LCD screen

Taking an LCD screen with a capacitive touch screen as an example, the overall structure of the display module can be roughly divided into 3 parts. From top to bottom, they are the protective cover glass, the touch screen, and the display screen. The way to glue these 3 parts together is bonding. There are two methods: Optical bonding and Air Bonding.    Optical Bonding Definition:  Optical Bonding refers to the technology that uses transparent optical glue, liquid OCA glue, OCA glue or SCA glue) to completely bond the touch screen and display screen together seamlessly to form a whole screen. The bonding strength is greatly increased.   Advantages:  Good display effect: the air layer between the screens is reduced, light reflection and loss are reduced, the brightness and contrast are improved, and the display image is clearer and brighter. All-in-one black effect: The boundary between the display area and the non-display area is not obvious, which is conducive to the overall black effect when the entire module is not lit.  Higher brightness: OCA glue fills the gaps, reduces light reflection loss, maintains the cleanliness of both screen, and makes the display effect better.  Low interference: The touch screen and display panel are closely integrated to reduce noise interference on touch signals and improve touch fluency. Improved durability: Optical bonding is beneficial to the stable performance of the SENSOR, and also improves the shock resistance of the entire module, effectively extending the product life of the entire module in harsh environments.  Thinner thickess: The overall thickness is reduced through optical glue bonding, making the device thinner and lighter with narrower borders.    Disadvantages:  Complex process: The production process is complex and requires high technology.  High cost: material costs and manufacturing costs are high, and repair costs after damage are also high.     Air Bonding Definition:  it is also known as Double-tape adhesive bonding, that is, simply sticking the touch screen and the four sides of the display screen with double-sided tape. The middle of the two screens is empty and has air.   Advantages:  Low process cost: The process is relatively simple, just use double-sided tape on the four sides of the screen for bonding, and the production cost is low.  Low maintenance costs: The touch screen and display screen are separate, and damage to one piece will not affect the use of the other, reducing maintenance costs.   Disadvantages:  Poor display effect: there is a gap between the two screens, which is easy to reflect light and dust may enter, and the light from the display screen will be filtered, affecting the visual effect.  Easy to get dust in: Because there is a gap in the middle, dust and dirt can easily enter, affecting the screen cleanliness and display effect.    For different type touch screen,  generally it is air bonding for RTP touch( Resitive touch panel) and LCD screen. Either optical bonding or air bonding for CTP touch(Capative touch panel) and LCD screen.   In summary, choosing Optical bonding or Air bonding mainly depends on the positioning and needs of the product. For devices that pursue the ultimate visual experience and high reliability, full fit is a better choice. For applications that are cost-sensitive or do not require excessive display effects (such as some entry-level equipment or specific industrial equipment), frame stickers are a more cost-effective solution.   Optical Bonding Air Bonding   Air Bonding vs Optical Bonding      

The interface types used for LCD displays are diverse and versatile, including RGB, MCU, LVDS, and MIPI. Below is a brief overview of the structural principles of these interfaces:   RGB Interface: Its transmits signals for the red, green, and blue color components, which are the fundamental elements for constructing color images. Requires signals such as HSYNC (Horizontal Synchronization Signal), VSYNC (Vertical Synchronization Signal), ENABLE, CS (Chip Select Signal), RESET, and sometimes RS (Register Select Signal). It is primarily used in small to medium-sized LCD display devices, such as 2.0", 2.31", 2.4", 2.8", 4.3", 5.0", 7.0", 9.0", and 10.1" screens.   MCU Interface: It is mainly used in the field of microcontrollers. Widely adopted in smaller-sized mobile phones, featured of cost-effectiveness. Standardized as the 8080 bus standard proposed by Intel, also referred to as DBI (Data Bus Interface), MPU (Microprocessor Interface), or CPU Interface. It includes two modes: 8080 and 6800, differing in timing. It supports data transmission of 8, 16, 18, and 24 bits. Its typical signals such as WR (Write Signal), RD (Read Signal), RS, RESET, and CS. Advantages: simple and convenient control, eliminating the need for clock and synchronization signals. However, it consumes GRAM, limiting its use to smaller screens, typically 4" and below, such as 2.0", 2.31", 2.4", and 2.8" screens.   LVDS Interface: LVDS (Low Voltage Differential Signaling) is a new generation of high-speed, long-distance transmission interface. LVDS interface is also recognized as a low-voltage differential signaling technology interface developed to overcome the drawbacks of TTL-level transmission, such as high power consumption and EMI (Electromagnetic Interference) for broadband high-rate data transmission. Utilizes very low voltage swings (approximately 350mV) for differential data transmission over two PCB traces or a pair of balanced cables. Compared to TTL interfaces, LVDS requires fewer cables, offers higher speeds, and consumes less power. LVDS interface is widely used in high-resolution LCD displays and high-speed transmission applications.   MIPI Interface: MIPI (Mobile Industry Processor Interface) is designed specifically for mobile devices. MIPI Standards is a newly standard with ongoing modifications and improvements. Mostly its mature interface applications include DSI (Display Interface) and CSI (Camera Interface). CSI/DSI refer to their respective applications for cameras or displays, both having complex protocol structures. MIPI interface an transmit multiple data and control signals per clock cycle, making it faster and more capable than TTL and LVDS interfaces. It is widely used in modern smartphones, tablets, and other mobile devices.   Each of these interfaces has unique structural principles, suitable for different application scenarios and device types. When selecting an LCD screen interface for customization, the choice is primarily determined by the client's motherboard interface. Through software driver matching, the screen can be activated, realizing the product's display solution.