Optical Gap Measurement for Diffractive Elements
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Solution Overview
Problem
Existing test systems for diffractive optical elements are inadequate in accurately determining the size of the gap between substrates, which affects the quality and intensity of the projected optical patterns in 3D optical imaging systems.
Innovation Solution
An optical test system and method that involves a light source, a holding stage, a sensor, and a controller to measure intensity signals from diffractive optical elements at multiple positions, using reference data from optical element models with varying gap sizes to determine the gap size between substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing test systems are used for inspection of diffractive optical elements, then general inspection capabilities are provided, but accurate determination of gap size between substrates is not achieved
Solution Approach 1:
The patent replaces mechanical measurement methods with an optical measurement system. A light source emits light through the diffractive optical element at multiple positions, and a sensor detects the transmitted light intensity. The gap size is determined by analyzing the intensity signals and comparing them against reference data, eliminating the need for complex mechanical measurement equipment.
Solution Approach 2:
The patent introduces an intermediary measurement approach using light intensity signals as a mediator to indirectly determine the gap size. Instead of directly measuring the physical gap, the system uses the optical intensity transmission through the element at multiple positions as an intermediary parameter that correlates with the gap dimension, enabling precise measurement through optical means.
2Manufacturing precision
If gap size is not accurately determined, then manufacturing and testing can be simplified, but quality and intensity of projected optical patterns deteriorate
Solution Approach 1:
The patent replaces complex mechanical testing procedures with a simplified optical measurement system. By using light transmission through the diffractive optical element and analyzing intensity signals at multiple positions, the system achieves accurate gap size determination without requiring complex mechanical measurement equipment or procedures.
Solution Approach 2:
The patent creates a simplified optical model for measurement where light intensity signals serve as a copy or representation of the physical gap dimension. By measuring the optical intensity transmission pattern and comparing it against reference data, the system obtains accurate gap size information without directly measuring the physical structure.
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
Accurately determines the gap size between substrates of diffractive optical elements, ensuring high-quality optical patterns with controlled intensity, without the need for electrical tests, thereby reducing operational complexity and costs.
Implementation Method 1
a diffractive optical element is used in the optical pattern projection system for creating the desired projection pattern
Implementation Method 2
a light receptor such as a 3D camera for receiving light reflected from an object and forming a 3D image of the object from the reflected light
Data Source
AI summary
An optical test method is provided. The optical test method includes emitting light through a gap between two substrates of a tested optical element disposed on a holder to generate a plurality of light beams. The optical test method further includes driving the holder with the tested optical element to move to N positions. The optical test method also includes receiving one of the light beams from the tested optical element in the N positions to generate N first intensity signals. In addition, the optical test method includes determining the size of the gap of the tested optical element according to the N first intensity signals and reference data.