Light Flux Controlling Member Grid Pattern Illumination
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Solution Overview
Problem
Conventional surface light source apparatuses produce unevenness in illuminance due to light emitted from light emitting elements being incident on the back surface of a light flux controlling member, leading to non-uniform planar illumination.
Innovation Solution
A light emitting apparatus with a light flux controlling member featuring a grid pattern of convex or concave parts on its back surface, which scatters light incident from the light emitting elements, preventing unevenness in illuminance by controlling the light's trajectory and ensuring uniform illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light emitting elements are arranged on the back surface of a light flux controlling member, then the apparatus can provide planar illumination, but unevenness in illuminance occurs due to direct incident light
Solution Approach 1:
The back surface of the light flux controlling member is segmented into multiple regions: a light incident region with a light incident surface for receiving light from LEDs, and a light emission region with a light emission surface for emitting light toward the liquid crystal panel. This segmentation separates the light reception and emission functions, preventing direct incident light from causing illuminance unevenness while maintaining planar illumination capability.
Solution Approach 2:
Different regions of the light flux controlling member are given different optical properties. The light incident region is designed to receive and redirect light, while the light emission region is designed to emit light uniformly. This local differentiation of optical functions ensures that light is properly controlled and distributed uniformly across the illumination area.
2Device complexity
If the back surface of the light flux controlling member is used as the light incident surface, then the structure is simplified, but annular bright spots and illuminance unevenness are generated
Solution Approach 1:
The light flux controlling member is divided into distinct functional regions: a light incident region with its own incident surface for receiving light from LEDs, and a light emission region with its emission surface for providing uniform illumination. This segmentation prevents the structural simplification of using the back surface directly as the incident surface, while avoiding the illuminance uniformity problems that would result from such a design.
3Productivity
If light is allowed to incident directly on the back surface, then the light flux controlling member can concentrate and emit light efficiently, but unevenness in illuminance is produced
Solution Approach 1:
The light flux controlling member is segmented into a light incident region that efficiently receives and redirects light from LEDs, and a light emission region that ensures uniform light distribution. This segmentation maintains high light emission efficiency by proper light redirection while eliminating illuminance unevenness through the separated emission region design.
Solution Approach 2:
The light flux controlling member acts as an intermediary between the LED light sources and the liquid crystal panel. By introducing the light incident region as an intermediate structure, light is properly redirected and distributed before reaching the emission region, maintaining efficiency while ensuring uniform illuminance distribution.
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 uniform illuminance and high-quality illumination by scattering light incident on the back surface of the light flux controlling member, reducing the formation of annular bright parts and enhancing the overall lighting quality.
Implementation Method 1
A light emitting apparatus with a light flux controlling member featuring a grid pattern of convex or concave parts on its back surface, which scatters light incident from the light emitting elements
Implementation Method 2
controls the traveling direction of light when emitting light from the light flux controlling member
Data Source
AI summary
A light flux controlling member has: a light control/emission surface that controls a traveling direction of light; a concavity that allows a main beam to be incident inside; and a back surface that extends in a radial direction from an opening rim part of the concavity and that allows sub-beams to be incident inside. One of a grid convex part which arranges a plurality of strips of convex parts in a grid pattern and a grid concave part which arranges a plurality of strips of concave parts in a grid pattern is formed in the back surface of the light flux controlling member.