JP4886253B2 - Light emitting device - Google Patents

Description

  The present invention relates to a light emitting device used for irradiating light from a light emitting element to the outside.

Conventionally, as this type of light emitting device, there is a device that emits light having a wavelength different from that of the light emitted from the light emitting element by exciting the phosphor with the light emitted from the light emitting element. For example, the light-emitting device disclosed in Patent Document 1 is configured to include a resin portion in which a phosphor is dispersed in a resin in the direction of light emission from a semiconductor light-emitting element (light-emitting element). Thereby, it is possible to irradiate the outside with mixed color light of the light emitted from the semiconductor light emitting element and the light emitted from the phosphor.
JP 2003-46133 A (pages 4-7 and FIG. 1)

  However, in the conventional light emitting device, the resin portion must have a certain strength or more so as to withstand an impact. For this reason, the conventional light emitting device has a problem in that since the amount of the resin is increased to increase the volume of the resin portion, the amount of the phosphor per unit volume is reduced and it is not possible to radiate efficiently. In addition, when the volume of the resin portion is increased, there is a problem that the density variation of the phosphor increases and color unevenness occurs.

  The present invention has been made in view of the above points, and an object of the present invention is to efficiently emit light having a certain intensity or more and having a wavelength different from that of light from a light-emitting element. It is an object of the present invention to provide a light emitting device that can emit light with reduced intensity.

The invention according to claim 1 includes a light emitting element that emits light of a predetermined wavelength, a transparent base material disposed in a light emission direction of the light from the light emitting element, and the light emission of the transparent base material. A wavelength converter having a phosphor formed on a surface opposite to the element side and excited by light from the light emitting element to emit light having a wavelength different from that of the light from the light emitting element; A resin that covers the light extraction side of the element and a substrate on which a recess is formed, wherein the light emitting element is provided on a bottom surface of the recess of the substrate, and the resin is filled only on the light emitting element side of the recess. The wavelength conversion section is a hemisphere having an annular cross section, a part of the cross section protrudes inward from the wall surface of the recess of the substrate, and is joined to the substrate at the remaining portion of the cross section. Protruding on the opposite side and the resin Serial wherein the air layer is formed between the transparent substrate.

In this configuration, since the phosphor can be thinly formed without degrading the intensity by the wavelength conversion unit in which the transparent base material and the phosphor are combined, the amount of the phosphor per unit volume can be increased. At the same time, variation in phosphor concentration can be reduced. Accordingly, light having a wavelength different from that of the light from the light emitting element can be efficiently emitted while reducing color unevenness while having a certain intensity or more .

  According to the present invention, light having a wavelength different from that of the light from the light emitting element can be efficiently emitted with reduced color unevenness while having a certain intensity or more.

(Embodiment 1)
Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view illustrating a configuration of the light emitting device according to the first embodiment.

  First, the basic configuration of the first embodiment will be described. As illustrated in FIG. 1, the light-emitting device of Embodiment 1 includes a substrate 1, a semiconductor light-emitting element 2, a sealing resin 3, and a wavelength conversion unit 4.

  A concave portion 10 is formed on the substrate 1 in a mortar shape. The substrate 1 is also formed with a wiring portion (not shown) that is electrically connected to an electrode portion (not shown) of the semiconductor light emitting element 2.

  The semiconductor light emitting element 2 is, for example, a gallium nitride compound semiconductor, and is mounted and fixed at the center of the bottom surface 100 in the recess 10 of the substrate 1. At this time, an electrode portion (not shown) of the semiconductor light emitting element 2 is connected to a wiring portion (not shown) of the substrate 1 by wire bonding or the like, for example. The semiconductor light emitting element 2 emits light having a predetermined wavelength. Specifically, the semiconductor light emitting device 2 is an LED chip in which a gallium nitride based semiconductor layer is formed on a sapphire substrate, and emits blue light.

  The sealing resin 3 has a light-transmitting property, such as an epoxy resin, and fills the bottom surface 100 side of the recess 10 of the substrate 1 to seal the semiconductor light emitting element 2.

  The wavelength conversion unit 4 includes a transparent base material 40 and a phosphor 41, and is arranged in the radiation direction of light from the semiconductor light emitting element 2 so as to cover the concave portion 10 of the substrate 1.

  The transparent substrate 40 is formed into a plate shape with a high strength material such as glass. The transparent base material 40 is larger than the opening of the concave portion 10 of the substrate 1 and is fixed to the substrate 1 with an adhesive or the like at the opening edges 11 and 11 of the concave portion 10. Since the intensity | strength of the wavelength conversion part 4 can be kept more than fixed by the above transparent base materials 40, the wavelength conversion part 4 can endure an impact.

  The phosphor 41 is, for example, a YAG (yttrium aluminum garnet) yellow light-emitting phosphor, and is formed on the upper surface 400 of the transparent substrate 40. As a method of forming the phosphor 41 on the upper surface 400 of the transparent substrate 40, for example, the phosphor 41 is dispersed and held in a resin having translucency such as an epoxy resin, and the resin is dispersed on the upper surface 400 of the transparent substrate 40. There is a method to apply to. As another example, a translucent resin containing the phosphor 41 is formed in advance in a sheet shape, and the sheet resin is bonded to the upper surface 400 of the transparent substrate 40, or the phosphor 41 There is a method of forming the film by vapor deposition or sputtering. The phosphor 41 is formed only on the surface of the transparent substrate 40 and has a small volume. Therefore, the phosphor 41 has a high concentration and a small concentration variation. Such a phosphor 41 is excited by light from the semiconductor light emitting element 2 and emits light having a wavelength different from that of the light from the semiconductor light emitting element 2. Specifically, when blue light is emitted from the semiconductor light emitting element 2, the phosphor 41 is excited by the blue light to emit yellow light.

  Next, a method for manufacturing the light emitting device of Embodiment 1 will be described. First, the recess 10 is formed in the substrate 1 (first step). After the first step, a conductor is laminated in the recess 10 of the substrate 1 and a part of the laminated conductor is removed by etching to form a wiring part (not shown) (second step). After the second step, the semiconductor light emitting element 2 is placed and fixed on the central portion of the bottom surface 100 of the recess 10 (third step). Furthermore, the electrode part (not shown) of the semiconductor light emitting element 2 is connected to the wiring part of the substrate 1 by wire bonding (fourth step). After the fourth step, the sealing resin 3 is filled in the recess 10 until the semiconductor light emitting element 2 is sealed (fifth step). Separately from the first to fifth steps, a translucent resin containing the phosphor 41 is applied to the upper surface 400 of the transparent substrate 40 to form the wavelength conversion unit 4 (sixth step). Finally, the wavelength converter 4 is bonded and fixed to the substrate 1 (seventh step).

  Next, an optical path of light in the light emitting device of Embodiment 1 will be described. The semiconductor light emitting element 2 emits blue light. First, the blue light emitted from the semiconductor light emitting element 2 passes through the sealing resin 3 and reaches the wavelength conversion unit 4. Subsequently, the phosphor 41 formed thin at a high concentration is excited by the blue light reaching the wavelength conversion unit 4 to emit yellow light. Finally, white light is emitted from the wavelength conversion unit 4 to the outside by a combination of blue light emitted from the semiconductor light emitting element 2 and yellow light emitted from the phosphor 41.

  As described above, according to the first embodiment, the phosphor 41 can be formed thin without degrading the intensity by the wavelength conversion unit 4 in which the transparent base material 40 and the phosphor 41 are combined. The amount of the body 41 can be increased, and the concentration variation of the phosphor 41 can be reduced. Accordingly, light having a wavelength different from that of the light from the semiconductor light emitting element 2 can be efficiently radiated while reducing color unevenness while having a certain intensity or more.

  As a modification of the first embodiment, the phosphor may be formed on the lower surface of the transparent substrate (the surface facing the semiconductor light emitting element). Even if it is such a structure, there can exist an effect similar to Embodiment 1. FIG.

(Embodiment 2)
A second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a cross-sectional view illustrating a configuration of the light emitting device according to the second embodiment.

  As shown in FIG. 2, the light-emitting device of Embodiment 2 includes a substrate 1, a semiconductor light-emitting element 2, and a sealing resin 3 in the same manner as the light-emitting device of Embodiment 1 (see FIG. 1). The light emitting device of Embodiment 1 has the following characteristic portions that are not included in the light emitting device.

  The light emitting device of Embodiment 2 includes a wavelength conversion unit 4a as shown in FIG. 2 instead of the wavelength conversion unit 4 of Embodiment 1. The wavelength conversion unit 4a includes a transparent base material 40a and a phosphor 41a, and is disposed in the direction of light emission from the semiconductor light emitting element 2 so as to cover the concave portion 10 of the substrate 1 as in the first embodiment. ing.

  The transparent base material 40a is a hemisphere having a circular cross section 401, the radius of the cross section 401 is longer than the radius of the recess 10, and is fixed to the surface of the substrate 1 by an adhesive or the like by the cross section 401. Since the strength of the wavelength conversion unit 4a can be kept above a certain level by the transparent base material 40a as described above, the wavelength conversion unit 4a can withstand an impact. In addition, the transparent base material 40a is the same as that of the transparent base material 40 (refer FIG. 1) of Embodiment 1 in points other than the above.

  On the other hand, the phosphor 41a is formed on the outer surface 402 of the transparent substrate 40a. The phosphor 41a is formed only on the surface of the transparent substrate 40a and has a small volume. Therefore, the phosphor 41a has a high concentration and a small variation in concentration. The phosphor 41a is the same as the phosphor 41 (see FIG. 1) of the first embodiment except for the points described above. The method of forming the phosphor 41a on the outer surface 402 of the transparent substrate 40a is the same as that in the first embodiment.

  Next, a method for manufacturing the light emitting device of Embodiment 2 will be described. First, the first to fifth steps of the first embodiment are performed to form a recess 10 in the substrate 1 (first step), and a wiring portion (not shown) is formed in the recess 10 (second step). The semiconductor light emitting device 2 is placed and fixed on the bottom surface 100 (third step), the electrode portion (not shown) of the semiconductor light emitting device 2 is connected to the wiring portion of the substrate 1 (fourth step), and the sealing resin 3 is attached. The recess 10 is filled (fifth step). Separately from the first to fifth steps, a light-transmitting resin containing the phosphor 41a is applied to the outer surface 402 of the transparent substrate 40a to form the wavelength conversion unit 4a (sixth step). Finally, the wavelength converter 4a is bonded and fixed to the substrate 1 (seventh step).

  Subsequently, an optical path of light in the light emitting device of Embodiment 2 will be described. The semiconductor light emitting element 2 emits blue light. First, the blue light emitted from the semiconductor light emitting element 2 passes through the sealing resin 3 and reaches the wavelength conversion unit 4a as in the first embodiment. Subsequently, the phosphor 41a thinly formed at a high concentration is excited by the blue light reaching the wavelength conversion unit 4a to emit yellow light, and the white light generated by the blue light and the yellow light is converted into the wavelength conversion unit. 4a is irradiated to the outside.

  As described above, even in the second embodiment, as in the first embodiment, the phosphor 41a can be thinly formed without degrading the intensity by the wavelength conversion unit 4a in which the transparent base material 40a and the phosphor 41a are combined. Therefore, the amount of the phosphor 41a per unit volume can be increased, and the concentration variation of the phosphor 41a can be reduced. Accordingly, light having a wavelength different from that of the light from the semiconductor light emitting element 2 can be efficiently radiated while reducing color unevenness while having a certain intensity or more.

  As a modification of the second embodiment, the phosphor may be formed on the inner surface of the transparent substrate (the surface facing the semiconductor light emitting element). Even if it is such a structure, there can exist an effect similar to Embodiment 2. FIG.

( Reference example )
A reference example will be described with reference to FIG. FIG. 3 is a cross-sectional view illustrating a configuration of a light emitting device of a reference example .

As shown in FIG. 3, the light-emitting device of the reference example includes the substrate 1, the semiconductor light-emitting element 2, and the wavelength conversion unit 4 in the same manner as the light-emitting device of Embodiment 1 (see FIG. 1). The light emitting device according to Embodiment 1 has the following characteristic portions that are not included in the light emitting device.

The light emitting device of the reference example includes a lens 5 as shown in FIG. 3 instead of the sealing resin 3 of the first embodiment. The lens 5 is formed in a hemispherical shape, and is fixed by bonding the central portion of the flat surface 50 to the upper surface 20 of the semiconductor light emitting element 2. The lens 5 collects the light from the semiconductor light emitting element 2 and causes the wavelength conversion unit 4 to emit the light.

Next, a method for manufacturing the light emitting device of the reference example will be described. First, the first to fourth steps of the first embodiment are performed to form a recess 10 in the substrate 1 (first step), and a wiring part (not shown) is formed in the recess 10 (second step). The semiconductor light emitting element 2 is placed and fixed on the bottom surface 100 (third process), and the electrode part (not shown) of the semiconductor light emitting element 2 is connected to the wiring part of the substrate 1 (fourth process). After the first to fourth steps, the lens 5 is fixed to the upper surface 20 of the semiconductor light emitting element 2 (fifth step). Further, the sixth and seventh steps of the first embodiment are performed, and the wavelength conversion unit 4 is formed by applying the phosphor 41 to the upper surface 400 of the transparent substrate 40 (sixth step) as in the first embodiment. The conversion unit 4 is bonded and fixed to the substrate 1 (seventh step).

Subsequently, an optical path of light in the light emitting device of the reference example will be described. The semiconductor light emitting element 2 emits blue light. First, the blue light emitted from the semiconductor light emitting element 2 is collected by the lens 5 and reaches the wavelength conversion unit 4. Subsequently, as in the first embodiment, the blue light reaching the wavelength conversion unit 4 excites the phosphor 41 formed thin at a high concentration to emit yellow light, which is generated by the blue light and the yellow light. The white light is irradiated from the wavelength conversion unit 4 to the outside.

As described above, even in the reference example , the phosphor 41 can be thinly formed without degrading the strength by the wavelength conversion unit 4 in which the transparent base material 40 and the phosphor 41 are combined as in the first embodiment. Therefore, the amount of the phosphor 41 per unit volume can be increased, and the concentration variation of the phosphor 41 can be reduced. Accordingly, light having a wavelength different from that of the light from the semiconductor light emitting element 2 can be efficiently radiated while reducing color unevenness while having a certain intensity or more.

(Embodiment 3 )
Embodiment 3 of the present invention will be described.

The light-emitting device of Embodiment 3 is provided with a plurality of light-emitting devices of Embodiment 1 (see FIG. 1) in a linear or matrix form. More specifically, a plurality of recesses similar to those of the first embodiment are formed on one substrate, and a semiconductor light emitting element is placed and fixed on the central portion of the bottom surface of each of the plurality of recesses. Moreover, the sealing resin similar to Embodiment 1 is filled for every recessed part. Furthermore, a plurality of wavelength converters similar to those of the first embodiment are arranged for each light emission direction from the semiconductor light emitting element.

In the light emitting device of Embodiment 3 , each of the plurality of semiconductor light emitting elements emits blue light, and each of the plurality of phosphors is excited by light from the corresponding semiconductor light emitting element to emit yellow light.

As described above, according to the third embodiment, the same effects as those of the first embodiment can be obtained, the plurality of semiconductor light emitting elements can emit blue light, and the plurality of phosphors can emit yellow light. The illuminance of light radiated to the outside can be increased.

As a modification of the third embodiment, a plurality of light emitting devices according to the second embodiment or the reference example may be provided in a linear shape or a matrix shape. Even in such a configuration, as in the third embodiment, the plurality of semiconductor light emitting elements can emit blue light and the plurality of phosphors can emit yellow light. Can be increased.

It is sectional drawing which shows the structure of the light-emitting device of Embodiment 1 by this invention. It is sectional drawing which shows the structure of the light-emitting device of Embodiment 2 by this invention. It is sectional drawing which shows the structure of the light-emitting device of a reference example .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 10 Recess 2 Semiconductor light emitting element 3 Sealing resin 4 Wavelength conversion part 40 Transparent base material 400 Upper surface 41 Phosphor

Claims (1)

With a light emitting element that emits light of a predetermined wavelength,
The transparent substrate disposed in the light emission direction from the light emitting element, and formed on a surface opposite to the light emitting element side of the transparent substrate, and excited by the light from the light emitting element to emit the light A wavelength converter having a phosphor that emits light having a wavelength different from that of the light from the element;
A resin covering the light extraction side of the light emitting element;
A substrate having a recess formed thereon,
The light emitting element is provided on the bottom surface of the concave portion of the substrate,
The resin is filled only on the light emitting element side of the recess,
The wavelength converting portion is a hemisphere having a circular cross section, and a part of the cross section protrudes inward from the wall surface of the concave portion of the substrate and is bonded to the substrate at the remaining portion of the cross section , opposite to the light emitting element side. Provided to project to the side,
An air layer is formed between the resin and the transparent substrate.

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