JP2013089769A - Light emitting module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting module that emits light with high color rendering properties.SOLUTION: A light emitting module 10 comprises: a semiconductor light emitting element 18 emitting ultraviolet light or short-wavelength visible light; a first phosphor excited by the ultraviolet light or the short-wavelength visible light and emitting the visible light; a second phosphor excited by the ultraviolet light or the short-wavelength visible light and emitting the visible light which is complementary color to the visible light emitted from the first phosphor; and a third phosphor excited by the ultraviolet light or the short-wavelength visible light and emitting the visible light which has a peak wavelength between the peak wavelength in the visible light emitted from the first phosphor and the peak wavelength in the visible light emitted from the second phosphor. When the intensity of the excitation spectrum in the peak wavelength of the emission spectrum of the light emitting element is represented by Ia and the intensity of the excitation spectrum in the peak wavelength of the emission spectrum of the first or second phosphor is represented by Ib, the third phosphor satisfies Ib<Ia×0.15.

Description

  The present invention relates to a light emitting module using a phosphor, and, for example, to a light emitting module using a phosphor that is efficiently excited and emitted by ultraviolet light or short wavelength visible light.

  Various light-emitting elements configured to obtain light of a desired color by combining a light-emitting element and a phosphor that is excited by light generated by the light-emitting element and generates light having a wavelength region different from that of the light-emitting element. The device is known.

  In particular, in recent years, as a white light emitting device with long life and low power consumption, semiconductor light emitting diodes such as light emitting diodes (LED) and laser diodes (LD) that emit ultraviolet light or short wavelength visible light, and phosphors using these as light sources for excitation A light-emitting device configured to obtain white light by combining the above is drawing attention.

  As a specific example of such a white light emitting device, there is known a method of combining a plurality of phosphors that emit violet light or ultraviolet light, and phosphors that are excited by violet light or ultraviolet light and emit light of a color such as blue or yellow. (See Patent Document 1).

JP 2009-38348 A

  However, a white LED that combines a yellow phosphor and a blue phosphor and an LED that emits purple light or ultraviolet light does not have sufficient color rendering properties, and there is room for further improvement when used as general illumination.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a light emitting module having high color rendering properties.

  In order to solve the above problems, a light emitting module according to an aspect of the present invention includes a light emitting element that emits ultraviolet light or short wavelength visible light, and a first phosphor that emits visible light when excited by ultraviolet light or short wavelength visible light. Excited by ultraviolet light or short-wavelength visible light and excited by ultraviolet light or short-wavelength visible light; a second phosphor that emits visible light complementary to the visible light emitted by the first phosphor; A third phosphor that emits visible light and has a peak wavelength between the peak wavelength of visible light emitted by the first phosphor and the peak wavelength of visible light emitted by the second phosphor. When the intensity of the excitation spectrum at the peak wavelength of the emission spectrum of the light emitting element is Ia and the intensity of the excitation spectrum at the peak wavelength of the emission spectrum of the first phosphor or the second phosphor is Ib, Ib <Ia × 0.15 is satisfied.

  Since the visible light emitted from the first phosphor and the visible light emitted from the second phosphor are complementary to each other, white light can be obtained. However, it is often difficult to obtain white light having high color rendering properties only by mixing two colors of light that are complementary to each other. Therefore, according to this aspect, the third phosphor has a peak wavelength between the peak wavelength of visible light emitted from the first phosphor and the peak wavelength of visible light emitted from the second phosphor. Since visible light is emitted, white light with higher color rendering can be realized. The third phosphor has an excitation spectrum intensity Ia at the peak wavelength of the emission spectrum of the light emitting element, Ia, and an excitation spectrum intensity at the peak wavelength of the emission spectrum of the first phosphor or the second phosphor as Ib. Then, it is configured to satisfy Ib <Ia × 0.15. For this reason, the third phosphor is less excited by the light emitted from the first phosphor or the second phosphor, and color shift can be suppressed.

The third phosphor has a general formula represented by Cs ₂ Sr _1-x P ₂ O ₇ : Eu ²⁺ _x (where x may be in a range of 0 <x ≦ 0.3). It may be. Further, the third phosphor may have a peak wavelength of its emission spectrum in a wavelength region of 500 to 580 nm. Thereby, white light with high color rendering can be realized.

The first phosphor has a general formula of M ¹ O ₂ .aM ² O.bM ³ X ₂ : M ⁴ _c (where M ¹ is at least 1 selected from the group consisting of Si, Ge, Ti, Zr and Sn) seed elements, ^{M 2} is Mg, Ca, Sr, at least one element selected from the group consisting of Ba and Zn, ^{M 3} is Mg, Ca, Sr, at least one selected from the group consisting of Ba, and Zn Element, X is at least one halogen element, M ⁴ is at least one element essential to Eu ²⁺ selected from the group consisting of rare earth elements and Mn, a is 0.1 ≦ a ≦ 1.3, b may be in a range of 0.1 ≦ b ≦ 0.25. Thereby, the 1st fluorescent substance with a more favorable light emission characteristic is obtained.

  When the intensity of the excitation spectrum at the peak wavelength of the emission spectrum of the light emitting element is Ic and the intensity of the excitation spectrum at the peak wavelength of the emission spectrum of the second phosphor is Id, the first phosphor has Id <Ic × 0. 30 may be satisfied. As a result, the first phosphor is less excited by the light emitted by the second phosphor, and color shift can be suppressed.

  The light emitting element may emit ultraviolet light or short wavelength visible light having a peak wavelength in a wavelength range of 350 to 420 nm.

  It should be noted that any combination of the above-described constituent elements and a representation obtained by converting the expression of the present invention between a method, an apparatus, a system, and the like are also effective as an aspect of the present invention.

  According to the present invention, a light emitting module having high color rendering properties can be provided.

It is a schematic sectional drawing of the light emitting module which concerns on this Embodiment. It is a figure which shows the emission spectrum of the fluorescent substance 1. It is a figure which shows the emission spectrum of the fluorescent substance 2. It is a figure which shows the emission spectrum of the fluorescent substance 3. It is a figure which shows the emission spectrum of the fluorescent substance 4. It is a figure which shows the emission spectrum of the fluorescent substance 5. It is a figure which shows the emission spectrum of the fluorescent substance 6. It is a figure which shows the excitation spectrum (line L1) of the fluorescent substance 6, and the emission spectrum (line L2) of the blue fluorescent substance which is a 2nd fluorescent substance. It is a figure which shows the excitation spectrum (line L3) of the fluorescent substance 1, and the emission spectrum (line L2) of the blue fluorescent substance which is a 2nd fluorescent substance. It is a figure which shows the emission spectrum of the light emitting module which concerns on Example 1, and the emission spectrum of the light emitting module which concerns on the comparative example 1. It is a figure which shows the emission spectrum of the light emitting module which concerns on Example 2. FIG. It is a figure which shows the emission spectrum of the light emitting module which concerns on Example 3. FIG. It is a figure which shows the emission spectrum of the light emitting module which concerns on Example 4. FIG. It is a figure which shows the emission spectrum of the light emitting module which concerns on Example 5. FIG.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate.

  FIG. 1 is a schematic cross-sectional view of the light emitting module according to the present embodiment. In the light emitting module 10 shown in FIG. 1, a pair of electrodes 14 (anode) and an electrode 16 (cathode) are formed on a substrate 12. A semiconductor light emitting element 18 is fixed on the electrode 14 by a mount member 20. The semiconductor light emitting element 18 and the electrode 14 are electrically connected by a mount member 20, and the semiconductor light emitting element 18 and the electrode 16 are electrically connected by a wire 22. A phosphor filter 24 is installed on the emission surface of the semiconductor light emitting device.

  The substrate 12 is preferably formed of a material having no electrical conductivity but high thermal conductivity. For example, a ceramic substrate (aluminum nitride substrate, alumina substrate, mullite substrate, glass ceramic substrate), a glass epoxy substrate, or the like is used. be able to.

  The electrodes 14 and 16 are conductive layers formed of a metal material such as gold or copper.

  The semiconductor light emitting element 18 is an example of a light emitting element used in the light emitting module of the present invention, and for example, an LED or LD that emits ultraviolet light or short wavelength visible light can be used. Specific examples include InGaN-based compound semiconductors. The emission wavelength range of the InGaN-based compound semiconductor varies depending on the In content. When the In content is large, the emission wavelength becomes long, and when it is small, the wavelength tends to be short. However, the InGaN-based compound semiconductor containing In at such an extent that the peak wavelength is around 400 nm is a quantum efficiency in light emission. Has been confirmed to be the highest.

  The mount member 20 is, for example, a conductive adhesive such as silver paste or gold-tin eutectic solder, and the lower surface of the semiconductor light emitting element 18 is fixed to the electrode 14. The electrode 14 is electrically connected.

  The wire 22 is a conductive member such as a gold wire, and is joined to the upper surface side electrode and the electrode 16 of the semiconductor light emitting element 18 by, for example, ultrasonic thermocompression bonding, and electrically connects both.

  In the phosphor filter 24, each phosphor described later is dispersed in a binder member. The phosphor filter 24 is prepared, for example, by preparing a phosphor paste in which a phosphor is mixed in a liquid or gel binder member, and then applying the phosphor paste to the upper surface of the optical glass to a predetermined film thickness, and thereafter It is formed by curing the binder member of the paste. As the binder member, for example, a silicone resin or a fluorine resin can be used. Moreover, since the light emitting module according to the present embodiment uses ultraviolet light or short wavelength visible light as an excitation light source, a binder member having excellent ultraviolet resistance is preferable.

  The phosphor filter 24 may be mixed with substances having various physical properties other than the phosphor. A substance having a higher refractive index than that of the binder member, such as a metal oxide, a fluorine compound, or a sulfide, is mixed into the phosphor filter 24, whereby the refractive index of the phosphor filter 24 can be increased. Thereby, the total reflection that occurs when the light generated from the semiconductor light emitting element 18 enters the phosphor filter 24 is reduced, and the effect of improving the efficiency of capturing excitation light into the phosphor filter 24 is obtained. Furthermore, the refractive index can be increased without reducing the transparency of the phosphor filter 24 by making the particle size of the mixed substance nano-sized. In addition, white powder having an average particle size of about 0.3 to 3 μm, such as alumina, zirconia, and titanium oxide, can be mixed in the phosphor filter 24 as a light scattering agent. Thereby, uneven brightness and chromaticity in the light emitting surface can be prevented.

  Next, each phosphor used in the light emitting module according to the present embodiment will be described in detail.

(First phosphor)
The first phosphor according to the present embodiment is a yellow light emitting phosphor. As a suitable example of a yellow light-emitting phosphor (hereinafter referred to as “yellow phosphor”), the general formula is M ¹ O ₂ .aM ² O.bM ³ X ₂ : M ⁴ _c (where M ¹ is Si, Ge, Ti, at least one element of at least one element selected from the group consisting of Zr and Sn, ^{M 2} is Mg, Ca, Sr, selected from the group consisting of Ba and Zn, ^{M 3} is Mg, Ca, At least one element selected from the group consisting of Sr, Ba and Zn, X is at least one halogen element, M ⁴ is at least one element essential to Eu ²⁺ selected from the group consisting of rare earth elements and Mn A is in the range of 0.1 ≦ a ≦ 1.3, and b is in the range of 0.1 ≦ b ≦ 0.25. The yellow phosphor is excited by ultraviolet rays or short-wavelength visible light, and emits visible light that realizes white by mixing with visible light emitted by the blue phosphor. More specifically, the yellow phosphor emits visible light having a peak wavelength in a wavelength range of 560 to 600 nm.

In addition, as a yellow fluorescent substance mentioned above, a more preferable aspect is as follows when represented by a general formula.
(Ca _1-x , Sr _x ) ₇ (SiO ₃ ) ₆ Cl ₂ : Eu ²⁺ (where 0 <x <1)

(Second phosphor)
The second phosphor according to the present embodiment is a blue light emitting phosphor. A suitable example of a blue light-emitting phosphor (hereinafter referred to as “blue phosphor”) is a Ca apatite phosphor. The Ca apatite phosphor is represented by the general formula (Ca _5−xy , Mg _x ) (PO ₄ ) ₃ Cl: Eu ²⁺ _y .

Moreover, Sr apatite fluorescent substance is mentioned as another suitable example of blue fluorescent substance. The Sr apatite phosphor is represented by the general formula (Sr _5-y ) (PO ₄ ) ₃ Cl: Eu ²⁺ _y .

Further, another suitable example of the blue phosphor is a CaSr apatite phosphor. CaSr apatite phosphor has the general formula _{(Ca 5-x-y,} Sr x) (PO 4) 3 Cl: represented by ^{Eu 2+} _y.

Moreover, a BAM fluorescent substance is mentioned as another suitable example of a blue fluorescent substance. The BAM phosphor is represented by a general formula BaMgAl ₁₀ O ₁₇ : Eu ²⁺ .

(Third phosphor)
The third phosphor according to the present embodiment is a green light emitting phosphor. A suitable example of the green light emitting phosphor (hereinafter referred to as “green phosphor”) is a general formula Cs ₂ Sr _1-x P ₂ O ₇ : Eu ²⁺ _x (where x is 0 <x ≦ 0). .3 range)). The third phosphor may have a peak wavelength of its emission spectrum in a wavelength range of 500 to 580 nm. Thereby, white light with high color rendering can be realized.

  Hereinafter, the present embodiment will be described more specifically with reference to examples. Each phosphor used in the examples was prepared by the following method.

<Phosphor 1>
The phosphor 1 is a phosphor represented by the general formula (Ca _1-x , Sr _x ) ₇ (SiO ₃ ) ₆ Cl ₂ : Eu ²⁺ (where 0 <x <1). This is an example of the first phosphor. The adjustment method of the phosphor 1 is as follows.

First, SiO ₂ (Kojundo Chemical Laboratory Co. _{SIO01CB), SrCl 2 · 6H 2} O ( manufactured by the same company _{SRH04XB), SrCO 3, Ca (} OH) 2 ( manufactured by the same company CAH08PB) and _Eu 2 _{O 3} (manufactured by the same company EUO01PB) Each of these raw materials has a molar ratio of SiO ₂ : SrCl ₂ .6H ₂ O: SrCO ₃ : Ca (OH) ₂ : Eu ₂ O ₃ = 1.00: 0.94: 0.09: 0.29: It weighed so that it might be set to 0.14, each weighed raw material was pulverized and mixed in an alumina mortar for about 30 minutes in the air to obtain a raw material mixture. This raw material mixture was put into an alumina crucible and fired at a predetermined atmosphere (N ₂ atmosphere containing 5% H ₂ ) in a reducing atmosphere electric furnace at a temperature of 1000 ° C. for 4 to 10 hours to obtain a fired product. The obtained fired product was carefully washed with warm pure water, and excess chloride was washed away to obtain phosphor 1. FIG. 2 is a diagram showing an emission spectrum of the phosphor 1. The excitation light source is an LED that emits ultraviolet light or short-wavelength visible light and has an emission spectrum with a peak wavelength of 405 nm. The same applies to each of the examples and comparative examples shown in FIGS.

<Phosphor 2>
The phosphor 2 is a phosphor represented by the general formula (Ca _5−x−y , Mg _x ) (PO ₄ ) ₃ Cl: Eu ²⁺ _y , and is an example of the second phosphor described above. The adjustment method of the phosphor 2 is as follows.

First, CaCO ₃ (CAH08PB manufactured by High Purity Chemical Laboratory Co., Ltd.), MgCO ₃ (manufactured by Hakuho Chemical Co., Ltd.), Eu ₂ O ₃ (EUO01PB manufactured by High Purity Chemical Laboratory Co., Ltd.), CaCl ₂ (CAH06XB manufactured by the same company) and (NH ₄ ) H ₂ (PO ₄ ) (01309-00 manufactured by Kanto Chemical Co., Inc.), the molar ratio of which is CaCO ₃ : MgCO ₃ : Eu ₂ O ₃ : CaCl ₂ : (NH ₄ ) H ₂ (PO ₄ ) = 2.9: 1.5: 0.05: 0.5: 3.0 Weighed to uniform, and after uniform mixing, calcined in an alumina crucible at 800-1000 ° C. for 3 hours. Thereafter, the fired product is pulverized in a mortar, and the pulverized product and (NH ₄ ) Cl are mixed in a mortar, and then in an N ₂ atmosphere containing ₂ to 5% H ₂ in an alumina crucible with a lid, Phosphor 2 was synthesized by firing for 3 hours. FIG. 3 is a diagram showing an emission spectrum of the phosphor 2.

<Phosphor 3>
The phosphor 3 is a phosphor represented by the general formula (Sr _5-y ) (PO ₄ ) ₃ Cl: Eu ²⁺ _y , and is an example of the second phosphor described above. The adjustment method of the phosphor 3 is as follows.

First, SrCO ₃ (SRH08PB manufactured by High Purity Chemical Laboratory), Eu ₂ O ₃ (manufactured EUO01PB), CaCl ₂ (manufactured CAH06XB) and (NH ₄ ) H ₂ (PO ₄ ) (manufactured by Kanto Chemical Co., Ltd. 01309- 00), the molar ratio of these is SrCO ₃ : Eu ₂ O ₃ : CaCl ₂ : (NH ₄ ) H ₂ (PO ₄ ) = 4.98: 0.01: 0.5: 3.0 After weighing and uniform mixing, firing is performed at 800 to 1000 ° C. for 3 hours in an alumina crucible. Thereafter, the fired product is pulverized in a mortar, and the pulverized product and (NH ₄ ) Cl are mixed in a mortar, and then in an N ₂ atmosphere containing ₂ to 5% H ₂ in an alumina crucible with a lid, The phosphor 3 was synthesized by firing for 3 hours. FIG. 4 is a diagram showing an emission spectrum of the phosphor 3.

<Phosphor 4>
The phosphor 4 is a phosphor represented by the general formula (Ca _5−x−y , Sr _x ) (PO ₄ ) ₃ Cl: Eu ²⁺ _y , and is an example of the second phosphor described above. The adjustment method of the phosphor 4 is as follows.

First, CaCO ₃ (CAH08PB manufactured by High Purity Chemical Laboratory Co., Ltd.), SrCO ₃ (manufactured by Shirahige Chemical), Eu ₂ O ₃ (manufactured EUO01PB), CaCl ₂ (manufactured CAH06XB) and (NH ₄ ) H ₂ (PO ₄ ) Each raw material of (01309-00 manufactured by Kanto Chemical Co., Inc.) has a molar ratio of CaCO ₃ : SrCO ₃ : Eu ₂ O ₃ : CaCl ₂ : (NH ₄ ) H ₂ (PO ₄ ) = 3.5: 1.4: 0.05: 0.5: 3.0 are weighed, and after uniform mixing, calcined in an alumina crucible at 800-1000 ° C. for 3 hours. Thereafter, the fired product is pulverized in a mortar, and the pulverized product and (NH ₄ ) Cl are mixed in a mortar, and then in an N ₂ atmosphere containing ₂ to 5% H ₂ in an alumina crucible with a lid, The phosphor 4 was synthesized by firing for 3 hours. FIG. 5 is a diagram showing an emission spectrum of the phosphor 4.

<Phosphor 5>
The phosphor 5 is a phosphor represented by the general formula BaMgAl ₁₀ O ₁₇ : Eu ²⁺ and is an example of the second phosphor described above. The adjustment method of the phosphor 5 is as follows.

First, the raw materials of BaCO ₃ (BAH07PB manufactured by High Purity Chemical Laboratory), Eu ₂ O ₃ (manufactured EUO01PB), MgCO ₃ (manufactured MGH04XB) and α-Al ₂ O ₃ (manufactured ALO04RB) The molar ratio is BaCO ₃ : Eu ₂ O ₃ : MgCO ₃ : α-Al ₂ O ₃ = 0.9: 0.05: 1.0: 5.0, and AlF ₃ ( ALH07PB) made by the same company is weighed 0.5% in molar ratio with respect to α-Al ₂ O _{3 and} after uniform mixing, it is fired in an alumina crucible at 1500 ° C. for 3 hours in a reducing atmosphere. 5 was synthesized. FIG. 6 is a diagram showing an emission spectrum of the phosphor 5.

<Phosphor 6>
The phosphor 6 is a phosphor represented by the general formula Cs ₂ Sr _1-x P ₂ O ₇ : Eu ²⁺ _x (where x is in the range of 0 <x ≦ 0.3). It is an example of the above-mentioned 3rd fluorescent substance. The adjustment method of the phosphor 6 is as follows.

First, (NH ₄ ) ₂ HPO ₄ (manufactured by Kanto Chemical Co., Inc.), Eu ₂ O ₃ (EUO01PB manufactured by High Purity Chemical Laboratory Co., Ltd.), Cs ₂ CO ₃ (manufactured by the company CSH08XB), SrCO ₃ (manufactured by Hakuho Chemical) Each powder was weighed to have the chemical formula Cs ₂ Sr _0.99 P ₂ O ₇ : Eu ²⁺ _0.01, and after uniform mixing, calcined in an alumina crucible with a lid at a temperature of 300 ° C. Thereafter, the phosphor 6 was synthesized by baking at 800 ° C. for 5 hours in an N ₂ atmosphere containing ₂ to 5% H ₂ . FIG. 7 is a diagram showing an emission spectrum of the phosphor 6. The phosphor 6 is a green light-emitting phosphor having a peak wavelength λp = 554 nm.

  By the way, when using a plurality of phosphors, one of the phosphors having the shortest peak wavelength is excited by the excitation light emitted from the light emitting element, and the primary fluorescence emitted from one of the excited phosphors has a peak from one of the phosphors. Multiple excitation (also referred to as “cascade excitation”) that is absorbed and excited by the other phosphor having a longer wavelength occurs. Therefore, it is preferable that each phosphor has such a characteristic that such multiple excitation does not occur.

  Therefore, in the third phosphor according to the present embodiment, the intensity of the excitation spectrum at the peak wavelength of the emission spectrum of the light emitting element is Ia, and the excitation spectrum at the peak wavelength of the emission spectrum of the blue phosphor that is the second phosphor. If Ib is Ib, it is configured to satisfy Ib <Ia × 0.15.

  FIG. 8 is a diagram showing an excitation spectrum (line L1) of the phosphor 6 and an emission spectrum (line L2) of the blue phosphor that is the second phosphor. As shown in FIG. 8, when the intensity Ia of the excitation spectrum of the phosphor 6 at the peak wavelength 405 nm of the light emitting element is 100%, the phosphor 6 according to the present embodiment has a peak wavelength of the blue phosphor. The intensity Ib of the excitation spectrum of the phosphor 6 at a certain 456 nm is 11%, which satisfies the relational expression of Ib <Ia × 0.15. Thus, the phosphor 6 is less excited by the light emitted by the blue phosphor, which is the second phosphor, and can suppress color shift.

  For the same reason, the first phosphor according to the present embodiment has the excitation spectrum intensity Ic at the peak wavelength of the emission spectrum of the light emitting element, and the peak wavelength of the emission spectrum of the blue phosphor as the second phosphor. When the intensity of the excitation spectrum at Id is Id, it is configured to satisfy Id <Ic × 0.30.

  FIG. 9 is a diagram showing an excitation spectrum (line L3) of the phosphor 1 and an emission spectrum (line L2) of the blue phosphor that is the second phosphor. As shown in FIG. 9, the phosphor 1 according to the present embodiment has a peak wavelength of the blue phosphor assuming that the intensity Ic of the excitation spectrum of the phosphor 1 at the peak wavelength of 405 nm of the light emitting element is 100%. The intensity Id of the excitation spectrum of the phosphor 1 at a certain 456 nm is 27%, which satisfies the relational expression of Ic <Id × 0.0.30. Thus, the phosphor 1 is less excited by the light emitted by the blue phosphor, which is the second phosphor, and can suppress color shift.

  Light emitting modules according to the following examples were manufactured by combining the above-described phosphors. The light emitting module according to each embodiment includes a light emitting element that emits ultraviolet light or short wavelength visible light, a first phosphor that emits visible light when excited by ultraviolet light or short wavelength visible light, and ultraviolet light or short light. Excited by wavelength visible light, excited by ultraviolet light or short wavelength visible light, a second phosphor (blue phosphor) emitting visible light complementary to the visible light emitted by the first phosphor, A third phosphor that emits visible light (green phosphor) having a peak wavelength between the peak wavelength of visible light emitted by the first phosphor and the peak wavelength of visible light emitted by the second phosphor. And).

  Since the visible light emitted from the first phosphor and the visible light emitted from the second phosphor are complementary to each other, white light can be obtained. However, it is often difficult to obtain white light having high color rendering properties only by mixing two colors of light that are complementary to each other. Therefore, in the white light emitting module according to the present embodiment, in order to increase the intensity of the wavelength corresponding to green in the emission spectrum, the green phosphor is added in addition to the two colors of the yellow phosphor and the blue phosphor. .

Example 1
The light emitting module according to Example 1 is configured to emit light having a color temperature of 4300K (white). Specifically, a phosphor 1 having a peak emission wavelength near 570 nm as a yellow phosphor, a Ca apatite phosphor 2 as a blue phosphor, and a phosphor 6 as a green phosphor are used at a desired mixing ratio. Mix. This mixture is carefully mixed with an addition polymerization type silicone resin (KER-2600 (A / B) manufactured by Shin-Etsu Silicone Co., Ltd.) to a concentration of 10 to 15 vol% using a self-revolving stirring and de-mixing device, and then mixed with optical glass. A phosphor filter was produced by forming a film with a film thickness of about 150 μm and curing at 150 ° C. for 1 hour.

  This phosphor filter is installed on the exit surface of a surface-mounted LED that emits light at a wavelength of 400 nm, the LED is energized at 20 mA, and the emission characteristics of the emitted light are measured by an instrument system spectrum measuring device (CAS140B). evaluated. As a result, the weight ratio of phosphor 1 (yellow phosphor), phosphor 2 (blue phosphor), phosphor 6 (green phosphor) is 4.1 g: 1.5 g: 1.5 g, and the chromaticity is ( x, y) = (0.368, 0.371), which was within the color temperature range of 4300 K of ANSI (American National Standards Institute) standard. Further, the average color rendering index Ra = 80 of the light emitting module according to Example 1 is 4 points higher than Ra = 76 of the light emitting module according to Comparative Example 1 described later.

(Comparative Example 1)
The light emitting module according to Comparative Example 1 uses a phosphor 1 having a peak emission wavelength near 570 nm as a yellow phosphor, and a Ca apatite phosphor 2 as a blue phosphor, and these are mixed at a desired mixing ratio. Thereafter, a phosphor filter was produced by the same method as in Example 1, and the light emission characteristics of the light emitting module equipped with this phosphor filter were evaluated. As a result, the weight ratio of phosphor 1 (yellow phosphor) and phosphor 2 (blue phosphor) is 5.0 g: 1.5 g, and the chromaticity is (x, y) = (0.371, 0.385). ), Ra = 76.

  FIG. 10 is a diagram illustrating an emission spectrum of the light emitting module according to Example 1 and an emission spectrum of the light emitting module according to Comparative Example 1.

(Example 2)
The light emitting module according to Example 2 is configured to emit light having a color temperature of 5000 K (day white). Specifically, phosphor 1 is used as a yellow phosphor, phosphor 3 of Sr apatite is used as a blue phosphor, and phosphor 6 is used as a green phosphor, and these are mixed at a desired mixing ratio. Thereafter, a phosphor filter was produced by the same method as in Example 1, and the light emission characteristics of the light emitting module equipped with this phosphor filter were evaluated. As a result, the weight ratio of phosphor 1 (yellow phosphor), phosphor 3 (blue phosphor), phosphor 6 (green phosphor) is 3.0 g: 1.6 g: 1.8 g, and the chromaticity is ( x, y) = (0.344, 0.350), and it was within the range of the color temperature of 5000K of the ANSI standard. Further, the average color rendering index Ra of the light emitting module according to Example 2 was 81.4.

  FIG. 11 is a diagram showing an emission spectrum of the light emitting module according to Example 2.

(Example 3)
The light emitting module according to Example 3 is configured to emit light having a color temperature of 5500K (day white). Specifically, phosphor 1 is used as a yellow phosphor, CaSr apatite phosphor 4 is used as a blue phosphor, and phosphor 6 is used as a green phosphor, which are mixed at a desired mixing ratio. Thereafter, a phosphor filter was produced by the same method as in Example 1, and the light emission characteristics of the light emitting module equipped with this phosphor filter were evaluated. As a result, the weight ratio of phosphor 1 (yellow phosphor), phosphor 4 (blue phosphor), phosphor 6 (green phosphor) is 3.0 g: 2.0 g: 2.5 g, and the chromaticity is ( x, y) = (0.331, 0.342), and the color temperature was in the range of ANSI standard color temperature 5500K. Further, the average color rendering index Ra of the light emitting module according to Example 3 was 81.9.

  FIG. 12 is a diagram showing an emission spectrum of the light emitting module according to Example 3.

Example 4
The light emitting module according to Example 4 is configured to emit light having a color temperature of 6000 K (daylight color). Specifically, phosphor 1 is used as a yellow phosphor, phosphor 5 of a BAM phosphor is used as a blue phosphor, and phosphor 6 is used as a green phosphor, and these are mixed at a desired mixing ratio. Thereafter, a phosphor filter was produced by the same method as in Example 1, and the light emission characteristics of the light emitting module equipped with this phosphor filter were evaluated. As a result, the weight ratio of phosphor 1 (yellow phosphor), phosphor 5 (blue phosphor), phosphor 6 (green phosphor) is 2.0 g: 1.5 g: 2.0 g, and the chromaticity is ( x, y) = (0.322, 0.334), which was within the ANSI standard color temperature range of 6000K. Further, the average color rendering index Ra of the light emitting module according to Example 4 was 82.5.

  FIG. 13 is a diagram showing an emission spectrum of the light emitting module according to Example 4.

(Example 5)
The light emitting module according to Example 5 is configured to emit light having a color temperature of 6500K (daylight color). Specifically, phosphor 1 is used as a yellow phosphor, Ca apatite phosphor 2 is used as a blue phosphor, and phosphor 6 is used as a green phosphor, and these are mixed at a desired mixing ratio. Thereafter, a phosphor filter was produced by the same method as in Example 1, and the light emission characteristics of the light emitting module equipped with this phosphor filter were evaluated. As a result, the weight ratio of phosphor 1 (yellow phosphor), phosphor 5 (blue phosphor), phosphor 6 (green phosphor) was 2.0 g: 1.7 g: 2.1 g, and the chromaticity was ( x, y) = (0.313, 0.324), and the color temperature was within the range of ANSI standard color temperature 6500K. Further, the average color rendering index Ra of the light emitting module according to Example 5 was 83.5.

  FIG. 14 is a diagram showing an emission spectrum of the light emitting module according to Example 5.

  As shown in Examples 1 to 5, by using a green phosphor that is an oxide in addition to a yellow phosphor and a blue phosphor that are excited by a 400 nm InGaN / GaN-based semiconductor light-emitting device, three colors are mixed. In the light emitting module that realizes white, the average color rendering index Ra is improved to 80 or more in each white region as compared with the light emitting module using only the yellow phosphor and the blue phosphor.

  In the above, this invention was demonstrated based on embodiment and each Example. It is to be understood by those skilled in the art that this embodiment and each example are illustrative, and that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are also within the scope of the present invention. It is understood.

  The emission spectrum of the light-emitting element is not particularly limited as long as it emits at least ultraviolet rays or short-wavelength visible light. However, from the viewpoint of the emission efficiency of the light-emitting module, the peak wavelength of the emission spectrum is 350 nm to 420 nm. It is preferable to be included in the range.

  Moreover, as a specific example of a light emitting element, various light sources, such as semiconductor light emitting elements, such as LED and LD, a light source for obtaining light emission from a vacuum discharge or thermoluminescence, an electron beam excitation light emitting element, can be used, for example. More preferably, by using a semiconductor light emitting element as the light emitting element, a light emitting module having a small size, power saving, and long life can be obtained. As a suitable example of such a semiconductor light emitting device, an InGaN-based LED or LD having good light emission characteristics in a wavelength region near 400 nm can be given.

  The light emitting module of the present invention can be used for various lamps such as lighting lamps, displays, vehicular lamps, traffic lights and the like. In particular, application to general lighting fixtures that require color rendering properties can be expected.

  10 light emitting modules, 12 substrates, 14, 16 electrodes, 18 semiconductor light emitting elements, 20 mounting members, 22 wires, 24 phosphor filters.

Claims (6)

A light emitting element emitting ultraviolet light or short wavelength visible light;
A first phosphor that emits visible light when excited by the ultraviolet or short wavelength visible light;
A second phosphor that emits visible light that is excited by the ultraviolet light or short-wavelength visible light and has a complementary color relationship with visible light emitted by the first phosphor;
Visible light having a peak wavelength between the peak wavelength of visible light that is excited by the ultraviolet light or short-wavelength visible light and emitted from the first phosphor and the peak wavelength of visible light that is emitted from the second phosphor. A third phosphor that emits light,
The third phosphor has the intensity of the excitation spectrum at the peak wavelength of the emission spectrum of the light emitting element as Ia, and the intensity of the excitation spectrum at the peak wavelength of the emission spectrum of the first phosphor or the second phosphor. A light emitting module satisfying Ib <Ia × 0.15 when Ib is satisfied. The third phosphor is represented by the general formula Cs ₂ Sr _1-x P ₂ O ₇ : Eu ²⁺ _x (where x is in the range of 0 <x ≦ 0.3). The light-emitting module according to claim 1.   The light emitting module according to claim 1 or 2, wherein the third phosphor has a peak wavelength of an emission spectrum in a wavelength range of 500 to 580 nm. The first phosphor has a general formula of M ¹ O ₂ .aM ² O.bM ³ X ₂ : M ⁴ _c
(Where ^{M 1} is at least one element of Si, Ge, Ti, at least one element selected from the group consisting of Zr and Sn, ^{M 2} is selected from the group consisting of Mg, Ca, Sr, Ba and Zn , M ³ is at least one element selected from the group consisting of Mg, Ca, Sr, Ba and Zn, X is at least one halogen element, M ⁴ is Eu ²⁺ selected from the group consisting of rare earth elements and Mn. It represents at least one element that is essential, a is in the range of 0.1 ≦ a ≦ 1.3, and b is in the range of 0.1 ≦ b ≦ 0.25. Item 4. The light emitting module according to any one of Items 1 to 3.   When the intensity of the excitation spectrum at the peak wavelength of the emission spectrum of the light emitting element is Ic and the intensity of the excitation spectrum at the peak wavelength of the emission spectrum of the second phosphor is Id, the first phosphor has Id <Ic The light emitting module according to claim 1, wherein × 0.30 is satisfied.   The light emitting module according to claim 1, wherein the light emitting element emits ultraviolet light or short wavelength visible light having a peak wavelength in a wavelength range of 350 to 420 nm.

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