Backlight Luminance Control for Liquid Crystal Display Flicker
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Solution Overview
Problem
Combining active backlight driving and suspension driving in liquid crystal display devices leads to issues such as a dark display due to backlight shutdown during suspension periods and image flicker caused by luminance changes, which deteriorate display quality.
Innovation Solution
A display device configuration that includes a light source, a light source luminance controlling section, a display controlling section, a suspension controlling section, a light source control parameter calculating section, and a light source control parameter supplying section, which calculates and supplies light source control parameters based on gray scale information to maintain consistent luminance during suspension periods, preventing flicker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If suspension driving is implemented to reduce power consumption, then power consumption is reduced, but the backlight emits no light during suspension time period causing display to become dark
Solution Approach 1:
The patent segments the display device into different driving modes: normal driving mode where both display panel and backlight are active, and suspension driving mode where the display panel is suspended but the backlight remains active. This segmentation allows the system to reduce power consumption by suspending the display panel while maintaining backlight operation, thus resolving the contradiction between power consumption reduction and display quality maintenance.
2Illumination intensity
If backlight luminance is controlled in accordance with input image during suspension period, then display quality is improved, but no input image is newly inputted during suspension time period so luminance cannot be properly controlled causing flicker
Solution Approach 1:
The patent applies preliminary action by calculating the backlight control parameter before the suspension period starts and storing it in a buffer. During the suspension period, the stored parameter is used to control the backlight luminance, ensuring smooth transition and preventing flicker. This preliminary calculation and storage of control parameters allows the system to maintain proper luminance control even when no new input images are available during suspension.
3Stability of the object's composition
If identical image continues to be displayed from driving time period to suspension time period, then image continuity is maintained, but image flickers due to luminance change at transition
Solution Approach 1:
The patent uses preliminary action by pre-calculating and buffering the backlight control parameter before suspension. This ensures that the backlight luminance remains consistent with the displayed image during the transition from driving to suspension period, preventing flicker while maintaining image continuity.
Solution Approach 2:
The patent introduces an intermediary mechanism (buffer storage) that bridges the driving period and suspension period. The buffer stores the backlight control parameter and supplies it during suspension, acting as a mediator that maintains luminance consistency and prevents flicker during the transition between different operating states.
Data Source
AI summary
A display device of the present invention includes (i) a BL control parameter calculating section (224) for calculating a BL control parameter on the basis of an input image, (ii) a BL luminance control signal generating block (230) for generating a BL luminance control signal on the basis of the BL control parameter and (iii) an output section (225) for supplying, to the BL luminance control signal generating block (230), a BL control parameter that has been calculated by the BL control parameter calculating section (224) immediately before a suspension time period during which a display controlling section is being suspended.