JP2018109619A - Light receiving device and light emitting/receiving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly accurate light receiving device and light emitting/receiving device compensated for an influence of temperature and humidity.SOLUTION: A light receiving device 2 comprises: a light receiving element 21 for receiving at least a part of light made incident from the outside, and for outputting an output signal corresponding to an amount of received light; a mold resin part 22 for sealing at least a part of the light receiving element 21; a temperature information acquisition part 23 for acquiring temperature information TI; a humidity information calculation part 24 for calculating humidity information HI on the basis of information on at least one of electric characteristics and optical characteristics of the light receiving element 21 and the temperature information TI; and a compensation part 25 for compensating an output signal SO on the basis of the temperature information TI and the humidity information HI.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light receiving device and a light receiving / emitting device.

  Conventionally, as an application of the optical physical quantity measurement technology using a light receiving device and a light emitting device, a distance measuring sensor for measuring the distance to a detection target and a gas concentration measuring device for measuring the concentration of a measurement target gas in the atmosphere Has been proposed.

  In particular, as a gas concentration measuring device, in the mid-infrared infrared region, utilizing the fact that the absorption wavelength of the gas varies depending on the gas type, non-dispersive infrared absorption that measures the gas concentration by detecting this absorption amount A type (Non-Dispersive Infrared) gas concentration measuring apparatus is known. As a gas concentration measurement device using this principle, for example, by combining a filter (transmission member) that transmits infrared light limited to a wavelength with which the measurement target gas has absorption characteristics and an infrared sensor, the amount of infrared absorption is measured. A gas concentration can be measured (for example, Patent Document 1).

JP-A-9-33431

  When configuring such an optical measurement device, it is necessary to remove the influence of environmental temperature and humidity as much as possible in order to maintain the required accuracy. Conventionally, package technologies such as ceramic packages and can packages have been used. Has been used. On the other hand, the resin mold technology widely used in integrated circuits, etc. is an excellent technology that can be manufactured in large quantities and at low cost, but the resin due to thermal stress and humidity caused by the difference in thermal expansion between the resin material, the light receiving element, and the light emitting element. The amount of light emitted from the light emitting element and the output signal of the light receiving element fluctuate due to the influence of swelling stress caused by moisture absorption or drying. For this reason, the conventional molding technique has a problem that a highly accurate light source, sensor, gas sensor, or the like cannot be realized.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a high-precision light-receiving device and light-receiving / emitting device in which the influence of temperature and humidity is compensated.

  In order to achieve the above object, a light receiving device according to an aspect of the present invention includes a light receiving element that receives at least part of light incident from the outside and outputs an output signal corresponding to the amount of light received, and at least the light receiving element. Humidity information based on the temperature information, a mold resin part that seals a part, a temperature information acquisition part that acquires temperature information, information on at least one of electrical characteristics and optical characteristics of the light receiving element, and the temperature information A humidity information calculation unit for calculating, and a compensation unit for compensating the output signal based on the temperature information and the humidity information are provided.

  In order to achieve the above object, a light receiving and emitting device according to one embodiment of the present invention receives a light emitting element and at least a part of light output from the light emitting element, and outputs an output signal corresponding to the amount of received light. A light receiving element, a mold resin portion that seals at least a part of the light receiving element, a temperature information acquisition unit that acquires temperature information, information on at least one of electrical characteristics and optical characteristics of the light receiving element, and A humidity information calculating unit that calculates humidity information based on the temperature information; and a control unit that controls the light emitting element based on the temperature information and the humidity information.

  According to one embodiment of the present invention, a highly accurate light-receiving device and light-receiving / emitting device in which influences due to temperature and humidity are compensated can be realized.

It is a block diagram for demonstrating the light-receiving device which concerns on 1st Embodiment of this invention. It is a block diagram for demonstrating the light-emitting device which concerns on 2nd Embodiment of this invention. It is a block diagram for demonstrating the light emitting / receiving apparatus which concerns on 3rd Embodiment of this invention. It is a figure explaining the light receiving and emitting apparatus which concerns on the Example of embodiment of this invention, Comprising: The figure which shows the relationship between the carbon dioxide actual concentration at the time of applying a light receiving and emitting apparatus to a carbon dioxide concentration measuring apparatus, and a carbon dioxide concentration calculation value It is. It is a figure which shows the relationship between the carbon dioxide actual concentration in a comparative example, and a carbon dioxide concentration calculation value.

  Hereinafter, modes for carrying out the present invention (hereinafter referred to as the present embodiment) will be described. The following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

<Light receiving device>
The light receiving device according to the present embodiment receives at least a part of light incident from the outside and outputs an output signal corresponding to the amount of received light, and a mold resin portion that seals at least a part of the light receiving element. A temperature information acquisition unit that acquires temperature information, information on at least one of electrical characteristics and optical characteristics of the light receiving element, a humidity information calculation unit that calculates humidity information based on the temperature information, and the temperature information And a compensator for compensating the output signal based on the humidity information.

  According to the light receiving device according to the present embodiment, it becomes possible to compensate for the influence of fluctuations in the output signal of the light receiving element due to temperature and humidity, and realize measurement of optical physical quantities with higher accuracy than in the past. be able to. As an example, by using the light receiving device according to the present embodiment for a non-dispersive infrared absorption type gas concentration measuring device, the amount of infrared absorption by the measurement target gas can be measured with high accuracy, so that the gas concentration measurement accuracy is improved. It becomes possible. Here, light incident from the outside refers to light incident from a light source spatially separated from the light receiving element.

<Light emitting device>
The light-emitting device according to the present embodiment relates to a light-emitting element, a mold resin portion that seals at least a part of the light-emitting element, a temperature information acquisition unit, and at least one of electrical characteristics and optical characteristics of the light-emitting element. A humidity information calculation unit that calculates humidity information based on the information and the temperature information; and a control unit that controls the light emitting element based on the temperature information and the humidity information.

  According to the light emitting device according to the present embodiment, it becomes possible to compensate for the influence of the variation in the light emission amount of the light emitting element due to the temperature and humidity, and realize the measurement of the optical physical quantity with higher accuracy than in the past. be able to. As an example, by using the light emitting device according to the present embodiment for a non-dispersive infrared absorption gas concentration measuring device, it is possible to irradiate the measurement target gas with infrared light with a high accuracy, so that the gas concentration Measurement accuracy can be improved.

<Light emitting / receiving device>
The light emitting / receiving device according to the present embodiment includes a light emitting element, a light receiving element that receives at least part of light output from the light emitting element, and outputs an output signal corresponding to the amount of received light, and at least part of the light emitting element. Humidity information is calculated based on the mold resin portion for sealing, a temperature information acquisition portion for acquiring temperature information, information on at least one of electrical characteristics and optical characteristics of the light emitting element, and the temperature information A humidity information calculating unit that compensates the output signal based on the temperature information and the humidity information.

According to the light emitting / receiving device according to the present embodiment, it becomes possible to compensate for the influence of fluctuations in the output signal of the light receiving element and the light emission amount of the light emitting element due to temperature and humidity, and optical accuracy is higher than in the past. Measurement of physical quantities can be realized. As an example, by using the light emitting and receiving device according to the present embodiment for a non-dispersive infrared absorption type gas concentration measuring device, it is possible to irradiate the measurement target gas with infrared light with a high accuracy, and to measure Since the amount of infrared rays absorbed by the target gas can be measured with high accuracy, the measurement accuracy of the gas concentration can be improved. In addition, by using infrared absorption by impurities in the liquid, it is possible to configure a measuring apparatus that measures the impurity concentration in the liquid with high accuracy.
Hereinafter, each component of the light receiving device, the light emitting device, and the light receiving and emitting device according to the present embodiment will be described with examples.

<Light receiving element>
The light receiving device according to the present embodiment and the light receiving element in the light receiving and emitting device are not particularly limited as long as they have sensitivity in a light band including a wavelength suitable for the intended use. In particular, when the light receiving element is used as a gas concentration measuring device, it is not particularly limited as long as it has sensitivity in the band of light including the wavelength absorbed by the gas to be detected.

  The light receiving element is preferably a thermal sensor such as a pyroelectric sensor, a thermopile, or a bolometer, or a quantum sensor such as a photodiode or a phototransistor. The light receiving element may further include an optical filter having desired optical characteristics in combination with the measurement target gas. For example, when the gas to be detected is carbon dioxide, it is preferable that the light receiving element is equipped with a band-pass filter capable of filtering infrared light in a wavelength band (typically around 4.3 μm) where infrared absorption by carbon dioxide gas is large.

  Further, the inventors of the present invention, when at least a part of the light receiving element is sealed with a mold resin, the stress applied to the light receiving element changes due to the influence of at least one of moisture absorption and drying of the mold resin portion. We have newly discovered that the output of the light receiving element fluctuates. The inventors clearly found that this finding can compensate for the influence of fluctuations in the output signal of the light receiving element due to moisture absorption of the mold resin part by measuring information correlated with the humidity of the mold resin part (humidity information). did.

  As will be described later, the inventors calculate information (humidity information) correlated with the humidity of the mold resin portion based on the temperature information and information on at least one of the electrical characteristics and optical characteristics of the light receiving element. I found something new that I can do. Thus, by measuring information on at least one of the electrical characteristics and optical characteristics of the light receiving element, information (humidity information) correlated with the humidity of the mold resin part is obtained, and the obtained temperature information and humidity information are obtained. It is possible to compensate the output of the light receiving element by using.

In the light receiving device and the light receiving / emitting device according to the present embodiment, the light receiving element includes indium, includes at least one of arsenic and antimony, and has a diode structure including at least a P-type semiconductor layer and an N-type semiconductor layer. Or a resistor. Thus, particularly in the gas concentration measuring device for measuring the concentration of CO _2, it is possible to measure the infrared around 4.3μm, which is an absorption wavelength band of CO ₂ at a high S / N ratio. In the light receiving device and the light receiving and emitting device according to the present embodiment, the light receiving element may include an auxiliary element as will be described later.

<Light emitting element>
The light emitting element in the light emitting device and the light receiving and emitting device according to the present embodiment is not particularly limited as long as it outputs light including a wavelength suitable for the intended use. In particular, when the light emitting element is used as a gas concentration measuring device, it is not particularly limited as long as it outputs light including a wavelength absorbed by the gas to be detected. Specific examples of the light-emitting element include a MEMS (Micro Electro Mechanical Systems) heater and a light-emitting diode (Light Emitting Diode: LED). Such a light-emitting element may output only light in a wavelength band where absorption of the detection gas is large from the viewpoint of reducing noise due to light absorption of components other than the detection gas.

  From the viewpoint that the emission wavelength band can be controlled by the band gap of the light emitting layer, the light emitting element preferably has an LED structure. When the light source of the LED structure is used, the band gap of the material used for the light emitting layer is adjusted to the absorption wavelength of the gas to be detected, so that an optical filter (for example, a bandpass filter) can be used without using a specific gas. Detection is possible, and a gas sensor without an optical filter can be realized. If a gas sensor without an optical filter can be realized, the structure of the gas concentration measuring device can be simplified.

  Further, the inventors of the present invention, when at least a part of the light emitting element is sealed with the mold resin, the stress applied to the light emitting element changes due to the influence of moisture absorption and / or drying of the mold resin portion. This time, it was newly discovered that the light emission amount of the light emitting element fluctuates. Therefore, by measuring information (humidity information) correlated with the humidity of the mold resin part, it is possible to compensate for the influence of fluctuations in the light emission amount of the light emitting element due to moisture absorption of the mold resin part.

  As will be described later, the inventors calculate information (humidity information) correlated with the humidity of the mold resin portion based on temperature information and information on at least one of the electrical characteristics and optical characteristics of the light emitting element. I found something new that I can do. Thus, information (humidity information) correlated with the humidity of the mold resin portion is obtained by measuring information on at least one of the electrical characteristics and optical characteristics of the light emitting element, and the obtained temperature information and humidity information are obtained. The output of the light emitting element can be controlled using

In the light emitting device and the light emitting and receiving device according to the present embodiment, the light emitting element has a diode structure including indium, including at least one of arsenic and antimony, and including at least a P-type semiconductor layer and an N-type semiconductor layer. May be. Thus, particularly in the gas concentration measuring device for measuring the concentration of CO _2, it is possible to increase the amount of light emitted infrared around 4.3μm, which is an absorption wavelength band of CO _2.
In the light emitting device and the light receiving and emitting device according to the present embodiment, the light emitting element may include an auxiliary element as will be described later.

<Temperature information acquisition unit>
The temperature information acquisition unit in the light receiving device according to the present embodiment acquires temperature information of the light receiving device. In this case, the temperature information may include information on the temperature of the light receiving element or the temperature of the mold resin portion. In this case, the temperature information may include information on at least one of the electrical characteristics and the optical characteristics of the light receiving element.

  The temperature information acquisition unit in the light emitting device according to the present embodiment acquires temperature information of the light emitting device. In this case, the temperature information may include information on the temperature of the light emitting element or the temperature of the mold resin portion. In this case, the temperature information may include information on at least one of electrical characteristics and optical characteristics of the light emitting element.

The temperature information acquisition unit in the light emitting / receiving device according to the present embodiment acquires temperature information of the light receiving / emitting device. In this case, the temperature information may include information on at least one of the temperature of the light receiving element, the temperature of the light emitting element, and the temperature of the mold resin portion. In this case, the temperature information may include information on at least one of the electrical characteristics and the optical characteristics of at least one of the light receiving element and the light emitting element.
In the light receiving device, the light emitting device, and the light emitting / receiving device according to the present embodiment, in the case where an auxiliary element, which will be described later, is sealed at least partially in the mold resin portion, the temperature information is the electrical characteristics of the auxiliary element. And information on at least one of the optical characteristics.

  In particular, when the temperature change in the measurement environment is fast, or when the equilibrium state between the light receiving element and the light emitting element and the measurement environment cannot be maintained, information on the temperature of the light receiving element or the light emitting element may be used as the temperature information.

  On the other hand, when the temperature change in the measurement environment is slow and the light receiving element and the light emitting element and the measurement environment are kept in an equilibrium state, for example, a temperature sensor installed separately on the substrate on which the light receiving element and the light emitting element are mounted. For example, the temperature of the environment can be measured and the measured temperature can be used as temperature information.

  As means for acquiring temperature information in this case, specifically, a temperature sensor such as a thermistor, a platinum (Pt) resistance temperature detector, or a diode can be used.

The temperature information acquired by the temperature information acquisition unit is not limited to the temperature itself, and the temperature information may be calculated from the electrical characteristics and optical characteristics of the light receiving element and the light emitting element, which are physical quantities affected by the temperature. . Here, the electrical characteristics characterize the characteristics of the light-emitting element and the light-receiving element such as current-voltage characteristics, output resistance (internal resistance) in the vicinity of no bias obtained from the current-voltage characteristics, and forward voltage drop. A physical quantity. The optical characteristics refer to physical quantities that characterize the characteristics of the light emitting element and the light receiving element, such as the amount of light emitted from the light emitting element and the photocurrent (output signal) in the light receiving element. Although these physical quantities are affected by factors other than temperature, necessary information (humidity information) can be extracted from these physical quantities by a humidity information calculation unit, a compensation unit, and a control unit described later. For this reason, it is possible to compensate for the output signal of the light receiving element and control the light emitting element by using these physical quantities.
Hereinafter, the electrical characteristics and optical characteristics of the light receiving element and the light emitting element respectively mean the physical quantities described above.

  The temperature information acquisition unit in the light emitting and receiving device according to the present embodiment outputs the acquired temperature information to a compensation unit and a humidity information calculation unit described later. Here, the “temperature information” output to the compensation unit and the “temperature information” output to the humidity information calculation unit may be information (data) related to the temperature information, respectively, and have the same information format. It is not limited to. For example, when different temperature information corrected by different correction formulas based on the same temperature information is output to the compensation unit and the humidity information calculation unit, it goes without saying that they are included in the scope of the present invention. Further, the forward voltage drop of the light emitting element is set as temperature information to be output to the humidity information calculation unit, the temperature information acquisition unit acquires the output of the temperature sensor on the outside or the same mounting board, and is output to the compensation unit. It is also possible to do. Of course, the temperature information acquisition unit acquires the output of the temperature sensor installed outside the light emitting and receiving device or on the same mounting board, and outputs it to the compensation unit and the humidity information calculation unit as common “temperature information”. it can.

  The same applies to the temperature information acquisition unit in the light emitting device according to the present embodiment and the temperature information acquisition unit in the light receiving device according to the present embodiment. The same applies to the temperature information output from the temperature information acquisition unit to the control unit in the light emitting device and the light receiving and emitting device.

<Humidity information calculation unit>
The humidity information calculation unit in the light receiving device according to the present embodiment calculates the humidity information based on the temperature information and information on at least one of the electrical characteristics and the optical characteristics of the light receiving element. As a result, the light receiving device can obtain humidity information for compensating the characteristic variation of the light receiving element due to moisture absorption and drying of the mold resin. In this case, the humidity information may include information on at least one of the electrical characteristics and the optical characteristics of the light receiving element.

  The humidity information calculation unit in the light emitting device according to the present embodiment calculates the humidity information based on the temperature information and information on at least one of the electrical characteristics and the optical characteristics of the light emitting element. Thereby, the light emitting device can obtain humidity information for compensating for the characteristic variation of the light emitting element due to moisture absorption-drying of the mold resin. In this case, the humidity information may include information on at least one of electrical characteristics and optical characteristics of the light emitting element.

  The humidity information calculation unit in the light emitting / receiving device according to the present embodiment calculates humidity information based on the temperature information and information on at least one of the electrical characteristics and optical characteristics of the light emitting element and the light receiving element. Thereby, the light receiving / emitting device can obtain humidity information for compensating for the characteristic variation of the light receiving element and the light emitting element due to moisture absorption-drying of the mold resin. In this case, the humidity information may include information on at least one of the electrical characteristics and the optical characteristics of at least one of the light receiving element and the light emitting element.

  In the light receiving device, the light emitting device, and the light receiving and emitting device according to the present embodiment, when the auxiliary element (details will be described later) further sealed at least partially in the mold resin portion is provided, the humidity information is the temperature information and And may be calculated based on information on at least one of the electrical characteristics and the optical characteristics of the auxiliary element. In this case, the humidity information may include information on at least one of the electrical characteristics and the optical characteristics of the auxiliary element.

As the auxiliary element, for example, a diode or a resistor provided in the mold resin portion, or at least one of a diode and a resistor formed of the same material as the light receiving element and the light emitting element can be used.
Further, the electrical characteristics and optical characteristics of the light receiving element, the light emitting element, or the auxiliary element used for calculating the humidity information are affected not only by the humidity but also by the temperature. Therefore, it is possible to calculate the humidity information by removing those temperature dependencies based on the temperature information.

As described above, the humidity information calculated by the humidity information calculation unit is not limited to the humidity itself, but relates to electrical characteristics and optical characteristics that are physical quantities that are affected by the swelling stress caused by moisture absorption of the mold resin part due to humidity. Information or a combination thereof may be used. Although these physical quantities are affected by temperature, a compensation unit and a control unit, which will be described later, can reduce the influence of temperature from these physical quantities and extract information (humidity information) having a large degree of influence due to humidity. For example, by correcting the internal resistance of the light emitting element using temperature information, there is no temperature dependency, and the amount of change in internal resistance due to the moisture absorption state of the mold resin, that is, humidity information can be obtained. By compensating the output signal of the light receiving element and controlling the light emitting element based on the humidity information, it is possible to configure a light receiving device, a light emitting device, and a light receiving and emitting device that are compensated for the influence of temperature and humidity.
In addition, when using the electrical characteristics and optical characteristics of a light receiving element or a light emitting element as temperature information, it is necessary to use a different one from the electrical characteristics and optical characteristics used for calculating humidity information. For example, in the case of a light emitting device, when the forward voltage drop of the light emitting element is used as the temperature information, the physical quantity other than the forward voltage drop of the light emitting element (for example, the internal resistance of the light emitting element or the light emitting element) is used for calculating the humidity information. It is necessary to use a photocurrent of a photodiode provided as an auxiliary element. The same applies to light emitting devices and light emitting / receiving devices.

<Mold resin part>
In the light receiving device, the light emitting device, and the light receiving and emitting device according to the present embodiment, the mold resin portion may seal at least a part of the light receiving element and at least a part of the light emitting element. Alternatively, the mold resin portion may seal at least one of the light receiving element and at least a part of the light emitting element. As a forming material of the mold resin portion, for example, a resin mold material such as an epoxy resin or a phenol resin can be used. At that time, the resin mold material may include a filler such as SiO ₂ or Al ₂ O ₃ . Further, a stress relaxation layer (buffer layer) such as polyimide, polyamide, or silicone resin may be included between at least one of the light receiving element and the light emitting element and the mold resin portion.

  In the light emitting / receiving device of the present embodiment, the mold resin portion has a light receiving side sealing region that seals at least a part of the light receiving element and a light emitting side sealing region that seals at least a part of the light emitting element. You may do it. In this case, the light receiving side sealing region and the light emitting side sealing region may be in spatial contact.

<Compensation part>
In the light receiving device and the light receiving and emitting device according to the present embodiment, the compensation unit is not particularly limited as long as it can compensate the output signal of the light receiving element based on the temperature information and the humidity information. For example, an analog IC, a digital IC, and a central processing unit (CPU) are suitable as the compensation unit.

The temperature information and humidity information acquired from the temperature information acquisition unit and the humidity information calculation unit are not limited to the temperature and humidity values themselves, but the electrical resistance value and photocurrent whose characteristics change under the influence of temperature and humidity. Information calculated from physical quantities such as values is also included. In addition, the compensation unit may have a storage area that stores data in which the influence of temperature and humidity is calibrated in advance, and may exhibit a function for controlling the light emitting element.

<Control unit>
In the light emitting device and the light emitting / receiving device according to the present embodiment, the control unit is not particularly limited as long as it can control the light emitting element based on the temperature information and the humidity information, and for example, an analog IC, a digital IC, a CPU, and the like. A drive circuit including is preferable.

  When the light emitting element is an LED, the control unit may be able to control at least one of the input current value, the energization time, and the non-energization time of the light emitting element, for example.

  The temperature information and humidity information acquired from the temperature information acquisition unit and the humidity information calculation unit are not limited to the temperature and humidity values themselves, but the electrical resistance value and photocurrent whose characteristics change under the influence of temperature and humidity. Information calculated from physical quantities such as values is also included. The control unit of the light emitting element may have a storage area for storing data in which the influence of temperature and humidity is calibrated in advance, or may exhibit a function for compensating the output signal of the light receiving element. Good.

<Auxiliary element>
The light-receiving device, the light-emitting device, and the light-emitting / receiving device according to this embodiment further include an auxiliary element that is at least partially sealed in the mold resin portion, and at least one of temperature information and humidity information is an electrical characteristic of the auxiliary element. And information on at least one of the optical characteristics. As the auxiliary element, for example, a diode or a resistor provided in the mold resin portion, or a diode or a resistor made of the same material as the light receiving element or the light emitting element can be used. In this case, the auxiliary element may be formed on the same substrate as the light receiving element. In this case, a plurality of auxiliary elements may be arranged on the substrate. The plurality of auxiliary elements may be connected in parallel, series, or series-parallel, and may form a Wheatstone bridge.

  In particular, when the auxiliary element and the light receiving element or the light emitting element are provided on the same substrate, the temperature of the light receiving element or the light emitting element and the auxiliary element can be brought close to thermal equilibrium by heat conduction through the substrate.

  In the light-receiving device, light-emitting device, and light-emitting / receiving device according to the present embodiment, it is generally difficult to avoid the proximity of different materials. Therefore, the thermal stress due to the difference in thermal expansion coefficient and the moisture absorption of the sealing portion due to humidity are difficult. The influence of the resulting swelling stress varies depending on the position of the substrate on which the light receiving element and the light emitting element are provided (part of the substrate). In this case, a plurality of auxiliary elements are further provided at a plurality of positions on the same substrate, and at least one of the electrical characteristics and the optical characteristics of each of the plurality of auxiliary elements is measured. It is possible to acquire at least one of temperature information and humidity information by comparing or evaluating a characteristic change due to at least one of the wet stress. Specifically, temperature information and humidity information are extracted by acquiring the temperature dependence of at least one of the electrical and optical characteristics of the auxiliary element in the dry state, and then acquiring the same characteristics in a humidity environment. Therefore, it is possible to extract a correction parameter for this purpose.

  Here, on the same substrate, when the light receiving element, the light emitting element, and the auxiliary element are mounted on a printed wiring board (mounting board) and sealed, the same printed wiring is sealed in the same manner. Point on the board. Alternatively, when the light receiving element, the light emitting element, and the auxiliary element are formed on a silicon (Si) substrate, a gallium arsenide (GaAs) substrate, a glass substrate, or the like, Point to. When the light receiving element and the light emitting element have a diode structure including a P-type semiconductor layer and an N-type semiconductor layer, the auxiliary element may have the same diode structure, or the P-type semiconductor layer and the N-type semiconductor layer. May be a resistor.

  In the light receiving device, the light emitting device, and the light emitting / receiving device of the present embodiment, the auxiliary element includes indium, includes at least one of arsenic and antimony, and has a diode structure including at least a P-type semiconductor layer and an N-type semiconductor layer. Or a resistor.

Next, embodiments of the present invention will be described with reference to the drawings.
[Embodiment 1]
FIG. 1 is a configuration diagram for explaining a light receiving device according to a first embodiment of the present invention. As shown in FIG. 1, the light receiving device 2 of the first embodiment includes a substrate 26, a light receiving element 21 and an auxiliary element 27 formed on the substrate 26, and at least one of the light receiving element 21, the auxiliary element 27, and the substrate 26. Based on the temperature information TI obtained from the temperature information acquisition unit 23, the temperature information acquisition unit 23, the humidity information calculation unit 24, the temperature information acquisition unit 23, and the humidity information HI obtained from the temperature information acquisition unit 24. And a compensator 25 for compensating the output signal SO from the light receiving element 21.

[Embodiment 2]
FIG. 2 is a configuration diagram for explaining a light emitting device according to a second embodiment of the present invention. As shown in FIG. 2, the light emitting device 4 according to the second embodiment includes a substrate 46, a light emitting element 48 and an auxiliary element 47 formed on the substrate 46, and at least a light emitting element 48, an auxiliary element 47, and the substrate 46. Humidity information acquired from the temperature information TI and humidity information calculation unit 44 acquired from the mold resin unit 42 that seals a part, the temperature information acquisition unit 43, the humidity information calculation unit 44, and the temperature information acquisition unit 43. And a control unit 49 that outputs a control signal SC for controlling the light emitting element 48 based on the HI.

[Embodiment 3]
FIG. 3 is a configuration diagram for explaining a light emitting and receiving device according to a third embodiment of the present invention. As illustrated in FIG. 3, the light receiving and emitting device 5 according to the third embodiment includes a light receiving side substrate 561, a light receiving element 51 and a light receiving side auxiliary element 571 formed on the light receiving side substrate 561, the light receiving element 51, and light receiving. A light receiving side sealing region 521 that seals at least a part of the side auxiliary element 571 and the light receiving side substrate 561, a light emitting side substrate 562, a light emitting element 58 formed on the light emitting side substrate 562, and a light emitting side auxiliary element 572. A light emitting side sealing region 522 that seals at least a part of the light emitting element 58, the light emitting side auxiliary element 572, and the light emitting side substrate 562, a temperature information acquisition unit 53, a humidity information calculation unit 54, and a temperature information acquisition unit. Compensation unit 55 for compensating the output signal SO of the light receiving element 51 based on the temperature information TI acquired from the temperature information 53 and the humidity information HI acquired from the humidity information calculation unit 54, and the temperature information TI and the humidity information HI Zui and and a control unit 59 for outputting a control signal SC for controlling the light-emitting element 58. The light emitting / receiving device 5 includes a mold resin portion 52 having a light receiving side sealing region 521 and a light emitting side sealing region 522. The light receiving side sealing region 521 and the light emitting side sealing region 522 are provided spatially separated.

  Here, an example of a method for compensating for the influence of temperature and humidity in the present invention will be described using an example in which the light emitting and receiving device 5 according to the third embodiment is adapted to a gas concentration measuring device. Specifically, the form which installed the light emitting / receiving apparatus 5 which concerns on 3rd Embodiment in the gas cell is assumed. Here, the gas cell allows the gas to be detected to flow in due to diffusion with the external environment, etc., and reflects or condenses the light emitted from the light emitting element using the internal mirror surface or the like. A structure having an optical path leading to the light receiving element. The light propagating in the gas cell is absorbed by the gas according to the propagation distance and the gas concentration, and the amount of light reaching the light receiving element is attenuated. Therefore, the gas concentration is measured by measuring and evaluating the amount of change in the amount of light propagating in the gas cell. The gas concentration measuring device having the configuration of the light receiving and emitting device 5 according to the third embodiment can obtain a gas concentration calculation formula by the operation described below as an example.

  As the temperature information T obtained from the temperature information acquisition unit, for example, a temperature obtained from a temperature sensor attached to the light receiving and emitting device is used. Based on this temperature information T, for example, a correction amount h (T for correcting the temperature dependence of the output by measuring the temperature dependence of the output of the light receiving element in a dry state where there is no gas to be detected and humidity is 0%. ) Is obtained. This correction equation can be expressed as equation (1).

  Subsequently, based on the temperature information T and the internal resistance r (H, T) of the light emitting element, for example, by measuring the temperature dependence of the internal resistance in a dry state where there is no gas to be detected and the humidity is 0%, A correction formula for obtaining a correction amount f (H) for correcting the temperature dependence of the resistance is obtained. This correction equation can be expressed as in equation (2).

  This correction amount f (H) is an amount obtained by removing the temperature dependency from the internal resistance of the light emitting element that changes depending on the temperature and humidity. Humidity information that varies depending on the humidity (hereinafter, the sign of the humidity information is also referred to as “f”). (H) "is used). Alternatively, a polynomial may be constructed based on the humidity information f (H) shown in Expression (2) and used again as humidity information f2 (H) as shown in Expression (3). The temperature information TI obtained from the temperature information acquisition unit corresponds to the temperature information TI shown in FIG. 3, and the humidity information f (H) and the humidity information f2 (H) correspond to the humidity information HI shown in FIG. .

Subsequently, based on the correction amount h (T) obtained from the temperature information TI obtained from the temperature information acquisition unit and the humidity information f (H) obtained from the humidity information calculation unit, the output signal I _out of the light receiving element is as follows: As a result of the correction, the output signal corrected for the influence of temperature and humidity, that is, the gas concentration c can be calculated.

Here, constants A1, B1, C1 in formula (1), constants D1, E1, F1 in formula (2), constants D2, E2, F2 in formula (3), constants J, in formula (4), K and L are correction coefficients acquired in advance by fitting in order to remove temperature dependence and humidity dependence. In particular, for the constants J, K, and L, the coefficient that minimizes the error is derived by measuring the output signal while changing the gas concentration to be measured. By using these constants and correction equations, the temperature dependence and humidity dependence corrected gas concentration c based on the output signal I _out of the light receiving element and the internal resistance r of the light emitting element at each temperature and each humidity state. Can be calculated.

  By correcting the output signal of the light receiving element based on the temperature information and the humidity information through the above process, it is possible to realize a gas concentration measuring device with higher accuracy than the conventional gas concentration measuring device.

  In the third embodiment, the correction of the output signal of the light receiving element by the output from the temperature information acquisition unit is a quadratic expression, and the compensation for calculating the humidity information based on the temperature information and the internal resistance of the light emitting element is a quadratic expression. Further, the compensation of the output signal of the light receiving element 51 for calculating the final gas concentration is performed by a quadratic equation, but this is an example, and the technical scope of the present invention is not limited to the above. .

  As another method, the measurement accuracy of the gas concentration can be improved by increasing the order of compensation by using a quadratic expression instead of the primary expression, or a cubic expression instead of the quadratic expression. Also, the inverse of a polynomial, an exponential function, or a logarithmic function can be used. On the other hand, if the compensation order increases or the compensation function becomes complex, the number of measurement points (temperature, humidity, gas concentration) required to obtain a calibration curve increases, so the compensation order and compensation function are It can be appropriately determined depending on the balance between required accuracy and manufacturing cost. Even if the temperature information includes humidity information, by using electrical and optical characteristics that are different from those of the humidity information calculation unit, the compensation unit can be configured to remove the humidity dependence in the compensation unit. A corrected signal of the influence of temperature and humidity can be obtained.

[Embodiment 4]
The light emitting / receiving device according to the fourth embodiment of the present invention is a light emitting / receiving device in which the light emitting element 58 is a mid-infrared LED in the third embodiment described above.

[Embodiment 5]
The light emitting / receiving device according to the fifth embodiment of the present invention is a light emitting / receiving device in which the light receiving element 51 and the light receiving side auxiliary element 571 have the same thin film structure in the third embodiment or the fourth embodiment described above. Here, the thin film structure is a PIN diode structure in which a P-type semiconductor layer, an I-type semiconductor layer (undoped layer), and an N-type semiconductor layer are stacked. Since the light receiving element 51 and the light receiving side auxiliary element 571 have the same thin film structure, there is an advantage that the characteristic variation due to the temperature change is easily compensated and the manufacturing process is shortened.

[Embodiment 6]
The light emitting / receiving device according to the sixth embodiment of the present invention is the light receiving side sealing region 521 for sealing the light receiving element 51 and the light emitting side sealing for sealing the light emitting element 58 in the fourth or fifth embodiment described above. The stop region 522 is in spatial contact (the light-receiving side sealing region 521 and the light-emitting side sealing region 522 are formed of one sealing material). That is, the light emitting / receiving device according to the sixth embodiment is characterized in that it includes a mold resin portion 52 having a light receiving side sealing region 521 and a light emitting side sealing region 522 that are in spatial contact. . The light emitting / receiving device according to the sixth embodiment has an advantage that the light receiving element 51 and the light emitting element 58 can be sealed in the same process, and the manufacturing process can be shortened.

[Embodiment 7]
In the light receiving device, the light emitting device, and the light receiving / emitting device according to the seventh embodiment of the present invention, the light receiving element, the light emitting element, and the compensation element are the AlInSb layers formed on the GaAs substrate in the first to sixth embodiments described above. It is characterized in that it has a PIN diode structure having an active layer (I layer) formed. Here, the composition ratio of aluminum (Al) in the active layer is 0 to 20%, and barrier layers for blocking carriers (electrons and holes) may be formed above and below the active layer. Further, a P layer and an N layer for supplying carriers are formed above and below the active layer. When the Al composition is 2 to 5%, this material can absorb or emit light corresponding to 4.3 μm that is the infrared absorption wavelength of carbon dioxide gas. It is suitable as an element. Alternatively, when the Al composition is 8 to 10%, this material can absorb light or emit light corresponding to the infrared absorption wavelength of 3.3 μm of hydrocarbon gas including methane. Therefore, it is suitable as a light receiving element and a light emitting element.
[Embodiment 8]
In the light receiving device, the light emitting device, and the light receiving / emitting device according to the eighth embodiment of the present invention, the light receiving element, the light emitting element, and the compensation element are formed of an AlInAsSb layer formed on a GaAs substrate in the first to sixth embodiments described above. It is characterized in that it has a PIN diode structure having an active layer (I layer) formed. Here, by setting the Al composition in the active layer to 0 to 5% and the Sb composition to 0 to 5%, it becomes suitable for detecting water (2.7 μm) or methane (3.3 μm). By increasing to 10 to 13%, it is suitable for detecting carbon dioxide gas (4.3 μm).

  Next, a light receiving device, a light emitting device, and a light receiving and emitting device according to examples of the present embodiment will be described. The following examples are examples in the case where the light emitting and receiving device of this embodiment is applied to a carbon dioxide concentration measuring device.

  A light emitting element (mid-infrared LED light source) sealed in a sealing portion, and a quantum infrared sensor as an auxiliary element having the same thin film structure as the light emitting element and used for temperature measurement formed on the same substrate And the quantum type infrared sensor as a light receiving element was arrange | positioned in the dome type | mold gas cell which has a spherical surface with a high reflectance inside. A quantum infrared sensor as a light receiving element has the same thin film structure as a light emitting element.

  An auxiliary element of a light emitting element is connected to the temperature information acquisition unit, and a photocurrent output from the auxiliary element is used as temperature information, and a light emitting element is connected to the humidity information calculation unit to emit light as humidity information. The configuration uses the internal resistance of the element. Here, the light emitting element and the auxiliary element are sealed in the same mold resin part, and it can be modified to a configuration in which the value of the internal resistance of the auxiliary element is connected to the humidity information calculation unit instead of the internal resistance of the light emitting element. is there.

  Next, carbon dioxide of 400 ppm is selected as the first carbon dioxide concentration, 1000 ppm as the second carbon dioxide concentration, and 2000 ppm as the third carbon dioxide concentration. The low temperature described in each embodiment is 10 ° C., and the medium temperature is 25 ° C. The gas concentration calculation formula is derived based on each embodiment, assuming that the temperature is 40 ° C and the temperature is 40 ° C. Using the obtained formula, the carbon dioxide concentration is 400 ppm, 1000 ppm, 2000 ppm, and the temperature is 10, 25 ° C, 40 ° C. Attempts were made to calculate the gas concentration in a dry environment (corresponding to 0% moisture absorption of the sealing part) and to calculate the gas concentration in a high humidity environment at 25 ° C. (corresponding to 100% moisture absorption of the sealing part).

  FIG. 4 is a diagram showing the relationship between the actual concentration of carbon dioxide and the calculated value of carbon dioxide in this example. In FIG. 4, the horizontal axis represents the actual carbon dioxide concentration, and the vertical axis represents the calculated carbon dioxide concentration. In FIG. 4, □ indicates characteristics at 10 ° C. and in a dry environment, ◇ indicates characteristics at 25 ° C. and in a dry environment, and ○ indicates characteristics at 25 ° C. and in a high humidity environment. The Δ mark indicates the characteristics at 40 ° C. and in a dry environment.

<Comparative example>
The carbon dioxide concentration measuring apparatus in this comparative example includes a light emitting element (mid-infrared LED light source) sealed in a mold resin part, a quantum infrared sensor as a light receiving element having the same thin film structure as the light emitting element, Was placed in a dome type gas cell having a highly reflective spherical surface inside. The difference from the carbon dioxide concentration measuring apparatus according to the present embodiment is that the carbon dioxide concentration measuring apparatus in this comparative example does not include a humidity information calculation unit.

  Next, from the following Lambert Bale equation (5), which is a conventional general gas concentration calculation formula, the output of the light receiving element at carbon dioxide concentrations of 400 ppm and 2000 ppm at a temperature of 25 ° C. in a dry environment, and the carbon dioxide concentration Constants A2 and B2 were obtained by fitting the relationship with the following Lambert Bale equation (5).

In equation (5), “c” represents the carbon dioxide concentration, “I _ref ” represents the output of the temperature information acquisition unit, and “I _out ” represents the output of the light receiving element. “A2” and “B2” are constants obtained from the relationship between the output of the light receiving element of the carbon dioxide concentration measuring device in this comparative example, the output of the temperature information acquisition unit, and the carbon dioxide concentration at carbon dioxide concentrations of 400 ppm and 1000 ppm. Represents.

  Using the concentration calculation formula thus obtained, carbon dioxide concentrations of 400 ppm, 1000 ppm, and 2000 ppm at temperatures of 10, 25 ° C., and 40 ° C. in a dry environment (corresponding to 0% moisture absorption at the sealing portion) Attempts were made to calculate the gas concentration and to calculate the gas concentration in a high humidity environment at a temperature of 25 ° C. (corresponding to 100% moisture absorption of the sealing portion).

  FIG. 5 is a diagram showing the relationship between the actual concentration of carbon dioxide and the calculated value of carbon dioxide in the comparative example. In FIG. 5, the horizontal axis represents the actual concentration of carbon dioxide, and the vertical axis represents the calculated value of carbon dioxide. In FIG. 5, □ indicates characteristics at 10 ° C. and in a dry environment, ◇ indicates characteristics at 25 ° C. and in a dry environment, and ○ indicates characteristics at 25 ° C. and in a high humidity environment. The Δ mark indicates the characteristics at 40 ° C. and in a dry environment.

  As shown in FIG. 4, when the gas concentration calculation formula obtained by this example is used, the calculated carbon dioxide concentration is 64 ppm at a carbon dioxide concentration of 400 ppm, 0 ppm at 1000 ppm, and 143 ppm at 2000 ppm relative to the actual carbon dioxide concentration. Fell within the error.

  On the other hand, as shown in FIG. 5, when using the gas concentration calculation formula obtained by the comparative example, the calculated carbon dioxide concentration is 1469 ppm at a carbon dioxide concentration of 400 ppm, 1473 ppm at 1000 ppm, and 2000 ppm with respect to the actual carbon dioxide concentration. An error of 1312 ppm occurred.

  From the above results, according to the light receiving device, the light emitting device, and the light receiving and emitting device according to the present embodiment, it becomes possible to compensate for the influence of temperature and humidity. For example, when used in a gas concentration measuring device, the conventional gas It is understood that the concentration can be calculated with higher accuracy than the concentration measuring device.

  As described above, according to the present embodiment, it is possible to realize a highly accurate light receiving device, light emitting device, and light receiving / emitting device in which the influence of at least one of temperature and humidity is compensated.

  According to the light receiving device according to the present embodiment, for example, when a light receiving element sealed with a mold resin, which is an inexpensive package technology, is used, the influence of temperature and humidity can be compensated, so that high accuracy can be achieved. . In addition, according to the light emitting device according to the present embodiment, for example, when using a light emitting element sealed with a mold resin, which is an inexpensive package technology, the influence of temperature and humidity can be compensated, so that high accuracy can be achieved. Can do. Furthermore, according to the light emitting / receiving device according to the present embodiment, for example, when using a light receiving element and a light emitting element sealed with a mold resin, which is an inexpensive package technology, the influence of temperature and humidity can be compensated, so that high accuracy is achieved. Can be achieved.

  As mentioned above, although embodiment of this invention was described, the technical scope of this invention is not limited to the technical scope as described in embodiment mentioned above. It is possible to add various changes or improvements to the above-described embodiments, and it is possible to add such changes or improvements to the technical scope of the present invention. it is obvious.

2 Light-receiving device 4 Light-emitting device 5 Light-receiving / emitting device 21, 51 Light-receiving element 22, 42, 52 Mold resin part 23, 43, 53 Temperature information acquisition part 24, 44, 54 Humidity information calculation part 25, 55 Compensation part 26, 46 Substrate 27, 47 Auxiliary elements 48, 58 Light emitting elements 49, 59 Control unit 521 Light receiving side sealing area 522 Light emitting side sealing area 561 Light receiving side substrate 562 Light emitting side substrate 571 Light receiving side auxiliary element 572 Light emitting side auxiliary element

Claims (18)

A light receiving element that receives at least part of light incident from the outside and outputs an output signal corresponding to the amount of light received;
A mold resin portion for sealing at least a part of the light receiving element;
A temperature information acquisition unit for acquiring temperature information;
A humidity information calculation unit for calculating humidity information based on information on at least one of the electrical characteristics and optical characteristics of the light receiving element and the temperature information;
A compensation unit for compensating the output signal based on the temperature information and the humidity information;
A light receiving device. The light receiving device according to claim 1, wherein the temperature information includes information related to a temperature of the light receiving element or a temperature of the mold resin portion, and the humidity information includes information related to a humidity of the mold resin portion. An auxiliary element at least partially sealed in the mold resin portion;
The light receiving device according to claim 1, wherein at least one of the temperature information and the humidity information includes information on at least one of electrical characteristics and optical characteristics of the auxiliary element. The light receiving device according to claim 3, wherein the auxiliary element is formed on the same substrate as the light receiving element. The at least one of the light receiving element and the auxiliary element includes indium, includes at least one of arsenic and antimony, has a diode structure including at least a P-type semiconductor layer and an N-type semiconductor layer, or is a resistor. Or a light receiving device according to 4; A light emitting element;
A light receiving element that receives at least part of the light output by the light emitting element and outputs an output signal corresponding to the amount of light received;
A mold resin portion for sealing at least a part of the light receiving element;
A temperature information acquisition unit for acquiring temperature information;
A humidity information calculation unit for calculating humidity information based on information on at least one of the electrical characteristics and optical characteristics of the light receiving element and the temperature information;
A control unit for controlling the light emitting element based on the temperature information and the humidity information;
A light emitting and receiving device. The temperature information includes information on at least one of the temperature of the light receiving element, the temperature of the light emitting element, and the temperature of the mold resin portion, and the humidity information includes information on the humidity of the mold resin portion. The light receiving and emitting device according to claim 6. The light receiving and emitting device according to claim 6 or 7, wherein the temperature information includes information on at least one of electrical characteristics and optical characteristics of at least one of the light receiving element and the light emitting element. The mold resin part is
A light receiving side sealing region for sealing at least a part of the light receiving element;
A light emitting side sealing region for sealing at least a part of the light emitting element;
The light emitting / receiving device according to any one of claims 6 to 8. The light receiving / emitting device according to claim 9, wherein the light receiving side sealing region and the light emitting side sealing region are in spatial contact. A light receiving side auxiliary element sealed at least partially in the light receiving side sealing region;
The light emitting / receiving device according to claim 9 or 10, wherein at least one of the temperature information and the humidity information includes information on at least one of electrical characteristics and optical characteristics of the light receiving side auxiliary element. The light receiving / emitting device according to claim 11, wherein the light receiving side auxiliary element is formed on the same light receiving side substrate as the light receiving element. 13. The light receiving side auxiliary element includes indium, includes at least one of arsenic and antimony, has a diode structure including at least a P-type semiconductor layer and an N-type semiconductor layer, or is a resistor. Light emitting / receiving device. A light emitting side auxiliary element sealed at least partially in the light emitting side sealing region;
The light receiving and emitting device according to any one of claims 9 to 13, wherein at least one of the temperature information and the humidity information includes information on at least one of electrical characteristics and optical characteristics of the light emitting side auxiliary element. The light emitting and receiving device according to claim 14, wherein the light emitting side auxiliary element is disposed on the same light emitting side substrate as the light emitting element. The light emitting side auxiliary element includes indium, includes at least one of arsenic and antimony, has a diode structure including at least a P-type semiconductor layer and an N-type semiconductor layer, or is a resistor. Light emitting / receiving device. The light receiving element includes indium, includes at least one of arsenic and antimony, has a diode structure including at least a P-type semiconductor layer and an N-type semiconductor layer, or is a resistor. The light emitting / receiving device according to item. The light emitting / receiving device according to any one of claims 6 to 17, wherein the light emitting element includes indium, includes at least one of arsenic and antimony, and has a diode structure including at least a P-type semiconductor layer and an N-type semiconductor layer. apparatus.

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