LCD Contrast & High Contrast LCD
LCD contrast or contrast ratio is a main property of LCD display. It is the ratio of the brightest white state to the darkest black state, that a LCD can produce. For monochrome LCD, high contrast means clear display, more grey scale level. As for high contrast TFT LCD, it means vivid color and sharp image.
Different applications have different requirements on LCD contrast. For normal use case, 300:1 ~ 400:1 contrast ratio is about right. As for medical LCD display, 600:1 ~ 1000:1 is typical requirement. So that we can have more gray scale or color levels to represent more information. But how do we create high contrast LCD?
Change LCD Design
Different LCD panel type has its own advantages and shortcomings. In term of LCD contrast, TN type LCD display has the lowest contrast ratio. While as IPS and VA types LCD, they provide a lot higher contrast. When possible, designing LCD with low driving multiplex (duty ratio) brings better contrast ratio. Static driving LCD has the best contrast.
Optimize LCD Driving Voltage
This is the most economic way to create high contrast LCD. Optimizing LCD driving voltage is a process of compromising. We know different viewing angels require different driving voltages. But if the voltage is too low, the LCD display is dim. When the driving voltage is too high, ghosting shows up. Therefore, we need to fix LCD viewing angle, first before optimizing LCD driving voltage to get the best possible contrast.
Use Better Polarizer
High efficient LCD polarizer provides better contrast. For negative LCD, the effect is especially obvious. Polarizer efficiency improves from 98% to 99.5%, negative LCD value contrast could increase from 45 to 1000. As for positive LCD, value contrast increases from 7 to 10. LCD without back light will require more reflective polarizer to gain better contrast. On the other hand, LCD display using back light needs more transmissive polarizers to produce higher contrast image.
Topway has been working in LCD industry for more than 20 years. We are confident to supply you LCD display with the best contrast.