A dual view capsule endoscopic (DVCE) lens is proposed with front view and back view functions. This is a hybrid lens with a catadioptric mirror and an aspherical surface to support both view functions. The field of view (FOV) for the front view function is 90 degrees. The FOV for the back view function is 260 to 290 degrees. The TV distortion for the front view and back view function is under 30% and 25%. The corner relative illuminations for the two view functions are above 0.53. The Modulation Transfer Function (MTF) performance at the Nyquist Frequency for the two view functions can be kept above 0.35, even under tolerance they can remain above 0.2. Moreover, the telecentric conditions at the image plane of the DVCE system can support constant magnification through focusing. This condition can reduce the measurement error by slightly defocusing of the lens. Thus, the two view functions can offer physicians a wide viewing angle to deal with lesions over the fold.
An anti-glare luminaire design is proposed to reduce the effect of glare and the multi-shadow while preserving high optical efficiency, high illumination uniformity and low unified glare rating (UGR). Comparison to the traditional direct light emitting diode (LED) luminaire in optical simulations showed an enhancement of the illumination uniformity from 64.9% to 80.0%. The optical efficiency was 79.5%, and the UGR value was controlled under 18.8. For the actual measurement, the finished product had an illumination uniformity of 77.0%, optical efficiency of 76.0%, UGR value of 19.0, and efficacy of 81.4 lm/w. Through this design, the lighting performance was greatly enhanced.
In this paper, we present a novel light separator with the ability to enhance the contrast ratio and maintain the optical efficiency in a digital light processing (DLP) projection system. The working theorem for the novel light separator is derived as well. In this novel light separator design, the ghost ray is directed away from the projection lens by a total internal reflection surface. Since the ghost ray does not even enter the projection lens, the contrast ratio enhancement is more effective than that achieved by an asymmetrical stop. Compared with the conventional method, the full-on/full-off (FO:FO) contrast ratio is increased from 921:1 to 46347:1 and the American National Standards Institute (ANSI) contrast ratio is increased from 177:1 to 295:1. The imaging system efficiency can maintain at 79.8% under the contrast ratio enhancement process.
In this paper, a novel light separator with contrast ratio enhancement but maintaining the optical efficiency of the DLP projection system is proposed. The main capability of the novel light separator is to direct the uncontrolled light away from the image system. The working theorem for the novel light separator is derived as well. Uncontrolled light is kept away from the image system by a total internal reflection surface, thereby effectively improving the image quality. Compared with previous work, the FO:FO contrast ratio can be improved from 46347:1 to 48250:1, the ANSI can be improved from 295:1 to 306:1, while the image system efficiency remains at 76.2%.
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