Light Guide Sideward Visibility Elevations
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Solution Overview
Problem
Conventional light guides make it difficult to determine if a light source is on or off when the viewing angle is small, which is a challenge in applications like kitchen lighting.
Innovation Solution
A light guide with a transparent element having a first surface for receiving light and a second surface with elevations that direct a portion of the light sideways, providing total internal reflection and refraction to make the light source visible even at small viewing angles, with the sideward-directed light being at most 10% of the total light exiting the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional light guides are used, then light distribution is modified, but visibility of light source status at small viewing angles deteriorates
Solution Approach 1:
The patent introduces a new spatial dimension by adding elevations to the second surface of the light guide, which redirect light into sideward directions. This dimensional modification creates additional light paths that are visible at small viewing angles, resolving the contradiction between maintaining light distribution control and improving visibility.
Solution Approach 2:
The patent applies local quality modification by introducing elevations only at specific locations on the second surface of the light guide. These localized structures selectively redirect light in sideward directions while leaving the rest of the surface unchanged, thus improving visibility without compromising the overall light distribution pattern.
2Difficulty of detecting and measuring
If elevations are added to direct light sideward, then visibility of light source status improves, but light loss increases
Solution Approach 1:
The patent applies partial action by designing elevations that redirect only a portion of the light (at most 10%) into sideward directions. This partial redirection is sufficient to improve visibility of the light source status while minimizing light loss, as the majority of light continues to exit through the second surface in its original direction.
3Illumination intensity
If prism ridges are used for collimating light, then light distribution is controlled, but visibility at small viewing angles deteriorates
Solution Approach 1:
The patent merges the functions of light collimation and sideward light redirection by combining prism ridges on the first surface with elevations on the second surface. This combination allows the light guide to simultaneously control light distribution through collimation while also providing sideward light paths for visibility at small viewing angles.
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 allows for easier identification of the light source's status at small viewing angles, enhancing visibility and usability in domestic lighting applications.
Implementation Method 1
Each elevation is shaped to provide total internal reflection for a light beam belonging to the first part of the light at a first point of the surface of the elevation
Implementation Method 2
refract the reflected light beam at a second point of the surface of the elevation so as to direct the light beam sideward
Data Source
AI summary
A light guide (201) including a transparent element is presented. The transparent element includes a first surface (203) for acting as a light-ingress surface and a second surface (204) for acting as a light-egress surface. The second surface includes elevations (205) for directing a part of the light into directions sideward with respect to a direction in which another and greater part of the light exits the transparent element through the second surface. Each elevation is shaped to provide total internal reflection for a light beam on a first point of the surface of the elevation and refract the reflected light beam on a second point of the surface of the elevation so as to direct the light beam sideward. The sideward directed light enables an observer, who sees the light guide from a small viewing angle, to easily see whether the light is on or off.