JP2000347601A - Light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently take out light output such as brightness without receiving loss such as scatter or absorption when converted light passes through a wavelength conversion part by taking out converted light generated in the wavelength conversion part so as not to transmit the wavelength conversion part. SOLUTION: In this LED lamp 10, UV light outgoing from a UV-LED is made incident on a fluorescent material layer 18, wavelength-converted by the fluorescent material layer 18 to emit visible light of long wavelength, and RGB-mixed in the fluorescent material to take out while light. Out of the while light, the white light generated in the fluorescent material layer 18 nearby the UV-LED transmits through the UV-LED without passing through the fluorescent material layer, and is released from a plate 12 side to be a light take-out part. Further the other while light, after the major part is reflected by a reflection plate 19, is released from the plate 12 side with transmitting through the UV-LED or without transmitting through it. Hereby when the while light passes through the fluorescent material layer, it does not incur loss such as scatter or absorption.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device,
More specifically, the present invention relates to a phosphor light emitting device in which a semiconductor light emitting element and a phosphor are combined.

[0002]

2. Description of the Related Art In recent years, a display device using a light emitting device combining a semiconductor light emitting element and a phosphor as a light source has been developed in place of an existing display device such as a cathode ray tube or a liquid crystal display panel.

A light emitting device combining a phosphor and a semiconductor light emitting element includes, for example, a blue light emitting diode (LED) made of a GaN-based semiconductor and a YAG emitting yellow light.
A phosphor light emitting device in which a phosphor is combined is known. In this phosphor light emitting device, the center wavelength 4
White light (converted light) is extracted by mixing the color of blue light around 50 nm with the light emitted from the phosphor that has received this light (emission having a spectral distribution having a peak near the wavelength of 560 nm). In this type of conventional phosphor light emitting device, a phosphor is applied around a semiconductor light emitting element, and the semiconductor light emitting element is embedded in a phosphor layer.

[0004]

By the way, inside the phosphor, not only emission due to wavelength conversion, but also scattering and absorption of incident light and fluorescence emission occur. For this reason, when the semiconductor light emitting element is embedded in the phosphor layer and the visible light is extracted through the phosphor layer as in the conventional case, the converted light is scattered and absorbed by the phosphor layer. There has been a problem that the light output is reduced.

An object of the present invention is to provide a light emitting device capable of extracting light output efficiently.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a light source unit having a semiconductor light emitting element as a light source, and receiving light emitted from the light source unit to generate converted light having different wavelengths. And a wavelength conversion unit for extracting the converted light generated by the wavelength conversion unit without passing through the wavelength conversion unit.

According to a second aspect of the present invention, in the first aspect, the converted light generated by the wavelength converter is transmitted through the semiconductor light emitting element and extracted.

According to a third aspect of the present invention, in the first or second aspect, an incident direction of light from the light source unit to the wavelength conversion unit is opposite to an emission direction of the converted light from the wavelength conversion unit. And

A fourth aspect of the present invention is characterized in that, in any of the first to third aspects, the semiconductor light emitting device is made of a semiconductor selected from the group consisting of GaN, SiC, BN and ZnSe. .

[0010] The invention of claim 5 is characterized in that, in any of claims 1 to 4, the wavelength conversion section comprises a phosphor layer.

According to the above configuration, since the converted light generated by the wavelength converter is extracted without passing through the wavelength converter, the converted light is susceptible to loss such as scattering and absorption when passing through the wavelength converter. And light output such as luminance can be efficiently extracted.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a light emitting device according to the present invention is applied to an LED lamp will be described below with reference to the drawings.

[First Embodiment] FIGS. 1A to 1E are schematic sectional views showing a process of manufacturing an LED lamp according to a first embodiment.

In the first embodiment, a GaN-based LED (hereinafter, referred to as UV) emitting UV light is used as a semiconductor light emitting element serving as a light source unit.
-LED). In addition, as a phosphor layer serving as a wavelength conversion portion, phosphor materials of R, G, and B colors are formed at a color temperature of 650.
It is compounded according to the white color of 0K and mixed with an inorganic adhesive.

First, as shown in FIG. 1A, a UV-LED 1 is placed at a predetermined position on a plate 12 transparent to visible light.
1 is arranged and fixed with the transparent adhesive 13. Plate 1
Reference numeral 2 is made of a base material mixed with a UV absorbing material, and absorbs ultraviolet light and transmits only visible light. UV- on plate 12
As shown in FIG. 1B, a case portion 15 having a substantially concave cross section in which a metal layer 14 such as Au serving as an electrode is formed on the upper surface is provided around the LED 11. And FIG.
As shown in (c), the metal layer 14 and the UV-LED 11
Metal electrode 17 with p electrode 16a and n electrode 16b
Connect with. Next, as shown in FIG. 1D, the inside of the case portion 15 is filled with an inorganic adhesive (or resin) mixed with a phosphor material without gaps to form the phosphor layer 18. Subsequently, as shown in FIG. 1E, the reflection plate 19 is fitted on the light emitting surface side of the UV-LED 11 and fixed. Although not shown, the light extraction portion may be subjected to a process such as forming a lens for condensing light.

The LED lamp 10 is completed through the manufacturing steps shown in FIGS. 1 (a) to 1 (e). In actual manufacturing, a plurality of LEs are placed in a frame called a frame.
Mass production can be achieved by simultaneously forming the D lamps and individually taking them out of this frame.

An LED lamp having a shape as shown in FIG.
Generally, surface mount type (SMD: Surface Mount)
ted Device) LED. By arranging such LED lamps in an array, it can be used as a light source for a display device.

The surface of the plate 12 may be coated with a UV scattering material or a UV reflecting material. Further, in addition to a plate transparent to visible light, a plate having a light guiding property may be used.

The LED lamp 1 manufactured as described above
In the case of 0, the UV light emitted from the UV-LED 11 enters the phosphor layer 18 and is converted in wavelength by the phosphor layer 18 to emit long-wavelength visible light. Is taken out. Of this white light, UV-L
The white light generated in the phosphor layer 18 close to the ED 11 does not pass through the phosphor layer 18 and passes through the UV-LE, as shown in FIG.
The light passes through D11 and is emitted from the plate 12 side serving as a light extraction unit. Further, most of the other white light is emitted from the plate 12 side without being transmitted or transmitted through the UV-LED 11 after most of the white light is reflected by the reflection plate 19.

As described above, since the white light is extracted from the back surface of the UV-LED 11 without the phosphor layer 18, the white light does not suffer loss such as scattering and absorption when passing through the phosphor layer, and the luminance is reduced. And the like can be efficiently extracted. In particular, when the reflection plate 19 is provided,
The light output can be further increased.

[Second Embodiment] FIGS. 3A and 3B are schematic cross-sectional views showing a process of manufacturing an LED lamp according to a second embodiment. In the second embodiment, a UV-LED having the same structure as that of the first embodiment is used.

As shown in FIG. 3A, the UV-LED 2
A metal layer 23 serving as an electrode is formed on a submount 22 on which the substrate 1 is fixed, and a phosphor layer 24 is formed of a resin mixed with a phosphor material. A part of the phosphor layer 24 electrically divides the metal layer 23, and the phosphor layer 2
A cutout portion 25 is provided in a portion corresponding to the positions of the p and n electrodes of the UV-LED 21 of No. 4. And UV
-The solder 101 is mounted on the p and n electrodes of the LED 21, aligned with the notch 25 in a planar manner, and flip-chip mounted on the submount 22. As a result, the p- and n-electrodes of the UV-LED 21 are connected to the electrically divided metal layers 23, respectively. The p- and n-electrodes of the UV-LED 21 and the metal layer 23
May be joined by thermocompression bonding.

Next, as shown in FIG.
The submount 22 on which the ED 21 is mounted is mounted on a metal (F
e) and the mount 26 formed on the frame 26
a) is mounted in a with a transparent adhesive (not shown). A reflector 27 is formed on the inner surface of the mount 26a. After that, the metal layer 23 and the frame 26 are connected by a metal wire 28. Here, when one of the metal layers 23 is formed up to the back surface of the submount 22, the back surface of the submount 22 and the mounting portion 26a of the frame 26 are electrically mounted by mounting with a conductive adhesive. Connection, and the other side of the metal layer 23 is connected to the frame 26 by a wire.

Next, a phosphor-containing solvent is injected into the mount 26a of the frame 26 to the same height as the surface of the UV-LED 21 opposite to the submount 22. next,
The phosphor layer 29 is formed by evaporating or curing the solvent at a high temperature. And, as shown in FIG.
The entire lamp-mounted portion of the UV-LED 21 is molded into a lens shape with a resin 30 containing a UV absorbing material to complete the LED lamp 20.

The LED lamp 2 manufactured as described above
In the case of 0, the UV light emitted from the UV-LED 21 enters the phosphor layer 29, is converted in wavelength by the phosphor layer 29, emits long-wavelength visible light, and is mixed with RGB inside the phosphor to produce white light. Is taken out. Of this white light, UV-L
As shown in FIG. 5, the white light generated in the phosphor layer 29 close to the ED 21 does not pass through the phosphor layer 29, and does not pass through the UV-LE.
D21 is transmitted to the outside. Further, most of the other white light is reflected by
The light is emitted outside without transmitting or transmitting through the LED 21.

Also in this case, since the white light is extracted from the back surface without the phosphor layer 29, there is no loss such as scattering and absorption when the white light passes through the phosphor layer.
Light output such as luminance can be efficiently extracted. In particular, when the reflection plate 27 is provided, the light output can be further increased.

A coating having a high reflectance to visible light is applied between the surface of the submount 22 and the phosphor layer. However, when the submount material is transparent to visible light, it becomes unnecessary.

Before molding with the resin 30 containing the UV absorbing material, the UV-light including the phosphor layer 29 in the reflection plate 27 is used.
The surface of the LED 21 may be coated with a UV scattering material or a UV reflecting material. In addition, on the back side (substrate side) of the UV-LED 21, the film thickness is λλ (λ is the UV emission wavelength).
By coating the UV reflective film set to, together with metal thin film, dielectric thin film, dielectric multilayer film, etc.,
Further, the bonding with the phosphor layer 29 can be enhanced. The same effect can be achieved, for example, by coating the outermost surface with a UV reflecting film or a UV reflecting material before molding the resin 30 into a lens shape. However,
It is desirable that the UV reflection film or the UV reflection material used at this time is transparent to visible light.

[Third Embodiment] FIGS. 5A and 5B are schematic structural views showing a process of manufacturing an LED lamp according to a third embodiment. The basic configuration of the LED lamp according to the third embodiment is almost the same as that of the second embodiment.
3 and 4 are denoted by the same reference numerals.

The UV-LED 21 of the fourth embodiment is flip-chip mounted on a transparent submount 32. The structure of the mount portion is substantially the same as that of FIG. 3A, and a metal layer (not shown) serving as an electrode is formed on the surface of the submount in the state of being electrically divided, as in the second embodiment.

On the other hand, the mount 26a of the frame 26
Has a phosphor layer 31 formed on its inner surface with a uniform thickness. The phosphor layer 31 may be formed by a method using a binder as in a normal phosphor coating method, or may be mixed with a coating material (adhesive) from which a heat-resistant transparent film can be obtained and injected. The inner diameter may be formed by inserting a shape mold and molding the inner diameter.

The mounting portion 26a constructed as described above
The submount 32 provided with the UV-LED 21 is mounted on the phosphor layer 31 with the transparent adhesive 102. Thereafter, a metal layer (not shown) of the submount 32 and the frame 2
6 is connected by a metal wire 28. Next, frame 2
The resin 33 is injected into the mount part 26a of No. 6 and cured (heat cured). Further, as shown in FIG.
The LED lamp 35 is completed by molding into a lens shape with a resin 34 containing a V-absorbing material.

The LED lamp 3 manufactured as described above
Also for 5, the white light emitted from the submount 32 side is extracted from the back surface without the phosphor layer 31, so that the white light does not suffer loss such as scattering and absorption when passing through the phosphor layer, Light output such as luminance can be efficiently extracted.

In particular, in the configuration of the third embodiment, U
The phosphor layer 31 formed in the direction in which the V light is emitted has the same thickness, and the path length when the UV light from the UV-LED 21 moves in the phosphor layer 31 is substantially the same. More uniform light emission can be obtained as compared with the second configuration.

The resin 34 used for molding may contain a UV reflecting material or a UV scattering material instead of the UV absorbing material.

On the back side (substrate side) of the UV-LED 21, a solvent such as a UV absorbing material or a UV scattering material is applied, or a dielectric multilayer film having a thickness set to 1 / 2λ is used. By coating a UV reflective film made of, it is possible to easily and easily achieve high efficiency.
Further, by processing the back surface side of the UV-LED 21 into a lens shape (dome shape), it is possible to further increase the efficiency.

Fourth Embodiment FIGS. 6A to 6C are schematic cross-sectional views showing a process of manufacturing an LED lamp according to a fourth embodiment. Also in this embodiment, a UV-LED is used as a semiconductor light emitting element serving as a light source unit.

As shown in FIG. 6A, a metal layer 43 serving as an electrode is formed on a transparent or light guide plate 42. Next, as shown in FIG. 6B, the UV-LED 4 is placed at a predetermined position on the plate 42 via the transparent adhesive 44.
Fix 1 Thereafter, the metal layer 43 of the plate 42 and U
The p-electrode 45a and the n-electrode 45b of the V-LED 41 are connected by metal wires 46, respectively.

Next, as shown in FIG. 6C, the plate 42 and the box-shaped case 47 are joined. A phosphor layer 4 having a truncated conical cross section is provided at the center of the case 47.
8 are formed. Outside the phosphor layer 48, a reflection plate 49 is further formed. On the other hand, the outer periphery of the case 47 is provided with metal layers 50a, 5a for obtaining electrical connection.
0b is formed. These metal layers 50a, 50b
In the final product form in which the plate 42 and the case 47 are joined, this is for obtaining an electrical connection between the side surface or the back surface of the case 47 and a mounting board (not shown).
The metal layers 50a and 50b are electrically divided so as to correspond to the p and n electrodes of the UV-LED 41, and are formed independently of each other.

The metal layers 50a and 50b of the case 47 and the metal layer 43 on the plate 42 are joined by sealing by compression, thermocompression or welding. Case 4
The interior of 7 may be vacuum, filled with an inert gas such as N ₂ or Ar, or filled with a transparent resin.

The LED lamp 5 manufactured as described above
7, light emitted from the UV-LED 41 is converted into visible light by the phosphor layer 48 inside the case 47 and reflected by the reflection plate 49, and then transmitted through the UV-LED 41, as shown in FIG. It is released from the side of the plate 42 serving as a take-out part. At this time, if the light guide plate 42 is used, the entire plate surface emits light. This LED lamp 5
Even at 0, the white light emitted from the plate 42 side is extracted from the back surface without the phosphor layer 48, so that the white light does not suffer loss such as scattering and absorption when passing through the phosphor layer, and And the like can be efficiently extracted.

Particularly, in the fourth embodiment, UV-L
Without flip-chip mounting the ED 41, the same function as in the case of flip-chip mounting can be obtained. Therefore, it becomes easier to produce an LED lamp than in the case of flip-chip mounting.

By evacuating the case 47 or filling the case 47 with an inert gas, the UV-LED 41 and the phosphor layer 48 can be brought into non-contact. As a result, U
The heat generated by the V-LED 41 is not directly transmitted to the phosphor layer 48, and a decrease in conversion efficiency due to the temperature characteristics of the phosphor can be prevented. Furthermore, in the case of high-temperature light emission, particularly in the case of multicolor light emission, an LED lamp with a small change in color tone can be obtained.

Also, the LED lamp 50 of Embodiment 4 can be mass-produced by actually forming a plurality of LED lamps simultaneously in a frame called a frame and taking out the LED lamps individually from the frame. .

Since the LED lamp 50 is completed by joining the plate 42 side and the case 47 side, the structure of the plate 42 side is changed to the phosphor layer 4 to be joined.
Regardless of the eight colors, they can be shared. further,
Since the case 47 side and the plate 42 side can be manufactured on different lines, for example, the case 47 side can be stocked for each color of the phosphor layer 48.

In the first to fourth embodiments, an example in which a UV-emitting GaN-based LED is used as a semiconductor light-emitting element has been described.
Similar effects can be obtained even when ED or the like is used.

In the light emitting device according to the present invention, the semiconductor light emitting element used for the light source section is a GaN-based LE.
In addition to D, an LED made of a semiconductor selected from any group of SiC, BN, and ZnSe can be used.

When a UV-emitting semiconductor LED is used, for example, the following can be used as the center wavelength of the UV emission.

(1) When the active layer is GaN, the center wavelength is 365 nm. (2) When the active layer is InGaN, the center wavelength is 365 to 380 nm depending on the In composition. (3) When the AlGaN / InAlGaN is, the center wavelength is 340 to 380 nm (4) In the case of BGaN, the center wavelength is 300 to 365 nm. Further, as the R, G, and B phosphors used in the wavelength converter, for example, the following can be used.

Blue (Sr, Ca, Ba, Eu) (su
bscript: 10) (PO (subscript:
4)) (subscript: 6) · Cl (subsc
Ript: 2) Green 3 (Ba, Mg, Eu, Mn) 0.8 Al (su
bscript: 2) 0 (subscript: 3) Red La (subscript: 2) 0 (subsc
Rip: 2) S: Eu, Sm Further, as a UV absorber used for a light extraction portion such as a plate or a submount, for example, the following can be used.

(1) TiO ₂ (2) 2- (2-hydroxy-5-methylp)
(henyl) -2Hbenzotriazole (3) 2- (3-tert-butyl-2-hydr)
oxy-5-methylphenyl) -5-chl
oro-2H-benzotriazole (4) 2- (2-hydroxy-5-tert-oc
(typhenyl) -2H-benzotriazole (5) ethyl12-cyano-3, 3-diphe
nylacrylate

[0051]

As described above, in the light emitting device according to the present invention, the converted light generated by the wavelength converter is extracted without transmitting through the wavelength converter.
When the converted light passes through the wavelength conversion section, loss such as scattering and absorption is not caused, and light output such as luminance can be efficiently extracted.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a manufacturing process of an LED lamp according to a first embodiment.

FIG. 2 is a schematic sectional view showing a light emitting state of the LED lamp according to the first embodiment.

FIG. 3 is a schematic sectional view showing a manufacturing process of the LED lamp according to the second embodiment.

FIG. 4 is a schematic sectional view showing a completed state of the LED lamp according to the second embodiment.

FIG. 5 is a schematic configuration diagram showing a manufacturing process of the LED lamp according to the third embodiment.

FIG. 6 is a schematic sectional view showing a manufacturing process of the LED lamp according to the fourth embodiment.

FIG. 7 is a schematic sectional view showing a light emitting state of an LED lamp according to a fourth embodiment.

[Explanation of symbols]

 10, 20, 35, 50 LED lamps 11, 21, 41 UV-LEDs 12, 42 Plates 14, 23, 43, 50 Metal layers 18, 24, 31, 48 Phosphor layers 19, 27, 49 Reflectors 22, 32 Submount 26 Frame 47 Case

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koichi Nitta 1-Front Term, Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa F-term (reference) 5C094 AA02 BA26 CA24 ED20 FB14 5F041 AA03 AA11 CA33 CA34 CA40 CA43 CA46 DA18 DA20 DA26 DA46 DA57 EE23

Claims (5)

[Claims] A light source unit having a semiconductor light emitting element as a light source;
A wavelength converter that receives light emitted from the light source unit and generates converted light having different wavelengths, wherein the converted light generated by the wavelength converter is extracted without passing through the wavelength converter. Light emitting device. 2. The light emitting device according to claim 1, wherein the converted light generated by said wavelength converter passes through said semiconductor light emitting element and is extracted. 3. The light emitting device according to claim 1, wherein an incident direction of light from the light source unit to the wavelength conversion unit and an emission direction of the converted light from the wavelength conversion unit are opposite to each other. 4. The semiconductor light-emitting device is a GaN-based, SiC
2. The semiconductor device according to claim 1, comprising a semiconductor selected from the group consisting of BN, BN, and ZnSe.
4. The light emitting device according to any one of claims 3 to 3. 5. The light emitting device according to claim 1, wherein said wavelength conversion section is made of a phosphor layer.