Digital Holographic Imaging With Coherent Plane Wave Illumination
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Solution Overview
Problem
Existing digital holographic image-taking apparatuses face challenges in capturing interference patterns over a wide field of view while maintaining a compact and cost-effective design, particularly in ensuring sufficient space for object placement and achieving size reduction without compromising the quality of the interference pattern capture.
Innovation Solution
The apparatus employs a coherent illumination system with a semiconductor laser and an optical waveguide optical system that diffracts light into a plane waveform, allowing the light emission surface to be brought closer to the object while ensuring adequate space for object placement, and uses a pixel array with a cover glass or object holder to capture interference patterns without the need for lenses, thereby achieving a wide field of view and size reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional digital holographic image-taking apparatus uses a laser light source with object lens and eyepiece lens to capture interference patterns, then the interference pattern can be captured, but the apparatus becomes large in size and complex in structure
Solution Approach 1:
The patent extracts and removes the complex lens system (object lens and eyepiece lens) from the conventional digital holographic apparatus. By eliminating these optical components, the apparatus achieves a simplified structure while maintaining the capability to capture interference patterns through direct illumination and sensor detection
Solution Approach 2:
The patent segments the optical system into minimal essential components: a laser light source, a diffuser plate, and an image sensor. This segmentation removes unnecessary intermediate optical elements and creates a streamlined configuration that reduces device complexity while preserving measurement functionality
2Area of stationary object
If the light emission surface is positioned far from the object to ensure sufficient space for object placement, then object placement is adequate, but the apparatus size increases
Solution Approach 1:
The patent transitions from a conventional optical path arrangement to a configuration where the light emission surface is positioned in close proximity to the object plane. By using a diffuser plate to create diffuse illumination and directly capturing the interference pattern on the image sensor, the system eliminates the need for large longitudinal spacing between components, effectively utilizing the lateral dimension for object placement while minimizing the apparatus footprint
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 configuration enables the capture of interference patterns over a wide field of view with a compact and cost-effective setup, allowing for precise analysis of objects by ensuring the necessary space for object placement and maintaining the quality of interference pattern capture.
Implementation Method 1
an illumination portion having a light emission surface for emitting illumination light of a specific wavelength toward an object, the illumination light being in a coherent plane waveform
Implementation Method 2
the image sensor capturing an interference pattern generated based on the illumination light having acted on the object
Data Source
AI summary
A digital holographic image-taking apparatus includes an illumination portion having a light emission surface for emitting illumination light toward an object, the illumination light having a specific wavelength in a coherent plane waveform; and an image sensor having an pixel array including two-dimensionally arranged pixels, the image sensor capturing an interference pattern generated based on the illumination light having acted on the object, in which the following conditional expression is satisfied: 0.0000001<Z2/S<16, where S represents the area of the light emission surface, and Z represents the distance from the light emission surface to the pixel array.