JPH11150686A - Photoelectric converter, its control method, focus detector and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively utilize a dynamic range and to reduce the circuit scale by controlling charge storage in a photoelectric conversion means that includes a photoelectric conversion element consisting of plural pixels and a storage means that stores prescribed control information based on the stored control means. SOLUTION: A controller 1 controls the operation of the entire converter, especially charge storage in each of sensor array blocks 21 -2n and is provided with a program memory 18 storing various processing programs in advance and controls the operation by reading and executing the stored processing program. Information (a value corresponding to a level c- level of an operation of end of charge storage) relating to each charge storage operation is written to each RAM (RAM171 -17n ) of the sensor array blocks 21 -2n corresponding to all areas 1-n. Thus, the charge storage operation of the sensor array blocks 21 -2n corresponding to the area 1-n is controlled independently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric conversion device applied to photographing equipment such as a camera and a video, various observation devices, and the like, a control method thereof, a focus detection device, and a control method of the photoelectric conversion device. The present invention relates to a storage medium in which processing steps for performing the above are stored in a computer-readable manner.

[0002]

2. Description of the Related Art Conventionally, a focus state of a subject is detected,
A variety of so-called autofocus (AF) cameras and the like have been proposed in which the focus is automatically adjusted by changing the distance of the photographing lens accordingly. In such an AF camera or the like, as a method of detecting a focus state, for example, a subject image is formed on a photoelectric conversion element (hereinafter, simply referred to as a sensor) including a plurality of photoelectric conversion pixels (hereinafter, simply referred to as pixels). A method of detecting a focus state by forming an image on a plurality of pixel signals and performing predetermined arithmetic processing on a plurality of pixel signals output from the sensor. In this method, in order to detect a focus state with high accuracy even for objects having various luminance levels, such as a high-luminance object to a low-luminance object, an amplification factor of signal reading by a sensor ( It is indispensable to appropriately control the charge accumulation time when the charge is accumulated. The reason for this is that if the level of an image signal (hereinafter, referred to as a video signal) of a subject composed of a plurality of pixel signals is too high, the dynamic range of the pixel signals that can be processed by the device is exceeded, and as a result, The signal may be different from the actual one and the accuracy may be worse. On the other hand, if the level of the video image signal is too low, the noise will relatively increase, which may also degrade the accuracy.

FIG. 8 shows a photoelectric converter 500 that controls the gain of reading pixel signals by the sensor 54 and the charge accumulation time.

The photoelectric converter 500 includes a sensor 54 composed of a plurality of pixels, a peak detection circuit 53 for detecting the maximum amount of accumulated charge during the accumulation of the charge by the sensor 54 and outputting the detected amount, and a sensor 54. A memory 52 in which the pixel signal is transferred and held after the charge accumulation in
5 and a level output circuit 56 for outputting a level value selected from a plurality of level values according to the count value of the counter 55
And a comparator 57 that compares each output of the level output circuit 56 and the peak detection circuit 53 and outputs the result, and a readout amplifier that outputs the pixel signal held in the memory 52 with a gain according to the count value of the counter 55 58.

[0005] Here, each unit provided in the photoelectric converter 500 is controlled by a controller 51. In particular, the controller 51 controls the charge accumulation operation of the sensor 54.

More specifically, as shown in FIG. 9, first, the controller 51 outputs a reset signal rst to the sensor 54 and the counter 55 (step S501).
As a result, the sensor 54 initializes all charges of each pixel, and resets the counter 55 to an initial value “0” (count = 0). Thereafter, the charge accumulation operation in the sensor 54 is actually started.

Next, the controller 51 sets an internal timer (not shown) to an initial value “0” (timer = 0) to start time measurement of the charge accumulation operation (step S502).

Next, the controller 51 determines whether or not the timer value timer of the internal timer has exceeded the maximum accumulation time Etime (step S503). As a result of this determination, "ti
mer ≧ Etime ”, the charge accumulation operation is terminated,
A signal trans indicating this is output to the sensor 54.
As a result, the electric charges accumulated in each pixel of the sensor 54 are transferred to the memory 52 as pixel signals, respectively.
Is completed (step S508).

On the other hand, as a result of the determination in step S503, "
If timer ≧ Etime ”, the controller 51
Indicates whether the output signal comp of the comparator 57 is “1”, that is, the output signal c_leve of the level output circuit 56.
It is determined whether or not l is greater than the output signal p_out of the peak detection circuit 53 (step S504). If the result of this determination is not "comp = 1", the flow returns to step S503, and the subsequent processing steps are repeated.

The output signal c_le of the level output circuit 56
Details of vel will be described later.

As a result of the determination in step S504, "comp =
If it is 1 ", the controller 51 determines whether or not the timer value timer of the internal timer has exceeded the intermediate accumulation time Htime (step S505). As a result of this determination," ti "
If mer ≧ Htime ”, the above-described step S
Proceeding to 508, the charge accumulation operation of the sensor 54 ends.

As a result of the determination in step S505, "timer
If ≧ Htime ”, the comparator 51 determines whether or not the count value count of the counter 55 is“ 3 ”(step S506).
If t = 3 ″, the above-described step S508 is performed.
And the charge accumulation operation of the sensor 54 ends.

As a result of the determination in step S506, "count
= 3 ", the controller 51 outputs the signal up_
c is output to the counter 55. Thus, the count value count of the counter 55 is counted up (step S507). Thereafter, the above-described step S5
03, and the subsequent processing steps are repeated.

As described above, the charge accumulation operation of the sensor 54 is controlled, and the memory 52 holding the pixel signal after the completion of the charge accumulation operation reads out the pixel signal by the signal shift output from the controller 51. The operation is controlled. The pixel signal s_out read from the memory 52 by this control is gained by the read amplifier 58 and output from the output terminal Vout. At this time, the read amplifier 58 applies a gain to the pixel signal s_out from the memory 52 according to the count value count of the counter 55.

As for the time of the charge accumulation operation in the sensor 54, the output signal c_level of the level output circuit 56 is used.
Is controlled by switching. Hereinafter, the charge storage operation time and the output signal c_level of the level output circuit 56 will be schematically described with reference to FIGS.

In the following description, the level output circuit 56
Has four levels "level1.0" to "level1.3", and switches and outputs these level values in accordance with the count value count of the counter 55. 10A and 10B, the horizontal axis represents the charge accumulation time, and the vertical axis represents the output signal c_level of the level output circuit 56.
And the value of the output signal p_out of the peak detection circuit 53. FIG. 10A shows a case where the subject is relatively bright and the peak output of each pixel signal, that is, the output signal p_out of the peak detection circuit 53, rises quickly. FIG. On the contrary, the case where the subject is relatively dark and the peak output of each pixel signal rises slowly is shown.

(In the case of FIG. 10A) When the charge accumulation operation is started, first, the count value count of the counter 55 is initialized (step S501), so that the output signal c_level of the level output circuit 56 is obtained. Becomes “level1.0”. Then, the charge accumulation operation time (timer value of the internal timer
timer) becomes "A-1", the peak detection circuit 53
Is the output signal c_of the level output circuit 56.
_Level, and as a result, when the output signal comp of the comparator 57 becomes “1”, the count value of the counter 55
The count is incremented (steps S503 to S507). By giving the counted value count which has been counted up to the level output circuit 56, the output signal c_level of the level output circuit 56 becomes “level1.1”.
Becomes Next, similarly, when the charge accumulation operation time becomes “A-2”, the count value count of the counter 55 is counted up, and the output signal c_leve of the level output circuit 56 is similarly increased.
l becomes “level1.2”. Next, the charge storage operation time
Similarly, when the value becomes A-3 ", the count value count of the counter 55 is counted up, and the output signal c_level of the level output circuit 56 becomes" level1.3 ". At this time, since the count value count of the counter 55 is "3" at this time, the charge accumulation operation of the sensor 54 ends (step S5).
As a result of the determination in step 06, the process proceeds to step S508).

(Case of FIG. 10 (B)) When the charge storage operation time is "B-1" and when the charge storage operation time is "B-1"
-2 ", the above-mentioned" A-1 "-"
A-3 ”, the count value of the counter 55
Are counted up, and the output signal of the level output circuit 56 is
c_level changes from “level1.0” to “level1.1”,
When the charge storage operation time reaches “A-3”, the peak detection circuit 5 changes from “level1.1” to “level1.2”.
Assuming that the charge accumulation operation time exceeds the intermediate accumulation time Htime due to the slow rise of the output signal p_out of No. 3
The charge accumulation operation of the sensor 54 ends (step S).
The process proceeds to step S508 as a result of the determination of 505).

As described above, by switching the output signal c_level of the level output circuit 56 in four stages, when the subject is bright, the charge accumulation operation time is sufficiently long,
The charge accumulation operation time is controlled in accordance with the situation of the object, such that the charge accumulation operation time is not made too long when the subject is dark.

The gain of the read amplifier 58 is controlled according to the count value of the counter 55.
This means that the gain of the readout amplifier 58 is controlled in accordance with the peak output (p_out) of the pixel signal. As a result, the pixel signal readout always effectively utilizes the dynamic range of the pixel signal that can be processed by the device. Is possible.

[0021]

However, when the conventional photoelectric converter 500 as described above is used in a multi-point AF camera capable of performing an AF function for a plurality of distance measuring points, for example, It is necessary to provide all the components including the comparator 57 and the like as shown in FIG. 8 for the distance measuring point, so that the circuit scale becomes enormous and the area of the IC chip increases. There was a problem.

In order to solve this problem, one sensor is divided into regions for each ranging point, and while each region is sequentially scanned, one sensor is divided.
A method of controlling the charge accumulation operation time by one controller is conceivable. According to this method, an increase in the area of the IC chip is suppressed, and a multipoint AF with a reasonable chip size is achieved.
Can be realized.

However, in this method, in order to control the charge accumulation time in the area (sensor) of each ranging point, when scanning is performed by means of reading out pixel signals from each area and comparing them, one type of scanning is performed. Focusing on the area, during the charge storage operation, it is determined whether or not to end the charge storage operation intermittently. When such a method is adopted for the photoelectric converter 500 shown in FIG. 8, the output signal c_level of the level output circuit 56 immediately after the start of the charge accumulation operation.
Is “level1.0”, the counter value count of the counter 55 becomes “3” for a high-luminance subject in which the output signal p_out of the peak detection circuit 53 rapidly rises, and the charge accumulation operation is performed. Will end. For this reason, it takes a very long time, it is impossible to properly control the charge accumulation operation time, and the level of the video signal of the subject exceeds the dynamic range, which may cause a problem of image distortion.

Therefore, the present invention has been made to eliminate the above-mentioned drawbacks, and it is always possible to appropriately control the charge accumulation operation for any subject and to effectively utilize the dynamic range of the pixel. A signal can be read out, high-precision autofocusing is possible, and furthermore, a photoelectric conversion device, a control method thereof, a focus detection device, and a photoelectric conversion device which realizes this at a low cost without increasing the circuit scale It is an object of the present invention to provide a storage medium in which processing steps for implementing a control method of a conversion device are stored in a computer readable manner.

[0025]

For such a purpose,
According to a first aspect, a photoelectric conversion unit including a photoelectric conversion element including a plurality of pixels and a storage unit that stores predetermined control information;
Control means for controlling the charge accumulation operation of the photoelectric conversion means based on the control information stored in the storage means.

According to a second aspect, in the first aspect,
The photoelectric conversion unit further includes a monitor unit that monitors and outputs a state of the accumulated charge in the photoelectric conversion element, and the control unit determines an arbitrary state from a plurality of state information based on control information stored in the storage unit. A selector for selecting information; and a comparator for comparing the output of the monitor with the status information selected by the selector. The charge storage operation of the photoelectric converter based on the comparison result of the comparator. Is controlled.

According to a third aspect of the present invention, there is provided a photoelectric conversion unit including a photoelectric conversion element composed of a plurality of pixels and a storage unit for storing predetermined control information, and amplifies a signal of the charge stored in the photoelectric conversion element at a predetermined amplification factor. And a control means for controlling an amplification factor in the reading means based on the control information stored in the storage means.

According to a fourth aspect, in the third aspect,
The photoelectric conversion unit further includes a monitor unit that monitors and outputs a state of the accumulated charge in the photoelectric conversion element, and the control unit determines an arbitrary state from a plurality of state information based on control information stored in the storage unit. A selection means for selecting information; and a comparison means for comparing the output of the monitoring means with the state information selected by the selection means, and controls an amplification factor in the reading means based on a comparison result of the comparison means. It is characterized by doing.

According to a fifth aspect, in the first or third aspect, a plurality of the photoelectric conversion units are provided.

In a sixth aspect based on the second or fourth aspect, the monitor means monitors and outputs information based on the maximum accumulated charge amount of the photoelectric conversion element.

In a seventh aspect based on the second or fourth aspect, the control means stores the state information selected by the selection means in the storage means as the control information.

An eighth invention is characterized in that, in the first or third invention, the photoelectric conversion means is formed by forming the photoelectric conversion element and the storage means on the same substrate.

In a ninth aspect based on the first or third aspect, the control means includes a determination means for determining predetermined information based on a signal of the stored charge read from the photoelectric conversion means, The information determined by the determining means is stored in the storage means as the control information.

A tenth invention is a control method for controlling a charge accumulation operation in a photoelectric conversion element comprising a plurality of pixels,
A control step of reading control information of a memory provided corresponding to the photoelectric conversion element and controlling a charge accumulation operation in the photoelectric conversion element based on the control information.

According to an eleventh aspect based on the tenth aspect, the control step is based on a monitor output step of monitoring and outputting a state of accumulated charges in the photoelectric conversion element and control information read from the memory. A selection step of selecting arbitrary state information from a plurality of state information; a comparison step of comparing the monitor output by the monitor output step with the state information selected by the selection step; and a comparison step based on a comparison result of the comparison step. And a storage operation control step of controlling a charge storage operation in the photoelectric conversion element.

[0036] In a twelfth aspect based on the tenth aspect, the control step is performed by each photoelectric conversion element based on control information of a plurality of memories provided corresponding to the plurality of photoelectric conversion elements. And controlling each of the charge accumulation operations.

A thirteenth invention is a control method for controlling an operation of amplifying and reading out a signal of accumulated charges in a photoelectric conversion element comprising a plurality of pixels at a predetermined amplification factor. The method further includes a control step of reading control information of the provided memory and controlling the amplification factor based on the control information.

In a fourteenth aspect based on the thirteenth aspect, the control step is based on a monitor output step of monitoring and outputting the state of the accumulated charge in the photoelectric conversion element and control information read from the memory. A selection step of selecting arbitrary state information from a plurality of state information; a comparison step of comparing the monitor output by the monitor output step with the state information selected by the selection step; and a comparison step based on a comparison result of the comparison step. And a gain control step of controlling the gain.

In a fifteenth aspect based on the thirteenth aspect, the control step includes controlling each of the photoelectric conversion elements based on control information of a plurality of memories provided corresponding to the plurality of photoelectric conversion elements. Controlling each of the amplification factors for reading out the stored charge signal.

In a sixteenth aspect based on the eleventh or fourteenth aspect, the monitor output step includes a step of monitoring and outputting information based on the maximum accumulated charge amount of the photoelectric conversion element.

In a seventeenth aspect based on the eleventh or fourteenth aspect, the control step includes a step of storing the state information selected by the selection step in the memory as the control information. .

According to an eighteenth aspect based on the tenth or thirteenth aspect, the control step includes a step of determining predetermined information based on a signal of the stored charge read from the photoelectric conversion means; And storing the information determined in the determining step as the control information in the memory.

A nineteenth aspect of the present invention is directed to a focus detection device including the photoelectric conversion device according to any one of the first to ninth aspects.

According to a twentieth aspect, the present invention is a storage medium storing the processing steps of the control method according to any one of claims 10 to 18 in a computer readable manner.

[0045]

Embodiments of the present invention will be described below with reference to the drawings.

(1) First Embodiment

The photoelectric conversion device according to the present invention is applied, for example, to a photoelectric conversion device 100 as shown in FIG.

[0048] The photoelectric conversion device 100 is configured to enable multipoint AF, as shown in FIG. 1, a controller 1, a plurality of sensor array blocks 2 ₁ to 2 _n, and the level output circuit 3 , A buffer 4 with a selection signal, a comparator 5, and a read amplifier 6.

Further, a plurality of sensor row blocks 2 ₁ to 2 _n
Are provided corresponding to a plurality of distance measuring points (hereinafter, referred to as areas 1 to n), and have the same configuration. For example, the sensor array blocks 2 ₁ corresponding to the region 1 of the areas 1 to n includes an analog switch 11 ₁ and 12 _1,
A selection signal buffered 13 _1, the memory 14 _1, and a peak detection circuit 15 _1, a sensor 16 _1, and a RAM 17 _1.

First, each component of the photoelectric conversion device 100 as described above will be described.

(Controller 1) Controller
ler) 1 corresponds to a control means, which controls the operation of the entire apparatus,
In particular, it performs a charge accumulation control of each sensor array blocks 2 ₁ to 2 _n. Although details will be described later, the controller 1
Is provided with a program memory 18 in which processing programs for performing various operation controls are stored in advance.
When the processing program stored in the program memory 18 is read and executed by the controller 1, the operation control of the entire apparatus including the charge accumulation operation control is performed.

(Sensor Row Blocks 2 ₁ to 2 _n ) The sensor row blocks 2 ₁ to 2 _n correspond to photoelectric conversion means. Therefore, for example, in the sensor array block 2 _1, sensor 1
6 ₁ consists of a pair of sensor arrays for phase difference detection method is adapted to form two images 1 image, with the same number of pixels at about 30 to 80 pixels.

[0053] Peak detection circuit 15 ₁ corresponds to the monitor means, in the charge accumulation operation of the sensor 16 _1, (the output values of the pixels in the plurality of pixels, shows the highest output) the maximum accumulated charge amount detects and outputs it to the analog switch 12 _1. In this case, if the ON state by a signal psel_1 of the analog switch 12 ₁ is from the controller 1, the output signal p _out peak detecting circuit 15 ₁ via the analog switch 12 _1, the comparator 5 of the _one input terminal ( Output to the "+" terminal).

[0054] Memory 14 _1, the charge accumulation operation ends of the sensor 16 ₁ and at the same time, temporarily stores the charges accumulated in the sensor 16 ₁ as a pixel signal. In this case, if the ON state by the signal sel _1 from the analog switches 11 ₁ controller 1, the signal controller 1 outputs sh
ift By is given to the memory 14, the pixel signal s _out held in the memory 14 _1, the analog switch 11
Via ₁ , the data is sequentially output to the input terminal of the read amplifier 6.

[0055] RAM 17 ₁ corresponds to the storage unit, a memory for storing information (control information) about the charge accumulation of the sensor 16, a signal from the controller 1 LtcR_
When 1 is given, the value of the signal Rin from the level output circuit 3 described later is written. Further, when the signal rsel_1 is applied to the selection signal buffered 13 ₁ from the controller 1, the output signal Ro of the RAM 17 _1, as a signal r _out, is outputted through the selection signal buffered 13 _1.
The output signal r_out is provided to the read amplifier 6 and the level output circuit 3. Here, the signal r_out is
It is 2-bit data.

The other sensor row block 2_Two~ 2_nNitsu
In addition, the above-described sensor row block 2 ₁Same as
Therefore, the detailed description is omitted.

(Level Output Circuit 3) Level Output Circuit 3
Corresponds to a selection means or a determination means. For example, as shown in FIG. 2, three resistors r_1, r_2, r_3 and 4
One of the analog switches 21 to 24, an amplifier 25, a decoder 26, a selector 27, and a counter 28, the selector 27, the sensor array blocks 2 ₁ to 2
signal r _out selectively output from the _n (e.g., the sensor array block 2 _1, RAM 17 ₁ signal r _out output through the selection signal buffered 13 ₁ from) is applied, the output signal c of the amplifier 25 _Level and the output signal c_out of the counter 28 are output from the level output circuit 3. Here, the output signal c_out is 2-bit data.

In such a level output circuit 3, 3
The two resistors r_1, r_2, r_3 have two reference potentials v
ref1 and vref2, whereby the two reference potentials vref1 and vref2 are divided into four, and the four voltage values (level values as state information) level1.3, level
l1.2, level1.1, level1.0 are analog switches 21-
24 is output. At this time, any one of the analog switches 21 to 24 is turned on by the output of the decoder 26, and only the output of the turned on analog switch is output to the input terminal of the amplifier 25. This gives four level values level1.3, level1.2,
One of the level values of level1.1 and level1.0 is selected, and the selected level value is used as a signal c_level,
The signal is output from the amplifier 25.

The decoder 26 outputs the output signal of the selector 27
According to sel_out, four analog switches 21 to 2
4 is selected, and a signal for turning on the selected analog switch is output. Here, the output signal sel_out is 2-bit data.

[0060] The selector 27, that given the signal sel _level from the controller 1, the output signal c _out counter 28, any of the signals r _out selectively output from the sensor array block 2 ₁ to 2 _n And the selected signal is used as the signal sel_out, and the decoder 26
Output to

When the signal rst_level from the controller 1 is given to the counter 28, the count value is initialized to “0”, and the signal G__
When up is given, the count value is incremented. The count value of the counter 28 is the signal c_ou
t. Note that the signal max_level from the controller 1 given to the counter 28 will be described later.

(Buffer 4 with Selection Signal) The buffer 4 with selection signal has a signal c_out from the level output circuit 3.
(The count value of the counter 28), the buffer 4 with the selection signal is supplied from the controller 1 to the signal W_ra.
m By given, the signal c _out, and outputs a signal Rin is written in RAM 17 ₁ to 17 _n of sensor array blocks 2 ₁ to 2 _n.

(Comparator 5) The comparator 5 corresponds to comparing means, and outputs a signal c_leve from the level output circuit 3.
and l (the output of the amplifier 25), the sensor array blocks 2 ₁ to 2
signal p _out selectively output from the _n (e.g., the sensor array block 2 _1, the signal p _out output from the peak detecting circuit 15 ₁ via the analog switch 12 ₁₎
Is given. Then, the comparator 5 compares the signal c_level with the signal p_out, and outputs the comparison result to the controller 1 as a signal comp. still,
The output signal comp of the comparator 5 is the signal p_out
It becomes "1" when it is larger than c_level.

[0064] read amplifier 6 corresponds to the read means, the signal r is selectively output from the sensor array block 2 ₁ to 2 _n
_Out (e.g., the sensor array block 2 _1, RAM 1
7 ₁ from the signal r _out output via a selection signal buffered 13 _1), and a pixel signal s _out selectively output from the sensor array block 2 ₁ to 2 _n (e.g., the sensor array block 2 _1, pixel signal s _out output from the memory 14 ₁ via the analog switch 12 ₁₎ is given. Then, the read amplifier 6 outputs the pixel signal s_out
Is multiplied by a gain according to the signal r_out, and is output as a signal Vout.

The components of the photoelectric conversion device 100 have been described above. Next, the photoelectric conversion apparatus 100 overall operation control, in particular, will be specifically described controller 1 that performs a charge accumulation operation control in the sensor array block 2 ₁ to 2 _n. Note that the control method according to the present invention uses the controller 1
It is implemented by.

Therefore, for example, a processing program according to flowcharts as shown in FIGS. 3 to 5 is stored in advance in the program memory 18 of the controller 1,
By reading and executing these processing programs by the controller 1, the following charge accumulation operation control is performed.

(Main Processing: FIG. 3) First, the controller 1 performs the following reset processing (step S10).
1).

[0068] (Main Processing - reset processing: 4) First, the controller 1 outputs a reset signal rst the sensor 16 ₁ ~ 16 _n for each sensor array blocks 2 ₁ to 2 _n (step S201). Thus, the sensor 16 ₁ ~ 16 _n for each sensor array blocks 2 ₁ to 2 _n, the charge is cleared, the actual charge accumulation than now begins.

Next, the controller 1 has an internal register (not shown) for selecting a sensor row block (selecting an area).
Is set to the initial value "1" (step S202).

Next, the controller 1 outputs the signal max_leve
is output to the level output circuit 3 (step S2).
03). Thereby, the counter 28 of the level output circuit 3
Count value (signal c_out) becomes “3”.

Next, the controller 1 outputs the signal W_ram to the buffer 4 with a selection signal, and also selects the sensor row block 2x selected according to the register value r_sel.
The signal ltcR_x (x = 1 to n) is output to the RAM 17x (step S204). Where the register value r
Since _sel indicates a sensor row block (area) to be selected, it has a relationship of “x = r_sel”. Thereby, the sensor row block 2 corresponding to the register value r_sel
The output signal c_out (count value = "3") of the level output circuit 3 is written into the RAM 17x of x (x = r_sel = 1 to n).

Then, the controller 1 sets the register value r
_Sel is "n", that is, all the areas 1 to
Sensor row block 2 corresponding to area n₁~ 2_nRAM of
17 ₁~ 17_nTo determine whether "3" has been written to
(Step S205).

If the result of determination in step S205 is that writing has not been completed, the controller 1 sets the register value r_se
l is incremented (step S206), the process returns to step S204, and the subsequent processing is repeated. Thus, the RAM 17 ₁ to 17 _n all areas 1 n sensor arrays corresponding to the block 2 ₁ ~2 _n "3" is written. Thereafter, the process returns to the main process of FIG. 3 (step S207).

(Main Processing: FIG. 3) Step S1
01, the controller 1 then resets an internal timer (not shown) to an initial value “0” (timer
= 0), the time measurement of the charge accumulation operation is started (step S102).

Next, the controller 1 sets the register value r_sel of the internal register used in the above-described reset processing to the initial value "1" (step S103).

Next, the controller 1 determines whether or not the timer value timer of the internal timer has exceeded the maximum accumulation time Etime (step S104). As a result of this judgment, "time
If r ≧ Etime ”, step S109 to be described later
Proceed to.

As a result of the determination in step S104, "timer
If ≧ Etime ”, the controller 1 outputs a signal psel_x to the analog switch 12x of the sensor row block 2x selected according to the register value r_sel. The controller 1 also outputs the signal rsel_x to the sensor row block 2x. And the signal sel_level is output to the level output circuit 3x.
Is output (step S104). This allows
The output signal (maximum accumulated charge) of the peak detection circuit 15x of the sensor row block 2x is output to one input terminal ("+" terminal) of the comparator 5 as a signal p_out via the analog switch 12x. You. The output of the RAM 17x of the sensor array block 2x is supplied to the read amplifier 6 and the level output circuit 3 as a signal r_out via a buffer 13x with a selection signal. And
In the level output circuit 3, the signal r_ou is output by the selector 27.
t is selected, and the selected signal remains unchanged as the signal sel_out
To the decoder 26. The decoder 26 outputs the signal
According to sel_out, four level values level1.3, level
Select one of 1.2, level1.1, and level1.0. The selected level value is output via the amplifier 25 as a signal c_level.

Next, the controller 1 controls the comparator 5
Is not "1", that is, the output signal (level value) c_level of the level output circuit 3 is the output signal p__ of the peak detection circuit 15x of the sensor row block 2x.
It is determined whether it is larger than out (step S10).
6). If “comp = 1” as a result of this determination, the process proceeds to step S109 described below.

As a result of the determination in step S106, "comp =
If it is not 1 ", the controller 1 determines whether or not the timer value timer of the internal timer is the intermediate accumulation time Htime (step S107). As a result of this determination," time "
If it is not r = Htime ", step S described later
Proceed to 110. Here, this “timer = Htime”
Means that the timer value of the internal timer is the intermediate accumulation time
Htime is equivalent to the determination, and the time for which the gain determination operation described later can be completed in the entire area is sufficient.
timer = Htime ".

As a result of the determination in step S107, "timer
= Htime ", the controller 1 performs the following gain determination processing (step S108).

(Main Processing-Gain Discrimination Processing: FIG. 5) First, the controller 1 outputs a signal rst_level to the level output circuit 3 (step S301). As a result, in the level output circuit 3, the count value of the counter 28 is cleared to “0”, and the output signal c_out becomes “0”.
It is output as "0".

Next, the controller 1 controls the comparator 5
Is not "1", that is, the output signal c_level of the level output circuit 3 is
It is determined whether or not x is larger than the output signal p_out of the peak detection circuit 15x (step S302). If the result of this determination is not "comp = 1", the flow proceeds to the processing of step S305 described later.

As a result of the determination in step S302, "comp =
If it is "1", the controller 1 determines whether or not the output signal c_out of the level output circuit 3 is "3" (step S303). As a result of this determination, "c_out =
If it is 3 ", the process proceeds to step S305 described below.

As a result of the determination in step S303, "c_ou
If t = 3 ”is not satisfied, the controller 1 outputs the signal G_
is output to the level output circuit 3 (step S3).
04). Thereby, in the level output circuit 3, the count value (c_out) of the counter 28 is incremented. Thereafter, the process returns to step S302 described above, and the subsequent processing is repeated.

In step S302, “comp =
If it is determined that it is not “1”, or step S303
When the controller 1 determines that “c_out = 3”, the controller 1 outputs the signal W_ram to the buffer 4 with the selection signal and the RAM of the sensor array block 2x.
Output signal ltcR_x for x (step S30)
5). Thereby, the RAM 17 of the sensor row block 2x is
In x, the output signal c_out of the level output circuit 3 is written. After this process, the process returns to the main process of FIG. 3 (step S306).

Here, as described above, in this gain determination processing, the peak detection circuit 15x of the sensor row block 2x
Is determined on the basis of the output signal p_out of the read amplifier 6, that is, the level (the output signal c_level of the level output circuit 3) at which the charge accumulation operation is completed is determined.
The count value (c_out) corresponding to the level is written in the RAM 17x of the sensor row block 2x. The count value (c_out), that is, the count value of the counter 28 of the level output circuit 3 is counted up one by one from the initial value “0”, and accordingly, the output signal c_level of the level output circuit 3 is also increased. , From “level1.0” to “level”
The level gradually rises from "1.1" to "level1.1" to "level1.2".

Therefore, first, “level1.0” and “comp”
When = 1 does not occur, it means that the output signal p_out of the peak detection circuit 15x is lower than "level1.0", so that the level at which the charge accumulation operation ends is determined to be "level1.0", and is stored in the RAM 17x. Is written with a count value (c_out = 0) corresponding to the level.
After "comp = 1" in "vel1.0", "level1.1"
If comp = 1 is not satisfied, it means that the output signal p_out of the peak detection circuit 15x is between "level1.0" and "level1.1", and the level at which the charge accumulation operation ends is "level1. 1 ", and the count value (c_out = 1) corresponding to the level is written into the RAM 17x. Similarly, the output signal p_out is changed to" level1.
When it is between “1” and “level1.2”, it is determined to be “level1.2” and the output signal p_out is “level1.2” and “level1.
When it is between "3", it is determined to be "level1.3", and the corresponding count values (c_out = 2, 3) are written.

(Main Processing: FIG. 3) On the other hand, Step S1
If the result of the determination in step 04 is “timer ≧ Etime” (when the timer value of the internal timer exceeds the maximum accumulation time Etime), or the result of the determination in step S106 is “comp”
= 1 "(when the output signal (level value) c_level of the level output circuit 3 exceeds the output signal p_out of the peak detection circuit 15x of the sensor row block 2x).
The controller 1 terminates the charge accumulation operation, and outputs a signal trans indicating this to the sensor 16x of the sensor row block 2x (step S109). Thereby, in the sensor row block 2x corresponding to the region x, the sensor 16x
The charges accumulated in each pixel are transferred to the memory 14x as pixel signals, and the charge accumulation operation in the sensor 16x ends.

After the processing in step S109, or after the above-described gain determination processing (step S108), or when "timer = Htime" is not satisfied (the timer value timer of the internal timer does not exceed the intermediate accumulation time Htime). Time), the controller 1 sets the register value r of the internal register
_Sel is "n", that is, all the areas 1 to
The sensor column block 2 ₁ to 2 _n corresponding to the area n, it is determined whether or not subjected to the processing in steps S104 to S109 (step S110).

As a result of the determination in step S110, "r
_Sel = n "if a was the controller 1, in order to cover the sensor array block 2 _of the early region 1, the register value r _sel internal registers" 1 back to ", the processing from step S104 Repeat "r_
If sel = n ″ is not satisfied, the controller 1 increments the register value r_sel of the internal register to target the sensor array block 2 _{x + 1} in the next area (x + 1), and then proceeds to step S104. Are repeated.

[0091] The foregoing has described a charge accumulation operation control in the sensor array block 2 ₁ to 2 _n by the control 1. Therefore, with reference to FIGS. 6 (A) and 6 (B), illustrating the operation of the sensor array blocks 2 ₁ to 2 _n by the charge accumulation operation control described above schematically below.

In FIGS. 6A and 6B, the horizontal axis represents the charge accumulation operation time, and the vertical axis represents the output signal c_level of the level output circuit 3 and the peak detection circuit 15x of the sensor row block 2x. It indicates the value of the output signal p_out. FIG. 6A shows that the subject is relatively bright,
Peak output of each pixel signal, that is, sensor row block 2
6B shows a case where the output signal p_out of the x peak detection circuit 15x rises quickly. In contrast to this, FIG. 6B shows that the subject is relatively dark and the peak output of each pixel signal rises slowly. Shows the case.

[0093] (in the case of FIG. 6 (A)) First, the charge accumulation operation is started, the RAM 17 ₁ to 17 _n all areas 1 n sensor array blocks 2 ₁ to 2 _n corresponding to "
3 "is written, the output signal of the level output circuit 3 is output.
c_level is “level1.3”. Then, when the output signal p_out of the peak detection circuit 15x of the sensor row block 2x in a certain area x reaches this "level1.3" (P
At the point _A), the charge accumulation operation in the sensor row block 2x ends. The same applies to the sensor row blocks corresponding to other areas.

(Case of FIG. 6B) First, the charge accumulation operation
Is started, the sensors corresponding to all the areas 1 to n are started.
Sub row block 2₁~ 2_nRAM 17₁~ 17_nTo
3 "is written, the output signal of the level output circuit 3 is output.
c_level is “level1.3”. Where in this case
, The peak output (p_out) of each pixel signal rises slowly
The charge storage operation time (internal
Ima's timer value timer) has reached the intermediate storage time Htime
At this time (P_B1 point), the gain determination process (step
Step S108) is performed, and the sensor corresponding to each of the areas 1 to n is performed.
Sub row block 2₁~ 2 _nTo the end of the charge accumulation operation
The bell (c_level) is determined. In FIG. 6 (B)
Is the peak detection time of the sensor row block 2x in a certain area x.
The output signal p_out of the path 15x is “level1.1” and “level
l1.2 ", the sensor row block 2x
Therefore, c_level is determined to be “level1.2” and this information
(In this case, "c_out = 2") is stored in the RAM 17x.
Is written to. And the output of the peak detection circuit 15x
When the signal p_out reaches “level1.2” (P_B2
Point), the charge storage operation in the sensor row block 2x is
finish. Note that sensors corresponding to areas other than the area x
Similarly, for the sub-row blocks, the charge accumulation operation ends.
The level is determined, the information is written to RAM, and the
The peak output reaches the specified level at the end of the charge storage operation.
The charge accumulation operation in that sensor row block ends.
Complete.

As described above, in the present embodiment,
Sensor row blocks 21 to 2 corresponding to all areas ₁ to n
_n of the RAMs 17 _{1 to} 17 _n stores information on the charge storage operation (here, the level (c
Since the value (c_out)) corresponding to _level) is written, the charge storage operation of the sensor row blocks 21 to 2n corresponding to the regions ₁ to _n can be controlled independently. In addition, since an operation such as counting up is not performed immediately after the start of the charge accumulation operation even for a high-brightness object as in the related art, the image signal of the object exceeds the dynamic range, resulting in image distortion. There is no problem. Therefore, even if the number of distance measurement points of the multipoint AF increases, appropriate charge accumulation operation control can always be performed, and the inexpensive photoelectric conversion device 100 that is highly accurate and does not require a large circuit scale can be provided. .

(2) Second Embodiment In this embodiment, for example, in the photoelectric conversion device 100 according to the above-described first embodiment, the read operation of the pixel signal by the read amplifier 6 is controlled as follows. To

Therefore, a processing program according to the flowchart shown in FIG. 7 is stored in the program memory 18 of the controller 1 in advance, and the processing program is read out and executed by the controller 1, so that The following read control is performed.

First, the controller 1 selects a region from which pixel signals are read (here, the region x (x = 1 to x = 1)).
n)), and the value (= x) corresponding to the area x is stored in the internal register. Then, the controller 1 outputs a signal
sel_x is the analog switch 1 of the sensor array block 2x
Output for 1x. As a result, in the sensor row block 2x, the pixel signal s_ held in the memory 14x is output.
It is ready to sequentially output out to the input terminal of the read amplifier 6 via the analog switch 11x. Further, the controller 1 outputs the signal psel_x to the analog switch 12x of the sensor row block 2x. Thereby, in the sensor row block 2x, the peak detection circuit 1
The 5x output signal p_out is supplied to one input terminal ("+" terminal) of the comparator 5 via the analog switch 12x.
(Step S401).

Next, the controller 1 performs the gain determination processing shown in FIG. Thereby, the sensor row block 2x
(The output signal c_level of the level output circuit 3) is determined based on the output signal p_out of the peak detection circuit 15x, and the count value (c_out) corresponding to the level is determined.
) Is written into the RAM 17x of the sensor row block 2x (step S402).

Then, the controller 1 outputs the signal shift to the memory 14x of the sensor row block 2x. As a result, the pixel signal s held in the memory 14x is
_Out is sequentially output to the input terminal of the read amplifier 6 via the analog switch 11x. Further, the controller 1 outputs the signal rsel_x to the buffer 13x with the selection signal of the sensor row block 2x. As a result, the value (c_out) written to the RAM 17x is read as a signal Ro, and is output to the read amplifier 6 as a signal r_out via the buffer 13x with a selection signal. Therefore, the read amplifier 6 is connected to the memory 14x
Is multiplied by a gain based on the signal r_out, for example, a gain selected in accordance with the signal r_out from a plurality of preset gains, to the output terminal Vo.
Output from ut (step S403).

As described above, in the present embodiment,
Immediately before the pixel signal is read out, the gain determination process (level determination at the end of the charge accumulation operation) as shown in FIG. 5 is performed. For example, the charge accumulation operation time is set to a fixed time in moving object prediction AF or the like. By doing so, even if the gain determination processing cannot be performed during the charge accumulation operation, the gain determination processing is performed immediately before reading out the pixel signal, and the pixel signal is read out using the gain of the processing result. Therefore, it is possible to provide a more accurate photoelectric conversion device 100 that always reads an appropriate pixel signal.

Note that the present invention is not limited to the application to the AF camera and the like described above, but can be applied to, for example, various devices having a focus detection function.

In the first and second embodiments described above, the output of the peak detection circuit is used for the gain discrimination processing. However, the present invention is not limited to this. A so-called peak-bottom signal obtained by calculating the difference between the outputs may be used.

In the second embodiment, the first
In this embodiment, when the gain cannot be determined for some reason, an application is conceivable in which a gain determination operation is performed immediately before reading. The "reason for any reason" here means, for example, that the maximum accumulation time Etime is short. If the gain output is determined using a peak and bottom differential output circuit instead of the peak detection circuit, the peak output is This is, for example, when an operation for terminating the accumulation is performed because the predetermined level has been exceeded.

[0105] Further, as the sensor 16 ₁ ~ 16 _n of sensor array blocks 2 ₁ to 2 _n, for example, CCD and CMOS
Any sensor such as a sensor may be used.

The RA of the sensor row blocks 2 ₁ to 2 _n is
The M17 ₁ to 17 _n, for example, may be a digitally memory, it may be analog memory.

Further, an object of the present invention is to provide a storage medium storing program codes of software for realizing the functions of the host and the terminal of the first and second embodiments.
It is needless to say that the present invention is also achieved by supplying the data to a system or an apparatus, and reading and executing a program code stored in a storage medium by a computer (or CPU or MPU) of the system or the apparatus. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention.

As storage media for supplying the program code, ROM, floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, C
DR, a magnetic tape, a nonvolatile memory card, or the like can be used.

By executing the program code read by the computer, not only the functions of the above-described first and second embodiments are realized, but also the computer executes the program code based on the instructions of the program code. It goes without saying that the operating OS or the like performs part or all of the actual processing, and the functions of the embodiments are realized by the processing.

Further, after the program code read from the storage medium is written into a memory provided in an extension function board inserted into the computer or a function extension unit connected to the computer, based on the instructions of the program code, The CPU provided in the function expansion board or function expansion unit performs part or all of the actual processing,
It goes without saying that the processing may realize the functions of the first and second embodiments.

[0111]

As described above, according to the present invention, storage means (such as a memory capable of writing and reading information) corresponding to a photoelectric conversion element is provided, and control information read from the storage means is stored in the storage means. Based on the above, the charge accumulation operation (start and end of the charge accumulation operation, etc.) in the photoelectric conversion element and the amplification factor (gain) at the time of reading out the pixel signal are controlled, so that a subject having any luminance level can be controlled. An appropriate charge accumulation operation can always be performed, and a pixel signal can always be read with an appropriate gain. In particular, even when there are many ranging points in a multi-point autofocus camera, etc., appropriate charge accumulation operation can always be performed, and pixel signals can always be read out with an appropriate gain. It is possible to read out a pixel signal that is effectively used without any loss, to perform high-precision autofocusing, and to provide a low-cost circuit without increasing the circuit scale. Also, by integrally forming the photoelectric conversion element and the storage means corresponding thereto on the same substrate,
Control efficiency can be improved, and even if the number of distance measurement points is large, the circuit scale does not become enormous, and the cost can be further reduced and the operability can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a photoelectric conversion device to which a photoelectric conversion device according to the present invention is applied in a first embodiment.

FIG. 2 is a block diagram showing a configuration of a level output circuit of the photoelectric conversion device.

FIG. 3 is a flowchart for describing a charge accumulation operation control processing program (main processing) executed by a controller of the photoelectric conversion device.

FIG. 4 is a flowchart for explaining a reset processing program of the charge accumulation operation control processing program.

FIG. 5 is a flowchart for explaining a gain determination processing program of the charge accumulation operation control processing program.

FIG. 6 is a diagram schematically illustrating a charge accumulation operation in the photoelectric conversion device.

FIG. 7 is a flowchart for describing a pixel signal readout operation control processing program executed by a controller of the photoelectric conversion device in the second embodiment.

FIG. 8 is a block diagram illustrating a configuration of a conventional photoelectric conversion device.

FIG. 9 is a flowchart illustrating a conventional charge accumulation operation control process.

FIG. 10 is a diagram for schematically explaining a charge accumulation operation in a conventional photoelectric conversion device.

[Explanation of symbols]

REFERENCE SIGNS LIST 100 photoelectric conversion device 1 controller 2 ₁ to 2 _n sensor row block 3 level output circuit 4 buffer with selection signal 5 comparator 6 readout amplifier 11 ₁ analog switch 12 ₁ analog switch 13 ₁ buffer with selection signal 14 ₁ memory 15 ₁ peak detection circuit 16 ₁ sensor 17 ₁ RAM 18 program memory

Claims (20)

[Claims] 1. A photoelectric conversion unit including a photoelectric conversion element composed of a plurality of pixels and a storage unit for storing predetermined control information, and a charge accumulation operation in the photoelectric conversion unit based on the control information stored in the storage unit. And a control unit for controlling the photoelectric conversion. 2. The photoelectric conversion means further includes a monitor means for monitoring and outputting a state of accumulated charge in the photoelectric conversion element, and the control means includes a plurality of states based on control information stored in the storage means. Selecting means for selecting any state information from the information; and comparing means for comparing the output of the monitor means with the state information selected by the selecting means, and the photoelectric conversion means based on a comparison result of the comparing means. 2. The photoelectric conversion device according to claim 1, wherein the charge storage operation is controlled by the device. 3. A photoelectric conversion means including a photoelectric conversion element comprising a plurality of pixels and a storage means for storing predetermined control information, and a reading means for amplifying and reading out a signal of a charge accumulated in the photoelectric conversion element at a predetermined amplification factor. And a control means for controlling an amplification factor in the reading means based on the control information stored in the storage means. 4. The photoelectric conversion unit further includes a monitor unit for monitoring and outputting a state of the accumulated charge in the photoelectric conversion element, and the control unit controls a plurality of states based on control information stored in the storage unit. Selecting means for selecting any state information from the information; and comparing means for comparing the output of the monitor means with the state information selected by the selecting means, wherein the reading means based on a comparison result of the comparing means. The photoelectric conversion device according to claim 3, wherein the amplification factor is controlled. 5. The photoelectric conversion device according to claim 1, comprising a plurality of said photoelectric conversion means. 6. The photoelectric conversion device according to claim 2, wherein said monitoring means monitors and outputs information based on a maximum accumulated charge amount of said photoelectric conversion element. 7. The photoelectric conversion device according to claim 2, wherein the control unit stores the state information selected by the selection unit in the storage unit as the control information. 8. The photoelectric conversion device according to claim 1, wherein the photoelectric conversion unit includes the photoelectric conversion element and the storage unit formed on the same substrate. 9. The control means includes a determination means for determining predetermined information based on a signal of the stored charge read from the photoelectric conversion means, and uses the information determined by the determination means as the control information. The photoelectric conversion device according to claim 1, wherein the photoelectric conversion device is stored in the storage unit. 10. A control method for controlling a charge storage operation in a photoelectric conversion element comprising a plurality of pixels, comprising reading out control information of a memory provided corresponding to the photoelectric conversion element, based on the control information. A control method including a control step of controlling a charge accumulation operation in the photoelectric conversion element. 11. The control step includes: a monitor output step of monitoring and outputting a state of accumulated charges in the photoelectric conversion element; and selecting arbitrary state information from a plurality of state information based on the control information read from the memory. A comparing step of comparing the monitor output by the monitor output step with the state information selected by the selecting step; and controlling a charge accumulation operation in the photoelectric conversion element based on a comparison result of the comparing step. The control method according to claim 10, further comprising a storage operation control step. 12. The control step includes a step of controlling a charge storage operation of each photoelectric conversion element based on control information of a plurality of memories provided corresponding to the plurality of photoelectric conversion elements. 11. The method according to claim 10, wherein
The control method described. 13. A control method for controlling an operation of amplifying and reading out a signal of an accumulated charge in a photoelectric conversion element including a plurality of pixels at a predetermined amplification factor, and comprising a memory provided corresponding to the photoelectric conversion element. A control method of reading out the control information of the above and controlling the amplification factor based on the control information. 14. The control step includes: a monitor output step of monitoring and outputting a state of accumulated charges in the photoelectric conversion element; and selecting arbitrary state information from a plurality of state information based on the control information read from the memory. A comparing step of comparing the monitor output by the monitor output step with the state information selected by the selecting step; and an amplification factor controlling step of controlling the amplification factor based on a comparison result of the comparing step. The control method according to claim 13, further comprising: 15. The amplification step of reading a signal of a stored charge in each photoelectric conversion element based on control information of a plurality of memories provided corresponding to the plurality of photoelectric conversion elements. 14. The control method according to claim 13, further comprising the step of controlling 16. The method according to claim 11, wherein the monitor output step includes a step of monitoring and outputting information based on a maximum accumulated charge amount of the photoelectric conversion element.
5. The control method according to 4. 17. The control method according to claim 11, wherein the control step includes a step of storing the state information selected in the selection step as the control information in the memory. 18. The control step according to claim 1, wherein the determining step determines predetermined information based on a signal of the stored charge read from the photoelectric conversion unit, and the information determined in the determining step is used as the control information as the control information. Storing the data in a memory.
14. The control method according to 0 or 13. 19. A focus detection device comprising the photoelectric conversion device according to claim 1. Description: 20. A storage medium, wherein the processing steps of the control method according to claim 10 are readable by a computer.