Filterless LCD Contrast Enhancement for HDR Displays
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Solution Overview
Problem
Commercially available High Dynamic Range (HDR) displays face challenges in reproducing starfields and other challenging images due to parallax, backlight leakage, and artifacts such as moiré patterns, which affect their spatially localized contrast and overall image fidelity.
Innovation Solution
The implementation of a dual-modulation HDR display system comprising a color LCD panel for image generation and an LCD panel without color filters for contrast improvement, with a controller that energizes both panels using feedback and control data to enhance contrast and brightness fidelity, and the use of diffusers to smooth light and prevent high-frequency artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If local dimming of the backlight is used to improve contrast ratio, then the dynamic range increases, but artifacts such as moiré patterns and backlight leakage occur
Solution Approach 1:
The display system is divided into two separate LCD panels: a color LCD panel for image generation and a monochrome LCD panel for contrast enhancement. This segmentation allows each panel to perform its specific function optimally without the interference that causes moiré patterns in single-panel systems.
Solution Approach 2:
The monochrome LCD panel acts as an intermediary layer between the backlight and the color LCD panel. It modulates the backlight intensity locally before light reaches the color panel, preventing backlight leakage and improving contrast without creating artifacts.
2Illumination intensity
If multiple registered modulating layers are used to improve contrast, then the black levels are enhanced, but the device complexity increases
Solution Approach 1:
The patent combines a color LCD panel and a monochrome LCD panel into a single integrated display system with a shared backlight. This merging approach achieves the contrast enhancement of multiple layers while reducing overall system complexity compared to stacking separate modulating layers.
Solution Approach 2:
The monochrome LCD panel serves multiple functions: it acts as a local dimming layer, a contrast enhancement filter, and a brightness regulator. This multi-functionality reduces the need for additional separate components, simplifying the overall device structure.
3Measurement precision
If higher resolution is used in the contrast-improving panel, then the image fidelity increases, but the manufacturing precision requirements increase
Solution Approach 1:
The system allows the monochrome panel to have higher resolution specifically in the contrast-critical regions, while the color panel maintains standard resolution. This local quality approach improves image fidelity where needed without requiring uniform high precision across the entire system.
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
This solution significantly improves spatially localized contrast and image fidelity, reducing parallax and artifacts, and enables the creation of high dynamic range displays that can effectively reproduce challenging images with increased resolution and accuracy.
Implementation Method 1
a first LCD panel for generating an image and a second LCD panel without color filters for increasing contrast and resolution
Implementation Method 2
The contrast-improving panel may operate in combination with an analyzing polarizer
Implementation Method 3
The display may include, for example, a set of diffusers, including a relatively coarse diffuser configured to diffuse light from a backlight of the display
Data Source
AI summary
A display provides increased contrast and resolution via first LCD panel energized to generate an image and a second LCD panel configured to increase contrast of the image. The second panel is an LCD panel without color filters and is configured to increase contrast by decreasing black levels of dark portions of images (making them blacker or darker) using polarization rotation and filtration. Preferably, the second LCD panel is of higher resolution than the first LCD panel. The panels may be directly illuminated or edge lit, and may be globally or locally dimmed monochrome or multi primary lights that may also include individual control of color intensities for each image or frame displayed. The panels may be placed in any order, but preferably are arranged such that active layers in each panel are as close together as possible. Brightness is maintained by the combination of reusing polarization between the panels and by not going through more than one set of color filters. Improved contrast is a result of using multiple light modulators in series.