TWI681173B - Infrared detection apparatus - Google Patents

Abstract

An object of the present invention is to provide an infrared detection device that can suppress unevenness in sensitivity in a detection area. The plurality of first lenses (50a) of the first light-receiving unit (2a) respectively correspond to one of the small detection areas (13) in the plurality of small detection areas (13); The plurality of second lenses (50b) of the unit (2b) respectively correspond to one of the plurality of small detection areas (13). The optical axis of the second light receiving element (30b) of each of the plurality of second light receiving units (2b) is different from the optical axis of the first light receiving element (30a) of the first light receiving unit (2a) The direction is inclined. Among the plurality of small detection areas (13), the number of the first group of small detection areas (13) corresponding to the first light receiving unit (2a) is higher than that of the plurality of small detection areas (13). The second light receiving units (2b) respectively correspond to a larger number of small detection areas (13) of the second group.

Description

Infrared detection device

The present invention generally relates to an infrared detection device, and more specifically, to an infrared detection device provided with a light receiving system that receives infrared light from a detection area.

In the past, as an infrared detection device, for example, a hot-wire type human body sensor is known, which detects whether a person exists in a specific detection area by detecting the hot rays (infrared rays) emitted from the human body (Japanese Patent Application Publication No. 2000-131136 : Hereinafter referred to as Document 1).

The hot wire type human body sensor described in Document 1 includes a sensor element and a light-receiving lens (hereinafter referred to as "multi-lens"). The sensor element detects the heat rays radiated from the human body and generates an output that reflects the temporal change of the amount of incident heat rays. The multi-lens is composed of a collection of a plurality of tiny lenses (hereinafter referred to as "lenses") that converge the hot line of each area in the detection area to the sensor element.

The multi-lens is formed in a hemispherical shape, surrounding the light receiving surface of the sensor element. The multiple lenses of the multi-lens are arranged in a triple circle, four lenses are formed on the innermost circle, eight lenses are formed on the next largest circle, and twelve lenses are formed on the outermost circle.

In the above hot-wire type human body sensor, the amount of heat rays incident on the sensor element through the lens disposed on the outermost circle is more incident on the sensor element than through the lens disposed on the inner circle The hotline is less. Therefore, the above-mentioned hot-wire type human body sensor may have reduced sensitivity in a region corresponding to the lens arranged on the outermost circle.

An object of the present invention is to provide an infrared detection device that can suppress unevenness in sensitivity in a detection area.

An infrared detection device according to an aspect of the present invention includes a light receiving system that receives infrared rays from a detection area. This light receiving system includes a first light receiving unit and a plurality of second light receiving units. The first light receiving unit includes a first light receiving element and a first multi-lens. The first multi-lens has a plurality of first lenses that focus infrared rays to the first light-receiving element. The plurality of second light-receiving units respectively include a second light-receiving element and a second multi-lens. The second multi-lens has a plurality of second lenses that focus infrared rays to the second light-receiving element. In the infrared detection device, the plurality of small detection areas dividing the detection area correspond to any one of the first light receiving unit and the plurality of second light receiving units, respectively. In the infrared detection device, the plurality of first lenses of the first light receiving unit respectively correspond to one of the plurality of small detection areas. In the infrared detection device, each of the plurality of second lenses of the plurality of second light receiving units corresponds to one of the plurality of small detection regions, respectively. The optical axis of the second light-receiving element of each of the plurality of second light-receiving elements is inclined in different directions with respect to the optical axis of the first light-receiving element. Among the plurality of small detection areas, the number of the first group of small detection areas corresponding to the first light receiving unit is higher than that of the plurality of small detection areas corresponding to the plurality of second light receiving units, respectively. The second group of small detection areas has a larger number.

The embodiments described below are only one of various embodiments of the present invention. The following embodiments should just be able to achieve the purpose of the invention, and various changes can be made in accordance with the design and the like.

In addition, each drawing described in the following embodiments is a schematic diagram, and the ratio of the size and thickness of each component in the drawing is not limited to necessarily reflect the actual size ratio.

(Embodiment) Hereinafter, the infrared detection device 100 of this embodiment will be described based on FIGS. 1 to 9.

The infrared detection device 100 of this embodiment is used as an example for human body detection, and detects whether a person (detection target) exists in the detection area 11 (refer to FIGS. 4 and 6B). That is, the infrared detection device 100 is an infrared type human body detection device that performs human body detection in the detection area 11.

The infrared detection device 100 is provided with a light receiving system 1 that receives infrared rays from the detection area 11. The light receiving system 1 includes a first light receiving unit 2a and a plurality (four) of second light receiving units 2b. The first light receiving unit 2a includes a first infrared sensor 3a having a first light receiving element 30a (refer to FIGS. 4 and 6A), and a first optical member 6a having a first multi-lens 5a. The first multi-lens 5a has a plurality of (30) first lenses 50a (see FIGS. 6A and 8) for condensing infrared rays to the first light receiving element 30a. The plurality of second light-receiving units 2b respectively include: a second infrared sensor 3b having a second light-receiving element 30b (refer to FIGS. 4 and 6A), and a second optical member 6b having a second multi-lens 5b. The second multi-lens 5b has a plurality of (15) second lenses 50b (see FIGS. 6A and 8) for condensing infrared rays to the second light receiving element 30b.

In addition, the infrared detection device 100 further includes a circuit board 7. In the infrared detection device 100, a first infrared sensor 3a and a plurality of second infrared sensors 3b are mounted on the circuit board 7. Here, the first infrared sensor 3a is mounted on the circuit board 7 so that the optical axis 39a (refer to FIG. 4) of the first light receiving element 30a is slightly parallel to the thickness direction of the circuit board 7. In addition, a plurality of (four) second infrared sensors 3b are mounted on the circuit board 7 such that the optical axis 39b (refer to FIG. 4) of the second light receiving element 30b is inclined to the thickness direction of the circuit board 7 respectively. The plurality of second infrared sensors 3b are inclined in different directions from each other.

In addition, the infrared detection device 100 further includes a base 8. The base 8 holds the first light-receiving unit 2a, a plurality of second light-receiving units 2b, and the circuit board 7. Accordingly, in the infrared detection device 100, the relative positions of the first light receiving element 30a of the first infrared sensor 3a mounted on the circuit board 7 and the first multi-lens 5a are determined. In addition, in the infrared detection device 100, it is determined that the second light receiving element 30b of each of the plurality of second infrared sensors 3b mounted on the circuit board 7 corresponds to the second of the plurality of second multi-lenses 5b in one-to-one correspondence The relative position of the multi-lens 5b.

In addition, the infrared detection device 100 further includes a signal processing unit 9. The signal processing unit 9 determines whether or not someone is present in the detection area 11 based on the output signals of the first light receiving element 30a and the plurality of second light receiving elements 30b. The signal processing unit 9 is configured to output the determination result of whether or not someone is present in the detection area 11 to an external device (external circuit).

Hereinafter, each component of the infrared detection device 100 will be described in more detail.

As described above, the infrared detection device 100 includes a first infrared sensor 3a, a plurality of second infrared sensors 3b, a first multi-lens 5a, a plurality of second multi-lenses 5b, a circuit board 7, a base 8, and a signal Processing Department 9. The first light-receiving element 30a and the second light-receiving element 30b have the same structure. Therefore, in the following description, for convenience of explanation, in the case where the two are not distinguished, the light-receiving element 30 is simply referred to. In addition, for convenience of explanation, when the optical axis 39a of the first light-receiving element 30a and the optical axis 39b of the second light-receiving element 30b are not distinguished, the optical axis 39 alone is referred to. In addition, the first infrared sensor 3a and the second infrared sensor 3b have the same structure, so for convenience of explanation, in the case where the two are not distinguished, the infrared sensor 3 alone is called.

The infrared sensor 3 has a light receiving element 30. The light receiving element 30 is a thermal infrared detection element. More specifically, the light-receiving element 30 is a group of four thermoelectric elements, and four detection parts are arranged in a 2×2 array (matrix) on one thermoelectric substrate. The four detection sections are capacitors containing the following elements: the first electrode is arranged on the first surface of the pyroelectric substrate; the second electrode is arranged on the second surface opposite to the first surface; and the thermoelectric The portion between the first electrode and the second electrode in the bulk substrate. The first electrode is composed of a conductive film (for example, NiCr film) that absorbs infrared rays. The light-receiving element 30 is viewed from one direction in the thickness direction, and the optical axis 39 of the light-receiving element 30 is a normal line passing through the center of a polygon (for example, square) including the light-receiving surfaces of the four detection sections.

The light-receiving element 30 receives infrared rays and outputs a current signal in response to changes in the amount of infrared rays received. Here, the infrared sensor 3 includes an IC (Integrated Circuit) element, and the IC element includes a conversion circuit that converts the current signal output from the light receiving element 30 into a voltage signal. The conversion circuit includes, for example, a current-voltage conversion circuit and a voltage amplification circuit. The current-voltage conversion circuit is a circuit that converts the current signal of the output signal output from the light receiving element 30 into a voltage signal and outputs it. The voltage amplifier circuit is a circuit that amplifies and outputs a voltage signal of a specific frequency band (for example, 0.1 Hz to 10 Hz) in the voltage signal converted by the current-voltage conversion circuit. The voltage amplifier circuit has a function as a band-pass filter. The function of the band-pass filter is to pass the components of the above-mentioned specific frequency band in the voltage signal output from the current-voltage conversion circuit, and to remove unnecessary frequency components that become noise.

The infrared sensor 3 includes a mounting board on which the light receiving element 30 and the IC element are mounted. The mounting substrate is, for example, a molded substrate.

In addition, the infrared sensor 3 includes a package 33 (refer to FIG. 5) that houses a circuit module, and the circuit module includes a light receiving element 30, an IC element, and a mounting substrate. The package 33 is a so-called can package. Can packaging, also known as metal package (Metal Package). As shown in FIG. 5, the package 33 includes a base 331, a cover 332, a window material 333, and three lead terminals 334.

The base 331 has conductivity. Here, the base 331 is made of metal. The pedestal 331 has a disc shape, and supports the mounting substrate on one side in the thickness direction.

The cover 332 has conductivity. Here, the cover 332 is made of metal. The cover 332 is cylindrical with a bottom, and is fixed to the base 331 so as to cover the circuit module.

The window material 333 is an infrared transmission member that transmits infrared rays. The window material 333 should be electrically conductive. Here, the window material 333 includes, for example, a silicon substrate. In addition to the silicon substrate, the window material 333 is preferably provided with an infrared optical filter laminated on the silicon substrate. The infrared optical filter is an optical multilayer film that transmits infrared rays in the wavelength range of the detection target of the infrared detection device 100.

The window material 333 is configured to close the window hole 3322 formed in the front wall 3321 of the cover 332. The window material 333 is joined to the cover 332 by a conductive material, and is electrically connected to the cover 332. The window material 333 is arranged in front of the light receiving surface of the light receiving element 30. In the infrared sensor 3, the light receiving element 30 is preferably arranged such that the optical axis 39 of the light receiving element 30 passes through the center of the window material 333.

Three lead terminals 334 are held on the base 331. The three lead terminals 334 are pin-shaped, respectively. The three lead terminals 334 penetrate the base 331 in the thickness direction of the base 331. The three lead terminals 334 are a lead terminal for power supply, a lead terminal for signal output, and a lead terminal for grounding.

In the infrared detection device 100, five infrared sensors 3 are mounted on a circuit board 7 in a rectangular plate shape. The circuit board 7 is, for example, a printed board. The circuit board 7 has a first surface 71 crossing the thickness direction, and a second surface 72 opposite to the first surface 71. The infrared detection device 100 arranges four second light-receiving elements 30b on the first surface 71 side of the circuit board 7 to be arranged on a virtual circle at substantially equal intervals, and arranges the first light-receiving elements 30a At the center of the above imaginary circle. If the observation method is changed, the infrared detection device 100 places four second light-receiving elements 30b on the first surface 71 side of the circuit board 7 one by one at four corners of a virtual square, and places the first light-receiving elements 30a , Placed in the center of the virtual square.

The optical axis 39 a (refer to FIG. 4) of the first light receiving element 30 a is perpendicular to the first surface 71 of the circuit board 7. The respective optical axes 39b (refer to FIG. 4) of the plurality of second light receiving elements 30b obliquely intersect the first surface 71 of the circuit board 7. In the plurality of second infrared sensors 3b, the angles formed by the optical axis 39b of the second light receiving element 30b and the normal line passing through the center of the virtual circle are the same as each other. In addition, the plurality of second infrared sensors 3b are mounted on the circuit board 7 such that the optical axes 39b of the second light receiving elements 30b are inclined in different directions from the normal line passing through the center of the virtual circle.

On the circuit board 7, each of the three lead terminals 334 of the plurality of (5) infrared sensors 3 is passed through the three pin through holes 74 (refer to FIGS. 1 and 4), and a complex array (5 groups) is provided .

The circuit board 7 is arranged on the top surface of the central portion 801 that bulges upward in the disc-shaped base portion 8, and is held by the base portion 8. Here, a plurality of infrared sensors 3 mounted on the circuit board 7 are arranged on the bottom surface side of the central portion 801 of the base 8. The base 8 has electrical insulation. The material of the base 8 is, for example, synthetic resin.

The base portion 8 includes: a first spacer portion 81a interposed between the first infrared sensor 3a and the circuit board 7; and a plurality of second spacer portions 81b interposed between the plurality of second infrared sensors Between each pedestal 331 of 3b and the circuit board 7. A plurality of holes 82a through which the three lead terminals 334 of the first infrared sensor 3a pass one by one are formed in the first spacer portion 81a. In addition, a plurality of holes 82b through which the three lead terminals 334 of the second infrared sensor 3b pass one by one are formed in the plurality of second spacer portions 81b, respectively. The first spacer 81 a has a surface 811 a facing the base 331 of the infrared sensor 3 perpendicular to the optical axis 39 a of the first light receiving element 30 a and parallel to the first surface 71 of the circuit board 7. The plurality of second spacer portions 81b have the surface 811b facing the base 331 of the infrared sensor 3 perpendicular to the optical axis 39b of the second light receiving element 30b and inclined to the first surface 71 of the circuit board 7 .

In addition, the infrared detection device 100 preferably further includes a plurality of (four) light-shielding walls 83 (refer to FIG. 4 ). The plurality of light-shielding walls 83 are semi-cylindrical. The plurality of light-shielding walls 83 are arranged on the first semi-circle of the base 331 and the cover 332 of the second infrared sensor 3b corresponding to one-to-one correspondence among the plurality of second infrared sensors 3b, respectively. 2 Between the infrared sensor 3b and the first infrared sensor 3a. The plurality of light shielding walls 83 may be formed integrally with the base 8 or may be separately formed and fixed to the base 8.

The base portion 8 has four first walls 84 on the bottom surface side of the central portion 801 where the first optical member 6a is arranged. The four first walls 84 are viewed from the bottom surface side of the base portion 8, and each has an arc shape. 1 The optical members 6a are arranged at substantially equal intervals in the circumferential direction. In the infrared detection device 100, the first optical member 6a is fixed to two of the first walls 84 of the four first walls 84 of the base 8 by two first screws (not shown).

In addition, the base portion 8 is provided with four second walls 85 on the bottom surface side of the peripheral portion 802, each of which is provided with a plurality of second optical members 6b. The four second walls 85 are respectively viewed from the bottom surface side of the base portion 8 1 A C-shaped opening on the side of the optical member 6a. In the infrared detection device 100, a plurality of second optical members 6b are fixed to the second wall 85 of the base 8 by two second screws (not shown), respectively.

As shown in FIG. 1, the first optical member 6a includes: a first optical member body 60a having a bottomed cylindrical shape; and a first flange 62a covering the entire circumference outward from the upper end of the first optical member body 60a prominent. In the first optical member 6a, a first multi-lens 5a is formed on the bottom wall 61a at the lower end of the first optical member body 60a. The first optical member 6a is arranged such that the first flange 62a overlaps the lower end surfaces of the four first walls 84 of the base 8.

As shown in FIG. 1, the second optical member 6b includes: a second optical member body 60b having a bottom box shape; and a second flange 62b protruding outward from the upper end of the second optical member body 60b. The peripheral wall of the second optical member main body 60b, viewed from the base 8 side, has a C-shape that is open on the first optical member 6a side. In the second optical member 6b, a second multi-lens 5b is formed on the bottom wall 61b at the lower end of the second optical member body 60b. The second optical member 6b is arranged so that the second flange 62b overlaps the lower end surface of the second wall 85 of the base 8.

In the first multi-lens 5a, the first surface 501a (refer to FIG. 4) in which infrared rays from the outside (detection area 11) enter is composed of a group of plural incident surfaces of the first lenses 50a. The second surface 502a (see FIG. 4) in which the infrared rays are emitted from the first multi-lens 5a is composed of a group of plural emission surfaces of the plurality of first lenses 50a.

The plurality of first lenses 50a of the first multi-lens 5a are respectively condenser lenses, and are composed of convex lenses. Here, each of the convex lenses constituting the plurality of first lenses 50a is preferably an aspheric lens from the viewpoint of making the aberration smaller.

In the first multi-lens 5a, a plurality of (30) first lenses 50a are arranged separately in a plurality of rows (three rows) having different distances from the optical axis 39a of the first light receiving element 30a. Here, in the first multi-lens 5a, as shown in FIG. 8, a plurality of (30) first lenses 50a are separately arranged in a first imaginary circle C1, a second imaginary circle C2, and a third imaginary circle having different radii. Circle C3. The radius of the first imaginary circle C1, the second imaginary circle C2, and the third imaginary circle C3 become larger in the above order. The first multi-lens 5a is provided with four first lenses 50a on the first imaginary circle C1, ten first lenses 50a on the second imaginary circle C2, and sixteenth lenses on the third imaginary circle C3 1 lens 50a.

The first multi-lens 5a is preferably designed such that the focal points on the first light-receiving element 30a side of each of the plurality of first lenses 50a become the same position. The first multi-lens 5a is preferably configured such that infrared rays transmitted through the plurality of first lenses 50a respectively enter the window material 333 of the first infrared sensor 3a directly.

The infrared rays to be controlled by the plurality of first lenses 50a of the first multi-lens 5a are, for example, infrared rays in the wavelength range of 5 μm to 25 μm.

In the second multi-lens 5b, the first surface 501b (refer to FIG. 4) in which infrared rays from the outside (detection area 11) enter is composed of a group of plural incident surfaces of the second lenses 50b. In the second multi-lens 5b, the second surface 502b (see FIG. 4) from which infrared rays are emitted is composed of a group of plural emission surfaces of the plurality of second lenses 50b.

The plurality of second lenses 50b of the second multi-lens 5b are respectively condenser lenses, and are composed of convex lenses. Here, the convex lenses constituting the plurality of second lenses 50b are aspheric lenses, respectively. The plurality of second lenses 50b are preferably Fresnel lenses from the viewpoint of reducing the wall thickness.

In the second multi-lens 5b, plural (15) second lenses 50b are arranged separately in plural rows (three rows) having different distances from the optical axis 39a of the first light receiving element 30a. Here, in the second multi-lens 5b, as shown in FIG. 8, a plurality of (15) second lenses 50b are separately arranged in the fourth virtual circle C4, the fifth virtual circle C5, and the sixth virtual circle having different radii. Round C6. The radius of the fourth virtual circle C4, the fifth virtual circle C5, and the sixth virtual circle C6 become larger in the above order. The radius of the fourth virtual circle C4 is larger than the radius of the third virtual circle C3. The centers of the first virtual circle C1 to the sixth virtual circle C6 are the same. In the second multi-lens 5b, five second lenses 50b are arranged on the fourth virtual circle C4, seven second lenses 50b are arranged on the fifth virtual circle C5, and three lenses are arranged on the sixth virtual circle C6 The second lens 50b. In the second multi-lens 5b, regarding the two to three second lenses 50b arranged in the same radial direction common to the first imaginary circle C1 to the sixth imaginary circle C6, if it is further away from the first imaginary circle C1 to the sixth imaginary circle The second lens 50b at the center common to the circle C6 has a larger lens area.

The second multi-lens 5b is preferably designed such that the focal points on the second light receiving element 30b side of each of the plurality of second lenses 50b are at the same position. The second multi-lens 5b is preferably configured such that infrared rays transmitted through the plurality of second lenses 50b respectively enter the window material 333 of the second infrared sensor 3b directly.

The infrared rays to be controlled by the plural second lenses 50b of the second multi-lens 5b are, for example, infrared rays in the wavelength range of 5 μm to 25 μm.

The material of the first multi-lens 5a and the second multi-lens 5b is, for example, polyethylene. More specifically, the material of the first multi-lens 5a is polyethylene added with white pigment or black pigment. As the white pigment, for example, inorganic pigments such as titanium oxide are preferably used. As the black pigment, for example, fine particles such as carbon black are preferably used. The first multi-lens 5a and the second multi-lens 5b can be formed by a molding method, for example. As the molding method, for example, an injection molding method, a compression molding method, or the like can be used.

The infrared detection device 100 is, for example, assumed to be used on a ceiling or the like so that the center line 110 (refer to FIG. 4) of the detection area 11 faces vertically downward. In other words, in one usage form, the infrared detection device 100 is assumed to be arranged so that the light receiving surface of the first light receiving element 30a faces vertically downward. The detection area 11 is a three-dimensional area with a quadrangular pyramid shape. The detection area 11 is a square in a horizontal plane perpendicular to the center line 110.

The solid angle of the detection area 11 of the infrared detection device 100 is defined by the first light receiving unit 2a and the plurality of second light receiving units 2b. In the infrared detection device 100, a plurality of (90) small detection regions 13 (refer to FIGS. 6B and 7) of the detection region 11 are divided, respectively with the first light receiving unit 2a and the plurality of (4) second light receiving Any correspondence of unit 2b. 6B is a schematic diagram of the detection area 11 of the infrared detection device 100 in an imaginary plane 120 (for example, a floor surface) perpendicular to the center line 110 of the detection area 11. In addition, FIG. 7 is a schematic diagram of one of the plurality of small detection areas 13 of the infrared detection device 100 in a virtual plane 120 (for example, a floor surface). The detection area 11 includes a plurality of (90) small detection areas 13. A plurality of (90) small detection areas 13 respectively including a plurality (4) of small detection areas 14 corresponding to the plurality (4) of detection portions of the light receiving element 30 (refer to FIG. 7) . The plurality of micro detection areas 14 are respectively located in different directions when viewed from the light receiving element 30. The plurality of micro detection areas 14 are respectively obliquely quadrangular pyramid shaped. The solid angle of each of the plurality of micro detection areas 14 is smaller, and the solid angle of the smaller detection area 13 is smaller. In other words, the small detection area 14 and the smaller detection area 13 are narrower. The tiny detection area 14 is a three-dimensional area formed when the infrared beam incident on the detection portion of the first light receiving element 30a through the first lens 50a is extended in the direction opposite to the traveling direction of infrared rays, or it will pass through The three-dimensional area formed by the two lenses 50b and the infrared beam incident on the detection portion of the second light receiving element 30b is extended in the direction opposite to the traveling direction of infrared rays. In other words, the minute detection area 14 is a three-dimensional area through which the infrared beam used for imaging on the light receiving surface of the detection portion of the light receiving element 30 can pass. The small detection area 14 can be estimated by, for example, simulation results using ray tracing analysis software. The plurality of minute detection regions 14 can be regarded as having polarities corresponding one-to-one with the first electrode of the detection unit. The detection area 11, each small detection area 13, and each minute detection area 14 are optically defined 3-dimensional areas, not actually 3-dimensional areas that are visible to the naked eye. The small detection area 13 also depends on the size and shape of the window material 333 of the infrared sensor 3 (refer to FIG. 5), the opening shape of the window hole 3322, and the like.

In the infrared detection device 100, the plural (30) first lenses 50a of the first light receiving unit 2a correspond to one of the plural (90) small detection regions 13, respectively. In other words, the first light receiving unit 2a corresponds to 30 small detection areas 13 out of 90 small detection areas 13. In addition, in the infrared detection device 100, the plural (15) second lenses 50b of each of the second (4) second light receiving units 2b are respectively different from the plural (90) small detection areas 13 of the second lens 50b. One small detection area corresponds to 13. In other words, four second light-receiving units 2b correspond to 15 small detection areas 13 out of 90 small detection areas 13, respectively. That is, in the infrared detection device 100, the number of small detection areas 13 (30) corresponding to the first light receiving unit 2a is more than the number of small detection areas 13 corresponding to the plurality of second light receiving units 2b, respectively (15) More.

As described above, the infrared detection device 100 includes a signal processing unit 9 that determines whether or not someone is present in the detection area 11 based on the output signals of the first light receiving element 30a and the plurality of second light receiving elements 30b. The signal processing unit 9 performs, for example, synchronous detection that extracts the synchronous components of the output signals of the plurality of light-receiving elements 30, and determines whether someone exists in the detection area 11 based on the result of the synchronous detection. The signal processing unit 9 can be configured by, for example, a multiplier or a comparator for performing synchronous detection. Here, the components of the signal processing unit 9 are mounted on the circuit board 7. The components of the signal processing unit 9 are arranged on the second surface 72 side of the circuit board 7. The signal processing unit 9 may also include the IC elements of the plurality of infrared sensors 3 described above.

In the case where the area of the incident surface of the plural lenses of the multi-lens is fixed, if the lens has a larger optical axis angle with the optical axis of the light receiving element among the plural lenses, there is a loss of incident infrared rays The tendency to become larger. Therefore, like the hot-wire type human body sensor described in Document 1, the infrared detection device in which only one multi-lens forms the detection area has a tendency to decrease the sensitivity on the outermost side of the detection area.

In contrast, in the infrared detection device 100 of this embodiment, as shown in FIGS. 4 and 6B, the detection area 11 is divided into a central area 11a and a peripheral area 11b. The central area 11a, corresponding to the first light receiving unit 2a, includes 30 small detection areas 13 out of 90 small detection areas 13. The peripheral area 11b, corresponding to the plurality of second light receiving units 2b, includes 60 small detection areas 13 out of 90 small detection areas 13. As shown in FIG. 6B, the central area 11 a is a circular area on the virtual plane 120. As shown in FIG. 6B, the peripheral region 11b is a region where the central region 11a is removed from the square region including the central region 11a (a frame-shaped region whose outer periphery is square and inner circle is circular) on the virtual plane 120. In the infrared detection device 100, compared to the lens area of the first lens 50a corresponding to each small detection area 13 included in the central area 11a, the second lens corresponding to each small detection area 13 included in the peripheral area 11b The lens area of 50b is larger.

As shown in FIG. 4, when the direction along the arrangement direction of the first light-receiving element 30a and the second light-receiving element 30b is the predetermined direction D1, in FIG. 9, in the small detection area 13 of the central area 11a, according to The distance between the small detection areas 13 determined by the combination of each two adjacent small detection areas 13 in the prescribed direction D1 is the distance L1. In addition, in FIG. 9, the interval between the small detection areas 13 in the small detection areas 13 of the peripheral area 11b, which is determined according to the combination of each adjacent two small detection areas 13 in the prescribed direction D1, is Distance L2. Here, the average value of a plurality of (the number of combinations of two small detection areas 13 adjacent in the predetermined direction D1 in the peripheral area 11b) is greater than the average of the plurality of (the two adjacent in the predetermined direction D1 in the central area 11a) The number of combinations of each small detection area 13) The average value of the distance L1 is larger.

The infrared detection device 100 of the present embodiment described above includes the light receiving system 1 that receives infrared rays from the detection area 11. The light receiving system 1 includes a first light receiving unit 2a and a plurality of second light receiving units 2b. The first light receiving unit 2a includes a first light receiving element 30a and a first multi-lens 5a. The first multi-lens 5a has a plurality of first lenses 50a that concentrate infrared rays to the first light receiving element 30a. The plurality of second light-receiving units 2b include a second light-receiving element 30b and a second multi-lens 5b, respectively. The second multi-lens 5b has a plurality of second lenses 50b that condense infrared rays to the second light receiving element 30b. In the infrared detection device 100, the plurality of small detection areas 13 that divide the detection area 11 correspond to any of the first light receiving unit 2a and the plurality of second light receiving units 2b, respectively. In the infrared detection device 100, the plurality of first lenses 50a of the first light receiving unit 2a correspond to one of the plurality of small detection regions 13 respectively. In the infrared detection device 100, the plurality of second lenses 50b of each of the plurality of second light receiving units 2b correspond to one of the plurality of small detection regions 13, respectively. The optical axis 39b of the second light-receiving element 30b of each of the plurality of second light-receiving units 2b is inclined in different directions with respect to the optical axis 39a of the first light-receiving element 30a. The number of the first group of small detection areas 13 in the plurality of small detection areas 13 corresponding to the first light receiving unit 2a is compared with the number of the second light receiving units 2b in the plurality of small detection areas 13 respectively The second group of small detection areas 13 has a larger number.

With the above configuration, the infrared detection device 100 can suppress the unevenness of the sensitivity in the detection area 11. Here, the infrared detection device 100 can achieve the lens area of the second lens 50b corresponding to the small detection area 13 having a relatively large slope with respect to the optical axis 39a of the first light-receiving element 30a by the above-mentioned configuration, which is better than that of the first lens 50b. The first lens 50a of the light receiving element 30a having a relatively small slope of the optical axis 39a has a larger lens area. Thereby, the infrared detection device 100 can suppress the unevenness of the sensitivity in the detection area 11. In short, the infrared detection device 100 can pursue the uniformity of the sensitivity in the detection area 11.

In addition, compared with the case where the diameter of the multi-lens of the hemispherical shape is increased in the above-mentioned hot-wire type human body sensor to increase the number of rows of the lens to expand the detection area, the infrared detection device 100 can suppress detection The sensitivity on the outermost peripheral side of the area 11 decreases. In other words, the infrared detection device 100 can increase the viewing angle but suppress the decrease in sensitivity on the outermost periphery side of the detection area 11, and can increase the viewing angle but suppress unevenness in sensitivity in the detection area 11. "View angle" refers to the divergence angle of the detection area 11 of the infrared detection device 100.

In the infrared detection device 100, the plurality of second multi-lenses 5b are preferably arranged in the outer circumferential direction of the first multi-lens 5a so as to surround the first multi-lens 5a. As a result, the infrared detection device 100 can further expand the detection area 11 in a substantially full direction perpendicular to the optical axis 39a of the first light receiving element 30a.

In the infrared detection device 100, the plural second light receiving units 2b are preferably at least three second light receiving units 2b. Thus, in the infrared detection device 100, for example, when the detection area 11 is a quadrangular pyramid-shaped area, compared with the case where only one first light receiving unit 2a and two second light receiving units 2b are provided, each The design of the second light receiving unit 2b becomes simple.

In the infrared detection device 100, it is preferable to arrange a plurality of first lenses 50a separately in at least two rows at different distances from the optical axis 39a of the first light receiving element 30a; separate a plurality of second lenses 50b The distance from the optical axis 39 of the first light-receiving element 30a is at least two different rows. When the direction along the arrangement direction of the first light-receiving element 30a and the second light-receiving element 30b is the predetermined direction D1, in the second group of small detection regions 13, each of the two adjacent small areas in the predetermined direction D1 The average value of the distance L2 between the small detection areas 13 determined by the combination of the detection areas 13 should be better than that of the first group of small detection areas 13 according to the two adjacent small detection areas in the specified direction D1 The average value of the distance L1 between the small detection areas 13 determined by the combination of 13 is greater. Thereby, the infrared detection device 100 can increase the lens area of the second lens 50b by reducing the number of small detection areas 13 corresponding to the second light receiving unit 2b, and can further suppress detection Uneven sensitivity in the area 11.

In the infrared detection device 100, both the first light receiving element 30a and the second light receiving element 30b are preferably thermoelectric elements. As a result, the infrared detection device 100 is easier to detect the motion of an object that emits infrared light (such as a human body) than when the first light receiving element 30a and the second light receiving element 30b are thermopiles, resistance heat meters, or the like.

The infrared detection device 100 preferably further includes a signal processing unit 9. The signal processing unit 9 preferably determines whether or not someone is present in the detection area 11 based on the output signals of the first light receiving element 30a and the plurality of second light receiving elements 30b. In this way, the infrared detection device 100 can be used as a human detection device.

The first light-receiving element 30a and the second light-receiving element 30b are not limited to a group of four thermoelectric elements. For example, they may be a group of two thermoelectric elements or a monolithic thermoelectric element. In addition, the shape and arrangement of the detection portion of the thermoelectric element are not particularly limited. For example, the thermoelectric element may have a configuration in which four detection sections are arranged in a 1×4 array on one thermoelectric substrate. In this case, each of the four detection sections has a rectangular shape in plan view. In addition, adjacent detection sections are connected in antiparallel to each other. In addition, the thermoelectric element is not limited to a structure provided with a pyroelectric substrate. For example, it may be formed on the surface of a silicon substrate with an electrical insulating film formed in the order of back electrode, pyroelectric thin film, and surface electrode. The wafer that constitutes the detection section. These wafers can be formed using micromachining technology and thermoelectric thin film formation technology, for example.

The infrared detection device 100 is not limited to human detection, and can also be used for other purposes such as gas detection.

The infrared detection device 100 can be used, for example, in wiring appliances, equipment, and the like. Examples of equipment include lighting fixtures, lighting devices, televisions, personal computers, air conditioners, humidifiers, refrigerators, photocopiers, digital signage boards, digital photo frames, urinals, vending machines, ticket vending machines, and cash dispensers. , Gas sensors, gas analysis devices, etc.

1‧‧‧Light receiving system 100‧‧‧Infrared detection device 11‧‧‧ Detection area 11a‧‧‧Central area 11b‧‧‧ Peripheral area 110‧‧‧Center line 120‧‧‧Imaginary plane 13‧‧‧small Detection area 14‧‧‧Miniature detection area 2a‧‧‧First light receiving unit 2b‧‧‧Second light receiving unit 3‧‧‧Infrared sensor 3a‧‧‧First infrared sensor 3b‧‧ ‧Second infrared sensor 30‧‧‧Light receiving element 30a‧‧‧First light receiving element 30b‧‧‧Second light receiving element 33‧‧‧Package 331‧‧‧Pedestal 332‧‧‧Cover 3321‧ ‧‧Front wall 3322‧‧‧Window hole 333‧‧‧Window material 334‧‧‧Lead terminals 39, 39a, 39b ‧‧‧ Optical axis 5a‧‧‧First multi-lens 5b‧‧‧ Second multi-lens 50a‧ ‧‧First lens 50b‧‧‧Second lens 501a, 501b‧‧‧First face 502a, 502b‧‧‧Second face 6a‧‧‧First optical member 6b‧‧‧ Second optical member 60a‧‧‧ 1st optical member body 60b ‧‧‧ 2nd optical member body 61a, 61b ‧‧‧ bottom wall 62a ‧‧‧ 1st flange 62b ‧‧‧ 2nd flange 7‧‧‧ circuit board 71‧‧‧ 1st Face 72‧‧‧Second face 74‧‧‧‧Pin through hole 8‧‧‧Base part 801‧‧‧Central part 802‧‧‧Circular part 81a‧‧‧First spacer part 81b‧‧‧Second spacer Part 811a, 811b ‧‧‧ Surface 82a, 82b ‧ ‧ ‧ hole 83 ‧ ‧ ‧ shading wall 84 ‧ ‧ ‧ 1st wall 85 ‧ ‧ ‧ second wall 9 ‧ ‧ ‧ signal processing section C1 ~ C6 ‧ ‧ ‧ imaginary circle D1‧‧‧ prescribed direction L1, L2‧‧‧ distance

FIG. 1 is an exploded perspective view of an infrared detection device according to an embodiment of the present invention. FIG. 2A is a perspective view of the infrared detection device viewed from above; FIG. 2B is a perspective view of the infrared detection device viewed from below. 3A is a bottom view of the light receiving system of the infrared detection device; FIG. 3B is a bottom view of the left half of the light receiving system of the infrared detection device. 4 is a cross-sectional view of the infrared detection device. 5 is a perspective view of an infrared sensor including a light-receiving element of the infrared detection device. 6A is a top view of the light receiving system of the infrared detection device; FIG. 6B is an explanatory view of the detection area of the infrared detection device. 7 is an explanatory diagram of a small detection area of the detection area of the infrared detection device. 8 is an explanatory diagram of the first multi-lens and the second multi-lens of the infrared detection device. 9 is an explanatory diagram of the detection area of the infrared detection device.

11‧‧‧ detection area

11a‧‧‧Central area

11b‧‧‧ Surrounding area

120‧‧‧Imaginary plane

13‧‧‧Small detection area

5a‧‧‧The first multi-lens

50a‧‧‧1st lens

50b‧‧‧2nd lens

6a‧‧‧First optical component

6b‧‧‧The second optical component

61a, 61b ‧‧‧ bottom wall

Claims (4)

An infrared detection device is provided with a light receiving system that receives infrared rays from a detection area, characterized in that the light receiving system includes a first light receiving unit and a plurality of second light receiving units; the first light receiving unit includes A first light-receiving element and a first multi-lens, the first multi-lens has a plurality of first lenses condensing infrared rays to the first light-receiving element; the plurality of second light-receiving units, each including a second light-receiving element An element and a second multi-lens, the second multi-lens has a plurality of second lenses condensing infrared rays to the second light-receiving element; a plurality of small detection areas dividing the detection area, and the first light respectively The receiving unit corresponds to any one of the plurality of second light receiving units; the plurality of first lenses of the first light receiving unit respectively correspond to one of the plurality of small detection areas; Each of the plurality of second lenses of the plurality of second light receiving units corresponds to one of the plurality of small detection areas; the second of each of the plurality of second light receiving units The optical axis of the light-receiving element is inclined in different directions with respect to the optical axis of the first light-receiving element; the first group of small detections corresponding to the first light-receiving unit in the plurality of small detection areas The number of regions is greater than the number of the second group of small detection regions in the plurality of small detection regions corresponding to the plurality of second light receiving units; the plurality of second light receiving units is at least 3 Second light-receiving units; the plurality of second multi-lenses are arranged in the outer circumferential direction of the first multi-lens in such a way as to surround the first multi-lens; and the area of each second lens is compared to each of the first The area of the lens is larger. For example, the infrared detection device according to item 1 of the patent application, wherein the plurality of first lenses are separately arranged in at least two rows at different distances from the optical axis of the first light-receiving element; the plurality of first lenses 2 lenses, arranged separately in at least two rows with distances different from the optical axis of the first light receiving element; the direction along the arrangement direction of the first light receiving element and the second light receiving element is When specifying the direction, in the second group of small detection areas, the average distance between the small detection areas determined according to the combination of each adjacent two small detection areas in the specified direction is lower than that of the first In the group small detection area, the average value of the distance between the small detection areas determined according to the combination of each adjacent two small detection areas in the specified direction is larger. For example, in the infrared detection device of claim 1 or 2, the first light-receiving element and the second light-receiving element are both thermoelectric elements. For example, the infrared detection device according to item 1 or 2 of the patent application scope further includes a signal processing unit that determines whether to output the signal according to the respective output signals of the first light receiving element and the plurality of second light receiving elements Someone exists in the detection area.

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