Light Guide Shielding for Clear Blind Spot Optical Viewing
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Solution Overview
Problem
Existing optical devices suffer from issues where outside light is reflected by flat portions of the light guide and superimposed on the external scene light, degrading visibility, especially in blind spot areas.
Innovation Solution
The optical device incorporates a light guide with flat and prism portions, and a light shielding portion to block outside light from entering and being reflected towards the viewer, maintaining total reflection conditions without semi-transmissive mirrors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a semi-transmissive flat mirror is used to display external scene light, then the external scene image can be displayed, but outside light is reflected by flat portions and superimposed on the external scene light, degrading visibility
Solution Approach 1:
The patent removes the semi-transmissive flat mirror from the optical path and instead uses a light guide with flat portions that directly guide external scene light to the viewer's eye. This extraction of the mirror eliminates the problem of outside light being reflected by the mirror and superimposed on the external scene light, thereby degrading visibility.
Solution Approach 2:
The patent introduces a light guide as an intermediary component between the external scene and the viewer's eye. The light guide with its flat portions guides the external scene light while preventing outside light from entering the eye, thus mediating the interaction between external light and the viewer without the harmful reflection effects of a semi-transmissive mirror.
2Illumination intensity
If a semi-transmissive flat mirror is used, then additional optical components are required, but this increases device complexity
Solution Approach 1:
The patent extracts and removes the semi-transmissive flat mirror from the optical system, simplifying the device structure. By eliminating this component, the patent reduces the number of optical elements required while still achieving the function of displaying external scene light through the light guide's flat portions.
Solution Approach 2:
The light guide serves multiple functions: it guides external scene light to the viewer, prevents outside light from entering the eye, and eliminates the need for separate mirror components. This multi-functionality reduces overall device complexity while maintaining the required optical performance.
3Device complexity
If the light guide structure is simplified without semi-transmissive mirrors, then device complexity is reduced, but outside light may enter the light guide and degrade image clarity
Solution Approach 1:
The patent applies different surface properties to different parts of the light guide: flat portions for guiding external scene light and prism portions for preventing outside light entry. This local differentiation of surface quality allows the simplified structure to effectively block harmful outside light while maintaining optical functionality.
Solution Approach 2:
The patent converts the potential harmful effect of outside light entry into a beneficial filtering mechanism. The prism portions are specifically designed to allow external scene light to pass through while blocking outside light from entering the light guide, thus converting what could be a harmful intrusion into a selective filtering advantage.
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 device effectively prevents outside light from superimposing on the external scene image, enhancing visibility by clearly displaying blind spot areas without using additional mirrors, thus improving image clarity.
Implementation Method 1
The plurality of flat portions of the first surface totally reflects the external scene light traveling inside the light guide toward the second surface
Implementation Method 2
The second surface totally reflects the external scene light reflected by the plurality of flat portions toward the first surface
Implementation Method 3
The light shielding portion is provided on a surface of the light guide or at a position away from the light guide so as to block an outside light from entering the light guide
Implementation Method 4
Each of the prism portions has an exit surface for outward emitting a part of the external scene light incident from the incident surface and a part of the external scene light reflected by the second surface
Data Source
AI summary
An optical device includes a light guide and a light shielding portion. The light guide has: an incident surface on which an external scene light coming from a blind area is incident; a first surface including flat portions and prism portions; and a second surface opposite to the flat portions. The light shielding portion is provided on a surface of the light guide or at a position away from the light guide so as to block an outside light entering the light guide. The light shielding portion has a first light shielding portion for blocking light incident on an inclined surface and a second light shielding portion for blocking light incident on the flat portion in a predetermined direction.