JPS5856809B2 - distance detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for detecting the distance between a photographic flash device or the like and an object.

Conventionally, various means for detecting the distance to an object have been devised and put into practical use.

For example, the double f-quadrant matching method is widely used as a distance measurement method in optical equipment, but this method is purely optical (although it has a relatively simple configuration, Therefore, it was not possible to expect high measurement accuracy in order to discriminate the measurement results.

In particular, when the state of the object to be measured changes continuously, or when the object is in the dark, there is a drawback that it is not possible to easily confirm the state of coincidence between the two.

In order to eliminate these drawbacks, the special public
As shown in Japanese Patent Application No. 330, No. 50-29349, etc., distance detection means combining optical means and electrical means have been proposed.

In both of these inventions, the light from a flashlight such as a flash lamp is used as a distance measuring light to form a beam through a slit and a projection lens, and is irradiated onto the object whose distance is to be detected, and the reflected light from the object is transmitted through the projection lens. A photo-sliding resistor consisting of two electrodes, a part made of a photoconductive material with a fast photoresponse speed such as CdSe, and a resistor sandwiching this part; that is, a resistor whose resistance value changes depending on the position of the light. The distance to the subject is directly converted into the resistance value of the upper light distributing sliding resistor to detect the distance.

However, with this distance detection method, unless the light resistance of the optical sliding resistor, which is the light receiving element, is extremely small, it is difficult to accurately match the position of the light to the distance to the subject. It is not possible to make a correspondence.

In other words, even if the irradiated light is small, ideally the resistance value of the irradiated part should be zero.
Only when it becomes zero does the resistance value, which changes depending on the position of the light, become associated with the distance to the subject.

In other words, the operations of the invention described above are all based on the assumptions described above.

However, as a practical matter, it is of course impossible to set the conditions (assumptions) as described above, and the resistance value at the position hit by the light is greatly influenced by the intensity of the hit light.

For this reason, in the above-mentioned invention, a flash device, which produces a large amount of light, is used as the projector, but it still has the following problems.

In other words, when considering objects that are at the same distance but have different light reflectances, the intensity of the light will differ even if the light is received at the same location. The resistor may output a different resistance value, and the operation of the invention disclosed in the above-mentioned publication, which uses the resistance value output by the optical sliding resistor as direct distance information, has a high risk of malfunction. .

Furthermore, even if the above-mentioned conditions are set (and this results in a very favorable result), it becomes impossible to ignore the effects of light other than the flash, and a new problem arises, such as the inability to perform distance detection at all. There is a risk that this may occur.

The present invention has been made in consideration of the above-mentioned points, and has a major feature in that the light receiving operation of reflected light from a subject is ρ. The distance is detected by comparing the amount of light received by each of the plurality of light receiving elements and detecting the light receiving element that receives the maximum amount of light. Or, to provide a distance measuring device that is not affected by other light at all, uses the detection of a light receiving element as an output signal, and can easily compensate for variations between light receiving elements, which can be easily amplified. It is.

FIG. 1 is a schematic diagram of the configuration of a distance measuring device according to the present invention. In the figure, 1 indicates a flash discharge tube 2, a reflector 3, a slit hole 4 provided in front of the flash discharge tube 2, and a slit hole 4 provided in front of the flash discharge tube 2. The light-emitting part of the light-emitting device has a lens system 5 for focusing the flash light that has passed through the light into a narrower beam, 6 is the object whose distance is to be measured, and 7 is the light emitting unit of the light-emitting device 1. A light receiving element group 8 arranged in a direction perpendicular to the slit hole 4 that receives reflected light from the object 6, and a lens system 9 provided in front of this light receiving element group 8.
The light receiving sections of the light receiving device each having a light receiving device are shown.

FIG. 2 shows an optical line diagram for explaining the principle of detecting the distance of the schematic configuration diagram shown in FIG. The position of the lens system 5 to focus on, that is, the emission position of the flash, B is the position of the subject in the case of close range, and C is the position of the subject in the case of long distance.
D is the lens system 9 in front of the light receiving element group 8 shown in FIG.
, that is, the light receiving position of the reflected light, E indicates the position of the light receiving element group 8, and 11 and 12 indicate the individual positions of the light receiving elements of the light receiving element group 8.

θ1. θ2 is the point t of B and C, which depends on the light emission l of the light emitting unit 1.
The angles at which the light reflected from a certain object is received by the light receiving element group 8 are shown.

Now, in Figure 2 1, the object at point B, which is a short distance away, is tanθ1-tanθ.

It is clear from the drawing that the following relationship holds true.

Therefore, the position of the light receiving element 11 that receives the reflected light from the object at point B is shown in the following relationship.

In other words, the distance to the object is expressed as a function of I.

Similarly, if we consider the object at point C, which is far away, then, the position of the light receiving element 12 that receives the reflected light from the object at point C is the distance AC to the object at point C. It can be expressed as a function of

Therefore, if the distance AD between the light emitting section 1 and the light receiving section 7 and the focal length DE of the lens system 9 of the light receiving section 7 are arbitrarily set in the configuration ζ shown in FIG. This distance can be easily determined by knowing which light receiving element in the light receiving element group 8 received the reflected light from the unknown object.

In other words, the light-receiving elements of the aforementioned light-receiving element group 8 can be arranged at arbitrary intervals, and it is confirmed in advance which light-receiving element will receive the reflected light from the object located at an arbitrary distance. For example, if the output of the light-receiving element that has received the maximum amount of reflected light in the light-receiving element group 8 is used as a signal to operate a display device such as a light-emitting display element through an amplifier or the like, the distance to the object can be displayed. That's why it happens.

As is clear from the drawing, the optical diagram showing the principle of distance detection shown in FIG. is located within a plane perpendicular to the light emitting axis of the light emitting part 1 (although D is positioned in the horizontal and vertical directions with respect to Al), There is no problem as long as the light emitting section 1 and the light receiving section 7 are set so that it is possible to recognize how far away they are from each other.

Let's consider an example here.

Now, if we set the distance between the light emitting unit 1 and the light receiving unit 7 as AD = 101, the focal length DE of the lens system 9 of the light receiving unit 7 = 28 mm, and the distance to the object AB = 1 m, the center of the light receiving element group 8 Among the light-receiving elements, the light-receiving element located at a distance of receives the reflected light from the light emitting unit 1 from the object at a distance of l'rI'L.

Similarly, if the distance to the object is AB = 2 m, then the following values will be obtained.If we consider the combination below, we can obtain the following values for the objects of 5 m and 10 m, respectively.

Here, as is clear from the above calculation results, the farther the distance to the object is, the closer the position of the light receiving element is to the optical axis.

Therefore, if the arrangement of the light-receiving element group 8 is set based on the light-receiving element position of 0.28 x 10-3 m, if the farthest distance to be measured is 10 m in the above-mentioned example, then 10771 [Regarding this, by detecting the light-receiving element that receives the light reflected from the target object, you can easily find out the distance to the target object by performing a display operation that corresponds to the calculation results described above. I can do it.

That is, for example, if the distance to the target is 57 rL, the light receiving element located 0.56 mm away from the optical axis of the light receiving element group 8 will not receive the reflected light, so the distance between the two is 0.5 mm. If the light receiving output is obtained from the light receiving element, the display operation for indicating 5rrL can be performed using the light receiving output.

It should be noted that, as is clear from the operations described above, that is, the detection of the light-receiving element into which the maximum amount of reflected light from the object is input, or the distance calculation principle shown in the above-mentioned formula, the light emitting device 1 illuminates the object. By making the flash light as narrow as possible, by increasing the focal length of the lens system 9 used in the light receiving device 7, and by making the interval between each light receiving element in the light receiving element group 8 as small as possible, more accurate distance detection is possible. Needless to say, it will happen.

In addition, as shown in the figure, the perpendicular arrangement of the slit hole 4 and the light receiving element group 8 improves the light receiving characteristics of the light receiving element group by spreading the reflected light from the subject 6, that is, reduces the number of light receiving elements that receive light as much as possible. This is intended to further improve distance detection accuracy.

As described above, the present invention irradiates an object with a narrow beam of flash light from a light emitting device through a slit hole, and the reflected light from the object due to this irradiation is transmitted to the fixed focal point of the optical system through the above slit. The principle is to receive light from a group of light-receiving elements ρ arranged perpendicularly to the hole, and to detect the distance to the above-mentioned object based on the light-receiving output of this group of light-receiving elements. The circuit portion of the distance detecting device, which is a feature of the present invention, will be described, such as the detection circuit that detects which light-receiving element receives the reflected light from the subject.

FIG. 3 shows two embodiments of the electric circuit of the distance detecting device according to the present invention.
, a trigger circuit 13, a flash discharge device F consisting of a flash discharge tube 14 as a light source, a voltage generation circuit G that generates a voltage in synchronization with the light emission, and a voltage generation circuit G that receives reflected light from the subject and calculates the amount of received light and electricity. A plurality of light receiving circuits H...Hn including a light receiving element that converts into a quantity, a plurality of comparators ■...
・In, multiple display circuits J showing comparator output...
...Jn, comparator I...In, display circuit J...
. . . It is composed of a control circuit K that controls the operation of Jn, and a power supply section that supplies voltage to each of the above-mentioned circuits.

In the circuit configured as described above, the flash discharge tube 14 emits light due to the operation of the intermittent photodischarge device, and as described above, the flash light is irradiated onto the subject via the slit hole 4 and the lens system 5, and at the same time Consider a case where, after the voltage generating circuit G starts operating, the light receiving element 15 of the light receiving circuit H receives the maximum amount of light reflected from the subject due to the light emitted from the flash discharge tube 14 among the many light receiving elements. The photoelectric RGC supplied via this light receiving element 15 causes the resistor 16a to
The voltage drop occurring across the operational amplifier 17 is supplied to the non-inverting input terminal l of the operational amplifier 17, and its amplified output l is supplied to the re-diode 1.
8, the integration capacitor 19 is charged.

Therefore, it goes without saying that the charging voltage of the integrating capacitor 19 corresponds to the amount of light received by the light receiving element 15.
. . . is supplied to the non-inverting input terminal of the comparator 21, which is - in In.

On the other hand, the voltage generated by the voltage generating circuit G, which starts operating in synchronization with the light emission of the flash discharge tube 14, is generated by the light receiving circuit H...
Hn? At the same time when this is supplied, the transistor 309 is also supplied via the resistor 31, so the transistor 309 is also supplied via the resistor 31.
is made conductive.

When the transistor 30 becomes conductive, the transistor 29, which had been conductive until then, becomes non-conductive.
At the same time, the transistor 28 is also made non-conductive.

Therefore, the charging operation of the capacitor 32, which had been charged by the power supply 26 through the transistor 28, stops, and the charge stored in the capacitor 32 begins to be discharged through the resistor 33.

By the way, since the high potential side of the capacitor 32 is connected to the inverting input terminal of the above-mentioned comparator 21 as shown in the figure, this comparator 21 is charged with an integral charge according to the amount of light received by the above-mentioned light receiving element 15. The operation is controlled by the charging voltage of the capacitor 18 and the charging voltage of the capacitor 32.

That is, the charging voltage of the capacitor 32 is the same as that of the integrating capacitor 19.
, the output of the comparator 21 is ``L''
When the voltage becomes lower than the charging voltage of the integrating capacitor 19 due to the discharge of the capacitor 32 progressing through the resistor 33, the output becomes ``High level I+'' and is inverted.

The output of the comparator 21 is °゛HH level +1. When the switch is turned on, the monostable multi-bi break circuit 22 starts operating and supplies the base current of the transistor 24 through the resistor 23 for an arbitrary period of time to make the transistor 24 conductive, so that the LED 25, which is a light emitting display element, turns on. Become.

Furthermore, since the transistor 27 is made conductive at the same time as the monostable multi-bi break circuit 22 starts operating, the transistor 28, which had been kept non-conductive due to the transition of the transistor 29 to the non-conductive state, becomes conductive again. Therefore, the aforementioned capacitor 321 is rapidly charged again, that is, it returns to the state ρ before the flash discharge tube 14 started emitting light.

Also, the charging voltage of the integrating capacitor 19 is the same as that of the flash discharge tube 1.
After the flash discharge tube 14 ends, the charged charge is discharged through the resistor 20, so the next flash discharge tube 14 is activated after an arbitrary period of time.
In other words, the capacitor 32 returns to its original state in the same manner as the operation of the capacitor 32 described above.

The operation as described above is the basic operation of the electric circuit of the distance detecting device according to the present invention. Comparator, monostable multi-bi break circuit,
Naturally, the light emitting display elements are different, and based on the principle described in FIGS. 1 and 2, the distance to the subject can be easily and accurately determined from the difference in the light emitting display elements.

In this way, it is possible to operate reliably using the light receiving element that has emitted the maximum output, and it is possible to accurately measure distance regardless of the reflectance of the subject and the intensity of the light source.

3. It should be noted that, as a matter of course, light receiving elements other than the light receiving element 15 illustrated in FIG. Because it is supplied through the common line to the inverting input terminal of the comparator corresponding to the light receiving elements other than 15 (
When the charging voltage of the integrating capacitor, which is charged in accordance with the amount of light received by each of the light receiving elements, becomes higher than the charging voltage of the capacitor 32, the above-mentioned comparator changes its output level from L''!HI+, Needless to say, efforts are being made to reverse this.

However, among the operations described above, considering the comparison operation in the comparator, the charging voltage of the integrating capacitor is compared with the charging voltage of the capacitor 32 that gradually drops from a constant value according to the amount of light received by each light receiving element. Therefore, it is clear that the comparator connected to the integrating capacitor charged to the highest voltage initially performs an inverting operation; Due to the operation of the multi-bye break circuit, capacitor 3 is immediately
2 is returned to the charging state again, so at the same time (
The plurality of comparators will not perform an inversion operation, that is, the plurality of light emitting display elements will not light up at the same time to provide an incorrect distance display.

As described above, the present invention includes a light emitting device that emits a narrowly narrowed flash of light, and a light receiving device that includes a group of light receiving elements arranged in a row perpendicular to the slit hole that narrows the flash of the light emitting device. The present invention provides a distance detecting device that detects the light receiving element receiving the maximum amount of light by comparing the amount of light received by the husband and wife of the light receiving element group with a reference voltage that decreases with time, and displays the distance using a light emitting display element or the like. , reflectance of the object,
Accurate distance measurement can be performed without being affected by the intensity of the light source, etc.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of the distance detection device in which the invention is made; Fig. 2
The figure is a diagram of the principle of distance detection by the distance detection device according to the first aspect of the present invention, and FIG. 3 is a diagram of one embodiment of the electric circuit of the distance detection device according to the present invention. 1... Light emitting device, 2... Flash discharge tube,
4...Slit hole, 5...Optical system, 7
. . . Light receiving device, 8 . . . Light receiving element group, 9
...Optical system, 15... Light receiving element, 19
... Integrating capacitor, 21 ... Comparator, 22 ... Monostable multi-vibration circuit, 2
4...Transistor, 25...Display element, 32...Capacitor, 27, 28, 29,
30...Transistor.

Claims (1)

[Scope of Claims] 1. A light source that irradiates a flash of light onto an object, a light emission control circuit for this light source, a slit hole provided in the front face of the light source, and a method that narrows the flash of light from the light source that passes through the slit hole. a light-emitting device configured to include an optical system for focusing, and a direction in which the slit hole is formed and an optical axis direction of the light-emitting device that receives reflected light from the object due to a flash of light from the light-emitting device; A light-receiving element group consisting of a plurality of light-receiving elements arranged in a single row, and an optical system provided so that the light-receiving element group is positioned in front of the light-receiving element group (hereinafter, the light-receiving element group is located on a fixed focal point). a comparison means for comparing the amount of light received by each of the light receiving elements of the light receiving element group with a fluctuating reference level; and an output l of the comparing means to stop the fluctuation of the reference level and to reduce the amount of light received by the light receiving element. a detection circuit system for detecting the light receiving operation of the light receiving element group, which includes a control means for controlling the operation of the display element group corresponding to the element group; A distance detection device characterized in that the distance to the target object is detected by detecting the light receiving element outputting the maximum light receiving output among the light receiving elements of the light receiving element group that receives reflected light from the object. 2. Comparison. The means includes a plurality of light receiving circuits that charge a plurality of integrating capacitors corresponding to each light receiving element that converts the amount of light received by each light receiving element of the light receiving element group into an amount of electricity, and a plurality of light receiving circuits that charge a plurality of integrating capacitors corresponding to each of the light receiving elements, and a light emitting device that simultaneously emits light from the light emitting device. A reference voltage generation circuit having a capacitor whose discharge is started by a switching circuit that starts an operation, and a charging voltage of the plurality of integrating capacitors and a charging voltage of the capacitor of the reference voltage generation circuit are compared. The distance detection device according to claim 1, comprising a plurality of comparison circuits. 3. The control means includes an oscillation circuit operated by the output of the comparison means, and an output of the oscillation circuit (the operation of which is controlled by the output of the oscillation circuit). Claim 1, comprising: a first switch element that controls fluctuations in the reference level; and a second switch element whose operation is controlled by the output of the oscillation circuit and controls the display operation of the display element group. Distance detection device described herein.