Spatial Light Modulator Zero-Order Noise Suppression
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Solution Overview
Problem
Phase-reproducing devices like pixellated spatial light modulators suffer from zero-order light issues, which act as noise and are not effectively managed in existing technologies, affecting image projection efficiency.
Innovation Solution
Modifying data applied to the spatial light modulator to create a replay field beyond the region where zero-order light converges, using additional diffractive means or shaping the SLM substrate to redirect zero-order light away from the imaging plane, and employing a light block to prevent its reach to the imaging plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If light passes through a spatial light modulator to create a replay field, then image projection efficiency is improved, but zero-order light noise is generated and converges to the imaging plane
Solution Approach 1:
The patent extracts and removes the zero-order light component from the optical path by positioning a light block at the Fourier plane where zero-order light converges. This separates the harmful zero-order light from the useful diffracted light that forms the image, allowing efficient image projection without noise contamination.
Solution Approach 2:
The patent introduces a light block as an intermediary element at the Fourier plane to intercept and block zero-order light before it reaches the imaging plane. This mediator selectively removes the harmful component while allowing the image-forming diffracted light to pass through to the replay field.
2Measurement precision
If the replay field is formed at the focal plane of a Fourier lens, then image reproduction is achieved, but zero-order light also converges to the same location creating noise
Solution Approach 1:
The patent extracts zero-order light from the convergence point at the Fourier lens focal plane by placing a light block at this location. This removes the harmful interference before it can contaminate the image reproduction process, allowing accurate replay field formation without noise.
Solution Approach 2:
The patent uses the predictable convergence behavior of zero-order light at the Fourier plane as a benefit by placing the light block precisely at this convergence point. The harmful zero-order light is reliably directed to a specific location where it can be efficiently blocked, converting its predictable harmful behavior into a controllable situation.
3Object-generated harmful factors
If a light block is placed at the Fourier plane to block zero-order light, then noise is reduced, but the optical path is obstructed
Solution Approach 1:
The patent applies local quality by placing the light block only at the specific location where zero-order light converges (the Fourier plane), rather than obstructing the entire optical path. This localized intervention blocks only the harmful zero-order light while leaving the useful diffracted light paths unaffected, minimizing impact on overall optical system functionality.
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
Effectively blocks zero-order light noise, improving image projection efficiency by ensuring that the replay field is formed beyond the zero-order light convergence point, enhancing the clarity and quality of projected images.
Implementation Method 1
a replay field representing the target image... to create a replay field representing the target image... imaging by diffraction
Implementation Method 2
applying the output beam to a Fourier lens to reproduce a two-dimensional image substantially corresponding to the target image in a replay field via the Fourier lens
Implementation Method 3
Light from the beam is reflected at the SLM 20 and the exit beam 16 passes into a Fourier lens
Data Source
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Figure 2
AI summary
A method of forming an image comprising providing a device for imparting respective phase-shifts to different regions of an incid¬ ent wavefront, wherein the phase shifts give rise to an image in a replay field, and causing zero-order light to be focused into a re¬ gion between the replay field and the device.