Hologram Side Lobe Control for Compact Wearable HUDs
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Solution Overview
Problem
Wearable heads-up displays face challenges in minimizing bulk while providing high-quality images and maintaining external environment visibility, with existing designs being bulky and lacking aesthetic appeal due to large display components.
Innovation Solution
A method for producing holograms with controlled side lobes using a recording substrate with a master hologram and holographic recording material, replicating the master hologram with at least two reference beams to manage side lobe intensity, and incorporating these holograms into wearable heads-up displays to enhance optical performance and aesthetics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If large display components are used to provide high-quality images in wearable heads-up displays, then visual quality is improved, but device bulk and size increase
Solution Approach 1:
The patent uses a master hologram as a template to create multiple replicated holograms in the holographic recording medium. This copying approach allows high-quality optical patterns to be reproduced without requiring large physical display components, as the holographic information can be stored compactly in the recording medium.
Solution Approach 2:
The patent transitions from conventional two-dimensional display components to three-dimensional volumetric holographic storage. By recording holographic patterns throughout the volume of the recording medium rather than on a flat surface, the system achieves high visual quality in a compact form factor, effectively utilizing the third dimension to reduce overall device bulk.
2Manufacturing precision
If conventional hologram recording methods are used, then hologram efficiency is achieved, but side lobe intensity remains uncontrolled and degrades image quality
Solution Approach 1:
The patent applies preliminary anti-action by introducing phase-modulated reference beams before the hologram recording process. These pre-modulated beams create interference patterns that actively counteract and suppress the formation of strong side lobes during hologram recording, preventing the harmful effect rather than attempting to correct it afterward.
Solution Approach 2:
The patent changes the phase parameter of the reference beams used in hologram recording. By modulating the phase of reference beams and using multiple reference beams with different phase relationships, the system controls the interference pattern formation, thereby controlling side lobe intensity while maintaining hologram efficiency.
3Object-generated harmful factors
If multiple reference beams are used to control side lobes, then side lobe intensity is reduced, but recording process complexity increases
Solution Approach 1:
The patent segments the reference beam into multiple separate beams, each with controlled phase relationships. This segmentation allows independent control of each reference beam's contribution to the hologram recording, enabling precise side lobe suppression through phased interference while maintaining systematic control over the overall recording process.
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 approach results in more aesthetically pleasing and compact wearable heads-up displays with improved visual quality by minimizing side lobe intensity, reducing bulk, and maintaining unobstructed external environment visibility.
Implementation Method 1
the holographic medium will diffract laser light with the same angle and pattern as the second beam of laser light used to record the hologram
Implementation Method 2
A pattern of optical fringes may be generated by the interference of two beams of laser light
Data Source
AI summary
Systems, devices, and methods for side lobe control in holograms are described. The magnitude of the side lobes of a hologram depends on the distribution of refractive index modulation (Δn), therefore control of side lobe magnitude may be achieved by controlling the distribution of Δn. The distribution of Δn may be controlled by replicating a hologram from a master with two reference beams, where the wavelength and angle of each reference beam, the playback angle of the master hologram, and the thickness of the master hologram, the copy holographic recording medium (HRM), and the recording substrate are carefully chosen to achieve a pattern of meta-interference within the HRM that matches the desired distribution of Δn.