Annealing method of cerium-doped yttrium aluminium garnet wafer for white-light LED (Light Emitting Diode)

A technology doped with yttrium aluminum garnet and cerium, which is applied in the field of LED fluorescent materials, can solve problems such as easy aging, poor particle size and dispersion uniformity, and uneven coating, so as to improve transmittance, eliminate oxygen vacancies, Wide range of effects

Active Publication Date: 2014-02-19
WENZHOU UNIVERSITY
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, at this stage, phosphors for white LEDs have the following outstanding problems: low excitation efficiency and light conversion efficiency; poor particle size and dispersion uniformity, uneven coating, and unsatisfactory color uniformity; large light attenuation, which seriously affects the use of white LEDs Lifespan; poor physical and chemical properties, low thermal conductivity, unstable under high temperature conditions, easy to age, not suitable for the development needs of high-power LEDs
Patent CN101545143A uses high-temperature hydrogen annealing and low-temperature oxygen annealing respectively for Ce:YAG crystals grown by graphite heating method, so that the luminous efficiency of Ce:YAG crystals is greatly improved, but it has several disadvantages: (1) crystal The growth method is single, only for the graphite heating method; (2) The annealing treatment of oxygen and hydrogen is only used, and the advantages of the two are not considered; (3) The purpose of annealing is single, only focusing on the crystal transmittance and The intensity of the fluorescence spectrum does not consider the broader application prospects of Ce:YAG crystals

Method used

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  • Annealing method of cerium-doped yttrium aluminium garnet wafer for white-light LED (Light Emitting Diode)

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] According to the stoichiometric formula (Y 1-x Ce x ) 3 (Al 1-y Ga y ) 5 o 12 (x=0.04 / 3, y=0) Weigh Y with purity ≥99.99% 2 o 3 、Al 2 o 3 , CeO 2 Raw materials, ground and mixed evenly, briquetted, pre-fired at 1200°C for 24 hours, then transferred to the intermediate frequency induction single crystal furnace together with the seed crystal, and the sealed system was vacuumed to 10 -4 P a , when the furnace temperature reaches 1400°C, nitrogen with a purity greater than 99% is introduced, and the temperature continues to rise to 1900°C in this atmosphere, and the temperature is kept for 2 hours. By adjusting the temperature of the furnace until the raw materials are melted, after inoculation, shouldering, equal diameter, and finishing Waiting for the process to pull and grow Y 2.96 Al 5 o 12 : Ce 0.04 crystals. The crystal growth direction is the direction. After the growth is over, slowly cool down to room temperature at a rate of 25°C / h, and the Y 2....

Embodiment 2

[0029] With the 4mm*4mm*0.5mmY obtained according to the method of embodiment 1 2.96 Al 5 o 12 : Ce 0.04 After the wafer is polished, it is sent into the tubular annealing furnace, and after vacuuming, the O 2 , adjust the pressure in the furnace to 0.05MPa, rise from room temperature at 120°C / h to 300°C and keep it for 3 hours, then raise it at 150°C / h to 900°C and keep it for 3 hours, and finally rise to 1500°C at 100°C / h, 3 After heating up, keep 1500°C for 24 hours, then cool down to 1100°C at a rate of 50°C / h, cool to 900°C at a rate of 100°C / h, and drop to room temperature at a rate of 200°C / h to obtain the annealed Y 2.96 Al 5 o 12 : Ce 0.04 Chip, this chip can be used to package high-performance white light LED.

Embodiment 3

[0031] According to the stoichiometric formula (Y 1-x Ce x ) 3 (Al 1-y Ga y ) 5 o 12 (x=0.03 / 3, y=0) Weigh Y with purity ≥99.99% 2 o 3 、Al 2 o 3 , CeO 2 Raw materials, ground and mixed evenly, briquetted, pre-fired at 1200°C for 12 hours, then transferred to the intermediate frequency induction single crystal furnace together with the seed crystal, and the sealed system was vacuumed to 10 -4 Pa, when the furnace temperature reaches 1400°C, nitrogen with a purity greater than 99% is introduced, and the temperature continues to rise to 1850°C in this atmosphere, and the temperature is kept for 2 hours. By adjusting the temperature of the furnace until the raw materials melt, and then through inoculation, shouldering, equal diameter, Finishing and other processes to lift and grow Y 2.97 Al 5 o 12 : Ce 0.03 crystals. The crystal growth direction is the direction. After the growth is over, slowly cool down to room temperature at a rate of 20°C / h, and the Y 2.97 Al ...

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Abstract

The invention discloses an annealing method of a cerium-doped yttrium aluminium garnet wafer for a white-light LED (Light Emitting Diode). The annealing method comprises the following steps: (1) putting the cerium-doped yttrium aluminium garnet wafer in a porcelain boat, feeding the porcelain boat into a tubular annealing furnace, introducing annealing atmosphere and sealing, wherein the annealing atmosphere is a mixed gas A or oxygen, the mixed gas A is iH2+kL, the L stands for an inert protective gas, the i and the k respectively stand for the volume parts of the H2 and the L in the mixed gas A, and i / i+k is greater than or equal to 25% and less than or equal to 75%; (2) heating to 300 DEG C from a room temperature at the rate of 100-150 DEG C / h, and carrying out heat preservation for 3-8 hours; then heating to 900 DEG C at the rate of 150-200 DEG C / h, and carrying out heat preservation for 3-8 hours; heating to 1100-1500 DEG C at the rate of 100-150 DEG C / h, and annealing at a constant temperature for 30-72 hours; after annealing, cooling to 1100 DEG C at the rate of no greater than 50 DEG C / h, then cooling to 900 DEG C at the rate of 100 DEG C / h, finally cooling to a room temperature at the rate of 150-200 DEG C, wherein the time required in the total cooling stage is about 6.5-1.6 hours, and taking out so as to obtain the annealed wafer.

Description

【Technical field】 [0001] The invention relates to an annealing method for a cerium-doped yttrium aluminum garnet wafer used for white light LEDs, and belongs to the technical field of LED fluorescent materials. 【Background technique】 [0002] LED is recognized as "green lighting" in the 21st century. In the preparation of white light LEDs, the performance of fluorescent materials directly affects the luminous efficiency, conversion efficiency, color coordinates, color temperature and color rendering of white light LEDs. At present, the white light LED fluorescent material is mainly composed of amorphous phosphor powder, and the commercialized white light LED product is based on the combination of blue light chip and phosphor powder to form white light. However, at this stage, phosphors for white LEDs have the following outstanding problems: low excitation efficiency and light conversion efficiency; poor particle size and dispersion uniformity, uneven coating, and unsatisfac...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B33/02C30B29/28
Inventor 向卫东赵斌宇陈兆平梁晓娟张志敏刘丙峰
Owner WENZHOU UNIVERSITY
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