Font Size: a A A

The Studying Of Special Electro-optical Properties Of Liquid Crystal Light Valve

Posted on:2008-08-22Degree:MasterType:Thesis
Country:ChinaCandidate:J LiuFull Text:PDF
GTID:2178360215467275Subject:Materials Physics and Chemistry
Abstract/Summary:PDF Full Text Request
Liquid crystal is the dielectric anisotropy and conductance anisotropy. External electricfield or magnetic field makes liquid crystal molecules change, so is optical modulated. LiquidCrystal Display (LCD) is the use of these characteristics and developed. It has low powerconsumption, good optical properties, longevity advantages, but it also has serious disadvantage:not good temperature characteristics. As the liquid crystal material's physical properties affectedby the temperature is very great. Liquid crystal in a very cold situation will gradually become agenuine crystal in the case of overheating will be isotropic material or pure liquid. This make thecharacters or graphics distortion with the substrate in a high temperature, the substrate is black,clarity declined; while at low temperature lags behind its shows, it will also affect its clarity.Thus environmental temperature affects the LCD very great. The paper studies of theenvironmental temperature effects LCLV special electro-optical properties. Also researchelectro-optical properties of LCLV driven by the frequency and voltage.Study found that the threshold voltage and saturation voltage of LCLV are a function oftemperature. With the rise of temperature threshold voltage and saturation voltage are reduced.This is due to in the lower temperature liquid crystal materials become viscosity, molecularmovement needs more energy, liquid crystal with the same voltage at room temperature isdifficult to rotate. So increased the actuation voltage, the liquid crystal molecules can acceleratethe campaign to reach the display. Steepness factor also change with the temperature. The higheris the temperature, the greater is the steepness factor. The greater is the steepness factor, thesmaller amount LCLV display. When the temperature drops, the response time of LCLV grow.And the change of falling time tfis slower than the rising time tr. At 0℃or lower, the imagebegin to delay, and below -15℃the image is not accepted. The way that starts the LCD at lowtemperature is improve the LCD temperature atmosphere, which create a small temperature fieldaround the LCD, no matter what kind of low-temperature conditions, always provide anappropriate small temperature environment in which the LCD can normally work.The study also found that the threshold voltage and the saturation voltage are raised whenthe frequency increases, and its steepness factor in the 100Hz achieve minimum. But thefrequency of LCLV affect the response time little. However, the frequency is too low or too high will affect the display of the LCD, so under normal circumstances LCD driver frequency is100Hz.The conclusions of the paper provide a basis for using and enhancing its stability anddisplay information capacity under the condition that the environmental temperature is greatlychanged, which have practical value.
Keywords/Search Tags:liquid crystal light valve, electro-optical properties, temperature, frequency, voltage
PDF Full Text Request
Related items