E-cigarettes with screens are currently a hot topic in the industry. LED digital tubes are becoming increasingly popular due to their cost-effectiveness. Let's take a closer look at the working principle, structure, and production process of this type of display.

E-cigarettes with screens are currently a hot topic in the industry. Among them, LED digital tubes are the most common and mature, and are developing in the direction of larger size and flexibility. Let's take a closer look at the working principle, structure, and production process of this type of display.

1. Introduction and Working Principle

LED digital tubes (LED segment displays, LED modules) are a very common digital information display device today, widely used in various digital products, home appliances, industrial digital instruments, and other fields.

LED digital tubes are actually composed of seven light-emitting diodes arranged in a figure-8 shape, with a decimal point making the total number eight. These segments are represented by the letters a, b, c, d, e, f, g, and dp. When voltage is applied to specific segments of the digital tube, they illuminate, ultimately displaying the content.

II. Structural Composition

A digital tube is simply composed of pins (pins), a plastic shell (PC, PPO), a PCB, light-emitting diodes (LEDs), a display panel, die-bonding adhesive, high-temperature tape, and encapsulation adhesive. After purchasing the raw materials, they undergo quality inspection, testing their performance and appearance. Only qualified products are shipped to the warehouse and put on the production line, marking the beginning of the digital tube production journey.

III. Production Process

The common manufacturing process for digital tubes includes: PIN insertion, die bonding, wire bonding, pre-testing/semi-finished product testing, glue filling, labeling and film pasting, finished product testing, and packaging.

The first major process involves assembling the PCB and guide pins. An automatic guide pin jumper typically inserts the guide pins into the PCB holes and then rivets them to the PCB through press-fitting.

The second process is bonding, which involves bonding the light-emitting chip and aluminum wire. The light-emitting chip is bonded using automated chip bonding equipment. First, a die-bonding adhesive is applied to the PCB, followed by the placement of the chip. The adhesive is then cured at high temperature to secure the chip. Next, aluminum wire bonding is performed, with one end soldered to the PCB and the other to the light-emitting chip.

The third process is testing, where the bonded product undergoes electrical testing to detect problems such as short circuits, open circuits, leakage, and misalignment. However, many manufacturers omit this testing step after completing the second quality control step.

The fourth process is potting. After degassing the sealant, typically epoxy resin, through potting, the product that passed the third test is placed into a pre-potted plastic casing and then cured at high temperature for a long period of time.

The fifth process is finished product testing. The cured digital tube is then tested for performance. Performance testing is similar to the third process, but the relevant parameters can be adjusted appropriately (depending on customer requirements). Some specialized digital tubes require additional steps, such as applying a mask and shaping the guide pins.

The sixth process is packaging. This process primarily involves product appearance inspection, code printing, and packaging. Each company may add, subtract, or change individual processes, all of which are adjusted based on internal process requirements.

IV. Selection

Font height or size, such as 0.4-inch, 0.56-inch, 0.8-inch, etc.

The number of digits in the digital tube determines the maximum display content of a display component.

The light color (wavelength) of the digital tube, such as single red, yellow, blue, green, white, RGB, etc.

The brightness of the digital tube, such as normal brightness or high brightness.

The operating voltage and current of the digital tube.

The color of the screen printing (panel), generally available in creamy white, black, or gray.

Internal connection method: common cathode or common anode.

Operating life.

Operating temperature and humidity.

Other performance characteristics, such as waterproof rating, dustproof, UV resistance, crack resistance, flame resistance, and strong impact and aging resistance.

The appearance of LED digital tubes should be uniform in color, free of localized discoloration and bubbles.

According to incomplete statistics, the digital tube suppliers related to the e-cigarette industry include: Qishun Da, Guoyexing, Yusheng Xinlong, Yongtian Optoelectronics, Fengyifang Optoelectronics, Chuangyijia, Mingcheng Electronics, Wanshi Optoelectronics, etc.