Display Control Substrate Correcting Color Shifts During Luminance Transitions
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Solution Overview
Problem
Existing liquid crystal display devices struggle to accurately correct color levels when luminance changes suddenly, particularly from 100% to 10%, due to the slow response speed of certain phosphors, leading to noticeable color shifts and reddish residues.
Innovation Solution
A display device configuration that includes a display panel, an illumination device with a light source and control substrate, which detects changes in luminance using a detection circuit and corrects display data using a display data correction circuit, specifically addressing the response speeds of different phosphors to maintain color accuracy during rapid luminance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a red phosphor with slow response speed is used to achieve excellent color reproducibility and luminance, then color quality is improved, but color level stability deteriorates during luminance transitions
Solution Approach 1:
The system performs preliminary detection of luminance light modulation data changes and proactively corrects display data before the color level shift occurs. By detecting the luminance transition in advance and applying correction coefficients ahead of time, the system prevents the color level instability that would otherwise occur during luminance transitions, particularly when using slow-response phosphors for high luminance performance
Solution Approach 2:
The system establishes a feedback loop where the detection circuit continuously monitors luminance light modulation data, compares it against reference values, and automatically adjusts display data through correction coefficients. This closed-loop feedback mechanism compensates for the slow response speed of red phosphors by dynamically adjusting display parameters based on real-time luminance detection, thereby maintaining color level stability during transitions
2Use of energy by moving object
If luminance is changed rapidly from 100% to 10%, then power consumption is reduced, but color level accuracy deteriorates due to phosphor response delay
Solution Approach 1:
When rapid luminance reduction is detected, the system applies preliminary correction to display data using pre-calculated correction coefficients that account for the expected phosphor response delay. This allows the system to maintain color accuracy even when transitioning from 100% to 10% luminance, preventing the reddish residue that would normally occur during such rapid transitions
Solution Approach 2:
The system dynamically changes display parameters (gray scale values) based on detected luminance transitions. By applying correction coefficients that modify the relationship between input image data and actual display output, the system compensates for phosphor response delays during rapid luminance changes, maintaining color accuracy while enabling aggressive power management transitions
3Measurement precision
If conventional gain control signals are used for steady-state color correction, then color accuracy is maintained at stable luminance, but transient color shifts cannot be corrected
Solution Approach 1:
The system transitions from static gain control to dynamic correction by continuously detecting luminance light modulation data and applying time-varying correction coefficients. This dynamic approach allows the system to adapt to both steady-state conditions and transient luminance changes, providing color accuracy across all operating conditions rather than only at stable luminance levels
Solution Approach 2:
By implementing continuous feedback detection of luminance transitions and real-time adjustment of display data with correction coefficients, the system extends color correction capability from steady-state only to include transient responses. The feedback mechanism detects when luminance changes occur and automatically applies appropriate corrections, making the system adaptable to both stable and changing luminance conditions
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
The solution effectively suppresses color level changes caused by luminance variations, ensuring accurate color reproduction and preventing reddish residues by adjusting the gray scale values of pixels based on the response speeds of red and green phosphors during PWM light modulation.
Implementation Method 1
a blue LED element
Implementation Method 2
a red phosphor and a green phosphor emitting light by excitation light (blue light) of the blue LED element
Data Source
AI summary
A display device includes a display panel in which display pixels including colored pixels of a plurality of colors are arranged, an illumination device including a light source and configured to illuminate the display panel with light, and a control substrate configured to control drive of the display pixels, wherein the control substrate includes a display data generation circuit configured to generate display data for driving the display pixels, based on image data supplied from an external image signal supply source, a detection circuit configured to detect a change in luminance light modulation data for modulating luminance of the light source, supplied from an external image signal supply source, and a display data correction circuit configured to correct the display data, based on an output value of the detection circuit.