FR2866427A1 - Infrared radiation detector, has sensor arrays housed in case, including infrared radiation detection unit and detecting incident beam transmitted from different incidence direction by slits of case - Google Patents

Abstract

The detector (100) has a case (40) including slits for transmitting infrared rays. A group of sensor arrays (10t 1, 10t 2) includes an infrared radiation detection unit for detecting infrared radiation from the case, where the sensor arrays are housed in the case. Each sensor array detects an incident beam transmitted from different incidence direction by the slits of the case.

Description

ENCAPSULATED INFRARED RADIATION DETECTOR

  The present invention relates to an encapsulated detector of infrared radiation.

  An example of small encapsulated detectors of infrared radiation is described in Japanese Unexamined Publication Publication Publication No. 2003-270047.

  Fig. 9, appended to the present application, is a schematic sectional view of an infrared radiation detector described in the previously mentioned publication.

  In the infrared radiation detector 90 in Fig. 9, a sensor element 91, which detects infrared radiation, and a printed circuit board 92, on which a signal processing circuit is formed for processing the output signals of the sensor element 91 are formed separately from one another. The sensor element 91 comprises a membrane portion 91a which is formed as a thin-walled portion and a thick-walled portion 91b. The hot contacts as thermocouple measuring junctions (not shown) are disposed on the membrane portion 91a and the cold contacts as reference junctions of the thermocouples are disposed on the thick wall portion 91b. In the sensor element 91 having such a membrane portion 91a, the heat is less likely to escape from the hot contacts made as infrared radiation detecting elements towards the thick-walled portion 91b. Therefore, the sensor element 91 can detect infrared radiation with high sensitivity.

  In the infrared radiation detector 90, the sensor element 91 is stacked and disposed on the printed circuit board 92, and these elements are housed in a housing that includes a base 93, a hood 94 and a filter 95. Unlike infrared radiation detectors, in which a sensor element 91 and a printed circuit board 92 are arranged side-by-side, it is possible to reduce the size of infrared radiation detectors 90, in which a sensor element 91 and a circuit board 92 are stacked.

  When infrared radiation arriving from different directions is detected using an infrared radiation detector 90 shown in Fig. 9, there is a problem. A certain number of infrared radiation detectors 90 equal to the number of detection directions must be prepared, and they must be arranged by orienting them in these directions. Otherwise, an infrared detector 90 must be scanned in the individual detection direction. But in all cases, the size and the cost of the entire detector are increased.

  Given the problem described above, an object of the present invention is to provide a small inexpensive encapsulated detector of infrared radiation, able to detect infrared radiation arriving in different directions.

  The problem is solved using an encapsulated infrared radiation detector, of the type comprising: a housing having a window for transmitting infrared radiation, and a plurality of sensor chips having an infrared radiation detecting device for detecting the infrared radiation, characterized in that the sensor chips are housed in the housing, and each sensor chip is able to detect a different incident beam transmitted in a different incidence direction through the housing window.

  In the detector indicated above, each sensor chip is suitably positioned so that infrared radiation arriving in a different incidence direction through the housing window is radiated towards the infrared radiation detecting device. of the sensor chip. Therefore the detector can detect the infrared radiation transmitted in different directions through the window so that the dimensions of the detector are reduced. In addition, the cost of manufacturing the detector is reduced. Therefore, the detector for detecting multiple infrared radiation radiated from different incidence directions has small dimensions and is manufactured at a low cost.

  Preferably, the window is disposed just above the sensor chips, and the window has an area equal to or less than a total area of the sensor chips. More preferably, the window is parallel to the sensor chips. In addition, preferably, the window and the sensor chips are between them a predetermined angle.

  Preferably, the detector further comprises: control means of the incident beam for controlling the direction of incidence of the infrared radiation, and the infrared radiation transmitted by the window is controlled by the control means of the incident beam. In this case the infrared radiation is accurately selected so that the selected infrared radiation arriving in a predetermined incidence direction is accurately detected by the detector.

  Preferably, the control means of the incident beam 35 is a prism, a deflector or a reflector.

  In this case, the control means of the incident beam are small parts that can be housed in the housing.

  Preferably the detector further comprises a circuit chip having an input / output control circuit for controlling the sensor chip. The circuit chip is housed in the housing. In this case, since the sensor chip and the circuit chip are housed in the same housing, the dimensions of the detector are reduced.

  Preferably, the circuit chip comprises a plurality of input / output control circuits, each of which can respectively control the sensor chip. In this case, multiple I / O control circuits are formed on a circuit chip so that the sensor dimensions are reduced.

  Preferably the sensor chips are arranged on the circuit chip. Specifically, the sensor chips are superimposed on the circuit chip.

  Preferably, the detector further comprises means for controlling the incident beam to control the direction of incidence of the infrared radiation, and the infrared radiation transmitted by the window is controlled by the incident beam control means, and the control means incident beam are housed in the housing.

  Preferably the sensor chip includes a substrate having a membrane in the form of a thin portion of the substrate. The infrared radiation detection device includes a thermocouple and an infrared radiation absorbing film disposed on the substrate. The thermocouple includes a measurement junction disposed on the membrane and a reference junction disposed on the substrate, outside the membrane. The infrared radiation absorbing film is disposed on the substrate so as to cover the measurement junction. The infrared radiation detecting device can detect the infrared radiation based on a variation of the electromotive force of the thermocouple modified by a temperature difference between the measurement junction and the reference junction in the case where the detection device of the Infrared radiation receives infrared radiation.

  In the aforementioned detector, the heat at the measurement junction as the hot contact is not removed from the substrate side so that the infrared radiation can be accurately detected. This is why the detector comprising multiple sensor chips capable of detecting the infrared radiation with great precision is produced with a low cost.

  Preferably, the thermocouple includes two different films arranged on the substrate, and the two different films are alternately arranged in series so that the measurement junction and the reference junction are formed alternately by a plurality of portions of connections between the two films. different. In this case, the thermopile-type infrared radiation detection device can generate an intense output signal from the sensor so that the detector has a high sensitivity. Therefore, the low cost detector has small dimensions and high sensitivity.

  Preferably, the substrate is formed of a semiconductor substrate and the infrared radiation detecting device is disposed on the substrate by interposing an insulating film. In this case the detector can be manufactured using a conventional semiconductor processing method, so that the cost of manufacturing the detector is reduced.

  Preferably, the semiconductor substrate has a surface which is etched to form a membrane, this surface being located opposite the infrared radiation detection device.

  Preferably, the semiconductor substrate has a surface that is etched to form the membrane, which surface is on the same side as the infrared radiation detecting device.

  In addition, an encapsulated infrared radiation detector includes a housing having a first window and a second window for transmitting infrared radiation, and first and second sensor chips having an infrared radiation detecting device for detecting the infra-red radiation. -red, characterized in that the first and second sensor chips are housed in the housing, and in that each sensor chip is able to detect a different incident beam transmitted in a different incidence direction through the housing window .

  In the detector indicated above, each sensor chip is suitably positioned so that infrared radiation arriving in a different incidence direction through the housing window is radiated towards the infrared radiation detection device of the sensor chip. . Therefore the detector can detect infrared radiation transmitted in different directions by the windows so that the dimensions of the detector are reduced. In addition, the cost of manufacturing the detector is reduced. Therefore the detector for detecting multiple infrared rays emitted in different incidence directions has small dimensions and is manufactured at a low cost.

  Preferably, the first window is disposed just above the first sensor chip and the first window has an area equal to or less than a surface of the first sensor chip, and the second window is disposed just above the first sensor chip. second sensor chip and the second window has an area equal to or less than a surface of the second sensor chip. More preferably, the first window is parallel to the first sensor chip, and the second window is parallel to the second sensor chip. In addition, preferably, the first window and the first sensor chip have a predetermined angle between them, and the second window and the second sensor chip have another predetermined angle therebetween.

  Other characteristics and advantages of the present invention will emerge from the description given hereinafter with reference to the accompanying drawings, in which: FIG. 1 is a cross-sectional view showing an infrared radiation detector according to a first form embodiment of the present invention; FIG. 2A is a cross-sectional view showing a sensor chip of the detector; Fig. 2B is a plan view showing the sensor chip; Fig. 2C is a circuit diagram for explaining an output signal of the sensor chip according to the first embodiment; FIG. 3 is a cross-sectional view showing another infrared radiation detector according to a first variant of the first embodiment; FIG. 4 is a cross-sectional view showing another infrared radiation detector according to a second variant of the first embodiment; FIG. 5A is a cross-sectional view showing an infrared radiation detector according to a second embodiment of the present invention, and FIG. 5B is a cross-sectional view showing another infrared radiation detector according to a first variant of FIG. the second embodiment; FIG. 6A is a cross-sectional view showing another infrared radiation detector according to a second variant of the second embodiment, and FIG. 6B is a cross-sectional view showing another infrared radiation detector according to a third embodiment. variant of the second embodiment; FIG. 7A is a cross-sectional view showing another infrared radiation detector according to a fourth variant of the second embodiment; FIG. 7B is a sectional view showing another infrared radiation detector according to a fifth variant of the second embodiment; embodiment, and Fig. 7C is a cross-sectional view showing another infrared radiation detector according to a sixth variant of the second embodiment; Fig. 8A is a cross-sectional view showing the infrared radiation detector according to a third embodiment of the present invention; Fig. 8B is a cross-sectional view showing another infrared radiation detector according to a first modification of the third embodiment, and Fig. 8C is a cross-sectional view showing another infrared radiation detector according to a second variant of the third embodiment; and FIG. 9, of which reference has already been made, is a cross-sectional view showing an infrared radiation detector of the prior art.

  FIG. 1 is a schematic sectional view of a first embodiment of an infrared radiation detector 100. The infrared radiation detector 100 shown in FIG. 1 comprises two sensor chips 10t1 and 10t2, on which are formed infrared radiation detection elements, and two circuit chips 20t1 and 20t2, on which the control circuits are formed to control the input and output of the infrared radiation detection elements. The sensor chips 10t1 and 10t2 are stacked and arranged above the circuit chips 20t1 and 20t2. These elements are housed in a housing comprising a base 30 and a cover 40 equipped with 40fa and 40fb filters as windows that allow the passage of infrared radiation, and encapsulated. The base 30 and the cover 40 are united by welding and the housing is filled with nitrogen.

  In FIG. 1, the two sensor chips 10t1 and 10t2 have the same structure, and the two circuit chips 20t1 and 20t2 have the same structure.

  Figures 2A to 2C show the detail of the sensor chip. Figure 2A is a schematic sectional view of the sensor chip 10t and Figure 2B is a schematic top plan view. Fig. 2C is a schematic representation illustrating the arrangement of the infrared radiation sensing element 10 formed on the sensor chip 10t and illustrating how the output signal of the sensor is delivered.

  As shown in FIG. 2A, the sensor chip 10t is constituted by a semiconductor substrate 1 made of silicon (Si) and has a membrane 10m, which is arranged in the form of a thin-walled part, obtained by substrate attack from the underside. The infra-red radiation detecting element 10 is formed above the semiconductor substrate 1 with an interposed insulating film 2. The infrared radiation detecting element 10 formed on the semiconductor substrate 1 comprises thermocouples 10a and an infrared radiation absorbing film 10b.

  As shown in FIG. 2B, the thermocou-35pies 10a are arranged in such a way that the membrane 10m1 is surrounded by the latter.

  As shown in FIG. 2c, the thermocouples 10a are arranged as follows: a plurality of sets of films formed of two different materials 10ax and 10ay are extended in series on the semiconductor substrate 1 (thermopile) and their junctions establish in a manner alternated 10ah hot contacts and 10ac cold contacts. An example of the combination of films made of different materials 10a1 and 10y is a combination of an aluminum film and a polysilicon film. As shown in FIGS. 2A and 2C, the hot contacts 10a1 of the thermocouples 10a are formed on the 10m membrane which has a low heat capacity. The cold contacts 10ac of the thermocouples 10a are formed outside the membrane 10m on the thick-walled portion 10n which has a high heat capacity. In the infrared radiation detecting element 10, as shown in FIG. 2A, the infrared radiation absorbing film 10b is formed on the membrane 10m so that the hot contacts 10ah are covered by this film.

  When infrared radiation is emitted by the body of a human being or the like, the infrared radiation is absorbed by the infrared ray absorption film 10b, and an increase in the temperature of this film occurs. . As a result, the temperature of the hot contacts 10ah, which are arranged below the infrared radiation absorbing film 10b, increases. The temperature of the cold contacts 10ah does not increase since the thick-walled portion 1On acts as a heat sink.

  Therefore, the cold contacts 10ac serve as reference point for the temperature measurement. As previously mentioned, the infrared ray detecting element 10 changes the electromotive force of the thermocouples 10a due to the temperature difference produced between the hot contacts 10ah and the cold contacts 10ac when infrared radiation is received (Seebeck effect ). Infrared radiation is detected on the basis of the modified electromotive force. Thermocouples 10a shown in FIG. 2c constitute a thermopile. Therefore, the sum of the electromotive forces generated in the individual sets of the different materials 10ax and 10ay provides the output signal of the element 10 for detecting infrared radiation.

  In the sensor chip 10t having the membrane 10m, shown in Figs. 2A-2C, the heat is less likely to escape from the hot contacts 10ah of the thermocouples 10a towards the thick-walled portion 10n. Therefore the sensor chip 10t is able to detect infrared radiation with high accuracy. The thermocouples 10a formed to form a thermopile provide a high electromotive force (sensor output signal), and therefore an infra-red radiation sensing element having a high sensitivity and accuracy can be obtained.

  The infrared radiation detector 100, shown in FIG. 1, can detect infrared radiation L1 and L2 passing through the filters 40fa and 40fb constituting windows for transmitting infrared radiation and arrive in different directions. In the infrared radiation detector 100, the filters 40fa and 40fb and the sensor chips 10t1 and 10t2 are suitably arranged such that the following occur: the infrared radiation LO, indicated by arrows represented by a Dashed thick line, which passes through the filters 40fa and 40fb provided in the hood 40 and arrives at the top, is applied in an identical manner to the respective sensor chips 10t1 and 10t2, as shown in the figure. The infrared radiation L1 and L2, indicated by arrows represented by thick solid lines, which pass through the filters 40fa and 40fb and arrive in different directions, are applied differently. That is, the infrared radiation L1 and L2 are respectively applied to the infrared radiation sensing elements of the corresponding sensor chips 10t2 and 10t1 as shown in the figure. Therefore, the infrared radiation detector 100 shown in Fig. 1 is arranged as an infrared radiation detector, which is able to detect the following: the infrared radiation Li and L2, which pass through the filters 40fa and 40fb arranged as windows for transmitting infrared radiation, arriving in different directions.

  The infrared radiation detector 100 in FIG. 1 provides the advantage indicated below in contrast to the case where a certain number of infrared radiation detectors, equal to the number of detection directions, are prepared or in the case where a radiation detector Infrared is made to perform a scan: the size of the entire detector can be reduced and the cost of the entire detector can be reduced. In the infrared radiation detector 100 shown in FIG. 1, not only the batch sensor chips and 10t2 are housed in the case, but also the circuit chips 20t1 and 20t2, on which the circuits are formed for the control of the input and output sensor chips 10t1 and 10t2, are housed in the same housing and encapsulated together. This also reduces the size and cost of the entire detector as opposed to infrared radiation detectors, in which a sensor chip and a circuit chip are encapsulated separately. In the infrared ray detector 100 of FIG. 1, in addition, the sensor chips 10t1 and 10t2 and the circuit chips 20t1 and 20t2 are stacked and arranged. Therefore, the infrared radiation detector also has smaller dimensions compared to infrared radiation detectors, in which the sensor chips and the circuit chips are all arranged side by side.

  Therefore, the infra-red radiation detector 100 in FIG. 1 is arranged as a small inexpensive encapsulated infrared radiation detector, which is able to detect infrared radiation L1 and L2 arriving in different directions.

  FIG. 3 is a schematic sectional view of another infrared radiation detector 101. In relation to the infrared radiation detector 101 shown in FIG. 3, the same elements as in the infrared radiation detector 100 in FIG. marked by the same reference numbers.

  In the infrared radiation detector 101 of FIG. 3, the input / output control circuits respectively corresponding to the two sensor chips 10t1 and 10t2 are formed in a single circuit chip 20t. As a result, the base 31 and the cover 41 are reduced in size with respect to the infrared radiation detector 100 of FIG. 1, in which the circuit chips 20t1 and 20t2 respectively corresponding to the sensor chips 10t1 and 10t2 are provided separately. This is why the whole detector has a reduced size. By uniting the circuit chips into a single 20t chip, it is also possible to reduce the cost of the entire detector. As with the infrared radiation detector 100 shown in FIG. 1, the infrared radiation detector 101 shown in FIG. 3 is able to detect the infrared radiation L1 and L2 which pass through the filters 40fa and 40fb and arrive in different directions.

  FIG. 4 is a schematic sectional view of another infrared radiation detector 102. In connection with the infrared radiation detector 102 shown in FIG. 4, the same elements as those contained in the infrared radiation detector 101 of the FIG. 3 are designated by the same reference numbers.

  The infrared radiation detector 102 of FIG. 4 differs from the infrared radiation detector 101 of FIG. 3 in the following: the shape of the hood 42 and the arrangement of the filters 40fa and 40fb as windows transmitting infrared radiation with respect to two sensor chips 10t1 and 10t2. In the infrared radiation detector 101 of FIG. 3, the proportion of infrared radiation Li and L2 arriving on the side is small compared to the infrared radiation LO which arrives from the top. On the other hand, in the infrared radiation detector 102 of FIG. 4, the proportion of the infrared radiation L1 and L2 arriving on the side is increased relative to the infrared radiation LO arriving from the top. This is due to the fact that the cover 42 is more widely open for infrared radiation L1 and L2 arriving laterally. Therefore, the infrared radiation detector 102 of Figure 4 is less sensitive to infrared radiation LO arriving from the top. As a result, the infrared radiation detector 102 is able to detect the infrared radiation L1 and L2 passing through the filters 40fa and 40fb and arrive in different directions with increased reliability.

  The infrared radiation detector of the first embodiment is an infrared radiation detector designed to detect infrared radiation passing through windows in its housing and arriving in different directions. The infrared radiation detector according to a second embodiment is further provided with incidence control means, which controls the incidence directions of the infrared radiation. Hereinafter, a description of this embodiment will be given with reference to the drawings.

  Figs. 5A and 5B are schematic sectional views of infrared radiation detectors 103 and 104 of this embodiment.

  The infrared radiation detectors 103 and 104 shown in FIGS. 5A and 5B are infrared radiation detectors respectively obtained by addition of the following to the infrared radiation detector 100 of FIG. 1, and to the infrared radiation detector 101 of FIG. 3: prisms 50a and 50b as incidence control means which control the incidence directions of infrared radiation. In FIGS. 5A and 5B, infrared radiations LO coming from above are not shown to preserve the simplicity of the representation.

  In the infrared detectors 103 and 104 provided with the prisms 50a and 50b, the following occurs: as shown in the figures, the infrared radiation L3 and L4, which arrive in different directions, are refracted by the prisms 50a and 50b , and are applied to the individual sensor chips 10t1 and 10t2.

  In the infrared radiation detectors 103 and 104, the infrared radiation L3 and L4 in the detection direction can be more reliably selected by means of appropriate adjustment of the apex angle of the prisms 50a and 50b. As a result, the infrared radiation L3 and L4 arriving in different directions can be detected in a very precise manner.

  In the infrared radiation detectors 103 and 104 of Figs. 5A and 5B, as mentioned above, the prisms 50a and 50b are disposed outside the hoods 40 and 41. Instead, the prisms 50a and 50b may be disposed at inside the covers 40 and 41 and be housed in the encapsulation elements. In this case, the prisms 50a and 50b are easier to maintain since the prisms 50a and 50b are not exposed to the outside.

  Figs. 6A and 6B are schematic sectional views of other infrared radiation detectors 105 and 106 in this embodiment.

  The infrared radiation detectors 105 and 106 of FIGS. 6A and 6B are infrared radiation detectors respectively obtained by adding the following to the infrared radiation detector 100 of FIG. 1 and the infrared radiation detector 101 of FIG. 3: deflectors (i.e., protection plates) 60a and 60b as incidence control means, which control the incidence directions of the infrared radiation.

  In the infrared radiation detectors 105 and 106 of FIGS. 6A and 6B, as shown in these figures, infrared radiation LO coming from the top is blocked by the deflectors 60a and 60b. As a result, the infrared radiation LO is not applied to the individual sensor chips 10t1 and 10t2. This is why in infrared radiation detectors 105 and 106, the influence of infrared radiation LO coming from above can be eliminated. As a result, the infrared radiation L1 and L2 in the detection directions can be more reliably selected. Therefore, infrared radiation L1 and L2 arriving in different directions can be detected with great accuracy.

  Figs. 7A to 7C are schematic sectional views of other infrared radiation detectors 107 to 109 in this embodiment.

  The infrared radiation detectors 107 and 108 shown in FIGS. 7A and 7B are infrared radiation detectors respectively obtained by adding the following to the infrared radiation detector 100 of FIG. 1 and to the infrared radiation detector 101 of FIG. the reflectors 70 and 71 as incidence control means, which control the directions of incidence of the infrared radiation. In FIGS. 7A and 7B, the infrared radiation L0, which comes from above, is not shown to preserve the simplicity of the drawing.

  In the infrared radiation detector 100 of FIG. 1 and in the infrared radiation detector 101 of FIG. 3, as mentioned above, the infrared radiation L1, which passes through the filter 40fa, is applied to the sensor chip 10t2. and the infrared radiation L2, which passes through the filter 40fb, is applied to the sensor chip 10t1. In the infrared radiation detectors 107 and 108 equipped with the reflectors 70 and 71 in FIGS. 7A and 7B, the infrared radiations are applied differently: the infrared radiation L1, which passes through the filter 40fa, is applied to the sensor chip 10t1, and the infrared radiation L2, which passes through the filter 40fb, is applied to the sensor chip 10a2.

  In the infrared radiation detectors 107 and 108 equipped with reflectors 70 and 71, the infrared radiation L1 and L2 in the detection directions can be more reliably selected by appropriate adjustment of the angles of the surfaces of the reflectors 70 and 71. As a result, the infrared radiation L1 and L2, which arrive in different directions, can be detected with great precision.

  The infrared radiation detector 109 shown in Fig. 7C comprises three sensor chips 10t1 through 10t3, and a circuit chip 21t. The three sensor chips 10t1 to 10t3 are stacked and disposed above the circuit chip 21t. These elements are housed in a housing comprising a base 32 and a cover 43 provided with 40fa filters 40fc in the form of infrared transmission windows and are encapsulated. The infrared radiation detector 109 in Fig. 7C is also provided with reflectors 72 and 73 as incidence control means, which control the incidence directions of the infrared radiation.

  The infrared radiation detector 109 of FIG. 7C is able to detect the infrared radiation LO to L2 arriving in different directions as shown in the figure. The surfaces of the reflectors 72 and 73 on the side of the sensor chip 10t2 are covered so as to prevent reflection of the infrared radiation. This is intended to reliably select infrared radiation that arrives from the top.

  The infrared radiation detectors 103 to 109 of this embodiment, shown in FIGS. 5A and 5B to 7A-7C, are provided with prisms, deflectors or reflectors as incidence control means which control the directions. incidence of infrared radiation. The infrared radiation, which passes through the windows and arrives in different directions through these incidence control means, is detected by a plurality of sensor chips, respectively. In the infrared radiation detectors 103 to 109 of this embodiment, the infra-red radiation in the detection directions can be more reliably selected by use of the incidence control means. As a result, infrared radiation from different directions can be detected with great accuracy.

  Any incidence control means such as a prism, deflector, reflector or the like, is a small component, and these components may be housed together with a plurality of sensor chips in a housing and encapsulated.

  As previously mentioned, the infrared radiation sensors 103 to 109 of this embodiment, which are shown in Figs. 5A and 5B to 7A-7C, can detect infrared radiation arriving in different directions with great accuracy. The infrared radiation detectors 103 to 109 may be formed as small, inexpensive encapsulated detectors for infrared radiation. As previously mentioned, the infrared radiation detectors 103 to 109 shown in FIGS. 5A, 5B through 7A through 7C only use prisms, baffles or reflectors. Instead, infrared radiation detectors 103 to 109 can use any combination of such systems.

  The sensor chips 10t1 to 10t3 contained in the infrared radiation detectors 100 to 109 shown in FIGS. 1 to 7A to 7C are sensor chips, in which a membrane is formed on a semiconductor substrate, as has been so described. 2. In addition, the membranes are formed by etching the semiconductor substrate from the bottom face, or the side opposite the side where the infrared radiation sensing elements are formed. However, the sensor chip used in the infrared radiation detectors according to the present invention is not limited to this arrangement. The membrane may be formed by etching the semiconductor substrate from the side of the main surface or the same side as that on which the infrared radiation sensing elements are formed.

  Figs. 8A-8C are schematic cross-sectional views of the infrared radiation detectors 110-112 according to a third embodiment of the present invention, wherein such lit and read sensor chips are used.

  When a semiconductor substrate is used for the sensor chip on which the infrared radiation sensing element is formed, the membrane can be easily formed using common semiconductor processing techniques. This is why the membrane can be made at a low cost, and this is desirable. However, the sensor chip on which the infrared radiation detecting element is formed is not limited to this arrangement, and a substrate made of any material, such as glass, can be used for this purpose. To obtain a high sensitivity infrared radiation sensing element, it is preferable that the membrane is formed on a substrate.

  However, sensor chips without a membrane are also effective. It is not mandatory to use thermocouples in the infrared radiation detecting element and such an element can be arranged so that infrared radiation is detected using temperature variations of the resistive value. a resistive element formed of a thin film.

  The invention may be subject to changes and modifications which will be understood to be within the scope of the present invention.

Claims (21)

  An encapsulated infrared radiation detector, of the type comprising: a housing (30-32,40-43) having a window (40fa, 40fb, 40fc) for transmitting infra-red radiation, and a plurality of sensor chips (10t , 10t1-10t3, beds, 11t2) having a device (10) for detecting infrared radiation for detecting infrared radiation, characterized in that the sensor chips (10t, 10t1-10t3, 11tl, 11t2) are housed in the housing (30-32, 40-43), and each sensor chip (10t, 10t1-10t3r beds, lite) is able to detect a different incident beam transmitted in a different incidence direction through the window (40fa, 40fb, 40fc) of the housing (30-32, 40-43).   2. Detector according to claim 1, characterized in that the window (40fa, 40fb, 40fc) is arranged just above the sensor chips (10t, 10t1-10t3, 11tl, llt2), and the window (40fa, 40fb , 40fc) has an area equal to or less than a total area of the sensor chips (10t, 10t1-10t3, 11tl, 11t2).   3. Detector according to claim 2, characterized in that the window (40fa, 40fb, 40fc) is parallel to the sensor chips (10t, 10t1-10t3, lltl, llt2).   4. Detector according to claim 2, characterized in that the window (40fa, 40fb) and the sensor chips (10t, i0t1,10t2) are between them a predetermined angle.   5. Detector according to any one of claims 1 to 4, characterized in that it further comprises: means (50a, 50b, 60a, 60b, 70-73) for controlling the incident beam to control the direction of incidence of infrared radiation, and that the infrared radiation transmitted by the window (40fa, 40fb, 40fc) is controlled by means (50a, 50b, 60a, 60b, 7073) for controlling the incident beam.   6. Detector according to claim 5, characterized in that the means (50a, 50b) for controlling the incident beam are a prism (50a, 50b).   7. Detector according to claim 5, characterized in that the means (60a, 60b) for controlling the incident beam are a deflector (60a, 60b).   8. Detector according to claim 5, characterized in that the means (70-73) for controlling the incident beam are a reflector (70-73).   9. The detector as claimed in claim 1, further comprising: a circuit chip sensor chip (10t, 10t1-10t3, llt1, llt2), and that the circuit chip (20t, 20t1, 20t2, 21t) is housed in the housing (30-32,40-43).   10. Detector according to claim 9, characterized in that the circuit chip (20t, 20t1,20t2r21t) includes a plurality of input / output control circuits, each of which can respectively control the sensor chip (10t1- 1013, 1111, 1112).   11. Detector according to either of claims 9 and 10, characterized in that the sensor chips (10t, 10t1-10t3, beds, 11t2) are arranged on the circuit chip (20t, 20t1, 20t2, 21t). 12. Detector according to any one of claims 9 to 11, characterized in that it further comprises: means (50a, 50b, 60a, 60b, 70-73) for controlling the incident beam to control the direction infrared radiation, and the infrared radiation transmitted through the window (40fa, 40fb, 40fc) is controlled by the incident beam control means (50a, 50b, 60a, 60b, 70-73), and the control means (50a, 50b, 60a, 60b, 70-73) of the incident beam are housed in the housing (30-32,40-43).   13. Detector according to any one of claims 1 to 12, characterized in that the sensor chip (10t, 10t1-10t3, lltl, llt2) includes a substrate (1) having a membrane (10m) in the form of a thin portion of the substrate (1), that the infrared radiation detecting device (10) includes a thermocouple (10a) and an infrared radiation absorbing film (10b) disposed on the substrate (1), that the thermocouple (10a) includes a measuring junction (10ah) disposed on the membrane (10m) and a reference junction (10ac) disposed on the substrate (1), outside the membrane (10m), that the film (10b) of The absorption of the infrared radiation is arranged on the substrate (1) so as to cover the measurement junction (10ah), and the infrared radiation detection device (10) can detect the infrared radiation on the basis of a variation. the electromotive force of the thermocouple (10a) modified by a temperature difference between the measurement anointing (10ah) and the reference junction (10ac) in the case where the infrared radiation detection device (10) receives infrared radiation.   14. Detector according to claim 13, characterized in that the thermocouple (10a) includes two different films (10ax, 10ay) arranged on the substrate (1), and that the two different films (10ax, 10ay) are arranged alternately in series so that the measuring junction (10ah) and the reference junction (10ac) are formed alternately by a plurality of connection portions (10ah, 10ac) between the two different films (10ax, 10ay).   15. Detector according to claim 13 or 14, characterized in that the substrate (1) is formed of a semiconductor substrate (1), and that the device (10) for detecting the Infrared radiation is disposed on the substrate (1) by interposing an insulating film (2).   16. Detector according to claim 15, characterized in that the semiconductor substrate (1) has a surface, which is etched to form the membrane (10m), this surface being located opposite the device (10) for detecting radiation. infrared.   17. Detector according to claim 15, characterized in that the semiconductor substrate (1) has a surface, which is etched to form the membrane (10m), this surface being located on the same side as the device (10) for detecting the radiation infrared.   18. Encapsulated infrared radiation detector, comprising a housing (30-31, 40-42) having a first window (40fa) and a second window (40fb) for transmitting infrared radiation, and first and second sensor chips (10t, 10t1, 10t2, 11tl, lite) having a device (10) for detecting infrared radiation for detecting infrared radiation, characterized in that the first and second sensor chips (10t, 10t1, 10t2, llt1, lite) are housed in the housing (30-31, 40-42), and each sensor chip (10t, 10t1, 10t2, 11t1, 35t2) is capable of detecting a different incident beam transmitted in one direction different incidence by the window (40fa, 40fb) of the housing (30-31,40-42).   19. Detector according to claim 18, characterized in that the first window (40fa) is arranged just above the first sensor chip (10t, 10t1, 11tl) and the first window (40fa) has an equal or smaller area to a surface of the first sensor chip (10t, 10t1, 11tl), and the second window (40fb) is disposed just above the second sensor chip (10t, 10t2, 11t2) and the second window ( 40fb) has an area equal to or smaller than a surface area of the second sensor chip (10t, 10t2, 11t2).   20. A detector according to claim 19, characterized in that the first window (40fa) is parallel to the first sensor chip (10t, 10tl, 11t1), and the second window (40fb) is parallel to the second sensor (10t, 10t2, 11t2).   21. Detector according to claim 19, characterized in that the first window (40fa) and the first sensor chip (10t, 10t1rlltl) are between them a predetermined angle, and the second window (40fb) and the second sensor chip ( 10t, 10t2, 11t2) form between them another predetermined angle.