Projector Illumination Control for Edge Pixel Brightness Uniformity
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Solution Overview
Problem
Existing projectors face challenges in achieving precise pixel-accurate imaging, leading to undesired brightness fluctuations and color aberrations due to chromatic errors in imaging optics, especially when projecting multicolored images with rapid succession of color subframes.
Innovation Solution
A projector design where each illumination pixel is allocated to precisely one image pixel, with illumination control data ensuring that pixels representing brightness values above a threshold are uniformly illuminated, and adjacent pixels are also illuminated to match the intensity of fully surrounded bright pixels, reducing background brightness and color artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel-accurate imaging is attempted with imaging optics, then the black level can be reduced, but brightness fluctuations occur at edge pixels due to chromatic errors
Solution Approach 1:
The patent applies local quality by differentiating the illumination control for different pixel types. Edge pixels (those adjacent to bright pixels) receive different illumination control compared to interior pixels. Specifically, edge pixels are illuminated even when their corresponding image pixels should be black, to compensate for the brightness loss caused by chromatic aberration. This localized adjustment ensures uniform brightness across the image without requiring perfect pixel-accurate imaging.
2Reliability
If chromatic errors in imaging optics are present, then color aberrations occur in multicolored images, but correcting them would require complex optical systems
Solution Approach 1:
The patent replaces complex optical correction mechanisms with a digital control approach. Instead of designing complex optical systems to correct chromatic aberrations, the invention uses digital signal processing and illumination control to compensate for the optical defects. The control unit adjusts the illumination of individual pixels based on their spatial relationship with bright pixels, effectively correcting color aberrations through software rather than hardware.
3Productivity
If rapid succession of color subframes is used, then temporal superimposition is achieved, but brightness fluctuations cause color aberrations
Solution Approach 1:
The patent applies preliminary action by pre-calculating the illumination control data before the actual image projection. The control unit determines which pixels should be illuminated based on the image data and the spatial relationships between pixels, creating illumination control data in advance. This pre-computed control information ensures that when color subframes are displayed in rapid succession, the brightness fluctuations are already compensated for, maintaining color accuracy without reducing frame rate.
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 approach ensures uniform illumination of edge pixels and reduces the black level in projected images, minimizing brightness fluctuations and color aberrations, resulting in a more accurate and stable image projection.
Implementation Method 1
imaging optics (in particular pixel-accurate) with which the first modulator is imaged onto the second modulator
Data Source
AI summary
A projector, having an illumination modulator having multiple illumination pixels a projection lens projecting the light being modulated in a pixel-individual manner onto an image modulator having multiple image pixels to generate the image. A controller generates illumination control data for the illumination modulator and generates image control data for the image modulator. The illumination control data has either an on-value or an off-value The illumination control data (MS) is generated such that the on-value for each illumination pixel is associated with at least one image pixel that is to represent a brightness value within the image and an off-value for all other illumination pixels, with the exception that the illumination control data for at least one of the other illumination pixels that is at a distance by not more than one predetermined pixel number, has an on-value.