JPH0736306Y2 - Object detection device - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an object detection device used in a crime prevention device, an automatic door sensor or the like.

[Conventional technology]

Conventionally, such an object detecting device is configured, for example, as shown in FIG. That is, the object detection device 1 includes a pyroelectric detection element 3 fixedly arranged in the case 2, a lens 4 attached so as to close the opening 2a of the case 2, and the inside of the case 2. And a control circuit 5 for processing signals from the pyroelectric detection element 3 mounted on a substrate or the like behind the pyroelectric detection element 3 and performing an appropriate detection operation. A lens 4 is provided so that the position where the pyroelectric type detection element 3 is disposed is in focus.

According to the object detection device 1 having such a configuration, when the light to be detected enters the pyroelectric detection element 3 through the lens 4, the detection element 3 detects the energy change of the incident light and outputs a signal. A desired detection operation, that is, sounding of an alarm sound, opening and closing of a door, etc., is performed by outputting and outputting the output signal as appropriate by the control circuit 5.

[Problems to be solved by the device]

However, in the object detecting device 1 configured as described above, as shown in FIG. 3A, the object detecting device 1 according to the present invention is based on the size of the light receiving surface of the detecting element 3 and the focal length f of the lens 4. The detection range of the
The detection area S at the detection position is determined according to the distance d from the detection position to the detection position. Since the detection area S is proportional to the square of the distance d, the distance d to the detection position becomes large, for example, 2 If the doubled 2d, the detection area S'is 4
That is, the detection sensitivity of the object detection device 1 at the detection position decreases in inverse proportion to the square of the distance.

Therefore, in order to keep the detection area S at the above-mentioned detection position constant even when the distance d to the detection position is increased, it is usual to use the lens 4'having different focal lengths f '. , The same detection area S is obtained from the object detection device 1 at a desired distance d ′. In this case, since the lens 4 ′ is arranged at the same position as the lens 4 with respect to the case 2, Since the distance f from the lens 4'to the detecting element 3 does not change, the detecting element 3 is displaced from the focal position of the lens 4 ',
The desired detection area S and detection sensitivity cannot be obtained.

Therefore, when replacing the lens 4 with a lens having a different focal length, it is necessary to replace the case 2 with a case formed to match the focal length of the lens used. Therefore, in response to various detection distances or detection sensitivities, prepare the optimum lens and case,
A mounting adapter must be prepared for each optical system, and since it is not very versatile, mass production effects cannot be obtained, which is a problem in terms of manufacturing cost.

The present invention has been made in view of the above points, and an object thereof is to provide an object detection device in which a mounting position of a detection element can be adjusted in the same case for lenses having various focal lengths.

[Means for Solving the Problems]

The above object includes, according to the present invention, a passive sensing element having a sensitivity characteristic to incident light to be detected, and an optical system arranged so that a focus is aligned with the passive sensing element. When the light to be detected from the outside enters the detection element through the optical system, the detection element outputs a signal to perform the detection operation. And a slide portion that is disposed adjacent to the opening on the front side of the case and is slidably supported in the case along the optical axis direction of the optical system from the open end on the rear side of the case to the opening on the front side. , The detection element is fixedly attached near the front edge of the slide part, and the detection element is positioned at the focal position in response to replacement with an optical system having a different focal length, and preferably the slide part is open on the front side. Hollow A riding section is preferably achieved by the control circuit for sensing operation based on the signal output from the sensing device and configured to provide in the sliding portion.

[Action]

According to this invention, since the detection element is arranged in the slide portion slidably supported in the case along the optical axis direction of the optical system, this slide portion is moved in the case in the optical axis direction. By moving, the sensing element can be adjusted in the optical axis direction so as to be brought to the focal position of the optical system corresponding to the focal length of the optical system attached to the case. .

Therefore, the optical system with various focal lengths is arranged adjacent to the opening of the case, and the slide unit is provided with the optical axis of the optical system in the case so that the detection element is located at the focal position of the optical system. By moving along the direction, select an optical system with an appropriate focal length, move the slide part according to the focal length of the optical system, and move it at a detection position that is a desired distance away from the object detection device. The desired detection sensitivity can be obtained. Therefore, by preparing only one type of case, it is possible to correspond to an optical system with an arbitrary focal length, and a case or mounting adapter individually formed for an optical system with various focal lengths. It is not necessary to prepare the above, and the cost can be reduced by mass production.

Further, when the control circuit is provided in the slide portion, the detection element and the control circuit can be configured integrally with each other, for example, by mounting them on the same substrate, so that the cost can be further reduced. Becomes

〔Example〕

Hereinafter, the present invention will be described in detail with reference to an embodiment shown in the drawings.

FIG. 1 shows an embodiment of an object detecting device according to the present invention.

The object detecting device 10 is a hollow slide portion 12 having an open front side that is inserted into a case 11 that is open at the front and rear sides so as to be slidable in the front and rear direction from the open end on the rear side. A pyroelectric sensing element 13 fixedly attached near the front edge of the slide portion 12, and inside the slide portion 12 behind the pyroelectric sensing element 13 mounted on a substrate or the like. A control circuit 14 for processing a signal from the pyroelectric type detection element 13 to perform an appropriate detection operation, and this case 11 so as to close an opening 11a which is an open end on the front side of the case 11.
And a lens 15 attached to the.

The optical axis of the lens 15 extends in the front-rear direction of the case 11, so that the slide portion 12 can slide along the optical axis of the lens 15.

The pyroelectric detection element 13 may be mounted on a substrate or the like that constitutes the control circuit 14, and in this case, the pyroelectric detection element 13 and the control circuit 14 are assembled in the slide portion 12. It will be easier to attach.

The object detecting apparatus 10 according to the present invention is configured as described above, and operates in the same manner as the case of the conventional object detecting apparatus 1 shown in FIG. That is, when the light to be detected enters the pyroelectric detection element 13 through the lens 15, the detection element 13 detects the energy change of the incident light and outputs a signal, and this output signal is appropriately output by the control circuit 14. By performing the processing described above, a desired detection operation, for example, sounding an alarm sound, opening and closing a door, and the like are performed.

Here, when a lens having a focal length different from the focal length of the lens 15 is used when assembling the object detecting apparatus 10, after assembling the object detecting apparatus 10 as shown in FIG. By moving the slide portion 12 with respect to the case 11 in the front-rear direction, that is, along the optical axis direction of the lens 15 (the direction of the arrow in FIG. 1), the pyroelectric detection element 13 attached to the slide portion 12 is moved. Can be brought to the focal position of the lens 15.

With this, using the case 11 and the slide portion 12,
It is possible to position the pyroelectric detection element 13 at the focal position of the lens 15 having an arbitrary focal length.

It should be noted that in the above embodiment, the lens 15 is used as the optical system.
However, it is clear that the same effect can be obtained by using a reflecting mirror such as a concave mirror instead of this lens.

[Advantage of Device] As described above, according to the present invention, the detecting element is arranged in the slide portion slidably supported in the case along the optical axis direction of the optical system. By moving the slide part in the optical axis direction in the case, the detection element is moved so that it is brought to the focal position of the optical system corresponding to the focal length of the optical system attached to the case. It can be adjusted axially. Therefore, an optical system with various focal lengths is arranged adjacent to the opening of the case, so that the detection element is located at the focal position of the optical system,
By moving the slide part in the case along the optical axis direction of the optical system, an optical system having an appropriate focal length is selected, and the slide part is moved in accordance with the focal length of the optical system. A desired detection sensitivity can be obtained at a detection position distant from the object detection device by a desired distance.

This makes it possible to support optical systems with arbitrary focal lengths by preparing only one type of case. It is not necessary to prepare a mounting adapter or the like, and the cost can be reduced by mass production.

Furthermore, when the control circuit is provided in the slide portion, the detection element and the control circuit can be configured integrally with each other, for example, by mounting them on the same substrate, so that the cost can be further reduced. It will be.

Thus, according to the present invention, since the mounting position of the sensing element can be adjusted in the same case for lenses having various focal lengths, the versatility is high and therefore mass production can be performed at low cost. An excellent object detection device will be provided.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of an object detecting device according to the present invention. FIG. 2 is a schematic sectional view showing an example of a conventional object detection device,
FIGS. 3A and 3B are explanatory views showing the detection state of the conventional object detection device. 10 …… Object detection device; 11 …… Case; 12 …… Slide part; 1
3 ... Pyroelectric sensing element; 14 ... Control circuit; 15 ... Lens.

Claims (2)

[Scope of utility model registration request] 1. An optical system comprising: a passive sensing element having a sensitivity characteristic to incident light to be detected; and an optical system arranged so that a focus thereof coincides with the passive sensing element. In an object detecting device configured to perform a detection operation by outputting a signal when the light to be detected enters the detection element through the system, the optical system has an opening on the front side of the case. And a slide part that is slidably supported in the case from the open end on the rear side of the case to the opening on the front side along the optical axis direction of the optical system. The detection element is fixedly attached near the front edge of the slide portion, and the detection element is positioned at the focal position corresponding to replacement with an optical system having a different focal length. The object detection device. 2. The slide section is a hollow slide section open on the front side, and a control circuit for performing a detection operation based on a signal output from the detection element is provided in the hollow slide section. The object detection device according to claim 1, wherein