Spectroscopic Apparatus Temperature-Compensated Capacitance Control
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Solution Overview
Problem
Spectroscopic apparatuses with interference filters face challenges in maintaining precise wavelength control due to temperature changes, which affect the gap between reflection films, leading to shifts in the wavelength of light transmitted and inaccuracies in electrostatic capacity measurements.
Innovation Solution
A spectroscopic apparatus with a temperature detection unit and module control unit that corrects the target value of the capacitance detection signal based on temperature characteristics, adjusting the voltage applied to the gap changing unit to maintain precise wavelength dispersion, using a correction coefficient derived from actual measurement values at various temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If feedback control is performed based on electrostatic capacity detection to calibrate the gap dimension to a target value, then the dimension control is simplified, but the wavelength precision deteriorates due to temperature-induced detection errors
Solution Approach 1:
A temperature detection unit is introduced as an intermediary to detect the temperature of the spectroscopic module. This temperature information is then used to correct the target value of the detection signal, allowing the system to account for temperature-induced detection errors while maintaining simple feedback control operation.
Solution Approach 2:
The target value of the detection signal is dynamically adjusted based on temperature measurements. By changing the target parameter according to temperature conditions, the system compensates for temperature-induced errors in the capacity detection circuit, thereby maintaining wavelength precision without complicating the control mechanism.
2Device complexity
If the gap dimension is controlled based on average capacity values, then the control process is simplified, but the actual wavelength transmission precision deteriorates due to temperature variations in the detection circuit
Solution Approach 1:
The system uses temperature detection feedback to dynamically adjust the target value of the detection signal. This feedback mechanism allows the simple average-based control process to compensate for temperature variations, maintaining both low complexity and high precision in wavelength transmission.
3Measurement precision
If individual table data is created for each spectroscopic module to compensate for temperature characteristics, then the wavelength precision is improved, but the manufacturing cost and complexity increase
Solution Approach 1:
Instead of creating individual table data for each module, the system dynamically adjusts the target value parameter based on real-time temperature measurements. This approach achieves the same precision improvement as individual calibration tables without the complexity of storing and managing separate data sets for each module.
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 high-precision light spectral-dispersion with the target wavelength, reducing manufacturing costs by eliminating the need for individual table data for each spectroscopic module and improving precision by using a reliable temperature coefficient based on actual measurements.
Implementation Method 1
an electrostatic capacity between the pair of reflection films is measured with a capacity detection circuit
Implementation Method 2
a gap changing unit which changes a dimension of a gap between the pair of reflection films by application of a voltage
Implementation Method 3
a temperature detection unit that detects a temperature of the spectroscopic module
Implementation Method 4
an interference filter that has a pair of reflection films... a wavelength of a light that passes through the interference filter
Data Source
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AI summary
A spectroscopic apparatus includes: a spectroscopic module; a temperature detection unit that detects a temperature of the spectroscopic module; and a module control unit that controls the spectroscopic module, in which the spectroscopic module includes an interference filter that has a pair of reflection films, and a gap changing unit which changes a dimension of a gap between the pair of reflection films by application of a voltage, and a capacity detection circuit that outputs a detection signal in accordance with an electrostatic capacity between the pair of reflection films, and in which the module control unit corrects a target value of the detection signal that is output from the capacity detection circuit, based on a temperature characteristic of the spectroscopic module and a detection temperature that is detected by the temperature detection unit, and controls the voltage that is to be applied to the gap changing unit, in such a manner that the detection signal that is output from the capacity detection circuit is the corrected target value.