JP2015083995A - Infrared sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an infrared sensor which: has compact, thin and simple element geometry; and stably detects temperature of a measurement object even with temperature disturbance caused by external thermal emission (radiation) as well as thermal emission from a heat sensitive element and with temperature distribution at an installation location of a sensor element.SOLUTION: An infrared sensor 10 comprises: a sensor element 1 which detects infrared and outputs an electric signal; a connection terminal 4 to transmit the output of the sensor element to an external device; connection wiring 3 which electrically connects the sensor element and the connection terminal; and a sealing member 5 which seals the sensor element together with the connection terminal as well as the connection wiring except an opening for a light receiving surface. The sealing member has a holding section which holds the sensor element and a field angle restriction window 6 which is extended from the holding section so as to surround a periphery of the light receiving surface and thereby restricting a field range with respect to the infrared incident on the light receiving surface. The field angle restriction window has an inverse tapered shape where a width thereof gradually expands in a direction from an incident position of the infrared to the light receiving surface.

Description

  The present invention relates to an infrared sensor, and more specifically, a compact and thin infrared sensor in which an output of an infrared sensor is not easily affected by disturbance by integrally arranging a viewing angle restricting body on a light receiving surface of the infrared sensor. Related to the prevention of disturbance.

  In general, infrared sensors are used for various applications such as non-contact detection of the surface temperature of an object, detection of the presence of an object, and measurement of gas concentration in the atmosphere. As this infrared sensor, a thermal infrared sensor and a quantum infrared sensor are widely known.

  The thermal infrared sensor detects the electrical properties that are received by infrared rays and heated by the heat and changes as the temperature of the sensor element increases. The sensitivity and response speed are low, but the wavelength band is wide. It can be used at room temperature. There are a thermopile based on the thermoelectromotive force effect, a PZT of a pyroelectric sensor, a thermistor that changes electric resistance due to a temperature change, a bolometer, and the like. When using a thermal infrared sensor, an optical filter that transmits infrared rays is bonded to the opening of the can package for the purpose of blocking heat, and an infrared detection element that detects infrared rays transmitted through the optical filter is canned. A shape that is housed inside the package is used. In addition, as a thermopile sensor, a sensor configured in a mold resin without using a can package has been proposed in order to simplify and improve durability (for example, see Patent Document 1).

  The one described in Patent Document 1 includes a flat plate optical filter that selectively transmits infrared light in a specific wavelength band, and a detection element unit for detecting infrared light transmitted through the optical filter. The infrared detection element formed on the surface, and between the optical filter and the detection element formation surface of the infrared detection element, and adheres the optical filter and the infrared detection element and between the optical filter and the detection element formation surface. And a support for securing a predetermined gap. In other words, the one described in Patent Document 1 is a simplified configuration that does not employ a can package, but has a structure in which an optical filter is provided by securing a predetermined gap on the detection element forming surface of the infrared sensor. It is disclosed that a hollow structure is formed as in the case of using the can package.

  On the other hand, a quantum infrared sensor is a sensor that uses electrons and holes generated by photons when an infrared ray is irradiated on a semiconductor. Photoconductive types (such as HgCdTe) and photovoltaic types (such as InAs) are available. is there. This quantum infrared sensor has the characteristics that the sensitivity depends on the wavelength, has high sensitivity, and has a high response speed, but generally needs to be cooled, and is used together with a cooling mechanism such as a Peltier element or a Stirling cooler. A quantum infrared sensor that can operate at room temperature has also been proposed (see, for example, Patent Document 2).

  The quantum infrared sensor described in Patent Document 2 calculates a compound semiconductor sensor unit that detects an infrared ray by a compound semiconductor layer provided on a substrate and outputs an electric signal, and calculates an electric signal from the compound semiconductor sensor unit. The compound semiconductor sensor unit and the integrated circuit unit are housed in the same package. This makes it less susceptible to electromagnetic noise and thermal fluctuations, enables detection at room temperature, and enables downsizing of the module.

  It is also important to limit the viewing angle of the infrared sensor so that it does not receive infrared rays emitted from objects other than the object to be measured in order to accurately detect the surface temperature without contact using the infrared sensor. It is. As a non-contact temperature sensor having a function of limiting the viewing angle, for example, one disclosed in Patent Document 3 is known.

  The non-contact temperature sensor described in Patent Document 3 has a configuration in which a light guide for limiting the viewing angle is arranged in a housing that attaches and supports an infrared sensor, an optical lens, and a self-temperature sensor. In this non-contact temperature sensor, the optical lens collects infrared rays radiated from the measurement object and sends them to the infrared sensor, and the infrared sensor detects the infrared rays radiated from the measurement object and generates an electrical signal. The self-temperature sensor detects the temperature of the infrared sensor itself for correction. In this non-contact temperature sensor, the light guide functioning as a viewing angle limiting body that limits the viewing angle has a tapered inner diameter that converges on the lens side between the optical lens and the object to be measured. By limiting the viewing angle of the infrared sensor, the sensitivity to the periphery is attenuated and the viewing characteristics are sharpened.

JP 2006-194791 A International Publication No. WO2005 / 027228 Pamphlet Japanese Patent Laid-Open No. 10-227697

  As described above, the viewing angle restricting body can define the viewing range of the infrared sensor by functioning as a viewing angle restricting window that restricts the field of view with respect to the light receiving unit of the infrared sensor. In addition, a configuration as shown in FIG. 1 is generally used. The viewing angle restricting body 17 described in FIG. 1 is provided on the upper surface of the sealing member 15 that seals the infrared sensor so as to surround the light receiving portion 18 of the infrared sensor. The viewing angle restricting body 17 extends vertically upward (in the height direction), and the inner periphery of the upper end functions as a viewing angle restricting window 16, and an angle formed by the viewing angle restricting window 16 and the light receiving surface 18. Defines the visual field range 19 of the infrared sensor.

  By the way, when a viewing angle restricting body is used, a difference in temperature between the viewing angle restricting body and the infrared sensor becomes a measurement error. Therefore, in order to reduce the measurement error and obtain the sensor output stably, it is necessary to reduce the temperature difference or correct the temperature difference.

  In order to solve the problem of measurement error due to this temperature difference, the above-mentioned Patent Document 3 proposes to use a lens and a tapered viewing angle limiter. Other methods include attaching a heater to the viewing angle restriction body to keep the temperature constant, increasing the viewing angle restriction body to increase the heat capacity, and leaving a space between the surrounding area and heat insulation from the surrounding area. Thus, there has been performed a method for correcting the output of the infrared sensor by detecting the temperature of the viewing angle restricting body in a state where the influence of the surrounding temperature change is reduced. However, each method involves a complicated structure and a large size of the viewing angle restricting body. Therefore, there is a problem that the control is complicated and the stability is deteriorated when the ambient temperature changes.

  When a viewing angle restricting body is used for the light receiving portion of the infrared sensor, as shown in FIG. 2, the relative positional deviation between the light receiving window (infrared sensor light receiving portion 18) and the viewing angle restricting body 17 due to the assembly tolerance of the infrared sensor. May occur. For example, in view of design, the viewing angle restricting body 17 should be attached at a position within the viewing range 19a. However, when the sealing is integrally performed, the placement position of the molding die is shifted. When the mounting is performed separately, the bonding position is shifted. Due to the influence of errors that occur during manufacturing, etc., there may be cases where the viewing angle limit is different from the viewing range 19a. For example, when this misalignment position (manufacturing tolerance) is a position shown in the visual field range 19b or the visual field range 19c, the light receiving surface (light receiving unit 18) of the sensor element is covered. Covering the light receiving surface is not preferable because it reduces the light receiving sensitivity of the infrared sensor.

  If the distance between the inner periphery of the viewing angle restricting body 17 and the light receiving surface of the sensor element is smaller than the manufacturing tolerance, even if the viewing angle restricting body itself does not cover the light receiving surface, the light receiving surface is caused by bleeding of an adhesive member or the like. It is possible to adversely affect

  For this reason, in consideration of manufacturing tolerances, it is necessary to use the viewing angle restricting body 17 on the inner periphery having a size sufficiently larger than the size of the light receiving window (light receiving surface 18) of the sensor element. However, when the viewing angle is limited by the viewing angle restricting body 17 having a sufficiently large size on the inner periphery, the height must be sufficiently large. As shown in FIG. 3, in order to give the same viewing angle restriction to the light receiving surface, the larger the inner peripheral dimension of the viewing angle restricting body, the higher the viewing angle restricting window (of the viewing angle restricting body). This is because it is necessary to provide an inner periphery at the upper end. Therefore, when downsizing, there is a problem that high processing accuracy is required at the time of assembly.

  The present invention has been made in view of such problems, and the object of the present invention is to have a small, thin and simple element shape, heat radiation (radiation) from the outside, and heat from the thermal element itself. An object of the present invention is to provide an infrared sensor capable of stably detecting the temperature of an object to be measured even if there is a temperature disturbance such as radiation or a temperature distribution at a place where a sensor element is installed.

  The present invention has been made to achieve such an object, and one embodiment of the present invention has a light receiving surface for receiving infrared light, and detects the received infrared light and outputs it as an electrical signal. A chip-type quantum infrared sensor element having a photoelectric conversion unit mounted thereon, a connection terminal for outputting an output from the quantum infrared sensor element to an external device, the quantum infrared sensor element, and the connection terminal. An infrared sensor comprising a connection wiring for electrical connection, wherein the quantum infrared sensor element is sealed together with the connection terminal and the connection wiring in a state where the light receiving surface is opened. And a viewing angle limiter that surrounds the periphery of the light receiving surface and extends from the holding portion and limits the field of view of the light receiving surface with respect to infrared rays, The field angle restricting portion is formed in a reverse taper shape that becomes wider from the infrared entrance position toward the light receiving surface, and the connection wiring is connected to a surface opposite to the light receiving surface of the quantum infrared sensor element. The viewing angle limiting part is an sealing resin, and is an infrared sensor.

  According to another aspect of the present invention, in the infrared sensor described above, an optical adjustment unit for preventing reflection of an infrared ray or limiting a band on the light receiving surface of the quantum infrared sensor element is provided on the light receiving surface of the quantum infrared sensor element. It is characterized by being.

  Another aspect of the present invention is characterized in that in the above-described infrared sensor, the holding portion and the viewing angle limiting portion are integrally formed.

  Another aspect of the present invention is the above infrared sensor, further comprising an adhesive layer that adheres the viewing angle limiting portion to the holding portion.

  Another aspect of the present invention is the above infrared sensor, wherein the connection wiring is wire bonding.

  According to another aspect of the present invention, in the above infrared sensor, the connection wiring is a flip chip bond.

  According to the present invention, the viewing angle restricting body is provided in close proximity within the same structure as the sensor element constituting the infrared sensor, and the shape of the viewing angle restricting body is inversely tapered. The temperature difference between the infrared sensor and the viewing angle restricting body can be reduced, and an infrared sensor having a small size and high stability can be configured.

It is sectional drawing for demonstrating the visual field of an infrared sensor. It is sectional drawing for demonstrating the conventional viewing angle limit body shift | offset | difference. It is sectional drawing for demonstrating the height of the viewing angle restriction body when the conventional viewing angle restriction body deviation is considered. It is sectional drawing for demonstrating 1st Embodiment of the infrared sensor which concerns on this invention. It is sectional drawing for demonstrating the visual field of the infrared sensor which concerns on this invention. It is sectional drawing for demonstrating the visual field of the infrared sensor which concerns on this invention. It is sectional drawing for demonstrating 2nd Embodiment of the infrared sensor which concerns on this invention. It is sectional drawing for demonstrating 3rd Embodiment of the infrared sensor which concerns on this invention. It is sectional drawing for demonstrating 4th Embodiment of the infrared sensor which concerns on this invention.

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

(First embodiment)
FIG. 4 is a configuration diagram for explaining the first embodiment of the infrared sensor according to the present invention. In FIG. 4, the infrared sensor 10 includes an infrared sensor element 1, an optical adjustment unit 2, a connection wiring 3, a package connection terminal 4, a package sealing member 5, and a viewing angle restriction window 6. Yes.

  In the infrared sensor 10 of the present embodiment, the infrared sensor element 1 for detecting infrared rays and the optical adjustment unit 2 arranged on the light receiving side of the infrared sensor element 1 are in a state where the light receiving surface of the infrared sensor element 1 is opened. It is sealed by the sealing member 5. The sealing member 5 can block infrared light. For example, a general resin for sealing electronic parts such as an epoxy resin, a silicon resin, and a hot melt resin can be used. In addition, a plurality of connection terminals 4 are arranged around the infrared sensor element 1 and are connected to the infrared sensor element 1 by connection wires 3 formed by a plurality of wire bondings, and these are also sealed by the sealing member 5. ing. In addition, a viewing angle limiting window 6 is formed in the sealing member 5, and infrared rays are introduced into the optical adjustment unit 2.

  The optical adjustment unit 2 is an antireflection filter and prevents reflection of infrared rays on the light receiving surface of the infrared sensor element 1. The infrared sensor element 1 receives the infrared light transmitted through the optical adjustment unit 2, detects the infrared light, and outputs an electrical signal. The electrical signal output from the infrared sensor element 1 is output to the connection terminal 4 via the connection wiring 3. The connection terminal 4 is electrically connected to an external device, and outputs an output signal from the infrared sensor element 1 to the external device.

  Since the infrared sensor element 1 is in direct contact with the sealing member 5, it is desirable that the sensor element is provided on the back surface of the substrate (surface opposite to the optical adjustment unit 2). Specifically, a chip-type infrared sensor element in which a photoelectric conversion unit is mounted on the infrared sensor element 1 substrate can be used. As such a chip-type infrared sensor element, a quantum-type infrared sensor having a function of directly converting infrared light into an electrical signal can be considered, but is not limited thereto. In the case of an infrared sensor element that can be configured in a chip type, a similar configuration may be used for a so-called thermal sensor such as a thermopile using MEMS technology that has a function of converting infrared light into heat and then converting it into an electrical signal. it can. The optical adjustment unit 2 may be an optical filter such as LPF or BPF, or may be an optical filter such as LPF or BPF manufactured using a Si substrate or a sapphire substrate. In the case of the optical filter manufactured using a Si substrate, a sapphire substrate, or the like, a structure held by the sealing member 5 may be used.

  In view of its function, the sealing member 5 is formed so as to surround the light receiving surface and to hold the infrared sensor element 1 and to extend from the holding portion so as to surround the light receiving surface. It is divided into a viewing angle restricting portion that restricts the angle).

  Here, in the infrared sensor 10 of the present invention, the configuration of the viewing angle limiting unit that limits the viewing angle to the light receiving surface of the infrared sensor element 1 will be described. 5 and 6 are cross-sectional views for explaining the field of view of the infrared sensor 10 according to the present invention. 5 and 6, a package sealing portion 5a, a viewing angle limiting body 7, a light receiving portion 8, and a viewing range 9 (9a, 9b, 9c) are shown. 5 and 6, the portions other than the light receiving surface 8 of the sensor element 1 are omitted so as to clarify the relationship between the light receiving surface 8 of the sensor element 1 and the viewing angle limiting unit 7.

  The viewing angle restricting body 7 is a structural part for forming a viewing angle restricting window 6 (inner peripheral part at the upper end of each restricting part of the viewing field) in the sealing member 5, and is formed integrally with the sealing part 5a in this embodiment. Has been. The light receiving portion 8 is a light receiving window portion of the infrared sensor element 1. The visual field range 9 is a visual field range of the infrared sensor determined by the light receiving unit 8 and the viewing angle restricting body 7.

  In the infrared sensor 10 of the present invention, as shown in FIGS. 5 and 6, the viewing angle restricting portion (viewing angle restricting body) 7 is formed to have an inversely tapered shape that becomes wider toward the light receiving portion 8. As is apparent from FIG. 6, the visual field range 9 in which the light receiving unit 8 can receive infrared rays is determined by the angle formed by the light receiving unit 8 and the viewing angle limiting window 6 at the upper end (narrowest portion) of the viewing angle limiting body 7. . In the infrared sensor of the present invention, since the viewing angle restricting body 7 is formed in a reverse taper shape, the viewing angle is limited regardless of the size of the viewing angle restricting window 6 at the boundary portion between the sealing portion 5a and the viewing angle restricting body 7. The size of the viewing angle limiting window 6 at the upper end of the limiting body 7 can be configured to be small. As a result, the upper end of the viewing angle restricting body 7 can be formed at a position close to the light receiving unit 8.

  The size of the narrowest viewing angle limiting window 6 on the upper part of the reverse taper may be defined by determining the target viewing range 9 and the height of the viewing angle limiting body 7. There is no need to take into account manufacturing tolerances such as misalignment width. That is, even if these manufacturing tolerances exist, it is not necessary to increase the size of the viewing angle limiting window 6 at the upper end of the viewing angle limiting body 7. This is because, in order to absorb the manufacturing tolerance, it is sufficient that the size of the widest portion (the boundary portion between the viewing angle limiter 7 and the sealing member 5 in the drawing) below the reverse taper is sufficiently large. In addition, since the size of the viewing angle limiting window 6 that is the narrowest portion of the upper portion of the reverse taper is not widened, the upper end position (maximum position) of the viewing angle limiting body 7 as in the conventional viewing angle limiting bodies 17a to 17c (see FIG. 3). It is not necessary to increase the position of the narrow viewing angle restriction window 6. Further, the shape of the viewing angle limiting window 6 as viewed from above (in plan view) may be square or round, but is preferably round from the viewpoint of ease of processing.

  The dimension of the widest part below the reverse taper may be defined wider than the dimension obtained by adding the positional deviation width of the light receiving unit 8 and the viewing angle restricting body 7 to the light receiving surface area of the light receiving unit 6. FIG. 6 is a cross-sectional view for explaining the displacement of the viewing angle restricting body 7 of the infrared sensor according to the present invention. As shown in FIG. 6, even if the light receiving unit 8 and the viewing angle restricting body 7 are displaced relatively from the visual field range 9a to the visual field range 9b or the visual field range 9c, Since the dimension of the part is defined wider than the positional deviation width, the sensor sensitivity is not lowered without blocking the light receiving surface of the light receiving part 8.

  As described above, according to the configuration of the present embodiment, the viewing angle restricting body can be made smaller and thinner than the conventional infrared sensor provided with the viewing angle restricting body integrally, whereby the infrared sensor and the viewing angle restricting body can be reduced. Therefore, a small and thin infrared sensor with high stability can be configured.

(Second Embodiment)
FIG. 7 is a diagram showing this embodiment of the infrared sensor 20 according to the present invention. In this embodiment, the viewing angle limiting portion formed as a part of the sealing member in the first embodiment is formed separately from the sealing portion, and these are bonded together via the adhesive layer 11 or the like. The sealing member is used.

  In the infrared sensor 20 of this embodiment, since the adhesive layer 11 is provided between the sealing portion 5a and the viewing angle restricting portion 7, it is necessary to consider it as a manufacturing tolerance such as a spread width of an adhesive member or the like. In addition, the adhesion method in the contact bonding layer 11 can also be bonded together by an ultrasonic wave, heating, etc. other than the method using an adhesive agent. When pasted together by ultrasonic waves or heating, the spread width of the adhesive member need not be considered.

  Therefore, according to the configuration of the present embodiment, even in the case of an infrared sensor in which a sealing portion and a viewing angle limiting portion are bonded to form a sealing member, the viewing angle limiting body can be made smaller and thinner than conventional ones. Since the temperature difference between the sensor and the viewing angle restricting body is reduced, a small and thin infrared sensor with high stability can be configured.

(Third embodiment)
FIG. 8 is a configuration diagram for explaining a third embodiment of the infrared sensor according to the present invention. In this embodiment, the wire bonding is adopted as the connection wiring between the sensor element and the connection terminal in the first embodiment, whereas the flip chip bond is adopted as the connection wiring between the sensor element and the connection terminal. is there.

  According to the configuration of the present embodiment, as shown in FIG. 8, the space required for connecting the infrared sensor element 1 and the connection terminal 4 can be reduced as compared with the configuration of the first embodiment. Therefore, since the small infrared sensor 30 having a narrow package width can be configured as compared with the first embodiment, the infrared sensor integrally provided with the viewing angle limiter is small and thin, and has a higher stability. can do.

(Fourth embodiment)
FIG. 9 is a configuration diagram for explaining a fourth embodiment of an infrared sensor according to the present invention. In this embodiment, the viewing angle limiting portion formed as a part of the sealing member in the third embodiment is formed separately from the sealing portion, and is bonded and sealed via the adhesive layer 11 or the like. The structure is a stop member.

  In the infrared sensor 40 of this embodiment, since the adhesive layer 11 is provided between the sealing portion 5 and the viewing angle limiting portion 7, it is necessary to consider manufacturing tolerances such as a spread width of an adhesive member or the like. In addition, the adhesion method in the contact bonding layer 11 can also be bonded together with an ultrasonic wave other than the method using an adhesive agent. When pasted by ultrasonic waves, the spread width of the adhesive member need not be considered.

  According to the configuration of the present embodiment, as shown in FIG. 9, the space required for connecting the infrared sensor element 1 and the connection terminal 4 can be reduced as compared with the configuration of the second embodiment. Therefore, since the small infrared sensor 40 having a narrower package width than that of the second embodiment can be configured, the infrared sensor formed by bonding the sealing member and the viewing angle restricting body is small, thin and stable. Higher configuration.

DESCRIPTION OF SYMBOLS 1 Sensor element 2 Optical adjustment part 3 Connection wiring 4 Connection terminal 5 Sealing member 5a Sealing part 6 View angle limit window 7, 7a-7c View angle limit body (view angle limit part)
8 Light-receiving part 9, 9a to 9c Field of view 11 Adhesive layer
10, 20, 30, 40 Infrared sensor

Claims (6)

A chip-type quantum infrared sensor element having a light-receiving surface for receiving infrared light, detecting the received infrared light and outputting it as an electrical signal, having a photoelectric conversion unit mounted on a substrate;
A connection terminal for outputting an output from the quantum infrared sensor element to an external device;
Connection wiring for electrically connecting the quantum infrared sensor element and the connection terminal;
An infrared sensor comprising:
The quantum infrared sensor element is sealed together with the connection terminal and the connection wiring in a state where the light receiving surface is opened, and a holding unit that holds the quantum infrared sensor element, and surrounds the periphery of the light receiving surface. And a viewing angle limiting part that limits the viewing range of the light receiving surface with respect to infrared light, and the viewing angle limiting part is a reverse that becomes wider from the infrared light entrance position toward the light receiving surface. It is formed in a taper shape,
The connection wiring is connected to a surface opposite to the light receiving surface of the quantum infrared sensor element, and the viewing angle limiting portion is a sealing resin.   2. The optical adjustment unit for preventing reflection of infrared rays and limiting a band on the light receiving surface of the quantum infrared sensor element is provided on the light receiving surface of the quantum infrared sensor element. Infrared sensor.   The infrared sensor according to claim 1, wherein the holding portion and the viewing angle limiting portion are integrally formed.   The infrared sensor according to claim 1, further comprising an adhesive layer that adheres the viewing angle restriction portion to the holding portion.   The infrared sensor according to claim 1, wherein the connection wiring is wire bonding.   The infrared sensor according to claim 1, wherein the connection wiring is a flip chip bond.

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