JP2006134928A - Photoelectric converter, photoelectric converter for photometry automatic focusing, and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide high accuracy of measurement and large measuring range in which dynamic range does not become narrow, and measurable ranges of light quantity and temperature do not become narrow, even when the supply voltage of a photoelectric converter is changed. <P>SOLUTION: The photoelectric converter includes a photodiode 1 using a pn junction, a logarithmic transformation portion C1 which transforms a photocurrent generated in the photodiode 1 into a logarithmic compression voltage, an inverting amplifier circuit C2 which amplifies output of the logarithmic transformation portion C1, an Is compensation circuit C3 which corrects the diode reverse saturation current property of pn junction from the output of the inverting amplifier circuit C2, an amplifier C4 which amplifies the output of the Is compensation circuit C3. The amplifier C4 switches the amount of gain and the amount of DC offset according to the supply voltage Vc of a reference voltage source 4 between two different patterns, by switching the connecting state of a plurality of resistive elements 15-19 for specifying the amount of gain and the amount of offset by analog switches 20-23. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photoelectric conversion device, a photometric autofocus photoelectric conversion device, and an imaging device, and more particularly to an autofocus photometric photoelectric conversion device and an imaging device used in a photometry device of a camera.

  As a photoelectric conversion device, there is known a device that converts an optical signal into a signal proportional to a logarithm and outputs it in order to obtain a wide dynamic range in addition to an optical signal amount linear with respect to input light. As such a logarithmic compression photoelectric conversion device, there is one using a LOG amplifier. When a diode is used for logarithmic compression, it is common to provide a circuit that compensates for variations in the saturation current Is, and there is an example in which the Is compensation circuit is used as a thermometer with a built-in sensor (see, for example, Patent Document 1). Hereinafter, the prior art will be described with reference to FIG.

  In the logarithmic compression photoelectric conversion device shown in FIG. 7, 101 is a photodiode that outputs a current proportional to the photocurrent, 102, 107, 114, and 119 are CMOS operational amplifiers (hereinafter referred to as “first to fourth operational amplifiers”). 103 and 113 are PN junction diodes. In the first and third operational amplifiers 102 and 114, feedback loops from the output terminal to the (−) input terminal through the diodes 103 and 113 are formed. is doing. Reference numeral 104 denotes a reference voltage source connected to the input terminal of the photodiode 101 and the first to fourth operational amplifiers 102, 107, 114, and 119. 105, 106, 108, 109, 115, 116, 117, and Reference numeral 118 denotes a resistance element that defines the gain amount and DC (direct current) offset amount of the second to fourth operational amplifiers 107, 114, and 119. Reference numerals 110 and 111 denote the output terminal of the second operational amplifier 107 and the (− ) A CMOS analog switch for switching on / off between the input terminals, the (+) input terminal of the third operational amplifier 114 and the reference voltage source 104, and 112 is connected to the (−) input terminal of the third operational amplifier 114. A constant current source 120 is an output terminal of the apparatus.

  The PN junction formed by the photodiode 101 is formed by any two terminals of the base, emitter, and collector of the NPN bipolar transistor, and the remaining one terminal is connected to the semiconductor substrate.

  The photodiode 101 is connected to a logarithmic converter C1 that is negatively fed back from the output terminal of the first operational amplifier 102 and connected to the (−) input terminal via the diode 103, and a reference voltage source 104. The cathode terminal of the photodiode 101 is connected to the (−) input terminal of the first operational amplifier 102, and both input terminals of the first operational amplifier 102 to which the voltage of the (−) input terminal has applied negative feedback are substantially at the same potential. The potential of the reference input terminal of the reference voltage source 104 (hereinafter referred to as “Vc”) becomes the same potential due to an imaginary short (virtual short circuit), and the anode terminal is connected to the reference voltage source 104. The photodiode 101 is connected to the first operational amplifier 102 and the reference voltage source 104 with the cathode terminal side being higher in potential than the anode terminal side and reverse-biased in this way. Yes.

  According to this, when light is incident on the photodiode 101, a corresponding photocurrent Ip flows. This photocurrent Ip is fed back from the output terminal of the first operational amplifier 102 and supplied to the (−) input terminal side of the first operational amplifier 102 via the PN junction of the diode 103, from which the photodiode 101 and the reference voltage source 104 are connected. It flows to the constant voltage input terminal. At this time, when the reference voltage of the constant voltage input terminal of the reference voltage source 104 is Vc and the voltage of the output terminal of the first operational amplifier 102 is V1, the output of the voltage V1 is expressed by the following equation.

In this equation, Is is the reverse saturation current of the diode 101 (the maximum current that flows when a reverse voltage is applied to the diode), q is the elementary charge 1.602 × 10 ^-19 (Coulomb), and k is the Boltzmann constant 1.38. × 10 ^-23 (J / K), T is the absolute temperature (K).

  As can be seen from this equation, the output of the voltage V1 is proportional to the logarithm (LOG) of the light amount / photocurrent in the photodiode 101 by the logarithmic converter C1 connected to the photodiode 101. A wide dynamic range characteristic can be obtained.

  In addition, a circuit including the resistance elements 105 (input resistance) and 106 (feedback resistance) connected to the subsequent stage of the logarithmic conversion unit C1 and the second operational amplifier 107 is an inverting amplifier circuit C2. Here, assuming that the resistance values of the resistance elements 105 and 106 are R5 and R6 and the voltage (output of the intermediate potential) of the output terminal of the second operational amplifier 107 is V2, the output of the intermediate potential V2 is expressed by the following equation. .

  Here, assuming that the relationship between the resistance values R5 and R6 of the resistance elements 105 and 106 is R5 = R6, the output of the intermediate potential V2 is expressed by the following equation.

  A circuit including the diode 113, the third operational amplifier 114, and the constant current source 112 connected to the subsequent stage of the inverting amplifier circuit C2 is a circuit that compensates for variations in the reverse saturation current Is of the diode 103 (hereinafter referred to as “Is”). Compensation circuit C3 "). Here, when the current flowing to the constant current source 112 is Iref and the voltage (intermediate potential) of the output terminal of the third operational amplifier 114 is V3, the output of the intermediate potential V3 is expressed by the following equation.

  Here, assuming that the characteristics of the two diodes 103 and 113 are equal, the output of the intermediate potential V3 is expressed by the following equation.

  From this equation, an output of the intermediate potential V3 that does not depend on the reverse current saturation current Is of the diode 103 is obtained as a logarithmically compressed optical signal.

  When the analog switch 110 is opened, V2 = 0. Therefore, the output of the intermediate potential V3 is expressed by the following equation.

  According to this equation, when the analog switch 110 is opened, the output of the intermediate potential V3 can be used as a detection signal of a thermometer proportional to the absolute temperature T.

  Further, the circuit composed of the resistance elements 115, 116, 117, 118 and the fourth operational amplifier 119 connected to the subsequent stage of the Is compensation circuit C3 includes an optical signal logarithmically compressed through the circuits C1 to C3 and a detection signal of the thermometer. The amplifying unit C4 amplifies the output of the intermediate potential V3 used as Here, the resistance values of the resistance elements 115, 116, 117, and 118 are R15, R16, R17, and R18, respectively, the voltage of the output terminal of the fourth operational amplifier 119 is V4, and this apparatus connected to the voltage V4. Assuming that the voltage at the output terminal 120 is Vout, the output of the voltage V4, that is, the output voltage Vout is expressed by the following equation.

In this equation, the coefficient (slope) of V3 in the first term on the right side corresponds to the gain amount of the amplifying unit C4, and the second term (intercept) on the right side corresponds to the DC (direct current) offset amount of the amplifying unit C4.
JP 2003-243690 A

  However, in the logarithmic compression photoelectric conversion device of the above conventional example, the gain amount and the DC offset amount of the amplifying unit C4 are fixed as shown in the above formula, so that a problem occurs when the power supply voltage of the sensor is changed. For example, when the power supply voltage is changed higher, the output slope with respect to the light intensity or temperature is the same, so the measurement accuracy does not change, but when the power supply voltage is changed lower, the dynamic range becomes narrower and measurement is possible. The light amount range and the temperature range become narrow. As a result, it is difficult to realize high measurement accuracy and a wide measurement range in an imaging apparatus using a conventional logarithmic compression photoelectric conversion apparatus.

  The present invention has been made in consideration of such conventional circumstances, and even when the power supply voltage of the photoelectric conversion device is changed, the dynamic range is not narrowed, and the measurable light amount range and temperature range are not narrowed. The objective is to achieve high measurement accuracy and a wide measurement range.

  In order to achieve the above object, the present invention converts a photoelectric current that is output in proportion to the light intensity and a photoelectric current generated in the photoelectric conversion portion into a voltage that is proportional to the logarithm using a diode characteristic of a PN junction. In a photoelectric conversion device comprising a logarithmic conversion unit and a temperature measurement unit, and amplification means for amplifying the signals, the photoelectric conversion device has means for switching the gain amount and DC offset amount of the amplification means in at least two different patterns. It is characterized by.

  According to the photoelectric conversion device of the present invention, since the gain amount and the DC offset amount of the amplifying unit are switched by at least two different patterns, the gain amount is large when the power supply voltage is high, and the gain is large when the power supply voltage is low. The amount of DC offset can be adjusted so that the amount is small and the center of the measurement range coincides with the center of the output dynamic range. As a result, in the imaging apparatus equipped with the photoelectric conversion device according to the present invention, it is possible to realize high measurement accuracy and a wide measurement range even when the power supply voltage of the photoelectric conversion device is changed.

  Hereinafter, embodiments of a photoelectric conversion device, a photometric autofocus photoelectric conversion device, and an imaging device according to the present invention will be described with reference to FIGS.

  FIG. 1 illustrates the overall configuration of the photoelectric conversion device of this embodiment.

  In the photoelectric conversion device shown in FIG. 1, a photodiode 1, a logarithmic converter C1 (first operational amplifier 2, PN junction diode 3), a reference voltage source 4, an inverting amplifier circuit C2 (resistive elements 5, 6 and second operational amplifier 7). , Is compensation circuit C3 (resistive elements 8 and 9, CMOS analog switches 10 and 11, constant current source 12, diode 13, and third operational amplifier 14) are the same as the components 101 to 114 of the conventional apparatus shown in FIG. Since it is a structure, description of the structure and operation | movement is abbreviate | omitted. Further, the calculation formulas of the output voltages V1 to V3 of the respective stages based on these components 1 to 14 are the same as the above-described formulas ([Formula 1] to [Formula 6]), and thus the description thereof is omitted. To do.

  In the photoelectric conversion device shown in FIG. 1, reference numerals 15, 16, 17, 18, and 19 denote resistance elements, 20, 21, 22, and 23 denote analog switches, 24 denotes a fourth operational amplifier, and 25 denotes an output terminal. ˜25, that is, the amplifying unit C4 switches the resistance elements 15, 16, 17, 18, and 19 that define the gain amount and the DC offset amount by the analog switches 20, 21, 22, and 23, thereby obtaining the gain amount And the DC offset amount are switched in two patterns, respectively, and thereby, the output voltage V3 from the third operational amplifier 14 of the Is compensation circuit C3 is configured to be a non-inverting amplifier circuit (non-inverting amplifier circuit) that outputs the gain voltage and DC offset. Has been.

  In the amplifying unit C4 including the normal amplifier circuit shown in FIG. 1, the resistor element 15 is connected to the output V3 side of the third operational amplifier 14, and the resistor elements 16 and 17 are connected in series to the resistor element 15. 17 is connected to the output terminal of the fourth operational amplifier 24, the analog switch 20 is connected between the connection point between the resistive element 15 and the resistive element 16 and the (−) input terminal of the fourth operational amplifier 24, and the resistive element 16 and the resistive element are connected. An analog switch 21 is connected between the connection point between the elements 17 and the (−) input terminal of the fourth operational amplifier 24. The resistor 18 is connected to the connection point between the analog switch 20 and the (−) input terminal of the fourth operational amplifier 24, and the resistor 19, the analog switch 22, and the analog switch 23 are connected between the resistor 18 and the ground terminal. And are connected in parallel. The analog switches 20 to 23 can be opened and closed in response to an opening / closing control command from a control unit (controller) (not shown).

  In the amplifying unit C4 configured in this manner, by closing either one of the analog switches 20 and 21, the connection relationship of the resistance elements 15, 16, and 17 on the (−) input terminal side of the normal amplification circuit is variably defined. Resistance value (input resistance value and feedback resistance value) is adjusted, the gain amount is selected, and one of the analog switches 22 and 23 is closed to close the (+) input terminal side resistance element of the forward amplification circuit The DC offset amount can be selected by adjusting the resistance value variably defined by the connection relationship of 18 and 19.

  For example, when the resistance values of the resistance elements 15, 16, 17, 18, and 19 are R15, R16, R17, R18, and R19, respectively, the fourth corresponding to the voltage of the output terminal 25 when the analog switches 20 and 23 are closed. The output voltage V4 of the operational amplifier is expressed by the following equation.

  In this equation, the coefficient (slope) of V3 in the first term on the right side corresponds to the gain amount of the amplifying unit C4, and the second term (intercept) on the right side corresponds to the DC offset amount of the amplifying unit C4.

  When the analog switches 21 and 22 are closed, the output voltage V4 is expressed by the following equation.

  Therefore, according to the present embodiment, by changing the connection state of the plurality of resistance elements 15 to 19 by opening and closing the analog switches 21 to 23, the gain amount and the DC offset amount of the amplifying unit C4 composed of the forward rotation amplifier circuit are changed. Since each can be switched in two different patterns, the gain amount is increased when the power supply voltage of the photoelectric conversion device is high, the gain amount is decreased when the power supply voltage is low, and the center of the measurement range is the center of the output dynamic range. The DC offset amount can be adjusted so as to match. As a result, when this photoelectric conversion device is mounted on a camera, high measurement accuracy and a wide measurement range can be realized even when the power supply voltage of the photoelectric conversion device is changed.

  In the present embodiment, the case where there are two switching patterns for the gain amount and the DC offset amount has been described, but the present invention is not limited to this and may be two or more. For example, as shown in FIG. 2, the additional resistance elements 16a to 16c and 19a to 19e and the analog switches 21a to 21d and 22a to 22e are repeatedly inserted in parallel into the amplification unit C4 shown in FIG. Accordingly, the number of switching patterns can be increased to two or more.

  FIG. 3 is a schematic circuit diagram of the photoelectric conversion apparatus according to this embodiment. In FIG. 3, the description of the components that are substantially the same as those of the first embodiment shown in FIG. 1 is omitted.

  In the photoelectric conversion device shown in FIG. 3, reference numerals 31, 32, 33, 34, 35, and 36 denote resistance elements, 37, 38, and 39 denote analog switches, 40 denotes a fourth operational amplifier, and 41 denotes an output terminal. .., 41, that is, the amplifying unit C4 switches the resistance elements 31 to 36 that define the gain amount and the DC offset amount by the analog switches 37, 38, and 39, thereby changing the gain amount and the DC offset amount into two patterns. Thus, the output voltage V3 from the third operational amplifier 14 of the Is compensation circuit C3 is configured to be an inverting amplifier circuit that outputs the gain voltage and DC offset.

  In the amplifying unit C4 including the non-inverting amplifier circuit shown in FIG. 3, a resistance element 31 forming an input resistance is connected to the output V3 side of the third operational amplifier 14, and between the (−) input terminal and the output terminal of the fourth operational amplifier 24. The resistive element 32, the resistive element 33, and the analog switch 33 are connected in parallel to each other on the feedback circuit side formed by connecting. Resistive elements 34, 35, and 36 are connected between the (+) input terminal of the fourth operational amplifier 24 and the reference voltage Vc of the reference voltage source 4 via analog switches 38 and 39, respectively. The analog switches 37 to 39 can be opened and closed in accordance with an opening / closing control command from a control unit (controller) (not shown).

  In the amplifying unit C4 configured in this way, the resistance elements 32 and 33 on the feedback circuit side that connect between the (−) input terminal and the output terminal of the inverting amplifier circuit depending on whether the analog switch 37 is closed or not are connected. A variable resistance value (feedback resistance value) is selected to select a gain amount, and either one of the analog switches 38 and 39 is closed to close the resistance between the (+) input terminal of the inverting amplifier circuit and the reference voltage Vc. The DC offset amount can be selected by changing the resistance value variably defined depending on the connection state of the elements 34, 35, and 36.

  For example, assuming that the resistance values of the resistance elements 31, 32, 33, 34, 35, and 36 are R31, R32, R33, R34, R35, and R36, and the analog switches 37 and 38 are closed and the analog switch 39 is opened, The voltage Vout at the output terminal 41 is expressed by the following equation.

  In this equation, the coefficient (slope) of V3 in the first term on the right side corresponds to the gain amount of the amplifying unit C4, and the second term (intercept) on the right side corresponds to the DC offset amount of the amplifying unit C4.

  When the analog switches 37 and 38 are opened and the analog switch 39 is closed, the voltage Vout is expressed by the following equation.

  Therefore, according to the present embodiment, as in the first embodiment, the connection state of the plurality of resistance elements 31 to 36 is changed by opening and closing the analog switches 37 to 39, whereby the amplification unit C4 including the inverting amplification circuit is changed. Since the gain amount and the DC offset amount can be switched in two different patterns, respectively, the gain amount is increased when the power supply voltage of the photoelectric conversion device is high, the gain amount is decreased when the power supply voltage is low, and the measurement range The DC offset amount can be adjusted so that the center coincides with the center of the output dynamic range. As a result, when this photoelectric conversion device is mounted on a camera, high measurement accuracy and a wide measurement range can be realized even when the power supply voltage of the photoelectric conversion device is changed.

  In the present embodiment, the switching pattern can be further increased by inserting additional resistance elements and analog switches in parallel as in the first embodiment.

  FIG. 4 is a schematic circuit diagram of the photoelectric conversion device according to this embodiment. 4, description of components substantially the same as those of the first embodiment shown in FIG. 1 is omitted.

  The amplifying unit C4 shown in FIG. 4 has the input polarities of the fourth operational amplifier 24 in the amplifying unit C4 of the first embodiment opposite to each other, and the connection terminal sides of the (−) and (+) input terminals are connected to the first embodiment. The reference voltage VC of the reference voltage source 4 (see FIG. 1) is connected to the (−) input terminal side, and the output V3 of the third operational amplifier 14 (see FIG. 1) is connected to the (+) input terminal side. The circuit includes a normal amplifier circuit configured as described above and an inverting amplifier circuit connected to the subsequent stage of the normal amplifier circuit and provided with a gain switching function.

  In the inverting amplifier circuit of the amplifier unit C4 shown in FIG. 4, reference numerals 41, 42, and 43 denote resistance elements, 44 and 45 denote analog switches, and 46 denotes a fifth operational amplifier. That is, the resistance element 41 is connected to the output side V4 side of the fourth operational amplifier 24, the resistance elements 42 and 43 are connected in series to the resistance element 41, and the resistance element 43 is connected to the output terminal of the fifth operational amplifier 46, The analog switch 44 is connected between the connection point between the resistance element 41 and the resistance element 42 and the (−) input terminal of the fifth operational amplifier 46, and the connection point between the resistance element 42 and the resistance element 43 and the fifth operational amplifier 46 ( -) Analog switches 45 are respectively connected between the input terminals. The (+) input terminal of the fifth operational amplifier 46 is connected to the (−) input terminal side of the fourth operational amplifier 24. The analog switches 44 and 45 can be opened and closed in response to an opening / closing control command from a control unit (controller) (not shown).

  In the amplifying unit C4 thus configured, the output of the output voltage V4 of the fourth operational amplifier 24 in the forward non-inverting amplifier circuit is the calculation formula of the output voltage V4 of the fourth operational amplifier 24 of the above-described first embodiment ([[ In [Equation 8] and [Equation 9]), it is expressed by an expression in which VC and V3 are interchanged (expression omitted). In this case, since the output V4 has a negative slope with respect to the light amount or the temperature, the same result as in the first embodiment is obtained by converting the output V4 to a positive slope by the inverting amplifier circuit in the next stage and outputting it as the voltage Vout. Is obtained.

  Therefore, according to the present embodiment, in addition to the same effects as those of the first embodiment, the gain switching pattern can be further increased as compared with the first embodiment by providing a gain switching function in the subsequent inverting amplifier circuit. Thus, a finer gain setting becomes possible.

  In the present embodiment, a photometric autofocus solid-state imaging device in which the photoelectric conversion devices according to the first to third embodiments are mounted as a photometric circuit block will be described. FIG. 5 is a conceptual block diagram of the photometric autofocus solid-state imaging device.

  The solid-state imaging device for photometry autofocus shown in FIG. 5 includes an AF (autofocus) circuit block 130 as an autofocus circuit block, an AE (auto exposure) circuit block 140 as a photometry circuit block, an analog circuit block 150, logic A circuit 160 and an external microcomputer 170 are provided.

  The AF circuit block 130 is composed of a pair of AF linear sensors A131 and B132 to perform autofocusing at one position, and auto-focusing using the trigonometric autofocus method is possible using the two linear sensors A131 and B132. It is said.

  The AE circuit block 140 is configured using the photoelectric conversion devices of the first to third embodiments, and includes a logarithmic compression type AE sensor 141 corresponding to the photodiode 1 and the logarithmic conversion unit C1, and the inverting amplification circuit C2. It comprises a corresponding inverting amplifier circuit 142, an Is compensation circuit 143 having a thermometer function corresponding to the Is compensation circuit C3, and a signal amplification circuit 144 corresponding to the amplification section C4.

  The analog circuit block 150 includes an auto gain control (AGC) circuit 151 for controlling the accumulation time of the AF sensors A131 and B132, a reference potential generation circuit (bandgap circuit) 152 for generating a reference potential, and a sensor circuit. An intermediate potential generation circuit (power supply circuit) 153 for generating an intermediate potential necessary for the operation, and an AF signal amplification circuit 154 for amplifying the AF signal from the AF circuit block 130 and outputting it to the outside.

  The logic circuit 160 includes an I / O circuit for performing communication with the external microcomputer 170.

  According to the present embodiment, the photoelectric conversion is performed by switching the gain amount and the DC offset amount of the AE output and the thermometer output of the AE circuit block 140 in two or more different patterns as described in the first to third embodiments. Even when the power supply voltage of the apparatus is changed, high resolution and a wide measurement range can be obtained.

  In the photometric autofocus photoelectric conversion device according to the present embodiment, the AF sensor used in the AF circuit block 130 is preferably a CMOS sensor manufactured by a CMOS (Complementary Metal Oxide Sensor) process. The same effect can be obtained even with a solid-state imaging device such as a Stored Image Sensor (SIT), Static Induction Transistor (SIT), Amplified MOS Intelligent Imager (AMI), Charge Modulation Device (CMD), or Charge-Coupled Device (CCD). Can do.

  In the present embodiment, an imaging apparatus using the photoelectric conversion apparatus according to any of the first to third embodiments as a solid-state imaging device (a solid-state imaging apparatus for photometric autofocus) having a photometric circuit block, an autofocus circuit block, and a thermometer circuit. explain.

  FIG. 6 is a block diagram showing an embodiment in which the photoelectric conversion devices according to Embodiments 1 to 3 are used in a lens shutter digital compact camera (imaging device).

  In FIG. 6, 201 is a barrier that serves as a lens switch and a main switch, 202 is a lens that forms an optical image of a subject on the solid-state imaging device 204, 203 is a diaphragm for changing the amount of light that has passed through the lens 202, and 204 is This is a solid-state imaging device for capturing the subject imaged by the lens 202 as an image signal.

  Reference numeral 205 denotes a photometric autofocus solid-state imaging device on which the photoelectric conversion devices of the first to third embodiments are mounted as an AE circuit block, an AF circuit block, and a thermometer circuit. An AEAF optical module is formed together with the lens. In the present embodiment, for example, the photoelectric conversion device of the first embodiment shown in FIG. 1 is used as the photometric autofocus solid-state image pickup device (photometry / distance solid-state image pickup device) 205 of the AEAF optical module. The AE circuit block, the AF circuit block, and the thermometer circuit constituting the photometric autofocus solid-state imaging device 205 are provided on the same semiconductor substrate, for example.

  Reference numeral 206 denotes an A / D converter that performs analog-to-digital conversion on an image signal, a photometric signal, and an autofocus signal output from the solid-state imaging device 204 or the solid-state imaging device 205 for photometric autofocus. 208 denotes an A / D converter 207. A signal processing unit 209 outputs various timing signals to the solid-state imaging device 204, the imaging signal processing circuit 206, the A / D converter 207, the signal processing unit 208, and the like. A timing generation unit 210 is an overall control / calculation unit that controls various calculations and the entire camera, and 211 is a memory unit for temporarily storing image data.

  Further, 212 is an interface unit for recording or reading on a recording medium, 213 is a removable recording medium such as a semiconductor memory for recording or reading image data, and 214 is an interface for communicating with an external computer or the like. Part.

  Next, an operation at the time of photographing with such a lens shutter digital compact camera will be described.

  First, when the barrier 201 is opened, the main power supply is turned on, the control system power supply is turned on, and the power supply of the imaging system circuit such as the A / D converter 207 is turned on. Next, the overall control / calculation unit 210 calculates the distance to the subject by triangulation based on the signal output from the AF circuit block of the photometric autofocus solid-state imaging device 205.

  Thereafter, the feeding amount of the lens 202 is calculated, and the lens 202 is driven to a predetermined position to be focused. Next, in order to control the exposure amount, the signal output from the AE sensor (AE circuit block) of the photometry autofocus solid-state imaging device 205 is converted by the A / D converter 207 and then input to the signal processing unit 208. Based on the data, the exposure calculation is performed by the overall control / calculation unit 210. The brightness is determined based on the result of the photometry, and the overall control / calculation unit 210 adjusts the aperture 203 and the shutter speed according to the result. After that, after the exposure conditions are set, the main exposure with the solid-state image sensor 204 starts.

  When the exposure is completed, the image signal output from the solid-state image sensor 204 is A / D converted by the A / D converter 207, passes through the signal processing unit 208, and is written in the memory unit 211 by the overall control / calculation 210. Thereafter, the data stored in the memory unit 211 is recorded on the removable recording medium 213 through the recording medium control I / F unit 212 under the control of the overall control / calculation unit 210. Further, it may be directly input to a computer or the like through the external I / F unit 214.

  Note that the photometric autofocus solid-state imaging device 205 of this embodiment can be used not only for a digital compact camera but also for a silver salt camera or the like.

It is a circuit diagram which shows the whole structure of the photoelectric conversion apparatus which concerns on Example 1 of this invention. It is a circuit diagram which shows the other example of the photoelectric conversion apparatus which concerns on Example 1 of this invention. It is a circuit diagram which shows the principal part of the photoelectric conversion apparatus which concerns on Example 2 of this invention. It is a circuit diagram which shows the principal part of the photoelectric conversion apparatus which concerns on Example 3 of this invention. It is a conceptual block diagram which shows the whole structure of the solid-state imaging device for photometry autofocus based on Example 4 of this invention. It is a system block diagram which shows the whole structure of the imaging device which concerns on Example 5 of this invention. It is a circuit diagram which shows the whole structure of the photoelectric conversion apparatus of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photodiode 2 1st operational amplifier 7 2nd operational amplifier 14 3rd operational amplifier 24, 40 4th operational amplifier 46 5th operational amplifier 3, 13 PN junction diode 4 Reference voltage sources 5, 6, 8, 9, 15-19, 16a-16c , 19a to 19e, 32 to 36, 41 to 43 Resistance element 10, 11, 20 to 23, 21a to 21d, 22a to 22e, 37 to 39, 44, 45 Analog switch 12 Constant current source 25, 41 Output terminal C1 Logarithm Conversion unit C2 Inversion amplification circuit C3 Is compensation circuit C4 Amplification unit

Claims (10)

A photoelectric conversion element using a PN junction;
A logarithmic conversion unit that converts a photoelectric current generated in the photoelectric conversion element into a logarithmic compression voltage;
Correction means for correcting the diode reverse saturation current characteristic of the PN junction from the output signal of the logarithmic conversion unit and functioning as a temperature detection means;
Amplifying means for amplifying the output of the correcting means with a predetermined gain amount and a DC offset amount;
The amplifying unit switches the gain amount and the DC offset amount with at least two different patterns. The photoelectric conversion device according to claim 1,
The photoelectric conversion apparatus according to claim 1, wherein the temperature detection means formed by the correction means uses temperature characteristics of the PN junction. In the photoelectric conversion device according to claim 1 or 2,
The PN junction is formed by any two terminals of a base, an emitter, and a collector of an NPN bipolar transistor, and the remaining one terminal is connected to a semiconductor substrate. In the photoelectric conversion device according to any one of claims 1 to 3,
The amplifying unit switches the gain amount and the DC offset amount according to a power supply voltage. In the photoelectric conversion device according to any one of claims 1 to 4,
The amplification means includes
A forward amplification circuit for amplifying the output of the correction means;
A photoelectric conversion apparatus comprising: a plurality of resistance elements configured to define a gain amount and a DC offset amount of the normal amplification circuit and to change the gain amount and the DC offset amount by switching a switch. In the photoelectric conversion device according to any one of claims 1 to 4,
The amplification means includes
An inverting amplifier circuit for amplifying the output of the correction means;
A photoelectric conversion device comprising: a plurality of resistance elements configured to define a gain amount and a DC offset amount of the inverting amplifier circuit, and to change the gain amount and the DC offset amount by switch switching. In the photoelectric conversion device according to any one of claims 1 to 4,
The amplification means includes
A forward amplification circuit for amplifying the output of the correction means;
A plurality of resistance elements configured to define a gain amount and a DC offset amount of the forward rotation amplification circuit and to be able to vary the gain amount and the DC offset amount by switch switching;
An inverting amplifier circuit that amplifies the output of the forward amplifier circuit;
A photoelectric conversion device comprising: a plurality of resistance elements configured to define a gain amount of the inverting amplifier circuit and to change the gain amount by switching a switch. A photoelectric conversion element for photometry comprising the photoelectric conversion device according to any one of claims 1 to 7,
A photoelectric conversion device for photometry autofocus, comprising a pair of autofocus photoelectric conversion element arrays for performing autofocus. The photoelectric conversion device for photometric autofocus according to claim 8,
The photometric photoelectric conversion device for photometry, wherein the photoelectric conversion device for photometry and the photoelectric conversion device array for automatic focus are provided on the same semiconductor substrate. A photoelectric conversion device for photometric autofocus according to claim 8 or 9,
An image pickup apparatus that performs temperature correction of an autofocus signal obtained by the photoelectric conversion element array for autofocus based on an output signal from the correction unit that constitutes the temperature measurement unit.