Prism Sheet Apex Angle and Diffusion Haze for Thin Lighting Glare Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thin lighting devices with narrow light distribution angles struggle to emit non-glare light while maintaining a compact size, as they often result in glare and make foreign substances on the surface visible, and existing solutions either fail to provide sufficient collimation or compromise light distribution properties.
Innovation Solution
A lighting device configuration featuring a light guide plate, light emitting diodes (LEDs) on a side surface, a prism sheet on the upper surface, and a reflective sheet on the lower surface, with a diffusion sheet between the light guide plate and the prism sheet, where the prism sheet's apex angle and the diffusion sheet's haze value are optimized to control light direction and reduce glare.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a prism sheet is used to control light direction in a thin lighting device, then the light distribution angle is narrowed, but glare is generated and foreign substances become easily noticeable
Solution Approach 1:
A diffusion sheet is introduced as an intermediary component between the light guide plate and the prism sheet. This diffusion sheet has a haze value of 30-65% and serves to diffuse the light before it reaches the prism sheet, reducing glare and making foreign substances less noticeable while still allowing the prism sheet to control the light distribution angle effectively
Solution Approach 2:
The apex angle of the prisms on the prism sheet is optimized to be within 55-66 degrees. This specific parameter range allows the prism sheet to effectively control the light distribution angle while working synergistically with the diffusion sheet to minimize glare and foreign substance visibility
2Length of moving object
If a parabolic mirror is used to form parallel light, then the light distribution angle is narrowed, but the light source needs sufficient depth and cannot be reduced in size
Solution Approach 1:
The patent replaces the traditional parabolic mirror mechanical system with an optical system consisting of a light guide plate, diffusion sheet, and prism sheet. This substitution eliminates the need for deep parabolic mirror structure while achieving the same light collimation and directional control functions through optical refraction and diffusion mechanisms
Solution Approach 2:
Instead of using a three-dimensional parabolic mirror structure that requires significant depth, the patent employs a planar arrangement of optical components (light guide plate, diffusion sheet, and prism sheet) that achieve light control in a different dimensional approach, resulting in a thin-profile lighting device
3Length of moving object
If LEDs are disposed on the side surface of the light guide plate with a prism sheet on the main surface, then the device is made thin, but the light is totally reflected from the prism causing glare
Solution Approach 1:
The diffusion sheet acts as an intermediary between the light guide plate and the prism sheet, diffusing the light that would otherwise be totally reflected from the prism. This diffusion process reduces the intensity of direct reflections and minimizes glare while maintaining the thin device structure
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 configuration achieves a narrow light distribution angle with non-glare emission, maintaining compactness and preventing foreign substances from appearing as defects, while ensuring effective collimation and uniform light distribution.
Implementation Method 1
a light guide plate, a plurality of light emitting diodes, a prism sheet, and a reflective sheet
Implementation Method 2
A diffusion sheet exists between the upper surface of the light guide plate and the prism sheet. A haze value of the diffusion sheet is between 30% and 65%
Implementation Method 3
a prism sheet disposed on a side toward an upper surface of the light guide plate... Prisms on the first prism array are extended in the first direction, and arrayed in a second direction perpendicular to the first direction
Implementation Method 4
The reflective sheet is disposed on a side toward a lower surface of the light guide plate
Data Source
AI summary
Disclosed is a lighting device including a light guide plate, a plurality of LEDs, a prism sheet disposed on a side toward the upper surface of the light guide plate, and a reflective sheet disposed on a side toward the lower surface of the light guide plate. The plurality of LEDs are arrayed on a side surface corresponding to a first side of the light guide plate in a first direction along the first side. The prism sheet includes a first prism array that is formed on a surface facing the light guide plate. The first prism array includes prisms that are extended in the first direction and arrayed in a second direction perpendicular to the first direction. The upper surface of the light guide plate and the prism sheet sandwich a diffusion sheet therebetween. The diffusion sheet has a haze value between 30% and 65% when measured in compliance with JIS K7361. The prisms on the first prism array have an apex angle between 55 degrees and 66 degrees.