Module Structure of a Multi - primary - color LED Light Source

Abstract

The present invention discloses a module structure for achieving light mixing and light extraction from a multi-primary color LED light source, comprising a plurality of LED lamp beads, a second thermal interface layer, a secondary optical lens, a second substrate layer, and a sealing ring. The LED lamp beads include a plurality of LED chips with different dominant wavelengths, leads, a primary optical lens, a first thermal interface layer, and a first substrate layer, with the chips of different dominant wavelengths arranged in an interlaced manner. The primary optical lens seals the plurality of LED chips on the first substrate layer; the plurality of LED lamp beads are respectively fixed to the second substrate layer via a second thermal interface layer material layer, and the secondary optical lens is mounted on the second substrate layer; the plurality of LED lamp beads are mounted at different angles on the second substrate layer; and a third encapsulation colloid layer is included between the primary optical lens and the secondary optical lens. Through this module structure, the present invention solves the problem of poor spatial color uniformity in the light output of a multi-primary color LED light source while simultaneously improving its light extraction efficiency.

Description

Technical Field

[0001] The present invention relates to semiconductor lighting technology, and in particular to a module structure of a multi-primary color LED light source. Background Art

[0002] LEDs (Light Emitting Diodes) are semiconductor light-emitting devices based on the principle of PN junction electroluminescence. They offer high electro-optical conversion efficiency, long life, environmental friendliness, energy savings, and compact size. They are hailed as the green lighting source of the 21st century. Their application in traditional lighting applications promises significant energy savings, a crucial advantage in today's increasingly energy-scarce world. The LED manufacturing industry chain primarily encompasses four key links: epitaxial growth, chip fabrication, packaging, and application. The packaging and application stages are crucial for transitioning from upstream chips to applications, fulfilling key functions such as mechanical protection, electrical signal connection, optical parameter control, and heat dissipation. The quality of these stages directly determines the ultimate optical performance and reliability of LED products.

[0003] Currently, traditional white LEDs, consisting of a blue chip combined with yellow phosphor, suffer from excessive blue light, a lack of cyan light, and insufficient red light. A growing number of studies have shown that white LEDs using this method pose a significant risk of blue light hazards. The large proportion of blue light power can adversely affect the user's biorhythm, specifically suppressing melatonin secretion, disrupting the circadian rhythm, and leading to sleep disorders. Furthermore, due to photon energy loss during the conversion from short-wavelength to long-wavelength, the conversion efficiency of yellow phosphors is difficult to achieve 100% (typically around 70%), which inevitably reduces the LED's luminous efficiency. Furthermore, yellow phosphors age over time, leading to decreased luminous efficiency, color temperature shifts, and a shortened lifespan. Some yellow phosphors also contribute to environmental pollution. Therefore, the method of synthesizing white light using a blue chip combined with yellow phosphors has serious drawbacks.

[0004] Using high-efficiency multi-primary LED chips (e.g., red, yellow, green, cyan, and blue) is another approach to synthesizing white light. This approach effectively mitigates device aging and reduces environmental pollution. According to the U.S. Department of Energy's Semiconductor Lighting Research Program, the efficiency limit for phosphor-converted white light is 250 lm / W, while the efficiency limit for multi-primary LED-synthesized white light is 350 lm / W. Multi-primary LED white light illumination has greater potential than phosphor-converted white light. Therefore, given its superior luminous efficiency, multi-primary LED-synthesized white light is poised to become the next generation of semiconductor lighting technology.

[0005] In LED packaging and application modules, optical control is an indispensable part. It directly affects the light extraction efficiency and light mixing efficiency of LEDs and is a key link in achieving the application requirements of multi-primary color LED lighting. Traditional packaging structures such as imitation lumen packaging and surface mount packaging cannot meet the requirements of uniform light mixing and high extraction efficiency of multi-primary color LEDs. Figure 1 As shown in the figure, multi-primary color LEDs are used to directly synthesize white light. Different color LED chips are distributed in different positions in space. Due to the mismatch of light patterns emitted by different color LED chips, the light emitted by the LED package module is inconsistent in color at different viewing angles in space, resulting in color deviation. Figure 2 As shown. Moreover, when multi-primary color LED package modules are applied to lamps, the secondary lens of the lamp will aggravate the color deviation at different viewing angles. The main reason is that the secondary lens uses refraction to control the propagation direction of light, which will cause dispersion of light emitted by LEDs of different colors. The greater the difference in refractive index between the media, the more severe the dispersion. The larger the incident angle, the more severe the dispersion. The principle diagram is shown in the attached figure. Figure 3 As shown. Taking street lights as an example, in order to achieve road lighting, it is necessary to achieve a wide viewing angle of light along the length of the road, that is, it is necessary to deflect the light towards a large viewing angle, which will make the dispersion particularly serious. As a result, the target plane does not receive the white light synthesized by the multi-primary color chip, but instead has a reddish and yellow-green tint in the area, which greatly reduces the lighting quality and may even cause traffic accidents. In addition, the greater the difference in the refractive index of the interface, the more severe the Fresnel reflection of the light passing through the interface, and thus the lower the light extraction efficiency. The principle diagram is shown in the attached figure. Figure 4 As shown in the figure, assuming a refractive index of 1.5 for the encapsulant and 1 for air, the Fresnel reflection loss when light passes from the encapsulant to air or vice versa is approximately 4%. Therefore, in a conventional package structure, light from the chip passes through the primary lens, the air gap layer, and then the secondary lens. This results in three Fresnel loss interfaces, significantly reducing light extraction efficiency. Therefore, current packaging methods are not suitable for multi-primary LED light sources. Summary of the Invention

[0006] The purpose of the present invention is to provide a module structure of a multi-primary color LED light source, which solves the problem of uneven light output of the multi-primary color LED light source and improves the light extraction efficiency of the multi-primary color LED light source by introducing a new packaging colloid layer and combining the chip and lamp bead distribution method.

[0007] The object of the present invention is achieved like this:

[0008] A module structure of a multi-primary color LED light source includes several LED lamp beads, a second thermal interface layer, a secondary optical lens, a second substrate layer and a sealing ring. The characteristics are: each LED lamp bead includes several LED chips with different main wavelengths, leads, a primary optical lens, a first thermal interface layer and a first substrate layer, the LED chips with different main wavelengths are arranged in a staggered manner, the primary optical lens seals the several LED chips on the first substrate layer; the several LED lamp beads are respectively fixed to the second substrate layer through the material layer of the second thermal interface layer, the secondary optical lens is installed on the second substrate layer and covers the LED lamp beads, and is sealed by the sealing ring, the patch angles of the several LED lamp beads on the second substrate layer are not completely the same; a third encapsulation colloid layer is included between the primary optical lens and the secondary optical lens to ensure that there is no air gap between the LED chip and the light-emitting surface.

[0009] Furthermore, each LED lamp bead contains 2 to 99 high-efficiency vertically structured LED chips. The main wavelength range of the LED chips is 380nm to 780nm, and includes at least two or more main wavelengths. Each LED lamp bead directly synthesizes white light through LED chips with different main wavelengths.

[0010] Furthermore, the plurality of LED chips are distributed on the first substrate layer in a circular arrangement or a polygonal arrangement.

[0011] Furthermore, the second packaging substrate layer contains 3 to 99 LED lamp beads.

[0012] Furthermore, the secondary optical lens is a spherical cap lens or a free-form surface lens.

[0013] Furthermore, the secondary optical lens is an integrated structure or an independent structure. For the integrated structure, adjacent secondary optical lenses are interconnected; for the independent structure, adjacent secondary optical lenses are completely independent.

[0014] Furthermore, the material of the primary optical lens is silicone or epoxy resin, the material of the secondary optical lens is one of polycarbonate, polymethyl methacrylate, glass, silicone or epoxy resin, and the material of the third encapsulation colloid layer is silicone. The refractive indices of the three layers of materials are matched, and the elastic modulus of the material of the third encapsulation colloid layer is smaller than the elastic modulus of the primary optical lens material and the elastic modulus of the secondary optical lens material.

[0015] Furthermore, the first substrate layer is one of a ceramic substrate, an aluminum substrate, a copper substrate or a silicon substrate, and the corresponding LED lamp beads adopt a packaging structure of one of a ceramic package, a chip-on-board package or a silicon-based package.

[0016] Furthermore, the second substrate layer is an aluminum substrate or a copper substrate.

[0017] Compared with the prior art, the above technical solution proposed by the present invention has the following advantages:

[0018] 1. By filling the third layer of encapsulation colloid between the primary optical lens and the secondary optical lens, it can ensure that there is no air gap between the LED chip and the light-emitting surface of the secondary optical lens, weakening the dispersion caused by the different deflection angles of different colors of light caused by the existence of air gap, as shown in the attached figure. Figure 5 As shown;

[0019] 2. The staggered arrangement of LED chips in LED lamp beads realizes internal light mixing of LED lamp beads. At the same time, several LED lamp beads are mounted on the second substrate layer at different angles to achieve light mixing between LED lamp beads. Finally, the multi-primary color LED light source module structure achieves effective light mixing effect. At the same time, the introduction of the third layer of encapsulation colloid layer effectively reduces the Fresnel reflection loss between the interfaces, thereby improving the light output efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the distribution of multi-primary color LED light source chips;

[0021] Figure 2 Schematic diagram of the distribution of light emitted by LED chips of different colors and the color of the target plane;

[0022] Figure 3 This is a schematic diagram of the traditional packaging structure and the light transmission corresponding to chips of different colors;

[0023] Figure 4 Schematic diagram of light transmission and reflection when light passes through interfaces with different refractive indices;

[0024] Figure 5 Schematic diagram of the packaging structure of the present invention and the light transmission corresponding to chips of different colors;

[0025] Figure 6 Schematic cross-sectional view of a light mixing and light extraction module of a two-primary-color LED light source according to embodiment 1 of the present invention;

[0026] Figure 7 Schematic top view of the light mixing and light extraction module of the two-primary color LED light source in Example 1 of the present invention;

[0027] Figure 8 This is a cross-sectional schematic diagram of a two-primary-color LED lamp bead according to Example 1 of the present invention;

[0028] Figure 9 This is a top view schematic diagram of a two-primary-color LED lamp bead according to Example 1 of the present invention;

[0029] Figure 10This is a partially enlarged schematic cross-sectional view of a light mixing and light extraction module of a two-primary-color LED light source according to embodiment 1 of the present invention;

[0030] Figure 11 This is a partially enlarged top view of a light mixing and light extraction module of a two-primary-color LED light source according to Example 1 of the present invention;

[0031] Figure 12 Schematic cross-sectional view of a light mixing and light extraction module of a two-primary-color LED light source according to embodiment 2 of the present invention;

[0032] Figure 13 Schematic diagram of a top view of a four-primary-color LED lamp bead according to embodiment 3 of the present invention

[0033] Figure 14 Schematic cross-sectional view of a light mixing and light extraction module of a five-primary-color LED light source according to embodiment 4 of the present invention;

[0034] Figure 15 Schematic top view of the light mixing and light extraction module of the five-primary-color LED light source according to embodiment 4 of the present invention;

[0035] Figure 16 This is a schematic cross-sectional view of the five-primary-color LED lamp bead structure according to Example 4 of the present invention;

[0036] Figure 17 This is a top view schematic diagram of a five-primary-color LED lamp bead according to Example 4 of the present invention;

[0037] Figure 18 This is a partially enlarged schematic cross-sectional view of a light mixing and light extraction module of a five-primary-color LED light source according to embodiment 4 of the present invention;

[0038] Figure 19 This is a partially enlarged top view of a light mixing and light extraction module of a five-primary-color LED light source according to Example 4 of the present invention;

[0039] Figure 20 Schematic cross-sectional view of a light mixing and light extraction module of a five-primary-color LED light source according to embodiment 5 of the present invention;

[0040] Figure 21 This is a partially enlarged top view of a light mixing and light extraction module of a two-primary-color LED light source according to embodiment 6 of the present invention. DETAILED DESCRIPTION

[0041] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0042] Example 1:

[0043] like Figure 6As shown in the figure, a module structure of a multi-primary color LED light source includes an LED lamp bead 11, a thermal interface material layer (i.e., a second thermal interface layer) 12, a free-form surface lens 13, an aluminum substrate 14, and a sealing ring 15. The LED lamp bead 11 is fixed to the aluminum substrate 14 through the thermal interface layer material layer 12, and the free-form surface lens 13 is installed on the aluminum substrate 14 and covers the LED lamp bead 11, and is sealed by the sealing ring 15. The material of the free-form surface lens 13 is polycarbonate, and its structure is one-piece, that is, the free-form surface lenses 13 are interconnected. Figure 7 As shown, a total of 22 LED lamp beads 11 are dispersedly arranged on the module structure, and the LED lamp beads 11 are distributed on the aluminum substrate 14 in a rectangular arrangement.

[0044] Among them, LED lamp beads such as Figure 8 As shown, a ceramic package structure is used, including four LED chips 111, gold wire 112, silicone ball cap lens 113, a bonding layer (i.e., first thermal interface layer) 114, and a ceramic substrate 115. The four LED chips 111 are mechanically fixed to the ceramic substrate 115 through the bonding layer 114, and the four LED chips 111 are interconnected with the ceramic substrate 115 through the gold wire 112. The silicone ball cap lens 113 seals the four LED chips 111 on the ceramic substrate 115. Figure 9 As shown, the four LED chips in each LED lamp bead include two red LED chips 1111 with a dominant wavelength of 650nm and two yellow LED chips 1112 with a dominant wavelength of 555nm. The chips with different dominant wavelengths are arranged in a square staggered manner.

[0045] like Figure 10 As shown, a silicone layer 16 is included between the silicone ball cap lens 113 and the free-form surface lens 13 to ensure that there is no air gap between the LED chip 111 and the light-emitting surface of the free-form surface lens 13 .

[0046] like Figure 11 As shown, the patch angles of several LED lamp beads on the second substrate layer are not exactly the same. For the convenience of explanation, a rectangular coordinate system is established, with the upper left corner of LED lamp bead 17 itself as the origin, and the LED chip information is read in a clockwise direction. The LED chip used by LED lamp bead 17 is red, yellow, red, and yellow, and the LED chip used by LED lamp bead 18 is yellow, red, yellow, and red, that is, the patch angle of LED lamp bead 18 on the second substrate layer is 90 degrees different from that of LED lamp bead 17, and so on, to ensure that the patch angles of several LED lamp beads on the second substrate layer are not exactly the same.

[0047] Example 2:

[0048] like Figure 12The figure shows a light mixing and light extraction module for two-primary color LED light sources. The structure of Example 2 is basically the same as that of Example 1. The difference from Example 1 is that the free-form surface lens 21 used in Example 2 is independent, that is, each LED lamp bead 22 corresponds to a free-form surface lens 21, and sealing is achieved by a sealing ring 23.

[0049] Example 3:

[0050] like Figure 13 The figure shows a top-down schematic diagram of the four-primary-color LED lamp beads in the light mixing and light extraction module of the four-primary-color LED light source. The structure of Example 3 is basically the same as that of Example 1. The difference from Example 1 is that the lamp beads used in Example 3 include four chips with different dominant wavelengths, namely: a red light LED chip 3111 with a dominant wavelength of 630nm, a yellow light LED chip 3112 with a dominant wavelength of 560nm, a green light LED chip 3113 with a dominant wavelength of 530nm, and a blue light LED chip 3114 with a dominant wavelength of 460nm. The LED chips with different dominant wavelengths are arranged in a square staggered manner.

[0051] Example 4:

[0052] like Figure 14 As shown, a module structure for realizing a five-primary-color LED light source includes an LED lamp bead 41, a thermal interface material layer (i.e., a second thermal interface layer) 42, a free-form surface lens 43, a copper substrate 44, and a sealing ring 45. The LED lamp bead 41 is fixed on the copper substrate 44 through the thermal interface material layer 42, and the free-form surface lens 43 is installed on the copper substrate 44 and covers the LED lamp bead 41, and is sealed by the sealing ring 45. The material of the free-form surface lens 43 is polymethyl methacrylate, and its structure is independent, that is, each LED lamp bead 41 corresponds to a free-form surface lens 43. Figure 15 As shown, a total of 36 LED lamp beads 41 are dispersedly arranged on the module structure, and the LED lamp beads are distributed on the copper base plate 42 in a circular arrangement.

[0053] Among them, LED lamp beads such as Figure 16 As shown, a chip-on-board package structure is used for packaging, including five LED chips 411, gold wire 412, epoxy resin ball cap lens 413, a bonding layer (i.e., the first thermal interface layer) 414, and a copper substrate 415. The five LED chips 411 are mechanically fixed to the copper substrate 415 through the bonding layer 414, and the five LED chips 411 are interconnected with the copper substrate 415 through the gold wire 412. The epoxy resin ball cap lens 413 seals the five LED chips 411 on the copper substrate 415. Figure 17As shown, the five LED chips in the lamp bead include a red LED chip 4111 with a dominant wavelength of 625nm, a yellow LED chip 4112 with a dominant wavelength of 555nm, a green LED chip 4113 with a dominant wavelength of 520nm, a cyan LED chip 4114 with a dominant wavelength of 500nm, and a blue LED chip 4115 with a dominant wavelength of 455nm. The chips with different dominant wavelengths are arranged in a square staggered pattern. Figure 18 As shown, a silicone layer 46 is included between the ball cap lens 413 and the free-form surface lens 43 to ensure that there is no air gap between the LED chip 411 and the light-emitting surface of the free-form surface lens 43 .

[0054] like Figure 19 As shown, the patch angles of several LED lamp beads on the second substrate layer are not exactly the same. For the convenience of explanation, a rectangular coordinate system is established, with the upper left corner of the LED lamp bead 47 itself as the origin, and the chip information is read in a clockwise direction, and the last one is the center position chip. LED lamp bead 47 uses red, yellow, green, cyan and blue, LED lamp bead 48 uses cyan, red, yellow, green and blue, LED lamp bead 49 uses green, cyan, red, yellow and blue, LED lamp bead 50 uses cyan, red, yellow, green and blue, LED lamp bead 51 uses green, cyan, red, yellow and blue, LED lamp bead 52 uses yellow, green, cyan, red and blue, that is, the patch angles of adjacent LED lamp beads on the second substrate layer differ by 90 degrees, and so on, to ensure that the patch angles of several LED lamp beads on the second substrate layer are not exactly the same.

[0055] Example 5:

[0056] like Figure 20 The figure shows a light mixing and light extraction module of a five-primary-color LED light source. The structure of Example 5 is basically the same as that of Example 4. The difference from Example 4 is that the free-form surface lens 53 used in Example 5 is integrated, that is, the free-form surface lenses 53 are interconnected.

[0057] Example 6:

[0058] like Figure 21 The figure shows a partially enlarged top view of a light mixing and light extraction module of a two-primary color LED light source. The structure of Example 6 is basically the same as that of Example 4. The difference from Example 4 is that the LED lamp bead 61 used in Example 6 is a two-color lamp bead, that is, the lamp bead includes two red light LED chips 6111 with a main wavelength of 620nm and two yellow light LED chips 6112 with a main wavelength of 555, and the chips with different main wavelengths are arranged alternately.

Claims

1. A module structure of a multi-primary color LED light source, comprising a plurality of LED lamp beads, a second thermal interface layer, a secondary optical lens, a second substrate layer, and a sealing ring, characterized in that: Each LED lamp bead includes several LED chips with different main wavelengths, leads, a primary optical lens, a first thermal interface layer and a first substrate layer. The LED chips with different main wavelengths are arranged in an alternating manner. The primary optical lens seals the several LED chips on the first substrate layer; several LED lamp beads are fixed on the second substrate layer through the material layer of the second thermal interface layer respectively, and the secondary optical lens is installed on the second substrate layer and covers the LED lamp beads, and is sealed by a sealing ring. The patch angles of the several LED lamp beads on the second substrate layer are not exactly the same; a third layer of encapsulation colloid layer is included between the primary optical lens and the secondary optical lens to ensure that there is no air gap between the LED chip and the light-emitting surface; the refractive indexes of the primary optical lens, the secondary optical lens and the third layer of encapsulation colloid layer are matched, and the elastic modulus of the material of the third layer of encapsulation colloid layer is smaller than the elastic modulus of the primary optical lens material and the elastic modulus of the secondary optical lens material; the secondary optical lens is a spherical cap lens or a free-form surface lens.

2. The module structure of the multi-primary color LED light source according to claim 1, characterized in that: Each LED lamp bead contains 2 to 99 high-efficiency vertically structured LED chips. The main wavelength range of the LED chips is 380nm to 780nm, and includes at least two or more main wavelengths. Each LED lamp bead directly synthesizes white light through LED chips with different main wavelengths.

3. The module structure of the multi-primary color LED light source according to claim 1, characterized in that: The plurality of LED chips are distributed on the first substrate layer in a circular arrangement or a polygonal arrangement.

4. The module structure of the multi-primary color LED light source according to claim 1, characterized in that: The second substrate layer contains 3 to 99 lamp beads.

5. The module structure of the multi-primary color LED light source according to claim 1, characterized in that: The secondary optical lens is an integrated structure or an independent structure. For the integrated structure, adjacent secondary optical lenses are interconnected; for the independent structure, adjacent secondary optical lenses are completely independent.

6. The module structure of the multi-primary color LED light source according to claim 1, characterized in that: The material of the primary optical lens is silicone or epoxy resin, the material of the secondary optical lens is one of polycarbonate, polymethyl methacrylate, glass, silicone or epoxy resin, and the material of the third encapsulation colloid layer is silicone.

7. The module structure of the multi-primary color LED light source according to claim 1, characterized in that: The first substrate layer is one of a ceramic substrate, an aluminum substrate, a copper substrate or a silicon substrate, and the corresponding LED lamp beads adopt a packaging structure of one of a ceramic package, a chip-on-board package or a silicon-based package.

8. The module structure of the multi-primary color LED light source according to claim 1, characterized in that: The second substrate layer is an aluminum substrate or a copper substrate.

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