JP6214596B2 - Driving method of imaging apparatus - Google Patents

Description

  The present invention relates to an imaging apparatus driving method, and more particularly to an imaging apparatus driving method capable of performing focus detection on an imaging surface.

  In recent years, the development of imaging devices has been remarkable. An apparatus that performs pupil division type focus detection using an image sensor in which a microlens is formed in each pixel of an imaging apparatus is known (Patent Document 1).

  According to Patent Document 1, the image sensor is arranged on the planned imaging plane of the photographing lens. In addition, one pixel of the image sensor includes a photoelectric conversion element A and a photoelectric conversion element B, and each photoelectric conversion element is substantially conjugate with the pupil of the photographing lens by the microlens of the image sensor formed on the photographing lens side. It is arranged to be.

  Here, the photoelectric conversion element A receives a light beam that passes through a part of the pupil of the photographing lens. Further, the photoelectric conversion element B receives a light beam transmitted through a portion different from the pupil transmitted by the photoelectric conversion element A. At the time of focus detection, signals are read independently from the photoelectric conversion elements A and B of a plurality of pixels, and two images are generated by light beams transmitted through different positions of the pupil of the photographing lens. Further, the image information can be obtained by adding the two photoelectric conversion elements A and B.

JP 2001-124984 A

  However, in Patent Document 1, since the signals of the photoelectric conversion element A and the photoelectric conversion element B are sequentially and independently read, the light reception times of the signal of the photoelectric conversion element A and the signal of the photoelectric conversion element B are different.

  Specifically, when reading a signal in a certain row, first, a reset signal of the photoelectric conversion element A is output. Next, the signal of the photoelectric conversion element A is output. Similarly, a reset signal for the photoelectric conversion element B is output, and then an image signal for the photoelectric conversion element B is output. By this operation, a time difference of several tens to several hundreds μsec occurs in the signals of the photoelectric conversion element A and the photoelectric conversion element B. As a result, an error occurs between the signals of the photoelectric conversion element A and the photoelectric conversion element B, and it is difficult to improve the accuracy of focus detection.

In view of the above problems, the present invention amplifies signals of the plurality of photoelectric conversion elements, each of which is shared by the plurality of photoelectric conversion units each having a plurality of photoelectric conversion elements, and each of the plurality of photoelectric conversion elements of the photoelectric conversion unit. A plurality of amplifying units, a plurality of common output lines from which signals of the plurality of amplifying units are output, a plurality of column circuits receiving signals from any of the plurality of common output lines, and the plurality of column circuits And a horizontal output line for outputting a signal processed in step (b) , wherein the signal of at least one of the plurality of photoelectric conversion elements of the photoelectric conversion unit is input to the amplification unit. A signal for focus detection is generated by a first operation of reading to a node and reading a signal to the common output line via the amplifier, and the signal read by the first operation is input to the amplifier. Image formation by the second operation of reading the signal of another photoelectric conversion element included in the same photoelectric conversion unit in the held state to the input node of the amplifying unit and reading the signal to the common output line via the amplifying unit The focus detection signals and the image formation signals generated in the plurality of photoelectric conversion units in a predetermined row, which are generated in the plurality of column circuits, are collected in a horizontal output line. It is output to and said Rukoto.

  According to the present invention, the accuracy of focus detection is improved.

1 is an overall block diagram of a first embodiment of an imaging apparatus according to the present invention. Timing chart of the first embodiment of the imaging apparatus according to the present invention Overall block diagram of a second embodiment of the imaging apparatus according to the present invention Timing chart in the second embodiment of the imaging apparatus according to the present invention Pixel block diagram in the second embodiment of the imaging apparatus according to the present invention Timing chart in the third embodiment of the imaging apparatus according to the present invention Pixel block diagram in the second embodiment of the imaging apparatus according to the present invention Timing chart in the third embodiment of the imaging apparatus according to the present invention

  Embodiments of the present invention will be described with reference to the drawings. In the following description, an example in which a pixel is configured with an N-channel MOS transistor will be described. The present invention can also be applied to the case where the pixel is formed of a P-channel MOS transistor. In this case, the voltage or the like may be changed as appropriate.

Example 1
FIG. 1 is an equivalent circuit diagram of the image pickup apparatus of the present embodiment. The photoelectric conversion unit 100 includes a plurality of photoelectric conversion elements, and here includes a first photoelectric conversion element 101A and a second photoelectric conversion element 101B. A photodiode can be used as the photoelectric conversion element.

  The transfer transistors 102A and 102B are provided corresponding to each of the plurality of photoelectric conversion elements, and transfer the signals of the corresponding photoelectric conversion elements to the input node 103 of the amplification unit. A lens array (not shown) having a plurality of lenses arranged corresponding to each of the plurality of photoelectric conversion units is arranged above the photoelectric conversion element. Each lens of the lens array focuses on a plurality of photoelectric conversion elements of the same photoelectric conversion unit. The plurality of photoelectric conversion elements included in each photoelectric conversion unit are arranged at different positions in plan view.

  The amplifying unit 104 amplifies the signal transferred to the input node 103 and outputs the amplified signal to the common output line 107. For the amplifying unit 104, a MOS transistor can be used.

  The reset transistor 105 supplies a reset voltage to the input node 103 of the amplification unit. The selection transistor 106 controls electrical conduction between the amplification unit 104 and the common output line 107.

  A current source 108 is electrically connected to the common output line 107. The current source 108 supplies a bias current to the amplification unit 104, and the amplification unit 104 and the current source 108 constitute a source follower.

  Drive lines 109A and 109B, a drive line 110, and a drive line 111 are connected to the gates of the transfer transistors 102A and 102B, the reset transistor 105, and the selection transistor 106, respectively. A driving pulse from the vertical scanning circuit 112 is sequentially or randomly supplied to each gate for each row.

  The column circuit receives a signal from the common output line 107. The column circuit is connected to the common output line directly or via a switch. The signals processed in the column circuit are sequentially output to the output amplifier 115 by the horizontal scanning circuit 114 and output to the outside.

  The main operation of the column circuit is to invert and amplify the signal of the common output line 107 with a gain determined by the capacitance value of the input capacitor 116 and the capacitance value of the feedback capacitor 117. Furthermore, a virtual grounding operation is also possible, and a CDS (correlated double sampling) operation can be performed by a clamping operation using the input capacitor 116.

  Next, an example of a specific circuit of the column circuit will be described. The input capacitor 116 has a first node electrically connected to the common output line 107 and a second node electrically connected to the inverting input node of the operational amplifier 119. The first node of the feedback capacitor 117 is electrically connected to the inverting input node of the operational amplifier 119 and the second node of the input capacitor. The second node of the feedback capacitor 117 is electrically connected to the output node of the operational amplifier 119.

  The switch 118 is provided in a feedback path between the inverting input node and the output node of the operational amplifier 119 in order to control the electrical connection therebetween. The feedback capacitor 117 and the switch 118 are provided in parallel.

  The power supply 120 supplies the reference voltage Vref to the non-inverting input node of the operational amplifier 119. The holding capacitors 121 to 124 are capacitors that hold the output from the operational amplifier 119. The switches 125 to 128 are provided in an electrical path between the holding capacitors 121 to 124 and the operational amplifier 119, and control electrical continuity between the output node of the operational amplifier 119 and the holding capacitors 121 to 124. The switches 129 to 132 receive signals from the horizontal scanning circuit 114 and output the signals held in the holding capacitors 121 to 124 to the horizontal output lines 139 and 140. The output amplifier 115 takes the difference between the signals output to the horizontal output lines 139 and 140 and outputs the difference to the outside.

  The drive pulse PC0R is supplied to the switch 118. The driving pulse PTN is supplied to the switches 126 and 128. The drive pulse PTSA is supplied to the switch 125. The drive pulse PTSAB is supplied to the switch 127.

  Next, driving of the imaging apparatus of FIG. 1 will be described with reference to FIG. Any of the drive pulses is a high level pulse, and the element becomes conductive.

  First, at time T = t1, the drive pulses PTXA and PTXB supplied to the drive lines 109A and 109B become high level. At this time, since the drive pulse PRES supplied to the drive line 110 is at a high level, the photoelectric conversion elements 101A and 101B are reset.

  Next, at T = t2, the drive pulses PTXA and PTXB become low level. At this timing, the charge accumulation period in the photoelectric conversion elements 101A and 101B starts. Since the drive pulse PRES is maintained at the high level, the reset operation of the input node 103 of the amplifying unit 104 is continued.

  After accumulation for a predetermined period, signals are sequentially read out to the common output line 107 for each row or for every plurality of rows.

  At time T = t3, the drive pulse PSEL supplied to the drive line 111 of the selection transistor 106 becomes high level, and the selection transistor 106 becomes conductive. As a result, a signal corresponding to the potential of the input node of the amplifying unit 104 is output to the common output line 107.

  At time T = t4, the drive pulse PRES supplied to the drive line 110 of the reset transistor 105 is set to a low level, so that the reset operation of the input node 103 of the amplification unit 104 is released. The reset signal level is read to the common output line 107 and input to the column circuit. At this time, in the column circuit, the operational amplifier 119 is in a virtual ground state. Specifically, the drive pulse PC0R becomes high level and the switch 118 is in a conductive state. The operational amplifier 119 buffers the output of Vref. In this state, the reset signal level is supplied to the input capacitor 116.

  Next, at T = t5, the drive pulse PC0R is set to the low level, and at T = t6, the drive pulse PTN is switched from the low level to the high level, and the switches 126 and 128 are turned on. At T = t7, the drive pulse PTN is switched from the high level to the low level, and the switches 126 and 128 are turned off. By this operation, an output of approximately Vref is supplied to the holding capacitors 122 and 124, and then the holding capacitors 122 and 124 and the output node of the operational amplifier 119 become non-conductive.

  Subsequently, at T = t8, the drive pulse PTXA is set to the high level, the photoelectric charge of the photoelectric conversion element 101A is transferred to the input node 103 of the amplifying unit 104, and the drive pulse PTXA is set to the low level at T = t9. By this operation, the photoelectric charge of the photoelectric conversion element 101A is transferred to the input node 103. As a result, a signal based on the photocharge is supplied to the column circuit via the amplifier 104 and the common output line 107. By this operation, a focus detection signal can be generated on the common output line.

The column circuit outputs a value obtained by multiplying the voltage change by the inversion gain at the ratio of the capacitance value C0 of the input capacitor 116 and the capacitance value Cf of the feedback capacitor 117. Specifically, if the voltage change of the common output line 107 is ΔVa (negative) and the output of the operational amplifier 119 is V (A),
V (A) = Vref + ΔVa × (−C0 / Cf) Equation (1)
It becomes.

  Next, at T = t10, the drive pulse PTSA is switched from the low level to the high level, and the switch 125 is turned on. At T = t11, the drive pulse PTSA is switched from the high level to the low level, and the switch 125 is turned off. By this operation, the signal is held in the holding capacitor 121.

  Subsequently, at T = t12, the drive pulse PTXA is set to the high level, and the drive pulse PTXB is set to the high level during at least a part of the high level period of the drive pulse PTXA. With this operation, the photoelectric charges of both the photoelectric conversion elements 101A and 101B can be simultaneously transferred to the input node 103. By this operation, a signal for image formation can be generated on the common output line. The input node 103 of the amplifying unit 104 is not reset between the time when the signal of the photoelectric conversion element 102A is transferred and the time when the photoelectric charges of both the photoelectric conversion elements 101A and 101B are simultaneously transferred to the input node 103.

The charge transferred to the input node 103 of the amplifying unit 104 is supplied to the column circuit in the same manner as when only the charge of the photoelectric conversion element 101A is transferred. When the potential change of the common output line 107 is ΔVa + b (negative) and the output potential of the operational amplifier 119 is V (A + B), V (A + B) = Vref + ΔVa + b × (−C0 / Cf) (2)
It becomes.

  At T = t14, the drive pulse PTSAB is switched from the low level to the high level, and the switch 122 is turned on. At T = t15, the drive pulse PTSAB is switched from the high level to the low level, and the switch 122 is turned off. With this operation, the potential V (A + B) at the output node of the operational amplifier 119 can be written to the storage capacitor 123.

And the difference voltage between the capacitors CTSAB and CTN.
V (A + B) −Vref = ΔVa + b × (−C0 / Cf) Equation (3)
Can be obtained. This corresponds to a signal obtained by adding signals of two photoelectric conversion elements included in the photoelectric conversion unit. A signal corresponding to one pixel when imaging with a plurality of photoelectric conversion elements included in the photoelectric conversion unit is obtained.

Further, the potential difference V (A) −Vref = ΔVa × (−C0 / Cf) between the storage capacitors 121 and 122 (4)
As a result, a signal of only the photoelectric conversion element 101A can be obtained. The signal obtained by the photoelectric conversion element 101A corresponds to information on a light beam that passes through a part of the pupil of the focused photographing lens. Further, these potential differences, that is, (ΔVa + b × (−C0 / Cf)) − (ΔVa × (−C0 / Cf))
= (ΔVa + b−ΔVa) × (−C0 / Cf) Equation (5)
As a result, a signal of only the photoelectric conversion element 101B can be obtained. The signal obtained by the photoelectric conversion element 101B provides information on the luminous flux that passes through a part of the pupil of the focused photographing lens. The plurality of photoelectric conversion elements included in each photoelectric conversion unit are arranged at different positions in plan view. Then, focus detection can be performed from information of two light beams of the photoelectric conversion elements 101A and 101B.

  The calculation can be performed in the imaging apparatus, or can be performed in the signal processing unit after being output from the imaging apparatus. However, the signal of only the photoelectric conversion element 101A and the signal after addition of the photoelectric conversion elements 101A and 101B are obtained in the imaging apparatus.

  Next, at T = t16, the drive pulse PRES is set to the high level, the reset unit 105 is turned on, and the potential of the input node 103 is reset.

  The signals held in the holding capacitors 121 to 124 are read by sequentially turning on the drive pulses 133 and 134 synchronized with the pulse PH after T = t17. According to the present embodiment, since the output amplifier 115 capable of performing differential processing is provided at the subsequent stage of the horizontal output lines 139 and 140, the difference between the signals held in the holding capacitors 121 and 122 is transmitted to the outside of the imaging apparatus. Can be output. Further, the difference between the signals held in the holding capacitors 123 and 124 can be output to the outside of the imaging apparatus. Thereby, noise generated in the horizontal output lines 139 and 140 can be reduced. However, the output amplifier 115 is not necessarily configured to obtain a differential output, and may be a simple buffer stage. Thereafter, the signals in each column are sequentially scanned by the horizontal scanning circuit 114 and read out to the horizontal output lines 139 and 140.

  In addition, although the example of reading the addition signal of the photoelectric conversion elements A and B after reading the signal of only the photoelectric conversion element A is shown as the order of reading, the order may be changed. By reading the signal of only the photoelectric conversion element A first, a better signal can be obtained. This is because the longer the time held in the holding capacitors 121 to 124, the more easily affected by the leakage current caused by the capacitance and the switch.

  The feature of this embodiment is the operation during the period t11 to t15.

  Patent Document 1 discloses the following operation. The signal of the first photoelectric conversion element is written into the storage capacitor, the horizontal transfer operation is performed, and the signal is read out of the imaging device. Then, the reset operation is performed by the reset transistor. Thereafter, the signal of the second photoelectric conversion element is written to the storage capacitor, the horizontal transfer operation is performed, and the signal is read out of the sensor. Then, the reset operation is again performed by the reset transistor.

  In this case, a reading time difference (several tens to several hundreds μsec) for one row occurs between reading the signal of the first photoelectric conversion element and the signal of the second photoelectric conversion element.

  In this embodiment, the signal of the photoelectric conversion element 101A is completely read, and the signal is written to the storage capacitor at T = t11. While holding the signal of the photoelectric conversion element 101A at the input node 103, both signals of the photoelectric conversion elements 101A and 101B are read at T = t12. As a result, the reading time is greatly shortened (several μsec). Further, the time difference in signal readout between the photoelectric conversion elements 101A and 101B is shortened, and there is an effect of increasing the accuracy of focus detection.

  A secondary feature of this embodiment is the operation from time T = t8 to t15. The following effects can be obtained by simultaneously setting the drive pulses PTXA and PTXB to the high level.

  First, as a first point, generally, when the gate potential of the transfer transistor transitions from a low level to a high level, the potential of the input node 103 rises due to capacitive coupling between the drive wiring of the transfer transistor and the input node. In this embodiment, the gate potentials of the two transfer transistors 102A and 102B transition from the low level to the high level. Therefore, the increase in potential of the input node 103 is larger than in the case of one transfer transistor. When the potential of the input node 103 is increased, the charges of the photoelectric conversion elements 101 A and 101 B are easily transferred to the input node 103. Accordingly, transfer efficiency is improved.

  In particular, when one imaging pixel is divided into two photoelectric conversion elements as in the imaging apparatus of this embodiment, a potential barrier is often provided between the photoelectric conversion elements 101A and 101B. This potential barrier complicates the potential distribution of the photoelectric conversion element. For this reason, residual charge during transfer is likely to occur, and fixed pattern noise and random noise may occur. On the other hand, by setting the drive pulses PTXA and PTXB to the high level at the same time, there is an effect of reducing fixed pattern noise and random noise while the potential of the input node is high.

  As a second point, the difference in accumulation time between the photoelectric conversion elements 101A and 101B can be reduced. For example, in the configuration of Patent Document 1, the storage times of the two photoelectric conversion elements are shifted. On the other hand, as in the present embodiment, when adding at the input node 103, the accumulation time can be made uniform by making the timings at which all transfer gates corresponding to the photoelectric conversion elements to be added are turned off substantially the same. it can. This is particularly effective in a configuration for obtaining a focus detection signal on the imaging surface of the imaging apparatus.

  In this embodiment, the signal of one photoelectric conversion element is used to generate a focus detection signal, but this is not limited to the case where a larger number of photoelectric conversion elements are included in one photoelectric conversion unit. Absent. However, in order to obtain a focus detection signal, signals of all photoelectric conversion elements included in one photoelectric conversion unit cannot be used. The same applies to the following embodiments.

  In the second operation, the signals of all the photoelectric conversion elements (here, two) included in one photoelectric conversion unit are read out, but the present invention is not limited to this. At least the signal of the photoelectric conversion element which has not been read out in the first operation may be read out. This also applies to the following embodiments.

(Example 2)
FIG. 3 shows an equivalent circuit diagram of the image pickup apparatus of the second embodiment.

  The difference from the first embodiment is the configuration of the photoelectric conversion unit and the column circuit. The number of photoelectric conversion elements included in one photoelectric conversion unit is three, and accordingly, the number of storage capacitors included in the column circuit is also six. Parts having the same functions as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The photoelectric conversion unit 200 includes photoelectric conversion elements 101A to 101C. Compared to the first embodiment, since the number of divisions of the photoelectric conversion elements included in one pixel for imaging is increased, it is possible to perform focus detection with higher accuracy.

  Transfer transistors 102A to 102C that transfer charges of the photoelectric conversion elements 101A to 101C are included. PTXC is added as a drive pulse for the transfer transistor 102C.

  The column circuit 210 newly has a holding capacitor 201 for holding the signal after the addition of the photoelectric conversion elements 101A to 101C. A storage capacitor 202 for holding the noise level is also newly added. Corresponding to these, switches 203 to 206 are added.

  Next, the driving method of the image pickup apparatus of the present embodiment will be described with reference to FIG. Since the basic operation is the same as that in FIG. 2, the description will focus on the differences from the first embodiment.

  At time T = t12, both the drive pulses PTXA and PTXB are at a high level. By this operation, the signals of the photoelectric conversion elements 101A and 101B are added at the input node 103. Here, both the drive pulses PTXA and PTXB are set to the high level, but only the drive pulse PTXB may be set to the high level. At time T = t16, all the drive pulses PTXA, PTXB, and PTXC are set to the high level. By this operation, the charges of the photoelectric conversion elements 101A to 101C are added at the input node 103. At time T = t17, all the drive pulses PTXA, PTXB, and PTXC are set to the low level. Such an operation makes it possible to align the accumulation time of the photoelectric conversion elements 101A to 101C to the period t2 to t17.

  It is also possible to read out only the signals from the photoelectric conversion elements 101A and the addition signals from the photoelectric conversion elements 101A and 101B after reading out the addition signals from the photoelectric conversion elements 101A to 101C first.

  A better signal can be obtained by reading out the signal of only the photoelectric conversion element 101A, the addition signal of the photoelectric conversion elements 101A and 101B, and the addition signal of the photoelectric conversion elements 101A to 101C in this order. This is because the longer the time held in the holding capacitors 121 to 124, 201, and 202, the more susceptible to the influence of the capacitance and the leakage current due to the switch.

(Example 3)
FIG. 5 shows an equivalent circuit diagram of the image pickup apparatus of the third embodiment. The difference from the first and second embodiments is that the amplifying unit 104 is shared by a plurality of photoelectric conversion elements included in different photoelectric conversion units.

  5 includes a first photoelectric conversion unit having photoelectric conversion elements 501A and 501B and a second photoelectric conversion unit having photoelectric conversion elements 502A and 502B. Light collected by the first macro lens is incident on the plurality of photoelectric conversion elements included in the first photoelectric conversion unit, and is collected by the second micro lens on the plurality of photoelectric conversion elements included in the second photoelectric conversion unit. The emitted light is incident.

  Transfer transistors 503A, 503B, 504A, and 504B are provided corresponding to the respective photoelectric conversion elements 501A, 501B, 502A, and 502B. Drive lines 505A, 505B, 506A, and 506B are arranged as lines for supplying drive pulses to the transfer transistors 503A, 503B, 504A, and 504B.

  According to such a configuration, the amplification unit 104, the reset unit 105, and the selection unit 106 can be shared by a plurality of pixels for imaging. This makes it possible to reduce the number of transistors per pixel for imaging. As a result, the area of the photoelectric conversion element can be increased.

  With respect to the operation when sequentially reading out each of the photoelectric conversion elements 501A, 501B, 502A, and 502B, reading can be performed as signals in different rows by performing reading basically similar to that in FIG. Specifically, in the first photoelectric conversion unit, the signals of the photoelectric conversion elements 501A and 501B are added at the input node 103 after reading the signals of the photoelectric conversion elements 501A. As a result, both a focus detection amount signal and an imaging signal can be generated. Subsequently, after the signal of the photoelectric conversion element 502A is read out in the second photoelectric conversion unit, the signals of the photoelectric conversion elements 502A and 502B are added at the input node 103. As a result, both a focus detection amount signal and an imaging signal can be generated.

  Furthermore, in this embodiment, the amplification unit 104 is shared by two different photoelectric conversion units. Therefore, the signals of the photoelectric conversion elements 501A and 502A can be added at the input node 103, and the signals of the photoelectric conversion elements 501B and 502B can be added at the input node 103. An example of specific drive timing is shown in FIG. The description will focus on the characteristic features of the present embodiment. Here, the drive pulse supplied to the transfer transistor 503A is PTXA (505A), and the drive pulse supplied to the transfer transistor 503B is PTXB (505B). Further, the drive pulse supplied to the transfer transistor 504A is PTXA (506A), and the drive pulse supplied to the transfer transistor 504B is PTXB (506B).

  At time T = t8, the drive pulses PTXA (505A) and PTXA (506A) are changed from the low level to the high level. Thereafter, at time T = t9, the drive pulses PTXA (505A) and PTXA (506A) are changed from the high level to the low level. By this operation, signals of the photoelectric conversion elements 501A and 502A included in different photoelectric conversion units are added at the input node 103. This signal is used as a focus detection signal.

  At time T = t12, the drive pulses PTXA (505A), PTXB (505B), PTXA (506A), and PTXB (506B) are changed from the low level to the high level. Thereafter, at T = t13, the drive pulses PTXA (505A), PTXB (505B), PTXA (506A), and PTXB (506B) are changed from the low level to the high level. By this operation, the signals of all the photoelectric conversion elements 501A, 501B, 502A, and 502B included in different photoelectric conversion units are added at the input node 103. This signal is used as a signal for imaging.

  This operation improves the S / N because the focus detection signal is obtained by adding the signals of a plurality of photoelectric conversion elements included in different photoelectric conversion units. This makes it possible to detect the focus with higher accuracy.

  In the present embodiment, an example in which signals of two imaging pixels are added has been described, but the same effect can be obtained even if there are three or more.

Example 4
FIG. 7 is an equivalent circuit diagram of the image pickup apparatus according to the fourth embodiment. The difference of the present embodiment from the third embodiment is that a switch for electrically connecting a plurality of input nodes 103 is provided. Parts having the same functions as those of the first to third embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 7, the first photoelectric conversion unit includes photoelectric conversion elements 701A and 701B. The second photoelectric conversion unit includes photoelectric conversion elements 702A and 702B. The third photoelectric conversion unit includes photoelectric conversion elements 721A and 721B. The fourth photoelectric conversion unit includes photoelectric conversion elements 722A and 722B. A shared amplifying unit 707 is arranged for the first and second photoelectric conversion units. A shared amplifying unit 727 is arranged for the third and fourth photoelectric conversion units.

  Transfer transistors 703A, 703B, 704A, 704B, 723A, 723B, 724A, and 724B are arranged corresponding to the respective photoelectric conversion elements. Drive wirings 705A, 705B, 706A, 706B, 725A, 725B, 726A, and 726B for driving each transfer transistor are arranged.

  The switch 740 electrically connects the input nodes of the amplifying units 707 and 727. The switch 740 is controlled by the drive wiring 741.

  FIG. 8 shows a drive pulse diagram of FIG. Here, only portions corresponding to the first photoelectric conversion unit and the third photoelectric conversion unit are extracted and described. The second and fourth photoelectric conversion units can be driven in the same manner. The drive pulse PTXA (705A) is a pulse supplied to the drive wiring 705A. The drive pulse PTXB (705B) is a pulse supplied to the drive wiring 705B. The drive pulse PTXA (725A) is a pulse supplied to the drive wiring 725A. The drive pulse PTXB (725B) is a pulse supplied to the drive wiring 725B. PVADD (741) is a pulse supplied to the drive wiring 741.

  FIG. 8 shows an example in which signals from the photoelectric conversion elements 701A and 721A included in the first photoelectric conversion unit and the third photoelectric conversion unit are added.

  PVADD (741) is maintained at a high level during the period shown in FIG. That is, the input nodes of the amplifying units 707 and 727 are always electrically connected.

  At T = t8, the drive pulses PTXA (705A) and PTXA (725A) are changed from the low level to the high level. Thereafter, at time T = t9, the drive pulses PTXA (705A) and PTXA (725A) are changed from the high level to the low level. By this operation, signals from the photoelectric conversion elements 701A and 721A included in different photoelectric conversion units are transferred to the corresponding amplification units 707 and 727, respectively. Since the switch 740 is in a conductive state, both signals are added. This signal is used as a focus detection signal.

  At time T = t12, the drive pulses PTXA (705A), PTXB (705B), PTXA (725A), and PTXB (725B) are changed from the low level to the high level. Thereafter, at T = t13, the drive pulses PTXA (705A), PTXB (705B), PTXA (725A), and PTXB (725B) are changed from the low level to the high level. By this operation, the signals of the plurality of photoelectric conversion elements 701A, 701B, 721A, 721B included in different photoelectric conversion units are transferred to the corresponding amplification units 707, 727. Since the switch 740 is in a conductive state, all signals are added. This signal is used as a signal for imaging.

  In the present embodiment, a function of electrically connecting a plurality of input nodes is added. Thereby, in an imaging device having a color filter, it is suitable when signals of the same color are arranged apart from each other, for example, when a color filter having a Bayer array is provided. This is because it is possible to add signals of photoelectric conversion elements of the same color that are spaced apart. Therefore, not only the focus detection but also the S / N of the image signal can be improved, and high-quality image information can be obtained simultaneously with high-precision focus detection.

  In addition, although the example which connects two input nodes was shown in the present Example, the same effect is acquired also about three or more.

  Although the present invention has been described with reference to specific examples, the present invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Is possible. For example, the circuit configuration of the pixel is not limited to this, and may be configured to switch between selection and non-selection by switching the potential of the input node by the reset unit without having the selection unit. Furthermore, although the operational amplifier is provided as the column circuit, a simpler construction such as a common-source amplifier circuit may be employed. Alternatively, various modifications such as providing a plurality of gain stages or combining a gain stage and a buffer stage are possible. One common output line is provided for each pixel column, but a plurality of common output lines may be provided for one pixel column.

100, 200, 300, 700, 720 Photoelectric conversion units 101A, 101B, 501A, B, 502A, B, 701A, B, 702A, B, 721A, B, 722A, B Photoelectric conversion elements 104, 707, 727 Amplifier 105 , 708, 728 Reset unit 107 Common output line

Claims (15)

A plurality of photoelectric conversion units each having a plurality of photoelectric conversion elements; a plurality of amplifying units each amplifying signals of the plurality of photoelectric conversion elements shared by the plurality of photoelectric conversion elements of the photoelectric conversion unit; A plurality of common output lines from which signals from the amplification unit are output, a plurality of column circuits receiving signals from any of the plurality of common output lines, and signals processed by the plurality of column circuits are output. A driving method of an imaging device having a horizontal output line,
A focus is obtained by a first operation of reading a signal of at least one of the plurality of photoelectric conversion elements of the photoelectric conversion unit to an input node of the amplification unit and reading a signal to the common output line through the amplification unit. A signal for detection,
In a state where the signal read out by the first operation is held in the amplifying unit, the signal of the photoelectric conversion element that is included in the same photoelectric conversion unit and has not been read out at least in the first operation A signal for image formation is generated by the second operation of reading to the input node of the amplifying unit and reading the signal to the common output line via the amplifying unit,
The focus detection signals and the image formation signals generated in the plurality of photoelectric conversion units in a predetermined row and held in the plurality of column circuits are collectively output to a horizontal output line. Method of driving an imaging apparatus. A plurality of photoelectric conversion units each having a plurality of photoelectric conversion elements; a plurality of amplifying units each amplifying signals of the plurality of photoelectric conversion elements shared by the plurality of photoelectric conversion elements of the photoelectric conversion unit; A plurality of common output lines from which signals from the amplification unit are output, a plurality of column circuits receiving signals from any of the plurality of common output lines, and signals processed by the plurality of column circuits are output. A plurality of photoelectric conversion elements, each of which is a driving method of an imaging device that receives light from different areas of the pupil of a photographing lens,
A first operation of reading a signal of at least one photoelectric conversion element among a plurality of photoelectric conversion elements of the photoelectric conversion unit to an input node of the amplification unit, and reading a signal to the common output line via the amplification unit;
In a state where the signal read out by the first operation is held in the amplifying unit, the signal of the photoelectric conversion element that is included in the same photoelectric conversion unit and has not been read out at least in the first operation A second operation of reading to the input node of the amplifying unit and reading a signal to the common output line via the amplifying unit;
The signals read in the first operation and the signals read in the second operation generated in the plurality of photoelectric conversion units in a predetermined row held in the plurality of column circuits are collectively A method for driving an imaging apparatus, characterized by outputting to a horizontal output line. A plurality of photoelectric conversion units each having a plurality of photoelectric conversion elements; a plurality of amplifying units each amplifying signals of the plurality of photoelectric conversion elements shared by the plurality of photoelectric conversion elements of the photoelectric conversion unit; A plurality of common output lines from which signals from the amplification unit are output, a plurality of column circuits receiving signals from any of the plurality of common output lines, and signals processed by the plurality of column circuits are output. A horizontal output line, and a lens array having a plurality of lenses arranged corresponding to each of the plurality of photoelectric conversion units, wherein each lens of the lens array has a plurality of photoelectric conversion units of the same photoelectric conversion unit. A method for driving an imaging device that focuses light on a conversion element,
A first operation of reading a signal of at least one photoelectric conversion element among a plurality of photoelectric conversion elements of the photoelectric conversion unit to an input node of the amplification unit, and reading a signal to the common output line via the amplification unit;
In a state where the signal read out by the first operation is held in the amplifying unit, the signal of the photoelectric conversion element that is included in the same photoelectric conversion unit and has not been read out at least in the first operation A second operation of reading to the input node of the amplifying unit and reading a signal to the common output line via the amplifying unit;
The signals read out in the first operation and the signals read out in the second operation, which are held in the plurality of column circuits and are generated in the plurality of photoelectric conversion units in a predetermined row, are collected together. A method for driving an imaging apparatus, characterized by outputting to a horizontal output line.   4. The driving method of the imaging apparatus according to claim 1, wherein an input node of the amplification unit is not reset between the first operation and the second operation. 5.   It has a lens array which has a plurality of lenses arranged corresponding to each of the plurality of photoelectric conversion units, and each lens of the lens array condenses on a plurality of photoelectric conversion elements of the same photoelectric conversion unit. The driving method of the imaging apparatus according to claim 1.   The driving method for an imaging apparatus according to claim 1, wherein a plurality of photoelectric conversion elements each included in different photoelectric conversion units share one amplification unit. During the first operation, signals of at least two photoelectric conversion elements included in each of the first and second photoelectric conversion units that share the amplification unit are added by the shared amplification unit,
In the second operation, the shared amplifying unit outputs signals from a plurality of photoelectric conversion elements included in the first photoelectric conversion unit and signals from a plurality of photoelectric conversion elements included in the second photoelectric conversion unit. The image pickup apparatus driving method according to claim 6, wherein the addition is performed in a step.   The imaging apparatus driving method according to claim 1, further comprising a switch that electrically connects a plurality of input nodes of the amplifying units. By electrically connecting the switch during the first operation, the input nodes of the plurality of amplification units are electrically connected, and the signals of the connected input nodes are added,
9. The switch according to claim 8, wherein the switch is turned on during the second operation to electrically connect the input nodes of the plurality of amplifying units and add signals of the connected input nodes. Driving method of the imaging apparatus. A plurality of transfer gates for transferring each signal of a plurality of photoelectric conversion elements to a corresponding input node of the amplifying unit;
In the first operation, by supplying a pulse that makes the transfer gate conductive, the signal of the photoelectric conversion element is transferred to the corresponding input node of the amplification unit,
During the second operation, a signal is transferred during the second operation in at least a part of a period during which the transfer gate corresponding to the photoelectric conversion element to which the signal is transferred during the first operation is in a conductive state. The driving method of the imaging apparatus according to claim 1, wherein both of the transfer gates corresponding to the photoelectric conversion elements are in a conductive state.   The method for driving an imaging apparatus according to claim 1, wherein the plurality of photoelectric conversion elements included in the photoelectric conversion unit are arranged at different positions in plan view.   Using the reset signal output to the common output line via the amplifier after resetting the potential of the input node of the amplifier after resetting the potential of the input node of the amplifier. The method for driving an imaging apparatus according to claim 1, wherein difference processing is performed on signals obtained by the first operation and the second operation. A plurality of photoelectric conversion units each having a plurality of photoelectric conversion elements; a plurality of amplifying units each amplifying signals of the plurality of photoelectric conversion elements shared by the plurality of photoelectric conversion elements of the photoelectric conversion unit; A plurality of common output lines from which signals of the amplification unit are output, a plurality of column circuits receiving signals from any of the plurality of common output lines, and signals processed by the plurality of column circuits are output. An imaging device having a horizontal output line,
A focus is obtained by a first operation of reading a signal of at least one of the plurality of photoelectric conversion elements of the photoelectric conversion unit to an input node of the amplification unit and reading a signal to the common output line through the amplification unit. A signal for detection,
In the state where the signal read out by the first operation is held in the amplification unit, at least the signal of the photoelectric conversion element included in the same photoelectric conversion unit and not read out in the first operation is sent to the amplification unit A signal for image formation is generated by a second operation of reading the signal to the input node and reading the signal to the common output line via the amplifier,
The focus detection signals and the image formation signals generated in the plurality of photoelectric conversion units in a predetermined row and held in the plurality of column circuits are collectively output to a horizontal output line. An imaging device. A plurality of photoelectric conversion units each having a plurality of photoelectric conversion elements; a plurality of amplifying units each amplifying signals of the plurality of photoelectric conversion elements shared by the plurality of photoelectric conversion elements of the photoelectric conversion unit; A plurality of common output lines from which signals of the amplification unit are output, a plurality of column circuits receiving signals from any of the plurality of common output lines, and signals processed by the plurality of column circuits are output. A horizontal output line,
Each of the plurality of photoelectric conversion elements is an imaging device that receives light from different regions of a pupil of a photographing lens,
A first operation of reading a signal of at least one photoelectric conversion element among a plurality of photoelectric conversion elements of the photoelectric conversion unit to an input node of the amplification unit, and reading a signal to the common output line via the amplification unit;
In the state where the signal read out by the first operation is held in the amplification unit, at least the signal of the photoelectric conversion element included in the same photoelectric conversion unit and not read out in the first operation is sent to the amplification unit And a second operation of reading a signal to the common output line through the amplifier,
The signals read in the first operation and the signals read in the second operation generated in the plurality of photoelectric conversion units in a predetermined row held in the plurality of column circuits are collectively An image pickup apparatus that outputs to a horizontal output line. A plurality of photoelectric conversion units each having a plurality of photoelectric conversion elements; a plurality of amplifying units each amplifying signals of the plurality of photoelectric conversion elements shared by the plurality of photoelectric conversion elements of the photoelectric conversion unit; A plurality of common output lines from which signals of the amplification unit are output, a plurality of column circuits receiving signals from any of the plurality of common output lines, and signals processed by the plurality of column circuits are output. And a lens array having a plurality of lenses arranged corresponding to each of the plurality of photoelectric conversion units, each lens of the lens array having a plurality of photoelectric conversions of the same photoelectric conversion unit An imaging device that focuses light on an element,
A first operation of reading a signal of at least one photoelectric conversion element among a plurality of photoelectric conversion elements of the photoelectric conversion unit to an input node of the amplification unit, and reading a signal to the common output line via the amplification unit;
In the state where the signal read out by the first operation is held in the amplification unit, at least the signal of the photoelectric conversion element included in the same photoelectric conversion unit and not read out in the first operation is sent to the amplification unit And a second operation of reading a signal to the common output line via the amplifier,
The signals read in the first operation and the signals read in the second operation generated in the plurality of photoelectric conversion units in a predetermined row held in the plurality of column circuits are collectively An image pickup apparatus that outputs to a horizontal output line.

Images