JP2011096739A - Light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device which suppresses secondary absorption at a wavelength conversion layer, and emits light with less color unevenness. <P>SOLUTION: The light-emitting device includes: a first LED chip (a first light-emitting element) 11 and a second LED chip (a second light-emitting element) 21, both mounted on a mounting substrate 4; a first wavelength conversion layer 12 arranged on the first LED chip 11, absorbing blue light, and emitting green fluorescent light; a first translucent member 5 for covering the first LED chip 11 and the first wavelength conversion layer 12; a second wavelength conversion layer 22 arranged on the second LED chip 21, absorbing blue light, and emitting red fluorescent light at a longer wavelength than that of the green fluorescent light from the first wavelength conversion layer 12; and a second translucent member 6 for covering the second LED chip 21 and second wavelength conversion layer 22. The first translucent member 5 has a larger refractive index than the second translucent member 6, and is in contact with the second translucent member 6. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light emitting device and a light emitting device using a wavelength conversion layer that converts the wavelength of light from the light emitting device.

  In recent years, a light-emitting element composed of a semiconductor light-emitting element such as an LED chip mounted on a mounting substrate, and a light that covers the light-emitting element, absorbs at least part of the light from the light-emitting element, and converts the wavelength to become a complementary color. For example, a light-emitting device that emits white light that is a mixture of blue light from a light-emitting element and yellow light from a wavelength conversion layer has been developed. ing. This type of light-emitting device has been used for lighting fixtures as the light output of light-emitting elements is increased.

  By the way, the light emitting device emits blue light, a phosphor emitting green light (green phosphor), and red light, for example, in order to make radiating white light closer to natural light such as sunlight. In some cases, the color rendering property of white light is enhanced by using a wavelength conversion layer combined with a phosphor (red phosphor).

  In a light emitting device including such a wavelength conversion layer containing a plurality of types of phosphors, a phosphor having a long wavelength of the main emission wavelength (for example, a red phosphor) is a phosphor having a shorter wavelength than the main emission wavelength ( For example, part of the light converted by the green phosphor is absorbed (hereinafter referred to as secondary absorption) and wavelength-converted. Therefore, the light emitting device cannot sufficiently increase the light emission efficiency due to the overlap of the loss accompanying the wavelength conversion in the phosphor.

  Therefore, in order to suppress the above-described secondary absorption between a plurality of types of phosphors, a light emitting device having a structure separated into a wavelength conversion layer containing a green phosphor and a wavelength conversion layer containing a red phosphor It is considered. For example, as shown in FIG. 6, the first LED chip 11 and the second LED chip 21 respectively mounted on one surface of the mounting substrate 4 and the entire first LED chip 11 are covered and the first LED chip 11 is covered. The first wavelength conversion layer 12 ′ containing a phosphor that absorbs light from the LED chip 11 and emits fluorescence, and the second LED chip 21 are covered so that the light from the second LED chip 21 is reflected. A second wavelength conversion layer 22 ′ containing a phosphor that absorbs and emits fluorescence having a longer wavelength than the fluorescence from the first wavelength conversion layer 12 ′, the first LED chip 11, and the first wavelength conversion A transparent member 15 covering the layer 12 ′, the second LED chip 21 and the second wavelength conversion layer 22 ′, and the first wavelength conversion layer 12 ′ and the second wavelength conversion layer 22 ′. A light-emitting device 10 ′ having a reflective film 14 formed at the boundary is proposed. Are (e.g., see Patent Document 1). On the mounting substrate 4, there is a reflective layer 13 that reflects light from the first LED chip 11, the first wavelength conversion layer 12 ′, the second LED chip 21, and the second wavelength conversion layer 22 ′. Is formed.

  In the light emitting device 10 ′ shown in FIG. 6, the light emitted from the first LED chip 11 is applied to the first wavelength conversion layer 12 ′ and emitted from the phosphor of the first wavelength conversion layer 12 ′. Light is emitted isotropically in all directions. However, in the light emitting device 10 ′ shown in FIG. 6, the reflective film 14 is formed at the boundary between the first wavelength conversion layer 12 ′ and the second wavelength conversion layer 22 ′, so that the first wavelength The light radiated from the conversion layer 12 ′ is reflected by the reflection film 14, and can be emitted efficiently without being secondarily absorbed by the second wavelength conversion layer 22 ′. .

JP 2009-117825 A

  However, in the light emitting device 10 ′ configured as shown in FIG. 6, the reflective film 14 reflects the light emitted from the first wavelength conversion layer 12 ′ and the light emitted from the second wavelength conversion layer 22 ′, respectively. Radiate to the outside. Therefore, when it is difficult for the light emitting device 10 ′ to sufficiently mix the light from the first wavelength conversion layer 12 ′ emitted from the light emitting device 10 ′ and the light from the second wavelength conversion layer 22 ′. There is.

  In particular, in the light emitting device 10 ′ used for illumination purposes, as the distance between the light emitting device 10 ′ and the irradiation surface irradiated with the mixed color light from the light emitting device 10 ′ increases, the color unevenness of the irradiated mixed color light is uneven. In the present situation where more uniform light is demanded, the above-described configuration of the light emitting device 10 ′ is not sufficient, and further improvement is demanded.

  The present invention has been made in view of the above-described reasons, and an object thereof is to provide a light-emitting device capable of suppressing secondary absorption in the wavelength conversion layer and obtaining light with less color unevenness. It is in.

  According to a first aspect of the present invention, there is provided a first light emitting element and a second light emitting element that are respectively mounted on one surface of a mounting substrate, and the light from the first light emitting element that is provided on the first light emitting element. A first wavelength conversion layer that absorbs at least a portion and emits fluorescence; a first translucent member that covers the first light emitting element and the first wavelength conversion layer; and the second light emitting element. A second wavelength conversion layer that absorbs at least part of light from the second light emitting element and emits fluorescence having a longer wavelength than the fluorescence from the first wavelength conversion layer; and A second light-transmitting member that covers the light-emitting element and the second wavelength conversion layer, and the first light-transmitting member has a higher refractive index than the second light-transmitting member, And it is in contact with said 2nd translucent member, It is characterized by the above-mentioned.

  According to this invention, the first translucent member has a refractive index larger than that of the second translucent member and is in contact with the second translucent member. Part of the green light of the first wavelength conversion layer emitted by absorbing blue light emitted from the light emitting element is totally reflected by the second light transmissive member. Therefore, the light emitting device can suppress the green light from the first wavelength conversion layer from being incident on the second wavelength conversion layer and secondarily absorbed, thereby increasing the light emission efficiency. Further, the light from the first wavelength conversion layer is not completely reflected by the second light transmissive member. Furthermore, the light emitted from the second wavelength conversion layer can pass through the first translucent member. Therefore, the light emitting device can easily mix the light from the first and second wavelength conversion layers, and emits light with less color unevenness without causing a decrease in light emission efficiency. Can do.

  According to a second aspect of the present invention, in the first aspect of the present invention, the second translucent member is characterized in that a diffusing material is dispersed.

  According to this invention, since the diffusing material is dispersed in the second light transmissive member, the light from the second light emitting element and the second wavelength conversion layer is transmitted to the second light transmissive member. Since the light is distributed so that the light is emitted outward from the conductive member, color mixing with the light emitted from the first light emitting element and the first wavelength conversion layer is promoted. Therefore, the light emitting device can emit mixed color light with less color unevenness.

  According to the first aspect of the present invention, the first light transmissive member covering the first light emitting element and the first wavelength conversion layer, and the second light transmitting element covering the second light emitting element and the second wavelength conversion layer. The first translucent member has a refractive index larger than that of the second translucent member and is in contact with the second translucent member. There is a remarkable effect that it is possible to provide a light emitting device capable of suppressing the secondary absorption in the second wavelength conversion layer and emitting light with less color unevenness.

1 is a schematic cross-sectional view showing a light emitting device of Embodiment 1. FIG. The light emission from the wavelength conversion layer of a light-emitting device is shown, (a) is an explanatory view of a light-emitting device for comparison, (b) is an explanatory view of the light-emitting device of Embodiment 1, and (c) is an illustration of Embodiment 1. It is principle explanatory drawing in a light-emitting device. 6 is a schematic cross-sectional view showing another light emitting device of Embodiment 1. FIG. It is a schematic sectional drawing which shows another light-emitting device same as the above. 6 is a schematic cross-sectional view showing a light emitting device of Embodiment 2. FIG. It is a schematic sectional drawing which shows the conventional light-emitting device.

(Embodiment 1)
Hereinafter, the light emitting device of this embodiment will be described with reference to FIGS. 1 to 4. In FIG. 1 to FIG. 4, the same members are denoted by the same reference numerals and redundant description is omitted.

  The light emitting device 10 shown in FIG. 1 of the present embodiment includes a first LED chip 11 that is a first light emitting element that emits blue light mounted on one surface 4 a of the mounting substrate 4, and the first LED chip 11. And a first wavelength conversion layer 12 made of a translucent resin layer containing a green phosphor that absorbs part of the blue light from the first LED chip 11 and emits green fluorescence. Yes. The light emitting device 10 is provided on the second LED chip 21 and the second LED chip 21 that is a second light emitting element that emits blue light mounted on the one surface 4 a of the mounting substrate 4. A first light-transmitting resin layer containing a red phosphor that absorbs part of the blue light from the LED chip 21 and emits red fluorescence having a longer wavelength than the green fluorescence of the first wavelength conversion layer 12. And a second wavelength conversion layer 22. Here, the light emitting device 10 includes a first light-transmissive member 5 that covers the first LED chip 11 and the first wavelength conversion layer 12, a second LED chip 21, and a second wavelength conversion layer 22. The first translucent member 5 has a refractive index larger than that of the second translucent member 6 and the second translucent member 6. It touches.

  In the light emitting device 10, the first wavelength conversion layer 12 that emits green fluorescence on the first LED chip 11 and the first LED chip 11 is used as the short wavelength light emitting unit 1, and the second LED chip 21 and the second LED chip 21. The second wavelength conversion layer 22 that emits red fluorescence on the LED chip 21 is the long wavelength light emitting section 2.

  More specifically, the light emitting device 10 uses a mounting substrate 4 in which a pair of conductor patterns (not shown) plated with Au are formed on a rectangular flat alumina ceramic substrate. A plurality of Au bumps 3 are provided on each of the first and second LED chips 11 and 21 in the pair of conductor patterns of the mounting substrate 4. The first LED chip 11 and the second LED chip 21 mounted on the one surface 4a of the mounting substrate 4 are respectively an n-type gallium nitride compound semiconductor layer and a gallium nitride system containing In on the sapphire substrate. A light emitting layer made of a compound semiconductor and a p-type gallium nitride compound semiconductor layer are sequentially stacked. In the first and second LED chips 11 and 21, a part of the p-type gallium nitride compound semiconductor layer and the light emitting layer are removed, and the n-type gallium nitride compound semiconductor layer is partially exposed. An anode electrode and a cathode electrode that are electrically connected to the p-type and n-type gallium nitride compound semiconductor layers are provided on the same plane side. The first and second LED chips 11, 21 are arranged such that the anode electrode and the cathode electrode provided on the same plane side of the first and second LED chips 11, 21 are placed on a pair of conductor patterns on the mounting substrate 4. The Au bump 3 is flip-chip mounted so that power can be supplied.

  The first and second LED chips 11 and 21 mounted on the one surface 4a of the mounting substrate 4 respectively emit blue light having a peak wavelength in the range of 450 nm to 470 nm, for example, when energized. The outer shapes of the first and second LED chips 11 and 21 can be, for example, about 1 mm square and about 100 μm thick.

The first wavelength conversion layer 12 is a green phosphor capable of absorbing green light from the first LED chip 11 and emitting green light (for example, (SrBa) ₂ SiO ₄ activated with Eu) ) Is uniformly dispersed in a silicone resin serving as a binder, and the outer shape is approximately the same as the first LED chip 11 and is formed in a film shape having a thickness of approximately 100 μm. The short wavelength light emitting unit 1 is formed by adhering the first wavelength conversion layer 12 on the first LED chip 11 with an adhesive having translucency.

Similarly, the second wavelength conversion layer 22 binds a red phosphor capable of absorbing blue light from the second LED chip 21 and emitting red light (for example, CaAlSiN ₃ activated with Eu) as a binder. The outer shape is approximately 1 mm square, which is substantially the same as that of the second LED chip 21, and is formed in a film shape having a thickness of about 100 μm. The long wavelength light emitting unit 2 is formed by adhering the second wavelength conversion layer 22 on the second LED chip 21 with an adhesive having translucency.

  By the way, the phosphor is excited by energy from the excitation source (here, blue light from the first and second LED chips 11 and 21) and emits fluorescence isotropically in all directions. A part of the light emitted from the first wavelength conversion layer 12 of the light emitting device 10 is also directed to the second wavelength conversion layer 22 side. Therefore, for example, in the case of the light emitting device 10 ″ shown in FIG. 2A, the green light emitted from the first wavelength conversion layer 12 containing the green phosphor of the short wavelength light emitting unit 1 to the long wavelength light emitting unit 2 side. (Arrows in FIG. 2A) are secondarily absorbed by the second wavelength conversion layer 22 containing a red phosphor.

  2A is different from the first wavelength conversion layer 12 of the short wavelength light emitting unit 1 in the long wavelength light emitting unit 2 side. 2 (the arrow in FIG. 2B) is totally reflected by the second light transmissive member 6 and is emitted to the outside of the light emitting device 10. Therefore, the light emitting device of FIG. 10 reduces the amount of light emitted from the first wavelength conversion layer 12 and reaching the second wavelength conversion layer 22 as compared with the light emitting device 10 ″ of FIG. It is possible to suppress a decrease in luminous efficiency due to the secondary absorption.

  That is, as illustrated in FIG. 2C, the light emitting device 10 of the present embodiment emits light emitted from the first wavelength conversion layer 12 toward the long wavelength light emitting unit 2 (an arrow in FIG. 2C). A) is totally reflected on the surface of the second translucent member 6. More specifically, the light-emitting device 10 includes the above-described light (see the arrow A in FIG. 2C) and a tangent line on the surface of the second translucent member 6 that is irradiated with the light (see FIG. What is necessary is just to design so that the angle which makes | forms the perpendicular (refer the dashed-dotted line C in FIG.2 (c)) of the perpendicular (refer the broken line B in 2 (c)) becomes more than critical angle (theta).

  In FIG. 2A, a translucent member that covers the short wavelength light emitting unit 1 is omitted for the sake of explanation. Further, in FIGS. 2B and 2C, the first light having a refractive index larger than that of the second light transmissive member 6 is covered with the short wavelength light emitting unit 1 and is in contact with the second light transmissive member 6. The translucent member 5 is omitted.

  Hereinafter, each component used for the light-emitting device 10 of this embodiment is explained in full detail.

  The first and second light-emitting elements used in the light-emitting device 10 of Embodiment 1 can emit light when energized. The light emitted from the first and second light emitting elements can be, for example, blue light having a peak wavelength of 450 nm to 470 nm in visible light, but is not limited to blue light, and has other wavelengths. Ultraviolet light may be used to efficiently excite the light, the first wavelength conversion layer 12 and the second wavelength conversion layer 22. As the LED chips 11 and 21 as light emitting elements, for example, an n-type gallium nitride compound semiconductor layer, a multiple quantum well structure on a crystal growth substrate such as a sapphire substrate, a spinel substrate, a gallium nitride substrate, a zinc oxide substrate or a silicon carbide substrate. And a gallium nitride compound body layer containing indium and a p-type gallium nitride compound semiconductor layer, which are light emitting layers having a single quantum well structure, are sequentially stacked.

  Note that the LED chips 11 and 21 using the insulating substrate have anodes on the same plane side by exposing a part of the n-type gallium nitride compound semiconductor layer from the p-type gallium nitride semiconductor layer side. An electrode and a cathode electrode can be formed respectively. Moreover, what is necessary is just to form the anode electrode and the cathode electrode in the LED chip 11 and 21 using the electroconductive board | substrate on the both surfaces side of the thickness direction of the LED chip 11 and 21. FIG.

  The anode electrode and the cathode electrode provided on the LED chips 11 and 21 are materials that can obtain good ohmic characteristics with a laminated film of a Ni film and an Au film, a gallium nitride compound semiconductor layer such as an Al film and an ITO film, and the like. If there is, it is not limited.

  The LED chips 11 and 21 provided with the anode electrode and the cathode electrode on the same plane side can be flip-chip mounted on a pair of conductive patterns on the mounting substrate 4 using metal bumps such as Au bumps 3. When the LED chips 11 and 21 having the anode electrode and the cathode electrode formed on both sides in the thickness direction are used as the LED chips 11 and 21, on the mounting substrate 4 on which the LED chips 11 and 21 are mounted. One conductor pattern of the formed pair of conductor patterns and the anode electrode or the cathode electrode of the LED chips 11 and 21 are die-bonded via a conductive member (for example, AuSn or Ag paste). Connect them electrically. Further, the other cathode electrode or anode electrode on the light extraction surface side of the LED chips 11 and 21 may be electrically connected to the other conductor pattern via a wire (for example, a gold wire or an aluminum wire). Good.

  In the light emitting device 10 shown in FIG. 1 of the present embodiment, two first LED chips 11 and 11 on the peripheral portion of the one surface 4a on the mounting substrate 4 and the one surface 4a on the mounting substrate 4 are provided. Although one second LED chip 21 is mounted at the center, the number of LED chips 11 and 21 may be one or more. In this case, the LED chips 11 and 21 may be electrically connected in series, parallel, or series-parallel as appropriate. The first and second LED chips 11 and 21 may be of the same type, or a plurality of LED chips 11 and 21 that emit light having different emission wavelengths. In the case where the light emitting device 10 is disposed on the one surface 4a of the mounting substrate 4 so that the long wavelength light emitting unit 2 is surrounded by the plurality of short wavelength light emitting units 2, the effect of suppressing secondary absorption is particularly remarkable. appear.

  Next, the mounting substrate 4 used in the light emitting device 10 of the present embodiment can mount the first and second LED chips 11 and 21 as light emitting elements. Further, the mounting substrate 4 may constitute a current-carrying path for the LED chips 11 and 21 by using the pair of conductor patterns (for example, a conductor pattern plated with Au on the outermost surface) on the mounting substrate 4. . As the mounting substrate 4, a ceramic substrate using alumina, aluminum nitride, or the like, a metal base substrate using a metal material such as Fe, Cu, or Al, a glass epoxy resin substrate, or the like can be used. When an alumina ceramic substrate is used as the mounting substrate 4, it is easy to form a conductor pattern, has higher thermal conductivity than a glass epoxy resin substrate, etc., and efficiently generates heat generated by lighting the LED chips 11 and 21. The heat radiation of the light emitting device 10 can be enhanced by sufficiently dissipating heat. When the metal base substrate is used as the mounting substrate 4, an insulating layer may be appropriately formed on the metal base substrate so that the LED chips 11 and 21 are not electrically short-circuited.

  The light emitting device 10 of the present embodiment uses a rectangular flat plate-shaped mounting substrate 4, but radiates from the short wavelength light emitting unit 1 and the long wavelength light emitting unit 2 to the outer peripheral portion of the one surface 4 a of the mounting substrate 4. Side walls (not shown) may be provided in order to make the emitted light easily radiate to the outside. Since the side wall has a tapered portion that spreads outward from the one surface 4a of the mounting substrate 4, light can be easily extracted to the outside of the light emitting device 10, and a decrease in light emission efficiency of the light emitting device 10 can be suppressed. . In addition, as the mounting substrate 4 having the side wall, a lead frame having a cup may be used. When a lead frame including a cup is used as the mounting substrate 4, the light emitting device 10 may have the first LED chip 11 and the second LED chip 21 mounted on the inner bottom surface of the cup.

  In the light emitting device 10 of the present embodiment, a reflective layer that reflects light may be provided on the side wall. For example, when silver plating is formed on the side wall as a reflective layer, the silver plating is a reflection loss of about 2% in one reflection with respect to light emitted from the short wavelength light emitting unit 1 and the long wavelength light emitting unit 2. Can only occur. Needless to say, the reflective layer may be provided on the tapered portion.

Further, the light emitting device 10 may be provided with a reflecting portion (not shown) on the one surface 4 a of the mounting substrate 4, and such a reflecting portion has a length of light emitted from the short wavelength light emitting portion 1 and a long length. Specifically, it is capable of efficiently reflecting the light emitted from the wavelength light emitting unit 2, and specifically, a metal material such as Al, Al alloy, Ag, and Ag alloy, or an inorganic material that becomes a white pigment such as BaSO ₄ What is necessary is just to comprise using the glass material etc. which contain. In the light emitting device 10 of the present embodiment, the light emitting efficiency of the short wavelength light emitting unit 1 is increased by providing the reflecting unit, and secondary absorption in the second wavelength conversion layer 22 by the light reflected by the reflecting unit is also performed. It becomes possible to suppress. In addition, when the reflection part has conductivity, the light emitting device 10 includes the reflection part and the cathode so that the anode electrode and the cathode electrode of each of the first and second LED chips 11 and 21 are not short-circuited. An insulating layer (not shown) may be appropriately formed between the pair of conductor patterns.

  The mounting substrate 4 may be configured as an external electrode of the light emitting device 10 by extending a conductor pattern from the one surface 4 a of the mounting substrate 4 to the side surface and the back surface. Such external electrodes of the light emitting device 10 can be electrically connected to a wiring board (not shown) by a reflow process or the like.

  The first and second wavelength conversion layers 12 and 22 used in the present embodiment absorb at least a part of light emitted from the first and second LED chips 11 and 21 that are light emitting elements, respectively, and perform wavelength conversion. The fluorescent light having a peak on the longer wavelength side than the light from the first and second LED chips 11 and 21 is emitted.

  For example, the first wavelength conversion layer 12 absorbs a part of the light emitted from the first LED chip 11 and converts a phosphor that emits fluorescence having an emission peak on a longer wavelength side into a silicone resin or an acrylic resin. What is necessary is just to include and form in translucent materials, such as resin, an epoxy resin, and glass. The second wavelength conversion layer 22 contains a phosphor that absorbs part of the light emitted from the second LED chip 21 and emits fluorescence having an emission peak on the longer wavelength side. It emits light having a longer wavelength than the fluorescence of one wavelength conversion layer 12. Similarly to the first wavelength conversion layer 12, the second wavelength conversion layer 22 can also contain, for example, a phosphor in a translucent material such as a silicone resin, an acrylic resin, an epoxy resin, or glass. In order to change the light emitted from the light emitting device 10 into white light having high color rendering properties, the first and second LED chips 11 and 21 that emit blue light and the first and second wavelength conversion layers 12 and 22 In this combination, a green phosphor can be used as the phosphor for the first wavelength conversion layer 12, and a red phosphor can be used as the phosphor for the second wavelength conversion layer 22.

  The thicknesses of the first and second wavelength conversion layers 12 and 22 are the target color temperature of the light emitted from the light emitting device 10 and the blue light emitted from the first and second LED chips 11 and 21, respectively. For example, it can be formed to a thickness of about 100 μm, although it varies depending on the emission intensity and the phosphor content.

Examples of the phosphor used for the first and second wavelength conversion layers 12 and 22 include aluminum such as Y ₃ Al ₅ O ₁₂ activated by Ce and Tb ₃ Al ₅ O ₁₂ activated by Ce. In addition to nate-based phosphors, silicate-based phosphors such as Eu-activated Ba ₂ SiO ₄ and Eu-activated (SrBa) ₂ SiO ₄ , Eu-activated CaAlSiN ₃ , Eu nitrides such as CaSi ₇ N ₁₀ which is activated by in activated with _Sr 2 _Si 5 _N 8, _Ca were activated by Eu 2 _Si 5 _N 8, Eu in-activated the SrSi ₇ N ₁₀ and Eu It is also possible to employ a phosphor of the system. The phosphors used in the first and second wavelength conversion layers 12 and 22 are not limited to the green phosphor for the first wavelength conversion layer 12 and the red phosphor for the second wavelength conversion layer 22. Even when used as a yellow phosphor for the first wavelength conversion layer 12 and a red phosphor for the second wavelength conversion layer 22, white light can be obtained.

  In the light emitting device 10 of the present embodiment, the first LED chip 11 and the first wavelength conversion layer 12 are covered with the first light-transmissive member 5, and the second LED chip 21 and the second wavelength conversion are performed. The layer 22 is covered with the second translucent member 6. In the light emitting device 10, the refractive index of the first light transmissive member 5 is made larger than the refractive index of the second light transmissive member 6. The first translucent member 5 is in contact with the second translucent member 6, and preferably the first translucent member 5 covers the second translucent member 6.

  As a result, the light emitting device 10 fluoresces from the first wavelength conversion layer 12 on the first LED chip 11 mounted on the one surface 4a of the mounting substrate 4 as shown in FIG. (Refer to the arrow in the figure) can be prevented from being incident on the second light-transmissive member 6, and a decrease in light emission efficiency associated with secondary absorption in the second wavelength conversion layer 22 can be suppressed. At the same time, light with less color unevenness can be obtained.

  For example, in the light emitting device 10, among the green light emitted from the first wavelength conversion layer 12 formed on the first LED chip 11, a part of the green light is the long wavelength light emitting unit 2 on the mounting substrate 4. Head to the side. However, the light emitting device 10 covers the second wavelength conversion layer 22 with the second light transmissive member 6 having a relatively lower refractive index than the first light transmissive member 5. The ratio of light reflection due to the difference in refractive index at the interface between the translucent member 5 and the second translucent member 6 increases. Thereby, the light-emitting device 10 is suppressed from entering green light into the second wavelength conversion layer 22, suppresses secondary absorption by the second wavelength conversion layer 22, and further suppresses a decrease in light emission efficiency. Is possible.

  Such first and second translucent members 5 and 6 are suitable for covering the short-wavelength light-emitting portions 1 and 1 and the long-wavelength light-emitting portion 2, respectively, and protecting them from external forces. A light-transmitting material that is used and has a high light-transmitting property in the visible range can be suitably used. Specific materials for the first and second translucent members 5 and 6 include silicone resin, acrylic resin, epoxy resin, glass, and the like, and a material having a suitable refractive index according to the site to be used is appropriately used. Adopted for. For example, the epoxy resin can have a refractive index of 1.55 to 1.61, and the silicone resin can have a refractive index of 1.35 to 1.53.

  When a silicone resin is used as the first and second translucent members 5, 6, a phenyl silicone resin is used as the first translucent member 5, and a fluorine-based resin is used as the second translucent member 6. By using a silicone resin, the refractive index of the 1st translucent member 5 can be made higher than the refractive index of the 2nd translucent member 6. FIG.

  The first and second translucent members 5 and 6 are, for example, first formed as the second translucent member 6 after forming the short wavelength light emitting unit 1 and the long wavelength light emitting unit 2 on the mounting substrate 4 respectively. A fluorine-based silicone resin material is filled so as to surround the long-wavelength light emitting portion 2 and cured by heating. Next, a plurality of short wavelength light emitting portions 1, 1 and second on the mounting substrate 4 on which the second translucent member 6 is formed by using the phenyl silicone resin material to be the first translucent member 5. What is necessary is just to apply | coat so that the translucent member 6 may be coat | covered, and to heat-harden it.

  In addition, the refractive index is larger than the 2nd translucent member 6 in the interface which the 1st translucent member 5 and the 2nd translucent member 6 contact | connect, than the 1st translucent member 5 Alternatively, a third translucent member (not shown) having a low refractive index may be provided. By providing the third translucent member, the light from the first wavelength conversion layer 12 that was not reflected at the interface between the first translucent member 5 and the third translucent member, It is possible to reflect at the interface between the third translucent member and the second translucent member 6. Therefore, the light emitting device 10 further suppresses light from the first wavelength conversion layer 12 that travels from the first light transmissive member 5 to the second light transmissive member 6 as a whole, and suppresses a decrease in light emission efficiency. It becomes possible.

  In the light emitting device 10, when a plurality of short wavelength light emitting units 1 and long wavelength light emitting units 2 are arranged on one surface 4 a of the mounting substrate 4, the second translucent member 6 has individual long wavelengths. You may form each with respect to the light emission part 2, and you may provide the one 2nd translucent member 6 with respect to the some long wavelength light emission part 2. FIG. That is, as in the light emitting device 10 shown in FIG. 3, for example, the two long wavelength light emitting units 2 and 2 are individually covered with the two second light transmissive members 6 and 6, respectively. With the single translucent member 5, the two translucent members 6 and 6 and the two short wavelength light emitting units 1 and 1 can be covered.

  Accordingly, the light emitting device 10 shown in FIG. 3 takes into account the distance and output between each short wavelength light emitting unit 1, 1 and each long wavelength light emitting unit 2, 2 and refracts the translucent members 6, 6 separately. By changing the ratio and the shape of the interface between the first translucent member 5 and the second translucent members 6, 6, the secondary absorption in the second wavelength conversion layer is suppressed and the color mixing property is improved. It becomes possible.

  In addition, the light emitting device 10 illustrated in FIG. 4 includes, for example, two long wavelength light emitting units 2 and 2 covered with one second light transmissive member 6 and one first light transmissive member 5. The second translucent member 6 and the two short-wavelength light emitting portions 1 and 1 can be covered.

  Accordingly, the light-emitting device 10 shown in FIG. 4 can be manufactured with high productivity because the light-transmitting members 5 and 6 need only be formed once.

  Next, the manufacturing process of the light emitting device 10 of this embodiment will be described.

  The first LED chip 11 is flip-chip mounted on the one surface 4 a of the mounting substrate 4 using a plurality of Au bumps 3. Similarly, the second LED chip 21 is flip-chip mounted on the one surface 4 a of the mounting substrate 4 using a plurality of Au bumps 3. Prior to flip chip mounting, the first and second LED chips 11, 21 are each formed with a first wavelength conversion layer 12 on the first LED chip 11, and on the second LED chip 21. A second wavelength conversion layer 22 is formed. As a method for forming the first and second wavelength conversion layers 12 and 22, a film-like sheet (size: about 1 mm square, thickness of about 1 mm square) filled with a phosphor using a silicone resin as a translucent member as a binder. 100 μm) may be adhered to the sapphire substrate of the LED chips 11 and 21 with a translucent adhesive.

  Accordingly, the first LED chip 11 mounted on the one surface 4a of the mounting substrate 4 has the first wavelength conversion layer 12 containing the green phosphor, and the second LED chip 21 has the red phosphor. The contained second wavelength conversion layer 22 is loaded.

  The first and second wavelength conversion layers 12 and 22 are formed by mounting the first and second LED chips 11 and 21 on the mounting substrate 4, and then using the screen printing method. Each of the LED chips 11 and 21 can be formed by applying a translucent material containing a phosphor. The first and second wavelength conversion layers 12 and 22 are formed by mounting the first and second LED chips 11 and 21 on the mounting substrate 4 and then using the ink jet printing method. A translucent material containing a phosphor may be discharged onto the LED chips 11 and 21 and formed respectively.

  Subsequently, in the light emitting device 10 according to the present embodiment, the second LED chip 21 and the second wavelength conversion layer 22 are coated with the second translucent member 6 made of a fluorine-based silicone resin, covered, and heated. Harden. Thereafter, the first light-transmissive member 5 made of a phenyl-based silicone resin is coated on the first LED chip 11, the first wavelength conversion layer 12, and the second light-transmissive member 6, and then heated and cured. I am letting. Thereby, in the light emitting device 10, the refractive index of the first light transmissive member 5 is made larger than the refractive index of the second light transmissive member 6. The first translucent member 5 is in contact with and covers the second translucent member 6. The shape of the interface with the first and second translucent members 5 and 6 can be changed relatively easily by adjusting the viscosity of the translucent material when the second translucent member 6 is formed. can do.

(Embodiment 2)
This embodiment is different in that a diffusing material 7 is included in the second light transmissive member 6 of the first embodiment shown in FIG. 1 as shown in the light emitting device 10 of FIG. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted suitably.

  Hereinafter, the light emitting device 10 of the present embodiment will be described with reference to a schematic cross-sectional view shown in FIG.

  In the light emitting device 10 shown in FIG. 5 of the present embodiment, the first LED chip 11 that emits blue light uses a plurality of Au bumps 3 on a conductor pattern (not shown) on one surface 4 a of the mounting substrate 4. Flip chip mounting. Similarly, the second LED chip 21 that emits blue light is flip-chip mounted on a conductor pattern (not shown) on the one surface 4 a of the mounting substrate 4 using a plurality of Au bumps 3. On the first LED chip 11, a first wavelength conversion comprising a translucent resin layer containing a green phosphor that absorbs part of the blue light from the first LED chip 11 and emits green fluorescence. Layer 12 is formed. Similarly, on the second LED chip 11, a second light-transmitting resin layer containing a red phosphor that absorbs a part of blue light from the second LED chip 21 and emits red fluorescence is contained. The wavelength conversion layer 22 is formed. Thereby, in this light-emitting device 10, the 1st LED chip 11 and the 1st wavelength conversion layer 12 which emits the green fluorescence on the 1st LED chip 11 are used as the short wavelength light emission part 1, and the 2nd LED chip 21 And the 2nd wavelength conversion layer 22 which emits the red fluorescence on the 2nd LED chip 21 is comprised as the long wavelength light emission part 2. FIG.

  Further, in the light emitting device 10 of the present embodiment, the two short wavelength light emitting portions 1, 1 provided on the peripheral portion of the one surface 4 a of the mounting substrate 4 are covered with the first translucent member 5, and One long wavelength light emitting portion 2 provided at the center of one surface 4 a is covered with a second light transmissive member 6. In the light emitting device 10, the refractive index of the first light transmissive member 5 is larger than the refractive index of the second light transmissive member 6. The first translucent member 5 is in contact with the second translucent member 6, and preferably the first translucent member 5 covers the second translucent member 6.

  In the light emitting device 10 of the present embodiment, in particular, the light of the long wavelength light emitting unit 2 is emitted from the second light transmissive member 6 of the mounting substrate 4 by including the diffusing material 7 in the second light transmissive member 6. Is diffused and emitted to the outside. Accordingly, the light emitting device 10 illustrated in FIG. 5 further spreads the light distribution of the light emitted from the second light transmissive member 6 and emits light from the light emitting device 10 as compared with the light emitting device 10 that does not contain the diffusing material 7. It is possible to further promote the color mixing of the emitted light. In addition, a decrease in luminous efficiency can be reduced as compared with the light emitting device 10 in which both the first light transmissive member 5 and the second light transmissive member 6 contain the diffusing material 7.

  Examples of the material of the diffusing material 7 include inorganic materials such as aluminum oxide, silica, and titanium oxide, organic materials such as fluorine-based resins, and organic-inorganic hybrids in which organic components and inorganic components are combined at the molecular level and particle level. The average particle size may be appropriately selected from several μm to several tens of μm, for example.

  In addition, in order to form the 2nd translucent member 6 containing the diffusing material 7, the diffusing material 7 is dispersed and contained in advance in the translucent material of the second translucent member 6 before curing. The light-transmitting material in which the diffusing material 7 is dispersed may be coated on the surface 4a of the mounting substrate 4 on which the long-wavelength light emitting portion 2 is disposed and heat-cured.

4 mounting substrate 4a one surface 5 first light transmissive member 6 second light transmissive member 7 diffusing material 10 light emitting device 11 first LED chip (first light emitting element)
12 1st wavelength conversion layer 21 2nd LED chip (2nd light emitting element)
22 Second wavelength conversion layer

Claims (2)

  A first light-emitting element and a second light-emitting element respectively mounted on one surface of the mounting substrate; and at least part of light from the first light-emitting element that is provided on the first light-emitting element and absorbs fluorescence A first wavelength conversion layer that emits light, a first translucent member that covers the first light emitting element and the first wavelength conversion layer, and the second light emitting element provided on the second light emitting element. A second wavelength conversion layer that absorbs at least part of light from the light emitting element and emits fluorescence having a longer wavelength than the fluorescence from the first wavelength conversion layer; the second light emitting element; and the second light emitting element A second translucent member that covers the wavelength conversion layer, wherein the first translucent member has a refractive index greater than that of the second translucent member and the second translucent member. A light-emitting device in contact with the sexual member.   The light-emitting device according to claim 1, wherein the second light-transmissive member includes a diffusing material dispersed therein.

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