JP2013205228A - Semiconductor sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor sensor having a desired viewing angle characteristic.SOLUTION: A semiconductor sensor includes a viewing angle restriction part (3) having viewing angle adjustment means (4) for adjusting, to a desired value, a viewing angle characteristic (100) representing a relation between an incident angle (θ) to a light beam and an electric signal that is output by detecting the light beam, at an upper part of a light beam detection part (2).

Description

  The present invention relates to a semiconductor sensor, and more particularly to an infrared sensor having a viewing angle limiting unit.

  In recent years, infrared sensors have attracted attention from the viewpoint of energy saving and environmental sensors. Human sensors that detect infrared rays emitted by the human body are installed in lighting and air conditioners, contributing to energy savings. The infrared sensor is also expected as a non-contact type thermometer that quantifies the amount of infrared energy incident from the measurement object and detects the temperature.

  Infrared sensors limit the viewing angle of infrared rays incident on the infrared detector to accurately detect infrared energy incident from the measurement object, and disturbing light such as infrared rays emitted from the background other than the detection object Need to be removed. For this reason, in order to restrict | limit a viewing angle, the viewing angle restriction | limiting part provided with the opening part is arrange | positioned in front of the infrared detection part.

  For example, Patent Document 1 discloses an infrared detector having a viewing angle limiting unit (referred to as “cold shield” in Patent Document 1). This infrared detector has been devised to use a material having a large thermal conductivity so that noise due to thermal radiation from the viewing angle limiting portion is less likely to occur. In this infrared detector, the viewing angle is the inner diameter of the opening with a viewing angle restriction ("opening" in Patent Document 1), the thickness of the opening, and the opening and the infrared detecting section ("Infrared" in Patent Document 1). It is determined by the distance to the sensing element ").

  As described above, in the infrared sensor having the viewing angle limiting portion, the size of the viewing angle is determined by the inner diameter of the opening, the thickness of the opening, and the distance between the opening and the infrared detection portion. Infrared rays from a narrower detection target range can be accurately quantified by reducing the inner diameter of the aperture, increasing the thickness of the aperture, and increasing the distance between the aperture and the infrared detector.

JP-A-9-292276

  However, when a semiconductor sensor, in particular an infrared sensor, is to be mounted on a thin portable terminal or the like, if the viewing angle limiter is arranged in order to obtain desired viewing characteristics, the opening is thick and the opening and the infrared detector There is a problem that the distance becomes long, the thickness of the entire infrared sensor becomes thick, and it is difficult to mount in a narrow space.

  Accordingly, an object of the present invention is to provide an infrared sensor in particular as a thin semiconductor sensor having a desired visual field characteristic.

  The present invention provides a semiconductor sensor having a light beam detection unit that detects a light beam emitted from a measurement object and outputs an electric signal, and has an incident angle with respect to the light beam and the output electric signal above the light beam detection unit. A viewing angle limiter having a viewing angle adjusting means for adjusting a viewing angle characteristic indicating a relationship to a desired value, and the viewing angle adjusting means includes N (N is a positive integer of 1 or more). It is characterized by being configured by (N + 1) or more openings with respect to the light beam detection unit.

  The reflectance of the wall surface located around the opening of the viewing angle limiting unit is 20% or less.

  The reflectance of the wall surface of the viewing angle limiting unit disposed at a position facing the light beam detecting unit is lower than the reflectance of the surface of the viewing angle limiting unit.

  The output voltage output as the electrical signal is reduced to 20% of the maximum output of the viewing angle characteristic when the incident angle is within a range of ± 60 degrees.

  The viewing angle limiting portion has a thickness of 20 μm or less.

  The viewing angle adjusting means further includes a window material that transmits the light beam, and adjusts the viewing angle characteristic to a desired value.

  The window material is formed of a silicon plate, a germanium plate, a sapphire plate, a polyethylene plate, or a chalcogenide glass plate.

  The window material is constituted by an optical filter in which a thin film is laminated on a silicon, germanium, or sapphire substrate.

  The light beam detecting unit is installed on a pedestal of a can package, and the viewing angle limiting unit having the viewing angle adjusting unit is configured as a metal can that seals the upper part of the pedestal.

  A predetermined gap is provided between the detection surface of the light beam detector disposed on the pedestal and the viewing angle adjusting means located above the detection surface.

  The light detection unit is formed of a photodiode having a PIN structure including a light absorption layer and a barrier layer on a compound semiconductor substrate.

  The photodiode having the PIN structure includes an n-type indium antimony (InSb) layer, a p-type InSb layer, the n-type InSb layer, and the p-type InSb on a gallium arsenide (GaAs) substrate as the compound semiconductor substrate. P-type aluminum indium as the barrier layer for preventing leakage of carriers generated between the p-type InSb layer and the i-type InSb layer. It is characterized by comprising a photodiode having a PIN structure in which an antimony (AlInSb) layer is laminated.

The viewing angle limiting unit having at least two openings made of Ni is provided as the viewing angle adjusting means on the photodiode having the PIN structure.
The light ray detection unit is configured as an infrared ray detection unit that detects infrared rays as the light rays.

  The infrared detector is configured as a thermal sensor that converts a temperature change due to infrared absorption into an electrical signal.

  The thermal sensor is a thermopile or pyroelectric sensor.

  The infrared detection unit is configured as a quantum sensor that outputs a signal by photoelectric conversion.

  The quantum sensor is a photodiode or a photoconductor.

  According to the present invention, a visual field for adjusting a viewing angle characteristic indicating a relation between an incident angle (θ) with respect to a light beam and an electric signal output by detecting the light beam to a desired value is provided above the light beam detection unit. Since the viewing angle limiting unit having the angle adjusting unit is provided, as the viewing angle adjusting unit, for example, (N + 1) or more openings with respect to N (N is a positive integer of 1 or more) light beam detection units. By configuring this, it becomes possible to accurately detect the energy of infrared rays incident from the object to be measured, thereby providing a thin infrared sensor having a desired viewing angle characteristic by effectively removing ambient light can do.

It is explanatory drawing which shows the structure of the infrared sensor which is the 1st Embodiment of this invention. In the infrared sensor of FIG. 1, it is explanatory drawing which shows the function in which the infrared rays radiated | emitted from a detection target object and a background are detected. It is explanatory drawing which shows the example from which the reflectance of the wall surface of a viewing angle restriction | limiting part differs as a modification of the infrared sensor of FIG. It is explanatory drawing which shows the structural example of the conventional infrared sensor for comparing with the infrared sensor which concerns on this invention. It is explanatory drawing which shows the structural example of the conventional infrared sensor for comparing with the infrared sensor which concerns on this invention. It is explanatory drawing which shows the structural example of the conventional infrared sensor for comparing with the infrared sensor which concerns on this invention. It is explanatory drawing which shows the structure of the infrared sensor which is the 2nd Embodiment of this invention. It is explanatory drawing which shows the structure of the infrared sensor which is the 3rd Embodiment of this invention. It is explanatory drawing which shows the structure of the infrared sensor which is the 4th Embodiment of this invention. It is explanatory drawing which shows the structure of the infrared sensor which is the 5th Embodiment of this invention. It is explanatory drawing which shows the viewing angle characteristic of the infrared sensor which is the 6th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First example]
A first embodiment of the present invention will be described with reference to FIGS.

  In the present invention, in a semiconductor sensor (1) having a light beam detector (2) that detects a light beam emitted from a measurement object and outputs an electrical signal, an incident angle with respect to the light beam is formed above the light beam detector (2). A viewing angle limiting unit (3) having a viewing angle adjusting means (4) for adjusting a viewing angle characteristic (100) indicating a relationship between (θ) and an output electric signal to a desired value; Features.

  The viewing angle adjusting means (4) is configured by an opening (4) having a predetermined size through which a light beam passes, and the viewing angle characteristic (100) is set to a desired value by setting the opening to a predetermined size. Can be adjusted.

  The viewing angle limiting unit (3) having the viewing angle adjusting means (4) may be manufactured in a series of work steps when the light detection unit (2) is manufactured, or manufactured as a single unit. After that, it may be attached as a separate member on the light detector (2).

  Here, the incident angle (θ) is defined as an axis 60 perpendicular to the detection surface (2a) of the light beam detector (2) as θ = 0 degrees, and the angle at which the light beam is incident on the axis 60. I mean.

<Specific example>
Hereinafter, in this example, an infrared sensor will be described as an example of the semiconductor sensor.

  FIG. 1 shows a configuration example of the infrared sensor 1.

(Constitution)
The infrared sensor 1 includes a resin package 5 serving as a base, an infrared detection unit 2 embedded in the resin package 5, and a viewing angle restriction unit 3 disposed above the infrared detection unit 2. The viewing angle restriction unit 3 is formed with a plurality of openings 4 as viewing angle adjustment means. The plurality of openings 4 are arranged to face each other above the detection surface 2 a of the infrared detection unit 2.

  Reference numeral 41 denotes a wall surface of the viewing angle limiting unit 3 in which the opening 4 is formed. Reference numeral 42 denotes an opening region in which the opening 4 is formed.

  As described above, the infrared sensor 1 includes the infrared detection unit 2 molded by the resin package 5 and the viewing angle limiting unit 3 having the opening 4. In this example, the infrared detection unit 2 is a photodiode having a multilayer semiconductor film, and absorbs infrared rays emitted from a detection target and outputs an electrical signal.

  The infrared detector 2 is not particularly limited as long as it is a sensor that absorbs infrared rays and converts it into an electrical signal. For example, a “quantum sensor” that outputs a signal by photoelectric conversion, such as a photodiode or a photoconductor, a thermopile, A “thermal sensor” that converts a temperature change due to infrared absorption into an electrical signal, such as a pyroelectric sensor, can be used.

  The viewing angle limiting unit 3 has an opening 4 through which at least infrared rays radiated from the detection target are transmitted. The number of the openings 4 is not particularly limited as long as it is larger than the number of the infrared detectors 2 and can remove disturbance light emitted from the background other than the detection target. However, from the viewpoint of reducing the thickness of the viewing angle limiting portion 3, it is preferable that the number of the opening portions 4 is large.

  As a material of the viewing angle limiting unit 3, a material having a low infrared transmittance is preferable from the viewpoint of efficiently removing disturbance light. Examples of the material having a low infrared transmittance include, but are not limited to, metals, epoxy resins, and polyester resins.

  The opening 4 is not particularly limited as long as it has a shape penetrating in the direction of transmitting infrared rays, and may be circular or polygonal. The opening may be a cavity or may be filled with a window material that transmits infrared rays, as shown in an example described later.

  The wall surface 41 of the viewing angle limiting unit 3 that forms the opening 4 preferably has a low reflectance in order to prevent reflection of ambient light. For example, the epoxy resin is preferably black, and the metal is preferably aluminum whose surface is black anodized. Furthermore, as a processing method of the viewing angle limiting unit 3, it is preferable that drawing processing, no-finish processing, and no polishing are performed from the viewpoint of reducing the reflectance. Further, even a material having a high reflectance can be suitably used by applying a black body paint or the like to the wall surface 41 to reduce the reflectance. It is preferable that the reflectance of the wall surface 41 of the viewing angle limiting portion that forms the opening 4 is 20% or less.

  The shape of the opening region 42 having the opening 4 is a configuration in which more light rays radiated from the measurement object reach the infrared detection unit 2 and is parallel to the detection surface 2a from the viewpoint of increasing the sensitivity of the sensor. It is preferable that the ratio of the area of the opening 4 to the area of the opening region 42 in a certain direction is high.

  In FIG. 1, the wall surface 41 is in contact with the infrared detection unit 2. From the viewpoint of efficiently removing disturbance light close to the horizontal direction, the wall surface 41 is preferably disposed at a distance close to each other, and more preferably in contact with each other.

(Feature Description)
FIG. 2 illustrates the function in the case where the detection object and the infrared ray radiated from the background exist in the infrared sensor 1 of the present example.

  Reference numeral 20 denotes a detection target. Reference numeral 21 denotes infrared rays incident from the detection target 20. Reference numeral 22 denotes a background. Reference numeral 23 denotes disturbance light emitted from the background 22.

  As shown in FIG. 2, in the infrared sensor 1, the infrared ray 21 incident from the detection target 20 passes through the opening 4 in the opening region 42 of the viewing angle restriction unit 3 and reaches the infrared detection unit 2. The infrared ray 21 is detected, and this detection signal is converted into an electrical signal and output. On the other hand, the disturbance light 23 radiated from the background 22 is absorbed and removed by the wall surface 41 of the viewing angle restriction unit 3 that forms the opening 4 and is installed immediately above the infrared detection unit 2. It is not detected by the unit 2 and is not output as an electric signal.

<Modification>
FIG. 3 shows a configuration of an infrared sensor 1 which is a modified example of FIGS. 1 and 2.

  Reference numeral 31 denotes a viewing angle limiting portion made of a member having a relatively high reflectance of the surface 31a. Reference numeral 43 denotes a wall surface of the viewing angle limiting unit 31.

  As shown in FIG. 3, when the reflectance of the wall surface 43 of the viewing angle restriction unit 31 is relatively high, the disturbance light 23 radiated from the background 22 is reflected by the wall surface 43 and enters the infrared detection unit 2. However, since the infrared rays radiated from the background 22 in the process of being reflected by the wall surface 43 are attenuated, the infrared rays 21 can be measured within a desired viewing angle with almost no decrease in accuracy.

  Next, Comparative Examples 1 to 3 will be described.

<Comparative Example 1>
FIG. 4 shows Comparative Example 1 for comparison with the infrared sensor 1 of this example.

  11 shows a configuration example of an infrared sensor including the viewing angle limiting unit 3 having the opening 4 having a size corresponding to one opening region 42.

  In the infrared sensor 11, the thickness of the viewing angle restriction unit 3 and the area of the opening region 42 are equal as compared with the infrared sensor 1 of this example. As shown in FIG. 4, when there is only one opening 4, since no wall surface exists on the optical path of the disturbance light 23, the disturbance light 23 reaches the infrared detection unit 2 directly, and the detection target 20 It is impossible to measure the infrared rays incident from the center with high accuracy.

<Comparative example 2>
FIG. 5 shows a comparative example 2 for comparison with the infrared sensor 1 of the present example.

  The infrared sensor 11 has the same viewing angle as that of the infrared sensor 1 of this example, but the area of the plane parallel to the substrate of the opening region 42 is equal, and the viewing angle limiting portion 3 is thick. In this way, when only one opening 4 is present, if the ambient light 23 is removed to obtain the same viewing angle as that of the infrared sensor 1 of this example, a thicker viewing angle limiter 3 is required. It is understood that

<Comparative Example 3>
FIG. 6 shows a comparative example 3 for comparison with the infrared sensor 1 of the present example.

  In the infrared sensor 11, the thickness of the viewing angle restriction portion 3 is equal and the area of the opening region 42 is smaller than that of the infrared sensor 1 of this example. Thus, when there is only one opening 4 and an attempt is made to make the viewing angle limiter 3 thinner, the viewing angle limiter 3 covers most of the infrared detection unit 2, and the sensitivity of the sensor. Will be greatly reduced.

  As described above, in the infrared sensor 1 of the present example, the infrared ray 21 radiated from the detection target object 20 passes through the opening 4 of the viewing angle limiting unit 3 and reaches the infrared detection unit 2, on the other hand, other than the detection target object The disturbance light 23 such as infrared rays radiated from the background 22 is not reflected or absorbed by the viewing angle restriction unit 3 and reaches the infrared detection unit 2, so that a desired viewing angle θ can be obtained. Thus, the infrared sensor 1 can accurately detect the infrared energy incident from the measurement object.

  In addition, by providing a large number of openings 4, the wall surface 41 blocks the optical path of the disturbance light 23 and reduces the disturbance light 23 even if the thickness of the viewing angle limiter 3 is reduced without narrowing the opening region 42. Since it becomes possible to remove, the thin infrared sensor 1 can be produced, without significantly impairing the sensitivity of the infrared sensor 1.

  As described above, in order to adjust the viewing angle characteristic 100 indicating the relationship between the incident angle (θ) with respect to the light beam and the electric signal output by detecting the light beam, to the desired value at the upper portion of the light beam detection unit 2. Since the viewing angle restricting unit 3 having the viewing angle adjusting unit 4 is provided, as the viewing angle adjusting unit 4, for example, (N + 1) for N (N is a positive integer of 1 or more) light beam detecting units 2. ) By configuring more than four openings 4, it is possible to accurately detect the energy of infrared rays incident from the measurement object, thereby effectively removing disturbance light and obtaining a desired viewing angle characteristic. The thin infrared sensor 1 which has can be provided.

[Second example]
A second embodiment of the present invention will be described with reference to FIG. In addition, about the same part as the 1st example mentioned above, the description is abbreviate | omitted and the same code | symbol is attached | subjected.

  FIG. 7 shows a configuration example of the infrared sensor 1 according to the present invention.

  In the infrared sensor 1 of this example, a window material 6 that transmits infrared rays is provided in the region of the opening 4 formed in the viewing angle restriction portion 3.

  The window material 6 is not particularly limited as long as it transmits infrared light having a wavelength that outputs an infrared sensor signal at least when the infrared detection unit 2 receives light.

  As the window material 6, for example, a plate material such as a silicon plate, a germanium plate, a sapphire plate, a polyethylene plate, a chalcogenide glass plate, or an optical filter in which a thin film is laminated on a substrate such as silicon, germanium, or sapphire can be used. .

  Further, as the window member 6, it is also possible to use an optical lens that collects infrared rays.

[Third example]
A third embodiment of the present invention will be described with reference to FIG. In addition, about the same part as each example mentioned above, the description is abbreviate | omitted and the same code | symbol is attached | subjected.

  FIG. 8 shows a configuration example of the infrared sensor 1 according to the present invention.

  In the infrared sensor 1 of this example, an optical filter 7 is provided between the infrared detection unit 2 and the viewing angle restriction unit 3.

  The optical filter 7 is appropriately selected depending on the application of the infrared sensor. For example, a filter that removes infrared rays having a wavelength shorter than 5 μm is preferably used for the purpose of preventing the incidence of sunlight, such as a human sensor or a radiation thermometer, but is not limited thereto.

  In addition to an optical filter, an infrared sensor having a desired viewing angle characteristic can be obtained as long as it is made of a material that transmits infrared rays.

  Further, the optical filter 7 may be disposed on the entire surface of the substrate as shown in FIG. 8, but it may be present at least in a partial region between the infrared detection unit 2 and the opening 4.

  FIG. 8 shows an example in which the infrared detection unit 2, the optical filter 7, and the viewing angle restriction unit 3 are stacked in this order, but the infrared detection unit 2, the viewing angle restriction unit 3, and the optical filter 7 are illustrated. You may comprise as a structure laminated | stacked in this order.

[Fourth example]
A fourth embodiment of the present invention will be described with reference to FIG. In addition, about the same part as each example mentioned above, the description is abbreviate | omitted and the same code | symbol is attached | subjected.

  FIG. 9 shows a configuration example of the infrared sensor 1 according to the present invention.

  The infrared sensor 1 of this example includes two red line detection units 2. Thus, even in the infrared sensor 2 having a plurality of infrared detection units 2, if the number of openings 4 is larger than the number of infrared detection units 2, the wall surface 41 installed immediately above the infrared detection unit 2. Can block the optical path of disturbance light and remove the disturbance light. Thereby, it is possible to make the infrared sensor 1 thinner without narrowing the opening region 42 as compared with the case where the number of the infrared detection units 2 is equal to or more than the number of the openings 4.

[Fifth example]
A fifth embodiment of the present invention will be described with reference to FIG. In addition, about the same part as each example mentioned above, the description is abbreviate | omitted and the same code | symbol is attached | subjected.

  FIG. 10 shows a configuration example of the infrared sensor 1 according to the present invention.

  The infrared sensor 1 of this example is configured by a can package 53 including a metal can 51 and a pedestal 52. On the pedestal 52, the infrared detection unit 2 is installed. In the metal can 51 located above the infrared detection unit 2, an opening 4 as a viewing angle adjusting unit is formed at a position facing the detection surface of the infrared detection unit 2. Thereby, in this example, metal can 51 itself is comprised as a viewing angle restriction | limiting part.

  A gap 54 exists between the opening 4 and the detection surface of the infrared detection unit 2 and is in a non-contact state. Thus, the opening 4 does not necessarily need to be in contact with the infrared detection unit 2, but functions as a viewing angle limiting unit in order to effectively remove disturbance light and effectively obtain a desired viewing angle characteristic. The thickness of the metal can 51 is preferably thicker than the gap 54 between the upper portion of the infrared detecting unit 2 and the metal can 51.

  The infrared sensor 1 of this example can be suitably used when the infrared detection unit 2 is configured as a “thermal sensor” that converts a temperature change due to infrared absorption into an electrical signal, such as a thermopile or a pyroelectric sensor.

  In each of the above examples, the function of the viewing angle limiting unit in the cross-sectional direction has been described by showing a cross-sectional view. However, in the present invention, the same effect can be obtained with the same configuration in the depth direction of the cross-sectional view.

[Sixth example]
A sixth embodiment of the present invention will be described with reference to FIG. In addition, about the same part as each example mentioned above, the description is abbreviate | omitted and the same code | symbol is attached | subjected.

  The configuration of the infrared detection unit 2 in the infrared sensor 1 of this example will be described with reference to FIG.

  The infrared detection unit 2 is configured as a photodiode having a PIN structure including a light absorption layer and a barrier layer on a compound semiconductor substrate.

  A photodiode having a PIN structure has a n-type indium antimony (InSb) layer, a p-type InSb layer, an n-type InSb layer, and a p-type InSb layer on a gallium arsenide (GaAs) substrate as a compound semiconductor substrate. An i-type InSb layer as a light absorption layer, and a p-type aluminum indium antimony (AlInSb) layer as a barrier layer for preventing leakage of carriers generated between the p-type InSb layer and the i-type InSb layer, It is constructed by stacking.

  Further, at least two (for example, 121 may be) openings 4 made of Ni are provided as viewing angle adjusting means on the upper part of the photodiode having the PIN structure of the infrared detecting section 2 configured as described above. A viewing angle restriction unit 3 is provided.

(Measurement example)
In this example, using the infrared sensor 1 shown in FIG. 1 described above, the output signal was measured by changing the incident angle θ of infrared rays, and the viewing angle characteristics were evaluated.

<Viewing angle characteristics>
FIG. 11 is an explanatory diagram showing the viewing angle characteristic 100 of the infrared sensor 1 in this example.

  A black body furnace having an aperture with an inner diameter of 3.2 mm set at 227 ° C. using the infrared sensor 1 is set as a detection object 20. The distance between the infrared sensor 1 and the black body furnace is 100 mm.

  In this way, under the measurement conditions, the infrared ray 21 radiated from the blackbody furnace is detected while changing the incident angle θ within the range of 0 ° to ± 90 °, and the normalized output voltage with respect to the incident angle θ is measured. did.

  As shown by curve A (solid line) in FIG. 11, the output voltage decreases to 20% of the maximum output at an incident angle of θ = ± 60 degrees, and is substantially zero at an incident angle of θ = ± 80 degrees. The viewing angle of the infrared sensor 1 is limited by the viewing angle limiting unit 3 having a thickness of 20 μm. As a result, it is possible to accurately detect infrared energy incident from the detection target 20.

(Comparative example)
As a comparative example, using the infrared sensor 11 shown in FIG. 5, the thickness of the viewing angle restricting portion 3 and the viewing angle characteristics 100 were examined. The infrared sensor 11 to be compared is configured to include a viewing angle restriction unit 3 having one opening 4 for one infrared detection unit 2.

  In order to obtain a viewing angle characteristic of substantially zero at an incident angle of θ = ± 80 degrees using the viewing angle limiting unit 3 having the opening area 42 of the same area for the same infrared detection unit 2 as in the present invention, the viewing angle The limiting portion 3 needs to have a thickness of 150 μm.

  That is, it can be seen that when the viewing angle restriction unit 3 having 121 openings according to the present invention is not provided, the viewing angle restriction unit 3 becomes thick and the infrared sensor becomes thick.

  This invention is mainly related to an infrared sensor such as a photodiode or a thermopile, and has a viewing angle characteristic that can accurately detect infrared energy incident from a measurement object. The thin infrared sensor which has can be provided.

1 Semiconductor sensor (infrared sensor)
2 Light detector (infrared detector)
2a detection surface 3 viewing angle limiter 4 viewing angle adjustment means (opening)
5 Resin package 20 Measurement object (detection object)
21 rays (infrared rays)
22 Background 23 Ambient Light 31 Viewing Angle Limiting Section 31a Surface 41 Wall 42 Opening Area 51 Metal Can 52 Base 53 Can Package 54 Clearance 60 Axis 100 Viewing Angle Characteristics

Claims (18)

In a semiconductor sensor having a light detection unit that detects light emitted from a measurement object and outputs an electrical signal,
A viewing angle limiting unit having a viewing angle adjusting means for adjusting a viewing angle characteristic indicating a relationship between an incident angle with respect to the light beam and the output electric signal to a desired value is provided on the light detecting unit,
2. The semiconductor sensor according to claim 1, wherein the viewing angle adjusting means includes (N + 1) or more openings with respect to N (N is a positive integer of 1 or more) light beam detection units.   The semiconductor sensor according to claim 1, wherein a reflectance of a wall surface located around the opening of the viewing angle limiting portion is 20% or less.   The reflectance of the wall surface of the viewing angle limiting unit disposed at a position facing the light beam detecting unit is lower than the reflectance of the surface of the viewing angle limiting unit. Semiconductor sensor.   4. The output voltage output as the electric signal decreases to 20% of the maximum output of the viewing angle characteristic within the range of the incident angle of ± 60 degrees. 5. Semiconductor sensor.   The semiconductor sensor according to claim 4, wherein the viewing angle limiting portion has a thickness of 20 μm or less.   The semiconductor sensor according to claim 1, wherein the viewing angle adjusting unit further includes a window member that transmits the light beam.   The semiconductor sensor according to claim 6, wherein the window material is formed of a silicon plate, a germanium plate, a sapphire plate, a polyethylene plate, or a chalcogenide glass plate.   7. The semiconductor sensor according to claim 6, wherein the window material is constituted by an optical filter in which a thin film is laminated on a silicon, germanium, or sapphire substrate. The light detection unit is installed on the base of the can package,
9. The semiconductor sensor according to claim 1, wherein the viewing angle limiting unit having the viewing angle adjusting means is configured as a metal can that seals the upper portion of the pedestal.   10. The semiconductor according to claim 9, wherein a predetermined gap is provided between a detection surface of the light beam detection unit disposed on the pedestal and the viewing angle adjustment unit positioned above the detection surface. Sensor.   11. The semiconductor sensor according to claim 1, wherein the light detector includes a photodiode having a PIN structure including a light absorption layer and a barrier layer on a compound semiconductor substrate.   The photodiode having the PIN structure includes an n-type indium antimony (InSb) layer, a p-type InSb layer, the n-type InSb layer, and the p-type InSb on a gallium arsenide (GaAs) substrate as the compound semiconductor substrate. P-type aluminum indium as the barrier layer for preventing leakage of carriers generated between the p-type InSb layer and the i-type InSb layer. 12. The semiconductor sensor according to claim 11, comprising a photodiode having a PIN structure in which an antimony (AlInSb) layer is laminated.   13. The semiconductor sensor according to claim 12, wherein the viewing angle limiting portion having at least two openings made of Ni is provided as the viewing angle adjusting means on an upper portion of the photodiode having the PIN structure.   The semiconductor sensor according to claim 1, wherein the light beam detecting unit is configured as an infrared ray detecting unit that detects infrared light as the light beam.   The semiconductor sensor according to claim 14, wherein the infrared detection unit is configured as a thermal sensor that converts a temperature change due to infrared absorption into an electrical signal.   The semiconductor sensor according to claim 15, wherein the thermal sensor is a thermopile or a pyroelectric sensor.   The semiconductor sensor according to claim 14, wherein the infrared detection unit is configured as a quantum sensor that outputs a signal by photoelectric conversion.   The semiconductor sensor according to claim 17, wherein the quantum sensor is a photodiode or a photoconductor.

Images