JPH05173058A - Range-finding and photometric device - Google Patents

Abstract

PURPOSE:To provide a range-finding and photometric device in which entire measuring time is shortened on plural areas. CONSTITUTION:This device is constituted of a light projecting circuit part 21 projecting a light pulse toward an object, a photoelectric current detecting circuit part 22 constituted of plural photoelectric current detecting circuits 22a-22f which receive reflected light from a range-finding object and detect and amplify a signal pulse photoelectric current component, an arithmetic outputting circuit part 23 finding the distance information of the object from a photoelectric current obtained from the photoelectric current detecting circuits 22a-22f, a counting circuit part 24 A/D converting the output of the circuit part 23, a controlling circuit part 25 transmitting a controlling signal to each circuit part, and a circuit 26 logarithmically compressing the photoelectric current of the photometric device; and photometric action is executed by means of the photometric device at the time of non-projecting light between light projection repeatedly performed for range-finding and photometry.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring and photometric device for measuring and measuring light at a plurality of locations within a predetermined area.

[0002]

2. Description of the Related Art Generally, an active type has been known as a distance measuring device for an image pickup device such as a camera.

This distance measuring device measures the distance to a subject by projecting light from a camera toward the subject and receiving reflected light reflected from the subject. In such a distance measuring device, so-called multi-beam autofocus (multi-beam AF) is realized, in which a plurality of light is projected toward a plurality of subjects.

On the other hand, a camera having a distance measuring and photometric device which measures the brightness of each of a plurality of areas of the object field, determines whether or not there is backlight, and controls the exposure based on an appropriate reference Proposed.

When performing distance measurement and photometry in a plurality of areas in this way with the camera as described above, in each of the distance measurement process and photometry process consisting of a plurality of processes, each process is processed in parallel or simultaneously processed in a plurality of processes. According to the time series without doing
If processing is performed step by step, it takes a considerable amount of time to complete distance measurement and photometry for the entire area, and it may not be possible to take the image at the moment desired by the user.

In order to solve such a problem, as described in Japanese Patent Application Laid-Open No. 2-8708, active distance measurement and photometry for a plurality of areas of a field are performed from one area. Disclosed is a method for speeding up camera operation by utilizing the charge waiting time in the light projecting means until distance measurement in the next area and taking in the photometric output of one area into the data conversion processing means. ing.

[0007]

However, in the above-mentioned method, since the distance measurement and the photometry operation are repeatedly performed in a time series, it is not possible to expect a drastic reduction in the diagram.
The overall time required for photometry is not much different from the conventional one.

Further, this system is of a type that does not perform charging for projecting light by the light projecting means (no charging waiting time), or even if there is a charging waiting time, at least one It cannot be used when the distance measurement (photometry) of the area cannot be performed.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a distance measuring and photometric device in which the total measuring time for a plurality of regions is shortened.

[0010]

In order to achieve the above object, the present invention provides a light projecting means for repeatedly projecting a light beam toward an object and a light beam reflected from the object to receive the object distance. Distance detecting means for outputting a signal according to, and photometric means for detecting the brightness of the subject,
It is possible to provide a distance-measuring and light-measuring device including a control unit that controls the light-metering operation repeatedly performed by the light-projecting unit so as to be performed during non-light-projection between the light-projections.

[0011]

The distance measuring and photometric device having the above-described structure incorporates the processing of the calculation output of the distance measuring and photometry in the waiting time between the light projections in the sequence of the distance measuring and photometry operations. In parallel with the detection of the distance measurement and the photometry, the distance measurement and the photometry are executed during the non-light emission between the light emission operations.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a schematic construction of a distance measuring and photometric device as a first embodiment according to the present invention.

This distance measuring and photometric device includes six silicon photo (SP) diodes 1a to 1f as light receiving elements.
Is provided. These SP diodes are (1a, 1b), (1c, 1d), (1e, 1f),
A pair (hereinafter referred to as a light receiving element pair) is formed. A red light emitting diode (hereinafter, I
One of the light emitting elements 2a, 2b, and 2c composed of RED) is made to correspond to each other, and three sets are configured to perform distance measurement at predetermined three positions within the imaging screen.

That is, the light emitted from the light emitting elements 2a, 2b, 2c is projected onto the subject 4 via the light projecting lens 3. The reflected light reflected by the subject 4 is received by the light receiving element pair 1 via the distance measuring light receiving lens 5, converted into an electric signal and output to the distance measuring and photometry circuit means 6.

Further, the photometric element 7 has a light-receiving surface divided into three parts, that is, configured so as to perform photometry by dividing the image pickup screen into three parts, and the reflected light from the subject 4 is received via the photometric light-receiving lens. Then, it is converted into an electric signal and outputted to the distance measuring and photometric circuit means 6.

Next, FIG. 2 shows an overall block diagram of the electric circuit of the distance measuring and photometry device of the first embodiment, and FIG. 3 shows the timing of signals supplied from the control circuit section 25 shown in FIG. Charts are shown, and the configuration of the distance measuring device and the distance measuring operation will be described with reference to these.

As shown in FIG. 2, a light projecting circuit section 21 for projecting an optical pulse to the object to be measured, and a plurality of units for receiving the reflected light from the object to be detected and detecting and amplifying the signal pulse photocurrent component. A photocurrent detection circuit unit 22 including the photocurrent detection circuit, a calculation output circuit unit 23 for obtaining the distance information of the object from the photocurrent obtained from the photocurrent detection circuit, and an output of the calculation output circuit unit 23 A count circuit section 24 for D / D conversion,
The control circuit section 25 sends a control signal to each circuit section. A circuit 26 for logarithmically compressing the photocurrent is provided as a photometric device. The resistor R and the capacitor C are low-pass filters for removing the influence of AC background light such as fluorescent light.

Next, FIG. 3 shows the control circuit section 25 shown in FIG.
A timing chart of a signal supplied from the above is shown, and the distance measuring operation will be described with reference to this.

In the start portion of section A shown in FIG. 3, the level of the control signal S1 output from the control circuit section 25 is "L", the level of the control signal S2 is "H", and the level of the control signal S3 is "H". H ". At this time, the distance measuring device having the configuration of the light receiving element pair 1 and the light emitting element 2 is selected.

4A to 4C, 5A and 5B
Shows a specific circuit diagram of each unit shown in FIG.
This will be described in detail with reference to the overall configuration diagram of FIG.

First, the red light emitting diode (IRED) 68 of the light projecting circuit section 21 shown in FIG. 4A is driven by a constant current drive circuit composed of a transistor 67, resistors 66 and 69 and an operational amplifier 65. To be done. The base of the transistor 70 for controlling the on / off of the constant current drive circuit is connected to the terminal T1 of the control circuit 25 via the resistor 71, and the infrared light projected from the red light emitting diode 68 in a pulse waveform. ON / OFF control of
This is performed by the output signal of the terminal T1 of the control circuit unit 25.

The photocurrent detection circuit section 22 shown in FIG. 4B includes a preamplifier circuit section composed of an operational amplifier 3 and a transistor 2, a background light removal circuit section composed of an operational amplifier 5, a transistor 4 and peripheral circuits thereof. Transistor 8,
And a current mirror circuit composed of 9, 8A and 9B. The signal pulsed photocurrent I1 obtained from the anode of the SP diode 1a is supplied to the operational amplifier 3 forming the preamplifier circuit. The operational amplifier 3 has its output end connected to the emitter of the transistor 2, its inverting input end to its base, and its non-inversion input end to the reference power supply Vref so that feedback can be applied by the transistor 2. The base input resistance of No. 2 is equivalently lowered to several tens of KΩ.

In the operational amplifier 5 constituting the background light removing circuit section, the "H" level of the output signal of the terminal T1 of the control circuit section 25 of FIG. 2 is applied to the base of the transistor 6 via the resistor 73 when the light is not projected. By being given, it becomes active when turned on, and the capacitor 7 connected to its output end
In addition to accumulating electric charges according to the brightness of the background light, the feedback loop constituted by the capacitor 7 and the transistor 4 causes the photocurrent component due to the background light of the SP diode 1a and the bias current component of the operational amplifier 3 to be generated. Is discharged to the ground line as the collector current of the transistor 4.

As a result, the collector current of the transistor 2 has a value substantially corresponding to the pulse signal photocurrent regardless of the size of the background light. At the time of light projection, the transistor 6 is turned off, so the operational amplifier 5 becomes non-active. However, since the transistor 4 continues to discharge the photocurrent due to the background light to the ground line by the charge accumulated in the capacitor 7, the pulsed light component obtained by removing the photocurrent due to the background light from the photocurrent obtained from the anode of the SP diode 1a. Is multiplied by βn by the transistor 2, folded by the current mirror circuits 8 and 9, and injected as a signal pulse photocurrent βnI1 into the compression diode 46 of the operation output circuit unit 23.

The photocurrent I2 obtained from the anode of the other SP diode 1b is also processed by the photocurrent detection circuit section 22b which operates in the same manner as the circuit section 22 to produce the signal pulse photocurrent βnI2. , And the current mirror circuits 8A and 9A fold it back.

The arithmetic circuit section 23 of FIG. 5A is composed of transistors 41, 42, 44, 45 and compression diodes 46, 4.
7, constant current source 43, and buffer circuits BUF1 and BU
The logarithmic decompression circuit for obtaining the distance measurement calculation output is composed of F2. The bases of the transistors 41 and 42 forming the differential amplifier are respectively the compression diode 46,
47 is connected to each anode via buffer amplifiers BUF1 and BUF2, and each emitter is connected to the constant current source 43 via current mirror circuits 48 and 49. The collector of the transistor 42 is connected to the bases of the transistors 44 and 45 forming the current mirror circuit and the collector of the transistor 44.

The currents I1b and I2b flowing through the diodes 46 and 47, respectively, are the photocurrent detection circuit section 22.
The circuit is connected so that the signal pulse photocurrent output from the device flows.

Therefore, in the operation output circuit section 23, the above-mentioned current I1b becomes the signal pulse photocurrent βnI1 from the photocurrent detection circuit section 22 and the current I2b becomes the signal pulse photocurrent βnI2 from the photocurrent detection circuit section 22b. From

[0030]

[Equation 1] Is.

Therefore, assuming that the collector current Ic of the transistor 42 is the constant current Ie of the constant current 43,

[0032]

[Equation 2] Becomes Therefore, the collector current Iout of the transistor 45, which is the output of the calculation output circuit unit 23, is expressed by the equation (1),
Substituting into equation (2),

[0033]

[Equation 3] Becomes

The collector current Iout shows a distance measuring characteristic diagram showing a distance measuring range from infinity to the closest distance according to the reciprocal of the object distance a as shown in FIG. Therefore, the distance to the subject can be obtained from this.

The counting circuit section 24 has a collector current Iout of the transistor 45 of the operation output circuit section 23.
Is calculated and digitally measured by a counter mechanism (not shown) built in the control circuit section 25.

Output current Iou of the arithmetic output circuit section 23
t is calculated as follows.

Each time the light is projected, the transistor 50 is turned off, the output current of the operation output circuit section flows to the capacitor 52, and the electric charge is accumulated. Operational amplifier 53
Is for resetting the capacitor 52, and the base of the transistor 54 for controlling the capacitor is a resistor 76.
Is connected to the terminal T3 of the control circuit section 25 via. Therefore, depending on the level of the output signal of this terminal T3,
The transistor 54 is turned on, the potential of the capacitor 52 is set to the reference voltage Vref, and it is turned off immediately before the start of light projection to disable the operational amplifier 53.

After that, the potential of the capacitor 52 increases due to the injection current into the capacitor 52.

When the light emission of a predetermined number of times is completed, the level of the output signal of the terminal T4 changes from "H" to "L" as shown in the section A of the timing chart of FIG. Through, the transistor 63 is turned off,
The transistor 55 discharges the capacitor 52. At the same time, the counter built in the control circuit unit 25 operates and continues counting until the output of the comparator 62 becomes “H”. The signal level of the comparator 62 changes from “L” to “H” when the voltage across the capacitor 52 becomes lower than the reference voltage Vref. The discharge speed of the capacitor 52 is determined by a current mirror circuit including a constant current source 61 and transistors 55 and 56 connected in series with the constant current source 61. In this way, the output corresponding to the subject distance can be obtained as the count value of the counter in the control circuit 25.

Similarly, in the section B of FIG. 3, the level of the control signal S1 output from the control circuit section 25 is "H", the level of the control signal S2 is "H", and the control signal S3.
When the level of L is "L", the light receiving element pair 1c, 1
Distance measurement is performed by the configuration of d and the light emitting element 2b.

Further, in section C of FIG. 3, the level of the control signal S1 output from the control circuit section 25 is "H", the level of the control signal S2 is "H", and the control signal S3.
When the level of L is "L", the light receiving element pair 1e, 1
Distance measurement is performed by the configuration of f and the light emitting element 2c.

With these distance measurements, it is possible to perform distance measurement at three points within the image pickup screen.

Next, photometry is performed by the photometry circuit section 26 shown in FIG. 5 (b). The photometric circuit section 26 includes a light receiving element 2A, a logarithmic compression circuit, and an output switching buffer.

The output of the logarithmic compression circuit is the light receiving element 2A.
The photocurrent output Ip of

[0045]

[Equation 4] Can be expressed as

The voltage value is a photometric output in which the photocurrent output Ip is increased by 18 mV (at 300 ° K) each time it doubles.

This photometric output is put into A / D conversion, and A / D
By converting, the subject brightness can be measured. The effect of AC background light from a fluorescent lamp or the like is removed by the low-pass filter of the resistor R and the capacitor C shown in FIG.

When the level of the control signal S4 output from the control circuit section 25 is "H", the level of the control signal S5 is "L", and the level of the control signal S6 is "L", the light receiving element 2A. Will enable photometry.

Similarly, the level of the control signal S4 is "L", the level of the control signal S5 is "H", and the control signal S6.
When the level of "1" becomes "L", photometry becomes possible with the light receiving element 2B. Further, the level of the control signal S4 is "L",
When the level of the control signal S5 is "L" and the level of the control signal S6 is "H", photometry can be performed by the light receiving element 2C.

As described above, the control signals S4, S5,
By selecting S6, it is possible to perform photometry on three areas within the imaging angle of view.

Next, the operation of the first embodiment will be described.

The distance measuring / photometering operation as shown in the time chart of FIG. 3 is generated by the flow chart shown in FIG.

First, the level of the control signal S1 output from the control circuit section 25 is "L", the level of the control signal S2 is "H", the level of the control signal S3 is "H", and the distance measuring light-receiving element pair 1a. , 1b and the light emitting element 2a are enabled.
Similarly, the level of the control signal S4 is "H", the level of the control signal S5 is "L", the level of the control signal S6 is "L", and the photometric output by the photometric light receiving element 2A is selected. This output is stabilized by passing it through a low pass filter.

Further, the output signal from the terminal T1 prohibits the light projecting operation and the distance measurement calculation output synchronized with it at the "L" level, and the output signal from the terminal T3 is at the "H" level and the integrating capacitor 52 is output. Reset. Further, when the output signal from the terminal T4 is at the "H" level, inverse integration is prohibited (step # 1).

Next, the operation of step # 1 is executed for a predetermined time of 6 msec preset in the timer 1, and the stabilization of the set state is waited (step # 2). Then, the output signal from the terminal T3 changes from the "H" level to the "L" level, the reset of the integration capacitor 52 is released, and the integration of the distance measurement calculation output is enabled (step # 3).

Next, with respect to the light emitted from the light emitting element,
In synchronization, the integration calculation output is integrated into the integration capacitor 52,
Here, analog conversion A / D of the photometric output is performed in parallel (step # 4). After that, inverse integration is performed to obtain the distance measurement calculation output as a count value (step # 5).

Further, the level of the control signal S1 output from the control circuit section 25 becomes "H", the level of the control signal S2 becomes "L", the level of the control signal S3 becomes "H", and the distance measuring light receiving element pair The light emitting elements 2b and 1c and 1d are enabled (step # 6). The level of the control signal S4 is "L",
When the level of the control signal S5 is "H" and the level of the control signal S6 is "L", the photometric output by the photometric light receiving element 2B is selected (step # 7).

Then, the operations of steps # 6 and # 7 are carried out by the timer 2 set to the predetermined time of 6 msec, and the stabilization of the set state is waited (step # 8).

Next, the output signal from the terminal T3 of the control circuit section 25 changes from the "H" level to the "L" level, the reset of the integration capacitor 52 is released, and the integration of the distance measurement output is enabled (step # 9). Next, in synchronization with the light projected from the light emitting element, the distance measurement calculation output is integrated in the integration capacitor 52, and the analog conversion A /
D is performed in parallel (step # 10). afterwards,
Inverse integration is performed to obtain the distance measurement calculation output as a count value (step # 11).

Next, the level of the control signal S1 output from the control circuit section 25 becomes "H", the level of the control signal S2 becomes "H", the level of the control signal S3 becomes "L", and the light receiving element for distance measurement is obtained. The pair 1e and 1f and the light emitting element 2c are enabled (step # 12). The level of the control signal S4 is "L", the level of the control signal S5 is "L", the control signal S6
Is "H", the photometric output by the photometric light receiving element 2C is selected (step # 13). And the predetermined time 6
The operation of steps # 12 and # 13 is performed by the timer 2 set to msec, and the stabilization of the setting state is waited (step # 14).

Next, the output signal from the terminal T3 of the control circuit section 25 changes from the "H" level to the "L" level, the reset of the integration capacitor 52 is released, and the integration of the distance measurement output is enabled (step # 15). Next, the light is emitted from the light emitting element, and the distance measurement calculation output is integrated with the integration capacitor 52 in synchronization with the light, and the light conversion output is converted into an analog conversion A / D.
Are carried out in parallel (step # 16). Then, inverse integration is performed to obtain the distance measurement calculation output as a count value (step # 17).

Next, the integration operation of light projection will be described with reference to the flowchart of FIG.

First, the variable K indicating the number of times of light projection is set to "0" (step # 21). Terminal T of the control circuit 25
The signal from 1 is projected as "L" level. At that time, the distance measurement calculation output is integrated in synchronization with the light projection (step # 22). Then, the projection time of the "L" level signal from the terminal T1 is set by the timer 3 set to the predetermined time of 100 .mu.sec (step # 23).

Next, the "L" level signal from the terminal T1 is set to "H" level to turn off the light emission and wait for the red light emitting diode (IRED) of the light emitting element to be cooled (step # 24). Then, it is determined whether or not the variable K = 2 (step # 25). If the variable K = 2 in this determination (YES), the integrated distance measurement calculation output is converted into an analog (A
/ D) convert and read the photometric output (step # 2)
6). After that, after waiting for a predetermined time set by the timer 7, the process proceeds to the next step # 29 (step # 2
7). However, the variable K is "2" in the determination in step # 25.
Otherwise (NO), the "H" level output signal is output from the terminal T1 according to the timer 4 set to 2 msec in advance (step # 28).

Then, "1" is added to the variable K and incremented (step # 29). After that, light measurement is repeatedly performed until the number of times of light emission reaches three times, and when K = 4 or more, the light emission operation ends (step # 3).
0).

Next, the inverse integration operation will be described with reference to the flowchart of FIG.

First, the variable C is set to "0" (step # 31). The signal from the terminal T4 of the control circuit 25 is set to the "L" level to start inverse integration (step # 3).
2).

Next, it is judged whether or not the signal from the terminal T5 is at the "H" level (step # 33). If the signal is not at the "H" level by this judgment (NO), "1" is added to the variable C. To increment (step # 34). However, if the signal is "H" level (YES), the signal from the terminal T3 is set to "H" level to reset the integration capacitor 52, and the signal from the terminal T4 is set to "H" level to perform the inverse integration. It is prohibited (step # 35).

Next, it is determined whether the control signal S1 is at "L" level (step # 36), and if it is at "L" level (YE
S), the value of the variable C is stored in the memory M1 and the operation ends (step # 37). However, if it is not at "L" level (NO), it is determined whether the control signal S2 is at "L" level (step # 38). In this judgment, the control signal S2 is "L".
If it is the level (YES), the value of the variable C is stored in the memory M2 and the operation is finished (step # 39). However, if it is not at the “L” level (NO), the variable C is stored in the memory M3.
Value is stored and the operation ends (step # 40).

Next, the A / D conversion operation of the integrated distance measurement calculation output will be described with reference to the flowchart of FIG.

First, the input distance measurement calculation output is converted into analog (A / D) by a successive comparison in a conversion time of about 2 msec (step # 41).

Next, it is determined whether the control signal S1 is at "L" level (step # 42), and if it is at "L" level (YE
S), A / D converted distance measurement calculation output is stored in the memory M4 (step # 43). However, if it is not the "L" level (NO), it is determined whether or not the control signal S2 is the "L" level (step # 44). In this determination, if the control signal S2 is at the “L” level (YES), the A / D is stored in the memory M5.
The converted distance measurement calculation output is stored (step # 4).
5). However, if it is not the "L" level (NO), the distance measurement calculation output is stored in the memory M6 (step # 4).
6).

By such distance measuring and photometering operations shown in the flow charts of FIGS. 6 to 8, the three distance measuring values and the three light measuring values are stored in the memories M1 to M6, and the lens extension and , Exposure control is executed.

Next, a second embodiment according to the present invention will be described.

The structure of the second embodiment is the same as the structure of the first embodiment described above, and the same reference numerals are used for the structure and the description thereof is omitted. The timing chart of FIG. 10 shows the operation of the second embodiment, and FIG. 11 shows a flowchart for carrying out the timing chart of FIG.

In the first embodiment, the lens extension and the exposure control are executed for one set of the light receiving element pair and the light emitting element based on the distance measurement / photometry value obtained by one A / D conversion. On the other hand, as shown in the timing chart of FIG. 10, in the second embodiment, the distance measurement / photometry value measured each time the light is projected is A / D for one set of the light receiving element pair and the light emitting element.
Convert and calculate the average value. The lens extension and the exposure control are executed based on the average value, and the accuracy is improved.

This distance measuring / photometering operation will be described with reference to the flowchart of FIG.

First, the level of the control signal S1 is "L", the level of the control signal S2 is "H", the level of the control signal S3 is "H", and the pair of distance measuring light receiving elements 1a and 1b and the light emitting element 2a.
Enable. Similarly, the level of the control signal S4 is “H”, the level of the control signal S5 is “L”, the control signal S6.
Is "L", the photometric output by the photometric light receiving element 2A is selected. Also, the output signal from the terminal T1 is "L".
Set to the level to inhibit the light emitting operation and the distance measurement calculation output synchronized with the output signal, and the output signal from the terminal T3 is "H".
At level, the integrating capacitor 52 is reset. Also,
When the output signal from the terminal T4 is at "H" level, inverse integration is prohibited (step # 51).

Next, the operation of step # 51 is performed for a predetermined time of 6 ms.
Executed during ec and wait for the setting condition to stabilize (step # 5
2). Then, the output signal from the terminal T3 changes from the "H" level to the "L" level, the reset of the integration capacitor 52 is released, and the integration of the distance measurement calculation output is enabled (step # 53).

Next, in synchronization with the light emission from the light emitting element, the distance measurement calculation output is integrated by the integration capacitor 52, and the light measurement output is converted into an analog form by a light emission routine which will be described later.
/ D is implemented (step # 54). Then, inverse integration is performed to obtain the distance measurement calculation output as a count value (step #
55).

Furthermore, the level of the control signal S1 output from the control circuit section 25 becomes "H", the level of the control signal S2 becomes "L", the level of the control signal S3 becomes "H", and the distance measuring light receiving element pair The light emitting elements 2b and 1c and 1d are enabled (step # 56). Then, the timer 4 preset to 1 msec waits for the set state to stabilize for 1 msec (step # 57).

Next, when the level of the control signal S4 is "L", the level of the control signal S5 is "H", and the level of the control signal S6 is "L", the photometric output by the photometric light receiving element 2B is selected (step # 58).

After the step # 58, the timer 5 set to the predetermined time of 5 msec waits for the set state to stabilize (step # 59).

Next, the output signal from the terminal T3 of the control circuit section 25 changes from the "H" level to the "L" level, the reset of the integration capacitor 52 is released, and the integration of the distance measurement calculation output is enabled (step # 60). Next, in synchronization with light projection from the light emitting element, the distance measurement calculation output is integrated by the integrating capacitor 52, and analog conversion conversion A / D of the light measurement output is performed every time the light is projected here (step # 61). .. afterwards,
Inverse integration is performed to obtain the distance measurement calculation output as a count value (step # 62).

Next, the level of the control signal S1 output from the control circuit section 25 becomes "H", the level of the control signal S2 becomes "H", the level of the control signal S3 becomes "L", and the light receiving element for distance measurement is obtained. The pair 1e and 1f and the light emitting element 2c are enabled (step # 63). Then, the timer 4 set in advance for 1 msec waits for the setting state to stabilize (step # 64). Next, the level of the control signal S4 is "L", the level of the control signal S5 is "L", the level of the control signal S6 is "H", and the photometric output by the photometric light receiving element 2C is selected (step # 65). .. Then, the timer 5 set to a predetermined time of 5 msec waits for the set state to stabilize (step # 66).

Next, the output signal from the terminal T3 of the control circuit section 25 changes from the "H" level to the "L" level, the reset of the integration capacitor 52 is released, and the integration of the distance measurement calculation output is enabled (step # 67). Next, in synchronization with light emission from the light emitting element, the distance measurement calculation output is integrated into the integration capacitor 52, and each time the light is emitted, an analog conversion A / D of the light measurement output is performed.
Is performed (step # 68). Then, inverse integration is performed to obtain the distance measurement calculation output as a count value (step # 6).
9).

Next, referring to the flow chart of FIG.
The A / D conversion operation of the distance measurement calculation output of the light projecting operation of the second embodiment will be described.

First, the memory AD which stores the A / D converted value is initialized (step # 70). A variable K indicating the number of times of light emission is set to "0" (step # 71). An "L" level output signal is emitted from the terminal T1 of the control circuit 25. At that time, the distance measurement calculation output is integrated in synchronization with the light projection (step # 72). The light is projected for a predetermined time of 100 μsec set by the timer 3 (step # 73), and then the “L” level signal from the terminal T1 is changed to “H”.
Level, turn off the light emission, and turn on the red LED (I
Wait for 2.5 msec to cool the RED) (step # 74). The waiting time is applied to the conversion time, and the output of the distance measurement calculation is analogized by successive comparison (A / D)
It is converted and the photometric output is read (step # 75). Then, "1" is added to the variable K and incremented (step # 76).

Then, the distance measurement calculation output value ADN obtained in step # 75 is stored in the memory AD, and is stored so as to add the new distance measurement calculation output value ADN to the stored value from the second time onward. Yes (step # 77).

Next, such photometry is performed for the third time (variable K =
Until step 3), the procedure returns to step # 72 and is repeated (step # 78), and if it is the fourth time (variable K = 4) (YE
S), and shifts to the next step. The distance measurement calculation output value ADN for four times stored in the memory AD is divided by 4 to calculate the average value of the photometric values, and the average value is stored again in the memory AD (step # 79). Therefore, the photometric output is 2.
Since it is sampled four times every 5 msec and averaged, it is possible to remove the influence from disturbance such as a fluorescent lamp (cycle of about 10 msec). At the same time, variations in the photometric calculation output value are also removed.

Next, it is judged whether or not the level of the control signal S1 is "L" (step # 80), and if it is "L" level (Y
ES), the average value is stored in the memory M4 and the process is terminated (step # 81). If the level is not “L” (NO), it is determined whether the level of the control signal S2 is “L” (step # 81).
82). If the control signal S2 is "L" level in this determination (YES), after storing the average value in the memory M5,
When it is not the "L" level (NO), it is stored in the memory M6 and the process is completed (step # 83).
84).

Therefore, in the second embodiment, in the light projecting routine, the photometry is performed four times for each of the three photometry points on the screen, and the average value is stored in the memory. The lens extension and the exposure control are executed based on the photometric calculation output value with less influence of disturbance and less calculation error, and the accuracy is further improved.

As described in detail above, the distance measuring and photometric device of the present invention incorporates the processing of the calculation output of the distance measuring and photometry into the standby time occurring in the sequence of the distance measuring and photometric operations. When a plurality of distance measurement and photometry are detected, the photometry calculation output value or the photometry calculation output average value can be obtained in parallel, so that a plurality of distance measurement and photometry can be executed, and highly accurate distance measurement and photometry values can be obtained. be able to.

In the first embodiment, the A / D conversion of the photometric output is executed during the waiting time during which the light is projected a plurality of times, but the present invention is not limited to this. For example, stabilization of the photometric circuit is performed in advance. Alternatively, only the A / D conversion may be performed after the inverse integration is completed and before the distance measurement of the next area is started.

Further, the present invention is not limited to the above-described embodiments, and it is needless to say that various modifications and applications can be made without departing from the scope of the invention.

[0096]

As described above in detail, according to the present invention, it is possible to provide a highly accurate distance measuring and photometric device in which the total measuring time for a plurality of regions is shortened.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a distance measuring and photometric device as a first embodiment of the present invention.

FIG. 2 is a block diagram showing an entire electric circuit of the distance measuring and photometric device of the first embodiment.

FIG. 3 is a timing chart showing waveforms of signals supplied from the control circuit section shown in FIG.

4A to 4C show specific circuit diagrams of each unit shown in FIG.

5 (a) and 5 (b) are specific circuit diagrams of each unit shown in FIG.

FIG. 6 is a flowchart illustrating a distance measuring / photometric operation according to the first embodiment.

FIG. 7 (a) is a flowchart of an integration operation of light projection, and FIG. 7 (b) is a flowchart of an inverse integration operation.

FIG. 8 is a flowchart showing an A / D conversion operation of an integrated distance measurement calculation output.

FIG. 9 is a distance measurement characteristic diagram showing a distance measurement range from infinity to the closest distance according to the reciprocal of the object distance.

FIG. 10 is a timing chart showing the operation of the second embodiment.

FIG. 11 is a flowchart showing a distance measuring / photometering operation of the second embodiment.

FIG. 12 is an A / D of the distance measurement calculation output of the second embodiment.
It is a flowchart which shows a conversion operation.

[Explanation of symbols]

1a to 1f ... Silicon photo (SP) diode, 2a
2c ... Light emitting element (red light emitting diode), 3 ... Emitter lens, 4 ... Subject, 5 ... Distance measuring light receiving lens, 6 ... Distance measuring photometer circuit means, 7 ... Photometer element, 21 ... Projector circuit section, 22 …
Photocurrent detection circuit section, 23 ... Operation output circuit section, 24 ... Count circuit section, 25 ... Control circuit section, 26 ... Logarithmic compression circuit,
R ... resistor, C ... capacitor.

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[Procedure amendment]

[Submission date] August 20, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Details of Correction] This distance measuring and photometric device is provided with six silicon photo (SP) diodes 1a to 1f as light receiving elements. These SP diodes are (1a, 1
b), (1c, 1d), and (1e, 1f) are paired (hereinafter referred to as a light receiving element pair). For one of the light receiving element pair, infrared light emitting diodes emitting element 2a made of (hereinafter referred to as IRED), 2b, made to correspond to one of the 2c, 3 pairs is configured, the imaging screen The distance measurement is performed at three predetermined locations.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction content]

The operational amplifier 500 which constitutes the background light removing circuit section has a terminal T of the control circuit section 25 shown in FIG.
The "H" level of the output signal of No. 1 is given to the base of the transistor 600 via the resistor 730 so that it becomes active when turned on, and the background light is supplied to the capacitor 7 connected to the output terminal thereof. The charge current according to the brightness of the transistor 4 is accumulated, and the photocurrent component due to the background light of the SP diode 1a and the bias current component of the operational amplifier 3 are transferred to the transistor 4 by the feedback loop including the capacitor 7 and the transistor 4. It is discharged to the ground line as a collector current.

[Procedure 3]

[Document name to be amended] Statement

[Item name to be corrected] 0040

[Correction method] Change

[Correction content]

Similarly, in the section B of FIG. 3, the level of the control signal S1 output from the control circuit unit 25 is "H", the level of the control signal S2 is " L ", and the control signal S3.
When the level of H is " H ", the light receiving element pair 1c, 1
Distance measurement is performed by the configuration of d and the light emitting element 2b.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0056

[Correction method] Change

[Correction content]

Next, with respect to the light emitted from the light emitting element,
In synchronization, the integration calculation output is integrated into the integration capacitor 52,
Here, the A / D conversion of the photometric output is performed in parallel (step # 4). After that, inverse integration is performed to obtain the distance measurement calculation output as a count value (step # 5).

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0059

[Correction method] Change

[Correction content]

Next, the output signal from the terminal T3 of the control circuit section 25 changes from the "H" level to the "L" level, the reset of the integration capacitor 52 is released, and the integration of the distance measurement output is enabled (step # 9). Next, with respect to the light projected from the light emitting element, the distance measurement calculation output is integrated in the integration capacitor 52 in synchronism, and the A / D conversion of the photometry output is performed in parallel here (step # 10). .. Then, inverse integration is performed to obtain the distance measurement calculation output as a count value (step # 1).
1).

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0061

[Correction method] Change

[Correction content]

Next, the output signal from the terminal T3 of the control circuit section 25 changes from the "H" level to the "L" level, the reset of the integration capacitor 52 is released, and the integration of the distance measurement output is enabled (step # 15). Next, the light is emitted from the light emitting element, and the distance measurement calculation output is integrated with the integrating capacitor 52 in synchronization with the light, and the A / D conversion of the light measurement output is performed in parallel here (step # 16). Then, inverse integration is performed to obtain the distance measurement calculation output as a count value (step # 1).
7).

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0080

[Correction method] Change

[Correction content]

Next, in synchronization with the light emission from the light emitting element, the distance measuring calculation output is integrated by the integrating capacitor 52, and the A / D conversion of the light measuring output is executed by the light emitting routine described later (step # 54). After that, inverse integration is performed to obtain the distance measurement calculation output as a count value (step # 55).

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0084

[Correction method] Change

[Correction content]

Next, the output signal from the terminal T3 of the control circuit section 25 changes from the "H" level to the "L" level, the reset of the integration capacitor 52 is released, and the integration of the distance measurement calculation output is enabled (step # 60). Next, in synchronization with the projection of light from the light emitting element, the distance measuring calculation output is integrated by the integrating capacitor 52, and the A / D conversion of the photometric output is performed every time the light is projected (step # 61). Then, inverse integration is performed to obtain the distance measurement calculation output as a count value (step # 6).
2).

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0086

[Correction method] Change

[Correction content]

Next, the output signal from the terminal T3 of the control circuit section 25 changes from the "H" level to the "L" level, the reset of the integration capacitor 52 is released, and the integration of the distance measurement calculation output is enabled (step # 67). Next, in synchronization with the projection of light from the light emitting element, the distance measurement calculation output is integrated into the integrating capacitor 52, and the A / D conversion of the photometric output is performed each time the light is projected (step # 68). Then, inverse integration is performed to obtain the distance measurement calculation output as a count value (step # 69).

[Procedure Amendment 10]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03B 7/099 9224-2K

Claims (1)

[Claims] 1. A light projecting means for repeatedly projecting a light flux toward a subject a plurality of times, a distance detecting means for receiving a light flux reflected from the subject and outputting a signal according to a distance from the subject, And a control unit for controlling the photometric operation repeatedly executed by the light projecting unit so as to perform the non-light projecting between the light projecting. Distance measuring and photometric device characterized by.