Free-form lens indirect lighting ceiling coverage

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Solution Overview

Problem

Conventional lamps with indirect lighting struggle to illuminate a large area of the ceiling when the distance between the lamp and the ceiling is small, as they rely solely on illuminating the top of the lamp towards the ceiling, resulting in inadequate coverage.

Innovation Solution

Incorporating a free-form lens above the LED lighting means, which utilizes a combination of light refraction and total reflection to broaden the light distribution, allowing the lamp to effectively illuminate a larger ceiling area by deflecting light through a wide angle without loss, even at a short distance from the ceiling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a conventional LED lighting means is used to generate indirect lighting by emitting light upwards towards the ceiling, then the lamp structure is simple and compact, but the light distribution is limited and cannot illuminate a large area of the ceiling when the distance is small

Engineering Contradiction:
Improveceiling illumination areaVSAvoidoptical system complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

A free-form lens is introduced as an intermediary optical element between the LED light source and the ceiling. This lens mediates the light distribution by combining refraction and total reflection to broaden the illumination area without requiring multiple LEDs or complex arrangements, thus resolving the contradiction between expanding ceiling coverage and maintaining system simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the optical parameters of the lighting system by using a free-form lens with specific refractive index and surface geometry. This transforms the light distribution pattern from a conventional narrow beam to a broadened illumination area, enabling effective indirect lighting at small distances from the ceiling while maintaining a single LED source.

Inventive Principle:
Principle #35Parameter changes

2Area of stationary object

If multiple LEDs are arranged on the surface to emit light at a shallow angle to the ceiling, then the indirect lighting coverage is improved, but the device complexity increases and LEDs must be arranged at the edge of the housing

Engineering Contradiction:
Improveceiling illumination areaVSAvoidassembly and cleaning ease
Core Design Contradiction:
Area of stationary objectVSEase of operation

Solution Approach 1:

The free-form lens performs multiple functions simultaneously: it refracts light to broaden distribution, reflects light through total internal reflection, and maintains a compact single-point LED arrangement. This multi-functionality eliminates the need for multiple edge-mounted LEDs, simplifying assembly and cleaning while achieving broad ceiling illumination.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

Instead of using multiple physical LEDs arranged at edges, the patent uses a single central LED with a free-form lens that optically replicates the effect of multiple light sources. The lens creates virtual image copies of the light source, producing broad illumination patterns equivalent to multiple LEDs but with simpler mechanical assembly and easier maintenance.

Inventive Principle:
Principle #26Copying

3Length of stationary object

If the lamp is installed at a small distance from the ceiling for compact design, then the overall height is reduced, but the indirect lighting coverage is insufficient

Engineering Contradiction:
Improvelamp heightVSAvoidceiling illumination area
Core Design Contradiction:
Length of stationary objectVSArea of stationary object

Solution Approach 1:

The free-form lens is made from transparent plastic material (such as PMMA or polycarbonate) that combines appropriate refractive index and optical clarity. This composite optical material enables the lens to effectively broaden light distribution at close distances from the ceiling, maintaining compact lamp height while achieving sufficient illumination area through the material's optical properties.

Inventive Principle:
Principle #40Composite materials

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 free-form lens enables the lamp to achieve broad and uniform indirect lighting coverage of the ceiling, maintaining a compact design and easy assembly and cleaning, while allowing for both indirect and direct lighting capabilities.

Implementation Method 1

the free-form lens ensures a broader light distribution through a combination of light refraction and total reflection

Methodology Applied
Scientific EffectLight refraction: Refraction

Implementation Method 2

the light from the LED is at least partially totally reflected on the first optical surface and is emitted in a direction to a light exit surface

Methodology Applied
Scientific EffectTotal reflection: Total Internal Reflection

Data Source

PatentEP3199867B1Lamp with indirect lighting
Publication Date: 2019.07.10 SITECO GMBH
  • EP3199867B1 patent drawingFigure 1
  • EP3199867B1 patent drawingFigure 2~3
  • EP3199867B1 patent drawingFigure 4~5

AI summary

The invention relates to a luminaire with a light source comprising at least one LED for generating indirect lighting, wherein the light source is provided on one side of the luminaire which, in the mounted state of the luminaire, points towards the ceiling, wherein a free-form lens is arranged above the light source and the free-form lens has optical surfaces which are arranged to broaden the light distribution of the indirect lighting compared to the light distribution of the LED itself by means of a combination of light refraction and total internal reflection.REFERENCE SYMBOL LIST 1 Free-form lens 2 Housing support 3 LED for indirect component 4 Inverted V-shaped light entry surface 5 First V-shaped optical surface 6 Light exit surface 7 Optical surface 8 Crossing light beams 9 Light exit surface 10 Light exit surface 12 Retaining section 14 Complementary retaining section on the luminaire housing 21 LVK of the indirect component in the C0/180 plane 22 LVK of the indirect component in the C90/270 plane 30 LED for direct component.