Formation of Photodetector Optimal Signal in Optical Control Systems

• Дата: 2022
• Автори: Антонов, Є. Є., Зенін, В. М., Лапчук, А. С., Петров, В. В., Токалін, О. О.
• Формат: Стаття
• Мова: Ukrainian
• Опубліковано: Інститут проблем реєстрації інформації НАН України 2022
• Теми: four-plane photodetector; microrelief structure; direction finding characteristic; mode-ling of focusing optics; чотирьохплощинний фотодетектор; мікрорельєфна структура; пеленгаційна характеристика; моделювання фокусуючої оптики
• Онлайн доступ: http://drsp.ipri.kiev.ua/article/view/262693
• Назва журналу: Data Recording, Storage & Processing

An algorithm for modeling the signal shape of a four-quadrant photodetector when moving an axisymmetric light spot on the detector surface has been developed. The form of direction finding characteristics of the photodetector is calculated for some schemes of illumination of the sensitive surface of the detector, which are used to create optical automatic control systems, in particular the systems for motion control and positioning of various objects. It is well-known that any lenses or Fresnel lenses concentrates the light intensities in the center of formed image. For signal processing systems it is necessary to convert a parallel light beam into a uniformly illuminated light circle. Such applications are often used in the optical sensor systems such as the distance laser meters or in the monitoring devices for automatically adjusting the output signal from the four-quadrant photodetector. Now a method for modeling microrelief structures is proposed for creating focusing devices with the flat conical working faces that form a uniformly illuminated light circle with a bright illuminated light ring in its periphery. Some samples of such specified focusing micro-prism devices with illumination distribution of the light spot in the form of circle and ring, which are made according to the results of modeling by the diamond cutting technique, are experimentally investigated. A feature of focusing structures created by the diamond cutting technique is a discrete change in the refractive angles of micro-prismatic zones, resulting in the discreteness of the images formed in the focus. This is a main difference from Fresnel focusing optics with aspherical convex circular surfaces, when the angles of refraction change continuously. In the manufacture of such new devices by the diamond cutting method it is possible to obtain almost mirror working surfaces of a high optical quality. However, the size of such conical refracting zones should not be too large to reduce the discreteness of the formed images, so the new specified focusing micro-prisms are made from several identical prismatic elements. The study of optical and lighting characteristics of experimental samples of focusing elements was carried out, the results of which showed full compliance of experimental data with the obtained theoretical characteristics. Developed specialized concentrator lenses that transform the transmitted light fluxes in the required way can be effectively used in moving object tracking systems instead of the usual pair of diffuser-focusing elements.