JPS59183321A - Storage type photoelectric convertor - Google Patents

Abstract

PURPOSE:To obtain a charge level standardized for controlling the focusing for a short time by providing a charge storage section operating during the projection and a charge storage section operating during a fixed period in the non-projection time corresponding to two photoelectric conversion sections to obtain a control information after the sum of charge levels of both the storage sections is detected. CONSTITUTION:With the emission of light from a light emitting element, reflected lights from an object form an image on a photoelectric conversion element. The conversion element is provided with photoelectric conversion sections AS and BS and the sum of reflected lights and ambient lights by projection is stored into corresponding charge storage sections AL and BL while ambient lights during a fixed period in the non-projection done into charge storage sections AD and BD. Information corresponding to the sum of the charge levels stored in the storage sections AL and BL is detected in a non- destructive manner through a floating gate FG1 while information corresponding to the sum of the charge levels stored in the storage sections AD and BD done so through a floating gate FG2 and a signal VA+B is outputted through a differential amplification circuit DA4. When the signal VA+B exceeds a reference voltage determined by resistance, the detection of distance with a high S/N ratio can be performed by a signal VA-B.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a storage type photoelectric conversion device, and more particularly, to a storage type photoelectric conversion device, which emits light onto a subject, receives reflected light from the subject with a light receiver, and uses a signal from the light receiver to transmit light to the subject. The present invention relates to a storage type photoelectric conversion device that is effective in distance detection. Conventionally, non-storage type photoelectric conversion elements such as silicon photodiodes are often used as photoelectric conversion elements for distance detection, but since the output signals generated by these photoelectric conversion elements are very small, circuit noise is generated during amplification. 87. The detection distance was also short. SUMMARY OF THE INVENTION An object of the present invention is to provide a storage type photoelectric conversion device which has a high transmission range and has a control means for performing a predetermined operation based on a signal obtained during distance detection.

The main features of the storage type photoelectric conversion device for achieving the object of the present invention are: a light source for projecting light onto a subject; a photoelectric conversion means having an incident conversion section for receiving reflected light from the subject; first and second charge storage sections that accumulate charges generated in the first and second photoelectric conversion sections, respectively, while the light source is emitting light; 1. It has a third and a fourth charge accumulation section that respectively accumulate charges generated in the second photoelectric conversion section, and the sum S1 of the amount of charge accumulated in the first and second charge accumulation sections.
a first gate means such as a floating gate that non-destructively detects information corresponding to S2; The present invention has two gate means, and includes a control means for performing the next operation after detecting the output of the first gate means and the output of the second gate means. Note that the light source may be provided outside the storage type photoelectric conversion device. The control means detects each charge accumulated in the first to fourth charge storage sections after the difference between the output of the first gate means and the output of the second gate means reaches a certain reference value. I try to do that.

Further, a warning display means is provided to display a warning when it is determined that the difference between the output from the first gate means and the output from the second gate means does not reach a reference value after a certain period of time has elapsed. ing.

Further, in order to ensure proper operation of the photoelectric conversion section, a warning is displayed when it is determined that the output of the first gate means or the second gate means exceeds a certain level.

Next, one embodiment of the present invention will be described using the respective figures.

FIGS. 1(a), (b), and (c) are explanatory diagrams of photoelectric conversion means used in the storage type photoelectric conversion device according to the present invention.

Figure 1 (a) shows the amount of charge A, B generated in the two photoelectric conversion units A, B, when the light is emitted from the light source, and the amount of charge generated in the surrounding area when the light emitted is stopped. This is a conceptual representation of the amount of charge AQ and Bo generated by light. , B'+B, from each photoelectric conversion unit AI, Bl to the eleventh second charge storage unit A2, B
When the light is not emitted, the photoelectric conversion parts A and s 13
Charge A generated on +. , Bo are the third and fourth charge storage parts A
3 and B, respectively.

By taking the difference between these accumulated charges in a differential circuit, only the charge amounts A and B of the reflected light components due to the projection of light are detected, as shown in Fig. 1(b), and as a result, as shown in Fig. 1. When the charge amounts A and B are A=H as shown in (c), for example, the lens system of the distance detection system determines that it is the in-focus position, and when A>B, the previous bin state, A<
When it is H, it is determined that it is in the bin state. Further, at this time, it is preferable to maintain a constant value of A+B for the amount of charge, since the slope of A-B near the in-focus position will be approximately constant, and the focusing accuracy can be maintained constant.

FIG. 2 is an explanatory diagram of one embodiment of the storage type photoelectric conversion means used in the present invention, in which AS and BS are first and second photoelectric conversion units, and AL and BL are at the time of light emission and when light is emitted. The first °Kf:r2-4, which accumulates the sum of reflected light and ambient light, is the photoelectric converter AS1BS when φICG is at a high level.
An integral clearing game to clear the resulting charge),
SHI and SH2 are charge transfer gates. When φSH is at a high level, the generated charges are accumulated in the charge storage units AL and BL (photoelectric conversion unit A31BS), and when φSH is at a low level, SH2 is transferred through the inverter INI. At high level, the charges generated from the photoelectric conversion sections As and BS are transferred to the charge storage section AD.

Store on BD. TGI to TG4 are charge transfer gates, and when φTG is at a high level, the charges stored in the charge storage section are transferred to the charge voltage conversion sections BCI to BC4, and signal reading is performed. BCI has the signal A+Ao in FIG. 1(a), BO2 has the signal B+B, and BO2 has the A signal. signal, B for BO4.

The signal (A+
Ao ) (Ao) -A, via the differential amplifier circuit DA2 (B + B, )) - (Bo) ='B, the signal vA-it of A-B is output via the differential amplifier circuit DA3. Ru. Also, the charges accumulated in AL and BL and AD and BD are (A+Ao) + (B 1 B.) and A. +B0 is non-destructively read out via FGI and FG2, and is read out via differential amplifier circuit DA4 (A+A
o ) + (B + B.) - (AO + B, l) = A + B
A signal VA+B is output. It is an object of the present invention to read out the signal when the output of A+8 reaches a reference value. After reading and detecting the signal, φR5 is set to high level to reset unnecessary signals.

FIG. 3 shows an embodiment of an electric circuit for driving the photoelectric conversion means shown in FIG. 2 and realizing the present invention, and FIG. 4 is a timing chart of the main parts of FIG. When the power switch SW is turned on at time t0, the output of the AND gate ANO is inverted to a high level for a short time determined by the capacitor C7 and the resistor R2o in synchronization with the rising edge of the OSC, so the one-shot circuit ONI generates a one-shot pulse and passes it through OR gates OR3, OR4, OR5 at time t.
0 time t, when unnecessary charges in the storage type photoelectric conversion element are cleared between 0 and t.

The RST 71J block flop RFI is reset in synchronization with the rising pulse of the OSC. Also, since the transistor Tri is turned on by the 08CQ high level signal, the light emitting element LD emits light with the current regulated by the resistor R1.
The light is projected onto the object OB via the light projecting lens LNI, and the reflected light forms an image on the photoelectric conversion element via the light receiving lens LN2.

When a reflected light image is formed at the center of the photoelectric conversion units A1 and B1, the outputs from the photoelectric conversion units A, , and B become equal, which is the in-focus position. When the output of one-shot ON1 is reversed to low level at time t2, when OSC is high level, the reflected light signal at the time of light emission is transferred to the charge storage parts AL and BL.
When OSC is at a low level, the non-emission signal is from charge storage section A.
The data is stored alternately in D and BD. At time t, when the signal of VA+B exceeds the reference voltage determined by resistors R2 and Rs, the output of comparator CPI is inverted to the high level side, so at time t.
At step 4, the R8T flip-flop RF1 is set in synchronization with the rising edge of the OSC pulse, and the one-shot ON2 generates a one-shot pulse to set φICG to a high level and complete the storage of image information in the storage type photo-electric conversion element. . At the same time, φ is passed through AND gate ANI and OR gate OR5.
TG is set to high level and stored information is read out, and the sample and hold circuit SHD is set to VA- between ~t.
Sample and hold the information of B. Since φR5 is set to high level through AND gate AN2, inverter IN2, and OR gate OR3 between times t and ~t, unnecessary charges stored in the charge voltage converter are reset, and from time t0 Accumulation of new image information begins. Note that the RFI is configured to be reset by the output of AN2 at time t. Time t6-tl.

At time t. -t, image information is detected in the same way as during time t, and new image information is sampled and held between time t and time t. The information sampled and held in the SHD is used to drive the photographic lens to the in-focus position via the control circuit CKT. Also, resistors R7 to R9, capacitor C11
A timer circuit consisting of a transistor Tr3s and a comparator CP3 turns on a transistor Tr4 when the above sequence is not repeated within a certain period of time, that is, when the surroundings are dark and the subject is far away and the reflected light is weak.
The light emitting element LE2 is configured to emit light to warn the photographer. Furthermore, if the surroundings are bright, the subject is far away, and the reflected light is weak, v5 will exceed the voltage near saturation determined by resistors R4 and R5 before the above sequence is repeated, so comparator CP2 will shift to the high level side. Since the light is reversed and the transistor Tr2 is turned on, the light emitting element LEI emits light to warn the photographer.

As described above, when the storage type photoelectric conversion device invented in the United States is used for distance detection, for example, a signal of charge A + H can be obtained in real time, so a signal of the standardized charge A - H can be obtained in a short period of time. Therefore, it has a remarkable effect on detecting the distance to the subject.

[Brief explanation of drawings]

Figure 1 (a) s (b) % (c) is an explanation of the storage type photoelectric conversion means used in the storage type photoelectric conversion device according to the present invention. Figure 2 is an illustration of an embodiment of the photoelectric conversion means used in the present invention. FIG. 3 is an explanatory diagram of one embodiment of an electric circuit for driving the photoelectric conversion means used in the present invention, and FIG. 4 is a timing chart of the main parts of FIG. 3. In the figure, A, , B are photoelectric conversion parts, A2 % A3 , B
2, B3 is a charge storage section, A, B, Ao, Bo
indicates the amount of charge. Patent applicant Canon Co., Ltd. ~ Slant 5 Associate! Written amendment (spontaneous) Kazuo Wakasugi, Commissioner of the Japan Patent Office, March 1987, 1982.1 Indication of the case, 1982 Patent Application No. 57203.2 Name of the invention, Accumulation certificate source power converter device3. Relationship Patent Applicant Location: 3-3C1-2 Shimomaruko, Ota-ku, Tokyo Name (+00) Canon Co., Ltd. Representative: Ryu Kaku Sanbu 4 Agent Address: Leap 146, Canon Co., Ltd., 3-30”-2 Shimomaruko, Ota-ku, Tokyo (+00) (Telephone 758-2111) 5 Subjects of amendment (1) Specification (2) Drawings 6, Contents of amendment (1) (a) Specification declaration, page 4, line 17 to line 19, ``In addition, the light source ...It's best to leave it behind.'' is deleted. (2) Figure 5 of the drawings shall be amended as shown in the attached sheet.

Claims (4)

[Claims] (1) A light source for projecting light onto the subject and a first light source for receiving the reflected light from the subject, whose amount of stain varies depending on the amount of incident light.
and a second photoelectric conversion unit, and first and second charge storage units that accumulate charges generated in the first and second photoelectric conversion units, respectively, while the light source emits light. a third and a fourth charge storage section that accumulate charges generated in the first and second photoelectric conversion sections, respectively, for a certain period of time when the light source does not emit light; a first gate means such as a floating gate for non-destructively detecting information corresponding to the sum S1 of the charges accumulated in the charge accumulation section; and a sum S2 of the charges accumulated in the third and fourth charge accumulation sections; and a second gate means for non-destructively detecting information corresponding to the second gate means, and a control means for causing the next operation to be performed after detecting the output of the first gate means and the output of the second gate means. A storage type photoelectric conversion device Ω characterized by (2) The control means controls each charge accumulated in the first to fourth charge storage sections after the difference between the output of the first gate means and the output of the second gate means reaches a certain reference value. 2. The storage type photoelectric conversion device according to claim 1, wherein the storage type photoelectric conversion device is configured to detect. (3) The control means displays a warning when the control means determines that the difference between the output from the first gate means and the output from the second gate means does not reach a reference value after a certain period of time has elapsed. 2. The storage type photoelectric conversion device according to claim 1, further comprising warning display means. (4) The control means has a warning display means for displaying a warning when it is determined that the output of the first gate means exceeds a certain level. Storage type photoelectric conversion device.