Blind-Spot Optical Member With Rough Prism Light Shielding
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Solution Overview
Problem
Blind spot assistance devices suffer from stray light that reduces visibility in blind spot areas due to reflections and transmissions through semi-transmissive mirrors and prisms, leading to reduced visibility for vehicle occupants.
Innovation Solution
An optical member with a light guide and prisms featuring a light shielding surface with a rough surface that scatters and absorbs stray light, reducing its reflection and transmission, thereby improving visibility in blind spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a semi-transmissive mirror and prisms are used in a blind spot assistance device, then light from blind areas can be reflected to the viewer, but stray light is generated that reduces visibility
Solution Approach 1:
The patent applies local quality by creating a rough surface specifically on the light shielding surface of the prism, while other surfaces maintain different properties. This localized roughness treatment targets only the area where stray light control is needed, allowing the rest of the optical system to maintain its light-guiding functionality. The rough surface with larger surface roughness selectively scatters stray light without affecting the primary light path from the blind spot area.
Solution Approach 2:
The patent converts the harmful effect of light reflection off the light shielding surface into a beneficial scattering effect. By intentionally creating a rough surface on the light shielding surface, the previously harmful reflected stray light is transformed into scattered light that diffuses in multiple directions, preventing it from reaching the viewer and thus converting a harmful reflection into a useful light-trapping mechanism.
2Illumination intensity
If a light shielding surface is added to block stray light, then visibility improves, but device complexity increases
Solution Approach 1:
Rather than adding a separate light shielding component, the patent modifies only a specific surface of the existing prism. The light shielding function is integrated into the prism structure itself through localized rough surface treatment on one surface, eliminating the need for additional parts while achieving stray light control.
Solution Approach 2:
The patent merges the light shielding function with the existing prism structure by making one surface of the prism serve dual purposes: maintaining its geometric function for light guidance while simultaneously acting as a light shielding surface through roughness treatment. This integration eliminates separate components and simplifies the overall device structure.
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 member effectively reduces stray light reaching the viewer, enhancing visibility in blind spot areas by scattering and absorbing light, thus improving the recognition of scenes obscured by pillars or other obstructions.
Implementation Method 1
the light shielding surface has a rough surface, and a surface roughness of the rough surface is larger than a surface roughness of the exit surface... light from the incident surface and light reflected by the second reflecting surface are incident on the light shielding surface
Implementation Method 2
a first reflecting surface that reflects light from the incident surface
Implementation Method 3
a second reflecting surface that reflects light reflected by the first reflecting surface
Data Source
AI summary
An optical member includes a light guide having: an incident surface on which an external scene light is incident from a blind area; a first reflecting surface that reflects light from the incident surface; and a second reflecting surface that reflects light reflected by the first reflecting surface. The optical member further includes a prism having: an exit surface that emits light from the incident surface and light reflected by the second reflecting surface to outside; and a light shielding surface connected to the exit surface to intersect the exit surface. A light from the incident surface and a light reflected by the second reflecting surface are incident on the light shielding surface. The light shielding surface has a rough surface, and a surface roughness of the rough surface is larger than a surface roughness of the exit surface.