2.0-inch bar LCD panel: the core component of compact display
As the display core of various small devices, the 2.0-inch bar LCD panel has become the preferred choice for balancing cost and performance with its narrow 16:3 ratio (60mm×11mm) and mature liquid crystal technology. Unlike a complete display screen, this panel focuses on the core performance of the optical display layer, providing highly customized basic components for device manufacturers. It can be matched with backlight, drive circuit and cover plate according to needs, and is widely used in smart home, industrial instrumentation, portable devices and other scenarios.
Core composition and technical characteristics of the panel
1. Liquid crystal layer and pixel structure
Liquid crystal type and arrangement: TN type liquid crystal (mainstream) or IPS type liquid crystal (high-end) is used. TN type realizes the switching control of light through twisted nematic arrangement, with a response time of ≤25ms, which is suitable for static or low-speed dynamic display; IPS type uses plane switching technology to make the liquid crystal molecules arranged in parallel, with a wider viewing angle (170°), better color consistency, and a cost 20-30% higher than TN type.
Pixel layout: 240×48 pixel dot matrix distribution, each pixel is composed of red, green and blue sub-pixels (pseudo-color panel) or single color sub-pixels (monochrome panel), pixel spacing is 0.25mm, ensuring clear text edges without jagged edges, meeting the display requirements of "time, value" and other information.
2. Polarizer and optical film layer
Polarizer configuration: A layer of linear polarizer is attached to the upper and lower surfaces (polarization axis is orthogonal), and the display switch is realized in conjunction with the optical rotation characteristics of liquid crystal molecules. The surface polarizer adopts anti-glare treatment (haze 15%) to reduce ambient light reflection and maintain good readability under indoor lighting.
Brightness enhancement film and diffusion film: The backlight attachment position is reserved under the panel, which can be matched with prism brightening film (increase brightness by 30%) and diffusion film (to evenly distribute light). After matching with the backlight component, the overall brightness can reach 200-400cd/m², meeting the lighting requirements of different scenes.
Performance parameters and customization dimensions
1. Key electrical parameters
Working voltage: driving voltage 3.3V±0.2V, logic voltage 1.8V±0.1V, compatible with mainstream MCU I/O levels, no additional level conversion circuit is required, simplifying the driving design.
Power consumption characteristics: The liquid crystal layer itself has extremely low power consumption (≤0.01W), and the main power consumption comes from the backlight component, which is suitable for battery-powered devices that are sensitive to power consumption (such as electronic counters).
Working temperature: Industrial-grade panels support -20℃ to 70℃, and civilian-grade panels support -10℃ to 60℃. Liquid crystal molecules can still maintain stable arrangement at extreme temperatures to avoid "flower screen" or "black screen".
2. Customization options
Size fine-tuning: The length can be adjusted within the range of 50-70mm (the width changes proportionally) to meet the installation space requirements of different devices. For example, the panel of a shared power bank can be shortened to 55mm to adapt to the body design.
Pixel density and resolution: In addition to the standard 240×48, 128×32 (low resolution, lower cost) or 320×64 (high resolution, display more content) can be customized, with a pixel density range of 80-120PPI.
Interface type: supports 8-bit parallel interface (fast transmission speed) or SPI/I2C serial interface (simple wiring, saving PCB space), interface pin spacing is 0.5mm, suitable for high-density welding.
Production process and quality control
1. Precision manufacturing process
Array and boxing process: TFT (thin film transistor) array is made on the glass substrate through photolithography technology, with an accuracy of ±1μm, to ensure the normal operation of the driving circuit of each pixel; the boxing process adopts precise alignment (error ≤3μm), the upper and lower glass substrates are bonded, and liquid crystal is injected in the middle to ensure uniform thickness of the liquid crystal layer (5-7μm).
Cutting and edge grinding: Laser cutting technology (accuracy ±0.1mm) is used to cut large-size glass substrates into strip panels, and the edges are ground (roughness Ra≤0.5μm) to avoid assembly scratches caused by sharp edges.
2. Quality inspection standards
Optical inspection: 100% brightness uniformity test (required ≥85%), contrast test (≥300:1) and bad pixel detection (allowed ≤1 bright spot or dark spot) are carried out to ensure stable display effect.
Reliability test: Sampling high and low temperature cycle test (-20℃ to 70℃, 100 cycles), vibration test (10-2000Hz, 10g acceleration) and humidity test (95% RH, 40℃, 500 hours) are carried out to verify the stability of the panel in extreme environments.
Compatibility with peripheral components
1. Backlight component matching
Backlight type: It can be matched with side-entry LED backlight (6 0603 LED lamp beads, color temperature 6500K±500K), and the light is evenly distributed to the entire panel through the light guide plate. The backlight thickness can be controlled within 0.8mm, meeting the thin and light requirements of the device.
Brightness adjustment: The backlight supports PWM dimming (frequency 100-1000Hz), dimming range 10-100%, and can automatically adjust the brightness according to the ambient light (need to cooperate with the light sensor), reducing power consumption while improving visual comfort.
2. Driver circuit integration
Driver IC selection: It is recommended to match SSD1306 (monochrome) or ST7735 (pseudo-color) driver chips, support hardware accelerated drawing (such as drawing lines and circles), and simplify software development; IC and panel are bound through COG (Chip On Glass) process to reduce connection points and improve reliability.
Anti-interference design: The connection wiring between the panel and the drive circuit should avoid high-frequency signal paths, and a ground shielding layer should be added if necessary to avoid display anomalies caused by electromagnetic interference (such as screen flickering and garbled characters).
Application scenarios and selection suggestions
1. Selection by scenario
Cost-sensitive equipment: Select a TN-type monochrome panel (240×48 resolution), with side-entry LED backlight and SPI interface, suitable for small household appliances within 100 yuan (such as kitchen timers, electronic scales).
Scenarios with high viewing angle requirements: Select an IPS-type pseudo-color panel, which supports a 170° wide viewing angle and is suitable for devices viewed by multiple people (such as the status screen of a shared device and industrial instruments used by a team).
Equipment for extreme environments: Select an industrial-grade panel (-20℃ to 70℃ operating temperature), with a metal reinforcement frame, for outdoor instruments, small vehicle-mounted display screens and other scenarios.
2. Design considerations
Mechanical matching: The panel thickness is 0.7mm (glass substrate). The total thickness after adding the backlight and cover is recommended to be controlled within 2mm. A 0.1mm assembly gap is reserved to avoid damage caused by extrusion.
Optical matching: The backlight color temperature matches the panel filter (such as 6500K white light with standard RGB filter) to ensure accurate color reproduction (pseudo-color panel); the cover transmittance must be ≥90% to avoid affecting the display brightness.
