JPH02197829A - distance measuring device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Application of the Invention) The present invention relates to a distance measuring device suitable for a camera, which measures a distance by detecting the brightness pattern (contrast) of a distance measuring target illuminated by an auxiliary light means. It is about improvement.

(Background of the Invention) Conventional devices of this type emit auxiliary light to artificially create contrast when measuring distance in low contrast or low brightness conditions in order to obtain correct distance measurement information. .

However, in scenes where distance measurement cannot be performed even if the auxiliary light is emitted, such as distant low-contrast scenes where the auxiliary light cannot reach, or repetitive patterns, no focusing signal can be obtained, and the auxiliary light is emitted in vain. As a result, for cameras that have a power source with limited power, such as a battery, there is a problem in that the battery life is unnecessarily shortened.

(Object of the Invention) An object of the present invention is to provide a distance measuring device that can solve the above-mentioned problems, prevent wasteful power consumption, and improve the durability of the auxiliary light means. .

(Characteristics of the Invention) In order to achieve the above object, the present invention provides the following features: when a focusing signal cannot be obtained within a distance measuring means for a predetermined time longer than the time required for multiple distance measuring operations, or when a predetermined If a focus signal is not obtained despite performing distance measurement operations a number of times, an operation control means is provided to stop driving the auxiliary light means, so that the focus signal is not obtained for a predetermined period of time or a predetermined number of times. The feature is that the emission of the auxiliary light is stopped if the condition continues that the object cannot be obtained.

(Embodiments of the Invention) Hereinafter, the present invention will be described in detail based on illustrated embodiments.

FIG. 1 is a block diagram showing a first embodiment of the present invention.

In Fig. 1, SWI is a switch that is turned on when the release switch is pressed halfway, SW2 is a switch that is turned on when the release switch is pressed fully, 2 is an inverter, and 3 is a distance measuring IC (not shown) that controls distance measurement. 4 is a photometry control circuit that causes a photometry IC (not shown) to perform photometry, 5 is an LED for auxiliary light, and 6 is a distance measurement control circuit that detects the contrast of the subject and obtains distance measurement information as is well known. Inverter, 7
8 is an AND gate that outputs "1'" when both inputs become "1", and 8 actually controls the lens barrel with the lens based on the distance measurement information obtained by the distance measurement control circuit 3. A lens barrel control circuit, 9 an exposure control circuit that actually controls a shutter (not shown) based on the photometry information obtained by the photometry control circuit 4, and 1o a winding control circuit for winding the exposed film for one frame. , 11.2 is the ranging control circuit 3. Lens barrel control circuit 8 based on the information given by the photometry control circuit 4. This is a data bus for sending data to the exposure control circuit 9.

Next, the operation will be explained.

When switch SW1 is turned on, the output of inverter 2 becomes “
The distance measurement control circuit 3 starts operating. Then, the LED 5 lights up according to the instruction from the distance measurement control circuit 3. After that, when the goldfish signal is obtained, the photometry control circuit 4 starts operating, and the distance measurement control circuit 3 starts operating. When the photometric information is obtained, the photometric control circuit 4 outputs "1" to the AND gate 7.

At this time, if the switch SW2 is on, the output of the inverter 6 is "1", the output of the AND gate 76 is "1", and the information obtained by the ranging control circuit 3 is transferred to the data bus. 11 and is taken into the lens barrel control circuit 8.

The lens barrel control circuit 8 controls the lens barrel according to the acquired information. When control of the lens barrel is completed, the exposure control circuit 9 takes in information from the photometry control circuit 4 through the data bus 12, and controls a shutter (not shown) in accordance with the information. When the shutter control is completed, the winding control circuit 10 starts operating and winds up the photographed film by one frame.

In the above configuration, an embodiment in which the emission of the auxiliary light is stopped if the distance measurement cannot be performed for a predetermined period of time to suppress power consumption will be described with reference to FIGS. 2 to 5.

FIG. 2 shows the operation timing in the distance measurement control circuit 3.

The "H" timing of the distance measurement operation is the period in which the IC is operated to perform distance measurement, and in this embodiment, six distance measurements are performed, three of which are when the auxiliary light is emitted. Tl and T2 are internal timers, and T2 is a timer for stopping the auxiliary light emission if distance measurement is not possible for a predetermined period of time.
T1 is a timer that stops the distance measurement operation if distance measurement is not possible for a certain period of time. In Fig. 2, the timer T is
1 is activated, and then the distance measuring operation is interrupted.

FIG. 3 is a flowchart showing the operation of the first embodiment of the present invention.

In step 31, timer T1 is set, and in step 32, timer T2 is set. In step 33, the auxiliary light is started to emit (starts lighting up the LED 5), and in step 34, distance measurement is performed while the auxiliary light is emitted.In step 35, it is determined whether or not a focus signal has been obtained, and the focus is If not, it is determined in step 36 whether or not the timer T2 has finished counting the predetermined time. If the timer T2 has not finished counting, the process returns to step 33 and distance measurement is performed with the auxiliary light emitting, until the timer T2 finishes counting (when focus information is obtained). (If not, repeat the above steps.)

When it is determined in step 36 that the timer T2 has finished counting, the process proceeds to step 37, where it is determined whether the timer T1 has finished counting the predetermined time. If the result is not completed, the process returns to step 34, and distance measurement is performed without emitting the auxiliary light.If the focus signal is not obtained even after the timer T1 expires, the process proceeds to step 38, and the distance measurement is performed without emitting the auxiliary light. After the information is captured, the process proceeds to step 39 for obtaining photometric information, as in the case where a focus signal is obtained in step 35.

In step 39, the photometry control circuit 4 is operated to obtain photometry information at that point, and then the process proceeds to step 40, in which the lens barrel control circuit 8 is operated to control the lens barrel in accordance with the distance measurement information. In step 41, exposure control is performed according to the photometric information, and in step 42, the film of the l portion exposed in step 41 is wound.

FIG. 4 is a flowchart showing the operation of the second embodiment of the present invention, and the same parts as in FIG. 3 are given the same step numbers.

In step 50, it is determined whether the switch SWI is turned on, and if it is turned on, timer T1 is set, and step 32
Set timer T2. Thereafter, steps 33 to 37.
The operations at 39 to 42 are the same as described above, so the details will be omitted.

When it is determined in step 37 that the time measurement by the timer T1 has ended, the process proceeds to step 52 to stop the distance measuring operation, and then waits for the switch SWI to turn off in step 51.
When the switch SWI is turned off, the process returns to step 50.

In the second embodiment, the release is locked until a focus signal is obtained, and even after the timer TI expires, the distance measuring operation is simply stopped and the release is resumed as shown in the flowchart of FIG. There isn't.

FIG. 5 is a flowchart showing the operation of the third embodiment of the present invention, and the same parts as in FIGS. 3 and 4 are given the same step numbers.

The difference from the second embodiment shown in FIG. 4 is that if the switch SWI is not turned off in step 51, the timers Tl and T2 are set again in steps 31 and 32, and the ranging operation is repeated. It is. That is, as long as the switch SWI is on, the distance measuring operation is repeated at the interval of the timer T1.

Next, the sixth example shows an example in which the emission of the auxiliary light is stopped if the distance measurement failure state continues for a predetermined number of times to reduce power consumption.
This will be explained using FIGS. 9 to 9.

The circuit configuration is the same as that shown in FIG. However, the first
In the ranging control circuit 3 in the embodiments 3 to 3, there are timers TI and T.
2, and in the fourth to sixth embodiments described below, a counter is provided for counting the number of distance measurements.

FIG. 6 shows the operation timing in the distance measurement control circuit 3.

The "H" timing of the distance measurement operation is the period during which the IC is operated to perform distance measurement, and in this embodiment, six distance measurements are performed, and the auxiliary light is emitted for three of them. It is shown that. Counter Kl.

K2 is a counter, K2 is a counter that stops the auxiliary light emission when distance measurement is not possible for a predetermined number of times (3 times in the following example), and K1 is a counter for stopping distance measurement for a certain number of times (6 times in the following example). This is a counter that stops the distance measurement operation. FIG. 6 shows that the distance measuring operation is interrupted by performing the distance measuring operation six times.

FIG. 7 is a flowchart showing the operation of the fourth embodiment of the present invention.

Step 61 sets the counter to 1, and step 62
Set 2 on the counter. In step 63, the auxiliary light starts emitting, and in step 64, distance measuring operation is performed while the auxiliary light is emitted.In step 65, it is determined whether a focus signal is obtained, and if the focus is not achieved, , step 66
It is determined whether the contents of 2 have reached a predetermined number of times in the counter. If the content of 2 does not reach the predetermined number of times in the counter, the process returns to step 63 and the distance measurement operation is performed with the auxiliary light emitting, until the content of 2 in the counter reaches the predetermined number of times (focus signal (if not obtained) repeat the above operation.

When it is determined in step 66 that the content of 2 has reached a predetermined number of times in the counter, the process proceeds to step 67, and it is then determined whether the content of 1 in the counter has reached a predetermined number of times. If the result has not been reached, the process returns to step 64 and distance measurement is performed without emitting the auxiliary light. If the in-focus signal is not obtained even if the content of 1 reaches the predetermined number of times in the counter, step 68 As in the case where the process proceeds to Step 65, the fixed point information is acquired, and the focus signal is obtained in Step 65,
The process advances to step 69 for obtaining photometric information.

In step 69, the photometry control circuit 4 is operated to obtain photometry information at that point, and then the process proceeds to step 7o, where the lens barrel control circuit 8 is operated to perform lens barrel control according to the distance measurement information.Step 71 Then, exposure control is performed according to the photometric information, and in step 72, the 1 exposed in step 71 is
Winds the film for each frame.

FIG. 8 is a flowchart showing the operation of the fifth embodiment of the present invention, and the same parts as in FIG. 7 are given the same step numbers.

In step 80, it is determined whether the switch SWI is turned on, and if it is turned on, a counter is set to 1, and in step 6
2 sets the counter to 2.

Since the operations in steps 63 to 67 and 69 to 72 are the same as described above, the details thereof will be omitted.

When it is determined in step 67 that the counter has reached the predetermined number of times of 1, the process proceeds to step 82 to stop the distance measuring operation, and then in step 81 waits for the switch SWI to turn off. Then step 8
Return to 0.

In the fifth embodiment, the release is locked until a focus signal is obtained, and the counter is set to 1 a certain number of times (6 times).
Even if the distance measurement operation reaches , the distance measuring operation is simply stopped and the release is not performed as shown in the flowchart of FIG.

FIG. 9 is a flowchart showing the operation of the sixth embodiment of the present invention, and the same parts as in FIGS. 7 and 8 are given the same step numbers.

The difference from the fifth embodiment shown in FIG. 8 is that if the switch SWI is not turned off in step 81, the counter 1. This is the part where 2 is set for each and the distance measurement operation is repeated. That is,
As long as the switch SWI is on, the distance measuring operation is repeated at intervals when the counter is incremented by 1, that is, every 6 times.

According to this embodiment, if the state in which distance measurement is not possible continues for a predetermined period of time or a predetermined number of times, the emission of the auxiliary light is stopped and the distance measurement operation continues without the auxiliary light, so that unnecessary light emission is avoided. This makes it possible to improve the durability of the auxiliary light, and also to reduce the power consumption required to emit light, making it particularly effective for cameras with limited power, such as batteries.

(Correspondence between the invention and the embodiments) In this embodiment, the lamp 5 is the auxiliary light means of the present invention.
The distance measurement control circuit 3 corresponds to distance measurement means. Further, the portion that performs the operations of step 36 in FIGS. 3 to 5 and step 66 in FIGS. 7 to 9 is the operation control means of claim 1.2, and the first operation control unit of claim 3.4. means, third
The portion that performs the operations of step 37 in FIGS. 7 to 5 and step 67 of FIGS. 7 to 9 respectively correspond to the second operation control means of claim 3.4.

(Modification) In this embodiment, an LED is used as the auxiliary light, but a light emitting means such as a thermal lamp or a strobe may also be used.

(Effects of the Invention) As explained above, according to the present invention, when a focus signal is not obtained for a predetermined time longer than the time required for multiple distance measurement operations, or when the distance measurement operation is performed a predetermined number of times, If a goldfish signal cannot be obtained in spite of this, an operation control means is provided to stop the driving of the auxiliary light means, and if a state in which a focusing signal is not obtained for a predetermined period of time or a predetermined number of times continues, , Since the auxiliary light emission is stopped, unnecessary power consumption is prevented.
Furthermore, the durability of the auxiliary light means can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a diagram showing the relationship between distance measuring operation, light emitting operation, and each timer in the first to third embodiments, and FIG. 3 is a block diagram showing one embodiment of the present invention. FIG. 4 is a flowchart showing the operation of the second embodiment of the present invention, and FIG. 5 is a flowchart showing the operation of the second embodiment of the present invention.
A flowchart showing the operation of the embodiment, FIG. 6 shows steps 4 to 6.
FIG. 7 is a flowchart showing the operation of the fourth embodiment of the present invention, and FIG. 8 is a diagram showing the relationship between the distance measurement operation, the light emission operation, and each counter in the sixth embodiment, and FIG. 8 is the fifth embodiment of the present invention. FIG. 9 is a flowchart showing the operation of the sixth embodiment of the present invention. 3... Distance measurement control circuit, 4... Light metering control circuit, 5... LED, 8... Lens barrel control circuit, SWI, SW2... ···switch.

Claims (4)

[Claims] (1) An auxiliary light unit that is driven every time a distance measurement operation is performed and projects auxiliary light toward a distance measurement target, and detects the brightness pattern of the distance measurement target illuminated with the auxiliary light to obtain distance measurement information. , Part 1
In a distance measuring device equipped with a distance measuring means that repeats the distance measuring operation when a focusing signal cannot be obtained in the distance measuring operation once, the distance measuring means is provided with a 1. A distance measuring device comprising: an operation control means for stopping driving of the auxiliary light means when a focusing signal is not obtained for a predetermined time longer than the above-mentioned time. (2) An auxiliary light unit that is driven every time a distance measurement operation is performed and projects auxiliary light toward a distance measurement target, and detects the brightness pattern of the distance measurement target illuminated with the auxiliary light to obtain distance measurement information. , Part 1
In a distance measuring device equipped with a distance measuring means that repeats the distance measuring operation when a focusing signal is not obtained in the distance measuring operation, the distance measuring means repeats the distance measuring operation a predetermined number of times. 1. A distance measuring device comprising: an operation control means for stopping driving of said auxiliary light means when a focusing signal cannot be obtained despite the above conditions. (3) An auxiliary light unit that is driven every time a distance measurement operation is performed and projects auxiliary light toward a distance measurement target, and detects the brightness pattern of the distance measurement target illuminated with the auxiliary light to obtain distance measurement information. , Part 1
In a distance measuring device equipped with a distance measuring means that repeats the distance measuring operation when a focusing signal cannot be obtained in the distance measuring operation once, the distance measuring means is provided with a a first operation control means for stopping the driving of the auxiliary light means when a focusing signal is not obtained for a first predetermined time period longer than the first predetermined time period; A distance measuring device comprising a second operation control means for stopping a subsequent distance measuring operation if a focusing signal is not obtained for a second predetermined time period which is a long time required for the distance measuring operation. (4) An auxiliary light unit that is driven every time a distance measurement operation is performed and projects auxiliary light toward a distance measurement target, and detects the brightness pattern of the distance measurement target illuminated with the auxiliary light to obtain distance measurement information. , Part 1
In a distance measuring device comprising a distance measuring means that repeats the distance measuring operation when a focusing signal is not obtained in the first distance measuring operation, the distance measuring means includes a first predetermined number of distance measuring operations. a first operation control means for stopping driving of the auxiliary light means when a focusing signal is not obtained despite performing the above;
1. A distance measuring device comprising a second operation control means for stopping a subsequent distance measuring operation if a focusing signal is not obtained a second predetermined number of times greater than the second predetermined number of times.