LED package manufacturing process and related precautions


one. We can divide the specific manufacturing process of the LED package into the following steps:

1. Cleaning step: Ultrasonic cleaning of the PCB or LED holder and drying.

2. Mounting step: After the silver electrode at the bottom of the LED die is filled with silver glue, the expansion is performed, and the expanded die is placed on the thorn crystal table, and the dies are mounted on the PCB or the LED one by one under the microscope with a stylus. On the corresponding pads, sintering is then performed to cure the silver paste.

3. Pressure welding step: The electrode is connected to the LED die by an aluminum wire or gold wire welding machine for the current injection lead. The LED is directly mounted on the PCB, and an aluminum wire welder is generally used.

4. Packaging step: protect the LED die and bonding wire with epoxy by dispensing. Dispensing on the PCB, there are strict requirements on the shape of the gel after curing, which is directly related to the brightness of the backlight product. This process will also take on the task of phosphors.

5. Soldering step: If the backlight is an SMD-LED or other packaged LED, the LED needs to be soldered to the PCB before the assembly process.

6. Film cutting step: various diffusion films, reflective films, etc. required for backlighting are punched by a punch.

7. Assembly steps: According to the drawings, the various materials of the backlight are manually installed in the correct position.

8. Test procedure: Check whether the photoelectric parameters of the backlight and the uniformity of light output are good.

9. Packing step: Pack the finished product as required and put it into storage.

two. The following is a specific flow chart of the LED lamp bead package:

Every detail in the production process of LED lamp bead package must be strictly controlled. The following detailed explanation of the above flow chart is detailed:

1, the first is the LED chip inspection

(1) Microscopic examination: Whether there is mechanical damage and pitting on the surface of the material, whether the size and size of the LED chip electrode meet the process requirements; whether the electrode pattern is complete

2, the expansion machine expands its film

Since the LED chips are still closely spaced after the dicing, the operation is not conducive to the operation of the post process. We use a film expander to expand the film of the bonded chip. The distance between the LED chips is stretched to about 0.6 mm. It can also be manually expanded, but it is easy to cause problems such as chip falling waste.

3, dispensing

Place silver glue or insulating glue on the corresponding position of the LED bracket. The difficulty of the process lies in the control of the amount of glue, and there are detailed technical requirements in the height of the glue and the position of the glue. Since silver glue and insulating glue have strict requirements in storage and use, the wake-up, stirring and use time of silver glue are all matters that must be paid attention to in the process.

4, ready glue

In contrast to dispensing, the glue is applied to the back electrode of the LED with a glue machine, and then the LED with silver glue on the back is mounted on the LED holder. The efficiency of the preparation glue is much higher than that of the dispensing, but not all products are suitable for the preparation process.

5, hand-piercing

The expanded LED chip is placed on the jig of the lancet table, the LED bracket is placed under the clamp, and the LED chips are punctured one by one under the microscope with the needle. Hand-made thorns have an advantage over automatic loading, making it easy to replace different chips at any time, for products that require multiple chips.

6, automatic loading

In the automatic loading, the two steps are combined with the glue and the chip. First, the silver glue is placed on the LED bracket, and then the vacuum chip is used to suck the LED chip to the moving position, and then placed in the corresponding bracket position. In the process of automatic loading, the equipment should be familiar with the operation and programming of the equipment, and at the same time adjust the glue and installation accuracy of the equipment. In the selection of the nozzle, the bakelite nozzle should be used as much as possible to prevent damage to the surface of the LED chip. In particular, the blue and green chips must be made of bakelite. Because the steel nozzle will scratch the current diffusion layer on the surface of the chip.

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