Telecentric Interference Filter Optical Probe for Angle-Independent Color Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional measuring optical systems for color luminance meters and colorimeters face limitations with optical absorption filters, including limited design flexibility, low transmittance, and severe aged deterioration, as well as high error sensitivity due to incident angle variations when using interference filters.
Innovation Solution
The system employs interference filters with a collecting lens group formed as a substantially bilateral telecentric system to adjust the transmittance characteristic, ensuring uniform light distribution and reducing the impact of incident angle deviations, allowing for stable and accurate measurement across various angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical absorption filters are used, then design flexibility is limited and transmittance is low, but stability against heat and light is poor
Solution Approach 1:
The patent changes the fundamental parameter of filter technology from optical absorption to optical interference. By using interference filters with multiple dielectric layers, the system achieves high stability against heat and light while maintaining high transmittance, directly resolving the contradiction between reliability and energy loss.
2Loss of energy
If interference filters are used, then design flexibility and transmittance are improved, but error sensitivity due to incident angle variations increases
Solution Approach 1:
The patent applies local quality by creating a telecentric optical system where the incident angle is controlled and uniformized at the specific location of the interference filter. The telecentric lens ensures that light rays arrive at the filter at consistent angles, locally optimizing the filter's performance and eliminating angle-dependent measurement errors.
Solution Approach 2:
The telecentric optical system creates an equipotential condition for incident angles across the interference filter surface. By ensuring that all light rays strike the filter at the same angle (typically normal incidence), the system eliminates variations in transmittance that would otherwise occur due to angle differences, making the measurement immune to positional variations.
3Ease of manufacture
If conventional optical absorption filters are used, then manufacturing is simpler, but design freedom is limited
Solution Approach 1:
The patent employs composite materials by stacking multiple dielectric layers with different refractive indices to create interference filters. This composite structure enables precise control over transmission characteristics and allows for complex spectral shapes that cannot be achieved with simple absorption filters, greatly expanding design freedom while remaining manufacturable through established vacuum deposition techniques.
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 the use of interference filters with enhanced design flexibility, high stability, and reduced light intensity loss, while minimizing errors induced by incident angle variations, thereby improving the accuracy and reliability of color luminance and chromaticity measurements.
Implementation Method 1
This interference filter is configured by laminating several tens of dielectric layers or oxide layers on a glass substrate through vacuum deposition, spattering or other process, and operable to select a transmission/reflection wavelength by the action of optical interference.
Implementation Method 2
it is introduced into the interference filter through a respective one of two or more collecting lens groups each formed as a substantially bilateral telecentric system
Data Source
AI summary
In a measuring probe (40) according to the present invention, measuring light is split into a two or more through a split optical system (12), and, when each split light is received by a light-receiving sensor (13B, 13B, 15B) through an interference filter (13A, 14A, 15A) serving as a color filter, the split light is introduced into the interference filter (13A, 14A, 15A) through a collecting lens group (123C, 14C, 15C) formed as a substantially bilateral telecentric system. The interference filter (13A, 14A, 15A) is formed to obtain a transmittance characteristic corresponding to a measurement parameter, depending on a condition of an intensity distribution with respect to incidents angles of light incident on the interference filter (13A, 14A, 15A). Thus, the measuring probe (40) according to the present invention can reduce an influence of a deviation in the transmittance characteristic due to incident angles, even using the interference filter (13A, 14A, 15A).