Small pitch packaging technology: SMD, COB, GOB

Since the development of the LED display industry, various production and packaging processes have appeared. From the previous straight process, to the surface mount (SMD) process, to the emergence of COB packaging technology, and finally to the emergence of GOB packaging technology.

In the development process of small-pitch manufacturing process, many small-pitch manufacturers have achieved the best solution for small-pitch display. Everyone is in the Eight Immortals.

SMD surface mount technology

SMD: It is an abbreviation for Surface Mounted Devices, meaning: surface mount devices. LED products packaged in SMD (surface mount technology) are used to package lamp cups, brackets, wafers, leads, epoxy materials and other materials into different specifications. The high-speed placement machine is used to solder the lamp bead to the circuit board by high-temperature reflow soldering to form display units with different pitches.

SMD small spacing is generally exposed to the LED lamp beads, or the use of a mask. Due to the mature technology, low manufacturing cost, good heat dissipation effect and convenient maintenance, it also occupies a large share in the LED application market. However, due to serious defects, it is unable to meet the needs of the current market.

1. Low protection level: no moisture, waterproof, dustproof, shockproof and anti-collision. In humid climates, large batches of dead lights and bad lights are prone to occur. In the process of transportation, it is easy to appear the phenomenon of lights and bad lights. It is also susceptible to static electricity, causing dead lights.

2, great damage to the eyes: long time watching will appear glare, fatigue, can not protect the eyes. In addition, there is a “blue hazard” effect. Because the blue LED has a short wavelength and a high frequency, the human eye directly and long-termly accepts the influence of blue light, which is likely to cause retinopathy.

3, LED lamp life is short: lamp performance is affected by environmental factors, service life is greatly shortened, PCB performance is affected by environmental factors, copper ions migrate, resulting in micro-short circuit

4, mask: SMD small spacing using the mask, used in high temperature environment, easy to appear mask bulging, affecting viewing. After using for a period of time, the mask can not be cleaned, causing whitening or yellowing on the scene, which not only looks ugly, but also affects viewing.

COB packaging technology

The COB package is called Chips on Board, which is a technology to solve the problem of LED heat dissipation. Compared with in-line and SMD, it features space saving, simplified packaging, and efficient thermal management.

The bare chip is adhered to the interconnect substrate with a conductive or non-conductive paste, and then wire bonding is performed to achieve electrical connection. If the bare chip is directly exposed to the air, it is susceptible to contamination or human damage, affecting or destroying the function of the chip, so the chip and the bonding wire are encapsulated by glue. This package is also referred to as a soft encapsulation. It has certain advantages in production efficiency, low thermal resistance, light quality, application, cost and so on.

However, as a new technology, COB is insufficiently accumulated in the small-pitch LED industry, the details of the process need to be improved, and the main products of the market are temporarily at a cost disadvantage.

1, poor consistency: because there is no first step to select the light link, resulting in the inability to split the color separation, poor consistency and other issues

2, the modularity is serious: because it is made up of many small unit boards, resulting in inconsistent color and serious modularity.

3, the surface flatness: because it is a single lamp dispensing, resulting in poor flatness, feels grainy

4, maintenance difficulties: due to the need for professional equipment, resulting in difficult maintenance, high maintenance costs, under normal circumstances, return to the factory for maintenance.

5, manufacturing costs: due to high defect rate, resulting in manufacturing costs far exceed SMD small spacing

GOB is the abbreviation of Glue on board. It is a kind of packaging technology. It is a technology to solve the problem of LED lamp protection. It uses an advanced new transparent material to package the substrate and its LED package unit to form effective protection. . This material not only has ultra-high transparency, but also has superior thermal conductivity. The GOB can be adapted to any harsh environment with a small gap to achieve true moisture, water, dust, impact and UV resistance.

Compared with the traditional SMD, it is characterized by high protection, moisture proof, waterproof, anti-collision and anti-UV. It can be applied to more harsh environments and avoid large-scale dead lights and lights.

Compared with COB, it is characterized by simpler maintenance, lower maintenance cost, larger viewing angle, and 180 degree horizontal viewing angle and vertical viewing angle. It can solve the problem that COB can't be mixed, modularity is serious, color separation is poor, surface smoothness is poor, etc. problem.

The production steps of the GOB series new products are roughly divided into 3 steps:

1. Choose the best quality materials, lamp beads, industry ultra-high brush IC solutions, high quality LED chips

2. After the product is assembled, aging for 72 hours before GOB filling, the lamp is tested

3. After the GOB is filled, it will be aged for another 24 hours to confirm the product quality again.

In the small-pitch LED package form of the competition, SMD package, COB packaging technology, Haoxiang photoelectric GOB packaging technology, as to the three who can win in the competition, depends on the advanced technology and market acceptance. Who is the final winner, let us wait and see.