A white light source for controlling the coordinate deviation of fluorescent powder

Abstract

A kind of white light source of controlling fluorescent powder coordinate deviation, including fluorescent powder and the blue light chip of exciting fluorescent powder;The fluorescent powder includes lutetium powder, gallium powder and red powder, the peak wavelength of the lutetium powder is 530-540nm, the peak wavelength of the gallium powder is 540-550nm, gallium content 15-25% of gallium powder, the red powder is nitride red powder, and the peak wavelength of red powder is 618-630nm.The principle of the present application is as follows: according to the coordinate deviation of chip XY, wavelength shift and the coordinate deviation rule of different types of fluorescent powder, based on specific chip wave band, fluorescent powder type is matched and combined, within a certain current variation range, the control of fluorescent powder coordinate deviation is realized;The original YAG yellow powder is replaced by high-wave gallium powder, which can fill the yellow light spectrum and solve the problem of large CIE XY coordinate deviation of yellow powder.

Description

Technical Field

[0001] This invention relates to the field of LEDs, and in particular to a white light source for controlling the coordinate offset of phosphors. Background Technology

[0002] In dimming and color-tuning product applications, the excitation of phosphors by blue light from the chip is affected by current and thermal stability, which can cause the emitted color temperature to drift beyond product requirements after packaging, affecting the subjective effect on the human eye. Conventional white light sources use a combination of lutetium phosphor with a peak wavelength of 534nm, yellow phosphor with a peak wavelength of 555nm, and red phosphor. This type of phosphor exhibits a large coordinate shift after excitation. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a white light source for controlling the coordinate offset of phosphors, so that the coordinate offset of the phosphors after excitation is small.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is: a white light source for controlling phosphor coordinate offset, comprising phosphor and a blue light chip for exciting the phosphor; the phosphor includes lutetium powder, gallium powder, and red phosphor, wherein the peak wavelength of the lutetium powder is 530-540nm, the peak wavelength of the gallium powder is 540-550nm, the gallium content of the gallium powder is 15-25%, and the red phosphor is nitride red phosphor with a peak wavelength of 618-630nm. The principle of the invention: based on the XY coordinates of the chip, wavelength offset, and the coordinate offset patterns of different types of phosphors, and based on a specific chip wavelength band, phosphor types are combined to control the phosphor coordinate offset within a certain current variation range; using high-wavelength gallium powder to replace the original YAG yellow phosphor fills the yellow light band spectrum while solving the problem of large CIE XY coordinate offset of the yellow phosphor.

[0005] As an improvement, the peak wavelength of the lutetium powder is 534 nm, the peak wavelength of the gallium powder is 547 nm, and the gallium content of the gallium powder is 20%.

[0006] As an improvement, the lutetium powder and gallium powder are mixed in a 1:1 ratio.

[0007] As an improvement, the lutetium powder, gallium powder, red powder, and phenyl silica gel are combined to form a fluorescent adhesive.

[0008] As an improvement, the phosphor is composed of lutetium powder with a peak wavelength of 534 nm, gallium powder with a peak wavelength of 547 nm and a gallium content of 20%, and red nitride powder.

[0009] As an improvement, the gallium powder contains 70-80% yttrium, 15-25% gallium, 2.5-3.5% cerium, 2.0-2.5% barium, 0.1-0.2% strontium, and 0.1-0.15% zinc.

[0010] As an improvement, the main wavelength of the blue light chip is 452.5-455nm.

[0011] The beneficial effects of this invention compared to the prior art are:

[0012] Based on the XY coordinates of the wafer, wavelength offset, and coordinate offset patterns of different types of phosphors, phosphor types are combined and matched according to specific wafer wavelengths to control the phosphor coordinate offset within a certain range of current variation. High-wavelength gallium phosphor is used to replace the original YAG yellow phosphor, which can fill the yellow light band spectrum and solve the problem of large CIE XY coordinate offset of yellow phosphor. Attached Figure Description

[0013] Figure 1 A comparison chart of coordinate offsets for finished products of different types of phosphors. Detailed Implementation

[0014] The present invention will now be further described with reference to the accompanying drawings.

[0015] A white light source for controlling phosphor coordinate offset includes phosphor and a blue light chip for exciting the phosphor.

[0016] The phosphor is composed of lutetium powder, gallium powder, and red phosphor. The peak wavelength of the lutetium powder is 530-540 nm, the peak wavelength of the gallium powder is 540-550 nm, and the gallium content of the gallium powder is 15-25%. The red phosphor is a nitride red phosphor with a peak wavelength of 618-630 nm. In a preferred embodiment, the peak wavelength of the lutetium powder is 534 nm, the peak wavelength of the gallium powder is 547 nm, the gallium content of the gallium powder is approximately 20%, and the peak wavelength of the red phosphor is 622 nm.

[0017] The white light source of this invention is encapsulated with fluorescent adhesive. The fluorescent adhesive is formed by combining lutetium powder, gallium powder, red powder and phenyl silica gel. The lutetium powder and gallium powder are mixed in a 1:1 ratio, specifically: 1.0% red powder, 7.4% gallium powder, 7.3% lutetium powder and 84.4% phenyl silica gel.

[0018] The peak wavelength of the blue light chip is 452.5-455nm.

[0019] The gallium powder contains 70-80% yttrium, 15-25% gallium, 2.5-3.5% cerium, 2.0-2.5% barium, 0.1-0.2% strontium, and 0.1-0.15% zinc.

[0020] Table 1. XY coordinates and peak wavelength Wp shift of the bare die under different currents.

[0021]

[0022]

[0023] Based on the test results in Table 1 above, the following are observed: Different operating currents of the wafers will cause changes in the CIE coordinates and wavelength; increasing the current increases the X-coordinate and decreases the Y-coordinate; increasing the current decreases the peak wavelength Wp; the offset of high-wavelength wafers (447.5-460nm) is greater than that of low-wavelength wafers (447.5-455nm). Therefore, this invention selects a blue LED wafer with a main wavelength of 452.5-455nm.

[0024] Table 2. Coordinate shift of phosphor as a function of current (minus the effect of wafer offset)

[0025]

[0026]

[0027] Based on the test results in Table 2 above, the coordinate shifts of different lutetium powders are stable, with similar trends: X remains basically unchanged, while Y increases by approximately 0.002. For high-wave gallium powder (containing 20.0% gallium), the coordinates show a decrease of 0.002 in X and an increase of 0.004 in Y. YAG yellow powder exhibits the largest decrease in X and Y coordinates, with X decreasing by 0.006 and Y decreasing by 0.008. For nitride red powder, the coordinates show a decrease of 0.0014 in X and an increase of 0.0005 in Y. In summary, the coordinates of lutetium powder and nitride red powder are relatively stable, while the coordinate shifts of low-wave gallium powder and YAG yellow powder are large.

[0028] Table 3 Comparison of coordinate offsets for the same powder, different wavelengths, and different currents.

[0029]

[0030]

[0031] According to the test results in Table 3 above, the powder coordinate shift trend is different when the wafer is excited at different wavelengths.

[0032] Table 4 Comparison of coordinate offsets of finished products of different types of phosphors

[0033]

[0034] Comparison conclusions: such as Figure 1As shown, in combination ①-③ (LU-YAG + YAG yellow + nitride scheme), both X and Y coordinates decrease, with Y decreasing by more than -0.007, indicating that both lutetium powder and yellow powder cause the coordinates to be too low. In combination ④ (GA-YAG + nitride), both coordinates increase, with Y increasing slightly more, indicating that gallium powder causes the coordinates to be too high. In combination ⑤ (LU-YAG + GA-YAG + nitride), the increase in X and Y is less than in combination ④, indicating that the combination of gallium powder and lutetium powder can reduce the coordinate offset. In combination ⑥, the phosphor scheme of this invention (LU-YAG + GA-YAG + nitride), the change in X and Y is <0.001, indicating that the combination of high-wavelength gallium powder and lutetium powder is more suitable than the combination of low-wavelength lutetium powder, while also compensating for the yellow light band spectrum.

[0035] The principle of this invention is as follows: Based on the XY coordinates of the wafer, wavelength offset, and coordinate offset patterns of different types of phosphors, and using a combination of phosphor types within a specific wafer wavelength band, the phosphor coordinate offset can be controlled within a certain range of current variation. By using high-wavelength gallium phosphor to replace the original YAG yellow phosphor, the problem of large CIE XY coordinate offset of yellow phosphor can be solved while filling the yellow light band spectrum.

Claims

1. A white light source for controlling phosphor coordinate offset, comprising phosphor and a blue light-emitting wafer for exciting the phosphor; characterized in that: The phosphor includes lutetium powder, gallium powder, and red phosphor. The peak wavelength of the lutetium powder is 530-540 nm, the peak wavelength of the gallium powder is 540-550 nm, the gallium content of the gallium powder is 15-25%, and the red phosphor is a nitride red phosphor with a peak wavelength of 618-630 nm.

2. A white light source for controlling phosphor coordinate offset according to claim 1, characterized in that: The peak wavelength of the lutetium powder is 534 nm, the peak wavelength of the gallium powder is 547 nm, and the gallium content of the gallium powder is 20%.

3. A white light source for controlling phosphor coordinate offset according to claim 1, characterized in that: The lutetium powder and gallium powder are mixed in a 1:1 ratio.

4. A white light source for controlling phosphor coordinate offset according to claim 1, characterized in that: The lutetium powder, gallium powder, red powder, and phenyl silica gel are combined to form a fluorescent adhesive.

5. A white light source for controlling phosphor coordinate offset according to claim 1, characterized in that: The phosphor is composed of lutetium powder with a peak wavelength of 534 nm, gallium powder with a peak wavelength of 547 nm and a gallium content of 20%, and red nitride powder.

6. A white light source for controlling phosphor coordinate offset according to claim 1, characterized in that: The gallium powder contains 70-80% yttrium, 15-25% gallium, 2.5-3.5% cerium, 2.0-2.5% barium, 0.1-0.2% strontium, and 0.1-0.15% zinc.

7. A white light source for controlling phosphor coordinate offset according to claim 1, characterized in that: The main wavelength of the blue light chip is 452.5-455nm.

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