用英语说明手机屏幕主要使用了何种材料，这种材料的组成，并解释和讨论为什么会使用这种材料，基于其特定的属性

Smartphone screens primarily utilize technologies based on three main types of display materials: Liquid Crystal Displays (LCDs), Organic Light-Emitting Diodes (OLEDs), and more recently, AMOLEDs. Each type is composed of different materials and has distinct properties. ### Liquid Crystal Displays (LCDs) **Materials Composition**: - **Glass Substrate**: Provides a stable surface for the display. - **Polarizers**: These are optical filters that transmit light in specific polarization states. - **Color Filters and Liquid Crystal Layer**: Containing red, green, and blue subpixels to create colored images. - **Backlight Unit**: Typically includes LEDs which provide a consistent light source for the panel. *Why Are They Used?* - **Cost-Effectiveness**: LCDs are less expensive to produce. - **Wide Viewing Angles**: Offer good visibility even from off-center angles. - **Brightness and Contrast**: Good brightness levels, although not as vibrant as OLED’s colors. ### Organic Light-Emitting Diodes (OLEDs) **Materials Composition**: - **Substrate**: Often plastic or flexible glass for lightweight and flexible properties. - **Electroluminescent Organic Materials**: Layers of organic molecules sandwiched between cathode and anode layers, emitting light when an electric current is applied. - **Emissive Layers**: Individual subpixels emit their own light for each color (R, G, B). *Why Are They Used?* - **High Contrast Ratios and Black Levels**: OLED pixels can be completely turned off, producing pure blacks. - **Energy Efficiency**: Use less power since they illuminate the areas needed rather than backlighting entire screen like LCDs. - **Flexible Display Capabilities**: Ideal for devices with curved displays due to the flexibility of organic materials. ### Active Matrix OLED Displays (AMOLED) **Materials Composition**: - **Active Matrix Backplane**: Usually made using a thin-film transistor (TFT) technology, controls each individual pixel, enhancing display performance. - **Same Organic Material as OLEDs**: Additional control layer that allows individual pixel addressing and better color management. *Why Are They Used?* - **Vibrant and Accurate Colors**: Due to the nature of organic materials, AMOLEDs can display a very wide color gamut and deep blacks. - **Response Time**: Fast refresh rates make them perfect for dynamic content, reducing motion blur. - **Battery Life Improvement**: Especially beneficial in battery-powered devices, as they save energy by not illuminating black pixels. ### Discussion The choice of display technology in smartphones largely depends on the balance between cost, performance, its application's requirements, and market positioning. Innovations in materials science have thrown new possibilities into the mix. For instance, the use of inorganic materials such as quantum dots in newer displays is offering brighter colors, while phosphorescent OLED materials extend device lifetimes. Each material property dictates not just the visual output but also the overall user experience regarding power consumption, form factor possibilities, and durability. It's a continuous process of optimizing these conflicting priorities, with manufacturers frequently pushing to create displays that offer the best viewing and performance characteristics for their target markets.