JPS6130180Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a pyroelectric infrared sensor that can detect the movement of an object that emits infrared rays, such as a human body, including its direction, and attempts to reduce cost and space. It is something.

A conventional pyroelectric infrared sensor was constructed as shown in FIG.

That is, a field effect transistor 3 for impedance matching is arranged in the center of the upper surface of a base 2 having a plurality of terminals 1, and a support base 4 made of an insulator with a small diameter and low height is placed around the outer periphery of the field effect transistor 3. An insulating ring 5 with a large diameter and high height is arranged around the outer periphery of the stand 4, a reflecting plate 6 is arranged on this supporting stand 4, and conductive rings 7 and 8 are placed on the upper and lower outer periphery of the reflecting plate 6. A held pyroelectric film 9 is provided, a conductive ring 10 held on the upper surface of the insulating ring 5 is placed on top of this, and a window member 11 made of silicon or the like that transmits infrared rays is placed on top of this conductive ring 10. The entire structure was covered with a metal case 13 having a window hole 12 on the top surface.

With this configuration, an electric signal generated in the pyroelectric film 9 by infrared rays enters the gate of the field effect transistor 3 via the conductive ring 7 and the reflection plate 6, and the ground circuit is conductive. The case is grounded to the metal case 13 via the ring 8 and the conductive ring 10.

With this configuration, it is possible to detect the movement and proximity of an object that emits infrared rays, such as a human body, but it is not possible to detect the direction of movement.

Therefore, in order to detect the direction of movement, a pyroelectric infrared sensor 1 is required as shown in FIG.
The pyroelectric infrared sensors 14 and 15 are connected to the determination circuit 16, and if the moving direction of the object 17 is I, the pyroelectric infrared sensors 15
The voltage generated by the pyroelectric infrared sensor 14 is larger if the moving direction of the object 17 is higher, so by comparing the voltages generated by the pyroelectric infrared sensors 14 and 15, the direction can be detected. It will be possible.

In this way, conventional pyroelectric infrared sensors have two
It became impossible to detect the direction of an object's movement until it was used.

The present invention eliminates the above-mentioned drawbacks of the conventional technology, and aims to provide a device that can detect the direction of movement of an object with a single pyroelectric infrared sensor by adding only a few components. It is.

Embodiments of the present invention will be described below with reference to FIGS. 3 to 6.

First, in FIG. 3, reference numeral 18 is a base equipped with a plurality of terminals 19. Two field effect transistors 20 and 21 for impedance matching are built into the center of the upper surface of the base 18, and an insulator is placed around the outer periphery of the base. Further, an insulating ring 23 which is higher than the height of the support base 22 is arranged around the outer periphery of the support base 22.

A reflective plate 24 is disposed on the upper end surface of the support base 22, and on the upper surface of the reflective plate 24, two layers are laminated at a constant interval through a ring-shaped insulating spacer 25 and a conductive ring 26. Two pyroelectric films 27 and 28 are arranged, and a conductive ring 29 is coupled to the peripheral edge of the upper surface of the pyroelectric film 28.

Further, a conductive ring 30 that is electrically connected to the conductive ring 29 is arranged on the upper surface of the insulating ring 23, and a window member 31 made of silicon or the like that allows infrared rays to pass through is provided on the conductive ring 30.
All of these are covered with a metal case 33 having a window hole 32 on the top surface.

The two pyroelectric films 27 and 28 are connected to each electrode 3 as shown in FIGS. 4 and 5.
4 and 35 are provided at different positions so as not to overlap with each other, and the parts where the electrodes 34 and 35 are not provided are made transparent or a through hole is provided in the part corresponding to the other electrode to ensure that infrared rays are sufficiently emitted. The structure is such that it reaches the electrode.

Moreover, the electrodes 3 of the pyroelectric films 27 and 28
4 and 35 have lead wires 3 passing through the reflecting plate 24.
6, 37, the field effect transistor 20,
21, and the ground side is electrically connected to a metal case 33 via conductive rings 26, 29 and a conductive ring 30.

The electrical circuit diagram of this pyroelectric infrared sensor is shown in FIG.

With this configuration, the object that emits infrared rays is A in Figure 4.
When moving in the direction shown, the pyroelectric film 28
The generated voltage is larger in the pyroelectric film 27, and when it moves in the direction shown by B, the generated power is larger in the pyroelectric film 27.If the generated voltages of the pyroelectric films 27 and 28 are compared, the direction of movement can be determined. can be detected.
However, in this case, it is necessary to align the lines connecting the electrodes 34 and 35 parallel to the direction of movement.

Since the pyroelectric infrared sensor of the present invention is constructed as described above, it is possible to detect the moving direction of an object by using only two pyroelectric films, and it is possible to detect the moving direction of an object by using only two pyroelectric films. Compared to a device that requires the use of an infrared sensor, it is significantly advantageous in terms of cost and can be made smaller, requiring less space for installation, and has great practical value.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing a conventional pyroelectric infrared sensor, Figure 2 is an explanatory diagram of a method for detecting the moving direction of an object using the conventional pyroelectric infrared sensor, and Figure 3 is a cross-sectional view showing a conventional pyroelectric infrared sensor.
The figure is a sectional view showing an embodiment of the pyroelectric infrared sensor of the present invention, FIG. 4 is a top view of the pyroelectric film used in the sensor, and FIG. 5 is a sectional view of the pyroelectric film. FIG. 6 is an electrical circuit diagram of the sensor. 18... Base, 19... Terminal, 20, 21...
...Field-effect transistor, 22...Support stand, 2
3... Insulating ring, 24... Reflecting plate, 25... Insulating space, 26, 29... Conductive ring, 2
7, 28... Pyroelectric film, 30... Conductive ring, 31... Window member, 32... Window hole, 33
...Metal case, 34, 35... Electrode, 36,
37... Lead wire.

Claims (1)

[Scope of utility model registration request] A pyroelectric infrared sensor consists of a pyroelectric film and a reflector built into a metal case with an infrared-transmissive, airtight window member attached to the window hole on the top surface. The electrodes arranged on each pyroelectric film are arranged one above the other so that they do not overlap each other, and the part of the pyroelectric film where no electrode is formed is made transparent or the part corresponding to the other electrode is provided with a through hole. A pyroelectric infrared sensor having a configuration in which outputs are taken out independently from each of the pyroelectric films.