Optical Member With Prism Light Guide for Ghost Image Suppression
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Solution Overview
Problem
Conventional optical members using light-transmitting materials for blind spot auxiliary devices suffer from ghost images due to light entering from surfaces other than the incident surface, which disrupts the visibility of the blind spot area.
Innovation Solution
A light guide body with protruding incident prism portions and a light-shielding back cover that covers the entire reflective surface, preventing light from entering the reflective surface and using total reflection to guide light without mirrors, thereby suppressing ghost images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light-transmitting light guide body is used to guide external scenery light, then the blind spot area can be viewed, but ghost images occur due to light entering from surfaces other than the incident surface
Solution Approach 1:
The patent extracts and blocks the harmful light paths by introducing a back cover that specifically covers the reflective surface and prevents light from entering from unintended surfaces. This separates the useful light guidance function from the harmful light entry paths, allowing the former to continue while the latter is eliminated.
Solution Approach 2:
The back cover acts as an intermediary element between the light guide body and the external environment. It mediates by selectively blocking harmful light paths while allowing the light guide body to continue its primary function of guiding external scenery light to the exit surface.
2Object-generated harmful factors
If the back cover covers the entire reflective surface across a gap, then ghost images are suppressed, but the structural complexity increases
Solution Approach 1:
The patent segments the optical member into distinct functional components: the light guide body with its specific surface features (incident surface, reflective surface, exit surface) and the separate back cover. This segmentation allows each component to be optimized independently and simplifies the overall design by dividing the light-blocking function into a dedicated element rather than requiring complex modifications to the light guide body itself.
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 solution effectively suppresses ghost images and enhances visibility of the blind spot area by ensuring total reflection and blocking unintended light entry, improving the user's perception of the external scenery.
Implementation Method 1
an incident surface that allows an external scenery light to enter the inside of the light guide body
Implementation Method 2
a reflective surface adjacent to the incident part... allows a part of incident light entering from an incident surface to reflect therein
Implementation Method 3
The back cover covers at least an entire area of the reflective surface of the light guide body across a gap
Data Source
AI summary
An optical member includes a light-transmitting light guide body and a light-shielding back cover. The light guide body has an incident part including a plurality of protruding incident prism portions, a reflective surface adjacent to the incident part, and an exit surface facing the incident part and the reflective surface. Each of the plurality of incident prism portions has an incident surface that allows an external scenery light to enter the inside of the light guide body and an adjacent surface adjacent to the incident surface. The back cover covers at least an entire area of the reflective surface of the light guide body across a gap, and abuts against the adjacent surface of a rear prism portion that is one of the plurality of incident prism portions adjacent to the reflective surface.