Source: http://www.patentgenius.com/patent/8710443.html
Timestamp: 2018-04-23 21:22:41
Document Index: 786684195

Matched Legal Cases: ['Application No. 2011', 'Application No. 2011', 'art 102', 'art 102', 'art 102', 'art 210', 'art 210', 'art 102', 'art 102', 'art 102', 'art 102', 'art 102', 'art 102', 'art 420', 'art 430', 'art 440', 'art 450', 'art 460', 'art 420', 'art 430', 'art 430', 'art 440', 'art 430', 'art 420', 'art 450', 'art 460', 'art 460', 'art 730', 'art 740', 'art750', 'art 760', 'art 770', 'art 730', 'art 730', 'art 1050', 'art 1050', 'art 530', 'art 530', 'art 530', 'art 530']

Pyroelectric detector, pyroelectric detection device, and electronic instrument - Patent # 8710443 - PatentGenius
8710443 Pyroelectric detector, pyroelectric detection device, and electronic instrument
Foreign Patent Documents: 0827216; 10-104062
Abstract: A pyroelectric detector includes a substrate, a support member, a spacer member, and a pyroelectric detecting element. The spacer member supports the support member over the substrate with a cavity part being formed therebetween. The pyroelectric detecting element includes a first electrode mounted on the support member, a second electrode, and a pyroelectric body between the first and second electrodes. The support member includes an insulating layer, a first wiring layer disposed on a side of the second surface of the support member with respect to the insulating layer, and a first plug passing through the insulating layer at a position where the pyroelectric body and the first wiring layer overlap in plan view to connect the first wiring layer with the first electrode.
1. A pyroelectric detector comprising: a substrate; a support member including a first surface and a second surface opposite from the first surface; a spacer memberconnected to the substrate and supporting the support member so that a cavity part is formed between the substrate and the second surface of the support member; and a pyroelectric detecting element supported on the first surface of the support member,the pyroelectric detecting element including a first electrode mounted on the support member, a second electrode opposed to the first electrode, and a pyroelectric body arranged between the first and second electrodes, the support member including aninsulating layer, a first wiring layer disposed on a side of the second surface of the support member with respect to the insulating layer, and a first plug passing through the insulating layer at a position where the pyroelectric body and the firstwiring layer overlap in plan view to connect the first wiring layer with the first electrode.
2. The pyroelectric detector according to claim 1, wherein the first electrode includes two metal layers, and a metal oxide layer sandwiched between the two metal layers, the metal oxide layer having a lower thermal conductivity than the metallayers.
3. The pyroelectric detector according to claim 2, wherein the first electrode, the second electrode, and the pyroelectric body are preferentially oriented in a prescribed crystal plane, the first electrode has a seed layer connected to thepyroelectric body and preferentially oriented in the prescribed crystal plane, an orientation control layer formed on a side of the first surface with respect to the seed layer and preferentially oriented in the prescribed crystal plane, and a reducinggas barrier layer arranged between the seed layer and the orientation control layer, the reducing gas barrier layer having barrier properties with respect to a reducing gas, the seed layer and the orientation control layer being the two metal layers, andthe reducing gas barrier layer being the metal oxide layer.
4. A pyroelectric detection device comprising: a plurality of the pyroelectric detectors according to claim 3 arranged two-dimensionally along two intersecting axes.
5. An electronic instrument comprising: the pyroelectric detection device according to claim 4.
6. An electronic instrument comprising: the pyroelectric detector according to claim 3.
8. An electronic instrument comprising: the pyroelectric detection device according to claim 7.
9. An electronic instrument comprising: the pyroelectric detector according to claim 2.
10. The pyroelectric detector according to claim 1, wherein the first wiring layer includes one or more layers, the first electrode includes one or more layers, and a thermal conductivity of one of the layers of the first wiring layer connectedto the first plug is lower than a thermal conductivity of one of the layers of the first electrode connected to the first plug.
11. A pyroelectric detection device comprising: a plurality of the pyroelectric detectors according to claim 10 arranged two-dimensionally along two intersecting axes.
12. An electronic instrument comprising: the pyroelectric detection device according to claim 11.
13. An electronic instrument comprising: the pyroelectric detector according to claim 10.
14. The pyroelectric detector according to claim 1, wherein the pyroelectric detecting element further includes a second insulating layer covering the first electrode, the second electrode, and the pyroelectric body, a second electrode wiringlayer formed over the second insulating layer and connected to the second electrode, and an intermediate wiring layer formed on the first surface of the support member and connected to the second electrode wiring layer, and the support member furtherincludes a second wiring layer disposed on a side of the second surface side with respect to the insulating layer, and a second plug passing through the insulating layer at a position where the intermediate wiring layer and the second wiring layeroverlap in plan view to connect the second wiring layer with the intermediate wiring layer.
15. A pyroelectric detection device comprising: a plurality of the pyroelectric detectors according to claim 14 arranged two-dimensionally along two intersecting axes.
16. An electronic instrument comprising: the pyroelectric detection device according to claim 15.
17. An electronic instrument comprising: the pyroelectric detector according to claim 14.
18. A pyroelectric detection device comprising: a plurality of the pyroelectric detectors according to claim 1 arranged two-dimensionally along two intersecting axes.
19. An electronic instrument comprising: the pyroelectric detection device according to claim 18.
20. An electronic instrument comprising: the pyroelectric detector according to claim 1.
This application claims priority to Japanese Patent Application No. 2011-037960 filed on Feb. 24, 2011. The entire disclosure of Japanese Patent Application No. 2011-037960 is hereby incorporated herein by reference.
The present invention relates to a pyroelectric detector, a pyroelectric detection device, and an electronic instrument.
Pyroelectric type infrared detectors are known to be thermal type detectors. Pyroelectric type infrared detectors utilize an effect whereby the pyroelectric body undergoes a change in spontaneous polarization level due to the change intemperature in the pyroelectric body in accordance with the amount of infrared light that is received (pyroelectric effect or pyroelectron effect), and infrared light is detected as a result of the generation of pyroelectric current (change in surfacecharge due to the change in polarization level) in both terminals of the pyroelectric body. The process for producing pyroelectric type infrared detectors is complicated in comparison to bolometer type infrared detectors, but they have the advantage ofsuperior detection sensitivity.
Pyroelectric type infrared detectors have infrared detecting elements that contain capacitors that are formed from a pyroelectric body that is connected to an upper electrode and a lower electrode. Various types of electrode and pyroelectricbody materials, as well as electrode wiring structures have been offered (see, Japanese Laid-Open Patent Application Publication No. 10-104062).
In addition, because the infrared detecting element is mounted on a membrane (support member), and a cavity is formed between the membrane and the substrate on which the infrared detector is formed, the infrared detecting element is thermallyisolated from the substrate.
It has also been contemplated to dispose a detector circuit on a substrate, and to connect the detector circuit to an infrared detector by wiring which is disposed over a membrane.
In accordance with a number of aspects of the present invention, there can be provided a pyroelectric detector, a pyroelectric detection device, and an electronic instrument which protect the wiring connected to the first electrode forelectrical stability, and which despite the electrical contact first electrode and the wiring being formed to sufficiently large size, require no expansion in surface area and are suitable for a high degree of integration.
A pyroelectric detector according to one aspect of the present invention includes a substrate, a support member, a spacer member and a pyroelectric detecting element. The support member includes a first surface and a second surface oppositefrom the first surface. The spacer member is connected to the substrate and supporting the support member so that a cavity part is formed between the substrate and the second surface of the support member. The pyroelectric detecting element issupported on the first surface of the support member, the pyroelectric detecting element including a first electrode mounted on the support member, a second electrode opposed to the first electrode, and a pyroelectric body arranged between the first andsecond electrodes. The support member includes an insulating layer, a first wiring layer disposed on a side of the second surface of the support member with respect to the insulating layer, and a first plug passing through the insulating layer at aposition where the pyroelectric body and the first wiring layer overlap in plan view to connect the first wiring layer with the first electrode.
According to this aspect of the present invention, the wiring connected to the first electrode can be formed by the first wiring and the first plug formed on the support member. Because the first plug is connected to the first wiring at aposition inside the support member and overlapping in plan view the capacitor where the first electrode and the pyroelectric body are stacked, the surface area of the element is not expanded in association with ensuring a contact region for connection ofthe first electrode and the wiring on the first surface of the support member. Therefore, a pyroelectric detector suitable for a high degree of integration can be provided. Because the wiring connected to the first electrode is protected by theinsulating layer, damage and short-circuiting of the wiring do not readily occur, and the pyroelectric detector is electrically stable.
According to another aspect of the present invention, the first electrode preferably includes two metal layers, and a metal oxide layer sandwiched between the two metal layers, the metal oxide layer having a lower thermal conductivity than themetal layers. Therefore, the amount of heat emitted from the first electrode into the first plug and the first wiring layer can be reduced by the metal oxide layer with lower thermal conductivity than the metal layers, and thermal isolation of thepyroelectric detecting element can be ensured.
According to another aspect of the present invention, the first electrode, the second electrode, and the pyroelectric body are preferably preferentially oriented in a prescribed crystal plane. The first electrode preferably has a seed layerconnected to the pyroelectric body and preferentially oriented in the prescribed crystal plane, an orientation control layer formed on a side of the first surface with respect to the seed layer and preferentially oriented in the prescribed crystal plane,and a reducing gas barrier layer arranged between the seed layer and the orientation control layer, the reducing gas barrier layer having barrier properties with respect to a reducing gas. The seed layer and the orientation control layer is preferablythe two metal layers, and the reducing gas barrier layer is preferably the metal oxide layer.
Therefore, the seed layer and the orientation control layer constitute the two metal layers, and the reducing gas barrier layer can serve concomitantly as the metal oxide layer for thermal insulation.
According to another aspect of the present invention, the first wiring layer preferably includes one or more layers, the first electrode preferably includes one or more layers, and a thermal conductivity of one of the layers of the first wiringlayer connected to the first plug is preferably lower than a thermal conductivity of one of the layers of the first electrode connected to the first plug.
Therefore, the amount of heat emitted from the first electrode into the first plug and the first wiring layer can be reduced by the first plug, and thermal isolation of the pyroelectric detecting element can be ensured.
According to another aspect of the present invention, the pyroelectric detecting element preferably further includes a second insulating layer covering the first electrode, the second electrode, and the pyroelectric body, a second electrodewiring layer formed over the second insulating layer and connected to the second electrode, and an intermediate wiring layer formed on the first surface of the support member and connected to the second electrode wiring layer. The support memberpreferably further includes a second wiring layer disposed on a side of the second surface side with respect to the insulating layer, and a second plug passing through the insulating layer at a position where the intermediate wiring layer and the secondwiring layer overlap in plan view to connect the second wiring layer with the intermediate wiring layer.
Therefore, the wiring connected to the second electrode can be formed to include the second wiring and the second plug formed on the support member. Because the wiring connected to the second electrode is protected by the insulating layer,damage and short-circuiting of the wiring do not readily occur, and the pyroelectric detector is more electrically stable.
A pyroelectric detection device according to another aspect of the present invention includes a plurality of the pyroelectric detectors according to any of the above described aspects arranged two-dimensionally along two intersecting axes. Thispyroelectric detection device has increased detection sensitivity in the pyroelectric detectors of each cell and can thus provide clear light (temperature) distribution images.
An electronic instrument in yet another aspect of the present invention has the pyroelectric detector or the pyroelectric detection device according to any of the above described aspects. By using one or a plurality of cells containing thepyroelectric detectors as a sensor, the invention is optimal for use in thermographic devices that output a light (heat) distribution image, automobile navigation or surveillance cameras, as well as analytical instruments (measurement instruments) foranalyzing (measuring) physical data related to an object, security instruments for detecting fire or heat, and factory automation (FA) instruments that are installed in factories and the like.
FIG. 1 is a schematic sectional view of a pyroelectric detector of one cell of a pyroelectric type infrared detection device according to an embodiment of the present invention.
FIG. 2 is a schematic plan view of a pyroelectric type infrared detection device according to an embodiment of the present invention.
FIG. 3 is a diagram showing a comparative example of a support member having a step.
FIG. 4 is an enlarged view of a support member and a capacitor of a pyroelectric type infrared detection device according to an embodiment of the present invention.
FIG. 5 is a block diagram of an infrared camera (electronic instrument) including a pyroelectric detector or a pyroelectric detection device.
FIG. 6 is a diagram showing an on-board assistance device (electronic instrument) that includes an infrared camera.
FIG. 7 is a diagram showing a vehicle having an infrared camera mounted at the front.
FIG. 8 is a diagram showing a security instrument (electronic instrument) that includes an infrared camera.
FIG. 9 is a diagram showing a detection area of a human sensor and the infrared camera of the security instrument shown in FIG. 8.
FIG. 10 is a diagram showing a controller used in a gaming instrument that includes the sensor device shown in FIG. 5.
FIG. 11 is a diagram showing a gaming instrument that includes the controller shown in FIG. 10.
FIG. 12 is a diagram showing a body temperature measurement device (electronic instrument) that includes an infrared camera.
FIG. 13 is a diagram showing an example of a configuration in which the sensor device of FIG. 5 is used as a terahertz sensor device in combination with a terahertz irradiation unit in a specific material inspection device (electronicinstrument).
FIGS. 14A and 14B are diagrams showing an example configuration of a pyroelectric detection device in which pyroelectric detectors are disposed two-dimensionally.
Preferred embodiments of the present invention are described in detail below. The present invention described in the claims is not unfairly limited by the embodiments described below, and the entireties of the configurations described in theembodiments are not necessarily essential in regard to means for solving the problems according to the present invention.
FIG. 2 shows a pyroelectric type infrared detection device (more broadly, a pyroelectric detection device) in which a plurality of pyroelectric type infrared detectors 200, each single cell of which comprises a support member 210 shown in FIG. 1and a pyroelectric detecting element 220 mounted thereupon, are arranged along two intersecting linear directions, e.g., in two orthogonal axial directions. The pyroelectric type infrared detection device may instead be constituted by a pyroelectrictype infrared detector of a single cell only. In FIG. 2, a plurality of posts 104 are erected on a substrate 100, and the pyroelectric type infrared detectors 200 of each of the single cells supported, for example, by two posts (spacer members) 104 arearranged in two orthogonal axial directions. The region taken up by the pyroelectric type infrared detector 200 of each of the single cells is, for example, 30.times.30 .mu.m.
As shown in FIG. 2, the pyroelectric infrared detector 200 comprises a support member (membrane) 210 that is supported on two posts 104, and an infrared detection element (more broadly, a pyroelectric detection element) 220. The region taken upby the pyroelectric infrared detection element 220 of a single cell is, for example 20.times.20 .mu.m.
The pyroelectric infrared detector 200 of a single cell is connected with the two posts 104 and is otherwise not in contact with anything else, with a cavity part 102 (refer to FIG. 1) being formed under the pyroelectric infrared detector 200. An opening 102A that is in communication with the cavity part 102 is disposed at the periphery of the pyroelectric infrared detector 200 as seen from a plan view. As a result, the pyroelectric infrared detector 200 of a single cell is thermally isolatedfrom the substrate 100 and pyroelectric infrared detectors 200 of other cells. In other words, the posts 104 function as spacer members for forming the cavity part 102 between the support member 210 and the substrate 100. The spacer member has aprescribed height over the substrate from the surface of the substrate toward the support member, and the member can connect with a part of a second surface of the support member and a part of the substrate, so that there is no contact between thesubstrate and the support member. In addition, the shape of the posts 104 that serve as spacer members is not limited to columns, and the spacer member may be formed in the shape of a frame, grid, or the like.
The support member 210 has a mounting part 210A whereby the infrared detection element 220 is mounted and supported, and two arms 210B that are linked to the mounting part 210A. The free ends of the two arms 210B are linked to the posts 104. The two arms 210B are thin and long and have extra length in order to thermally isolate the infrared detection element 220.
FIG. 2 shows a first wiring layer 214 and a second wiring layer 217 that are disposed on the support member 210. The first and second wiring layers 214, 217 extend along the arms 210B and connect to the circuit in the substrate 100 via theposts 104. The first and second wiring layers 214, 217 also are thin and long and have extra length in order to thermally isolate the infrared detection element 220.
FIG. 1 is a sectional view of the pyroelectric infrared detector 200 shown in FIG. 2. With the pyroelectric infrared detector 200, the cavity part 102 in FIG. 1 is embedded in a sacrificial layer (not shown) during the production process. Thissacrificial layer is present from prior to the step for forming the support member 210 and the pyroelectric infrared detection element 220 to after this step. The layer is removed by isotropic etching subsequent to the step for forming the pyroelectricinfrared detection element 220.
As shown in FIG. 1, the substrate 100 comprises a silicon substrate 110 and an insulating layer (e.g., SiO.sub.2) 120 that is on the silicon substrate 110. The posts 104 are formed by etching the insulating layer 120 and are formed ofSiO.sub.2, for example. The posts 104 and the wiring structure in the insulating layer 120, as shown in FIG. 1, are configured using a plurality of metal layers L1A to LIC and a plurality of plugs CNT, HLA, HLB, and HLC that connect thereto. Thiswiring is connected to a detection circuit that is formed on a well-known MOS transistor structure in the silicon substrate 110 shown in FIG. 1. The detection circuit can comprise a row selection circuit (row driver) and a read circuit that reads thedata from the detectors via the columns (described in reference to FIG. 14A below). The cavity part 102 is formed simultaneous to the posts 104 by etching the insulating layer 120. The opening 102A shown in FIG. 2 is formed by pattern-etching thesupport member 210.
The infrared detection element 220 that is mounted on a first surface 211A of the support member 210 includes a capacitor 230. The capacitor 230 comprises a pyroelectric body 232, a first electrode (lower electrode) 234 that is connected to thelower surface of the pyroelectric body 232, and a second electrode (upper electrode) 236 that is connected to the upper surface of the pyroelectric body 232. The first electrode 234 may also comprise a binding layer (not shown) that increases bindingwith the support member 210.
The capacitor 230 is covered by a first reducing gas barrier layer 240 that inhibits ingress of reducing gas (e.g., hydrogen, water vapor, OH groups, methyl groups) into the capacitor 230 in the steps after the formation of the capacitor 230. This is done because the pyroelectric body 232 (e.g., PZT) of the capacitor 230 is an oxide, and its oxygen is depleted when the oxide is reduced, leading to loss of the pyroelectric effect.
The first reducing gas barrier layer 240 can comprise a lower first barrier layer and an upper second barrier layer. The first barrier layer can be formed by film growth involving, for example, the sputtering of aluminum oxide, Al.sub.2O.sub.3. Because reducing gas is not used in sputtering, reduction of the capacitor 230 will not occur. The second hydrogen barrier layer can be formed by film growth involving, for example, atomic layer chemical vapor deposition (ALCVD) using aluminum oxide,Al.sub.2O.sub.3. Reducing gas is used in ordinary chemical vapor deposition (CVD), but the capacitor 230 is isolated from the reducing gas by the first barrier layer.
The total layer thickness of the first reducing gas barrier layer 240 is 50 to 70 nm, e.g., 60 nm. At this time, the first barrier layer that is formed by CVD is thicker than the second barrier layer that is formed by atomic layer chemicalvapor deposition (ALCVD), which is thinner, at 35 to 65 nm, e.g., 40 nm. In contrast, the second barrier layer that is formed by atomic layer chemical vapor deposition (ALCVD) can be thin and may be formed by film growth of, for example, aluminum oxide,Al.sub.2O.sub.3, at 5 to 30 nm, e.g., 20 nm. Atomic layer chemical vapor deposition (ALCVD) has superior embedding characteristics in comparison to sputtering or the like. The method thus can be utilized for the production of fine detail, and thereducing gas barrier properties can be enhanced by the first and second barrier layers. Moreover, the first barrier layer that is grown by a sputtering method is not as dense as the second barrier layer, which has the effect of decreasing thermaltransfer, thereby preventing dissipation of heat from the capacitor 230.
An interlayer insulating layer (second insulating layer) 250 is formed on the first reducing gas barrier layer 240. In general, when raw material gas (TEOS) for the interlayer insulating layer 250 undergoes a chemical reaction, reducing gassessuch as hydrogen gas or water vapor are generated. The first reducing gas barrier layer 240 that is provided at the periphery of the capacitor 230 protects the capacitor 230 from reducing gas that is generated during formation of the interlayerinsulating layer 250.
A second electrode (upper electrode) wiring layer 224 is disposed on the interlayer insulating layer 250. In other words, the interlayer insulating layer 250 insulates the second electrode wiring layer 224 from the first and second electrodes234, 236 in the capacitor 230. The interlayer insulating layer 250 functions as an electrically insulating body, whereas the pyroelectric body 232 functions as a dielectric body. A hole 252 and a hole 254 are formed in the interlayer insulating layer250 prior to formation of the electrode wiring. At this time, a contact hole is similarly formed in the first reducing gas barrier layer 240. The second electrode (upper electrode) 236 and the second electrode wiring layer 224 are made to be incontinuity by a plug 226 that is embedded in the hole 252.
A mediating conductive layer 238 that connects with the second electrode wiring layer 224 may be present on the first surface 211A of the support member 210. Due to a plug 228 that is embedded in the hole 254, continuity is produced between thesecond electrode (upper electrode) 236 and the mediating conductive layer 238. The mediating conductive layer 238 may be formed in the same structure as the first electrode 234 and in the same process as the first electrode 234.
If an interlayer insulating layer 250 is not present, then when the second electrode (upper electrode) wiring layer 224 are pattern-etched, the second barrier layer of the first reducing gas barrier layer 240 therebelow will be etched, and thebarrier properties will decrease. The interlayer insulating 250 is necessary in order to ensure the barrier properties of the first reducing gas barrier layer 240.
The interlayer insulating layer 250 preferably has a low hydrogen content. The interlayer insulating layer 250 is subjected to a degassing treatment by annealing. In this manner, the hydrogen content of the interlayer insulating layer 250 ismade to be lower than in the passivation layer 270 that covers the second electrode wiring layer 224.
The first reducing gas barrier layer 240 of the top surface of the capacitor 230 is closed and does not have a hole during formation of the interlayer insulating layer 250, and thus reducing gas does not enter into the capacitor 230 duringformation of the interlayer insulating layer 250. However, after formation of a hole in the first reducing gas barrier layer 240, the barrier properties deteriorate. A preferred example whereby this is prevented may involve adding a second reducing gasbarrier layer 260 that encompasses the first reducing gas barrier layer 240. The second reducing gas barrier layer 260 makes up for the degradation of barrier properties due to the deficiency in the first reducing gas barrier layer 240 resulting fromthe formation of the hole (second opening) 252. It is thus desirable for the second reducing gas barrier layer 260 to be formed so that it covers at least the plug 226 that fills the hole 252, but the layer may also be formed so as to cover the firstreducing gas barrier layer 240 in order to inhibit reducing gas wraparound.
The second reducing gas barrier layer 260 is formed on the second electrode wiring layer 224, and it is thus necessary to provide a thin film in order to inhibit the transfer of heat and release of heat. In addition, because the interlayerinsulating layer 250 has infrared absorption effects, it is preferable to facilitate the passage of infrared light (wavelength range 8 to 14 .mu.m) by producing the second reducing gas barrier layer 260 as a thin film.
To this end, in this embodiment, the second reducing gas barrier layer 260 is formed from aluminum oxide Al.sub.2O.sub.3 and is produced as a film that is thinner than the first reducing gas barrier layer 240. To this end, the second reducinggas barrier layer 260 is formed by e.g., atomic layer chemical vapor deposition (ALCVD), which allows the layer thickness to be adjusted at the level of the size of atoms. The layer thickness of the second reducing gas barrier layer 260 is 20 nm, forexample. As described above, atomic layer chemical vapor deposition (ALCVD) has superior embedding characteristics in comparison to sputtering and the like, and this method thus allows the production of fine detail and the formation of a dense layer atthe atomic level. The reducing gas barrier properties can thus be increased, even when a thin film is used. With normal CVD methods, a thick layer is produced, and infrared light transmittance is thus compromised. A silicon nitride Si.sub.3N.sub.4film is undesirable for the second reducing gas barrier layer 260, because it must be formed as a thick layer of 100 nm or greater, for example, in order to ensure reducing gas barrier properties.
An SiO.sub.2 or SiN passivation layer 270 is provided which covers the second electrode wiring layer 224. An infrared absorbing body (more broadly, a light-absorbing member) 280 is provided on the passivation layer 270 above the capacitor 230. The passivation layer 270 is also formed from SiO.sub.2 or SiN, but is preferably a different material that has higher etching selectivity relative to the lower passivation layer 270, due to the need for pattern etching the infrared absorbing body 280. Infrared light is incident from the direction of the arrow in FIG. 1 on the infrared absorbing body 280, and the infrared absorbing body 280 generates heat in accordance with the amount of absorbed infrared light. Because this heat is conducted to thepyroelectric body 232, the spontaneous polarization level of the capacitor 230 changes due to the heat, and infrared light can be detected by detecting the charge that is produced by spontaneous polarization. The infrared absorbing body 280 is notrestricted to being provided separately with respect to the capacitor 230; if present in the capacitor 230, a separate infrared absorbing body 280 need not be provided.
Although reducing gas is generated during CVD formation of the passivation layer 270 or the infrared absorbing body 280, the capacitor 230 is protected by the first reducing gas barrier layer 240 and the second reducing gas barrier layer 260.
A third reducing gas barrier layer 290 is furnished covering the outer surface of the infrared detector 200 which includes this infrared absorbing body 280. In order to increase the transmittance of infrared light (wavelength range of 8 to 14um) impinging on the infrared absorbing body 280, it is necessary for this third reducing gas barrier layer 290 to be formed thinner than the first reducing gas barrier layer 240, for example. For this reason, atomic layer chemical vapor deposition(ALCVD) is adopted. However, in order for the third reducing gas barrier layer 290 to function as an etching stop layer as described below, it is formed thicker than the second reducing gas barrier layer 260. In the present embodiment, for example, analuminum oxide Al.sub.2O.sub.3 film is formed with a thickness of 40 to 50 nm, e.g., 45 nm.
In addition, an etching stop layer 130 is used during isotropic etching of a sacrificial layer (not shown) that is embedded in the cavity part 102 during the process for producing the pyroelectric infrared detector 200. This etching stop layer130 is formed on the wall part that defines the cavity part 102 towards the substrate 100, specifically, the side wall 104A and the bottom wall 110A that define the cavity part 102. Similarly, an etching stop layer 140 is formed on the lower surface ofthe support member 210 as well. In this embodiment, the third reducing gas barrier layer 290 is formed from the same material as the etching stop layers 130, 140. In other words, the etching stop layers 130, 140 also have reducing gas barrierproperties. Aluminum oxide Al.sub.2O.sub.3 is formed into a film having a layer thickness of 20 to 50 nm by atomic layer chemical vapor deposition (ALCVD), and the etching stop layers 130, 140 are formed.
Because the etching stop layer 130 has reducing gas barrier properties, when isotropic etching of the sacrificial layer is carried out using fluoric acid in a reducing atmosphere, passage of reducing gas through the support member 210 andingress into the capacitor 230 can be inhibited. In addition, because the etching stop layer 140 that covers the substrate 100 has reducing gas barrier properties, reduction and degradation of the wiring or transistors of the circuits that are disposedin the substrate 100 can be inhibited.
As shown in FIG. 1, a post 104, a support member 210, and a pyroelectric infrared detection element 220 are layered on the substrate 100 sequentially from the bottom layer to the top layer. The pyroelectric infrared detection element 220 ismounted on the support member 210 on the first surface 211A, and the second surface 211B faces the cavity part 102.
As shown in FIG. 1, in the support member 210, the first layer member 212 on the first surface side is an SiO.sub.2 support layer (insulating layer). This SiO.sub.2 support layer 212 has a lower hydrogen content than, for example, the posts104, which are another SiO.sub.2 layer positioned below the SiO.sub.2 support layer 212. This is obtained by increasing the O.sub.2 flow rate during CVD layer film growth to a rate higher than in ordinary CVD methods for forming interlayer insulatinglayers, to decrease the hydrogen or moisture content in the layer. In this way, the SiO.sub.2 support layer 212 is a low-moisture layer with a hydrogen content that is lower than, for example, the posts 104 of the other SiO.sub.2 layer (secondinsulating layer).
When the hydrogen content of the SiO.sub.2 support layer 212 on the top-most layer of the support member 210 is low, the generation of reducing gas (hydrogen, water vapor) from the SiO.sub.2 support layer 212 itself can be inhibited, even whenexposed to high temperatures during heat treatment subsequent to the formation of the pyroelectric body 232. In this manner, it is possible to inhibit reducing species that enter the pyroelectric body 232 in the capacitor 230 from directly below thecapacitor 230 (from the side of the support member 210), and it is possible to minimize the incidence of oxygen deficiency in the pyroelectric body 232.
Although the water content of, for example, the post 104 which is another SiO.sub.2 layer that is disposed below the SiO.sub.2 support layer 212 can also act as a reducing species, because it is isolated from the capacitor 230, its degree ofinfluence is smaller than that of the SiO.sub.2 support layer 212. However, because the water content of the post 104 can also act as a reducing species, it is preferable to form a layer having reducing gas barrier properties in the support member 210that is disposed below the SiO.sub.2 support layer 212. A detailed structure of a support member 210 that includes this feature is described below.
In other words, in this embodiment, the support member 210 can warp when formed from a single material, and is produced by layering a plurality of different materials. Specifically, the member can be formed from a first layer member 212 havingthe form of an oxide layer (SiO.sub.2) and a second layer member 213 having the form of a nitride layer (e.g., Si.sub.3N.sub.4).
For example, residual contraction stress arising in the first layer member 212 and residual tensile stress arising in the second layer member 213 act in directions whereby they cancel each other out. As a result, it is possible to additionallydecrease or eliminate residual stress in the support member 210 as a whole.
Here, the nitride layer (e.g., Si.sub.3N.sub.4) that forms the second layer member 213 has reducing gas barrier properties. As a result, a function for blocking reduction-impeding elements that enter into the pyroelectric body 232 of thecapacitor 230 from the support member 210 can be present in the support member 210 itself. For this reason, even with SiO.sub.2 layers having high hydrogen content that are present below the second layer member 213, the ingress of reducing species(hydrogen, water vapor) into the pyroelectric body 232 can be inhibited by the second layer member 213 having reducing gas barrier properties.
The support member 210 includes a first wiring layer 214 disposed to the second surface 211B side from the first layer member 212 which is an insulating layer; a first hole 215 formed passing through the first layer member 212 at a positionfacing the first electrode 234 and the first wiring layer 214 respectively, the position being in opposition to the capacitor 230; and a first plug 216 embedded in the first hole 215.
According to the present embodiment, the wiring connected to the first electrode 234 can be formed by the first wiring layer 214 and the first plug 216 formed in the support member 210. The first plug 216 is formed in the support member 210 ata position in opposition to the capacitor 230, and accordingly there is no expansion in the surface area of the element for the purpose of the wiring connected to the first electrode 234. Therefore, a pyroelectric detector suitable for a high degree ofintegration can be provided.
In addition, because the wiring that connects to the first electrode 234 leads out to the support member 210 side via the first plug 216, steps are not formed in the pyroelectric detecting element 220 or the support member 210 by the wiringleading to the first electrode 234 (refer to FIG. 1). By ensuring the planarity of the support member 210, the precision with which the resist is formed during formation of the support member 210 in the production process is increased, and the shapeprocessability of the support member 210 is improved.
In preferred practice, a material with high step coverage (step coatability), for example, tungsten (W) or the like is used for the first plug 216. The reason is that because the first surface 211A of the support member 210 influences theorientation of the capacitor, planarity is required.
FIG. 3 shows the etching step of a comparative example. A wiring layer 300 is formed on the support member 210, and a passivation layer 301 is then formed on the wiring layer 300. Due to the presence of the wiring layer 300, a step isproduced, and the passivation layer 301 is not planar. Thus, the precision with which the resist 302 is formed on the passivation layer 301 is compromised. As a result, there are cases where the support member 210 cannot be etched at an originalprofile position 303 using the resist 302 of this type, and shape processing of the support member 210 is compromised. In this embodiment, the planarity of the support member 210 is maintained, and so the shape processability of the support member 210is favorable.
In this embodiment, as described above, a mediating conductive layer 238 that connects to the second electrode 236 can be provided on the first surface 211A of the support member 210. In this case, the support member 210 can also comprise asecond wiring layer 217 that is disposed on a side of the second surface 211B with respect to the first layer member (insulating layer) 212, a second hole 218 that is formed so as to pass through to the first layer member (insulating layer) 212 at aposition that is opposite the second wiring layer 217 and the mediating conductive layer 238, and a second plug 219 that is embedded in the second hole 218.
In this case as well, the wiring that connects to the second electrode 236 leads to the support member 210 via the second plug 219, and thus the support member 210 is not formed with a step due to the wiring that leads to the second electrode236 (refer to FIG. 1). By preserving the planarity of the support member 210, the resist that is formed on the support member 210 in the production process is formed with high precision, and shape processing of the support member 210 is improved, asdescribed above.
Next, the structure of the capacitor 230 of this embodiment will be described with reference to FIG. 4. With the capacitor 230 shown in FIG. 4, the crystal orientations of the pyroelectric body 232, the first electrode 234, and the secondelectrode 236 are aligned so that the preferential orientation system is the (111) plane system. Because preferential orientation occurs in the (111) plane system, the ratio of orientation in the (111) orientation is controlled at, for example, 90% orgreater relative to other plane systems. In order to increase the pyroelectric constant, the (100) orientation is more preferable than the (111) orientation, but the (111) orientation is used in order to facilitate control of polarization with respectto the direction of the applied electric field. However, the preferential orientation system is not restricted to this orientation system.
The first electrode 234 can comprise, sequentially from the support member 210, an orientation control layer (e.g., Ir) 234A that controls orientation so that the first electrode 234 is preferentially oriented in the (111) plane, a firstreducing gas barrier layer (e.g., IrO.sub.x) 234B, and a preferentially oriented seed layer (e.g., Pt) 234C.
The second electrode 236 can comprise, in sequence from the pyroelectric body 232, an orientation matching layer (e.g., Pt) 236A that matches the crystal orientation of the pyroelectric body 232, a second reducing gas barrier layer (e.g.,IrO.sub.x) 236B, and a resistance reduction layer (e.g., Ir) 236C that reduces the resistance of the junction with the plug 228 that connects to the second electrode 236.
In this embodiment, the first and second electrodes 234 and 236 of the capacitor 230 are provided with multilayer structures so that the infrared detecting element 220 is processed with minimal damage without a reduction in performance despiteits low heat capacity, the crystal lattice level is aligned at the interface, and the pyroelectric body (oxide) 232 is isolated from the reducing gas even if a reducing atmosphere forms around the capacitor 230 during production or during use.
The pyroelectric body 232 is formed by crystal growth of PZT (Pb(Zr, Ti)O.sub.3, generic name: lead zirconate titanate) or PZTN (generic name for material in which Nb is added to PZT), preferentially oriented according to the (111) system, forexample. Using PZTN is preferred in terms of minimizing oxidative damage and lessening the likelihood of reduction, even in a thin film. In order to bring about crystal orientation in the pyroelectric body 232, the crystals of the first electrode 234in the lower layer of the pyroelectric body 232 are oriented from the stage at which the first electrode 234 is formed.
To this end, an Ir layer 234A that functions as an orientation control layer is formed by sputtering on the lower electrode 234. It is desirable to form a titanium aluminum nitride (TiAlN) layer or a titanium nitride (TiN) layer as a bindinglayer under the orientation control layer 234A. This is because binding with the SiO.sub.2 of the SiO.sub.2 support layer (first insulating layer) 212 used as the topmost layer of the support member 210 can thereby be ensured. Although titanium (Ti) isalso suitable as this type of binding layer, titanium (Ti) is undesirable because it is highly dispersible, and thus titanium aluminum nitride (TiAlN) or titanium nitride (TiN) which have high reducing gas barrier properties and little dispersibility arepreferred.
In addition, when the first layer member 212 of the support member 210 is formed from SiO.sub.2, the SiO.sub.2 layer preferably has a surface roughness Ra of less than 30 nm on the side of the SiO.sub.2 layer that is in contact with the firstelectrode 234. When this is done, planarity of the surface of the first layer member 212 on which the capacitor 230 is mounted can be ensured. It is undesirable for the surface on which the orientation control layer 234A is formed to be rough becausethe orientation of the crystals will be disrupted during crystal growth by the unevenness of the rough surface.
Here, the thermal conductivity of the constituent material of the first wiring layer 214 in the region of connection of the first plug 216 furnished to the support member 210 can be lower than the thermal conductivity of the constituent materialof the first electrode 234 in the region of connection of the first plug 216. For example, the first wiring layer 214 can be a multilayer structure whose lower layer is titanium (Ti) and whose upper layer is titanium nitride (TiN).
When this is done, the thermal conductivity of the titanium nitride (TiN) which is the constituent material of the first wiring layer 214 in the region of contact with the first plug 216 provided to the support member 210 can be lower than thethermal conductivity of the iridium (Ir) which is the constituent material of the first electrode 234 in the region of contact with the first plug 216. This is due to the fact that the thermal conductivity of titanium (Ti) is 21.9 (W/mK), which issubstantially less than the thermal conductivity of 147 (W/mK) for iridium (Ir), and the thermal conductivity of the titanium nitride (TiN) is additionally decreased depending on the mixing ratio of nitrogen and titanium.
When the constituent material of the first electrode 234 in the region of contact with the first plug 216 is a binding layer, e.g., titanium aluminum nitride (TiAlN), it is desirable to adjust the blending ratio of nitrogen and titanium so thatthe thermal conductivity of the titanium nitride (TiN) which is the constituent material of the first wiring layer 214 in the region of contact with the first plug 216 is lower than the thermal conductivity of the titanium aluminum nitride (TiAlN).
The IrO.sub.x layer 234B that functions as a reducing gas barrier layer in the first electrode 234 is used in conjunction with the second layer member (e.g., Si.sub.3N.sub.4) 213 of the support member 210 that manifests reducing gas barrierproperties and the etching stop layer (e.g., Al.sub.2O.sub.3) 140 of the support member 210 in order to isolate the pyroelectric body 232 from reducing impediment factors that enter from below the capacitor 230. For example, gas that is released fromthe substrate 100 during firing of the pyroelectric body (ceramic) 232 and other annealing steps and reducing gas that is used in isotropic etching step for the sacrificial layer 150 function reducing impediment factors.
During the firing step for the pyroelectric body 232, evaporated gas is generated in some cases inside the capacitor 230 during high-temperature treatment, but an escape route for this evaporated gas is ensured by the first layer member 212 ofthe support member 210. In other words, in order for the evaporated gas that is generated inside the capacitor 230 to escape, it is desirable to provide gas barrier properties in the second layer member 213 and to not provide gas barrier properties inthe first layer member 212.
In addition, the IrO.sub.x layer 234B itself has little crystallinity, but has favorable compatibility with the Ir layer 234A due to the metal-metal oxide relationship, and the layer thus can have the same preferential orientation system as theIr layer 234A.
The Pt layer 234C that functions as a seed layer in the first electrode 234 has a (111) orientation and serves as a seed layer for preferential orientation of the pyroelectric body 232. In this embodiment, the Pt layer 234C is formed with adouble-layer structure. The first Pt layer serves as a foundation for (111) orientation, and the second Pt layer provides micro-roughness at the surface and functions as a seed layer for preferential orientation of the pyroelectric body 232. Thepyroelectric body 232 is thus made to have (111) orientation in alignment with the seed layer 234C.
The first electrode 234 has a metal oxide layer 2348 between the two metal layers 234A and 234C. For this reason, the heat that is released from the first electrode 234 to the first plug 216 and the first wiring layer 214 can be decreased dueto the metal oxide layer 234B that has lower thermal conductivity than the metal layers 234A and 234C, thereby ensuring thermal isolation of the pyroelectric detecting element 220.
With the second electrode 236, if a film is formed using a sputtering method, then the interface will be physically rough, and there is the danger that characteristics will deteriorate as a result of the generation of trap sites. Consequently,reconstruction of crystal-level lattice matching is carried out in order to produce a continuous crystal orientation in the first electrode 234, the pyroelectric body 232, and the second electrode 236.
Although the Pt layer 236A of the second electrode 236 is formed by sputtering, the crystal orientation of the interface immediately after sputtering is not continuous. Thus, the Pt layer 236A is recrystallized by carrying out a subsequentannealing treatment. In other words, the Pt layer 236A functions as an orientation matching layer, and the crystal orientation is made to match that of the pyroelectric body 232.
The IrO.sub.x layer 236B in the second electrode 236 functions as a barrier to reducing impediment factors that enter from above the capacitor 230. In addition, the Ir layer 236C in the second electrode 236 has a higher resistance than theIrO.sub.x layer 236B, and so it is used in order to lower the resistance with respect to the plug 228. The Ir layer 236C has favorable compatibility with the IrO.sub.x layer 236B due to the metal oxide-metal relationship and has the same preferentialorientation system as the IrO.sub.x layer 236B.
Thus, in this embodiment, the first and second electrodes 234, 236 are disposed in multiple layers of Pt, IrOx, and Ir in the stated order relative to the pyroelectric body 232, the forming materials being arranged symmetrically about thepyroelectric body 232.
However, the thicknesses of the respective layers of the multilayer structures that form the first and second electrodes 234, 236 are asymmetrical about the pyroelectric body 232.
FIG. 5 shows a configuration example for an infrared camera 400A which is used as an example of an electronic instrument that comprises the pyroelectric detector or pyroelectric detection device of this embodiment. This infrared camera 400Acomprises an optical system 400, a sensor device (pyroelectric detection device) 410, an image processing part 420, a processing part 430, a storage part 440, an operating part 450, and a display part 460.
The optical system 400 comprises, for example, one or a plurality of lenses or a drive part that drives these lenses. An image of an object is captured by the sensor device 410, and focal adjustment is carried out as necessary.
The sensor device 410 has a configuration in which pyroelectric detectors 200 of the embodiments described above are arranged two-dimensionally, and a plurality of lines (scan lines or word lines) and a plurality of columns (data lines) areprovided. The sensor device 410 can also comprise a row selection circuit (row driver), a read circuit for reading data from the detectors via the columns, an A/D converter, and the like, in addition to the detectors that are arranged two-dimensionally. Because data is sequentially read from the detectors that are arranged two-dimensionally, a captured image of the object can be processed.
Based on the digital image data (pixel data) from the sensor device 410, the image processing part 420 carries out various image processing operations such as image correction processing.
The processing part 430 carries out control of the respective elements of the infrared camera 400A and overall control of the infrared camera 400A. This processing part 430 is realized, for example, in a CPU or the like. The storage part 440stores various types of information, and, for example, functions as a work space for the processing part 430 or the image processing part 420. The operating part 450 is used as an interface for a user to operate the infrared camera 400A and can berealized, for example, in the form of various buttons, a GUI (graphical user interface) screen, or the like. The display part 460 displays the GUI screen, and images that have been captured by the sensor device 410 and the like, the display part 460being realized in the form of various types of displays, such as a liquid crystal display or organic EL display.
In this manner, by using the pyroelectric detectors of each of single cells as sensors, such as infrared sensors, and, moreover, by disposing the pyroelectric type photodetectors of each of the single cells two-dimensionally along two axialdirections, e.g., in two orthogonal axial directions, a sensor device 410 can be configured. Therefore, thermal (light) distribution images can be provided. Using this sensor device 410, an electronic instrument, such as a thermographic device, anon-board automotive night-vision camera, a surveillance camera, or the like, can be configured.
As shall be apparent, using the pyroelectric detector of one cell or a plurality of cells as a sensor, it is possible to configure various types of electronic instruments, such as analytical instruments (measurement instruments) for analyzing(measuring) physical data related to an object, security instruments for detecting smoke or heat, and FA (factory automation) instruments that are installed in factories and the like.
FIG. 6 shows a configuration example of an on-board assistance device 600 that is an example of an electronic instrument comprising the pyroelectric detector or pyroelectric detection device of this embodiment. The on-board assistance device600 has a configuration comprising a processing unit 610 having a CPU for controlling the on-board assistance device 600, an infrared camera 620 that allows detection of infrared light in a prescribed imaging region outside the automobile, a yaw ratesensor 630 that detects the automobile yaw rate, a speed sensor 640 that detects the travel speed of the automobile, a brake sensor 650 that detects operation of the brake by the driver, a speaker 660, and a display device 670.
The processing unit 610 of the on-board assistance device 600 detects an object such as a pedestrian or a body that is present in advance of the travel direction of the automobile from infrared images of the periphery of the automobile obtainedby imaging using the infrared camera 620, and detection signals related to the state of travel of the automobile that are detected by the respective sensors 630 to 650. When it is determined that contact between the automobile and a detected object mayoccur, a warning is output by the speaker 660 or the display device 670.
For example, as shown in FIG. 7, the infrared camera 620 is disposed near the middle of the vehicle width direction along the front of the automobile. The display device 670 is configured by providing a heads-up display (HUD) 671 that displaysvarious data in a position in the front window that does not obstruct the frontward field of view of the operator.
FIG. 8 shows an example of a security instrument 700 which is used as an example of an electronic instrument that comprises the pyroelectric detector or pyroelectric detection device of this embodiment.
The security instrument 700 comprises an infrared camera 710 for capturing images of at least an area to be monitored, a human sensor 720 for detecting intruders into the monitored area, a detection processing part 730 for acting to detectmoving bodies that enter into the monitored area by processing image data that is output from the infrared camera 710, a human sensor detection processing part 740 for carrying out detection processing for the human sensor 720, an image compression part750 for compressing image data that has been output from the infrared camera 710 into a prescribed format, a communication processing part 760 for transmitting compressed image data or intruder detection data and receives various types of settinginformation for the security instrument 700 from external devices, and a control part 770 for using a CPU to carry out parameter setting, processing command transmission, and response processing with respect to various processing parts of the securityinstrument 700.
The motion detection processing part 730 has a buffer memory that is not shown in the drawings, a block data smoothing part whereby the output of the buffer memory is input, and a state modification detection part whereby the output of the blockdata smoothing part is input. The state modification detection part of the movement detection processing part 730 detects a change in state using the fact that the same image data will be present in different frames taken in movie mode if the monitoredarea is under static conditions, whereas a difference in image data between frames will arise when a change of state occurs (entry of a moving body).
FIG. 9 is a side view of a security instrument 700 that is installed, e.g., under a roof overhang, the imaging area A1 of the infrared camera 710 that is contained in the security instrument 700, and the detection area A2 of a human sensor 720.
FIGS. 10 and 11 show an example of the configuration of a gaming device 800 including a controller 820 for utilizing the sensor device 410 described above, which is used as an example of an electronic instrument including the pyroelectricdetector or pyroelectric detection device of this embodiment.
As shown in FIG. 10, the controller 820 that is used in the gaming device 800 of FIG. 11 has a configuration that comprises an image data computation unit 830, an operating switch 840, an acceleration sensor 850, a connector 860, a processor870, and a wireless module 880.
The imaging data computation unit 830 has an image capture unit 831 and an image processing circuit 835 for processing the image data that has been captured by the image capture unit 831. The image capture unit 831 includes a sensor device 832(sensor device 410 of FIG. 5), there being disposed in front thereof an infrared filter 833 (that admits only infrared light) and an optical system (lens) 834. The image processing circuit 835 processes the infrared image data obtained from the imagecapture unit 831, detects high-brightness portions, detects the centers of gravity and the surface areas thereof, and then outputs these data.
The processor 870 outputs, as a series of control data, operational data obtained from the operating switch 840 and acceleration data obtained from the acceleration sensor 850, as well as high-brightness data. The wireless module 880 modulatesa carrier signal of a prescribed frequency with the control data and outputs a signal from the antenna 890 as a radio signal.
The data that has been input through the connector 860 that is provided on the controller 820 is processed by the processor 870 in the same manner as the data described above and is output via the wireless module 880 and the antenna 890.
As shown in FIG. 11, the gaming device 800 has a controller 820, a gaming device main unit 810, a display 811, and LED modules 812A and 812B. The player 801 uses one hand to grasp the controller 820 to play the game. When the image captureunit 831 of the control 820 is facing the screen 813 of the display 811, infrared light that is output from the LED modules 812A and 812B that are disposed near the display 811 is detected by the image capture unit 831, and the controller 820 acquiressurface area and position information of the two LED modules 812A and 812B as high-brightness point information. Data concerning the positions and sizes of the bright points is transmitted wirelessly from the controller 820 to the gaming device mainunit 810 and is received by the gaming device main unit 810. When the player 801 moves the controller 820, the position and size data of the bright points change, and this change is used in order to allow the gaming device main unit 810 to acquireoperational signals corresponding to movement of the controller 820, thereby allowing gaming to progress.
FIG. 12 shows an example of the configuration of a body temperature measurement device 900 which is used as an example of the electronic instrument of this embodiment that contains the pyroelectric detector or pyroelectric detection device.
As shown in FIG. 12, the body temperature measurement device 900 has a configuration that comprises an infrared camera 910, a body temperature analysis device 920, an information notification device 930, and a cable 940. The infrared camera 910has a configuration that comprises an optical system such as a lens (not shown), and the aforementioned sensor device 410.
The infrared camera 910 images a predetermined target region, and image data related to the subject 901 whose image has been captured is transmitted to the body temperature analysis device 920 via the cable 940. The body temperature analysisdevice 920 (not shown) comprises an image reading processing unit that reads the heat distribution image from the infrared camera 910, a body temperature analysis unit that generates a body temperature analysis table based on an image analysis settingstable together with data from the image reading processing unit and transmits body temperature transmission data based on the body temperature analysis table to the information notification device 930. This body temperature transmission data may alsoinclude predetermined data for when the body temperature is abnormal. When it is determined that a plurality of subjects 901 are in the image capture region, the body temperature transmission data also includes information concerning the number ofsubjects 901 and the number of persons having an abnormal body temperature.
FIG. 13 shows an example of the configuration of a specified substance search device 1000 that combines a terahertz illumination unit along with a terahertz light sensor device in the form of a sensor device having a terahertz range for theabsorption wavelengths of the light-absorbing material of the pyroelectric detector of the sensor device 410 described above. This device is used as an example of an electronic device of this embodiment that includes a pyroelectric detector orpyroelectric detection device.
The specified substance searching device 1000 has a configuration that comprises a control unit 1010, an illumination unit 1020, an optical filter 1030, an image capture unit 1040, and a display part 1050. The image capture unit 1040 has aconfiguration that comprises an optical system such as a lens, and a sensor device having a terahertz absorption wavelength range for the light-absorbing material of the aforementioned pyroelectric detector (neither of which being shown in the drawing).
The control unit 1010 includes a system controller, where the system controller controls the entire device and controls the image processing unit and the light source drive part included in the control unit. The illumination unit 1020 includesan optical system and a laser device that emits terahertz light (electromagnetic radiation in the wavelength range of 100 to 1000 .mu.m), thereby illuminating the person 1060 who is the subject of inspection with terahertz light. The reflected terahertzlight from the person 1060 is received by the image capture unit 1040 via the optical filter 1030 that allows only light in the spectrum of the specified substance 1070 that is the target of investigation to pass. The image signal that is generated bythe image capture unit 1040 is subjected to prescribed image processing by the image processing unit of the control unit 1010, and the image signal is output to the image display part 1050. The presence of a specified substance 1070 can be determineddepending on the intensity of the received light signals which differ depending on whether the specified substance 1070 is present in the clothing or the like of the human 1060.
A number of embodiments of electronic instruments were described above, but the electronic instruments of the embodiments described above are not restricted by the configurations that have been presented, and various modifications may beimplemented that involve elimination of some of the constituent elements (e.g., optical system, operating part, display part) and addition of other constituent elements.
An example of the configuration of a sensor device 410 of FIG. 5 is shown in FIG. 14A. This sensor device comprises a sensor array 500, a row selection circuit (row driver) 510, and a read circuit 520. The device may also comprise an A/Dconversion part 530 and a control circuit 550. The row selection circuit (row driver) 510 and the read circuit 520 are referred to as the "driver circuit." As shown in FIG. 5, this sensor device can be used in an infrared camera 400A that is used in anavigation device.
In the sensor array 500, a plurality of sensor cells are arranged (disposed) along two axes as shown, for example, in FIG. 2. A plurality of rows (word lines, scan lines) and a plurality of columns (data lines) are also provided. The number ofeither the rows or columns may also be one. For example, when the number of rows is one, a plurality of sensor cells are arranged along the row direction (horizontal direction) in FIG. 14A. On the other hand, when the number of columns is one, aplurality of sensor cells is arranged in the column direction (vertical direction).
As shown in FIG. 14B, each of the sensor cells of the sensor array 500 is disposed (formed) at a location corresponding to the intersection position of a row and a column. With the sensor cell shown in FIG. 14B, the cells are disposed at alocation corresponding to the intersection of the row WL1 and the column DL1. The other sensor cells are similar.
The row selection circuit 510 is connected to one or a plurality of rows and carries out the selection operation for each row. For example, taking the sensor array 500 (focal plan array) of a QVGA (320.times.240 pixels) device shown in FIG. 14Bas an example, operation is carried out by the sequential selection (scanning) of rows WL0, WL1, WL2, . . . WL239. Specifically, signals for selecting these rows (word selection signals) are output to the sensor array 500.
The read circuit 520 is connected to one or a plurality of columns. Read operations are thereby carried out on respective columns. Taking the QVGA sensor array 500 as an example, a reading operation is carried out on the detection signals(detected current, detected charge) from the columns DL0, DL1, DL2, . . . DL319.
The A/D conversion part 530 carries out processing whereby the detected voltage (measured voltage, attained voltage) acquired by the read circuit 520 is subjected to A/D conversion to produce digital data. Digital data DOUT is thus output afterA/D conversion. Specifically, respective A/D converters corresponding to each column of the plurality of columns are provided in the A/D conversion part 530. The respective A/D converters carry out A/D conversion on the detected voltages that have beenacquired by the read circuit 520 for the corresponding columns. A single A/D converter may also be provided for a plurality of columns, and the detected voltages for the plurality of columns may be subjected to time-division A/D conversion using thissingle A/D converter.
The control circuit 550 (timing generation circuit) generates various types of control signals which are output to the row selection circuit 510, the read circuit 520, and the AD conversion part 530. For example, a charge or discharge (reset)control signal is generated and output. Alternatively, a signal that controls the timing for each of the circuits is generated and output.
While only selected embodiments have been described, it will be readily apparent to those skilled in the art from the novel matters and effects of the present invention that numerous modifications may be made herein without substantiallydeparting from the scope of the invention. Consequently, all modifications such as the above may be understood to fall within the scope of the invention. Terms disclosed together with different equivalent or broader terms in at least one instance inthe specification or drawings, for example, may be replaced by these different terms at any place in the specification or drawings.
The present invention can be widely implemented in various types of pyroelectric detectors (e.g., thermocouple elements (thermopiles), pyroelectric type elements, and the like). The wavelength of the light to be detected does not matter. Inaddition, pyroelectric detectors or pyroelectric detection devices, or electronic instruments having these, can be implemented, for example, in flow sensors and the like for detecting the flow rate of a fluid under conditions in which there isequilibrium between supplied heat and heat lost into the fluid. The pyroelectric detector or pyroelectric detection device of the present invention may be furnished in place of the thermocouple or the like of the flow sensor, and the subject ofdetection can thus be one other than light.
In understanding the scope of the present invention, the term "comprising" and its derivatives, as used herein, are intended to be open ended terms that specify the presence of the stated features, elements, components, groups, integers, and/orsteps, but do not exclude the presence of other unstated features, elements, components, groups, integers and/or steps. The foregoing also applies to words having similar meanings such as the terms, "including", "having" and their derivatives. Also,the terms "part," "section," "portion," "member" or "element" when used in the singular can have the dual meaning of a single part or a plurality of parts. Also as used herein to describe the above embodiments, the following directional terms "top","bottom", "upper", "lower", "forward", "rearward", "above", "downward", "vertical", "horizontal", "below" and "transverse" as well as any other similar directional terms refer to those directions of the pyroelectric detector when the pyroelectricdetector is oriented as shown in FIG. 1. Finally, terms of degree such as "substantially", "about" and "approximately" as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. Forexample, these terms can be construed as including a deviation of at least .+-.5% of the modified term if this deviation would not negate the meaning of the word it modifies.
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