Dielectric Multilayer Film Optical Scanning Element for High-Speed MEMS Mirrors
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Solution Overview
Problem
Existing optical scanning elements face challenges in maintaining accurate and high-speed scanning due to temperature increases caused by high-output light sources, leading to distortion and changes in resonance frequency, particularly in light deflectors with heat releasing structures and MEMS mirrors with dielectric multilayer films.
Innovation Solution
An optical scanning element featuring a dielectric multilayer film that reflects most incident light while transmitting a small portion, with a substrate designed for minimal light absorption, and a movable unit with a through-hole to direct transmitted light to an absorption member, preventing temperature increases and maintaining resonance frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a high-output light source is used to improve scanning brightness, then illumination intensity is improved, but temperature of the mirror increases causing distortion and resonance frequency change
Solution Approach 1:
The patent segments the light interaction path by introducing a beam splitter that divides incident light into reflected and transmitted components. The dielectric multilayer film on the mirror reflects only the necessary portion while transmitting the rest to an absorption member, preventing excessive heat accumulation on the mirror while maintaining sufficient scanning brightness.
Solution Approach 2:
The patent introduces an absorption member as an intermediary element to handle excess light energy. The beam splitter directs transmitted light from the dielectric multilayer film to this absorption member, which converts excess light energy into heat that can be dissipated separately, preventing the mirror from overheating while maintaining system brightness.
2Temperature
If a solid heat transfer body is added to release heat, then temperature control is improved, but device complexity and size increase
Solution Approach 1:
The dielectric multilayer film serves multiple functions simultaneously: it acts as the reflective coating for the mirror, a beam splitter that divides light into reflected and transmitted portions, and a protective layer. This multi-functionality eliminates the need for separate heat dissipation structures, reducing device complexity while maintaining effective temperature control.
Solution Approach 2:
The patent employs passive heat dissipation through the substrate and absorption member without requiring active cooling systems or complex thermal management components. The structure naturally directs excess light energy to the absorption member and dissipates heat through the substrate, achieving temperature control through the inherent design rather than additional active systems.
3Illumination intensity
If a dielectric multilayer film is used to reflect light, then reflectance is improved, but light absorption by the film or substrate causes temperature increase
Solution Approach 1:
The patent optimizes the optical parameters of the dielectric multilayer film to achieve high reflectance for the scanning wavelength while maintaining high transmission for the beam splitter function. By carefully controlling film thickness, material composition, and layer structure, the system achieves over 98% reflectance when needed while allowing excess light to pass through to the absorption member, minimizing heat generation in the film and substrate.
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 accurate and high-speed scanning by minimizing temperature increases in the mirror unit and maintaining resonance frequency, even with high-output light sources, while reducing device cost and size.
Implementation Method 1
a dielectric multilayer film that reflects a part of incident light while transmitting the remainder of the light
Implementation Method 2
a dielectric multilayer film that reflects a part of incident light while transmitting the remainder of the light
Implementation Method 3
a through-hole to direct transmitted light to an absorption member, preventing temperature increases
Data Source
AI summary
Provided is an optical scanning element that includes mirror unit 1, and movable unit 2 including mounting unit 7 on which mirror unit is mounted and which is configured to be rotatable. Mirror unit 1 includes: a dielectric multilayer film that reflects a part of incident light while transmitting the remainder of the light; and a first substrate on one surface of which the dielectric multilayer film is formed, and which transmits the remainder of the light passed through the dielectric multilayer film. Mounting unit 7 includes a through-hole at a portion facing the dielectric multilayer film.