Source: https://patents.google.com/patent/JP2008166782A/en
Timestamp: 2019-12-06 15:50:47
Document Index: 734006018

Matched Legal Cases: ['art 25', 'art 25', 'art 25', 'art 25', 'art 25', 'art 25', 'art 25', 'art 25', 'art 25', 'art 23', 'art 23', 'art 23', 'art 25', 'art 25', 'art 25', 'art 25', 'art 25', 'art 26']

JP2008166782A - Light-emitting element - Google Patents
JP2008166782A
JP2008166782A JP2007331710A JP2007331710A JP2008166782A JP 2008166782 A JP2008166782 A JP 2008166782A JP 2007331710 A JP2007331710 A JP 2007331710A JP 2007331710 A JP2007331710 A JP 2007331710A JP 2008166782 A JP2008166782 A JP 2008166782A
JP2007331710A
ヒョク ジョン チョイ
クォン イル パク
2006-12-26 Priority to KR1020060133993A priority Critical patent/KR101297405B1/en
2006-12-28 Priority to KR1020060136442A priority patent/KR101258228B1/en
2007-12-25 Application filed by Seoul Semiconductor Co Ltd, ソウル セミコンダクター カンパニー リミテッド filed Critical Seoul Semiconductor Co Ltd
2008-07-17 Publication of JP2008166782A publication Critical patent/JP2008166782A/en
<P>PROBLEM TO BE SOLVED: To provide a light-emitting element capable of preventing wavelength-converted light from being annihilated to be absorbed in a phosphor again, preventing the wavelength-converted light from being annihilated to be incident on LED again, and further preventing light emitted from the LED emitting long-wavelength light from being lost by the LED and the phosphor emitting short-wavelength light. <P>SOLUTION: The light-emitting element includes the LED which is arranged on a substrate and emits a light of a first wavelength; a transparent molding portion which covers the LED; an underlayer arranged on the transparent molding portion, of a wavelength converting material containing the phosphor which converts the light of the first wavelength emitted from the LED into a light of a second wavelength which is longer than the first wavelength; and an upper layer arranged on the underlayer of the wavelength conversion material, of a wavelength conversion material containing the phosphor which converts the light of the first wavelength, emitted from the LED, into a light of a third wavelength which is longer than the first wavelength and shorter than the second wavelength. <P>COPYRIGHT: (C)2008,JPO&INPIT
The present invention relates to a light emitting device, and more particularly to a light emitting device capable of preventing light emitted from a light emitting diode or wavelength-converted light from being lost inside the light emitting device.
Light emitting devices made of compound semiconductor light emitting diodes can be implemented in color and are widely used for display lamps, lightning plates and displays. In particular, since the light emitting element can realize white light, it has been used as a light source for a liquid crystal display panel and general illumination.
In general, white light can be realized by combining a blue light emitting diode (hereinafter referred to as LED) and a phosphor, and light emission using a blue LED and a YAG phosphor can realize white light. An element is disclosed as Patent Document 1.
However, the above-described technique that realizes white light by mixed light of blue light and yellow light has poor color reproducibility and color rendering due to insufficient light in the red wavelength region. In addition, three LEDs including a blue LED, a green LED, and a red LED can be adopted to realize white light. However, since the wavelength range of the light emitted from the LED is narrow, the color reproducibility is excellent. However, color rendering is not good.
On the other hand, in order to solve the above-mentioned problems, a light emitting device that uses a blue LED, a green phosphor, and a red phosphor, or adopts a red LED together with a blue LED and a phosphor to realize white light is disclosed in Patent Literature. 2 is disclosed.
According to this, white light excellent in color reproducibility and color rendering can be realized by covering the blue LED with a translucent resin containing all of the green phosphor and the red phosphor. In addition, blue reproducibility, green phosphor and red LED can be adopted to improve color reproducibility. Here, the translucent resin containing the green phosphor covers the blue LED, thereby converting a part of the light emitted from the blue LED into green light. Furthermore, examples have been introduced in which blue light, red LED and ultraviolet LED are adopted and white light is realized by covering the ultraviolet LED with a translucent resin containing a green phosphor.
However, in the light emitting element disclosed in Patent Document 2, in the case of a light emitting element adopting blue LED, green and red phosphor, the green phosphor and the red phosphor are distributed in the same translucent resin, Green light emitted from the green phosphor is absorbed by the red phosphor. Generally, phosphors have different wavelength conversion efficiencies depending on excitation wavelengths, and red phosphors that convert light emitted from blue LEDs into red light have wavelength conversion efficiencies that convert blue light into red light. Are better. Therefore, most green light absorbed by the red phosphor is converted into heat and disappears. As a result, when the green phosphor and the red phosphor are all contained in the translucent resin, there is a problem that the green light is insufficient and the light emission efficiency is reduced due to the generation of a large amount of extinguished light.
Further, the light wavelength-converted by the phosphor is incident again on the blue LED. The light incident on the blue LED passes through the blue LED, is absorbed by the bottom surface of the substrate on which the blue LED is mounted, and disappears, so that the light emission efficiency is further reduced.
On the other hand, in the case of a light-emitting element to which a red LED is added, at least a part of red light emitted from the red LED is incident on a translucent resin containing a phosphor and incident on a blue LED or an ultraviolet LED. . The red light incident on the translucent resin does not excite the phosphor, but is scattered and reflected by the phosphor and lost. Further, red light incident on a blue LED or a short wavelength visible light LED is lost due to reflection in the LED. As a result, the intensity of red light becomes weak, and in order to compensate for this, there is a problem that the number of red LEDs used and the drive current of the red LEDs must be increased.
Japanese Patent Laid-Open No. 2002-064220 US Patent Application Publication No. 2004 / 0207313A1
Accordingly, the present invention has been made in view of the above-described problems in the conventional light emitting device, and an object of the present invention is to prevent the wavelength-converted light from being absorbed again by the phosphor and extinguished. Is to provide.
Another object of the present invention is to provide a light emitting element capable of preventing the wavelength-converted light from entering the light emitting diode again and disappearing.
It is another object of the present invention to provide a light emitting element that can prevent light emitted from a light emitting diode that emits light having a long wavelength from being lost by an LED or phosphor that emits light having a short wavelength.
The light emitting device according to the present invention made to achieve the above object includes a light emitting diode disposed on a substrate and emitting light of a first wavelength, a transparent molding portion covering the light emitting diode, and the transparent molding portion. A lower wavelength conversion material layer disposed on the lower wavelength conversion material layer, wherein the lower wavelength conversion material layer includes a phosphor that converts light having a first wavelength emitted from the light emitting diode into light having a longer wavelength than the first wavelength; An upper wavelength converting material layer that includes a phosphor that is disposed and converts light having a first wavelength emitted from the light emitting diode into light having a longer wavelength and further having a wavelength shorter than the second wavelength. It is characterized by having.
Thereby, it is possible to prevent the light converted in wavelength by the wavelength converting material layer from being lost by the phosphor. Further, since the transparent molding part is interposed between the lower wavelength conversion material layer and the light emitting diode, it is possible to reduce the loss of the wavelength converted light that is incident on the light emitting diode again.
Preferably, the refractive index increases in the order of the transparent molding part, the lower wavelength converting material layer, and the upper wavelength converting material layer.
Accordingly, it is possible to prevent the light emitted from the light emitting diode from being lost due to total internal reflection.
The lower wavelength converting material layer may include at least one opening that exposes the transparent molding portion, and the opening may be filled with the upper wavelength converting material layer.
Therefore, a part of the light emitted from the light emitting diode is incident on the upper wavelength conversion material layer without passing through the lower wavelength conversion material layer, and the phosphor contained therein can be excited.
It is preferable that the light of the first wavelength is blue light, the light of the second wavelength is red light, and the light of the third wavelength is green light.
This implements white light.
Meanwhile, the transparent molding part, the lower part and the upper wavelength conversion material layer are preferably formed by molding using a mold.
The transparent molding part may be formed of silicon resin, and the lower and upper wavelength conversion material layers may be formed of epoxy resin.
That is, the transparent molding part has a lower hardness than the lower and upper wavelength conversion material layers. Further, the upper wavelength converting material layer has a higher hardness than the lower wavelength converting material layer.
A lower dielectric multilayer reflecting mirror interposed between the transparent molding part and the lower wavelength converting material layer; and an upper dielectric multilayer film interposed between the lower wavelength converting material layer and the upper wavelength converting material layer It is preferable to further include a reflection mirror.
As a result, the dielectric multilayer film reflecting mirror has a high reflectivity because a dielectric layer having a high refractive index and a dielectric layer having a low refractive index are formed repeatedly. Accordingly, it is possible to prevent the light having the second wavelength converted by the upper wavelength conversion material layer from entering the lower wavelength conversion material layer, and the light having the second wavelength converted by the lower wavelength conversion material layer. Can be prevented from entering the transparent molding part.
The thickness of each dielectric layer in the lower dielectric multilayer reflecting mirror is (2m−1) λ 2 / 4n 2 (where n 2 represents the refractive index of each dielectric layer, and λ 2 is The second wavelength, and m represents an integer of 1 or more).
The thickness of each dielectric layer in the upper dielectric multilayer reflecting mirror is (2k−1) λ 3 / 4n 3 (where n 3 represents the refractive index of each dielectric layer, and λ 3 is And the third wavelength, and k is an integer of 1 or more).
In the above formulas, m and k are preferably 1.
At this time, the upper dielectric multilayer film reflecting mirror is preferably extended between the transparent molding part in the opening and the upper wavelength converting material layer.
According to another aspect of the present invention, there is provided a light emitting device that is disposed on a substrate and that emits light of a first wavelength, covers the first light emitting diode, and the first light emitting device. A wavelength converting material layer containing a phosphor for wavelength-converting at least a part of the first wavelength light emitted from the diode, and disposed on the substrate apart from the first light emitting diode and the wavelength converting material layer; A second light emitting diode that emits light of a second wavelength that is longer than the light of the first wavelength, a dielectric layer having a high refractive index and a dielectric having a low refractive index formed on the wavelength converting material layer; And a dielectric multilayer film reflecting mirror that includes at least a pair of body layers and reflects the light of the second wavelength incident on the wavelength converting material layer.
Accordingly, it is possible to prevent the light emitted from the second light emitting diode from being incident on the wavelength converting material layer and being lost, and to improve the light emission efficiency of the second wavelength light.
Each dielectric layer has a thickness d of d = (2m−1) λ / 4n (where n represents the refractive index of each dielectric layer, λ represents the second wavelength, m preferably represents an integer of 1 or more).
The m is preferably 1.
It is preferable that a sealing resin covering the wavelength converting material layer and the second light emitting diode is further included, and the sealing resin has a relatively low refractive index as compared with the dielectric layer having the high refractive index.
It is preferable to further have a separate second light emitting diode disposed symmetrically with the second light emitting diode with the first light emitting diode as a center.
Accordingly, since the second light emitting diodes are arranged symmetrically with the first light emitting diode as the center, mixed light with uniform luminance can be realized.
The dielectric multilayer film reflecting mirror is preferably formed in a partial region on the wavelength converting material layer.
As a result, the second wavelength light incident on the wavelength converting material layer from the second light emitting diode is reflected, and the light emitted from the first light emitting diode and the light wavelength-converted by the phosphor are lost by the reflection mirror. Can be reduced.
The wavelength converting material layer may be a material layer formed with a uniform thickness on the light emitting diode.
Preferably, the first light emitting diode emits blue light or ultraviolet light having a peak wavelength of 490 nm or less, and the second light emitting diode emits red light having a peak wavelength of 580 nm or more.
According to the light emitting device of the present invention, a plurality of wavelength conversion material layers are adopted to embody mixed light, and on a wavelength conversion material layer containing a phosphor that converts the wavelength into light having a relatively long wavelength, Providing a light emitting device capable of preventing the wavelength-converted light from being lost by the phosphor by disposing a wavelength conversion material layer containing a phosphor that converts the wavelength of light into a relatively short wavelength. There is an effect that can be done.
Further, by disposing a transparent molding part between each wavelength converting material layer and the light emitting diode, it is possible to prevent the light wavelength-converted by the phosphor from being incident again on the light emitting diode and lost. effective.
Further, by adopting the dielectric multilayer film reflecting mirror, there is an effect that it is possible to provide a light emitting diode capable of preventing the wavelength-converted light from being incident again on the phosphor or the light emitting diode and being lost. .
Further, by adopting the dielectric multilayer film reflecting mirror, the light emitted from the second light emitting diode that emits light having a relatively long wavelength is incident on the wavelength conversion material layer, and the phosphor or the short wavelength light. There is an effect that it is possible to provide a light emitting element that can be prevented from being lost by the first light emitting diode that emits light.
Next, a specific example of the best mode for carrying out the light emitting device according to the present invention will be described with reference to the drawings.
The following embodiments are provided as examples for transmitting the idea of the present invention to those skilled in the art. Therefore, the present invention is not limited to the embodiments described below, and may be embodied in other forms. In the drawings, the width, length, thickness, and the like of the components can be exaggerated for convenience of explanation. Like reference numbers throughout the specification indicate like elements.
FIG. 1 is a cross-sectional view of a light emitting device having a plurality of wavelength converting material layers according to a first embodiment of the present invention.
Referring to FIG. 1, a light emitting diode 23 is mounted on a substrate 20. As shown in the drawing, the substrate 20 is a printed circuit board having lead electrodes 21a and 21b, but is not particularly limited as long as a light emitting diode such as a lead frame, a heat sink, or a plastic package body is mounted. The light-emitting diode is formed by growing a GaAlInN-based compound semiconductor layer on a substrate such as sapphire, SiC, or spinel, and can emit light having a first wavelength of ultraviolet light or blue light. .
The light emitting diode 23 is attached to the lead electrode 21a through a conductive adhesive (not shown), and is electrically connected to the lead electrode 21b through a bonding wire. In contrast to this, the light emitting diode 23 is electrically connected to the lead electrodes 21a and 21b through two bonding wires, or is attached on a submount (not shown) to be connected to the lead electrodes 21a and 21b. May be electrically connected.
The transparent molding part 25 is formed on the substrate 20 and covers the light emitting diode 23. Moreover, the transparent molding part 25 can cover a bonding wire.
The transparent molding part 25 is formed of a resin having a relatively small hardness value, for example, a silicon resin. Since the transparent molding part 25 does not contain a phosphor, the light incident on the transparent molding part 25 from the light emitting diode 23 is wavelength-converted near the light emitting diode 23 and is prevented from entering the light emitting diode 23 again. can do.
A lower wavelength converting material layer 27 is disposed on the transparent molding part 25. The lower wavelength converting material layer 27 contains a phosphor that converts the first wavelength light emitted from the light emitting diode 23 into the second wavelength light.
The second wavelength light is longer than the first wavelength light. For example, when the first wavelength light is ultraviolet light or blue light, the second wavelength light is red light. As a result, a part of the first wavelength light emitted from the light emitting diode 23 is converted into the second wavelength light by the phosphor contained in the lower wavelength converting material layer 27.
Further, an upper wavelength conversion material layer 29 is disposed on the lower wavelength conversion material layer 27. The upper wavelength conversion material layer 29 contains a phosphor that converts the first wavelength light emitted from the light emitting diode 23 into the third wavelength light. The third wavelength light is longer than the first wavelength light and shorter than the second wavelength light. For example, when the second wavelength light is red light, the third wavelength light is green light. It is.
In general, a phosphor is excited by excitation light and emits light having a longer wavelength than the excitation wavelength. Therefore, when light having a longer wavelength than the emission wavelength is incident on the phosphor, the longer wavelength light is emitted. Does not excite the phosphor.
Therefore, the second wavelength light wavelength-converted by the phosphor contained in the lower wavelength conversion material layer 27 has a longer wavelength than the emission wavelength of the phosphor contained in the upper wavelength conversion material layer 29. Therefore, the phosphor in the wavelength conversion material layer 29 is not excited. As a result, the second wavelength light wavelength-converted by the lower wavelength conversion material layer 27 is transmitted through the upper wavelength conversion material layer 29 and emitted to the outside.
The lower and upper wavelength converting material layers 27 and 29 are formed of the same material as that of the transparent molding portion 25, but the present invention is not limited thereto, and may be formed of other materials.
At this time, the lower wavelength converting material layer 27 is preferably formed of a material having a higher refractive index than the transparent molding portion 25. The upper wavelength converting material layer 29 is formed of a material having a refractive index equal to or higher than that of the lower wavelength converting material layer 27.
As a result, the light emitted from the light emitting diode 23 is interfaced between the transparent molding part 25 and the lower wavelength converting material layer 27 or the interface between the lower wavelength converting material layer 27 and the upper wavelength converting material layer 29. Loss due to total internal reflection of the light can be prevented, and the light that has been wavelength-converted by the lower and upper wavelength converting material layers 27 and 29 can be reduced from being incident on the inside again.
Further, the lower and upper wavelength converting material layers 27 and 29 are formed of a material having a larger hardness value than the transparent molding portion 25. For example, when the transparent molding part 25 is a silicon resin, the lower and upper wavelength conversion material layers 27 and 29 are each formed of an epoxy resin containing a phosphor. Thereby, the transparent molding part 25 can be prevented from peeling from the substrate 20 and the light emitting diode can be protected from external force.
According to this embodiment, for example, a lower wavelength conversion material layer 27 containing a phosphor that converts blue light into red light is disposed on the light emitting diode 23 that emits blue light. In addition, white light can be realized by disposing the upper wavelength conversion material layer 29 containing a phosphor that converts blue light into green light. When the light emitting diode 23 that emits ultraviolet rays is used, a lower wavelength conversion material layer 27 containing a phosphor that converts ultraviolet rays into red light, and an upper wavelength conversion material containing a phosphor that converts ultraviolet rays into green light. Layer 29 and an additional wavelength converting material layer (not shown) containing a phosphor that converts ultraviolet light into blue light on the upper wavelength converting material layer 29 to realize white light can do.
The transparent molding part 23 and the lower and upper wavelength converting material layers 27 and 29 have a trapezoidal cross section as shown in the figure, but are not limited thereto. The transparent molding part 23 and the lower and upper wavelength conversion material layers 27 and 29 are formed using a molding technique using a mold, and are formed by transfer molding, for example.
Accordingly, the transparent molding part 23, the lower and upper wavelength conversion material layers 27 and 29 are formed in various shapes depending on the shape of the mold. In particular, the upper wavelength converting material layer 29 is formed in a hemispherical shape in order to improve the light emission efficiency, and can have irregularities on the surface thereof.
Further, the type of the phosphor contained in the lower and upper wavelength conversion material layers 27 and 29 is not particularly limited, and for example, a YAG-based, silicate-based, or thiogallate-based phosphor can be used. In particular, the phosphor may be a compound containing lead or copper, such as a silicate phosphor containing lead and copper, as disclosed in Korean Patent Application Publication No. 10-2005-0117164.
FIG. 2 is a cross-sectional view of a light emitting device having a plurality of wavelength conversion material layers according to the second embodiment of the present invention.
Referring to FIG. 2, the light emitting device according to the present embodiment is substantially the same as the light emitting device described with reference to FIG. 1 except that the lower wavelength conversion material layer 27 has an opening 27a. The opening 27 a exposes the transparent molding part 25 and is filled with the upper wavelength conversion material layer 29.
Therefore, part of the light emitted from the light emitting diode 23 is directly incident on the upper wavelength conversion material layer 29 in the opening 27 a without passing through the lower wavelength conversion material layer 27. As a result, the intensity of the light that excites the phosphor in the upper wavelength conversion material layer 29 can be increased.
There may be a plurality of openings 27a, which are dispersed in order to uniformly excite the phosphors in the upper wavelength converting material layer 29.
FIG. 3 is a cross-sectional view of a light emitting device having a plurality of wavelength conversion material layers according to a third embodiment of the present invention.
Referring to FIG. 3, as described with reference to FIG. 1, the light emitting diode 23 is mounted on the substrate 20, the light emitting diode 23 is covered by the transparent molding part 25, and the lower and upper wavelength conversions are performed on the transparent molding part 25. A material layer 2729 is disposed.
However, the lower dielectric multilayer reflective mirror 26 is interposed between the transparent molding part 25 and the lower wavelength converting material layer 27, and the upper dielectric multilayer is interposed between the lower wavelength converting material layer 27 and the upper wavelength converting material layer 29. A film reflecting mirror 28 is interposed.
The lower dielectric multilayer reflecting mirror 26 includes at least a pair of a dielectric layer 26a having a relatively low refractive index and a dielectric layer 26b having a relatively high refractive index. Here, the lower wavelength conversion material layer 27 has a lower refractive index than the high refractive index dielectric layer 26b.
The lower dielectric multilayer reflecting mirror 26 has a thickness of (2m−1) λ 2 / 4n 2 (where n 2 represents the refractive index of each dielectric layer, and λ 2 represents the second wavelength. M represents an integer of 1 or more) and includes at least a pair of a high refractive index dielectric layer 26b and a low refractive index dielectric layer 26a, and reflects light of the second wavelength.
The thickness of each dielectric layer is preferably λ 2 / 4n 2 , that is, m is preferably 1. As the pair of dielectric layers 26a and 26b is stacked a plurality of times, the reflectivity with respect to the light of the second wavelength increases. On the other hand, the lower dielectric multilayer reflection mirror 26 exhibits a light transmission characteristic with respect to the light emitted from the light emitting diode 23.
The upper dielectric multilayer reflecting mirror 28 includes at least a pair of a dielectric layer 28a having a relatively low refractive index and a dielectric layer 28b having a relatively high refractive index, and includes an upper wavelength converting material layer 29. Has a lower refractive index than the high refractive index dielectric layer 28b.
The upper dielectric multilayer reflecting mirror 28 has a thickness of (2k−1) λ 3 / 4n 3 (where n 3 represents the refractive index of each dielectric layer, and λ 3 represents the third wavelength. K represents an integer of 1 or more), and includes at least a pair of a high refractive index dielectric layer 28b and a low refractive index dielectric layer 28a, and reflects light of the third wavelength.
The thickness of each dielectric layer is preferably λ 3 / 4n 3 , that is, k is preferably 1. As the pair of dielectric layers 28a and 28b is laminated a plurality of times, the reflectivity with respect to the light of the third wavelength increases. On the other hand, the upper dielectric multilayer film reflecting mirror 28 exhibits translucency for the light emitted from the light emitting diode 23 and the light of the second wavelength.
As a result, the third wavelength light wavelength-converted by the upper wavelength conversion material layer 29 can be prevented from entering the lower wavelength conversion material layer 27 by the upper dielectric multilayer film reflecting mirror 28, and the lower wavelength can be prevented. The light having the second wavelength converted by the conversion material layer 27 can be prevented from entering the transparent molding portion 25 by the lower dielectric multilayer reflecting mirror 26.
In the present embodiment, the lower wavelength conversion material layer 27 may have an opening as described with reference to FIG. The opening is filled with the upper wavelength converting material layer 29.
At this time, the upper dielectric multilayer film reflecting mirror 28 extends into the opening and is interposed between the upper wavelength converting material layer 29 and the transparent molding part 25 in the opening.
FIG. 4 is a cross-sectional view of a light emitting device having a dielectric multilayer film reflecting mirror according to a fourth embodiment of the present invention, and FIG. 5 is an enlarged partial cross-sectional view of portion A of FIG.
Referring to FIG. 4, a first light emitting diode 51 that emits light having a first wavelength, for example, a blue light emitting diode (first light emitting diode) 51 that emits blue light having a peak wavelength of 490 nm or less is formed on a substrate 50. Be placed. The substrate 50 is the same as the substrate 20 described with reference to FIG. The first light emitting diode 51 is, for example, a GaAlInN-based compound semiconductor, and can be formed by growing a compound semiconductor layer on a substrate such as sapphire, SiC, or spinel.
The wavelength conversion material layer 55 covers the blue light emitting diode (first light emitting diode) 51. The wavelength converting material layer 55 contains a phosphor that converts part of the blue light emitted from the blue light emitting diode (first light emitting diode) 51 into light of other wavelengths, for example, green light and yellow light. The wavelength converting material layer 55 is formed by curing a transparent resin, for example, a silicon resin or an epoxy resin. As shown in the drawing, the wavelength converting material layer 55 has a hemispherical shape, but is not limited to this, and may have various shapes such as a square shape and a trapezoidal shape.
A dielectric multilayer film reflecting mirror 60 is formed on the wavelength converting material layer 55. The dielectric multilayer film reflecting mirror 60 includes at least a pair of a dielectric layer 61 having a relatively high refractive index and a dielectric layer 63 having a relatively low refractive index. As shown in FIG. 5, the dielectric multilayer film reflecting mirror 60 is formed by repeatedly stacking a pair of high refractive index dielectric layers 61a and 61b and low refractive index dielectric layers 63a and 63b a plurality of times 60a and 60b. Structure.
A second light-emitting diode 53, for example, a red light-emitting diode (e.g., a red light-emitting diode) that is spaced apart from the first light-emitting diode 51 and the wavelength conversion material layer 55 and emits light having a second wavelength, which is longer than the first wavelength light, A second light emitting diode) 53 is disposed. The red light emitting diode (second light emitting diode) 53 is made of an AlInGaP-based or GaAs-based compound semiconductor, has a peak wavelength within 580 to 680 nm, and is the same height as the blue light emitting diode (first light emitting diode) 51. Arranged on a plane.
The sealing resin 70 can cover the wavelength converting material layer 55 and the red light emitting diode (second light emitting diode) 53. The sealing resin 70 is formed, for example, by curing a silicon resin or an epoxy resin, and is formed in a shape required for improving the directivity angle or the light emission efficiency using a mold cup. The sealing resin 70 has a relatively low refractive index as compared with the dielectric layer 61 having a high refractive index.
Red light emitted from the red light emitting diode (second light emitting diode) 53 is emitted into the sealing resin 70 and travels in various directions. Part of the red light travels toward the wavelength conversion material layer 55 and reaches the dielectric multilayer film reflection mirror 60. The dielectric multilayer film reflecting mirror 60 is formed so as to have a structure having a high reflectance with respect to red light, and reflects the red light to the outside.
The dielectric multilayer reflection mirror 60 has a thickness d of d = (2m−1) λ / 4n (where n represents the refractive index of each dielectric layer, and λ is emitted from the red light emitting diode). Including at least a pair of a high refractive index dielectric layer 61 and a low refractive index dielectric layer 63 that satisfy the following conditions: .
The thickness d of each dielectric layer is preferably λ / 4n, that is, m is 1. As the pair of dielectric layers 61 and 63 are stacked a plurality of times, the reflectivity for red light increases. On the other hand, the dielectric multilayer film reflecting mirror 60 has translucency characteristics for light emitted from the blue light emitting diode (first light emitting diode) 51 or light converted in wavelength by the phosphor in the wavelength converting material layer 55. Show.
Accordingly, the red light emitted from the red light emitting diode 53 is prevented from entering the wavelength converting material layer 55, thereby preventing the red light from being lost by the wavelength converting material layer 55 and the blue light emitting diode 51. Can do.
Referring to FIG. 6, the light emitting device according to this embodiment includes a blue light emitting diode (first light emitting diode) 51 and a blue light emitting diode (first light emitting diode) (first light emitting diode) 51 disposed on the substrate 50 as described with reference to FIG. A wavelength converting material layer 55 covering the light emitting diode (51), and a red light emitting diode (second light emitting diode) 53 spaced apart from the wavelength converting material layer 55, and further includes a sealing resin 70.
Further, as described with reference to FIGS. 4 and 5, the dielectric multilayer film reflecting mirror 60a includes at least a pair of a high refractive index dielectric layer and a low refractive index dielectric layer. However, unlike the dielectric multilayer film reflecting mirror 60 of FIG. 4, the dielectric multilayer film reflecting mirror 60 a is formed on a partial region of the wavelength conversion material layer 55. That is, the dielectric multilayer film reflecting mirror 60a is limitedly formed on a region that reflects light incident on the wavelength converting material layer 55 from the red light emitting diode (second light emitting diode) 53, and in the remaining region, the wavelength converting material. The surface of layer 55 is exposed.
As a result, the loss of light emitted from the blue light emitting diode (first light emitting diode) 51 to the sealing resin 70 by the dielectric multilayer film reflecting mirror 60a can be reduced.
Referring to FIG. 7, as described with reference to FIG. 4, the blue light emitting diode (first light emitting diode) 51 is disposed on the substrate 50, and the wavelength conversion material layer 55 is the blue light emitting diode (first light emitting diode). 51, a dielectric multilayer film reflecting mirror 60 is formed on the wavelength converting material layer 55.
However, in the present embodiment, the red light emitting diodes (second light emitting diodes) 53 a and 53 b are arranged symmetrically around the blue light emitting diode (first light emitting diode) 51.
Two or more of these red light emitting diodes (second light emitting diodes) 53a and 53b can be arranged, and thereby, the luminance distribution of the red light emitted from the light emitting element and the luminance distribution of the mixed light can be made uniform. it can.
In addition, as described with reference to FIG. 4, the sealing resin 70 can cover the red light emitting diodes (second light emitting diodes) 53 a and 53 b and the wavelength conversion material layer 55.
Referring to FIG. 8, as described with reference to FIG. 4, the blue light emitting diode (first light emitting diode) 81 is disposed on the substrate 50, and the wavelength conversion material layer 85 is the blue light emitting diode (first light emitting diode). 81, a dielectric multilayer reflecting mirror 90 including at least a pair of a dielectric layer 93 having a relatively low refractive index and a dielectric layer 91 having a relatively high refractive index on the wavelength converting material layer 85. Is formed. Further, the red light emitting diode 53 is disposed separately from the wavelength converting material layer 85, and the sealing resin 70 can cover the wavelength converting material layer 85 and the red light emitting diode 53.
However, in the present embodiment, the wavelength converting material layer 85 is formed of a material layer that uniformly covers the blue light emitting diode (first light emitting diode) 81. Such a uniform wavelength converting material layer 85 is formed by placing a blue light emitting diode (first light emitting diode) 81 on a substrate and then by stenciling or the like, or a submount (not shown). A blue light-emitting diode (first light-emitting diode) 81 is bonded to the top and formed using an electrophoresis method. A method of forming a phosphor layer having a uniform thickness by stenciling or electrophoresis is disclosed in, for example, US Pat. Nos. 6,642,652 and 6650044. At this time, the dielectric multilayer film reflecting mirror 90 is also uniformly formed on the wavelength conversion material layer using a technique such as stenciling.
In contrast, the wavelength converting material layer 85 is formed by growing a compound semiconductor layer on a substrate in a blue light emitting diode manufacturing process, forming a plurality of blue light emitting diodes using a photo process and an etching process, and then forming a fluorescent light emitting layer. It is formed by coating a liquid or gel-like transparent organic material containing a body, for example, SOG.
After the wavelength converting material layer 85 is formed on the entire surface of the substrate, a blue light emitting diode (first light emitting diode) 81 having the wavelength converting material layer 85 having a uniform thickness is formed by separating the light converting diode into individual light emitting diodes. The Here, the dielectric multilayer film reflecting mirror 90 is formed on the wavelength conversion material layer 85 before being separated into individual light emitting diodes, or after being separated into individual light emitting diodes, by a process such as stenciling. Form.
According to the present embodiment, since the wavelength conversion material layer 85 containing the phosphor has a uniform thickness, the light emitted from the blue light emitting diode (first light emitting diode) 81 is uniform light in the wavelength conversion material layer 85. By being radiated to the outside through the path, the wavelength-converted light has a uniform light distribution.
In each embodiment of the present invention, the case where the wavelength conversion material layers 55 and 85 cover the blue light emitting diodes (first light emitting diodes) 51 and 81 has been described. However, the present invention is not limited thereto, and instead of the blue light emitting diodes. Other light emitting diodes that emit light of the first wavelength, for example, ultraviolet rays, can also be used. In this case, the wavelength conversion substance layer contains a phosphor that converts the wavelength of ultraviolet light into light in the visible light region, for example, blue light and / or yellow light.
On the other hand, in each embodiment of the present invention, instead of the red light emitting diodes 53, 53a, and 53b, other light emitting diodes that emit light having a second wavelength that is longer than the light having the first wavelength, such as green light emitting diodes, are also included. It can be used.
In the fourth to seventh embodiments of the present invention, the light emitting diodes (51, 81, 53) are electrically connected to lead electrodes (not shown). For this purpose, a submount (not shown) is used. A bonding wire (not shown) may be used, and the light emitting diode may be attached to the lead electrode through a conductive adhesive. On the other hand, the light emitting diodes (51, 81, 53) are electrically connected to the same lead electrode and driven by the same power source. However, the present invention is not limited to this. May be separately driven by different power sources.
1 is a cross-sectional view of a light emitting device having a plurality of wavelength conversion material layers according to a first embodiment of the present invention. It is sectional drawing of the light emitting element which has several wavelength conversion substance layer which concerns on the 2nd Embodiment of this invention. It is sectional drawing of the light emitting element which has several wavelength conversion substance layer which concerns on the 3rd Embodiment of this invention. It is sectional drawing of the light emitting element which employ | adopted the dielectric multilayer film reflective mirror which concerns on the 4th Embodiment of this invention. It is the fragmentary sectional view which expanded the A section of FIG. It is sectional drawing of the light emitting element which employ | adopted the dielectric multilayer film reflective mirror which concerns on the 5th Embodiment of this invention. It is sectional drawing of the light emitting element which employ | adopted the dielectric multilayer film reflective mirror which concerns on the 6th Embodiment of this invention. It is sectional drawing of the light emitting element which employ | adopted the dielectric multilayer film reflective mirror which concerns on the 7th Embodiment of this invention.
20, 50 Substrate 21a, 21b Lead electrode 23 Light emitting diode 25 Transparent molding part 26 Lower dielectric multilayer film reflecting mirror 26a, 28a, 63, 63a, 63b, 93 (low refractive index) dielectric layer 26b, 28b, 61, 61a, 61b, 91 (high refractive index) dielectric layer 27 Lower wavelength converting material layer 28 Upper dielectric multilayer reflecting mirror 29 Upper wavelength converting material layer 51, 81 First light emitting diode 53, 53a, 53b Second light emitting diode 55, 85 Wavelength converting material layer 60, 60a, 90 Dielectric multilayer reflecting mirror 70 Sealing resin
A light emitting diode disposed on a substrate and emitting light of a first wavelength;
A transparent molding part covering the light emitting diode;
A lower wavelength conversion material layer containing a phosphor that is disposed on the transparent molding part and converts light of a first wavelength emitted from the light emitting diode into light of a second wavelength that is longer than the light;
A phosphor disposed on the lower wavelength conversion material layer and converting light having a first wavelength emitted from the light emitting diode into light having a longer wavelength and a wavelength shorter than the second wavelength. And a top wavelength converting material layer containing a light emitting device.
The light emitting device according to claim 1, wherein the refractive index increases in the order of the transparent molding part, the lower wavelength converting material layer, and the upper wavelength converting material layer.
The lower wavelength converting material layer has at least one opening that exposes the transparent molding part, and the opening is filled with the upper wavelength converting material layer. Light emitting element.
The light emitting device according to claim 1, wherein the first wavelength light is blue light, the second wavelength light is red light, and the third wavelength light is green light.
The light emitting device according to claim 1, wherein the transparent molding part, the lower and upper wavelength converting material layers are formed by molding using a mold.
The transparent molding part is formed of silicon resin,
The light emitting device according to claim 5, wherein the lower and upper wavelength converting material layers are formed of an epoxy resin.
A lower dielectric multilayer reflecting mirror interposed between the transparent molding part and the lower wavelength converting material layer;
The light emitting device according to claim 1, further comprising an upper dielectric multilayer film reflecting mirror interposed between the lower wavelength converting material layer and the upper wavelength converting material layer.
The thickness of each dielectric layer in the upper dielectric multilayer reflecting mirror is (2k−1) λ 3 / 4n 3 (where n 3 represents the refractive index of each dielectric layer, and λ 3 is The light-emitting element according to claim 7, wherein the third wavelength is satisfied, and k is an integer of 1 or more.
8. The lower wavelength conversion material layer according to claim 7, wherein the lower wavelength conversion material layer has at least one opening that exposes the transparent molding part, and the opening is filled with the upper wavelength conversion material layer. Light emitting element.
The light emitting device according to claim 9, wherein the upper dielectric multilayer film reflecting mirror is extended between the transparent molding part in the opening and the upper wavelength converting material layer.
A first light emitting diode disposed on the substrate and emitting light of a first wavelength;
A wavelength converting material layer that contains a phosphor that covers the first light emitting diode and converts the wavelength of at least part of the first wavelength light emitted from the first light emitting diode;
A second light emitting diode disposed on the substrate and spaced apart from the first light emitting diode and the wavelength converting material layer and emitting light having a second wavelength longer than the light having the first wavelength;
Reflecting light of the second wavelength incident on the wavelength converting material layer, comprising at least a pair of a dielectric layer having a high refractive index and a dielectric layer having a low refractive index, formed on the wavelength converting material layer And a dielectric multilayer film reflecting mirror.
Each dielectric layer has a thickness d of d = (2m−1) λ / 4n (where n represents the refractive index of each dielectric layer, λ represents the second wavelength, The light emitting element according to claim 11, wherein m represents an integer of 1 or more.
The sealing resin covering the wavelength conversion material layer and the second light emitting diode is further provided, and the sealing resin has a relatively low refractive index as compared with the dielectric layer having the high refractive index. Item 12. The light emitting device according to Item 11.
The light emitting device according to claim 11, further comprising a separate second light emitting diode disposed symmetrically with the second light emitting diode with the first light emitting diode as a center.
The light emitting device according to claim 11, wherein the dielectric multilayer film reflecting mirror is formed in a partial region on the wavelength converting material layer.
The light emitting device of claim 11, wherein the wavelength converting material layer is a material layer formed on the first light emitting diode with a uniform thickness.
The first light emitting diode emits blue light or ultraviolet light having a peak wavelength of 490 nm or less,
The light emitting device according to claim 11, wherein the second light emitting diode emits red light having a peak wavelength of 580 nm or more.
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