Multiple Projector 3D Cinema System for Uniform Illumination
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Solution Overview
Problem
Highly directive screens used in 3D cinema applications suffer from hot spotting and non-uniform illumination, particularly at oblique viewing angles, limiting their use due to reduced brightness and inconsistent image quality across the audience.
Innovation Solution
The use of multiple projectors placed at the edges of the auditorium, combined with screens having controlled directivity, allows for higher gain screens (up to 3.0) while maintaining uniformity by reducing crosstalk and trapezoidal distortion, and improving illumination angles for better viewing experiences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If highly directive screens are used in 3D cinema applications, then polarization is preserved and 3D effect is maintained, but hot spotting and non-uniform illumination occur particularly at oblique viewing angles
Solution Approach 1:
The patent divides the projection system into multiple projectors positioned at different locations (front, sides, or rear of the auditorium). Each projector contributes to illuminating different portions of the screen, segmenting the illumination task to achieve uniform coverage across the entire screen surface while maintaining polarization preservation through the highly directive screen.
Solution Approach 2:
The patent employs screens with spatially varying directivity characteristics, where different regions of the screen have optimized reflection properties for their specific viewing angles. This allows each local area of the screen to maintain appropriate polarization preservation while contributing to overall uniform illumination across the screen.
2Reliability
If highly directive screens are used, then polarization is preserved, but brightness is reduced and image quality becomes inconsistent across the audience
Solution Approach 1:
By using multiple projectors positioned at different locations, the system segments the illumination task to ensure that each viewer position receives adequate brightness from at least one projector. This segmentation approach maintains polarization preservation while compensating for the brightness reduction inherent in highly directive screens through distributed illumination.
Solution Approach 2:
The patent transitions from a single-point illumination source to a distributed spatial arrangement of multiple projectors. This dimensional change in the projection system architecture allows the system to maintain polarization preservation while significantly improving overall brightness and image quality consistency across different audience positions.
3Illumination intensity
If multiple projectors are placed at the edges of the auditorium, then uniformity and brightness are enhanced, but device complexity increases
Solution Approach 1:
The patent segments the projection system into multiple independent projectors positioned at the edges of the auditorium. Each projector handles a specific portion of the screen illumination, dividing the complex task of achieving uniform illumination across the entire screen into manageable segments that can be independently optimized.
Solution Approach 2:
By positioning projectors at specific edge locations rather than using a single central projector, the system optimizes the illumination quality for different local regions of the screen and audience areas. This localized approach improves uniformity while the modular nature of multiple identical projectors actually reduces overall system complexity compared to a single complex projector 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 configuration enhances overall brightness and uniformity across the screen, reducing hot spotting and improving the 3D effect by achieving higher gains and smaller reflection angles, especially at edge seating positions, thus providing a more consistent viewing experience.
Implementation Method 1
The directivity of a screen relates to the amount or angle of specular reflection of light from the screen
Implementation Method 2
In some 3D applications, such as polarization based systems, screens with high directivity are utilized because they have the capability of preserving polarization when light is reflected off the screen
Implementation Method 3
Spectral separation provides separation at the projector by filtering the left and right eye spectrally
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A theater utilizes multiple projectors that are widely spaced. The wide spacing of the projectors reduces hot spotting that occurs on flat, curved, retro-reflective, and other types of screens. The projectors are spaced widely apart and generally are placed at opposite sides of the theater. The wide spacing causes a trapezoidal distortion or effect which may be electronically compensated for by, for example, changing pixel locations on modulators of the projectors such that same (or corresponding) pixels modulated in both projectors are ultimately projected onto a same pixel area of the screen. The invention is particularly advantageous in polarization based 3D systems which generally require high directivity screens where hot spotting and related crosstalk are common.