Faceted Light Guide Collimator for Homogeneous Display Backlighting
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Solution Overview
Problem
Existing light guide designs for display devices in motor vehicles face inefficiencies in light deflection, leading to unwanted stray light and loss of efficiency when compact designs are required, especially with curved deflection surfaces that increase the aperture for stray light.
Innovation Solution
A light guide with a collimator that converts light into collimated light and incorporates a stepped structure with angled legs and flanks to selectively deflect light, preventing stray light and ensuring homogeneous backlighting without the need for baffles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a curved deflection surface is used to increase deflection efficiency, then deflection efficiency is improved, but the length of the curved section increases, thus widening the aperture for unwanted stray light
Solution Approach 1:
The deflection surface is segmented into multiple planar facets arranged at different angles rather than using a continuous curved surface. Each facet deflects light in a specific direction, collectively achieving the desired light distribution without requiring a long curved section, thus maintaining high deflection efficiency while minimizing the aperture for stray light.
Solution Approach 2:
The invention transitions from a two-dimensional curved surface to a three-dimensional faceted structure with multiple planar surfaces oriented at different angles. This dimensional transformation allows light to be deflected through multiple discrete angular paths, achieving efficient light redirection in a more compact configuration that reduces the stray light aperture.
2Loss of energy
If the length of the curved section is increased to improve deflection efficiency, then deflection efficiency is improved, but the compactness of the design is reduced
Solution Approach 1:
The deflection function is segmented across multiple planar facets rather than distributed along a long curved section. Each facet performs a portion of the deflection task, allowing the overall deflection to be achieved in a more compact arrangement that reduces the length of the light guide while maintaining high deflection efficiency.
Solution Approach 2:
The invention replaces the curved surface with a faceted planar structure. Instead of using curvature to achieve gradual light redirection, multiple flat surfaces at different angles provide discrete deflection steps, achieving the same optical effect in a more compact, angular configuration that reduces the required length.
3Device complexity
If a planar deflection surface is used, then the design is simpler, but deflection efficiency is reduced, resulting in loss of 50% or more
Solution Approach 1:
The deflection surface is divided into multiple planar facets with different orientations, each contributing to the overall deflection efficiency. While more complex than a single planar surface, the faceted structure maintains relative simplicity compared to curved surfaces while achieving significantly higher deflection efficiency by distributing the deflection function across multiple angled surfaces.
Solution Approach 2:
The invention adds angular dimensionality to the deflection surface by incorporating multiple planar facets at different angles rather than using a single planar or curved surface. This multi-angular approach significantly improves deflection efficiency while keeping the structure relatively simple and manufacturable.
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 achieves efficient, homogeneous backlighting of display panels with minimal light loss, allowing for compact designs and virtually borderless displays by utilizing light effectively across the light guide.
Implementation Method 1
the input area has a collimator (421) that converts the light (301) into collimated light (310)
Implementation Method 2
the deflection area (470) has a light-deflection surface (471) for deflecting the collimated light (310) into the light-guiding area (460), wherein the light deflection surface (471) is arranged at an angle of 45° to the orientation of the collimated light (310) and to the axis (480) of the light guide area (460)
Implementation Method 3
The light propagates through the light guide by total internal reflection and is then extracted again by microstructures on the light guide
Data Source
Figure 1a~1c
Figure 2
Figure 3
AI summary
The present invention relates to an optical fiber (400) for a display device (100) with a display panel (200). The optical fiber (400) has an input area (420) for coupling light (301) from a light source (300). The input area (420) has a collimator (421) which converts the light (301) into collimated light (310), wherein the optical fiber (400) has a light guide area (460) for guiding the collimated light (310) along an axis (480). The light-guiding area (460) has a top surface (461) which is designed parallel to the axis (480) and a bottom surface (462) which is inclined relative to the axis (480) and has a structure (463) for deflecting the collimated light (310) incident on the bottom surface (462) as deflected light (311) towards the top surface (461).The structure (463) is designed to provide homogeneous, planar backlighting of the top surface (461), wherein the light guide (400) has a deflection area (470) with a light deflection surface (471) for deflecting the collimated light (310) into the light guide area (460). The light deflection surface (461) is arranged at an angle (α1) of 45° to the orientation of the collimated light (310) and to the axis (480) of the light guide area (460). The collimator (421) has a stepped structure (430).