Laser Light Guide Geometry for Uniform Color in Compact Illumination
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Solution Overview
Problem
Illumination devices using semiconductor laser sources face challenges in achieving uniform color chromaticity and size reduction due to the high directivity of light emission, which requires longer light guides for effective mixing of light beams of different wavelengths.
Innovation Solution
The illumination device incorporates a light guide with specific geometric configurations, including tilted planes and recesses, and arranges semiconductor laser elements to emit light at different wavelengths in a way that reduces the distance for mixing and thickness, ensuring efficient light propagation and uniform chromaticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a semiconductor laser device is used as the light source, then the illumination device can achieve high brightness and color purity, but the length of the light guide required for light beams of respective colors to sufficiently mix increases
Solution Approach 1:
The patent introduces tilted planes and recesses into the light guide structure, transforming the light propagation from a simple linear path to a multi-dimensional path with varying angles. This dimensional change in light propagation allows for increased mixing efficiency within a shorter overall length, resolving the contradiction between brightness maintenance and light guide length reduction.
Solution Approach 2:
The tilted planes and recesses create curved/reflected light paths instead of straight-line propagation. By bending the light path through angled surfaces, the light beams traverse a more complex trajectory that enhances mixing of different wavelengths while keeping the physical light guide length shorter.
2Length of stationary object
If the light guide length is reduced to downsize the illumination device, then the device becomes more compact, but the light beams of respective colors cannot sufficiently mix
Solution Approach 1:
By incorporating tilted planes and recesses, the patent creates a multi-dimensional light propagation path that increases the effective mixing distance within a shorter physical length. This allows compact device design while maintaining sufficient light mixing for color uniformity.
Solution Approach 2:
The light guide is segmented into multiple sections with different geometric features (tilted planes, recesses, varying thicknesses). Each segment contributes to light mixing at different stages, ensuring progressive and efficient color uniformity achievement along the shortened light guide path.
3Length of moving object
If the light guide thickness is reduced, then the illumination device becomes thinner and more compact, but the light mixing efficiency decreases
Solution Approach 1:
The tilted planes and recesses create curved light paths that increase the optical path length within the thin light guide. This allows light beams to mix more effectively despite the reduced physical thickness, maintaining mixing efficiency while achieving a thinner device profile.
Solution Approach 2:
The patent uses angular deviations and three-dimensional structural features to compensate for the reduced thickness. By directing light at various angles through tilted surfaces, the effective mixing path is extended in directions other than the thickness dimension, preserving mixing efficiency.
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 improves color uniformity and downsizes the illumination device by reducing the distance needed for light mixing and the thickness of the light guide, enhancing performance and compactness.
Implementation Method 1
a light guide having a first plane, a second plane opposed to the first plane and substantially parallel to the first plane, a side plane, a first tilted plane located between the side plane and the first plane and tilted to the first plane, and a second tilted plane located between the side plane and the second plane and tilted to the second plane
Data Source
AI summary
According to one embodiment, an illumination device includes a light guide having a first plane, a second plane, a side plane, a first tilted plane, and a second tilted plane, an angle formed between the side plane and the first tilted plane and an angle formed between the side plane and the second tilted plane being acute angles, a first semiconductor laser element including a first light emitting part, and a second semiconductor laser element including a second light emitting part. The first light emitting part is opposed to a first intersection part of the side plane and the first tilted plane, and the second light emitting part is opposed to a second intersection part of the side plane and the second tilted plane.