Backlight Control for 3D Display Crosstalk Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Stereoscopic image display devices face challenges in reducing 3D crosstalk due to the response delay of liquid crystals, which causes brightness inconsistencies during frame periods, especially when using Black Data Insertion (BDI) methods.
Innovation Solution
A stereoscopic image display device with a liquid crystal display panel and a backlight unit divided into local dimming zones, where frame data is ordered to minimize brightness during reset frames and adjust local dimming values to target brightness levels for each eye's image data, using a frame rate conversion unit to insert black grayscale data between left and right eye image frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If Black Data Insertion (BDI) is used to reduce image tailing and motion blurring, then image quality improves, but 3D crosstalk increases due to liquid crystal response delay causing brightness inconsistencies
Solution Approach 1:
The backlight unit is divided into multiple local dimming zones that can be independently controlled. During reset frames, only specific zones are dimmed rather than the entire backlight, allowing selective brightness control to reduce crosstalk while maintaining image quality in other areas.
Solution Approach 2:
Different regions of the display have different backlight brightness levels during reset frames. The local dimming zones adjacent to the reset frame region are dimmed to minimum brightness, while other zones maintain their normal brightness levels, creating localized quality adjustment to address crosstalk specifically where needed.
2Reliability
If liquid crystal response time is increased to reduce tailing, then motion blurring decreases, but brightness inconsistency during frame periods worsens due to response delay
Solution Approach 1:
The backlight brightness is adjusted in advance during reset frames before the actual image data is displayed. By dimming the backlight to minimum brightness during the reset frame period, the system prepares the display state to prevent brightness carryover to the next frame, ensuring brightness consistency without requiring faster liquid crystal response.
Solution Approach 2:
The backlight brightness is periodically adjusted between minimum brightness during reset frames and normal brightness during image display frames. This periodic dimming and normal operation creates a rhythm that synchronizes with the frame structure, allowing the liquid crystal to fully respond during image frames while preventing residual brightness effects.
3Object-affected harmful factors
If local dimming zones are controlled to minimum brightness during reset frames, then 3D crosstalk is reduced, but overall energy consumption increases
Solution Approach 1:
Only specific local dimming zones are controlled to minimum brightness during reset frames, rather than dimming the entire backlight. This localized approach reduces crosstalk in the affected areas while maintaining normal brightness and energy efficiency in other display regions.
Solution Approach 2:
The backlight dimming is applied partially - only during reset frames and only in specific local zones - rather than continuously across the entire display. This partial application is sufficient to eliminate crosstalk while minimizing the energy penalty compared to full backlight dimming.
Data Source
AI summary
A stereoscopic image display device comprises a frame rate conversion unit that divides 3D input data into left eye image data and right eye image data, inserts reset frame data containing black grayscale data between the left eye image data and the right eye image data, and generates the (n+1)-th frame data to the (n+4)-th frame data containing the left eye image data, the black grayscale data, the right eye image data, respectively, and the black grayscale data, a look-up table that stores local dimming values used to control brightness for the overall local dimming zones to the minimum during the (n+2)-th and (n+4)-th frame periods, and local dimming values used to control brightness for each local dimming zone to target brightness during the (n+1)-th and (n+3)-th frame periods, and a backlight controller that controls light source brightness of the backlight unit for each local dimming zone.