Holographic Projector Contrast Measurement Without Detector Repositioning
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Solution Overview
Problem
Conventional methods for measuring conjugate contrast in holographic replay fields are inaccurate due to rotational misalignments and optical distortions, leading to indeterminate conjugate locations and inability to calculate conjugate contrast effectively.
Innovation Solution
A method is developed to measure conjugate contrast by displaying a first feature at a specific position and its conjugate at a calculated location using static detectors, allowing for precise intensity measurements without requiring detectors to be physically moved, and calculating conjugate contrast using the intensities of the feature and its conjugate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods are used to measure conjugate contrast, then measurement can be performed, but measurement precision deteriorates due to rotational misalignments and optical distortions
Solution Approach 1:
Instead of moving detectors to track the conjugate image location, the patent inverts the approach by calculating where to place a test feature so that its conjugate appears at a predetermined detector location. This reverses the cause-effect relationship: rather than following the conjugate, we position the feature to bring the conjugate to the detector, thereby eliminating alignment errors and achieving reliable measurements.
2Measurement precision
If detectors are physically moved to track conjugate image location, then measurement can be performed, but device complexity and ease of operation worsen due to required physical repositioning
Solution Approach 1:
The patent replaces the mechanical system of physically moving detectors with a computational approach. By calculating the appropriate position for the test feature based on known optical parameters and distortion characteristics, the system achieves the same measurement goal without mechanical repositioning, thereby simplifying operation and reducing complexity.
3Ease of operation
If static detectors are used, then ease of operation improves, but measurement precision deteriorates due to inability to track conjugate image location
Solution Approach 1:
The patent applies preliminary action by pre-calculating the optimal position for the test feature before measurement. Using knowledge of the optical system's distortion characteristics and the desired detector location, the system determines in advance where to place the feature so that its conjugate will appear exactly at the detector, enabling static detectors to achieve high measurement precision.
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
Enables accurate measurement of conjugate contrast in holographic replay fields, allowing for improved calibration and optimization of holographic projectors, reducing the need for physical detector repositioning and simplifying alignment processes.
Implementation Method 1
The hologram may be reconstructed by illumination with suitable light to form a two-dimensional or three-dimensional holographic reconstruction, or replay image, representative of the original object
Implementation Method 2
The holographic projector may additionally comprise a light source, such as a laser, arranged to illuminate the spatial light modulator
Implementation Method 3
The holographic projector may additionally comprise one or more optical components such as one or more lenses or mirrors
Data Source
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AI summary
There is provided a method for determining an intensity ratio of a holographic replay field. The method comprises forming a holographic replay field at a plane comprising a housing, wherein the holographic replay field comprises an image area and a non-image area. The method further comprises displaying a first feature at a first position of the holographic replay field. The method further comprises measuring an intensity IA of the first feature using a first light detector, wherein the first light detector is disposed on the housing. The method further comprises displaying a second feature at a second position of the holographic replay field, wherein the second feature is substantially identical to the first feature and forms a conjugate at the position of a second light detector. The second light detector is disposed on the housing. The method further comprises measuring an intensity IB' of the conjugate image of the second feature using the second light detector. The method further comprises calculating a ratio of the intensities IA, IB' of the first feature and the conjugate image of the second feature.