Curved L-Shaped Light Guide for Direct and Indirect Downlighting
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Solution Overview
Problem
Conventional downlight luminaires struggle to meet the new lighting requirements of DIN EN 12464-1:2021-11 standard for office areas, which necessitate an illuminance average value of 100lx on the ceiling, and existing solutions for indirect lighting are mechanically complex and prone to wear.
Innovation Solution
A downlight luminaire design featuring a light guide element with a curved L-shape that integrates a light coupling surface and an inclined decoupling surface, allowing for flexible and efficient direct and indirect illumination without mechanical adjustments, utilizing LEDs and a light mixing chamber for homogeneous light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional downlight luminaires are used for direct illumination, then the lighting function is simple and reliable, but the illuminance average value on the ceiling cannot meet the new lighting requirements of DIN EN 12464-1:2021-11 standard
Solution Approach 1:
The luminaire is segmented into multiple independent light sources arranged in specific patterns (e.g., central light source for direct illumination, peripheral light sources for indirect illumination). This segmentation allows each light source to serve specific lighting zones, enabling the system to meet ceiling illuminance requirements while maintaining configuration flexibility.
Solution Approach 2:
The invention transitions from traditional single-direction (downward) illumination to multi-directional illumination by incorporating upward-pointing light sources. This dimensional change enables indirect lighting that reflects off the ceiling, thereby increasing the illuminance average value on the ceiling while providing versatile lighting configurations.
2Illumination intensity
If mechanical moving light redirecting elements are used to provide indirect lighting, then the lighting requirements can be met, but the system becomes susceptible to wear and requires considerable effort for adjustment
Solution Approach 1:
The invention replaces mechanical moving light redirecting elements with fixed optical structures such as reflectors and light guides. These static components achieve indirect lighting through optical design rather than mechanical movement, eliminating wear and tear associated with mechanical systems while maintaining reliable indirect illumination.
Solution Approach 2:
The invention introduces intermediary optical elements such as reflectors positioned between light sources and the ceiling environment. These intermediaries redirect light optically without requiring mechanical movement, providing a reliable and maintenance-free solution for achieving indirect lighting that meets ceiling illuminance requirements.
3Adaptability or versatility
If mechanical adjustment is used to configure indirect lighting, then the lighting can be adapted, but the adjustment process requires considerable effort and time
Solution Approach 1:
The lighting configuration is predetermined during the manufacturing process with light sources positioned in optimal locations and fixed optical elements pre-aligned. This preliminary action eliminates the need for time-consuming on-site mechanical adjustments, allowing the luminaire to be installed and immediately configured for both direct and indirect illumination according to the new lighting requirements.
Solution Approach 2:
The luminaire design incorporates multiple light sources with different orientations (upward and downward) that can simultaneously provide both direct and indirect illumination. This universal design enables the single luminaire to fulfill multiple lighting functions without requiring separate adjustable components, thereby reducing configuration time and effort while maintaining adaptability to various lighting requirements.
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 luminaire achieves both direct and indirect illumination with adjustable proportions, reducing mechanical wear and maintenance needs, while ensuring sufficient light emission to meet regulatory standards.
Implementation Method 1
a light guide element, whereas the light guide element is integrally formed and essentially flange-shaped with a curved L shape in a radial section, wherein the light guide element has a light coupling surface being positioned within the light mixing chamber and facing the light source board
Implementation Method 2
wherein the light guide element has an inclined light decoupling surface at a distal end region of the light guide element, whereas the inclined light decoupling surface of the light guide element is positioned outside of and lateral to the light mixing chamber
Implementation Method 3
a light mixing chamber for homogeneous light mixing subsequent to the light source board in the general light emission direction
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
A downlight luminaire (1) having a light emission for direct illumination (Ld) and a light emission for indirect illumination (Li), whereas the luminaire (1) comprises: a light source board (100), having multiple light sources (110, 111, 112) for light emission in a general light emission direction (Lg); a light mixing chamber (990) for homogeneous light mixing subsequent to the light source board (100) in the general light emission direction (Lg), wherein the light mixing chamber has lateral walls (950, 700); a translucent cover plate (300) that encloses the light mixing chamber (990) in the general light emission direction (Lg); and a light guide element (200), whereas the light guide element (200) is integrally formed and essentially flange-shaped with a curved L shape in a radial section. Hereby the light guide element (200) has a light coupling surface (201) being positioned within the light mixing chamber (990) and facing the light source board (100), and the light guide element (200) has an inclined light decoupling surface (230) at a distal end region (220) of the light guide element (200). The inclined light decoupling surface (230) of the light guide element (200) is positioned outside of and lateral to the light mixing chamber (990), whereas light being coupled into the light guide element (200) via the light coupling surface (210) is partially directed towards the inclined light decoupling surface (230) within the light guide element (200). Hereby light emitted via the translucent cover plate (300) is emitted for direct illumination (Ld) substantially in the general light emission direction (Lg) and light emitted via the inclined light decoupling surface (230) is emitted for indirect illumination (Li) and substantially emitted in an indirect light emission direction (Lc) being a direction contrary to the general light emission direction (Lg).