JP2008292341A - Infrared ray sensor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an infrared ray sensor device, making a clear distinction by detecting two or more detection objects having a large difference in threshold of detection such as people and a flame in the case of a fire using one sensor. <P>SOLUTION: This infrared ray sensor device includes: a sensor diode D for detecting infrared rays; a constant-current circuit 5 for supplying currents different in current values to the sensor diode D; and a control part 10 for controlling the current value supplied from the constant-current circuit 5 to the sensor diode D. The control part 10 controls the output depending on a first period for supplying a first current from the constant current circuit 5 and a second period for supplying a second current larger than the first current. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an infrared sensor device capable of detecting, for example, two or more detection objects having a large difference in detection threshold.

  Conventionally, when detecting a flame in the case of a fire or the like as well as human detection, detection is performed by combining a visible light image sensor and a thermal image sensor.

  For example, in Patent Document 1, a visible monitoring image is obtained from a visible camera, and the image is processed to store abnormal contents such as fire and smoke, and the abnormality occurrence location in the monitoring image, and thermal monitoring is performed from an infrared camera. By obtaining an image and processing it, the contents of the abnormality such as fire and smoke and the location of the abnormality in the monitoring image are stored, and the CPU makes a comprehensive judgment using these two types of stored information. A system for stable monitoring is shown

  Further, in Patent Document 2, a single infrared sensor is used, and a human body amplification circuit and a flame amplification circuit are provided. In normal times, the output of the infrared sensor is amplified by a human body amplification circuit with a switch and monitored. In this case, when a high temperature of 40 ° C. or higher is detected, a system for detecting a fire and a human body by amplifying the output of an infrared sensor by a flame amplifier circuit using the switch is shown.

JP 2002-204445 A Japanese Patent Laid-Open No. 10-283579

  As described above, conventionally, when detecting a flame in the case of a fire or the like as well as human detection, a sensor and an amplifier corresponding to each of them are necessary, and there is a problem that the configuration becomes large, and the cost is high. There was a risk of connection.

  The present invention has been made in view of the current situation in conventional monitoring as described above, and its purpose is not only to detect an object corresponding to one threshold value by one sensor but also to a threshold value having a large difference from the above threshold value. An object of the present invention is to provide an infrared sensor device capable of distinguishing objects to be detected.

  An infrared sensor device according to the present invention includes a sensor diode that detects infrared rays; a constant current circuit that supplies currents having different current values to the sensor diode; and a control unit that controls a current value supplied from the constant current circuit to the sensor diode; In the infrared sensor device, the control unit includes a first period for supplying the first current from the constant current circuit and a second period for supplying a second current larger than the first current. It is characterized by output control.

  A sensor diode that detects infrared rays changes in IV characteristics in response to infrared heat. When the same constant current is applied, for example, a person is in the detection range and a flame is in the detection range. In the case temperature, the output voltage in the latter case is larger than that in the former case. On the other hand, by giving different currents for human detection and flame detection, a sufficiently large output can be obtained for detection in the presence of a person or the occurrence of a flame, and when any different current is supplied It is determined whether it is. In this way, an object having a difference in detection threshold is detected.

  The infrared sensor device allows an infrared image sensor provided with a plurality of sensor diode cells. The control unit may or may not be mounted on the LSI constituting the infrared image sensor. It is preferable to determine whether the person is a fire or a fire by comparing the output level with a predetermined threshold.

  For example, in order to detect not only a person but also a flame in the case of a fire or the like and enable distinction, a current that greatly varies the output level in each case is supplied from a constant current circuit. A configuration in which different currents are supplied by one constant current circuit or a configuration in which different currents are supplied from a plurality of constant current circuits is allowed.

  In the infrared sensor device according to the second aspect of the present invention, the control unit performs output control by alternately repeating the first period and the second period.

  In the infrared sensor device according to the third aspect of the present invention, when the output of the sensor diode in the first period is equal to or greater than a predetermined value, the infrared sensor apparatus is locked only in the first period or the second period.

  In the infrared sensor device according to the present invention of claim 4, the control unit executes a human body detection mode for detecting a human body in the first period, and executes a fire detection mode for detecting a fire in the second period. Features.

  Since the infrared sensor device according to the present invention supplies currents having different current values to the sensor diode, when each current is applied, a required output corresponding to the temperature is performed, and the difference in detection threshold is In the case of two or more large detection objects, a sufficiently large output is obtained, and it is determined which of the different currents is supplied, and two or more detection objects having a large difference in detection threshold are detected. It is possible to distinguish.

  In the infrared sensor device according to the second aspect of the present invention, the output is controlled by alternately repeating the first period and the second period, so that two or more detection objects having a large difference in detection threshold are detected. Will be repeated alternately, enabling appropriate monitoring.

  In the infrared sensor device according to the third aspect of the present invention, when the output of the sensor diode in the first period is greater than or equal to a predetermined value, it is locked only in the first period or the second period. When one object is detected, it can be locked only to the detection of this object, or it can be locked to a current for detecting another object, enabling appropriate and appropriate monitoring.

  In the infrared sensor device according to the present invention of claim 4, the control unit executes a human body detection mode for detecting a human body in the first period, and executes a fire detection mode for detecting a fire in the second period. It is possible to accurately distinguish between the detection of a person and the flame in the case of a fire.

  Embodiments of an infrared sensor device according to the present invention will be described below with reference to the accompanying drawings. In each figure, the same components are denoted by the same reference numerals, and redundant description is omitted. In FIG. 1, the block diagram of the Example of the infrared sensor apparatus based on this invention is shown. The infrared sensor device includes a pixel sensor unit 2 in which cells 1 including sensor diodes D that detect infrared rays corresponding to pixels are arranged in an array.

  A drive circuit 4 is connected to the signal line 3 connected to the cathode side of each sensor diode D in the cell 1 for one row. The drive circuit 4 supplies power through the signal line 3 to drive any one row of cells.

  A constant current circuit 5 that is connected to the anode side of each sensor diode D in the cell 1 for one column and supplies a current to the sensor diode D for one row is provided. The constant current circuit 5 is a circuit that supplies currents having different current values, and provides different currents for human detection and flame detection.

  Specifically, the IV characteristic of the sensor diode D has temperature dependence, and the slope becomes steep corresponding to the temperatures T1, T2, and T3 (T1 <T2 <T3) as shown in FIG. In order to detect the flame, for example, by passing the current I1 from the constant current circuit 5, when the flame occurs with respect to the temperature T1 in a steady state, the temperature becomes T3, and the output voltage changes from V1 to V3. Flame detection can be performed by detecting the voltage V3 with an appropriate threshold.

  On the other hand, in the presence of a person, if the temperature T2 is reached, a current I2 larger than the current I1 passed for flame detection is passed from the constant current circuit 5 to the sensor diode D. When the output voltage V2 is obtained with respect to the temperature T1 in the steady state, the temperature becomes T2 due to the arrival of the person and the infrared ray (temperature) by the person, so the output voltage changes from V2 to V4, Human detection can be performed by detecting the output voltage V4 with an appropriate threshold.

  An output scanning circuit 6 is connected to a connection point between the constant current circuit 5 and the sensor diode D. The output scanning circuit 6 is configured to take out an output signal from the sensor diode D in a single vertical line through the signal line 7, and the taken out output The signal is sent from the readout circuit 8 to the signal processing unit 20. The signal processing unit 20 has a configuration for performing image processing and the like.

  The control unit 10 obtains the output of the reading circuit 8 and controls the driving circuit 4, the constant current circuit 5, and the output scanning circuit 6 to control signal reading, and further, the output current value of the constant current circuit 5. Control to switch between. In the control for switching the output current value of the constant current circuit 5, a first period during which the first current (I1 in FIG. 2) is supplied from the constant current circuit 5 and a second current ( The output is controlled by the second period during which I2) in FIG. 2 is supplied. The first period and the second period are not limited to one cycle time for reading from all the cells 1 arranged in the pixel sensor unit 2 in an array, and are shorter than one cycle time. It is only necessary to obtain outputs from several cells 1 and perform human detection and flame detection. Further, it may be an integral multiple of one cycle time.

  Specifically, detection is performed by alternately repeating the first period and the second period as shown in FIG. That is, in the first period, the current I1 is supplied to the sensor diode D to read out the signal. In the second period, the current I2 is supplied to the sensor diode D to read out the signal.

  The operation of the infrared sensor device configured as described above will be described. In the first period, the control unit 10 controls the constant current circuit 5 so as to supply the current I1 to the sensor diode D, gives a signal for driving one row by the driving circuit 4, and scans one column by the output scanning circuit 6. Thus, the output signal of the sensor diode D of the cell 1 whose row and column intersect is sent from the output scanning circuit 6 to the reading circuit 8. Further, the control unit 10 sequentially changes one column scanned by the output scanning circuit 6, whereby the output signals of the sensor diodes D of the cells 1 related to one row driven by the driving circuit 4 are sequentially output. If the time of the first period is further left, the output signals of the sensor diodes D of the cells 1 related to the next row driven by the drive circuit 4 are sequentially output in the same manner as described above.

  In the second period, the control unit 10 controls the constant current circuit 5 so as to supply the current I2 to the sensor diode D, the drive circuit 4 gives a signal for driving one row, and the output scanning circuit 6 scans one column. . The scanning by the drive circuit 4 and the output scanning circuit 6 is the same as in the first period, and the output signal of the sensor diode D designated by the driving circuit 4 and the output scanning circuit 6 is sent from the output scanning circuit 6 to the readout circuit 8. .

  The control unit 10 compares the output signal of the readout circuit 8 obtained in the first period and the second period with a predetermined threshold value, respectively, detects flame occurrence in the first period when exceeding the threshold value, The presence of a person is detected in the second period. In this embodiment, when the occurrence of flame is detected, it is locked only in the second period and the current I1 is supplied from the constant current circuit 5 to the sensor diode D to continue the flame detection.

  In the case of flame detection, an alarm generator (not shown) can be driven to generate an alarm. In addition, based on the output signal of the readout circuit 8, each is compared with a predetermined threshold value. When the threshold value is exceeded, the process of detecting the occurrence of flame in the first period and detecting the presence of a person in the second period is signal processing. The control unit 10 may obtain the result and perform the period lock control.

The block diagram which shows the Example of the infrared sensor apparatus which concerns on this invention. The figure which shows the temperature dependence of the IV characteristic of the infrared sensor apparatus which concerns on this invention. The figure which shows the drive method of the Example of the infrared sensor apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cell 2 Pixel sensor part 3 Signal line 4 Drive circuit 5 Constant current circuit 6 Output scanning circuit 7 Signal line 8 Reading circuit 10 Control part 20 Signal processing part D Sensor diode

Claims (4)

A sensor diode for detecting infrared;
A constant current circuit for supplying currents having different current values to the sensor diode;
A control unit for controlling a current value supplied from the constant current circuit to the sensor diode;
In an infrared sensor device comprising:
The control unit performs output control in a first period in which the first current is supplied from the constant current circuit and in a second period in which the second current larger than the first current is supplied. Sensor device. The infrared sensor device according to claim 1, wherein the control unit performs output control by alternately repeating the first period and the second period. The infrared sensor device according to claim 1, wherein when the output of the sensor diode in the first period is equal to or greater than a predetermined value, the infrared sensor device is locked only in the first period or the second period. The control unit executes a human body detection mode for detecting a human body in the first period, and executes a fire detection mode for detecting a fire in the second period. Infrared sensor device.

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