Projector Illumination Pixel Control for Black Level Reduction
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Solution Overview
Problem
Achieving precise imaging in projectors with spatial modulators results in undesired increased black levels due to illumination of modulator pixels adjacent to those representing brightness, making it difficult to achieve a true black level in projected images.
Innovation Solution
A projector design where illumination pixels are only switched on when allocated image pixels are in the first state, with a threshold value set below the maximum representable brightness, ensuring that only image pixels representing black have an off-value, thereby minimizing background brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If precise imaging is achieved by allocating illumination pixels to image pixels, then image quality is improved, but black level increases due to illumination of adjacent modulator pixels
Solution Approach 1:
The patent applies local quality by differentiating the illumination state of pixels based on their spatial relationship to active image pixels. Specifically, pixels representing black areas are illuminated differently depending on whether they are adjacent to bright pixels or isolated, allowing localized control of background brightness to minimize black level elevation while maintaining imaging precision.
2Measurement precision
If illumination pixels are switched on for all image pixels above threshold, then brightness representation is improved, but background brightness increases
Solution Approach 1:
The patent implements local quality by applying different illumination strategies to different spatial regions. Pixels in isolated black areas receive different illumination treatment compared to pixels adjacent to bright regions, enabling accurate brightness representation while minimizing unnecessary background illumination.
Solution Approach 2:
The patent applies preliminary action by pre-classifying pixels into different categories (isolated black pixels vs. pixels adjacent to bright pixels) before illumination. This preliminary classification allows the system to optimize illumination patterns in advance, ensuring accurate brightness representation while minimizing background brightness elevation.
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 effectively reduces the black level in projected images, improving image quality, especially in dark environments like planetariums, by ensuring accurate representation of brightness values and minimizing residual illumination.
Implementation Method 1
a first spatial modulator (3) which is struck by the light (2) and has a plurality of illumination pixels (K1) which can, independently of one another, be brought into a first and into a second state
Implementation Method 2
imaging optics (4) with a magnification factor of +1, wherein the imaging optics (4) image the modulator pixels (K1, K2) of the first and second spatial modulators (3, 5) onto one another
Implementation Method 3
a second spatial modulator (5) which has a plurality of image pixels (K2) which can, independently of one another, be brought into a first and into a second state and with which the image to be projected is generated
Data Source
AI summary
A projector having an illumination modulator to modulate the intensity of the light in a pixel-individual manner, a projection lens projecting the light being modulated in a pixel-individual manner onto an image modulator to generate the image to be projected such that each illumination pixel is associated with at least one image pixel. A controller which generates illumination control data and generates image control data for the image modulator. The illumination control data are generated such that they have an on-value for each illumination pixel that is associated with at least one image pixel intended to represent a brightness value in the image that exceeds a predetermined threshold value according to the image data, said on-value selected such that each illumination pixel being associated with at least one image pixel intended to represent a brightness value according to the image data that exceeds a predetermined threshold value and falls short of a predetermined maximum value, is also at least temporarily switched to the second state during periods when the at least one associated image pixel is switched to the second state.