JP2002222996A - Led device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain white light not containing a yellow contour by a method wherein an LED which emits blue light is coated with a fluorescent material. SOLUTION: An LED 12 is arranged in the recess 18a of one lead frame 18 of the LED device (LED lamp) 10, and the other lead frame 16 and the LED 12 are connected by a bonding wire 20. The circumference of a part which is lower than a light emitting layer in the recess 19a of the LED 12 is sealed by using a transparent resin or a diffusion resin 22, and only a face which is higher than the light emitting layer is coated with the fluorescent material. Consequently, a distance at which light from the LED 12 passes a phosphor layer 14 is made nearly identical irrespective of a route, and the generation of the yellow contour is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED device for obtaining uniform white light.

[0002]

2. Description of the Related Art As an LED (light-emitting element) that emits blue light, for example, one using indium gallium nitride is known. White light is obtained by applying a fluorescent material to this blue-emitting LED. This is commonly done. FIG.
Shows an LED lamp 1 showing an example thereof, in which an LED 12 is arranged in a concave portion (parabola) 18a of a lead frame 18, and its upper portion and its periphery are, for example, YAG / Gd:
It is covered with a phosphor layer 14 made of a transparent epoxy resin containing Ce phosphor particles, and is connected to a lead frame 16 by a bonding wire 20. Although not shown for simplicity, the whole is sealed with, for example, epoxy resin. The LED 12 receives power supply from each lead frame and emits blue light, and obtains white light by mixing the light and yellow fluorescent light from the fluorescent material.

[0003]

SUMMARY OF THE INVENTION However, LEDs
The light emitted from the LED light source 12 is emitted directly through the fluorescent material layer 14, or is emitted from the reflection surface 18 b of the concave portion 18 a before being emitted to the outside.
The distance (thickness) of the fluorescent material layer through which the light emitted from the LED 12 passes is not uniform, and the fluorescent material is applied to the upper part and the entire periphery of the LED, so that the applied amount is large, and the applied fluorescent light is large. Because the thickness of the material layer is not always uniform, the blue light emitted from the LED is strongly affected by the fluorescent material layer due to these factors, and a yellow contour may be generated in the mixed white light. As a solution therefor, for example, as shown in FIG. 3, a transparent spacer S is deposited on and around the LED, and a fluorescent material is applied thereon to a substantially uniform thickness to form the LED 12 and the fluorescent material layer 14. There has been known a semiconductor device which separates an image and thereby suppresses the occurrence of the contour such as the yellow color (for example, Japanese Patent Application Laid-Open No. 2000-72000).
No. 7723). However, this semiconductor device has L
Since the transparent spacer S is deposited on and around the ED 12, the light emitted from the LED 12 is refracted by the transparent spacer S before entering the phosphor layer 14, that is, the spacer S is not provided. As compared with the case, the refraction is performed once more, so that there is a problem that light extraction efficiency is deteriorated. Therefore, an object of the present invention is to provide an LED device that can solve these problems.

[0004]

According to a first aspect of the present invention, a lower portion of a light emitting layer of an LED bonded to a substrate electrode is sealed with a transparent resin or a diffusion resin to seal the LED.
And a fluorescent material layer is formed by applying a fluorescent material only on the light emitting layer.

According to a second aspect of the present invention, an LED is disposed in a concave portion of one lead frame, and the other lead frame is connected to the LED by a bonding wire. The LED is characterized in that it is sealed with a transparent resin or a diffusion resin, and a fluorescent material layer is formed by applying a fluorescent material only above the light emitting layer.
It is a lamp.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. In the figure, the same parts as those of the conventional device are denoted by the same reference numerals. FIG. 1 shows an LED according to the present invention.
FIG. 3 is a cross-sectional view of the lamp 10, in which an LED 12 is disposed in a concave portion (parabola) 18 a of a first lead frame 18, and an upper surface electrode thereof is connected to a second lead frame 16 by a bonding wire 20. The periphery of the LED 12 at the portion below the light emitting layer is sealed with a transparent resin or a diffusion resin 22, and the fluorescent material 14 is applied on the upper surface of the LED 12 above the light emitting layer. The LED 12 emits blue light by receiving power supply from each lead frame as in the related art, and the light is mixed with the yellow fluorescent light excited by the fluorescent material to become white light. Here, the LED lamp 10
The blue light going upward from the light emitting layer is directly led out through the fluorescent material layer 14, and the light going below the light emitting layer passes through the transparent resin or the diffusion resin 22. Therefore,
Light directed to the lower side of the light emitting layer is reflected by the reflection surface 18 of the concave portion 18.
Since the fluorescent material is not affected at all by the light reflected by b, the thickness of the fluorescent material layer 14 which passes when the reflected light goes out of the device is different from the case of the light directly going out of the LED 12 to the outside. Absent. Therefore, according to the present invention, the LED
No matter which path the light emitted from the LED 12 exits the device, there is no great difference in the distance that the light from the LED 12 passes through the fluorescent material layer 14 as in the related art. Therefore, there is no possibility that a yellow outline is generated in the white light. Further, in the conventional device, it is necessary to fill the entirety of the concave portion (parabola) 18 with the fluorescent material, but in the LED device according to the present invention, this is not necessary, so that the amount of the fluorescent material can be reduced.

[0007]

According to the present invention, a transparent or diffusion resin is sealed below the light emitting layer of the LED disposed in the frame recess, and the fluorescent material is applied only above the light emitting layer of the LED. Accordingly, the amount of the fluorescent material applied can be reduced, and a yellow contour does not occur in white light as in the related art.

[Brief description of the drawings]

FIG. 1 is a sectional view of an LED device (LED lamp) of the present invention.

FIG. 2 is a cross-sectional view of a conventional LED device (LED lamp).

FIG. 3 is a sectional view of a main part of another conventional LED device (LED lamp).

[Explanation of symbols]

10 ... Semiconductor device (LED lamp), 12 ... L
ED, 14 ... fluorescent material, 16, 18 ... first and second
Lead frame, 18a: concave portion (parabola) of lead frame, 20: bonding wire, 22 ·
..Transparent resin or diffusion resin,

Claims (2)

[Claims] 1. A method in which the periphery of a lower portion of a light emitting layer of an LED bonded to a substrate electrode is sealed with a transparent resin or a diffusion resin, and a fluorescent material is applied only to a portion above the light emitting layer of the LED to obtain a fluorescent light. LED characterized by forming a material layer
apparatus. 2. An LED is provided in a recess of one lead frame.
Is arranged, the other lead frame and the LED are connected by a bonding wire, and the lower portion of the LED is sealed with a transparent resin or a diffusion resin around the lower part of the light emitting layer, and the upper part of the LED is sealed with the diffusion resin. An LED lamp characterized in that a fluorescent material layer is formed by applying a fluorescent material only to the fluorescent material layer.