JPH01113624A - Structure of pyroelectric sensor apparatus - Google Patents

Abstract

PURPOSE:To reduce a cost, by providing a reflecting part for expanding the detecting range, so that incident infrared rays are reflected from reflecting surfaces, which are vertically provided at the edge parts of a window in the opening direction of the window in the case of the main body of a sensor. CONSTITUTION:Vertical pieces 17 of a reflecting member 6 are arrange at the outsides of the edge pars of both sides of a window 2 of a case cover 3a so that the opening direction of the window 2 and the direction of reflecting surfaces 5 are the same. A filter 13, whose area is smaller than a conventional filter, is used. The size of the window 2 of the case cover 3a is made smaller in correspondence with the size of the filter 13. Light from the side part is inputted through an opening 16 of the reflecting member 6 and reflected from the reflecting surfaces 5 of the vertical pieces 17 of the reflecting member 6. The direction of the light is changed. The light passes through the filter 13. Even if the area of the filter 13 is made small at this time, the light is reflected from the reflecting surfaces 5 of the reflecting member 6. Therefore, the detecting range is expanded. Since the area of the costly filter is made small, the cost can be lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field 1] The present invention relates to the structure of a pyroelectric element sensor using a pyroelectric element that senses infrared rays emitted from a human body and detects a person.

[Background Art 1] FIG. 4 is a cross-sectional view of a conventional sensor body 4 of this type using a pyroelectric element that senses infrared rays generated by a human body and detects a person.

In this example, two pyroelectric elements 1 for detecting infrared rays are arranged in parallel on the upper surface of the substrate 7, and a semiconductor element 8 made of, for example, an FET, which outputs the output of the pyroelectric elements 1, is arranged on the lower surface of the substrate 7. be. The upper ends of lead terminals 9, 10, 11 are soldered and fixed to the board 7, and the lower parts of the lead terminals 9, 10, 11 protrude from an insertion hole 12 formed in the case body 3a. The pyroelectric element 1 is covered by a cylindrical case cover 3b, and a detection opening window 2 is opened in a portion of the case cover 3b on the detection surface side of the pyroelectric element 1.

A filter 13 is disposed on the lower surface of the open window 2, and this filter 13 is adhered to the peripheral edge of the lower surface of the open window 2 of the case cover 3b with an adhesive 14. still,
A case 3 is composed of a case cover 3b and a case body 3a.

Figure 5 shows a circuit diagram when two pyroelectric elements 1 are used,
Further, FIG. 6 shows an arrangement diagram of the pyroelectric element 1. As shown in FIG.

When the pyroelectric element 1 is irradiated with infrared rays, the pyroelectric element 1 generates a voltage to drive the semiconductor element 8 and output a detection signal. Here, the pyroelectric element 1 uses a ceramic type or a pyroelectric film, but the filter 13, which is a bandpass filter that transmits only the infrared region corresponding to the heat emitted by humans, is expensive. Yes, the cost is greatly influenced by the area. If the area of the filter 13 is made small, the detection range will be limited to only the area in front of the pyroelectric element 1, as described later, and when trying to scan a wide space,
A large number of devices are required, and the total cost will not be reduced.

FIG. 7 shows the detection range in the X direction by the pyroelectric element 1 shown in FIG. Here, the reason why the distance L (FIG. 4) between the aperture window 2 and the pyroelectric element 1 is set constant is as follows. That is, by narrowing this distance and bringing the pyroelectric element 1 and the aperture window 2 closer together, the disturbance light is filtered through the filter 13.
This is because the heat received by the case cover 3b is easily transmitted to the pyroelectric element 1, and malfunctions are likely to occur. Now, in FIG. 7, the line connecting the edge of the aperture window 2 and the pyroelectric element 1 extends at θ with respect to the normal to the aperture surface of the aperture window 2. Further, FIG. 8 shows the detection range in the X direction shown in FIG. 6, which extends θy from the opening window 2. Furthermore, as shown in FIG. 9, if the filter 13 is made smaller, the diagonal spread is eliminated;
The detection range becomes smaller.

[Objective of the Invention 1] The present invention has been provided in view of the above-mentioned points, and it is an object of the present invention to provide a structure of a pyroelectric sensor device that reduces the cost without narrowing the detection range. This is the purpose.

[Disclosure 1 (Structure)] The present invention comprises a filter that transmits an infrared region, a pyroelectric element that detects infrared rays through an infrared filter, and an aperture window provided on the detection surface side of the pyroelectric element. The sensor body is formed by a case that covers the electronic element and filter, and the detection range is expanded by reflecting incoming infrared rays by a reflective surface installed at the edge of the aperture window in the direction of the aperture window of the sensor body case. By providing a reflective member, incoming infrared rays are reflected by the reflective surface of the reflective member, and a filter with a small area can be used without narrowing the detection range. It is something.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

Incidentally, the constituent members of the sensor main body 4 are almost the same as those of the conventional example. As shown in FIG. 1, the sensor body 4 has lead terminals 9, 10, 11 protruding from the case 3 fixed to a substrate 15 by soldering or the like. Further, a reflecting member 6 is provided so as to cover the entire sensor body 4, and the lower end of this reflecting member 6 is similarly fixed to the substrate 15 by soldering or the like. The reflective member 6 made of a metal fitting has a substantially U-shaped folded surface, and as shown in FIGS.
6 is formed. At the same time as this opening 16 is formed, in other words, in order to form the opening 16, the vertical pieces 17, 17 are cut and raised from both sides and are hung vertically. The inner surface of this vertical piece 17 is used as a reflecting surface 5, and the light entering from the opening 16 of the reflecting member 6 is reflected by the reflecting surface 5, and the infrared rays are made to enter the pyroelectric element 1 via the filter 13. There is. Reflective member 6
is coated with gloss such as nickel plating to increase reflection efficiency.
It has been treated with plating. The reflecting member 6 is fixed to the substrate 15 by inserting the lower end mounting piece 6b into the mounting hole 19 of the board 15 and soldering, etc.
9 is formed integrally with the mounting hole 18 through which the lead terminal 9, 10, 11 of the sensor body 4 is inserted, and is punched out using a mold, so there is relatively no variation and optical positional deviation does not occur.

The vertical piece 17 of the reflecting member 6 is connected to the opening window 2 of the case cover 3a.
The hanging pieces 17 are arranged slightly outside the edges on both sides of the window so that the opening direction of the opening window 2 and the reflective surface 5 are in the same direction. Here, the filter 13 has a smaller area than before, and the opening window 2 of the case cover 3a is
The size of the filter 13 is also small corresponding to the size of the filter 13.

The light from the side enters through the opening 16 of the reflective member 6, is reflected by the reflective surface 5 of the vertical piece 17 of the reflective member 6, changes direction, and passes through the filter 13. do. The filter 13 transmits only infrared rays, and the pyroelectric element 1 detects the infrared rays. In this case, even if the area of the filter 13 is made small, the light will not reach the reflective surface 5 of the reflective member 6.
Therefore, θX, which indicates the expansion of the detection range, becomes large, and even if the area of the filter 13 is made smaller than before, the detection range can be the same or expanded. Furthermore, since the area of the filter 13, which has the highest cost, is reduced, the cost can be reduced. Furthermore, the filter 13 used in Fig. 1 is! Although it is the same size as the filter 13 used in Figure 9, the detection range is the same as that of the large filter 13 used in Figures 7, etc., the number of sensor bodies 4 installed is also the same, and the area By using a filter 13 or the like with a small value, it is possible to reduce costs. Also, of course, by using the reflective member 6, the detection range can be wider than when using the pyroelectric element 1 alone.

In addition, in FIG. 1, the hanging piece 17 of the reflecting member 6 is perpendicular to the surface of the case cover 3b, but if the hanging piece 17 is further bent inward as shown in FIG. Since the reflection angle is widened, the detection range can be further expanded.

[Effect of the Invention 1 As described above, the present invention includes a filter that transmits infrared light, a pyroelectric element that detects infrared light that passes through the filter,
An opening window is provided on the detection surface side of the pyroelectric element, and a case covering the pyroelectric element and the filter forms a sensor body, and the sensor body is erected at the edge of the opening window in the opening direction of the opening window of the case of the sensor body. Since it is equipped with a reflective member that reflects incoming infrared rays with a reflective surface and widens the detection range, even a filter with a small area can narrow the detection range by reflecting incoming infrared rays with the reflective surface of the reflective member. without doing,
A filter with a small area can be used, so
If the detection range is the same as before, a filter with a smaller area can be used, and by reducing the area of the filter that has the highest cost for passing through the infrared region, it is possible to reduce costs. .

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an embodiment of the present invention, Fig. 2 is an exploded perspective view of the same as above, Fig. 3 is a side view of main parts of another embodiment of the same as above, and Fig. 4 is a sectional view of an embodiment of the present invention.
FIG. 5 is a circuit diagram of the sensor body, FIG. 6 is a layout diagram of a pyroelectric element, and FIGS. 7 to 9 are explanatory diagrams of the operation of the conventional example. 1 is a pyroelectric element, 2 is an opening window, 3 is a case, 4 is a sensor body, 5 is a reflective surface, 6 is a reflective member, and 13 is a filter. Agent Patent Attorney Ishi 1) Ai Shichi

Claims (1)

[Claims] (1) A filter that transmits infrared light, a pyroelectric element that detects infrared light that passes through the filter, and a case that covers the pyroelectric element and filter by providing an opening window on the detection surface side of the pyroelectric element. A pyroelectric element that forms the sensor body and is provided with a reflective member that expands the detection range by reflecting incoming infrared rays by a reflective surface installed at the edge of the aperture window in the opening direction of the aperture window of the sensor body case. Structure of the sensor device.