Lighting device

Abstract

Provided is an illumination device suitable for a rear combination lamp of an automobile, which has a high degree of design freedom and achieves low cost. The illumination device (10) includes: light-emitting elements (41, 42, 43) having a light-emitting peak wavelength in the wavelength range of 400 to 510 nm; a first phosphor (51) having a light-emitting peak wavelength in the wavelength range of 485 to 700 nm; a second phosphor (52) having a light-emitting peak wavelength in the wavelength range of 510 to 590 nm; a third phosphor (53) having a light-emitting peak wavelength in the wavelength range of 600 to 700 nm; and a filter (2) having a light transmittance of 80% or more for light with a wavelength of 600 to 730 nm and a light transmittance of 3% or more and 50% or less for light with a wavelength of 410 to 480 nm. The filter (2) transmits a part of the light (L G ) emitted from the first phosphor (51), at least a part of the light (L Y ) emitted from the second phosphor (52), and at least a part of the light (L Ri ) emitted from the third phosphor (53), and emits the light (L W , L A , L R ) after passing through the filter (2) to the outside.

Description

[0001] Cross - reference to related applications

[0002] This application is a divisional application of the application with application number 201910086770.5 and invention title "lighting device", which was filed on January 29, 2019. Technical field

[0003] The present invention relates to a lighting device. Background art

[0004] In an automobile, it is stipulated that a brake lamp (Stop lamp, brake lamp), a turn signal lamp (turn signal lamp, turn signal), a tail lamp, a back lamp, and a rear reflector must be provided on the rear surface of the vehicle body, and further, standards for the color, brightness, etc. of the light and the reflected light are respectively stipulated. These lamps are integrated into one unit and are installed on the vehicle body in the form of a pair of rear combination lamps on the left and right. A common rear combination lamp uses the following lighting device, that is, according to the divided areas, it emits at least one of red light (serving as both a brake lamp and a tail lamp), orange light (for the turn signal), and white light (for the back lamp), that is, two - color or three - color light. In addition, the rear combination lamp is sometimes designed into a unique design through the color combination and shape formed by the light color as an ornament of the automobile.

[0005] Such a lighting device for an automobile includes a light - emitting device such as a light - emitting diode (LED) as a light source and is housed in a substrate (housing) with a reflective film provided on its inner surface. In the lighting device, an opening of the substrate is covered with a plate - shaped cover (outer lens) made of a transparent resin or the like, which serves as a light - irradiation surface. The lighting device has: a red cover. In order to have a rear reflector with red - reflected light, the cover in the area of the red lamp includes a transparent resin or the like colored red with a pigment; and a transparent (clear) cover, which is used in combination with a light - emitting device that emits white light to serve as the area of the white lamp, or the lighting device also has an orange cover in an area such as orange. Therefore, the cover of the lighting device uses a two - color plate of transparent and red, or a three - color plate with orange added therein, and is installed on the substrate separately or used in a sheet obtained by integrally molding a resin material and then color - separating it.

[0006] However, when the cover covering the surface is composed of two or more types of plates, according to the design, the shape of the components constituting the cover may become complicated or the number of components may increase. In addition, in order to form such a cover in an integrally molded manner, the mold becomes a complicated shape and it is even difficult to form. Therefore, a lighting device is being developed which can irradiate orange light and white light by covering the entire irradiation surface with only a red cover, rather than just irradiating red light (Patent Documents 1 and 2).

[0007] Prior Art Documents

[0008] Patent Documents

[0009] Patent Document 1: Japanese Patent Laid-Open No. 2009-117115

[0010] Patent Document 2: Japanese Patent Laid-Open No. 2004-241348 Summary of the Invention

[0011] Technical Problem to be Solved by the Invention

[0012] In the lighting device described in Patent Document 1, it is necessary to restrictively laminate a complementary color inner film in the region where the cover emits white light, which may lead to a reduction in productivity. The lighting device described in Patent Document 2 is difficult to achieve a specified light color.

[0013] The subject of the embodiment of the present invention is to provide a lighting device for a rear combination lamp for an automobile which can easily obtain a specified light color, has a high degree of design freedom, and realizes low cost.

[0014] Technical Means for Solving the Problem

[0015] The lighting device according to an embodiment of the present invention includes: a first light-emitting element having a light-emitting peak wavelength in the range of 400 nm or more and 510 nm or less; a first phosphor disposed at a position where the light emitted from the first light-emitting element is incident and excited by the light to have a light-emitting peak wavelength in the range of 485 nm or more and 700 nm or less; and a filter having a light transmittance of 80% or more for light having a wavelength in the range of 600 nm or more and 730 nm or less, and a light transmittance of 3% or more and 50% or less for light having a wavelength in the range of 410 nm or more and 480 nm or less. The filter is disposed at a position where the first light emitted from the first phosphor is incident, transmits a part of the first light, and the lighting device of the present invention is configured to emit the light transmitted through the filter.

[0016] Advantages of the Invention

[0017] According to the embodiments of the present invention, even if a cover including a red filter is provided on the entire irradiation surface, a specified light color other than red can be obtained, which not only has a high degree of design freedom but also can reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 FIG. is an external view schematically showing a state where the lighting device according to the embodiment is installed on a vehicle body.

[0019] Figure 2 FIG. is a cross-sectional view schematically showing a partially enlarged structure of the lighting device according to the embodiment.

[0020] Figure 3 FIG. is a chromaticity diagram for explaining the transition of the chromaticity of light based on the filter in the lighting device according to the embodiment.

[0021] Figure 4 FIG. is a cross-sectional view schematically showing a partially enlarged structure of the lighting device according to a modified example of the embodiment.

[0022] Figure 5 FIG. is a chart showing the emission spectra of white light and the light before passing through the filter, and the transmission spectrum of the filter in the lighting device according to the example.

[0023] Figure 6 FIG. is a chart showing the emission spectra of orange light and the light before passing through the filter, and the transmission spectrum of the filter in the lighting device according to the example.

[0024] Figure 7 FIG. is a chart showing the emission spectra of red light and the light before passing through the filter, and the transmission spectrum of the filter in the lighting device according to the example.

[0025] Figure 8 FIG. is a chromaticity diagram showing the chromaticity coordinates before and after passing through the filter of the lighting device according to the example.

[0026] REFERENCE SIGNS

[0027] 10, 10A Lighting device

[0028] 11, 11A First light-emitting device

[0029] 12, 12A Second light-emitting device

[0030] 13, 13A Third light-emitting device

[0031] 2 Filter

[0032] 3 Housing

[0033] 41 First light-emitting element

[0034] 42nd second light-emitting element

[0035] 43rd third light-emitting element

[0036] 51, 51A first phosphor layer

[0037] 52, 52A second phosphor layer

[0038] 53, 53A third phosphor layer

[0039] 6 package

[0040] 6A wiring board

[0041] L G First light

[0042] L Y Second light

[0043] L Ri Third light

[0044] L W White light

[0045] L A Orange light

[0046] L R Red light Detailed implementation manners

[0047] Hereinafter, the lighting device according to the embodiment of the present invention will be described. The lighting device according to this embodiment is applicable to a rear combination lamp installed near both ends in the vehicle width direction on the rear surface of a vehicle body, and irradiates light to the rear of the vehicle. It should be noted that, in order to schematically show the embodiment of the present invention, the components shown in the following drawings referred to in the following description may have their sizes, positional relationships, etc. exaggerated, and in addition, their shapes may be simplified. In addition, in the following description, the same names and symbols generally represent the same or substantially the same components, and detailed descriptions are appropriately omitted.

[0048] 〔Lighting device〕

[0049] Refer to Figure 1 and Figure 2 to describe the structure of the lighting device according to the embodiment of the present invention. Figure 1 is an external view schematically showing the state where the lighting device according to the embodiment is installed on the vehicle body. Figure 2 is a cross-sectional view schematically showing a partially enlarged structure of the lighting device according to the embodiment. It should be noted that in this specification, unless otherwise specified, it is in the same direction as shown Figure 2The same upper and lower parts in the drawings of the sectional view are explained.

[0050] The lighting device 10 comprises: a first light emitting element 41 having a light emission peak wavelength in a range of 400 nm to 510 nm; a first phosphor disposed in the region of the light L emitted by the first light emitting element 41; B1 The position of the incident light L B1 The first fluorescent body is excited to have a peak wavelength of light emission at a wavelength of 485 nm to 700 nm; and a filter 2, the transmittance of light at a wavelength of 600 nm to 730 nm is 80% or more, and the transmittance of light at a wavelength of 410 nm to 480 nm is 3% or more and 50% or less, and the filter is provided in the first light L emitted from the first fluorescent body G The first light L G Furthermore, the lighting device 10 transmits the light L after passing through the filter 2. W Emitted. In addition, the lighting device 10 has a first phosphor layer 51 described later, and the first phosphor layer 51 contains a granular first phosphor. The lighting device 10 also includes: a second light-emitting element 42 and a third light-emitting element 43, each having a light emission peak wavelength of more than 400nm and less than 510nm; a second phosphor layer 52 containing a granular second phosphor; and a third phosphor layer 53 containing a granular third phosphor. Such a lighting device 10 has a first light-emitting device 11 having a first light-emitting element 41 and a first phosphor layer 51 in a recess of a package 6, a second light-emitting device 12 having a second light-emitting element 42 and a second phosphor layer 52 in a recess of a package 6, and a third light-emitting device 13 having a third light-emitting element 43 and a third phosphor layer 53 in a recess of a package 6, and these light-emitting devices are housed in an open box, i.e., a shell 3, and has a filter 2 that blocks the opening of the shell 3. Figure 2 In the figure, for the sake of simplicity, the lighting device 10 is shown as an example in which it includes one first light emitting device 11, one second light emitting device 12, and one third light emitting device 13.

[0051] The lighting device 10 is used as a set of two symmetrical lighting devices at the rear of the vehicle body. The lighting device 10 is in the shape of a rectangular parallelepiped that is long in the vehicle width direction (Y direction) of the vehicle to which it is installed, and is embedded in the vehicle body so that the irradiation surface is exposed at the rear surface of the vehicle body. In addition, the irradiation surface of the lighting device 10 is divided into three areas in the Y direction, and each area sequentially irradiates white light L from the center in the vehicle width direction toward the side of the vehicle body. W , red light L R , Orange light L AIn addition, the lighting device 10 uses external light to reflect red light from the filter 2 that covers the entire irradiation surface. It should be noted that in this specification, orange includes amber.

[0052] White light L W is the light of the reverse lamp of an automobile, and orange light L A is the light of the direction indicator, and red light L R is the light of the brake lamp and the tail lamp, and the light color is specified in JIS D5500. White light L W In the chromaticity coordinates of JIS Z8701, it is specified in the chromaticity range of 0.500 ≥ x ≥ 0.310, y ≤ 0.150 + 0.640x, y ≥ 0.050 + 0.750x, and 0.440 ≥ y ≥ 0.382. Orange light L A In the chromaticity coordinates of JIS Z8701, it is specified in the chromaticity range of 0.429 ≥ y ≥ 0.398 and z ≤ 0.007. Red light L R In the chromaticity coordinates of JIS Z8701, it is specified in the chromaticity range of y ≤ 0.335 and z ≤ 0.008. In addition, the light color of the light reflected from the irradiation surface of the lighting device 10 is preferably specified in the same chromaticity range as that of red light L R To set the light color of such light and reflected light, the components of the lighting device 10 are set to the following structure.

[0053] (The first light-emitting element, the second light-emitting element, the third light-emitting element)

[0054] The first light-emitting element 41, the second light-emitting element 42, and the third light-emitting element 43 are semiconductor light-emitting elements that emit light L B1 、L B2 、L B3 The light L B1 、L B2 、L B3 has a peak wavelength in the range of 400 nm or more and 510 nm or less. As long as the first light-emitting element 41, the second light-emitting element 42, and the third light-emitting element 43 are within the above range, they can have different emission peak wavelengths and can be applied to the same type of semiconductor light-emitting element or different types of semiconductor light-emitting elements. In particular, the emission peak wavelength of the first light-emitting element 41 is preferably 480 nm or less, and preferably 420 nm or more.

[0055] As such a light-emitting element, examples include: In X Al Y Ga 1-X-YAn InGaN-based nitride semiconductor such as N(0≤X≤1, 0≤Y≤1, X+Y<1). In the present embodiment, the first light-emitting element 41, the second light-emitting element 42, and the third light-emitting element 43 have the same structure, and are referred to as the light-emitting element 4 when not specifically specified. The blue light L B1 , L B2 , L B3 is referred to as the blue light L B . The light-emitting element 4 is mounted on the package 6 and is connected to a lead electrode provided so as to be exposed on the bottom surface of the recess of the package 6. The light-emitting element 4 only needs to emit each necessary amount of light at the above wavelength, and there is no particular limitation on the shape, size, mounting method (flip chip, wire bonding), etc.

[0056] (First phosphor layer)

[0057] The first phosphor layer 51 is provided at a position where the light L B1 emitted by the first light-emitting element 41 is incident, and is excited by at least a part of the light of the blue light L B1 to emit light having a specific wavelength whose wavelength is converted to be longer than that of the light. The first phosphor layer 51 is provided to make the blue light L B1 become white light L W after passing through the light filter 2. Therefore, the emission peak wavelength of the first phosphor layer 51 is 485 nm or more and 700 nm or less, preferably 500 nm or more, and preferably 580 nm or less. Examples of such phosphors include: silicate-based oxide phosphors such as chlorosilicate phosphors such as Ca8MgSi4O 16 Cl2:Eu, aluminate phosphors such as Sr4Al 14 O 25 :Eu, oxynitride phosphors such as (Si,Al)6(O,N)8:Eu, BaSi2O2N2:Eu, Ca x (Si,Al) 12 (O,N) 16 :Eu, oxide phosphors such as yttrium aluminum garnet phosphors (YAG phosphors), lutetium aluminum garnet phosphors, terbium aluminum garnet phosphors, and garnet phosphors obtained by replacing a part of their compositions, CaAlSiN3:Eu (CASN phosphor), (Ca,Sr)AlSiN3:Eu, (Ca,Sr)2Si5N8:Eu, (Ba,Sr)2Si5N8:Eu, SrLiAl3N4:Eu, etc. nitride phosphors.

[0058] In the first light-emitting device 11, the first phosphor layer 51, as a sealing member for the first light-emitting element 41, has a transparent resin such as an epoxy resin or a silicone resin in which the first phosphor is dispersed, and is provided by being filled in the recess of the package 6. Moreover, the first phosphor layer 51 wavelength-converts at least a part of the light L emitted by the first light-emitting element 41. As will be described in detail later, for the first phosphor layer 51, one having a desired emission wavelength is selected, and the wavelength conversion rate of the light L emitted by the first light-emitting element 41 is set. The wavelength conversion rate can be adjusted according to the phosphor content in the transparent resin of the first phosphor layer 51, the thickness on the first light-emitting element 41, and the like. B1 And at least a part of it is wavelength-converted. As will be described in detail later, for the first phosphor layer 51, one having a desired emission wavelength is selected, and the wavelength conversion rate of the light L emitted by the first light-emitting element 41 is set. B1 The wavelength conversion rate can be adjusted according to the phosphor content in the transparent resin of the first phosphor layer 51, the thickness on the first light-emitting element 41, and the like.

[0059] (Second phosphor layer)

[0060] The second phosphor layer 52 is provided at a position where the light L emitted by the second light-emitting element 42 is incident, and emits light having a specific wavelength whose wavelength is converted to be longer than that of the light by being excited by at least a part of the blue light L. B2 The second phosphor layer 52 is provided to make the blue light L B2 become orange light L after passing through the color filter 2. B2 A . Therefore, the emission peak wavelength of the second phosphor layer 52 is 510 nm or more and 590 nm or less, preferably 530 nm or more, more preferably 550 nm or more, and preferably 580 nm or less. Examples of such phosphors include oxide phosphors such as yttrium aluminum garnet phosphor (YAG phosphor), lutetium aluminum garnet phosphor, terbium aluminum garnet phosphor, and garnet phosphors obtained by substituting a part of their compositions, chlorosilicate oxide phosphors such as Ca8MgSi4O 16 Cl2:Eu, and oxynitride phosphors such as (Si, Al)6(O, N)8:Eu. In the second light-emitting device 12, the second phosphor layer 52, like the first phosphor layer 51, has a transparent resin in which the second phosphor is dispersed as a sealing member for the second light-emitting element 42, and is provided by being filled in the recess of the package 6. Moreover, the second phosphor layer 52 wavelength-converts at least a part of the light L emitted by the second light-emitting element 42, and preferably wavelength-converts most of it. B2 B2 B2

[0061] (Third phosphor layer)

[0062] The third phosphor layer 53 is provided at a position where the light L emitted by the third light-emitting element 43 is incident, and is excited by the blue light L B3 B3 ​At least a part of the light is excited to emit light having a specific wavelength whose wavelength is converted to a wavelength longer than that of the light. The third phosphor layer 53 is provided to convert blue light L B3 into red light L after passing through the light filter 2 R . Therefore, the emission peak wavelength of the third phosphor layer 53 is 600 nm or more and 700 nm or less, preferably 610 nm or more, and more preferably 630 nm or more. Examples of such phosphors include nitride phosphors such as CaAlSiN3:Eu (CASN phosphor), (Ca, Sr)AlSiN3:Eu, (Ca, Sr)2Si5N8:Eu, SrLiAl3N4:Eu, (Ba, Sr)2Si5N8:Eu, and Ca x (Si, Al) 12 (O, N) 16 :Eu such oxynitride phosphors. In the third light-emitting device 13, the third phosphor layer 53, like the first phosphor layer 51, has a transparent resin in which the third phosphor is dispersed as a sealing member for the third light-emitting element 43, and is provided by being filled in the recess of the package 6. Further, the third phosphor layer 53 wavelength-converts at least a part of the light L emitted by the third light-emitting element 43, and preferably wavelength-converts most of the light. B3

[0063] (Light filter)

[0064] The light filter 2 is provided at a position where the first light L emitted from the first phosphor layer 51 G , the second light L emitted from the second phosphor layer 52 Y and the third light L emitted from the third phosphor layer 53 Ri are incident. The light filter 2 is a cover in the lighting device 10, that is, a so-called outer lens of an automotive lamp, and is provided to impart the function of a reflector of an automobile to at least a part of the irradiation surface of the lighting device 10. As the reflector, the light filter 2 relatively absorbs light other than red light in order to allow light to enter from the outside and reflect red light within the chromaticity range, and transmits the remaining light.

[0065] Furthermore, in order to cause the lighting device 10 to emit white light L W ​, the filter 2 restricts the transmission of light other than red light. Specifically, the transmittance of the filter 2 for light with a wavelength of 600 nm or more and 730 nm or less is 80% or more. Moreover, the transmittance of the filter 2 for light with a wavelength of 410 nm or more and 480 nm or less is 3% or more and 50% or less, preferably 5% or more. Additionally, it is further preferred that the maximum transmittance of the filter 2 for light with a wavelength of 410 nm or more and 480 nm or less is 20% or more. If the transmittance of light in this wavelength region is high, the extraction efficiency of the white light L W becomes high. In addition, the transmittance of the filter 2 for light with a wavelength of 500 nm or more and 550 nm or less is preferably 20% or less. Due to the above characteristics of the filter 2, the lighting device 10 uses the light transmitted through one filter 2 as the three-color light L W 、L A 、L R and irradiates.

[0066] The filter 2 is colored with a red pigment such as an azo compound, a cyanine compound, a perylene compound, or a diazine compound, and is formed of a resin that is transparent and has the necessary strength, such as an acrylic resin or a polycarbonate resin. The filter 2 uses such a structure to define at least a part of it, preferably the whole, in the chromaticity range of y ≤ 0.335 and z ≤ 0.008 in the chromaticity coordinates of JIS Z8701. It should be noted that although the filter 2 is called an outer lens, it may have a lens function or may be transparent. In addition, the filter 2 preferably has irregularities (lens cut, microprism) formed on the back surface (inner surface) or the surface in such a way that at least a part of the area becomes a retroreflector.

[0067] (Encapsulation)

[0068] The encapsulation 6 is the outer package that constitutes each of the first light-emitting device 11, the second light-emitting device 12, and the third light-emitting device 13 and supports the light-emitting element 4, and is a resin molded body that houses the first phosphor layer 51, the second phosphor layer 52, and the third phosphor layer 53. In addition, the encapsulation 6 is a light-reflecting component that efficiently emits light upward (toward the irradiation surface side) and emits it at a desired angle centered on the upward direction. The encapsulation 6 has a thin and approximately rectangular parallelepiped shape, and is formed with a recess that expands upward and opens. The encapsulation 6 is formed of a material obtained by adding a light-reflecting substance such as titanium oxide (TiO2) to a resin such as a silicone resin, a modified silicone resin, an epoxy resin, a modified epoxy resin, an acrylic resin, or a mixed resin containing at least one of these resins. In addition, the encapsulation 6 has a pair of lead electrodes for connecting to the light-emitting element 4 and supplying current from the outside.

[0069] (Housing)

[0070] The housing 3 is a box with an opening on the irradiation surface, forming the outer package of the lighting device 10, accommodating the first light-emitting device 11, the second light-emitting device 12, and the third light-emitting device 13, and supporting the filter 2 so as to cover the opening portion. Additionally, the housing 3 is preferably a light reflector with its inner surface as a reflecting surface. With such a housing 3, the emitted light L G 、L Y 、L Ri from the first light-emitting device 11, the second light-emitting device 12, and the third light-emitting device 13 can be efficiently emitted toward the filter 2, and further, the light L W 、L A 、L R can be emitted from the lighting device 10 centered above (the rear of the vehicle) and expanded at a predetermined angle. Additionally, in the housing 3, it is preferable that the first light-emitting device 11, the second light-emitting device 12, and the third light-emitting device 13 are configured to be freely detachable and replaceable individually.

[0071] 〔Operation of the lighting device〕

[0072] Refer to Figure 2 and Figure 3 to describe the operation of the lighting device according to this embodiment. Figure 3 is a chromaticity diagram illustrating the transition of the chromaticity of light based on the filter in the lighting device according to the embodiment.

[0073] Describe the operation of irradiating white light L W . When the blue light L B1 emitted by the first light-emitting element 41 passes through the first phosphor layer 51, at least a part of it is wavelength-converted by the first phosphor in the first phosphor layer 51, and the wavelength-converted light or the light obtained by mixing the wavelength-converted light with the light of the transparent resin that has passed through the first phosphor layer 51 without being wavelength-converted, namely the light L B1 , is emitted as the first light L G from the first light-emitting device 11. Moreover, when the first light L G passes through the filter 2, a part of the light with a wavelength of 410 - 480 nm and at least a part of the light with a wavelength of 500 - 550 nm are absorbed by the filter 2, thereby shifting to white light L W and being irradiated from the lighting device 10. More specifically, since more than 80% of the light with a wavelength of 500 - 550 nm, which is mainly green light, is absorbed by the filter 2, the white light L W is mainly a mixed light of blue-violet to blue to green blue light and yellow to yellowish orange light.

[0074] Here, the light after passing through a red filter that allows relatively more light with a wavelength of 600 - 730 nm to pass through can become the white light L specified in JIS D5500W The chromaticity range before passing through is Figure 3 the area with the shaded line having a downward right diagonal as shown. This is the area containing the complementary color of the orange - red color showing redness with respect to light having a wavelength of 600 to 730 nm. However, since the filter 2 restrictively transmits light with a wavelength less than 600 nm, the light L G before passing through the filter 2 becomes a chromaticity range narrower than the area with the shaded line. Specifically, for the area closer to the negative x - coordinate direction, that is, closer to the monochromatic light locus, the chromaticity shift amount towards the white light L W is large, and it is difficult to become the specified white light L W , and in particular, more than 80% of the light with a wavelength of 500 to 550 nm is absorbed by the filter 2.

[0075] Therefore, the first light L G is preferably set to a bluish - green color or a color close to bluish - green within a chromaticity range with a low excitation purity (chroma) at a dominant wavelength of 485 to 580 nm. Specifically, the chromaticity of the first light L G can be set according to the transmission spectrum of the filter 2 and the target coordinates of the chromaticity of the white light L W . For such a first light L G , as the main emission peak wavelengths in the wavelength range of 380 to 780 nm, it has at least both the emission peak wavelength with the maximum intensity and the emission peak wavelength with no excessive gap therewith, or has one emission peak wavelength with a wide half - value width. And, in order to obtain the light L G with the set chromaticity, as described below, according to the wavelength etc. of the blue light L B1 emitted from the first light - emitting element 41, for the first phosphor layer 51, a phosphor layer having a suitable emission wavelength is selected, and further the wavelength conversion rate of the blue light L B1 is set.

[0076] When the first light L G has two emission peak wavelengths, preferably the emission peak wavelength on the short - wavelength side is 400 nm or more and 480 nm or less, and the emission peak wavelength on the long - wavelength side is 510 nm or more and 580 nm or less. These two emission peak wavelengths are the emission peak wavelengths of the first light - emitting element 41 and the first phosphor layer 51 respectively. In addition, preferably, the longer the emission peak wavelength on the long - wavelength side, the relatively higher the intensity of the emission peak wavelength on the short - wavelength side. In particular, when the emission peak wavelength on the long - wavelength side exceeds 550 nm, preferably the intensity of the emission peak wavelength on the short - wavelength side is high. In addition, for such a first light L G , if the intensity of the emission peak wavelength on the short - wavelength side is high, the extraction efficiency of the white light L W becomes high.

[0077] On the other hand, in the case of the first light L G When there is one emission peak wavelength, the emission peak wavelength is preferably 485 nm or more and 550 nm or less, more preferably 530 nm or less. In addition, the full width at half maximum is preferably 50 nm or more, more preferably 70 nm or more. This emission peak wavelength is the emission peak wavelength of the first phosphor layer 51. By setting the light L to such one emission peak wavelength G , the color spots of the white light L W are less likely to occur. Therefore, it can be said that for the first light L G , regardless of the number of emission peak wavelengths, the emission peak wavelength with the maximum intensity is preferably 400 nm or more and 550 nm or less.

[0078] The operation of irradiating the orange light L A will be described. The blue light L emitted from the second light-emitting element 42 B2 When passing through the second phosphor layer 52, at least a part of it is wavelength-converted by the second phosphor of the second phosphor layer 52, and the wavelength-converted light or the light obtained by mixing the wavelength-converted light and the light that has passed through the transparent resin of the second phosphor layer 52 without being wavelength-converted B2 is emitted from the second light-emitting device 12 as the second light L Y . Moreover, when the second light L Y passes through the filter 2, it becomes orange light L A and is irradiated from the lighting device 10. Since the filter 2 absorbs a part of the light with a wavelength of 410 to 480 nm and at least a part of the light with a wavelength of 500 to 550 nm, when the second light L Y contains the light in these wavelength regions, the color shifts to orange light L A when passing through the filter 2.

[0079] The chromaticity range of the light before passing through the red filter that transmits the light with a wavelength of 600 to 730 nm can become the orange light L specified in JIS D5500 A is the region with the hatched lines slanting upward to the right as shown. However, the more negative the x coordinate and the more positive the y coordinate, that is, the shorter the wavelength, the greater the shift amount to the chromaticity of the orange light L Figure 3 , and the more difficult it is to become the specified orange light L A . In addition, a part of the light with a wavelength of 480 nm or less passes through the filter 2. Therefore, in the hatched region, the light L A before passing through the filter 2 is preferably set to yellow or a color close to yellow in the chromaticity range corresponding to a dominant wavelength of 530 to 590 nm. Y Preferably, the light L

[0080] such as thisY has a peak emission wavelength with the maximum intensity in the wavelength range of 510 to 590 nm as the main peak emission wavelength in the wavelength range of 380 to 780 nm, which is obtained by the blue light L B2 is more obtained by wavelength conversion in the second phosphor layer 52, and most preferably the blue light L B2 is all wavelength-converted. Further, the longer the peak emission wavelength of the light L Y , the higher the extraction efficiency of the orange light L A . On the other hand, if the peak emission wavelength exceeds 550 nm and becomes a longer wavelength, the emission spectrum from the second light L Y to the orange light L A changes little, and the full width at half maximum does not narrow either. Such a second phosphor layer 52 preferably uses a phosphor layer with a full width at half maximum of the emission wavelength that is not too wide. Based on this, the second light L Y becomes the same color as or extremely close to the orange light L A . The chromaticity of the second light L Y can be set according to the transmission spectrum of the filter 2 and the target coordinates of the chromaticity of the orange light L A . And in order to set the light L Y like this, for the second phosphor layer 52, a phosphor layer having a suitable emission wavelength as described above is selected.

[0081] The operation of irradiating the red light L R will be described. The blue light L B3 emitted by the third light-emitting element 43, when passing through the third phosphor layer 53, at least a part is wavelength-converted by the third phosphor in the third phosphor layer 53, and the wavelength-converted light or the light obtained by mixing the wavelength-converted light and the light that passes through the transparent resin of the third phosphor layer 53 without wavelength conversion B3 is emitted from the third light-emitting device 13 as the third light L Ri . Moreover, when the third light L Ri passes through the filter 2, it becomes the red light L R and is irradiated from the lighting device 10. Since the filter 2 allows most of the light with a wavelength of 600 to 730 nm to pass through, the dominant wavelength is difficult to shift from the short wavelength side to the red light L R in the chromaticity range corresponding to 610 to 780 nm. Therefore, in order to obtain the red light L R in a predetermined chromaticity range, the light L Ri before passing through the filter 2 is preferably the same color as or extremely close to the red light L R . Or, the third light L Ri can also be a red-purple color in which the blue light L B3 is absorbed by the filter 2 to almost none.

[0082] Such light L Ri has a main emission peak wavelength with the maximum intensity in the wavelength range of 600 to 700 nm as the main emission peak wavelength at 380 to 780 nm, and is obtained by wavelength conversion of more blue light L B3 in the third phosphor layer 53, and most preferably all blue light L B3 is wavelength-converted. The third light L Ri chromaticity can be set according to the transmission spectrum of the filter 2 and the target coordinates of the chromaticity of the red light L R . In order to set such light L Ri , for the third phosphor layer 53, a phosphor layer having a suitable emission wavelength as described above is selected.

[0083] Thus, in the lighting device 10, the non-white first light L G is shifted to white light L W by the red filter 2 and extracted. On the other hand, the second light L Y and the third light L Ri respectively become the same color or shifted orange light L A , red light L R through the filter 2. In addition, the first light L G is obtained by the combination of the first light-emitting element 41 having a specific emission peak wavelength and the first phosphor layer 51, and thus becomes light having a certain degree or more of intensity in the wavelength ranges of blue light and yellow light respectively. On the other hand, the second light L Y is obtained by the combination of the second light-emitting element 42 and the second phosphor layer 52 having a specific emission peak wavelength, and thus is more stable and easier to control than the light directly emitted from the light-emitting element. Similarly, the third light L Ri is obtained by the combination of the third light-emitting element 43 and the third phosphor layer 53 having a specific emission peak wavelength, and thus is more stable and easier to control than the light directly emitted from the light-emitting element.

[0084] It should be noted that in the lighting device 10, for white light L W , orange light L A , red light L R and the reflected light, it is not limited to the light colors specified in JIS D5500, and can be designed into a desired light color according to the use, and the chromaticity of light L G , L Y , L Ri and the transmission spectrum of the filter 2 can be set as needed.

[0085] The lighting device 10 arranges the first light-emitting device 11, the second light-emitting device 12, and the third light-emitting device 13 on the bottom surface within the housing 3 in regions of a desired shape, so that white light L W , orange light L A , and red light L R are extracted in the shape of each of the aforementioned regions. It should be noted that the array pitches of the first light-emitting device 11, the second light-emitting device 12, and the third light-emitting device 13 do not have to be the same. In particular, for more than about 80% of the third light L Ri that passes through the filter 2, since most of the first light L G is absorbed, the light quantity attenuation from the first light L G to the white light L W is very large. Therefore, it is preferable to design the quantity, array pitch, or brightness of the light-emitting elements 4 installed in each of the first light-emitting device 11, the second light-emitting device 12, and the third light-emitting device 13 so that white light L W , orange light L A , and red light L R can be extracted with the necessary light quantity respectively.

[0086] In addition, in the lighting device 10, in order to prevent the mixing of white light L W , orange light L A , and red light L R , it is preferable to set a structure in which two or more of the optical paths of the first light L G , the second light L Y , and the third light L Ri do not overlap before passing through the filter 2. Specifically, the intervals between the first light-emitting device 11 and the third light-emitting device 13, the intervals between the second light-emitting device 12 and the third light-emitting device 13, etc. are arranged separately. Alternatively, a partition may be provided between the region where the first light-emitting device 11 is arranged and the region where the third light-emitting device 13 is arranged, between the region where the second light-emitting device 12 is arranged and the region where the third light-emitting device 13 is arranged, etc. Or, for example, when the white light L W and the red light L R are lit simultaneously, at least one of the first light-emitting device 11 and the third light-emitting device 13 may also be designed such that a part arranged near the boundary between the regions where they are respectively arranged is not lit. On the other hand, in the lighting device 10, by arranging two or more different types of the first light-emitting device 11, the second light-emitting device 12, and the third light-emitting device 13 close to each other and mixed together, it is possible to select only any one of them to be lit, and it becomes a structure that alternately irradiates white light L W , orange light L A , and red light L R from one region.

[0087] (Modification Example)

[0088] The housing 3 may also be shaped such that it is divided for each region where the first light-emitting device 11, the second light-emitting device 12, and the third light-emitting device 13 are respectively arranged. By using the housing 3, a wall having a reflecting surface is provided between the regions, thereby facilitating the control of the white light L W , orange light L A , red light L R The respective irradiation directions. In addition, the light extraction efficiency is increased. In addition, the bottom surface inside the housing 3 does not have to be a flat surface. For example, it may be configured such that each region has a convex surface bulging in the center, and the light L G , L Y , L Ri is emitted widely from each group of the first light-emitting device 11, the second light-emitting device 12, and the third light-emitting device 13 arranged on such a bottom surface.

[0089] In addition, the first phosphor layer 51, the second phosphor layer 52, and the third phosphor layer 53 (when not specifically specified, referred to as the phosphor layer 5) may also be formed by molding based on a mold, etc. For example, it may be formed into a dome shape that covers the light-emitting element 4 mounted on the flat package 6 (wiring substrate 6A). In addition, the phosphor layer 5 may not be a sealing member for the light-emitting element 4, but a plate material obtained by coating a transparent resin in which phosphors are dispersed on a transparent substrate such as glass by potting, printing, spraying, etc. Or, the phosphor layer 5 may be a plate material formed by aggregating particles in an organic solvent and coagulating them on the light-emitting element 4 or a plate material fired together with an inorganic material such as glass. With the phosphor layer 5 having such a structure not dispersed in the resin, the wavelength conversion efficiency of the blue light L B is increased, and in addition, it is easy to suppress the light spots of the light L G , L Y , L Ri . It should be noted that the plate-shaped phosphor layer 5 can be formed in such a way that it is bonded to the upper surface of the light-emitting element 4 using a transparent resin or the like. In this case, it is preferable to cover the side surface of the light-emitting element 4 with a resin added with a light-reflective substance to prevent the leakage of the blue light L B . Or, as in the modification example described later, the plate-shaped phosphor layer 5 can also be formed in such a way that it is fixed on the upper side of the light-emitting element 4 after installation.

[0090] In the lighting device 10, although one light-emitting element 4 is installed in each of the first light-emitting device 11, the second light-emitting device 12, and the third light-emitting device 13, this is not limiting, and a surface light-emitting device in which a plurality of light-emitting elements 4 are arranged and installed may be provided in each region. Hereinafter, with reference to Figure 4 The structure of the lighting device according to the modification example of the embodiment of the present invention will be described. Figure 4It is a cross-sectional view that magnifies and schematically shows a partial structure of the lighting device according to a modified example of the embodiment.

[0091] The lighting device 10A includes: a first light-emitting device 11A having a first phosphor layer 51A and a plurality of first light-emitting elements 41; a second light-emitting device 12A having a second phosphor layer 52A and a plurality of second light-emitting elements 42; and a third light-emitting device 13A having a third phosphor layer 53A and a plurality of third light-emitting elements 43. They are individually housed in the housing 3, and a filter 2 is fixed to the upper surface of the lighting device 10A so as to close the opening of the housing 3. Further, the first light-emitting device 11A, the second light-emitting device 12A, and the third light-emitting device 13A each have a wiring substrate 6A and a housing 7. Additionally, as needed, it may also have a transparent resin that seals the light-emitting element 4 and is filled inside the housing 7. In the first light-emitting device 11A, a plurality of first light-emitting elements 41 are arranged and mounted on the wiring substrate 6A. Further, the housing 7 bonded to the peripheral portion of the wiring substrate 6A supports one first phosphor layer 51A. The second light-emitting device 12A and the third light-emitting device 13A have the same structure as the first light-emitting device 11A. The first phosphor layer 51A, the second phosphor layer 52A, and the third phosphor layer 53A are, as described above, plates obtained by firing a phosphor having a predetermined emission peak wavelength together with an inorganic material. The wiring substrate 6A, like the package 6, is a base that supports the light-emitting element 4 and has lead electrodes. The housing 7 is provided so that the blue light L B does not directly reach the filter 2 from the light-emitting element 4, and preferably has a structure that reflects light together with the wiring substrate 6A.

[0092] Further, the lighting device 10 may also have a structure, for example, having a desired number of first light-emitting devices 11 and second light-emitting devices 12 and one third light-emitting device 13A. Additionally, the lighting device 10 may also have only the first light-emitting device 11, and when turned off, it becomes a reflector that reflects red light from at least a part of the irradiation surface, and can be used as a lighting device for white light L W Or, the lighting device 10 may have both the first light-emitting device 11 and the second light-emitting device 12 or the third light-emitting device 13 according to the use, and become a device that irradiates white light L W and orange light L A or white light L W and red light L RThe structure of two-color light. That is, the lighting device 10 has: two or more phosphor layers including at least one of the second phosphor layer 52 and the third phosphor layer 53 and the first phosphor layer 51; a light-emitting element 4 provided at each position where light enters for each phosphor layer; and a filter 2 provided at a position where light emitted from each phosphor layer enters. Similarly, for the lighting device 10A, it may also be a structure having only the first light-emitting device 11A, or a structure having both the first light-emitting device 11A and the second light-emitting device 12A or the third light-emitting device 13A.

[0093] As described above, the lighting device according to the embodiment of the present invention combines a light-emitting element that emits blue light with phosphors having specific emission wavelengths, so that even if a red cover is provided on the irradiation surface, white light can be emitted. Further, by having a combination of phosphors such as yellow-based and red-based phosphors and light-emitting elements, at least a part of the irradiation surface can be used as a red reflector, and white light, orange light, and red light of a specified light color can be irradiated as signal lights and display lights for automobiles. Therefore, it can be used as a lighting device that irradiates a desired color-matching pattern of light by arranging light-emitting elements or the like without color-separating the cover.

[0094] [Examples]

[0095] Hereinafter, as an example of the present invention, a sample simulating the lighting device according to the embodiment was prototyped to confirm its effect. In the example, three light-emitting devices that emit light before passing through the filter were fabricated, and the emission spectra of the light extracted before and after passing through the filter were measured. Figure 5 、 Figure 6 and Figure 7 is a graph showing the transmission spectrum of the filter and the emission spectra before and after passing through the filter in the lighting device according to the example, Figure 5 is white light, Figure 6 is orange light, Figure 7 is red light. Figure 8 is a chromaticity diagram showing the chromaticity coordinates before and after passing through the filter in the lighting device according to the example.

[0096] (Fabrication of Sample)

[0097] A chip of an LED having an emission peak wavelength of the emission spectrum of 445 nm was used as a common light-emitting element. A chlorosilicate phosphor (Ca8MgSi4O with an emission peak wavelength of the emission spectrum of 520 nm added with 27 phr 16The light-emitting element was sealed with a silicone resin containing 150 phr of YAG phosphor with a luminescent peak wavelength of 550 nm, and a sample 2 of the light-emitting device was prepared. The light-emitting element was sealed with a silicone resin containing 120 phr of CASN phosphor with a luminescent peak wavelength of 660 nm, and a sample 3 of the light-emitting device was prepared. Figures 5 - 7 A red filter that transmits the light spectrum is shown as a filter (CF).

[0098] (evaluate)

[0099] For samples 1, 2, and 3, the light-emitting elements were made to emit light, and the light spectrum, chromaticity, and beam were measured. Next, the light after passing through the filter was measured in the same manner. The chromaticity and the light flux are shown in Table 1. Figure 5 , Figure 6 and Figure 7 The intensities of the emission spectra are shown as relative values ​​of the respective samples.

[0100] [Table 1]

[0101]

[0102] The light emitted from sample 1 has a peak emission wavelength with the maximum intensity at a wavelength of 520nm due to the phosphor, and also has a strong peak emission wavelength at a wavelength of 445nm due to the light emission of the light emitting element, and exhibits a bluish green color. When the light passes through the filter, about 15 to 25% of the light with a wavelength of 420 to 480nm is absorbed by the filter, and the peak emission wavelength at a wavelength of 445nm becomes weaker. In addition, about 90% or more of the light with a wavelength of 500 to 550nm is absorbed for the peak emission wavelength with the maximum intensity, which is greatly weakened, and the intensity becomes the same as the peak emission wavelength at a wavelength of 445nm, and the peak emission wavelength shifts to about 580nm. As a result, the white light obtained by mixing the purple blue and yellowish orange becomes a color, and the chromaticity x of the light is shifted in the positive direction and y is shifted in the negative direction relative to before passing through the filter, reaching the chromaticity range specified in JIS D5500.

[0103] The light emitted from Sample 2 has a peak emission wavelength with a maximum intensity at a wavelength of 550 nm by using a phosphor. On the other hand, the intensity of the peak emission wavelength at a wavelength of 445 nm caused by the emission of the light-emitting element is extremely weak, presenting a yellowish green with a dominant wavelength of approximately 570 nm. When this light passes through the filter, the light with wavelengths of 420 to 480 nm is absorbed by the filter, and the peak emission wavelength at a wavelength of 445 nm is no longer observed. In addition, for the peak emission wavelength with the maximum intensity, more than about 90% of the light with wavelengths of 500 to 550 nm is absorbed. On the other hand, more than about 80% of the light with wavelengths of 595 nm or more passes through. As a result, the half-value width becomes narrower, the peak emission wavelength shifts to approximately 595 nm, and the intensity decreases. As a result, it becomes orange light shown by this peak emission wavelength, and the excitation purity becomes higher. Compared with before passing through the filter, the chromaticity x of the light shifts in the positive direction and y shifts in the negative direction, reaching the chromaticity range specified by JIS D5500.

[0104] The light emitted from Sample 3 has a peak emission wavelength at a wavelength of 660 nm by using a phosphor. On the other hand, the peak emission wavelength at a wavelength of 445 nm is not observed, becoming red light with a dominant wavelength of approximately 625 nm, reaching the chromaticity range specified by JIS D5500. When this light passes through the filter, more than about 90% of the light with wavelengths of 615 nm or more passes through. As a result, the peak emission wavelength does not shift, and the decrease in intensity is also very slight. As a result, the chromaticity of the light hardly shifts, and after passing through the filter, it also reaches the chromaticity range specified by JIS D5500.

[0105] Comparing the changes in the light of Sample 1 and Sample 2 before and after passing through the filter, it can be seen that the difference in the shift direction and shift amount of the chromaticity is small. However, the light quantity of Sample 1 is significantly attenuated.

[0106] By setting the emission wavelength of the phosphor and the transmission spectrum of the filter within a predetermined range, white light, orange light, and red light can be made to pass through and extracted from the same filter.

[0107] Industrial Applicability

[0108] The lighting device according to the present invention can be used in the rear combination lamp of an automobile.

Claims

1. A lighting device, characterized in that, the lighting device has: a first light-emitting element having a light-emitting peak wavelength in the range of 400 nm or more and 510 nm or less; a first phosphor disposed at a position where light emitted from the first light-emitting element is incident, and excited by the light to have a light-emitting peak wavelength in the range of 485 nm or more and 700 nm or less; and a filter having a light transmittance of 80% or more for light with a wavelength of 600 nm or more and 730 nm or less, and a maximum transmittance, i.e., the maximum transmittance among the light transmittances in the range of 410 nm or more and 480 nm or less, of 20% or more. The filter is disposed at a position where the first light is incident, and transmits a part of the first light, and the first light is composed of light emitted from the first light-emitting element and light emitted from the first phosphor, the filter is an outer lens for an automotive lamp, the first light after passing through the filter is white.

2. The lighting device according to claim 1, characterized in that, the filter is red.

3. The lighting device according to claim 1, characterized in that, at least a part of the filter has a chromaticity range of y ≤ 0.335 and z ≤ 0.008 in the chromaticity coordinates of JIS Z8701.

4. The lighting device according to claim 1, characterized in that, the first light after passing through the filter has a chromaticity range of 0.500 ≥ x ≥ 0.310, y ≤ 0.150 + 0.640x, y ≥ 0.050 + 0.750x, and 0.440 ≥ y ≥ 0.382 in the chromaticity coordinates of JIS Z8701.

5. The lighting device according to claim 2 or 3, characterized in that, the first light after passing through the filter has a chromaticity range of 0.500 ≥ x ≥ 0.310, y ≤ 0.150 + 0.640x, y ≥ 0.050 + 0.750x, and 0.440 ≥ y ≥ 0.382 in the chromaticity coordinates of JIS Z8701.

6. The lighting device according to claim 1 or 4, characterized in that, the first phosphor is a chlorosilicate phosphor.

7. The lighting device according to claim 1 or 4, characterized in that, the lighting device further has: a second light-emitting element having a light-emitting peak wavelength in the range of 400 nm or more and 510 nm or less; and a second phosphor disposed at a position where light emitted from the second light-emitting element is incident, and excited by the light to have a light-emitting peak wavelength in the range of 510 nm or more and 590 nm or less, the filter is disposed at a position where the second light is incident, and transmits at least a part of the second light, and the second light is composed of light emitted from the second light-emitting element and light emitted from the second phosphor.

8. The lighting device according to claim 7, characterized in that, The second light after passing through the filter has a chromaticity range of 0.429 ≥ y ≥ 0.398 and z ≤ 0.007 in the chromaticity coordinates of JIS Z8701.

9. The lighting device according to claim 7, wherein the second phosphor is a YAG phosphor.

10. The lighting device according to claim 8, wherein the second phosphor is a YAG phosphor.

11. The lighting device according to claim 1 or 4, wherein the lighting device further comprises: a third light-emitting element having a light emission peak wavelength of 400 nm or more and 510 nm or less; and a third phosphor disposed at a position where the light emitted from the third light-emitting element is incident, and excited by the light to have a light emission peak wavelength of 600 nm or more and 700 nm or less, the filter is disposed at a position where the third light is incident, and transmits at least a part of the third light, the third light being composed of the light emitted from the third light-emitting element and the light emitted from the third phosphor.

12. The lighting device according to claim 11, wherein the third light after passing through the filter has a chromaticity range of y ≤ 0.335 and z ≤ 0.008 in the chromaticity coordinates of JIS Z8701.

13. The lighting device according to claim 11, wherein the third phosphor is a CASN phosphor.

14. The lighting device according to claim 12, wherein the third phosphor is a CASN phosphor.

15. The lighting device according to claim 7, wherein the lighting device further comprises: a third light-emitting element having a light emission peak wavelength of 400 nm or more and 510 nm or less; and a third phosphor disposed at a position where the light emitted from the third light-emitting element is incident, and excited by the light to have a light emission peak wavelength of 600 nm or more and 700 nm or less, the filter is disposed at a position where the third light is incident, and transmits at least a part of the third light, the third light being composed of the light emitted from the third light-emitting element and the light emitted from the third phosphor.

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