JP2018195706A - Light-emitting device - Google Patents

Abstract

To provide a light-emitting device capable of independently flowing electric currents having respective optimum current values through first and second light-emitting elements which are opposite to each other in electric current-flowing direction and disposed on one substrate, and efficiently dissipating heat generated in first and second light-emitting elements in a limited space of the light-emitting device.SOLUTION: A light-emitting device comprises: a first light-emitting element 1 having a first face 1a including an anode element electrode 1d and a second face 1b including a cathode element electrode 1e; and a second light-emitting element 2 having a first face 2a including a cathode element electrode 2d and a second face 2b including an anode element electrode 2e. The cathode element electrode 1e of the second face 1b of the first light-emitting element 1 is electrically mounted on a first common electrode 4a disposed on a first face 3a of a substrate 3, and the anode element electrode 2e of the second face 2a of the second light-emitting element 2 is electrically mounted on the first common electrode 4a of the substrate 1. The first common electrode 4a disposed on the first face 3a of the substrate 3 is connected with a second common electrode 4b disposed on a second face 3b of the substrate 3.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a light emitting device in which a plurality of light emitting elements are arranged on one substrate.

  There exists a light emitting diode (LED) element as a light emitting element. A light emitting device having a light emitting element is used in, for example, a mobile terminal such as a smartphone, a display device, and a lighting fixture. A light emitting device having a light emitting element is used as, for example, a flash light source for photographing. In addition, light-emitting devices having light-emitting elements are used in various display devices as light sources for backlights. Furthermore, a light emitting device having a light emitting element is also mounted on an indoor lighting fixture or an outdoor lighting fixture. In recent years, a light-emitting device having a light-emitting element is used as a light source for an in-vehicle lamp or a projector that requires high luminance. Furthermore, lighting fixtures and display devices using LED elements having different peak wavelengths have been proposed. Furthermore, a light-emitting device including an infrared LED element that is used in electronic devices including a smartphone, a tablet terminal, and a PC has also been proposed. For example, a light emitting device including an infrared LED element can collect necessary information by irradiating an object with infrared light. As an example, a light emitting device including an infrared LED element is used for the purpose of biometric authentication. In such a light emitting device, infrared LED elements having different peak wavelengths may be arranged on one substrate.

  Patent Document 1 discloses a light emitting device in which LED chips having different wavelengths are arranged on a common electrode. One bonding wire is connected to the first LED chip. At least two or more bonding wires are connected to the upper surface of the second LED chip. At least two or more bonding wires are connected to the upper surface of the third LED chip.

Japanese Patent No. 3476611 (FIGS. 1 and 4)

  By the way, the LED element arrange | positioned on a board | substrate may be restricted by the element maker in the mounting direction to a board | substrate. For example, in the case of an infrared LED element, the lower surface of the infrared LED element is mounted on one electrode of the substrate. It is conceivable that one wire bonding is made on the upper surface of the infrared LED element, one end of the metal wire is connected to the upper surface of the LED element, and the other end of the metal wire is connected to another electrode of the substrate. However, there is a first infrared LED element in which an anode electrode is positioned on the upper surface where wire bonding can be performed and a cathode electrode is positioned on the lower surface. There is also a second infrared LED element in which a cathode electrode is located on the upper surface where wire bonding can be applied and an anode electrode is located on the lower surface. The first infrared LED element has a first peak wavelength, the second infrared LED element has a second peak wavelength, and the first peak wavelength and the second peak wavelength are different from each other. There are several things to consider when two light emitting elements having different peak wavelengths are mounted on one substrate to form an infrared light emitting device. In the infrared LED element in which the anode electrode is positioned on the upper surface of the infrared LED element and the infrared LED element in which the cathode electrode is positioned on the upper surface of the infrared LED element, the current flows in opposite directions. In addition, the first light emitting element having the first peak wavelength needs to pass a current having a first current value necessary for driving the first light emitting element, and the second light emitting element having the second peak wavelength is supplied to the first light emitting element. Needs to pass a current of a second current value necessary for driving the second light emitting element. The first current value and the second current value are different from each other, and the direction in which the current flows is opposite as described above.

  Therefore, it is necessary to propose a structure that allows the first current value to flow through the first light emitting element and the second current value to flow through the second light emitting element independently in the light emitting device as described above. Further, when the light emitting device includes a plurality of light emitting elements, heat generated from each light emitting element also increases. Therefore, how efficiently the heat generated from the first light emitting element when the first current value is passed through the first light emitting element and the heat generated from the second light emitting element when the second current value is passed through the second light emitting element. It is necessary to consider whether to dissipate heat.

  Therefore, the light-emitting device of the present invention has a first light-emitting element and a second light-emitting element in which the direction of current flow is reversed, and the first light-emitting element and the second light-emitting element are electrically mounted on the common electrode, In addition, a structure is proposed in which the first current value can be independently supplied to the first light emitting element and the second current value can be independently supplied to the second light emitting element. In addition, the light emitting device of the present invention allows the first current value to flow through the first light emitting element and the second current value to flow through the second light emitting element independently from each other, and from the first light emitting element and the second light emitting element. A heat dissipation structure for efficiently radiating generated heat through a common electrode in a limited space of a light emitting device is proposed.

  In a light emitting device according to an embodiment of the present invention, a first surface includes an anode element electrode, a second surface includes a cathode element electrode, a first surface includes a cathode element electrode, and a second surface. Has a second light emitting element including an anode element electrode. The cathode element electrode on the second surface of the first light emitting element is electrically mounted on the first common electrode disposed on the first surface of the substrate, and the anode element electrode on the second surface of the second light emitting element is formed on the substrate. The first common electrode is electrically mounted. The first common electrode disposed on the first surface of the substrate is connected to the second common electrode disposed on the second surface of the substrate.

  In the light emitting device according to the embodiment of the present invention, the first surface of the substrate has two or more upper surface small electrodes having a smaller area than the first common electrode. In the light emitting device according to the embodiment of the present invention, the cathode element electrode on the second surface of the first light emitting element is bonded onto the first common electrode of the substrate by the conductive die bond paste, and the second light emitting element The anode element electrode on the second surface is bonded onto the first common electrode of the substrate by a conductive die bond paste.

  Furthermore, it is proposed that an electronic apparatus according to the present invention includes the light emitting device according to the present invention and a motherboard including a first electrode on which the second common electrode of the substrate of the light emitting device according to the present invention is mounted. . The second common electrode of the light emitting device may be electrically and thermally connected to the first electrode of the mother board, and the first electrode of the mother board may have a larger area than the second common electrode of the light emitting device.

  According to the light emitting device according to the embodiment of the present invention, the first light emitting element and the second light emitting element in which the direction of current flow are reversed are electrically disposed on the first common electrode disposed on the first surface of the substrate. Although mounted, currents having different current values can be allowed to flow through the first light-emitting element and the second light-emitting element. In addition, according to the light emitting device according to the embodiment of the present invention, the first light emitting element and the second light emitting element are disposed in a limited space, and the first common electrode and the second common electrode disposed on the substrate are used for the first. Heat generated from the light emitting element and the second light emitting element can be efficiently radiated out of the light emitting device.

  Further, according to the light emitting device of the present invention, the first common electrode disposed on the first surface of the substrate has a larger area than the upper surface small electrode having two or more on the first surface of the substrate. In addition, the cathode element electrode on the second surface of the first light emitting element can be adhered on the first common electrode of the substrate by a conductive die bond paste, and the anode element electrode on the second surface of the second light emitting element is The conductive die bond paste can be bonded onto the first common electrode of the substrate. Therefore, heat generated from the first light emitting element and the second light emitting element can be efficiently radiated in a limited space of the light emitting device.

  According to the electronic device of the present invention, the second common electrode of the light emitting device is electrically and thermally connected to the first electrode of the mother board, and the first electrode of the mother board is connected to the second common electrode of the light emitting device. Also, the area can be set large. Therefore, heat generated from the light emitting device can be efficiently radiated to the outside of the light emitting device through the first electrode of the motherboard.

It is a top view of the light-emitting device concerning a 1st embodiment of the present invention. It is II-II sectional drawing of the top view shown in FIG. 1 is a circuit diagram of a light emitting device according to a first embodiment of the present invention. It is a top view of the light-emitting device concerning a 2nd embodiment of the present invention. It is a circuit diagram of the light-emitting device which concerns on 2nd Embodiment of this invention. It is a top view of the light-emitting device concerning a 3rd embodiment of the present invention. It is VII-VII sectional drawing of the top view shown in FIG. It is sectional drawing which has arrange | positioned the light-emitting device of this invention to the motherboard of an electronic device.

  Hereinafter, embodiments of a light emitting device according to the present invention will be described in detail with reference to the drawings. The drawings schematically represent the light emitting device of the present invention. These actual dimensions and dimension ratios do not necessarily match the dimensions and dimension ratios in the drawings. In addition, duplicate descriptions may be omitted as appropriate, and the same symbols may be assigned to the same members. Furthermore, it should be noted that the technical scope of the present invention is not limited to the embodiments described below, but extends to the invention described in the claims and equivalents thereof.

(First embodiment)
1 and 2 show a light emitting device 100 according to a first embodiment of the present invention. The light emitting device 100 includes a first light emitting element 1 and a second light emitting element 2. The first light emitting element 1 includes a first surface 1a, a second surface 1b opposite to the first surface 1a, and a peripheral side surface 1c between the periphery of the first surface 1a and the periphery of the second surface 1b. Have. The first surface 1a of the first light emitting element 1 includes an anode element electrode 1d, and the second surface 1b of the first light emitting element 1 includes a cathode element electrode 1e. The second light emitting element 2 includes a first surface 2a, a second surface 2b opposite to the first surface 2a, and a peripheral side surface 2c between the periphery of the first surface 2a and the periphery of the second surface 2b. Have. The first surface 2a of the second light emitting element 2 includes a cathode element electrode 2d, and the second surface 2b of the second light emitting element 2 includes an anode element electrode 2e.

  Furthermore, the light emitting device 100 includes a substrate 3. The substrate 3 has a first surface 3a and a second surface 3b opposite to the first surface 3a. The substrate 3 includes a first common electrode 4 a disposed on the first surface 3 a of the substrate 3 and a second common electrode 4 b disposed on the second surface 3 b of the substrate 3. The cathode element electrode 1 e on the second surface 1 b of the first light emitting element 1 is electrically mounted on the first common electrode 4 a of the substrate 3. The anode element electrode 2 e on the second surface 2 b of the second light emitting element 2 is electrically mounted on the first common electrode 4 a of the substrate 3. The first common electrode 4a and the second common electrode 4b of the substrate 3 are connected.

  In the light emitting device 100, two or more first light emitting elements 1 as the first light emitting elements 1 and two or more second light emitting elements 2 as the second light emitting elements 2 may be arranged. The two or more first light emitting elements 1 and the two or more second light emitting elements 2 are all mounted on the first common electrode 4 a disposed on the first surface 3 a of the substrate 3.

  The first surface 3a of the substrate 3 has two or more upper surface small electrodes 5 and 7 having a smaller area than the first common electrode 4a. In FIG. 1, as an example, four first light emitting elements 1, four second light emitting elements 2, four first light emitting elements 1, and four second light emitting elements 2 are all mounted on a first common electrode 4 a. 1 shows a light emitting device 100 having a substrate 3 including. In addition, the number of the 1st light emitting elements 1 and the number of the 2nd light emitting elements 2 are not this limitation, and can be selected suitably.

  In FIG. 1, the second surfaces 1 b of the four first light emitting elements 1 are mounted on the first common electrode 4 a disposed on the first surface 3 a of the substrate 3 by a conductive die bond paste. . The second surfaces 2b of the four second light emitting elements 2 are mounted on the first common electrode 4a disposed on the first surface 3a of the substrate 3 by a conductive die bond paste.

  Specifically, the cathode element electrode 1e on the second surface 1b of the first light emitting element 1 is bonded onto the first common electrode 4a of the substrate 3 with a conductive die bond paste. Further, the anode element electrode 1 d on the first surface 1 a of the first light emitting element 1 is electrically connected to one of the first upper surface small electrodes 5 a by the metal wire 6. The anode element electrode 2e on the second surface 2b of the second light emitting element 2 is bonded onto the first common electrode 4a of the substrate 3 by a conductive die bond paste. Further, the cathode element electrode 2 d on the first surface 2 a of the second light emitting element 2 is electrically connected to one of the second upper surface small electrodes 7 a by the metal wire 8.

  The first surface 3a of the substrate 3 has two or more upper surface small electrodes 5 and 7 having a smaller area than the first common electrode 4a. The second surface 3b of the substrate 3 has two or more lower surface small electrodes 5 'and 7' having a smaller area than the second common electrode 4b.

  The first surface 3 a of the substrate 3 has a first common electrode 4 a on which the first light emitting element 1 and the second light emitting element 2 are disposed. The second surface 3b of the substrate 3 has a second common electrode 4b. As shown in FIG. 2, the first common electrode 4a may be electrically connected to the second common electrode 4b through the through hole 4c. Furthermore, as shown in FIGS. 6 and 7, the first common electrode 4 a disposed on the first surface 3 a of the substrate 3 passes on the side surface of the substrate 3 and extends to the second surface 3 b of the substrate 3. The second common electrode 4b may be integrally connected.

  The area of the first shared electrode 4a may be set larger than the sum of the areas of the two or more first upper surface small electrodes 5a and the two or more second upper surface small electrodes 7a.

  In the light emitting device 100 shown in FIGS. 1 and 2, the first surface 3a of the substrate 3 further includes four first upper surface small electrodes 5a. Each first upper surface small electrode 5 a corresponds to each of the four first light emitting elements 1, and the four first upper surface small electrodes 5 a can be arranged along the left edge of the substrate 3. Each first upper surface small electrode 5a is arranged up to the vicinity of the first light emitting element 1 while maintaining electrical insulation with the first common electrode 4a. The anode element electrode 1d on the first surface 1a of the first light emitting element 1 is electrically connected by wire bonding a metal wire 6 to the first upper surface small electrode 5a. The first common electrode 4 a has a larger area than each of the four first upper surface small electrodes 5 a provided on the substrate 3. Further, each of the first upper surface small electrodes 5a is electrically connected to the first lower surface small electrode 5c provided on the second surface 3b of the substrate 3 through the through hole 5b.

  The first surface 3a of the substrate 3 further includes four second upper surface small electrodes 7a. Each of the second upper surface small electrodes 7 a corresponds to each of the four second light emitting elements 2, and the four second upper surface small electrodes 7 a can be arranged along the right edge of the substrate 3. The second upper surface small electrode element 7a is disposed up to the vicinity of the second light emitting element 2 while maintaining electrical insulation with the first common electrode 4a. The cathode element electrode 2d on the first surface 2a of the second light emitting element 2 is electrically connected by wire bonding a metal wire 8 to the second upper surface small electrode 7a. The first common electrode 4 a has a larger area than each of the four second upper surface small electrodes 7 a provided on the substrate 3. Each of the second upper surface small electrodes 7a is electrically connected to the second lower surface small electrode 7c provided on the second surface 3b of the substrate 3 through the through hole 7b.

  FIG. 3 shows a circuit configuration of the light emitting device 100 according to the first embodiment. The anode element electrodes 1d of the four first light emitting elements 1 are connected to the first current control circuit 9a. The first current control circuit 9a is connected to the positive common power supply + V. On the other hand, each cathode element electrode 2d of the four second light emitting elements 2 is connected to the second current control circuit 9b. The second current control circuit 9b is connected to the negative common power source -V. The voltage values of the positive common power source + V and the negative common power source −V may be the same or different in absolute value. For example, when the positive common power supply is set to + 3V, the negative common power supply may be set to -3V. Moreover, you may set to minus volt | bolt values other than -3V. The first common electrode 4a may be connected to the ground on the external circuit board. At this time, the first common electrode 4a becomes 0V as a reference voltage.

  Due to the potential difference between the positive common power supply + V and the reference voltage 0 V, the current controlled by the first current control circuit 9 a flows through the first current control circuit 9 a and the first light emitting element 1, and the first light emitting element 1 emits light. .

  Due to the potential difference between the reference voltage 0V and the negative common power source −V, the current controlled by the second current control circuit 9b flows through the second light emitting element 2 and the second current control circuit 9b. Emits light.

  Thus, by providing a potential difference between the positive common power source + V and the negative common power source −V and using the first common electrode 4a as a reference voltage, the first light emitting element 1 and the second light emitting element 2 are used. Current flows through Therefore, the first light emitting element 1 and the second light emitting element 2 having different mounting directions can emit light simultaneously on the same substrate 3. In addition, the currents flowing in the first light-emitting element 1 and the second light-emitting element 2 having different peak wavelengths are controlled independently by the first current control circuit 9a and the second current control circuit 9b, respectively, so Two currents with different current values can flow.

  In the light emitting device according to the present embodiment, the first common electrode 4 a occupies a large area on the first surface 3 a of the substrate 3. Therefore, the heat generated from the first light emitting element 1 and the second light emitting element 2 can be efficiently radiated by the first common electrode 4a. The first common electrode 4a is electrically connected to the second common electrode 4b disposed on the second surface 3b of the substrate 3 through the through hole 4c. Therefore, the heat generated from the first light emitting element 1 and the second light emitting element 2 is also dissipated in the second common electrode 4b through the first common electrode 4a and the through hole 4c. In this way, the first common electrode 4a and the second common electrode 4b constitute a heat dissipation path. In addition, since the second common electrode 4b occupies a large area on the second surface 3b of the substrate 3, heat can be efficiently radiated also in the second common electrode 4b.

(Second Embodiment)
FIG. 4 shows a light emitting device 200 according to the second embodiment of the present invention. As in the first embodiment, the light-emitting device 200 according to this embodiment includes two or more first light-emitting elements 1, two or more second light-emitting elements 2, and the first light-emitting element 1 and the second light-emitting element 2. Is provided with a single substrate 3. Four first light emitting elements 1 are arranged on the left half of the first surface 3 a of the substrate 3, and three second light emitting elements 2 are arranged on the right half of the first surface 3 a of the substrate 3. In this embodiment, one thermistor 10 is provided at the center of the first surface 3 a of the substrate 3. The thermistor 10 includes a bottom element electrode 10a and a top element electrode 10b. The bottom element electrode 10a is electrically connected to the first common electrode 4a provided in a large area on the first surface 3a of the substrate 3 by a die bond paste. The upper surface element electrode 10 b is electrically connected to one of the second upper surface small electrodes 7 a provided on the first surface 3 a of the substrate 3 by wire bonding a metal wire 13. Since it is connected to the first common electrode 4 a, the temperature on the first common electrode 4 a can be monitored by the thermistor 10. Effective temperature correction can be performed by the thermistor 10.

  FIG. 5 shows a circuit configuration of the light emitting device 200. As in the first embodiment, the anode element electrodes 1d of the four first light emitting elements 1 are connected to the first current control circuit 9a. The first current control circuit 9a is connected to the positive common power supply + V. On the other hand, each cathode element electrode 2d of the three second light emitting elements 2 is connected to the second current control circuit 9b. The second current control circuit 9b is connected to the negative common power source -V. The voltage values of the positive common power source + V and the negative common power source −V may be the same or different in absolute value. The first common electrode 4a may be connected to the ground on the external circuit board. At this time, the first common electrode 4a becomes 0V as a reference voltage.

  The light emitting device 200 includes an LED controller circuit 11. In the LED controller circuit 11, two CTRs 11a and 11b are defined. One CTR 11a is connected to the first current control circuit 9a, and the other CTR 11b is connected to the second current control circuit 9b. One end of the upper surface element electrode 10b of the thermistor 10 is directly connected to the resistor 12 connected to the signal system power supply VCC. As a result, the divided voltage Vt of the resistor 12 and the thermistor 10 is fed back to the LED controller circuit 11 as temperature information. The LED controller circuit 11 controls the first current control circuit 9a and the second current control circuit 9b in accordance with the value of the divided voltage Vt.

  As described above, the light emitting device 200 according to this embodiment includes the thermistor 10. By using the thermistor 10 as a temperature detection sensor, it is possible to accurately grasp the temperature of the junction that is the light emitting portion of each light emitting element. Therefore, temperature correction can be included when the currents flowing through the first light emitting element 1 and the second light emitting element 2 having different peak wavelengths are controlled independently by the first current control circuit 9a and the second current control circuit 9b. Two different current values suitable for each light emitting element can be supplied.

(Third embodiment)
6 and 7 show a light emitting device 300 according to a third embodiment of the present invention. The first common electrode 4a disposed on the first surface 3a of the substrate 3 passes through the side surface of the substrate 3, extends to the second surface 3b of the substrate 3, and is integrally connected to the second common electrode 4b. . Note that the light-emitting device 300 of this embodiment is different from the light-emitting device 100 according to the first embodiment in this respect. In the light emitting device 100 according to the first embodiment, the first common electrode 4a disposed on the first surface 3a of the substrate 3 and the second common electrode 4b disposed on the second surface 3b of the substrate 3 have a plurality of through holes 4c. It is connected with. Except for this point, the light-emitting device 100 according to the first embodiment and the light-emitting device 300 according to the third embodiment may have the same configuration. Accordingly, parts that may have the same configuration are denoted by the same reference numerals in the drawings, and description of the third embodiment that overlaps with the light emitting device 100 of the first embodiment is omitted.

  In the light emitting devices 100, 200, and 300 according to the embodiments of the present invention, when the first light emitting element 1 is an infrared light emitting element, the peak wavelength is, for example, a wavelength of less than 1000 nm. Moreover, when the 2nd light emitting element 2 is an infrared light emitting element, a peak wavelength is a wavelength of 1000 nm or more, for example.

  The light emitting devices 100, 200, and 300 according to the embodiments of the present invention can be used in various electronic devices. For example, FIG. 8 shows an electronic device 20 including the light emitting device 100 according to the first embodiment and a mother board 21 on which the light emitting device 100 is arranged. As the electronic device 20, there are various display devices using a mobile terminal such as a smartphone or a light emitting device. The electronic device 20 includes a lighting fixture such as an in-vehicle lamp or a projector.

  The first electrode 22 is disposed on the upper surface 21 a of the mother board 21, and the second common electrode 4 b of the light emitting device 100 is mounted on the first electrode 22. The first electrode 22 has a larger area than the second common electrode 4b of the light emitting device 100, and is electrically and thermally connected to the second common electrode 4b. Therefore, the heat generated from the light emitting device 100 can be efficiently radiated by the first electrode 22 of the mother board 21. Note that the first electrode 22 of the mother board 21 may be electrically connected to the ground.

DESCRIPTION OF SYMBOLS 1 1st light emitting element 1a 1st surface of 1st light emitting element 1b 2nd surface of 1st light emitting element 1c Peripheral side surface of 1st light emitting element 1d Anode element electrode of 1st light emitting element 1e Cathode element electrode 2 of 1st light emitting element 2nd light emitting element 2a 1st surface of 2nd light emitting element 2b 2nd surface of 2nd light emitting element 2c Peripheral side surface of 2nd light emitting element 2d Cathode element electrode of 2nd light emitting element 2e Anode element electrode of 2nd light emitting element 3 Substrate 3a First surface of substrate 3b Second surface of substrate 4a First common electrode 4b Second common electrode 4c Through hole 5 Upper surface small electrode 5a First upper surface small electrode 5b, 7b Through hole 5c First lower surface small electrode 6, 8, 13 Metal wire 7 Lower surface small electrode 7a Second upper surface small electrode 7c Second lower surface small electrode 9a First current control circuit 9b Second current control circuit 10 Thermistor 10a Bottom surface element electrode 10b Upper surface element electrode 0c thermistor terminal 11a one CTR
11b The other CTR
DESCRIPTION OF SYMBOLS 12 Resistor 20 Electronic device 21 Mother board 21a Upper surface of motherboard 22 1st electrode of motherboard upper surface 100,200,300 Light-emitting device

Claims (14)

A first light emitting element comprising: a first surface; a second surface opposite to the first surface; and a peripheral side surface between a peripheral edge of the first surface and a peripheral edge of the second surface. A first light emitting element including an anode element electrode and a second surface of the first light emitting element including a cathode element electrode;
A second light emitting element having a first surface, a second surface opposite to the first surface, and a peripheral side surface between a peripheral edge of the first surface and a peripheral edge of the second surface. A second light emitting element including a cathode element electrode and a second surface of the second light emitting element including an anode element electrode;
A substrate having a first surface and a second surface opposite to the first surface, wherein the first common electrode is disposed on the first surface of the substrate, and the second surface is disposed on the second surface of the substrate. A substrate having a common electrode, and
The cathode element electrode on the second surface of the first light emitting element is electrically mounted on the first common electrode of the substrate, and the anode element electrode on the second surface of the second light emitting element 2 is on the first common electrode of the substrate. Is electrically mounted on the
The light emitting device, wherein the first common electrode and the second common electrode of the substrate are connected. As the first light emitting element, two or more first light emitting elements;
The light emitting device according to claim 1, further comprising two or more second light emitting elements as the second light emitting elements.   The light emitting device according to claim 1, wherein the first surface of the substrate has two or more upper surface small electrodes having an area smaller than that of the first common electrode.   The light emitting device according to claim 1, wherein the second surface of the substrate has two or more lower surface small electrodes having a smaller area than the second common electrode. The first surface of the substrate has four or more upper surface small electrodes having a smaller area than the first common electrode,
The light emitting device according to claim 1, wherein the upper surface small electrode includes two or more first upper surface small electrodes and two or more second upper surface small electrodes. The upper surface of the substrate has two or more first upper surface small electrodes,
The cathode element electrode on the second surface of the first light emitting element is adhered onto the first common electrode of the substrate by a conductive die bond paste,
The light emitting device according to claim 1, wherein the anode element electrode on the first surface of the first light emitting element is electrically connected to one of the first upper surface small electrodes by a metal wire. The upper surface of the substrate has two or more second upper surface small electrodes,
The anode element electrode on the second surface of the second light emitting element is adhered onto the first common electrode of the substrate by a conductive die bond paste,
The light emitting device according to claim 1, wherein the cathode element electrode on the first surface of the second light emitting element is electrically connected to one of the second upper surface small electrodes by a metal wire.   The light emitting device according to claim 1, wherein the first common electrode is electrically connected to the second common electrode via one or more through holes.   The first common electrode disposed on the first surface of the substrate passes through the side surface of the substrate, extends to the second surface of the substrate, and is integrally connected to the second common electrode. Light emitting device.   The light emitting device according to claim 1, wherein the peak wavelength of the first light emitting element and the peak wavelength of the second light emitting element are different from each other.   The light emitting device according to claim 10, wherein the peak wavelength of the first light emitting element is less than 1000 nm, and the peak wavelength of the second light emitting element is 1000 nm or more.   The light emitting device according to claim 1, further comprising a thermistor mounted on the first common electrode. A light emitting device according to claim 1;
A motherboard including a first electrode on which a second common electrode of a light emitting device is mounted,
The second common electrode of the light emitting device is electrically and thermally connected to the first electrode of the motherboard, and the first electrode of the motherboard has a larger area than the second common electrode of the light emitting device.   The electronic device according to claim 13, wherein the first electrode of the motherboard is electrically connected to the ground.

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