Holographic Display CGH Optimization for Zero-Phase Amplitude Modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing holographic display technologies face challenges in accurately representing predetermined amplitudes and phases using amplitude spatial light modulators, leading to inefficiencies and the need for additional optical systems to compensate for incomplete phase modulation.
Innovation Solution
A holographic display apparatus that generates a computer-generated hologram (CGH) by optimizing phase and amplitude values using a gradient descent method, ensuring the phase on the reference plane is zero, thereby simplifying the optical system and enhancing light efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an amplitude spatial light modulator is used to represent predetermined amplitude and phase, then the device complexity is reduced, but the manufacturing precision deteriorates due to inability to accurately represent both amplitude and phase
Solution Approach 1:
The patent changes the parameter representation by generating a CGH where the phase values are constrained to be substantially zero, transforming the problem from representing arbitrary phase values to representing only amplitude information encoded in the hologram pattern. This parameter transformation enables accurate representation using amplitude-only modulators.
Solution Approach 2:
The patent uses computational copying by generating a computer-generated hologram that encodes the desired 3D image information in the amplitude distribution pattern. The CGH algorithm computationally replicates the effect of phase modulation through iterative optimization, copying the functionality of phase-modulating devices using amplitude-only modulation.
2Manufacturing precision
If additional optical systems are added to compensate for incomplete phase modulation, then the manufacturing precision improves, but the device complexity increases
Solution Approach 1:
The patent extracts the phase modulation requirement from the optical system by generating a CGH with zero phase values, separating the phase control function into the computational domain. This extraction eliminates the need for additional optical phase-modulating components, as the phase information is handled entirely through algorithmic generation rather than optical hardware.
3Measurement precision
If a CGH with non-zero phase values is generated, then the measurement precision of phase representation improves, but the loss of energy increases due to incomplete modulation
Solution Approach 1:
The patent changes the phase parameter from arbitrary non-zero values to substantially zero values, optimizing the energy efficiency of the amplitude spatial light modulator. By constraining the phase to zero, the system achieves complete and accurate amplitude modulation without energy loss from incomplete phase control, while still maintaining the ability to represent 3D images through the amplitude distribution in the CGH.
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 allows for precise representation of 3D images without the need for additional optical systems, improving light efficiency and reducing bulkiness, while maintaining high-quality 3D image reproduction.
Implementation Method 1
a spatial light modulator configured to modulate light from the light source according to an image to be displayed on an object plane
Implementation Method 2
the processor is further configured to generate the CGH by propagating a complex function corresponding to a respective hologram image to be displayed on each of the plurality of object planes toward the reference plane of the spatial light modulator
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A holographic display apparatus includes: a light source; a spatial light modulator configured to modulate light from the light source according to an image to be displayed on an object plane; and a processor configured to generate a computer generated hologram (CGH) in which a phase value of hologram data to be displayed on a reference plane of the spatial light modulator is 0, the processor being configured to apply a light modulation signal based on the CGH to the spatial light modulator.