Display Device Luminance Correction for Grayscale Accuracy
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Solution Overview
Problem
Display quality deteriorates after dimming due to luminance sag and bit loss in existing display devices, where the grayscale values are not accurately maintained during dimming operations.
Innovation Solution
A display device and driving method that include a luminance correction unit, gamma correction unit, and gamma voltage generator, which correct input data based on a dimming code value, update voltage code values to maintain accurate grayscale representation by comparing the highest dimming grayscale value with a reference value and adjusting gamma voltages accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If dimming is applied to reduce luminance, then power consumption is reduced, but display quality deteriorates due to luminance sag and bit loss
Solution Approach 1:
The patent changes the voltage code value parameter dynamically based on the dimming code value. When dimming is applied, the system updates the voltage code value to compensate for luminance sag, thereby maintaining display quality while reducing power consumption. This parameter adjustment ensures that the gamma voltage generator produces appropriate voltage levels even under dimming conditions.
Solution Approach 2:
The patent implements a feedback mechanism where the controller compares the highest dimming grayscale value with a preset highest reference grayscale value. Based on this comparison, the controller determines whether to update the voltage code value, creating a closed-loop control system that maintains display quality during dimming operations.
2Illumination intensity
If dimming code value is increased to reduce luminance, then brightness is reduced, but grayscale accuracy is lost due to bit loss
Solution Approach 1:
The patent dynamically adjusts the voltage code value parameter in response to changes in dimming code value. This parameter change compensates for the loss of grayscale accuracy by updating the reference voltage levels used in gamma correction, thereby maintaining precise grayscale representation even at reduced brightness levels.
Solution Approach 2:
The patent performs preliminary comparison of the highest dimming grayscale value with the reference grayscale value before actual display output. This preliminary action allows the system to proactively update the voltage code value to prevent grayscale accuracy loss, rather than correcting it after the fact.
3Manufacturing precision
If voltage code value is updated to maintain grayscale accuracy, then display quality is improved, but system complexity increases
Solution Approach 1:
The controller performs multiple functions: it manages dimming operations, compares grayscale values, determines voltage code updates, and coordinates with the gamma voltage generator. By consolidating these functions in a single controller, the patent avoids adding separate dedicated circuits for each function, thereby limiting the increase in system complexity while still achieving improved display quality.
4Manufacturing precision
If gamma voltages are adjusted to compensate for luminance sag, then display quality is maintained, but control complexity increases
Solution Approach 1:
The patent simplifies gamma voltage adjustment by changing only the voltage code value parameter rather than directly modifying multiple gamma voltage levels. This single parameter change propagates through the gamma voltage generator to adjust all necessary voltage levels, reducing control complexity while maintaining display quality compensation for luminance sag.
Data Source
AI summary
A display device includes a luminance correction unit that corrects input data based on a dimming code value and outputs correction data, a gamma correction unit that corrects the correction data and generates output data, a gamma voltage generator that generates gamma voltages depending on a first voltage code value, a data driver that converts the output data into data voltages based on the gamma voltages, and a controller that supplies the dimming code value and the input data to the luminance correction unit and provides the first voltage code value to the gamma voltage generator. The controller compares a highest dimming compares a highest dimming grayscale value of the output data determined by the dimming code value with a highest reference grayscale value and updates the first voltage code value with a second voltage code value.