Knowledge of polarizing film (polarizing plate)

Polarizer or polarizer is an optical element made using the principle of polarization of light. It can control the passage of light in a specific direction while blocking light from other directions, thereby achieving the effect of controlling the direction of light and filtering out stray light. In many application fields, such as liquid crystal displays (LCDs), photography equipment, sunglasses, etc., polarizers play an important role. This article will provide a detailed introduction to the characteristics, working principles, and applications of polarizers in various fields. The basic characteristic of a polarizer is its transparency: the polarizer only allows light waves along a specific vibration direction to pass through, while light waves in other directions are absorbed. This characteristic enables polarizers to effectively eliminate the effects of reflected and scattered light. Linear polarization: Most polarizers provide a linear polarization effect, which means they only allow light waves that vibrate within a specific angle range to pass through. This angle is commonly referred to as the “polarization angle”. Birefringence effect: Some high-quality polarizers have birefringence characteristics, that is, for different polarization states of light, the material will exhibit different refractive indices. This helps to improve image contrast and color saturation. The working principle of polarizers is that natural light contains all possible directional vibration electromagnetic field components, but in some cases, we need specific polarized light. For example, in LCD displays and photography, polarized light is necessary. The following is a brief explanation of how polarizers achieve this function: 1 Natural light: Unpolarized natural light contains all possible polarization states of vibration in both vertical and parallel directions of propagation. 2. Polarizer: When natural light passes through the first polarizer, only the vibration component parallel to the transmission axis of the polarizer can pass through. This produces polarized light. 3. Compensation film: In some special applications, such as LCD displays, compensation film is needed to adjust the polarization state of light to optimize the display effect. 4. Polarizer: The second polarizer serves as the polarizer, allowing only light that is in the same direction as its transmission direction to pass through. This can further filter out unnecessary polarized light. 5. Final result: After passing through two polarizers, only light in a specific polarization direction remains, which can be effectively used in various application scenarios. Polarizers are an indispensable part of LCD displays in various fields. Inside the LCD panel, the unpolarized natural light emitted by the backlight passes through a series of polarizers and layered structures, ultimately forming a visible image. The function of a polarizer is to ensure that each pixel can only emit light in a specific direction, thereby achieving the goal of controlling screen brightness. In addition, polarizers can reduce interference from external environmental light, improve the clarity and contrast of the image. In photography, polarizers are often used to reduce reflection on water surfaces and glass surfaces, as well as eliminate glare in the sky. Photographers can use the camera’s built-in polarizing lens or polarizing filter to achieve these effects. The polarizer can be rotated to the optimal position to adjust its polarization effect according to the angle of the subject being photographed. Sunglasses Polarized Sunglasses utilize the characteristics of polarizing lenses to reduce glare from water surfaces and road reflections. These reflected lights often contain strong horizontal polarization components, and polarized sunglasses reduce visual fatigue and protect the eyes from strong light by blocking this part of the light. As a precise optical component, polarizers are widely used in various fields and bring many conveniences to our lives. With the continuous advancement of technology, the development of new polarizing materials and the improvement of production processes will further expand the application range of polarizers, bringing us a better visual experience and quality of life.