JP2003249688A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device capable of obtaining a different emitting color in accordance with an angle observed by an observer. <P>SOLUTION: The light emitting device 10 is provided with a light emitting diode (LED) chip 1, two lead frames 3, 4 and a disc-like phosphor 16. The lead frames 3, 4 consist of a metal such as copper alloy. Top of the lead frame 3 is formed like an L shape. A cup is formed on the top of the lead frame 3, the LED chip 1 is mounted in the cup, and the disc-like phosphor 16 is arranged with an interval from the LED chip 1. The LED chip 1, a wire 2, the phosphor 16, and the tops of the lead frames 3, 4 excluding the rear end parts of the lead frames 3, 4 are covered with resin mold 5. <P>COPYRIGHT: (C)2003,JPO

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 using a light emitting element and a phosphor.

[0002]

2. Description of the Related Art Light emitting diodes (hereinafter referred to as LEDs)
Is used in various fields as various light sources, red,
LEDs that emit light of green, blue, etc. have been developed.

In recent years, for example, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent No. 242513
An LED capable of emitting white light by combining a chip with a phosphor has also been proposed. FIG. 5 is a sectional view of a conventional light emitting device using an LED chip and a phosphor.

The light emitting device 50 includes an LED chip 51 and two lead frames 3 and 4. The lead frame 3 is formed in an L shape, and the lead frame 3
Has a concave shape. The LED chip 51 is mounted on the tip of the lead frame 3, and the upper electrode of the LED chip 51 is electrically connected to the lead frames 3 and 4 by the wire 2 such as gold. Further, the entire LED chip 51 is covered with the yellow phosphor-containing resin 56. The LED chip 51, the wire 2 and the lead frame 3, except for the rear end portions of the two lead frames 3 and 4.
The tip of 4 is covered with a resin mold 5.

In the light emitting device 50, when a current is applied to the LED chip 51 by applying a voltage between the two lead frames 3 and 4, blue light is emitted from the upper surface of the LED chip 51.

When blue light is generated by the LED chip 51, the yellow phosphor-containing resin 56 is excited by the blue light. As a result, yellow fluorescent light is generated from the yellow phosphor-containing resin 56. Then, the yellow phosphor mixed resin 56
The blue light that is not absorbed by and is transmitted by the yellow phosphor mixed with the yellow fluorescent material-containing resin 56 is converted into white light and emitted to the outside through the resin mold 5.

[0007]

However, the conventional light emitting device using the LED emits monochromatic light such as red light, green light, blue light, and white light, and therefore, when viewed from multiple directions, only monochromatic light is emitted. Invisible.

Therefore, when the light emitting device is used for decorative lighting, it is possible to obtain only monotonous light, which is insufficient from the viewpoint of decorativeness.

It is an object of the present invention to provide a light emitting device which can obtain different emission colors depending on the viewing angle of an observer.

[0010]

Means for Solving the Problems and Effects of the Invention In a light emitting device according to the present invention, a light emitting element for generating light and a phosphor excited by the light generated by the light emitting element are integrally formed, The phosphor is arranged such that a part of the light generated by the light emitting element enters the phosphor and the other light exits without entering the phosphor.

In the light emitting device according to the present invention, light is generated by the light emitting element, part of the light generated by the light emitting element is incident on the phosphor, and other light is incident on the phosphor. It is emitted without. Part of the light that has entered the phosphor is absorbed by the phosphor, and the remaining light passes through the phosphor. The phosphor is excited by the absorbed light to generate fluorescence. The fluorescence generated by the phosphor is combined with the light that has passed through the phosphor, and the combined light is emitted. On the other hand, the light that does not enter the phosphor is emitted as it is.

Therefore, when the light emitting device is viewed from the direction connecting the light emitting element and the phosphor, only the above-mentioned combined light emitted from the phosphor can be visually recognized. On the other hand, when the light emitting device is viewed from a direction other than the direction connecting the light emitting element and the phosphor, both the light generated by the light emitting element and the combined light emitted from the phosphor can be visually recognized.

As described above, since the light emission visually recognized varies depending on the direction in which the light emitting device is viewed, decorative light emission can be obtained and the directional characteristics of the emission color can be obtained.

The light emitting element and the phosphor may be covered with a translucent material, and the phosphor and the light emitting element may be arranged with a space. Thereby, the phosphor is easily integrated with the light emitting element by the translucent material. In this case, a part of the light generated by the light emitting element enters the phosphor through the translucent material, and the other light exits through the translucent material without entering the phosphor.

The light emitting element may be a semiconductor light emitting element, and the translucent material may be a molded body made of resin. In this case, it is possible to realize a compact light emitting device that can obtain a decorative effect and can obtain the directional characteristics of the emission color. In addition, since the light-transmitting material that covers the light-emitting element is a molded body made of resin, it is easy to manufacture.

The phosphor may be divided into parts made of a plurality of fluorescent materials that emit fluorescence of different colors depending on the light generated by the light emitting element. In this case, it is possible to visually recognize different emission colors depending on the viewing direction of the phosphor,
Further, decorative light emission can be obtained and a plurality of directional characteristics can be obtained.

The phosphor may be formed in a disc shape. In this case, a part of the light generated by the light emitting element is incident on the disc-shaped phosphor, and the other light is emitted from the outer peripheral portion of the disc-shaped phosphor.

The disc-shaped phosphor may be arranged perpendicularly to the normal line to the upper surface of the light emitting element. Alternatively, the disk-shaped phosphor may be arranged so as to be inclined with respect to the normal line of the upper surface of the light emitting element.

The light emitting element may be a light emitting diode. In this case, since the light emitting diode is small and emits divergent light, a compact light emitting device capable of producing decorative light from a wide angle range is realized.

The light emitting diode may be formed of a nitride semiconductor. As a result, light in the violet to blue wavelength region can be efficiently generated, and the phosphor can be efficiently excited by the violet to blue wavelength region light.

Since the light emitting element emits visible light, decorative light emission and light emission having directivity can be visually recognized by human eyes.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.

(First Embodiment) FIG. 1 is a sectional view showing the structure of a light emitting device according to the first embodiment.

The light emitting device 10 includes an LED (light emitting diode) chip 1, two lead frames 3 and 4, and a disk-shaped phosphor 16. The lead frames 3 and 4 are made of metal such as copper alloy. The leading end of the lead frame 3 is L-shaped. A cup is formed at the tip of the lead frame 3, and the LED chip 1 is mounted in the cup. One electrode of the LED chip 1 is electrically connected to the lead frame 3 by the wire 2, and the other electrode of the LED chip 1 is electrically connected to the lead frame 4 by the wire 2.

Further, a disk-shaped phosphor 16 is arranged at a distance from the LED chip 1, and the LED chip 1, the wire 2, the phosphor 16 and the leads are provided except for the rear end portions of the two lead frames 3 and 4. The tips of the frames 3 and 4 are covered with a resin mold 5.

The LED chip 1 emits visible light. In the present embodiment, the LED chip 1 is formed of a III-V group nitride semiconductor and has an InGaN light emitting layer.
The LED chip 1 emits blue light having a peak wavelength of 460 nm. Here, the nitride-based semiconductor is a nitride semiconductor containing at least one of gallium, indium, and aluminum.

The phosphor 16 is excited by the light generated from the LED chip 1 to generate fluorescence. In the present embodiment, the phosphor 16 is excited by the blue light generated by the LED chip 1 to generate yellow light. The composition of the phosphor 16 is (Y, Gd) ₃ Al ₅ O ₁₂ : Ce, for example, and the particle size is about 9 μm.

The phosphor 16 is used for the LED in the resin mold 5.
It is provided so as to be perpendicular to the normal line of the upper surface of the chip 1. Further, the phosphor 16 is provided in the middle portion of the resin mold 5 so as not to completely block the blue light generated by the LED chip 1.

The resin mold 5 is formed in a bell shape from a resin that transmits visible light. This resin mold 5 is formed in two steps. That is, after the LED chip 1, the wire 2, and the tips of the lead frames 3 and 4 are molded with resin in the first step, the phosphor 16 is molded in the second step.

In the light emitting device 10, when a current flows through the LED chip 1 by applying a voltage between the two lead frames 3 and 4, blue light is emitted from the upper surface of the LED chip 1. A part of the blue light Bu1 emitted from the LED chip 1 is incident on the phosphor 16.

Part of the blue light Bu1 incident on the phosphor 16 is absorbed by the phosphor 16 and the rest is transmitted through the phosphor 16. The phosphor 16 is excited by the absorbed blue light,
Emits yellow light. The yellow light generated by the phosphor 16 is combined with the blue light transmitted through the phosphor 16. As a result, the white light W1 is emitted from the phosphor 16. In this way, the phosphor 16 wavelength-converts the blue light generated by the LED chip 1 into white light. The white light W1 emitted by the phosphor 16 passes through the resin mold 5 and is emitted to the outside.

On the other hand, the remaining blue light Bu2 of the blue light emitted by the LED chip 1 is the LED chip 1
And the phosphor 16 are transmitted through the resin mold 5 and emitted to the outside.

As described above, the light emitting device 10 according to the present embodiment emits white light and blue light.

Next, as shown in FIG.
The color of the emitted light when viewed from the two directions A, B, and C will be described. In the following description, the normal direction of the upper surface of the LED chip 1 is the optical axis of the light emitting device 10. Direction A is light emitting device 1
The direction B is inclined to one side with respect to the optical axis of 0, the direction B is the direction of the optical axis of the light emitting device 10, and the direction C is inclined to the other side with respect to the optical axis of the light emitting device 10. Direction.

When an observer looks at the light emitting device 10 from the directions A and C, the white light W emitted by the phosphor 16 is emitted.
1 and the blue light Bu2 directly generated from the LED chip 1 can be visually recognized. On the other hand, when the observer looks at the light emitting device 10 from the direction B, only the white light W1 emitted by the phosphor 16 can be visually recognized.

Further, when the observer looks at the light emitting device 10 from the side, the LED chip 1 is not provided through the phosphor 16.
The blue light Bu2 directly emitted from is dominantly visible.

As described above, the light emitting device 10 of the present embodiment
In, the light of different colors can be visually recognized depending on the viewing direction of the light emitting device 10. Therefore, the light emitting device 10
When used for decorative lighting, decorativeness is improved. Further, it is possible to obtain a luminescent color having directivity.

When the distance between the LED chip 1 and the phosphor 16 is too small, most of the light generated by the LED chip 1 is incident on the phosphor 16 and the light is emitted between the LED chip 1 and the phosphor 16. The emitted blue light Bu2 is reduced. In this case, the observer can see the blue light Bu2 only in a very limited range. On the other hand, when the distance between the LED chip 1 and the phosphor 16 is too large, the visible range of the blue light Bu2 is widened, but the intensity of the blue light Bu1 that excites the phosphor 16 is reduced.
The white light W1 emitted from the light source becomes weaker. As a result, device characteristics deteriorate. Therefore, the interval between the LED chip 1 and the phosphor 16 is set so that the blue light Bu1 can be visually recognized and the white light W1 having a sufficient intensity can be visually recognized.

Further, when the area of the phosphor 16 is small in the plane direction, the range of the white light W1 emitted from the phosphor 16 is narrowed, and the ratio of the white light W1 is small in the visible range of the observer. Become. On the other hand, when the area of the phosphor 16 is large in the plane direction, the white light W1 emitted from the phosphor 16 is emitted.
Of the white light W1 within the visible range of the observer
The ratio of In this way, by adjusting the size of the area of the phosphor 16, it is possible to adjust the range in which the white light W1 is visible.

(Second Embodiment) FIG. 2 is a sectional view showing the structure of a light emitting device according to the second embodiment.

The structure of the light emitting device 20 according to the second embodiment has two types of phosphors 2 instead of the phosphor 16 of FIG.
It is the same as the first embodiment except that points 6 and 27 are provided.

Each of the phosphors 26, 27 has a semi-disc shape, and the phosphors 26, 27 are integrated into a disc shape by combining them.

The phosphors 26 and 27 are excited by the light generated from the LED chip 1 to generate fluorescence. In the present embodiment, the phosphor 26 is excited by the blue light generated by the LED chip 1 to generate yellow light. The composition of the phosphor 26 is, for example, (Y, Gd) ₃ Al ₅ O ₁₂ : Ce, and the particle size is about 9 μm. Further, the phosphor 27 is LE
The green light is generated by being excited by the blue light generated by the D chip 1. The composition of the phosphor 27 is, for example, Y ₃ Al.
₅ O ₁₂ : Ce, and the particle size is about 5 μm.

The integrated phosphors 26 and 27 are provided in the resin mold 5 so as to be perpendicular to the normal line to the upper surface of the LED chip 1. In addition, the phosphors 26, 27
Is provided in the middle part of the resin mold 5 so as not to completely block the blue light generated by the LED chip 1.

In the light emitting device 20, when a current flows through the LED chip 1 by applying a voltage between the two lead frames 3 and 4, blue light is emitted from the upper surface of the LED chip 1. A part of the blue light Bu1 emitted from the LED chip 1 is incident on the phosphors 26 and 27.

Part of the blue light Bu1 incident on the phosphor 26 is absorbed by the phosphor 26, and the rest is transmitted through the phosphor 26. The phosphor 26 is excited by the absorbed blue light,
Emits yellow light. The yellow light generated by the phosphor 26 is combined with the blue light transmitted through the phosphor 26. As a result, the white light W1 is emitted from the phosphor 26. In this way, the phosphor 26 wavelength-converts the blue light generated by the LED chip 1 into white light. The white light W1 emitted by the phosphor 26 passes through the resin mold 5 and is emitted to the outside.

On the other hand, the blue light Bu3 incident on the phosphor 27 is emitted.
Part of this is absorbed by the phosphor 27, and the rest is absorbed by the phosphor 27.
Through. The phosphor 27 is excited by the absorbed blue light to generate green light. The green light generated by the phosphor 27 is combined with the blue light transmitted through the phosphor 27.
As a result, the phosphor 27 emits white-green light G1. In this way, the phosphor 27 wavelength-converts the blue light generated by the LED chip 1 into white-green light. The white-green light G1 emitted by the phosphor 27 is the resin mold 5
And is emitted to the outside.

The remaining blue light Bu2 of the blue light emitted by the LED chip 1 is emitted from the LED chip 1 and the phosphors 26, 27 through the resin mold 5 to the outside.

As described above, the light emitting device 20 according to the present embodiment emits white light, white green light and blue light.

Next, as shown in FIG.
The color of the emitted light when viewed from the two directions A, B, and C will be described. In the following description, the normal direction of the upper surface of the LED chip 1 is the optical axis of the light emitting device 20. Direction A is light emitting device 2
The direction B is inclined to one side with respect to the optical axis of 0, the direction B is the direction of the optical axis of the light emitting device 20, and the direction C is inclined to the other side with respect to the optical axis of the light emitting device 20. Direction.

When the observer looks at the light emitting device 20 from the direction A, the LED chip 1 is not passed through the phosphors 26 and 27.
It is possible to visually recognize the blue light Bu2 emitted directly from, the white-green light G1 emitted by the phosphor 27, and the white light W1 emitted by the phosphor 26.

When the observer looks at the light emitting device 20 from the direction B, the white light W1 emitted by the phosphor 26 and the phosphor 2 are emitted.
The white-green light G1 emitted by 7 can be visually recognized.

When the observer looks at the light emitting device 20 from the direction C, the LED chip 1 is not passed through the phosphors 26 and 27.
It is possible to visually recognize the blue light Bu2 directly emitted from, the white light W1 emitted by the phosphor 26, and the white green light G1 emitted by the phosphor 27.

Here, when the observer looks at the light emitting device 20 from the side, only the blue light Bu2 directly emitted from the LED chip 1 can be dominantly visually recognized without passing through the phosphors 26 and 27.

As described above, the light emitting device 20 of the present embodiment
In, the light of different colors can be visually recognized depending on the viewing direction of the light emitting device 20. Therefore, the light emitting device 20
When used for decorative lighting, decorativeness is improved. Further, it is possible to obtain a luminescent color having directivity.

In the present embodiment, as in the first embodiment, the phosphor 26 integrated with the LED chip 1,
It is possible to change the visible range of various luminescent colors and the directivity of various luminescent colors by adjusting the distance between the fluorescent substance 26 and 27 or the size of the phosphors 26, 27 in the planar direction.

(Third Embodiment) FIG. 3 is a sectional view showing the structure of a light emitting device according to the third embodiment.

The structure of the light emitting device 30 according to the third embodiment is the same as that of the light emitting device 10 according to the first embodiment except the arrangement of the phosphor 16.

The phosphor 16 is used for the LED in the resin mold 5.
It is provided in a state of being inclined with respect to the normal line of the upper surface of the chip 1. That is, the phosphor 16 in the resin mold 5 is inclined so that the upper surface faces the direction A side and the lower surface faces the direction C side. Further, the phosphor 16 is provided in the middle portion of the resin mold 5 so as not to completely block the blue light generated by the LED chip 1.

In the light emitting device 30, when a current flows through the LED chip 1 by applying a voltage between the two lead frames 3 and 4, blue light is emitted from the upper surface of the LED chip 1. A part of the blue light Bu1 emitted from the LED chip 1 is incident on the phosphor 16.

As with the first embodiment, the LED chip 1
When a part of the blue light Bu1 emitted from the blue light Bu1 is incident on the phosphor 16, the phosphor 16 becomes
The wavelength of blue light generated by the chip 1 is converted into white light. In addition, the remaining blue light Bu2 of the blue light emitted by the LED chip 1 passes through the resin mold 5 from between the LED chip 1 and the phosphor 16 and is emitted to the outside.

As described above, white light and blue light are emitted from the light emitting device 30 according to the present embodiment.

Next, as shown in FIG.
The color of the emitted light when viewed from the two directions A, B, and C will be described. In the following description, the direction normal to the upper surface of the LED chip 1 is the optical axis of the light emitting device 30. Direction A is light emitting device 3
The direction B is inclined to one side with respect to the optical axis 0, the direction B is the direction of the optical axis of the light emitting device 30, and the direction C is inclined to the other side with respect to the optical axis of the light emitting device 20. Direction.

When the observer looks at the light emitting device 30 from the direction A, the blue light Bu2 directly emitted from the LED chip 1 and the white light W1 emitted by the phosphor 16 are not passed through the phosphor 16. Can be seen. In this case, since the phosphor 16 is inclined toward the direction A side, the white light W1 is visually recognized relatively stronger than the blue light Bu2.

When the observer looks at the light emitting device 30 from the direction B, the white light W1 emitted by the phosphor 16 can be visually recognized.

When the observer looks at the light emitting device 30 from the direction C, the blue light Bu2 directly emitted from the LED chip 1 and the white light W1 emitted by the phosphor 16 are not passed through the phosphor 16. Can be seen. In this case, since the phosphor 16 is inclined toward the direction A side, the white light W1 is visually recognized relatively weaker than the blue light Bu2.

As described above, the light emitting device 30 of the present embodiment
In, the light of different colors can be visually recognized depending on the viewing direction of the light emitting device 30. Therefore, the light emitting device 30
When used for decorative lighting, decorativeness is improved. Further, it is possible to obtain a luminescent color having directivity.

In this embodiment, similarly to the first embodiment, various emission colors can be obtained by adjusting the distance between the LED chip 1 and the phosphor 16 or the size of the phosphor 16 in the plane direction. It is possible to change the visible range and the directivity of various emission colors.

(Other Embodiments) In the first to third embodiments, LED chips are used as light emitting elements.
As the light emitting element, another light emitting element such as an organic electroluminescence element may be used.

(Application Example) FIG. 4 is a diagram showing an application example of the light emitting device according to the first embodiment.

Here, the light emitting device 10 according to the first embodiment is used for the purpose of allowing the observer to easily recognize the relative angle with respect to the target surface 47. The application method will be described below.

For example, for the target portion of the target surface 47,
It is assumed that the optical axis of the light emitting device 10 according to the embodiment is installed vertically. When the observer views the light emitting device 10 from the direction B which is the optical axis direction of the light emitting device 10, only the white light W1 is visually recognized. When an observer views the light emitting device 10 from the direction A or the direction C which is an oblique direction with respect to the optical axis of the light emitting device 10, the blue light Bu2 is visually recognized in addition to the white light W1.

Thus, the observer can recognize that the observation direction substantially coincides with the normal direction of the target surface 47 when only the white light W1 is visually recognized.
In addition to 1, when blue light Bu2 is visually recognized, it can be recognized that the observation direction does not match the normal direction of the target surface 47.

As in the application example shown above, according to the light emitting device of the present invention, not only the decorativeness is improved when it is used for decorative illumination, but also the directivity of various emission colors is utilized to obtain the target surface. The relative angle with can be recognized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a structure of a light emitting device according to a first embodiment.

FIG. 2 is a sectional view showing a structure of a light emitting device according to a second embodiment.

FIG. 3 is a sectional view showing a structure of a light emitting device according to a third embodiment.

FIG. 4 is a diagram showing an application example of the light emitting device according to the first embodiment.

FIG. 5 is a cross-sectional view of a conventional light emitting device using an LED chip and a phosphor.

[Explanation of symbols]

1 LED chip 2 wires 3,4 lead frame 5 resin mold 10, 20, 30 Light emitting device 16,26,27 Phosphor 47 Target surface A, B, C direction Bu1, Bu2, Bu3 blue light G1 white green light W1 white light

Claims (6)

[Claims] 1. A light-emitting element that emits light and a phosphor that is excited by the light generated by the light-emitting element are integrally configured, and a part of the light generated by the light-emitting element is A light-emitting device, wherein the phosphor is arranged so that it enters the phosphor and emits other light without entering the phosphor. 2. The light emitting device according to claim 1, wherein the light emitting element and the phosphor are covered with a translucent material, and the phosphor and the light emitting element are arranged with a gap. 3. The light emitting device is a semiconductor light emitting device,
3. The light emitting device according to claim 1, wherein the translucent material is a mold body made of resin. 4. The phosphor according to claim 1, wherein the phosphor is divided into a portion made of a plurality of fluorescent materials that emit fluorescence of different colors depending on the light generated by the light emitting element. The light-emitting device according to. 5. The light emitting device according to claim 1, wherein the light emitting element is a light emitting diode. 6. The light emitting device according to claim 1, wherein the light emitting diode is formed of a nitride semiconductor.