Dimming Methods of LCD Screens
LCD screens are widely used in various devices, and their dimming methods play a crucial role in optimizing visual experience and power consumption. There are mainly two common dimming methods for LCD screens: Pulse - Width Modulation (PWM) and Analog Dimming.
Pulse - Width Modulation is a popular dimming technique. It works by rapidly switching the backlight on and off. The duty cycle, which is the ratio of the on - time to the off - time, determines the average brightness of the backlight. When a lower brightness is required, the PWM controller reduces the on - time, thus decreasing the average power delivered to the backlight. For example, in a smartphone's LCD screen, when the ambient light is low, the PWM dimming system can adjust the backlight to a very low level, providing a comfortable viewing experience without straining the eyes. However, one drawback of PWM dimming is that at very low duty cycles, some users may perceive a flickering effect, which can cause eye fatigue over time.
Analog Dimming, on the other hand, adjusts the brightness by changing the voltage supplied to the backlight. By reducing the voltage, the intensity of the backlight is decreased proportionally. This method offers a more linear and flicker - free dimming experience. In applications where visual comfort is of utmost importance, such as in high - end monitors used for graphic design or video editing, analog dimming is often preferred. But analog dimming may have limitations in terms of power efficiency compared to PWM dimming, as it doesn't completely cut off the power during dimming but rather reduces the voltage continuously.
