JP2013096788A - Pyroelectric type photodetector, pyroelectric type photodetecting apparatus and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently transfer heat generated in a plurality of light absorption regions to a pyroelectric body of a plurality of pyroelectric capacitors to increase the detection output of the pyroelectric detector.
A pyroelectric detector includes a base body 20, a support member 30, and a plurality of pyroelectric capacitors Capa1 to Capa4 including a pyroelectric body. The support member 30 includes a first surface 30 </ b> A and a second surface 30 </ b> B that faces the first surface, and a cavity 100 is formed between the second surface and the base body 20. The plurality of pyroelectric capacitors Capa <b> 1 to Capa <b> 4 are supported on the support member 30. Each of the plurality of pyroelectric capacitors Capa1 to Capa4 has a corresponding one light absorption region AR1 to AR4. The positions of the projection points obtained by projecting the centroids G1a to G1d of the light absorption regions AR1 to AR4 onto the two-dimensional surface in plan view are the respective pyroelectric capacitors Capa1 to Capa1 corresponding to the light absorption regions AR1 to AR4. It exists in the area | region J1-J4 which projected the outline of the pyroelectric body 12 of Capa4 on the two-dimensional surface.
[Selection] Figure 1

Description

  The present invention relates to a pyroelectric detector, a pyroelectric photodetector, an electronic device, and the like.

  A thermal detector is known as an optical sensor. The thermal detector absorbs light emitted from an object by a light absorption layer, converts the light into heat, and measures a change in temperature with a heat detection element. Examples of the thermal detector include a thermopile that directly detects a temperature rise due to light absorption as a thermoelectromotive force, a pyroelectric element that detects a change in electrical polarization, and a bolometer that detects a temperature rise as a resistance change. . Thermal detectors have a wide wavelength band that can be measured.

  In a pyroelectric detector that is an example of a thermal detector, infrared rays that are an example of light emitted from an object are absorbed by, for example, an infrared absorption layer and converted into heat. By giving the heat to the pyroelectric material, the amount of spontaneous polarization of the pyroelectric material changes. The amount of infrared rays is detected by the pyroelectric current based on the amount of change.

  In recent years, attempts have been made to manufacture smaller thermal detectors using semiconductor manufacturing technology (MEMS technology or the like). Patent Document 1 describes a monolithic thermal sensor having a pyroelectric layer. In this pyroelectric detector, a pyroelectric detector is formed on an integrated circuit substrate using semiconductor manufacturing technology. FIG. 6 of Patent Document 1 discloses a configuration in which two pyroelectric elements configured by sandwiching a pyroelectric material thin film made of a dielectric between electrodes are connected by a common plate.

  In addition, FIG. 2 of Patent Document 2 describes an infrared sensor provided with a pyroelectric film. In the sensor having the pyroelectric film, the lower electrode, the pyroelectric film, and the upper electrode are formed in this order on the insulating film supported by the substrate, and the light absorption film is formed on the upper electrode and the pyroelectric film. The

JP-A-8-271344 Japanese Patent Laid-Open No. 5-187717

  In recent years, it has been demanded to increase the detection output of a pyroelectric detector. The output voltage based on the amount of spontaneous polarization in the pyroelectric capacitor generated by heat caused by incident light depends on the area of the light receiving region, the area of the pyroelectric capacitor, the resistance of the pyroelectric capacitor, and the like.

  According to at least one aspect of the present invention, the heat generated in the plurality of light absorption regions is efficiently transferred to the pyroelectric bodies of the plurality of pyroelectric capacitors to increase the detection output of the pyroelectric detector. be able to.

(1) A pyroelectric detector according to an aspect of the present invention is
A substrate;
A support member including a first surface and a second surface facing the first surface, the support member being disposed between the second surface and the base via a cavity portion;
A plurality of pyroelectric capacitors each including a pyroelectric material supported by the support member;
A light absorbing layer provided in contact with each of the plurality of pyroelectric capacitors;
Have
The plurality of pyroelectric capacitors are electrically connected;
The light absorption layer comprises a plurality of light absorption regions corresponding to each of the plurality of pyroelectric capacitors,
In plan view from the thickness direction of the substrate, the center of gravity of each of the plurality of light absorption regions exists at a position where each of the plurality of light absorption regions overlaps the pyroelectric body of each one of the pyroelectric capacitors corresponding thereto. The present invention relates to a pyroelectric detector.

  In one embodiment of the present invention, light absorbed in each one light absorption region is transmitted as heat to the pyroelectric body of each one pyroelectric capacitor. In the pyroelectric body, the amount of spontaneous polarization changes due to the pyroelectric effect (pyro electronic effect) caused by heat based on light, and the amount of light (heat amount) is detected by obtaining the amount of change. At this time, the plurality of pyroelectric capacitors mounted on one support member constitute a common pixel (one pixel), and light incident on each one light absorption region at the same time is each one pyroelectric capacitor. Must be detected at the same time. In one embodiment of the present invention, heat absorbed by each one light absorption region is transmitted to the pyroelectric body of each one pyroelectric capacitor, and heat transfer characteristics can be made uniform. Therefore, for example, the peaks (crests) of the generated charges on the time axis are aligned, and simultaneous detection is possible with a plurality of pyroelectric capacitors, and the detection output of the pyroelectric detector can be increased. In other words, the thermal time constant of the pyroelectric detector is reduced. For example, when outputting a two-dimensional image heat distribution based on the output of a plurality of pyroelectric detectors, the image is displayed at a high frame rate. can do.

  Here, when one light absorbing member is arranged in a region covering a plurality of pyroelectric capacitors, the one light absorbing member is divided into one light absorbing region corresponding to each of the plurality of pyroelectric capacitors. . In addition, a plurality of light absorbing members may be provided in regions covering the plurality of pyroelectric capacitors, and in this case, one light absorbing member becomes one light absorbing region.

  Note that a plurality (n, n is an integer of 2 or more) pyroelectric capacitors can be connected in series in a direction in which the polarization directions are aligned on the support member. For example, when n pyroelectric capacitors having the same electrode area are connected in series with a pyroelectric capacitor arranged as a single unit, the combined resistance of the n pyroelectric capacitors is increased by a factor of n. Due to this effect, the output voltage can theoretically be n times the output voltage of the pyroelectric heat detection element composed of one pyroelectric element. However, one embodiment of the present invention is not necessarily limited to connecting a plurality of pyroelectric capacitors in series on the support member, and signals from the plurality of pyroelectric capacitors may be individually taken out.

  (2) In the pyroelectric detector according to one aspect of the present invention, the center of gravity of each of the plurality of light absorption regions in the plan view is a single focus corresponding to each of the plurality of light absorption regions. The electric capacitor may have an overlap with the center of gravity of the pyroelectric body.

  In this way, heat generated at various locations in one light absorption region is evenly collected near the center of gravity of one light absorption region. The heat is efficiently transferred to the center of gravity of the pyroelectric body that overlaps with the center of gravity of one light absorption region in plan view. Therefore, in each pyroelectric capacitor, electric charges can be generated with little variation by thermal / electrical conversion.

  (3) In the pyroelectric detector according to one aspect of the present invention, the pyroelectric body of each of the plurality of pyroelectric capacitors has a contour of n (n is an integer of 3 or more) square, Each contour of the plurality of light absorption regions including one contour line to nth contour line and corresponding to each of the plurality of pyroelectric capacitors is an m-th contour line (1 ≦ m ≦ n) of the pyroelectric body. The distance dm between the m-th contour line and the m-th counter contour line may be constant regardless of the value of m.

  In this embodiment, one light absorption region and one pyroelectric body are similar n-gons. Therefore, the distance from the first centroid to the m-th counter contour is the same regardless of the value of m in one light absorption region, and the distance from the second centroid to the m-th contour is the value of m even in one pyroelectric body. Will be equal regardless of Thereby, the heat generated in one light absorption region can be evenly collected in the pyroelectric body of one pyroelectric capacitor.

  (4) In the pyroelectric detector according to one aspect of the present invention, the outline of the pyroelectric body of each of the plurality of pyroelectric capacitors may be a circle or an ellipse.

  From the viewpoint of stress relaxation in the support member, the outline of the pyroelectric body of the pyroelectric capacitor is superior to a circle or an ellipse. The outline of the light absorption region may be a circle, an ellipse, or a rectangle, but the circle or ellipse is superior from the viewpoint of stress relaxation.

  (5) In the pyroelectric detector according to one aspect of the present invention, each of the plurality of pyroelectric capacitors includes a first electrode and a second electrode sandwiching the pyroelectric body, and the first electrode is The planar capacitor may be supported by a support member, and the area of the first electrode in the plan view may be larger than the area of the second electrode.

  With the so-called planar structure, wiring to the first electrode mounted on the support member can be formed on the support member. In addition, a light absorption region can be formed on the enlarged first electrode, the light absorption area is enlarged, and the first electrode exhibits the effect of a heat collection path and is generated at the periphery of the light absorption region. The collected heat can be collected on the center side where the pyroelectric material exists.

  (6) In one aspect of the present invention, the pyroelectric body of each of the plurality of pyroelectric capacitors can have a side surface covered with an electrically insulating metal compound layer. The pyroelectric material is an oxide, and oxygen deficiency occurs when reduced. The metal compound layer has a reducing gas barrier property and can suppress the reduction of the pyroelectric material. Thus, oxygen deficiency of the pyroelectric material can be suppressed, and thus it is possible to downsize the pyroelectric capacitor and mount a plurality of pyroelectric capacitors on one support member.

  (7) In one aspect of the present invention, the light absorption layer can be formed of a plurality of light absorption layers that are divided and formed corresponding to each of the plurality of pyroelectric capacitors.

  Since the light absorption layer is individualized, the heat of each absorption layer escapes from the surroundings, and thus the reset time of each pyroelectric capacitor can be shortened. In addition, in the case where one light absorption layer is divided into regions to form individual light absorption regions, the area of the light absorption layer can be increased compared to the case where the light absorption layer is individualized. Therefore, there is an advantage that the manufacturing process can be omitted.

  (8) In one aspect of the present invention, the support member may have a through hole in a region between two adjacent pyroelectric capacitors among the plurality of pyroelectric capacitors.

  Here, when the support member, the plurality of pyroelectric capacitors, and the like are formed on the substrate, the sacrificial layer is embedded in the cavity. The sacrificial layer is removed by isotropic etching using an etchant after forming a support member, a plurality of pyroelectric capacitors, and the like on the substrate. During the etching, the through-hole is used as an etchant supply port. As a result, the etchant can easily reach the sacrificial layer below the support member, and the sacrificial layer can be easily removed by isotropic etching.

  (9) Another aspect of the present invention defines a pyroelectric detection device that is two-dimensionally arranged along two linear directions intersecting the above-described pyroelectric detector.

  As a result, a plurality of pyroelectric detectors (pyroelectric detectors) are two-dimensionally arranged (for example, arranged in an array along each of two orthogonal axes). An apparatus (pyroelectric optical array sensor) is realized.

  (10) Still another aspect of the present invention defines an electronic apparatus having the above-described pyroelectric detector or pyroelectric detector.

  Any of the above pyroelectric detectors has high light detection sensitivity. Therefore, the performance of an electronic device equipped with this pyroelectric detector is enhanced. Examples of the electronic device include an infrared sensor device, a thermography device, a vehicle-mounted night camera, a monitoring camera, and the like.

1A and 1B are a schematic plan view and a two-dimensional projection plane of a pyroelectric detector having four capacitors according to the first embodiment of the present invention. 2A shows the area and element area of the light absorption region of the first embodiment, FIG. 2B shows the area and element area of the light absorption region of the first comparative example, and FIG. It is a figure which shows the area and element area of the light absorption area | region of the comparative example 2. It is a figure which shows the bias application state of the capacitor connected in series of 1st Embodiment. It is a schematic plan view of a pyroelectric detector having four capacitors in series according to the first embodiment. It is a schematic sectional drawing of the pyroelectric photodetector which has three capacitors in series which concerns on 1st Embodiment. 6A and 6B are diagrams showing examples of connection wiring of two pyroelectric capacitors. It is sectional drawing which shows embodiment which applied this invention to the pyroelectric detector which has a stack type pyroelectric capacitor. It is a figure for demonstrating the relationship between the outline of a some light absorption area | region, and the outline of each pyroelectric body of a some pyroelectric capacitor. FIG. 9A is a diagram illustrating a layout of a light absorption region that causes non-uniform heat transfer and a pyroelectric body of a pyroelectric capacitor, and FIG. 9B is a diagram illustrating non-uniform heat transfer characteristics. It is a top view of the supporting member in which the through-hole was formed between several pyroelectric capacitors. It is a circuit diagram which shows an example of the circuit structure of the pyroelectric detection apparatus (pyroelectric detection array) which concerns on 2nd Embodiment of this invention. It is a block diagram of the infrared camera (electronic device) which concerns on 3rd Embodiment of this invention containing a pyroelectric detector or a pyroelectric detector. It is a figure which shows the driving assistance apparatus (electronic device) which concerns on 3rd Embodiment of this invention containing an infrared camera. It is a figure which shows the vehicle which concerns on 3rd Embodiment of this invention which mounted the infrared camera shown in the front part. It is a figure which shows the security apparatus (electronic device) which concerns on 3rd Embodiment of this invention containing an infrared camera. It is a figure which shows the detection area of the infrared camera of a security apparatus, and a human sensitive sensor. It is a figure which shows the controller used for the game device which concerns on 3rd Embodiment of this invention including a sensor device. It is a figure which shows the game device containing a controller. It is a figure which shows the body temperature measuring apparatus (electronic device) which concerns on 3rd Embodiment of this invention containing an infrared camera. It is a figure which shows the example which comprised the specific substance detection apparatus (electronic device) combining the terahertz irradiation unit using a sensor device as a terahertz sensor device. FIGS. 21A and 21B are diagrams illustrating a configuration example of a pyroelectric detection device in which pyroelectric detectors are two-dimensionally arranged.

  Hereinafter, preferred embodiments of the present invention will be described in detail. The present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in the present embodiment are indispensable as means for solving the present invention. Not always.

1. 1. First embodiment 1.1. Arrangement of a plurality of light absorption regions and a plurality of capacitors FIGS. 1A and 1B are conceptual diagrams of a pyroelectric detector according to the first embodiment of the present invention. As shown in FIG. 1A, a plurality of, for example, four pyroelectric capacitors (also referred to as capacitors) Capa 1 to Capa 4 are mounted on a support member (membrane) 30. Each of the capacitors Capa1 to Capa4 on the support member 30 has a pyroelectric body between two electrodes. In addition, each of the capacitors Capa1 to Capa4 on the support member 30 is disposed inside the light absorption layer 50 having a plurality of light absorption regions AR1 to AR4 having substantially the same area, for example. The light absorption layer 50 may be divided into a plurality of light absorption regions AR1 to AR4 or may be integrally formed.

  FIG. 1B shows the first gravity centers G1a to G1d obtained by projecting the respective gravity centers of the light absorption regions AR1 to AR4 onto a two-dimensional plane in plan view, and the outlines of pyroelectric bodies of the pyroelectric capacitors Capa1 to Capa4. Regions J1 to J4 projected on the two-dimensional surface and second centroids G2a to G2d obtained by projecting the centroids of the pyroelectric bodies of the pyroelectric capacitors Capa1 to Capa4 onto the two-dimensional surface are shown.

  As is clear from FIG. 1B, each of the first centroids G1a to G1d exists inside each of the regions J1 to J4 obtained by projecting the outline of the pyroelectric body onto the two-dimensional surface.

  Here, the light absorbed in each of the light absorption regions AR1 to AR4 is transmitted as heat to each pyroelectric body of the pyroelectric capacitors Capa1 to Capa4. In the pyroelectric body, the amount of spontaneous polarization changes due to the pyroelectric effect (pyro electronic effect) caused by heat based on light, and the amount of light (heat amount) is detected by obtaining the amount of change. At this time, the plurality of pyroelectric capacitors Capa1 to Capa4 mounted on one support member 30 constitute a common pixel (one pixel), and the light incident on each of the light absorption regions AR1 to AR4 at the same time, It must be detected simultaneously in each of pyroelectric capacitors Capa1-Capa4. In the present embodiment, heat absorbed in each of the light absorption regions AR1 to AR4 is transmitted to each pyroelectric body of the pyroelectric capacitors Capa1 to Capa4, so that heat transfer characteristics can be made uniform. Therefore, for example, the peaks (crests) of the generated charges on the time axis are aligned, and simultaneous detection is possible with each of the plurality of pyroelectric capacitors Capa1 to Capa4.

  Particularly in FIG. 1B, each of the first centroids G1a to G1d and each of the second centroids G2a to G2d have an overlap. In this way, the heat generated at various locations in the light absorption regions AR1 to AR4 is evenly collected in the vicinity of each of the first centroids G1a to G1d. The heat is efficiently transferred to the pyroelectric body having each of the second centroid second centroids G2a to G2d that overlaps each of the first centroids G1a to G1d on the two-dimensional projection plane. Therefore, in each of the pyroelectric capacitors Capa1 to Capa4, electric charges can be generated with little variation by thermal / electrical conversion. However, each of the first centroids G1a to G1d and each of the second centroids G2a to G2d are not limited to overlap. At least one of the first centroids G1a to G1d only needs to exist inside each of the regions J1 to J4 obtained by projecting the outline of the pyroelectric body onto the two-dimensional surface.

  In addition, when one light absorption member is arrange | positioned in the area | region which covers several pyroelectric capacitors Capa1-Capa4, this one light absorption member is divided | segmented and one corresponding to each of several pyroelectric capacitors Capa1-Capa4 It becomes light absorption area AR1-AR4. In addition, a plurality of light absorbing members may be provided in regions covering the plurality of pyroelectric capacitors, and in this case, one light absorbing member becomes one light absorbing region.

1.2. In the example of FIG. 1, the first capacitor Capa <b> 1 to the fourth capacitor Capa <b> 4 are connected in series on the support member 30. However, the first capacitor Capa <b> 1 to the fourth capacitor Capa <b> 4 are not necessarily connected in series on the support member 30, and may be connected in series outside the support member 30, for example.

  In FIG. 1A, plus and minus indicate the polarization polarities of the capacitors Capa1 to Capa4. In this example, the capacitance values of the capacitors Capa1 to Capa4 are the same, but are not limited thereto. The positive electrode of the first capacitor Capa1 is connected to the first external terminal TA1, and the first external terminal TA1 is positive. The negative electrode of the fourth capacitor Capa4 is connected to the second external terminal TA2, and the second external terminal TA2 has a negative polarity.

  Here, FIG. 2A shows a schematic plan view of this embodiment, FIG. 2B shows a schematic plan view of Comparative Example 1, and FIG. 2C shows a schematic plan view of Comparative Example 2. It is assumed that the light receiving portion areas (areas of the light absorption regions) Aa shown in FIGS.

  First, this embodiment shown in FIG. 2A is compared with Comparative Example 1 shown in FIG. Each of the capacitors Capa1 to Capa4 shown in FIG. 2A and the single Capa shown in FIG. 2B have the same element area Ac and capacitance C.

In both FIG. 2A and FIG. 2B, the output voltage from the capacitor obtained by converting the heat of the irradiation light into the charge Q is the combined resistance of the capacitor Rp (in the case of FIG. 2A). Resistance)
Vs = Q × Rp (1)
It becomes. That is, the output voltage Vs of the pyroelectric detector varies according to the product of the polarization charge Q of the capacitor and the resistance value Rp of the capacitor. Further, since the charge Q is proportional to the light receiving area Aa and the element area Ac,
Vs∝Aa ・ Ac ・ Rp (2)
Is established.

  In FIG. 2A, since the capacitors Capa1 to Capa4 are connected in series, the element area Ac of the capacitors Capa1 to Capa4 is electrically the element area Ac of one capacitor Capa as shown in FIG. Is equivalent to Further, as described above, the light receiving portion area (light absorption region area) Aa in FIG. 2A is equal to the light receiving portion area (light absorption region area) Aa in FIG.

Therefore, next, the element resistance of the capacitor will be considered with respect to Rp. In FIG. 2B, from the relationship between the element resistance Rp and the capacitance,
Rp = 1 / C (3)
Is established.

On the other hand, in FIG. 2A, when the capacitance values of the capacitors Capa1 to Capa4 are C, the combined capacitance value of the combined capacitors Capa connected in series is C / 4. If the combined element resistance is Rpx,
Rpx = 4 / C = 4 × Rp (4)
Is established.

  Therefore, referring to equation (1), the output voltage Vs obtained in this embodiment shown in FIG. 2A is four times the output voltage obtained in Comparative Example 1 shown in FIG. I understand that. That is, by connecting n capacitors in series, the combined capacitance (capacitance of the electrical capacitor) determined by the electrical electrode surface is 1 / n compared to the case of the single capacitor of Comparative Example 1, thereby It can be seen that the combined resistance becomes n times, and as a result, the output voltage Vs becomes n times.

  Next, this embodiment shown in FIG. 2A is compared with Comparative Example 2 shown in FIG. Assume that the total element area (4 × Ac) of the capacitors Capa1 to Capa4 shown in FIG. 2 (A) is equal to the element area (4 × Ac) of a single Capa shown in FIG. 2 (C).

  The element area of Comparative Example 2 is 4 × Ac compared to the four series-connected electric element areas Ac shown in FIG. On the other hand, in FIG. 2A, when the capacitance values of the capacitors Capa1 to Capa4 are C, the combined capacitance value of the combined capacitors Capa connected in series is C / 4, and the resistance value is 4 according to the equation (4). X Rp. On the other hand, the capacitance value of the single capacitor Capa in FIG. 2C is 4 × C, and the resistance value of the single capacitor Capa in FIG. 2C is Rp / 4. For this reason, in FIG. 2C, the element area (4 × Ac) is four times, but the resistance value (Rp / 4) is ¼, which is offset by the element area and the resistance value. Therefore, the output voltage Vs in FIG. 2C is equivalent to that in FIG. 2B, and is ¼ of the output voltage Vs in FIG. Therefore, the output voltage Vs obtained in the present embodiment shown in FIG. 2A can be ensured to be larger than those of Comparative Examples 1 and 2 shown in FIGS.

1.3. Bias Voltage for Spontaneously Polarizing Multiple Pyroelectric Capacitors FIG. 3 shows the spontaneous polarization when bias is applied to the capacitors Capa1 to Capa4 shown in FIG. Each of the capacitors Capa <b> 1 to Capa <b> 4 has a pyroelectric body 12 such as PZT between the first electrode 10 and the second electrode 14. When the brass terminal of the power source EA is connected to the external terminal TA1 and the negative terminal is connected to the external terminal TA2, and the electric field E shown in FIG. 3 is applied to the capacitors Capa1 to Capa4, the polarization directions are aligned.

  That is, in each of Capa1 to Capa4, the electric field E acts on the first electrode 10, the pyroelectric body 12, and the second electrode 14. For this reason, in each of Capa1 to Capa4, in the example of FIG. 3, the first electrode 10 side is positive and the second electrode 14 side is negative and the polarization direction is aligned and polarized. Then, even if the electric field E is canceled, the spontaneous polarization is maintained in each pyroelectric body 12 of Capa1 to Capa4.

  Here, as shown in FIG. 3, floating charges exist on the exposed surfaces of the first electrode 10 and the second electrode 14 in each of Capa1 to Capa4. In the example of FIG. 3, the floating charges of the first electrode 10 are negative and the floating charges of the second electrode 14 are positive, but the present invention is not limited to this. For example, electrode connection between adjacent capacitors of Capa1 to Capa4, such as connecting the first electrode 10 of the first capacitor Capa1 and the first electrode 10 of the second capacitor Capa2, is between the first and second electrodes 10 and 14. Various combinations such as the first electrodes 10 or the second electrodes 14 can be selected. The external terminal TA1 can be connected to one of the first and second electrodes 10 and 14 of the first capacitor Capa1, and the external terminal TA2 is similarly connected to the first and second electrodes 10 and 14 of the fourth capacitor Capa4. 14 may be connected.

  The principle of light detection using a pyroelectric capacitor is that the amount of spontaneous polarization of the pyroelectric capacitor after the release of the electric field E changes due to the pyroelectric effect (pyro electronic effect) due to heat based on light, and the amount of change is obtained. The amount of light (amount of heat) is detected. Therefore, the polarization state may be generated by applying the electric field E to Capa1 to Capa4 at least once at the time of manufacture or use before light detection.

1.4. Structure of Pyroelectric Detector FIG. 4 and FIG. 5 are a plan view and a cross-sectional view of a pyroelectric photodetector, for example, a pyroelectric infrared detector 200. In FIG. 4, four pyroelectric capacitors are connected in series as in FIG. 1, but FIG. 3 shows a state in which three pyroelectric capacitors are connected in series because of space. The pyroelectric infrared detector 200 includes a base 20, a support member (membrane) 30 provided on the base 20, and a plurality (four in FIG. 4) connected in series on the support member (membrane) 30. 5 is three) pyroelectric capacitors Capa1 to Capa4 (Capa1 to Capa3). The plurality of pyroelectric capacitors are collectively referred to as Capa.

  As shown in FIG. 4, the support member (membrane) 30 includes two arms 30-1 and 30-2, and the two arms 30-1 and 30-2 are supported by the base body 20. As shown in FIG. 5, the support member (membrane) 30 includes a first surface 30 </ b> A and a second surface 30 </ b> B that faces the first surface 30 </ b> A, and the cavity 100 is provided between the second surface 30 </ b> B and the base body 20. Is formed. The support member (membrane) 30 and the base body 20 are thermally separated by the hollow portion 100.

5 includes, for example, a silicon substrate 21 and an insulating film (SiO ₂ layer) 22 formed on the silicon substrate 21, and the cavity 100 is obtained by removing a part of the insulating film 22. Is formed. Elements 40 and 41 such as transistors can be formed in the element region 21 </ b> A of the silicon substrate 21.

  Regions other than the cavity portion 100 in the insulating layer 22 shown in FIG. Vias 31 and 32 can be provided in the holding portions 22A and 22B. The via 31 is connected to a wiring layer 33 provided in the insulating layer 22. The via 32 is connected to another wiring layer 34 provided in the insulating layer 22. The wiring layer 33 can be further connected to the elements 40 and 41 via contacts 35 and 36 provided in the insulating layer 22.

  Each of the plurality of pyroelectric capacitors Capa is provided on the side opposite to the first electrode (lower electrode) 10 on the support member (membrane) 30 side and the support member (membrane) 30 side. A second electrode (upper electrode) 14 smaller than the first electrode 10 and a pyroelectric body (for example, PZT layer: lead zirconate titanate layer) 12 provided between the first electrode 10 and the second electrode 14 are included. .

  Each of the plurality of pyroelectric capacitors Capa is covered with a metal compound layer 16 having an insulating property such as aluminum oxide, as shown in FIG. This metal compound layer 16 functions as a reducing gas barrier film. Thereby, in each of the plurality of pyroelectric capacitors Capa, the reduction gas (hydrogen, water vapor, OH group, methyl group, etc.) is prevented from entering the capacitor in the process after the capacitor is formed. This is because the pyroelectric body 12 is an oxide, and when the oxide is reduced, oxygen vacancies are generated and the pyroelectric effect is impaired. As described above, since the oxygen deficiency of the pyroelectric body 12 is prevented by the metal compound layer 16, each of the plurality of light absorption regions on the single support member 30 has a relatively small size. A plurality of pyroelectric capacitors Capa can be formed.

The metal compound layer 16 can include a first barrier layer (first layer film) 16A and a second barrier layer (second layer film) 16B, as shown in an enlarged view in FIG. The first barrier layer 16A can be formed by depositing a metal oxide such as aluminum oxide Al ₂ O ₃ by sputtering. Since no reducing gas is used in the sputtering method, the capacitor 230 is not reduced. The second barrier layer 16B can be formed, for example, by depositing aluminum oxide Al ₂ O ₃ by, for example, an atomic layer chemical vapor deposition (ALCVD) method. A normal CVD (Chemical Vapor Deposition) method uses a reducing gas, but the capacitor Capa is isolated from the reducing gas by the first barrier layer 16A.

Here, the total film thickness of the metal compound layer 16 is 50 to 70 nm, for example, 60 nm. At this time, the film thickness of the first barrier layer 16A formed by the CVD method is larger than that of the second barrier layer 16B formed by the atomic layer chemical vapor deposition (ALCVD) method, and becomes 35 to 65 nm, for example, 40 nm. In contrast, the thickness of the second barrier layer 16B formed by atomic layer chemical vapor deposition (ALCVD) can be reduced. For example, aluminum oxide Al ₂ O ₃ is formed to a thickness of 5 to 30 nm, for example, 20 nm. Is done. The atomic layer chemical vapor deposition (ALCVD) method has excellent embedding characteristics as compared with the sputtering method and the like, and thus can cope with miniaturization. The first and second barrier layers 16A and 16B The reducing gas barrier property can be enhanced. Also, the first barrier layer 16A formed by sputtering is not dense compared to the second barrier layer 16B, but it is effective and lowers the heat transfer rate. Since the first barrier layer 16A is interposed between the pyroelectric capacitor Capa and the second barrier layer 16B, heat dissipation from the pyroelectric capacitor Capa can be prevented.

  As shown in FIG. 5, an interlayer insulating film 17 is formed on the metal compound layer 16. Generally, when the source gas (TEOS) of the interlayer insulating film 17 chemically reacts, a reducing gas such as hydrogen gas or water vapor is generated. The first reducing gas barrier film 16 provided around the capacitor Capa protects the capacitor Capa from the reducing gas generated during the formation of the interlayer insulating film 17.

  As shown in FIG. 5, the wiring layer 18 is disposed on the interlayer insulating film 17. A first contact hole 17A and a second contact hole 17B are formed in the interlayer insulating film 17 in advance before the electrode wiring is formed. At that time, contact holes are similarly formed in the metal compound layer 16. The first electrode (lower electrode) 10 and the wiring layer 18 are electrically connected by the first plug 19A embedded in the first contact hole 17A. Similarly, the second electrode (upper electrode) 14 and the wiring layer 18 are electrically connected by the second plug 19B embedded in the second contact hole 17B.

  In the present embodiment, as shown in FIG. 5, the via 32 and the lower electrode 10 of Capa1 are connected by the wiring layer 18A, the upper electrode 14 of Capa1 and the lower electrode 10 of Capa2 are connected by the wiring layer 18B, and the Capa2 The upper electrode 14 and the lower electrode 10 of Capa3 are connected by a wiring layer 18C, and the upper electrode 14 of Capa3 and a via 31 are connected by a wiring layer 18D. In FIG. 4, similarly, four pyroelectric capacitors Capa1 to Capa4 are connected in series using the wirings 18A to 18E.

  The widths of the first wiring parts (wirings 18A and 18E in FIG. 4 and 18A and 18D in FIG. 5) connected to both ends of the plurality of pyroelectric capacitors connected in series and the external terminals TA1 and TA2 are plural. It can be made narrower than the width of the second wiring part (wirings 18B to 18D in FIG. 4 and 18B to 18C in FIG. 5) connecting the pyroelectric capacitors.

  In this way, the width of the first wiring part (wirings 18A and 18E in FIG. 4 and 18A and 18D in FIG. 5) serving as a heat outlet is reduced to suppress heat dissipation, while the second wiring part between the pyroelectric capacitors. (The wirings 18B to 18D in FIG. 4 and 18B to 18C in FIG. 5) are wide to suppress the voltage drop.

  Here, if the interlayer insulating film 17 does not exist, when the wiring layer 18 is subjected to pattern etching, the underlying metal compound layer 16 (second barrier layer 16B) is etched and the barrier property is deteriorated. The interlayer insulating film 17 is preferably formed on the metal compound layer 16 in order to ensure the barrier property of the metal compound layer 16.

  In addition, the interlayer insulating film 17 preferably has a low water content or a low hydrogen content. Therefore, the interlayer insulating film 17 is degassed by annealing. Thus, the hydrogen content or moisture content of the interlayer insulating film 17 is made lower than the light absorption layer 50 covering the wiring layer 18 and the posts (holding portions) 22A and 22B that are insulating films. In this way, even when the capacitor Capa is exposed to a high temperature after the interlayer insulating film 17 is formed, the generation of reducing gas from the interlayer insulating film 17 can be suppressed.

  6A and 6B show wiring examples of two Capans and Capan + 1 connected in series. As shown in FIG. 6A, the upper electrode 14 of Capan and the lower electrode 10 of Capan + 1 are not limited to being connected by the wiring layer 18, but the lower electrodes 10 of Ccapn and Capan + 1 are connected by the wiring layer 18. Can do. Thus, when connecting two Capan and Capan + 1, since the wiring 18 which connects the lower electrodes 10 does not need to be formed along the mountain-shaped capacitor, the wiring 18 becomes the shortest path. For this reason, a voltage drop becomes small and the fall of the output voltage Vs is suppressed.

  Alternatively, as shown in FIG. 6B, the wiring layer 18 can be omitted by using the lower electrode 10 of Ccapn and Capan + 1 as a common electrode. In this case, the wiring 18 can be omitted, and the common electrode can be formed wider and thicker than the wiring 18, so that the wiring resistance can be remarkably reduced. Thereby, a voltage drop becomes small and the fall of output voltage Vs can further be suppressed.

  6A and 6B, if the bias electric field E is applied as shown in FIG. 3, the polarization directions of Ccapn and Capan + 1 are uniquely determined.

  A light absorption layer 50 is formed on the pyroelectric capacitor Capa connected to the wiring as shown in FIG. When one light absorption layer 50 is disposed so as to cover the plurality of pyroelectric capacitors Capa1 to Capa3 shown in FIG. 5, regions of substantially equal area corresponding to the plurality of pyroelectric capacitors Capa1 to Capa3 are individual light absorption regions. . A plurality of divided light absorption layers 50a to 50c may be formed so as to cover the plurality of pyroelectric capacitors Capa1 to Capa3 shown in FIG. This has the advantage that the heat release speed of each of the pyroelectric capacitors Capa1 to Capa3 is increased and the thermal reset can be performed in a short time as compared with the case where one common light absorption layer 50 is provided.

  Although the embodiment described above has a planar structure in which the lower electrode 10 is wider than the upper electrode 14, the present invention can also be applied to a pyroelectric capacitor Capa having a stack structure as shown in FIG. In the pyroelectric capacitor Capa having the stack structure, as shown in FIG. 7, the cross-sectional areas of the first electrode 10, the pyroelectric body 12, and the second electrode 14 are substantially equal. Therefore, unlike the pyroelectric capacitor having the planar structure, the wiring to the first electrode 10 cannot be provided above the interlayer insulating layer 17.

  For this reason, the support member (membrane) 30 has a multi-layer structure, and one layer is a wiring 18B. The wiring 18B connects the first electrodes (lower electrodes) 10 of two adjacent pyroelectric capacitors Capa. The wiring 18B in the support member 30 is connected to the first electrodes (lower electrodes) 10 of the two pyroelectric capacitors Capa by plugs 19C and 19D filled in the contact holes 30C and 30D formed in the support member 30. .

1.5. Next, the relationship between the light absorption areas AR1 to AR4 and the outline of the pyroelectric body 12 will be examined. FIG. 8 shows an example in which the pyroelectric body 12 of each of the plurality of pyroelectric capacitors Capa1 to Capa4 is an n-shaped (n is an integer of 3 or more) square, for example, a square. The pyroelectric body 12 of the first pyroelectric capacitor Capa1 includes first to nth contour lines K1a to K4a. The light absorption area AR1 corresponding to the first pyroelectric capacitor Capa1 has an mth opposed contour line facing the mth contour line (1 ≦ m ≦ n) of the pyroelectric body 12 of the first pyroelectric capacitor Capa1. The distance dm (d1a, d2a, d3a, d4a) between the mth contour line and the mth counter contour line can be constant regardless of the value of m (d1a = d2a = d3a = d4a). Each of the pyroelectric bodies 12 of the other capacitors Capa2 to Capa4 also has an outline (n is an integer of 3 or more) square, for example, a quadrangle, and the first to nth outlines K1b to K4b, K1c to K1c, and K1d to K4da Including. Similarly, the distance dm between the mth contour line and the mth opposing contour line can be constant regardless of the value of m (d1b = d2b = d3b = d4b, d1c = d2c = d3c = d4c). , D1d = d2d = d3d = d4d).

  Thus, each one of the light absorption regions AR1 to AR4 and each of the pyroelectric bodies 12 of the plurality of pyroelectric capacitors Capa1 to Capa4 are similar n-gons. Therefore, in one light absorption region, the distance from the first centroid (G1a to G1d) to the m-th counter contour line is equal regardless of the value of m, and each pyroelectric body 12 of the plurality of pyroelectric capacitors Capa1 to Capa4 is also used. The distance from the second centroid (G2a to G2d) to the mth contour line is equal regardless of the value of m. Thereby, the heat generated in each of the light absorption regions AR1 to AR4 can be evenly collected in the pyroelectric body 12 of one pyroelectric capacitor Capa.

  In FIG. 2, the pyroelectric body 12 of each of the plurality of pyroelectric capacitors Capa1 to Capa4 has a circular outline. If the outline of the pyroelectric body 12 is a circle or an ellipse, the outline of the pyroelectric body 12 in FIG. The distance to the outline of the light absorption regions AR1 to AR4 varies depending on the position. Therefore, the uniformity of heat transfer is better in FIG. 8, but even if the pyroelectric body 12 has a circular or elliptical outline, the above-described difference in distance is relatively small, and thus the effect described in FIG. 2 is achieved. be able to.

1.6. Through-holes formed in support member FIGS. 9A and 9B show non-uniform heat transfer structures and heat transfer characteristics. FIG. 9A shows a layout example that does not satisfy the conditions described in FIG. 2 and FIG. In this case, in each of the light absorption regions AR1 to AR4, the length of the heat transfer path from the periphery of the light absorption regions AR1 to AR4 to the pyroelectric body 12 varies.

  FIG. 9B shows an example of non-uniform heat transfer characteristics. In the example of FIG. 9B, the peak positions of the heat flow rates TP1 to TP3 are aligned in three of the four pyroelectric bodies 12, but the peak levels of the heat flow rates TP1 to TP3 are different. To make matters worse, the peak position of the heat flow rate TP4 is shifted from the peak positions of the other three heat flow rates TP1 to TP3 in the remaining one of the four pyroelectric bodies 12. Therefore, when the heat flow rates TP1 to TP4 are sampled at a certain time, it can be seen that the output voltage Vs decreases compared to the case where the peak positions and peak levels of the four heat flow rates TP1 to TP4 are aligned. In this embodiment, the peak positions and peak levels of the four heat flow rates TP1 to TP4 can be made substantially the same.

  In the present embodiment, since a plurality of pyroelectric capacitors Capa are mounted on one support member 30, a space is secured between two adjacent pyroelectric capacitors Capa among the plurality of pyroelectric capacitors Capa. Therefore, as shown in FIG. 10, the support member 8 membrane) 30 has at least one through hole CN1 to CN6 in a region between two adjacent pyroelectric capacitors Capa among the plurality of pyroelectric capacitors Capa. Can do.

  Here, a sacrificial layer is embedded in the cavity 102 shown in FIG. 5 when the support member 30, pyroelectric capacitor Capa and the like are formed on the substrate 20. And after forming the material layer used as the support member 30 on the whole surface on the base | substrate 20, and forming pyroelectric capacitor Capa etc. on the material layer, the material layer used as the support member 30 is 2 as shown in FIG. The support member 20 having the arms 30-1 and 30-2 is etched into the shape. During the etching, the through holes CN1 to CN6 shown in FIG. 5 are also formed at the same time.

  Although the sacrificial layer is isotropically etched using an etchant, the through holes CN1 to CN6 are used as supply ports for the etchant. As a result, the etchant can easily reach the sacrificial layer below the support member 30 and the sacrificial layer can be easily removed by isotropic etching.

2. Second Embodiment FIG. 11 is a circuit diagram showing an example of a circuit configuration of a pyroelectric detection device (pyroelectric detection array). In the example of FIG. 11, a plurality of photodetection cells (that is, pyroelectric detectors 200a to 200d, etc.) are two-dimensionally arranged. Note that a plurality of pyroelectric capacitors Capa shown in FIG. 11 are connected in series as described above. A scanning line (W1a, W1b, etc.) and a data line (D1a, D1b, etc.) are selected in order to select one photodetection cell from a plurality of photodetection cells (pyroelectric detectors 200a-200d, etc.) Is provided.

  The pyroelectric detector 200a as the first photodetection cell includes a plurality of pyroelectric capacitors Capa connected in series and an element selection transistor M1a. The potential relationship between the two poles of the pyroelectric capacitor Capa is uniquely determined by the direction of the electric field E as shown in FIG. At the time of light detection, the output of the driver PDr1 is grounded. The other light detection cells have the same configuration. The size of the area occupied by one photodetection cell is, for example, 20 μm × 20 μm.

  The potential of the data line D1a can be initialized by turning on the reset transistor M2. When reading the detection signal, the read transistor M3 is turned on. A current generated by the pyroelectric effect is converted into a voltage by the I / V conversion circuit 510, amplified by the amplifier 600, and converted into digital data by the A / D converter 700.

  In the present embodiment, a plurality of pyroelectric detectors are two-dimensionally arranged (for example, arranged in an array along each of two orthogonal axes (X axis and Y axis)). A photodetector (pyroelectric optical array sensor) is realized.

3. Third Embodiment In this embodiment, an electronic device will be described.

3.1. Infrared Camera FIG. 12 shows a configuration example of an infrared camera 400A as an example of an electronic apparatus including the pyroelectric detector or pyroelectric detector of the present embodiment. The infrared camera 400A includes an optical system 400, a sensor device (pyroelectric detection device) 410, an image processing unit 420, a processing unit 430, a storage unit 440, an operation unit 450, and a display unit 460.

  The optical system 400 includes, for example, one or a plurality of lenses and a driving unit that drives these lenses. Then, an object image is formed on the sensor device 410. If necessary, focus adjustment is also performed.

  The sensor device 410 is configured by two-dimensionally arranging the pyroelectric detectors 200 of the present embodiment described above, and is provided with a plurality of row lines (word lines, scanning lines) and a plurality of column lines (data lines). . The sensor device 410 includes a row selection circuit (row driver), a readout circuit that reads data from the detector via a column line, an A / D conversion unit, and the like, in addition to the two-dimensionally arranged detectors. Can do. By sequentially reading data from each detector arranged two-dimensionally, it is possible to perform imaging processing of an object image.

  The image processing unit 420 performs various image processing such as image correction processing based on digital image data (pixel data) from the sensor device 410.

  The processing unit 430 controls the entire infrared camera 400A and controls each block in the infrared camera 400A. The processing unit 430 is realized by a CPU or the like, for example. The storage unit 440 stores various types of information, and functions as a work area for the processing unit 430 and the image processing unit 420, for example. The operation unit 450 serves as an interface for the user to operate the infrared camera 400A, and is realized by various buttons, a GUI (Graphical User Interface) screen, and the like. The display unit 460 displays, for example, an image acquired by the sensor device 410, a GUI screen, and the like, and is realized by various displays such as a liquid crystal display and an organic EL display.

  In this way, the pyroelectric detector for one cell is used as a sensor such as an infrared sensor, and the pyroelectric detector for one cell is two-dimensionally arranged in two axes, for example, two orthogonal axes. The sensor device 410 can be configured to provide a heat (light) distribution image. The sensor device 410 can be used to configure an electronic device such as a thermography, an in-vehicle night vision, or a surveillance camera.

  Of course, analysis equipment (measuring equipment) that analyzes (measures) physical information of objects by using a pyroelectric detector for one cell or multiple cells as a sensor, security equipment that detects fire and heat generation, factories, etc. Various electronic devices such as FA (Factory Automation) devices provided in the system can also be configured.

3.2. Driving Support Device FIG. 13 shows a configuration example of a driving support device 600 as an example of an electronic device including the pyroelectric detector or the pyroelectric light detection device of the present embodiment. The driving support device 600 includes a processing unit 610 having a CPU for controlling the driving support device 600, an infrared camera 620 capable of detecting infrared light with respect to a predetermined imaging region outside the vehicle, and a yaw rate sensor that detects the yaw rate of the vehicle. 630, a vehicle speed sensor 640 that detects the traveling speed of the vehicle, a brake sensor 650 that detects the presence or absence of a brake operation by the driver, a speaker 660, and a display device 670.

  For example, the processing unit 610 of the driving support apparatus 600 automatically detects an infrared image around the host vehicle obtained by imaging with the infrared camera 620 and a detection signal related to the traveling state of the host vehicle detected by the sensors 630 to 650. When an object such as a pedestrian or an object existing in the forward direction of the vehicle is detected and it is determined that there is a possibility of contact between the detected object and the host vehicle, the speaker 660 or the display device 670 Output an alarm.

  For example, as shown in FIG. 14, the infrared camera 620 is disposed near the center in the vehicle width direction at the front of the vehicle. The display device 670 includes a HUD (Head Up Display) 671 that displays various types of information at a position that does not obstruct the driver's forward view in the front window.

3.3. Security Device FIG. 15 shows a configuration example of a security device 700 as an example of an electronic device including the pyroelectric detector or the pyroelectric detector of the present embodiment.

  The security device 700 has at least an infrared camera 710 that captures a monitoring area, a human sensor 720 that detects an intruder in the monitoring area, and a movement that has entered the monitoring area by processing image data output from the infrared camera 710. A motion detection processing unit 730 that detects the body, a human sensor detection processing unit 740 that performs detection processing of the human sensor 720, and an image compression unit 750 that compresses image data output from the infrared camera 710 in a predetermined method. A communication processing unit 760 that receives compressed image data and intruder detection information, and receives various setting information from an external device to the security device 700, and condition setting and processing commands for each processing unit of the security device 700 And a control unit 770 that performs transmission and response processing by the CPU.

  The motion detection processing unit 730 includes a buffer memory (not shown), a block data smoothing unit to which the output of the buffer memory is input, and a state change detection unit to which the output of the block data smoothing unit is input. The state change detection unit of the motion detection processing unit 730 uses the same image data even in different frames taken by a moving image if the monitoring area is in a stationary state. A change in state is detected by utilizing the difference in data.

  For example, FIG. 16 shows the security device 700 installed under the eaves, the imaging area A1 of the infrared camera 710 incorporated in the security device 700, and the detection area A2 of the human sensor 720 from the side. .

3.4. FIG. 17 and FIG. 18 show a game machine 800 including a controller 820 using the above-described sensor device 410 as an example of an electronic apparatus including the pyroelectric detector or the pyroelectric detector of the present embodiment. A configuration example is shown.

  As shown in FIG. 17, the controller 820 used in the game machine 800 of FIG. 18 includes an imaging information calculation unit 830, an operation switch 840, an acceleration sensor 850, a connector 860, a processor 870, a wireless module 880, It is configured with.

  The imaging information calculation unit 830 includes an imaging unit 831 and an image processing circuit 835 for processing image data captured by the imaging unit 831. The imaging unit 831 includes a sensor device 832 (the sensor device 410 in FIG. 12), and an infrared filter (a filter that passes only infrared rays) 833 and an optical system (lens) 834 are disposed in front of the imaging unit 831. Then, the image processing circuit 835 processes the infrared image data obtained from the imaging unit 831 to detect a high-luminance portion, detects the position of the center of gravity and the area thereof, and outputs these data.

  The processor 870 outputs operation data from the operation switch 840, acceleration data from the acceleration sensor 850, and high-luminance partial data as a series of control data. The wireless module 880 modulates a carrier wave of a predetermined frequency with this control data and outputs it as a radio signal from the antenna 890.

  Data input through a connector 860 provided in the controller 820 is also processed by the processor 870 in the same manner as the above-described data, and is output as control data via the wireless module 880 and the antenna 890.

  As shown in FIG. 18, the game device 800 includes a controller 820, a game machine body 810, a display 811, and LED modules 812A and 812B, and a player 801 holds the controller 820 with one hand and plays a game. You can play. Then, when the imaging unit 831 of the controller 820 is directed to the screen 813 of the display 811, the imaging unit 831 detects infrared rays output from the two LED modules 812A and 812B installed in the vicinity of the display 811, and the controller In step 820, the position and area information of the two LED modules 812A and 812B are acquired as information on the high luminance point. Data on the position and size of the bright spot is transmitted from the controller 820 to the game machine body 810 wirelessly and received by the game machine body 810. When the player 801 moves the controller 820, the data of the position and size of the bright spot changes. By using this, the game machine body 810 can acquire an operation signal corresponding to the movement of the controller 820. The game can be advanced.

3.5. Body Temperature Measuring Device FIG. 19 shows a configuration example of a body temperature measuring device 900 as an example of an electronic device including the pyroelectric detector or the pyroelectric detector of the present embodiment.

  As shown in FIG. 19, the body temperature measurement device 900 includes an infrared camera 910, a body temperature analysis device 920, an information communication device 930, and a cable 940. The infrared camera 910 includes an optical system such as a lens (not shown) and the sensor device 410 described above.

  The infrared camera 910 captures a predetermined target area, and transmits image information of the captured subject 901 to the body temperature analyzer 920 via the cable 940. Although not shown, the body temperature analyzer 920 is an image reading processing unit that reads a heat distribution image from the infrared camera 910, and a body temperature analysis process that creates a body temperature analysis table based on data from the image reading processing unit and an image analysis setting table. The body temperature information transmission data is transmitted to the information communication device 930 based on the body temperature analysis table. The data for transmitting body temperature information may include predetermined data corresponding to abnormal body temperature. Further, when it is determined that a plurality of subjects 901 are included in the imaging region, information on the number of subjects 901 and the number of people with abnormal body temperature may be included in the body temperature information transmission data.

3.6. Specific Substance Detection Device FIG. 20 shows the absorption of the light absorbing material of the pyroelectric detector of the sensor device 410 described above as an example of the electronic device including the pyroelectric detector or pyroelectric detector of the present embodiment. An example in which a sensor device having a wavelength in the terahertz range is used as a terahertz light sensor device and the specific substance detection apparatus 1000 is configured in combination with a terahertz light irradiation unit.

  The specific substance detection apparatus 1000 includes a control unit 1010, an irradiation light unit 1020, an optical filter 1030, an imaging unit 1040, and a display unit 1050. The imaging unit 1040 includes an optical system such as a lens (not shown) and a sensor device in which the absorption wavelength of the light absorbing material of the pyroelectric detector described above is in the terahertz range.

  The control unit 1010 includes a system controller that controls the entire apparatus, and the system controller controls the light source driving unit and the image processing unit included in the control unit. The irradiation light unit 1020 includes a laser device that emits terahertz light (an electromagnetic wave having a wavelength in the range of 100 μm to 1000 μm) and an optical system, and irradiates the person 1060 to be inspected with terahertz light. The reflected terahertz light from the person 1060 is received by the imaging unit 1040 through the optical filter 1030 that allows only the spectral spectrum of the specific substance 1070 to be detected to pass. The image signal generated by the imaging unit 1040 is subjected to predetermined image processing by the image processing unit of the control unit 1010, and the image signal is output to the display unit 1050. The presence of the specific substance 1070 can be determined because the intensity of the received light signal varies depending on whether or not the specific substance 1070 is present in the clothes of the person 1060.

  Although some embodiments of the electronic device have been described above, the electronic device of the above embodiment is not limited to the configuration described, and some of the components (for example, an optical system, an operation unit, a display unit, etc.) are omitted. However, various modifications such as adding other components are possible.

3.7. Sensor Device FIG. 21A shows a configuration example of the sensor device 410 of FIG. The sensor device includes a sensor array 500, a row selection circuit (row driver) 510, and a readout circuit 520. An A / D converter 530 and a control circuit 550 can be included. The row selection circuit (row driver) 510 and the readout circuit 520 are referred to as a drive circuit. By using this sensor device, an infrared camera 400A used in, for example, a night vision device shown in FIG. 12 can be realized.

  In the sensor array 500, for example, as shown in FIG. 11, a plurality of sensor cells are arranged (arranged) in the biaxial direction. A plurality of row lines (word lines, scanning lines) and a plurality of column lines (data lines) are provided. One of the row lines and the column lines may be one. For example, when there is one row line, a plurality of sensor cells are arranged in the direction (lateral direction) along the row line in FIG. On the other hand, when there is one column line, a plurality of sensor cells are arranged in a direction (vertical direction) along the column line.

  As shown in FIG. 21B, each sensor cell of the sensor array 500 is arranged (formed) at a location corresponding to the intersection position of each row line and each column line. For example, the sensor cell of FIG. 21B is arranged at a location corresponding to the intersection position of the row line WL1 and the column line DL1. The same applies to other sensor cells.

  The row selection circuit 510 is connected to one or more row lines. Then, each row line is selected. For example, taking a QVGA (320 × 240 pixel) sensor array 500 (focal plane array) as shown in FIG. 21B as an example, row lines WL0, WL1, WL2,... WL239 are sequentially selected (scanned). Perform the action. That is, a signal (word selection signal) for selecting these row lines is output to the sensor array 500.

  The read circuit 520 is connected to one or more column lines. Then, a read operation for each column line is performed. Taking the QVGA sensor array 500 as an example, an operation of reading detection signals (detection current, detection charge) from the column lines DL0, DL1, DL2,.

  The A / D conversion unit 530 performs a process of A / D converting the detection voltage (measurement voltage, ultimate voltage) acquired in the reading circuit 520 into digital data. Then, the digital data DOUT after A / D conversion is output. Specifically, the A / D converter 530 is provided with each A / D converter corresponding to each of the plurality of column lines. Each A / D converter performs A / D conversion processing of the detection voltage acquired by the reading circuit 520 in the corresponding column line. Note that one A / D converter is provided corresponding to a plurality of column lines, and the detection voltage of the plurality of column lines can be A / D converted in a time division manner using this one A / D converter. Good.

  The control circuit 550 (timing generation circuit) generates various control signals and outputs them to the row selection circuit 510, the read circuit 520, and the A / D conversion unit 530. For example, a charge or discharge (reset) control signal is generated and output. Alternatively, a signal for controlling the timing of each circuit is generated and output.

  Although several embodiments have been described above, it is easily understood by those skilled in the art that many modifications can be made without substantially departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention. For example, a term described at least once together with a different term having a broader meaning or the same meaning in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings. For example, the base means any support structure such as a substrate, a base or base, and a support base.

  The present invention can be widely applied to various pyroelectric detectors. The wavelength of the light to detect is not ask | required. In addition, the pyroelectric light detector or the pyroelectric light detecting device, or the electronic device having them, for example, is a flow sensor that detects the flow rate of a fluid under a condition in which the amount of heat supplied and the amount of heat taken by the fluid are balanced. It can also be applied. Instead of the thermocouple provided in this flow sensor, the pyroelectric detector or pyroelectric detection device of the present invention can be provided, and objects other than light can be detected.

  As described above, according to at least one embodiment of the present invention, for example, the detection sensitivity of a pyroelectric detector can be significantly improved.

10 first electrode (lower electrode), 12 pyroelectric material, 14 second electrode (upper electrode),
16 metal compound layer, 18 wiring, 20 substrate, 30 support member, 50 light absorption layer,
100 cavity part, 200 detector, AR1-AR4 light absorption region,
Capa capacitor, CN1 to CN6 through hole, G1a to G1d first center of gravity,
G2a to G2d second center of gravity,
J1 to J4 A region in which the outline of the pyroelectric material is projected onto a two-dimensional surface,
K1a to K4d contour line, d1a to d4d distance,
TA1, TA2 External terminal

Claims (11)

A substrate;
A support member including a first surface and a second surface facing the first surface, the support member being disposed between the second surface and the base via a cavity portion;
A plurality of pyroelectric capacitors each including a pyroelectric material supported by the support member;
A light absorbing layer provided in contact with each of the plurality of pyroelectric capacitors;
Have
The plurality of pyroelectric capacitors are electrically connected;
The light absorption layer comprises a plurality of light absorption regions corresponding to each of the plurality of pyroelectric capacitors,
In plan view from the thickness direction of the substrate, the center of gravity of each of the plurality of light absorption regions exists at a position where each of the plurality of light absorption regions overlaps the pyroelectric body of each one of the pyroelectric capacitors corresponding thereto. A pyroelectric detector characterized by that. In claim 1,
The center of gravity of each of the plurality of light absorption regions has an overlap with the center of gravity of the pyroelectric body of each one of the plurality of light absorption regions corresponding to each of the plurality of light absorption regions in the plan view. Pyroelectric detector. In claim 1 or 2,
The pyroelectric body of each of the plurality of pyroelectric capacitors has an n-shaped outline (n is an integer of 3 or more) and includes a first outline to an n-th outline,
Each of the plurality of light absorption regions corresponding to each of the plurality of pyroelectric capacitors has an m-th opposing contour line facing the m-th contour line (1 ≦ m ≦ n) of the pyroelectric body,
A pyroelectric detector, wherein a distance dm between the m-th contour line and the m-th counter contour line is constant regardless of the value of m. In claim 1 or 2,
An outline of the pyroelectric body of each of the plurality of pyroelectric capacitors is a circle or an ellipse. In any one of Claims 1 thru | or 4,
Each of the plurality of pyroelectric capacitors includes a first electrode and a second electrode that sandwich the pyroelectric body, the first electrode is supported by the support member, and an area of the first electrode in the plan view A pyroelectric detector having a planar capacitor larger than the area of the second electrode. In any one of Claims 1 thru | or 5,
The pyroelectric detector of each of the plurality of pyroelectric capacitors, wherein a side surface of the pyroelectric body is covered with an electrically insulating metal compound layer. In any one of Claims 1 thru | or 6.
2. The pyroelectric detector according to claim 1, wherein the light absorption layer is composed of a plurality of light absorption layers that are divided and formed corresponding to each of the plurality of pyroelectric capacitors. In claim 7,
The pyroelectric detector according to claim 1, wherein the support member has a through hole in a region between two adjacent pyroelectric capacitors among the plurality of pyroelectric capacitors.   9. A pyroelectric detection device, wherein the pyroelectric detectors according to claim 1 are two-dimensionally arranged along two intersecting linear directions.   An electronic apparatus comprising the pyroelectric detector according to claim 1.   An electronic apparatus comprising the pyroelectric light detection device according to claim 9.

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