JP2010072193A - Signal generator, and imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a signal generator and an imaging device for reducing an electric power consumption and reducing a chip area, while maintaining high range-finding accuracy. <P>SOLUTION: One shift register is shared in a first pixel row and the second pixel row, by arranging the first and second pixel rows comprising a plurality of photoelectric transfer elements for accumulating a signal charge in response to an incident light amount, in parallel, while shifted relatively in the direction of arranging the photoelectric transfer elements, and by arranging a storage part for holding a charge generated in each photoelectric transfer element and the shift register for transferring the charge, between the first and second pixel rows. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a signal generation device that generates a focus detection signal. The present invention also relates to an imaging device having the signal generation device.

  A phase difference detection method is known as one of focus detection methods used in autofocus cameras. In the phase difference detection method, light beams at the same point on the primary imaging equivalent surface of the imaging optical system are split by the pupil splitting optical system. The divided light flux is incident on a pair of pixel columns composed of a plurality of light receiving elements, and is detected in each pixel column as a subject image. From the two image interval values of the detected subject image, the focus state at the distance measuring point arranged in the imaging screen is detected. The accuracy of focus detection is determined by the distance and pixel width between a pair of pixel columns (a reference portion and a reference portion). If the distance between the pixel columns is increased in order to improve the accuracy of focus detection, the chip size is increased. On the other hand, the minimum pixel width is limited by the pixel manufacturing technology.

As a method for improving the accuracy of focus detection without changing the distance between pixel columns or the pixel width, a method described in Patent Document 1 is known. In Patent Document 1, two line sensors having the same shape as one line sensor are shifted in the pixel width direction by a distance half the pixel width. The signals from the pixels that are shifted in position are sequentially transferred by a shift register provided for each line sensor, and distance measurement is performed using the signals, thereby improving the focus state detection accuracy to 2 It is improved by a factor of ^1/2 .
JP 2006-285080 A

  However, in Patent Document 1, although the focus detection accuracy is improved, one shift register is required corresponding to one pixel column, and all the shift registers are always operated. Power consumption is tripled, and the chip becomes larger by the area of the shift register.

  The present invention has been made in view of the above-described problems, and provides a signal generation device and an imaging device capable of reducing power consumption and reducing the chip area while maintaining high distance measurement accuracy. For the purpose.

  The present invention has been made to solve the above-described problem, and is a first light-receiving unit that is arranged in a first dimension in a first direction and includes a plurality of photoelectric conversion elements that accumulate signal charges according to the amount of incident light. (Corresponding to the upper light receiving unit 100 in FIG. 1) and a plurality of the photoelectric conversion elements arranged one-dimensionally in the first direction, and in the second direction intersecting the first direction, A second light receiving portion (lower light receiving portion in FIG. 1) arranged with a predetermined distance from one light receiving portion and shifted by a predetermined amount in the first direction from the first light receiving portion. And a first charge holding unit (corresponding to the upper storage unit 102 in FIG. 1) that is provided corresponding to the first light receiving unit and holds the signal charge accumulated in the photoelectric conversion element. ), And corresponding to the second light receiving portion, and accumulated by the photoelectric conversion element The first charge is disposed between a second charge holding unit (corresponding to the lower storage unit 112 in FIG. 1) that holds the signal charge, the first light receiving unit, and the second light receiving unit. A charge transfer unit (corresponding to the shift register 12 in FIG. 1) for transferring the signal charge held in the holding unit and the second charge holding unit to the output side; and the signal charge transferred from the charge transfer unit. It is a signal generator characterized by having a conversion part (corresponding to FDA (Floating Diffusion Amplifier) 13 in FIG. 1) for converting into a voltage signal for focus detection.

  In addition, the signal generation device of the present invention has a plurality of settable operation sequences, and the first light receiving unit corresponding to each of the first light receiving unit and the second light receiving unit according to the set operation sequence. Transfer of the signal charge to the charge holding unit and the second charge holding unit; and transfer of the signal charge from each of the first charge holding unit and the second charge holding unit to the charge transfer unit; And a control unit (corresponding to the control unit 3 in FIG. 1) for controlling the transfer of the signal charges in the charge transfer unit.

  Further, the signal generation device of the present invention is configured such that, as the settable operation sequence, all of the light receiving portions of one of the signal charges of the first light receiving portion and the second light receiving portion accumulated in the same period. It has an operation sequence (corresponding to FIG. 3) in which the signal charges are transferred to the charge transfer unit and then all the signal charges of the other light receiving unit are transferred to the charge transfer unit.

  In the signal generating device of the present invention, as the settable operation sequence, the signal charge stored in the second light receiving unit is stored while the signal charge is stored in the first light receiving unit. An operation sequence for transferring the signal charge stored in the first light receiving unit to the charge transfer unit while transferring the signal charge to the charge transfer unit and storing the signal charge in the second light receiving unit ( (Corresponding to FIG. 4).

  In the signal generating device of the present invention, as the settable operation sequence, all the signal charges of the first light receiving unit and the second light receiving unit accumulated in the same period are simultaneously transferred to the charge transfer unit. And an operation sequence (corresponding to FIG. 5).

  The present invention also includes an image sensor (corresponding to the image sensor 509 in FIG. 6), an optical system (corresponding to the focus lens 400 in FIG. 6) for causing light from a subject to enter the image sensor, and claims 1 to 10. 6. The signal generation device according to any one of items 5 (corresponding to the AF sensor 510 and the control unit 513 in FIG. 6) and a signal processing unit that processes the voltage signal output from the signal generation device (the focus calculation unit in FIG. 6). 511, corresponding to the lens drive signal generation unit 512), a drive unit (corresponding to the lens drive unit 401 in FIG. 6) that moves the optical system according to the processing result of the signal processing unit and adjusts the focal position, It is an imaging device characterized by having.

  In the above description, the description in parentheses is for the purpose of associating the embodiment of the present invention described later with the components of the present invention for convenience, and the contents of the present invention are not limited by this description. Absent.

  According to the present invention, since the first light receiving unit and the second light receiving unit are arranged with a predetermined amount shifted in the first direction, high ranging accuracy can be maintained. In addition, since a common charge transfer unit is arranged for both the first light receiving unit and the second light receiving unit, compared to the case where individual charge transfer units are arranged for each light receiving unit, Power consumption can be reduced and the chip area can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration of a signal generation device according to an embodiment of the present invention. This signal generator shows an example of a CCD (Charge Coupled Device) image sensor and its control circuit used for a distance measuring sensor of a camera. As shown in FIG. 1, the signal generation device includes an imaging unit 1 having an upper pixel column 10, a lower pixel column 11, a shift register 12, and an FDA 13, a sequence setting unit 2, and a control unit 3. ing.

  The upper pixel column 10 includes an upper light receiving unit 100, an upper storage gate unit 101, an upper storage unit 102, and an upper transfer gate unit 103. The lower pixel column 11 includes a lower light receiving unit 110, a lower accumulation gate unit 111, a lower storage unit 112, and a lower transfer gate unit 113. Here, for simplification of description, the upper light receiving unit 100 and the lower light receiving unit 110 are collectively referred to as a light receiving unit, and the upper storage gate unit 101 and the lower storage gate unit 111 are collectively referred to as a storage gate unit, The upper storage unit 102 and the lower storage unit 112 are collectively referred to as a storage unit, and the upper transfer gate unit 103 and the lower transfer gate unit 113 are collectively referred to as a transfer gate unit.

  The imaging unit 1 converts an incident optical signal into an electrical signal and outputs it. Conversion from the optical signal to the electric signal is performed by the light receiving unit. The light receiving unit is composed of a plurality of divided photoelectric conversion elements. This divided photoelectric conversion element is called a pixel, and one divided pixel is defined as one pixel. The light receiving unit is divided for each group of a plurality of pixels. The group of pixels is referred to as a pixel column, and one pixel column is defined as one pixel column.

  The upper pixel column 10 and the lower pixel column 11 have the same configuration, and a plurality of photoelectric conversion elements are arranged one-dimensionally in the first direction (horizontal direction in FIG. 1) in the light receiving section in each pixel column. It has been. The upper pixel column 10 and the lower pixel column 11 are arranged with a predetermined interval in the second direction (vertical direction in FIG. 1). A signal charge corresponding to the amount of incident light is accumulated in each photoelectric conversion element constituting the light receiving unit in the upper pixel column 10 and the lower pixel column 11. The lower pixel column 11 is arranged so as to be shifted in the first direction by a distance that is half the pixel width with respect to the upper pixel column 10 and inverted upside down. Hereinafter, this pixel arrangement is referred to as a staggered pixel arrangement.

  The accumulation gate unit, the storage unit, and the transfer gate unit are each composed of a plurality of accumulation gates, storage units, and transfer gates divided for each pixel in the same manner as the light receiving unit, one for each pixel. Each storage gate, storage, and transfer gate is provided. A set of pixels, storage gates, storage and transfer gates are arranged along the shift register 12, and the shift register 12 is arranged so as to be sandwiched between the upper pixel column 10 and the lower pixel column 11. Is connected to the pixels having the same pixel number in the upper pixel column 10 and the lower pixel column 11. The signal charge generated in the pixel is transferred in the order of the accumulation gate, storage, transfer gate, and shift register 12. The output terminal of the shift register 12 is connected to the FDA 13, and the signal charges sequentially transferred are output as a voltage signal Vout by the FDA 13.

  The sequence setting unit 2 generates a control signal mode that changes the timing at which the control unit 3 generates various control signals. The generated control signal mode is input to the control unit 3.

The control unit 3 receives the control signal mode from the sequence setting unit 2 and generates control signals phi, TG1 _U , TG2 _U , rs _U , TG1 _L , TG2 _L , and rs _L. The control signal phi generated by the control unit 3 is input to the shift register 12, the control signal TG1 _U is input to the upper storage gate unit 101, the control signal TG2 _U is input to the upper transfer gate unit 103, and the control signal rs _U Is input to the upper storage unit 102, the control signal TG1 _L is input to the lower storage gate unit 111, the control signal TG2 _L is input to the lower transfer gate unit 113, and the control signal rs _L is input to the lower storage unit 112. Entered.

The control signal phi is a control signal for sequentially transferring charges on the shift register 12. The control signal TG 1 _U is a control signal for transferring the charge accumulated in the upper light receiving unit 100 to the upper storage unit 102. The control signal TG1 _L is a control signal for transferring the charge accumulated in the lower light receiving unit 110 to the lower storage unit 112. Control signal TG2 _U is a control signal for transferring the charge stored in the upper storage portion 102 to the shift register 12. The control signal TG2 _L is a control signal for transferring the charge accumulated in the lower storage unit 112 to the shift register 12. The control signal rs _U is a control signal that resets the charge of the upper storage unit 102. The control signal rs _L is a control signal that resets the charge in the lower storage unit 112.

With the above-described configuration, it is possible to read out signals of two pixel columns with one shift register. As a result, the chip area can be reduced by the shift register and the power consumption can be reduced while maintaining the focal position detection accuracy at ^21/2 times.

Next, the operation of the signal generator configured as described above will be described. FIG. 2 shows the relationship among the operation mode, control signal, and voltage signal for one pixel column. In FIG. 2, for simplification of description, the control signals TG1 _U and TG1 _L are represented by the control signal TG1, the control signals TG2 _U and TG2 _L are represented by the control signal TG2, and the control signals rs _U and rs _L are controlled. This is represented by signal rs. In FIG. 2, the operation modes, V _out , phi, rs, TG1, and TG2 are arranged in this order from the top.

  In the setting mode, accumulation conditions and readout conditions are set. When the accumulation condition and the read condition are set, the operation mode shifts to the accumulation mode. In the accumulation mode, charges generated according to the amount of irradiation light are accumulated in the light receiving unit. Before the start of accumulation, the control signals TG1, TG2, and rs are set to L level. In the accumulation mode, first, when the control signal TG1 becomes H level for a certain period, the charge accumulated in the light receiving portion moves to the storage portion through the accumulation gate portion, and the charge in the light receiving portion becomes empty. In addition, the control signal rs simultaneously becomes H level, and the charge in the storage unit is reset. Thereby, at the start of accumulation, no charge is accumulated in the light receiving unit and the storage unit. In this state, when the control signal TG1 becomes L level, the light receiving unit is in an accumulation state, and charge accumulation is started.

  When the control signal rs becomes L level during charge accumulation, the storage unit enters a charge holding state. When the light receiving unit accumulates a certain amount of charge or when the accumulation time reaches a certain time, the control signal TG1 becomes H level for a certain period, and the charge accumulated in the light receiving unit moves to the storage unit. Thereby, the electric charge accumulated in each pixel is held in the storage unit corresponding to each pixel, and the accumulation is completed.

When the accumulation mode ends, the mode shifts to the charge transfer mode. Just before the start of the charge transfer mode, the control signal TG2 becomes H level for a certain period, and the charge held in the storage unit is transferred to the shift register 12. The charges transferred to the shift register 12 are sequentially transferred toward the FDA 13 in synchronization with the control signal phi in the charge transfer mode. The charge transferred by the shift register 12 is converted into a signal voltage V _out by FDA13, is output.

  When the above-described pixel column operates as a phase difference type distance measuring sensor, the pixel column is physically separated from each other, and is a pair of pixel columns that optically receive light from the same point. However, since the configuration and control are exactly the same in this embodiment, they are omitted.

  Next, operations of the high-precision ranging operation sequence, the continuous ranging operation sequence, and the high-speed ranging operation sequence will be described with reference to FIGS. Note that the relationship between the circuit operation and the control signal is the same as that described with reference to FIG. The circuit operation sequence is set by the control signal mode from the sequence setting unit 2, but is not shown in FIGS. 3 to 5.

FIG. 3 shows control signals and output waveforms in the high-precision distance measuring operation sequence. In FIG. 3, V _out , upper pixel column operation mode, lower pixel column operation mode, rs _U , TG 1 _U , TG 2 _U , rs _L , TG 1 _L , and TG 2 _L are arranged in this order from the top. In the high-precision distance measuring operation sequence, the same accumulation control is performed on the upper pixel column 10 and the lower pixel column 11, and the readout control with different readout start timings is performed.

As an operation sequence of the circuit, first, the same accumulation condition is set for all the pixel columns in the setting mode. Thereafter, the operation mode shifts to the accumulation mode, and all pixel columns start accumulation all at once. At the end of the accumulation mode, the control signals TG1 _U and TG1 _L temporarily become H level simultaneously. As a result, all charges in the light receiving unit are transferred to the storage unit, and the accumulation mode ends. Subsequently, the control signal TG2 _U temporarily becomes H level, the charge of the upper pixel row 10 is transferred to the shift register 12, sequentially in synchronism with the control signal phi, is output as the output voltage V _out.

When the signal of the upper pixel column 10 has been transferred, the control signal TG2 _L temporarily becomes H level, the charge of the lower pixel column 11 is transferred to the shift register 12, and sequentially in synchronization with the control signal phi. _Is output as the output voltage V _out . Therefore, the imaging unit 1 outputs a voltage signal _Vout obtained by converting the charge accumulated by exposure for the same time for the same subject. By performing distance measurement on the voltage signal _Vout obtained in this way, the focus position detection accuracy is 2 ¹ compared to the case where only the upper pixel column 10 or only the lower pixel column 11 is used. ^{/ 2} times. The above high-precision distance measuring operation sequence is suitable for imaging a subject (such as a stationary object) that does not move or moves little.

FIG. 4 shows control signals and output waveforms in a continuous ranging operation sequence in which accumulation and readout are alternately performed in the upper pixel column 10 and the lower pixel column 11. In FIG. 4, V _out , upper pixel column operation mode, lower pixel column operation mode, rs _U , TG1 _U , TG2 _U , rs _L , TG1 _L , TG2 _L are arranged in this order from the top. In the continuous ranging operation sequence, accumulation control and readout control are performed separately for the upper pixel column 10 and the lower pixel column 11.

As an operation sequence of the circuit, first, the upper pixel column 10 is set to a setting mode, and accumulation conditions and readout conditions are set. At this time, although the lower pixel column 11 is in the charge transfer mode, no effective output can be obtained because accumulation has not yet been performed. Subsequently, the upper pixel row 10 shifts to the accumulation mode and starts accumulation. When the accumulation of the upper pixel column 10 is finished, the control signal TG1 _U becomes H level. As a result, all charges in the upper light receiving unit 100 are transferred to the upper storage unit 102.

When the accumulation time of the upper pixel column 10 is longer than the time for reading all the pixels of the lower pixel column 11, the control signal TG1 _U becomes L level and the control signal TG2 _U becomes H level at the same time. Further, when the accumulation time of the upper pixel column 10 is shorter than the time for reading all the pixels of the lower pixel column 11, the time necessary for reading all the pixels of the lower pixel column 11 has elapsed. The control signal TG2 _U becomes H level.

When the control signal TG2 _U becomes H level, the charge of the upper storage portion 102 is transferred to the shift register 12, the upper pixel row 10 is shifted to the charge transfer mode. When the upper pixel column 10 enters the charge transfer mode, the lower pixel column 11 shifts to the setting mode, and accumulation conditions and readout conditions are set. Thereafter, the lower pixel column 11 shifts to the accumulation mode and starts accumulation. When the accumulation of the lower pixel column 11 is completed, the control signal TG1 _L becomes H level. As a result, all charges in the lower light receiving unit 110 are transferred to the lower storage unit 112.

When the accumulation time of the lower pixel column 11 is longer than the time for reading all the pixels of the upper pixel column 10, the control signal TG1 _L becomes L level and the control signal TG2 _L becomes H level at the same time. In addition, when the accumulation time of the lower pixel column is shorter than the time for reading all the pixels of the upper pixel column, the control signal TG2 _L becomes H level after the time for reading all the pixels of the upper pixel column 10 has elapsed. Become.

When the control signal TG2 _L becomes H level, the charge in the lower storage unit 112 is transferred to the shift register 12, and the lower pixel column 11 shifts to the charge transfer mode. Here, when the signal readout for all the pixels of the upper pixel column 10 is completed, the upper pixel column 10 that has been previously shifted to the charge transfer mode is shifted to the setting mode again, and the accumulation condition and the readout condition are set. After that, the storage mode is entered. When the accumulation mode ends, the upper pixel column 10 shifts to the charge transfer mode, and when the signal readout for all the pixels in the upper pixel column 10 ends, the sequence shifts to the setting mode again. The lower pixel column 11 repeats the same sequence.

  By such an operation, the upper pixel column 10 and the lower pixel column 11 perform the accumulation mode and the charge transfer mode in a reversed manner, and output distance measurement information from the subject at a period shifted by a certain period. The above-mentioned continuous ranging operation sequence is suitable when moving object prediction is used for a subject moving at a constant speed.

FIG. 5 shows control signals and output waveforms in a high-speed ranging operation sequence in which the upper pixel column 10 and the lower pixel column 11 are combined and used as one pixel. In FIG. 5, V _out , upper pixel column operation mode, lower pixel column operation mode, rs _U , TG 1 _U , TG 2 _U , rs _L , TG 1 _L and TG 2 _L are arranged in this order. In the high-speed ranging operation sequence, the same accumulation control and readout control are performed on the upper pixel column 10 and the lower pixel column 11.

As an operation sequence of the circuit, first, the same accumulation condition and readout condition are set for the upper pixel column 10 and the lower pixel column 11 in the setting mode. Thereafter, the operation mode shifts to the accumulation mode, and all pixel columns start accumulation all at once. The accumulation mode is completed in half the time compared to other operation sequences, and the control signals TG1 _U and TG1 _L simultaneously become H level. Thereby, all the charges in the light receiving unit are transferred to the storage unit.

Thereafter, the control signals TG1 _U and TG1 _L again become L level, and at the same time, the control signals TG2 _U and TG2 _L become H level, and the charge in the storage unit is transferred to the shift register 12. Accordingly, the charges having the same pixel numbers in the upper pixel column 10 and the lower pixel column 11 are added to the shift register 12 and transferred. When charges are transferred to the shift register 12, the operation mode shifts to the charge transfer mode. The charge transfer mode time is half that of the case where the upper pixel column 10 and the lower pixel column 11 are read in order because charges are already added in the shift register 12.

  The above high-speed ranging operation sequence is suitable for imaging a subject (such as figure skating) that is difficult to predict a moving object or for capturing a dark subject.

  Next, a camera (imaging device) having the above signal generation device will be described. FIG. 6 shows a configuration related to detection of the focus state, among the cameras. The camera shown in FIG. 6 is a single-lens reflex camera, and includes a lens unit 4 including a focus lens 400 and a lens driving unit 401, a main mirror 500, a sub mirror 501, a screen 502, a pentaprism 503, an eyepiece 504, and a condenser. The camera body 5 includes a lens 505, a fixed mirror 506, a pupil division diaphragm 507, a pupil division lens 508, an image sensor 509, an AF sensor 510, a focus calculation unit 511, a lens drive signal generation unit 512, and a control unit 513. ing. The lens unit 4 is configured to be detachable from the camera body 5 via a camera mount (not shown) provided on the front surface of the camera body 5. Here, the actual imaging optical system is composed of a plurality of lenses, but FIG. 6 shows only the focus lens 400 that is a focus adjusting lens included in the imaging optical system.

  The focus lens 400 collects a light beam from a subject (not shown) and makes it enter the camera. The main mirror 500 is a mirror having a central portion formed of a half mirror, and reflects and transmits a light beam incident through the focus lens 400. Here, the main mirror 500 is configured to be rotatable by a mirror driving mechanism (not shown). When the main mirror 500 is at the position shown in FIG. 6, the main mirror 500 reflects a part of the light beam incident through the focus lens 400 to the screen 502 side and transmits a part to the sub mirror 501 side. . On the other hand, when the main mirror 500 moves due to the rotation and is parallel to the screen 502, the light beam incident through the focus lens 400 enters the image sensor 509.

  The screen 502 is disposed on the primary imaging equivalent surface of the imaging optical system, and forms a light beam reflected by the main mirror 500 toward the screen 502 as a subject image. The pentaprism 503 makes an object image obtained by the screen 502 an erect image and then enters the eyepiece 504. The eyepiece 504 enlarges the subject image from the pentaprism 503 to a size that can be viewed by the photographer.

  The sub mirror 501 is provided on the back side of the central portion of the main mirror 500 and reflects the light beam transmitted through the main mirror 500 toward the condenser lens 505. The condenser lens 505 collects the subject light reflected by the sub mirror 501 and imaged on the primary imaging equivalent surface 514. The fixed mirror 506 reflects the subject light collected by the condenser lens 505 in the direction of the pupil division diaphragm 507. The pupil division diaphragm 507 divides the subject light reflected by the fixed mirror 506 into pupils. The pupil division lens 508 collects the light beam divided by the pupil division diaphragm 507 and makes it incident on a predetermined area of the AF sensor 510.

  The AF sensor 510 is composed of at least a pair of light receiving portions provided corresponding to the distance measuring points. The AF sensor 510 corresponds to the imaging unit 1 in FIG. The AF sensor 510 photoelectrically converts the subject image, converts a charge signal obtained by the photoelectric conversion into a voltage signal, and outputs the voltage signal to the focus calculation unit 511. The control unit 513 outputs a control signal to the AF sensor 510 and controls the operation of the AF sensor 510. The control unit 513 corresponds to the control unit 3 in FIG.

  The focus calculation unit 511 calculates, from the voltage signal indicating the subject image output as a pair from the AF sensor 510, a two-image interval value in the subject image respectively incident on the pair of light receiving units by, for example, correlation calculation. The lens drive signal generation unit 512 generates a lens drive signal for moving the focus lens 400 to the in-focus position from the two-image interval value calculated by the focus calculation unit 511 and outputs the lens drive signal to the lens drive unit 401. The lens driving unit 401 drives the focus lens 400 in the optical axis direction (the direction of arrow A in FIG. 6) in accordance with the lens driving signal from the lens driving signal generation unit 512. The image sensor 509 photoelectrically converts a light beam from a subject to obtain an image signal for recording or display.

  FIG. 7 schematically shows a secondary imaging optical system used in the camera of FIG. The secondary imaging optical system includes the condenser lens 505, the pupil division diaphragm 507, and the pupil division lens 508 shown in FIG. In FIG. 7, the fixed mirror 506 shown in FIG. 6 is omitted. The luminous flux of the subject imaged on the primary imaging equivalent surface 514 is collected by the condenser lens 505 and is pupil-divided by the pupil division diaphragm 507. The pupil-divided light beam is collected by the pupil-dividing lens 508 and imaged on a predetermined area of the AF sensor 510 having the standard pixel row 510a and the reference pixel row 510b. In FIG. 7, a pair of pupil division lenses is provided for the pair of light receiving units.

  As described above, according to the present embodiment, in the signal generation device having the staggered pixel arrangement, the shift register 12 is arranged between the upper pixel column 10 and the lower pixel column 11 and shared, thereby reducing the chip area. The power consumption can be reduced as compared with the conventional example. In addition, according to the present embodiment, three operation sequences having different characteristics can be realized, and these three operation sequences can be selected according to the purpose.

In the high-accuracy ranging operation sequence, the focus detection accuracy is 2 ^1/2 compared to the case where only the upper pixel column 10 or only the lower pixel column 11 is used by using the ranging information of the staggered pixel arrangement. Can be doubled. In the continuous ranging operation sequence, the upper pixel column 10 and the lower pixel column 11 are switched between the accumulation mode and the charge transfer mode, so that only the upper pixel column 10 or only the lower pixel column 11 is used. Thus, ranging information can be obtained twice as often. In the high-speed distance measuring operation sequence, the charges of the upper pixel column 10 and the lower pixel column 11 are transferred together by the shift register 12, so that both the accumulation time and the readout time can be shortened.

  As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to the above-described embodiments, and includes design changes and the like without departing from the gist of the present invention. .

It is a block diagram which shows the structure of the signal generation apparatus by one Embodiment of this invention. It is a timing chart which shows operation | movement of the signal generation apparatus by one Embodiment of this invention. It is a timing chart which shows operation | movement (high-precision ranging operation sequence) of the signal generation apparatus by one Embodiment of this invention. It is a timing chart which shows the operation | movement (continuous ranging operation sequence) of the signal generation apparatus by one Embodiment of this invention. It is a timing chart which shows the operation | movement (high-speed ranging operation sequence) of the signal generation apparatus by one Embodiment of this invention. It is a block diagram which shows the structure of the camera by one Embodiment of this invention. It is a schematic diagram which shows the structure of the secondary imaging optical system used for the camera by one Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Imaging part, 2 ... Sequence setting part, 3 ... Control part, 4 ... Lens unit, 5 ... Camera body, 10 ... Upper pixel row, 11 ... Lower side Pixel row, 12 ... shift register, 13 ... FDA, 100 ... upper light receiving portion, 101 ... upper storage gate portion, 102 ... upper storage portion, 103 ... upper transfer gate portion, DESCRIPTION OF SYMBOLS 110 ... Lower light-receiving part, 111 ... Lower storage gate part, 112 ... Lower storage part, 113 ... Lower transfer gate part, 400 ... Focus lens, 401 ... Lens Drive unit, 500 ... main mirror, 501 ... sub mirror, 502 ... screen, 503 ... pentaprism, 504 ... eyepiece, 505 ... condenser lens, 506 ... fixed mirror, 507 ... Pupil Throttle split, 508 ... pupil division lens, 509 ... imaging element, 510 ... AF sensor, 511 ... focus calculation unit, 512 ... lens driving signal generation unit, 513 ... control unit

Claims (6)

A first light-receiving unit that is arranged in a first direction in a first direction and includes a plurality of photoelectric conversion elements that accumulate signal charges according to the amount of incident light;
The plurality of photoelectric conversion elements arranged one-dimensionally in the first direction, and arranged at a predetermined interval from the first light receiving unit in a second direction intersecting the first direction In addition, the first light receiving unit and the second light receiving unit arranged by shifting a predetermined amount in the first direction,
A first charge holding unit provided corresponding to the first light receiving unit and holding the signal charge accumulated in the photoelectric conversion element;
A second charge holding unit that is provided corresponding to the second light receiving unit and holds the signal charge accumulated in the photoelectric conversion element;
A charge transfer unit that is arranged between the first light receiving unit and the second light receiving unit and transfers the signal charge held in the first charge holding unit and the second charge holding unit to the output side. When,
A conversion unit that converts the signal charge transferred from the charge transfer unit into a voltage signal for focus detection;
A signal generation device comprising:   There are a plurality of settable operation sequences, and the first charge holding unit and the second charge holding corresponding to each of the first light receiving unit and the second light receiving unit according to the set operation sequence Transfer of the signal charge to a part, transfer of the signal charge from each of the first charge holding part and the second charge holding part to the charge transfer part, and transfer of the signal charge in the charge transfer part The signal generation apparatus according to claim 1, further comprising a control unit that controls each of the transfer.   As the settable operation sequence, all the signal charges of one light receiving unit among the signal charges of the first light receiving unit and the second light receiving unit accumulated in the same period are transferred to the charge transfer unit. 3. The signal generation device according to claim 2, further comprising an operation sequence for transferring all the signal charges of the other light receiving unit to the charge transfer unit.   As the settable operation sequence, the signal charge stored in the second light receiving unit is transferred to the charge transfer unit while the signal charge is stored in the first light receiving unit, and the first 3. The operation sequence of transferring the signal charge stored in the first light receiving unit to the charge transfer unit while the signal charge is stored in a second light receiving unit. The signal generation device described.   The settable operation sequence includes an operation sequence for simultaneously transferring all the signal charges of the first light receiving unit and the second light receiving unit accumulated in the same period to the charge transfer unit. The signal generation device according to claim 2. An image sensor;
An optical system for allowing light from a subject to enter the image sensor;
A signal generation device according to any one of claims 1 to 5,
A signal processing unit for processing a voltage signal output from the signal generating device;
A drive unit that moves the optical system according to a processing result of the signal processing unit and adjusts a focal position;
An imaging device comprising:

Images