Conical Reflection Surfaces for Uniform LED Illumination

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Solution Overview

Problem

Current LED light source mechanisms for telephone sets suffer from uneven illumination when using a single LED, as light is concentrated at the center, leaving the left and right ends poorly lit, and require costly diffusing agents to improve visibility of incoming-call indicators.

Innovation Solution

The LED light source mechanism employs conical-shaped reflection surfaces to diffuse light in three-dimensional directions, ensuring uniform illumination across a laterally long and wide area without the need for diffusing agents, by positioning the LED at the center and using a light guide part with conical and truncated-conical reflection surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a single LED is used as the light source, then cost is reduced, but illumination uniformity deteriorates due to light concentration at the center

Engineering Contradiction:
Improvenumber of LEDsVSAvoidillumination uniformity
Core Design Contradiction:
Quantity of substanceVSIllumination intensity

Solution Approach 1:

The invention transitions from a conventional planar light guide structure to a three-dimensional conical light guide structure. The conical shape with its sloped surfaces redirects light from the centrally positioned LED in multiple directions, achieving uniform illumination across the wide illumination surface while maintaining the cost advantage of using only one LED.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The invention changes the geometric parameters of the light guide structure by introducing conical shapes with specific slope angles. This parameter change enables the light to be distributed uniformly across the illumination surface, solving the illumination uniformity problem while keeping the LED quantity at one.

Inventive Principle:
Principle #35Parameter changes

2Area of stationary object

If the illumination surface is extended laterally to increase visibility, then the illuminated area increases, but illumination uniformity deteriorates as light cannot reach the left and right ends evenly

Engineering Contradiction:
Improveillumination surface areaVSAvoidillumination uniformity
Core Design Contradiction:
Area of stationary objectVSIllumination intensity

Solution Approach 1:

The conical light guide structure introduces a third dimension with its sloped surfaces, enabling light to reach the lateral ends of the extended illumination surface. The sloped angles are specifically designed to redirect light horizontally toward the left and right ends, achieving both wide coverage and uniform illumination simultaneously.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Illumination intensity

If diffusing agents are added to the light guide part to improve light diffusion, then illumination uniformity improves, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveillumination uniformityVSAvoidmanufacturing simplicity
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The invention replaces the chemical approach of using diffusing agents with a geometric/mechanical approach using conical structures with sloped surfaces. This substitution achieves light diffusion through precise geometric design rather than material additives, maintaining manufacturing simplicity while improving illumination uniformity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the geometric parameters of the light guide structure to conical shapes with optimized slope angles. This parameter optimization enables effective light diffusion and uniform illumination without requiring diffusing agents, thus avoiding the manufacturing complexity and cost associated with material modifications.

Inventive Principle:
Principle #35Parameter changes

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 configuration achieves uniform illumination from the central part to both ends of the illumination surface, reducing the need for diffusing agents and lowering costs while enhancing visibility and maintaining a clear, bright illumination state.

Implementation Method 1

conical-shaped reflection surfaces to diffuse light in three-dimensional directions

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3745692B1LED light source mechanism, telephone set, and method for forming LED light source
Publication Date: 2023.04.05 NEC PLATFROMS LTD
  • EP3745692B1 patent drawingFigure 1
  • EP3745692B1 patent drawingFigure 2A
  • EP3745692B1 patent drawingFigure 2B

AI summary

One LED (10) is used as a light source, i.e., an LED light source mechanism (50) that illuminates an illumination surface (11), the illumination surface being laterally long and wide in a left/right direction, in which a central axis of the LED (10) is disposed at a position on a center line vertically extending from a central part in the left-right direction of the illumination surface (11) in such a manner that the LED (10) faces the illumination surface (11), and two reflection surfaces are formed in a conical shape on a reflection surface forming place (12A) so as to surround the illumination surface (11), a light guide part, and the LED (10), and a center line of the conical shape is disposed on the central axis of the LED (10), the two reflection surfaces being configured to reflect light that is emitted from the LED toward an outside of the illumination surface (11). The two reflection surfaces are a first reflection surface (12a) having a conical shape, configured to reflect light from the LED (10) on an outer-surface side thereof, and a second reflection surface (12b) having a truncated-conical shape, the second reflection surface including openings for light on both upper and lower surfaces and configured to reflect light from the LED (10) on an inner-surface side thereof.