WO2001020253A1 - Method and apparatus for searching for object with speckle pattern light - Google Patents

Abstract

A speckle pattern light reflected from the surface of an object is received and the approach or presence of the object is detected without regulating the sensitivity volume regardless of the distance to the object, the surface inclination, reflectance or size of the object. A beam coherent light (2) modulated intermittently with low frequency is projected into a space to be monitored and a returned speckle pattern light (4) is transduced photoelectrically. A resulting signal current is amplified by a logarithmic amplifier and only the modulated frequency component is extracted by a DC reproducer. The voltage of the component is compared with a comparison voltage, and a detection signal (7) is outputted when the relation of magnitude is between both voltages reverved.

Description

 Description Target object detection method and device using speckle pattern light

 According to the invention of this application, the presence of a target in the same space is detected in a non-contact manner by projecting a beam-shaped coherent light onto the monitored space and receiving a speckle pattern light coming from the same space. The present invention relates to a method and an apparatus for detecting a target that can be used.

 In particular, when the inclination of the target surface with respect to the beam-like coherent light (that is, the angle formed by the normal of the target surface with respect to the beam-like coherent light) is extremely large, or Regardless of whether the light reflectance of the target surface is very small or the distance to the target surface is relatively large, the speckle pattern light coming from those target surfaces is received. The present invention relates to a target detection method and apparatus capable of detecting the presence of a target in the same space in a non-contact manner.

 Here, the “speckle pattern” is a pattern of bright and dark spots generated when light having good coherence such as laser light is scattered and reflected or transmitted on a rough surface. (Revisit this.) Background art

 Object detection devices that detect the presence or absence of an object using the reflection of light from the object are roughly classified into the following two types.

(1) The first object detection device irradiates non-coherent light toward the monitored space, and when the reflected light generated by the non-coherent light is received, the object has entered or existed in the same space. Judge. (Such devices are, for example, Under the trade name "Sensor").

 (2) The second object detection device projects a beam of coherent light toward the space to be monitored, and when it receives the specularly reflected light generated by it, the object is detected in the same space. Is determined to have entered or existed. Incidentally, coherent light has the advantage that the spot diameter on the irradiated surface can be reduced to a minimum. (These devices are generally sold, for example, under the trade name “Laser Photoelectric Switch”).

 A sheet meandering detection system that uses two object detection devices to detect the meandering of a traveling sheet is roughly classified into the following two types.

 (3) One (when) object detection device is arranged near the inside of a predetermined side line of a predetermined traveling road, and another object detection device is arranged near the outside of the predetermined side line, and When both detectors are turned on or off, it is determined that meandering has occurred. However, if the running sheet is dark blue, a reflector is placed in the space on the opposite side, and the regenerative reflected light from the reflector is used.

 (4) One object detection device is placed on both sides or both sides of both sides of the specified road, and meandering occurs when one of the detection devices is turned on or off. Is determined. If the running sheet is dark black, the same as (3) above.

 In addition to the above, the idea of an object movement (speed) measuring device using coherent light (filed on October 8, 1993) is also known.

The idea of the measuring device is to irradiate a spotted object with a spotlight of about 1.5 x 2 mm to a moving object, and to generate a one-dimensional spot pattern light generated by the irradiation. An image sensor (or a two-dimensional CCD camera) photoelectrically converts the analog signal into an electrical analog signal. The analog signal is converted into a digital signal sequence composed of 1 and 0 by a speckle pattern analysis circuit. The amount of movement (or speed) of the signal sequence is calculated and the amount of movement of the object is measured.

 The structure and function of the measurement device differ from those of the object detection device in that it uses speckle pattern light.

 The first object detection device has the following problems.

 (a1) As the size of the target object becomes smaller (for example, as thin as a wire), the detectable distance becomes shorter. '

 (a2) When the light reflectivity of the target object surface decreases (for example, deteriorates like black carbon), the detectable distance decreases.

 (a3) As the size of the target object decreases and the light reflectance of the surface decreases, the detectable distance further decreases. For example, the detectable distance for black carbon with a size of 2 mm x 2 mm is at most about 20 mm.

 (a4) The gray level between the black level and the white level cannot be detected with a single device.

 The second object detection device has the following problems.

 (b1) The detectable distance range of the object is limited. Therefore, it is impossible to detect an object located at a short distance before the distance range or an object located at a long distance beyond the distance range.

 (b2) If the tilt of the target object surface with respect to the beam-shaped coherent light becomes large, detection becomes impossible.

 (b3) It is difficult to detect objects with low light reflectance (ie, light-absorbing or light-transmitting objects).

(b4) No gray level can be detected with a single device. The third sheet meandering detection device has the following problems.

 (c1) It is impossible to reduce the number of object detection devices used to one.

 (c2) Therefore, manufacturing costs and installation costs cannot be reduced.

 (c3) Reflected light from one device may enter another device and cause a malfunction.

 The fourth sheet meandering detection device has the same problems as the above (c1) and (c2). Disclosure of the invention

 Therefore, the first object of the invention of this application is to use a beam-shaped coherent light to adjust a target located at a short distance and a target located at a long distance without adjustment and equality. Another object of the present invention is to provide a method and apparatus for detecting a target, which can detect the target.

 A second object of the invention of this application is to reliably detect the target even if the inclination of the surface of the target with respect to the provisional (taito) beam-shaped coherent light changes greatly. It is an object of the present invention to provide a method and apparatus for detecting a target.

 A third object of the invention of the present application is to detect a target having a high light reflectance and a target having a low light reflectance without any adjustment and equally. An object of the present invention is to provide a detection method and device.

A fourth object of the invention of the present application is to provide a method and apparatus for detecting a target that can detect a target having a large size and a target having a small size equally and without adjustment. To provide. A fifth object of the invention of the present application is to provide a single target detecting device capable of detecting a black level, a white level, and a gray color level.

 A sixth object of the invention of the present application is to provide a meandering state of a colorless transparent or black opaque sheet or a wobble of these edges without using two object detecting devices. An object of the present invention is to provide an edge position detection system for a running seat capable of detecting a state.

 A seventh object of the invention of the present application is to realize the above-described various object detection devices or the edge position detection system of the sheet with low light output, low operating voltage, small size, and low cost. is there.

 In order to solve the above-mentioned problems and to achieve the above-mentioned objects, the first embodiment of the target detecting apparatus using the speckle pattern light of the invention of the present application is directed to a low frequency A projector 5 for projecting a beam-shaped coherent light 2 intermittently modulated by the

 A receiver 6 for receiving any reflected light including the speckle pattern light 4 coming from the monitored space;

 Containing

Projector 5 contains the low-frequency oscillator 5 _4, a laser diode 5 _2, projection optical science system 5, the city,

Low-frequency oscillator 5 ₄ outputs the low-frequency modulation signal, the low frequency modulation signal intermittently at low frequencies the power supply circuit of the laser die Hauts de 5 _2,

And I connexion, laser diode 5 ₂ outputs the co heating les down bets light intermittently modulated at a low frequency,

The light-projecting optical system 5 collects the coherent light intermittently modulated at the low frequency and converts it into the beam-shaped coherent light 2 intermittently modulated at the low frequency. Photodetector 6, a photoelectric converter 6 ₂ contains a logarithmic amplifier 6 _3, the DC regenerator 6 _4, a comparator 6 _5, and a comparison voltage generator 6 _6,

The photoelectric converter 6 _2, any reflected light including speckle pattern light 4 arriving on the light-receiving surface and photoelectrically converts and outputs an electric analog signal,

Logarithmic amplifier 6 _3, when the amplitude of the electrical analogue signal is small makes the extension amplification, when a large becomes is to compression amplification Outputs an extended or compressed signal,

DC regenerator 6 ₄ are both when blocking the DC component in the extended or compressed signal, rectifying the modulation frequency component in the signal, and smoothed, Outputs reproduction DC signal,

Inverting input terminal of the comparator 6 ₅ (-), said reproduction DC signal voltage is applied to the non-inverting input terminal (+), the comparison voltage of the comparison voltage generator 6 ₆ is marked pressurized, the two voltages when the magnitude relationship is inverted, the comparator 6 _5, entering young properly of the target 1 in monitored space and outputs a detection signal 7 for notifying the existence was this,

 Things.

 A second embodiment of the target detecting apparatus using speckle pattern light according to the invention of the present application is the first embodiment of the target detecting apparatus using speckle pattern light,

The DC regenerator 6 ₄ has an input terminal I, the output terminal, and ground terminal element, as well as the reverse rectifying diode D in series branch, and two terminals smoothing circuit (C in parallel branches, · R> )

 The two-terminal smoothing circuit (C, -R>) consists of a parallel connection circuit of a smoothing capacitor C, and a discharge resistor R,

The input terminal I is connected to the cathode terminal of the reverse rectifier diode, and the anode terminal of the reverse rectifier diode D, is a two-terminal smoothing circuit-R ,) Is connected to the anti-ground terminal S,

 The ground-side terminal of the two-terminal smoothing circuit (C ^ R.) Is connected to the positive terminal of the DC power supply Vcc, and the negative terminal of the power supply Vcc is connected to ground.

Anti ground terminal s of the two terminals smoothing circuit (C, · R 1), the output terminals u, through, is connected to the inverting input terminal (I) of the comparator 6 _5, wherein the comparison voltage generator 6 ₆ the content, the input terminal I, the output terminal u _2, and graph down mode pin, and forward rectifying diode D ₂ in series branches, and two terminals smoothing circuit of the parallel branch the (C ₂ · VR ₂₎ And

The two-terminal smoothing circuit (C ₂ · VR ₂ ) consists of a parallel connection circuit of a smoothing capacitor C ₂ and a resistive voltage divider VR ₂ with a sliding terminal.

Input terminal I is connected to the anode terminal of the forward rectifier diode D _2, the cathode terminal of the forward rectifier diode D ₂ is 2 terminals smoothing circuit counter ground terminal s of the (C ₂ · ν R ₂₎ Connected to ₂ ,

The ground terminal of the 2-terminal smoothing circuit (C ₂ · VR ₂ ) is connected to ground,

The sliding terminal of the resistive voltage divider VR ₂ is connected to the non-inverting input terminal (+) of the comparator 65 via an output terminal u ₂ .

 Things.

 The third embodiment of the target detecting apparatus using speckle pattern light of the invention of this application is as follows.

 In the first or second mode of the target detection device using the speckle pattern light,

High-voltage side terminal of the second sliding terminal resistor-divider VR _3, and a second comparator 6 ₅₂ containing second sliding terminal resistor-divider VR ₃ is slip of the resistor divider VR ₂ Connected to the terminal, Inverting input terminal of the comparator 6 ₅ (-), said reproduction DC signal voltage V, is applied, its non-inverting input terminal (+) of the first sliding terminal of the resistor divider VR ₂ Output voltage α'V2 is applied,

Inverting input terminal of the second comparator 6 _S2 (-), said reproduction DC signal voltage is applied, its non-inverting input terminal (+), the output of the second sliding terminal of the resistor divider VR ₃ Voltage / 3 · α '· V 2 is applied,

The comparator 6 _s output 1 on the output side of the (X,) is given, the output of the second comparator 6 ₅₂ Output 2 (X ₂₎ is given,

 Things.

 A fourth embodiment of the target detecting apparatus using the speckle pattern light of the invention of the present application is the third embodiment of the target detecting apparatus using the speckle pattern light.

A first combinational logic circuit, a second combinational logic circuit L ₂ , and a third combinational logic circuit L ₃ ,

X> common first input thereto, when the second input and chi _2, its these logic output A, B, and C, respectively,

 A-1 · X 2,

 B = X 1 ·, X 2,

 G =, X 1 ·, X 2,

 However, one is given by a negation sign (reversal sign), · is an AND sign,

 Things.

Wherein the target detection apparatus according to the speckle pattern light is disposed a light-receiving optical system 6 i in front of the photoelectric converter 6 _2,

Receiving optical system 6, is any reflected light including speckle pattern light 4 coming from the monitored space, focused on the photoelectric converter 6 ₂ of the light-receiving surface, You can do this.

 In the target detection device using each speckle pattern light, the light emitter 5 and the light receiver 6 are arranged in parallel and integrated, thereby forming the light emitter / receiver 5.6.

 You can do this.

 An edge position detection system for a transparent sheet according to the invention of the present application comprises: a target detection device using the speckle pattern light of the fourth embodiment; and a reflector 9;

The target object detection device, can the edge E of one of the transparent sheet 1 ₂ long (time) is traveling on the predetermined lateral line of a given travel path, the beam-like co heat - les The light 2 is arranged at a position where the edge E is illuminated obliquely,

 The reflector 9 is located on the extension of the beam-shaped coherent light 2 and is also located at a position beyond the edge E,

Without edge E force horizontal shake (shake) and come to be on a predetermined side line of a given travel path, only the product second output of the combinational logic circuit L ₂ of the target detection device (B) is a logical 1

When the edge E swings inward, only the output (A) of the _third combinational logic circuit L3 becomes logic 1, and

 When the edge E swings outward, only the output (C) of the first combinational logic circuit L, becomes logic 1,

 This is what we did. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is an external view of a target detecting device according to a first embodiment of the present invention.

Figure 2 shows the laser beam projected at right angles to the transparent plastic plate. It is explanatory drawing of a transmission and reflection phenomenon.

 FIG. 3 is an explanatory diagram of a speckle pattern.

 FIG. 4 is a block diagram of a light emitting and receiving device which is a main part of the first embodiment of the target detecting device.

 FIG. 5 is a connection diagram of a DC regenerator and an automatic tracking comparison voltage generator, which are main parts of a second embodiment of the target detection device.

 FIG. 6 is a schematic diagram of input / output waveforms of the DC regenerator and the automatic tracking type comparison voltage generator.

 FIG. 7 is a connection diagram of two resistive voltage dividers and two comparators, which are main parts of the third embodiment of the target detecting device.

 FIG. 8 is a schematic diagram of input and output waveforms of the two comparators.

 FIG. 9 is a block diagram of three combinational logic circuits which constitute a main part of the fourth embodiment of the target detecting device.

 FIG. 10 is an explanatory diagram of a three-level detection system.

 FIG. 11 is an explanatory diagram of a boundary detection system.

 FIG. 12 is an explanatory diagram of a transparent sheet edge position detecting system according to the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

 [First embodiment of target detection device]

 A first embodiment of a target detecting apparatus using speckle pattern light according to the invention of this application will be described.

 (Appearance)

 FIG. 1 is a side view of the first embodiment.

In FIG. Is the light exit, 6 is the receiver, 6 Is a light receiving unit inlet, 7 is an output signal, and 8 is a DC power supply. In addition, 1 is a target, 2 is a coherent light (for example, a semiconductor laser light) in an extremely fine beam shape, 3 is specular reflection light, and 4 is a speckle pattern light. The coherent light 2 is preferably visible light.

 The light-emitter 5 and the light-receiver 6 are arranged in parallel as shown in the figure and integrated to form the light-emitter and light-receiver 5. This makes handling easier. However, in some cases, the emitter 5 and the receiver 6 can be separated from each other and configured separately.

 In FIG. 1, the emitters and receivers 5 and 6 and the target 1 are drawn as if they are close to each other due to the paper width. In reality, however, they can be greatly separated from each other.

 In this embodiment, the DC power supply 8 is configured separately outside the light emitting and receiving devices 5 and 6. Its voltage is about 5 volts.

 The coherent light 2 in the form of a fine beam is projected toward the monitored space. The space to be monitored (not shown) has the same shape and the same size as the beam-shaped coherent light 2 or is slightly larger.

 Floodlight exit 5. When the target 1 does not exist in the monitored space, the coherent light 2 in the form of a very fine beam emitted from the target passes through the space as it is and ends up there, but when the target 1 exists in the same space Are scattered and reflected on the surface, and generate speckle pattern light 4 in all directions, and a part of the light 4 enters the light receiving unit entrance 6. To come.

 (Explanation of terms)

 Here, some terms used in this specification are explained.

"Target" refers to a physical target. In the specification of this application, the extension of a target is to be understood in a broad sense: transparent objects (for example, transparent glass or fresh water), black objects (for example, carbon black), extra-fine objects (for example, fiber or hair), and so on. This includes the boundaries between light and dark areas on the surface of the object, the edges of transparent or black sheets, as well as water vapor, fog and smoke.

 “Specular reflection” is synonymous with “specular reflection” and refers to reflection when the size of the unevenness of the reflecting surface is much smaller than the wavelength of the incident wave. In specular reflection, the direction of the reflected wave is within the plane of incidence (the plane that includes the direction of the incident wave and the normal to the boundary surface), and the angle of incidence and the angle of reflection are equal. (See page 106, right column).

 “Diffuse reflection” refers to reflection when the unevenness of the reflection surface is about the same as or larger than the wavelength. Therefore, in diffused reflection, the reflected wave travels in various directions. (See the same column on the same page of the RIKEN Dictionary).

 “Transmitted light” refers to light transmitted through a material layer or interface.

 The “speckle pattern” is a pattern of bright and dark spots generated when coherent light is scattered by fine irregularities on a rough surface and interferes with each other in an irregular phase relationship. The shape and size of each spot depends on the shape and size of the aperture of the optical system that forms the speckle pattern, and the smaller the aperture, the larger the spot. (Refer to the above-mentioned RIKEN Dictionary, p. 667, left column).

 Figure 3 is a schematic diagram of the speckle pattern. In Fig. 3, 4 'is a speckle pattern, and each 4' is a bright spot (bright spot) that constitutes the same pattern.

).

 “Speckle pattern light” refers to reflected light that produces a speckle pattern. FIG. 2 is an explanatory diagram of the transmission and reflection phenomena of laser light projected at right angles to a transparent plastic plate. In FIG. 2, 1 is a transparent plastic plate (material layer), 2 is a beam-shaped coherent projection light, and 3 'is a transmitted laser light. Reference numeral 3 denotes a weak reflected light, and reference numeral 4 denotes a weaker pattern light.

There are individual differences in the wavelength range of visible light, and the lower limit is 360 to 400 nm (nanometer), the upper limit is about 760 to 830 nm. (Refer to the above-mentioned RIKEN Dictionary, p. 229, right).

 (Emitter / receiver)

 FIG. 4 is an explanatory diagram of an internal configuration of a light emitting and receiving device which is a main part of the first embodiment of the target detecting device.

In FIG. 4, reference numeral 5 denotes a projector; The light projecting unit outlet 5, the projection optical system, 5 ₂ co Heeren DOO light source (e.g. laser diode), 53 an automatic power control circuit (APC circuit) 5 ₄ is an oscillator.

6 is a light receiver; Receiving unit inlet is 6, the light-receiving optical system, 6 ₂ photoelectric converter (e.g. E Bok diode) 6 ₃ logarithmic amplifier, 6 ₄ DC regenerator 6 ₅ comparator 6 ₆ compares voltage A generator, a reference power supply in this embodiment, and 7 is an output signal.

 8 is a DC power supply, and 0 is an output terminal. The power supply circuit is not shown.

The light projecting optical system 5 is composed of a condenser lens (or collimating lens). The laser diode 5 _2, in this embodiment, approximately 1 m W (Class 2

) Coherent visible light 2 is emitted. It also has a built-in photodiode (not shown) for monitoring optical power temperature changes.

Automatic power control circuit 5 _3, and take advantage of the monitoring output of the mined diode, laser diode 5 ₂ optical power that controls the power sale by a constant value.

Oscillator 5 ₄ an optical output of the laser die Hauts de 5 ₂ on 'off for modulating, generates a low-frequency modulation signal. The low frequency modulation signal frequency is preferably about 5 kHz. The low-frequency modulation signal, a laser diode 5 Track la Njisuta to chiyo Tsu path circuit is inserted in the _second power supply circuit (no shown) to control the on and off. The role of the light-receiving optical system 6, is in the this focusing the speckle pattern light received, to be Dakeho Bok diode 6 ₂ of the light-receiving surface. The light receiving optical system 6, can be omitted in some cases. In that case, the detectable distance must be slightly shorter, but the cost is slightly reduced.

 An optical filter (not shown) for absorbing light (disturbance light) other than laser light can be inserted before or after the light receiving optical system 6. This optical filter can be integrated with the light receiving optical system 6.

The main role of mined die Hauts de 6 _2, weak speckle pattern light 4 is in electrical signal in the photoelectric conversion child. However, even for strong specular light, stable photoelectric conversion must be possible.

Logarithmic amplifier 6 _3, for example, a series resistor to the non-inverting input terminal of the operational amplifier, and by the child connected the diode element having an exponential characteristic to the feedback circuit, it is realized. (Refer to “Electrical Engineering Handbook New Edition”, pp. 431-1432, published by Ohmsha on February 28, 1988).

And with the die Hauts de element must what index characteristics which extends up to substantially the origin (e.g., on a data table until ^{I. = 1 0- 5 A =} 1 0 microamperes position) to select . Such an exponential characteristic is currently realized by a kind of shot diode and is commercially available.

 A photodiode used in combination with such a diode element must have a particularly low dark current.

 As an operational amplifier, a CMOS inverter can be used to achieve higher speed and lower power consumption.

The role of the logarithmic amplifier 6 _3, can the amplitude of the input signal is small is to strongly stretched增幅, come to the amplitude of the signal becomes large, the Ru child Nea compression amplification.

The subsequent stage of the logarithmic amplifier 6 _3, for example, the three-stage linear amplifier (no shown) Connected. A small input signal (for example, a signal of about 10 μA) is maximally amplified by both amplifiers, and its output reaches, for example, over 2 volts. The largest input signal is compressed and amplified, but its output is stopped at a voltage just before saturation, for example, about 4 volts.

If an AC component derived from ambient light (for example, 100 Hz noise derived from a fluorescent lamp) is present in the analog voltage (current) after photoelectric conversion, low-frequency rejection is required to block the AC component. filter or band stop filter (for example Roh Tchifu I filter), downstream of the logarithmic amplifier 6 _3, desired to introduce arbitrary.

DC regenerator 6 _4, in this embodiment, owed consist a DC blocking filter and a rectifying smoothing circuit, superimposed DC component (noise) completely blocked, only the modulation frequency component (signal) Rectified and smoothed to obtain a reproduced DC signal. Therefore, the obtained reproduced DC signal is proportional to only the intensity of the incoming reflected light (for example, the scattering pattern light 4).

Comparator 6 _5, the inverting input terminal (-) voltage applied reproduced DC signal is, when exceeded the reference voltage applied to the non-inverting input terminal (+), low (Low) level (or high ( High) level) output signal.

 When the target 1 does not exist in the monitored space, the coherent light 2 projected from the light-projecting optical system 5, passes through the same space, but ends up in the same space. When the target 1 exists in the target, as shown in FIG. 4, the target is scattered and reflected on the surface to generate speckle pattern light 4 in all directions, and a part of the light returns to the light receiving optical system 6.

 (How to install floodlight 5)

 The projector 5 is installed in the following manner.

 (1) Temporarily fix the projector 5 toward a desired space to be monitored.

(2) Install a light-absorbing shielding plate (not shown) at a position beyond the monitoring target space. You. As a result, it is possible to prevent the generation of reflected light (noise) due to the non-detection target object on the extension of the monitoring target space. In addition, there is no possibility that human eyes are damaged by the coherent light 2 in the form of a very fine beam that has passed through the monitoring target space.

 (3) Turn on the power switch and connect the DC power supply 8 to the emitter 5. Ultrafine beam-shaped coherent visible light 2 is emitted from the projector 5 toward a desired space to be monitored.

 (4) By inserting the simulated target in the desired monitoring target space and visually recognizing the position of the minute visible light spot on the simulated target, the coherent visible light 2 in the form of a very fine beam is generated. Check to see if you are out of the desired monitored space.

 (5) When the coherent visible light 2 in the form of a very fine beam deviates from the desired monitoring target space, the attitude of the projector 5 is corrected, and the beam-like visible light deviates from the monitoring target space. No.

 (6) The simulated target is inserted into and removed from the monitored space, and at the time of insertion, the distance to the reflection surface and the inclination of the reflection surface (that is, the angle between the normal of the target surface and the beam-shaped coherent light). Are varied and the presence or absence of the detection signal 7 by the light receiver 6 is checked to confirm that the target can be detected.

 (7) Fix the projector 5 in the same position and posture.

 (Operation of the first embodiment)

 The operation of the target detecting device according to the first embodiment will be described.

 When the power switches of the emitters and receivers 5 and 6 are turned on, the coherent visible light 2 in the form of an ultra-fine beam with amplitude modulation is emitted from the emitter 5 toward the space to be monitored.

When target 1 does not exist in the monitored space, a coherent The visible light 2 passes through the space and is absorbed by, for example, a light absorbing shielding plate (not shown). No reflected light arrives.

 When the target 1 exists in the monitoring target space, the ultrafine beam-shaped coherent light 2 irradiates the minimum spot on the surface of the target.

 Then, as shown in FIG. 1, FIG. 2, or FIG. 4, the specular reflected light 3 is generated in a specific direction, and the scattering pattern light 4 is generated in all directions, as shown in FIG. 1, FIG. 2 or FIG.

 The reflected light becomes stronger when the distance from the projector 5 to the surface of the target 1 decreases, and becomes weaker when the distance increases.

 The reflected light is also stronger when the light reflectance of the target surface is higher, and weaker when the light reflectance is lower.

 The specularly reflected light 3 has zero light (see Fig. 1 or Fig. 4) returning to the original direction (toward the light receiver 6) when the inclination of the target surface is slightly increased. In the case of the circle pattern light 4, even if the inclination of the target surface is further enlarged, the light returning in the original direction (the direction of the light receiver 6) does not become completely zero.

In short, the specularly reflected light 3 returning to the photoelectric converter 6 ₂ in the light emitting and receiving devices 5 and 6 has a short distance from the light emitting and receiving devices 5 and 6 to the target 1, and the light on the target surface It is strongest when the reflectance is high and the inclination of the target surface is zero, but it becomes zero when the inclination is slightly increased.

However, specs Rupata emission light 4 returning to the photoelectric converter 6 ₂ of the emitter and receiver 5, 6 has a long distance from the emitter and receiver 5.6 to the target 1, the light reflectance of the target surface Even when the target surface is low and the inclination of the target surface becomes large, it does not become completely zero.

 The invention of this application actively utilizes such a phenomenon.

When target 1 enters or exists in the monitored space, the emitter / receiver (5 * 6 ) Receiver entrance 6). And the light receiving optical system 6, via a photoelectric converter 6 _2, the reflected light arrives. The incoming reflected light is specularly reflected light 3 when the inclination of the target surface is zero, and speckle pattern light 4 when the inclination is large.

The photoelectric converter 6 ₂ is often, although than that will invade natural light or ambient light to disturbance light such as illumination light also simultaneously, their environmental light or disturbance light, superimposed on a desired reflected light It becomes extremely loud noise.

Specularly reflected light 3 or speckle pattern light 4 arriving on the photoelectric converter 6 _2, by the converter 6 _2, it is converted into an electrical analog signal.

 When the converted electric analog signal has a small amplitude, the logarithmic amplifier 6 strongly expands and amplifies the converted signal.

 Therefore, the weak speckle pattern light 4 when the inclination of the target surface is large as shown in FIG. 4 or the weak specular light 3 arriving from the transparent object 1 as shown in FIG. Even if it is strong specular reflection light coming from the mirror surface, it can be detected stably without saturation.

 The modulation frequency component in the logarithmically amplified electric analog signal is filtered and smoothed by the DC regenerator 6-to be a regenerative DC signal. However, the DC component (noise) derived from ambient light or disturbance light in the electric analog signal is completely blocked and is not reproduced.

The non-inverting input terminal of the comparator 6 ₅ (+) is always from the reference power source 6 ₆ standards voltage is applied.

Play DC signal voltage outputted from the DC regenerator 6 ₄ is applied to the inverted input terminal of the comparator 6 ₅ (1). The can and its reproduction DC signal voltage exceeds the reference voltage, inverts the output voltage of the comparator 6 _5, and the detection signal 7 of the target 1. The detection signal 7 is given to a display device, a sound notification device, and / or a memory.

 [Second embodiment of target detection device]

 A second embodiment of the target detecting device of the invention of this application will be described in detail.

 (Configuration of Second Embodiment)

 FIG. 5 is a connection diagram of a DC regenerator, an auto-following comparative voltage generator, and the like according to the second embodiment of the target detection device.

5, the last stage of 6 A is a linear amplifier, 6 ₄ DC regenerator 6 ₆ automatic tracking type comparison voltage generator, a common input terminal I for both 6 ₅ comparator, T _r is the output It is a transistor.

DC regenerator 6 ₄ consists縱続connection circuit of a single reverse rectifier circuit (D,) and one of the smoothing circuit (C, · R,) and.

The reverse rectifier circuit (D,) consists of only one series branch, which consists of only the rectifier diode D, inserted in the negative direction. Rectifier die Hauts de D, the forward threshold voltage V _F of the manufactured silicon, about 0.6 volt Bok a is (ninth to fourth 3 page 2 under the left column supra "Electrical Engineering Han Dobu'click" 8 Line)

 The smoothing circuit (C, R) consists of only one parallel branch, and the parallel branch consists of a parallel connection of a capacitor C and a resistor.

The cathode of the rectifier diode is connected to the common input terminal I, and the anode is connected to the anti-ground terminal s, of the smoothing circuit (C, R,), and the smoothing circuit (C, R,) Is connected to a ground (not shown) via a DC power supply Vcc, and the anti-ground side terminal s, of the smoothing circuit (C, R,) is further connected to a DC regeneration circuit as shown in the figure. vessel 6 ₄ output terminals (u,) to Ru is connected. The voltage of the DC power supply Vcc is about 5 volts in this embodiment. Automatic tracking type comparison voltage generator 6 ₆ also, one of the forward rectifier and (D ₂₎

, And a cascade connection circuit with one smoothing circuit (C ₂ · VR ₂ ).

The forward rectifier circuit (D ₂ ) consists of only one series branch, the series branch consisting only of the rectifier diode D ₂ inserted in the positive direction. Forward Direction rectifying diode D, also the forward rise voltage V _F of Ru about 0.6 Bol Bok der.

The smoothing circuit (C ₂ · VR ₂ ) consists of only one parallel branch, and the parallel branch consists of a parallel connection of a capacitor C ₂ and a resistive voltage divider with a sliding terminal VR ₂ .

The anode of the rectifying diode D ₂ is connected to the common input terminal I, the cathode is connected to the counter-Grad down de terminal s ₂ of the smoothing circuit (C ₂ · VR _2), the smoothing circuit (C ₂ · VR ₂ Gras emissions de terminal of) is connected to the ground, sliding terminal of the resistor divider VR ₂ is connected to the output terminal U 2 of the automatic tracking type comparison voltage generator 6 _6. The domain of the partial pressure ratio α due to the manual adjustment of the sliding terminal is 1 ≥ α >> 0.

Total resistance value between the fixed terminals of the resistor divider VR _2, for convenience of explanation, the resistance R, resistance value and the same level. That is, VR ₂ = R 2.

 The rest of the configuration of the target detecting device according to the second embodiment is the same as that of the first embodiment.

 (Operation of the Second Embodiment)

When the power sweep rate Tsu add switch (no shown), and our circuit shown in immediately steady state, the DC power supply V cc, resistor, rectifier diode, rectifier die Hauts de D _2, and resistor divider VR ₂ ( = R,), a steady current i _s flows to ground.

is = (V cc-VFX 2) / (R, + VR ₂ ) = (VCC - VFX 2) / 2 R, (1) stationary potential v _s at the connection point between the rectifier die Hauts de and D ₂ is graphene emissions de - DC power supply V cc- resistor R »one rectifying diode D, Calculating with the route of

V _s = V cc-is-R 1-VF (2) Ground resistance VR ₂ — Calculating with the route of rectifier diode D ₂ , v _s = is · VR ₂ + V r (3) is there. If Equations 2 and 3 are added to each other, is and V _F cancel, and

2 V s = V cc (4) Therefore, v _s = V cc Z 2 (5).

The potential V of the output terminal of the DC regenerator 6 _4, i.e. the potential V i of the inverting input terminal of comparator 6 ₅ (1) is

 V, = (V c c / 2) + V F 2.5 .5 + 0.6 (V)

 = 3.1 (V) (6).

Further, the voltage dividing ratio alpha, as described above, 1 ≥ alpha >> from 0, the non-inverting input terminal of the automatic follow-up form comparisons voltage generator 6 ₆ potential [nu ₂ of the output terminals, i.e. comparator 6 ₅ ( +) Potential V ₂ is

 V 2 = (V c c / 2-V F) X α

 = (2.5-0.6) X α

= 1. 9 x α (V ) (7) and Do Ri, [nu, a "[nu _2. This relationship is shown at the left end of Fig. 6 (a). This and come, the output potential of the comparator 6 ₅ Ri Do a b c level, deca preparative La Nji Star T _r is turned off. This operation is shown at the left end of Fig. 6 (b).

Fig. 6 (a) shows a DC regenerator according to the second embodiment of the target detection device. And schematic diagram of input and output waveforms of the automatic tracking type comparison voltage generator, FIG. (B) is an explanatory view of the on-off state of the output transistor T _r in the embodiment.

 Next, when the modulation frequency component (low frequency component) arrives at the common input terminal I from the final stage 6 A of the linear amplifier, the potential V force at the same point I is substantially equal to the voltage curve V in FIG. 6 (a). Start sinusoidal fluctuation.

The voltage curve V may even s (happens) begins from the positive half cycle Runode, first, the comparison voltage generating circuit 6 ₆ starts rectification smoothing operation.

In each positive half cycle, the input potential V of the common input terminal I increases more than the steady potential v _s (a half of V cc), as shown by the voltage curve V in FIG. to, with the conduction of the rectifier diode is blocked, the common input from terminal I, the rectifying diode D ₂ - by reason through a smoothing circuit (C ₂ · VR _2), the big pulsating Ri by constant current i _s The current i + force is directed to ground.

As a result, the positive charging voltage (v ₂ / a) of the capacitor C ₂ of the smoothing circuit (C ₂ · VR ₂ ) is proportional to the voltage curve v ₂ of FIG. 6 (a). And it increases step by step. Therefore, the output potential of the sliding pin, that is, the output potential of the comparator electrostatic pressure generating circuit 6 _6, as the curve v _2, for each cycle, and stepwise increases.

Then, when the negative half cycle is reached, the DC reproduction circuit 6 ₄ also starts rectification flat smooth operation.

That is, in each negative half cycle, the input potential V of the common input terminal I is lower than the steady potential v _s (half of V cc), as shown by the voltage curve V in FIG. 6 (a). to rectifying the conduction of diode D ₂ is blocked by the co, from the DC power supply V cc, the smoothing circuit (C> - R,) via an rectifying diode D _i, the steady-state current i _s Larger pulsating current i-force Flows toward force terminal I. As a result, (the absolute value IV _{C 1} I) of the DC charging voltage Va of the capacitor C, increases step by step in each cycle.

At this time, the output potential V of the DC reproduction circuit 6 _4, is Ru is given by the following equation.

. v = V cc - | as the chitin from V ol (8) Equation 8, the output potential V of the DC reproduction circuit 6 _4, is, as the voltage curve V, in FIG. 6 (a), the per cycle And gradually decrease.

In short the above, can the modulation frequency component (signal component) has brought arrives to the common input terminal I, the DC output potential v ₂ of the comparison voltage generating circuit 6 _6, as the voltage curve v ₂ shown in FIG. 6 (a) for each cycle, and stepwise increased, on the contrary, the DC reproduction circuit 6 ₄ DC output voltage V, but as the voltage curve v> of FIG (a), for each cycle, and decreases in stages I do.

The input potential V of the inverting input terminal of the comparator 6 ₅ (1), and, the magnitude relation between the input voltage V ₂ of the non-inverting input terminal (+) is finally, V,> from V _2, V, <V It flips to ₂ .

As a result, the output potential of the comparator 6 ₅ is inverted from low level to high level inverted from the off state as the output transistor T _r force diagram 6 (b) and to the on state.

This Kodewa, the ON state of the output transistor T _r, the detection signal of the target 1.

However, when even Ri by a threshold (determination level) V _t with amplitude V of the incoming the modulated component becomes small, magnitude relation of V, and v ₂ is not inverted, therefore, the detection signal is not issued. Threshold V _t (determination level) is adjusted by adjusting the division ratio of the resistor divider VR _2.

In the following, the incoming the modulated component amplitude V power threshold V _t (determination Les DOO-out is less than Bell),-out bets dark level, less than the threshold value V _t will leave a light level.

After that, when the target 1 leaves the monitored space, the magnitude relationship between V and V ₂ reverses again to V>> V 2 as shown in Fig. 6 (a), and the output of the comparator 6 _s potential is reversed back to the low level, the output transistor T _r is inverted back to oFF state.

 As described above, according to the second embodiment of the target detection device, it is possible to reliably detect that a bright-level modulation frequency component has arrived at the common input terminal I.

 Therefore, it can be reliably detected that the target 1 has entered or existed in the monitored space.

Furthermore, according to this embodiment, the common input even if with any DC voltage (i.e., noise) arrives to the terminal I, the output potential V of the DC regenerator 6 _4, an automatic tracking type comparison voltage generator 6 _B the magnitude relationship between the output potential v ₂ of the not inverted, therefore, the output voltage of the comparator 6 ₅ is in any way not reversed.

That is, the DC potential V of the common input terminal I is, even as it becomes the same level if V cc (5 volts), the output voltage V 2 of the automatic tracking type comparison voltage generator 6 ₆ at most, V cc _{- V F = 5 -..} 0 6 = 4 although 4 of not only reach the bolt, this time already, the output potential V of the DC regenerator 6 _4, is because has reached the same level as V cc , V i> V 2, are still invariant.

Maintaining Conversely, even if the DC potential V of the common input terminal I has dropped to if zero volts, the output voltage V of the DC regenerator 6 _4, is at least V _F value (0.6 Bo Le Bok) by that it is a force ^s to, this time already, the output potential v ₂ of the automatic follow-up form comparisons voltage generator 6 ₆ because they reached zero volts, _{V l>} V ₂ becomes relationship and still Is immutable. Therefore, if the DC component from the ambient light to disturbance light (noise) can be to have reached the common input terminal I, the output potential of the comparator 6 ₅ never not inverted, the output preparative La Njisuta T _r Does not reverse to the on state.

 This is a great advantage of this embodiment.

 Other operational effects of the second embodiment are approximately as follows.

(1) According to this embodiment, both the maximum detectable distance and the detectable distance range are greatly expanded. For example, 2 to 45 cm for black carbon paper, 2 to 70 cm for black rubber, 2 to 100 cm for black alumite, 2 to 100 cm for brown corrugated paper, white copy. For paper, it was 2 to 120 cm, and for transparent plastic with a transmittance of 91%, it was 2 to 260 cm. However, the ambient illuminance is 300 lux (2 m under a 20 W fluorescent lamp), and the inclination of the target surface is within 10 degrees.

(2) Since the light emitted from the laser diode 5 ₂ are co Heeren DOO, projection optical system 5, by, can and this narrow beam Wes preparative Kai a rather very small, therefore the child achieve high resolution Can be done.

 For example, a hair of 50 mφ can be easily detected from a place about 15 cm away.

 In addition, a cable core of about 100 wm Φ can be easily detected from a place as far as 70 cm away.

 Alternatively, a tin-plated wire of about 0.1 mm <) Xl.5 mm can be easily detected from a place 50 cm away.

 (3) Even if the inclination of the target surface with respect to the beam-shaped coherent light 2 becomes extremely large, the target can be detected.

 For example, even when white copy paper distant from 60 cm (or 40 cm) is inclined by 70 degrees (or 80 degrees), it can be reliably detected.

Black carbon paper 20 cm (~ 15 cm) away from 65 degrees (~ 80 degrees) ) Even if it is tilted, it can be detected reliably.

 (4) Smoke in a colorless transparent or brown translucent bottle or cylinder can be detected. The beam-shaped coherent light for this purpose must be applied obliquely to the surface of the colorless transparent or brown translucent bottle or cylinder. (At right angles, it is difficult to detect.)

 (5) Water in colorless and transparent bottles or cylinders can also be detected. The beam-shaped coherent light for this purpose is applied obliquely to the surface of the colorless and transparent bottle or cylinder, and transmitted through a reflecting plate (for example, white paper) for reflecting transmitted light in the opposite direction. Must be placed on the side. In the absence of water, the refractive index changes, so transmitted light may or may not come back.

(6) because using the laser diode 5 ₂ which emits visible light (red light) can be easily visually recognize the irradiation spot Bok. Therefore, the work of mounting the light emitting and receiving devices 5 and 6 becomes easy.

(7) blocking the signal light emitted from the laser diode 5 _2, since the intermittent modulated by oscillator 5 ₄ output frequency (e.g. Ruth to 5 miles), natural light or illumination Mitsuyoshi come current component (i.e., DC component) However, it became extremely easy to extract the current component (AC component) derived from the signal light.

(8) to e Todaio de 6 ₂ photodetectors 6, using a dark current that minimal, the non-linear diode of the logarithmic amplifier 6 _3, because I used as the forward index characteristics extends to near the origin However, dynamic cleanliness has been greatly expanded. That is,

When very weak Supe' Kurupata emission light 4 is reached, when the photoelectric conversion by the host Todaio de 6 _2, but inevitably the times 1 0 microamperes following very weak current, still the logarithmic amplifier 6 ₃ , the output is amplified to about 2 volts. You can go up

Strong when the positive reflected light 3 has come, and the compression增幅by the logarithmic amplifier 6 _3, saturation of the voltage immediately before the final stage amplifier the output voltage, for example, 4 stop the degree of Bol Bok excess (and etc. ) The sensitivity adjustment during this time

, No need at all.

 (9) Therefore, the DC power supply 8 was able to achieve lower voltage and lower current consumption. In fact, we were able to achieve 5 volts (4, 5-6, 5 volts) and 40 milliamps or less.

(1 0) from the automatic tracking type the comparison voltage generator 6 ₆ has enabled the completely prevents child DC components from natural light or illumination light.

 (11) Since the AGC circuit is not required for the receiver 6, instantaneous detection of the target 1 is possible.

 (12) The dynamic range has been greatly expanded, eliminating the need for selecting and liking target targets.

 [Third Embodiment of Target Detector]

 A third embodiment of the target detecting device of the invention of this application will be described in detail.

 (Constitution)

 FIG. 7 is a connection diagram of two resistance voltage dividers and two comparators, which are main parts of the third embodiment.

In FIG. 7, u, output terminals u, identical, u ₂ is the output terminal u ₂ the same, VR 2 of the comparison voltage generator 6 ₆ automatic follow-up type of drawing of the DC regenerator 6 ₄ 5 smooth Same as the resistor divider VR _{2 in the} circuit (C ₂ · VR ₂ ), _{S l} , s

2 is the same as the anti-ground terminal S i, S 2 of the smoothing circuit (C 2 · V R 2).

Then, VR ₃ and the second sliding pin resistor-divider, 6 ₅₁ first comparator (In fact the same as the comparator 6 ₅ in the second embodiment), 6 ₅₂ second comparator, the T _{gamma 1} first output bets la Njisuta, T _r2 second output preparative La Njisuta, 0 > the first output terminal, the 0 ₂ second output terminals, X, the first logic output, X 2 is a second logical output.

A first output terminal 0, and the second to the output terminal 0 _2, if necessary, (see FIG. 9) set combined logic circuit is connected added. (More on that later).

The third embodiment differs from the above second embodiment, a second resistor divider VR _3, the second comparator 6 _52, a first output transistor T _rl, the 2 and an output transistor _Tr2 . The Chinami, the first comparator 6 ₅₁ is the same as the only comparator 65 in the second embodiment.

The second high-voltage terminal of the resistor divider VR ₃ (anti Grad down de side terminal) is connected before Symbol sliding terminal of the resistor divider VR _2, the inverting input terminal of the second comparator 6 ₅₂ ( I) is connected in parallel to the inverting input terminal of the first comparator 6 ₅₁ (1), the non-inverting input terminal (+) is connected to the second sliding terminal of the resistor divider VR _3, the output terminal of the second comparator 6 ₅₂ is connected to the base of the second deca transistors T _r2.

Assuming that the voltage dividing ratio of the second resistor voltage divider VR ₃ itself is 13, the domain of 13 must be 1 ≥) 3 >> 0.

It should be noted, first, second output door La Njisuta T _r ,, T _{r 2} is, in some cases it is and this will be omitted.

 The remaining configuration of the target detecting device according to the third embodiment is the same as that of the second embodiment.

 (motion)

FIG. 8A shows the first and second comparators in the third embodiment. 65 is a schematic diagram of input and output waveforms of 65 and 652. FIG.

In FIG. 8 (a), V is the input potential of the common input terminal I (see FIG. 5) of the preceding stage of the DC regenerator 6 ₄ and the automatic tracking type comparison voltage generator 6 _6, V, the first and second input potential of each inverting input terminal of the second comparator 6 ₅₁ and 6 _S2 (one), V 2 is input potential of the non-inverting input terminal of the first comparator 6 ₅₁ (+), v ₃ is the second Input potential (=) 3 ν ₂ <of the non-inverting input terminal (+) of the comparator 6 ₅₂

V 2)

FIG. 8 (b), in the same third embodiment, the first and second output Bok La Njisu evening T _gamma, and is an explanatory view of T _{gamma 2} on-off state.

8 (b), the output 1 and the first output preparative La Njisuta T _{rl 2} on-off state, and the output 2, the second on-off state of the output tiger Njisuta Ding _{gamma 2.}

The modulation frequency component (signal) is applied to the common input terminal I. In, is reached, it begins rectification smoothing operation of the DC regenerator 6 ₄ and the automatic tracking type comparison voltage generator 6 6 as described above.

Then, the output voltage V of the DC regenerator 6 _4, but decreased for each negative half cycle, the output voltage [nu ₂ of the automatic tracking type comparison voltage generator 6 ₆ is increased for each positive half cycle. At the same time, the output voltage [nu ₃ of the second resistor divider VR ₃ (= beta

V 2 <V 2) also increases in proportion to this every positive half cycle.

As a result, the magnitude relation between V \ and [nu _2, at time, V from _{V l>} V _2, inverted to <V _2, I it connexion, the output voltage of the first comparator 6 _51, the low-level Then, the first output transistor _Tr , inverts from the off state to the on state. However, this does not apply when the amplitude of the incoming modulated component (signal) is smaller than the first threshold value (first determination level) _Vtl . The first threshold value (first determination level) V _t, is a function of the partial pressure ratio α only the first resistor divider VR _2. Next, the magnitude relationship between V, and V ₃ (= β V 2) is also determined at time t ₂ (t ₂ > t

,), V,> V, V! <V

The output voltage of the second comparator 6 ₅₂ inverts from low level to high level, the second output transistor T _r2 is also reversed from the OFF state to the ON state. However, the amplitude a second threshold value (second determination level) of the arriving the modulated component (signal) V _t2 (> V _t.) Good Ri when it becomes small this shall not apply. A second threshold value (second determination level) V _t2 is a function of the partial pressure ratio 3 of the first voltage division ratio of the resistor divider VR ₂ alpha and a second resistive divider VR _3.

According to the third embodiment, the modulated light that arrives at the photoelectric converter 6 ₂ in FIG. 4 (reflected signal light) intensity, thus also arriving at the input terminal I of the DC regenerator 6 ₄ 5 The magnitude V of the modulated frequency component (signal voltage) is divided into three levels. That is, a “dark level” that is less than the first threshold (first determination level) _Vtl, and a “gray” that is _{equal to} or more than the first threshold _{Vtl and} less than the second threshold _Vt2 (second determination level). level ", and" bright level "of the second threshold value V ₁₂ or more, a two.

 (1) Therefore, according to this embodiment, it is possible to detect an intermediate color (ash level) of a printed material or the like.

 (2) The boundary between the dark level and the light level on the object surface can be detected. At this time, the boundary between the dark level and the light level is detected as the gray level.

 (3) The meandering of the edge of the transparent sheet can be detected.

 [Fourth embodiment of target detection device]

 A fourth embodiment of the target detecting device of the invention of this application will be described in detail.

 (Constitution)

FIG. 9 shows each of the three combinational logic circuits forming the main part of the fourth embodiment. It is a block diagram.

In Figure 9, L, the first combination logic circuit, L ₂ is the second combination logical circuit, L ₃ is a third combinational logic circuit, and block "NOT" is NOT circuit (inverter circuit) , block "AND" logic product circuit, I, the first common input terminal, 1 ₂ and the second common input terminal, X, a first common input, X ₂ is a second common input is there.

The circuit in which the first and second common input terminals 1> I ₂ of these circuits are connected to the first and second output terminals 0, 〇 in FIG. 7 (third embodiment), It is a form of.

 (motion)

First, second, third combinational logic circuit, the logic output of the _{L 2 L 3 (:, B} , A respectively, the following logical expression is given by.

 C = ~ "X 1 ·, X 2,

 B = 1 ·, X 2,

 A = 1 · X 2,

Where the logical variable X, is the logical value of the output 1, the logical variable χ ₂ is the logical value of the output 2, “,” is a negation symbol (inversion symbol), and “·” is a logical product symbol (AND). Symbol).

 Incidentally, as for a combinational logic circuit, as is well known to those skilled in the art, if a logical expression is given, a circuit structure can be derived based on the logical expression. Therefore, as far as the combinational logic circuit is concerned, the circuit structure specification can be replaced by a logical expression.

 Clarify the difference between the logical outputs Α, Β, and C due to the difference in the level of the modulated frequency component (signal).

(1) When the same amplitude is at the dark level, since both X i and X 2 are 0, A = 0, B = 0, C = l,

 (2) When the amplitude is at the gray level, X, = 1 and 2 = 0,

 A = 0, B = l, C = 0,

(3) the same amplitude is, comes to be in the light level, X,, since X ₂ is 1 and both,

 A = l, B = 0, C = 0,

It is.

Bright level signal V (V≥ V _t2) is, to the common input terminal I, time t. Clarify the difference between the inversion times of logic outputs A, B, and C when they arrive.

 (a) Time zone t. <t <t, then x! , X 2 are both 0,

 A = 0, B = 0, C = l,

 (b) In the time zone t, ≤ t <t2, X, = 1 and X2 = 0,

 A = 0, B = 1, C = 0,

 (c) In the time zone t 2 ≤ t, both x> and x 2 are 1, so

 A = l, B = 0, C = 0,

Becomes

Gray level signal v ( _Vtl ≤ V < _Vt2 ), common input terminal I, time t. Clarify the difference between the inversion times of the logic outputs B and C when they arrive at.

 (a ') Time zone t. If t <t, 'then X,, X 2 are both 0,

 A = 0, B = 0, C = l,

 (b ') At time t,' ≤ t, x, = 1 and χ = 0,

Α = 0, B = l, C = 0, Becomes Of course, ", '> t,.

 The logic level Α is not inverted by the gray level signal v.

 (Tri-level detection system)

Reflectance large a region of the moving elongated object 1 ₃ surface (light level), regions of medium (high level), and describes the detection system small a region (dark level).

 Fig. 10 is an explanatory diagram of the detection system. In Fig. 10 (a), the upper part is a side view, the lower part is a plan view of a long object, and (b) is the operation of the detection system. FIG.

In FIG. 1 0 (a), 1 ₃ long object moving opaque or translucent, 2 a projection laser beam, 4-3 is light reflected by the long object 1 ₃ (speckle pattern light 4 to the regular reflection light 3). The arrow a shows the direction of movement of the long object 1 _3.

_On the surface of the long object 13, a dog area (A), a middle area (B), and a small area (C) having a reflectance as shown in the lower plan view of FIG. They exist alternately or in any order. There may be steps at the boundaries of each area.

Projected laser beam 2, to the long object 1 ₃ surface, is caused to obliquely or perpendicularly incident morphism.

 At the start point of the projection laser light 2 and at the end point of the reflected lights 4 to 3, a light emitting and receiving device (not shown) according to the fourth embodiment is arranged.

The upper portion of FIG. 1 0 (b), as the movement of the long object 1 _3, the reflectivity and signal level depending on its surface indicating that varies. The lower part of FIG. (B) is, OUT 1 and OUT 2 (Output 1 and Output 2 in Figure 8) is, as the movement of the long object 1 _3, represents that you change.

Long object 1 ₃ reflectance large a region (A) is the optical path of the projected laser beam 2 When traversing, since the signal level v of the input terminal I in Fig. 5 exceeds the judgment levels 1 and 2, both 0 UT 1 and 0 UT 2 become logic 1, and only the logic output A in Fig. 9 becomes 1.

 When the area (B) in the middle of the reflectivity traverses the projected laser beam 2, 0 UT 1 becomes logic 1 and 0 UT 2 becomes logic 0, and only the logic output B in FIG.

 When the area (C) having a low reflectivity crosses the projected laser beam 2, UT 1 and 0 UT 2 both become logic 0, and only the logic output C in FIG. Hereinafter, the same operation is repeated.

 According to such a ternary level detection system, three types of detection signals can be output as described above. Therefore,

 (1) Either logical output B or C can be used as a single detection signal.

 (2) Both logic outputs B and C can be used simultaneously as detection signals. In this case, logical output A is regarded as the background (not detected) output.

 (3) The logic output B can be used as a timing signal and the logic output C can be used as a detection signal.

 (Boundary detection system)

Reflectance large a region of the moving elongated object 1 ₃ surface (light level), the small a region (dark level), and describes the detection system both boundaries (gray level).

 Fig. 11 is an explanatory diagram of the detection system. In Fig. 11 (a), the upper part is a side view, the lower part is a plan view of a moving long object, and Fig. 11 (b) is the detection system. It is operation | movement explanatory drawing of.

In FIG. 1 1 (a), 1 ₃ long object moving opaque or translucent, 2 a projection laser beam, 4-3 is reflected light (speckle by the long object 1 ₃ Pattern light 4 to regular reflection light 3). The arrow a shows the direction of movement of the long object 1 _3.

The long object 1 ₃ the surface, as a plan view of the lower portion of FIG. 1 1 (a), the small a region of large a region (A) and the reflectance of the reflectance (C) is, exist alternately Exist. D is the boundary area between the two. Even if there is a step in the boundary area D, there is no problem.

Projected laser beam 2, to the long object 1 ₃ surface, is caused to obliquely or perpendicularly incident morphism.

 At the start point of the projection laser light 2 and at the end point of the reflected lights 4 to 3, a light emitting and receiving device (not shown) according to the fourth embodiment is arranged.

The upper portion of FIG. 1 1 (b), as the movement of the long object 1 _3, the reflectivity and signal level depending on its surface indicating that varies. The lower portion of FIG. (B) is, 0 UT 1 and 0 UT 2 (output of FIG. 8 1 and output 2), as the movement of the long object 1 _3, indicating that variation.

Long object 1 ₃ reflectance large a region (A) is, when traversing the optical path of the projected laser beam 2, since the signal level V of the input terminal I of FIG. 5 exceeds the decision level 1 and 2, 0 UT 1 and 0 Both UT 2 become logic 1 and only logic output A in Fig. 9 becomes 1.

 When the boundary area (D) traverses the projected laser beam 2, 0 UT 1 becomes logic 1 and 0 UT 2 becomes logic 0, and only the logic output B in FIG.

 When the area (C) having a low reflectivity crosses the projected laser beam 2, both 0UT1 and 0UT2 become logic 0, and only the logic output C in FIG. According to such a boundary detection system, as described above, three types of detection signals can be output. Therefore,

(1) The boundary area (D) can be detected by the logical output B = 1. (2) Logical output B = 1 can be used as a detection signal, and logical output A = 1 or C = 1 can be used as a control signal.

 (Transparent sheet edge position detection system)

 An edge position detection system for controlling the meandering of a running transparent sheet will be described.

 (Constitution)

 FIG. 12 is an explanatory view of the detection system, wherein FIG. 12 (a) is a side view and FIG. 12 (b) is an operation explanatory view of the same system.

In FIG. 12 (a), ₁₂ is a transparent sheet traveling in a direction perpendicular to the paper surface, A is the outside, C is the inside, and E is the edge. The solid line represents the transparent sheet at zero horizontal run-out (transverse), and the broken line represents the transparent sheet in the horizontal run-out state.

Reference numerals 5 and 6 denote projectors and receivers, reference numeral 2 denotes a projection laser beam, reference numeral 9 denotes a reflector, and reference numerals 4 and 3 denote light reflected by the reflector 9 (speckle pattern light 4 to specular reflection light 3). The reflection plate 9 does not need to be a mirror surface. The arrows b indicate the horizontal deflection direction of the transparent sheet 1 _2.

Figure 1, 2 (a), the emitter and receiver 5, 6 is arranged on the inner side above the transparent sheet 1 ₂ traveling, and its beam-like projection laser beam 2, the horizontal deflection midnight of Etsu di E Turned to

 The reflection plate 9 is arranged at a point on the extension of the projection laser beam 2 beyond the edge E.

Incidentally, the arrangement position of the emitter and receiver 5-6, transparent sheet 1 _second inner lower traveling, or outer upper Wakashi Ku may also be the outer lower. In any case, the beam-shaped projection laser beam 2 must irradiate the edge E at the time when the lateral deflection is zero.

(Action) The upper part of Fig. 12 (b) shows that the signal level V force of Fig. 8 changes in response to the meandering (lateral vibration) of the running edge E. The lower part of the figure (b) shows that UTUT1 and 0UT2 (output 1 and output 2 in FIG. 8) change in response to the lateral vibration of the edge E.

 That is, when the running edge E sways to the left on FIG. 12 (a), the bright level signal light returns from the reflector 9 to the receiver 6. Exceeds judgment levels 1 and 2, OUT 1 and 0 UT 2 both become logic 1, and only logic output A in Fig. 9 becomes logic 1.

When edge E is deflected to the right, the projection laser beam 2 is incident obliquely on the transparent sheet 1 _2, 2 times the forward, backward twice, is reflected 4 times convenience, reflecting their No light returns to the receiver 6. Therefore, the signal light returning to the light receiver 6 does not reach even the judgment level 1, so that both UT1 and 0UT2 become logic 0, and only the logic output C in FIG. 9 becomes logic 1.

 When the lateral deflection of the edge E is zero, a part of the light beam of the projection laser beam 2 does not reach the reflector 9 because it is incident and refracted near the inside of the edge E and changes its traveling direction. The remainder of the light beam passes near the outside of the edge E and reaches the reflector 9, becomes reflected light 4 to 3, passes through the vicinity of the outside of the edge E in the opposite direction, and returns to the light receiver 6. come. The signal V (FIG. 5) obtained by photoelectrically converting the reflected lights 4 to 3 has a judgment level of 1 or more and a judgment level of less than 2. That is, the ash level.

 The three outputs A, B and C of the transparent sheet edge position detection system can be used as control signals for the transparent sheet edge position control system (EPC).

(1) Output B of the combinational logic circuit L ₂ of FIG. 9 can and becomes logical 1, the transparent sheet one Bok of edge E is (no lateral motion occurs) is in the normal position for run lines that Means

 (2) When the output A of the combinational logic circuit L3 in the figure becomes logic 1, it means that the edge E swings (blurs) inside the traveling path (left side in the figure).

 Therefore, the output A can be used as a control signal for restoring the edge E that has swayed inward (blurred) to a normal position.

 (3) When the output C of the combinational logic circuit in FIG. 9 becomes logic 1, it means that the edge E swings (blurs) outside the traveling path (right side in the figure).

 Therefore, the output C can be used as a control signal for restoring the edge E that oscillates (blurs) outside the traveling path to a normal position. Industrial applicability

 Since the invention of this application is configured as described above, remarkable effects can be obtained as described in the following (a) to (n).

 (a) By projecting coherent visible light 2 in the form of a very fine beam and introducing a logarithmic amplifier 63, both targets at ultra-long distances and targets at short distances can be adjusted without sensitivity. (As is), it is possible to detect equally.

(B) if (Though) be the gradient of the target surface to the ultrafine beam-like co Hire emissions Bok visible light 2 changes rather large, weak speckle pattern light 4 coming by the photoelectric converter 6 ₂ By converting the signal into an electrical signal and performing logarithmic amplification, the target can be reliably detected.

 (c) Even if the target is a dog with a low light reflectance or a target with a low light reflectance, it can be detected equally evenly without adjusting the sensitivity.

(d) Both large and small targets can be detected equally with no sensitivity adjustment. (e) High resolution could be achieved by squeezing the beam-west monster very small.

 (f) Smoke in colorless or translucent brown or translucent bottles or cylinders can be detected.

 (g) Water in colorless and transparent bottles or cylinders can also be detected.

 (h) The current component (ie, DC component) derived from natural light or illumination light was completely blocked, and it was extremely easy to extract the current component (AC component) derived from signal light.

 (i) The dynamic range has been greatly expanded, eliminating the need to select and like target targets.

For (j) weak speckle pattern light formed by photoelectrically converting 1 0 microamperes following weak current (voltage), since it is possible to strongly extension amplification Te logarithmic amplifier 6 ₃ Niyotsu, the laser diode 5 ₂ low optical power (e.g., 1 m W) and a can detect a target object even. Therefore, there is no danger of injuring the human eye, and it is safe.

(K) from the laser diode 5 ₂ and low light output, it is possible to reduce current consumption of the DC power supply 8.

(1) For a large current (voltage) which is formed by photoelectrically converting a strong regularly reflected light, since it is possible to compression amplified by a logarithmic amplifier 6 _3, it is possible to lower the operating voltage of the linear amplifier. Therefore, the voltage of the DC power supply 8 can be reduced to, for example, about 5 volts.

 (m) The sender and receiver can be connected in parallel and integrated. Therefore, the size can be reduced.

 (n) Therefore, it can be realized at low cost.

Claims

1. An emitter (5) for projecting a low-frequency intermittently modulated beam-shaped coherent light (2) toward the monitored space;  A receiver (6) for receiving any reflected light including the speckle pattern light (4) coming from the monitored space;  Contains 口 主 冃 The projector (5) contains a low frequency oscillator (5 _4), a laser diode (5 _2), and a projection optical system (5,), The low-frequency oscillator (5 ₄₎ outputs a low-frequency modulation wheel signal, the low frequency  G Modulated signal, the Intermittent the囲源circuit electrodeposition of the laser diode (5 ₂₎ at low frequencies, And I go-between, the laser diode (5 _2), and outputs the Nohi one-les-down Bok light intermittent modulation at a low frequency,  The light-projecting optical system (5,) condenses the low-frequency intermittently modulated coherent light and forms the low-frequency intermittently modulated beam-shaped coherent light (2). ), And It said light receiver (6) includes a photoelectric converter (6 _2), a logarithmic amplifier (6 _3), the DC regenerator (6 _4), a comparator (6 _5), the comparison voltage generator (6 _S) Containing The photoelectric converter (6 ₂₎ is any reflected light including speckle pattern light 4 arriving on the light-receiving surface to photoelectric conversion, Outputs an electrical analog signal, Said logarithmic amplifier (6 _3), can the amplitude of the electrical analogue signal is small makes the extension amplification, the can a large becomes, and the compression amplification, extension or compression Output a signal, The DC regenerator (6 _4), the DC component in the extended or compressed signals as well as deter, the modulation frequency component in the signal rectified and smoothed, and outputs a reproduced DC signal, Inverting input terminal of the comparator (6 ₅₎ (-) the reproduced DC signal voltage is applied to the comparison voltage of the comparison voltage generator (6 ₆₎ is applied to the non-inverting input terminal (+), when the magnitude relation between both voltages is reversed, the comparator (6 _5), the entry young properly of the target (1) in the monitored space and outputs a detection signal for notifying the existing call (7),  Target detection system using speckle pattern light.  2. The target detection device using the speckle pattern light according to claim 1, wherein the target force is also: The DC regenerator (6 ₄₎ has an input terminal (I), the output terminals (u,),及Beauty Grad down de terminal, and the reverse rectifying diode in series branch), and two terminals of the parallel branch Contains a smoothing circuitR,)  The two-terminal smoothing circuit (C, R,) consists of a parallel connection circuit of smoothing capacitors (C,) and discharge resistors).  The input terminal (I) is connected to the cathode terminal of the reverse rectifier diode),  The anode terminal of the reverse rectifier diode (Dt) is connected to the opposite ground terminal (s,) of the two-terminal smoothing circuit (C, R,).  The ground terminal of the two-terminal smoothing circuit (C, R.) is connected to the positive terminal of the DC power supply (Vcc), and the negative terminal of the same power supply (Vcc) is connected to ground. The opposite ground terminal (s,) of the two-terminal smoothing circuit (C, R C) is Through the output terminal (u,), connected to the inverting input terminal (I) of the comparator (6 _5), The comparison voltage generator (6 ₆₎ has an input terminal (I), the output terminal (u ₂₎ and Grad down mode pin, and, in the series branch of the forward rectifying diode (D ₂₎ and parallel branches 2 Contains terminal smoothing circuit (C ₂ · VR ₂ ) The two-terminal smoothing circuit (C ₂ · VR ₂ ) is composed of a parallel connection circuit of a smoothing capacitor C ₂ and a resistor divider with smooth terminals (VR ₂ ). The input terminal (I) is connected to the anode terminal of the forward rectifier diode (D ₂ ), Cathode terminal of the forward rectifier diode (D ₂₎ is connected to a counter-ground side terminal of the two terminals smoothing circuits _{(C 2 · VR 2) (} s 2), The ground side terminal of the above two-terminal smoothing circuit (C ₂ · VR ₂ ) is connected to ground, The sliding terminal of the resistor divider (VR ₂₎ is to through the output terminal (u,), the comparator is connected to the non-inverting input terminal (6 ₅₎ (+), by speckle pattern light Target detection device.  3. An object detection device using the speckle pattern light according to claim 1 or 2, and Containing second sliding terminal resistor-divider (VR ₃₎ and a second comparator (6 _52), High-voltage side terminal of the second sliding terminal resistor-divider (VR ₃₎ is connected to the sliding terminal of the resistor divider (VR _2), Inverting input terminal of the comparator (6 ₅₎ (-), said reproduction DC signal voltage (V,) is applied, its non-inverting input terminal (+), the first resistor divider the output voltage of the sliding pin _{(VR 2) (α 'V} 2) is applied, Above the inverting input terminal of the second comparator (6 _S2) (I), the reproduced DC signal voltage is applied, its non-inverting input terminal (+), the second resistive voltage divider (VR ₃ ) the output voltage of the sliding pin (/ 3 alpha 'V ₂₎ is applied, the output 1 (X is the output of the comparator (6 ₅₎₎ is applied, said second comparator (6 ₅₂ ) Output 2 (X ₂ )  Target detection device using speckle pattern light.  4. A target detecting apparatus using the speckle pattern light according to claim 3, and First combinational logic circuit (L,), a second combinational logic circuit (L _2), contain及beauty third combinational logic circuit (L _3), X common first input thereto, when the second input to the chi _2, its these logic output A, B, and C, respectively,  A = X 1 X 2,  B = X 1 · X 2,  =, X 1 · X 2,  However, one is given by a negation sign (reversal sign), · is an AND sign,  Target detection system using speckle pattern light.  5. A target detection device using the speckle pattern light according to any one of claims 1 to 4, and The photoelectric converter (6 ₂₎ preceding the light receiving optical system (6) is arranged, the light receiving optical system (6) is any reflected light including speckle pattern light coming from said monitored space, It focused on the light receiving surface of the photoelectric converter (6 _2), Target detection system using speckle pattern light. 6. A target detection device using the speckle pattern light according to any one of claims 1 to 5, and  The light emitting device (5) and the light receiving device (6) are arranged in parallel and integrated, thereby forming a light emitting and receiving device.  A target detection device that uses the light of a trickle pattern. 7. A target detection device using the speckle pattern light according to claim 4 and a reflector (9). The target object detection device, when one edge of the transparent sheet for the long (1 ₂₎ (E) is running on the prescribed lateral line of a given travel path, the beam-like Nohi one Ren Bok The light (2) is disposed at a position obliquely irradiating the edge (E), and the reflector (9) is located on an extension of the beam-shaped coherent light (2), and Is positioned beyond the edge (E), and when the edge (E) is on a predetermined side line of a predetermined traveling path without causing a lateral shake, the target detection is performed. only the output of the second combination logic circuit of the device (L ₂₎ (B) is a logic 1, and the  When the edge (E) swings inward, only the output (A) of the third combinational logic (L3) becomes logic 1, and  When the edge (E) swings outward, only the output (C) of the first combinational logic circuit (L,) becomes logic 1,  Edge position detection system for transparent sheets.