WLED (White Light Emitting Diode) glue sealing method and device

Abstract

The invention discloses a WLED (White Light Emitting Diode) glue sealing method based on partitioned glue sealing. The sealing compound covers the LED chip and is filled in the LED bracket; carrying out subdivision on the sealing glue area, carrying out partitioning according to the exciting light energy density of the LED chip in the sealing glue area, dividing the area with relatively low energy density into a weak excitation area, dividing the area with relatively high energy density into a strong excitation area, and then carrying out sealing glue on the weak excitation area and the strong excitation area by using fluorescent powder glue step by step in sequence, respectively forming a weak excitation sealing compound and a strong excitation sealing compound; the fluorescent powder glue is prepared by mixing fluorescent powder glue and silica gel; the weak excitation sealing glue improves the consistency of spatial distribution under the combined action of centrifugal force and surface tension of fluorescent powder colloid; the strong excitation sealing compound improves the amplitude of the emitted spectrum and the luminous efficiency, and reduces the reabsorption of the fluorescent powder in the weak excitation sealing compound; the WLED device is applied to the WLED glue sealing method. The WLED applies purple light to excite fluorescent powder to emit green light and supplement light corresponding to the purple light and the green light, and two pairs of complementary light are synthesized into a white light spectrum; the color temperature of the WLED is improved by applying the cyan light, and the problems of low color temperature and high purple light radiation of the zero-blue-light WLED excited by the purple light are solved.

Description

Technical Field

[0001] The invention relates to the technical field of light sources, and in particular to a WLED sealing method and device. Background Art

[0002] WLED is white light LED. One-time sealing is the most mature technology for WLED packaging. Multiple sealing technologies can improve WLED performance, such as layered dispensing sealing technology. However, the spectral parameters of WLEDs packaged by existing multiple sealing technologies are highly discrete. The surface tension of the phosphor colloid itself is used to control the spatial distribution of the phosphor colloid, so that the phosphor colloid automatically forms a spatial distribution form, which improves the consistency of the phosphor distribution and thus improves the consistency of the spectral parameters of the packaged WLED.

[0003] Blue light is an indispensable spectrum for human health, but WLEDs rich in blue light pose a risk of harming human vision and physiological rhythms, so zero-blue-light WLEDs with extremely low blue-light spectrum energy are more photobiologically safe; it is reported that the inventor of the Nobel Prize-winning high-efficiency LED blue-light chip first invented a zero-blue-light WLED with a color temperature of about 2700K, which has excellent healthy light source properties, but its high-amplitude purple light spectrum produces a serious white glare phenomenon, and thus does not have the properties of a general lighting source. The color temperature range of the general lighting white light spectrum is 2700-5000K, and the color temperature of WLEDs decreases as the blue light spectrum energy decreases. The low color temperature of the existing zero-blue-light WLED is another important problem that does not have the properties of a general lighting source.

[0004] Zero blue spectrum WLED is an optimization solution for zero blue light WLED. Zero blue spectrum WLED reduces the blue light spectrum energy in a specific wavelength band to near zero, such as blue light in the 440-460nm wavelength band, based on the weighted function of blue light damage to the human eye retina and the melatonin inhibition spectrum characteristics. Zero blue spectrum WLED not only reduces the blue light spectrum energy in a specific wavelength band with a higher risk of damage, but also has a higher color temperature, and has the dual attributes of a healthy light source and a general lighting source.

[0005] A WLED sealing method and device overcome the above-mentioned shortcomings. Summary of the invention

[0006] The purpose of the present invention is to provide a WLED sealing method and device, which performs zone sealing, divides weak excitation areas and strong excitation areas, and seals with phosphor glue in sequence and step by step; a WLED device using a WLED sealing method overcomes the technical problem that the WLED emission spectrum has a low color temperature due to low blue light energy.

[0007] The technical solution for achieving the purpose of the present invention is:

[0008] A WLED sealing method comprises partitioned sealing; the sealing glue covers the LED chip and fills the LED bracket, the sealing glue area is subdivided into a weak excitation area and a strong excitation area, according to the energy density of the LED chip excitation light in the sealing glue area, the area with relatively low energy density is divided into the weak excitation area, and the area with relatively high energy density is divided into the strong excitation area, the weak excitation area and the strong excitation area are sealed with fluorescent powder glue in sequence, forming weak excitation sealing glue and strong excitation sealing glue respectively, and the fluorescent powder glue is prepared by mixing fluorescent powder and silica gel.

[0009] A preferred solution is that the weak excitation area sealing comprises the following steps:

[0010] 1) Spray the phosphor glue to cover the LED chip, or spray it evenly at multiple points around the LED chip;

[0011] 2) Fixing the product of step 1) on the fixture of the centrifuge, setting the speed of the centrifuge, and transporting the phosphor glue to the weak excitation area by centrifugal force. Under the combined effect of centrifugal force and surface tension of the phosphor glue, the phosphor glue is automatically distributed in the weak excitation area to form a weak excitation sealant;

[0012] 3) Dynamic pre-curing: set the centrifuge speed and working chamber temperature to dynamically pre-cure the phosphor glue.

[0013] A preferred solution is that the strong excitation area sealing comprises the following steps:

[0014] Spraying phosphor glue, the phosphor glue covers the LED chip and the pre-cured weak excitation sealing glue;

[0015] Fix the product of step 1) on the fixture of the centrifuge, set the speed of the centrifuge, and use centrifugal force to make the phosphor glue level in the strong excitation area to form a strong excitation sealing glue;

[0016] High temperature curing is performed according to the existing conventional method, including curing of weak excitation sealing glue and strong excitation sealing glue.

[0017] Another technical solution of the present invention is:

[0018] A WLED device comprises an LED bracket, an LED chip and a sealing glue; the sealing glue is applied to the WLED sealing glue method.

[0019] The LED chip emits purple light, and the sealing glue contains cyan phosphor, yellow phosphor, red phosphor, and silica gel; the purple light excites the cyan phosphor, yellow phosphor, and red phosphor to emit cyan light, yellow light, and red light respectively; the purple light and yellow light complement each other, and the cyan light and red light complement each other, and the two pairs of complementary lights synthesize the WLED spectrum.

[0020] A preferred solution is that the wavelengths of the purple light and the yellow light, the cyan light and the red light are calculated by the following relationship:

[0021] λ1=565.5+233.0 / (497.8-λ2)

[0022] Wherein λ1 is the wavelength value of the yellow light or red light, and λ2 is the wavelength value of the purple light or cyan light.

[0023] A preferred solution is that the main wavelength of the emission spectrum of the weak excitation sealant is not less than the main wavelength of the emission spectrum of the strong excitation sealant.

[0024] A preferred solution is that the relative spectrum amplitude of the blue light emitted by the WLED in the wavelength range of 440-460nm is not greater than 0.05, and the color temperature value is not less than 2700K.

[0025] A preferred solution is that the relative spectral amplitude of the cyan light is not less than 0.5.

[0026] The beneficial effects of the present invention are as follows: the weak excitation sealant improves the consistency of the spatial distribution morphology of the fluorescent powder colloid and reduces the discreteness of the WLED emission spectrum parameters; the strong excitation sealant improves the amplitude of the emitted spectrum and the light output efficiency, and reduces the reabsorption of the emitted spectrum of the strong excitation sealant by the fluorescent powder in the strong excitation sealant; the blue light spectrum energy in the wavelength band with higher risk of damage is reduced, and it has a higher color temperature, and has the dual attributes of a healthy light source and a general lighting light source. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A cross-sectional view of the WLED sealing area in the present invention;

[0028] Figure 2 A cross-sectional view of the WLED weak excitation sealant in the present invention;

[0029] Figure 3 A cross-sectional view of the WLED sealing glue of the present invention;

[0030] Figure 4 A schematic diagram of the spectrum composition of a WLED device of the present invention;

[0031] Figure 5 The zero blue spectrum WLED device emission spectrum of the present invention;

[0032] Figure 6 Spectral test of zero blue spectrum WLED device. DETAILED DESCRIPTION

[0033] To illustrate the concept and purpose of the present invention, the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0034] A WLED sealing method;

[0035] Figure 1 As shown, the sealing glue covers the LED chip 2 and fills the LED bracket 1;

[0036] The sealing area is subdivided into a weak excitation area 31 and a strong excitation area 32; according to the energy density of the excitation light 21 of the LED chip 2, the area with relatively low energy density is divided into the weak excitation area 31, and the area with relatively high energy density is divided into the strong excitation area 32;

[0037] The weak excitation region 31 is sealed with a phosphor glue 312 to form a weak excitation sealing glue 311;

[0038] Figure 2 As shown, the sealing method of the weak excitation area 31 includes the following steps:

[0039] 1) Spray the phosphor glue to cover the LED chip, or spray it evenly at multiple points around the LED chip;

[0040] 2) Fix the product of step 1) on the fixture of the centrifuge, set the centrifuge speed to 800 rpm, the time to 3 minutes, and the temperature to transport the phosphor glue to the weak excitation area by centrifugal force, and at the same time, under the action of the surface tension of the phosphor glue, the phosphor glue 312 is automatically distributed in the weak excitation area to form a weak excitation sealant 311;

[0041] 3) Dynamic pre-curing: set the centrifuge speed to 100 rpm, the working chamber temperature to 100 degrees Celsius, and the time to 10 minutes to dynamically pre-cure the phosphor glue.

[0042] Figure 3 As shown, the strong excitation area 32 is sealed with phosphor glue to form a strong excitation sealing glue 312;

[0043] The method for sealing the strong excitation area 32 comprises the following steps:

[0044] 1) Spraying phosphor glue to cover the LED chip 2 and the pre-cured weak excitation sealant 311;

[0045] 2) Fix the product of step 1) on the fixture of the centrifuge, set the centrifuge speed to 600 rpm, the time to 2 minutes, and the temperature to make the phosphor glue level in the strong excitation area by centrifugal force to form a strong excitation sealing glue 312;

[0046] 3) Performing high temperature curing according to the conventional high temperature baking method, including curing the weak excitation sealant and the strong excitation sealant.

[0047] The weak excitation sealant and the strong excitation sealant are cured by high temperature baking in a constant temperature box.

[0048] The weak excitation sealant improves the consistency of the spatial distribution morphology of the phosphor colloid and reduces the discreteness of the WLED emission spectrum parameters; the strong excitation sealant improves the amplitude of the emitted spectrum and the light output efficiency, and reduces the reabsorption of the emitted spectrum of the strong excitation sealant by the phosphor in the weak excitation sealant; it reduces the blue light spectrum energy in the wavelength band with higher risk of damage, and has a higher color temperature, and has the dual attributes of a healthy light source and a general lighting source.

[0049] A WLED device comprises an LED bracket, an LED chip and a sealing glue; the sealing glue applies the WLED sealing glue method.

[0050] like Figures 1 to 5 As shown, the LED chip emits purple light, and the encapsulant contains cyan phosphor, yellow phosphor and red phosphor; the purple light excites the cyan phosphor, yellow phosphor and red phosphor to emit cyan light, yellow light and red light respectively; the purple light and yellow light complement each other, and the cyan light and red light complement each other, and the two pairs of complementary lights synthesize the WLED spectrum.

[0051] like Figures 1 to 5 As shown, the wavelengths of the purple light and the yellow light, the cyan light and the red light are calculated by the following relationship:

[0052] λ1=565.5+233.0 / (497.8-λ2)

[0053] Wherein λ1 is the wavelength value of the yellow light or red light, and λ2 is the wavelength value of the purple light or cyan light.

[0054] like Figures 1 to 5 As shown, the main wavelength of the emission spectrum of the weak excitation sealant is not less than the main wavelength of the emission spectrum of the strong excitation sealant.

[0055] like Figures 1 to 5 As shown, the relative spectrum amplitude of the blue light emitted by the WLED in the wavelength range of 440-460nm is not greater than 0.05, and the color temperature value is not less than 2700K.

[0056] like Figures 1 to 5 As shown, the relative spectral amplitude of the cyan light is not less than 0.5.

[0057] like Figures 1 to 5 As shown, a WLED device;

[0058] The peak wavelength of the purple light emitted by the LED chip is selected to be 411.5nm;

[0059] Yellow light wavelength calculation: λy=565.5+233.0 / (497.8-411.5)=568.2

[0060] The wavelength of cyan light was selected as 494nm;

[0061] Calculation of red light wavelength: λr=565.5+233.0 / (497.8-494)=626.8

[0062] Select cyan phosphor with luminescence wavelength of 494nm:

[0063] The cyan phosphor is preferably BN488, a silicon-based oxynitride material, with a main wavelength of 497.3±0.2nm, a peak wavelength of 493.9±1nm, and a half-peak width of 32.2±0.5nm;

[0064] Select yellow phosphor with a luminous wavelength of 568.2nm:

[0065] The yellow phosphor is preferably BRVY66, made of rare earth silicate material, with a main wavelength of 565.4±0.2nm, a peak wavelength of 549.3±1nm, and a half-peak width of 86.1±0.5nm;

[0066] Select red phosphor with a luminous wavelength of 626.8nm:

[0067] The red phosphor is preferably of BRD630G5 specification, silicon-based nitride material, with a main wavelength of 606.2±0.2nm, a peak wavelength of 626.7±1nm, and a half-peak width of 74.9±0.5nm;

[0068] The phosphor glue is mixed in the following weight ratios: 1.1656 cyan phosphor, 0.6486 yellow phosphor, 0.18236 red phosphor, 1.0 A silica gel, 10.0 B silica gel;

[0069] Figure 4 As shown, a spectrum of a WLED device is formed, purple light 1 and yellow light 3 are complementary lights, cyan light 2 and red light 4 are complementary lights, and two pairs of complementary lights are combined into a WLED spectrum;

[0070] The weak excitation sealant is a red phosphor sealant, and the strong excitation sealant is a cyan phosphor and a yellow phosphor sealant; the emission spectrum of the weak excitation sealant is the emission spectrum of the red phosphor, and its main wavelength is 606.2nm, and the emission spectrum of the strong excitation sealant is the main wavelength of the emission spectrum of the cyan and yellow phosphors, and its main wavelengths are 497.3nm and 565.4nm, that is, the main wavelength of the emission spectrum of the weak excitation sealant is not less than the main wavelength of the emission spectrum of the strong excitation sealant;

[0071] Applying the WLED encapsulation method, the WLED device is encapsulated into a zero blue spectrum WLED device whose blue light spectrum energy in the wavelength range of 440-460nm is reduced to near zero;

[0072] Figure 5 As shown, the emission spectrum of the zero blue spectrum WLED device;

[0073] The blue light relative spectrum amplitude of the WLED emission spectrum in the wavelength range of 440-460nm is not greater than 0.05, and the color temperature value is not less than 2700K.

[0074] The zero blue spectrum WLED device emits a spectrum with a cyan light peak wavelength of 492.7 nm and a relative spectrum amplitude greater than 0.5, reaching 0.63.

[0075] Figure 6 As shown, the spectrum test of zero blue spectrum WLED device;

[0076] The color temperature value is 3650K.

Claims

1. A WLED sealing method, characterized in that: Partitioned sealing glue; the sealing glue covers the LED chip and fills the LED bracket, and the area of ​​the sealing glue is subdivided into a weak excitation area and a strong excitation area. According to the energy density of the excitation light of the LED chip in the area of ​​the sealing glue, the area with relatively low energy density is divided into a weak excitation area, and the area with relatively high energy density is divided into a strong excitation area. The weak excitation area and the strong excitation area are sealed with fluorescent powder glue in steps to form weak excitation sealing glue and strong excitation sealing glue respectively; the fluorescent powder glue is prepared by mixing fluorescent powder and silica gel.

2. A WLED sealing method according to claim 1, characterized in that: The weak excitation area sealing comprises the following steps: 1) Spray the phosphor glue to cover the LED chip, or spray it evenly at multiple points around the LED chip; 2) Fixing the product of step 1) on the fixture of the centrifuge, setting the speed of the centrifuge, and transporting the phosphor glue to the weak excitation area by centrifugal force. Under the combined effect of centrifugal force and surface tension of the phosphor glue, the phosphor glue is automatically distributed in the weak excitation area to form a weak excitation sealant; 3) Dynamic pre-curing: set the centrifuge speed and working chamber temperature to dynamically pre-cure the phosphor glue.

3. A WLED sealing method according to claim 2, characterized in that: The strong excitation area sealing comprises the following steps: 1) Spraying phosphor glue, the phosphor glue covers the LED chip and the pre-cured weak excitation sealing glue; 2) Fix the product of step 1) on the fixture of the centrifuge, set the speed of the centrifuge, and use centrifugal force to make the phosphor glue level in the strong excitation area to form a strong excitation sealing glue; 3) Performing high temperature curing according to the conventional high temperature baking method, including curing the weak excitation sealant and the strong excitation sealant.

4. A WLED device, characterized in that: It comprises an LED bracket, an LED chip and a sealing glue; the sealing glue is applied by a WLED sealing glue method as described in claims 1 to 4.

5. A WLED device according to claim 4, characterized in that: The LED chip emits purple light, and the sealing glue contains cyan phosphor, yellow phosphor, red phosphor and silica gel; the purple light excites the cyan phosphor, yellow phosphor and red phosphor to emit cyan light, yellow light and red light respectively; the purple light and yellow light complement each other, and the cyan light and red light complement each other, and the two pairs of complementary lights synthesize the WLED spectrum.

6. A WLED device according to claim 4, characterized in that: The wavelengths of the purple light, yellow light, blue light and red light are calculated by the following relationship: λ1=565.5+233.0 / (497.8-λ2) Wherein λ1 is the wavelength value of the yellow light or red light, and λ2 is the wavelength value of the purple light or cyan light.

7. The WLED device according to claim 4, characterized in that: The main wavelength of the emission spectrum of the weak excitation sealant is not less than the main wavelength of the emission spectrum of the strong excitation sealant.

8. The WLED device according to claim 4, characterized in that: The blue light relative spectrum amplitude of the WLED emission spectrum in the wavelength range of 440-460nm is not greater than 0.05, and the color temperature value is not less than 2700K.

9. The WLED device according to claim 4, characterized in that: The relative spectral amplitude of the cyan light is not less than 0.5.

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