We present a simple freeform lens design method for an application to LED collimating illumination. The method is derived from a basic geometric-optics analysis and construction approach. By using this method, a highly collimating lens with LED chip size of 1.0 mm × 1.0 mm and optical simulation efficiency of 86.5% under a view angle of ± 5 deg is constructed. To verify the practical performance of the lens, a prototype of the collimator lens is also made, and an optical efficiency of 90.3% with a beam angle of 4.75 deg is measured.
A paper design is the design, which has the theoretical design only and without considering the manufacturing errors. Therefore, the final performance of the lens assembly might degrade far apart from the paper design. An example of wide-angle lens tolerance analysis is presented. The numerical and graphical aberration degradation analysis shows the useful method to decide the individual lens element manufacturing tolerance.
INTROUDUCTIONThe duty of lens designer is to make sure that the design lens has met all specifications at the end. Occasionally, this task has to gather all participants' efforts to achieve. Before lens designer releasing the prescription to the workshop, it is better to communicate the design with mechanical engineers and craft persons to avoid the beauty but not practical designs. Under this point of view, we have presented a wide-angle lens example to show the degradation of image performance due to the tolerance effect.Literatures, based on the wavefront and diffraction analysis 1-3 or the intuitive display of the aberrations of perturbation 4 are listed in the references.
THE PROCEDURE OF TOLERANCINGThe procedure of tolerance a wide-angle lens is described in the following:1. Select an appropriate set of tolerance for optical and mechanical components 2. Assign compensators and adjustable range of compensators, e.g. back focus distance 3. Select an appropriate criteria, such as RMS spot size or MTF
Wide-angle lenses and fish-eye lenses are broadly applied to various fields, including monitoring systems, rearview camera, event data recorders, and projectors, aiming to acquire enough visual field with the lens design on the limit sensing area of CCD. The wide-angle lenses, which apply four pieces of glass lenses with the angle of view 100 degree, the distortion controlled within 40%, and MTF in the angle of view above 40lp/mm, are proposed in this study. A piece of aspheric lens and three pieces of spherical lenses are combined for the cost-effective wide-angle lens.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.