JP6817801B2 - Light emitting element control device and light emitting element control method - Google Patents

Description

The present invention relates to a control device for a light emitting element and a control method for the light emitting element.

The non-dispersive infrared analysis type (NDIR type) gas detector detects a specific gas contained in the gas to be measured by using a light source that emits infrared rays. In such a gas detector, by utilizing the property that each of many gases absorbs an inherent infrared wavelength, when infrared rays are radiated to the sample gas, it is investigated which wavelength is absorbed and how much, and the sample gas is contained. Measure the ingredients and concentration. Further, in such a gas detector, the SN (signal-to-noise) ratio is increased by synchronously detecting the light corresponding to the chopping frequency by mechanical optical chopping, and the influence of external environmental noise is reduced (for example). See Patent Document 1).

Further, instead of the mechanical optical chopping, the measurement is performed by switching between the on state and the off state of the injection current to the infrared light emitting element. As an infrared light emitting element that does not use such mechanical optical chopping, an element has been developed in which a heat generation resistance portion is formed on a thin diaphragm and infrared rays are emitted by radiant heat obtained by heating the heat generation resistance portion (for example). See Patent Document 2).

JP-A-2010-164550 Japanese Unexamined Patent Publication No. 2016-045080

However, the technique described in Patent Document 2 has a problem that it is difficult to dissipate heat due to the heat insulating structure and it depends on heat dissipation from the peripheral portion of the diaphragm, so that an in-plane temperature distribution occurs and temperature drift occurs. It was.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a control device for a light emitting element capable of reducing temperature drift, and a method for controlling the light emitting element.

In order to achieve the above object, in the light emitting element control device (2, 2A, 2B) according to one aspect of the present invention, the plurality of light emitting element units (10a to 10d) do not come into contact with each other on one substrate (11). A light emitting element (1C) in which each of the light emitting element units has a heat storage layer (12) and a heat generating resistor (13), and one of the plurality of the light emitting element units. A control unit (clock generation units 21, 21A, which controls one of a plurality of the light emitting element units to sequentially emit light so that the remaining light emitting element units do not emit light when the element unit is emitting light. 21B, temperature control units 23, 23A, 23B, power supply unit 24, switch unit 25) are provided , and the light emitting element (1C) is provided in contact with the substrate (11) and one surface side of the substrate. There are N heat storage layers (where N is an integer of 2 or more), and each of the N heat storage layers is provided on one surface side of the substrate without contacting each other, and the heat storage layer. Of the surface of the layer, N heat-generating resistors are provided in contact with a surface different from the surface in contact with the substrate, and each of the N heat-generating resistors is a heat storage layer of each of the N heat-generating resistors. a heating resistor provided on the different side from that of the said substrate surface in contact, Ru comprising a.

Further, in the control device (2,2A, 2B) for the light emitting element according to one aspect of the present invention, the control units (clock generation units 21,21A, 21B, temperature control units 23, 23A, 23B, power supply unit 24, switch. The unit 25) may drive each of the plurality of light emitting element units so that the wavelength at which the plurality of light emitting element units (10a to 10d) emit light becomes a predetermined wavelength.

Further, in the control device (2,2A, 2B) for the light emitting element according to one aspect of the present invention, the control units (clock generation units 21,21A, 21B, temperature control units 23, 23A, 23B, power supply unit 24, switch. The unit 25) may drive each of the plurality of light emitting element units so that each of the plurality of light emitting element units (10a to 10d) emits light at a predetermined wavelength.

Further, in the control device (2,2A, 2B) for the light emitting element according to one aspect of the present invention, the control units (clock generation units 21,21A, 21B, temperature control units 23, 23A, 23B, power supply unit 24, switch. The unit 25) may control the light emission timing of each of the plurality of light emitting element units according to the wavelength at which each of the plurality of light emitting element units (10a to 10d) emits light.

Further, in the light emitting element control device (2, 2A, 2B) according to one aspect of the present invention, the light emitting element (1C) includes a temperature detection unit (18) for detecting the temperature of the own element, and the control unit. (Clock generation units 21,21A, 21B, temperature control units 23, 23A, 23B, power supply unit 24, switch unit 25) are a plurality of the light emitting element units (10a to 10a) based on the temperature detected by the temperature detection unit. 10d) Each may be driven.

In order to achieve the above object, the control device (2B) for the light emitting element according to one aspect of the present invention includes a substrate (11), a heat storage layer (12) provided in contact with one surface side of the substrate, and a heat storage layer (12). Light emission including a heat generating resistor (13) provided in contact with a surface of the heat storage layer different from the surface in contact with the substrate, and a temperature detection unit (18) for detecting the temperature of the own element. The element (1,1A, 1B) and a control unit (clock generation unit 21B, temperature control unit 23B, power supply unit 24) for driving the light emitting element based on the temperature detected by the temperature detection unit are provided . The heat storage layer is N (where N is an integer of 2 or more) heat storage layers provided in contact with one surface side of the substrate, and each of the N heat storage layers is one of the substrates. The heat generating resistors are provided on the surface side without contacting each other, and the heat generating resistors are N heat generating resistors provided in contact with the surface side of the heat storage layer, which is different from the surface in contact with the substrate. , Each of the N heat generating resistors is provided on each of the N heat storage layers on a surface side different from the surface in contact with the substrate .

In order to achieve the above object, the light emitting element control method according to one aspect of the present invention is a light emitting element in which a plurality of light emitting element units (10a to 10d) are arranged on one substrate (11) without contacting each other. (1C) , the light emitting element includes a substrate, a heat storage layer, and a heat generation resistor, and the heat storage layers are provided in contact with one surface side of the substrate (where N is N). (2 or more integers) of the heat storage layers, each of the N heat storage layers is provided on one surface side of the substrate without contacting each other, and the heat generation resistor is one of the surfaces of the heat storage layer. , N heat-generating resistors provided in contact with a surface different from the surface in contact with the substrate, and each of the N heat-generating resistors is a surface in contact with the substrate of each of the N heat storage layers. This is a control method in which each of the light emitting element units is provided on each of the different surface sides and controls the light emitting state of the light emitting element including the heat storage layer and the heat generating resistor , and the control unit is a plurality of the light emitting elements. A procedure for controlling one of the plurality of light emitting element units to sequentially emit light so that the remaining light emitting element units do not emit light when one of the light emitting element units is emitting light. Including.

According to the present invention, breakage during manufacturing can be reduced, and breakage due to thermal stress can be reduced.

It is a figure which shows the structural example of the light emitting element which concerns on 1st Embodiment. It is a figure which shows the structural example of the light emitting element which is formed integrally with the heat generating resistor and wiring which concerns on 1st Embodiment. It is a figure which shows the structural example of the light emitting element which concerns on 2nd Embodiment. It is a figure which shows the example of the drift when the light emitting element which formed the heat generation resistor on the upper surface of the heat storage layer is continuously used. It is a figure which shows the structural example of the light emitting element which concerns on 3rd Embodiment. It is a block diagram which shows the structural example of the control device of the light emitting element which concerns on 3rd Embodiment. It is a figure which shows the timing chart of the control device of the light emitting element which concerns on 3rd Embodiment. FIG. 7 is a diagram showing an example of the temperature of the heat storage layer when the light emitting element is driven as shown in FIG. 7. It is a block diagram which shows the structural example of the control device of the light emitting element of the modified example which concerns on 3rd Embodiment. It is a figure which shows the timing chart of the control device of the light emitting element of the modification which concerns on 3rd Embodiment. It is a figure which shows the example of the temperature of the substrate when the light emitting element is driven as shown in FIG. It is a figure which shows the structural example of the light emitting element which concerns on 4th Embodiment. It is a figure which shows the other structural example of the light emitting element which concerns on 4th Embodiment. It is a block diagram which shows the structural example of the control device of the light emitting element which concerns on 4th Embodiment.

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

<First Embodiment>
FIG. 1 is a diagram showing a configuration example of the light emitting element 1 according to the present embodiment. FIG. 1A is a top view of the light emitting element 1 according to the present embodiment. FIG. 1B is a cross-sectional view taken along the line AA'of FIG. 1A of the light emitting device 1 according to the present embodiment.

As shown in FIGS. 1A and 1B, the light emitting element 1 comprises a substrate 11, a heat storage layer 12, a heat generating resistor 13, wiring 14a, wiring 14b, a pad 15a, a pad 15b, and a protective film 16. Be prepared.
The heat storage layer 12 is formed on the upper surface of the substrate 11. The heat generation resistor 13 is formed in contact with the upper surface of the heat storage layer 12 which is different from the surface in contact with the substrate 11. The wiring 14a and the wiring 14b are formed by being connected to, for example, both ends of the heat generating resistor 13. Wiring 14a is connected to the pad 15a. Wiring 14b is connected to the pad 15b. The protective film 16 covers the heat storage layer 12, the heat generation resistor 13, the wiring 14a, and the wiring 14b, and the heat storage layer 12, the wiring 14a, and the upper surface of the wiring 14b (of the surfaces of the heat storage resistor 13, the heat storage layer 12). It is formed in contact with a surface different from the contacting surface).

The substrate 11 is, for example, a phosphate-based glass containing Al ₂ O ₃ (alumina), P ₂ O ₅ (diphosphorus pentoxide) and CeO ₂ (cerium oxide) as main components, Si (silicon), and SiC (silicon carbide). ), It is made of a material such as ceramic.
The heat storage layer 12 is obtained by firing glass powder, and is formed of, for example, a material such as SiO ₂ (silicon dioxide), SiON (silicon nitride), SiN (silicon nitride). Further, the thermal conductivity of the heat storage layer 12 is at least lower than that of the substrate 11.

The heat generating resistor 13 is a material having a coefficient of thermal expansion close to that of the substrate. For example, TaN (tantalum nitride), TaSiO (silicon monoxide tantalum), TaSiNO (silicon nitride tantalum), TaSiC (silicon carbide tantalum), TiSiCO, NbSiO. (Silicon Niob), Polysilicon, TaSiO ₂ (Tantalum Silicon Dioxide), TiON (Titanium Nitride), Luthenium Oxide, W (Tungsten), Mo (Molybdenum), NiCr (Nickyl Chrome), Pt (Platinum), Amorphous Silicon It is made of at least one material of.

The wiring 14a and the wiring 14b are formed of a metal material such as Au (gold), Ag (silver), Cu (copper), Cr (chromium), Al—Si (silicon-containing aluminum alloy), Ni (nickel), and Pt. Has been done. The wiring 14a and the wiring 14b are formed by, for example, sputtering or screen printing. The film thickness is, for example, 0.1 μm to 2.0 μm.
The pads 15a and 15b are formed of a metal material such as Al-Si, Al-Si-Cu (silicon, copper-containing aluminum), or a laminated film (for example, Au / Cr, Au / Ni / Cr) Cu. ..

Protective film 16 is obtained by firing the glass powder, for example, SiO (silicon nitride), SiN, SiON, SiAlON _{(Sialon; Si 3 N 4 -Al 2 O} 3), SiO 2, TaO ( tantalum oxide), diamond It is made of a metal material such as like carbon. The film thickness is, for example, 4 μm to 20 μm.

In the light emitting element 1, the heat generating resistor 13 generates heat by passing a current or applying a voltage to the wiring 14a and the wiring 14b. Then, the light emitting element 1 emits infrared rays having a peak wavelength of 3 μm or more or far infrared rays having a peak wavelength of 10 μm or more by thermal radiation from the heat generating resistor 13 due to Joule heat generated by heat generation.

As shown in the configuration shown in FIG. 1, in the light emitting element 1 of the present embodiment, since the heat storage layer 12 and the heat generating resistor 13 are formed on the substrate 11, a thin diaphragm as in the conventional case is unnecessary. Therefore, according to the present embodiment, the thin diaphragm is not damaged during manufacturing, and is not damaged by thermal stress due to a sudden deviation of heat distribution in the diaphragm surface during heat generation. As a result, according to the present embodiment, damage during manufacturing can be reduced, and damage due to thermal stress can be reduced. Further, as described above, in the light emitting element 1 of the present embodiment, the heat generating resistor 13 formed on the ceramic substrate 11 can be used for emitting infrared rays or far infrared rays by this configuration.

The heat generating resistor 13, the wiring 14a, and the wiring 14b may be integrally formed as shown in FIG. FIG. 2 is a diagram showing a configuration example of a light emitting element 1A in which a heat generating resistor and wiring according to the present embodiment are integrally formed. Although the protective film 16 (FIG. 1) is omitted in FIG. 2, the protective film 16 is formed on the upper surface of the heat generating resistor 13 as in FIG. 1.

<Second Embodiment>
FIG. 3 is a diagram showing a configuration example of the light emitting element 1B according to the present embodiment. FIG. 3A is a top view of the light emitting element 1B according to the present embodiment. FIG. 3B is a cross-sectional view taken along the line AA'of FIG. 3A of the light emitting device 1 according to the present embodiment.

As shown in FIGS. 3A and 3B, the light emitting element 1 includes a substrate 11, a heat storage layer 12, a heat generating resistor 13, wiring 14a, wiring 14b, pad 15a, pad 15b, protective film 16, and infrared rays. A radiation layer 17 (radiation layer) is provided. That is, the light emitting element 1B of the present embodiment is the upper surface of the protective film 16 of the light emitting element 1 (or the light emitting element 1A) described in the first embodiment (the surface of the protective film 16 that is in contact with the heat generating resistor 13). The infrared radiation layer 17 is further in contact with the different surface side).

The infrared radiation layer 17 is a high radiation zone having a radiation coefficient of, for example, 0.9 or more, and is formed of, for example, a black body (platinum black or the like), a carbon material, carbon nanofibers, or the like.
The material having the other configuration is the same as that of the light emitting element 1 of the first embodiment.

With the configuration shown in FIG. 3, in the present embodiment, the same effect as in the first embodiment can be obtained. Further, according to the present embodiment, radiation can be performed with a spectrum close to the spectrum of blackbody radiation of the infrared radiating zone 17 formed on the upper surface of the heat generating resistor 13. In other words, the intensity of the emitted infrared rays can be further increased as compared with the configuration of the light emitting element 1 of the first embodiment.

<Third Embodiment>
In the first embodiment and the second embodiment, an example in which the heat generation resistor 13 is formed on the upper surface of the heat storage layer 12 has been described. When the light emitting element is formed in this way, heat may be accumulated in the heat storage layer 12 depending on the usage environment and the usage state, and the temperature at the steady state may gradually drift.

FIG. 4 is a diagram showing an example of drift when a light emitting element having a heat generating resistor 13 formed on the upper surface of the heat storage layer 12 is continuously used. In FIG. 4, the horizontal axis represents time and the vertical axis represents temperature. Further, FIG. 4 shows an example in which light emission is performed five times in a row.
As shown in FIG. 4, the temperature of the heat storage layer 12 for the first light emission is T1, and the temperature of the heat storage layer 12 for the second light emission is T2, which is higher than T1. Further, the temperature of the heat storage layer 12 for the third light emission is T3, which is higher than T2, and the temperature of the heat storage layer 12 for the fourth light emission is T4, which is higher than T3. Further, the temperature of the heat storage layer 12 for the fifth emission is T5, which is higher than T4.

In this way, when light emission is continuously performed, the heat of the heat storage layer 12 is accumulated, and the temperature may rise due to drift.
Therefore, in the present embodiment, a plurality of light emitting element units are formed on the substrate, and the control unit alternately emits light from the plurality of light emitting element units to reduce the influence of drift.

First, a configuration example of the light emitting element will be described.
FIG. 5 is a diagram showing a configuration example of the light emitting element 1C according to the present embodiment.
As shown in FIG. 5, the light emitting element 1C of the present embodiment includes four light emitting element units 10a to 10d. Each of the light emitting element units 10a to 10d includes a substrate 11, a heat storage layer 12, a heat generating resistor 13, a wiring 14a, a wiring 14b, a pad 15a, a pad 15b, and a protective film 16 in the same manner as the light emitting element 1. In the following description, when one of the light emitting element units 10a to 10d is not specified, it is referred to as a light emitting element unit 10. Further, as shown in FIG. 5, each of the light emitting element units 10 is formed without contacting each other.

Next, an example of a circuit for controlling the light emitting element will be described.
FIG. 6 is a block diagram showing a configuration example of the control device 2 for the light emitting element according to the present embodiment. As shown in FIG. 6, the control device 2 of the light emitting element includes a clock generation unit 21, an operation unit 22, a temperature control unit 23, a power supply unit 24, a switch unit 25, a light emitting element 1C, a light receiving element 26, and a lock-in amplifier 27. To be equipped.

The control device 2 of the light emitting element emits, for example, infrared rays having a peak wavelength of 3 μm or more and far infrared rays having a peak wavelength of 10 μm or more, and detects the components of the vaporized gas by spectroscopy.

The clock generation unit 21 generates a clock signal CLK having a predetermined frequency, and outputs the generated clock signal to the switch unit 25 and the lock-in amplifier 27.
The operation unit 22 is, for example, a mechanical switch, a touch panel sensor, or the like. The operation unit 22 detects the operation result operated by the user and outputs the detected operation result to the temperature control unit 23. For example, the user operates the operation unit 22 when starting the inspection of the sample.

The temperature control unit 23 is an instruction to output a voltage value V1 in which the temperature of the heat storage layer 12 of the light emitting element 1C is Ta from the power supply unit 24 for a predetermined period according to the operation result output by the operation unit 22. Is output to the power supply unit 24. The temperature target controlled by the temperature control unit 23 is a temperature corresponding to the wavelength of the substance to be detected.
The power supply unit 24 supplies electric power having a voltage value of V1 to the switch unit 25 during a period in which the temperature control unit 23 outputs a control signal.

The switch unit 25 includes SW251 to SW254. SW251 is the first timing of the clock signal CLK output by the clock generation unit 21 during the period when the power supply unit 24 is outputting the voltage Va of the voltage value V1, the fifth timing, ..., {1 + 4n (N is an integer of 1 or more)} At the third timing, the voltage Va having a voltage value of V1 is supplied to the light emitting element unit 10a. The SW252 has a second timing, a sixth timing, ..., (2 + 4n) th timing of the clock signal CLK during the period when the power supply unit 24 outputs the voltage Vb of the voltage value V1. A voltage Vb having a voltage value of V1 is supplied to the light emitting element unit 10b. In the period in which the power supply unit 24 outputs the voltage Vc of the voltage value V1, the SW253 has the third timing, the seventh timing, ..., (3 + 4n) th timing of the clock signal CLK. A voltage Vc having a voltage value of V1 is supplied to the light emitting element unit 10c. The SW254 is the fourth timing, the eighth timing, ..., (4 + 4n) th timing of the clock signal CLK during the period when the power supply unit 24 outputs the voltage Vc of the voltage value V1. The voltage Vd having a voltage value of V1 is supplied to the light emitting element unit 10d.

As shown in FIG. 5, the light emitting element 1C is an element that emits infrared rays and includes four light emitting element units 10a to 10d. The light emitting element unit 10a is driven by the voltage Va output by SW251 and emits infrared rays. The light emitting element unit 10b is driven by the voltage Vb output by SW252 and emits infrared rays. The light emitting element unit 10c is driven by the voltage Vc output by SW253 and emits infrared rays. The light emitting element unit 10d is driven by the voltage Vd output by SW254 and emits infrared rays.

The light receiving element 26 is an element capable of receiving a wavelength in the band emitted by the light emitting element 1C. The light receiving element 26 converts the received light into an electric signal, and outputs the converted electric signal to the lock-in amplifier 27.

The lock-in amplifier 27 includes a multiplication unit and an LPF (low-pass filter) unit. The lock-in amplifier 27 uses heterodyne technology to detect an electrical signal having the same frequency as the reference signal. Here, the reference signal is the clock signal CLK output by the clock generation unit 21. The measurement signal is an electric signal output by the light receiving element 26. Specifically, the lock-in amplifier 27 performs LPF processing after multiplying the reference signal and the measurement signal. As a result, the lock-in amplifier 27 outputs only the signal that has passed through the LPF, with only the component equal to the frequency of the reference signal as the DC component among the various signals included in the measurement signal. The cutoff frequency of the LPF is set in advance according to the frequency to be detected. The output destination is, for example, an image display device, a printing device, or the like.

An operation example of the control device 2 of the light emitting element will be described.
FIG. 7 is a diagram showing a timing chart of the control device 2 for the light emitting element according to the present embodiment. In FIG. 7, the horizontal axis represents time, the vertical axis of waveforms g1 to g6 represents the level of each signal, and the vertical axis of waveforms g7 to g10 represents temperature. Further, the waveform g1 represents a control signal, the waveform g2 represents a clock signal CLK, the waveform g3 represents a voltage Va, the waveform g4 represents a voltage Vb, the waveform g5 represents a voltage Vc, and the waveform g6 represents a voltage Vd. Further, the waveform g7 is the temperature rise of the heat storage layer 12 of the light emitting element unit 10a, the waveform g8 is the temperature rise of the heat storage layer 12 of the light emitting element unit 10b, the waveform g9 is the temperature rise of the heat storage layer 12 of the light emitting element unit 10c, and the waveform g10 is. It represents the temperature rise of the heat storage layer 12 of the light emitting element unit 10d.

The clock generation unit 21 outputs the generated clock signal CLK as shown in the waveform g2 to the switch unit 25.
At time t1, the temperature control unit 23 starts outputting a control signal in which the voltage value output by the power supply unit 24 is Ta, as shown in the waveform g1.

At the time t2 of the first rise of the clock signal CLK after the output of the control signal is started, the SW251 starts outputting the voltage Va having a voltage value of V1 to the light emitting element unit 10a as shown in the waveform g3. .. The SW251 continues to output the voltage value V1 during the period of time t2 to t3 when the clock signal CLK is H level. The light emitting element unit 10a emits light during the period t2 to t3 when the voltage value of the voltage Va is V1. As a result, as shown in the waveform g7, the temperature of the heat storage layer 12 (FIG. 5) of the light emitting element unit 10a rises due to radiation, the temperature of the heat storage layer 12 reaches, for example, Ta, and the output of the voltage Va falls below a predetermined value. After the time t3 after the change, the temperature gradually decreases.

At the time t4 of the second rising edge of the clock signal CLK after the output of the control signal is started, the SW252 starts outputting the voltage Vb having a voltage value of V1 to the light emitting element unit 10b as shown in the waveform g4. .. The SW252 continues to output the voltage Vb having a voltage value of V1 during the period from time t4 to t5 when the clock signal CLK is H level. The light emitting element unit 10b emits light during the period from time t4 to t5 when the voltage value of the voltage Vb is V1. As a result, as shown in the waveform g8, the temperature of the heat storage layer 12 of the light emitting element unit 10b rises due to radiation, the temperature of the heat storage layer 12 reaches, for example, Ta, and the output of the voltage Vb changes to a predetermined value or less. After time t5, the temperature gradually decreases.

At the time t6 of the third rising edge of the clock signal CLK after the output of the control signal is started, the SW253 starts outputting the voltage Vc having a voltage value of V1 to the light emitting element unit 10c as shown in the waveform g5. .. The SW253 continues to output the voltage Vc having a voltage value of V1 during the period from time t6 to t7 when the clock signal CLK is H level. The light emitting element unit 10c emits light during the period from time t6 to t7 when the voltage value of the voltage Vc is V1. As a result, as shown in the waveform g9, the temperature of the heat storage layer 12 of the light emitting element unit 10c rises due to radiation, the temperature of the heat storage layer 12 reaches, for example, Ta, and the output of the voltage Vc changes to a predetermined value or less. After time t7, the temperature gradually decreases.

At the fourth rising time t8 of the clock signal CLK after the output of the control signal is started, the SW254 starts outputting the voltage Vd having a voltage value of V1 to the light emitting element unit 10d as shown in the waveform g6. .. The SW254 continues to output the voltage Vd having a voltage value of V1 during the period from time t8 to t9 when the clock signal CLK is H level. The light emitting element unit 10d emits light during the period from time t8 to t9 when the voltage value of the voltage Vd is V1. As a result, as shown in the waveform g10, the temperature of the heat storage layer 12 of the light emitting element unit 10d rises due to radiation, the temperature of the heat storage layer 12 reaches, for example, Ta, and the output of the voltage Vd changes to a predetermined value or less. After time t9, the temperature gradually decreases.

The operations of the SW251 and the light emitting element unit 10a at the time of the fifth rising edge of the clock signal CLK after the output of the control signal is started are the same as those of the times t2 to t3.
The operations of the SW252 and the light emitting element unit 10b at the time of the sixth rising edge of the clock signal CLK after the output of the control signal is started are the same as those of the times t4 to t5.
The operations of the SW253 and the light emitting element unit 10c at the time of the seventh rising edge of the clock signal CLK after the output of the control signal is started are the same as those of the times t6 to t7.
The operations of the SW254 and the light emitting element unit 10d at the time of the eighth rising edge of the clock signal CLK after the output of the control signal is started are the same as those of the times t8 to t9.

As described above, in the present embodiment, as shown in FIG. 7, the control unit (clock generation unit 21, temperature control unit 23, power supply unit 24, switch unit 25) has a plurality of light emitting element units (10a to 10d). The procedure includes a procedure of controlling one of a plurality of light emitting element units to sequentially emit light so that the remaining light emitting element units do not emit light when one of the light emitting element units is emitting light.

In the example shown in FIG. 7, an example in which each of the light emitting element units 10 is radiated twice during the period when the output of the control signal is started is shown, but the number of times of radiating is not limited to this. It may be once or more than three times.

FIG. 8 is a diagram showing an example of the temperature of the heat storage layer 12 when the light emitting element 1C is driven as shown in FIG. The figure shown in FIG. 8 shows the temperature of the heat storage layer 12 of the light emitting element 1C. As described with reference to FIG. 7, since the light emitting element units 10 are alternately radiated, the temperature accumulated in the heat storage layer 12 is not added, and the maximum value of the temperature of the heat storage layer 12 remains Ta. In FIG. 8, when the light emitting element unit 10a is continuously radiated at each timing of the clock signal CLK shown in FIG. 7, the temperature of the heat storage layer 12 is ΔT at time t11, so that the second radiation is performed. The temperature of the heat storage layer 12 drifts to ΔT + Ta. As a result, as shown in FIG. 4, the temperature of the heat storage layer 12 rises for each radiation. On the other hand, according to the present embodiment, since the plurality of light emitting element units 10 are radiated alternately, the maximum value of the temperature of the heat storage layer 12 remains Ta.
The time in the off state (non-radiating state) of the light emitting element unit 10 is set to be sufficiently longer than the time constant of heat dissipation.

The configuration of the light emitting element 1C shown in FIG. 5 is an example, and is not limited to this. For example, the light emitting element 1C may include two or more light emitting element units. For example, in the configuration shown in FIG. 5, when the light emitting element 1C includes two light emitting element units 10, for example, the light emitting element unit 10a and the light emitting element unit 10c, or the light emitting element unit 10b and the light emitting element unit 10d are arranged diagonally. It is preferable to prepare. The reason for this is that an arrangement that reduces the influence of heat accumulated in the heat storage layer 12 of the light emitting element unit 10 is preferable.
Further, the light emitting element unit 10 may include an infrared radiation layer 17 as in the second embodiment.

<Modification example>
Here, a modified example of the present embodiment will be described. The configuration of the light emitting element 1C is the same as that in FIG.
FIG. 9 is a block diagram showing a configuration example of the control device 2A for the light emitting element of the modified example according to the present embodiment. As shown in FIG. 9, the control device 2A of the light emitting element includes a clock generation unit 21A, an operation unit 22, a temperature control unit 23A, a power supply unit 24, a switch unit 25, a light emitting element 1C, a light receiving element 26, and a lock-in amplifier 27. To be equipped.

The clock generation unit 21A generates a clock signal CLK having a predetermined frequency, and outputs the generated clock signal to the switch unit 25, the temperature control unit 23A, and the lock-in amplifier 27.
In the temperature control unit 23A, the temperature of the heat storage layer 12 (FIG. 5) from the power supply unit 24 is Ta, Tb, Tc, Td during a period when the control signal has a predetermined magnitude or more according to the operation result output by the operation unit 22. The control signal, which is an instruction to output the voltage values (V1, V2, V3, V4), is output to the power supply unit 24 so as to be.
The power supply unit 24 supplies electric power having voltage values V1, V2, V3, and V4 to the switch unit 25 during the period when the temperature control unit 23A outputs the control signal.

In this way, since the voltage applied to each of the light emitting element units 10 is different, each of the light emitting element units 10 has a different temperature. As a result, the temperature of the light emitting element unit 10a becomes Ta, and the peak wavelength λ ₁ corresponding to the temperature Ta is emitted. The light emitting element unit 10b has a temperature of Tb and emits a peak wavelength λ ₂ corresponding to the temperature Tb. The light emitting element unit 10c has a temperature of Tc and emits a peak wavelength λ ₃ corresponding to the temperature Tc. The light emitting element unit 10d has a temperature of Td and emits a peak wavelength λ ₄ corresponding to the temperature Td. This is due to Planck's law that the peak wavelength λ differs depending on the temperature and the radiated intensity increases according to the temperature. The temperature target controlled by the temperature control unit 23A is a temperature corresponding to the wavelength of the substance to be detected.

As a result, the control device 2A of the light emitting element can radiate a plurality of wavelengths, so that a plurality of components contained in the gas can be detected. For example, as shown in FIG. 9, when the light emitting element 1C includes four light emitting element units 10, four wavelengths can be detected.

Next, an operation example of the control device 2A of the light emitting element will be described.
FIG. 10 is a diagram showing a timing chart of the control device 2A of the light emitting element of the modified example according to the present embodiment. In FIG. 10, the horizontal axis represents time, the vertical axis of waveforms g1 to g6 represents the level of each signal, and the vertical axis of waveforms g7 to g10 represents temperature. Further, the waveform g1 represents a control signal, the waveform g2 represents a clock signal CLK, the waveform g3 represents a voltage Va, the waveform g4 represents a voltage Vb, the waveform g5 represents a voltage Vc, and the waveform g6 represents a voltage Vd. Further, the waveform g7 is the temperature rise of the heat storage layer 12 of the light emitting element unit 10a, the waveform g8 is the temperature rise of the heat storage layer 12 of the light emitting element unit 10b, the waveform g9 is the temperature rise of the heat storage layer 12 of the light emitting element unit 10c, and the waveform g10 is. It represents the temperature rise of the heat storage layer 12 of the light emitting element unit 10d.

The clock generation unit 21A outputs the generated clock signal CLK as shown in the waveform g2 to the switch unit 25.
During the period from time t21 to t22, the temperature control unit 23A outputs a control signal in which the voltage value output by the power supply unit 24 is Ta as shown in the waveform g1.

During the period from time t21 to t22, SW251 starts outputting the voltage Va having a voltage value of V1 to the light emitting element unit 10a as shown in the waveform g3. The SW251 continues to output the voltage Va having a voltage value of V1 during the period from time t21 to t22 when the clock signal CLK is H level. The light emitting element unit 10a radiates during the period from time t21 to t22 when the voltage value of the voltage Va is V1. As a result, as shown in the waveform g7, the temperature of the heat storage layer 12 (FIG. 5) of the light emitting element unit 10a rises due to radiation, the temperature of the heat storage layer 12 reaches, for example, Ta, and the output of the voltage Va falls below a predetermined value. After the time t22 after the change, the temperature gradually decreases.

During the period from time t23 to t24, SW252 starts outputting the voltage Vb having a voltage value of V2 to the light emitting element unit 10b as shown in the waveform g4. In the example shown in FIG. 10, the voltage value V2 is larger than the voltage value V1. The SW252 continues to output the voltage Vb having a voltage value of V2 during the period from time t23 to t24 when the clock signal CLK is H level. The light emitting element unit 10b emits light during the period from time t23 to t24 when the voltage value of the voltage Vb is V2. As a result, as shown in the waveform g8, the temperature of the heat storage layer 12 of the light emitting element unit 10b rises due to radiation, the temperature of the heat storage layer 12 reaches, for example, Tb, and the output of the voltage Vb changes to a predetermined value or less. After time t24, the temperature gradually decreases.

During the period from time t25 to t26, SW253 starts outputting the voltage Vc having the voltage value V3 to the light emitting element unit 10c as shown in the waveform g5. In the example shown in FIG. 10, the voltage value V3 is larger than the voltage value V2. The SW253 continues to output the voltage Vc having a voltage value of V3 during the period from time t25 to t26 when the clock signal CLK is H level. The light emitting element unit 10c emits light during the period from time t25 to t26 when the voltage value of the voltage Vc is V3. As a result, as shown in the waveform g9, the temperature of the heat storage layer 12 of the light emitting element unit 10c rises due to radiation, the temperature of the heat storage layer 12 reaches, for example, Tc, and the output of the voltage Vc changes to a predetermined value or less. After time t26, the temperature gradually decreases.

During the period from time t27 to t28, SW254 starts outputting the voltage Vd having a voltage value of V4 to the light emitting element unit 10d as shown in the waveform g6. In the example shown in FIG. 10, the voltage value V4 is larger than the voltage value V3. The SW254 continues to output the voltage Vd having a voltage value of V4 during the period from time t27 to t28 when the clock signal CLK is H level. The light emitting element unit 10d emits light during the period from time t27 to t28 when the voltage value of the voltage Vd is V4. As a result, as shown in the waveform g10, the temperature of the heat storage layer 12 of the light emitting element unit 10d rises due to radiation, the temperature of the heat storage layer 12 reaches, for example, Td, and the output of the voltage Vd changes to a predetermined value or less. After time t28, the temperature gradually decreases.

FIG. 11 is a diagram showing an example of the temperature of the heat storage layer 12 when the light emitting element 1C is driven as shown in FIG. The figure shown in FIG. 11 shows the temperature of the heat storage layer 12 of the light emitting element 1C. As described with reference to FIG. 10, since the light emitting element units 10 are radiated alternately, the temperature accumulated in the heat storage layer 12 is not added, and the maximum temperature of the heat storage layer 12 is the maximum value at the time of the first radiation. Is Ta, the second radiation is Tb, the third radiation is Tc, and the fourth radiation is Td. The time in the off state (non-radiating state) of the light emitting element unit 10 is set to be sufficiently longer than the time constant of heat dissipation.
According to a modification of the present embodiment, by driving the light emitting element 1C as shown in FIG. 10, the amount of electric power can be changed for each light emitting element unit 10 and the emission peak wavelength can be changed. In addition, according to the modification of the present embodiment, NDIR gas measurement with a plurality of wavelengths or a wide band wavelength can be performed with a simple configuration.

As described above, in the present embodiment, as shown in FIG. 10, the control unit (clock generation unit 21A, temperature control unit 23A, power supply unit 24, switch unit 25) has a plurality of light emitting element units (10a to 10d). The procedure includes a procedure of controlling one of a plurality of light emitting element units to sequentially emit light so that the remaining light emitting element units do not emit light when one of the light emitting element units is emitting light.

In the example shown in FIG. 10, control signals are input to each of the light emitting element units 10 at equal intervals, but the present invention is not limited to this. Since the temperature rise of each of the heat storage layers 12 of each light emitting element unit 10 differs depending on the target temperature of each of the light emitting element units 10, the timing of outputting the control signals Ta to Td is set to such a temperature rise of the heat storage layer 12. The timing may be adjusted accordingly. For example, the interval between the control signals Ta and Tb is one clock signal CLK, the interval between the control signals Tb and Tc is two clock signals CLK, and the interval between the control signals Tc and Td is three clock signals CLK. The temperature control unit 23A may control the clock so as to be the same. As a result, the influence of the temperature drift between the heat storage layers 12 of the light emitting element unit 10 and the influence of the temperature drift in the light emitting element unit 10 can be further suppressed.

<Fourth Embodiment>
The light emitting element of the present embodiment further includes a temperature detection unit in addition to the configurations of the first to third embodiments.
FIG. 12 is a diagram showing a configuration example of the light emitting element 1D according to the present embodiment. FIG. 12A is a top view of the light emitting element 1D according to the present embodiment. FIG. 12B is a cross-sectional view taken along the line AA'of FIG. 12A of the light emitting device 1D according to the present embodiment.

As shown in FIGS. 12A and 12B, the light emitting element 1D includes a substrate 11, a heat storage layer 12, a heat generating resistor 13, wiring 14a, wiring 14b, a pad 15a, a pad 15b, and a temperature detection unit 18. A wiring 19a, a wiring 19b, a pad 20a, and a pad 20b are provided. The light emitting element 1D may include a protective film 16 (FIG. 1) or an infrared radiation layer 17 (FIG. 3) as in the first embodiment. The same reference numerals are used for those having the same functions as the light emitting element 1 and the light emitting element 1B, and the description thereof will be omitted.

The heat storage layer 12 is formed on the upper surface of the substrate 11. The heat generation resistor 13 is formed on the upper surface of the heat storage layer 12. The wiring 14a and the wiring 14b are formed by being connected to, for example, both ends of the heat generating resistor 13. Wiring 14a is connected to the pad 15a. Wiring 14b is connected to the pad 15b. The temperature detection unit 18 is formed on the upper surface of the heat storage layer 12 and in the vicinity of, for example, the side surface of the heat generation resistor 13. The wiring 19a and the wiring 19b are formed by being connected to, for example, both ends of the temperature detection unit 18. Wiring 19a is connected to the pad 20a. Wiring 19b is connected to the pad 20b.

The materials of the substrate 11, the heat storage layer 12, the heat generating resistor 13, the wiring 14a, the wiring 14b, the pad 15a, and the pad 15b are the same as those of the light emitting element 1.
The materials of the wiring 19a and the wiring 19b are the same as those of the wiring 14a and the wiring 14b.
The material of the pad 20a and the pad 20b is the same as that of the pad 15a and the pad 15b.

The temperature detection unit 18 is, for example, a thin film thermistor. The temperature detection unit 18 detects the ambient temperature including the temperature of the heat storage layer 12. The temperature detection unit 18 outputs the detected temperature information. The temperature detection unit 18 is provided so as not to come into contact with the heat generation resistor 13.

As shown in FIG. 13, the temperature detection unit 18 may further form a second heat storage layer 12b on the upper surface of the first heat storage layer 12a, and may form the temperature detection unit 18 on the upper surface thereof. ..
FIG. 13 is a diagram showing another configuration example of the light emitting device according to the present embodiment. FIG. 13A is a top view of the light emitting element 1E according to the present embodiment. FIG. 13B is a cross-sectional view taken along the line AA'of FIG. 13A of the light emitting device 1E according to the present embodiment.

As shown in FIGS. 13A and 13B, the light emitting element 1E includes a substrate 11, a first heat storage layer 12a, a second heat storage layer 12b, a heat generating resistor 13, wiring 14a, wiring 14b, and a pad. A 15a, a pad 15b, a temperature detection unit 18, a wiring 19a, a wiring 19b, a pad 20a, and a pad 20b are provided. The light emitting element 1E may include a protective film 16 (FIG. 1) or an infrared radiation layer 17 (FIG. 3) as in the first embodiment. The same reference numerals are used for those having the same functions as the light emitting element 1 and the light emitting element 1B, and the description thereof will be omitted.

The first heat storage layer 12a is formed on the upper surface of the substrate 11. The heat generation resistor 13 is formed on the upper surface of the first heat storage layer 12a. The wiring 14a and the wiring 14b are formed by being connected to, for example, both ends of the heat generating resistor 13. Wiring 14a is connected to the pad 15a. Wiring 14b is connected to the pad 15b. The second heat storage layer 12b is formed on the upper surface of the first heat storage layer 12a so as to cover at least a part of the heat generating resistor 13, the wiring 14a, and the wiring 14b. The temperature detection unit 18 is formed so as not to cover the heat generating resistor 13 on the upper surface of the second heat storage layer 12b. The wiring 19a and the wiring 19b are formed by being connected to, for example, both ends of the temperature detection unit 18. Wiring 19a is connected to the pad 20a. Wiring 19b is connected to the pad 20b.

The light emitting element may include a plurality of light emitting element units similar to those in the third embodiment. In this case, in FIG. 5, each of the four light emitting element units 10 may be configured as a light emitting element 1D or a light emitting element 1E. As described above, when the light emitting element includes a plurality of light emitting element units, it is sufficient that at least one light emitting element unit includes the temperature detection unit 18.

Next, an example of the control device 2A of the light emitting element that measures the wavelength of the measurement target by using the light emitting element 1D will be described.
FIG. 14 is a block diagram showing a configuration example of the light emitting element control device 2B according to the present embodiment. As shown in FIG. 14, the light emitting element control device 2B includes a clock generation unit 21B, an operation unit 22, a temperature control unit 23B, a power supply unit 24, a light emitting element 1D, a light receiving element 26, and a lock-in amplifier 27. The same reference numerals are used for the functional units having the same functions as the control device 2 (FIG. 9) of the light emitting element of the third embodiment, and the description thereof will be omitted.

The clock generation unit 21B generates a clock signal CLK having a predetermined frequency, and outputs the generated clock signal to the temperature control unit 23B and the lock-in amplifier 27.
The temperature control unit 23B receives the temperature of the heat storage layer 12 of the light emitting element 1D from the power supply unit 24 for a predetermined period based on the operation result output by the operation unit 22 and the temperature information output by the temperature detection unit 18 of the light emitting element 1D. Is output to the power supply unit 24 as an instruction to output the voltage value V2 so as to keep the temperature within a predetermined temperature.
The power supply unit 24 supplies electric power having a voltage value of V2 to the heat generating resistor 13 of the light emitting element 1D during the period when the temperature control unit 23B outputs the control signal.

According to the configuration shown in FIG. 14, drift can be suppressed by measuring the temperature at a steady state and controlling the electric power by feedback control.

In the example shown in FIG. 14, the case where there is one light emitting element has been described, but the present invention is not limited to this, and a plurality of light emitting element units similar to those in the third embodiment may be provided. In this case, the switch unit 25 (FIG. 9) may be connected between the power supply unit 24 and the light emitting element including the plurality of light emitting element units. When each of the plurality of light emitting element units includes the temperature detection unit 18, the temperature control unit 23B controls the electric power to the corresponding light emitting element unit by feedback control based on the output of each of the temperature detection units 18. You may try to suppress the drift with. Further, among the plurality of light emitting element units, for example, when one light emitting element unit includes a temperature detection unit 18, the temperature control unit 23B refers to the plurality of light emitting element units based on the output of one temperature detection unit 18. The drift may be suppressed by controlling the electric power by feedback control.
In this case, the control timing of the plurality of light emitting element units is the same as in FIG. 7 or FIG. Then, at each control timing, the temperature control unit 23B may drive each of the plurality of light emitting element units based on the result detected by the temperature detection unit 18 as described above.

A program for realizing the function of the temperature control unit 23 (or 23A, 23B) in the present invention is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read by the computer system. By executing this, the drive of the radiation of the light emitting element 1 (or 1B, 1C) may be controlled. The term "computer system" as used herein includes hardware such as an OS and peripheral devices. Further, the "computer system" shall also include a WWW system provided with a homepage providing environment (or display environment). Further, the "computer-readable recording medium" refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, or a CD-ROM, or a storage device such as a hard disk built in a computer system. Furthermore, a "computer-readable recording medium" is a volatile memory (RAM) inside a computer system that serves as a server or client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, it shall include those that hold the program for a certain period of time.

Further, the program may be transmitted from a computer system in which this program is stored in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the "transmission medium" for transmitting a program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. Further, the above program may be for realizing a part of the above-mentioned functions. Further, a so-called difference file (difference program) may be used, which can realize the above-mentioned functions in combination with a program already recorded in the computer system.

1,1A, 1B, 1C, 1D, 1E ... light emitting element, 2,2A, 2B ... light emitting element control device, 10,10a, 10b, 10c, 10d ... light emitting element unit, 11 ... substrate, 12 ... heat storage layer, 13 ... Heat-generating resistor, 14a, 14b ... Wiring, 15a, 15b ... Pad, 16 ... Protective film, 17 ... Infrared radiation zone, 18 ... Temperature detection unit, 21,21A, 21B ... Clock generation unit, 22 ... Operation unit, 23, 23A, 23B ... Temperature control unit, 24 ... Power supply unit, 25 ... Switch unit, 26 ... Light receiving element, 27 ... Lock-in amplifier

Claims (7)

A light emitting element in which a plurality of light emitting element units are arranged on one substrate without contacting each other, and each of the light emitting element units has a heat storage layer and a heat generating resistor.
One of the plurality of light emitting element units is sequentially emitted so as not to emit the remaining light emitting element units when one of the plurality of the light emitting element units is emitting light. The control unit to control and
Equipped with a,
The light emitting element is
With the board
N heat storage layers (where N is an integer of 2 or more) provided in contact with one surface side of the substrate, and each of the N heat storage layers is in contact with each other on one surface side of the substrate. With the heat storage layer provided without
Of the surfaces of the heat storage layer, N heat generation resistors are provided in contact with a surface side different from the surface in contact with the substrate, and each of the N heat generation resistors has N heat storage layers. Heat storage resistors provided on each surface side different from the surface in contact with the substrate,
Control device of a light emitting element Ru with a. The control device for a light emitting element according to claim 1, wherein the control unit drives each of the plurality of light emitting element units so that the wavelength at which the plurality of light emitting element units emit light is a predetermined wavelength. The control device for a light emitting element according to claim 1, wherein the control unit drives each of the plurality of light emitting element units so that each of the plurality of light emitting element units emits light at a predetermined wavelength. The control device for a light emitting element according to claim 3, wherein the control unit controls the light emission timing of each of the plurality of light emitting element units according to the wavelength at which each of the plurality of light emitting element units emits light. The light emitting element includes a temperature detection unit that detects the temperature of the own element.
The control device for a light emitting element according to claim 4, wherein the control unit drives each of the plurality of light emitting element units based on the temperature detected by the temperature detection unit. A substrate, a heat storage layer provided in contact with one surface side of the substrate, and a heat generating resistor provided in contact with a surface of the heat storage layer different from the surface in contact with the substrate. A light emitting element including a temperature detection unit that detects the temperature of the element, and
A control unit that drives the light emitting element and a control unit that drives the light emitting element based on the temperature detected by the temperature detection unit.
Equipped with a,
The heat storage layer is N (where N is an integer of 2 or more) heat storage layers provided in contact with one surface side of the substrate, and each of the N heat storage layers is one of the substrates. Provided on the surface side without contacting each other
The heat generation resistors are N heat generation resistors provided in contact with a surface of the heat storage layer that is different from the surface in contact with the substrate, and each of the N heat generation resistors is Each of the N heat storage layers is provided on a surface side different from the surface in contact with the substrate.
Light emitting element control device. A light emitting element in which a plurality of light emitting element units are arranged on one substrate without contacting each other. The light emitting element includes a substrate, a heat storage layer, and a heat generation resistor, and the heat storage layer is the said. N heat storage layers (where N is an integer of 2 or more) provided in contact with one surface side of the substrate, and each of the N heat storage layers is brought into contact with each other on one surface side of the substrate. The heat generation resistors are N heat generation resistors provided in contact with a surface of the heat storage layer different from the surface in contact with the substrate, and N heat generation resistors are provided. each resistor is provided on different side of the surface in contact with the N of the heat storage layer each of the substrate, the light emitting state of the light emitting element, each said light emitting unit is provided with the heating resistors and the heat storage layer It is a control method to control
One of the plurality of light emitting element units is sequentially generated so that the control unit does not emit the remaining light emitting element units when one of the plurality of the light emitting element units is emitting light. Procedure to control to emit light,
A method for controlling a light emitting element including.

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