JP4994905B2 - Imaging device - Google Patents

Description

  The present invention relates to an image pickup apparatus in which a light beam from an image pickup optical system is received by a pair of light receiving elements having different spectral sensitivity characteristics, information on a light source is generated from the light reception output, and information for focus control is generated. .

  An imaging apparatus such as a single-lens reflex camera often employs a focus detection method called a TTL phase difference detection method. In the TTL phase difference detection system, two images are formed on a pair of light receiving element arrays by re-imaging the light flux from the imaging optical system by the pair of re-imaging optical systems, and the relative positions of the two images By detecting the difference (phase difference), the defocus amount of the imaging optical system is obtained.

  In general, in an imaging optical system and a re-imaging optical system (also referred to as a focus detection optical system), various aberrations such as chromatic aberration are corrected in a visible wavelength range from 400 nm to 700 nm centering on the d line (587 nm). For this reason, it is rare that aberrations in a wavelength range other than the visible wavelength range, for example, near-infrared wavelength range, are well corrected. In this case, the relative ratio of near-infrared light to visible light differs in daylight, under a light source with a low color temperature such as a tungsten lamp, and under a light source with a high color temperature such as a fluorescent lamp. Different focus detection results are often obtained.

  Therefore, as disclosed in Patent Document 1, a pair of light source detection light-receiving elements having different spectral sensitivity characteristics are arranged in the vicinity of the focus detection light-receiving element array, and the color temperature of the light source is determined from the ratio of the outputs. It is preferable to detect and correct the focus detection result based on the detection result of the color temperature.

  In Patent Document 2, two light receiving regions having different spectral sensitivity characteristics are formed in the light receiving element by applying a dye filter having different spectral transmittance characteristics to one light source detecting light receiving element. A technique for detecting the color temperature of a light source is disclosed.

  However, the illuminance distribution on the light receiving element due to the light beam that passes from the subject through the imaging optical system and the re-imaging optical system and reaches the light receiving element is affected by the imaging optical system and the re-imaging optical system. May not be uniform (becomes uneven). In this case, the output of the light receiving element varies depending on the position where the image of the subject whose color temperature is to be detected is formed in the light receiving element. For this reason, an error occurs in the detection result of the color temperature.

Patent Document 3 discloses a focus detection device provided with illuminance distribution correction means for correcting illuminance distribution imbalance with respect to two light receiving element arrays.
Japanese Patent No. 2900390 Japanese Patent No. 2556681 JP-A 63-276010

  However, the focus detection device disclosed in Patent Document 3 only corrects the illuminance distribution unbalance with respect to the two light receiving element arrays, and does not correct the uneven illuminance distribution in one light receiving element. Absent.

  The present invention reduces the change in output of the light receiving element due to non-uniform illuminance distribution (unevenness in the amount of received light) in the light receiving element for detecting the light source, and provides a good light source regardless of the position of the subject image and the size of the subject image. Provided is an imaging apparatus capable of performing detection and further performing highly accurate focus control.

An imaging apparatus according to one aspect of the present invention is a pair of imaging optical systems that forms an image of a light beam from an imaging optical system, the imaging apparatus including a plurality of pixels and having the same spectral sensitivity characteristics, and the focal state of the imaging optical system A pair of imaging optical systems for guiding a light beam to a pair of first light receiving elements that output a signal for detecting the light , and a pair of spectral sensitivity characteristics that respectively receive the light beams from the pair of imaging optical systems A pair of second light receiving elements disposed in the vicinity of each of the first light receiving elements, and detection means for detecting light sources based on outputs from the pair of second light receiving elements. Have Each of the second light receiving elements is a light shielding member for reducing a change in output accompanying a change in the amount of received light according to a light receiving position generated by the imaging optical system and the imaging optical system . has a light shielding member that each light receiving element does not have the said light blocking member, the amount of light received at the second respective light receiving elements, small Te direction of each odor perpendicular to the base length direction and the direction It is characterized by having a shape in which the light shielding area becomes smaller as there is no position.

An imaging apparatus according to another aspect of the present invention is a pair of imaging optical systems that forms an image of a light beam from the imaging optical system, the imaging optical system including a plurality of pixels and having equal spectral sensitivity characteristics. A pair of imaging optical systems for guiding a light beam to a pair of first light receiving elements that output a signal for detecting a focal state of the light beam , and spectral sensitivity characteristics for receiving the light beams from the pair of imaging optical systems, respectively. A pair of different light receiving elements , a pair of second light receiving elements disposed in the vicinity of each of the first light receiving elements , and detection of the light source based on outputs from the pair of second light receiving elements Detecting means. And each 2nd light receiving element is a light-receiving part shape for reducing the change of the output accompanying the change of the 2nd received light quantity according to the light reception position which arises with an imaging optical system and an imaging optical system , Comprising: Each of the first light receiving elements has a light receiving part shape, and the light receiving part shape is such that the amount of light received by each of the second light receiving elements is in a base line length direction and a direction orthogonal to the direction. as each not less Te odor position, characterized by having a receiving section shaped receiving area is increased.

  It has a pair of light-receiving element arrays for focus detection that respectively receive light beams through the imaging optical system and the pair of imaging optical systems, and is based on the output from the light-receiving element array for focus detection and information on the light source. Thus, an imaging apparatus that generates information for performing focus control of the imaging optical system also constitutes another aspect of the present invention.

  According to the present invention, the change in the amount of light received in the light receiving element for detecting the light source, that is, the change in the output of the light receiving element due to the nonuniform illuminance distribution is reduced. Regardless of this, good light source detection can be performed. Therefore, highly accurate focus control using the light source detection result (information on the light source) can be performed.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  First, FIG. 8 shows an imaging system including a single-lens reflex digital camera (imaging apparatus: hereinafter simply referred to as a camera) that is Embodiment 1 of the present invention. The imaging system includes a camera and an interchangeable lens attached to the camera.

  In the figure, reference numeral 1 denotes a camera, and an interchangeable lens 11 is mounted on the front surface thereof. In the camera 1, an image pickup device 9 including an optical component, a mechanical component, an electric circuit, and a CCD sensor or a CMOS sensor is housed.

  Reference numeral 2 denotes a main mirror, which is disposed obliquely in the imaging optical path in the viewfinder observation state and retracts out of the imaging optical path in the imaging state. Further, the main mirror 2 is a half mirror, and when it is disposed in the imaging optical path, it transmits about half of the light beam incident from the interchangeable lens 11. Reference numeral 20 denotes a sub mirror, which is disposed obliquely in the imaging optical path behind the main mirror 2 in the finder observation state, and retracts out of the imaging optical path in the imaging state. In the imaging state, the sub mirror 20 bends the light beam transmitted through the main mirror 2 downward and guides it to a focus detection unit described later.

  Reference numeral 3 denotes a focusing plate disposed on the planned imaging plane of the interchangeable lens 11, and reference numeral 4 denotes a pentaprism for bending the finder optical path. Reference numeral 5 denotes an eyepiece. A finder optical system is configured by the focus plate 3, the pentaprism 4, and the eyepiece lens 5, and the photographer can observe the subject image by observing the focus plate 3 through the eyepiece lens 5.

  Reference numeral 7 denotes a photometric sensor for measuring the luminance of the subject, and reference numeral 6 denotes an imaging lens that forms a subject image on the photometric sensor 7 with the light flux from the pentaprism 4.

  Reference numeral 8 denotes a focal plane shutter that controls the amount and timing of incidence of a light beam on the image sensor 9.

  Reference numeral 25 denotes a focus detection unit (focus detection apparatus), which includes a secondary imaging lens unit 26 as an imaging optical system, a reflection mirror 27, and a sensor unit 29.

  The secondary imaging lens unit 26 converts a pair or a plurality of pairs of secondary subject images (A image, B image) to a light beam from the imaging optical system in the interchangeable lens 11 (light beam reflected by the sub mirror 20) as a sensor unit. 29 is formed. The focus detection unit 25 generates phase difference information corresponding to the focus state of the imaging optical system in the interchangeable lens 11 based on the relative position difference (phase difference) between the A image and the B image. The phase difference information is sent to the camera microcomputer 30 as a controller.

  The camera microcomputer 30 calculates the defocus amount of the imaging optical system from the phase difference information, and further calculates the drive amount and drive direction of the focus lens 12 for obtaining the focus from the defocus amount. Thereby, focus control is performed by a so-called TTL phase difference detection method.

  The camera microcomputer 30 that also functions as a detection unit that performs detection relating to the light source corrects the calculated defocus amount based on a detection result of color temperature (information relating to the light source) described later, and the corrected defocus. Focus control is performed based on the amount. That is, the camera microcomputer 30 generates information about the light source (in this case, information indicating the color temperature) based on outputs from a pair of light receiving elements for detecting the light source described later. Then, focus control of the imaging optical system is performed based on an output from a light receiving element array for focus detection described later and information on the light source.

  In the correction of the defocus amount, for example, the type of light source (sun, fluorescent lamp, tungsten lamp, etc.) is determined based on the color temperature, and a correction value corresponding to the color temperature of the light source is added (or subtracted) to the defocus amount. Can be done.

  In this embodiment, the color temperature is used as information about the light source, but the information about the light source is not limited to the color temperature.

  A mount contact group 10 serves as a communication interface between the camera 1 and the interchangeable lens 11.

  In the interchangeable lens 11, lens units 12 to 14 and a diaphragm 15 constituting an imaging optical system are arranged. A first lens unit (hereinafter referred to as a focus lens) 12 closest to the subject adjusts the focus position by moving in the optical axis direction. The second lens unit 13 moves in the optical axis direction and performs zooming of the imaging optical system. Reference numeral 14 denotes a fixed third lens unit. The diaphragm 15 adjusts the amount of light by changing the aperture diameter.

  A focus drive motor 16 moves the focus lens 12 in the optical axis direction. Reference numeral 17 denotes an aperture drive motor for changing the aperture diameter of the aperture 15. Reference numeral 18 denotes a distance encoder, and a brush 19 attached to the focus lens 12 slides on the distance encoder 18 to output a signal corresponding to the position of the focus lens 12. The subject distance can be detected based on position information from the distance encoder 18 in a state where the focus lens 12 is controlled to the in-focus position. The interchangeable lens 11 is also provided with a zoom position detector (not shown) that detects the position of the second lens unit 13, and obtains the focal length of the imaging optical system based on a signal from the zoom position detector. You can also

  FIG. 1 shows a sensor unit 29 provided in the focus detection unit 25. The sensor unit 29 is configured based on a semiconductor substrate.

  Reference numerals 101a and 101b denote a pair of light receiving element arrays (light receiving element arrays for focus detection) for detecting the focus state at the center of the imaging screen, and a plurality of photodiodes (in the one-dimensional horizontal direction (baseline length direction)). Light receiving elements) are arranged.

  The light receiving element array 101a photoelectrically converts the above-described A image and outputs an electric signal corresponding to the position of the A image. The light receiving element array 101b photoelectrically converts the above-described B image and outputs an electrical signal corresponding to the position of the B image. The camera microcomputer 30 can calculate the defocus amount of the imaging optical system by detecting the relative position difference between the A and B images, that is, the interval (phase difference) from these electrical signals.

  Reference numerals 102a and 102b denote a pair of light receiving element arrays for detecting the focus state of the right portion of the imaging screen, and are configured by arranging a plurality of photodiodes in a vertical one-dimensional direction (baseline length direction). . Note that, in the focal plane shown in FIG. 1, the upper, lower, left, and right sides of the image are reversed, so that the light receiving element arrays 102a and 102b are shown on the left side of the drawing.

  The light receiving element array 102a photoelectrically converts the above-described A image and outputs an electrical signal corresponding to the position of the A image. The light receiving element array 102b photoelectrically converts the above-described B image and outputs an electric signal corresponding to the position of the B image. By detecting the phase difference between the A and B images from these electrical signals, the camera microcomputer 30 can calculate the defocus amount of the imaging optical system.

  Reference numerals 103a and 103b denote a pair of light receiving element arrays for detecting the focus state of the left portion of the imaging screen, and are configured by arranging a plurality of photodiodes in the vertical one-dimensional direction (baseline length direction). .

  The light receiving element array 103a photoelectrically converts the above-described A image and outputs an electrical signal corresponding to the position of the A image. The light receiving element array 103b photoelectrically converts the above-described B image and outputs an electric signal corresponding to the position of the B image. By detecting the phase difference between the A and B images from these electrical signals, the camera microcomputer 30 can calculate the defocus amount of the imaging optical system.

  104a and 104b are a pair of light receiving elements for light source detection, which are arranged in the vicinity of the light receiving element arrays 101a and 101b and have different spectral sensitivity characteristics.

  The light receiving element 104a has a spectral sensitivity characteristic of silicon not coated with a color filter or the like, mainly sensitivity to the visible wavelength region. On the other hand, the light receiving element 104b has a sensitivity in a wavelength region from red to infrared by applying a red dye filter, for example. The camera microcomputer 30 can detect the color temperature of the subject (that is, the light source that illuminates the subject) located below the center of the shooting screen from the ratio of the outputs of the light receiving elements 104a and 104b.

  Reference numerals 105a and 105b denote a pair of light-receiving elements for detecting light sources having different spectral sensitivity characteristics, which are arranged in the vicinity of the light-receiving element arrays 101a and 101b. The spectral sensitivity characteristics are the same as and different from the light-receiving elements 104a and 104b, respectively. Have For this reason, it is possible to detect the color temperature of the subject located above the center of the shooting screen from the ratio of the outputs of the two light receiving elements 105a and 105b.

  106a and 106b are a pair of light-receiving elements for detecting light sources having different spectral sensitivity characteristics arranged in the vicinity of the light-receiving element arrays 102a and 102b. The same spectral sensitivity characteristics as the light receiving elements 104a and 104b are different from each other. Have For this reason, it is possible to detect the color temperature of the subject located on the right side of the shooting screen from the ratio of the outputs of the two light receiving elements 106a and 106b.

  107a and 107b are a pair of light-receiving elements for detecting light sources having different spectral sensitivity characteristics arranged in the vicinity of the light-receiving element arrays 103a and 103b. The spectral sensitivity characteristics are the same as and different from the light-receiving elements 104a and 104b, respectively. Have Therefore, it is possible to detect the color temperature of the subject located on the left side of the shooting screen from the ratio of the outputs of both the light receiving elements 107a and 107b.

  Further, when the subject for detecting the color temperature has a size that occupies almost the entire photographing screen, the ratio of the output of the light receiving elements 104a, 105a, 106a and the output of the light receiving elements 104b, 105b, 106b is compared. If the color temperature is detected, the detection accuracy can be increased.

  The secondary imaging lens unit 26 constituting the re-imaging optical system of the focus detection unit 25 will be described with reference to FIG.

  In the figure, reference numerals 201a and 201b denote a pair of 2 for dividing a light beam that has passed through the imaging optical system from the subject in the center of the imaging screen and entered the focus detection unit 25 and re-imaged on the sensor unit 29. This is the next imaging lens. The light beam from the imaging optical system is re-imaged on the light receiving element array 101a and the light receiving elements 104a and 105a by the secondary imaging lens 201a, and the light receiving element array 101b and the light receiving element 104b by the secondary imaging lens 201b. Reimaged on 10ba.

  Reference numerals 202 a and 202 b denote a pair of secondary imaging lenses for dividing a light beam that has passed through the imaging optical system from the subject on the right side of the imaging screen and entered the focus detection unit 25 and re-imaged on the sensor unit 29. is there. The light beam from the imaging optical system is re-imaged on the light-receiving element array 102a and the light-receiving element 106a by the secondary imaging lens 202a, and re-imaged on the light-receiving element array 102b and the light-receiving element 106b by the secondary imaging lens 202b. Imaged.

  Reference numerals 203 a and 203 b denote a pair of secondary imaging lenses for dividing a light beam that has passed through the imaging optical system and entered the focus detection unit 25 from the subject on the left side of the imaging screen and re-imaged on the sensor unit 29. is there. The light beam from the imaging optical system is re-imaged on the light receiving element array 103a and the light receiving element 107a by the secondary imaging lens 203a, and re-imaged on the light receiving element array 103b and the light receiving element 107b by the secondary imaging lens 203b. Imaged.

  In FIG. 2, reference numeral 215 denotes an exit pupil of the imaging optical system. Moreover, the solid line straight line in the figure indicates the optical axis of the imaging optical system. Reference numerals 211a and 211b denote positions where the light beams incident on the secondary imaging lenses 201a and 201b pass through the exit pupil 215 of the imaging optical system. Reference numerals 212a and 212b denote positions where the light beams incident on the secondary imaging lenses 202a and 202b pass through the exit pupil 215 of the imaging optical system. Reference numerals 213a and 213b denote positions where the light beams incident on the secondary imaging lenses 203a and 203b pass through the exit pupil 215 of the imaging optical system.

  FIG. 3A shows an example of the illuminance distribution (change in the amount of received light) in the baseline length direction on the light receiving elements 104a and 104b. The horizontal axis indicates the position on the light receiving elements 104a and 104b, and the vertical axis indicates the illuminance (the amount of received light) for each position. In addition, a curve a in the figure indicates the illuminance distribution on the light receiving element 104a, and a curve b indicates the illuminance distribution on the light receiving element 104b.

  Further, FIG. 3B shows a positional relationship between the light receiving elements 104a and 104b and the light receiving element arrays 101a and 101b. In the light receiving elements 104a and 104b, the left end positions of the light receiving elements 104a and 104b are assumed to be x0, and the positions at regular intervals therefrom are assumed to be X1, X2, and X3. The position X2 is a position through which the optical axes of the secondary imaging lenses 201a and 201b pass.

  The light beam imaged on the light receiving element 104a passes through a position 211a shifted from the optical axis in the exit pupil 215 of the imaging optical system and enters the secondary imaging lens 201a. The light beam formed on the light receiving element 104b passes through a position 211b shifted from the optical axis in the exit pupil 215 of the imaging optical system and enters the secondary imaging lens 201b.

  Since the light beams that enter the positions X0 to X3 on the light receiving elements 104a and 104b have different angles to enter the imaging optical system and the secondary imaging lenses 201a and 201b, the imaging optical system and the secondary imaging lenses 201a and 201b have different angles. to be influenced.

  In general, the amount of light flux passing through a lens varies according to the incident angle to the lens. Specifically, the incident angle θ decreases in proportion to the fourth power of COSθ. For this reason, the illuminance distribution on each light receiving element by the light flux that passes through the imaging optical system and the secondary imaging lenses 201a and 201b and reaches the light receiving elements 104a and 104b is shown by the curves a and b in FIG. 3A. It becomes non-uniform and non-uniform. In other words, the amount of received light varies depending on the light receiving position on each light receiving element.

  In addition, since the light receiving elements 104a and 104b are arranged symmetrically with respect to the optical axis of the imaging optical system, the illuminance distribution on the light receiving elements 104a and 104b is symmetrical with respect to the respective positions X2.

  Even in the direction orthogonal to the baseline length direction, illuminance distribution is non-uniform (irradiance unevenness or unevenness in received light amount) for the same reason, but the description here is omitted. In addition, here, the pair of light receiving elements 104a and 104 of the four pairs of light source detecting light receiving elements are shown as representatives, but the illuminance unevenness similarly occurs in other pairs of light receiving elements. In particular, illuminance unevenness occurs more remarkably on light receiving elements that receive a light beam passing through a position far away from the optical axis of the imaging optical system, such as the light receiving elements 106a, 106b, 107a, and 107b.

  When the image of the subject that is the light source detection target is sufficiently larger than each light receiving element, such uneven illuminance is not a problem, but usually the subject image is often smaller than the light receiving element. In this case, when the imaging position of the subject image is X2, the illuminance on the light receiving element 104a and the illuminance on the light receiving element 104b are B2, which are equal to each other. However, when the imaging position of the subject image is X1, the illuminance on the light receiving element 104a is B3, and the illuminance on the light receiving element 104b is B1 (> B3). Further, when the imaging position of the subject image is X3, the illuminance on the light receiving element 104a is B1, and the illuminance on the light receiving element 104b is B3 (<B1).

  As described above, the illuminance varies depending on the imaging position on the light receiving elements 104a and 104 even with the light flux from the same subject, so the ratio of the outputs from the light receiving elements 104a and 104b differs, and the light source detection result changes. Resulting in.

  Therefore, in this embodiment, in order to eliminate such a light source detection error due to uneven illuminance, a light shielding mask (light shielding member) is provided for each light receiving element as shown in FIG. FIG. 4 shows a light shielding mask 110 formed on the light receiving elements 104a and 104b and the light receiving elements 105a and 105b. FIG. 4 also shows light receiving element arrays 101a and 101b for focus detection.

  In the light shielding mask 110 formed on each light receiving element, the light shielding area increases as the illuminance of each light receiving element shown in FIG. 3A increases (the amount of received light) increases. The smaller the position, the smaller the light shielding area.

  Since the light receiving element 104a has the highest illuminance at the position X3, the light shielding mask 110 on the light receiving element 104a has the largest light shielding area at the position X3 (mask length in a direction orthogonal to the base line length direction), and the base line. It has a shape in which the light shielding area decreases toward both ends in the long direction.

  Further, since the light receiving element 104b has the highest illuminance at the position X1, the light shielding mask 110 on the light receiving element 104b has the largest light shielding area at the position X1, and the light shielding area decreases toward both ends in the baseline length direction. Have

  The light shielding mask 110 on the light receiving elements 105a and 105b also has the same shape as the light shielding mask 110 on the light receiving elements 104a and 104b in the baseline length direction.

  By providing such a light shielding mask 110, in each light receiving element, the light receiving area (area of the opening) is smaller as the illuminance is higher, and conversely, the light receiving area is larger as the illuminance is lower.

  The light shielding mask 110 formed on the light receiving elements 104a and 104b has a shape in which the left and right are reversed. Further, the light shielding mask 110 formed on the light receiving elements 105a and 105b also has a shape in which the right and left sides are inverted.

  Further, the light shielding mask 110 formed on the light receiving elements 104a and 105a has a vertically inverted shape, and the light shielding mask 110 formed on the light receiving elements 104b and 105b has a vertically inverted shape.

  Note that uneven illuminance also occurs in the direction orthogonal to the base line length direction, so that each light shielding mask 110 has a larger light shielding area as the illuminance is higher, and conversely, the light shielding area is smaller as the illuminance is lower. Has a smaller shape.

  By providing such a light shielding mask 110 on each light receiving element, a change in output from each light receiving element due to a change in received light amount (irradiance unevenness) according to a light receiving position generated by the imaging optical system and the secondary imaging lens, That is, nonuniformity of sensitivity distribution is reduced. That is, a change in output from each light receiving element due to uneven illuminance is corrected. Specifically, as shown by a one-dot chain line c in FIG. 3A, almost the same level of output can be obtained regardless of the light receiving position.

  In the following description, such correction is referred to as uneven illuminance correction.

  The material of the light shielding mask 110 is not particularly limited. However, if the light shielding mask 110 is formed by using an aluminum wiring layer used for manufacturing a semiconductor, the light shielding mask is not caused without a significant increase in manufacturing cost. 110 can be formed.

  FIG. 5 shows a light receiving element for detecting a light source having a shape effective for correcting illuminance unevenness in a focus detection unit of a single-lens reflex camera that is Embodiment 2 of the present invention.

  The light receiving element for detecting a light source according to the present embodiment is mounted on the single-lens reflex camera described in the first embodiment. Further, since the light receiving element for detecting a light source described in the present embodiment has the same function as that of the first embodiment, the same reference numerals as those of the first embodiment are given.

  In this embodiment, the shape of the light receiving portions of the light receiving elements 104a, 104b, 105a, and 105b is the same as that of the portion (opening) that is not covered by the light shielding mask 110 in the first embodiment.

  That is, each light receiving element has a change in output from each light receiving element due to a change in the amount of received light (irradiance unevenness) corresponding to a light receiving position generated by the imaging optical system and the secondary imaging lens, that is, nonuniform sensitivity distribution. It has a light receiving portion shape that is reduced.

  FIG. 6 shows a light source detection light-receiving element having a semiconductor structure effective for correcting illuminance unevenness in a focus detection unit of a single-lens reflex camera that is Embodiment 3 of the present invention.

  The light receiving element for detecting a light source according to the present embodiment is mounted on the single-lens reflex camera described in the first embodiment. Further, since the light receiving element for detecting a light source described in the present embodiment has the same function as that of the first embodiment, the same reference numerals as those of the first embodiment are given.

  As described above, since the illuminance distribution on the light receiving elements 104a and 104b changes not only in the base line length direction but also in the direction perpendicular thereto, the illuminance unevenness can also be corrected two-dimensionally in the light receiving element of this embodiment. It has a semiconductor structure capable of.

  6 and 7, reference numeral 701 denotes an N-type well (first semiconductor) formed on a rectangular P-type semiconductor substrate serving as the base of the sensor unit 29 in accordance with the shape of the light receiving elements 104a and 104b. Reference numeral 601 denotes a plurality of P-type wells (second semiconductors) arranged in an island shape in the N-type well 701 (that is, in each light receiving element). The island shape can be paraphrased as discrete or separated.

  The plurality of P-type wells 601 are arranged in an island shape within the region of the N-type well 701 having the same shape as the opening of the light receiving element shown in the first embodiment and the light receiving section of the light receiving element shown in the second embodiment. The Further, the arrangement density is rough in a region where the illuminance is high and dense in a region where the illuminance is low. In other words, the P-type well 601 is arranged so that the density decreases as the position where the amount of received light is large, and conversely, the density increases as the position where the amount of received light is small.

  The sensitivity distribution of the light receiving element is determined by the spread of a depletion layer formed between the P-type well 601 and the N-type well 701. Therefore, in the region where the P-type wells 601 are densely arranged, the depletion layer overlaps, so that the sensitivity is high, and in the region where the P-type well 601 is roughly arranged, the depletion layer overlap is small and the sensitivity is low.

  FIG. 7 schematically shows the structure of the light receiving element shown in FIG. The N-type well 701 has a rectangular shape and basically determines the light receiving region of the light receiving element. In the N-type well 701, the P-type well 601 is arranged in an island shape. Reference numeral 703 denotes an aluminum wiring, which electrically connects the P-type well 601. Accordingly, the P-type well 601 arranged in an island shape is electrically handled as one P-type region. In FIG. 7, the aluminum wiring connected to the N-type well 701 is not shown.

  As described above, by varying the arrangement density of the P-type wells 601 arranged in an island shape according to the illuminance distribution, it is possible to perform illuminance unevenness correction that reduces nonuniform sensitivity distribution in the light receiving element.

  Moreover, although the several P-type well 601 shown in FIG.6 and FIG.7 has the mutually same magnitude | size, you may make a mutually different magnitude | size. That is, the size of the P-type well in the region with high illuminance may be reduced, and the size of each P-type well (each second semiconductor) in the region with low illuminance may be increased. In other words, the size of each P-type well 601 increases as the position where the amount of received light is small. Conversely, the size of each P-type well 601 may decrease as the position where the amount of received light is large. Even in this case, the arrangement density of P-type wells in a region with high illuminance may be rough, and the arrangement density of P-type wells in a region with low illuminance may be dense. It is possible to control the sensitivity distribution more finely by setting the size and arrangement density of the P-type well 601.

  The light receiving element shown in FIG. 7 is configured based on a P-type semiconductor substrate, but may be configured based on an N-type semiconductor substrate. In this case, a well corresponding to the N-type well 701 is formed of P-type, and a well corresponding to the P-type well 601 is formed of N-type.

  As described above, according to the present embodiment, the change in the output from each light receiving element due to the change in the amount of received light (irradiance unevenness) according to the light receiving position generated by the imaging optical system and the secondary imaging lens, that is, A light receiving element having a structure in which nonuniformity of sensitivity distribution is reduced can be realized.

  In the above embodiment, the case where the light receiving element for light source detection is provided in the focus detection unit has been described. However, the imaging optical for light source detection is provided outside the focus detection unit (for example, around the pentaprism 4). A system and a light receiving element may be provided.

The figure explaining arrangement | positioning of the light receiving element of the sensor unit in Example 1 of this invention. 2 is a diagram illustrating a configuration of a focus detection optical system (re-imaging optical system) in Embodiment 1. FIG. The figure which shows the example for the illuminance part on the light receiving element for light source detection in an Example. The figure explaining the position on the light receiving element for light source detection in an Example. FIG. 3 is a diagram illustrating a light source detection light-receiving element according to the first embodiment. The figure explaining the light receiving element for light source detection in Example 2 of this invention. The figure explaining the structure of the light receiving element for light source detection in Example 3 of this invention. FIG. 6 is a schematic diagram illustrating a structure of a light receiving element for detecting a light source according to Example 3. 1 is a diagram illustrating an imaging system including an imaging device and an interchangeable lens according to an embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Single-lens reflex camera 7 Photometric sensor 11 Interchangeable lens 12 Focus lens 25 Focus detection unit 26 Secondary imaging lens unit 29 Sensor unit 30 Camera microcomputer 101a-103a, 101b-103b Light receiving element array 104a-107a, 104b for focus detection ˜107b Light receiving element for detecting light source 110 Shielding mask 201a to 203b Secondary imaging lens 215 Exit pupil of imaging optical system 601 P type well 701 N type well

Claims (3)

A pair of imaging optical systems for imaging a light beam from the imaging optical system , each of which includes a plurality of pixels and outputs a signal for detecting a focus state of the imaging optical system, the spectral sensitivity characteristics being equal to each other A pair of imaging optical systems for guiding a light beam to the first light receiving element ;
A pair of light receiving elements that receive light beams from the pair of imaging optical systems and have different spectral sensitivity characteristics , and a pair of second light receiving elements disposed in the vicinity of each of the first light receiving elements ;
Anda detection means for detecting relates to a light source based on an output from the pair of second light receiving elements,
Each of the second light receiving elements is a light shielding member for reducing a change in output accompanying a change in the amount of received light according to a light receiving position generated by the imaging optical system and the imaging optical system . Each light receiving element has a light shielding member that does not have,
The light blocking member, the amount of light received at the second respective light receiving elements, as no low position Te direction of each odor perpendicular to the base length direction and said direction, characterized in that it has a shape shielding area becomes smaller An imaging device. A pair of imaging optical systems for imaging a light beam from the imaging optical system , each of which includes a plurality of pixels and outputs a signal for detecting a focus state of the imaging optical system, the spectral sensitivity characteristics being equal to each other A pair of imaging optical systems for guiding a light beam to the first light receiving element ;
A pair of light receiving elements that receive light beams from the pair of imaging optical systems and have different spectral sensitivity characteristics , and a pair of second light receiving elements disposed in the vicinity of each of the first light receiving elements ;
Anda detection means for detecting relates to a light source based on an output from the pair of second light receiving elements,
Each of the second light receiving elements has a light receiving portion shape for reducing a change in output accompanying a change in the amount of received light according to a light receiving position generated by the imaging optical system and the imaging optical system , Each light receiving element has a light receiving portion shape that does not have,
The light receiving unit shape, wherein the amount of light received at the second respective light receiving elements, as no low position Te direction of each odor perpendicular to the base length direction and the direction, the light receiving portion shape der light receiving area is increased An imaging device characterized by that. On the basis of the detection result for the pair of the first light source and the output of the light receiving element or these imaging apparatus according to claim 1 or 2, characterized in that the focus control of the imaging optical system.