Lamp with Reflective Extraction Structures for Controlled Light Emission
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Solution Overview
Problem
Conventional lamps with lightguides and extraction structures emit light in a directionally undefined manner, making it difficult to achieve controlled lighting properties, particularly in applications requiring homogeneous light distribution.
Innovation Solution
A lamp design featuring a transparent sheet-like lightguide with optically coupled light sources and reflective extraction structures on its back surface, optimized to minimize light scattering, allowing for well-defined light emission and polarization, which enhances the perception of depth and light control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light scattering structures (diffuser foils, diffusive particles) are added to achieve homogeneous light distribution, then light extraction efficiency is improved, but light directionality and polarization control are lost
Solution Approach 1:
The back surface of the lightguide is segmented into multiple discrete reflective optical extraction structures (prisms or reflectors) arranged in a specific pattern. Each structure independently extracts light through total internal reflection, maintaining directional control while achieving homogeneous distribution across the lightguide surface.
Solution Approach 2:
The optical extraction structures are positioned at specific locations on the back surface rather than uniformly distributed. This local placement strategy allows precise control over light extraction zones, maintaining both directionality and homogeneous illumination by targeting specific areas where light guidance is needed.
2Area of stationary object
If conventional extraction structures are used to extract light from the lightguide, then light emission area is increased, but light emission direction becomes undefined
Solution Approach 1:
The reflective optical extraction structures utilize angled surfaces (typically 45 degrees) that redirect light at controlled angles. This geometric configuration maintains a well-defined emission direction while expanding the effective light emitting area across the lightguide surface.
Solution Approach 2:
Conventional diffusive methods are replaced with optical reflection principles. The extraction structures use total internal reflection and controlled refraction to direct light, substituting mechanical scattering with precise optical path control to maintain directionality.
3Ease of operation
If light scattering structures are removed to achieve well-defined light emission, then light directionality is improved, but light extraction efficiency decreases
Solution Approach 1:
Light sources are positioned and oriented before light enters the lightguide to optimize the initial light path. This preliminary configuration ensures that light enters the lightguide at angles that maximize total internal reflection at the extraction structures, maintaining high extraction efficiency without scattering elements.
Solution Approach 2:
The refractive index parameters of the lightguide material and extraction structures are optimized to enhance total internal reflection. By carefully selecting materials with appropriate refractive index differences, light extraction efficiency is maintained through optical reflection rather than scattering, preserving both directionality and intensity.
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 lamp achieves a well-defined light emission with enhanced polarization properties, creating a 3D effect and improved light control, allowing for better manipulation of lighting characteristics and reduced ambient light reflection, resulting in a high-contrast, non-reflective illumination.
Implementation Method 1
extraction structures comprise mirroring surfaces. By suitably positioning the mirroring surfaces, light that is guided in the lightguide by total internal reflection may be reflected such that it is able to leave the lightguide
Implementation Method 2
Depending on the index of refraction of the material of the lightguide, and on the desired exit angle, the angle of the mirroring surfaces with respect to the back surface may be selected
Data Source
AI summary
A lamp for emitting light, comprising a transparent sheet-like lightguide, with at least one light receiving side, a light emission front surface and a back surface opposite the front surface. The lamp further comprises a plurality of light sources, positioned in an array and optically coupled to at least one light receiving side. The back surface of said lamp comprises a plurality of optical extraction structures, for example provided in parallel curved lines. Furthermore, the lamp is substantially free from light scattering structures in a light path of the light to be emitted.