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As numbers of smart products continues to grow, an increasing variety of terminal products for different industries and usage environments have emerged into people's view, and the requirements for LCD displays have also gradually escalated, such as in industrial handheld terminals, walkie-talkie devices, instruments, and so on. Since these devices are often used outdoors, the relevant LCD displays are required to remain clearly visible under sunlight to facilitate accurate operations.   What Makes LCD Readable Under Sunlight? For an LCD to be readable in the very bright outdoor environment, the brightness of the LCD screen needs to exceed the intensity of light reflected from the display surface. To be comfortably visible to the human eye, the brightness of the LCD should be at least 2.5 times that of its reflected light.   How to Achieve LCD Sunlight Readable? It is approached from two aspects: increasing brightness or reducing reflection.   1. Increasing Backlight Brightness to Create High-Brightness Displays Advantages: Directly enhances screen brightness to ensure clear visibility in bright environments. Disadvantages: Increases power consumption, size, and cost, and may shorten backlight lifespan due to the higher current and denser LED arrangement required. Applications: Ideal for outdoor use, especially for devices that are not extremely sensitive to power consumption and cost, such as industrial handheld terminals and outdoor advertising boards.   2. Using Optical Bonding to Reduce Reflection Advantages: Improves contrast by reducing specular reflection, without significantly increasing backlight brightness, thus maintaining lower power consumption and cost. Disadvantages: Requires precise optical design and high-quality optical adhesives, increasing manufacturing complexity and cost. Additionally, it may have limited environmental adaptability, performing less optimally at extreme angles or in extreme weather conditions. Applications: Suitable for outdoor devices that require high contrast but do not want to excessively increase power consumption and cost, such as high-end walkie-talkies and professional instruments. 3. Using Transflective LCD Advantages: Can utilize ambient light as a light source, enhancing outdoor display brightness while reducing backlight usage and saving energy. Disadvantages: Displays less optimally indoors or in low-light environments. Additionally, the partially reflective mirror layer blocks some backlight, compromising indoor display performance. Transflective LCDs are also more expensive than fully transmissive LCDs. Applications: Ideal for devices that need good display performance both outdoors and indoors, with some tolerance for higher costs, such as portable navigation devices and outdoor adventure equipment. 4. Using Anti-Reflection (AR) and Anti-Glare (AG) Films or Circular Polarizers Advantages: AR films reduce reflection on the screen surface, improving visibility; AG films diffuse reflected light, reducing glare; circular polarizers further reduce reflection and enhance color performance. These methods are usually cost-effective and easy to implement. Disadvantages: May require periodic replacement or cleaning to maintain optimal performance, especially in heavily polluted outdoor environments. Applications: Widely applicable to various LCD screens requiring improved readability under sunlight, such as smartphones, tablets, and in-vehicle displays.   There are various methods to improve the readability of LCD screens under sunlight, each with its unique strengths and limitations. The most suitable approach depends on the specific use case and device requirements.

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 display modes of LCD (Liquid Crystal Display) primarily encompass reflective mode, transmissive mode, and transflective modes (also known as transreflective mode), with these modes intimately related to the selection of backlight solutions. Below is a detailed analysis of these three LCD display modes and the choice of backlight schemes: Reflective Mode . Transmissive Mode   Transflective Mode     Reflective Mode : （Reflective LCD） Features: Display content relies on ambient light sources for illumination, hence this type of LCD does not require backlighting. Reflective LCDs feature reflective rear polarizers, allowing only light from the front of the LCD to be projected onto it, making them suitable for environments with available light sources. Applications: Commonly used in brightly lit environments, such as electronic readers and watches under direct sunlight outdoors. Advantages: Eliminates the need for backlighting, resulting in low energy consumption, ideal for use in well-lit environments.   Transmissive Mode: (Transmissive LCD) Features: Transmissive LCDs have transmissive front and rear polarizers, allowing most backlight rays to pass through both polarizers and the LCD cell, reaching the viewer's eyes for display. This type of LCD is suitable for dimly lit environments. Application: Ideal for workspaces without ambient light sources, relying on an external backlight source, such as indoor applications. Advantages: Capable of providing clear display effects in poorly lit environments.   Transflective Mode:  (Transreflective mode, Transreflective LCD) Features:  Transflective LCDs combine features of both reflective mode and transmissive mode, incorporating both backlighting and reflective polarizers. As a result, this type of LCD is suitable for both brightly lit outdoors and dimly lit indoors. Applications: Perfect for environments with varying light conditions, such as outdoor applications and car displays. Advantages: Integrates the strengths of both reflective and transmissive modes, ensuring stable display performance under different lighting conditions.   The choice of LCD display mode and backlighting scheme depends on specific application scenarios and requirements. Reflective mode is suitable for well-lit environments without the need for backlighting; transmissive mode excels in dimly lit environments, necessitating LED backlighting; whereas transflective mode combines the benefits of both, catering to environments with significant light variations. When selecting a backlighting scheme, factors such as cost, brightness, color performance, and power consumption must also be taken into consideration.

  COG (Chip-on-Glass) is an advanced packaging technology for electronic components, particularly suitable for the packaging of LCD (Liquid Crystal Display) driver IC. In this technology, the driver IC is directly bonded onto the glass substrate, then the kind LCD module is called COG LCD module.  The whole COG LCD module is consisted of 3 parts, including LCD panel, COG driver IC and the connector of FPC or PIN, as showed.    Compared with other traditional COB, SMT type module, COG display module features with advantages: Small Size COG technology significantly reduces the size of products. Since the driver ICs are directly bonded on the LCD glass, no need for components such as PCB boards and fixed pins, enabling a more compact product design. This miniaturization not only helps reduce the volume, weight, and thickness of COG display module but also promotes thinner device designs.   Compactness COG type IC enhances the compactness of products. The LCD internal layout is directly connected to the pins of the COG IC, eliminating the need for connecting wires and space required by traditional packaging methods such as COB and SMT structures. This compact design makes the entire display module more concise and efficient.   High Reliability COG packaging technology also enhances the display module’s reliability. The direct connection between the COG driver IC and the LCD layout, along with the full coverage of the bonding area with black glue, makes the display module endurable to environmental factors such as air, humidity, and temperature. Additionally, as COG IC requires bonding process once only, reducing the possibility of failure possibility.   Low Power Consumption In terms of power consumption, COG modules also have good performance. Since the COG driver ICs are directly bonded on the LCD glass substrate, the signal transmission path is minimum shortened, reducing energy loss and achieving lower power consumption.   Fast Response COG packaging technology features fast response characteristics. Due to the shorter distance between the IC and the LCD panel, signal transmission is faster, resulting in faster response speeds and refresh rates.   Design Flexibility COG driver ICs are small in size and can be adjusted according to design needs, allowing them to be placed on any side of the LCD panel. This design flexibility makes COG display module adaptable to various application fields and LCD technology.   Cost-effectiveness Compared with COB, SMT type module, COG LCD module also offers significant cost benefits. Its essential simple structure of LCD+COG IC+FPC, ,the elimination of PCB boards and other components has reduced material and manufacturing costs. At the same time, the highly automated COG bonding production line has improved the yield rate, reduced waste losses, and further enhanced cost-effectiveness.   In summary, the COG display module, with its significant advantages such as thin design, high reliability, design flexibility, and cost-effectiveness, has become the preferred choice for many electronic equipment applications. Whether it's consumer electronics, industrial equipment, or medical devices, the COG display module can provide excellent display effects and stable performance.      

Monochrome Liquid Crystal Display (LCD) is one of LCD display technology that can only display a single color. Different from colorful TFT display,  This type of monochrome LCD display typically presents background/image variations of only one color, such as white, green, red, etc. Its structure is illustrated in the figure below: Based on the different monochrome LCD technologies, they can be classified into three main categories: TN (including HTN), STN (including FSTN, DFSTN), and VATN LCD. TN( Twisted Nematic) technology, whose liquid crystal molecules are typically twisted at a 90° angle inside LCD cell. STN( Super Twisted Nematic) technolgy, features a larger twisting angle typically reaching 240°, compared to TN technology . VATN technology, differs from the conventional TN/STN liquid crystal technologies in terms of twisted orientation and crossed polarizers. VATN LCD employs a vertically aligned liquid crystal molecule structure, where the liquid crystal molecules are perpendicular to the electrodes on the LCD substrate. In power off state, the arrangement of VATN liquid crystal molecules is perpendicular to the glass substrate, unlike conventional TN/STN LCDs. This alignment blocks light from passing through the polarizers, resulting in a deep black color. However, when a voltage is applied on both sides, the liquid crystal molecules begin to tilt and collapse, allowing the previously blocked light to penetrate the polarizers, exhibiting a pure white color. This significant enhancement in contrast ratio makes VATN technology visually superior to TN technology. Features of VATN LCD Technology： Advanced Visual Effect: a pure black background for enhanced product elegance. High Contrast: Ultra-high contrast ratio reaching up to 500 or even 1200:1 Ultra-Wide Viewing Angle: Wider viewing angles compared to TN and STN technologies, and full-view VA up to 180° Wide Operating Temperature: with operating temperatures range -30 to 85℃, feasible for automotive applications.   VATN LCD with Color 1.VA LCD with color backlight The most classic visual effect of VA LCD is white text-on pure black background, with the highest contrast. While the backlight of VA LCD is not limited to white. It can also be paired with backlights of other colors, such as red, green, and blue, to create different visual effects. By changing the color of the backlight, VA LCD module could present a richer and more unique color representation, meeting the needs of different application scenarios.   2.VA LCD with color filter or color printing   VA LCD can be also added with color silkscreen printing or color filter technology to enrich the color palette of the fixed displayed content, for example icon, buttons,. This application not only enhances the attractiveness and visual impact of the display but also satisfies user demands for colorful and vivid content. Application Fields: With its high contrast ratio and wide viewing angles, VA LCD has become the popular LCD technology solution in the monochrome display market. It is widely used in various consumer electronics, white goods, smart homes, industrial equipment, and automotive products.  

Capacitive and resistive touch panel are the two main types of touchscreen technology, each exhibit unique characteristics in multiple aspects. Capacitive touch Panel（CTP） The structure of CTP mainly consists of a glass panel, a conductive layer (such as ITO), an insulating layer (such as tempering glass or plastic), and another conductive layer. Its working principle is based on capacitive sensing, achieving touch functionality through human body current sensing. When a finger contacts the metal layer of the touch screen, a coupled capacitance is formed, and the precise location of the touch point is determined by calculating the current ratio flowing through four electrodes.   Advantages of capacitive touch: √  Support for multi-touch function. √  High light transmittance >85% and vivid colors. √  Fast response time is less than 3ms. √  Surface cover covers such as tempered glass of hardness up to 7H, offering excellent scratch resistance and durability. √  Endurance against various contaminants like water, fire, radiation, static electricity, dust, or grease. √  High life expectancy: each touch point capable of enduring over 50 million touches and maintaining cursor stability after calibration. Disadvantages: • High cost. • Incapability being operated with fingernails or insulating materials for touch input. • Unavailability use with gloves or when the screen is wet. • Easy interference from surrounding conductors and temperature variations.     Resistive touch panel(RTP) RTP, consist of a glass or organic glass base coated with a transparent conductive layer (ITO film), and a hardened and scratch-resistant cover whose inner surface is also coated of ITO layer. There are many tiny transparent insulating points between the two layers of conductive layers to separate them.   Resistive touchscreens operate based on the principle of resistance, determining touch location through pressure sensing. When the screen surface is pressed, the top layer is compressed, causing the two ITO layers to contact each other, resulting in a change of resistance value. The controller calculates the coordinates of the touch point based on the detected resistance change and performs corresponding operations accordingly. This technology requires physical pressure on the screen to register a touch.   Advantages of resistive touch: √ Lower cost √ Good response sensitivity and reduced susceptibility to misoperations. √ Ability to withstand various harsh environments, resisting dust and moisture. √ Compatibility perform with any object for touch input, non-conductive objects like pen.    √ Perform feasibility with gloves, or wet screen. Disadvantages: • Support for single-touch only • Slower response speed • Inferior light transmittance compared to capacitive screens • Outer film susceptibility to scratches, potentially rendering the touchscreen unusable • Limited lifetime Expectancy: hitting touch about 1 million and a strokes touch about 100,000 times for 4-wire RTP as an example.   In summary, CTP touch and RTP touch each have their strengths and weaknesses, suitable for different application scenarios.  For instance, capacitive touch may be more suitable for situations requiring high precision, vivid color reproduction, and fast response times, such as smartphones and tablets. On the other hand, resistive touch may be more appropriate for cost-sensitive environments, harsh conditions, or operations involving water or while wearing gloves, such as in industrial equipment and ATMs.  

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.