CN105957946A - LED (Light Emitting Diode) flip lighting device close to natural spectrum - Google Patents

Abstract

The invention discloses an LED flip-chip lighting device close to natural spectrum. The device includes an LED flip chip, wherein a phosphor layer and a transparent fluorescent ceramic layer are sequentially arranged on the flip chip, and the phosphor layer surrounds the LED flip chip, and the transparent fluorescent ceramic layer covers on the upper surface of the phosphor layer. The device has good spectral continuity, high color rendering, and high luminous efficiency, which well meets the needs of lighting LEDs.

Description

A near-natural spectrum LED flip-chip lighting device

technical field

The invention belongs to the field of LED lighting and relates to an LED flip-chip lighting device close to natural spectrum.

Background technique

LED is a solid-state semiconductor component, which can directly convert electrical energy into lighting light. LED light source is called green light source. It has the characteristics of energy saving, environmental protection, durability, and small size. It is gradually replacing conventional lighting sources and becoming mainstream lighting. development trend. With the expansion of the LED industry, the lighting field is widely used, and the influence of the LED light source spectrum on the human eye has begun to attract attention. It is well known that the natural light spectrum is the most ideal light source, which gives people a comfortable feeling and is generally accepted by the public. The LED light source spectrum with a high degree of fitting has not yet come out. Existing technologies, such as: blue light chip + color-changing phosphor; blue light chip + red chip + yellow phosphor mixed to obtain white light, have many shortcomings such as discontinuous spectrum, low color rendering, poor light efficiency, complicated process and inconvenient industrialization. Thereby affecting the development of LED natural light spectrum light source.

Contents of the invention

The purpose of the present invention is to provide an LED flip-chip lighting device close to natural spectrum.

The LED flip-chip lighting device with a near-natural spectrum provided by the present invention has a schematic structural diagram as shown in Figure 1. The device includes an LED flip-chip 7, wherein a phosphor layer 8 and A transparent fluorescent ceramic layer 9 , and the phosphor layer 8 surrounds the LED flip chip 7 , and the transparent fluorescent ceramic layer 9 covers the upper surface of the phosphor layer 8 .

In the above device, the phosphor in the phosphor layer is (Y _{1-x Cex} ) ₃ (Al _1-y Cr _y ) ₅ O ₁₂ ;

In the (Y _1-x Ce _x ) ₃ (Al _1-y Cr _y ) ₅ O ₁₂ , 0≤x≤1 or x=0.02, 0≤y≤1 or y=0.008;

The emission peak of the fluorescent powder in the fluorescent powder layer is 680-750nm or 710nm.

The fluorescent powder can be prepared according to the following method: according to the molar ratio in the chemical formula (Y _{1-x Cex} ) ₃ (Al _1-y Cr _y ) ₅ O ₁₂ , the oxide powder corresponding to the raw material is weighed and proportioned, and after ball milling Mix evenly, coarsely grind after drying, heat up to the calcination temperature and then calcine, and cool down to room temperature after calcination;

In the above method, the time of ball milling is 8-20h;

In the heating and cooling steps, the heating rate and cooling rate are both 3-10°C/min or 5°C/min;

In the calcining step, the calcining temperature is 1400-1650°C; the calcining time is 3-6h or 4h.

The phosphor layer also contains an adhesive, specifically a silicone resin adhesive;

The phosphor powder in the phosphor powder layer accounts for 8-9.5% of the total mass of the phosphor powder and the adhesive.

The thickness of the phosphor layer is 0.05-0.12mm, specifically 0.0.9mm;

The material constituting the transparent fluorescent ceramic layer is Y ₃ Al ₅ O ₁₂ :Ce ³⁺ ; specifically, the material constituting the transparent fluorescent ceramic layer is Y ₃ Al ₅ O with a Ce ³⁺ doping concentration of 0.4%. ₁₂ : Ce ³⁺ ; the doping concentration refers to the mole percent concentration of Ce ³⁺ in Y ₃ Al ₅ O ₁₂ .

The transparent fluorescent ceramic layer can be sintered by mixing ceramic raw material powder and sintering aid; wherein, the ceramic raw material powder is specifically selected from Al ₂ O ₃ , Y ₂ O ₃ , MgAl ₂ O ₄ , MgAlON, AlN, At least one of SiN, ZrO ₂ and SiC; the sintering aid may be selected from at least one of CaO, MgO, TiO ₂ , SiO ₂ , MnO and kaolin.

Specifically, the transparent fluorescent ceramic sheet can be prepared according to the following method: mix the ceramic raw material powder and sintering aid in proportion, then add it to a ball milling tank, add ball milling media and ball milling balls for ball milling, and dry the obtained mixture , after grinding and sieving, carry out dry pressing and cold isostatic pressing to obtain the green body; then carry out vacuum sintering and isothermal pressing sintering on the obtained green body in turn, and then anneal;

Wherein, in the ball milling step, the ball milling speed is 235r/min, and the ball milling time is 10-24h;

In the drying step, the temperature is 50-120°C, and the time is 12h-48h;

In the sieving step, the mesh number of the sieve hole is 200-300 mesh;

In the dry pressing step, after weighing a certain mass and sieving, the powder is kept under pressure at 4Mpa-10Mpa for 3-10min;

In the cold isostatic pressing forming step, after dry pressing, put into a cold isostatic pressing machine at 200Mpa-300Mpa and hold the pressure for 1-10min;

In the vacuum sintering step, the sintering temperature is 1500-1800°C, the holding time is 5-30 hours, and the vacuum degree ^{is 10-1-10-4Pa ;}

In the isostatic pressing sintering step, the sintering temperature is 1600-1800°C, the holding time is 1-5 hours, and the pressure is 120-180MPa;

The annealing step is specifically to keep the temperature at 800-1500° C. for 5-40 hours, and then cool with the furnace.

The emission peak of the transparent fluorescent ceramic layer is 530-580nm, specifically 552nm.

The thickness of the transparent fluorescent ceramic layer is 0.15-0.3 mm, specifically 0.2 mm.

Specifically, the near-natural-spectrum LED flip-chip lighting device consists of a substrate 1, a circuit 2 located on the substrate 1, positive and negative electrodes 3 and 4, a dam 5, and several chip units 6;

The dam 5 surrounds all chip units 6;

The positive and negative electrodes 3 and 4 are respectively located on the substrate 1 in areas not surrounded by the dam 5;

Each chip unit 6 is connected to the circuit 2 through solder paste;

Each chip unit 6 consists of an LED flip chip 7, a phosphor layer 8 and a transparent fluorescent ceramic layer 9 from bottom to top, and the phosphor layer 8 surrounds the LED flip chip, and the transparent fluorescent ceramic layer 9 covering the upper surface of the phosphor layer 8;

A chip electrode 10 is provided at the bottom of the LED flip chip 7 , and the chip electrode 10 is connected to the circuit 2 .

The substrate 1 can specifically be an aluminum nitride substrate, an aluminum substrate, a copper substrate or an alumina substrate;

The emission wavelength of the LED flip chip 7 is 445nm-465nm, specifically 450-452.5nm;

The material constituting the positive and negative electrodes is silver or gold.

The color temperature of the near-natural spectrum LED flip-chip lighting device is 2700-6000K, specifically 4200K.

The method for preparing the above-mentioned near-natural spectrum LED flip-chip lighting device provided by the present invention comprises the following steps:

1) Printing a circuit 2 on the substrate 1;

2) Using solder paste to connect the chip electrode 10 on the LED flip chip 7 to the circuit 2, and then fix it;

3) After printing the phosphor layer 8 on the LED flip chip 7 and making the phosphor layer 8 surround the LED flip chip 7, the transparent fluorescent ceramic layer 9 is fixed on the phosphor layer 8 The surface, after curing, obtains a chip unit 6;

4) Repeat the steps 2) and 3) several times to obtain several chip units;

5) Paint dam glue on the periphery of all chip units 6 and bake, so that the obtained dams 5 surround all chip units 6, and obtain the LED flip-chip lighting device with a near-natural spectrum.

In the step 2) of the above method, in the connecting step, the connecting method is a crystal bonding method; in the fixing step, the fixing method is a reflow soldering method.

In the step 3) fixing step, the fixing method is crystal bonding.

The invention provides a near-spectrum LED flip-chip lighting device aiming at the near-natural spectrum requirements of lighting LEDs, which has good spectral continuity, high color rendering, and high luminous efficiency, and satisfies the needs of lighting LEDs well. , Conducive to promoting the rapid development of LED lighting.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the present invention, wherein; a is a top view of a near-natural spectrum LED flip-chip lighting device, b is a side view of a chip unit; 1 is an aluminum nitride substrate, 2 is a circuit, 3 and 4 are positive and negative electrodes , 5 is a dam, 6 is a chip unit, 7 is an LED flip chip, 8 is a phosphor layer, 9 is a transparent fluorescent ceramic layer, and 10 is a chip electrode;

Fig. 2 is a graph showing emission spectra of a conventional light source and a light source device obtained in Example 1 of the present invention at a color temperature of 4200K.

detailed description

The present invention will be further described below in conjunction with specific examples, but the present invention is not limited to the following examples. The methods are conventional methods unless otherwise specified. The raw materials can be obtained from open commercial channels unless otherwise specified. Unless otherwise specified, "%" in the examples means mass percentage. The silicone resin adhesive used in the following examples was purchased from Shin-Etsu Chemical Co., Ltd., Japan, with a product number of KER3000-M2.

The phosphor powder used in the following examples can be prepared according to the following method: according to the molar ratio in the chemical formula (Y _{1-x Cex} ) ₃ (Al _1-y Cr _y ) ₅ O ₁₂ , the raw material powder is weighed and proportioned, ball milled Mix evenly after 8 hours, coarsely grind after drying, heat up from room temperature to a calcination temperature of 1400°C at a rate of 5°C/min, then calcinate for 4 hours, and cool down to room temperature at a rate of 5°C/min after calcination;

The transparent fluorescent ceramic layer Y ₃ Al ₅ O ₁₂ : Ce ³⁺ can be prepared according to the following method: according to the molar ratio of each element in the chemical formula Y ₃ Al ₅ O ₁₂ : Ce ³⁺ , the corresponding oxide ceramic raw material powder After mixing in proportion, add it to the ball mill tank, add sintering aid CaO, ball milling medium and ball milling balls at the same time to mill at a speed of 235r/min for 10h, dry the resulting mixture at 120°C for 12h, grind it through a 200 mesh sieve, and keep it under 4Mpa After pressing for 10 minutes, put it into a cold isostatic press at ^300Mpa and keep the pressure for 5 minutes for cold isostatic pressing to obtain an embryo body; It is obtained by isothermally pressing and sintering for 5 hours (pressure is 120MPa), annealing at 800°C for 40 hours and cooling in the furnace.

Embodiment 1,

The LED flip-chip lighting device with a near-natural spectrum provided by the present invention has a schematic structural diagram as shown in Figure 1;

It consists of an aluminum nitride substrate 1, a circuit 2 located on the aluminum nitride substrate, positive and negative electrodes 3 and 4, a dam 5 and several chip units 6;

Dam 5 surrounds all chip units 6;

The positive and negative electrodes 3 and 4 are respectively located on the substrate 1 in areas not surrounded by the dam;

Each chip unit 6 is connected to the circuit through solder paste;

Each chip unit consists of an LED flip chip 7, a phosphor layer 8 and a transparent fluorescent ceramic layer 9 from bottom to top, and the phosphor layer surrounds the LED flip chip, and the transparent fluorescent ceramic layer 9 covers the phosphor layer 8 surface;

A chip electrode 10 is provided at the bottom of the LED flip chip, and the chip electrode is connected to the circuit through solder paste.

Among them, the phosphor layer 8 is composed of phosphor (Y _{1-x Cex} ) ₃ (Al _1-y Cr _y ) ₅ O ₁₂ (x is 0.02, y is 0.008) with an emission peak of 710nm and a silicone resin adhesive Composition, the mass percent concentration of phosphor powder in it is 8%; the thickness of this layer is 0.09mm;

The material constituting the transparent fluorescent ceramic layer 9 is a yellow material with an emission peak at 552 nm, that is, Y ₃ Al ₅ O ₁₂ :Ce ³⁺ with a Ce ³⁺ doping concentration of 0.4%; the thickness of this layer is 0.2 mm;

The material constituting the positive and negative electrodes is gold;

The LED flip chip 7 is a blue light chip, and the light emitting wavelength is 450-452.5nm.

The near-natural spectrum LED flip-chip lighting device can be prepared according to the following method:

1) Printing circuit 2 on substrate 1;

2) Using solder paste to connect the chip electrode 10 on the LED flip chip 7 to the circuit 2 by a die-bonding method, and then fix it by reflow soldering;

3) After printing the phosphor layer 8 on the LED flip chip 7 and making the phosphor layer 8 surround the LED flip chip 7, the transparent fluorescent ceramic layer 9 is fixed on the upper surface of the phosphor layer 8 by a crystal-bonding method, and after curing , get a chip unit 6;

4) Repeat steps 2) and 3) several times to obtain several chip units;

5) Draw dam glue on the periphery of all chip units 6 and bake, so that the obtained dams 5 surround all chip units 6, and obtain the near-natural spectrum LED flip-chip lighting device provided by the present invention.

Fig. 2 is a comparative emission spectrum diagram of a conventional light source and a light source device obtained in this embodiment at a color temperature of 4200K. It can be seen from the figure that the red spectrum of the light source obtained in the present invention is compensated, the spectrum continuity is good, the color rendering is high, and it is closer to the natural spectrum, which satisfies the healthy lighting requirements of lighting LEDs and is conducive to promoting the rapid development of LED high-quality lighting .

Claims (10)

1. A LED flip-chip lighting device near natural spectrum, comprising LED flip-chip, characterized in that: A phosphor layer and a transparent fluorescent ceramic layer are sequentially arranged on the flip chip, and the phosphor layer surrounds the LED flip chip, and the transparent fluorescent ceramic layer covers the upper surface of the phosphor layer. 2. The device according to claim 1, characterized in that: the phosphor powder of the phosphor layer is (Y _{1-x Cex} ) ₃ (Al _{1-y Cry} ) ₅ O ₁₂ ; In the (Y _1-x Ce _x ) ₃ (Al _1-y Cr _y ) ₅ O ₁₂ , 0≤x≤1 or x=0.02, 0≤y≤1 or y=0.008; The emission peak of the fluorescent powder in the fluorescent powder layer is 680-750nm or 710nm. 3. The device according to claim 1 or 2, characterized in that: the phosphor layer further contains an adhesive or a silicone resin adhesive; The phosphor powder in the phosphor powder layer accounts for 8-9.5% of the total mass of the phosphor powder and the adhesive. 4. The device according to any one of claims 1-3, characterized in that: the material constituting the transparent fluorescent ceramic layer is Y ₃ Al ₅ O ₁₂ :Ce ³⁺ ; or, The material constituting the transparent fluorescent ceramic layer is Y ₃ Al ₅ O ₁₂ :Ce ³⁺ with a Ce ³⁺ doping concentration of 0.4%; The emission peak of the transparent fluorescent ceramic layer is 530-580nm or 552nm. 5. The device according to any one of claims 1-4, characterized in that: the phosphor layer has a thickness of 0.05-0.12mm or 0.0.9mm; The thickness of the transparent fluorescent ceramic layer is 0.15-0.3mm or 0.2mm. 6. The device according to any one of claims 1-5, characterized in that: the near-natural spectrum LED flip-chip lighting device consists of a substrate and a circuit on the substrate, positive and negative electrodes, dams and several composed of chip units; The dam surrounds all chip units; The positive and negative electrodes are respectively located on the substrate in areas not surrounded by the dam; Each chip unit is connected to the circuit; Each chip unit consists of an LED flip chip, a phosphor layer and a transparent fluorescent ceramic layer from bottom to top, and the phosphor layer surrounds the LED flip chip, and the transparent fluorescent ceramic layer covers the phosphor the upper surface of the layer; A chip electrode is provided at the bottom of the LED flip chip, and the chip electrode is connected to the circuit. 7. The device according to claim 6, wherein the substrate is an aluminum nitride substrate, an aluminum substrate, a copper substrate or an alumina substrate; The emission wavelength of the LED flip chip is 445nm-465nm or 450-452.5nm; The material constituting the positive and negative electrodes is gold or silver. 8. The device according to any one of claims 1-7, characterized in that: the color temperature of the near-natural spectrum LED flip-chip lighting device is 2700-6000K or 4200K. 9. A method for preparing the near-natural spectrum LED flip-chip lighting device of any one of claims 1-8, comprising the steps of: 1) printing a circuit on the substrate; 2) after connecting the chip electrodes on the LED flip chip to the circuit, and then fixing them; 3) After printing a phosphor layer on the LED flip chip and making the phosphor layer surround the LED flip chip, fixing the transparent fluorescent ceramic layer on the upper surface of the phosphor layer, and after curing, the obtained a chip unit; 4) Repeat the steps 2) and 3) several times to obtain several chip units; 5) Draw dam glue on the periphery of all chip units and bake, so that the obtained dams surround all chip units, and obtain the LED flip-chip lighting device with a near-natural spectrum. 10. The method according to claim 9, characterized in that: in the step 2) connecting step, the method of connecting is crystal bonding; In the fixing step, the fixing method is reflow soldering; In the step 3) fixing step, the fixing method is crystal bonding.