LiDAR Antireflection Film Coating for Measurement Accuracy
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Solution Overview
Problem
Conventional LiDAR sensor units suffer from reduced measurement accuracy due to reflection lights arising at the inner and outer surfaces of the translucent cover, which interfere with the light receiving element and lead to incorrect object positioning.
Innovation Solution
A distance measuring device with a translucent cover coated with an antireflection film formed from a specific liquid composition containing a resin component, unevenness forming particles with specific size ratios, and a diluent solvent, applied via spray coating to achieve a thickness of 2 μm to 40 μm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a translucent cover is used to protect the light emitting element and light receiving element, then the protection and structural integrity are improved, but reflection lights arise at the inner and outer surfaces causing measurement accuracy to deteriorate
Solution Approach 1:
The patent applies an antireflection film coating to the translucent cover, which converts the harmful reflection effect into a beneficial transmission effect. The coating layer is specifically designed to reduce reflectance at the inner and outer surfaces of the cover, allowing more light to pass through while minimizing spurious reflections that would interfere with distance measurement accuracy.
2Measurement precision
If the translucent cover is made with specific optical properties to reduce reflections, then measurement accuracy is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent modifies the optical parameters of the translucent cover by introducing an antireflection film coating with specific properties (thickness, refractive index, material composition). This coating is designed to operate at the wavelength of the detection light and provides reflection suppression through controlled optical parameter changes rather than fundamental design changes to the cover structure itself.
Solution Approach 2:
The translucent cover system becomes a composite structure combining the base cover material with an antireflection film coating layer. This composite approach allows the cover to maintain its protective function while the coating layer provides the optical enhancement needed to reduce reflections and improve measurement accuracy.
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 antireflection film effectively suppresses reflection lights, enhancing the accuracy of distance measurements by reducing the impact of internal and external reflections on the light receiving element.
Implementation Method 1
a reflection light toward the inner direction (inside the unit) arises at its inner surface and outer surface in some cases. When the reflection light enters a light receiving element
Implementation Method 2
the antireflection film is configured by a membrane having a thickness of 2 μm or more and 40 μm or less formed from a liquid composition by spray coating
Data Source
AI summary
A distance measuring device 1 capable of achieving high measurement accuracy is provided. The distance measuring device 1 comprises a LiDAR sensor unit 7 in a storage chamber 5 partitioned inside an exterior member 2. The LiDAR sensor unit 7 comprises a light emitting element 71 for emitting a detection light L1 for measuring a distance to an object, a light receiving element 73 for outputting a light-receiving signal S1 in accordance with an amount of an incident light, and a translucent cover 3 for covering the light emitting element 71 and light receiving element 73. Antireflection films 9a and 9b are provided at least on one main surface side of the translucent cover 3. The antireflection films 9a and 9b are configured by a membrane having a thickness of 2 μm or more and 40 μm or less formed from a liquid composition having a specific composition by spray coating.