Confocal Measuring Device Diffractive Lens Chromatic Aberration
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Solution Overview
Problem
Conventional confocal measuring devices face challenges in enlarging the measurement target range without compromising the measurement accuracy or increasing the device size, as increasing the focal distance of the objective lens affects the measurement center distance and numerical aperture, leading to reduced performance.
Innovation Solution
The implementation of a confocal measuring device configuration that includes a first diffractive lens causing chromatic aberration, a second diffractive lens to further increase chromatic aberration, and a divergence optical part to collimate light, allowing for a larger measurement range without changing the measurement center distance or numerical aperture of the objective lens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the focal distance of the objective lens is increased to enlarge the measurement target range, then the measurement target range is expanded, but the measurement center distance changes and the numerical aperture decreases, leading to reduced measurement accuracy
Solution Approach 1:
The patent segments the chromatic aberration generation function into two separate diffractive lenses (first and second diffractive lenses) positioned before the objective lens. This segmentation allows each lens to contribute partially to the chromatic aberration, enabling a broader measurement range while the objective lens maintains its original focal distance and numerical aperture, thus preserving measurement accuracy.
Solution Approach 2:
The patent introduces diffractive lenses as intermediary elements between the light source and the objective lens. These intermediary diffractive lenses generate the necessary chromatic aberration to expand the measurement range, while the objective lens itself remains unchanged, maintaining its optimal performance characteristics for accurate measurement.
2Area of stationary object
If multiple axial dispersion focusing elements are used to broaden the measurement target range, then the measurement range is expanded, but the distances among the elements increase, leading to increased device size
Solution Approach 1:
The patent merges the chromatic aberration generation function into a compact configuration using two diffractive lenses positioned in close proximity before the objective lens. This combined approach achieves the same effect as multiple dispersed elements but in a much more compact form factor, avoiding the need for large distances between elements.
Solution Approach 2:
Instead of expanding the device in one dimension by spacing out multiple elements, the patent achieves the measurement range expansion by manipulating the optical properties (chromatic aberration) in a different dimensional approach, allowing compact integration of the measurement range expansion function.
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 a broader measurement range while maintaining the accuracy and performance of the measurement center distance, allowing for compact device design and efficient chromatic aberration generation.
Implementation Method 1
a first diffractive lens that causes chromatic aberration in the light emitted from the light source
Implementation Method 2
a second diffractive lens that increases chromatic aberration of light passing through the first diffractive lens
Implementation Method 3
an objective lens that condenses light passing through the second diffractive lens into a measurement target range along an optical axis such that the condensed light has chromatic aberration along the optical axis
Implementation Method 4
a measurement part that measures strength of light of a wavelength focused on a measurement target object among light condensed by the objective lens
Data Source
AI summary
A confocal measuring device capable of enlarging a measurement range using a compact device configuration is provided. A confocal measuring device (1A) is configured to include: a diffractive lens (11) that causes chromatic aberration in light emitted from a white LED light source (21); a diffractive lens (13b) that increases chromatic aberration of light passing through the diffractive lens (11); and an objective lens (12) that condenses light into a measurement target range such that the condensed light has chromatic aberration along an optical axis.