JP3207628B2 - Pyroelectric infrared sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pyroelectric infrared sensor belonging to a thermal type sensor utilizing a temperature change due to absorption of infrared rays among infrared sensors for detecting a human body or the like.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for performing security and air conditioning control by detecting the presence or absence and the amount of activity in a room. In other words, a human body is detected by detecting infrared rays emitted from the human body, and infrared signals are generated using an infrared sensor for the purpose of using the signals for controlling environmental control devices such as air conditioners and lighting equipment and security systems. Source detecting devices have been used. Two types of infrared sensors are known: a quantum sensor that captures infrared light as a photon, and a thermal sensor that uses a change in the physical properties of an element resulting from an increase in the temperature of the element due to absorption of infrared light. Is generally required to be cooled with liquid nitrogen, etc., and is expensive and complicated in handling. Therefore, the latter thermal sensor is generally used. Among thermal sensors, a pyroelectric infrared sensor is particularly suitable for detecting an infrared source because it has higher sensitivity than other infrared sensors. Since this pyroelectric infrared sensor basically detects a change in infrared light, if an attempt is made to detect a stationary infrared light source, the infrared light intermittently enters the sensor light receiving unit by any method. In general, intermittent incidence (chopping) of infrared rays is realized by rotating or vibrating a chopper such as a disk with a slit or a flat plate.

FIG. 8 is a schematic view showing an electrode pattern of a pyroelectric element of a conventional pyroelectric infrared sensor.
Shows the front side of the pyroelectric substrate, and FIG. 4B shows the back side of the pyroelectric substrate. In the pyroelectric infrared sensor of FIG.
A light receiving electrode 72 for receiving infrared rays and a compensating electrode 74 corresponding to each of the light receiving electrodes 72 are formed on the surface 71 of the pyroelectric substrate.
A counter electrode 77 is formed on 6 corresponding to the light receiving electrode 72 and the compensation electrode 74. Pyroelectric substrate surface 7
Irradiation of only one light receiving electrode 72 with an infrared ray causes a potential difference. By detecting the voltage, an infrared ray source can be detected.

[0004]

In the pyroelectric infrared sensor for detecting infrared rays in this manner, it is particularly important that sensing is always performed completely accurately. In other words, if the sensor cannot be used due to deterioration of the pyroelectric body used for the sensor or failure of the sensor itself during the use of the sensor, a serious problem occurs and the sensor must be replaced immediately. There are things you have to do. In such a case, a time loss occurs, and there is a problem in security and safety. Therefore, it is necessary to constantly check the operation state of the sensor, quickly check for deterioration and failure, and quickly replace the sensor. In other words, the sensor's self-diagnosis function always checks for deterioration and failure of the sensor, confirms that sensing is always performed correctly, and if it is not performed, detects it immediately. It is necessary.

However, since the conventional pyroelectric infrared sensor does not have such a self-diagnosis function, there is a problem that it is not possible to check for the occurrence of deterioration or failure and to replace the sensor periodically.

[0006] Further, even if it exists, its structure is complicated.

The present invention has been made in consideration of the above-described problems of the conventional pyroelectric infrared sensor, and provides a pyroelectric infrared sensor provided with a self-diagnosis function for confirming that accurate sensing is always possible. It is intended to provide.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a pyroelectric substrate.
A light-receiving electrode portion that is arranged on one surface and receives infrared light,
It is arranged on the one surface of the pyroelectric substrate, and
A corresponding compensation electrode section, and the light receiving electrode section and the compensation
The pyroelectric substrate is opposed to each of the arrangement positions of the electrode portions.
Element having respective opposite electrode portions arranged on the opposite surface of the pyroelectric element
A predetermined value for diagnosing the operation state of the pyroelectric element.
Heating means heated to a temperature, wherein the compensation electrode portion or
Is a part of the counter electrode part also serving as the heating means.
A pyroelectric infrared sensor .

[0009] Further , the present invention provides the above-described pyroelectric element with infrared rays.
Focusing means for focusing, and infrared rays incident on the pyroelectric element
Use chopping means that can be intermittently interrupted.
And between the pyroelectric element and the light collecting means, or
Infrared onset between the focusing means and the chopping hand stage
The pyroelectric red, wherein an optical element is provided.
It is an outside line sensor.

[0010]

According to the present invention, the heating means controls the operation state of the pyroelectric element.
For diagnosis, it is heated to a predetermined temperature and emits infrared rays.
The infrared light is input to the pyroelectric element. Thereby pyroelectric
The deterioration of the element can be determined.

Further, according to the present invention, the infrared light emitting element is preferably a pyroelectric element.
Infrared light is input to the pyroelectric element to diagnose the operating condition of the
Shoot.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing embodiments thereof.

Embodiment 1 FIG. 1 is a schematic view showing an electrode pattern of a pyroelectric element of a pyroelectric infrared sensor according to a first embodiment of the present invention, and FIG. FIG. 3B shows the electric circuit board surface side, and FIG.
Indicates the back side of the pyroelectric substrate. That is, a light-receiving electrode 32 for receiving infrared rays and a compensation electrode 34 corresponding to the light-receiving electrode 32 are formed on a pyroelectric substrate surface 31 of the pyroelectric infrared sensor, respectively. Back 3
A counter electrode 37 facing the light receiving electrode 32 and the compensation electrode 34 is formed on 6. The compensating electrode 34 is in the form of a single plate, and two compensating electrode leads 35 are attached to both ends of the compensating electrode 34. The compensating electrode 34 constitutes a heater of a heating means. ing.
The light receiving electrode 32 is connected to a light receiving electrode lead 33.

Next, the operation principle of the pyroelectric infrared sensor according to the first embodiment will be described.

First, by applying a predetermined constant voltage between the compensating electrode leads, a current flows through the compensating electrode 34 to raise the temperature to a predetermined constant value. Then, a certain amount of infrared rays is emitted from the compensation electrode 34 whose temperature has risen, and the emitted infrared rays can be detected by the adjacent light receiving electrode 32. If this is performed regularly, the operating state of the sensor can be determined to be normal while the detection amount is constant,
When the amount of detection decreases, it can be determined that the sensor has deteriorated or failed. Therefore, by replacing the sensor when the detection amount decreases, it is possible to prevent a problem caused by the use of the defective sensor.

FIG. 2 is a circuit diagram for explaining an electric circuit in the pyroelectric infrared sensor according to the first embodiment. In FIG. 2, by connecting a compensator 42 and applying a certain voltage to the compensator, the compensator 42 is used as a heat source to generate infrared rays from the compensator 42. When the detection is performed and the detected amount changes, it is determined that the sensor has deteriorated or failed.

As described above, the compensation electrode 34 is used as a heater wire to periodically emit a certain amount of infrared rays.
By detecting this by the light receiving electrode 32, the performance of the sensor itself can be easily determined. Furthermore, since the electrode is used as a heater wire as it is, it can be made compact and inexpensive, and has high reliability and can perform self-diagnosis with high accuracy.

As described above, according to the present embodiment, by forming two leads 35 on the compensation electrode 34 and applying a voltage between them, the compensation electrode 34 can be used as a heater wire. In addition, a pyroelectric infrared sensor capable of performing self-diagnosis with high accuracy and high reliability can be obtained.

(Embodiment 2) FIG. 3 is a schematic view of an electrode pattern of a pyroelectric element of a pyroelectric infrared sensor according to a second embodiment of the present invention, and FIG. FIG. 4B shows the front side of the body substrate.
Indicates the back side of the pyroelectric substrate. The pyroelectric infrared sensor of the present embodiment is different from the pyroelectric infrared sensor of the first embodiment in that the compensation electrode 34 on the pyroelectric substrate surface 31 is formed corresponding to the light receiving electrode 32, On the other hand, of the opposing electrodes 37 provided on the pyroelectric substrate back surface 36 so as to oppose the light receiving electrode 32 and the compensating electrode 34, the opposing electrode 37 opposing the compensating electrode 34 is formed in one plate shape. Counter electrode 37
And two opposite electrode lead portions 38 are attached to both ends of the heater, and the opposite electrode 37 constitutes a heater of a heating means.

The operation principle of this embodiment is basically the same as that of the first embodiment. That is, by applying a predetermined constant voltage between the opposing electrode lead portions, the opposing electrode 37 is applied.
Current to raise the temperature to a predetermined constant value. Then, a certain amount of infrared rays is emitted from the counter electrode 37 whose temperature has risen, and the emitted infrared rays are
2 can be detected. If this operation is performed regularly, it can be determined that the sensor is operating normally while the detected amount is constant, and it can be determined that the sensor has deteriorated or failed when the detected amount has decreased. Therefore, by replacing the sensor when the detection amount decreases, it is possible to prevent a problem caused by the use of the defective sensor.

As described above, the counter electrode 37 is used as a heater wire, and a certain amount of infrared rays is periodically emitted.
By detecting this by the light receiving electrode 32, the performance of the sensor itself can be easily determined. Furthermore, since the electrode is used as a heater wire as it is, it can be made compact and inexpensive, and has high reliability and can perform self-diagnosis with high accuracy.

As described above, according to the present embodiment, two lead portions 38 are formed on the counter electrode 37, and a voltage is applied between them, so that the counter electrode 37 can be used as a heater wire. In addition, a pyroelectric infrared sensor capable of performing self-diagnosis with high accuracy and high reliability can be obtained.

In the above embodiment, the counter electrode facing the compensation electrode is used as the heater wire. Alternatively, the counter electrode facing the light receiving electrode may be formed as a single plate.
It may be used as a heater wire.

Reference Example 1 FIG. 4 is a schematic view of an electrode pattern of a pyroelectric element of a pyroelectric infrared sensor according to a first reference example related to the present invention, and FIG. FIG. 3B shows the electric circuit board surface side, and FIG.
Indicates the back side of the pyroelectric substrate. The pyroelectric infrared sensor of the present embodiment is different from the pyroelectric infrared sensors of the first and second embodiments in that the light receiving electrode 22 formed on the pyroelectric substrate surface 21 and the light receiving electrode The point is that the heater wiring 24 is formed between the compensating electrodes 25 corresponding to 22. In addition, on the back surface 27 of the pyroelectric substrate, a counter electrode 28 facing the light receiving electrode 22 and the compensation electrode 25 is formed as in the first embodiment.

In this embodiment, a current is applied by applying a predetermined constant voltage to the heater wiring 24 provided on the pyroelectric substrate surface 21 to raise the temperature to a predetermined constant value. Then, a certain amount of infrared rays is emitted from the heater wiring 24 whose temperature has risen, and the emitted infrared rays can be detected by the light receiving electrode 22. If this operation is performed regularly, it can be determined that the sensor is operating normally while the detected amount is constant, and it can be determined that the sensor has deteriorated or failed when the detected amount has decreased. Therefore, by replacing the sensor when the detection amount decreases, it is possible to prevent a problem caused by the use of the defective sensor.

As described above, the heater wiring 24 is formed in the vicinity of the light receiving electrode 22, a voltage is applied periodically, the temperature is raised, a certain amount of infrared rays is emitted, and this is detected by the light receiving electrode 22. Thus, the performance of the sensor itself can be easily determined. Further, since only the heater wiring 24 needs to be formed, it can be manufactured compactly and inexpensively, and the self-diagnosis can be performed with high reliability and high accuracy.

As described above , according to the present embodiment, the pyroelectric type can be easily and highly accurately and reliably diagnosed only by forming the heater wiring near the light receiving electrode on the substrate surface. An infrared sensor can be obtained.

(Embodiment 2) FIG. 5 is a schematic view of an electrode pattern of a pyroelectric element of a pyroelectric infrared sensor according to a second embodiment of the present invention, and FIG. FIG. 3B shows the electric circuit board surface side, and FIG.
Indicates the back side of the pyroelectric substrate. This example is the first reference
The difference from the example is that the heater wiring 68 is formed near the counter electrode 67 on the back surface 66 of the pyroelectric substrate.
The light receiving electrode 62 and the compensation electrode 64 formed on the pyroelectric substrate front surface 61 and the counter electrode 67 formed on the pyroelectric substrate back surface 66 are the same as those of the conventional pyroelectric substrate.

In this embodiment, a current is applied to the heater wiring 68 provided on the back surface 66 of the pyroelectric substrate by applying a predetermined voltage to raise the temperature to a predetermined value. Then, a certain amount of infrared rays is emitted from the heater wiring 68 whose temperature has risen, and the emitted infrared rays can be detected by the light receiving electrode 62. If this operation is performed regularly, it can be determined that the sensor is operating normally while the detected amount is constant, and it can be determined that the sensor has deteriorated or failed when the detected amount has decreased. Therefore, by replacing the sensor when the detection amount decreases, it is possible to prevent a problem caused by the use of the defective sensor.

As described above, the heater wiring 68 is formed in the vicinity of the counter electrode 67, a voltage is applied periodically, the temperature is raised, a certain amount of infrared rays is emitted, and this is detected by the light receiving electrode 62. Thus, the performance of the sensor itself can be easily determined. Further, since only the heater wiring 68 needs to be formed, the heater can be made compact and inexpensive, and the self-diagnosis can be performed with high reliability and high accuracy.

As described above, according to the present embodiment , the pyroelectric type can be easily and highly accurately and reliably diagnosed only by forming the heater wiring near the counter electrode on the back surface of the substrate. An infrared sensor can be obtained.

( Embodiment 3 ) FIG. 6 is a schematic structural view of a pyroelectric infrared sensor according to a third embodiment of the present invention. That is, the pyroelectric infrared sensor according to the present embodiment forms a pyroelectric element by forming an electrode pattern of an infrared array sensor in which a plurality of light receiving portions are provided in a matrix on the pyroelectric substrate 11. On the front, in order
An infrared light shielding plate 12, a mesh-like heater wire 13, and a silicon infrared transmission lens 14 for condensing infrared light on the pyroelectric element are provided only on the compensation electrode portion. And a chopper 15 for intermittently blocking infrared light incident on the infrared transmitting lens 14. The chopper 15 is, for example, mechanically connected to a stepping motor and can rotate.
The aforementioned infrared transmitting lens 14 is a condensing unit, and the chopper 15 is a chopping unit.

In this embodiment, a current is caused to flow by applying a predetermined constant voltage to the heater wire 13 provided on the front surface of the pyroelectric element, thereby raising the temperature to a certain constant value. Then, a certain amount of infrared rays is emitted from the heater wire 13 whose temperature has risen, and the emitted infrared rays can be detected by the light receiving electrode of the pyroelectric element. If this operation is performed regularly, it can be determined that the sensor is operating normally while the detected amount is constant, and it can be determined that the sensor has deteriorated or failed when the detected amount has decreased. Therefore, by replacing the sensor when the detection amount decreases,
Problems caused by the use of a defective sensor can be prevented beforehand.

As described above, the heater wire 13 is formed between the pyroelectric substrate 11 and the infrared transmitting lens 14, and a voltage is periodically applied to raise the temperature to emit a certain amount of infrared light. Is detected by the light receiving electrode, the performance of the sensor itself can be easily determined. further,
Since only the heater wire 13 needs to be attached, it can be made compact and inexpensive.
It has high reliability and can perform self-diagnosis with high accuracy.

As described above, according to the present embodiment, the heater wire 1 is provided between the pyroelectric substrate 11 and the infrared transmitting lens 14.
By merely providing 3, it is possible to easily obtain a pyroelectric infrared sensor capable of performing self-diagnosis with high accuracy and high reliability.

In the above embodiment, the heater wire 13 is attached between the pyroelectric substrate 11 and the infrared transmitting lens 14, but instead, it is attached between the infrared transmitting lens 14 and the chopper 15. Is also good.

Embodiment 4 FIG. 7 is a schematic structural view of a pyroelectric infrared sensor according to a fourth embodiment of the present invention. That is, in the pyroelectric infrared sensor of the present embodiment, a pyroelectric element 81 forming an infrared array sensor provided in a plurality of matrices is installed in a can structure 83, and A silicon window 82 is provided on the front surface. Further, an LED (light emitting diode) 8 is provided in the can structure 83 as a heat source.
4 is attached to an area other than the silicon window material 82. The LED 84 is an infrared light emitting element.

In this embodiment, the LED 8 for emitting infrared rays
4 is periodically turned on to emit a certain amount of infrared rays, and the emitted infrared rays are
Is detected by the light receiving electrode. If this operation is performed regularly, it can be determined that the sensor is operating normally while the detected amount is constant, and it can be determined that the sensor has deteriorated or failed when the detected amount has decreased. Therefore, by replacing the sensor when the detection amount decreases, it is possible to prevent a problem caused by the use of the defective sensor.

As described above, the heat source such as the LED 84 is mounted in the can structure 83 containing the pyroelectric element 81,
By periodically turning on the light, emitting a certain amount of infrared rays, and detecting this with a light receiving electrode, the performance of the sensor itself can be easily determined. Further, the LED 84
Since only a single unit needs to be attached, it can be made compact and inexpensive, and has high reliability.
Self-diagnosis can be performed with high accuracy.

As described above, according to the present embodiment, the self-diagnosis can be easily performed with high accuracy and high reliability by mounting the heat source in the can structure 83 containing the pyroelectric element 81. Thus, a pyroelectric infrared sensor can be obtained.

As described above, the pyroelectric infrared sensor capable of self-diagnosis makes it possible to easily and immediately check the deterioration state or failure of the sensor. By using the electrodes as heater wires capable of emitting a certain amount of infrared rays, it is possible to easily and accurately determine the deterioration state or failure of the sensor with high reliability. Also, by forming a heater wiring that emits a certain amount of infrared rays near the light receiving section, the state of the sensor can be monitored similarly. Furthermore, by forming such a heater wiring, the life of the sensor can be determined, and the sensor can be replaced when the life has expired, so that the cost can be reduced. Further, since the defective state of the sensor can be immediately grasped, the problem caused by the use of the defective sensor can be solved, and the security and safety can be greatly improved. As described above, the structure is very simple, and accurate and highly reliable self-diagnosis can be easily performed at low cost by using this pyroelectric infrared sensor. Therefore, by using the present invention, it is possible to greatly contribute to the manufacture of a pyroelectric infrared sensor to which a self-diagnosis with high reliability and safety is easily and accurately provided.

In each of the above embodiments, the heating means is constituted only by the heater, and the heating control section for performing the periodic heating is separately provided. However, the heating control section may be replaced by the heater. It may be provided together with.

[0043]

As is apparent from the above description, the present invention provides a method for diagnosing the operation state of a pyroelectric element, in which
Partly serves as heating means, so the structure is extremely simple
This has the advantage that a self-diagnosis function for confirming that sensing can be performed accurately can be provided.

[Brief description of the drawings]

FIGS. 1A and 1B are schematic views showing an electrode pattern of a pyroelectric element of a pyroelectric infrared sensor according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram for explaining an electric circuit of the pyroelectric infrared sensor according to the first embodiment of the present invention.

FIGS. 3A and 3B are schematic diagrams showing an electrode pattern of a pyroelectric element of a pyroelectric infrared sensor according to a second embodiment of the present invention.

FIGS. 4A and 4B show a first embodiment related to the present invention; FIGS.
It is the schematic which shows the electrode pattern of the pyroelectric element of the pyroelectric infrared sensor of the reference example of FIG.

FIGS. 5A and 5B show a second embodiment related to the present invention .
It is the schematic which shows the electrode pattern of the pyroelectric element of the pyroelectric infrared sensor of the reference example of FIG.

FIG. 6 is a schematic configuration diagram of a pyroelectric infrared sensor according to a third embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of a pyroelectric infrared sensor according to a fourth embodiment of the present invention.

FIGS. 8A and 8B are schematic views showing electrode patterns of a pyroelectric element of a conventional pyroelectric infrared sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Pyroelectric substrate 12 Infrared shielding plate 13 Heater wire 14 Infrared transmission lens 15 Chopper 22, 32, 62 Light receiving electrode 24, 68 Heater wiring 25, 34, 64 Compensation electrode 28, 37, 67 Counter electrode 40 Pyroelectric body 41 Light receiving Unit 42 compensating unit 43 facing unit 44 amplifier circuit 84 LED

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01J 1/02 G01J 1/42-1/44 G01J 5/02 G01J 5/12-5/14 G01V 9 / 04 H01L 37/00-37/02 G08B 13/19-13/191

Claims (2)

(57) [Claims] An infrared light source is disposed on one surface of a pyroelectric substrate and emits infrared light.
A light receiving electrode portion for receiving light, and a light receiving electrode portion disposed on the one surface of the pyroelectric substrate;
Placed, a compensation electrode portion corresponding to the light receiving electrode portion, and
At the positions of the light receiving electrode section and the compensation electrode section, respectively.
Opposing, each opposing disposed on the opposite surface of the pyroelectric substrate
A pyroelectric element having an electrode portion; and a predetermined temperature for diagnosing an operation state of the pyroelectric element.
Heating means to be heated to a part of the compensation electrode portion or the counter electrode portion
A pyroelectric infrared sensor, which also serves as a heating means.
Sensor . 2. A focusing means for focusing infrared rays on said pyroelectric element.
And intermittently intercept infrared rays incident on the pyroelectric element.
Further comprising a chopping means capable of detecting a difference between the pyroelectric element and the light condensing means or the light condensing means.
An infrared light emitting element is provided between the step and the chopping means.
2. The pyroelectric red according to claim 1, wherein
Outside line sensor.