Display Device Local Dimming Luminance Uniformity Correction
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Solution Overview
Problem
Display devices with local dimming functions often exhibit visual differences in output luminance due to intensity variations between adjacent light emitting regions, leading to uneven display quality, especially when attempting to maintain consistent luminance across adjacent areas.
Innovation Solution
A reflective display device with a measurement unit to assess external light intensity and a control unit that adjusts internal light intensity and pixel gradation values to minimize luminance differences between adjacent regions by compensating for intensity disparities between light emitting regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If local dimming function is used to adjust light intensity for each light emitting region, then display output intensity can be controlled locally, but visual differences in luminance appear between adjacent regions
Solution Approach 1:
The patent applies local quality by differentiating the treatment of pixels at boundaries between partial regions versus pixels within regions. Specifically, pixels located at boundaries receive corrected gradation values to compensate for luminance differences caused by adjacent light emitting regions with different light intensities, while non-boundary pixels use standard gradation values. This localized correction approach maintains the benefits of local dimming while eliminating visible luminance discrepancies at region boundaries.
Solution Approach 2:
The patent changes the gradation parameter for pixels at boundaries between partial regions. When a pixel is identified as being at a boundary between two partial regions corresponding to light emitting regions with different light intensities, the control unit adjusts the gradation value to compensate for the expected luminance difference. This parameter adjustment ensures that pixels displaying identical luminance values appear visually consistent across region boundaries, resolving the luminance uniformity issue while preserving local dimming functionality.
2Manufacturing precision
If identical luminance is displayed across adjacent partial regions, then visual uniformity is achieved, but differences in light intensity between light emitting regions cause perceptible variations
Solution Approach 1:
The patent implements preliminary action by pre-identifying pixels that are located at boundaries between partial regions before displaying the image. The control unit determines which pixels require correction based on their positional relationship with light emitting regions having different light intensities. This preliminary identification and correction process occurs before the actual display output, allowing the system to automatically compensate for luminance differences without requiring complex real-time adjustments or user intervention, thus maintaining ease of operation while achieving luminance consistency.
Data Source
AI summary
According to an aspect, a display device includes a display unit, an illumination unit, a measurement unit, and a control unit. When pixels that are expected to perform display output at identical luminance are adjacent to each other in adjacent partial regions, and when a difference in the intensity of the internal light between light emitting regions corresponding to the adjacent partial regions is equal to or larger than a predetermined threshold, the control unit performs correction to increase luminance of a predetermined number of pixels belonging to a first partial region corresponding to a first light emitting region the intensity of the internal light from which is lower among the adjacent partial regions. The predetermined number of pixels are located closer to a second partial region corresponding to a second light emitting region the intensity of the internal light from which is higher among the adjacent partial regions.