Micro-relief Optical Element for Broadband Light Absorption
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Solution Overview
Problem
Conventional optical elements fail to provide sufficient light absorption in the infrared region and can cause contamination due to degassing issues, especially in optical apparatuses using vacuum ultraviolet light, which complicates their design and operation.
Innovation Solution
An optical element with a micro-relief structure on a substrate, such as silicon, coated with a metal layer film is developed, which offers high light absorption across the ultraviolet to infrared wavelength range, preventing contamination and allowing for compact arrangement in optical apparatuses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional black-coated plate or cone shape elements are used to absorb unwanted light, then light absorption property is improved in visible and ultraviolet region, but light absorption property deteriorates in infrared region due to reduction of absorption coefficient of silicon
Solution Approach 1:
The invention transitions from a flat two-dimensional surface to a three-dimensional micro-relief structure with numerous fine protrusions. This dimensional change increases the effective surface area and creates multiple reflection paths, enabling the structure to trap and absorb infrared light that would otherwise pass through or reflect off a flat surface, thereby resolving the wavelength-dependent absorption limitation.
Solution Approach 2:
The invention combines silicon substrate with a micro-relief structure and applies a black coating to create a composite light-absorbing element. The silicon provides structural support and baseline absorption, while the micro-relief structure enhances infrared absorption through geometric light trapping, and the black coating amplifies absorption across all wavelengths. This composite approach overcomes the limitation of silicon's reduced absorption coefficient in the infrared region.
2Loss of energy
If black coating is applied to reduce reflectance and prevent stray light, then light absorption property is improved, but contamination due to degassing issues occurs in vacuum ultraviolet light applications
Solution Approach 1:
The invention extracts the black coating material that causes degassing contamination and replaces it with an alternative light-absorbing mechanism. The micro-relief structure itself provides the light-trapping function, eliminating or reducing the need for problematic black coatings in vacuum ultraviolet applications, thereby removing the source of contamination while maintaining the desired light absorption performance.
Solution Approach 2:
The micro-relief structure acts as an intermediary between the incident light and the substrate, providing light absorption through geometric trapping rather than relying on black coating materials. This intermediary structure achieves the same functional goal (reducing reflectance and stray light) without introducing the harmful degassing contamination associated with conventional black coatings in vacuum environments.
3Measurement precision
If optical elements with light absorption properties are arranged to prevent stray light, then noise component is reduced, but device complexity increases
Solution Approach 1:
The micro-relief structure with black coating serves multiple functions simultaneously: it absorbs unwanted light to reduce stray light and noise, maintains structural integrity, and can be integrated directly into existing optical components like lenses and mirrors. This multi-functionality eliminates the need for separate light-absorbing elements, thereby reducing device complexity while maintaining noise reduction performance.
Solution Approach 2:
The invention merges the light-absorbing function with the existing optical element structure by forming the micro-relief structure directly on the optical component surface and applying black coating. This integration combines the optical functionality with the light absorption function in a single component, reducing the number of separate elements needed and simplifying the overall device design while effectively preventing stray light and noise.
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 optical element achieves low transmittance and reflectance across a wide wavelength range, effectively absorbing unwanted light components and preventing contamination, thus enhancing the performance and accuracy of optical apparatuses by reducing stray light and chromatic aberration.
Implementation Method 1
An optical element provided recently has a micro-relief structure (micro-relief structure) constituted of numerous micro-protrusions (fine protrusions) formed on a surface of a silicon layer formed on a substrate such as a silica substrate... reflectance is reduced by the above-described micro-relief structure, thereby reducing reflection noise
Implementation Method 2
The optical element achieves low transmittance and reflectance across a wide wavelength range, effectively absorbing unwanted light components... an optical element at least a partial section of which has a light absorption property
Data Source
AI summary
An optical element that includes a substrate having two surfaces, each of the surfaces having a micro-relief structure that includes numerous fine protrusions, and a film that includes one or more layers including a metal layer and that is formed on one of the micro-relief structures.