A simple design of uniform LED illumination using catadioptric collimator and freeform lenslet array

We introduce a compact lenslet array principle that takes advantage of freeform optics to deploy a light distributor, beneficial for highly efficient, inexpensive, low energy consumption light-emitting diode (LED) lighting system. We outline here a simple strategy for designing the freeform lens that makes use of an array of the identical plano-convex lenslet. The light is redistributed from such lenslet, hinging on the principle of optical path length conservation, and then delivered to the receiver plane. The superimposing of such illumination area from every lenslet occurs on the receiver plane, in which the non-uniform illumination area located in the boundary should have the same dimension as the size of the freeform lenslet array. Such an area, insofar, is negligible due to their small size, which is the crux of our design, representing a large departure from the former implementations. Based on simulations that assess light performance, the proposed design exhibited the compatibility for multiple radiation geometries and off-axis lighting without concern for the initial radiation pattern of the source. As simulated, the LED light source integrated with such proposed freeform lenslet array revealed high luminous efficiency and uniformity within the illumination area of interest were above 70% and 85%, respectively. Such novel design was then experimentally demonstrated to possess a uniformity of 75% at hand, which was close to the simulation results. Also, proposed indoor lighting was implemented in comparison with the commercial LED downlight and LED panel, whereby the energy consumption, number of luminaires and illumination performance were assessed to show the advantage of our simplified model.

High-precision Shack-Hartmann wavefront sensing with a multi-focal diffraction Taiji-lenslet array

A Hartmann wavefront sensor is a type of wavefront detection instrument that has been widely used in various fields. Traditional Hartmann wavefront sensors usually comprise a monofocal refraction lenslet array to segment the wavefront at the entrance pupil. Each wavelet is focused at the focal plane along the projection of the lenslet, forming the foci array. Unlike the multifocal self-interference Taiji-lenslet array, a type of multifocal diffraction Taiji-lenslet array was proposed in this study to improve the measurement accuracy using the weighted centroid location algorithm of these multifocal spots, where the latter is more easily designed than the former. An optical experiment was implemented using the multifocal diffraction Taiji-lenslet array to verify its effectiveness. As a type of diffractive lens, a large-aperture Taiji-lenslet array can be easily fabricated via lithography, which has great potential for application in the measurement of large-scale laser beams and optical elements.

Beam Pre-Shaping Methods Using Lenslet Arrays for Area-Based High-Resolution Vehicle Headlamp Systems

High-resolution light distributions are lately in demand for vehicle headlamp systems as an innovative lighting approach. This lighting approach can realize functionalities, such as precise glare avoidance and on-road projection, which are useful for improving traffic comfort and safety. For achieving the required high-resolution light distribution, area-based projection technologies, such as DMD, LCD, and LCoS, are considered to be integrated into such headlamps. These projection devices demand rectangular illumination areas with specific light distributions to fulfill the requirements for illumination efficiency and performance in headlamp systems. Lenslet arrays, based on the principle of Köhler illumination, can effectively homogenize the light and shape it into rectangular shapes simultaneously. Such components are widely used in projection applications. However, they also show functional potentialities to be applied in high-resolution headlamps. This paper explains the design principles and methods of lenslet arrays for beam pre-shaping in headlamp systems. It validates the homogenization using a self-designed and manufactured lenslet array in a demonstrator in the first place. Afterward, this paper introduces two new methods for the centralized beam shaping required by some headlamps. These methods are validated by optical simulations.

Enormous unique range autorefraction for tracking

Wavefront detecting with a slim diffuser has developed as a potential minimal effort option in contrast to a lenslet exhibit for aberrometry. Diffuser wavefront sensors (DWS) have recently depended on following dot removal and thus require intelligent brightening. Here we show that removal of harsh examples can be followed for assessing wavefront angle, empowering the utilization of muddled light sources and enormous dynamic-run wavefront estimations. We contrast the accuracy of a DWS with a Shack-Hartmann wavefront sensor (SHWS) when utilizing intelligent, somewhat reasonable, and incomprehensible light, in the utilization of autorefraction. We initiate round and tube shaped mistakes in a model eye and utilize a staggered Demon's non-unbending enrollment calculation to assess burning removals comparative with an emmetropic model eye. When contrasted with round mistake estimations with the SHWS utilizing in part cognizant enlightenment, the DWS shows a $\sim$5-crease improvement in powerful range (- 4.0 to +4.5 D versus - 22.0 to +19.5 D) with not exactly a large portion of the decrease in goals (0.072 versus 0.116 D), empowering a $\sim$3-overlay increment in the quantity of resolvable remedies (118 versus 358). Notwithstanding being 40x lower-cost, the one of a kind, non-intermittent nature of the burning example framed by a diffuser empowers a bigger powerful scope of abnormality estimations contrasted with a lenslet array