Rotating Filter Carousel for Compact Spectral Camera

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Solution Overview

Problem

Existing spectral cameras with flexible filters are not compact, preventing the use of interchangeable lenses and efficient multispectral imaging due to complex constructions and lack of focusing arrangements.

Innovation Solution

A spectral camera with a rotatable filter carousel containing multiple spectral filters around a cylindrical support, allowing quick scanning of different wavelengths and integration of interchangeable lenses and electronics, enabling compact and efficient multispectral imaging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If filters are mounted in a rotating cylinder as disclosed in WO9404893, then multiple spectral filters can be accessed, but the construction becomes non-compact and prevents interchangeable lenses

Engineering Contradiction:
Improvemultiple spectral filters accessVSAvoidcamera compactness
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent transitions from a linear/planar filter arrangement to a cylindrical three-dimensional configuration. Filters are arranged radially around a central optical axis, allowing the light beam to pass through the center of the cylinder and interact with filters at different angular positions. This dimensional change enables a compact form factor while maintaining access to multiple filters.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The cylindrical filter carousel is designed to work with interchangeable lenses mounted on a C-mount interface. The same cylindrical structure accommodates both the filter array and the lens mounting mechanism, allowing the system to perform multiple functions (spectral filtering and variable focal length imaging) within a single integrated unit.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If mirrors are used within the filter cylinder to reflect light onto filters, then light can be directed through filters, but the construction becomes complex and non-compact

Engineering Contradiction:
Improvelight direction through filtersVSAvoidcylinder internal construction
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent removes the mirrors from the cylindrical filter assembly, extracting this function from the system. Instead of using mirrors to redirect light onto filters, the design allows light to pass directly through the center of the cylinder, eliminating the need for internal reflective surfaces and simplifying the overall construction.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Rather than reflecting light onto filters using mirrors, the patent inverts the approach by having filters arranged around a central light path that passes through the cylinder. This reversal of the light interaction geometry eliminates the need for mirrors while achieving the same spectral filtering function.

Inventive Principle:
Principle #13The other way round (Inversion)

3Productivity

If the filter cylinder is rotated to change filters, then different wavelengths can be scanned, but the mechanism prevents straightforward interchangeable lens use

Engineering Contradiction:
Improvewavelength scanning capabilityVSAvoidinterchangeable lenses
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent segments the optical system into distinct functional modules: the interchangeable lens mounted on a C-mount interface and the cylindrical filter carousel. This segmentation allows each component to be optimized independently - the lens can be changed without affecting the filter mechanism, and the filter carousel can rotate independently to select different wavelengths.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system incorporates dynamic elements including the rotatable filter carousel for wavelength selection and the interchangeable lens mounting mechanism for focal length adjustment. These dynamic components are designed to work independently, allowing the lens to be swapped without interfering with the rotational filter selection mechanism.

Inventive Principle:
Principle #15Dynamics

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 solution enables fast, accurate, and automated multispectral imaging with a wide wavelength range, high spatial resolution, and easy filter customization, while maintaining a compact and user-friendly design.

Implementation Method 1

a plurality of spectral filters arranged around a cylindrical surface

Methodology Applied
Scientific EffectSpectral filtering: Filter (optical)

Implementation Method 2

a camera lens

Methodology Applied
Scientific EffectFocusing: Focusing

Data Source

PatentEP3475673B1Spectral camera having interchangeable filters
Publication Date: 2024.02.28 XPECTRALTEK LDA
  • EP3475673B1 patent drawingFigure 1~2
  • EP3475673B1 patent drawingFigure 3~4
  • EP3475673B1 patent drawingFigure 5~6

AI summary

The present disclosure relates to a spectral camera, in particular to a spectral camera having multiple filters mounted interchangeably within the optical path of the camera. It is disclosed a spectral camera having a plurality of spectral filters arranged around a cylindrical support, thus providing a filter carrousel, wherein the image sensor is placed within said carrousel.