CN114183724A

CN114183724A - Lamp unit and vehicle lamp

Info

Publication number: CN114183724A
Application number: CN202110947467.7A
Authority: CN
Inventors: 前野雄壮
Original assignee: Koito Manufacturing Co Ltd
Current assignee: Koito Manufacturing Co Ltd
Priority date: 2020-09-15
Filing date: 2021-08-18
Publication date: 2022-03-15
Also published as: JP7444744B2; JP2022048556A

Abstract

Provided are a lamp unit and a vehicle lamp, wherein the setting of a light beam obtained by a simple structure can be changed even if an LED chip and an LDM are shared. A lamp unit is provided with: a light emitting unit in which a plurality of light emitting elements are connected in series by an inter-light emitting element wiring; a wiring substrate on which a wiring pattern (45) is formed; in a first light emitting element (42a) connected to the anode side, any one of a first anode electrode (46a), a first intermediate electrode (46b) and a first cathode electrode (46c) is electrically connected to a wiring pattern (45) other than the inter-light emitting element wiring in an alternative manner, and in a second light emitting element (42b) connected to the cathode side, any one of a second cathode electrode (46c), a second intermediate electrode (46b) and a second anode electrode (46a) is electrically connected to a wiring pattern (45) other than the inter-light emitting element wiring in an alternative manner.

Description

Lamp unit and vehicle lamp

Technical Field

The present invention relates to a lamp unit and a vehicle lamp, and more particularly to a lamp unit and a vehicle lamp in which a plurality of light emitting elements are connected in series and mounted on a wiring board.

Background

In recent years, vehicular lamps such as headlamps using Light Emitting Diodes (LEDs) as Light sources have become widespread. In a vehicle lamp using LEDs, a plurality of LED chips are connected in series as a light emitting portion and mounted on a wiring board, and a current is supplied from an LDM (LED Driver Module) to the plurality of LED chips, thereby obtaining a required light amount (see, for example, patent document 1).

In such a vehicle lamp, LED chips having the same characteristics are generally used as the plurality of LED chips. Since the current value flowing through the plurality of LEDs connected in series is common, the amount of light corresponding to the number of LED chips is obtained with reference to the amount of light emitted by one LED chip.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2020 and 021542

Disclosure of Invention

Problems to be solved by the invention

Fig. 10 is an equivalent circuit diagram showing a light emitting section used in a conventional lamp unit, where fig. 10(a) shows a case where four LED chips are connected in series, and fig. 10(b) shows a case where five LED chips are connected in series. In the example shown in fig. 10(a), as an example, when a 500 lumen light beam is obtained with a current of 1.4A in one LED chip, a total of 2000 lumens of light beam can be obtained with a current of 1.4A in four LED chips connected in series. In the example shown in fig. 10(b), five LED chips having the same characteristics are connected in series, whereby a total light beam of 2500 lumens can be obtained at a current of 1.4A.

In the vehicle lamp, a required light beam differs depending on national or regional regulations, insurance applicable conditions, and the like. Therefore, in order to obtain a desired luminous flux, it is necessary to individually set the number of LEDs of the light emitting section according to the area of the vehicle in use, or to change the current value for driving the LED chip according to the area. When the specification of the light emitting unit is changed by the area in this way, not only the management cost of the components increases, but also the setting of the LDM needs to be changed, which is not preferable.

Table 1 shows the number of LED chips used for low beam and high beam, and the beam ratio of the low beam light distribution and the high beam light distribution in the total beam of the vehicle lighting device.

[ Table 1]

As shown in No.1 of table 1, when two LED chips were used as the light emitting portions for the low beam and the high beam, respectively, each LED chip obtaining a luminous flux of 500 lumens, the luminous fluxes obtained were 1000 lumens, and the luminous flux ratio for the low beam was 50%. As shown in No.2, when three LED chips are used as the low-beam light emitting part and one LED chip is used as the high-beam light emitting part, the obtained luminous fluxes are 1500 lumens and 500 lumens, respectively, and the luminous flux ratio for the low beam is 75%. As shown in No.3, when each of the LED chips for obtaining a luminous flux of 1000 lumens was used and one LED chip was used as each of the light emitting portions for the low beam and the high beam, the luminous flux obtained was 1000 lumens, and the luminous flux ratio for the low beam was 50%.

The ratio of the luminous flux obtained from the low-beam light emitting part and the high-beam light emitting part is preferably such that the low-beam light is 1000 lumens or more and 55 to 70%. However, as shown in table 1, if the number of LED chips used for the light emitting section is reduced in order to increase the light flux obtained by one LED chip, it is difficult to realize the beam ratio for the low beam and the high beam. In order to realize the beam ratio by the number of LED chips shown in table 1, it is necessary to change the current value supplied from the LDM to the low beam light emitting portion and the high beam light emitting portion, which makes the control by the LDM complicated.

The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a lamp unit and a vehicle lamp that can change the setting of a light flux obtained by a simple configuration even when an LED chip and an LDM are shared.

Means for solving the problems

In order to solve the above problem, a lamp unit according to the present invention includes: a light emitting unit in which a plurality of light emitting elements are connected in series by an inter-light emitting element wiring; a wiring board on which a wiring pattern for supplying power to the light emitting section is formed; the light-emitting element is formed by overlapping a first light-emitting layer and a second light-emitting layer in a lamination direction, and includes: a cathode electrode connected to a cathode side of the first light-emitting layer; an intermediate electrode connected between the first light-emitting layer and the second light-emitting layer; an anode electrode connected to the anode side of the second light-emitting layer; in a first light emitting element connected to an anode-most side among the plurality of light emitting elements, any one of a first anode electrode, a first intermediate electrode, and a first cathode electrode is electrically connected to the wiring pattern other than the inter-light emitting element wiring, and in a second light emitting element connected to a cathode-most side among the plurality of light emitting elements, any one of a second cathode electrode, a second intermediate electrode, and a second anode electrode is electrically connected to the wiring pattern other than the inter-light emitting element wiring.

In the lamp unit of the present invention, the light emitting element is formed by overlapping the first light emitting layer and the second light emitting layer in the stacking direction, the first light emitting element is electrically connected to the wiring pattern in an alternative manner to any one of the first anode electrode, the first intermediate electrode, and the first cathode electrode, and the second light emitting element is electrically connected to the wiring pattern in an alternative manner to any one of the second cathode electrode, the second intermediate electrode, and the second anode electrode.

In one embodiment of the present invention, one or more other light-emitting elements are connected in series between the first light-emitting element and the second light-emitting element, and the intermediate electrode and the wiring pattern are insulated from each other in the other light-emitting elements.

In one aspect of the present invention, the plurality of light-emitting units include a low-beam light-emitting unit in which the first anode electrode and the second cathode electrode are electrically connected to the wiring pattern, and a high-beam light-emitting unit in which the first cathode electrode or the second anode electrode is electrically connected to the wiring pattern.

In one embodiment of the present invention, all of the light emitting elements included in the light emitting section are formed of the same type.

In order to solve the above problem, a vehicle lamp according to the present invention includes: the lamp unit of any one of the above; and a control unit that controls power supplied to the light emitting unit via the wiring pattern.

Effects of the invention

In the present invention, it is possible to provide a lamp unit and a vehicle lamp in which the setting of the light beam obtained by a simple configuration can be changed even if the LED chip and the LDM are shared.

Drawings

Fig. 1 is an exploded perspective view showing a lamp unit 100 in the first embodiment.

Fig. 2 is a schematic plan view showing the light source module 40 in the first embodiment.

Fig. 3 is a schematic cross-sectional view showing a structural example of the LED chips included in the light emitting elements 42a to 42d, fig. 3(a) shows a case where current is supplied to two light emitting layers at the same time, and fig. 3(b) shows a case where current is supplied only to one of the two light emitting layers.

Fig. 4 is a schematic plan view partially enlarged and showing the structure of a light emitting section including light emitting elements 42a to 42d in light source module 40 according to the first embodiment.

Fig. 5 is an equivalent circuit diagram of the low beam light emitting unit and the high beam light emitting unit in the light source module 40 shown in fig. 4.

Fig. 6 is an equivalent circuit diagram of the low beam light emitting unit and the high beam light emitting unit in the modification of the first embodiment.

Fig. 7 is a schematic plan view showing a light source module 40 in the second embodiment.

Fig. 8 is a schematic plan view partially enlarged and showing the structure of a light emitting section including light emitting elements 42a to 42d in a light source module 40 according to a second embodiment.

Fig. 9 is an equivalent circuit diagram of the light emitting portion in the light source module 40 shown in fig. 8.

Fig. 10 is an equivalent circuit diagram showing a light emitting section used in a conventional lamp unit, where fig. 10(a) shows a case where four LED chips are connected in series, and fig. 10(b) shows a case where five LED chips are connected in series.

Description of the reference numerals

100 luminaire unit

10 lens

20 lens holder

30 reflector

40 light source module

50 radiator

60 Cooling fan

41 wiring board

42 a-42 d light emitting element

421 growth substrate

422 first n-type layer

423 first luminescent layer

424 first p-type layer

425 p type high concentration layer

426 n type high concentration layer

427 second n-type layer

428 second luminescent layer

429 second p-type layer

Ea anode electrode

Em intermediate electrode

Ec cathode electrode

43 supply power connector

44 fixed part

45 wiring pattern

A1 and A2 anode wiring patterns

Cathode wiring patterns of C1 and C2

46a anode electrode pad

46c cathode electrode pad

46m intermediate electrode pad

47 metal wire

Detailed Description

(first embodiment)

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or equivalent constituent elements, members, and processes shown in the respective drawings are denoted by the same reference numerals, and overlapping descriptions are appropriately omitted. Fig. 1 is an exploded perspective view showing a lamp unit 100 in the present embodiment. The lamp unit 100 includes: the lens 10, the lens holder 20, the reflector 30, the light source module 40, the heat sink 50, and the cooling fan 60 are positioned with each other and fixed by a fixing mechanism not shown.

The lens 10 is made of a translucent material and is a member for irradiating the light from the light source module 40 forward so as to have a predetermined light distribution. The lens holder 20 is a member for holding the lens 10 while maintaining the relative positional relationship between the lens and the light source module 40 and the reflector 30. The reflector 30 is a member that is disposed in front of the light source module 40 and reflects light from the light source module 40 to the front.

The light source module 40 emits light in response to power and signals supplied from the outside of the lamp unit 100. The heat sink 50 is a member having good thermal conductivity and disposed in contact with the light source module 40 on the rear surface of the light source module 40, and has fins formed on the rear surface side. The cooling fan 60 is disposed on the back side of the radiator 50, and generates a flow of air by supplying electric power.

In the lamp unit 100, when power and a signal are supplied from the outside, a current is supplied from the LDM as a control unit to the light source module 40 to emit light, and the light reflected forward by the reflector 30 is irradiated forward through the lens holder 20 and the lens 10. The heat generated by the light source module 40 is dissipated to the air through the heat sink 50, and is cooled by the air blown from the cooling fan 60.

Fig. 2 is a schematic plan view showing the light source module 40 in the present embodiment. As shown in fig. 2, the light source module 40 includes a wiring board 41, light emitting elements 42a to 42d, a power supply connector 43, and a fixing portion 44. In the present embodiment, the

light emitting elements

42a and 42b are connected in series to constitute a high beam light emitting section, and the

light emitting elements

42c and 42d are connected in series to constitute a low beam light emitting section. In the example shown in fig. 2, when only the

light emitting elements

42c and 42d included in the low-beam light emitting portion are turned on, the light distribution for low beam is externally radiated from the lamp unit 100. When all the light emitting elements 42a to 42d of the high beam light emitting unit and the low beam light emitting unit are lit, the light distribution for high beam is radiated from the lamp unit 100 to the outside.

The wiring board 41 is a substantially flat plate-shaped member made of a material having good thermal conductivity, and has a wiring pattern (not shown) formed on one surface thereof, and a light-emitting circuit configured by mounting a plurality of electronic components (not shown), light-emitting elements 42a to 42d, and a power feeding connector 43 thereon. The material constituting the wiring board 41 is not limited, but a metal having good thermal conductivity such as copper or aluminum is preferably used.

As the wiring board 41, a composite board in which an insulating board is bonded to a conductive board may be used, and for example, a board in which a glass epoxy layer is bonded to a metal board may be used. When the wiring board 41 is formed of a metal substrate, an oxidation preventing film is preferably formed on the back surface side of the wiring board 41 in order to prevent a decrease in thermal conductivity due to oxidation of the metal material. As a method for forming the oxidation preventing film, a preflux treatment or an Au plating treatment may be mentioned, but from the viewpoint of improving heat dissipation, an Au plating treatment is preferable.

The light emitting elements 42a to 42d are LED packages each including an LED chip, and include a conventionally known base, a resin seal, a wavelength conversion member including a phosphor, and the like. As described later, the pad electrodes extend from the light emitting elements 42a to 42d, and the pad electrodes and the wiring patterns are bonded to each other by metal wires. The structure of the LED chips included in the light emitting elements 42a to 42d will be described later.

The power supply connector 43 is a member for ensuring electrical connection with the outside mounted on the surface of the wiring board 41, and a plurality of terminals are electrically connected to the wiring pattern. The shape of the power feeding connector 43 is shown as a substantially rectangular parallelepiped shape in fig. 2, but the shape, the shape of the terminal, and the like are not limited as long as they can be connected to a known cable harness.

In the light source module 40, a current controlled by the LDM as a control unit is supplied to the light emitting elements 42a to 42d constituting the light emitting section via the wiring pattern, and light is emitted with a predetermined light beam. The lamp unit 100 is used as a headlamp as a vehicle lamp, and irradiates light to the front of a vehicle.

Fig. 3 is a schematic cross-sectional view showing a structural example of the LED chips included in the light emitting elements 42a to 42d, fig. 3(a) shows a case where current is supplied to two light emitting layers at the same time, and fig. 3(b) shows a case where current is supplied only to one of the two light emitting layers. As shown in fig. 3(a) and (b), the LED chips included in the light-emitting elements 42a to 42d have a structure in which a growth substrate 421, a first n-type layer 422, a first light-emitting layer 423, a first p-type layer 424, a p-type high-concentration layer 425, an n-type high-concentration layer 426, a second n-type layer 427, a second light-emitting layer 428, and a second p-type layer 429 are stacked.

The growth substrate 421 is a single crystal substrate formed of a material capable of growing a semiconductor layer crystal. For growing the nitride semiconductor layer, a substrate of a known material and structure such as a sapphire substrate, a SiC substrate, or a GaN substrate can be used.

The first n-type layer 422 is a semiconductor layer having n-type conductivity grown on the growth substrate 421. A groove is formed in a partial region of the LED chip by etching or the like until the first n-type layer 422 is exposed, and a cathode electrode Ec is formed on the exposed first n-type layer 422. In fig. 3, the first n-type layer 422 is shown as a single layer, but may have a multilayer structure including a known structure such as a buffer layer, an underlayer, an n-type contact layer, or an n-type cladding layer. The material constituting the first n-type layer 422 is not limited, and known materials such as GaN, AlN, and AlGaN may be used. The first n-type layer 422 may be undoped or doped with an n-type impurity, but is preferably doped with an n-type impurity on the surface where the cathode electrode Ec is formed.

First light-emitting layer 423 is a semiconductor layer grown on first n-type layer 422, and is made of a material having a smaller band gap than first n-type layer 422 and first p-type layer 424. The first light-emitting layer 423 has a double hetero structure sandwiched between the first n-type layer 422 and the first p-type layer 424, and emits light of a wavelength corresponding to a band gap by blocking carriers and recombining the light emission. Specific examples of the first light-emitting layer 423 include blue InGaN having an emission wavelength of 430 to 460 nm.

The first p-type layer 424 is a semiconductor layer having p-type conductivity grown over the first light-emitting layer 423. In fig. 3, the first p-type layer 424 is shown as a single layer, but may have a multilayer structure including a known structure such as an anti-overflow layer or a p-type cladding layer. The material constituting first p-type layer 424 is not limited, and a known material such as GaN, AlN, or AlGaN may be used.

The p-type high concentration layer 425 is a semiconductor layer having p-type conductivity grown on the first p-type layer 424, and is doped with p-type impurities at a higher concentration than the first p-type layer 424. For example, the impurity concentration of the p-type high concentration layer 425 is 1.0 × 10²⁰cm^-3Right and left. The thickness of the p-type high concentration layer 425 is preferably about several nm to 10 nm.

The n-type high concentration layer 426 is a semiconductor layer having n-type conductivity grown on the p-type high concentration layer 424, and is doped with n-type impurities at a higher concentration than the first n-type layer 422. For example, the impurity concentration of the n-type high concentration layer 426 is 1.0 × 10²⁰cm^-3Right and left. The thickness of the n-type high concentration layer 426 is preferably about several nm to 10 nm. The p-type high concentration layer 425 and the n-type high concentration layer 426 are in contact with each other at a film thickness of about several nm to 10nm, thereby forming a tunnel junction.

The second n-type layer 427 is a semiconductor layer having n-type conductivity grown on the n-type high concentration layer 426. A groove is formed in a partial region of the LED chip by etching or the like until the second n-type layer 427 is exposed, and an intermediate electrode Em is formed on the exposed second n-type layer 427. In fig. 3, the second n-type layer 427 is shown as a single layer, but may be a multilayer structure including a known structure such as an n-type contact layer or an n-type cladding layer. The material constituting the second n-type layer 427 is not limited, and a known material such as GaN, AlN, or AlGaN may be used. Second n-type layer 427 may be undoped or doped with an n-type impurity, but it is preferable that the surface on which intermediate electrode Em is formed be doped with an n-type impurity.

The second light emitting layer 428 is a semiconductor layer grown on the second n-type layer 427 and is made of a material having a smaller band gap than the second n-type layer 427 and the second p-type layer 429. The second light-emitting layer 428 has a double hetero structure sandwiched between the second n-type layer 427 and the second p-type layer 429, and emits light of a wavelength corresponding to a band gap by blocking carriers and recombining the light emission. Specific examples of the second light-emitting layer 428 include blue InGaN having an emission wavelength of 430 to 460 nm.

The second p-type layer 429 is a semiconductor layer having p-type conductivity grown on the second light-emitting layer 428. Further, an anode electrode Ea is formed on the surface of the second p-type layer 429. In fig. 3, the second p-type layer 429 is shown as a single layer, but may have a multilayer structure including a known structure such as a spill-proof layer, a p-type contact layer, or a p-type cladding layer. The material constituting the second p-type layer 429 is not limited, and known materials such as GaN, AlN, and AlGaN may be used.

The cathode electrode Ec, the intermediate electrode Em, and the anode electrode Ea are electrodes formed on exposed surfaces of the first n-type layer 422, the second n-type layer 427, and the second p-type layer 429, respectively. The specific materials of the cathode electrode Ec, the intermediate electrode Em, and the anode electrode Ea are not limited, but a material having good ohmic contact with each layer is preferably used, and for example, a multilayer structure such as Ni/Pt/Au or Ti/Pt/Au can be used.

As shown in fig. 3(a), when a voltage is applied between the anode electrode Ea and the cathode electrode Ec of the LED chip, a current flows from the second p-type layer 429 to the first n-type layer 422, and light emission is generated in the double layers of the first light-emitting layer 423 and the second light-emitting layer 428 and recombined to irradiate light, respectively. As shown in fig. 3(b), when a voltage is applied between the anode electrode Ea and the intermediate electrode Em of the LED chip, a current flows from the second p-type layer 429 to the second n-type layer 427, and light emission recombination occurs in the second light-emitting layer 428, whereby light is irradiated. Likewise, when a voltage is applied between the intermediate electrode Em and the cathode Ec of the LED chip, a current flows from the second n-type layer 427 to the first n-type layer 422, light emission recombination is generated in the first light-emitting layer, and light is irradiated.

At this time, a tunnel junction composed of p-type high concentration layer 425 and n-type high concentration layer 426 is interposed between second n-type layer 427 and first p-type layer 424, and thus current is injected from second n-type layer 427 to first p-type layer 424 via the tunnel junction. When the first light-emitting layer 423 and the second light-emitting layer 428 emit blue light, part of the blue light is converted into yellow light by the wavelength conversion member included in the light-emitting elements 42a to 42d, and the white light is extracted to the outside by mixing the blue light and the yellow light.

Fig. 4 is a schematic plan view partially enlarged to show the structure of the light emitting section including the light emitting elements 42a to 42d in the light source module 40 of the present embodiment. As shown in fig. 4, a wiring pattern 45 for electrically connecting the light emitting elements 42a to 42d is formed on the wiring substrate 41. Each of the light-emitting elements 42a to 42d is provided with an anode electrode pad 46a, an intermediate electrode pad 46m, and a cathode electrode pad 46c electrically connected to the anode electrode Ea, the intermediate electrode Em, and the cathode electrode Ec of the LED chip.

The anode electrode pad 46a, the intermediate electrode pad 46m, and the cathode electrode pad 46c of the wiring pattern 45 are wire-bonded via a metal wire 47, and are electrically connected to the light-emitting elements 42a to 42 d. In the example shown in fig. 4, the anode electrode pads 46a and the cathode electrode pads 46c of the

light emitting elements

42a, 42b, and 42d are connected to the wiring pattern 45 via metal wires 47. The intermediate electrode pad 46m and the cathode electrode pad 46c of the light-emitting element 42c are connected to the wiring pattern 45 via a metal wire 47.

The cathode electrode pad 46c of the light-emitting element 42a and the anode electrode pad 46a of the light-emitting element 42b are electrically connected via the wiring pattern 45. Similarly, the cathode electrode pad 46c of the light emitting element 42c and the anode electrode pad 46a of the light emitting element 42d are electrically connected via the wiring pattern 45. Therefore, the

light emitting elements

42a and 42b are connected in series via the wiring pattern 45 and the metal wires 47 to constitute a low beam light emitting section, and the

light emitting elements

42c and 42d are connected in series to constitute a high beam light emitting section.

Here, the wiring pattern 45 and the metal wire 47 that electrically connect the cathode electrode pads 46c of the

light emitting elements

42a, 42c and the anode electrode pads 46a of the

light emitting elements

42b, 42d connect the

light emitting elements

42a, 42b of the near-beam light emitting section and the

light emitting elements

42c, 42d of the far-beam light emitting section in series, and correspond to the inter-light emitting element wiring in the present invention. On the other hand, the wiring pattern 45 and the metal line 47 connected to the anode electrode pad 46a of the light-emitting element 42a, the cathode electrode pad 46c of the light-emitting element 42b, the intermediate electrode pad 46m of the light-emitting element 42c, and the cathode electrode pad 46c of the light-emitting element 42d are wirings other than the wiring between the light-emitting elements.

In the example shown in fig. 4, the light-emitting element 42a is connected to the anode side of the high-beam light-emitting part, and corresponds to the first light-emitting element in the present invention. The light emitting element 42b is connected to the cathode side of the high beam light emitting unit, and corresponds to the second light emitting element in the present invention. Similarly, the light emitting element 42c is connected to the anode side of the low beam light emitting part, and corresponds to the first light emitting element in the present invention. The light emitting element 42d is connected to the cathode side of the low beam light emitting portion, and corresponds to the second light emitting element in the present invention.

Fig. 5 is an equivalent circuit diagram of the low beam light emitting unit and the high beam light emitting unit in the light source module 40 shown in fig. 4. As shown in fig. 5, the light-emitting elements 42a to 42d are each formed by connecting tunnel diodes in series between the first light-emitting layer 423 and the second light-emitting layer 428. The anode electrode pad 46a, the intermediate electrode pad 46m, and the cathode electrode pad 46c of the light-emitting elements 42a to 42d are connected to the wiring pattern 45 not constituting the wiring between the light-emitting elements by a metal wire 47 alternatively.

In the example shown in fig. 4 and 5, the anode electrode pads 46a are selected in the light emitting element 42a so as to be connected to the anode wiring pattern a1 of the wiring pattern 45. In the light emitting element 42b, the cathode electrode pads 46C are selected alternatively and connected to the cathode wiring pattern C1 of the wiring pattern 45. In the light-emitting element 42c, the intermediate electrode pads 46m are selected alternatively and connected to the anode wiring pattern a2 of the wiring pattern 45. In the light emitting element 42d, the cathode electrode pads 46C are selected alternatively and connected to the cathode wiring pattern C2 of the wiring pattern 45.

Therefore, in the low beam light emitting portion, current flows from the anode wiring pattern a1 to the cathode wiring pattern C1, and the first light emitting layer 423 and the second light emitting layer 428 of each of the

light emitting elements

42a and 42b emit light, and light beams from the four light emitting layers in total are obtained. In the high beam light-emitting unit, current flows from the anode wiring pattern a2 to the cathode wiring pattern C2, and the first light-emitting layer 423 of the light-emitting element 42C, the first light-emitting layer 423 of the light-emitting element 42d, and the second light-emitting layer 428 emit light, and light beams from the total three light-emitting layers are obtained.

Since all the light-emitting elements 42a to 42d included in the high beam light-emitting unit and the low beam light-emitting unit are formed of the same kind and the amounts of light emitted from the first light-emitting layer 423 and the second light-emitting layer 428 are also the same, the luminous fluxes of the light emitted from the high beam light-emitting unit and the low beam light-emitting unit are proportional to the number of light-emitting layers included in the anode wiring pattern a1 to the cathode wiring pattern C1.

As an example, when the luminous flux obtained by light emission in one of the first light-emitting layer 423 and the second light-emitting layer 428 is 250 lumens, in the examples shown in fig. 4 and 5, 1000 lumens are obtained from the low beam light-emitting portion and 750 lumens are obtained from the high beam light-emitting portion. This is because the luminous flux obtained when the high beam luminous element and the low beam luminous element are simultaneously lit is 1750 lumens, the luminous flux ratio in the low beam luminous element is 57%, and the luminous flux ratio in the high beam luminous element is 43%. This is preferable because the light flux from the low-beam light emitting unit is 1000 lumens or more and 55 to 70% of the light flux.

As described above, in the lamp unit 100 and the vehicle lamp according to the present embodiment, among the light emitting elements 42a to 42d closest to the anode side and the cathode side, any one of the anode electrode pads 46a, the intermediate electrode pads 46m, and the cathode electrode pads 46c is electrically connected to the wiring pattern 45 in an alternative manner, and the number of light emitting layers contributing to light emission is set. Thus, the LED chip and the LDM are shared, and the setting of the light beam obtained by a simple configuration can be changed.

As shown in fig. 1, in the lamp unit 100 and the vehicle lamp, light from the high beam light emitting portion and the low beam light emitting portion is irradiated to the outside through the lens 10. Since the distribution of light emitted from the lens 10 to the outside is determined by the relative positional relationship between the lens 10 and the light-emitting region, if the light-emitting regions of the high-beam light-emitting portion and the low-beam light-emitting portion change, the distribution changes. However, in this embodiment, even when a structure in which the first light-emitting layer 423 and the second light-emitting layer 428 are stacked on the same substrate is used as an LED chip, the area and position of the light-emitting region in a plan view do not change. Therefore, in the present embodiment, even if any one of the anode electrode pad 46a, the intermediate electrode pad 46m, and the cathode electrode pad 46c is connected to the wiring pattern 45 in an alternative manner and the obtained light beam is selected, it is possible to suppress a change in the light distribution irradiated from the lens 10 to the outside.

Further, since the light emitting elements 42a to 42d included in the high beam light emitting portion and the low beam light emitting portion are all formed of the same type of LED chip, the number of components can be reduced, and troubles such as erroneous mounting can be suppressed. Further, since the electrical connection with the anode electrode pad 46a, the intermediate electrode pad 46m, and the cathode electrode pad 46c is made by the wiring pattern 45 and the metal wire 47, the connection state can be easily confirmed by visual observation.

(modification of the first embodiment)

Fig. 6 is an equivalent circuit diagram of the low beam light emitting unit and the high beam light emitting unit in the present modification. In the first embodiment, an example in which two LED chips are connected in series is shown as the low-beam light emitting unit and the high-beam light emitting unit, but in the present modification, an example in which the low-beam light emitting unit and the high-beam light emitting unit are configured by one LED chip is shown.

In the example shown in fig. 6, the light-emitting element 42a constitutes a low-beam light-emitting section, the anode electrode pad 46a is connected to the anode wiring pattern a1, and the cathode electrode pad 46C is connected to the cathode wiring pattern C1. The light-emitting element 42C constitutes a high beam light-emitting section, the anode electrode pad 46a is connected to the anode wiring pattern a2, and the cathode electrode pad 46C is connected to the cathode wiring pattern C2.

Therefore, in the low beam light emitting portion, current flows from the anode wiring pattern a1 to the cathode wiring pattern C1, and the first light emitting layer 423 and the second light emitting layer 428 of the light emitting element 42a emit light, and light beams from the two light emitting layers in total are obtained. In the high beam light-emitting unit, current flows from the anode wiring pattern a2 to the cathode wiring pattern C2, and the first light-emitting layer 423 of the light-emitting element 42C emits light, and a light beam from a total of one light-emitting layer is obtained.

As an example, when the luminous flux obtained by light emission in one of the first light-emitting layer 423 and the second light-emitting layer 428 is 500 lumens, in the example shown in fig. 6, 1000 lumens are obtained from the low beam light-emitting portion and 500 lumens are obtained from the high beam light-emitting portion. This is because the luminous flux obtained when the high-beam light emitting unit and the low-beam light emitting unit are simultaneously lit is 1500 lumens, the luminous flux ratio in the low-beam light emitting unit is 67%, and the luminous flux ratio in the high-beam light emitting unit is 33%. This is preferable because the light flux from the low-beam light emitting unit is 1000 lumens or more and 55 to 70% of the light flux.

Table 2 shows the number of LED chips, the light flux passing through one light-emitting layer, and the beam ratio in the light-emitting portion for high beam and the light-emitting portion for low beam in the first embodiment and the present modification.

[ Table 2]

In the present modification, in the light-emitting

elements

42a and 42c, any one of the anode electrode pad 46a, the intermediate electrode pad 46m, and the cathode electrode pad 46c is selected to be electrically connected to the wiring pattern 45, and the number of light-emitting layers contributing to light emission is set. Thus, even if the LED chip and the LDM are shared, the setting of the light beam obtained by the simple configuration can be changed.

(second embodiment)

Next, a second embodiment of the present invention will be described with reference to fig. 7 to 9. The description of the same contents as those of the first embodiment will be omitted. Fig. 7 is a schematic plan view showing the light source module 40 in the present embodiment. As shown in fig. 7, the light source module 40 includes a wiring board 41, light emitting elements 42a to 42d, a power supply connector 43, and a fixing portion 44. In the present embodiment, the light emitting elements 42a to 42d are connected in series to constitute a light emitting section. In the example shown in fig. 7, the lamp unit 100 includes a conventionally known shutter member, and switches between the light distribution for high beam and the light distribution for low beam.

Fig. 8 is a schematic plan view partially enlarged to show the structure of the light emitting section including the light emitting elements 42a to 42d in the light source module 40 of the present embodiment. As shown in fig. 8, a wiring pattern 45 for electrically connecting the light emitting elements 42a to 42d is formed on the wiring substrate 41. Further, the light-emitting

elements

42a and 42d are provided with an anode electrode pad 46a, an intermediate electrode pad 46m, and a cathode electrode pad 46c electrically connected to the anode electrode Ea, the intermediate electrode Em, and the cathode electrode Ec of the LED chip.

In the example shown in fig. 8, the anode electrode pad 46a of the light emitting element 42a and the cathode electrode pad 46c of the light emitting element 42d are connected to the wiring pattern 45 via the metal wire 47. The light emitting elements 42a to 42d are connected in series and housed in one package, and are collectively sealed with a wavelength conversion member containing a phosphor. Here, the wiring in the package connecting the light emitting elements 42a to 42d in series corresponds to the inter-light emitting element wiring in the present invention. On the other hand, the wiring pattern 45 and the metal line 47 connected to the anode electrode pad 46a of the light emitting element 42a and the cathode electrode pad 46c of the light emitting element 42d are wirings other than the wirings between the light emitting elements.

In the example shown in fig. 8, the light-emitting element 42a is connected to the anode side of the light-emitting portion and corresponds to the first light-emitting element in the present invention, and the light-emitting element 42d is connected to the cathode side of the light-emitting portion and corresponds to the second light-emitting element in the present invention. The

light emitting elements

42b and 42c are connected in series between the light emitting element 42a and the light emitting element 42d, and correspond to other light emitting elements in the present invention. The

light emitting elements

42b and 42c are connected in series by connecting the anode electrode Ea and the cathode electrode Ec in the package of the light emitting section, and the intermediate electrode Em is insulated from the wiring pattern 45 on the wiring substrate 41.

Fig. 9 is an equivalent circuit diagram of the light emitting portion in the light source module 40 shown in fig. 8. The anode electrode pad 46a, the intermediate electrode pad 46m, and the cathode electrode pad 46c of the

light emitting elements

42a and 42d are connected to the wiring pattern 45 not constituting the wiring between the light emitting elements by a metal wire 47 alternatively.

In the example shown in fig. 8, the anode electrode pad 46a of the light-emitting element 42a is selected to be connected to the anode wiring pattern a1 of the wiring pattern 45, and the cathode electrode pad 46C of the light-emitting element 42d is selected to be connected to the cathode wiring pattern C1 of the wiring pattern 45. Therefore, in the example shown in fig. 8, current flows from the anode wiring trace a1 to the cathode wiring trace C1, and the first light-emitting layer 423 and the second light-emitting layer 428 of each of the light-emitting elements 42a to 42b emit light, thereby obtaining light fluxes from a total of eight light-emitting layers.

Since all the light-emitting elements 42a to 42d included in the light-emitting portion are formed of the same kind and the amounts of light emitted from the first light-emitting layer 423 and the second light-emitting layer 428 are also the same, the luminous flux of light emitted in the light-emitting portion is proportional to the number of light-emitting layers included from the anode wiring pattern a1 to the cathode wiring pattern C1. As an example, when 333 lumens is used as the luminous flux obtained by light emission in one of the first light-emitting layer 423 and the second light-emitting layer 428, a luminous flux of 2664 lumens is obtained in the entire light-emitting portion in the example shown in fig. 8. In this way, by connecting the wiring pattern 45 alternatively so as to maximize the number of light-emitting layers contributing to light emission, it is possible to satisfy the reference or insurance application reference required for the vehicle lamp in the area where the amount of light (light beam) is large.

On the other hand, a case where the intermediate electrode pads 46m of the light-emitting

elements

42a and 42d are selected and connected to the anode wiring pattern a2 and the cathode wiring pattern C2 by metal wires, respectively, is considered. In this case, current flows from the anode wiring pattern a2 to the cathode wiring pattern C2, and the first light-emitting layer 423 of the light-emitting element 42C, the first light-emitting layer 423 and the second light-emitting layer 428 of the light-emitting elements 42b and 42C, and the second light-emitting layer 428 of the light-emitting element 42d emit light, and a light flux of 1998 lumens is obtained from the total of six light-emitting layers.

Similarly, in the light-emitting

elements

42a and 42d, the number of light-emitting layers contributing to light emission can be set by selecting one of the anode electrode pad 46a, the intermediate electrode pad 46m, and the cathode electrode pad 46c to be electrically connected to the wiring pattern 45. In an area where the light quantity required for the vehicle lamp is not large, the wiring pattern 45 is connected by a combination including the number of necessary light emitting layers, so that the necessary light quantity can be obtained with appropriate power consumption.

As described above, in the lamp unit 100 and the vehicle lamp according to the present embodiment, in the

light emitting elements

42a and 42d closest to the anode side and the cathode side, any one of the anode electrode pad 46a, the intermediate electrode pad 46m, and the cathode electrode pad 46c is electrically connected to the wiring pattern 45 in an alternative manner, and the number of light emitting layers contributing to light emission is set. Further, since the light amount can be set by the number of light emitting layers contributing to light emission, the LED chip and the LDM can be driven at a constant current value regardless of the light amount, and the setting of the light beam obtained by a simple configuration can be changed by sharing the LED chip and the LDM.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included in the technical scope of the present invention.

Claims

1. A lamp unit is characterized by comprising:

a light emitting unit in which a plurality of light emitting elements are connected in series by an inter-light emitting element wiring;

a wiring board on which a wiring pattern for supplying power to the light emitting section is formed;

the light-emitting element is formed by overlapping a first light-emitting layer and a second light-emitting layer in a lamination direction, and includes: a cathode electrode connected to a cathode side of the first light-emitting layer; an intermediate electrode connected between the first light-emitting layer and the second light-emitting layer; an anode electrode connected to the anode side of the second light-emitting layer;

in a first light emitting element connected to an anode side most among the plurality of light emitting elements, any one of a first anode electrode, a first intermediate electrode, and a first cathode electrode is electrically connected to the wiring pattern other than the inter-light emitting element wiring,

in a second light emitting element connected to the cathode side most among the plurality of light emitting elements, any one of a second cathode electrode, a second intermediate electrode, and a second anode electrode is electrically connected to the wiring pattern other than the inter-light emitting element wiring.

2. The luminaire unit of claim 1,

one or more other light-emitting elements are connected in series between the first light-emitting element and the second light-emitting element,

in the other light emitting element, the intermediate electrode and the wiring pattern are insulated from each other.

3. Lamp unit according to claim 1 or 2,

the plurality of light emitting units include a low beam light emitting unit and a high beam light emitting unit,

in the low-beam light emitting portion, the first anode electrode and the second cathode electrode are electrically connected to the wiring pattern,

in the high-beam light emitting unit, the first cathode electrode or the second anode electrode is electrically connected to the wiring pattern.

4. Lamp unit according to any one of claims 1 to 3,

the light-emitting elements included in the light-emitting portion are all composed of the same kind.

5. A vehicle lamp is characterized by comprising:

the luminaire unit of any one of claims 1-4;

and a control unit that controls power supplied to the light emitting unit via the wiring pattern.