Variable Light Attenuator with Optical-Path Control for Compact Photometry
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Solution Overview
Problem
Existing photometric devices face challenges with large size and reduced accuracy due to the use of rotating ND filters, which increase the device's size and affect measurement precision.
Innovation Solution
A photometric device with a variable light attenuator comprising multiple light attenuation filters and a driving device, where each filter has a different optical path length and can be independently inserted or retracted along the optical axis, using interference multilayer films and transparent substrates to stabilize light intensity within the photodetector's dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If rotating ND filters are used to control light intensity, then light attenuation can be achieved, but the device size increases
Solution Approach 1:
The patent extracts the rotating plate and motor components from the light attenuating means, retaining only the necessary ND filters arranged in a fixed linear configuration. This extraction of unnecessary mechanical components achieves compact device size while maintaining light attenuation functionality.
Solution Approach 2:
The patent replaces the mechanical rotating plate system with a linear scanning mechanism that moves filters along the optical axis. This substitution reduces mechanical complexity and device size while achieving the same light attenuation effect through a simpler linear motion system.
2Measurement precision
If multiple ND filters are arranged on a rotating plate, then light intensity control is achieved, but measurement accuracy decreases due to interference
Solution Approach 1:
The patent transitions from a planar arrangement of filters on a rotating plate to a three-dimensional linear arrangement along the optical axis. This dimensional change allows filters to be positioned at different distances from the light source, enabling control of optical path lengths to minimize interference effects and improve measurement accuracy.
3Length of moving object
If a linear scanning mechanism is used to move filters along the optical axis, then device size is reduced, but mechanical complexity increases
Solution Approach 1:
The patent designs the linear scanning mechanism to serve multiple functions: it positions filters along the optical axis, controls their insertion and retraction, and enables precise control of optical path lengths. This multi-functionality reduces the need for separate components, thereby reducing overall device size while managing mechanical complexity.
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 device achieves a more compact size and higher measurement accuracy by stabilizing light intensity and reducing variations in measurement results caused by interference between multiple reflected light beams.
Implementation Method 1
Each of the plurality of light attenuation filters includes an interference multilayer film and a transparent substrate that supports the interference multilayer film
Data Source
AI summary
The photometric device includes a variable light attenuator. The variable light attenuator includes a plurality of light attenuation filters and a driving device. Each of the plurality of light attenuation filters includes an interference multilayer film and a transparent substrate. A combination of any two of the plurality of light attenuation filters is set as a first light attenuation filter and a second light attenuation filter. A first optical path length of the first transparent substrate of the first light attenuation filter is different from a second optical path length of the second transparent substrate of the second light attenuation filter.