Design, fabrication, and characterization of a tunable LED-based illuminator using refractive freeform arrays

Shadalou, Shohreh; Gurganus, Dustin; Cassarly, William J.; Davies, M.A.; Suleski, Thomas J.

doi:10.1364/oe.474842

Cited by 5 publications

(4 citation statements)

References 19 publications

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“…in the range of 10%~18%. 22 Fig. 3 summarize the AD values measured for the 8.5º cavity vs. the extended cavity, with different mixing rod lengths and surface conditions as well as diffuser types and configurations.…”

Section: Resultsmentioning

confidence: 99%

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High-efficiency, low-speckle contrast white laser lighting via multi-stage scattering and photon recycling

Liu

Wang

Carver

et al. 2023

Preprint

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Lighting consumes > 10% of the global electricity. White laser lighting, utilizing either direct color mixing or phosphor-conversion, can potentially boost the efficiency well beyond existing light emitting diodes (LEDs) especially at high current density. Here we present a compact, universal packaging platform for both laser lighting schemes, which is simultaneously scalable to wavelength division multiplexing for visible light communication. Using commercially available laser diodes and optical components, low-speckle contrast ≤ 5% and uniform illumination is achieved by multi-stage scattering and photon recycling through a mixing rod and static diffusers in a truncated-pyramidal reflective cavity. We demonstrate a high luminous efficacy of 274 lm/Wo for phosphor-converted laser lighting and 150 lm/Wo for direct red-green-blue laser mixing, respectively, in reference to the input optical power. In the former case, the luminous efficacy achieved for practical lighting is even higher than most of the previous reports measured using integrating spheres. In the latter case of direct laser color mixing, to our best knowledge, this is the first time to achieve a luminous efficacy approaching their phosphor-conversion counterparts in a compact package applicable to practical lighting. With future improvement of blue laser diode efficiency and development of yellow/amber/orange laser diodes, we envision that this universal white laser package can potentially achieve a luminous efficacy > 275 lm/We in reference to the input electrical power, ~ 1.5x higher than state-of-the-art LED lighting and exceeding the target of 249 lm/We for 2035.

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Section: Resultsmentioning

confidence: 99%

“…3 is comparable to LED-based illuminators. 22 Light Extraction Efficiency ηex. We then verify that the light extraction efficiency ηex is notably enhanced in the extended cavity structure, as theoretically predicted in Table 3 and experimentally demonstrated in Fig.…”

Section: Resultsmentioning

confidence: 99%

High-efficiency, low-speckle contrast white laser lighting via multi-stage scattering and photon recycling

Liu

Wang

Carver

et al. 2023

Preprint

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“…They also simplify the optical system structure by reducing the number of optical components in the optical system [2]. As a result, they are widely used in optical imaging systems [3][4][5][6][7][8] and non-imaging systems [9][10][11][12][13]. The development of ultra-precision machining technology has provided many creative challenges for the construction of high-precision optical freeform surfaces [14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

A Toolpath Planning Method for Optical Freeform Surface Ultra-Precision Turning Based on NURBS Surface Curvature

Wang,

Bai,

Gao

et al. 2023

Machines

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As the applications for freeform optical surfaces continue to grow, the need for high-precision machining methods is becoming more and more of a necessity. Different toolpath strategies for the ultra-high precision turning of freeform surfaces can have a significant impact on the quality of the machined surfaces. This paper presents a novel toolpath planning method for ultra-precision slow tool servo diamond turning based on the curvature of freeform surfaces. The method analyzes the differential geometric properties of freeform surfaces by reconstructing NURBS freeform surfaces. A mathematical model is constructed based on the parameters of different positions of the freeform surface, toolpath parameters, and tool residual height. Appropriate toolpath parameters can be calculated to generate the optical freeform ultra-precision slow tool servo diamond turning toolpath. Compared with the toolpaths generated by the traditional Archimedes spiral method, the ultra-precision slow tool servo diamond turning toolpath planning method proposed in this paper can generate more uniform toolpaths on the freeform surfaces and keep the residual tool height within a small range.

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“…A common technique for collimating the light and evenly distributing energy is using a refractive lens or reflector group to change the direction of light [6][7][8][9][10][11][12][13]. The primary problem with this technique is that too many optical elements in these methods lead to an excessive volume of the optical system.…”

Section: Introductionmentioning

confidence: 99%

Design of a high‐power collimating optical system based on Fresnel lenses

Sun,

Zhang,

Wang

et al. 2023

Luminescence

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In light‐emitting diode (LED) illumination (e.g., LED maritime lighting for ships), creating a uniform light environment for optical systems is an important challenge. In this study, we present a high‐power collimating system based on Fresnel lenses, which allows high‐brightness LED illumination in the earlier‐mentioned remote distance. The work presented in this article focuses on improving the power, compacting the optical structure, and promoting the brightness of the spot. To prove the claims, the system with a total power of 1 kW is designed. The system consists of a 27 W LED array, a freeform surface lens array, and a confocal Fresnel lens array. In comparison with the traditional optical system, the optical structure shortens from 390 to 120 mm, and the divergent angle decreases from 3° to 2. Meanwhile, the illuminance of the system is obtained as high as 230 lx at the near field of 200 m and 3.0 lx at the far field of 1.5 nautical miles. This new method provides a practical and effective way to solve the problem of low power, insufficient illuminance, and long optical structure for LED array illumination, which is suitable for remote illumination and guidance of ships.

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Design, fabrication, and characterization of a tunable LED-based illuminator using refractive freeform arrays

Cited by 5 publications

References 19 publications

High-efficiency, low-speckle contrast white laser lighting via multi-stage scattering and photon recycling

High-efficiency, low-speckle contrast white laser lighting via multi-stage scattering and photon recycling

A Toolpath Planning Method for Optical Freeform Surface Ultra-Precision Turning Based on NURBS Surface Curvature

Design of a high‐power collimating optical system based on Fresnel lenses

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