JP2014081204A - Infrared sensor device and far or near determination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an infrared sensor device capable of performing far or near determination in a proximity distance even if an opening of a visual field restriction part is narrowed.SOLUTION: An infrared sensor device includes: an infrared sensor element 310 having a photoelectric conversion unit; an opening 321; and a visual field restriction part 320 covering a portion of a visual field of the infrared sensor element. One portion of a surface forming the opening 321 in the visual field restriction part 320 is covered with a reflection film 322 having higher reflectance than that of the other surface of the visual field restriction part 320. Also, of the surface forming the opening 321 in the visual field restriction part 320, the surface on the side of an external space is configured so as not to be covered with the reflection film 322 having the higher reflectance.

Description

  The present invention relates to an infrared sensor device and a perspective determination device, and more specifically, an infrared sensor device including an infrared sensor element including a photoelectric conversion unit and a visual field limiting unit that covers a part of the visual field of the infrared sensor element. And a perspective determination device.

In general, an infrared sensor is used to receive light in the infrared region (infrared IR: Infrared Ray), convert it into an electrical signal, and extract it as necessary information. For example, since an object emits infrared rays corresponding to its temperature, the infrared sensor device is also used as a means for measuring the temperature of a desired part in a non-contact manner.
This type of infrared sensor device converts the difference between the infrared ray radiated from the desired part according to the temperature and the infrared ray at the temperature of the infrared sensor device itself into an electrical signal with the sensitivity of the infrared sensor, and outputs it. The temperature of a desired part is calculated from the output value, sensitivity, and temperature of the infrared sensor device. In such an infrared sensor device that measures temperature in a non-contact manner, in order to accurately measure the temperature of a desired part, the temperature of the infrared sensor is accurately measured, and a viewing angle limiter is provided to provide a temperature other than the desired part. The surrounding infrared rays are cut. As an infrared sensor device provided with such a field-of-view restriction body, for example, an optical device (infrared sensor device) as described in Patent Document 1 is known.

  FIG. 1 is a cross-sectional configuration diagram of a conventional infrared sensor device including a field-of-view restriction unit disclosed in Patent Document 1. In this optical device, which is an infrared sensor device, the substrate 12 and the signal processing circuit 15 constituting the sensor element are made to be resin-sealed by the sealing member 13 with the opening 14 left, so that the light enters the substrate 12. The light field of view is limited to the opening 14 only. The optical device also includes a substrate 12 on which an optical adjustment unit 11 that transmits only infrared light out of light incident from the opening 14 and a photoelectric conversion unit 10 that photoelectrically converts the transmitted infrared light. ing. The photoelectrically converted signal is further subjected to signal processing by a signal processing circuit unit 15 electrically connected to the photoelectric conversion unit 10.

  Furthermore, in this optical device, from the viewpoint of preventing the substrate 62 on which the photoelectric conversion unit 10 is mounted and the signal processing circuit unit 15 from affecting each other, a metal is disposed on the interposer 17 stacked on the wiring terminals. A substrate 12 and a signal processing circuit unit 15 are provided via bumps 16 and the like. In other words, the photoelectric conversion unit 10 and the signal processing circuit unit 15 are arranged on the interposer 17 at positions where they do not affect each other (is difficult to apply). The temperature of the photoelectric conversion unit 10 is stabilized to obtain a desired signal accuracy.

  Thus, in an infrared sensor device having a field-of-view restriction part, the size of the viewing angle is determined by the inner diameter of the opening part, the thickness of the opening part, and the distance between the opening part and the infrared detection part. It has been known that infrared rays from a narrower detection target range can be accurately quantified by reducing the inner diameter, increasing the thickness of the opening, and increasing the distance between the opening and the infrared detection unit.

  Further, for example, the infrared sensor described in Patent Document 2 has a disturbance infrared ray by reducing the temperature difference between the infrared detection element and the infrared detection element because the distance between the infrared detection element and the part other than the infrared introduction window is short. In order to reduce the error caused by the above, the infrared emissivity is made higher than the inner surface of the waveguide by applying a highly light-absorbing paint on the inner surface of the infrared introduction window (through hole). The viewing angle can be controlled by the infrared introduction window.

International Publication 2006/095834 Pamphlet JP 2001-159666 A

  In an electronic device (for example, a mobile phone, a smart phone, a liquid crystal display, etc.) on which the infrared sensor device as described above is mounted, aesthetics on the appearance are regarded as important. In an infrared sensor device mounted on the surface of this type of electronic device, there is an increasing demand for using a field-limiting part having an extremely small opening so that the field-limiting part is not conspicuous. Moreover, the request | requirement of using the visual field restriction | limiting part of a small opening part is encouraged also from a viewpoint of dustproof or waterproofness.

However, if the opening of the field-of-view restricting portion is small, the field of view when viewed from the infrared sensor element is in a very narrow range, so how close the measurement object is when the measurement object is in the vicinity of the infrared sensor. It becomes impossible to quantify whether or not it exists.
FIGS. 2A and 2B are schematic diagrams when a human hand as a measurement object is moved up and down on an infrared sensor element in an electronic apparatus including an infrared sensor device including a field-of-view restriction unit. It is a figure which shows the operation | movement of the perspective determination by the conventional infrared sensor apparatus. FIG. 2A shows the case of a field limiting part with a narrow opening, and FIG. 2B shows the case of a field limiting part with a wide opening.

  As shown in FIG. 2A, in an electronic device including an infrared sensor device including a field-of-view restriction unit 22 having a narrow opening, when a human hand as a measurement object is moved up and down on the infrared sensor element 21 In addition, regardless of whether the hand is at the upper position 230a or the lower position 230b, the entire visual field of the infrared sensor element is covered with the hand, so the output does not change regardless of the position. Therefore, it is understood that the perspective determination is not realized. That is, in the conventional infrared sensor device, it is understood that perspective determination is difficult in a region where the distance between the infrared sensor device and the measurement object as shown in FIG.

As a means for solving this problem, as shown in FIG. 2B, it is conceivable to widen the opening relative to the area of the light receiving portion of the infrared sensor element. There is a problem that the property is impaired, and the dustproofness and waterproofness are deteriorated.
Further, Patent Document 2 described above discloses that, in the inner surface of the cap, a region having a high infrared emissivity is provided in the vicinity of the infrared detection element, and a region having a low infrared emissivity is provided otherwise. In the invention of this Patent Document 2, a region having a high infrared emissivity functions as the visual field limiter shown in FIG. 2, and a waveguide made of a material having a low infrared emissivity on the extension of the region having a high infrared emissivity. Is provided to increase the distance between the infrared detection element and the measurement object (the distance between the infrared sensor module and the measurement object is reduced). When the infrared sensor disclosed in Patent Document 2 is applied as an infrared sensor used in an electronic device such as a mobile phone, the waveguide protrudes from the surface of the electronic device, and the aesthetics and functionality are impaired. The thickness of the sensor becomes large, causing a mounting problem.

Moreover, since the form currently disclosed as an Example of patent document 2 makes all the vicinity of an infrared detection element the area | region with a high infrared emissivity, the temperature difference of an infrared sensor and the area | region where the infrared emissivity of a waveguide is high Even if it is slight, it greatly affects the output of the sensor, which causes a problem that the detection error increases when the ambient temperature changes. Here, it goes without saying that the closer the distance to the infrared sensor, the larger the area covering the field of view of the sensor, and the greater the influence of the infrared radiation.
The present invention has been made in view of such a situation, and the object of the present invention is to provide an infrared sensor device having a narrow field-of-view restriction with an opening having a narrow field-of-view restriction. An object of the present invention is to provide an infrared sensor device and a perspective determination device capable of performing perspective determination at a close distance.

The present invention has been made to achieve such an object. The invention according to claim 1 has an infrared sensor element (310) having a photoelectric conversion portion, an opening portion (321), and In the infrared sensor device comprising a field-of-view restriction part (320) covering a part of the field of view of the infrared sensor element, a part of the surface forming the opening (321) of the field-of-view restriction part (320) is The field-of-view restriction part (320) is covered with a reflection film (322) having a higher reflectance than the other surface.
According to a second aspect of the present invention, in the first aspect of the invention, the surface on the external space side of the surface forming the opening (321) of the visual field limiting portion (320) has a high reflectance. It is not covered with a reflective film (322).
According to a third aspect of the present invention, in the invention of the first or second aspect, the area of the opening (321) of the visual field restricting part (320) is larger than the area of the infrared sensor element (310). It is characterized by being smaller.

The invention according to claim 4 is the invention according to claim 1, 2, or 3, wherein the area of the opening (321) of the field-of-view restriction part (320) is 0.04 mm ² or more and 100 mm ² or less. It is characterized by being.
The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the height of the opening (321) of the visual field limiting portion (320) is 1 mm or more and 1000 mm or less. It is characterized by.
The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the area of the light receiving portion of the infrared sensor element (310) is 0.2 mm ² or more and 10 mm ² or less. It is characterized by.
The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the infrared sensor element (310) is a quantum infrared sensor.
The invention according to claim 8 is a perspective determination device including the infrared sensor device according to any one of claims 1 to 7.

  According to the present invention, a part of the surface that forms the opening of the field limiting unit is covered with a material having a higher reflectance than the other surface of the field limiting unit, so the opening of the field limiting unit is narrow. However, it is possible to provide an infrared sensor device capable of performing perspective determination at a close distance.

It is a cross-sectional block diagram of the conventional infrared sensor apparatus provided with the visual field restriction | limiting part currently disclosed by patent document 1. FIG. (A), (b) is a schematic diagram when the human hand which is a measuring object is moved up and down on an infrared sensor element in an electronic device including an infrared sensor device including a visual field restriction unit. It is a section lineblock diagram for explaining Example 1 of an infrared sensor device concerning the present invention. It is a figure which shows the relationship of the output of the infrared sensor element in the position of a hand. It is a cross-sectional block diagram for demonstrating Example 2 of the infrared sensor apparatus which concerns on this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a cross-sectional configuration diagram for explaining the infrared sensor device according to the first embodiment of the present invention, in which reference numeral 310 denotes an infrared sensor element, 311 denotes a substrate of the infrared sensor element, 320 denotes a field-of-view restriction unit, and 321 denotes Openings, 322 are reflective films, and 330a, 330b are hands of the measurement object.
The infrared sensor device according to the first embodiment includes an infrared sensor element 310 having a photoelectric conversion unit, and an infrared field detector 320 having an opening 321 and covering a part of the field of view of the infrared sensor element. It is a sensor device. A part of the surface forming the opening 321 of the field limiting unit 320 is covered with a reflective film 322 having a higher reflectance than the other surface of the field limiting unit 320.

In addition, the surface on the outer space side of the surface that forms the opening 321 of the visual field limiting unit 320 is not covered with the reflective film 322 having a high reflectance.
Thereby, in order to improve the aesthetics on an electronic device, dustproofness, and waterproofness, even when an opening part is made small, a required visual field range can be obtained. Here, the field-of-view restriction part that has an opening and covers a part of the field of view of the infrared sensor element may be disposed in the vicinity of the infrared sensor element, or may be disposed at a predetermined distance from the infrared sensor element. May be. Further, the housing may be used as the visual field limiting unit by providing an opening in the housing of the electronic device in which the infrared sensor device of the present invention is mounted.

  2A, when the entire surface of the field limiting portion is covered with a material having a low reflectance, the field viewed from the infrared sensor element 21 is as shown in FIG. ), (B). Accordingly, the same output can be obtained because the hand covers all the fields of view of the infrared sensor element 21 regardless of whether the hand is at the position 230a or 230b. Therefore, it cannot be distinguished whether the hand is at the position 230a or 230b.

However, in the infrared sensor device according to the first embodiment, a part of the surface forming the opening 321 of the visual field limiting unit 320 is covered with the reflective film 322, so that not only the region of the dashed line 340 in FIG. Infrared rays from within the region indicated by the dotted line also reach the infrared sensor element 310, so that the substantial visual field is a region surrounded by the dotted line 350.
Therefore, when the hand is at the position of 330a, in addition to the infrared rays emitted from the hand, the infrared rays from the background not covered by the hand also reach the infrared sensor element. Further, when the hand is at the position of 330b, since the hand covers the entire visual field, infrared rays from the background do not reach the infrared sensor element.

FIG. 4 is a diagram showing the relationship of the output of the infrared sensor element at the hand position. When the background temperature is 20 ° C. and the hand temperature is 33 ° C., the hand is inserted at the position of 330a. Then, it is a figure which shows the output of an infrared sensor element when it closely approaches to the position of 330b after that.
When the hand is inserted at the position of 330a, the hand covers a part of the field of view, so the output when the hand does not cover the field of view at all (output when looking at the background temperature of 20 ° C) A slightly higher output (output between 20 ° C. and 33 ° C.) is obtained. As the hand approaches the infrared sensor device, the output increases. When the hand reaches the position 330b that covers the entire field of view of the infrared sensor element, it receives all infrared rays emitted from the hand and sees an object at 33 ° C. Output is obtained.

  That is, based on the output from the infrared sensor device, it is understood that the proximity determination of the proximity distance is possible even with an infrared sensor device including a field-of-view restricting portion having a narrow opening. By using this output, it is possible to control the linear variables of the mounted electronic device. For example, it is possible to perform control such as volume adjustment, reproduction speed modulation, and enlargement / reduction of the display image in a non-contact manner. .

  In Example 1 shown in FIG. 3, a case where a part of the surface forming the opening 321 of the field limiting unit 320 is covered with a reflective film 322 having a higher reflectance than the other surface of the field limiting unit. Although illustrated, all the surfaces forming the opening 321 of the field limiting unit 320 may be covered with the reflective film 322 having a higher reflectance than the other surfaces of the field limiting unit. In that case, the viewing angle is 180 degrees. That is, it is understood that the coverage of the reflective film 322 may be designed according to a desired viewing angle.

Further, in the above-described first embodiment, the case where the opening 321 is hollow is illustrated, but a window material such as an optical filter that transmits / blocks a specific wavelength may be provided as necessary.
In addition, it is desirable that the area of the opening 321 of the visual field limiting unit 320 is smaller than the area of the infrared sensor element 310. Thereby, an opening part becomes smaller and it can improve the aesthetics on an electronic device, dustproofness, and waterproofness.

In addition, the area of the opening 321 of the visual field limiting unit 320 is preferably 0.04 mm ² or more and 100 mm ² or less. Here, when the mounting position shift is taken into consideration, the opening area is required to be 0.04 mm ² or more. Furthermore, it is calculated | required that it is 100 mm < ² > or less from viewpoints, such as aesthetics on an electronic device.
In addition, the height of the opening 321 of the field-of-view restriction part 320 is desirably 1 mm or more and 1000 mm or less. Here, the height of the opening of the viewing angle restriction unit refers to the distance from the light receiving surface of the infrared sensor element to the upper surface of the opening of the viewing angle restriction unit. For example, when the housing is used as a field-of-view restricting unit by providing an opening in the housing of an electronic device in which the infrared sensor device of the present invention is mounted, the light receiving surface of the infrared sensor element to the outside of the housing is used. Distance.

In general, when performing perspective determination of a heat source of a size such as a hand, the viewing angle is preferably ± 20 ° or more. For example, when the height of the field-limiting body is 1 mm, for example, the photosensitive part of the infrared sensor element When the size is 0.4 mm ² and the opening is 0.2 mm ² (opening area is 0.04 mm ² ), the viewing angle is about ± 10 °, and the linear distance from the infrared sensor element is 30 cm and 10 cm ^2. Since only a narrow range can be observed, it is necessary to expand the apparent field of view using the technique of the present invention.

In addition, when the distance from the infrared sensor element to the heat source to be observed is 1000 mm or more, it becomes difficult to obtain an output necessary for perspective determination. Therefore, the height of the opening of the visual field limiter is preferably 1000 mm or less.
In addition, the area of the light receiving portion of the infrared sensor element 310 is desirably 0.2 mm ² or more and 10 mm ² or less. In order to obtain a sufficient output for determining the perspective of a heat source such as a hand, the area of the light receiving portion of the infrared sensor needs to be 0.2 mm ² or more, and in order to realize a reduction in size of the infrared sensor device. Needs to be 10 mm ² .

  In addition, the infrared sensor element used in the infrared sensor device of the present invention is not particularly limited as long as it has a photoelectric conversion unit that performs photoelectric conversion according to incident infrared rays. For example, a photodiode or a photoconductor For example, a “quantum sensor” that outputs a signal by photoelectric conversion, a “thermal sensor” that converts a temperature change due to infrared absorption into an electrical signal, such as a thermopile or a pyroelectric sensor, can be used.

  Here, thermopile can be used in the same way as quantum infrared sensors, but thermopile is a sensor that uses the Seebeck effect, so the temperature difference between the hot spot and cold spot (reference point) is sufficient to obtain sufficient output. In order to obtain a large value, it is necessary to take a distance. If a sensor is manufactured in a small area, a sufficient output cannot be obtained. On the other hand, if a necessary signal is obtained, the size increases, and the size does not fit in a small electronic device. Therefore, it is desirable that the infrared sensor included in the infrared detection unit is a quantum infrared sensor.

  The material of the field limiting portion excluding the reflective film used in the infrared sensor device of the present invention is preferably a material having a low infrared transmittance from the viewpoint of efficiently removing ambient light. Examples of the material having low infrared transmittance include metal, plastic, epoxy resin, liquid crystal polymer (LCP), polyphenylene sulfide (PPS) resin, and polyester resin that are surface-treated so as not to reflect infrared rays. This is not the case. The field-of-view restriction unit may serve as a casing for the entire infrared sensor device, or may be a member provided separately from the casing. The opening is not particularly limited as long as it has a shape penetrating in the direction of transmitting infrared rays, and may be any of a circle, an ellipse, a square, a rectangle, and a polygon.

The material of the reflective film is not particularly limited as long as it has a higher reflectance than the material of the visual field limiting portion excluding the reflective film. For example, Al, Cu, Ag, Au, Pt, Ni, Cr, Sn, etc. Is mentioned. It goes without saying that this is not the case.
Thus, according to the infrared sensor device of the present invention, a part of the surface forming the opening of the field limiting unit is covered with a material having a higher reflectance than the other surface of the field limiting unit. Even if the opening of the field-of-view restriction part is narrow, it is possible to realize an infrared sensor device capable of performing perspective determination at a close distance.

FIG. 5 is a cross-sectional configuration diagram for explaining an infrared sensor device according to a second embodiment of the present invention. In FIG. 5, reference numeral 510 denotes an infrared sensor element, 520 denotes a visual field limiter, and 522 denotes a reflective film.
Compared with the infrared sensor device of Example 1 described above, the length of the opening in the vertical direction is longer. When the length of the opening in the vertical direction is long, the field of view of the infrared sensor element becomes a region surrounded by a one-dot broken line 540 and narrows. However, the viewing angle of the infrared sensor element is surrounded by a dotted line 550 as in the first embodiment. It is possible to perform perspective determination at a close distance, which has been difficult with a conventional infrared sensor device that does not include the reflective film 522.

  In addition, the present invention can realize a perspective determination device including the infrared sensor device described in the first and second embodiments. Here, the distance determination device can set a threshold for the output value of the infrared sensor device, for example, and determines whether a heat source such as a human body is approaching or separated from a predetermined distance when the threshold is exceeded. This means an apparatus that can determine whether the heat source is relatively approaching or away from the apparatus based on the output value of the infrared sensor apparatus.

  The present invention relates to an infrared sensor device and a perspective determination device including an infrared sensor element including a photoelectric conversion unit, and a field-of-view restriction unit that covers a part of the field of view of the infrared sensor element. According to the above, it is possible to perform perspective determination at a close distance, and it can be suitably used for an electronic device or the like that is highly demanded to use a field limiting body having a narrow opening.

DESCRIPTION OF SYMBOLS 10 Photoelectric conversion part 11 Optical adjustment part 12 Board | substrate 13 Sealing member 14 Opening part 15 Signal processing circuit part 16 Metal bump 17 Interposer 21 Infrared sensor element 22 Field-of-view restriction part 23 Opening part 310,510 Infrared sensor element 311 Board | substrate 320,520 Field-of-view restriction 321 Opening 322, 522 Reflective film 230, 330 Hand

Claims (8)

In an infrared sensor device having an infrared sensor element having a photoelectric conversion unit, an opening, and a visual field limiting unit that covers a part of the visual field of the infrared sensor element,
An infrared sensor device, wherein a part of a surface forming an opening of the field limiting unit is covered with a reflective film having a higher reflectance than the other surface of the field limiting unit.   2. The infrared sensor device according to claim 1, wherein a surface on an external space side of a surface forming the opening of the visual field limiting portion is not covered with the reflective film having a high reflectance.   3. The infrared sensor device according to claim 1, wherein an area of the opening of the visual field limiting unit is smaller than an area of the infrared sensor element. 4. The infrared sensor device according to claim 1, wherein an area of the opening of the visual field restricting portion is 0.04 mm ² or more and 100 mm ² or less.   5. The infrared sensor device according to claim 1, wherein a height of the opening of the visual field limiting unit is 1 mm or more and 1000 mm or less. 6. The infrared sensor device according to claim 1, wherein an area of a light receiving portion of the infrared sensor element is 0.2 mm ² or more and 10 mm ² or less.   The infrared sensor device according to claim 1, wherein the infrared sensor element is a quantum infrared sensor.   A distance determination device comprising the infrared sensor device according to claim 1.

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