Infrared detector

Abstract

This infrared lens unit comprises: a lens-barrel; and an infrared lens supported on the lens-barrel. The lens-barrel has: a barrel part which extends along the center axis extending vertically, has an inner circumferential surface surrounding the center axis, and has formed therein a through-hole configured from the inner circumferential surface; and a projecting part provided to the inner circumferential surface of the barrel part. The infrared lens is supported on the barrel part via the projecting part. The infrared lens is made of chalcogenide glass. The projecting part has, on a cross-section along a plane including the center axis, a straight portion which extends upwardly from the lower end to the upper end, and a slope portion which has a lower end positioned at the upper end of the straight portion. The slope portion extends from the lower end to the upper end so as to separate from the center axis, and inclines with respect to the straight portion. The infrared lens abuts against the straight portion and the slope portion of the projecting part. In this lens unit, the infrared lens using the chalcogenide glass can be formed by press molding.

Description

[Technical Field]

[0001] The present disclosure relates to an infrared lens unit including a lens barrel and an infrared lens supported inside the lens barrel, and an infrared detection device. [Background technology]

[0002] Generally, lens units in which the lens barrel and glass lens are integrated are structured so that the glass lens is supported by pressure from the lens barrel. In the lens unit, a sensor chip such as a light receiving element is mounted inside the lens barrel, and optical processing and airtight sealing are performed on the sensor chip.

[0003] Furthermore, the pressure stress from the lens barrel that supports the glass lens is a stress that occurs due to the difference in the linear thermal expansion coefficient between the lens barrel and the glass lens when the glass material is press-molded inside the lens barrel.

[0004] The infrared lens unit includes an infrared lens that is compatible with infrared rays, and the glass of the infrared lens is made of chalcogenide glass that transmits infrared rays.

[0005] Patent Document 1 discloses a conventional lens unit. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-156905 Summary of the Invention

[0007] The infrared lens unit includes a lens barrel and an infrared lens supported by the lens barrel. The lens barrel has a cylindrical portion extending along a central axis extending in the vertical direction, an inner peripheral surface surrounding the central axis, and a through hole formed by the inner peripheral surface, and a convex portion provided on the inner peripheral surface of the cylindrical portion. The infrared lens is supported by the cylindrical portion via the convex portion. The infrared lens is made of chalcogenide glass. In a cross section taken along a plane including the central axis, the convex portion has a linear portion extending from the lower end to the upper end in an upward direction, and an inclined portion having a lower end located at the upper end of the linear portion. The inclined portion extends from the lower end to the upper end so as to move away from the central axis and is inclined relative to the linear portion. The infrared lens abuts against the linear portion and the inclined portion of the convex portion.

[0008] In this lens unit, an infrared lens using chalcogenide glass can be formed by press molding. [Brief explanation of the drawings]

[0009] [Figure 1A] FIG. 1A is a schematic cross-sectional view of an infrared detection device according to an embodiment of the present disclosure. [Figure 1B] FIG. 1B is a schematic top view of the infrared detection device according to the embodiment. [Figure 2A] FIG. 2A is a schematic diagram of a press molding device illustrating a molding method for an infrared lens unit according to an embodiment. [Figure 2B] FIG. 2B is a schematic diagram of a press molding device illustrating a molding method for an infrared lens unit according to the embodiment. [Figure 2C] FIG. 2C is a schematic diagram of a press molding device illustrating a molding method for an infrared lens unit according to the embodiment. [Figure 3] FIG. 3 is an enlarged cross-sectional view of the infrared lens unit according to the embodiment. [Figure 4] FIG. 4 is an enlarged cross-sectional view of another infrared lens unit according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Below, infrared lens units according to embodiments of the present disclosure will be described with reference to the drawings. Note that each of the embodiments described below illustrates a preferred specific example of the present disclosure. Therefore, the shapes, arrangements and connection forms of components shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Therefore, among the components in the following embodiments, components that are not recited in the independent claims that represent the superordinate concept of the present disclosure will be described as optional components.

[0011] In addition, each drawing is a schematic diagram and is not necessarily an exact illustration. In each drawing, substantially the same structures are given the same reference numerals, and redundant explanations are omitted or simplified.

[0012] 1A and 1B are a cross-sectional view and a top view, respectively, schematically illustrating an infrared detection device 100 according to an embodiment of the present disclosure. FIG. 1A shows a cross section of the infrared detection device 100 taken along line IA-IA in FIG. 1B. The infrared detection device 100 includes an infrared lens unit 10 and an infrared sensor 20. The infrared lens unit 10 includes a lens barrel 11 and an infrared lens 12. Infrared rays 30 incident on the infrared lens 12 are focused on the light-receiving surface 20A of the infrared sensor 20. For example, infrared rays 31 incident on the center of the infrared lens 12 are focused on the center of the light-receiving surface 20A. Infrared rays 32 incident on the peripheral portion of the infrared lens 12, i.e., the right side in the figure, are focused on the left side of the light-receiving surface 20A. Infrared rays 33 incident on the peripheral portion of the infrared lens 12, i.e., the left side in the figure, are focused on the right side of the light-receiving surface 20A. The dashed line in the figure indicates the central axis 11B of the through-hole 11A in the lens barrel 11. The central axis 11B substantially coincides with a normal line passing through the center of the light receiving surface 20A. In this embodiment, the vertical direction along the central axis 11B in Fig. 1A is defined as an extension direction D. The infrared detecting device 100 detects, for example, the state of a person or the temperature distribution in a room.

[0013] The infrared sensor 20 includes a semiconductor chip 21 for detecting infrared rays and a base 22. A light receiving surface 20A is disposed on an upper surface 21A of the semiconductor chip 21. The semiconductor chip 21 is mounted on an upper surface 22A of the base 22.

[0014] The infrared lens unit 10 is mounted on an upper surface 22A of the base 22. The semiconductor chip 21 is disposed in a space 40 which is a closed space surrounded by the base 22 and the infrared lens unit 10.

[0015] The infrared lens unit 10 has a cylindrical lens barrel 11 made of metal and an infrared lens 12 with a light-collecting function. The glass constituting the infrared lens 12 is chalcogenide glass. The infrared lens 12 collects infrared rays 30 incident on the infrared lens 12 from outside the infrared detection device 100 onto the light-receiving surface 20A of the semiconductor chip 21. The infrared lens 12 is supported inside the lens barrel 11. As shown in FIG. 1A , a space 40 is defined by the infrared lens unit 10 and the base 22. The semiconductor chip 21 is disposed inside the space 40. The closed space 40 is filled with an inert gas such as nitrogen gas to suppress oxidation of the semiconductor chip 21.

[0016] The lens barrel 11 includes a tube portion 111 having an inner circumferential surface 111A and having a through-hole 11A formed therein, a protrusion 112 provided on the inner circumferential surface 111A of the tube portion 111 and arranged along a circumferential direction 111D (see FIG. 1B) centered on a central axis 11B of the inner circumferential surface 111A, and a flange portion 113 arranged at a lower end 2111, which is one of both ends (upper end 1111 and lower end 2111) of the tube portion 111 in the extension direction D. The inner circumferential surface 111A is a cylindrical surface centered on the central axis 11B. The inner circumferential surface 111A surrounds the central axis 11B and faces the central axis 11B. The protrusion 112 is a ring-shaped protrusion arranged along the inner circumferential surface 111A of the tube portion 111. Details of the protrusion 112 will be described later. A lower surface 113A of the flange portion 113 is connected to an upper surface 22A of the base 22. A projection for welding may be disposed on the lower surface 113A of the flange portion 113.

[0017] Next, a description will be given of a manufacturing method of the infrared lens unit 10. Figures 2A, 2B, and 2C are schematic diagrams of a press-molding apparatus 50 illustrating the manufacturing method of the infrared lens unit 10. The infrared lens 12 of the infrared lens unit 10 is press-molded using the press-molding apparatus 50.

[0018] The press molding apparatus 50 has a fixed mold 51, a sliding mold 52, and a trunk mold 53. The fixed mold 51 is a cylindrical mold having a large diameter portion 51A, a medium diameter portion 51B, and a small diameter portion 51C, each having different diameters. The diameters of the large diameter portion 51A, the medium diameter portion 51B, and the small diameter portion 51C decrease in this order. An upper surface 151C of the small diameter portion 51C is configured as a molding surface that transfers one lens surface of the infrared lens 12 (for example, the lower surface 12B of the infrared lens 12 in Figures 2A to 2C). The sliding mold 52 is a cylindrical mold having a large diameter portion 52A, a medium diameter portion 52B, and a small diameter portion 52C, each having different diameters. The diameters of the large diameter portion 52A, the medium diameter portion 52B, and the small diameter portion 52C decrease in this order. A molding surface for transferring the other lens surface of the infrared lens 12 (for example, the upper surface 12A of the infrared lens 12 in FIGS. 2A to 2C) is disposed on the lower surface 252C of the small diameter portion 52C. The body mold 53 is a cylindrical mold having a thick portion 53A and a thin portion 53B with different thicknesses. The thick portion 53A is thicker than the thin portion 53B. The lower end 253A of the thick portion 53A is connected to the upper end 153B of the thin portion 53B. The fixed mold 51 is inserted into an opening on one end side of the body mold 53. The fixed mold 51 is fixed to the body mold 53. The lower surface 253B of the thin portion 53B is in contact with the upper surface 151A of the large diameter portion 51A. The inner peripheral surface 253C of the thin portion 53B is in contact with the outer peripheral surface 451B of the medium diameter portion 51B. The sliding die 52 is inserted into the opening on the other end side of the barrel die 53. The sliding die 52 is slidable relative to the barrel die 53. The barrel die 53 functions as a sliding guide that limits the sliding direction of the sliding die 52 by bringing the inner peripheral surface 353A of the thick-walled portion 53A into contact with the outer peripheral surface 452B of the middle diameter portion 52B. Note that a temperature control unit 54 that controls the mold temperature during press molding is disposed on the fixed die 51 and the sliding die 52. The temperature control unit 54 can be configured, for example, by a known heater block.

[0019] A method for manufacturing the infrared lens unit 10 will now be described. First, the lens barrel 11 and the glass material 15 are prepared. The lens barrel 11 can be machined into a shape having a cylindrical portion 111, a convex portion 112, and a flange portion 113, for example, by cutting a metal member. The glass material 15 can be a block glass material formed by molding chalcogenide glass into a prismatic shape, or a ball glass material formed into a spherical shape. Next, the prepared lens barrel 11 and glass material 15 are placed in a molding space formed by a fixed mold 51, a sliding mold 52, and a barrel mold 53. Next, the temperature of the glass material 15 placed inside the press molding device 50 is raised to a temperature above its softening point. After the glass material 15 reaches a temperature suitable for press molding, the sliding mold 52 is slid to press the glass material 15. The glass material 15 is deformed by pressing to reach the tip of the convex portion 112, becoming a press-molded body 15A. Thereafter, press-molded body 15A is cooled until the temperature of press-molded body 15A drops to a temperature at which press-molded body 15A can be removed. After cooling, sliding mold 52 is removed from barrel mold 53, and infrared lens unit 10, in which lens barrel 11 and infrared lens 12 are integrated, is removed from the molding space.

[0020] During the cooling stage described above, infrared lens 12 is supported by convex portion 112 of barrel 11 due to stress resulting from the difference in the linear thermal expansion coefficients of barrel 11 and glass material 15. Specifically, infrared lens 12 is supported by barrel 11 so as to be supported by cylindrical portion 111 via convex portion 112. This stress results from the fact that the linear thermal expansion coefficient of glass material 15 is smaller than the linear thermal expansion coefficient of barrel 11. Specifically, because the amount of contraction of glass material 15 during cooling is smaller than the amount of contraction of barrel 11, a pressure-welding stress is applied from barrel 11 to press-molded body 15A after cooling.

[0021] Next, the convex portion 112 disposed on the lens barrel 11 will be described. FIG. 3 is an enlarged cross-sectional view of the periphery of the convex portion 112 in the infrared lens unit 10. FIG. 3 shows a cross-section along the extension direction D, specifically, a cross-section of the convex portion 112 along a plane 100S including the central axis 11B shown in FIG. 1B. In the cross-section, the convex portion 112 protrudes from the inner circumferential surface 111A of the lens barrel 11 toward the central axis 11B. In the cross-section, the convex portion 112 includes an upper portion 112A, a lower portion 112B, a linear portion 112C, and an inclined portion 112D. The lower portion 112B faces the infrared sensor 20 and is perpendicular to the extension direction D. The upper portion 112A faces the opposite side to the lower portion 112B and is perpendicular to the extension direction D. The linear portion 112C is the inner circumferential surface of the convex portion 112 and is aligned with the extension direction D. The inclined portion 112D is inclined with respect to the extension direction D, i.e., the linear portion 112C. Lower end 2112D, which is the inner circumferential end of inclined portion 112D, is continuous with upper end 1112C of straight portion 112C, and upper end 1112D, which is the outer circumferential end of inclined portion 112D, is continuous with inner circumferential end 1112A of upper portion 112A. Note that the portions where convex portion 112 and infrared lens 12 abut are straight portion 112C and inclined portion 112D. In other words, upper portion 112A and lower portion 112B of convex portion 112 do not abut with infrared lens 12.

[0022] Specifically, straight portion 112C has upper end 1112C and lower end 2112C, and extends linearly upward from lower end 2112C to upper end 1112C. Inclined portion 112D has upper end 1112D and lower end 2112D located at upper end 1112C of straight portion 112C, and extends linearly from lower end 2112D to upper end 1112D away from central axis 11B and is inclined with respect to straight portion 112C. Upper portion 112A has inner circumferential end 1112A located at upper end 1112D of inclined portion 112D, and outer circumferential end 2112A located on inner circumferential surface 111A. The upper portion 112A extends linearly from the inner peripheral end 1112A to the outer peripheral end 2112A so as to move away from the central axis 11B, and in this embodiment, extends from the inner peripheral end 1112A to the outer peripheral end 2112A in a direction perpendicular to the central axis 11B. The lower portion 112B has an inner peripheral end 1112B located at the lower end 2112C of the linear portion 112C, and an outer peripheral end 2112B located on the inner circumferential surface 111A. The lower portion 112B extends linearly from the inner peripheral end 1112B to the outer peripheral end 2112B so as to move away from the central axis 11B, and in this embodiment, extends from the inner peripheral end 1112B to the outer peripheral end 2112B in a direction perpendicular to the central axis 11B. Upper portion 112A and lower portion 112B do not have to extend in a direction perpendicular to central axis 11B from inner peripheral ends 1112A, 1112B to outer peripheral ends 2112A, 2112B, respectively, and do not have to extend linearly. Infrared lens 12 abuts against upper end 1112C of straight portion 112C and lower end 2112D of inclined portion 112D of convex portion 112. In the embodiment, infrared lens 12 does not abut against lower end 2112C of straight portion 112C of convex portion 112 or upper end 1112D of inclined portion 112D, but may abut against at least one of lower end 2112C and upper end 1112D.

[0023] 3, if the angle D11 formed between the direction D11 from the lower end 2112C of the straight portion 112C toward the upper end 1112C and the direction D21 from the lower end 2112D toward the upper end 1112D of the inclined portion 112D is θ1, the width of the contact surface of the inclined portion 112D that contacts the infrared lens 12 is L1, and the width along the extension direction D from the lower end 2112D of the inclined portion 112D to the upper surface of the infrared lens 12 is L2, then width L1 is expressed as L1 = L2 / cos θ1. In other words, by providing the inclined portion 112D on the contact surface that contacts the infrared lens 12, the contact area can be increased compared to a lens unit whose contact surface is composed only of the straight portion 112C. Furthermore, by increasing the contact area, the pressure stress per unit area applied from the lens barrel 11 can be reduced, thereby suppressing chipping due to press molding. As a result, the infrared lens 12 of the infrared lens unit 10 using chalcogenide glass can be formed by press molding.

[0024] Chalcogenide glass is more fragile than oxide glass, which is the glass material for glass lenses used in regular press molding. Tests on the scratch hardness of glass have shown that chalcogenide glass is more fragile than regular oxide glass, and one possible reason for this is thought to be that chalcogenide glass has a relatively low bond energy. Due to this fragility of chalcogenide glass, press molding of infrared lens units using chalcogenide glass has not yet been put to practical use.

[0025] In the infrared lens unit 10 according to the embodiment, as described above, the infrared lens 12 made of chalcogenide glass can be formed by press molding.

[0026] Increasing the angle θ1 between the inclined portion 112D and the extension direction D, i.e., the central axis 11B, can increase the contact area described above, but an increase in the contact area leads to a decrease in the pressure contact stress between the infrared lens 12 and the convex portion 112. In the infrared lens unit 10, a pressure test was carried out to confirm airtightness between the inside of the infrared lens 12 of the lens barrel 11, i.e., the side of the infrared sensor 20, and the outside of the infrared lens 12, i.e., the outside of the infrared detection device 100. As a result, it was confirmed that airtightness could be ensured if the angle θ1 was in the range of 20°≦θ1≦35°.

[0027] 3, if the compression stress per unit area in the straight portion 112C is F1 and the compression stress per unit area in the inclined portion 112D is F2, F2 can be expressed as F1·cosθ1. From this, the compression stress per unit area in the straight portion 112C is constant regardless of changes in θ1, but the compressive stress per unit area in the inclined portion 112D changes with changes in θ1. Therefore, in order to actively ensure airtightness due to the reduction in the compression stress in the inclined portion 112D, it is preferable to make the surface roughness of the inclined portion 112D greater than the surface roughness of the straight portion 112C.

[0028] As for types of chalcogenide glass, sulfur compound-based chalcogenide glass and selenium compound-based chalcogenide glass are suitable for the press molding described above. When sulfur compound-based chalcogenide glass is used for the infrared lens 12, the linear thermal expansion coefficient of sulfur compound-based chalcogenide glass is 14×10 -6 Therefore, the metal used for the lens barrel 11 has a linear thermal expansion coefficient of 17.3×10 -6 It is preferable to use stainless steel of this type. The sulfur compound-based chalcogenide glass can be, for example, IIR-SF2 manufactured by Isuzu Glass. This sulfur compound-based chalcogenide glass has a softening point of 276°C, a glass transition temperature of 245°C, and a molding temperature of 300°C. In this case, the pressing pressure is preferably 5 kgf to 50 kgf. The temperature at which the pressed compact can be removed (press release temperature) can be 240°C.

[0029] In addition, when a selenium compound-based chalcogenide glass is used for the infrared lens 12, the linear thermal expansion coefficient of the selenium compound-based chalcogenide glass is 16.2×10 -6 Therefore, the metal used for the lens barrel 11 has a linear thermal expansion coefficient of 23.8×10 -6 Aluminum or a linear thermal expansion coefficient of 19.6 x 10 -6 It is preferable to use brass of this type. As the selenium compound-based chalcogenide glass, for example, IRG203 manufactured by Xinhuaguang can be used. This selenium compound-based chalcogenide glass has a softening point of 301°C, a glass transition temperature of 266°C, and a molding temperature of 330°C. In this case, the pressing pressure is preferably 5 kgf to 50 kgf. Furthermore, the temperature at which the pressed compact can be removed (press release temperature) can be 260°C.

[0030] (Variation) Figure 4 is a cross-sectional view of infrared lens unit 101 in a modified example. In Figure 4, the same parts as those in infrared lens unit 10 shown in Figures 1A, 1B, and 3 are given the same reference numerals. Infrared lens unit 101 has a convex part 114 provided on inner circumferential surface 111A of cylindrical part 111 instead of convex part 112 of infrared lens unit 10. Figure 4 shows an enlarged view of the periphery of the convex part.

[0031] In a cross section taken along extension direction D, convex portion 114 has upper portion 112A, straight portion 112C, inclined portion 112D, and lower portion 112B of convex portion 112, and further has inclined portion 114E provided between lower portion 112B and straight portion 112C. That is, convex portion 114 in the modified example has inclined portion 114D continuing between upper portion 114A and straight portion 114C, and inclined portion 114E continuing between lower portion 114B and straight portion 114C. Note that the portions where convex portion 114 abuts infrared lens 12 are straight portion 114C, inclined portion 114D, and inclined portion 114E. In other words, upper portion 114A and lower portion 114B of convex portion 114 do not abut infrared lens 12. With this structure, infrared lens 12 sandwiches convex portion 112 from above and below, making it possible to prevent infrared lens 12 from falling off lens barrel 11. Upper portion 114A and lower portion 114B of convex portion 114 do not abut on infrared lens 12.

[0032] Specifically, straight portion 114C has an upper end 1114C and a lower end 2114C, and extends linearly upward from lower end 2114C to upper end 1114C. Inclined portion 114D has an upper end 1114D and a lower end 2114D located at upper end 1114C of straight portion 114C, extends linearly from lower end 2114D to upper end 1114D away from central axis 11B, and is inclined with respect to straight portion 114C. Inclined portion 114E has a lower end 2114E and an upper end 1114E located at lower end 2114C of straight portion 114C, extends linearly from upper end 1114D to lower end 2114D away from central axis 11B, and is inclined with respect to straight portion 114C. The upper portion 114A has an inner peripheral end 1114A located at the upper end 1114D of the inclined portion 114D and an outer peripheral end 2114A located at the inner peripheral surface 111A. The upper portion 114A extends linearly from the inner peripheral end 1114A to the outer peripheral end 2114A so as to move away from the central axis 11B. In this embodiment, the upper portion 114A extends in a direction perpendicular to the central axis 11B from the inner peripheral end 1114A to the outer peripheral end 2114A. The lower portion 114B has an inner peripheral end 1114B located at the lower end 2114E of the inclined portion 114E and an outer peripheral end 2114B located at the inner peripheral surface 111A. The lower portion 114B extends linearly from the inner peripheral end 1114B to the outer peripheral end 2114B so as to move away from the central axis 11B. In this embodiment, the lower portion 114B extends in a direction perpendicular to the central axis 11B from the inner peripheral end 1114B to the outer peripheral end 2114B. Upper portion 114A and lower portion 114B do not have to extend in a direction perpendicular to central axis 11B from inner peripheral ends 1114A, 1114B to outer peripheral ends 2114A, 2114B, respectively, and do not have to extend linearly. Infrared lens 14 abuts against upper end 1114C and lower end 2114C of linear portion 114C of convex portion 114, lower end 2114D of inclined portion 114D, and upper end 1114E of inclined portion 114E. In the embodiment, infrared lens 14 does not abut against lower end 2114E of inclined portion 114E of convex portion 114 or upper end 1114D of inclined portion 114D, but may abut against at least one of lower end 2114E and upper end 1114D.

[0033] Furthermore, the angle θ2 formed by the direction D12 from the upper end 1114C of the straight portion 114C toward the lower end 2114C and the direction D22 from the upper end 1114E toward the lower end 2114E of the inclined portion 114E is preferably equal to the angle θ1 formed by the direction D11 from the lower end 2114C of the straight portion 114C toward the upper end 1114C and the direction D21 from the lower end 2114D toward the upper end 1114D of the inclined portion 114D, and airtightness can be ensured if the angle θ1 is within the ranges of 20°≦θ1≦35° and 20°≦θ2≦35°. To actively ensure airtightness due to the reduced pressure-contact stress of the inclined portions 114D and 114E, it is preferable to make the surface roughness of the inclined portions 114D and 114E greater than the surface roughness of the straight portion 114C.

[0034] As for the other configurations, the same functions and effects as those of the infrared detection device described in the first embodiment can be obtained.

[0035] In the embodiments, terms indicating directions such as "up and down direction," "upper end," "lower end," "top," and "lower" indicate relative directions determined only by the relative positional relationships of components of the infrared lens unit such as the lens barrel and infrared lens, and do not indicate absolute directions such as the vertical direction. [Industrial Applicability]

[0036] The infrared lens unit according to the present disclosure can be realized by press molding, and is particularly useful in infrared detection devices used in monitoring systems for building air conditioning and the like, where low cost is required. [Explanation of symbols]

[0037] 10 Infrared lens unit 11 Telescope tube 11A through hole 11B Center axis 12 Infrared lens 22 Foundation 20 Infrared sensor 40 space 100 Infrared detector 112,114 Convex part 112C,114C Straight section 112D Inclined portion (first inclined portion) 114D Inclined section (first inclined section) 114E Inclined portion (second inclined portion) D Stretching direction

Claims

1. The base and an infrared sensor disposed on the base; an infrared lens unit disposed on the base; An infrared detection device comprising: The infrared lens unit is a cylindrical portion having an inner circumferential surface extending along a central axis extending in the vertical direction and surrounding the central axis, the cylindrical portion having a through hole formed by the inner circumferential surface; and a lens barrel having a ring-shaped protrusion provided on the inner peripheral surface of the cylindrical portion and extending in a circumferential direction around the central axis; an infrared lens supported by the lens barrel so as to be supported by the cylindrical portion via the convex portion; Equipped with the infrared lens is made of chalcogenide glass, The convex portion has, in a cross section taken along a plane including the central axis, a linear portion having an upper end and a lower end and extending upward from the lower end to the upper end; a first inclined portion having an upper end and a lower end located at the upper end of the linear portion, the first inclined portion extending from the lower end to the upper end so as to move away from the central axis and inclined with respect to the linear portion; It has the infrared lens is in contact with the linear portion and the first inclined portion of the convex portion, Furthermore, The infrared detection device, wherein the infrared sensor is disposed in a space surrounded by the base and the infrared lens unit.

2. 2. The infrared detection device according to claim 1, wherein an angle formed between a direction from the lower end to the upper end of the linear portion and a direction from the lower end to the upper end of the first inclined portion is equal to or greater than 20° and equal to or less than 35°.

3. 3. The infrared detection device according to claim 1, wherein the surface roughness of the first inclined portion is greater than the surface roughness of the linear portion.

4. the infrared lens is made of a sulfur compound-based chalcogenide glass, 4. The infrared detection device according to claim 1, wherein the lens barrel is made of stainless steel.

5. the infrared lens is made of selenium compound-based chalcogenide glass, 4. The infrared detection device according to claim 1, wherein the lens barrel is made of aluminum or brass.

6. 6. The infrared detection device according to claim 1, wherein the convex portion has, in the cross section, a lower end and an upper end located at the lower end of the straight portion, and further has a second inclined portion extending from the upper end to the lower end so as to move away from the central axis and inclined with respect to the straight portion.

7. 7. The infrared detection device according to claim 6, wherein an angle formed between a direction from the lower end to the upper end of the straight portion and a direction from the lower end to the upper end of the first inclined portion is equal to an angle formed between a direction from the upper end to the lower end of the straight portion and a direction from the upper end to the lower end of the second inclined portion.

8. 8. The infrared detection device according to claim 7, wherein the infrared lens is in contact with the linear portion, the first inclined portion, and the second inclined portion of the convex portion.

9. 2. The infrared detection device according to claim 1, wherein the space in which the infrared sensor is disposed is surrounded by the base, the infrared lens of the infrared lens unit, and the cylindrical portion of the lens barrel.

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