JP2000329860A - Infrared body detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent malfunction caused by stray light with a simple formation, by forming, as a rough surface, a part of a region disused in setting an effective domain in an optical system (lens body having plural lenses) arranged in front of a light-receiving surface of a sensor. SOLUTION: An optical system 4 is composed of a mirror 3 fitted to a sensor 1 having a cylindrical package 17, and a lens body 2 arranged in front of the mirror 3. The lens body 2 is formed by arranging five lenses 21 on the upper row of a dome part 22 and three lenses 21 on the lower row, and two lenses 21 on both end parts of the upper row are used in common respectively to four detecting beams C, C', D, D', and the other six lenses 21 are used for residual six detecting beams A, A', B, B'. And, front and back surfaces of the dome part 22 in the upper side periphery (shaded portion) of the lenses 21 on the upper row are formed as rough surfaces P, to scatter an infrared ray entering the part other than the lenses 21. Thus, incidence of unnecessary stray light into the sensor 1 can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared human body detector for detecting the presence or absence of a person in a predetermined detection area by detecting infrared radiation emitted from a human body.

[0002]

2. Description of the Related Art Generally, a human body detector of this type detects infrared rays radiated from a human body using an infrared sensor, and when the presence or absence of a person or the movement of a person is detected in a predetermined detection area, It is configured to control various loads such as a lighting load and a security alarm. As an infrared sensor, a pyroelectric infrared sensor that is a differential sensor is widely used. Since this type of infrared sensor cannot obtain an output when the rate of change of the amount of incident infrared light is small,
By arranging an optical system such as a lens body and a mirror on the path of the infrared light incident on the infrared sensor, the sensitivity unevenness is given in the field of view of the infrared sensor, and the light is incident on the infrared sensor even by a slight movement of a person in the field of view. The rate of change of the amount of infrared rays to be emitted is increased. Hereinafter, a small range in which the amount of infrared light incident on the infrared sensor is near the peak is referred to as a detection beam (the detection beam is an effective area in which infrared light from a human body is to be detected). That is, by arranging the optical system on the path of incidence of infrared light to the infrared sensor, a plurality of detection beams are set for one infrared sensor.

By the way, as this kind of human body detector X, for example, as shown in FIG. 15, there is a type which is attached to an upper portion of a wall surface or the like. In the human body detector X used in such a form, a detection area is set in front of and below the human body detector X, and the range of the detection area on the floor is centered directly below the human body detector X. Is set to be a fan shape of 160 to 180 degrees with a center line being a straight line parallel to the front direction of. In the illustrated example, the detection area is set in a fan-shaped range of 160 degrees centered directly below the human body detector X on the floor. Also, when the human body detector X is installed at a height of 1.2 m from the floor, the intersection of the detection beam Bm and the floor has a radius of 1.5 m and a radius of 3 m centered directly below the human body detector X. Are designed so as to be located on the fan-shaped arcs of the above and that the respective fan-shaped arcs are divided into approximately seven equal parts.
In the illustrated example, a pyroelectric infrared sensor in which two element elements (that is, light receiving elements) are provided in one package is used. This type of pyroelectric infrared sensor is called a dual type element. In the dual type element, the two element elements are connected such that the output changes in directions opposite to each other when the amount of infrared light incident on each element element changes.

In the above-described human body detector X, a detection beam Bm is set so that one end is located on an arc having a small radius.
Is set to enable detection even when a person who is shorter than the height at which the human body detector X is mounted moves around the human body detector X. In this way, by locating one end of the detection beam Bm on two large and small arcs, it is possible to detect the presence or absence of a person and the movement of the person regardless of the height.

By the way, in order to set the detection beam as described above, as shown in FIG. 16, an optical element arranged on an incident path of infrared rays to a pyroelectric infrared sensor (hereinafter abbreviated as a sensor) 1 is used. The system is configured by combining a lens body 2 and a mirror 3 (mirror 3 includes a support member) as an optical element for turning infrared rays (for a similar configuration, see Japanese Patent Application Laid-Open No. 10-213772).

In order to set the fourteen detection beams Bm as described above, fourteen lenses 21 are formed on the lens body 2 and the optical axis of each lens 21 is set to the detection beam Bm.
m center line. Now, the human body detector X on the floor
If a straight line in a direction parallel to the front direction of the human body detector X (that is, the above-described fan-shaped center line) is set as a reference line from immediately below,
The angle formed by a straight line connecting one end of the center line of the detection beam Bm and the center on the floor surface to the reference line is 0 degree, 26 degrees, and 52 degrees.
Degrees, 79 degrees. The lens body 2 includes a front piece 2a substantially parallel to the light receiving surface of the sensor 1, and a pair of left and right side pieces 2b extending obliquely rearward from both side edges of the front piece 2a.
And the angle between the side piece 2b and (180-52) degrees. Each lens 21 is a plano-convex lens body formed such that the surface on the sensor 1 side of the front piece 2a and the side piece 2b is convex.

Here, the six lenses 2 provided on the front piece 2a
Reference numeral 1 designates a detection beam Bm corresponding to 0 degree and 26 degrees, and four lenses 21 provided on each side piece 2b.
Sets the detection beam Bm corresponding to 52 degrees and 79 degrees. Lens 2 for setting detection beam Bm corresponding to 0 degree
1 (a1, a2) are arranged above and below the center of the front piece 2a, and the lenses 21 (b1, b2) corresponding to 26 degrees are arranged above and below the left and right sides of the lens 21 (a1, a2) in the front piece 2a. Are located. The lenses 21 (c1, c2) corresponding to 52 degrees are formed above and below the rear part of the side piece 2b, and the lenses 21 (d1, d2) corresponding to 79 degrees are formed above and below the front part of the side piece 2b. It is formed.

Since the lens 21 is arranged as described above, the infrared ray passing through the lens 21 (d1, d2) corresponding to 79 degrees cannot be incident on the light receiving surface of the sensor 1 as it is. Therefore, the lens 2 corresponding to 79 degrees
A mirror 3 is provided for diverting the infrared light passing through 1 to enter the sensor 1. A pair of mirrors 3 is provided on the left and right sides, and lenses 21 provided on the front piece 2a respectively.
It is located near the boundary of. However, the size and position of the mirror 3 are set so that infrared rays passing through the lens 21 provided on the front piece 2a can enter the sensor 1.

[0009]

By the way, the infrared rays incident on the sensor 1 are not limited to the infrared rays that have passed through the lens 21, but also the infrared rays that have passed through portions other than the lens 21 in the lens body 2. Also,
When the mirror 3 is disposed in front of the sensor 1 as described above, the infrared light reflected on a surface other than the reflection surface of the mirror 3 also enters the sensor 1. Mirror 3
The reason that infrared rays are reflected at other than the required reflection surface at
This is because the mirror 3 is made of a resin molded product and is entirely chrome-plated from the viewpoint of manufacturing the mirror 3 (processing method and strength). That is, it is not possible to avoid that a reflection surface other than the necessary reflection surface is formed in the mirror 3.

However, infrared rays that enter the sensor 1 through a path other than the desired path are unnecessary stray light, and a detection beam other than the detection beam that is set to generate the stray light may be generated. The detection beam generated by the stray light is referred to as a stray light beam (the stray light beam becomes an invalid area where the human body should not be detected). When a stray light beam is generated, infrared rays from a site different from the designed detection area are detected, resulting in malfunction.

Here, since infrared rays passing through portions other than the lens 21 are generally out of focus, for example, in a sensor 1 having four element elements 16 as shown in FIG. Element element 1
Infrared rays are superimposed on 6 and incident. Even if the infrared rays are simultaneously incident on the element elements 16 of different polarities, they cancel each other out, so that no output is obtained. An area where a malfunction due to the beam is likely to occur is about the range of the hatched portion shown in FIG. 17, and since this area is very narrow, the sensitivity to the stray light beam is low. That is, the lens 21 in the lens body 2
It is possible to prevent a malfunction due to a stray light beam even if the thickness of other parts is increased.

However, when a pair of left and right mirrors 3 is disposed in front of the sensor 1 as in the configuration shown in FIG.
In order to make infrared rays incident on the sensor 6, the sensor 1 is rotated 45 degrees as shown in FIG. When the sensor 1 is arranged in this way, stray infrared light cannot be simultaneously incident on the element elements 16 of different polarities. In particular, stray light from the front of the light receiving surface (the surface on which the element elements 16 are arranged) of the sensor 1 It cannot be offset. In other words, the sensitivity to stray light is higher near the front of the light receiving surface of the sensor 1 than in other directions (indicated by fine diagonal lines), and the sensitivity to stray light can be reduced by adjusting the thickness of the lens body 2. Disappears.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an infrared human body detector in which a malfunction due to stray light is prevented by a simple configuration.

[0014]

According to a first aspect of the present invention, there is provided an infrared sensor for detecting infrared rays radiated from a human body, and an infrared sensor disposed in front of a light receiving surface of the infrared sensor to collect infrared light on the light receiving surface of the infrared sensor. And an optical system for setting an effective area for detecting infrared rays, wherein at least a part of a portion of the optical system that is not used for setting the effective area is roughened.

According to a second aspect of the present invention, in the first aspect of the present invention, the optical system has a lens body integrally provided with a plurality of lenses arranged in a row in front of a light receiving surface of an infrared sensor.
At least some of the front and rear surfaces of the lens body where no lens is formed are roughened.

According to a third aspect of the present invention, there is provided an infrared sensor for detecting infrared radiation emitted from a human body, and an infrared sensor which is disposed in front of a light receiving surface of the infrared sensor and which collects infrared light on the light receiving surface of the infrared sensor and detects the infrared light. An optical system for setting an effective area, wherein the optical system has an optical element disposed so as to change the incident path of the infrared ray in the field of view of the light receiving surface of the infrared sensor, and the infrared ray should not be detected The optical element is provided with sensitivity reducing means for reducing the sensitivity to infrared light incident on the infrared sensor from the invalid area.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the sensitivity reducing means is a rough surface formed on the optical element.

According to a fifth aspect of the present invention, there is provided an infrared sensor for detecting infrared rays emitted from a human body, and the infrared sensor is disposed in front of the light receiving surface of the infrared sensor to collect the infrared rays on the light receiving surface of the infrared sensor and detect the infrared rays. An optical system for setting an effective area, wherein the optical system has an optical element disposed so as to change an incident path of infrared light within a field of view of a light receiving surface of the infrared sensor, and the infrared sensor is a pyroelectric element. A plurality of element elements having different output voltage polarities, and a path through which infrared light from the effective area enters the first element element after reflection by the optical element, and a first element element without passing through the optical element The second is of the same polarity as
The optical element is arranged so as to pass through two paths of the element element and the path incident on the element element.

According to a sixth aspect of the present invention, in the third or fourth aspect, the sensitivity reducing means is a curved surface formed on the optical element.

According to a seventh aspect of the present invention, in the sixth aspect of the invention, the sensitivity reducing means is a convex curved surface which scatters infrared rays from an invalid area in the optical element.

According to an eighth aspect of the present invention, in the sixth aspect of the present invention, the sensitivity reducing means is a concave curved surface for converging infrared rays from an ineffective area in the optical element between the infrared sensor and the optical element. .

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment First, a circuit configuration for detecting the presence or absence or movement of a person based on the output of a pyroelectric infrared sensor (hereinafter, sensor) will be described. The infrared radiation emitted from the human body, as shown in Figure 2,
It is detected by the sensor 1 through an optical system 4 described later.
After the output of the sensor 1 is amplified by the amplifying unit 11, the output of the sensor 1 is passed through a band-pass filter 12 to remove unnecessary frequency components serving as noise, and it is determined whether or not the output of the comparison circuit 13 is equal to or higher than the reference level. Is determined. If the output level of the sensor 1 (actually, the output of the bandpass filter 12) is equal to or higher than the reference level, a load such as an illumination load is controlled through the delay circuit 14 and the output circuit 15.

Here, the sensor 1 is of a differential type, and no output is obtained when the rate of change of the amount of infrared light incident on the sensor 1 is small. Therefore, a person is present in the field of view (detection area) of the sensor 1. Also, a period occurs in which the output level of the sensor 1 becomes lower than the reference level. Therefore, the optical system 4 that causes uneven sensitivity in the field of view of the sensor 1 so that the rate of change of infrared rays incident on the sensor 1 becomes relatively large even if the movement of a person present in the field of view of the sensor 1 is minute. Is used. Further, even if a period occurs in which the output level of the sensor 1 becomes equal to or lower than the reference level, a delay circuit 14 is provided so that load control (for example, lighting of an illumination load) is continued if the period is short. is there. That is, the time constant of the delay circuit 14 is set to such an extent that load control is continued while a person is present in the detection area. The output circuit 15 is configured according to the load, and for example, a relay or a triac inserted in a power supply path to the load is used.

If the load is a lighting load, a detection area is set in the room where the lighting load is installed, and the lighting load is turned on / off according to the presence or absence of a person in the room. It becomes possible. That is,
When a person is first detected based on the output of the sensor 1, the illumination load is turned on. Thereafter, when the presence of the person is detected again based on the output of the sensor 1 within the time set by the delay circuit 14, the illumination is turned on. The lighting state of the load is continued, and the lighting state of the illumination load is extended until no person is detected within the time set by the delay circuit 14 finally. In other words,
The lighting load continues to be turned on while a person is present in the detection area of the sensor 1, and turns off when a time set in the delay circuit 14 elapses after the person no longer exists.

By the way, if a sensor having one element element is used as the sensor 1, the bandpass filter 1
2 (a) to 3 (c) according to the moving speed of the person.
It changes like The reason why the output waveform of the bandpass filter 12 changes in accordance with the moving speed of the person depends on the relationship between the frequency component of the output of the sensor 1 and the frequency characteristics of the bandpass filter 12. When a dual type element having two element elements is used as the sensor 1 and a person sequentially passes through a region corresponding to both element elements, the bandpass filter 1 is used.
4 (a) to 4 (c) according to the moving speed of the person.
It changes like Here, when a person passes through the area corresponding to the two element elements, as the angle of the movement direction of the person with respect to the direction connecting the two areas increases, the waveform approaches the change waveform at low speed.

As described above, when a dual type element in which two element elements are housed in a package is used as the sensor 1, the detection state greatly changes depending on the direction of movement of a person. As shown in FIG. 5, a four-element type element in which four element elements 16 are housed in a package 17 is used. Hereinafter, the surface on which the element elements 16 are arranged is referred to as a light receiving surface. Each element element 16 of the sensor 1 is 0.5 mm × 0.5 mm, and is arranged so as to be located at the apex of the square, and each two element elements 16 located on each diagonal of the square are The element elements 16 on the same diagonal line and on the other diagonal lines are arranged so as to have different polarities (the polarities are indicated by + and-signs in the figure). Further, when incorporated in the human body detector X, the squares having the element elements 16 as vertices are arranged so that one diagonal line of the squares is in the vertical direction. That is, 4 from the position in FIG.
It is arranged in a state rotated by 5 degrees.

In the present embodiment, in order to facilitate comparison with the conventional configuration, the detection area is set in a fan-shaped range centered immediately below the human body detector X (see FIG. 6) on the floor and approximately 160 degrees. Set. When the human body detector X is installed at a height of 1.2 m from the floor, the intersection of the center line of the detection beam and the floor has a radius of 1.5 m centered directly below the human body detector X. The optical system 4 is designed so as to be located on a fan-shaped arc having a radius of 3 m and to divide each fan-shaped arc into approximately seven equal parts. Now, if a straight line in a direction parallel to the front direction of the human body detector X from immediately below the human body detector X on the floor surface (that is, the center line of the above-mentioned fan) is set as a reference line, the detection beam on the floor surface The angle between the straight line connecting one end of the center line and the center and the reference line is 0 degree, 26 degrees, 52 degrees.
Degrees, 79 degrees. Then, four detection beams corresponding to the respective element elements 16 are formed around the intersection between the center line of the detection beam and the floor. Further, since the detection beam is set as described above, the inclination angle of the center line of the detection beam is about 20 degrees with respect to an arc having a radius of 3 m and the radius is 1.5.
It is set to about 40 degrees for the arc of m. With such a setting, if the height is 70 cm or more, it is possible to detect presence or absence or movement in the detection area. In the following, as shown in FIG.
The detection beams of degrees, 52 degrees, and 79 degrees are referred to as beam A, beam B, beam C, and beam D, respectively. Also, regarding the detection beams of 0 degree, 26 degrees, 52 degrees, and 79 degrees on an arc having a radius of 1.5 m, beams A ′, B ′,
The beams are referred to as beam C 'and beam D'. Since the detection beams are formed symmetrically, two beams other than the beams A and A 'are formed.

In this embodiment, in order to form the 14 detection beams as described above, the mirror 3 fitted on the sensor 1 having the cylindrical package 17 as shown in FIG. An optical system 4 is constituted by the lens body 2 disposed in front of the optical system 3. The lens body 2 includes a plurality of lenses 21 as in the conventional configuration. However, instead of providing the lens 21 for each detection beam, FIG.
As shown in (b), two lenses 21 are shared by four detection beams (beams C, C ′, D, D ′). In addition, individual lenses 21 are used for the remaining six detection beams (beams A, A ', B, and B'). Therefore, eight lenses 21 are provided. In the present embodiment, five of the eight lenses 21 are arranged in the upper stage, and three are arranged in the lower stage, and four of the two lenses 21 located at both ends of the upper stage are arranged. This is a configuration that is shared by the detection beams.

Each lens 21 is, as shown in FIGS.
The dome portion 22 is arranged along the dome portion 22 that forms a part (about a quarter) of the spherical surface. The outer surface of the dome portion 22 is almost smoothly continuous, and the inner surface of the dome portion 22 corresponds to each lens 21. The part to be formed becomes an uneven surface protruding. Here, the upper and lower left and right end lenses 21 are plano-convex lens bodies each having an outer surface (first surface) formed in a planar shape, and the optical axis of the lens 21 passes between the center lines of the beams C and D. It is set as follows. That is, since the center lines of the beams C and D are 52 degrees and 79 degrees in the horizontal plane, respectively, the optical axis of the lens 21 is 6 degrees.
It is set to about 7 degrees. The inner side surface of each lens 21 forms a part of a spherical surface.

The dome portion 22 is formed of high-density polyethylene so as to transmit infrared rays radiated from the human body, and is continuous with the frame 20 attached to the sensor 1 and the body housing the above-mentioned circuit portion. It is formed integrally. The frame 20 is a hollow frame body 23
A pair of mounting pieces 24 extend on both left and right sides of the rear end portion, and a dome portion 22 projects from an upper portion of the front surface of the frame main body 23. Guide pieces 25a, 25b is extended. The mounting piece 24 is coupled to the body, and houses the sensor 1 and the circuit unit together with the body. The peripheral edges of the guide pieces 25a and 25b are continuous with the side edges of the frame body 23 in a semicircular shape.
The dome portion 22 is formed so as to fit within the projection planes a and 25b. The upper end of the dome portion 22 is the upper guide piece 2
5a, and the lower end of the dome portion 22 is the lower guide piece 2.
5b. A gap 26 is formed between the frame main body 23 and each mounting piece 24 so that an end of a light shielding member described later can be inserted into the gap 26 and slidable along the peripheral edges of the guide pieces 25a and 25b. , The detection area can be adjusted by the light shielding member. Further, a plurality of locking grooves 27 for locking and positioning the light shielding member are formed on the peripheral edges of the guide pieces 25a and 25b.

Here, in the horizontal plane, the guide piece 25b
Since the radius of curvature of the dome portion 22 is smaller than that of the dome portion 22 and the diameter of the dome portion 22 in the horizontal plane becomes smaller toward the lower portion, the distance in the horizontal plane from the peripheral surface of the dome portion 22 to the peripheral edge of the guide piece 25b is: It is the smallest in the front direction of the dome portion 22 and becomes larger as the side portion. That is, each lens 21
The possibility that the guide beam 25b will cause the detection beam formed corresponding to the above to be larger at the lower part and the side of the dome portion 22. Therefore, by disposing the lower lens 21 of the upper and lower lenses 21 near the front surface and not providing the lenses 21 at both left and right ends, it is possible to prevent the detection beam from being shaken by the guide piece 25b. That is,
Substantially the entire surface of the lens 21 is used for an infrared ray incident path, and high detection sensitivity can be obtained.

In this embodiment, both the front and back surfaces of the hatched portion in FIG. 1A, which is the upper periphery of the upper lens 21 forming the beams A, B, C and D in the lens body 2, are roughened. P (manufacturing is easy if a rough surface P is formed in a region of a constant width along the upper edge of the lens body 2). In other words, the infrared light incident on the lens body 2 is scattered by the rough surface P on the front surface side and further scattered by the rough surface P on the rear surface side, so that the infrared light is attenuated synergistically. Here, if polyethylene is used for the lens body 2, the transmittance of infrared rays is the surface roughness (expressed by the maximum unevenness).
Changes as shown in FIG. For example, when the maximum unevenness is 20 μm, the amount of infrared light transmitted through the lens body 2 is about 50% of the almost smooth surface (in the figure, the transmission amount of the almost smooth surface is about 51%, It is about 25% when the maximum unevenness is 20 μm). Therefore, about 50% attenuation occurs on the rough surface P on the front surface side and about 50% attenuation occurs on the rough surface P on the back surface side, so that about 25% attenuation occurs on both rough surfaces P. With such a configuration, unnecessary stray light can be suppressed from entering the sensor 1,
Malfunction due to stray light can be reduced.

On the other hand, the mirror 3 has an opening window 32 for exposing the element element 16 of the sensor 1 at a lower portion of a front wall of a cylindrical mirror body 31 having an open rear end surface. The mirror 3 also includes a pair of left and right first reflectors 33 extending in the vertical direction from the upper end of the opening window 32 near the left and right centers of the opening window 32 to an intermediate portion in the vertical direction, and an upper edge of the opening window 32. And a pair of left and right second reflectors 34 that protrude forward along the line. This mirror is fixed to the circuit board together with the sensor 1.

The beams A and A 'corresponding to the lens 21 positioned at the center of both the upper and lower stages are provided between the left and right first reflecting portions 33.
A gap 35 (see FIG. 10) that allows the light to directly enter the light receiving surface of the sensor 1 is formed, and the first reflection portions 33 are arranged so that the distance between them increases toward the front end. In addition, the two first reflecting portions 33 detect the lenses 21 located on the left and right sides on the lower stage and the beams B and B ′ corresponding to the upper lens 21 without passing through the gap 35 between the first reflecting portions 33. It is arranged so that it can be directly incident on one light receiving surface. Further, the outer surface of the first reflecting portion 33 functions to reflect the beam D passing through the lenses 21 located at the left and right ends on the upper stage and make the beam D incident on the light receiving surface of the sensor 1. The lenses 21 located at the left and right ends of the upper stage also pass the beam C as described above, but the beam C is directly incident on the light receiving surface of the sensor 1.

The second reflector 34 is formed so as to reflect the beam C ′ passing through the lenses 21 at the left and right ends of the upper stage and to guide the beam C ′ to the light receiving surface of the sensor 1. The second reflector 34 also has a function of reflecting the beam D ′ passing through the same lens 21, reflecting the beam D ′ by the first reflector 33, and then introducing the beam D ′ to the light receiving surface of the sensor 1.

As described above, the beams C ′, D, and D ′ are reflected by at least one of the first reflector 33 and the second reflector 34 and guided to the light receiving surface of the sensor 1. Further, the above-described configuration allows the area of the reflecting surfaces of the first reflecting portion 33 and the second reflecting portion 34 to be relatively large, and the first reflecting portion 33 and the second
It is possible to avoid shaking due to the reflecting portion 34,
It is possible to prevent a decrease in sensitivity due to eclipse. In addition, the beams A 'and B' are placed in the first reflection portion 3 in the optical path.
No loss is caused by reflection because no 3 intervenes, so that the sensitivity of the beams A 'and B' does not decrease.

Here, the focal length of the lens 21 is 6
mm, the back focus in the optical path passing through the lens 21 and the mirror 3 is about 7 mm, and the focal points do not match, but the lower lens 21 does not overlap with the upper lens 21 and the entire surface of the lens 21 is effective. Therefore, high sensitivity can be obtained. Also, mirror 3
Is used, the angle of incidence of infrared rays on the light receiving surface of the sensor 1 (the angle between the incident light beam and the normal to the light receiving surface) is reduced, so that the defocus of the detection beam is also reduced,
This also improves the detection sensitivity.

In this embodiment, the sensor 1 has four sensors.
Although an element type element is used, a dual type element can also be used. When a dual type element is used, both element elements may be arranged in a direction along the wall surface or in a direction perpendicular to the wall surface. Although only a part of the lens 21 is a plano-convex lens, all the lenses 21 are plano-convex lenses.
2 may be formed in a polygonal shape. Beams C, C ', D,
The lens 21 through which D 'passes may have its optical axis coincident with the center line of any of the four detection beams.

Here, if the rough surface P is formed on the front surface side of the lens body 2, the appearance may be deteriorated. However, the appearance problem can be solved by providing a decorative cover for covering the lens body 2. As a decorative cover, a milky white flexible sheet-like strip is used, and guide pieces 25a, 25b are used.
The decorative cover may be arranged along the leading edge of the cover. In this case, the dome portion 22 is covered by the guide pieces 25a and 25b and the decorative cover. In the case where a decorative cover is provided, if the portion of the back surface of the decorative cover through which the detection beam does not pass is set as the rough surface P, the sensitivity to the invalid area can be further reduced. In addition, the lens body 2 is not necessary for forming a detection beam, such as a part other than the above-described part except the lens 21 or a part of the lens 21 which is not effectively used due to being shaken by another member. If a rough surface P is formed for a portion having the above, stray light can be more reliably prevented from being generated. Further, since the rough surface P can be formed when the lens body 2 is formed, the rough surface P is separately formed after the lens body 2 is formed.
It is possible to produce at low cost without the need for a step of forming the substrate.

(Second Embodiment) In the first embodiment, the rough surface P is formed in a portion of the lens body 2 which does not contribute to the formation of the detection beam.
Of these, the rough surface P is formed at a portion that does not contribute to the formation of the detection beam. As described in the first embodiment, the gap 35 is formed between the left and right first reflectors 33, and the beams A and A 'are applied to the first reflector 33 as shown by solid lines in FIG. Infrared light passes through the space. However, in the first reflecting portion 33, the gap 35
When the infrared ray is reflected on any of the surfaces sandwiching, the infrared ray enters the element element 16 along a path shown by a broken line in FIG. 10, whereby a stray light beam is formed. That is, an invalid area that does not need to detect a human body is formed.

Therefore, in this embodiment, the surface of the first reflecting portion 33 sandwiching the gap 35 is defined as a rough surface P, so that the amount of infrared light incident on the element element 16 along a path shown by a broken line in FIG. It is attenuated to suppress the resulting stray light beam. That is, malfunction due to the stray light beam can be reduced. Other configurations and operations are the same as those of the first embodiment. In this embodiment, since the rough surface P can be formed when the mirror 3 is formed, the step of forming the rough surface P after the mirror 3 is formed And can be produced at low cost. Here, in order to suppress the generation of stray light in the mirror 3, it is conceivable to suppress reflection by two-color plating instead of forming the rough surface P, but the two-color plating is applied to the mirror 3.
This is a separate step from the molding of the mirror 3, which leads to an increase in cost. On the other hand, if the technology of the present embodiment is applied, the rough surface P can be formed at the same time when the mirror 3 is molded, and the cost can be reduced. be able to.

It should be noted that, in place of the rough surface P, the uneven surface 3 shown in FIG.
6 may be formed (the figure is an enlarged view, and the actual unevenness is minute). The concave-convex surface 36 has a sawtooth-shaped cross section, and is formed so as to attenuate the infrared light incident on the concave portion by being reflected many times. Generally, the mirror 3 formed by applying chromium plating to a synthetic resin attenuates infrared rays by about 10% by one reflection. Therefore, if the reflection is repeated at least five times in the concave portion, the amount of incident infrared rays can be reduced. On the other hand, the amount of infrared rays can be attenuated to about 50%.

(Third Embodiment) In this embodiment, the first embodiment
By appropriately setting the position and angle of the surface sandwiching the gap 35 in the reflecting section 33, the infrared rays reflected on this surface and incident on the element element 16 are emitted from the beams A and
It is made to substantially overlap with A '. For example, assuming that the beam A directly enters the element element 16 on the right side of the figure without being reflected by the mirror 3 as shown by the solid line in FIG. 12, the beam A is reflected by the mirror 3 and is reflected by the element element 16 on the left side of the figure. The position and the angle of the mirror 3 are set so that the infrared light incident on the mirror 3 substantially overlaps the beam A before being reflected by the mirror 3 as shown by the broken line in FIG. Here, as described in the first embodiment,
The sensor 1 is arranged to be rotated 45 degrees, and the left and right element elements 16 in FIG. 12 have the same polarity.
Even if infrared rays enter the sensor 1 along a path as indicated by the broken line in FIG. 12, it is equivalent to the beam A and no stray light beam is generated.

As shown by a broken line in FIG.
The path through which the infrared rays are reflected by the element element 16 on the left side of the figure is incident on the element element 16 on the right side of the figure without being reflected by the mirror 3 as shown by the solid line in FIG. Since the back focus is long and the beam indicated by the broken line is narrower than the beam A indicated by the solid line, there is no problem even if the beam indicated by the broken line is slightly shifted from the beam A indicated by the solid line.

As described above, the gap 35 in the mirror 3
Since the stray light beam is substantially prevented from being generated by appropriately setting the angle and the position of the surfaces facing each other with the interposed therebetween, malfunction due to the stray light beam is reduced, and furthermore, the shape overlapping the original beam is reduced. By forming a beam of a different path, it is possible to expect an improvement in sensitivity. Other configurations and operations are the same as those of the first embodiment. If the surfaces on both sides of the gap 35 are made rough as in the second embodiment, the sensitivity to the invalid area can be further reduced.

(Fourth Embodiment) The third embodiment focuses on the design conditions of the mirror 3, but cannot be applied unless the sensor 1 has four element elements 16. In the present embodiment, a technique applicable to the sensor 1 including the two element elements 16 will be described. That is, as shown in FIG.
The portion sandwiching 5 is a convex curved surface 37 that is convex toward the lens body 2 side.

According to this configuration, as shown by the broken line in FIG. 13, the infrared light reflected by the convex curved surface 37 of the mirror 3 is diffused, and the amount of the infrared light incident on the element 16 of the sensor 1 is very small. That is, there is little possibility that a stray light beam is formed, and even if a stray light beam is formed, the sensitivity becomes extremely small. As a result, malfunctions due to the influence of the stray light beam can be reduced. Other configurations and operations are the same as those of the first embodiment. In addition, convex curved surface 3
If the surface 7 is made rough as in the second embodiment, the sensitivity to the invalid area can be further reduced.

(Fifth Embodiment) The present embodiment relates to a fourth embodiment.
This is a technique applicable to the sensor 1 including the two element elements 16 in the same manner as in the embodiment described above, in which a portion sandwiching the gap 35 in the mirror 3 is a concave curved surface 38 which is recessed from each other.

According to this configuration, as shown by a broken line in FIG. 14, the infrared light reflected by the concave curved surface 38 of the mirror 3 converges before entering the sensor 1 (the converging portion is indicated by f). Infrared rays incident on the path indicated by the broken line in FIG. 14 have a longer back focus due to reflection on the mirror 3, so that when they are incident on the sensor 1, they are out of focus and blurred, but are converged by the concave curved surface 38. When the position is closer to the sensor 1, the blur becomes larger.
That is, the amount of infrared rays incident on the sensor 1 is reduced, and the sensitivity is reduced even if a stray light beam is formed as a result.
That is, malfunctions due to the influence of the stray light beam can be reduced. Other configurations and operations are the same as those of the first embodiment. Further, if the concave curved surface 38 is made rough as in the second embodiment, the sensitivity to the invalid area can be further reduced.

It is needless to say that the above-described embodiments may be combined as appropriate if they can be combined. For example, the one that forms a rough surface on the lens body 2 as in the first embodiment is combined with the one that forms a rough surface on the mirror 3 as in the second to fifth embodiments. It can be used.

[0051]

According to the first aspect of the present invention, there is provided an infrared sensor for detecting infrared radiation radiated from a human body, and an infrared sensor disposed in front of a light receiving surface of the infrared sensor for collecting infrared light and detecting the infrared light on the light receiving surface of the infrared sensor. An optical system for setting an effective area to be provided, and at least a part of a portion not used for setting the effective area in the optical system is a rough surface,
Since infrared rays are scattered at the part where the rough surface is formed, the amount of infrared rays incident on the infrared sensor through the part that does not contribute to the setting of the effective area is reduced, and as a result, there is a possibility that a human body outside the effective area will be detected and malfunction will occur. There is an advantage that it can be reduced.

According to a second aspect of the present invention, in the first aspect, the optical system has a lens body integrally including a plurality of lenses arranged in a row in front of a light receiving surface of the infrared sensor. Since the front and back surfaces of at least a part of the portion where no is formed are roughened, the manufacturing is easy because only the roughened surface is formed when the lens is processed.

According to a third aspect of the present invention, there is provided an infrared sensor for detecting infrared radiation emitted from a human body, and an infrared sensor which is disposed in front of a light receiving surface of the infrared sensor and which collects infrared light on the light receiving surface of the infrared sensor and detects the infrared light. An optical system for setting an effective area, wherein the optical system has an optical element arranged so as to change the incident path of the infrared ray in the field of view of the light receiving surface of the infrared sensor, and the infrared ray should not be detected The optical element is provided with sensitivity reduction means for reducing the sensitivity to infrared light incident on the infrared sensor from the region, and the amount of infrared light incident on the infrared sensor that is deflected at a portion of the optical element that does not contribute to the setting of the effective area is reduced. Therefore, there is an advantage that the possibility of detecting a human body outside the effective area and malfunctioning can be reduced as a result.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the sensitivity reducing means is a rough surface formed on the optical element. Since the light is scattered, the amount of infrared light that enters the infrared sensor from the invalid area is reduced, and the possibility of malfunction is reduced.

According to a fifth aspect of the present invention, there is provided an infrared sensor for detecting infrared radiation emitted from a human body, and an infrared sensor which is disposed in front of a light receiving surface of the infrared sensor and which collects infrared light on the light receiving surface of the infrared sensor and detects the infrared light. An optical system for setting an effective area, the optical system having an optical element arranged so as to change an incident path of infrared light within a field of view of a light receiving surface of the infrared sensor, and the infrared sensor is made of a pyroelectric element. A plurality of element elements having different output voltage polarities are provided, and have the same polarity as the first element element without passing through the optical element and a path through which infrared light from the effective area enters the first element element after reflection by the optical element. The optical element is arranged so as to pass through two paths, that is, a path incident on the second element element, and the first element element and the second element element having the same polarity have an effective area. Infrared can be made to be incident at the same time, the possibility of infrared incident from the results ineffective region to infrared sensor is reduced. Further, since the infrared rays from the effective area are simultaneously incident on the first and second element elements having the same polarity, the sensitivity is increased accordingly.

According to a sixth aspect of the present invention, in the third or fourth aspect, the sensitivity reduction means is a curved surface formed on the optical element, and infrared rays from the ineffective area pass through the optical element to the infrared sensor. The possibility of incidence is reduced.

According to a seventh aspect of the present invention, in the sixth aspect of the invention, the sensitivity reducing means is a convex curved surface which scatters infrared rays from an invalid area in the optical element, and the infrared rays from the invalid area are scattered by the optical element. Therefore, the amount of infrared light that enters the infrared sensor from the invalid area is reduced.

According to an eighth aspect of the present invention, in the sixth aspect of the invention, the sensitivity reducing means is a concave curved surface for converging infrared rays from an ineffective area in the optical element between the infrared sensor and the optical element. Since the infrared light from the area is converged between the infrared sensor and the optical element by the optical element, the amount of infrared light that enters the infrared sensor from the invalid area is reduced.

[Brief description of the drawings]

1A and 1B show a first embodiment of the present invention, wherein FIG. 1A is an exploded perspective view of a main part, and FIG. 1B is a schematic configuration diagram of a main part.

FIG. 2 is a block diagram of a circuit used in the embodiment.

FIG. 3 is an operation explanatory diagram of the above.

FIG. 4 is an operation explanatory view of the above.

FIG. 5 is a front view of the infrared sensor used in Embodiment 1;

FIG. 6 is an operation explanatory diagram showing an example of setting a detection area according to the first embodiment;

FIGS. 7A and 7B show a lens body used in the above, wherein FIG. 7A is a sectional view, FIG. 7B is a rear view, and FIG.

FIG. 8 is a horizontal sectional view of the lens body used in the above.

FIG. 9 is an explanatory diagram showing a relationship between surface roughness of the lens body and transmittance in the above.

FIG. 10 is a cross-sectional view of a principal part showing a second embodiment of the present invention.

FIG. 11 is a sectional view of a main part showing another configuration example of the above.

FIG. 12 is a cross-sectional view of a main part showing a third embodiment of the present invention.

FIG. 13 is a sectional view of a main part showing a fourth embodiment of the present invention.

FIG. 14 is a cross-sectional view of a main part showing a fifth embodiment of the present invention.

FIG. 15 is an operation explanatory diagram showing an example of setting a detection area in a conventional example.

16A and 16B show a conventional example, in which FIG.
FIG.

FIG. 17 is an operation explanatory diagram showing a problem of the conventional example.

FIG. 18 is an operation explanatory diagram showing a problem of the conventional example.

[Explanation of symbols]

 Reference Signs List 1 sensor 2 lens body 3 mirror 4 optical system 16 element element 21 lens 37 convex curved surface 38 concave curved surface P rough surface

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinji Kiribata 1048 Kazuma Kadoma, Osaka Prefecture F-term in Matsushita Electric Works Co., Ltd. DD87 GG21 GG54 GG66

Claims (8)

[Claims] An infrared sensor for detecting infrared rays emitted from a human body, an infrared ray sensor disposed in front of a light receiving surface of the infrared sensor, condensing the infrared light on the light receiving surface of the infrared sensor, and setting an effective area for detecting the infrared light. An infrared human body detector comprising: an optical system, wherein at least a part of a portion of the optical system that is not used for setting an effective area is roughened. 2. The optical system has a lens body integrally including a plurality of lenses arranged in a row in front of a light receiving surface of an infrared sensor, and at least a part of a portion of the lens body where no lens is formed. The infrared human body detector according to claim 1, wherein both front and back surfaces are roughened. 3. An infrared sensor for detecting infrared radiation radiated from a human body, and an infrared light sensor disposed in front of a light receiving surface of the infrared sensor for condensing infrared light on the light receiving surface of the infrared sensor and setting an effective area for detecting infrared light. An optical system, wherein the optical system has an optical element disposed so as to change the incident path of the infrared ray in the field of view of the light receiving surface of the infrared sensor, and the infrared sensor from the ineffective area where infrared rays should not be detected. An infrared human body detector, wherein a sensitivity reducing means for reducing sensitivity to infrared light incident on the optical element is provided in the optical element. 4. The infrared human body detector according to claim 3, wherein said sensitivity reducing means is a rough surface formed on said optical element. 5. An infrared sensor for detecting infrared radiation radiated from a human body, and an infrared ray sensor disposed in front of a light receiving surface of the infrared sensor for condensing infrared light on the light receiving surface of the infrared sensor and setting an effective area for detecting infrared light. An optical system, wherein the optical system has an optical element disposed so as to change an incident path of infrared light within a field of view of a light receiving surface of the infrared sensor, and the infrared sensor is formed of a pyroelectric element and has an output voltage polarity. Include a plurality of element elements different from each other, and a first path through which the infrared light from the effective area enters the first element element after being reflected by the optical element and does not pass through the optical element.
An infrared human body detector, wherein the optical element is disposed so as to pass through two paths, that is, a path incident on a second element element having the same polarity as the element element. 6. An infrared human body detector according to claim 3, wherein said sensitivity reducing means is a curved surface formed on said optical element. 7. An infrared human body detector according to claim 6, wherein said sensitivity reducing means is a convex curved surface which scatters infrared light from an invalid area in said optical element. 8. The optical system according to claim 6, wherein said sensitivity reducing means is a concave surface for converging infrared rays from an ineffective area in said optical element between an infrared sensor and said optical element.
An infrared human body detector as described.