Light Guide Surface Geometry for Uniform Elongated Display Luminance
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Solution Overview
Problem
Existing luminaire systems using a single light source struggle to uniformly diffuse light across an elongated display, resulting in varying luminance along the longitudinal direction, particularly on the sides relative to the optical axis.
Innovation Solution
A luminaire design featuring a light guide with a flat first surface and an inclined second surface, where the angle of the inclined surface increases on the peripheral side, allowing light to be reflected and diffused uniformly perpendicular to the optical axis, ensuring consistent luminance across the display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single light source is used to illuminate an elongated display plate, then the device complexity is reduced, but the luminance uniformity across the display plate deteriorates
Solution Approach 1:
The light guide plate employs varying thickness with different refractive indices at different locations to control light propagation. The thickness increases from the light source side toward the emission side, creating local optical property variations that redirect light laterally to achieve uniform luminance distribution across the elongated display plate.
Solution Approach 2:
The invention changes the physical parameter of the light guide plate by varying its thickness dimension. This parameter change creates corresponding changes in the refractive index distribution, enabling the plate to function as both a structural support and an optical element that uniformly diffuses light from a single source across the entire display area.
2Area of stationary object
If the display plate is made elongated in the horizontal direction, then the area to be illuminated is increased, but the luminance on the side parts relative to the optical axis is reduced
Solution Approach 1:
The invention introduces a vertical dimension (thickness variation) to the otherwise two-dimensional light guide plate. By varying the thickness in the vertical direction, the plate creates three-dimensional optical pathways that redirect light from the central optical axis toward the peripheral side regions, thereby illuminating the entire elongated area uniformly without requiring additional light sources.
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 luminaire effectively diffuses light from a single source uniformly in the direction perpendicular to the optical axis, maintaining consistent luminance along the longitudinal direction of the elongated display.
Implementation Method 1
light which is incident from the first surface portion, then is reflected by the second surface portion, is further reflected by the first surface portion
Data Source
AI summary
A luminaire is provided with a light source, and a light guide which is positioned in front of the light source. The light guide includes a first surface portion formed on the light source side, and a second surface portion formed on a side opposite the first surface portion. The first surface portion is constituted by a flat surface, and the second surface portion is constituted by an inclined surface which intersects at an angle other than a right angle against the optical axis of the light source. An angle formed between the inclined surface and the optical axis on the side of the light source is smaller on a center side of the second surface portion positioned on the optical axis, and is larger on a peripheral side of the second surface portion.