Infrared sensor

Abstract

The purpose of the present invention is to suppress electrical effects on the periphery in an infrared sensor. This infrared sensor (100) is provided with: a package body (31); an infrared sensor chip (1) which is mounted on the front surface (310) of the package body (31); a metal outside cap (32) which has the function of transmitting infrared rays to be detected by the infrared sensor chip (1) and which is attached to the package body (31) so as to cover the front of the infrared sensor chip (1); a metal inside cap (4) which has the function of transmitting infrared rays to be detected by the infrared sensor chip (1) and which is arranged between the package body (31) and the outside cap (32) so as to cover the front of the infrared sensor chip (1); and a ground terminal (40) which is connected to an external ground. The outside cap (32) is electrically insulated from the inside cap (4) and the infrared sensor chip (1). The inside cap (4) is electrically connected to the ground terminal (4).

Description

[Technical Field]

[0001] The present disclosure relates generally to infrared sensors, and more particularly to an infrared sensor that houses an infrared sensor chip within a package. [Background technology]

[0002] Patent Document 1 discloses an infrared sensor, which includes an infrared detection element, a package, and an infrared lens.

[0003] The package comprises a substrate and an outer cover. The infrared detection element is mounted on the substrate. The outer cover is connected to the substrate by welding at its periphery via a metal ring so that it can be connected to the ground potential of the motherboard on which the infrared sensor is mounted. The upper part of the outer cover has a cylindrical part that protrudes toward the outside of the package. The tip of the cylindrical part has a hole (window) that allows infrared light to pass through. The infrared lens is attached to the outer cover so as to close the base of the cylindrical part of the outer cover. The infrared lens focuses infrared light onto the infrared detection element. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-200559 Summary of the Invention

[0005] In an infrared sensor such as that described in Patent Document 1, when the ground potential of the motherboard on which the infrared sensor is mounted fluctuates, it may be desirable to suppress the electrical influence of the outer cover on the surroundings that accompanies this fluctuation in ground potential.

[0006] The present disclosure has been made in view of the above points, and aims to provide an infrared sensor that can suppress electrical influence on the surroundings.

[0007] Book An infrared sensor according to one aspect of the disclosure includes a package body, an infrared sensor chip, an outer cap, an inner cap, an electric circuit, and A ground wiring portion; The outer cap is conductive. The infrared sensor chip is mounted on the front surface of the package body. The outer cap is attached to the package body so as to cover the front of the infrared sensor chip. The outer cap has a function of transmitting infrared light to be detected by the infrared sensor chip. The inner cap is conductive. The inner cap is disposed between the package body and the outer cap so as to cover the front of the infrared sensor chip. The inner cap has a function of transmitting infrared light to be detected by the infrared sensor chip. The electrical circuit includes an IC chip that processes the detection signal of the infrared sensor chip, a connection terminal that outputs an output signal of the IC chip to the outside, and a conductor wiring portion that electrically connects the IC chip and the connection terminal. The package body has a ground terminal that is connected to an external ground. The ground wiring portion electrically connects the inner cap and the ground terminal. The outer cap is electrically insulated from the inner cap and the infrared sensor chip, the inner cap is electrically connected to the ground terminal, and the shortest distance between the outer cap and the inner cap is shorter than the shortest distance between the outer cap and the electrical circuit. The shortest distance between the outer cap and the ground wiring portion is smaller than the shortest distance between the outer cap and the electric circuit. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view schematically illustrating an infrared sensor according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a side view of the infrared sensor. [Figure 3] FIG. 3 is a partially see-through perspective view of the infrared sensor. [Figure 4] FIG. 4 is a perspective view of the infrared sensor with the outer cap removed. [Figure 5]FIG. 5 is a layout diagram of a plurality of pixel units in an infrared sensor chip included in the infrared sensor of the above embodiment. [Figure 6] FIG. 6 is a cross-sectional view of a pixel portion of the infrared sensor chip. [Figure 7] FIG. 7 is a partially cutaway plan view of a pixel portion of the infrared sensor chip. [Figure 8] FIG. 8 is a circuit block diagram of the infrared sensor of the same. [Figure 9] FIG. 9 is a plan view of the package body of the infrared sensor. [Figure 10] FIG. 10 is a diagram showing an outline of the main part of the infrared sensor. [Figure 11] FIG. 11 is a diagram for explaining Paschen's law. DETAILED DESCRIPTION OF THE INVENTION

[0009] An infrared sensor 100 according to an embodiment will be described below with reference to the accompanying drawings. The drawings described in the following embodiments are schematic diagrams, and the ratios of the sizes and thicknesses of the components in the drawings do not necessarily reflect the actual dimensional ratios.

[0010] (1) Overview As shown in FIG. 1, the infrared sensor 100 of this embodiment includes an infrared sensor chip 1, a package body 31, and an outer cap 32.

[0011] The infrared sensor chip 1 is mounted on one main surface of the package body 31. Hereinafter, the direction of the field of view of the infrared sensor chip 1 (upward in FIG. 1) will be referred to as "front," and the opposite direction (downward in FIG. 1) will be referred to as "rear." Therefore, the one main surface of the package body 31 on which the infrared sensor chip 1 is mounted corresponds to the front surface 310 of the package body 31. However, these directions are for the sake of convenience in explaining the positional relationship between the components, and do not limit the orientation of the infrared sensor 100 when in use.

[0012] The package body 31 includes a ground terminal 40. The ground terminal 40 is a terminal that is connected to an external ground (for example, the ground potential of a motherboard on which the infrared sensor 100 is mounted).

[0013] The outer cap 32 is attached to the package body 31 so as to cover the front of the infrared sensor chip 1. The outer cap 32 is conductive. The outer cap 32 is made of, for example, metal. The outer cap 32 has a function of transmitting infrared rays to be detected by the infrared sensor chip 1. Here, the outer cap 32 has an opening 320 in front of the infrared sensor chip 1, and transmits the infrared rays to be detected through this opening 320. In other words, "the outer cap 32 has a function of transmitting infrared rays to be detected by the infrared sensor chip 1" means that the outer cap 32 has the opening 320 in front of the infrared sensor chip 1.

[0014] The infrared sensor 100 further comprises an inner cap 4 .

[0015] The inner cap 4 is disposed between the package body 31 and the outer cap 32 so as to cover the front of the infrared sensor chip 1. The inner cap 4 is conductive. The inner cap 4 is made of, for example, metal. The inner cap 4 has the function of transmitting infrared rays to be detected by the infrared sensor chip 1. Here, the inner cap 4 has an opening 410 in front of the infrared sensor chip 1, and transmits the infrared rays to be detected through this opening 410. In other words, "the inner cap 4 has the function of transmitting infrared rays to be detected by the infrared sensor chip 1" means that the inner cap 4 has the opening 410 in front of the infrared sensor chip 1.

[0016] In the infrared sensor 100 of this embodiment, the outer cap 32 is not electrically connected to the inner cap 4 and the infrared sensor chip 1. In other words, the outer cap 32 is electrically insulated from the inner cap 4 and the infrared sensor chip 1. On the other hand, the inner cap 4 is electrically connected to the ground terminal 40. Here, as shown in FIG. 1 , the inner cap 4 is electrically connected to the ground terminal 40 of the package body 31 via a ground wiring portion 400, which is a part of the conductive portion of the package body 31.

[0017] In conventional infrared sensors such as those described in Patent Document 1, the outer cover is connected to a ground terminal. This ground terminal is connected to the ground potential of, for example, a motherboard on which the infrared sensor is mounted. Therefore, if the ground potential of the motherboard fluctuates, the outer cover may electrically affect the surrounding area. For example, if a foreign object comes into contact with the outer cover, the foreign object may be electrically affected by the outer cover. Therefore, in conventional infrared sensors, a protective cover is disposed in front of the outer cover to prevent the outer cover from electrically affecting the surrounding area.

[0018] In contrast, in the infrared sensor 100 of this embodiment, the inner cap 4 is electrically connected to the ground terminal 40. Furthermore, the outer cap 32 is electrically insulated from the ground and the infrared sensor chip 1, that is, is in a floating state. Therefore, even if the ground potential of the motherboard connected to the ground terminal 40 fluctuates, the potential of the outer cap 32 is unlikely to fluctuate. Therefore, the infrared sensor 100 of this embodiment has the advantage of being able to suppress (reduce) electrical influences on the surroundings.

[0019] Furthermore, conventional infrared sensors are provided with a protective cover. Therefore, in conventional infrared sensors, the infrared light to be detected is attenuated when passing through the protective cover, which may result in a decrease in the accuracy of infrared detection. In contrast, the infrared sensor 100 of the present embodiment does not require a protective cover, which has the advantage of enabling improved detection accuracy compared to conventional infrared sensors that are provided with a protective cover. Furthermore, because a protective cover is not required, this can also contribute to cost reduction compared to conventional infrared sensors that are provided with a protective cover.

[0020] (2) Details The infrared sensor 100 of this embodiment will be described in more detail below with reference to the drawings.

[0021] 1 to 4, the infrared sensor 100 includes an infrared sensor chip 1, an IC chip 51, a package 3, an inner cap 4, and a lens 6. The package 3 includes a package body 31 and an outer cap 32. The package body 31 includes a ground terminal 40 and a connection terminal 52. As shown in FIG. 1, the infrared sensor chip 1 and the IC chip 51 are mounted on a front surface 310 of the package body 31.

[0022] For ease of explanation, the front-to-rear direction (the direction along the field of view of the infrared sensor chip 1) will be referred to as the "first direction D1" below. The direction perpendicular to the first direction D1, in which the infrared sensor chip 1 and the IC chip 51 are aligned, will be referred to as the "second direction D2." The direction perpendicular to both the first direction D1 and the second direction D2 will be referred to as the "third direction D3."

[0023] 1 shows the infrared sensor chip 1 and the IC chip 51 as being flip-chip mounted on the package body 31 to make it easier to understand the connection relationship between the components. However, in this embodiment, as will be described below, the infrared sensor chip 1 and the IC chip 51 are electrically connected to the wiring portion of the package body 31 by wire bonding. Of course, in another aspect of the present disclosure, the infrared sensor chip 1 and / or the IC chip 51 may be flip-chip mounted on the package body 31.

[0024] (2.1) Infrared sensor chip As shown in FIG. 4, the infrared sensor chip 1 is mounted on the front surface 310 of the package body 31.

[0025] As shown in Fig. 5, the infrared sensor chip 1 includes a substrate 101 and a plurality of (e.g., 64) pixel units 102. The substrate 101 is a silicon substrate. The plurality of pixel units 102 are provided on a first main surface 111 (see Fig. 6) of the substrate 101. The outer periphery of the infrared sensor chip 1 in plan view from the thickness direction of the substrate 101 is, for example, rectangular. The outer periphery of the infrared sensor chip 1 may be rectangular, square, or the like.

[0026] The plurality of pixel units 102 are arranged in an array on the first main surface 111 side of the substrate 101. More specifically, the plurality of pixel units 102 (64 in the example of FIG. 5) are arranged in a two-dimensional array of m rows and n columns (m and n are natural numbers: m=8, n=8 in the example of FIG. 5).

[0027] The infrared sensor chip 1 includes a film structure 103 that constitutes a part of each of the plurality of pixel units 102. The film structure 103 is supported by the substrate 101 on the first main surface 111 side of the substrate 101.

[0028] 6 and 7, the film structure 103 includes a silicon oxide film 131, a silicon nitride film 132, an interlayer insulating film 133, and a passivation film 134. In the film structure 103, the silicon oxide film 131, the silicon nitride film 132, the interlayer insulating film 133, and the passivation film 134 are arranged in this order from the substrate 101 side. The silicon oxide film 131 is directly supported by the substrate 101. Note that FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 7.

[0029] The film structure 103 includes a plurality (64) of thermal infrared detecting units 104 that correspond one-to-one to the plurality (64) of pixel units 102. The plurality of thermal infrared detecting units 104 are arranged in a two-dimensional array of m rows and n columns (8 rows and 8 columns) on the first main surface 111 side of the substrate 101. Each of the plurality of thermal infrared detecting units 104 is included in a corresponding one of the plurality of pixel units 102.

[0030] Each of the plurality of thermal-type infrared detection units 104 in the film structure 103 includes a thermoelectric conversion unit 105 formed on a silicon nitride film 132. The thermoelectric conversion unit 105 includes a plurality of (e.g., six) thermopiles 106. In the thermoelectric conversion unit 105, the plurality of thermopiles 106 are connected in series.

[0031] The interlayer insulating film 133 covers the thermoelectric conversion unit 105 on the surface side of the silicon nitride film 132. The interlayer insulating film 133 is, for example, a boron phosphorus silicon glass (BPSG) film. The passivation film 134 is, for example, a laminated film of a phosphosilicate glass (PSG) film and a nondoped silicate glass (NSG) film formed on the PSG film. In the film structure 103, the portion of the laminated film of the interlayer insulating film 133 and the passivation film 134 that is formed in the thermal infrared detection unit 104 also serves as the infrared absorbing film 170.

[0032] The substrate 101 has, on its first main surface 111 side, a plurality of cavities 113 (see FIG. 6 ) that correspond one-to-one to the plurality of thermal-type infrared detection units 104. The opening shape of the cavities 113 on the first main surface 111 of the substrate 101 is rectangular. Each of the plurality of cavities 113 in the substrate 101 is formed directly below a part of a corresponding thermal-type infrared detection unit 104 among the plurality of thermal-type infrared detection units 104. As a result, a part of each of the plurality of thermal-type infrared detection units 104 is spaced apart from the substrate 101 in the thickness direction of the substrate 101. As shown in FIGS. 6 and 7 , a plurality of slits 144 that penetrate the substrate 101 in the thickness direction and connect to the cavities 113 are formed in parts of the thermal-type infrared detection units 104 that are located inside the opening edge of the cavities 113 in a plan view in the thickness direction of the substrate 101.

[0033] In each of the thermal infrared detection units 104, a plurality of slits 144 are formed, and the portion of the substrate 101 that overlaps with the cavity 113 in the thickness direction is divided into six regions. The six regions are arranged, for example, in a two-dimensional array of three rows and two columns. Each of the six regions includes one thermopile 106. Note that only two of the six regions are shown in FIG. 7.

[0034] Each thermopile 106 has a plurality of (here, nine) thermocouples 160. Each of the plurality of thermocouples 160 includes an n-type polysilicon wiring 161, a p-type polysilicon wiring 162, and a first connection portion 163 that electrically connects first ends of the n-type polysilicon wiring 161 and the p-type polysilicon wiring 162 to each other. As shown in FIG. 6 , the n-type polysilicon wiring 161 and the p-type polysilicon wiring 162 are formed on a silicon nitride film 132. The material of the first connection portion 163 is, for example, an Al—Si alloy. The thermopile 106 also includes a second connection portion 164 that electrically connects second ends of the n-type polysilicon wiring 161 and the p-type polysilicon wiring 162 of adjacent thermocouples 160 among the plurality of thermocouples 160 to each other. The material of the second connection portion 164 is, for example, an Al—Si alloy.

[0035] In the thermopile 106, the first end of the n-type polysilicon wiring 161, the first end of the p-type polysilicon wiring 162, and the first connecting portion 163 in each of the multiple thermocouples 160 form one hot junction T1. Therefore, the thermopile 106 includes multiple (nine) hot junctions T1. In addition, in the thermopile 106, the second end of the n-type polysilicon wiring 161, the second end of the p-type polysilicon wiring 162, and the second connecting portion 164 of two adjacent thermocouples 160 form one cold junction T2. ​​Therefore, the thermopile 106 includes multiple (eight) cold junctions T2.

[0036] Each hot junction T1 of the thermopile 106 is arranged so as to overlap a cavity 113 in the thickness direction of the substrate 101, and each cold junction T2 is arranged so as not to overlap a cavity 113 in the thickness direction of the substrate 101.

[0037] 6, each of the plurality of pixel units 102 includes a MOS transistor 107 in addition to a thermal infrared detection unit 104. The MOS transistor 107 of each of the plurality of pixel units 102 is a switching element for selecting the pixel unit. In other words, each of the plurality of MOS transistors 107 is a switching element for extracting an output voltage of the thermoelectric conversion unit 105 included in the corresponding pixel unit 102. The MOS transistor 107 has a well region 171, a drain region 173, a source region 174, a channel stopper region 172, a gate insulating film 175, a gate electrode 176, a drain electrode 177, a source electrode 178, and a ground electrode 179.

[0038] The well region 171, the drain region 173, the source region 174, and the channel stopper region 172 are formed in the substrate 101. The gate insulating film 175 is formed on the first main surface 111 of the substrate 101. The gate electrode 176 is formed on the gate insulating film 175. The drain electrode 177 is formed on the drain region 173. The source electrode 178 is formed on the source region 174. The ground electrode 179 is formed on the channel stopper region 172.

[0039] In each pixel unit 102, a first terminal of the thermoelectric conversion unit 105 is connected to a first wiring (readout line) via a MOS transistor 107. A gate electrode 176 of the MOS transistor 107 is connected to a second wiring (signal line). The well region 171 is connected to a third wiring (ground line). A second terminal of the thermoelectric conversion unit 105 is connected to a fourth wiring (reference bias line). A source electrode 178 of the MOS transistor 107 is connected to the fourth wiring via the thermoelectric conversion unit 105. Therefore, in the MOS transistor 107, by applying a voltage to the gate electrodes 176 of multiple pixel units 2 via the second wiring, it is possible to read out the output voltages of the pixel units 2 via the first wiring. The read-out output voltages of the pixel units 2 correspond to the detection signals of the infrared sensor chip 1.

[0040] (2.2) IC chip 4, the IC chip 51 is mounted on the front surface 310 of the package body 31. The IC chip 51 is mounted on the front surface 310 of the package body 31 side by side with the infrared sensor chip 1 (side by side in the second direction D2). The IC chip 51 includes a signal processing circuit 510 that processes the detection signal of the infrared sensor chip 1. That is, the IC chip 51 is configured to process the detection signal of the infrared sensor chip 1.

[0041] 8, the signal processing circuit 510 includes an amplifier circuit 511, a multiplexer 512, an A / D conversion circuit 513, a calculation unit 514, a memory 515, and a control circuit 516. The amplifier circuit 511 amplifies the output voltage (detection signal) of the infrared sensor chip 1. The multiplexer 512 selectively inputs the output voltages of the thermoelectric conversion units 105 of the multiple pixel units 102 of the infrared sensor chip 1 to the amplifier circuit 511. The A / D conversion circuit 513 converts the output voltage of the infrared sensor chip 1 amplified by the amplifier circuit 511 into a digital value. The calculation unit 514 calculates the temperature of an object within the detection area of ​​the infrared sensor 100 using the digital value output from the A / D conversion circuit 513 in response to the output voltage of the infrared sensor chip 1. The detection area of ​​the infrared sensor 100 is determined by the shape of the lens 6 disposed on the light receiving surface side of the infrared sensor chip 1, etc. The memory 515 stores data and the like used for calculations in the calculation unit 514. The control circuit 516 controls the multiple MOS transistors 107 of the infrared sensor chip 1. Note that the circuit configuration of the signal processing circuit 510 is not limited to the configuration in FIG.

[0042] (2.3) Package As shown in FIGS. 1 to 4, the package 3 accommodates the infrared sensor chip 1 and the IC chip 51.

[0043] The package 3 includes a package body 31 and an outer cap 32 .

[0044] The package body 31 has a rectangular plate-like outer periphery when viewed from above in the thickness direction. The thickness direction of the package body 31 is along the first direction D1 (front-rear direction). The package body 31 includes, for example, an insulating substrate made of epoxy glass and a conductive portion for wiring provided on the insulating substrate. Here, the conductive portion includes electrode pads 80, 81, and 82 (see FIG. 9), a conductor wiring portion 53, a ground wiring portion 400, a connection terminal 52, and a ground terminal 40 (see FIG. 1). The package body 31 is formed, for example, from a glass cloth-based epoxy resin copper-clad laminate. However, the package body 31 is not limited to this, and may be a ceramic substrate or the like.

[0045] As shown in FIG. 9, the front surface 310 of the package body 31 includes a first region 311 to a sixth region 316 and a remaining region 317.

[0046] The first region 311 is a region for disposing the infrared sensor chip 1. The first region 311 has a rectangular shape when viewed from above in the thickness direction of the package body 31.

[0047] The second region 312 is a region for placing the IC chip 51. The second region 312 has a rectangular shape when viewed from above in the thickness direction of the package body 31.

[0048] The third region 313 is a region for mainly arranging a plurality of electrode pads 81 for connecting wires connected to the infrared sensor chip 1. In the example of Fig. 9, there are two third regions 313 on the front surface 310 of the package body 31. The two third regions 313 are located on both sides of the first region 311 (infrared sensor chip 1) in the third direction D3. A plurality of electrode pads 81 (eight in total) are provided in the two third regions 313.

[0049] The fourth region 314 is a region for mainly arranging a plurality of electrode pads 82 for connecting wires connected to the IC chip 51. In the example of FIG. 9, there are two fourth regions 314 on the front surface 310 of the package body 31. The two fourth regions 314 are located on both sides of the second region 312 (IC chip 51) in the third direction D3. One of the two fourth regions 314 (the lower fourth region 314 in FIG. 9) extends from one end in the second direction D2 (the left end in FIG. 9) toward the other of the two fourth regions 314 (upward in FIG. 9) along the third direction D3. A plurality of electrode pads 82 (22 in total) are provided in the two fourth regions 314.

[0050] The fifth region 315 is a region for joining the inner cap 4 to the package body 31. In the example of Fig. 9, there are two fifth regions 315 on the front surface 310 of the package body 31. The two fifth regions 315 are located on both sides of the first region 311 and the second region 312 (the infrared sensor chip 1 and the IC chip 51) in the second direction D2. A plurality of electrode pads 80 (six in total) are provided in the two fifth regions 315.

[0051] The sixth region 316 is a region for joining the outer cap 32 to the package body 31. The sixth region 316 is a frame-like shape (a rectangular frame with curved corners) large enough to surround the first region 311 to the fifth region 315 as a whole.

[0052] The package body 31 is, for example, a multi-layer substrate, and in this example, a four-layer substrate. That is, in the package body 31, the conductive portions are formed in four layers: the outermost layer (the front surface 310 of the package body 31), a first intermediate layer, a second intermediate layer, and a back surface. The conductive portions of each layer are connected by via conductors. In FIG. 9, the portion of the conductive portion (including electrode pads 80, 81, and 82) provided on the front surface 310 (the outermost layer) of the package body 31 is indicated by hatching. Also, as shown in FIG. 1, the connection terminal 52 and the ground terminal 40 of the conductive portion are provided on the back surface of the package body 31. The connection terminal 52 is a terminal connected to an external electric circuit. The ground terminal 40 is a terminal connected to an external ground (for example, the ground potential of a motherboard on which the infrared sensor 100 is mounted).

[0053] The infrared sensor chip 1 is mounted in a first region 311 on the front surface 310 of the package body 31. In the infrared sensor 100, a plurality of pad electrodes of the infrared sensor chip 1 are electrically connected to a plurality of electrode pads 81 by wires using, for example, a wire bonding technique. The plurality of electrode pads 81 are individually connected to some of the plurality of electrode pads 82 via conductive parts wired inside the package body 31 (for example, the outermost layer or the first intermediate layer) (see FIG. 9). A detection signal of the infrared sensor chip 1 is output to the IC chip 51 via these electrode pads 81, 82, the conductive parts, wires, etc.

[0054] The IC chip 51 is mounted in the second region 312 on the front surface 310 of the package body 31. In the infrared sensor 100, a plurality of pad electrodes of the IC chip 51 are electrically connected to a plurality of electrode pads 82 by wires, for example, using a wire bonding technique. Another portion of the plurality of electrode pads 82 (a portion of the electrode pads 82 not connected to the electrode pads 81) is individually connected to a plurality of connection terminals 52 (see FIG. 1 ; only one is shown in FIG. 1 ) via conductive portions (conductor wiring portions 53) wired inside the package body 31 (for example, the first intermediate layer or the second intermediate layer). That is, the IC chip 51 is electrically connected to the connection terminals 52 via the conductor wiring portions 53 (conductive portions). In short, the infrared sensor 100 includes an electric circuit 5 including the IC chip 51, the connection terminals 52, and the conductor wiring portions 53.

[0055] The outer cap 32 is mounted on the sixth region 316 on the front surface 310 of the package body 31. The outer cap 32 is electrically conductive. Here, the outer cap 32 is made of metal, for example, stainless steel (SUS). As shown in FIG. 3, the outer cap 32 is in the shape of a hollow rectangular box with an open rear surface. The outer cap 32 is attached to the package body 31 so as to cover the infrared sensor chip 1 and the IC chip 51. The corners and sides of the outer cap 32 are chamfered. A rectangular frame-shaped flange 321 extending outward is formed on the edge (rear edge) of the opening of the outer cap 32.

[0056] The outer cap 32 is fixed to the package body 31 by joining the flange 321 to the sixth region 316 by a first bonding portion 71 (see FIG. 10). In the outer cap 32, the flange 321 is joined to the sixth region 316 of the package body 31 around the entire periphery. The first bonding portion 71 has electrical insulation properties. The first bonding portion 71 is formed, for example, from a first adhesive having electrical insulation properties. The first adhesive may be, for example, a thermosetting adhesive that is temporarily hardened by ultraviolet light.

[0057] The outer cap 32 is electrically insulated from the conductive parts (the conductor wiring part 53 and the ground wiring part 400) of the package body 31. The outer cap 32 is also electrically insulated from the infrared sensor chip 1. The outer cap 32 is also electrically insulated from the IC chip 51.

[0058] The outer cap 32 has a tubular portion 322 on its front wall. The tubular portion 322 is formed on the front wall of the outer cap 32 at a portion corresponding to the position of the infrared sensor chip 1 in the first direction D1 (in front of the infrared sensor chip 1). The tubular portion 322 protrudes toward the outside (forward) of the package 3. The tubular portion 322 has, for example, a cylindrical shape whose diameter decreases toward the front (as it becomes farther away from the infrared sensor chip 1) (see FIGS. 2 and 3). The tubular portion 322 is formed by, for example, drawing. An opening 320 is formed at the front end of the tubular portion 322. The opening 320 has a circular shape. The opening 320 is a hole for transmitting infrared light to be detected by the infrared sensor chip 1. In short, the outer cap 32 has a function of transmitting infrared light to be detected by the infrared sensor chip 1.

[0059] In the outer cap 32, a lens 6 is disposed at the base end (rear end) of the cylindrical portion 322. That is, the infrared sensor 100 includes the lens 6 disposed in front of the infrared sensor chip 1. The lens 6 covers the opening at the rear end of the cylindrical portion 322. The lens 6 is made of, for example, silicon. The lens 6 is, for example, an aspherical lens. The lens 6 focuses infrared light to be detected by the infrared sensor chip 1 onto the infrared sensor chip 1. The lens 6 is bonded to the outer cap 32 by, for example, a conductive material. The infrared sensor 100 includes the lens 6, which improves the accuracy of infrared light detection by the infrared sensor chip 1.

[0060] The outer cap 32 is fixed to the package body 31 to form the package 3 having an airtight internal space.

[0061] Since the outer cap 32 is provided with the cylindrical portion 322, foreign matter is less likely to come into contact with the lens 6 than in a case where the cylindrical portion 322 is not provided, and contamination of the lens 6 is prevented. Therefore, in the infrared sensor 100, it is possible to suppress a decrease in the detection accuracy of the infrared sensor chip 1 caused by contamination of the lens 6.

[0062] Furthermore, in the infrared sensor 100 of this embodiment, by appropriately setting the size of the opening 320, it is possible to impart the function of a so-called "optical diaphragm."

[0063] As described above, the outer cap 32 is made of metal. Therefore, it is possible to improve the mechanical strength compared to an outer cap made of, for example, resin. Furthermore, a metal outer cap 32 can more easily release absorbed heat than a resin outer cap, making it possible to stabilize the temperature inside the package 3.

[0064] As shown in Figure 10, an insulating coating 90 is formed on the outer surface of the outer cap 32. In other words, the infrared sensor 100 includes the insulating coating 90 provided on the outer surface of the outer cap 32. The insulating coating 90 is formed so as to cover the entire outer surface of the outer cap 32. The insulating coating 90 is made of, for example, a liquid crystal polymer. The insulating coating 90 is formed on the outer surface of the outer cap 32 by, for example, painting. By forming the insulating coating 90 on the outer cap 32, the electrical insulation performance of the outer cap 32 can be improved.

[0065] The thickness of the insulating coating 90 is smaller than the thickness of the outer cap 32. For example, the thickness of the insulating coating 90 is smaller than the thickness of the outer cap 32 by about one order of magnitude. Therefore, even if the insulating coating 90 is provided on the outer cap 32, the effect on the temperature stability inside the package 3 is small.

[0066] The insulating coating 90 may be paint having an appropriate color. By forming the colored insulating coating 90 on the outer surface of the outer cap 32, the design of the infrared sensor 100 can be improved.

[0067] (2.4) Inner cap The inner cap 4 is electrically conductive. Here, the inner cap 4 is made of a metal, particularly a metal with high thermal conductivity, such as copper. The inner cap 4 is mounted on the fifth region 315 on the front surface 310 of the package body 31.

[0068] 1, 3, and 4, the inner cap 4 integrally includes a front plate 41, a pair of first side plates 42, a pair of second side plates 43, and a pair of mounting plates 44. The inner cap 4 is formed, for example, by punching and bending a single metal plate (copper plate).

[0069] The front plate 41 has a rectangular plate shape and is sized to cover both the first area 311 and the second area 312 (i.e., both the infrared sensor chip 1 and the IC chip 51) when viewed from the first direction D1 (front-rear direction).

[0070] The pair of first side plates 42 extend rearward from both sides of the front plate 41 in the second direction D2. The front plate 41 and the first side plates 42 are connected by a curved surface.

[0071] The pair of mounting plates 44 extend laterally (outside) from the leading ends (rear ends) of the pair of first side plates 42. The first side plates 42 and the mounting plates 44 are connected by a curved surface. The inner cap 4 is fixed to the package body 31 by bonding the pair of mounting plates 44 to the two fifth regions 315 respectively by second bonding portions 72 (see FIG. 10). The second bonding portions 72 are conductive. The second bonding portions 72 are formed from, for example, a second adhesive having conductivity. The second adhesive may be, for example, silver paste.

[0072] With the inner cap 4 attached to the package body 31, the front plate 41 is located in front of the infrared sensor chip 1 and the IC chip 51. In particular, in the thickness direction of the package body 31, both the first region 311 and the second region 312 (i.e., both the infrared sensor chip 1 and the IC chip 51) are located within a projected area of ​​the outer periphery of the front plate 41. In short, the inner cap 4 is disposed between the package body 31 and the outer cap 32 so as to cover the front of the infrared sensor chip 1 and the IC chip 51.

[0073] As described above, the electrode pads 80 are provided in the fifth region 315. Therefore, when the mounting plate 44 is joined to the package body 31 by the second joint portions 72, the inner cap 4 is electrically connected to the electrode pads 80 via the second joint portions 72.

[0074] The electrode pad 80 is connected to the ground terminal 40 via a conductive portion (ground wiring portion 400) wired inside (for example, the first intermediate layer or the second intermediate layer) of the package body 31. That is, the inner cap 4 is electrically connected to the ground terminal 40 via the ground wiring portion 400 (conductive portion).

[0075] The pair of second side plates 43 extend rearward from both sides of the front plate 41 in the third direction D3. The length of the second side plate 43 (the length of protrusion from the front plate 41) is shorter than the length of the first side plate 42. Therefore, when the inner cap 4 is attached to the package body 31, there is a gap between the tip (rear end) of the second side plate 43 and the package body 31. In other words, the second side plate 43 has a so-called eave-like shape. The front plate 41 and the second side plate 43 are connected by a curved surface. There is a gap (a notch-shaped gap extending along the first direction D1) between the first side plate 42 and the second side plate 43.

[0076] 1 and 4, an opening 410 is formed in the front plate 41 in a portion facing the infrared sensor chip 1. As shown in FIGS. 1 and 3, the opening 410 is located between the opening 320 of the outer cap 32 and the infrared sensor chip 1. The opening 410 is a hole for transmitting infrared light to be detected by the infrared sensor chip 1. In short, the inner cap 4 has the function of transmitting infrared light to be detected by the infrared sensor chip 1.

[0077] Furthermore, the inner cap 4 is not in contact with the outer cap 32. In other words, the outer cap 32 is electrically insulated from the inner cap 4.

[0078] The infrared sensor 100 includes the inner cap 4, which allows a portion of the heat generated in the IC chip 51 to be transferred via the inner cap 4 to pixel units 102 of the infrared sensor chip 1 that are farthest from the IC chip 51. Therefore, in the infrared sensor 100, it is possible to prevent only the pixel units 102 close to the IC chip 51 from being affected by the heat generated by the IC chip 51, thereby reducing the uneven effect of the heat generated in the IC chip 51 on the infrared sensor chip 1.

[0079] Furthermore, in the infrared sensor 100, since the inner cap 4 is provided between the infrared sensor chip 1 and the outer cap 32, it is difficult for infrared rays from the outer cap 32 to reach the infrared sensor chip 1. Therefore, in the infrared sensor 100 of this embodiment, it is possible to reduce the effect of temperature fluctuations in the outer cap 32 on the infrared sensor chip 1, and to improve the detection accuracy of the infrared sensor chip 1.

[0080] Furthermore, the infrared sensor 100 can be provided with an electromagnetic shielding function by providing a metal inner cap 4. In particular, in the infrared sensor 100 of this embodiment, the inner cap 4 is connected to ground. Therefore, according to the infrared sensor 100, the electromagnetic waves traveling from the outside (front) of the infrared sensor 100 toward the infrared sensor chip 1 or the IC chip 51 can be reflected or absorbed by the inner cap 4, making it possible to block or reduce the electromagnetic waves.

[0081] (2.5) Electrical insulation performance The electrical insulation performance of the infrared sensor 100 of this embodiment will be described with reference to FIGS.

[0082] As described above, the outer cap 32 is electrically insulated from the inner cap 4 (ground) and the infrared sensor chip 1. Further, the outer cap 32 is electrically insulated from the IC chip 51. In the infrared sensor 100 of the present embodiment, in particular, the outer cap 32 is in a so-called floating state. Therefore, in the infrared sensor 100 of the present embodiment, even if the ground potential of the mother board fluctuates, the potential of the outer cap 32 located outside the infrared sensor 100 is less likely to fluctuate. Therefore, the infrared sensor 100 of the present embodiment can suppress the electrical influence on the surroundings.

[0083] Furthermore, the infrared sensor 100 of the present embodiment satisfies both the following first distance condition and second distance condition.

[0084] The first distance condition is a condition that the shortest distance R1 between the outer cap 32 and the inner cap 4 is smaller than the shortest distance R3 between the outer cap 32 and the electric circuit 5 (R1 < R3). The shortest distance R3 between the outer cap 32 and the electric circuit 5 is the distance between the portion closest to the outer cap 32 among the IC chip 51, the connection terminal 52, and the conductor wiring portion 53 (for example, a part of the conductor wiring portion 53) and the outer cap 32.

[0085] The second distance condition is a condition that the shortest distance R2 (see FIG. 10) between the outer cap 32 and the ground wiring portion 400 is smaller than the shortest distance R3 between the outer cap 32 and the electric circuit 5 (R2 < R3).

[0086] The infrared sensor 100 satisfies the first distance condition. Furthermore, in the infrared sensor 100, the gas (e.g., air) present between the outer cap 32 and the inner cap 4 has a lower dielectric strength than the insulating substrate (epoxy glass) of the package body 31 present between the outer cap 32 and the electric circuit 5. Therefore, in the infrared sensor 100, the insulation resistance between the outer cap 32 and the inner cap 4 is lower than the insulation resistance between the outer cap 32 and the electric circuit 5. Therefore, even if a short circuit occurs between the outer cap 32 and another component of the infrared sensor 100, the outer cap 32 will short-circuit with the inner cap 4, not with the electric circuit 5. Since the infrared sensor 100 satisfies the first distance condition, the electric circuit 5 is less likely to suffer from a malfunction, such as a short circuit. In other words, the infrared sensor 100 achieves a fail-safe function.

[0087] The infrared sensor 100 satisfies the second distance condition. Furthermore, in the infrared sensor 100, the insulating substrate (epoxy glass) of the package body 31 is interposed between the outer cap 32 and the ground wiring part 400 and between the outer cap 32 and the electric circuit 5. Therefore, in the infrared sensor 100, the insulation resistance between the outer cap 32 and the ground wiring part 400 is smaller than the insulation resistance between the outer cap 32 and the electric circuit 5. Therefore, even if a short circuit occurs between the outer cap 32 and another component of the infrared sensor 100, the outer cap 32 will short with the ground wiring part 400 rather than with the electric circuit 5. In this way, since the infrared sensor 100 satisfies the second distance condition, the electric circuit 5 is less likely to suffer from problems such as a short circuit.

[0088] In addition, the infrared sensor 100 of the present embodiment satisfies the following third distance condition. The third distance condition is a condition that the shortest distance R1 between the outer cap 32 and the inner cap 4 is smaller than the shortest distance R2 between the outer cap 32 and the ground wiring portion 400 (R1 < R2). By the infrared sensor 100 satisfying the third distance condition, even if a short circuit occurs between the outer cap 32 and other components in the infrared sensor 100, the outer cap 32 will short-circuit with the inner cap 4 rather than the ground wiring portion 400. As a result, it becomes difficult for insulation breakdown to occur in the package body 31, and it becomes possible to protect the package body 31.

[0089] In addition, in the infrared sensor 100 of the present embodiment, the shortest distance R1 between the outer cap 32 and the inner cap 4 is set to a value of 0.3 mm or more and 1.0 mm or less.

[0090] Since the shortest distance R1 is equal to or greater than the lower limit value (0.3 mm) of this range, the infrared sensor 100 can have predetermined withstand voltage performance. Generally, there is a relationship known as Paschen's law between the distance between a pair of electrodes (electrode distance) and the magnitude of the voltage at which discharge can occur between the pair of electrodes when a voltage is applied between the pair of electrodes (discharge start voltage), as shown in FIG. 11. In FIG. 11, A1 shows the curve of the discharge start voltage when the medium between the pair of electrodes is air (atmospheric pressure 1 atm). From FIG. 11, it can be seen that by setting the shortest distance R1 to 0.3 mm or more, the discharge start voltage can be set to 1.5 kV or more, and the withstand voltage performance specified in JIS C 6950-1:2012 can be satisfied.

[0091] In addition, since the shortest distance R1 is equal to or less than the upper limit value (1.0 mm) of this range, it becomes possible to suppress the increase in size of the infrared sensor 100.

[0092] More preferably, the shortest distance R1 is 0.4 mm or more and 0.7 mm or less. Even more preferably, the shortest distance R1 is 0.5 mm.

[0093] As described above, in the infrared sensor 100 of this embodiment, the outer cap 32 is electrically insulated from the inner cap 4 and the infrared sensor chip 1, and the inner cap 4 is electrically connected to the ground terminal 40. Therefore, in the infrared sensor 100 of this embodiment, even if the ground potential of the motherboard fluctuates, the potential of the outer cap 32 located outside the infrared sensor 100 is unlikely to fluctuate. In short, the infrared sensor 100 of this embodiment can suppress electrical influences on the surroundings.

[0094] (3) Variations The above-described embodiment is merely one of various embodiments of the present disclosure. The above-described embodiment can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Below, modifications of the above-described embodiment are listed. The modifications described below can be applied in appropriate combination with the above-described embodiment and other modifications. Hereinafter, the above-described embodiment may be referred to as a "basic example."

[0095] In one variation, the infrared sensor 100 may further include a thermistor. The thermistor is arranged near the infrared sensor chip 1 to detect the temperature of the cold junction T2 of the infrared sensor chip 1. For example, the thermistor is mounted on the front surface 310 of the package body 31 side by side with the infrared sensor chip 1 in the third direction D3. The IC chip 51 is configured to process the output signal of the thermistor in addition to the detection signal of the infrared sensor chip 1.

[0096] In one variation, the lens 6 may be attached to the inner cap 4 instead of the outer cap 32. In this case, for example, the opening 320 of the outer cap 32 is closed by a member that transmits infrared rays (e.g., a silicon substrate, a polyethylene molding, etc.).

[0097] In one modified example, the connection terminals 52 may be arranged inside the projection area of ​​the sixth area 316 in the first direction D1 (front-rear direction) (inside the area surrounded by the sixth area 316). In other words, the connection terminals 52 may be arranged inside the projection area of ​​the internal space of the package 3 in the first direction D1.

[0098] In one modified example, the entire conductor wiring portion 53 may be disposed inside the projection area of ​​the sixth region 316 in the first direction D1 (within the area surrounded by the sixth region 316). In other words, the conductor wiring portion 53 may be disposed inside the projection area of ​​the internal space of the package 3 in the first direction D1.

[0099] (4) Aspects The following aspects are disclosed from the above-described embodiments and modifications.

[0100] The infrared sensor (100) of the first embodiment includes a package body (31), an infrared sensor chip (1), an outer cap (32), and an inner cap (4). The infrared sensor chip (1) is mounted on the front surface (310) of the package body (31). The outer cap (32) is conductive. The outer cap (32) is attached to the package body (31) so as to cover the front of the infrared sensor chip (1). The outer cap (32) has a function of transmitting infrared light to be detected by the infrared sensor chip (1). The inner cap (4) is conductive. The inner cap (4) is disposed between the package body (31) and the outer cap (32) so as to cover the front of the infrared sensor chip (1). The inner cap (4) has a function of transmitting infrared light to be detected by the infrared sensor chip (1). The package body (31) includes a ground terminal (40). The ground terminal (40) is connected to an external ground. The outer cap 32 is electrically insulated from the inner cap 4 and the infrared sensor chip 1. The inner cap 4 is electrically connected to the ground terminal 40.

[0101] According to this aspect, even if the ground potential of the motherboard fluctuates, the potential of the outer cap 32 that constitutes the outside of the infrared sensor 100 is unlikely to fluctuate. In short, this aspect has the advantage of being able to suppress (reduce) the electrical influence of the infrared sensor 100 on the surroundings.

[0102] The infrared sensor (100) of the second embodiment is the same as that of the first embodiment, but includes an electric circuit (5). The electric circuit (5) includes an IC chip (51), a connection terminal (52), and a conductor wiring portion (53). The IC chip (51) processes the detection signal of the infrared sensor chip (1). The connection terminal (52) outputs the output signal of the IC chip (51) to the outside. The conductor wiring portion (53) electrically connects the IC chip (51) to the connection terminal (52). The insulation resistance between the outer cap (32) and the inner cap (4) is smaller than the insulation resistance between the outer cap (32) and the electric circuit (5).

[0103] According to this embodiment, it is possible to prevent malfunctions in the electric circuit (5).

[0104] The infrared sensor (100) of the third embodiment is the same as that of the first embodiment, but includes an electric circuit (5). The electric circuit (5) includes an IC chip (51), a connection terminal (52), and a conductor wiring portion (53). The IC chip (51) processes the detection signal of the infrared sensor chip (1). The connection terminal (52) outputs the output signal of the IC chip (51) to the outside. The conductor wiring portion (53) electrically connects the IC chip (51) to the connection terminal (52). The shortest distance (R1) between the outer cap (32) and the inner cap (4) is shorter than the shortest distance (R3) between the outer cap (32) and the electric circuit (5).

[0105] According to this embodiment, it is possible to prevent malfunctions in the electric circuit (5).

[0106] The infrared sensor (100) of the fourth aspect is the same as that of the third aspect, but includes a ground wiring portion (400). The ground wiring portion (400) electrically connects the inner cap (4) and the ground terminal (40). The shortest distance (R1) between the outer cap (32) and the inner cap (4) is shorter than the shortest distance (R2) between the outer cap (32) and the ground wiring portion (400).

[0107] According to this embodiment, it is possible to prevent malfunctions in the electric circuit (5).

[0108] In the infrared sensor (100) of the fifth aspect, in any one of the first to fourth aspects, the shortest distance (R1) between the outer cap (32) and the inner cap (4) is 0.3 mm or more and 1.0 mm or less.

[0109] According to this embodiment, it is possible to improve the voltage resistance performance of the infrared sensor (100).

[0110] The infrared sensor (100) of a sixth aspect is any one of the first to fifth aspects, and further includes a lens (6). The lens (6) is disposed in front of the infrared sensor chip (1). The lens (6) focuses infrared light to be detected onto the infrared sensor chip (1).

[0111] According to this aspect, it is possible to improve the accuracy of infrared detection by the infrared sensor chip (1).

[0112] The infrared sensor (100) of a seventh aspect is the infrared sensor (100) of any one of the first to sixth aspects, further comprising an insulating coating (90). The insulating coating is provided on the outside of the outer cap (32).

[0113] According to this embodiment, the electrical insulating performance of the outer cap (32) can be improved. [Explanation of symbols]

[0114] 1 Infrared sensor chip 31 Package body 310 Front 32 Outer cap 4 Inner cap 40 Ground terminal 400 Ground wiring section 5 Electrical Circuits 51 IC chip 52 Connection terminal 53 Conductor wiring section 6 Lenses 90 Insulating coating 100 Infrared Sensor R1 Shortest distance R2 Shortest distance R3 Shortest distance

Claims

1. A package body, an infrared sensor chip mounted on the front surface of the package body; an outer cap that is electrically conductive and has a function of transmitting infrared light to be detected by the infrared sensor chip, and is attached to the package body so as to cover a front side of the infrared sensor chip; The package body and the outer cap are electrically conductive and have a function of transmitting infrared light to be detected by the infrared sensor chip, and the package body and the outer cap are connected to cover the front of the infrared sensor chip. an inner cap disposed between the an electric circuit including an IC chip that processes a detection signal from the infrared sensor chip, a connection terminal that outputs an output signal from the IC chip to the outside, and a conductor wiring portion that electrically connects the IC chip and the connection terminal; A ground wiring portion; Equipped with the package body includes a ground terminal connected to an external ground; the ground wiring portion electrically connects the inner cap and the ground terminal, the outer cap is electrically insulated from the inner cap and the infrared sensor chip; the inner cap is electrically connected to the ground terminal; the shortest distance between the outer cap and the inner cap is smaller than the shortest distance between the outer cap and the electrical circuit; the shortest distance between the outer cap and the ground wiring portion is shorter than the shortest distance between the outer cap and the electric circuit; Infrared sensor.

2. The shortest distance between the outer cap and the inner cap is 0.3 mm or more and 1.0 mm or less.

2. The infrared sensor according to claim 1.

3. The device further comprises a lens disposed in front of the infrared sensor chip and configured to focus the infrared light to be detected onto the infrared sensor chip.

3. The infrared sensor according to claim 1 or 2.

4. The outer cap further comprises an insulating coating having electrical insulation properties provided on the outer surface thereof. The infrared sensor according to any one of claims 1 to 3.

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