The polarization principle of liquid crystal displays can be briefly summarized as the following key points in high school: 1. The polarization basis of light
Definition of polarized light: Light is an electromagnetic wave with polarization properties. When the vibration direction of light is asymmetric to the propagation direction, it is called polarized light. Polarized light is divided into plane polarized light (linearly polarized light), circularly polarized light, and elliptically polarized light.
Natural light and polarized light: Natural light vibrates uniformly in all directions in space, without a specific polarization direction. Polarized light, on the other hand, has a definite vibration direction. 2、 Characteristics of Liquid Crystal Molecules
Liquid crystal molecular structure: Liquid crystal is composed of a special organic compound with a long and thin molecular structure. Under specific conditions, liquid crystal molecules can exhibit ordered arrangement.
Electric field effect: Liquid crystal molecules exhibit disordered arrangement without the action of an electric field, and cannot produce polarization effect on light. But when an electric field acts on liquid crystal molecules, they will undergo orientation and exhibit an ordered arrangement, thereby changing the polarization direction of light. 3、 Polarization principle of LCD display
Polarizers and Liquid Crystal Layers: Liquid crystal displays typically consist of two parallel polarizers (polarizing films) and a liquid crystal layer. The first polarizer (polarizer) converts natural light into polarized light, with its vibration direction perpendicular to the direction of the polarizer.
Electric field regulation: When polarized light passes through the liquid crystal layer, the arrangement of liquid crystal molecules is affected by the electric field. If there is no electric field, liquid crystal molecules will rotate the polarization direction of light by 90 degrees to match the direction of the second polarizer (analyzer), and the light can pass through the analyzer to display brightness. However, when an electric field acts on liquid crystal molecules, they no longer rotate the polarization direction of light, causing the light to be unable to pass through the analyzer and appear dim.
Image display: By controlling the electric field on the LCD screen, the rotation angle of liquid crystal molecules can be adjusted to control the transmission or obstruction of light. In this way, the LCD display can display different images according to the changes in the electric field. 4、 Summary
The polarization principle of liquid crystal displays is to use the orientation change of liquid crystal molecules under the action of an electric field to change the polarization direction of light, thereby controlling the transmission or obstruction of light. By adjusting the electric field strength, image display and brightness adjustment can be achieved. This principle not only makes LCD displays efficient and energy-saving, but also provides a foundation for their widespread application in electronic products. In high school, understanding this principle helps students better grasp the basic knowledge of optics and electronics.