Variable Wavelength Interference Filter Telecentric Guidance
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Solution Overview
Problem
Existing optical devices with variable wavelength interference filters face resolution degradation due to deflection issues in the movable section, leading to decreased measurement accuracy, especially when the filter size increases to improve resolution with image sensors.
Innovation Solution
The optical device incorporates a telecentric optical system that guides incident light perpendicularly to the variable wavelength interference filter, defining an effective measurement area where the gap dimension variation is minimized, and a magnifying lens system to enhance detection accuracy without enlarging the filter size, along with circularly polarizing plates to prevent ghosting and improve detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the size of the variable wavelength interference filter is increased to improve resolution with a larger image sensor, then the resolution and measurement accuracy are improved, but the deflection amount of the movable section increases causing resolution degradation
Solution Approach 1:
The patent changes the physical parameters of the movable section by making its thickness dimension larger than that of the diaphragm. This parameter change increases the stiffness of the movable section, thereby reducing its deflection amount even when the filter size is increased, while still allowing the filter to achieve high resolution with a larger image sensor.
2Measurement precision
If the size of the variable wavelength interference filter is increased to improve resolution, then the measurement accuracy is improved, but the deflection amount of the movable section increases degrading resolution
Solution Approach 1:
The patent modifies the dimensional parameters of the movable section, specifically making the thickness dimension larger than the diaphragm dimension. This parameter modification reduces the deflection amount of the movable section, thereby maintaining uniform gap dimensions across the filter surface even when the filter size is increased, ensuring both high measurement accuracy and gap uniformity.
3Reliability
If the thickness dimension of the movable section is made larger than the diaphragm, then the deflection amount is reduced, but the device complexity increases
Solution Approach 1:
The patent employs a parameter change approach by adjusting the thickness dimension of the movable section to be larger than the diaphragm dimension. This single parameter modification achieves deflection control without requiring additional complex structural elements, mechanisms, or components, thereby reducing device complexity while improving deflection control.
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 highly accurate spectroscopic measurements by maintaining resolution within an allowable range and preventing ghosting, allowing for larger detection sections without increasing filter size, thus improving measurement accuracy and reducing operational complexities.
Implementation Method 1
an interference filter having a pair of reflecting films opposed to each other, and for transmitting or reflecting only the light with a predetermined wavelength, which is reinforced due to multiple interference by the pair of reflecting films
Implementation Method 2
the telecentric optical system guides a principal ray of the incident light perpendicularly to one of a plane of the first reflecting film and a plane of the second reflecting film
Implementation Method 3
along with circularly polarizing plates to prevent ghosting and improve detection accuracy
Data Source
AI summary
An optical device includes a telecentric optical system, a variable wavelength interference filter, and a detection section, the variable wavelength interference filter includes a first reflecting film, a second reflecting film provided to a movable section, and an electrostatic actuator adapted to displace the movable section, an effective measurement area capable of transmitting a light with a wavelength, which is within a predetermined allowable range centered on a measurement center wavelength when an amount of the displacement of the movable section takes a maximum displacement value, is set in the first reflecting film and the second reflecting film, and the telecentric optical system guides the incident light to the variable wavelength interference filter so that a principal ray of the incident light is parallel thereto and perpendicular to the first reflecting film, and at the same time, collects the incident light in the effective measurement area.