Display Driver Overdrive Compensation for 3D Cross-Talk
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Solution Overview
Problem
Current display technologies face challenges in reducing cross-talk between sequential images, particularly in 3D displays, due to the slow temporal optical response of liquid crystal panels, leading to ghosting and image degradation, which affects the 3D experience and overall image quality.
Innovation Solution
A display drive apparatus that includes a receiver for sequential frames, a display controller to generate backlight intensity and transmittance drive values, and a compensator that introduces locally adapted overdrive compensation values to reduce cross-talk by accurately controlling transmittance elements, using a look-up table to determine these values based on the display position of transmittance elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the frame rate is increased to provide a smooth user experience, then the temporal resolution is improved, but the liquid crystal panel cannot complete the transmittance change within the available time due to its slow temporal optical response, resulting in cross-talk between sequential images
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing overdrive compensation values in a lookup table before displaying images. The compensator retrieves these pre-computed values based on current and previous transmittance values, allowing the system to compensate for the slow LC response without waiting for the response to complete, thus enabling high frame rates while maintaining image quality
Solution Approach 2:
The patent implements feedback by using the previous transmittance value (from the previous frame or field) together with the current desired transmittance value to determine the appropriate overdrive compensation. This feedback mechanism allows the system to dynamically adjust the drive signal based on the actual state of the LC panel, compensating for the slow response and preventing cross-talk between sequential images
2Device complexity
If a global overdrive value is used for all transmittance elements, then the device complexity is reduced, but the image quality deteriorates due to variations in response time across different display positions
Solution Approach 1:
The patent applies local quality by implementing position-dependent overdrive compensation. The compensator determines the display position of each transmittance element and selects appropriate overdrive compensation values from the lookup table based on that position. This allows different parts of the display to receive customized compensation values that match their specific response characteristics, improving overall image quality without requiring a overly complex system
Solution Approach 2:
The patent segments the display into different positional regions, with each region having its own characteristic response time and corresponding overdrive compensation values stored in the lookup table. This segmentation approach allows the system to handle position-dependent variations systematically, improving image quality across the entire display while maintaining manageable complexity through the use of a structured lookup table
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves image quality by reducing cross-talk, facilitating implementation, and providing more accurate control over light output, especially in 3D displays, while maintaining compatibility with existing systems.
Implementation Method 1
a transmittance panel (107) comprising a plurality of transmittance elements arranged in an array of lines and columns. Each of the transmittance elements (107a) may be controlled to provide a transmittance value... The temporal response for transmittance elements made of e.g. LC material
Implementation Method 2
the transmittance drive values may comprise a desired transmittance component and an overdrive component... a compensator (117) for introducing a locally adapted overdrive compensation value to the transmittance drive values
Implementation Method 3
a backlight (105) and a transmittance panel (107)... a backlight driver (111) for driving the backlight (105) in accordance with backlight intensity values
Data Source
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AI summary
A display driver drives a display (101) having a backlight (105) and a transmittance panel (107) comprising transmittance elements modulating the light from the backlight (105). The driver receives time sequential frames to be displayed. A controller (115) generates backlight intensity values for the backlight and transmittance drive values for the transmittance elements for the time sequential frames in response to image data for the time sequential frames and a global relationship between image data values and backlight intensity values and transmittance drive values. The transmittance drive values comprise a desired transmittance component and an overdrive component. A compensator (117) introduces a locally adapted overdrive compensation value to the transmittance drive values to generate compensated transmittance drive values and the backlight (105) is driven accordance with the backlight intensity values and the transmittance panel (107) is driven in accordance with the compensated transmittance drives values. The adaption may e.g. be for temperature variations or timing variations.