LCD Backlight Lamp Timing for Ghost Reduction
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Solution Overview
Problem
Liquid crystal display (LCD) devices face challenges in displaying clear moving pictures due to temperature differences across the backlight unit, leading to ghost phenomena and image quality deterioration, as different regions of the LCD panel have varying liquid crystal response times.
Innovation Solution
The solution involves adjusting the on/off-time intervals of lamps in the backlight unit to compensate for temperature differences across the LCD panel, using a lamp driving unit with an inverter circuit and IC chip to control lamp timing based on temperature and pixel operation, effectively mimicking an impulse driving method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a hold type light source is used in LCD, then power consumption is reduced and device is slimmed, but moving picture quality deteriorates due to motion blurring
Solution Approach 1:
The patent applies periodic action by sequentially turning on and off multiple linear lamps in the backlight unit at different time intervals. This creates a scanning effect where each lamp illuminates the screen for a brief period, then turns off before the next lamp activates. This periodic illumination pattern reduces motion blurring while maintaining lower power consumption compared to continuous illumination, thus resolving the contradiction between power efficiency and moving picture quality.
2Device complexity
If linear lamps are used in backlight unit, then device structure is simplified, but temperature differences cause ghost phenomenon and image quality deterioration
Solution Approach 1:
The patent segments the backlight unit into multiple independent linear lamps arranged in sequence rather than using a single continuous light source. Each lamp can be controlled independently with different on/off timing. This segmentation allows the system to maintain the structural simplicity of linear lamps while compensating for temperature-induced ghost phenomena through differential timing control, thus resolving the contradiction between structural simplicity and image quality.
Solution Approach 2:
The patent applies local quality by assigning different on/off time intervals to different lamps based on their position in the backlight unit. Lamps in different regions operate with locally optimized timing parameters to compensate for temperature variations in their respective zones. This local differentiation eliminates ghost phenomena caused by uniform temperature distribution while maintaining the overall simplicity of the linear lamp structure.
3Reliability
If multiple lamps are sequentially driven, then moving picture clarity is improved, but ghost phenomenon occurs due to temperature differences across the panel
Solution Approach 1:
The patent applies dynamics by making the on/off time intervals of the lamps variable rather than uniform. Each lamp is assigned a specific time interval based on its position and the temperature characteristics of its corresponding region in the LCD panel. This dynamic timing adjustment compensates for temperature-induced response time variations, reducing ghost phenomena while maintaining moving picture clarity.
Solution Approach 2:
The patent changes the temporal parameter (on/off time interval) of each lamp to compensate for temperature differences across the panel. By adjusting the duration and timing of each lamp's operation, the system compensates for the varying liquid crystal response times caused by temperature gradients, thereby reducing ghost phenomena while preserving moving picture clarity.
Data Source
AI summary
A method for driving a liquid crystal display device is provided. The liquid crystal display device includes a liquid crystal panel and a plurality of lamps. The method includes: sequentially driving the plurality of lamps to supply light to the liquid crystal panel, at least one of the lamps having a different on-time interval from another one of the lamps.