the exposure calculation process is performed. In these figures, square ranges b1, b2, b3, etc. enclosed by broken lines are set. As described above, in the main subject discrimination process or the exposure calculation process, by setting a substantially square range, the horizontal direction, that is, the X direction, and the vertical direction, that is, the Y direction can be processed with the same resolution. .

  5 to 10, each pixel of the sensor array unit 161 has a spectral sensitivity characteristic corresponding to any of R (red), G (green), and B (blue). That is, the sensor array unit 161 is provided with a color filter corresponding to any of R, G, or B for each pixel. By detecting the intensity of the light that has passed through the color filter in each pixel, the light intensity for each color component of the subject image formed by the photographing lens 1 can be detected. Thus, in the sensor array unit 161, each pixel has a different spectral sensitivity characteristic. The pixel arrangement as shown in FIGS. 5 to 10 is called a Bayer arrangement. Other arrangements may be used.

  Comparing the examples of FIG. 5 and FIG. 6, it can be seen that the range a1 to a3 at the time of low luminance is set so that the number of pixels in the Y direction is larger than that at the time of high luminance. That is, when the luminance is low, the number of pixels to which charges are added is increased so that the image brightness necessary for AF processing can be obtained. In this way, by setting the range in which charges are added according to the detected luminance, the dynamic range of the received light signal can be improved.

  Further, comparing the examples of FIGS. 5 and 7, it can be seen that the ranges a1 to a3 are set so that the number of pixels in the X direction is smaller than usual when the focal length is short, that is, when the wide lens is used. That is, when the focal length is short, the pixel width of the line sensor for detecting the phase difference is shortened so that the resolution necessary for the AF processing can be obtained. In addition, the line sensor here represents the row | line | column of the range set with respect to the sensor array part 161 like FIG. In other words, the pixel width of the line sensor is the width in the X-axis direction of the range in which pixels are added in the sensor array unit 161.

  When the focal length is short, the subject image is relatively small in the screen of the photographing lens 1, and therefore the frequency component included in the subject image tends to increase in high frequency components. Therefore, by setting a narrow range in which charges are added according to the focal length of the photographic lens 1 as described above, it is possible to detect a high-frequency component of the subject image.

  Instead of the focal length of the photographing lens 1, a range in which charges are added may be set according to the photographing distance by the photographing lens 1. That is, once the defocus amount is obtained by performing AF processing, the photographing distance from the camera body 200 to the subject can be obtained based on the defocus amount and the focal length of the photographing lens 1. By setting a range in which charges are added according to the shooting distance, more accurate AF processing can be performed. At this time, the focal length of the photographic lens 1 may be further added.

  On the other hand, in FIGS. 8 to 10, it can be seen that square ranges b1 to b3 are set by equalizing the number of pixels in the X direction and the Y direction. The sizes of the square ranges b1 to b3 are changed according to the focal length as described above.

  FIG. 8 shows a state where charges are added within a set range for the R pixel, FIG. 9 for the G pixel, and FIG. 10 for the B pixel. For example, in the range b1, as shown in FIG. 8, charges in a total of four R pixels surrounded by a thick frame are added. Similarly, as shown in FIG. 9, the charges in the eight G pixels are added, and as shown in FIG. 10, the charges in the four B pixels are added. The same applies to the ranges b2, b3, and the like. Note that the G pixel in the column including the R pixel and the G pixel in the column including the B pixel may be individually added.

  As described above, the addition range setting unit 164 sets different ranges for each pixel of the sensor array unit 161 according to the type of control executed by the microcomputer 9. In other words, the addition range setting unit 164 sets a range in which a plurality of pixels have a substantially square shape when the microcomputer 9 controls the main subject discrimination process or the exposure calculation process, and the microcomputer 9 performs the AF process. Set a rectangular range. At this time, the microcomputer 9 may execute only one of the main subject determination process and the exposure calculation process.

  The vertical transfer circuit 163 and the horizontal transfer circuit 162 also charge the pixels within the square range set by the addition range setting unit 164 when the microcomputer 9 controls the main subject discrimination process or the exposure calculation process. When the microcomputer 9 performs the AF process, the charges of the pixels within the rectangular range set by the addition range setting unit 164 are added. A light reception signal corresponding to the added electric charge is output from the output circuit 165 for each set range. In this way, when one area sensor 16 is used for a plurality of applications, an output suitable for each application can be obtained from the area sensor 16.

  Further, when the microcomputer 9 controls the main subject discrimination process or the exposure calculation process, charges are added to the R, G, and B pixels within the square range. Thus, by adding the charge of each pixel having the same spectral sensitivity characteristic to acquire color information, it is possible to appropriately perform main subject discrimination processing and exposure calculation processing. For example, by extracting the human face by detecting the skin color, eye color, lip color, etc., it is possible to determine that the face part is the main subject or to determine the exposure according to the hue. it can.

  When the microcomputer 9 performs the AF process, the charge of each pixel having the same spectral sensitivity characteristic may be added as in the case where the main subject determination process or the exposure calculation process is performed. In such a case, the added charges are further added to pixels having different spectral sensitivity characteristics by subsequent processing, and AF processing is performed based on the addition result. For example, the focus detection device 5 is provided with a second adder circuit, and the second adder circuit allows each range to be determined based on the received light amounts of R, G, and B output from the output circuit 165 for each set range. The total charge is calculated, and a signal corresponding to the calculation result is output. Thus, based on the signal output from the second adder circuit, the microcomputer 9 obtains the defocus amount and detects the focus adjustment state of the photographing lens 1. Based on the defocus amount detected by such a method, the microcomputer 9 can execute the AF process. Therefore, even when the area sensor 16 cannot add pixels for pixels having different spectral sensitivity characteristics, the defocus amount can be detected.

  Although the example of the area sensor 16 using the CCD type two-dimensional image sensor has been described above, the same processing can be performed when a CMOS is used for the area sensor 16. Further, when CMOS is used, the addition range setting unit 164 sets an addition range for the address designation unit, adds the charges of the pixels designated by the address designation unit as a voltage, and outputs the voltage.

  Even when the microcomputer 9 uses the image sensor 12 instead of the area sensor 16 to perform AF processing, main subject discrimination processing, or exposure calculation processing, the same method as described above can be used. That is, when AF processing is performed in the mirror-up state as shown in FIG. 2, a rectangular range as shown in FIGS. 5 to 7 is set in the image sensor 12, and the charges of the pixels in the range are collected together. to add. However, since the image quality is affected, in this case, it is better to perform addition using an ASIC at a later stage. Based on the charges thus added, the microcomputer 9 executes AF processing. At this time, either the contrast detection method or the phase difference detection method may be used. On the other hand, when the main subject discrimination process and the exposure calculation process are performed, a square range as shown in FIGS. 8 to 10 is set in the image sensor 12, and each of the R, G, and B pixels within the range is set. Add the charge for. On the basis of the charges thus added, the microcomputer 9 controls the main subject discrimination processing or exposure calculation processing. By doing in this way, when using one image sensor 12 for a plurality of uses, an output suitable for each use can be obtained from the image sensor 12.

  Next, a method for detecting the defocus amount by the focus detection device 5 will be described. FIG. 11 is a perspective view showing the configuration of the focus detection optical system in the focus detection device 5, and FIG. 12 is an optical path diagram of the focus detection optical system of FIG. 11 viewed from the y-axis direction. The light flux from the object field passes through the exit pupil region 1 a of the photographing lens 1 and forms an image in the vicinity of the field mask 26. The light beam that has passed through the field opening 26a of the field mask 26 is transmitted through the condenser lens 22, and the diaphragm openings 23a and 23b and the re-imaging of the diaphragm mask 23 that are arranged at positions almost conjugate with the exit pupil regions 1a and 1b of the photographing lens. The image is divided by passing through re-imaging lenses 24 a and 24 b of the optical system 24, and forms an image on the line sensor 25 set in the sensor array unit 161 of the area sensor 16. The line sensor 25 represents a pixel range used for AF.

  As described above, the light beam from the object scene is divided into a pair of secondary images in the x-axis direction. Therefore, detecting the state of the pair of secondary images detects the focus adjustment state of the photographing lens 1 with respect to a subject whose luminance changes in the x-axis direction. The focus adjustment state of the photographic lens 1 can be detected by photoelectrically converting a pair of subject images formed on the line sensor 25.

  That is, at the time of so-called in-focus, in which the photographing lens 1 forms a sharp image on a planned imaging surface equivalent to the imaging surface, a pair of subject images on the line sensor 25 are displayed in front pins as shown in FIG. An image is formed at a predetermined interval L0 between the state and the rear pin state. Further, in the case of a so-called front pin state in which the photographic lens 1 forms a sharp image before the planned image plane, a pair of subject images on the line sensor 25 are aligned as shown in FIG. An image is formed at an interval L1 shorter than the interval L0 at the time of focusing. On the other hand, when the photographing lens 1 forms a sharp image after the planned image plane, the pair of subject images on the line sensor 25 has an interval L2 longer than the interval L0 at the time of focusing. To form an image. Accordingly, the pair of subject images are photoelectrically converted by the line sensor 25 to be converted into electrical signals, and the correlation calculation or the like is performed from these electrical signals to determine the relative positional deviation amount between the pair of subject images. The focus adjustment state of the taking lens 1 is detected.

  In the above, the images 28a and 28b of the pair of field openings 26a are projected on the sensor array portion 161 as shown in FIG. Subject images are formed only inside the pair of images 28a and 28b. Therefore, when performing the main subject discrimination process or the exposure calculation process, the microcomputer 9 selects either one of the pair of images 28a or 28b and uses the detection result of the subject image formed on the inside thereof. To do.

  In the sensor array unit 161, the pixel range corresponding to the line sensor 25 is set corresponding to the focus detection area set in the screen by the photographing lens 1. That is, the addition range setting unit 164 sets a pixel range corresponding to the focus detection region set in the screen by the photographing lens 1 among the plurality of pixels of the sensor array unit 161 to the transfer circuit of the sensor array unit 161. Set. By limiting the range of pixels to be set in this way, unnecessary charge accumulation amount can be prevented from being read and AF processing can be performed in a short time.

  Here, the position of the focus detection area may be changeable. In this case, the addition range setting unit 164 changes the pixel range set for the transfer circuit of the sensor array unit 161 in accordance with the change of the position of the focus detection region. In this way, even when the position of the focus detection area is changed, the focus detection device 5 can correctly detect the defocus amount.

  As described above, at the time of AF processing, the defocus amount is obtained by the microcomputer 9, and the focus adjustment state of the image by the photographing lens 1 is detected. On the other hand, in the main subject discrimination process and the exposure calculation process, the microcomputer 9 detects the state of the image by the photographing lens 1 such as the shape, hue, and brightness. Thus, the addition range setting unit 164 sets the pixel range to be added to the sensor array unit 161 according to the state detected by the microcomputer 9. Since it did in this way, when using one area sensor 16 for a plurality of uses, the output suitable for each use can be obtained from area sensor 16. The same applies when the image sensor 12 is used.

According to the embodiment described above, the following operational effects are obtained.
(1) In the area sensor 16, in the sensor array unit 161, a plurality of photoelectric conversion units (pixels) that accumulate charges according to the amount of received light are arranged. The charges of any one of the pixels are added by the vertical transfer circuit 163 and the horizontal transfer circuit 162. Thus, the range of pixels to which charges are added by the vertical transfer circuit 163 and the horizontal transfer circuit 162 is set by the addition range setting unit 164. Since it did in this way, when using one area sensor 16 for a some use, the output suitable for every use can be obtained from the area sensor 16. FIG.

(2) The microcomputer 9 sets the defocus amount indicating the focus adjustment state of the photographing lens 1 based on the light reception signal output from the area sensor 16 according to the charges added by the vertical transfer circuit 163 and the horizontal transfer circuit 162. To detect. Since it did in this way, the focus adjustment of the photographic lens 1 can be performed appropriately.

(3) The microcomputer 9 may be provided with a second addition circuit. In this case, the microcomputer 9 adds the charges of the respective pixels having the same spectral sensitivity characteristics by the vertical transfer circuit 163 and the horizontal transfer circuit 162, and further adds the added charges to the pixels having different spectral sensitivity characteristics by the second addition circuit. The defocus amount can be detected based on the addition result. In this way, the defocus amount can be detected by the microcomputer 9 even when the area sensor 16 cannot add pixels for pixels having different spectral sensitivity characteristics.

(4) The addition range setting unit 164 sets, for the sensor array unit 161, a pixel range corresponding to the focus detection region set in the screen by the photographing lens 1 among the plurality of pixels of the sensor array unit 161. It was decided. Since it did in this way, reading of an unnecessary charge accumulation amount can be prevented and AF processing can be performed in a short time.

(5) The position of the focus detection area may be changeable. In this case, the addition range setting unit 164 changes the pixel range set for the sensor array unit 161 in accordance with the change in the position of the focus detection region. In this way, even if the position of the focus detection area is changed, the defocus amount can be correctly detected by the microcomputer 9.

(6) The addition range setting unit 164 performs vertical transfer circuit 163 and horizontal transfer according to the type of control executed by the microcomputer 9, the brightness of incident light, the focal length of the photographing lens 1, the photographing distance by the photographing lens 1, and the like. The range of pixels to which charges are added by the circuit 162 is set for the sensor array unit 161. Since it did in this way, an appropriate range can be set according to a situation.

(7) The microcomputer 9 performs control of at least one of main subject discrimination processing and exposure calculation processing for discriminating an image by the photographing lens 1, and AF processing for focus detection control of the photographing lens 1. When the microcomputer 9 controls the main subject determination process or the exposure calculation process, the addition range setting unit 164 sets a range in which a plurality of pixels are substantially square with respect to the sensor array unit 161 and the microcomputer 9 performs the AF process. When performing the above, a rectangular range is set for the sensor array portion 161. In this way, in the main subject discrimination process or the exposure calculation process, the horizontal direction and the vertical direction can be processed with the same resolution. In the AF process, the charge accumulation time and readout time are shortened, The resolution can be improved.

(8) The vertical transfer circuit 163 and the horizontal transfer circuit 162 add the charges of pixels having the same spectral sensitivity characteristics when the microcomputer 9 controls the main subject determination process or the exposure calculation process. Since it did in this way, color information can be acquired and the main subject discrimination processing and exposure calculation processing can be appropriately performed.

(9) The addition range setting unit 164 indicates the pixel range to be added by the vertical transfer circuit 163 and the horizontal transfer circuit 162 to the sensor array unit 161 according to the state of the image by the photographing lens 1 detected by the focus detection device 5. To set. Since it did in this way, when using one area sensor 16 for a plurality of uses like the above, the output suitable for every use can be obtained from area sensor 16.

-Modification-
In the above-described embodiment, the microcomputer 9 detects the amount of light received from the photographing lens 1 using the area sensor 16 or the image sensor 12, and performs AF processing, main subject discrimination processing, or exposure calculation processing. did. However, instead of the area sensor 16 or the image sensor 12, the received light amount from the photographing lens 1 is detected by an EVF (Electronic View Finder) sensor, and each process of the microcomputer 9 is performed based on the detection result. You may make it perform.

  FIG. 13 is a configuration diagram of a camera according to this modification. In the camera shown in FIG. 13, the camera body 200 is provided with an EVF sensor 17 and an EVF optical system 20 instead of the pentaprism 6, the eyepiece lens 15, and the pentaprism 6 of FIG. 1. Of the light incident on the camera body 200 via the photographing lens 1, the light reflected by the main mirror 13 is an EVF sensor provided by the EVF optical system 20 at a position optically equivalent to the image sensor 12. 17 is imaged. The EVF sensor 17 captures a subject image before photographing and displays it on the rear monitor 18.

  The EVF sensor 17 has the same structure as the area sensor 16 and the image sensor 12. Therefore, in this EVF sensor 17, by setting the range of pixels to which charges are added as described above, when one EVF sensor 17 is used for a plurality of uses, an output suitable for each use is used for the EVF. It can be obtained from the sensor 17. Note that when performing AF processing, a contrast detection method may be used. Alternatively, an array of focus detection pixels for performing pupil division type phase difference detection may be mixed in the image pickup pixel array of the image sensor 12, and the defocus amount may be detected using the focus detection pixels. Alternatively, the AF processing may be performed using the focus detection device 5.

  In the embodiments and modifications described above, the lens barrel has been described as a replaceable camera. However, the present invention is not limited to this, and a lens-integrated camera may be used. Further, the present invention is not limited to a digital camera using an image sensor, and may be applied to a film camera.

  The embodiments and modifications described above are merely examples, and the present invention is not limited to these contents as long as the features of the invention are not impaired. Other aspects conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention.

It is a block diagram of the camera by one embodiment of this invention. It is a figure which shows the mode of operation | movement of the camera at the time of imaging | photography. 1 is a schematic configuration diagram of an area sensor using a CCD type two-dimensional image sensor. FIG. It is a flowchart of an addition mode determination flow. It is a figure which shows the example of the range of the pixel set when performing AF process at the time of low brightness | luminance. It is a figure which shows the example of the range of the pixel set when performing AF process at the time of high brightness | luminance. It is a figure which shows the example of the range of the pixel set when performing AF process at the time of wide lens use. It is a figure which shows the example of the range of the pixel set in the discrimination | determination process of a main subject, or an exposure calculation process, and shows a mode that an electric charge is added about R pixel. It is a figure which shows the example of the range of the pixel set in the discrimination | determination process of a main subject, or an exposure calculation process, and has shown a mode that an electric charge is added about the pixel of G. It is a figure which shows the example of the range of the pixel set in the discrimination | determination process of a main subject, or an exposure calculation process, and has shown a mode that an electric charge is added about the B pixel. It is a perspective view which shows the structure of a focus detection optical system. It is the optical path figure which looked at the focus detection optical system from the y-axis direction. It is a block diagram of the camera by the modification of this invention.

Explanation of symbols

1: photographing lens, 2: aperture, 3: drive mechanism, 4: lens data section, 5: focus detection device,
6: Penta prism, 7: Signal processing unit, 8: Drive motor, 9: Microcomputer,
10: coupling unit, 11: shutter, 12: image sensor, 13: main mirror,
14: Submirror, 15: Eyepiece, 16: Area sensor, 17: EVF sensor,
18: Rear monitor, 19: Viewfinder screen, 20: EVF optical system,
100: Lens part, 200: Camera body

Claims (16)

A light receiving element in which a plurality of photoelectric conversion units that accumulate electric charges according to the amount of received light are arranged,
Adding means for adding the charges of the plurality of photoelectric conversion units;
An addition range setting unit that sets a range of the photoelectric conversion unit that adds charges by the addition unit. A light receiving element according to claim 1;
And an output means capable of outputting the charges added corresponding to the different ranges. A light receiving element according to claim 1;
A focus detection optical system for guiding light through the imaging optical system to the light receiving element;
A focus detection apparatus comprising: focus detection means for detecting a focus adjustment state of the imaging optical system based on a signal corresponding to the charge added by the addition means. The focus detection apparatus according to claim 3,
The plurality of photoelectric conversion units have different spectral sensitivity characteristics,
The adding means adds the charges of the photoelectric conversion units having the same spectral sensitivity characteristic among the photoelectric conversion units within the range,
A second addition means for adding the charges added by the addition means for the photoelectric conversion units having different spectral sensitivity characteristics;
The focus detection apparatus, wherein the focus detection unit detects the focus adjustment state based on a signal corresponding to the electric charge added by the second addition unit. The focus detection apparatus according to claim 3 or 4,
The addition range setting means sets a range of a photoelectric conversion unit corresponding to a focus detection region set in a screen by the imaging optical system among the plurality of photoelectric conversion units. . The focus detection apparatus according to claim 5,
The position of the focus detection area in the screen can be changed,
The focus detection apparatus characterized in that the addition range setting means changes the range according to a change in the position of the focus detection area. In the focus detection apparatus according to any one of claims 3 to 6,
The focus detection apparatus characterized in that the addition range setting means sets the range in accordance with a focal length of the imaging optical system. A light receiving element according to claim 1;
A camera having control means capable of executing a plurality of different controls based on the charge,
The camera according to claim 1, wherein the addition range setting means sets the range according to a type of the control executed by the control means. A light receiving element according to claim 1;
In a camera including an imaging optical system that forms an image of a light beam on the light receiving element,
The camera according to claim 1, wherein the addition range setting means sets the range in accordance with a focal length of the imaging optical system. The camera according to claim 8, wherein
An imaging optical system that forms an image of a light beam on the light receiving element;
The camera according to claim 1, wherein the control means performs control of at least one of image discrimination processing and exposure calculation processing by the imaging optical system, and focus detection control of the imaging optical system. The camera of claim 10, wherein
When the control unit controls the determination process or the exposure calculation process, the addition range setting unit sets the substantially square range in the plurality of photoelectric conversion units, and the control unit controls the focus detection control. A camera characterized by setting a rectangular range when performing. The camera according to claim 10 or 11,
The plurality of photoelectric conversion units have different spectral sensitivity characteristics,
The addition unit adds the charges of the photoelectric conversion units having the same spectral sensitivity characteristics when the control unit controls the determination process or the exposure calculation process. The camera according to any one of claims 8 to 12,
A luminance detecting means for detecting the luminance of the incident light;
The camera according to claim 1, wherein the addition range setting unit sets the range in accordance with the luminance detected by the luminance detection unit. The camera according to any one of claims 9 to 13,
The camera according to claim 1, wherein the addition range setting means sets the range according to a shooting distance by the imaging optical system. The camera according to any one of claims 10 to 14,
The camera according to claim 1, wherein the addition range setting means sets the range in accordance with a focal length of the imaging optical system. A light receiving element in which a plurality of photoelectric conversion units that accumulate charges according to light incident through the imaging optical system are arranged;
Adding means for adding the charges of the plurality of photoelectric conversion units;
Detecting means for detecting a first state of the image by the imaging optical system based on the charge and a second state different from the first state;
An addition range setting unit configured to set a range of the photoelectric conversion unit added by the addition unit according to a state detected by the detection unit.

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