Display Light Adjustment for Halo Effect Reduction
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Solution Overview
Problem
Display devices with local dimming functions experience 'black floating' or 'halo effect' where high-luminance areas inadvertently brighten adjacent low-luminance areas, reducing contrast and failing to effectively mitigate the halo effect.
Innovation Solution
A display device with a light source device comprising multiple light sources for divided areas and a signal processor that calculates and adjusts light quantities for each area based on image signals, specifically reducing light in areas adjacent to those with lower light quantities to minimize the halo effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If light sources in high-luminance areas are reduced to prevent black floating, then the halo effect is reduced, but contrast to high-luminance areas is reduced
Solution Approach 1:
The patent applies local quality by adjusting the light quantity of light sources based on their specific position relative to high-luminance areas. Light sources adjacent to high-luminance areas are identified and adjusted with a different light quantity than those not adjacent, allowing selective mitigation of black floating while preserving contrast in non-adjacent areas.
Solution Approach 2:
The patent segments the light source array into different groups based on their spatial relationship with high-luminance areas. By dividing light sources into those adjacent to high-luminance areas and those not adjacent, the system can apply different light quantity adjustments to each segment, resolving the contradiction between reducing black floating and maintaining overall contrast.
2Object-affected harmful factors
If light sources in low-luminance areas are adjusted to reduce uncomfortable impression, then visual comfort is improved, but contrast to high-luminance areas is reduced
Solution Approach 1:
The patent applies local quality by adjusting only the light sources that are adjacent to high-luminance areas, rather than uniformly adjusting all light sources in low-luminance areas. This selective approach addresses the uncomfortable impression locally where it occurs due to the halo effect, while preserving contrast in other areas.
3Use of energy by moving object
If local dimming is applied to control light emission for each divided area, then energy efficiency is improved, but black floating occurs in adjacent areas
Solution Approach 1:
The patent applies preliminary anti-action by proactively adjusting the light quantity of light sources adjacent to high-luminance areas before the black floating phenomenon fully manifests. By identifying and adjusting these specific light sources in advance, the system prevents the halo effect from occurring while maintaining the energy efficiency benefits of local dimming.
Solution Approach 2:
The patent applies parameter changes by dynamically modifying the light quantity parameter of specific light sources based on the luminance characteristics of adjacent display areas. This allows the system to adapt light emission parameters in real-time to prevent black floating while maintaining energy efficiency through selective adjustment.
Data Source
AI summary
According to an aspect, a display device includes: an image display panel having an image display surface on which display is to be controlled based on an image signal; a light source device that includes light sources provided corresponding to divided partial areas of the image display surface, and is configured to illuminate the image display surface; and a signal processor configured to calculate a light quantity of each light source for each of the partial areas. The signal processor is configured to calculate the light quantity for each partial area based on the image signal, set one of the partial areas as an adjustment target partial area for the light quantity, and adjust the light quantity in the adjustment target partial area when the light quantity of an adjacent partial area located around the adjustment target partial area is equal to or smaller than a predetermined value.