CN108780005B

CN108780005B - Infrared detection device

Info

Publication number: CN108780005B
Application number: CN201780019514.3A
Authority: CN
Inventors: 上津智宏; 桥本裕介
Original assignee: Panasonic Intellectual Property Management Co Ltd
Current assignee: Panasonic Intellectual Property Management Co Ltd
Priority date: 2016-03-22
Filing date: 2017-02-27
Publication date: 2021-07-06
Anticipated expiration: 2037-02-27
Also published as: TW201734968A; TWI632531B; WO2017163760A1; JP2017173050A; JP6685012B2; CN108780005A

Abstract

The invention can provide an infrared detection device capable of enlarging a detection area while suppressing sensitivity to be low. The infrared detection device (100) includes an infrared detection element (2) and a multi-lens element (30), and further includes a1 st mirror portion (4) and a2 nd mirror portion (5). The 1 st mirror section (4) is disposed above the infrared detection element (2) between the infrared detection element (2) and the multi-lens element (30), and reflects a part of the infrared rays that have passed through the multi-lens element (30) and have not been directly incident on the infrared detection element (2). The 2 nd mirror part (5) is disposed below the infrared detection element (2) between the infrared detection element (2) and the multi-lens element (30) and reflects the infrared rays reflected by the 1 st mirror part (4) toward the infrared detection element (2).

Description

Infrared detection device

Technical Field

The present invention relates to an infrared detection device, and more particularly, to an infrared detection device including a multi-lens element.

Background

An infrared detection device is known, for example, as an infrared human body detector that detects infrared rays emitted from a human body to determine whether or not a human body is present in a detection area (patent document 1).

The infrared human body detector described in patent document 1 includes: an infrared sensor for detecting infrared rays emitted from a human body; a plurality of lenses arranged in front of the light receiving surface of the infrared sensor; and a reflecting mirror which turns a part of infrared rays passing through lenses located at both ends among the lenses arranged in a line, which are not directly incident on the light receiving surface of the infrared sensor, and which faces the light receiving surface of the infrared sensor.

In the infrared human body detector, a part of the infrared rays directly emitted to the infrared sensor through the lens is shielded by the reflecting mirror, thereby reducing the sensitivity.

[ Prior art documents ]

[ patent document ]

Patent document 1: japanese laid-open patent publication No. 2000-234955

Disclosure of Invention

In the field of infrared detection devices, there is a need to further enlarge the detection area without reducing sensitivity.

The invention aims to provide an infrared detection device which can restrain the reduction of sensitivity and can further enlarge the detection area.

An infrared detection device according to an aspect of the present invention includes an infrared detection element and a multi-lens element. The multi-lens element is provided with a plurality of lenses for respectively condensing infrared rays on the infrared detection element. The infrared detection device further includes a1 st mirror portion and a2 nd mirror portion. The 1 st reflector is disposed above the infrared detection element between the infrared detection element and the multi-lens element. The 1 st reflecting mirror part is used for reflecting a part of infrared rays which pass through the multi-lens element and are not directly incident to the infrared detection element. The 2 nd mirror portion is disposed below the infrared detection element between the infrared detection element and the multi-lens element. The 2 nd reflector is used for reflecting the infrared ray reflected by the 1 st reflector towards the infrared ray detection element.

Drawings

Fig. 1 is a longitudinal sectional view of an infrared detection device according to an embodiment of the present invention.

Fig. 2 is a front view of a main part of the infrared detection device as described above.

Fig. 3A is a perspective view of a main part of the infrared detection device as above viewed from the lower side. Fig. 3B is a perspective view of the essential part of the infrared detection device as described above, as viewed from above.

Fig. 4 is a perspective view of the essential part of the infrared detection device as described above, viewed from a direction different from that shown in fig. 3B.

Fig. 5A is a front view of the infrared detection element in the infrared detection device described above. Fig. 5B is a sectional view taken along line G-G of fig. 5A.

Fig. 6 is a schematic explanatory view of a light receiving surface of an infrared detection element in the infrared detection device as described above.

Fig. 7A is a front view of the multi-lens element in the infrared detection device as above. Fig. 7B is a rear view of the multi-lens element in the infrared detection device as described above.

Fig. 8A is an X-X sectional view of fig. 7A. Fig. 8B is a cross-sectional view taken along line Y-Y of fig. 7A.

Fig. 9 is a cross-sectional view of a main part of the infrared detection device as above.

FIG. 10 is a block diagram of the infrared detecting device.

Fig. 11A is a front view of a main part of the infrared detection device as described above. Fig. 11B is a cross-sectional view as viewed from the lower side.

Fig. 12 is a perspective view of the infrared detection device as described above.

Detailed Description

The drawings described in the embodiments below are schematic views, and the size and thickness of each component in the drawings do not necessarily reflect the actual dimensional ratio.

[ embodiment ]

The infrared detection device 100 according to the present embodiment will be described below with reference to fig. 1 to 12.

The infrared detection device 100 includes an infrared detection element 2 and a multi-lens element 30. The multi-lens element 30 includes a plurality of lenses 31 each for condensing infrared rays to the infrared detection element 2. The infrared detection device 100 further includes a1 st mirror unit 4 and a2 nd mirror unit 5. The 1 st mirror 4 is disposed above the infrared detection element 2 between the infrared detection element 2 and the multi-lens element 30. The 1 st mirror portion 4 is configured to reflect a part of the infrared rays that have passed through the multi-lens element 30 and are not directly incident on the infrared detection element 2. The 2 nd mirror portion 5 is disposed below the infrared detection element 2 between the infrared detection element 2 and the multi-lens element 30. The 2 nd mirror portion 5 is configured to reflect the infrared ray reflected by the 1 st mirror portion 4 toward the infrared ray detection element 2. The infrared detection device 100 having the above-described configuration can further expand the detection region while suppressing a decrease in sensitivity. More specifically, in the infrared detection device 100, a part of the infrared rays from below the infrared detection device 100, which pass through the multi-lens element 30 and do not directly enter the infrared detection element 2, is reflected by the 1 st mirror portion 4, then reflected by the 2 nd mirror portion 5, and then enters the infrared detection element 2. Thereby, the infrared detection device 100 can further expand the detection region downward as compared with the case where the 1 st mirror portion 4 and the 2 nd mirror portion 5 are not included. In other words, the infrared detection device 100 can expand the viewing angle at the lower side of the vertical direction. The "viewing angle" is defined as the outward expansion of the detection area of the infrared detection device 100. In the infrared detection device 100, the infrared rays that should be directly incident on the infrared detection element 2 by the multi-lens element 30 are not shielded by the 1 st mirror portion 4 and the 2 nd mirror portion 5, and thus the reduction in sensitivity can be suppressed.

The infrared detection device 100 preferably includes a package 6 housing the infrared detection element 2. The package 6 has a window member 63 that transmits infrared rays. The window member 63 is disposed in front of the infrared detection element 2. The multi-lens element 30 is preferably configured such that infrared rays transmitted through each of the plurality of lenses 31 are directly incident on the window member 63.

The package 6 includes: a package body 60 housing the infrared detection element 2; a window member 63 for closing a window hole 601 formed in front of the infrared detection element 2 in the package body 60; and a plurality (e.g., 3) of terminals. The package 6 is a so-called can package (can package). The can package is also called a metal package (metal package). The window member 63 is an infrared-transmitting member. For example, a silicon substrate, a germanium substrate, or the like can be used as the infrared ray transmitting member. The infrared ray transmitting member preferably includes an appropriate optical filter film or reflection preventing film.

The infrared detection device 100 can be used, for example, as a human body detection device for detecting infrared rays emitted from a human body and outputting a human body detection signal.

The infrared detection device 100, as shown in fig. 10, preferably includes a signal processing circuit 7 in addition to the infrared detection element 2. The signal processing circuit 7 preferably includes an amplifying circuit 71, a band filter 72, a comparing circuit 73, and an output circuit 74.

In the signal processing circuit 7, the amplifier circuit 71, the band filter 72, the comparator circuit 73, and the output circuit 74 are preferably integrated in 1 IC device. In the infrared detection device 100, it is preferable that a substrate on which a component assembly (for example, the IC device described above) of the infrared detection element 2 and the signal processing circuit 7 is mounted is housed in the package 6. The substrate may be, for example, an MID (Molded Interconnect Devices) substrate, a component built-in substrate, a printed circuit board, or the like.

The amplifier circuit 71 is a circuit for amplifying an output signal of the infrared detection element 2. The amplifier circuit 71 may be constituted by, for example, a current-voltage conversion circuit and a voltage amplifier circuit. The current-voltage conversion circuit is used for converting the current signal, which is the output signal of the infrared detection element 2, into a voltage signal. The voltage amplifying circuit is used for amplifying and outputting a voltage signal with a predetermined frequency bandwidth (for example, 0.1 Hz-10 Hz) in the voltage signal output by the current-voltage conversion circuit.

The band filter 72 removes an unnecessary frequency component, which is regarded as noise, from the voltage signal amplified by the amplifier circuit 71.

The comparison circuit 73 is configured to compare the voltage signal amplified by the amplification circuit 71 with a preset threshold value to determine whether the voltage signal exceeds the threshold value. The comparator circuit 73 can be constituted by a comparator or the like, for example.

The output circuit 74 takes the human body detection signal as an output signal when the voltage signal in the comparison circuit 73 is determined to exceed the threshold value. The "human body detection signal" may be, for example, a pulse signal that reaches a high level at a certain time. Therefore, the output of the output circuit 74 is low when there is no output of the human body detection signal, and high when there is an output of the human body detection signal.

The infrared detection device 100 is not limited to the case where the components of the signal processing circuit 7 are housed in the package 6, and may be mounted on a circuit board with a part or all of the components of the signal processing circuit 7 being outside the package 6. The circuit substrate may be constituted by, for example, a printed circuit board.

The infrared detection device 100 is applicable to, for example, a wiring tool. The wiring tool may include, for example, a power supply terminal, a load terminal, and a switching element connected between the power supply terminal and the load terminal, and is a buried type wiring tool used by connecting an external circuit between the power supply terminal and the load terminal. The external circuit may be, for example, a series circuit of a power supply (e.g., a commercial power supply) and a control target load. The wiring device can control the ON/OFF of the load by performing ON/OFF control of the switching element depending ON whether or not a human body detection signal is received from the infrared detection device 100. The control target load may be, for example, a lighting load, a ventilation fan, or the like.

When the load to be controlled of the wiring device is, for example, a lighting load, it is preferable to set the detection area of the infrared detection device 100 in a room, a corridor, an entrance, or the like in which the lighting load is installed. Thus, the wiring device can turn on or off the lighting load according to whether or not a person is present in a room, a corridor, an entrance, or the like. The height from the ground to the wiring tool is, for example, 1.2 m. The infrared detection device 100 can detect not only the front direction but also a person located right below the near side.

The components of the infrared detection device 100 will be described in further detail below.

The infrared detection element 2 is, for example, a pyroelectric element of a four-line array type (quad type). In the infrared detection element 2, for example, as shown in fig. 5A, 5B, and 6, 4 detection portions 24 are formed on 1 pyroelectric substrate 23.

In the

infrared detection element

2, 4 detection units 24 are arranged in a2 × 2 array (matrix) on 1 pyroelectric substrate 23. In other words, in the

infrared detection element

2, 4 detection units 24 are arranged in a2 × 2 matrix.

The pyroelectric substrate 23 has a square shape in plan view. The pyroelectric substrate 23 is a substrate having a pyroelectric property. The pyroelectric substrate 23 may be formed of, for example, a single crystal of LiTaO₃A substrate.

The shape of each of the plurality of detection units 24 is a square in plan view. In the infrared detection element 2, the center positions of the detection portions 24 are 4 corners of a virtual square VR1 (see fig. 6) located inside the outer peripheral line 230 of the pyroelectric substrate 23 in the center portion of the pyroelectric substrate 23.

Each of the 4 detection units 24 is a capacitor, and includes: a surface electrode 25 formed on the surface 231 of the pyroelectric substrate 23; a back electrode 26 formed on the back surface 232 of the pyroelectric substrate 23; and a portion 233 sandwiched between the front surface electrode 25 and the back surface electrode 26 in the pyroelectric substrate 23. In fig. 5A, the polarities of the surface electrodes 25 on the multi-lens element 30 side are denoted by "+" and "-" signs for each of the 4 detection units 24. The light receiving surface 24a of each of the 4 detectors 24 is the surface of the surface electrode 25.

The infrared detection element 2 has a light-receiving surface 20 (see fig. 6) having a rectangular shape in plan view, and includes a surface electrode 25 of each of the 4 detection portions 24. "rectangular" herein refers to a right-angled quadrilateral, i.e., a rectangle or square. In fig. 6, a square light-receiving surface 20 is taken as an example of the rectangular light-receiving surface 20. The light-receiving surface 20 of the infrared detection element 2 is a surface of a region surrounded by the outer peripheral line of the convex polygon VR2 including the light-receiving surfaces 24a of the 4 detection portions 24. The convex polygon VR2 in fig. 6 is a rectangle. A normal line passing through the center 200 of the light receiving surface 20 of the infrared detection element 2 can be regarded as the optical axis of the infrared detection element 2.

In the infrared detection element 2, of the 4 detection portions 24 arranged in a2 × 2 matrix, 2 detection portions 24 arranged along the direction of the 1 st diagonal line 201 of the rectangular light receiving surface 20 are connected in parallel with each other. In the

infrared detection element

2, 2 detection units 24 arranged in parallel with each other in the direction of the 2 nd diagonal line 202 of the rectangular light receiving surface 20 are provided. In the

infrared detection element

2, 2 detection units 24 arranged in the row direction are connected in reverse parallel to each other, and 2 detection units 24 arranged in the column direction are connected in reverse parallel to each other. The "row direction" in this specification is defined as the 1 st direction (left-right direction in fig. 6) along 1 of the 4 sides of the rectangular light-receiving surface 20. The "column direction" is defined as a2 nd direction (vertical direction in fig. 6) orthogonal to the thickness direction and the 1 st direction of the infrared detection element 2.

In the infrared detection element 2, the polarities of the surface electrodes 25 of the 2 detection units 24 arranged along the 1 st diagonal line 201 are the same. In the infrared detection element 2, the polarities of the surface electrodes 25 of the 2 detection units 24 arranged in the row direction are different from each other. In the infrared detection element 2, the polarities of the surface electrodes 25 of the 2 detection units 24 arranged in the column direction are different from each other.

The infrared detection element 2 is preferably arranged such that the direction along the 1 st diagonal line 201 of the rectangular light receiving surface 20 is the left-right direction. In this case, the state (see fig. 2) when the infrared detection element 2 is rotated by 45 ° clockwise (as viewed from the front of the light receiving surface 20) with reference to the state shown in fig. 5A and 6 is set as the state when facing the multi-lens element 30.

The multi-lens element 30 is disposed in front of the infrared detection element 2 as shown in fig. 5A. The "front of the infrared detection element 2" is defined as the front in the direction along the normal line passing through the center 200 of the light receiving surface 20 of the infrared detection element 2.

The multi-lens element 30 is preferably designed such that the respective focal points of the plurality of lenses 31 on the infrared detection element 2 side fall at the same position. In fig. 9, a path of infrared rays incident on the infrared detection element 2 through the multi-lens element 30 is schematically shown by a broken line.

The infrared ray to be controlled by each of the plurality of lenses 31 in the multi-lens element 30 is, for example, an infrared ray in a wavelength range of 5 μm to 25 μm.

The material of the multi-lens element 30 is, for example, polyethylene. In more detail, the material of the multi-lens element 30 is polyethylene to which a white pigment or a black pigment is added. The white pigment used may be preferably an inorganic pigment such as titanium oxide, plumbite (zinc oxide) or the like. The black pigment is preferably fine particles such as carbon black. The multi-lens element 30 can be formed, for example, by a molding method. The molding method may be, for example, injection molding, compression molding, or the like.

In the multi-lens element 30, each of the plurality of lenses 31 is a condenser lens configured by a convex lens. Each of the plurality of lenses 31 here is constituted by an aspherical lens. Each of the plurality of lenses 31 may be formed by a fresnel lens.

The 1 st surface 301 on which infrared rays are incident in the multi-lens element 30 is formed by a group of incident surfaces of the plurality of lenses 31. In the multi-lens element 30, the 2 nd surface 302 from which infrared rays are emitted is formed by a group of emission surfaces of the plurality of lenses 31. In the multi-lens element 30, a plurality of lenses 31 are arranged vertically and horizontally. In one example of the multi-lens element 30, 15 lenses 31 are arranged in a line in the upper side, and 13 lenses 31 are arranged in a line in the lower side.

The infrared detection device 100 includes an optical member 10 including a1 st mirror portion 4 and a2 nd mirror portion 5. The optical member 10 may be, for example, a member having a plating film provided on the surface of a synthetic resin molded product. The material of the synthetic resin molded product is, for example, ABS resin. The material of the plated film is preferably a material having a high reflectance with respect to infrared rays. The material of the plating film is, for example, aluminum, but is not limited thereto, and may be chromium or the like.

The optical member 10 includes a cylindrical portion 11, an upper protruding piece 12, and a lower protruding piece 13. The cylindrical portion 11 has a cylindrical shape surrounding the package 6. The upper projecting piece 12 projects in the axial direction from the upper portion of the 1 st end in the axial direction of the cylindrical body portion 11. The lower tab 13 protrudes in the axial direction from the lower portion of the 1 st end of the barrel portion 11. In the infrared detection device 100, the package 6 is preferably embedded in the optical member 10. With this, in the infrared detection device 100, the relative positional accuracy of the optical member 10 and the infrared detection element 2 can be improved. The 1 st mirror portion 4 is formed at the center in the left-right direction below the upper protruding piece 12. In this way, the 1 st mirror portion 4 is disposed above the infrared detection element 2. More specifically, the 1 st mirror portion 4 is disposed obliquely above the light receiving surface 20 of the infrared detection element 2 between the infrared detection element 2 and the multi-lens element 30. The 2 nd mirror portion 5 is formed on the upper surface of the lower protruding piece 13. In this way, the 2 nd mirror portion 5 is disposed below the infrared detection element 2. More specifically, the 2 nd mirror portion 5 is disposed obliquely below the light receiving surface 20 of the infrared detection element 2 between the infrared detection element 2 and the multi-lens element 30.

As shown in fig. 2, 3A and 3B, the optical member 10 preferably includes an upper protrusion 17 protruding upward from the outer peripheral surface and a lower protrusion 18 protruding downward at the 2 nd end in the axial direction of the barrel portion 11. The infrared detection device 100 preferably includes a dome-shaped housing 3 (see fig. 12) that has the multi-lens element 30 and covers the optical member 10. In this case, an upper slit 317 fitted into the upper projection 17 and a lower slit fitted into the lower projection 18 are preferably formed at the rear end edge of the outer cover 3. Accordingly, in the infrared detection device 100, the relative positional accuracy of the multi-lens element 30, the infrared detection element 2, and the optical member 10 can be improved.

The multi-lens element 30 has a C-shape when viewed from above (see fig. 8A and 9), and preferably covers the infrared detection element 2. Thereby, the horizontal viewing angle of the detection area can be enlarged in the infrared detection device 100. In the infrared detection device 100, the temperature change of the package 6 due to wind or the like is less likely to occur, and the fluctuation of the output signal of the infrared detection element 2 can be suppressed. Since the infrared detection device 100 includes the multi-lens element 30 and the dome-shaped cover 3 (see fig. 12) covering the optical member 10, it is not easy for a temperature change of the package 6 to occur due to wind or the like, and fluctuation of the output signal of the infrared detection element 2 can be suppressed.

If the infrared detection device 100 does not include the optical member 10, the detection area of the infrared detection device 100 is determined by a plurality of (e.g., 28) lenses 31 and a plurality of (e.g., 112) infrared light receiving paths defined by a plurality of (e.g., 4) detection units 24. Each of the plurality of infrared ray receiving paths is a 3-dimensional region formed when the infrared ray beam incident on the detection unit 24 of the infrared ray detection element 2 through the lens 31 is extended in a direction opposite to the traveling direction of the infrared ray. In other words, the infrared light receiving path is defined as an infrared light passing region through which an infrared beam used for imaging on the light receiving surface 24a of the detecting unit 24 of the infrared detection element 2 can pass. Further, the infrared ray receiving path is an effective region capable of detecting infrared rays emitted from a human body. The plurality of infrared light receiving paths are paths defined optically and not paths that are actually visible to the human eye. The infrared ray receiving path has a larger cross-sectional area through which the infrared ray beam can pass as it is farther from the detection unit 24. Each of the plurality of infrared light receiving paths may be regarded as having a one-to-one correspondence polarity with the detection section 24. The plurality of infrared light receiving paths in the detection region can be determined substantially by the infrared light detection element 2 and the multi-lens element 30 as described above, but also relates to the size and shape of the window member 63, the opening shape of the window hole 601, and the like.

The infrared detection device 100 is assumed to be disposed such that a normal direction to the center 200 of the light receiving surface 20 of the infrared detection element 2 is a horizontal direction in a state in which it is used.

In fig. 1, an optical axis OA1 of a lens 31 located at the center among 15 lenses 31 aligned in a row on the upper side among the multi-lens elements 30 is schematically shown. In the infrared detection device 100, the infrared ray passing through the lens 31 along the optical axis OA1 is directly incident on the infrared detection element 2. The term "directly incident" is defined as not being reflected by the reflecting member but being incident on the infrared detection element 2 after passing through the multi-lens element 30, and includes, for example, a case where the light passes through a window member 63 located between the multi-lens element 30 and the infrared detection element 2 and then is incident thereon. In fig. 1, the optical axis OA2 of the lens 31 located at the center among the 13 lenses 31 aligned in a row on the lower side of the multi-lens element 30 is schematically shown.

In the infrared detection device 100 of the present embodiment, a part of the infrared rays from below the infrared detection device 100, which pass through the multi-lens element 30 and do not directly enter the infrared detection element 2, is reflected by the 1 st mirror portion 4 and reflected by the 2 nd mirror portion 5 to enter the infrared detection element 2. More specifically, in the infrared detection device 100, infrared rays incident on the 1 st mirror portion 4 through at least the central lens 31 among the 15 lenses 31 arranged in a row on the upper side among the multi-lens elements 30 are incident on the infrared detection element 2 through reflection by the 1 st mirror portion 4 and further reflection by the 2 nd mirror portion 5. Here, in the infrared detection device 100, the 1 st mirror portion 4 is disposed above the infrared detection element 2, and the 2 nd mirror portion 5 is disposed below the infrared detection element 2, and therefore, the 1 st mirror portion 4 and the 2 nd mirror portion 5 do not overlap the plurality of infrared light receiving paths. Therefore, the infrared detection device 100 can expand the detection region downward while suppressing a decrease in sensitivity, as compared with the case where the 1 st mirror portion 4 and the 2 nd mirror portion 5 are not included.

In a preferred embodiment, the 1 st mirror 4 of the infrared detection device 100 includes a plurality (e.g., 2) of 1 st mirror surfaces 40 arranged along the arrangement direction of the infrared detection elements 2 and the multi-lens elements 30. In addition, in a preferred embodiment, the 2 nd mirror part 5 in the infrared detection device 100 includes a plurality of (for example, 2) 2 nd mirror surfaces 50 arranged along the arrangement direction of the infrared detection elements 2 and the multi-lens elements 30. In the combination of the plurality of 1 st mirror surfaces 40 and the plurality of 2 nd mirror surfaces 50 in the infrared detection device 100, it is preferable that a plurality of pairs (for example, 2 pairs) of the 1 st mirror surfaces 40 and the 2 nd mirror surfaces 50 arranged in the vertical direction are combined. Hereinafter, among the 21 st mirror surfaces 40 arranged along the arrangement direction of the infrared detection element 2 and the multi-lens element 30, there is a case where the 1 st mirror surface 40 close to the multi-lens element 30 is referred to as a1 st mirror surface 41, and the 1 st mirror surface 40 distant from the multi-lens element 30 is referred to as a1 st mirror surface 42. Among the 2 nd mirror surfaces 50 arranged along the arrangement direction of the infrared detection element 2 and the multi-lens element 30, the 2 nd mirror surface 50 closer to the multi-lens element 30 may be referred to as a2 nd mirror surface 51, and the 2 nd mirror surface 50 farther from the multi-lens element 30 may be referred to as a2 nd mirror surface 52. The infrared detection device 100 includes a combination pair of the 1 st mirror surface 41 and the 2 nd mirror surface 51, and a combination pair of the 1 st mirror surface 42 and the 2 nd mirror surface 52. In the infrared detection device 100, the optical axes (for example, an optical axis OA3 indicated by a one-dot chain line and an optical axis OA4 indicated by a two-dot chain line in fig. 1) defined to be different for each combined pair of the 1 st mirror surface 40 and the 2 nd mirror surface 50. Thus, in the infrared detection device 100, infrared rays can be incident on the infrared detection element 2 along the optical axes OA3 and OA4, respectively. Therefore, the infrared detection device 100 can detect a person sitting right under near.

The optical axis OA3 is defined by the lens 31, the 1 st mirror surface 41 and the 2 nd mirror surface 51 at the center position of the upper row of the multi-lens element 30. The optical axis OA4 is defined by the lens 31, the 1 st mirror surface 42 and the 2 nd mirror surface 52 at the center position of the upper row of the multi-lens element 30.

An angle formed by the optical axis OA3 and a normal line positioned at the center 200 of the light receiving surface 20 of the infrared detection element 2 and an angle formed by the optical axis OA4 and a normal line positioned at the center 200 of the light receiving surface 20 of the infrared detection element 2 are different from each other on the 1 st surface 301 side of the multi-lens element 30.

The angle formed by the optical axis OA1 and the normal is, for example, 6 °. The angle formed by the optical axis OA2 and the normal is, for example, 21 °. The angle formed by the optical axis OA3 and the normal is, for example, 60 °. The angle formed by optical axis OA4 and the normal is, for example, 45 °.

In the infrared detection device 100, a plurality of 1 st mirror surfaces 40 (1 st mirror surfaces 41 and 42) and a plurality of 2 nd mirror surfaces 50 (2 nd mirror surfaces 51 and 52) may be provided so that optical axes OA3 and OA4 defined for each combination of the 1 st mirror surface 40 and the 2 nd mirror surface 50 can be kept substantially parallel to the 1 st surface 301 side of the multi-lens element 30. Accordingly, in the infrared detection device 100, the amount of infrared rays that are reflected by the 1 st mirror portion 4, reflected by the 2 nd mirror portion 5, and then incident on the infrared detection element 2 can be increased (the amount of received infrared rays at the detection portion 24 is increased), and sensitivity can be improved. The definition of "substantially parallel" is preferably completely parallel, but is not limited thereto, and the angle between each other may be about 2 to 3 °.

The size of the 1 st mirror 4 and the 2 nd mirror 5 is preferably set so that the 3 d region formed when the infrared beam reflected by the 1 st mirror 4 and the 2 nd mirror 5 and incident on the infrared detection element 2 is extended in the direction opposite to the traveling direction of the infrared ray can only allow the passage through the lens 31 located at the center among the plurality (15) of lenses 31 aligned in a row on the upper side in the multi-lens element 30. This can suppress the occurrence of excessive stray light in the infrared detection device 100, and can suppress a decrease in sensitivity. The "stray light" refers to infrared rays generated by reflection of the 1 st mirror portion 4 and the 2 nd mirror portion 5 and unwanted in image formation.

The 1 st mirror surface 40 is preferably a concave curved surface. The 2 nd reflecting mirror surface 50 is preferably a concave curved surface. The concave curved surface is preferably aspherical. Accordingly, in the infrared detection device 100, the aberration of the image formed on the infrared detection element 2 can be reduced via the reflection optical system including the multi-lens element 30, the 1 st mirror portion 4, and the 2 nd mirror portion 5, and the sensitivity can be improved.

The infrared detection device 100 preferably further includes a3 rd mirror portion 8. The 3 rd mirror portion 8 is disposed above the infrared detection element 2 between the infrared detection element 2 and the multi-lens element 30. The 3 rd mirror portion 8 reflects a part of the infrared ray from the side of the infrared ray detection element 2, which has passed through the multi-lens element 30 and has not directly entered the infrared ray detection element 2, toward the infrared ray detection element 2. Accordingly, in the infrared detection device 100, the path of the infrared ray directly entering the infrared detection element 2 through the multi-lens element 30 is not blocked, and thus the horizontal viewing angle of the detection area can be enlarged. Therefore, in the infrared detection device 100, the detection region can be enlarged while suppressing a decrease in sensitivity.

The 3 rd mirror portion 8 is formed on a pentagonal tab 14 projecting downward from the lower surface of the upper tab 12. In the infrared detection device 100, the 3 rd mirror portion 8 is formed on 2 surfaces adjacent to each other on the lower side of the hanging-down piece 14, and the point is that the optical member 10 includes 23 rd mirror portions 8. In the infrared detection device 100, since the optical member 10 includes the 3 rd mirror portion 8, the relative positional accuracy of the 3 rd mirror portion 8 and the infrared detection element 2 can be improved. Here, the 3 rd mirror portion 8 is disposed above the infrared detection element 2. More specifically, the 3 rd mirror portion 8 is disposed obliquely above the light receiving surface 20 of the infrared detection element 2 between the infrared detection element 2 and the multi-lens element 30. The 3 rd mirror portion 8 is inclined toward the light receiving surface 20 of the infrared detection element 2. Accordingly, in the infrared detection device 100, as shown in fig. 11A and 11B, the infrared rays incident on the 3 rd mirror portion 8 through the multi-lens element 30 are more likely to be incident on the light receiving surface 20 of the infrared detection element 2, and the occurrence of stray light can be suppressed. The 3 rd mirror part 8 is a flat surface, but it is not limited thereto and may be a curved surface. In fig. 11A and 11B, the optical axes defined by the lens 31 positioned at the end portion of the upper 15 lenses 31 and the 3 rd mirror portion 8 are indicated by the alternate long and short dash line with respect to each 3 rd mirror portion 8.

The infrared detection device 100 preferably further includes a4 th mirror 9 (see fig. 2, 3A, and 4). The 4 th mirror 9 is disposed above the infrared detection element 2 between the infrared detection element 2 and the multi-lens element 30. The 4 th mirror 9 reflects the infrared ray passing through the multi-lens element 30 toward the infrared ray detection element 2. With this, the infrared detection apparatus 100 can increase the optical axis for making infrared rays incident on the infrared detection element 2 while suppressing the decrease in sensitivity. In the infrared detection device 100, a part of the infrared rays from below the infrared detection device 100, which pass through the multi-lens element 30 and do not directly enter the infrared detection element 2, enters the infrared detection element 2 by being reflected by the 4 th mirror 9.

The 4 th mirror part 9 is formed on both sides of the 1 st mirror part 4 in the left-right direction under the upper protruding piece 12. In this way, the 4 th mirror 9 is disposed obliquely above the infrared detection element 2 between the infrared detection element 2 and the multi-lens element 30 so as not to interfere with the 1 st mirror 4. The optical member 10 includes 24 th mirror portions 9. In the infrared detection device 100, since the optical member 10 includes the 4 th mirror portion 9, the relative positional accuracy of the 4 th mirror portion 9 and the infrared detection element 2 can be improved.

The 4 th mirror part 9 is not limited to the 1 st 4 th mirror surface, and may include, for example, 24 th mirror surfaces arranged along the arrangement direction of the infrared detection element 2 and the multi-lens element 30. In this case, in the infrared detection device 100, the optical axis on which infrared rays from the outside can enter the infrared detection element 2 is defined by the combination of each of the 2 th reflecting mirror surfaces and the multi-lens element 30. Thereby, the infrared detection apparatus 100 can increase the optical axis for incidence of the infrared rays to the infrared detection element 2 while suppressing the decrease in sensitivity. In the infrared detection device 100, a predetermined number (for example, 4) of optical axes are defined by a predetermined number (for example, 4) of lenses 31 among a plurality (for example, 15) of lenses 31 arranged in a line on the upper side in the 1 st 4-th reflecting mirror surface and the multi-lens element 30. Each of the 24 th reflecting mirror surfaces is preferably a concave curved surface. The 4 th mirror part 9 may include 1 or more 4 th mirror surfaces in addition to the 24 th mirror surfaces along the arrangement direction of the infrared detection elements 2 and the multi-lens elements 30.

In the infrared detection device 100, an angle formed by the optical axis (for example, OA3 and OA4) defined by the 1 st mirror unit 4 and the lens 31 and the horizontal plane may be larger than an angle formed by the optical axis defined by the 4 th mirror unit 9 and the lens 31 and the horizontal plane.

In the infrared detection device 100, the 24 th mirror surfaces may be designed such that the optical axis defined by one 4 th mirror surface of the 24 th mirror surfaces and the lens 31 positioned on the upper side of the multi-lens element 30 can be substantially parallel to the optical axis defined by the other 4 th mirror surface and the lens 31 positioned on the lower side of the multi-lens element 30. With this, in the infrared detection device 100, the amount of infrared rays reflected by the 4 th mirror 9 and incident on the infrared detection element 2 can be increased (the amount of received infrared rays at the detection unit 24 can be increased), and sensitivity can be improved. The meaning of "substantially parallel" is preferably completely parallel, but is not limited thereto, and the angle between each other may be about 2 to 3 °.

The above-described embodiment is only one of various embodiments of the present invention. The above-described embodiments may be variously modified according to design, etc. as long as the object of the present invention is achieved.

For example, each of the plurality of lenses 31 may be formed of a fresnel lens.

For example, in the infrared detection element 2, it is not limited to the pyroelectric element that outputs a current signal as an output signal in the current detection mode, and a pyroelectric element that outputs a voltage signal as an output signal in the voltage detection mode may be used. In this case, the current-voltage conversion circuit is not required in the amplification circuit 71 of the signal processing circuit 7 shown in fig. 10.

The signal processing circuit 7 may further include a determination circuit instead of the comparator circuit 73 and the output circuit 74, and the determination circuit may determine whether or not the number of times the voltage level of the analog voltage signal exceeds the predetermined value within a predetermined time is equal to or more than a predetermined number of times, and may output the human body detection signal when the number of times is determined to be equal to or more than the predetermined number of times.

The infrared detection element 2 is not limited to a four-line array type pyroelectric element, and may be a two-line array type pyroelectric element, for example. The infrared detection element 2 is not limited to a pyroelectric element, and may be a thermopile, a light emitting diode, or the like.

Examples of applications of the infrared detection device 100 are not limited to wiring tools, and can be applied to various devices. Examples of suitable devices include televisions, electronic signs, lighting equipment, air cleaners, air conditioners, copiers, facsimile machines, and antitheft devices. The device is not limited to a device disposed indoors, and may be a device disposed outdoors.

[ description of symbols ]

2 infrared ray detecting element

41 st mirror part

5 the 2 nd mirror part

8 3 rd mirror part

9 th mirror part

30 multi-lens element

31 lens

40 1 st mirror surface

41 st reflecting mirror surface

42 st reflecting mirror surface

50 nd 2 nd mirror surface

51 nd 2 nd mirror surface

52 nd 2 nd reflecting mirror surface

100 infrared detection device

Claims

1. An infrared detection device, comprising:

an infrared detection element; and

a multi-lens element having a plurality of lenses for condensing infrared rays to the infrared detection element, respectively, and further comprising:

a1 st mirror section disposed above the infrared detection element between the infrared detection element and the multi-lens element, for reflecting a part of the infrared rays that pass through the multi-lens element and are not directly incident on the infrared detection element; and

and a2 nd mirror portion disposed below the infrared detection element between the infrared detection element and the multi-lens element, for reflecting the infrared rays reflected by the 1 st mirror portion toward the infrared detection element.

2. The infrared detection device as set forth in claim 1,

the 1 st mirror part comprises a plurality of 1 st mirror surfaces arranged along the arrangement direction of the infrared detection element and the multi-lens element;

the 2 nd mirror part includes a plurality of 2 nd mirror surfaces arranged along the arrangement direction of the infrared detection element and the multi-lens element;

the combination of the 1 st mirror surface and the 2 nd mirror surface includes a plurality of pairs of the 1 st mirror surface and the 2 nd mirror surface arranged in the up-down direction.

3. The infrared detection device according to claim 1 or 2, further comprising a3 rd mirror portion;

the 3 rd reflecting mirror portion is disposed above the infrared detection element between the infrared detection element and the multi-lens element, and reflects a part of the infrared rays that pass through the multi-lens element from the side of the infrared detection element and do not directly enter the infrared detection element toward the infrared detection element.

4. The infrared detection device according to claim 1 or 2, further comprising a4 th mirror portion;

the 4 th mirror portion is disposed above the infrared detection element between the infrared detection element and the multi-lens element, and reflects the infrared rays incident through the multi-lens element toward the infrared detection element.

5. The infrared detection device as set forth in claim 1 or 2, wherein the multi-lens element is C-shaped when viewed from above and covers the infrared detection element.