A highly efficient regular curved retroreflector is proposed to meet the requirements of the US Society of Automotive Engineers (SAE) regulations. It is demonstrated that 28% higher retroreflection efficiency and 33% more working area can be accomplished with the new designed retroreflector when compared with the commercial ones used in modern vehicles.

In fields such as biology, archeology, and industry, underwater photogrammetry can be achieved using consumer-grade equipment. However, camera operations underwater differ considerably from those on land because underwater photogrammetry involves different optical phenomena. On the basis of the requirements and specifications of the marine vessel Polaris, we developed a novel underwater camera with prime and zoom lenses and a high resolving power. The camera can be used in the spectrum in shallow water and the blue–green spectrum in deep water. In the past, ordinary cameras would be placed in waterproof airtight boxes for underwater photography. These cameras were not optimized to the underwater spectrum and environment, resulting in no breakthroughs in resolving power. Furthermore, the use of the blue spectrum greatly increases during underwater and particularly deep-water surveying. Chromatic aberration and focus-point displacement generated by the shift from the shallow-water spectrum to the blue–green spectrum in deep water makes universal underwater photography even more difficult. Our proposed optical design aimed to overcome such challenges for the development of a high-resolution underwater surveying camera. We designed a prime lens and a zoom lens. We adopted a waterproof dome window on the outer surface as the basic structure and optimized it in accordance with the conditions of different water depths and spectra to obtain distortion within ±2% and high-resolution underwater imaging quality. For the zoom lens design, we employed a genetic algorithm in Zemax to attenuate chromatic aberration as a kind of extended optimization. This novel optical design that can be used in all waters is expected to greatly reduce the volume and weight of conventional underwater cameras by more than 50% and 60%, respectively, and increase their resolving power by 30–40%.

The galvanometer scanning system plays a crucial role in modern laser material processing. With the development of this industry, the requirements for galvanometer scanners are getting higher and higher, especially to overcome the inherent disadvantages that still exist, such as image distortion, marking speed and accuracy in state-of-the-art scanning systems. In this paper, a single-axis optical scanner using two galvanometers in combination with one f-theta telecentric lens and a 343 nm femtosecond pulse laser source is proposed as a new approach for enhancing the precision of laser micromachining technology. The additional second galvanometer is used to manipulate the output laser beam of the first galvanometer to the path with less lens aberration to enhance the telecentricity correction and the effective scanning area. This is based on the international standard regulation ISO (the International Organization for Standardization) 11145:2018 requirements in optics and photonics, in which an important criterion is for the roundness of the focused beam spot to be greater than 87% to determine the effective working length of the proposed scanning system compared to the conventional scanning system. It is demonstrated by optical simulations and real optical experiments that the effective working length can be increased by 3.6 mm, corresponding to 8.1% of the effective scanning field, to achieve a laser material processing system with ISO standard. The damped least squares (DLS) algorithm in optical design software ZEMAX is used to optimize the deflected angle of the two galvanometers to obtain the optimal incident position of the f-theta lens.

To enhance driving safety at night, a new freeform-surface street light luminaire was proposed and evaluated in this study that meets the requirements of the International Commission on Illumination (CIE) M3 class standard for road lighting. The luminaire was designed using simulations to optimize the location of the bulb according to the requirements of the standard. The light source IES file was experimentally obtained for the optimized luminaire prototype with a 150 W ceramic metal halide lamp using an imaging goniophotometer. The trial road lighting simulation results computed by the lighting software DIALux indicated that the proposed luminaire provided an average road surface brightness of 1.1 cd/m² (compared to a minimum requirement of 1.0 cd/m²), a brightness uniformity of 0.41 (compared to a minimum requirement of 0.4), a longitudinal brightness uniformity of 0.64 (compared to a minimum requirement of 0.6), and a glare factor of 7.6% (compared to a maximum limit of 15%). The findings of the image goniophotometer tests were then confirmed by the results of a certified mirror goniophotometer test conducted by the Taiwan Accreditation Foundation (TAF). The results of this study can be used to provide improved street lighting designs to meet enhanced international standards.

We propose and demonstrate, using optical experiments, a new reflex reflector structure called SuperPin Plus. The structure is composed of special pin groups with dihedral-angle offsets in corner cubes. One of the specular features brought by this new design is that it can comply with both the US SAE (US Society of Automotive Engineers) standard and the EU ECE (Economic Commission for Europe) standard, so that manufacturing costs of reflex reflector for both European and American automobile markets can be reduced. By using genetic algorithms for optimization, the angles and the positions of the pins, which are the building elements of corner cube reflectors, serve as the parameters to tune up the performance of the SuperPin Plus curved reflex reflector. Compared with conventional ECE flat regular retro-reflectors, we found that not only can we achieve a 41% higher retro-reflection efficiency with the ECE SuperPin Plus flat reflex reflector, but that SuperPin Plus can also act as a reflex reflector within SAE standards. In addition, we demonstrate that the retro-reflection efficiency is 30.5% higher (SAE standard) and 42.7% higher (ECE standard), and that a 32% increase in working area can be achieved if double pin groups are used to construct the corner cubes instead of a single pin arrangement, in a curved SuperPin Plus reflex reflector.

A new, highly efficient curved reflex reflector is proposed to meet the requirement of EU ECE (Economic Commission for Europe) regulations based on the commercial design provided by an automotive company which has been in mass production. We used double pins with corner cubes which served as the building element of a SuperPin curved retro-reflector to enhance reflectivity performance. Our experiment outcomes indicated 46% higher retro-reflection efficiency and 33% larger working areas compared with the commercial design.