Side-edge Light Guide with Perpendicular Prism Sheet for Privacy and Brightness
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Solution Overview
Problem
Prior art side-edge type surface light emitting apparatuses improve privacy effect but decrease luminous intensity due to the use of light absorbing sheets, which absorb leaked light, resulting in suboptimal performance in both privacy and illumination.
Innovation Solution
Incorporating a second prism sheet with prisms perpendicular to the light incident surface of the light guide plate, which redirects and absorbs leaked light, enhancing privacy effect while increasing luminous intensity by allowing more light to be emitted from the primary prism sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light absorbing sheet is used to improve privacy effect, then light leakage at side angles is reduced, but luminous intensity at the center decreases
Solution Approach 1:
The invention divides the light management function into two separate components: an upper prism sheet for extracting and emitting light forward, and a lower prism sheet for redirecting backward-leaking light back into the light guide plate. This segmentation allows each component to specialize in one function, improving overall system performance rather than using a single component that compromises both functions.
Solution Approach 2:
The lower prism sheet acts as an intermediary between the light guide plate and the light absorbing sheet. Instead of allowing light to be directly absorbed (wasting energy), the lower prism sheet intercepts leaking light and redirects it back into the light guide plate, where it can be extracted by the upper prism sheet. This intermediary component converts a harmful effect (light leakage) into a useful resource (additional extractable light).
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 effectively improves the privacy effect by reducing light emission at specific angles while maintaining or increasing luminous intensity at the central angle, thus achieving a balance between privacy and illumination performance.
Implementation Method 1
a first prism sheet having multiple first prisms opposing the first light emitting surface of the light guide plate
Implementation Method 2
a light absorbing sheet opposing the light distribution controlling surface of the light guide plate
Implementation Method 3
a second prism sheet having a flat surface opposing the light distribution controlling surface of the light guide plate and multiple second prisms opposing the light absorbing sheet
Data Source
AI summary
A side-edge type surface light emitting apparatus includes: a light guide plate having a first light emitting surface, a light distribution controlling surface opposing the first light emitting surface and a light incident surface; a light source disposed on the light incident surface; a first prism sheet having multiple first prisms opposing the first light emitting surface and a second light emitting surface opposing the multiple first prisms; a light absorbing sheet opposing the light distribution controlling surface; and a second prism sheet having a flat surface opposing the light distribution controlling surface and multiple second prisms opposing the light absorbing sheet, the multiple second prisms being perpendicular to the light incident surface of the light guide plate.