Hologram Coupling into Waveguide via Segmented Input Port
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Solution Overview
Problem
Existing holographic projection systems face challenges in efficiently coupling holographic wavefronts into waveguides, particularly in multiplexing multiple holograms without significant light loss.
Innovation Solution
The system employs a waveguide pupil expander with an input port that includes multiple input areas for receiving holographic wavefronts from different channels. By appropriately positioning these input areas and using internal reflections within the waveguide, the system achieves efficient coupling and multiplexing of holographic wavefronts without the need for additional optical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple holograms are multiplexed in the waveguide using conventional methods, then multiple channels can be combined, but significant light loss occurs
Solution Approach 1:
The patent utilizes the waveguide thickness dimension to position input areas at different depths along the propagation direction. By arranging first and second input areas at different positions along the thickness of the waveguide, multiple holographic wavefronts can be coupled into the waveguide without requiring lateral separation, thereby maintaining optical efficiency while achieving multiplexing capability.
Solution Approach 2:
The input port of the waveguide is segmented into multiple distinct input areas (first input area, second input area) positioned at different locations along the thickness direction. Each input area is dedicated to receiving holographic wavefronts from different channels, allowing independent coupling optimization for each channel while maintaining overall system efficiency.
2Productivity
If multiple input areas are positioned at different locations along the thickness direction, then coupling efficiency is improved, but device complexity increases
Solution Approach 1:
The waveguide structure serves multiple functions simultaneously: it acts as both the optical propagation medium and the multiplexing element. The different input areas positioned along the thickness direction all couple into the same waveguide core, which then handles all channels through its inherent waveguiding properties, eliminating the need for separate coupling structures for each channel.
Solution Approach 2:
Multiple input areas are nested along the thickness dimension of the waveguide, with each input area positioned at a different depth. This nested arrangement allows multiple channels to be introduced at different levels within the same waveguide structure, maximizing space utilization while maintaining simple external geometry.
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 enables optically efficient coupling of holographic wavefronts into the waveguide, allowing for the multiplexing of multiple channels within the waveguide while minimizing light loss, and facilitates the creation of full-color holographic projections using a single display device.
Implementation Method 1
By appropriately positioning the first and second input area, the first and second holographic wavefronts can be combined, or superimposed on one another, within the waveguide after one or more internal reflections therein
Data Source
AI summary
A holographic projection system includes a display arrangement. The display arrangement includes a display area arranged to display a first hologram of a first picture and to spatially modulate light incident thereon in accordance with the first hologram to form a holographic wavefront. The system further includes an optical system arranged to receive the holographic wavefront and form a relayed image of the first hologram. The system further includes a waveguide that includes an input port arranged to receive the holographic wavefront and a pair of surfaces arranged to waveguide the holographic wavefront therebetween. A plane of the display area is angled such that the relayed image of the first hologram is formed at a first plane, the first plane being parallel with a plane of the input port.