Light Guide With Variable Pitch And Depth Prisms
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Solution Overview
Problem
Existing light guides face challenges in achieving a uniform light emitting surface while maintaining a thin thickness, as deeper prisms are required for efficient light reflection, but this limits the thickness of the light guide, making it difficult to design thin-film light guides with large areas without unevenness in pitch and depth.
Innovation Solution
A light guide design featuring a first region with variable pitch and a second region with variable depth, where the depth of V-shaped prisms is adjusted to maintain a maximum depth of 10µm or less, allowing for a thin-sheet light guide with a large area to achieve a uniform light emitting surface without visual unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the depth of prisms is increased to improve light reflection efficiency, then the light guide can guide light more effectively, but the thickness of the light guide must be increased, making it impossible to achieve thin-film designs
Solution Approach 1:
The patent applies local quality by varying the prism depth according to position. Prisms near the light source have greater depth for efficient light extraction, while prisms farther away have reduced depth. This spatial variation in prism depth allows the light guide to maintain thin overall thickness while still achieving effective light reflection and distribution across the entire surface.
Solution Approach 2:
The patent changes the parameter of prism depth as a function of position along the light guide. By making the prism depth a variable parameter rather than a constant, the design optimizes light reflection efficiency at different locations while constraining the maximum thickness of the light guide structure.
2Ease of manufacture
If the pitch between prisms is increased to reduce manufacturing complexity, then the number of prisms is reduced, but visual unevenness appears on the light emitting surface
Solution Approach 1:
The patent applies local quality by implementing different pitch values in different regions of the light guide. The first region has a first pitch value optimized for uniform light distribution, while the second region has a second pitch value that may differ to accommodate edge effects or specific optical requirements. This regional differentiation maintains visual uniformity while managing manufacturing complexity.
3Area of stationary object
If the light guide area is increased to achieve larger display sizes, then more light coverage is provided, but the required prism depth becomes impractically large for thin-film applications
Solution Approach 1:
The patent resolves this contradiction by making prism depth a spatially varying parameter. Light sources positioned at different locations have associated prisms with depths optimized for their specific positions. This allows large-area light guides to be designed with thin overall thickness, as no single location requires excessively deep prisms.
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
This design secures the necessary thickness for light guidance and enables the fabrication of large area patterns, such as 50 inches by 65 inches, with a thickness of 0.3mm, while preventing visual unevenness and ensuring efficient light reflection, thus overcoming the limitations of previous designs.
Implementation Method 1
a bottom surface having plural grooves on which the light is reflected
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3~5
AI summary
Provided a light guide (11) including side surfaces on which light is incident, a reflection prism surface having plural prisms (12) on which light is reflected, and a light emitting surface from which the light is emitted, in which the reflection prism surface includes a first region (PA) in which a pitch of the prisms (12) varies and a second region (TA) in which a depth of the prisms (12) varies. In the light guide (11), the first region is arranged in the side surface on which the light is incident, and a second region (TA) is arranged adjacent to the first region and in an inward side of the light guide (11).