JP2003232630A - Distance measuring device and camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent leakage of the charge caused by the incoming light from the chip side, in a photoelectric transfer device formed on a semiconductor chip. <P>SOLUTION: The A/D conversion is executed preferentially from a pixel signal in a sensor array nearer to the side of the chip, the light receiving means. If the level of the brightness of an object of measurement is high, the sensor array is divided into a plurality of regions, and the accumulation of the charge and the A/D conversion are executed by region. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring device using a light receiving means composed of a plurality of photoelectric conversion elements for measuring a distance to a measuring object.

[0002]

2. Description of the Related Art Various proposals have been made for a charge storage type photoelectric conversion device, and also a distance measuring device to which the photoelectric conversion device is applied.

In a distance measuring device to which a photoelectric conversion device is applied, generally, a plurality of photoelectric conversion elements are arranged at a predetermined pixel pitch in the photoelectric conversion device, and a charge storage section and charge storage corresponding to each photoelectric conversion element are provided. A control circuit and a circuit for reading out photoelectric output are formed on one semiconductor chip.

FIG. 7 shows a schematic view of the distance measuring device as described above.

In FIG. 7, 201 is a first light receiving lens which forms a first optical path, and 202 is a second light receiving lens which forms a second optical path.

Reference numeral 203 is a first sensor array in which a plurality of photoelectric conversion elements are linearly arranged, 204 is a second sensor array having the same structure as the first sensor array 203, and 205 is a first signal storage. The electric charge photoelectrically converted by the first sensor array 203 in accordance with the ST pulse is converted into a voltage and accumulated in each pixel. Further, the signal storage unit 205 clears the signal stored according to the RES pulse. Reference numeral 206 denotes a second signal accumulating unit, which converts the charges photoelectrically converted by the second sensor array 204 into a voltage and accumulates it for each pixel in the same manner as the first accumulating unit, and accumulates according to the RES pulse. Clear the signal.

Reference numeral 207 denotes a peak detection unit, which detects the output having the largest signal storage amount from the pixels of the first signal storage unit 205 and the second signal storage unit 206, and follows this output. The signal is output as a PKMON signal. Reference numeral 210 denotes a first signal output unit, which sequentially outputs a signal corresponding to each pixel of the first signal storage unit as an OUT signal by the CLK1 pulse. Reference numeral 211 denotes a second signal output unit, which similarly to the first signal output unit 210, sequentially outputs a signal corresponding to each pixel of the second signal storage unit as an OUT signal by the CLK2 pulse.

Sensor arrays 203 and 204, signal accumulators 205 and 206, peak detector 207, signal output unit 2
The photoelectric conversion device 200 is configured by 10,211.

FIG. 8 is a timing chart showing the accumulating operation and the signal reading operation of the distance measuring device of FIG.

First, the signals in the first signal storage section 205 and the second signal storage section 206 are cleared by changing the RES pulse from L to H. Then, after a predetermined time, the RES pulse is changed from H → L and the ST pulse is changed from H → L to permit signal accumulation, and the accumulation operation is started.

During the storage operation, the voltage level of the signal storage section drops with an inclination according to the amount of incident light for each pixel of the sensor array. That is, the larger the amount of light incident on the pixel, the lower the voltage level of the signal storage unit. The output indicating the peak level of the pixel is the lowest output of the signal accumulation levels corresponding to each pixel (that is, the output of the pixel with the largest signal accumulation amount).
, And is output from the PKMON signal as a monitor signal.

The PKMON signal level is A / D converted by an A / D conversion converter built in a control unit (not shown), and the level is checked.

When the accumulated amount reaches an appropriate level,
By changing the ST pulse from L to H, the first signal storage unit 2
05 and the second signal storage unit 206 ends the storage operation, and simultaneously holds the storage signal level of each pixel.

After the accumulation operation is completed, the accumulation signal is read out. Here, when a CLK1 pulse is first input as a read clock, the signal of each pixel of the first sensor array 203 is sequentially output to OUT. First sensor array 2
When the output of all the pixel signals of 03 is completed, the CLK2 pulse is input, and the signal of each pixel of the second sensor array 204 is sequentially output to OUT.

Further, a control unit (not shown) A / D-converts the output signal in synchronization with the CLK pulse to perform RA in the internal control unit.
The data is stored in M, and the read operation is terminated when the reading of the accumulated signals for all the pixels is completed.

As described above, the first sensor array 203
The distance to the object to be measured by the principle of triangulation based on the relative value of the image signal of the object to be measured obtained above and the image signal of the object to be measured obtained on the second sensor array 204. Ask for.

[0017]

FIG. 9 shows the luminance distribution on the sensor arrays 203 and 204 of the distance measuring device shown in FIG. In FIG. 9, the signal level is shown to increase as the intensity of the received light intensity increases. The sensor array 203 is L1 to L10, and the sensor array 204 is R1.
To R10 photoelectric conversion elements. The figure (a) is an image signal on the sensor array 203, and the figure (b) is an image signal on the sensor array 204. In the same figure (a), L3 to L
The received light image is formed over 7 points, and in (b),
An image of the received light is formed across R4 to R8.

FIG. 10A, FIG. 10B, FIG. 10A ′, and FIG. 10B ′ show the timings of capturing the output of each pixel and the signal output waveform after accumulating the signals as shown in FIG. FIGS. 10A and 10B show ideal image signal waveforms, and FIGS. 10A and 10B show charges generated by light incident on the side surface of the photoelectric conversion device in the signal storage unit. This is the waveform when it leaks. The shaded area in FIG. 10 (b ') is
The amount of electric charge increased by the light leaked from the side surface of the chip is shown.

Usually, the photoelectric conversion device is formed on a semiconductor chip and is shielded by a light shielding material such as aluminum so that light does not enter the surface of the chip except the sensor array, but the side surface of the chip is not shielded. .

In this case, the higher the brightness of the object to be measured and its surroundings, and the later the timing of A / D conversion after the end of the accumulation operation, the more unnecessary charges are accumulated. Further, since the charge leaks from the side surface of the chip, pixels closer to the side surface of the chip are more likely to be affected by unnecessary charges.

10 (a ') and 10 (b') are different in the amount of leakage of electric charges from the pixel L1 of the sensor array 203.
Side and the pixel R10 side of the sensor array 204 are close to the side surface of the chip, the charge easily leaks.
The pixel L10 side of 3 and the pixel R1 side of the sensor array 204 are less likely to leak charges, and also output a signal (A
The order of (/ D conversion) is from the pixel L1 of the sensor array 203 to the pixel R10 of the sensor array 204, and the pixels on the L1 side where the time from the end of accumulation to A / D conversion is short have almost no leakage of charges. This is because. On the contrary, R10 of the sensor array 204 takes a long time from the end of the accumulation to the A / D conversion, so that the amount of leakage of electric charges increases. This charge leakage occurs even during signal storage, but at a brightness where the amount of leakage affects the signal, the storage time is generally short, so the leakage during signal storage can be ignored.

Further, in order to reduce the influence of the charge leakage due to the incident light from the side surface of the chip, there is a method in which the distance from the signal storage portion to the chip end is sufficiently separated, but the chip area is large. Therefore, there is a problem that the cost becomes high.

Further, Japanese Unexamined Patent Publication No. 9-229673 discloses a distance measuring device using a light receiving means including a plurality of photoelectric conversion elements, wherein a transfer stage C is formed by a dark current component or an external light component.
It has been proposed to correct the distortion of the image signal due to the gradual charge leakage into the CD (ring CCD, etc.), but the charge leakage due to the incident light from the side surface of the chip causes only the pixels near the side surface of the chip to charge. However, it cannot be solved by the method described in the above publication.

According to the present invention, the photoelectric conversion device is constructed in a small size,
An object of the present invention is to obtain a distance measuring device which can reduce the cost and can also reduce the deterioration of the distance measuring accuracy due to the influence of charges leaking from the side surface of the chip.

[0025]

In order to solve the above-mentioned problems, the invention according to claim 1 of the present application has a plurality of photoelectric conversion elements arranged on a semiconductor chip for receiving an image of an object to be measured. A photoelectric conversion element array, a signal storage means for storing the charges converted by the photoelectric conversion element array, a signal output means for outputting a signal according to the amount of charges stored by the signal storage means, and the signal output means Of the output of
A / D conversion means for preferentially A / D converting a signal corresponding to a photoelectric conversion element in the vicinity of the chip end, and a distance to the distance measurement object based on the signal converted by the A / D conversion means The distance measuring device is provided with a distance calculating means for calculating

Similarly, in order to solve the above-mentioned problems, the invention according to claim 4 of the present application is a photoelectric conversion element array provided on a semiconductor chip for receiving an image of an object to be measured, and the photoelectric conversion element array. A signal accumulating means for accumulating the converted charges, a signal outputting means for outputting a signal according to the amount of charges accumulated by the signal accumulating means, and an A / D converting the output from the light receiving means for A / D conversion. In a distance measuring device including a converting means and a distance calculating means for calculating distances to the plurality of distance measuring objects based on the A / D converted signals, the luminance of the distance measuring object is at a predetermined level. If the size of the region of the photoelectric conversion element array that performs A / D conversion after simultaneously accumulating charges is different according to the determination result of the brightness determining unit, the brightness determining unit determines whether or not the above is satisfied. Characterized by Than it is.

Further, the camera has these distance measuring devices.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a block diagram of a distance measuring device according to the present invention. Descriptions of the same reference numerals as those in FIG. 7 are omitted.

In FIG. 1, reference numeral 208 denotes a first signal output section, which outputs a signal corresponding to each pixel of the first signal storage section,
It is sequentially output as an OUT signal by the CLK1 pulse.
209 is a second signal output unit, and the first signal output unit 2
Similar to 08, a signal corresponding to each pixel of the second signal storage section is sequentially output as an OUT signal by the CLK2 pulse. As shown in FIG. 9, the first sensor array 203
Has pixels L1 to L10, and the second sensor array 204 has pixels R1 to R10.

Here, the first signal output unit 208 outputs CLK
L1 → L2 → L3 → ・ ・ ・ → L9 → L1 by 1 pulse
The circuit is configured to output in the order of 0, while the second signal output unit 209 outputs R10 → R9 → by the CLK pulse 2.
The circuit is configured to output in the order of R8 → ... → R2 → R1.

FIG. 2 is a timing chart showing a signal reading operation of the distance measuring device of FIG. The accumulation operation is the same as that described with reference to FIG.

After the accumulation operation is completed, the accumulation signal is read out.

Here, when the CLK1 and CLK2 pulses are input as the read clock, the signal of each pixel is sequentially output as the OUT signal.

At this time, by alternately inputting the CKL1 pulse and the CLK2 pulse for each pulse, the output order is L1.
→ R10 → L2 → R9 → L3 → R8 → ・ ・ ・ → L9 → R
2 → L10 → R1. That is, by preferentially outputting the signal from the pixel closer to the side surface of the chip and performing A / D conversion, the time timing from the end of accumulation to the A / D conversion of the pixel closer to the chip side surface becomes shorter. Therefore, the A / D conversion can be completed before the charges generated by the incident light from the side surface of the chip leak into the signal storage section.

(Second Embodiment) FIG. 3 is a block diagram of a distance measuring device according to a second embodiment of the present invention.

In FIG. 3, reference numeral 701 is a first light receiving lens forming a first optical path, and 702 is a second light receiving lens forming a second optical path.

Reference numeral 700 denotes a photoelectric conversion device, which is composed of sensor arrays 703, 704, signal storage units 705, 706, peak detection unit 707, and signal output units 708, 709.

Reference numeral 703 is a first sensor array in which a plurality of photoelectric conversion elements are linearly arranged, and 704 is a second sensor array. Sensor arrays 703 and 704
Are each divided into three areas. Correspondences between pixels and areas of the sensor arrays 703 and 704 divided into three areas will be described with reference to FIG.

In FIG. 4, the pixels L1 to L5 of the sensor array 703 receive the image from the object to be measured located to the right by the first light receiving lens 701, and the pixels R1 to R5 of the sensor array 704 are the second. The light receiving lens 702 receives the image from the object to be measured located to the right. Similarly, the pixels L6 to L10 of the sensor array 703 receive the image from the distance measuring object located in the center direction by the first light receiving lens 701, and the pixels R6 to R10 of the sensor array 704 are the second light receiving lens. 702 receives an image from an object to be measured located in the central direction. The pixels L11 to L15 of the sensor array 703 are the first light receiving lens 7
01 receives the image from the object to be measured positioned to the left, and the pixels R11 to R15 of the sensor array 704 are set to the second pixel.
The light receiving lens 702 receives the image from the object to be measured located to the left.

In FIG. 3, reference numeral 705 denotes a first signal storage section,
Reference numeral 706 denotes a second signal storage unit, which converts the charges photoelectrically converted by the pixels L1 to L5 of the first sensor array 703 and the pixels R1 to R5 of the second sensor array 704 into voltage by the ST1 pulse Accumulate in. Also, ST
The pixel L6 of the first sensor array 703 is generated by two pulses.
To L10 and pixels R6 to R of the second sensor array 704
The charge photoelectrically converted in 10 is converted into a voltage and accumulated for each pixel, and the first sensor array 703 is generated by the ST3 pulse.
The pixels L11 to L15 and the pixels R11 to R15 of the second sensor array 704 are converted into voltage and accumulated in each pixel. Further, the signals accumulated in the signal accumulating units 705 and 706 can be cleared by the RES pulse.

Reference numeral 707 denotes a peak detection unit, which detects the output having the largest signal storage amount from the pixels of the first signal storage unit 705 and the second signal storage unit 706, and follows this output. The signal is output as a PKMON signal.

Reference numeral 708 denotes a first signal output section, which sequentially outputs the signals stored in the first signal storage section 705 and corresponding to each pixel of the first sensor array 703 as OUT signals by CLK1 to 3 pulses. . Reference numeral 709 denotes a second signal output unit, which sequentially outputs signals corresponding to each pixel of the second sensor array 704 stored by the second signal storage unit 706 as OUT signals by CLK4 to 6 pulses.

The CLK1 pulse has L1 to L5 of the first sensor array 703, the CLK2 pulse has L6 to L10 of the same sensor array, and the CLK3 pulse has L11 to L1.
The circuit is configured so as to output a signal corresponding to 5. The second sensor array 7 is used for the CLK4 pulse.
The circuit is configured so as to output signals corresponding to R6 to R10 of the same sensor array and R11 to R15 of the same sensor array for the R1 to R5 and CLK5 pulses of 04.

The operation of the distance measuring device shown in FIG. 3 will be described with reference to the flowchart shown in FIG.

[# 901] The signals in the first signal storage section 705 and the second signal storage section 706 are cleared by changing the RES pulse from L to H. And after a predetermined time R
The ES pulse is changed from H to L, and ST1 and ST2, ST3
By setting all the pulses from H to L, signal accumulation of all pixels of the first and second sensor arrays is permitted, and the accumulation operation is started.

[# 902] The PKMON signal level output from the peak detection unit 707 is A / D converted by an A / D conversion converter incorporated in the control unit (not shown), and the level is checked to store the signal. Accumulation is continued until the amount reaches a predetermined level.

When the accumulated amount reaches an appropriate level, the process proceeds to the next step # 903.

[# 903] By changing the ST pulse from L to H, the accumulation operation in the first signal accumulating section 705 and the second signal accumulating section 706 is completed, and at the same time, the accumulated signal level of each pixel is held. To do.

[# 904] The signal reading operation is started.

First, CLK1 is input as a read clock, and the pixels L1 to L5 of the first sensor array 703 are input.
Signals are sequentially output as OUT signals.

At this time, a control unit (not shown) performs A / D conversion in synchronism with the CLK1 pulse and stores it in a predetermined address of the RAM in the internal control unit to read the accumulated signal for the pixels L1 to L5. .

[# 905] Read clock CLK6
Is input, and the pixels R11 to R11 of the second sensor array 704 are input.
The read operation is performed for the signal of R15 in the same manner as in step # 904.

[# 906] Read clock CLK2
Is input to pixels L6 to L of the first sensor array 703.
The read operation is performed for the signal of 10 as in step # 904.

[# 907] Read clock CLK5
Is input to pixels R6 to R of the second sensor array 704.
The read operation is performed for the signal of 10 as in step # 904.

[# 908] Read clock CLK3
, And the pixels L11 to L11 of the first sensor array 703.
The read operation is performed for the signal of L15 as in step # 904.

[# 909] Read clock CLK4
Is input to the pixels R1 to R of the second sensor array 704.
The read operation is performed for the signal of No. 5 as in Step # 904.

[# 910] An image signal is formed from the signals of the pixels L1 to L5 read in step # 904 and the signals of the pixels R1 to R5 read in step # 909, and triangulation is performed based on the relative value of the image signal. According to the principle of distance, the distance to the object to be measured in the right direction is calculated.

Similarly, an image signal is formed from the signals of the pixels L6 to L10 read in step # 906 and the signals of the pixels R6 to R10 read in step # 907, and triangulation is performed based on the relative value of the image signal. The distance to the object to be measured in the center direction is obtained according to the principle of the above, and the signals of the pixels L11 to L15 read in step # 908 and
An image signal is formed from the signals of the pixels R11 to R15 read out in 5, and the distance to the object to be measured in the left direction is obtained based on the relative value of the image signal by the principle of triangulation. Then, a series of distance measuring operations is completed.

As described above, in the case of the multi-point distance measuring apparatus shown in FIG. 3, the area closer to the chip side surface among the areas of the sensor array shown in FIG. 4 is preferentially output and A / D converted. The A / D conversion can be completed before the charges generated by the incident light from the side surface of the chip leak into the signal storage unit.

Although it is assumed that the A / D conversion time is short here, the reading is performed in the order of R11 → R15 in step 905, but the reading may be performed in the order of R15 → R11.
In this case, it is possible to further reduce the influence of leakage charges.

(Third Embodiment) Next, a third embodiment will be described below.

The structure of the distance measuring device according to the third embodiment is the same as that shown in FIG. 3 and its explanation is omitted. The operation of the distance measuring device according to the third embodiment will be described with reference to the flowchart shown in FIG.

[# 1001] First, a photometric sensor (not shown) determines whether or not the brightness of the object to be measured is at a predetermined level or higher.

If the brightness of the object to be measured is less than the predetermined level, it is determined that there is almost no leakage of charges due to incident light from the side surface of the chip, and the next step 100
Move to 2.

On the other hand, when it is determined that the brightness of the object to be measured is equal to or higher than the predetermined level, it is determined that there is a charge leak due to the incident light from the side surface of the chip, and step 100
Go to 6.

Here, the brightness of the object to be measured is measured by a photometric sensor (not shown), but it is measured by the photoelectric conversion element 700, for example, by measuring the time taken to obtain a predetermined accumulated amount. The brightness of the distance object may be measured.

[# 1002] The signals in the first signal storage unit 705 and the second signal storage unit 706 are cleared by changing the RES pulse from L to H. Then, after a predetermined time, the RES pulse is changed from H to L, and ST1 and ST2, S
By setting all T3 pulses from H to L, signal accumulation of all pixels of the first and second sensor arrays is permitted, and the accumulation operation is started.

[# 1003] The PKMON signal level output from the peak detection unit 707 is A / D converted by an A / D conversion converter incorporated in the control unit (not shown), and the level is checked to determine the accumulated amount. Accumulation is continued until is at a predetermined level.

When the accumulated amount reaches an appropriate level, the process proceeds to the next step 1004.

[# 1004] ST1 and ST2, S
By setting all the T3 pulses to L → H, the accumulation operation in the first signal accumulating section and the second signal accumulating section is completed, and at the same time, the accumulated signal level of each pixel is held.

[# 1005] The signal read operation is started. First, when the CLK1 pulse is input as the read clock, the pixels L1 to L5 of the first sensor array 703 are input.
Signals are sequentially output as OUT signals. Similarly CL
K2 to CLK6 are input and the signals of all pixels are sequentially output.

At this time, the control unit (not shown) uses CLK1 to CL
The OUT output is A / D converted in synchronism with the K6 pulse and stored in a predetermined address of the RAM in the internal control unit to read the accumulated signal for all pixels.

After the signals of all the pixels are read out, an image signal is formed from the signals of the pixels L1 to L5 and the signals of the pixels R1 to R5, and based on the relative value of the image signals, the rightward direction is obtained by the principle of triangulation. Find the distance to the object to be measured. Similarly, the signals of the pixels L6 to L10 and the pixels R6 to R10 are
The distance from the signal to the distance measuring object in the central direction is obtained. Finally, the signals of the pixels L11 to L15 and the pixels R11 to
From the signal of R15, the distance to the object to be measured in the left direction is obtained, and a series of distance measuring operation is completed.

[# 1006] On the other hand, in step 1006, the signals in the first signal storage section 703 and the second signal storage section 704 are cleared by changing the RES pulse from L → H. Then, after a predetermined time, the RES pulse is changed from H → L and the ST1 pulse is changed from H → L to permit signal accumulation of the pixels L1 to L5 and pixels R1 to R5 of the first and second sensor arrays, and the accumulation operation is performed. Start.

[# 1007] The PKMON signal level output from the peak detection unit 707 is A / D converted by an A / D conversion converter incorporated in the control unit (not shown), and the level is checked to store the signal. Accumulation is continued until the amount reaches a predetermined level.

Then, when the accumulated amount reaches an appropriate level, the process proceeds to the next step 1008.

[# 1008] The ST1 pulse is changed from L to H, and the first signal storage section 705 and the second signal storage section 7 are set.
The accumulation operation of the pixels L1 to L5 and the pixels R1 to R5 in 06 is completed, and at the same time, the accumulation signal level of each pixel is held.

[# 1009] The signal reading operation is started. First, when the CLK1 pulse is input as the read clock, the pixels L1 to L5 of the first sensor array 703 are input.
Signals are sequentially output as OUT signals. Similarly CL
The K4 pulse is input to sequentially output the signals of the pixels R1 to R5.

At this time, an OUT output is A / D converted by a control unit (not shown) in synchronism with the CLK1 and CLK4 pulses and stored in a predetermined address of the RAM in the internal control unit to read the accumulated signal.

After reading the signal of a predetermined pixel, the pixel L
An image signal is formed from the signals of 1 to L5 and the signals of the pixels R1 to R5, and the distance to the object to be measured in the right direction is obtained based on the relative value of the image signal by the principle of triangulation. Move to step # 1010.

[# 1010] The signals in the first signal storage section 705 and the second signal storage section 706 are cleared by the RES pulse L → H. Then, after a predetermined time, the RES pulse is changed from H to L and the ST2 pulse is changed from H to L, so that the pixels L6 to L10 and the pixel R6 of the first and second sensor arrays are changed.
~ Allows signal accumulation of R10 and starts accumulation operation.

[# 1011] The PKMON signal level output from the peak detection unit 707 is A / D converted by an A / D conversion converter incorporated in the control unit (not shown), and the level is checked to store the signal. Accumulation is continued until the amount reaches a predetermined level.

When the accumulated amount reaches an appropriate level, the process proceeds to the next step 1012.

[# 1012] By changing the ST2 pulse from L to H, the pixels L6 to L10 and the pixels R6 to R10 in the first signal storage section 705 and the second signal storage section 706 are changed.
Then, the accumulation signal level of each pixel is held at the same time.

[# 1013] The signal read operation is started. When the CLK2 pulse is first input as the read clock, the pixels L6 to L1 of the first sensor array 703 are input.
The signal of 0 is sequentially output as the OUT signal. Similarly C
The LK5 pulse is input and the signals of the pixels R6 to R10 are sequentially output.

At this time, an OUT output is A / D converted by a control unit (not shown) in synchronism with the CLK2 and CLK5 pulses and stored in a predetermined address of the RAM in the internal control unit to read the accumulated signal.

After reading the signal of a predetermined pixel, the pixel L
An image signal is formed from the signals of 6 to L10 and the signals of the pixels R6 to R10, and based on the relative value of the image signal, the distance to the object to be measured in the center direction is obtained by the principle of triangulation.
Move to next step 1014.

[# 1014] The signals in the first signal storage section 705 and the second signal storage section 706 are cleared by the RES pulse L → H. Then, after a predetermined time, the RES pulse is changed from H to L and the ST3 pulse is changed from H to L, so that the pixels L11 to L15 and the pixel R of the first and second sensor arrays are changed.
The signal accumulation of 11 to R15 is permitted, and the accumulation operation is started.

[# 1015] The PKMON signal level output from the peak detection unit 707 is A / D converted by the A / D conversion converter incorporated in the control unit (not shown), and the level is checked to store the signal. Accumulation is continued until the amount reaches a predetermined level.

Then, when the accumulated amount reaches an appropriate level, the process proceeds to the next step 1016.

[# 1016] By changing the ST3 pulse from L to H, the pixels L11 to L15 and the pixels R11 to R15 in the first signal accumulating section 705 and the second signal accumulating section 706 are changed.
The accumulation operation of 15 is completed, and the accumulated signal level of each pixel is held at the same time.

[# 1017] The signal read operation is started. When the CLK3 pulse is first input as the read clock, the pixels L11 to L of the first sensor array 703 are input.
The 15 signals are sequentially output as OUT signals. Similarly, the CLK6 pulse is input to sequentially output the signals of the pixels R11 to R15.

At this time, an OUT output is A / D converted by a control unit (not shown) in synchronism with the CLK3 and CLK6 pulses and stored in a predetermined address of the RAM in the internal control unit to read the accumulated signal.

After reading the signal of a predetermined pixel, the pixel L
An image signal is formed from the signals of 11 to L15 and the signals of the pixels R11 to R15, and the distance to the object to be measured in the left direction is calculated based on the relative value of the image signal by the principle of triangulation. The distance measurement operation ends.

As described above, first, the brightness of the object to be measured is determined, and when the brightness is less than the predetermined level, the signals are collectively stored in all the pixels of the sensor array, and L1 to L1 are stored.
5, reading is performed in the order of R1 to R15. At this time, in the pixels in the vicinity of the pixel R15, the timing from the signal accumulation to the reading is considerably delayed, but the luminance of the object to be measured is low, so that it is hardly affected by the charge leakage.

Further, in the case of such a low luminance that charge leakage does not occur, the signal accumulation time becomes long, so that the accumulation operation is performed collectively for all areas rather than performing the accumulation operation for each area of the sensor array. Performing the operation shortens the time required for the entire distance measurement.

On the other hand, when the brightness of the object to be measured is higher than a predetermined level, signal accumulation operation, A / D conversion, and calculation are performed for each area of the sensor array, until the reading is completed after the accumulation is completed. By shortening the time of, the influence of electric charge leakage is eliminated. Also, at this time, the brightness of the distance measurement target is high, so the time required for the accumulation operation for each area is very short. Has almost no effect on

As described above, the signal storage operation and the A / D conversion operation timing are made different according to the brightness level of the object to be distance-measured, so that the distance can be measured in the shortest possible time while preventing the leakage of charges. You will be able to do it.

In the third embodiment described above, the sensor array is divided into three, and if the brightness of the object to be measured is at a predetermined level or higher, charge accumulation operation and A / D conversion are performed for each area.
The conversion is performed, and if it is less than the predetermined level, the accumulation operation and the A / D conversion are collectively performed in all areas, but the present invention is not limited to this. That is, the size of the area of the sensor array that performs the accumulation operation and the like at the same time may be determined according to the brightness level of the object to be measured. The higher the brightness level of the object to be measured, the more the charge accumulation operation and the A / It suffices to reduce the area in which D conversion is performed (that is, increase the number of divisions of the area). If the brightness level is low, it is not necessary to perform the accumulation operation collectively in all areas. The accumulation operation and A / D conversion may be performed in a region (that is, the number of divided regions is reduced).

[0101]

As described above, according to the present invention,
By preferentially outputting the pixel signal closer to the side surface of the chip, which is the light receiving means, and performing A / D conversion, it is possible to read out the signal before the charge generated by the incident light from the side surface of the chip leaks into the signal storage unit. This is possible, and erroneous distance measurement can be prevented even under high brightness such as outdoors.

Further, also in a multi-point distance measuring apparatus capable of measuring the distance to a plurality of distance measuring objects, the area closer to the chip side surface of the sensor array divided into a plurality of areas is given priority. By outputting and performing A / D conversion, it is possible to read the signal before the charge generated by the incident light from the side surface of the chip leaks into the signal accumulating portion. For example, erroneous distance measurement can be performed even under high brightness such as outdoors. Can be prevented.

Further, in a multi-point distance measuring device using a sensor array divided into a plurality of areas, when the brightness of the distance measuring object is low, accumulation and accumulation operations are simultaneously performed in all areas, for example at night. It is possible to shorten the time required for distance measurement during distance measurement. On the other hand, when the brightness of the object to be measured is high, the signal accumulation operation is performed for each area, so that the time from the completion of the accumulation operation to the A / D conversion of the signal output can be shortened. It is possible to read out the signal before the electric charge generated by the incident light from leaks into the signal storage unit, and it is possible to prevent erroneous distance measurement even under high brightness such as outdoors.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a distance measuring device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a timing chart and an output waveform when an output signal of the distance measuring device of FIG. 1 is captured.

FIG. 3 is a block diagram showing a configuration of a distance measuring device according to second and third embodiments of the present invention.

FIG. 4 is a diagram showing the correspondence between areas and pixels of a sensor array of the distance measuring device of FIG.

FIG. 5 is a flowchart for explaining a distance measuring operation of the distance measuring device according to the second embodiment of the present invention.

FIG. 6 is a flowchart for explaining a distance measuring operation of the distance measuring device according to the third embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a distance measuring device using a conventional photoelectric conversion device.

FIG. 8 is a timing chart showing a storage operation and a read operation of a conventional distance measuring device.

FIG. 9 is a diagram showing an example of a luminance distribution on a sensor array of a distance measuring device.

FIG. 10 is a diagram showing a timing chart and an output waveform when an output signal of a conventional distance measuring device is captured.

[Explanation of symbols]

201,701 First light receiving lens 202,702 second light receiving lens 203,703 First sensor array 204,704 Second sensor array 205, 705 First signal storage unit 206, 706 Second signal storage unit 207,707 Peak detector 208, 708 First signal output unit 209, 709 Second signal output unit

Continued front page    F-term (reference) 2F112 AC03 BA07 CA02 DA28 FA03                       FA21 FA45                 2H011 AA01 BA05 BB02 BB04 BB05                 2H051 AA01 BB07 CB20 CB25 CE02                       CE06 CE08 CE24 DA03 DA09                       DA22 DB01

Claims (7)

[Claims] 1. A photoelectric conversion element array provided on a semiconductor chip, in which a plurality of photoelectric conversion elements for receiving an image of an object to be measured are arranged, and a signal storage for accumulating charges converted by the photoelectric conversion element array. Means, a signal output means for outputting a signal corresponding to the amount of charge accumulated by the signal accumulating means, and a signal corresponding to the photoelectric conversion element near the chip end among the outputs from the signal outputting means. A distance measuring device comprising: an A / D converting means for A / D converting; and a distance calculating means for calculating a distance to the distance measuring object based on the signal converted by the A / D converting means. 2. The distance measuring device according to claim 1, wherein the photoelectric conversion element array is divided into a plurality of regions. 3. The distance measuring device according to claim 2, wherein the pixel signals of a region in the vicinity of a chip end of the plurality of regions are A / D converted. 4. A photoelectric conversion element array provided on a semiconductor chip for receiving an image of an object to be measured, a signal storage means for storing charges converted by the photoelectric conversion element array, and the signal storage means. A signal output means for outputting a signal according to the amount of accumulated charge, and an A / D for converting the output from the light receiving means into A / D conversion.
In a distance measuring device including a converting means and a distance calculating means for calculating distances to the plurality of distance measuring objects based on the A / D-converted signals, the luminance of the distance measuring objects has a predetermined level. If the size of the region of the photoelectric conversion element array that performs A / D conversion after simultaneously accumulating charges is different according to the determination result of the brightness determination unit, the brightness determination unit determines whether or not the above is satisfied. Distance measuring device characterized by being able to 5. The photoelectric conversion element array is divided into a plurality of areas when the brightness of the object to be measured is determined to be equal to or higher than a predetermined level by the brightness determining means, and the charge of each area is divided into a plurality of areas. After the accumulation, A / D conversion is performed, and when it is determined that the brightness of the object to be measured is not equal to or higher than a predetermined level, the charges are accumulated simultaneously in the entire area of the photoelectric conversion element array. The distance measuring device according to claim 4, wherein A / D conversion is performed. 6. The photoelectric conversion element array is divided into a plurality of regions when the brightness of the object to be measured is determined to be equal to or higher than a predetermined level by the brightness determination means, and the charge of each region is divided into a plurality of regions. When accumulation and A / D conversion are performed and it is determined that the brightness of the object to be measured is not equal to or higher than a predetermined level, the photoelectric conversion element array is divided into regions smaller than the plurality of regions, and this region is divided into the regions. Charge accumulation and A
The distance measuring device according to claim 4, wherein the D / D conversion is performed. 7. A camera comprising the distance measuring device according to claim 1. Description: