Ultrathin Micro-Spectrometer With Back-Reflection Grating Layout
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Solution Overview
Problem
Concave grating-based spectrometers suffer from low spectral resolution and non-uniform sensitivity due to the Rowland profile, leading to deteriorated spectral performance and increased volume, making size reduction challenging.
Innovation Solution
A back-reflection grating structure is employed, integrating a convex lens with a reflective diffraction grating and planar reflectors on a substrate, minimizing optical path length and enhancing spectral resolution and sensitivity through multi-reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If a concave grating structure is used to minimize optical path length, then the volume of the spectrometer is reduced, but the spectral resolution deteriorates and sensitivity becomes non-uniform due to the Rowland profile
Solution Approach 1:
The patent inverts the conventional grating configuration by using a planar diffraction grating instead of a concave grating. This inversion allows the use of a linear detector array while maintaining uniform spectral resolution across the detection range, eliminating the Rowland profile problem that causes non-uniform sensitivity in concave grating systems.
Solution Approach 2:
The patent segments the optical system into distinct functional components: a planar diffraction grating for wavelength separation, a linear detector array for signal detection, and optimized optical paths for collimation and focusing. This segmentation allows each component to be optimized independently, achieving compact size without compromising spectral resolution.
2Measurement precision
If optical components are precisely arranged in a Czerny-Turner or Fastie-Ebert structure, then spectral resolution can be maintained, but the volume of the spectrometer inevitably increases
Solution Approach 1:
The patent merges the functions of collimation and diffraction into a more compact configuration by using a planar grating with optimized optical paths. This combining of functions reduces the number of separate optical components and their spacing requirements, achieving miniaturization while maintaining spectral resolution.
Solution Approach 2:
The patent transitions from the conventional planar configuration of Czerny-Turner or Fastie-Ebert structures to a three-dimensional optimized optical path design. This dimensional optimization allows for shorter optical paths and more compact arrangement of components, reducing overall spectrometer volume while maintaining measurement precision.
3Volume of stationary object
If micro-machining is used to reduce the size of optical components, then the spectrometer volume decreases, but manufacturing complexity and cost increase
Solution Approach 1:
The patent adopts planar diffraction gratings that can be manufactured using standard semiconductor fabrication techniques rather than requiring complex precision machining of concave surfaces. This approach uses inexpensive, easily manufacturable components that can be produced at scale, reducing both manufacturing complexity and cost while enabling miniaturization.
Solution Approach 2:
The patent changes the geometric parameters of the optical components from complex concave surfaces to simple planar structures with precisely controlled periodic patterns. This parameter change enables the use of standard photolithography and etching processes for manufacturing, dramatically simplifying production while maintaining the required optical performance for compact spectrometer design.
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 ultrathin micro-spectrometer achieves improved spectral resolution and uniform sensitivity across the visible light range, enabling compact design and cost-effective mass production.
Implementation Method 1
a lens portion including a convex lens
Implementation Method 2
a back-reflection grating layer which is formed on a rear surface of the convex lens and on the same surface of which a reflective diffraction grating and a first planar reflector are arranged
Implementation Method 3
a back-reflection grating structure is employed, integrating a convex lens with a reflective diffraction grating and planar reflectors on a substrate, minimizing optical path length and enhancing spectral resolution and sensitivity through multi-reflection
Implementation Method 4
a complementary metal-oxide-semiconductor (CMOS) sensor on which light reflected by the lens portion is focused
Data Source
AI summary
The disclosure relates to an ultrathin micro-spectrometer and a method of manufacturing the same, and more particularly, relates to an ultrathin micro-spectrometer including: a lens portion including: a convex lens; and a back-reflection grating layer which is formed on a rear surface of the convex lens and on the same surface of which a reflective diffraction grating and a first planar reflector are arranged; a substrate layer which is disposed to be spaced apart from the lens portion and on which a light incidence microslit is formed; a second planar reflector which is formed on the substrate layer; and a complementary metal-oxide-semiconductor (CMOS) sensor on which light reflected by the lens portion is focused, and a method of manufacturing the same.