CN1372330A - Light-emitting diodes for light conversion with scattered light medium - Google Patents

Abstract

The invention discloses a Light Emitting Diode (LED) or other light emitting device, such as a Laser Diode (LD), comprising a light emitting member and a scattering medium, such as dielectric phosphor (DPP), which absorbs a part of light emitted by the light emitting member and emits light having a wavelength different from that of the absorbed light. The scattering optical media are made of a mixture of crystalline phosphorescent particles and approximately spherical dielectric particles with a band gap greater than 3eV (which do not absorb blue light). Scattering optical media, such as DPP, may also contain phosphorescent particles and bubbles (or pores) instead of dielectric particles. An exemplary LED structure according to a preferred embodiment of the present invention comprises a crystalline semiconductor die encapsulated in an epoxy, a wire connected to the semiconductor die, a metal lead frame connected to the wire, and an epoxy encapsulant covering a scattering optical medium, such as a dielectric phosphor powder. The DPP is made by embedding a mixture of approximately spherical dielectric particles and crystalline phosphor particles in epoxy resin.

Description

Light-emitting diodes that use scattered light media for light conversion

Field of Invention

The present invention relates to a light-emitting diode (LED), in particular to the manufacture of a light-emitting diode that utilizes scattering optical media for light wavelength conversion.

Related Technical Notes

Light emitting diodes (LEDs) are well known solid state light emitting devices that have been widely used in indicators, displays and light sources. Like semiconductor elements, LEDs are characterized by good burn-out rate, vibration resistance, and durable ON/OFF operation.

Conventional LEDs generally emit light in the red portion of the spectrum. For light wavelength conversion, for example, different impurities are used to dope the LED to change the wavelength of the emitted red light. However, the above-mentioned known technology of doping the LED with impurities cannot effectively emit light in all visible spectrum ranges.

Compared to red light, blue light belongs to the short-wavelength part of the visible spectrum. Technologies have been developed to generate a wider range of emitted light from LEDs to exploit the blue part of the spectrum. Blue light with a shorter wavelength, which allows the emission from a blue LED to change to that of other colors in the spectrum, including white light. This can be accomplished by fluorescence or optical wavelength conversion, which is the process of absorbing light of shorter wavelength and re-emitting light of longer wavelength.

Figure 1a is a well-known LED utilizing light wavelength conversion. The LED includes a semiconductor die 1 , wires 2 and 3 , lead frames 4 and 5 , a wavelength conversion substance 6 and an epoxy resin sealant 7 . When a current is applied to the semiconductor die 1, which is a light emitting member of the LED, through the wires 2 and 3 electrically connected to the lead frames 4 and 5, primary light is generated. A wavelength conversion substance 6 containing specific phosphorescence is covered with a light emitting member (ie, semiconductor die 1 ) and molded in a resin. The n-electrode and p-electrode of the semiconductor die 1 are connected to lead frames 4 and 5 through wires 2 and 3, respectively.

For light wavelength conversion, the active element of the LED is the light wavelength conversion substance 6, which partially absorbs primary light from the semiconductor die 1 and generates secondary light. A portion generating light from the semiconductor die 1 (hereinafter referred to as LED light) excites phosphorescence contained in the light conversion substance 6 to generate fluorescence at a wavelength different from that of the LED light. The fluorescent light emitted by the phosphor mixes with the LED light (whose output is not excited by the phosphor) and emits an output. Therefore, the LED outputs light having a different wavelength from the LED light radiated through the light emitting member (ie, the semiconductor die 1 ).

The phosphor contained in the wavelength conversion substance 6 may be a known fluorescent material or a microcrystal of a known and useful garnet fluorescent material. For ultraviolet (UV) primary light emission, the wavelength conversion substance 6 contains dense phosphor powder. Fig. 1b is a well-known LED with light wavelength conversion using dense phosphor powder in conjunction with Fig. 1a. The phosphor powder is embedded in the epoxy resin 9 and densely deposited as a thin covering layer on the surface of the light-emitting component (ie, the semiconductor die 1 ). For the blue primary light emission, the wavelength conversion substance 6 contains diluted phosphor. Fig. 1c is a well-known LED with light wavelength conversion using dilute phosphor in conjunction with Fig. 1a. The phosphor powder is embedded in the epoxy resin 9 and deposited on the surface of the light-emitting member in a diluted ratio, as a thick coating, a blurred spherical or planar layer, or as a lens molded on the semiconductor die 1 .

As far as light wavelength conversion is concerned, known LEDs, such as those disclosed in Figures 1a, 1b and 1c, have problems in controlling the color uniformity of emitted light. The primary light generated by the semiconductor crystal grain 1 is partially blocked by the electrodes of the crystal grain 1 , so that the light is not emitted uniformly in each direction or angle, resulting in a special radiation pattern. However, the phosphor powder contained in the light wavelength conversion substance 6 results in uniform emission of light. Two conflicting phenomena in emission uniformity cause difficulty in controlling light color uniformity via emission angle or direction, which leads to inability to control color differences of light emission.

Therefore, there is a need in the art for an improved LED with light wavelength conversion, which is known to overcome the known problems.

Summary of Invention

The present invention provides a light-emitting diode (LED) or other light-emitting devices, such as a laser diode (laser diode, LD), including: a light-emitting member and a light-scattering medium, such as a dielectric phosphor powder (dielectricphospher powder, DPP). The light emitted by the member emits light having a wavelength different from that of the absorbed light. The use of light scattering or spreading media in LEDs, such as dielectric particles (or any particle with an energy gap greater than 3eV, which does not absorb blue light in the spectrum), improves the light uniformity of the emitted light from the LED.

In a preferred embodiment of the invention, the LED comprises crystalline semiconductor dies as light emitting means. Dielectric phosphor powder is made of a mixture of approximately spherical micro-media particles and phosphorescent particles. The spherical dielectric particles can also be made of wide-gap semiconductors or transparent media. The DPP forms a light-scattering medium, and its refractive index, scattering properties, and light conversion properties are controlled by the refractive index and the radius of the medium particles. The use of DPP in LEDs allows for efficient light extraction of LED light-emitting components (e.g., crystalline semiconductor dies), efficient light wavelength conversion, and generally uniform color over all radiation angles compared to conventional LEDs without DPP for light conversion Distribution and wider light emission angles produced by LEDs with DPP.

The light-scattering medium, such as DPP, may also contain phosphorescent particles and air bubbles (or pores) instead of medium particles. The bubble energy gap of this DPP is greater than 3eV, which does not absorb blue light in the spectrum. The bubbles can be air bubbles, nitrogen bubbles and inert gas bubbles. Furthermore, the DPP can also be a mixture of air bubbles, dielectric particles and phosphorescent particles.

According to another embodiment, the present invention provides a light-emitting diode (LED), comprising: a light-emitting member (for example, a crystalline semiconductor grain), and a light-scattering medium, such as a dielectric phosphor powder (DPP), and the light-scattering medium is composed of a crystal It is made of a mixture of high-quality phosphorescent particles and approximately spherical micro-media particles.

According to another embodiment, the present invention provides a light-emitting diode (LED), comprising: a light-emitting member (for example, an aluminum indium gallium nitride (AlInGaN) crystalline semiconductor grain), encapsulated in a light-scattering medium, such as a medium phosphorescent powder (DPP). The DPP is made of a mixture of approximately spherical micro-media particles of microcrystalline aluminum nitride (AlN). The LEDs according to this particular embodiment may also be white LEDs.

According to another embodiment, the present invention provides a light-emitting diode (LED), comprising: a light-emitting component, such as an InGaN semiconductor die, encapsulated in a light-scattering medium, such as a dielectric phosphor (DPP). This DPP is a mixture of nearly spherical micro-media particles of amorphous silicon nitride (Si ₃ N ₄ ) with a radius of 50 to 5000 nm and microcrystals of garnet fluorescent materials with a radius of 1000 to 10000 nm. made by. The LEDs according to this particular embodiment may also be white LEDs.

According to another embodiment, the present invention provides a light-emitting diode (LED), comprising: a light-emitting component, such as aluminum indium gallium nitride (AlInGaN) semiconductor die, encapsulated in a light-scattering medium, such as dielectric phosphor (DPP). This DPP is made of a mixture of nearly spherical micro-media particles of amorphous silicon dioxide (SiO ₂ ) with a radius between 50 and 5000 nm and microcrystals of garnet fluorescent materials with a radius between 1000 and 10000 nm. become. The LEDs according to this particular embodiment may also be white LEDs.

According to yet another embodiment, the present invention provides a light-emitting diode (LED), comprising: a light-emitting component, such as an InGaN semiconductor die, encapsulated in a light-scattering medium, such as a dielectric phosphor (DPP). This DPP is made of a mixture of nearly spherical micro-media particles of amorphous gallium nitride (GaN) with a radius between 50 and 5000 nm and microcrystals of garnet fluorescent materials with a radius between 1000 and 10000 nm. . The LEDs according to this particular embodiment may also be white LEDs.

The exemplary LED structure according to the preferred embodiment of the present invention includes: crystalline semiconductor die, encapsulated in epoxy resin; wiring, connected to the semiconductor chip; metal lead frame, connected to the wiring; and epoxy resin encapsulant, covering the scattering Optical media such as Dielectric Phosphor Powder (DPP). The DPP is made of a mixture of approximately spherical dielectric particles and crystalline phosphorescent particles embedded in epoxy resin.

Brief description of attached drawings

In order to make the above and other advantages and features of the present invention more comprehensible, the preferred embodiments will be described in detail below with reference to the accompanying drawings. in:

Figure 1a is a schematic diagram of a known light-emitting diode with light wavelength conversion;

Figure 1b is a schematic diagram of a well-known light-emitting diode with light wavelength conversion using dense phosphor powder in conjunction with Figure 1;

Figure 1c is a schematic diagram of a known light-emitting diode with light wavelength conversion using dilute phosphors in conjunction with Figure 1 .

Figure 1d is a schematic diagram of light wavelength conversion using a light-scattering medium such as dielectric phosphor powder (DPP) according to the present invention;

2a and 2b are schematic diagrams of light-emitting diodes with light wavelength conversion using a light-scattering medium, such as dielectric phosphor powder (DPP), according to another embodiment of the present invention; and

3a and 3b are schematic diagrams of light-emitting diodes or other light-emitting devices such as laser diodes (LDs) with light wavelength conversion using a light-scattering medium such as dielectric phosphor powder (DPP) according to yet another embodiment of the present invention.

Symbol Description

1, 10, 31 ~ semiconductor grains;

2, 3, 20, 30, 32, 33 ~ wiring;

4, 5, 34, 35, 40, 50 ~ metal lead frame;

6, 36, 60 ~ wavelength conversion substances;

7, 37, 70 ~ sealing glue;

8d, 120, 312～Garnet fluorescent material microcrystals;

9, 39, 90 ~ epoxy resin;

10d, 110, 311 ~ medium particles.

Detailed Description of Preferred Embodiments

FIG. 1d is a schematic diagram of light wavelength conversion using a light-scattering medium, such as dielectric phosphor powder (DPP), for application to the LED of FIG. 1a according to the present invention. The wavelength converting substance 6 of Fig. 1a is replaced by a dielectric phosphor or DPP. The DPP according to the present invention is made by embedding a mixture of approximately spherical micro-media particles and crystalline phosphorescent particles in epoxy resin 9d. The use of light scattering or spreading media in LEDs, such as dielectric particles (any particle with an energy gap greater than 3 eV), improves the light uniformity of the light emitted by the LED. The weight or volume concentration of crystalline phosphorescent particles embedded in the epoxy resin 9d depends on the thickness of the epoxy resin layer and the size and distribution of the phosphorescent particles. The concentration of phosphorescent particles is generally 2% to 25% of the total volume of the dielectric phosphor powder (DPP). The phosphorescent particles according to the present invention comprise gadolinium (Gd), yttrium (Y), cerium (Ce) and neodymium (Nd) based phosphors.

Dielectric phosphorescent powder (DPP) is made of a mixture of approximately spherical micro-media particles and phosphorescent particles. Spherical dielectric microparticles can be made of wide-gap semiconductors or transparent dielectrics. The DPP forms a light-scattering medium, and its refractive index, scattering properties, and light conversion properties are controlled by the refractive index and the radius of the medium particles. The use of DPP in LEDs allows for efficient light extraction of LED light-emitting components (e.g., crystalline semiconductor dies), efficient light wavelength conversion, and generally uniform color over all radiation angles compared to conventional LEDs without DPP for light conversion Distribution and wider light emission angles produced by LEDs with DPP.

The light-scattering medium, such as DPP, may also contain phosphorescent particles, and bubbles (or pores) instead of medium particles. The bubble energy gap of this DPP is greater than 3eV. The bubbles are naturally spherical due to their surface tension and function as light scattering media for the light wavelength conversion of the present invention. The bubbles may be air bubbles, nitrogen (N ₂ ) bubbles or inert gas bubbles. This air bubble is set on the epoxy resin 9d by injecting gas corresponding to the air bubble during the molding of the epoxy resin 9d. Furthermore, the DPP can also be a mixture of air bubbles, dielectric particles and phosphorescent particles.

The LED structure according to a specific embodiment of the present invention includes: crystalline semiconductor grains, a dielectric phosphorescent powder (DPP) made of a mixture of approximately spherical micro-media particles and crystalline phosphorescent particles embedded in epoxy resin 9d, Wiring, connected to the semiconductor die, metal lead frame, connected to the wiring to carry current to the semiconductor die, and epoxy encapsulant, covering the dielectric phosphor or DPP.

According to another embodiment of the present invention, the light-scattering medium, such as DPP, is made of approximately spherical microcrystalline aluminum nitride (AlN) micromedia particles. According to another embodiment of the present invention, the DPP is composed of nearly spherical micro-media particles of amorphous silicon nitride (Si ₃ N ₄ ) with a radius between 50 and 5000 nm and a particle with a radius between 1000 and 10000 nm. Made of a mixture of microcrystals of the garnet fluorescent material. In another embodiment, the DPP is composed of approximately spherical micro-media particles 10d of amorphous silicon dioxide (SiO ₂ ) with a radius between 50 and 5000 nm and garnet fluorescent particles with a radius between 1000 and 10000 nm. A mixture of microcrystals 8d of material embedded in epoxy resin 9d. According to another embodiment, the DPP is composed of approximately spherical micro-media particles 10d of amorphous gallium nitride (GaN) with a radius between 50 and 5000 nm and garnet fluorescent particles with a radius between 1000 and 10000 nm. A mixture of microcrystals 8d of material embedded in epoxy resin 9d.

2a and 2b are schematic diagrams illustrating a light-emitting diode with light wavelength conversion using a light-scattering medium, such as dielectric phosphor powder (DPP), according to another embodiment of the present invention. The present invention provides an LED, comprising: a light-emitting member and a light-scattering medium, such as dielectric phosphor powder (DPP). The DPP absorbs part of the light emitted by the light-emitting member and emits light with a wavelength different from the absorbed light. In a preferred embodiment according to the present invention, the LED comprises a crystalline semiconductor die (indium gallium nitride (InGaN) crystalline semiconductor die 10 ) as a light emitting member. The DPP is made of a mixture of approximately spherical dielectric particles and crystalline phosphorescent particles embedded in epoxy resin 70 . The weight or volume concentration of the crystalline phosphorescent particles embedded in the epoxy resin sealant 90 depends on the thickness of the epoxy resin layer and the size and distribution of the phosphorescent particles. The concentration of phosphorescent particles may range from 2% to 25% by volume. The use of phosphorescent particles according to the present invention includes gadolinium (Gd), yttrium (Y), cerium (Ce) and neodymium (Nd) based phosphors. In particular, the DPP wavelength conversion substance 60 is composed of approximately spherical micro-media particles 110 of amorphous silicon nitride (Si ₃ N ₄ ) with a radius between 50 and 5000 nm and pomegranate particles with a radius between 1000 and 10000 nm. The mixture of microcrystals 120 of stone fluorescent material embedded in epoxy resin 90 is made. The semiconductor die 10 , as the light-emitting component in the LED, generates primary light when current is applied to the die 10 through the wires 20 and 30 electrically connected to the metal lead frames 40 and 50 . The wavelength conversion substance 60 containing DPP covers the light-emitting member (ie, the semiconductor die 10 ) and is molded in a resin. The n-electrode and p-electrode of the semiconductor die 10 are electrically connected to the metal lead frames 40 and 50 through the wires 20 and 30 respectively.

The light-scattering medium, such as DPP, can also contain phosphorescent particles, and the medium particles are replaced by bubbles (or pores). The energy gap of the bubbles in the DPP is larger than 3eV. The bubbles are naturally spherical due to their surface tension and function as light scattering media for the light wavelength conversion of the present invention. The bubbles may be air bubbles, nitrogen (N ₂ ) bubbles or inert gas bubbles. The air bubbles are set on the epoxy 90 by injecting gas corresponding to the air bubbles during the molding of the epoxy 90 . Furthermore, the DPP can also be a mixture of air bubbles, dielectric particles and phosphorescent particles.

The LED structure according to a specific embodiment of the present invention includes: crystalline semiconductor crystal grain 10, encapsulated in a light-scattering medium, such as dielectric phosphor powder (DPP), which is composed of a mixture of approximately spherical micro-media particles and crystalline phosphorescent particles Embedded in epoxy resin 90, wires 20 and 30, connected to semiconductor die 10, metal lead frames 40 and 50, connected to wires to transmit current to semiconductor die and epoxy resin sealant 90, covering scattering Optical media such as dielectric phosphor or DPP.

The light-emitting component used in the LED is a gallium nitride compound semiconductor, which can effectively excite the garnet fluorescent material in the DPP. The light-emitting member in the LED is made by forming an indium gallium nitride (InGaN) light-emitting layer on a substrate during the semiconductor manufacturing process. The structure of the light emitting member may be a homostructure, a heterostructure or a double heterostructure.

In a specific embodiment according to the invention, when an electric current is applied to the crystalline semiconductor die 10, primary blue-green light with a wavelength _λp between 400 and 500 nm is generated. The DPP wavelength conversion substance 60 absorbs the primary blue-green light and generates secondary yellow-orange light with a wavelength λ _s between 550 and 660 nm. As a result, the light emitted by the LED with DPP is the sum of the blue-green light wavelength λ _p and the yellow-orange light wavelength λ _s , which appears as white light to human eyes.

The color quality of the white light depends on the distribution of all radiation angles of the intensity ratio of the primary blue-green light and the secondary yellow-orange light, and is controlled by the DPP wavelength conversion substance 60 . The DPP wavelength conversion material 60 is composed of approximately spherical micro-media particles 110 of amorphous silicon nitride (Si ₃ N ₄ ) with a radius R _s between R _s =50 and 1000 nm and a radius R _m at R _m =1000 nm It is made by embedding the mixture of microcrystals 120 of garnet fluorescent material between 10000 nm and embedded in epoxy resin 90 . The light-scattering properties of Si ₃ N ₄ approximately spherical micro-media particles strongly depend on R _s , where R _s =λ _p / _2λne , and _ne =1.3 to 1.5, which is the value of epoxy resin sealant 70 refractive index. This allows control of the angular distribution of the primary blue-green and secondary yellow-orange intensity ratios and the quality of white light emitted by LEDs with control over the radius R _s of amorphous Si ₃ N ₄ near-spherical micromedia particles.

Since the refractive index n _s =2.05 of the Si ₃ N ₄ spherical particles is close to the refractive index of the InGaN crystalline semiconductor grain 10 (where n _c =2.3 to 2.8) and the epoxy resin sealant 70 (where n _e =1.3 to 1.5) The square root of multiplication, so the use of DPP in the LED according to the present invention effectively improves the primary light extraction of the semiconductor die 10 .

According to another embodiment, the present invention provides a light-emitting diode (LED), comprising: a light-emitting member (such as an aluminum indium gallium nitride (AlInGaN) crystalline semiconductor grain 10), encapsulated in a light-scattering medium, such as dielectric phosphorescence powder (DPP). The light-scattering medium, such as the DPP wavelength conversion material 60 , is made of a mixture of nearly spherical micro-media particles of microcrystalline aluminum nitride (AlN) embedded in epoxy resin 90 . According to yet another embodiment, the present invention provides a light emitting diode (LED), comprising: a light emitting component, such as an aluminum indium gallium nitride (AlInGaN) crystalline semiconductor grain 10 , encapsulated in a dielectric phosphor powder (DPP). The DPP wavelength conversion substance 60 is embedded in epoxy resin 90 by a mixture of amorphous gallium nitride (GaN) with a radius of 50 to 5000 nm and garnet fluorescent material with a radius of 1000 to 10000 nm. made by.

3a and 3b are schematic diagrams of light-emitting diodes or other light-emitting devices such as laser diodes (LDs) with light wavelength conversion using a light-scattering medium such as dielectric phosphor powder (DPP) according to another embodiment of the present invention. The present invention provides an LED (or other light-emitting devices, such as LD), including: a light-emitting member, such as a transparent sealant, and a light-scattering medium, such as pores or dielectric phosphor powder (DPP), and the light-scattering medium absorbs a part of the light emitted by the light-emitting member The emitted light emits light of a wavelength different from that of the absorbed light. Add directly to the transparent sealant 37 of the LED in the scattered light medium, and the sealant 37 is selected from: hemispherical lens, epoxy resin, lenticular lens, sheet glass, polymethyl methacrylate (polymethyl methacylate, PMMA) sheet plastic and polycarbonate (polycarbonate) sheet plastic.

In another preferred embodiment according to the present invention, the LED comprises a crystalline semiconductor die (indium gallium nitride (InGaN) crystalline semiconductor die 31 ) as a light emitting member. The DPP is made by embedding a mixture of approximately spherical dielectric particles and grain phosphorescent particles in the transparent encapsulant 37 . The weight or volume concentration of crystalline phosphorescent particles embedded in the epoxy resin 39 depends on the thickness of the epoxy resin layer and the size and distribution of the phosphorescent particles. The concentration of phosphorescent particles may range from 2% to 25% by volume. The use of phosphorescent particles according to the present invention includes gadolinium (Gd), yttrium (Y), cerium (Ce) and neodymium (Nd) based phosphors. In particular, the DPP wavelength conversion substance 36 is composed of approximately spherical micro-media particles 311 of amorphous silicon dioxide (SiO ₂ ) with a radius between 50 and 1000 nm and garnet fluorescent particles with a radius between 1000 and 10000 nm. A mixture of crystallites 312 of material embedded in epoxy resin 39 is produced. The semiconductor die 31 , as a light-emitting component in the LED, generates primary light when current is applied to the die 31 through the wires 32 and 33 electrically connected to the metal lead frames 34 and 35 . The wavelength conversion substance 36 containing DPP covers the light emitting member (ie, the semiconductor die 31 ) and is molded in resin. The n-electrode and p-electrode of the semiconductor die 31 are electrically connected to metal lead frames 34 and 35 through wires 32 and 33 respectively.

The light-scattering medium, such as DPP, can also contain phosphorescent particles, and the medium particles are replaced by air bubbles (or pores). The bubble energy gap of this DPP is greater than 3eV. The bubbles are naturally spherical due to their surface tension and function as light scattering media for the light wavelength conversion of the present invention. The bubbles may be air bubbles, nitrogen (N ₂ ) bubbles or inert gas bubbles. This air bubble is provided on the epoxy resin 39 by injecting gas corresponding to the air bubble during the molding of the epoxy resin 39 . Furthermore, the DPP can also be a mixture of air bubbles, dielectric particles and phosphorescent particles.

The LED structure according to a specific embodiment of the present invention includes: a crystalline semiconductor die 31, encapsulated in a transparent sealant 37, wires 32 and 33, connected to the semiconductor die 31, metal lead frames 34 and 35, connected to the wires and Transmit current to the semiconductor die 31 and the epoxy resin sealant 39, covering the scattering light medium, such as dielectric phosphor powder (DPP), which is embedded in the epoxy resin 37 by a mixture of approximately spherical micro-dielectric particles and crystalline phosphorescent particles made by. The light-scattering medium is directly added to the transparent sealant 37 of the LED, and the sealant 37 is selected from: hemispherical lens, epoxy resin, lenticular lens, sheet glass, polymethyl methacrylate (polymethyl methacylate, PMMA) ) sheet plastic and polycarbonate (polycarbonate) sheet plastic. In this embodiment, the transparent sealant 37 shown in FIG. 3a is a hemispherical lens.

In a specific embodiment according to the present invention, when an electric current is applied to the crystalline semiconductor grain 31 , primary blue-green light with a wavelength λ _p between 400 and 500 nm is generated. The DPP wavelength conversion substance 36 absorbs the primary blue-green light and generates secondary yellow-orange light with a wavelength λ _s between 550 and 660 nm. As a result, the light emitted by the LED with DPP is the sum of the blue-green light wavelength λ _p and the yellow-orange light wavelength λ _s , which appears as white light to human eyes.

The color quality of the white light depends on the distribution of all radiation angles of the intensity ratio of the primary blue-green light and the secondary yellow-orange light, and is controlled by the DPP wavelength conversion substance 36 . The DPP wavelength conversion material 36 is an approximately spherical micro-media particle 311 of amorphous silicon dioxide (SiO ₂ ) with a radius R _s between R _s = 50 to 1000 nm and a radius between R _m = 1000 to 10000 nm The mixture of microcrystals 312 of garnet fluorescent material embedded in epoxy resin 39 is made. The light scattering properties of the approximately spherical micromedia particles of SiO ₂ strongly depend on R _s , where R _s =λ _p / _2λne , and _ne =1.3 to 1.5, which is the refractive index of the transparent encapsulant 37 . This allows control of the angular distribution of the primary blue-green and secondary yellow-orange intensity ratios and the quality of white light emitted by LEDs with control of the radius R _s of the approximately spherical micromedia particles of amorphous SiO ₂ .

Other materials that can be used in garnet fluorescent materials (for example, 120 in FIG. 2b and 312 in FIG. 3b ) include phosphorescent garnet fluorescent materials activated by cerium, which include at least one selected from yttrium (Y), lutetium (Lu) , scandium (Sc), lanthanum (La), gadolinium (Gd) and samarium (Sm) elements and at least one element selected from aluminum (Al), gallium (Ga) and indium (In) elements. For example, phosphors such as yttrium aluminum garnet (YAG phosphor) activated by cerium can be used in the DPP according to the invention.

Other materials that can be used as garnet fluorescent materials include: Ag: ZnS (blue), CuAuAl: ZnS (green), CuAl: ZnS (green), Mg ₄ (F)GeO ₅ : Mn (red) or Ce : Phosphorescence of YAG (yellow-green). Other materials that can be used as garnet fluorescent materials include: Coumarin6 (high-quality green, very efficient), Fluorol 7GA (yellow-green, very efficient), DOCI (green, short decay length), Phosphorescence of Rhodamine 110 (yellow, very efficient), DCM (orange, moderate efficiency), Pyridine 1 (red, poor efficiency) or Pyridine 2 (deep red, poor efficiency) quality.

Although discussed here in relation to LEDs, it will be appreciated that the method according to the invention is also beneficial for other light sources (eg planar light sources, laser diodes). Again, while some of the discussion herein is in relation to white LEDs, it will also be appreciated that emitters of other wavelengths are also beneficial in the method according to the invention. Fields of application of the LED with DPP according to the invention include at least electronics, instrumentation, electronic equipment, and outdoor type displays, displays for automobiles, aircraft, or any other lighting equipment.

Although the present invention has been described above in detail with preferred embodiments, the embodiments are not intended to limit the exact form of the present invention disclosed herein, and any person skilled in the art, without departing from the spirit and scope of the present invention, when Changes and modifications can be made, and similarly, any preparation steps disclosed herein can also be replaced by other steps to achieve substantially the same results, so all changes included in the scope of the present invention should be treated with the appended claims Whichever is defined shall prevail.

Claims (37)

1. A light emitting diode, comprising: a light-emitting member to emit light, including a transparent sealant; and A light-scattering medium is added to the transparent substrate. 2. The light emitting diode of claim 1, wherein the scattering light medium is selected from the group consisting of air bubbles, nitrogen gas bubbles and inert gas bubbles. 3. The light emitting diode of claim 1, wherein the light-scattering medium has an energy gap greater than 3 eV. 4. The light emitting diode of claim 1, wherein the light scattering medium does not absorb blue light. 5. The light emitting diode of claim 1, further comprising: a crystalline semiconductor die, wherein the light-scattering medium is embedded in the epoxy resin; wires connected to the semiconductor die; and A metal lead frame is connected to the wires to transmit current to the semiconductor die. 6. The light emitting diode of claim 1, further comprising: Crystalline semiconductor crystal grains, sealed in the scattering light medium; wires connected to the semiconductor die; and a metal lead frame connected to the wires to transmit current to the semiconductor die; Wherein the semiconductor grains are selected from: nitride compound semiconductor grains, gallium nitride compound semiconductor grains, crystalline indium gallium nitride semiconductor grains and crystalline aluminum indium gallium nitride semiconductor grains. 7. The light-emitting diode of claim 1, wherein the transparent encapsulant further comprises a garnet fluorescent material selected from the group consisting of gadolinium, yttrium, cerium, and neodymium-based phosphorescence. 8. The light-emitting diode of claim 1, wherein the transparent sealant further comprises a garnet fluorescent material selected from the group consisting of: Ag:ZnS, CuAuAl:ZnS, CuAl:ZnS, Mg ₄ (F)GeO ₅ :Mn and Ce:YAG . 9. The light emitting diode of claim 1, wherein the transparent sealant further comprises a garnet fluorescent material selected from the group consisting of: Coumarin, Fluorol 7GA, DOCI, Rose Bengal, DCM, Pyridine 1 and Pyridine 2. 10. The light emitting diode of claim 1, wherein said light scattering medium is a mixture of phosphorescent particles and pores. 11. The light-emitting diode of claim 1, wherein the light-scattering medium further comprises a dielectric phosphor powder made of crystalline phosphor particles and dielectric particles. 12. The light emitting diode of claim 11, wherein the concentration of said phosphorescent particles is 2% to 25% of the total volume of said dielectric phosphor. 13. The light emitting diode of claim 11, wherein the dielectric particles are selected from the group consisting of: microcrystalline aluminum nitride, amorphous silicon nitride, amorphous gallium nitride, and amorphous silicon dioxide. 14. The light emitting diode of claim 11 , wherein said dielectric particles are selected from the group consisting of: amorphous silicon nitride with a radius between 50 and 5000 nm, amorphous silicon dioxide with a radius between 50 and 5000 nm, and a radius between 50 and 50 nm. Amorphous gallium nitride to 5000nm. 15. The light emitting diode of claim 11, wherein said phosphorescent particles are microcrystals of garnet fluorescent material with a radius between 1000 and 10000 nm. 16. The light emitting diode of claim 11, wherein said phosphorescent particles are selected from the group consisting of gadolinium, yttrium, cerium and neodymium based phosphors. 17. The light emitting diode of claim 11 , wherein said phosphorescent particles comprise at least one element selected from the group consisting of yttrium, lutetium, scandium, lanthanum, gadolinium, and samarium and at least one other element selected from the group consisting of aluminum, gallium, and indium. Ce-activated garnet fluorescent material. 18. The light emitting diode of claim 11, wherein the transparent sealant is selected from the group consisting of hemispherical lens, epoxy resin, lenticular lens sheet, thin glass, polymethylmethacrylate sheet plastic and polycarbonate sheet plastic. 19. The light emitting diode of claim 1, wherein the scattering light medium absorbs a part of the light emitted by the light emitting member and emits light having a wavelength different from that of the absorbed light. 20. The light emitting diode of claim 1, wherein the light emitting diode is replaced by a laser diode (LD). 21. A laser diode comprising: a light-emitting member to emit light, including a transparent sealant; and A light-scattering medium is added to the transparent substrate. 22. The laser diode of claim 21, wherein said light-scattering medium is selected from the group consisting of air bubbles, nitrogen gas bubbles, and inert gas bubbles. 23. The laser diode of claim 21, wherein the light-scattering medium has an energy gap greater than 3 eV. 24. The laser diode of claim 21, wherein said light scattering medium does not absorb blue light. 25. The laser diode of claim 21, wherein the transparent encapsulant further comprises a phosphorescent garnet material selected from the group consisting of gadolinium, yttrium, cerium, and neodymium-based phosphorescence. 26. The laser diode according to claim 21, wherein said transparent sealant further comprises a garnet fluorescent material selected from the group consisting of: Ag:ZnS, CuAuAl:ZnS, CuAl:ZnS, Mg ₄ (F)GeO ₅ :Mn and Ce:YAG . 27. The laser diode of claim 21, wherein the transparent encapsulant further comprises a garnet fluorescent material selected from the group consisting of Coumarin, Fluorol 7GA, DOCI, Rose Bengal, DCM, Pyridine 1 and Pyridine 2. 28. The laser diode of claim 21, wherein said light scattering medium is a mixture of phosphorescent particles and pores. 29. The laser diode of claim 21, wherein said light-scattering medium further comprises a dielectric phosphor powder made of crystalline phosphor particles and dielectric particles. 30. The laser diode of claim 29, wherein the concentration of said phosphorescent particles is 2% to 25% of the total volume of said dielectric phosphor. 31. The laser diode of claim 29, wherein said dielectric particles are selected from the group consisting of microcrystalline aluminum nitride, amorphous silicon nitride, amorphous gallium nitride, and amorphous silicon dioxide. 32. The laser diode of claim 29, wherein said dielectric particles are selected from the group consisting of: amorphous silicon nitride with a radius between 50 and 5000 nm, amorphous silicon dioxide with a radius between 50 and 5000 nm, and a radius between 50 and 500 nm. Amorphous gallium nitride to 5000nm. 33. The laser diode of claim 29, wherein said phosphorescent particles are microcrystals of garnet fluorescent material having a radius between 1000 and 10000 nm. 34. The laser diode of claim 29, wherein said phosphorescent particles are selected from the group consisting of gadolinium, yttrium, cerium and neodymium based phosphors. 35. The laser diode of claim 29, wherein said phosphorescent particles comprise at least one element selected from the group consisting of yttrium, lutetium, scandium, lanthanum, gadolinium, and samarium and at least one other element selected from the group consisting of aluminum, gallium, and indium. Ce-activated garnet fluorescent material. 36. The laser diode of claim 21, wherein the transparent encapsulant is selected from the group consisting of hemispherical lens, epoxy resin, lenticular lens sheet, glass sheet, polymethyl methacrylate sheet plastic, and polycarbonate sheet plastic. 37. The light emitting diode of claim 21, wherein said scattering light medium absorbs a part of light emitted by said light emitting member and emits light having a wavelength different from said absorbed light.

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