Relay Lens Spherical Aberration for High Dynamic Range Projectors
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Solution Overview
Problem
High dynamic range projectors face challenges in achieving optimized high dynamic range and contrast due to the simple blurring of light between light modulators, which does not effectively utilize the potential of the relay lens system.
Innovation Solution
The relay lens system introduces a controlled spherical aberration into the light between the first and second light modulators, altering the shape of pixels from square to Gaussian or pseudo-Gaussian, with a broad central region and a tail extending over multiple pixels, using a combination of numerical aperture and lens configurations to suppress local maxima, minima, and derivative zeros in the ray fan plot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a relay lens system simply blurs light between light modulators, then the system structure is simple, but the high dynamic range and contrast are not optimized
Solution Approach 1:
The patent introduces controlled spherical aberration as an optical parameter change in the relay lens system. By deliberately introducing third-order spherical aberration and suppressing higher-order aberrations (fifth and seventh order), the system transforms the point spread function from a simple blur to a controlled Gaussian-like distribution with a broad central region and extended tail, thereby optimizing illumination intensity distribution for high dynamic range projection
Solution Approach 2:
The patent employs dynamic control of the aperture stop to adjust the numerical aperture of the relay lens system. By varying the aperture size, the system can dynamically control the amount of spherical aberration introduced and adjust the pixel spread function characteristics, enabling optimization of both contrast and illumination distribution for different operating conditions
2Ease of operation
If spherical aberration is introduced to change pixel shape from square to Gaussian, then illumination control is improved, but the optical system complexity increases
Solution Approach 1:
The patent applies local quality by introducing spherical aberration specifically at certain regions of the optical system while maintaining other regions as aberration-free. The aperture stop is positioned to control which lens zones contribute to the aberration, creating a localized effect that shapes the pixel spread function without requiring complete redesign of the entire optical path
Solution Approach 2:
The patent uses the aperture stop as an intermediary element to control the spherical aberration introduction. By adjusting the aperture stop position and size, the system mediates between the lens elements to achieve the desired Gaussian-like pixel distribution without direct mechanical adjustment of the lenses themselves, simplifying the control mechanism
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 enhances the high dynamic range and contrast by spreading light effectively over the second light modulator, improving image predictability and reducing distortions, leading to better illumination control and higher contrast ratios.
Implementation Method 1
the relay light system of present implementations introduces a spherical aberration into the light
Implementation Method 2
A relay lens system there between relays light reflected from the first light modulator to the second light modulator
Data Source
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AI summary
Relay-lens (100) for a high dynamic-range projector comprising a light input (121), a light output (123), lenses (125) to relay light from the input (121) to the output (123) and an aperture stop (127), the combination of the lenses (125) with the provided numerical aperture introducing spherical aberration so that a square input-pixel (from SLM 103-1) having a step function be output (on SLM 103-2) by the relay-lens (100) as a Gaussian function having an upper boundary (UB(r)) and a lower boundary (LB(r)) with UB(r) = 1.1 exp(-(r/N)2), LB(r) = 0.45 (1 + cos(π r/N)) for r < N and LB(r) = 0 for r ≧ N, where r is the distance from the centre of the input-pixel and N is the dimension of an input dither-pattern.