JPH0812107B2 - Mirror-scanning radiation detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention detects the amount of radiated light of an object to be inspected which is present at any location within a range from a short distance to a long distance to judge the object to be inspected. It relates to a mirror scanning radiation detector that can be implemented.

(Prior Art) Conventionally, fire detectors have been known as radiation detectors that detect the amount of radiated light of an object to be inspected that is present at any location within a range from a short distance to a long distance to determine the object to be inspected. Has been. This fire detector guides the amount of radiated light of the test object at a predetermined location to the photoelectric conversion element, and determines whether the test object detection signal as the detection output of the photoelectric conversion element exceeds the reference level. We are trying to determine if there is a fire.

However, with this fire detector, the presence or absence of a fire is detected by comparison with the reference level, and the detection output differs depending on whether the test object is at a short distance or at a long distance, and the If the reference level is set together, the detection output of the test subject at a long distance becomes smaller than the reference level, and even though a fire has occurred, it cannot be detected that it is a fire, If the reference level is set low together, there is a problem that a cigarette or the like that is not the object to be inspected at a short distance is erroneously detected as an object to be inspected. However, there is a problem that the subject cannot be detected accurately.

(Problems to be Solved by the Invention) Therefore, in Japanese Patent Laid-Open No. 59-186094, based on the fact that there is infrared rays peculiar to a fire as a fire detector, the infrared rays are within a range from a short distance to a long distance. With the purpose of detecting each different position of the object to be inspected, slits are formed at predetermined angles in the rotation direction of the rotating disk, and the positions where the slits are formed are shifted in the radial direction, from short distances to long distances. In order to scan the object to be inspected within the range of, the rotating disk is rotated to pass the radiated light amount of the object to be inspected to the infrared detection element by passing through the slits at different positions, and the detection of this infrared detection element It has been proposed that the output is position-corrected by the slit passing position so that the test object can be accurately detected regardless of whether the test object is in a short distance or a long distance. However, the one disclosed in Japanese Patent Laid-Open No. 59-186094 has a structure in which each slit is formed on a rotating disk and the object to be detected is detected by passing through each slit, so that the detection field of view is narrowed. There is.

(Object of the Invention) The present invention has been made in consideration of the above circumstances, and its object is to accurately detect an object to be inspected within a range from a short distance to a long distance without narrowing a detection visual field. Another object of the present invention is to provide a mirror scanning type radiation detector capable of detecting light.

(Means for Solving the Problems) A mirror scanning radiation detector according to the first invention of the present application is such that an object to be inspected within a range from a short distance to a long distance is sequentially scanned by a scanning mirror. Of the radiant light to the photoelectric conversion element, the scanning unit photoelectrically converting the radiant light detected within the scanning range and outputting it as a test object detection signal, an initial value is predetermined, and up to the test object When the distance is short, the level is set relatively higher than when the distance is far, and when the distance to the subject is far, the level is set relatively lower than when the distance is short. Based on the reference level setting unit that sequentially outputs the reference level signal by increasing / decreasing the initial value in proportion to the distance to the object to be inspected that changes within the range of the short distance to the long distance, and the level of the reference level signal. Before By comparing the level of the subject target detection signal, and having a determination unit for determining the test subject.

A mirror scanning radiation detector according to a second invention of the present application sequentially scans within a range from a short distance to a long distance by a scanning mirror, and guides radiation to be inspected within the range to a photoelectric conversion element, A scanning unit that photoelectrically converts radiated light detected within the scanning range and outputs it as a test object detection signal, and stores an initial value, and when the distance to the test object is short compared to when the distance is far, Change within the range from short distance to long distance based on the scanning so that the level is set relatively high and the level is set relatively low when the distance to the subject is long compared to when the distance is short. A storage unit that stores in advance a reference level signal obtained by increasing or decreasing the initial value in proportion to the distance to the subject to be tested, and a reference level that sequentially outputs the reference level signal corresponding to the scan from the storage unit. And tough, by comparing the level of the said test object detection signal of said reference level signal, and having a determination unit for determining the test subject.

(Operation) According to the mirror scanning type radiation detector of the first invention of the present application, the radiation light of the object to be inspected within the range of the short distance to the long distance is guided to the photoelectric conversion element by the scanning of the scanning mirror. The photoelectric conversion element converts the emitted light into a detection signal to be detected. The detection signal of the object to be inspected sequentially changes as it scans from a short distance to a long distance.

The reference level setting unit sets the level of the reference level signal to be low when the distance to the test object is long by increasing and decreasing the initial value sequentially in proportion to the distance, and the distance to the test object. When is close to, the level of the reference level signal is set high. The determination unit determines the test target by comparing the level of the reference level signal and the level of the test target detection signal.

According to the mirror scanning type radiation detector of the second invention of the present application, the radiation light of the object to be inspected within the range from the short distance to the long distance is guided to the photoelectric conversion element by the scanning of the scanning mirror. The photoelectric conversion element converts the emitted light into a detection signal to be detected. The detection signal of the object to be inspected sequentially changes as it scans from a short distance to a long distance. The reference level setting unit sets a relatively high level when the distance to the subject to be inspected is short and a relatively high level when the distance to the subject to be inspected is long, and a relatively high level when the distance to the subject to be inspected is far compared to when the distance is short. The reference level signal whose initial value is increased or decreased in proportion to the distance to the object to be inspected, which changes within the range from short distance to long distance based on scanning, is sequentially read and output according to scanning. Let The determination unit determines the test target by comparing the level of the reference level signal and the level of the test target detection signal.

(Example) Hereinafter, an example in which the mirror scanning radiation detector according to the present invention is applied to a fire detector will be described with reference to the drawings.

In FIG. 1, reference numeral 10 indicates a main body of a fire detector as a mirror scanning type radiation detector. This main body 10
It comprises a housing 12, a support body 14 for rotatably supporting the housing 12, and a base portion 16 fixed to a building structure. The housing 12 has a hood 18, a shaft 20, and
Bolts 22 and are installed. The support 14 is formed in a substantially U shape, and the support 14 has an insertion hole 24 and an arc-shaped guide groove 26.
And have been drilled. The shaft 20 fixed to the housing 12 is inserted through the insertion hole 24, and the bolt 22 is guided by the guide groove 26.
Is threaded through the housing 12 and is screwed to the housing 12, and the arc center of the guide groove 26 is at the position of the shaft 20. This housing 12 is
The tilt is adjusted in the vertical direction about 20 and the bolt 22 is tightened after the adjustment so that the bolt 22 is held at a predetermined angle with respect to the horizontal direction H.

The housing 12 is connected to a signal processing circuit, which will be described later, by a cable 28, and in the housing 12, a protective glass 34, a motor 38 for rotating a rotary mirror 36, an objective lens 40, as shown in an enlarged view in FIG. A mirror 42, a slit plate 44 for limiting the field of view, a relay lens 46, a photoelectric conversion element 48, and an eyepiece lens system 52 are housed. The rotating mirror 36 functions as a scanning mirror that scans within a range from a short distance to a long distance, and includes a motor 38 and an objective lens 4
The 0, the mirror 42, the slit plate 44, the relay lens 46, and the photoelectric conversion element 48, together with the rotary mirror 36, constitute a scanning unit. The hood 18 plays a role of preventing the protective glass 34 from being soiled and a role of cutting ambient light.

The photoelectric conversion element 48 has a function of converting the emitted light of the object to be inspected within the range from the short distance to the long distance into a detection signal of the object to be inspected. The emitted light from the subject is a rotating mirror.
After being reflected by 36, it passes through the objective lens 40, is reflected by the mirror 42, forms an image on the slit plate 44, and the slit
The radiated light passing through 50 is guided to the photoelectric conversion element 48 by the relay lens 46.

Here, as shown in FIG. 3, the fire detector scans the object to be inspected within the range of the short distance θ ₁ to the long distance θ _n in the horizontal direction (angle θ direction), and is also shown in FIG. As described above, the subject can be scanned in the vertical direction (altitude angle r direction) within the range of the short distance r ₁ to the long distance r _n . In FIGS. 3 and 4, white circles indicate The rotary mirror 36 of the main body 10 of the fire detector is shown, and the reference numeral 200 is a building structure. The main body 10 of the fire detector is the building structure 200.
It is installed above.

The rotating mirror 36 scans from the lower side to the upper side in the direction of arrow A shown in FIG. 2 by its rotation.
The initial scanning position in the horizontal direction θ ₁ is the rotating mirror 36.
It is set by collimating the eyepiece lens system 52 while rotating the. Motor 38 control signal and photoelectric conversion element 48
The detection object detection signal of (1) is transmitted and received to and from the signal processing circuit via the cable 28. Here, the optical elements housed in the housing 12, including the housing 12, are motors.
Together with 38, it constitutes a vertical scanning unit as a first scanning system.

The base 16 is connected to a control calculation unit 130 described later via a cable 30. The base 16 has a motor 32 built-in and a support body driving means (not shown) built therein. The motor 32 constitutes a part of a second scanning system for rotating the support 14 in the horizontal direction in response to a control signal from the control calculation unit 130. The second scanning system is a horizontal scanning unit for changing the vertical scanning unit in the horizontal direction. Functions as a scanning unit.

The fire detector has a reference level setting unit as shown in FIG.
100, a comparator 124, a control calculation unit 130, a scanning unit 140 for issuing various commands, a display unit 150 for displaying based on signals from the control calculation unit 130, and a signal processing circuit including a memory 160. are doing. The reference level setting unit 100
Along with the control calculation unit 130 and the memory 160, a low level is set as a reference level signal when the distance to the subject to be detected by scanning by the scanning unit is long, and the distance to the subject to be detected is set. When is close, it plays a role of setting a high level as a reference level signal.

The reference level setting unit 100 includes a clock circuit 112 and a frequency divider 11
4, a counter 116, a D / A converter 118, a buffer 120, and an initial value setting unit 122. Comparator 124
And the control calculation unit 130 function as a determination unit that determines the test target by comparing the level of the reference level signal and the level of the test target detection signal. Clock circuit
112 forms a pulse having a predetermined cycle and outputs the pulse to the frequency divider 114. The frequency divider 114 frequency-divides the clock pulse from the clock circuit 112 based on the control signal of the control calculation unit 130 and determines the period. The value is changed and output to the counter 116. This change in the period is related to the change in the level of the reference level signal.

The initial value setting unit 122 sets an initial value based on the control signal from the control calculation unit 130 and outputs the initial value to the counter 116, and the counter 116 starts counting after the initial value is set. . The output of the counter 116 is the D / A converter 11
The analog signal is input to the comparator 8, converted into analog, and input to the comparator 124 via the buffer 120 as a reference level signal. Here, this reference level signal is used to determine whether the test object is a fire or not, and when the level of the test target signal exceeds the level of the reference level signal, a fire is detected. It is determined that there is a fire, and when the level of the signal to be inspected is lower than the level of the reference level signal, it is determined that there is no fire. The signal to be tested of the photoelectric conversion element 48 is input to the comparator 124 via the amplifier 48a, compared with the reference level signal from the buffer 120, and a comparison result signal is output to the control calculation unit 130.

The control calculation unit 130 controls the motor 38 of the first scanning system and the motor 32 of the second scanning system, and performs various operations based on various information such as the installation status of the fire detector input from the operation unit 140. In addition to outputting the control signal to the circuit, the fire occurrence position signal is displayed according to the output of the comparator 124 to the display device 150 and is output to the outside via the interface 152.

From the operation unit 140, the horizontal detection direction θ _i (i = 1, 2,
, N), the initial value K _i of the reference level signal k, the frequency division ratio j _i of the frequency divider 114, and the increase / decrease information of the count are input according to the installation status of the fire detector. Initial value K _i of reference level signal, frequency division ratio j _i , and count increase / decrease information are stored in memory 160
The initial value K _i is output to the initial value setting unit 122, the frequency division ratio j _i is output to the frequency divider 114, and the count increase / decrease information is output to the counter 116.

Here, the initial value K _i corresponds to the initial level of the reference level signal k at θ _i , the frequency division ratio j _i corresponds to the gradient of the level of the reference level signal k at θ _i , and the count increase / decrease information is It is composed of an increase command signal for increasing the level of the reference level signal k and a decrease command signal for decreasing the level of the reference level signal k. The details of the operation of this fire detector will depend on the installation situation of the fire detector. Will be explained together.

First, the control calculation unit 130 controls the motor 32 so that the housing 12 faces the θ ₁ direction (see FIG. 3). Next, the control calculation unit 130 rotates the motor 38 to perform scanning from the r ₁ direction to the r _n direction, and at that time, from the memory 160, the initial value K _{1 in} the θ direction, the frequency division ratio j ₁ , and the decrease command signal. Initial value setting section
It outputs to 122, frequency divider 114, and counter 116.

The counter 116 is set to the initial value K ₁ , and the D / A converter 11
8. The initial level k ₁ of the reference level signal k shown in FIG. 6 is generated via the buffer 120. As the altitude angle increases with the rotation of the motor 38, the distance to the building structure 200 increases, but the counting circuit 116 receives the frequency-divided pulse of the frequency divider 114 that divides the clock pulse of the clock circuit 112. Of the reference level signal k decreases, and the level of the reference level signal k decreases.

Then, when the high angle exceeds the r _x direction, the distance to the building structure 200 becomes short again, so the control calculation unit 130 outputs an increase command signal to the counter 116, and the level of the reference level signal k becomes high again. . The comparator 124 sequentially compares the level of the reference level signal k and the detection target detection signal. When the detection of the θ ₁ direction is completed, the control calculation unit 130
Controls the motor 32 so that the housing 12 faces from the θ ₁ direction to the θ ₂ direction, and also sets the initial value k _{2 in the} θ ₂ direction, the frequency division ratio j ₂ , and the data of the count increase / decrease information to the initial value setting unit 122, It detects toward the frequency divider 114 and the counter 116. And θ ₁
The same scanning as the scanning in the direction is performed. This scan is θ
The scanning is repeated from the _first direction to the θ _n direction until the scanning is completed, and the first scanning of the entire scanning range in the horizontal direction and the vertical direction is completed.

Here, for example, as shown in FIG. 7, if a cigarette fire different from the regular test object is detected in the r _y direction and a fire as the regular test object is detected in the r _z direction, Since the level of the reference level signal k is high as shown in FIGS. 8 and 9, even if a cigarette fire is detected at a short distance, it is prevented that the cigarette fire is erroneously detected as a legitimate object to be inspected. Even if there is a fire as a legitimate subject to be inspected at a long distance, the reference level signal k is set to a low level, so that the legitimate subject to be inspected is not a proper subject to be inspected. Detection is prevented.

FIG. 10 is a block circuit diagram showing another embodiment of the reference level setting unit. Instead of providing a clock circuit 112, a frequency divider 114, an initial value setting unit 122, a counter 116, a memory 18 is provided.
0 is provided, and the memory 180, the D / A converter 118, and the buffer 120 constitute the reference level setting unit 100. In the memory 180, by operating the operation unit 140, the entire scanning range (θ _i , i = 1,2, ..., n; r _i , i = 1,
The numerical value corresponding to the level of the reference level signal k in 2, ..., N) is stored, and at the time of scanning, the control calculation unit 130 sequentially reads the levels of the reference level signal corresponding to the detection direction from the memory 180 and D / A. After being converted to an analog signal by the converter 118, it is transmitted to the comparator 124 via the buffer 120, and the comparator 124 compares it with the detection target detection signal.

(Effects of the Invention) Since the mirror scanning radiation detector according to the present invention is configured as described above, it is possible to accurately detect a test object within a range from a short distance to a long distance without narrowing the detection field of view. Has the effect.

Further, since the present invention has a configuration in which the reference level is changed according to the distance, it is possible to prevent the S / N ratio from decreasing even when the detection signal includes noise.
It is possible to detect an object to be inspected (for example, a fire) without lowering reliability regardless of whether the object to be inspected is near or far.

[Brief description of drawings]

FIG. 1 is a side view showing the structure of the main body of a mirror scanning radiation detector according to the present invention, and FIG. 2 is an enlarged perspective view showing the housing of the mirror scanning radiation detector in an enlarged scale together with its internal structure. 3 and 4 are explanatory views showing the installation state of the mirror scanning radiation detector, FIG. 3 shows the installation state in the horizontal direction, and FIG. 4 shows the installation state in the vertical direction. FIG. 5 is a block circuit diagram of a mirror scanning type radiation detector according to the present invention, and FIGS. 6 to 8 are views for explaining the operation of the mirror scanning type radiation detector according to the present invention. Therefore, FIGS. 6 and 8 are diagrams showing a state in which the level of the reference signal changes with the distance from a short distance to a long distance, and FIG. 7 is a diagram showing an example of the detection condition of the object to be inspected. FIG. 9 is a signal comparison diagram for explaining the determination by the setting unit of the mirror scanning type radiation detector, FIG. 10 is another embodiment of the reference level setting section according to the present invention. 10 …… Main body, 14 …… Support, 36 …… Rotating mirror, 32,38 …… Motor, 40 …… Objective lens, 48 …… Photoelectric conversion element, 100 …… Reference level setting section, 130 …… Control Computational unit, 124 …… Comparator, 140 …… Operating unit, 160 …… Memory.

Claims (4)

[Claims] 1. A radiant light detected within the scanning range by sequentially scanning a range from a short distance to a long distance by a scanning mirror to guide radiated light of a test object within the range to a photoelectric conversion element. And a scanning unit for photoelectrically converting and outputting as a detection object detection signal, an initial value is predetermined, and when the distance to the inspection object is short, the level is set relatively higher than when the distance is far and When the distance to the object to be inspected is long, the level is set relatively lower than when the distance is short, so that the level is proportional to the distance to the object to be inspected, which changes within the range from the short distance to the long distance based on the scanning. The reference level setting unit that sequentially outputs the reference level signal by increasing / decreasing the initial value and the reference level signal, and compares the level of the reference level signal with the level of the detection target detection signal to determine the inspection target. Mirror scanning radiation detector; and a that judgment unit. 2. The scanning mirror is a rotating mirror, and the scanning unit has a vertical scanning unit whose scanning direction is a vertical direction based on rotation of the rotating mirror, and a scanning direction by rotating the vertical scanning unit in a horizontal direction. 2. The mirror scanning radiation detector according to claim 1, further comprising a horizontal scanning unit having a horizontal direction of. 3. The mirror scanning radiation detector according to claim 1, wherein the reference level setting unit includes a storage unit that stores in advance each initial value corresponding to the scanning direction. . 4. Radiation light detected within the scanning range by sequentially scanning within a range from a short distance to a long distance by a scanning mirror to guide radiation light to be inspected within the range to a photoelectric conversion element. And a scanning unit for photoelectrically converting and outputting as a detection object detection signal, and storing an initial value, and when the distance to the object to be inspected is short, the level is set relatively higher than when the distance is far and the object to be inspected is set. When the distance to the inspection object is long, the level is set relatively lower than when the distance is short, so that the level is set in proportion to the distance to the object to be inspected, which changes within the range from the short distance to the long distance based on the scanning. A storage unit that stores in advance a reference level signal obtained by increasing or decreasing the initial value, a reference level setting unit that sequentially reads out and outputs the reference level signal according to the scanning from the storage unit, and a level of the reference level signal. Serial by comparing the level of the subject object detection signal, the mirror scanning radiation detector; and a determination unit for determining the test subject.