Wide Field-of-View Projector Using Spatial Light Modulator
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Solution Overview
Problem
Conventional video projectors using wedge-shaped light guides face issues such as visible bands in projected images due to uneven reflection, inability to focus on multiple locations simultaneously, and limited ability to fan-out images 90 degrees.
Innovation Solution
A wide field-of-view projector is implemented, featuring a spatial light modulator that injects light rays into an input wedge to increase the fan-out angle, allowing for a holographic image projection with improved focus and coverage, using a combination of spatially-varying modulation and an input wedge that amplifies the fan-out angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional video projectors use wedge-shaped light guides to project images, then the projection function is achieved, but visible bands appear in the projected image due to uneven reflection
Solution Approach 1:
The patent applies local quality by using a spatial light modulator to independently control the phase or amplitude of light at different spatial locations. This allows differential modulation of light rays entering different regions of the wedge-shaped light guide, compensating for the uneven reflection that causes visible bands. Each local region of the light guide receives tailored optical input to achieve uniform overall illumination.
2Adaptability or versatility
If conventional projectors use standard optical paths, then the projection structure is simple, but the ability to focus on multiple locations simultaneously is lost
Solution Approach 1:
The patent implements dynamics by using a spatial light modulator that can dynamically and independently adjust the optical properties (phase or amplitude) for each spatial location. This dynamic control enables the system to focus light at multiple different locations simultaneously by programmatically configuring the modulation pattern, providing flexible multi-point focusing without requiring multiple fixed optical components.
3Ease of operation
If wedge-shaped light guides are used in conventional projectors, then the projection function is achieved, but the ability to fan-out an image 90 degrees is limited
Solution Approach 1:
The patent applies parameter changes by utilizing the wedge-shaped light guide's geometry to transform the propagation angle of light rays. The wedge angle is specifically designed to convert a small input fan-out angle from the spatial light modulator into a large output fan-out angle (up to 90 degrees). This geometric parameter transformation achieves wide angular distribution without requiring complex mechanical or optical scanning mechanisms.
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
The solution enables a wide field-of-view projector to produce a holographic image with increased fan-out angle, addressing the limitations of conventional projectors by ensuring simultaneous focus on multiple locations and eliminating visible bands, thereby enhancing image projection quality and versatility.
Implementation Method 1
a spatial light modulator configured to inject light rays into an input wedge
Implementation Method 2
Rays of light injected into a thick end of a wedge-shaped light guide, which tapers from a thick end to a thin end, will reflect back and forth at progressively steeper angles until exiting the wedge when a 'critical angle' is reached
Data Source
AI summary
This document describes various techniques for implementing a wide field-of-view projector. A wide field-of-view projector may include a spatial light modulator configured to inject light rays into an input wedge. The input wedge acts to output the light rays with an increased fan-out angle. In an embodiment, the spatial light modulator is controlled to inject light rays into the input wedge effective to project an image from the surface of an output wedge that is positioned proximate, and receives light rays with an increased fan-out angle from, the input wedge.