LED package of more than 100 kinds of structural forms

LED packaging technology, there are three elements: the package structure design, selection of appropriate packaging materials and process level.

 

There are more than 100 kinds of LED package types, including more than 40 kinds of Lamp series, 30 kinds of SMD (Chip LED and TOP LED) series, 30 kinds of COB series, PLCC, high power package, Modular packaging, packaging technology to closely follow and meet the needs of LED application product development.

 

LED packaging technology, the basic content

 

LED packaging technology, the basic requirements are: to improve the light efficiency, high light color performance and device reliability.

 

(1) to improve the light efficiency

 

LED package out of the light efficiency of up to 80 to 90%.

 

â‘  choose a better transparency of the packaging materials: transparency ≥ 95% (1mm thickness), refractive index greater than 1.5 and so on.

 

â‘¡ selection of high excitation efficiency, high-dominance of the phosphor, particle size appropriate.

 

â‘¢ mounted substrate (reflective cup) to have high reflectivity, high luminous rate of the optical design shape.

 

â‘£ choose the appropriate packaging process, especially the coating process.

 

(2) high light color performance

 

LED light color of the main technical parameters: height, glare, color temperature, color, color tolerance, light flashing.

 

CRI ≥ 70 (outdoor), ≥ 80 (outdoor), ≥ 90 (art galleries, etc.).

 

Color tolerance ≤ 3 SDCM ≤ 5 SDCM (during life)

 

Package to be used to achieve the combination of multiple primary colors, focusing on improving the LED spectral distribution of the amount of radiation SPD, near the distribution of the amount of sunlight to the spectrum. To pay attention to the development and application of quantum dot phosphor, to achieve better light color quality.

 

(3) LED device reliability

 

LED reliability includes LED device performance under various conditions and a variety of failure mode mechanism (LED packaging material degradation, the impact of integrated stress, etc.), which is mainly referred to the reliability of the characterization of the value of life, the current LED device life is generally 3 to 5 hours, up to 5 to 10 million hours.

 

â‘  use the appropriate packaging materials: bonding strength should be large, small stress, good match, air tightness, temperature, moisture (low water absorption), anti-UV and so on.

 

â‘¡ package heat dissipation material: high thermal conductivity and high conductivity of the substrate, high thermal conductivity, high conductivity and high strength of the solid crystal material, the stress should be small.

 

â‘¢ the appropriate packaging process: loading, pressure welding, packaging and other combination of strong, the stress should be small, combined to match.

 

LED light integrated packaging technology

 

LED light integrated package structure existing more than 30 types, is gradually moving toward system integration package, is the future development direction of packaging technology.

 

(1) COB integrated package

 

COB integrated package of existing MCOB, COMB, MOFB, MLCOB more than 30 kinds of packaging structure, COB packaging technology matures, the advantage of low cost. COB package now accounts for about 40% of LED light source market, the luminous efficiency of 160 ~ 178 lm / w, thermal resistance of up to 2 ℃ / w, COB package is the recent trend of LED packaging development.

 

(2) LED garden-level package

 

Crystal-level package from the extension made of LED devices as long as a dicing, LED lighting is the demand for multi-system integrated package, the general substrate with silicon material, without solid crystal and pressure welding, and dispensing molding, forming system integration package , Its advantage is good reliability, low cost, is one of the packaging technology development.

 

(3) COF integrated package

 

COF integrated package is a large-area power LED chip assembled on a flexible substrate. It has the advantages of high thermal conductivity, thin layer flexibility, low cost, uniform light output, high luminous efficiency, flexible surface light source, etc., and can provide line light source, surface light source and Three-dimensional light source of a variety of LED products, but also to meet the LED modern lighting, personalized lighting requirements, but also as a generic type of packaging components, the market prospects.

 

(4) LED module integrated package

 

Modular integrated package generally refers to the LED chip, drive power, control part (including IP address), parts and other system integration package, collectively known as the LED module, with a saving material, reduce costs, can be standardized production, easy maintenance and many other advantages , Is the LED packaging technology development.

 

(5) flip chip packaging technology

 

Flip chip packaging technology is a chip, substrate, bump to form a space, so the chip out of the package has a small size, high performance, short wiring, etc., using ceramic substrate, chip-chip, eutectic process, direct pressure To achieve high power lighting performance requirements.

 

With the gold-tin alloy chip will be pressed on the substrate, replacing the previous silver plastic process, "direct pressure" instead of the past "reflow", with excellent electrical conductivity and thermal conductivity area. The packaging technology is an important trend of high-power LED packaging.

 

(6) free chip technology package

 

Free packaging technology is a technology integration, the use of flip-chip, no solid crystal glue, gold wire and stent is a semiconductor packaging technology in 70 kinds of process formation.

 

PFC package-free chip products can enhance the luminous efficiency to 200lm / w, light angle greater than 300 degrees ultra-wide-angle full-beam design, do not use the secondary optical lens, will reduce the loss of light efficiency and reduce costs, but to invest expensive equipment.

 

PFC new products LED lighting market, especially in the application of candle lights, not only can simulate the shape of tungsten filament lamp, and can break the heat volume limit.

 

(7) LED other package structure

 

â‘ EMC package structure: Embedded integrated package (Embedded LED Chip) will not directly see the LED light source.

 

(2) Epoxy Molding Compound (Epoxy Molding Compound) Epoxy Molding Compound encapsulation technology, with high heat resistance, high integration, anti-UV, small size and other advantages, but poor air tightness, is now in mass production.

 

â‘¢COG package: (Chip On Glass) LED chip will be placed on the glass substrate for packaging.

 

â‘£ QFN packaging technology: a small pitch pixel display unit is less than or equal to P.1, the package used in the form, will replace the PLCC structure, the market prospects.

 

⑤ 3D packaging technology: three-dimensional form of packaging technology, is being developed.

 

â‘¥ power frame packaging technology: (Chip-in-Frame Package) in a small package on the framework of power LED chip, the industrialization of light effect has reached 160 ~ 170lm / w, up to 200lm / w or more.

 

LED packaging materials

 

LED packaging materials, many varieties, and is constantly evolving, here is a brief introduction.

 

(1) packaging materials

 

Epoxy resin, epoxy molding compound, silicone, silicone, etc., technically on the refractive index, internal stress, adhesion, air tightness, high temperature, UV and other requirements.

 

(2) solid crystal material

 

â‘  solid crystal plastic: resin and silicone, filled with metal and ceramic materials.

 

â‘¡ eutectic: AuSn, SnAg / SnAgCu.

 

(3) substrate material: copper, aluminum and other metal alloy materials

 

â‘  ceramic materials: Al2O3, AlN, SiC and so on.

 

â‘¡ aluminum ceramic materials: known as the third generation of packaging materials AlSiC, AlSi and so on.

 

â‘¢ SCB substrate material: multi-layer die substrate, good heat dissipation (thermal conductivity 380w / m.k), low cost.

 

â‘£ TES polycrystalline semiconductor ceramic substrate, heat transfer speed.

 

(4) thermal material: copper, aluminum and other metal alloy materials

 

Graphene composite materials, thermal conductivity 200 ~ 1500w / m.k.

 

PCT high-temperature special engineering plastics (poly-1,4-cyclohexanedimethylene terephthalate), plus ceramic fiber, high temperature, low water absorption.

 

Thermal engineering plastics: non-insulated thermal engineering plastics, thermal conductivity 14w / m.k.

 

Insulation type thermal engineering plastics, thermal conductivity 8w / m.k.

 

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