Zhicheng Weng

All reflective zoom systems for infrared optics

The results of design effort for infrared zoom systems using all reflective aspheric surfaces are described. Issues such as the paraxial design theory and aberration balancing are discussed in detail. Two all reflective zoom optical systems are disclosed clearly. Both of them are to be used with uncooled infrared detectors. The first design is an unobscured three mirror zoom system without any intermediate image, and the second is a three mirror system with central obscuration which forms an intermediate image. With the design theory further developed, this kind of systems can be designed for cooled infrared detectors, for which cold stop matching is an important issue.

Design of infrared afocal zoom system

The design method and result are described for an infrared afocal zoom system. Its zoom ratio is 4, and the corresponding field of view is 3°~12°. The working waveband is from 7.5μm to 10.5μm, and its total length is required to be no more than 350mm. The final optical system consists of 7 elements, with aspheric surfaces and a diffractive optical element. It achieves diffraction-limited imaging at the far infrared waveband. Two conclusions can be drawn from the design. (1) Using diffractive optical elements in the design of an infrared optical system is an effective approach to control color aberrations, which eliminates the need to use exotic and expensive materials and helps to reduce the cost of the system; (2) Functions such as changing the field-of-view, focusing for objects at finite distances and athermalizing the system can be achieved by axially moving a single element in the system.

Design of compact, high-resolution optical system for space and analyze stray light

This paper describes the results of the design effort for a three-mirror anastigmatic system (TMAS) and its stray light analyzing. The system’s focal length is 4000mm and the relative aperture is f/10, it’s total length is nearly f’/3~f’/4 and field of view (FOV) is 30 × 10. The final optical system is a three-mirror unobscured telescope. It is telecentric and achieves diffraction-limited imagery at visible wavelengths. After analyzing the stray light used the Light Tool software, finally We can draw two conclusions: 1) design of unobscured optical system is still best approached using fundamental optical design principle; 2) time spent in careful analyzing the stray light and a higher probability of success for the assembled system.

Design of zoom lens with binary optics

Binary optics element (BOE) used to correct the aberrations of zoom lens, especially to control secondary spectrum in apochromatic zoom lens, are considered. Principles and methods are presented. The advantages in improving image quality and simplifying construction are illustrated through the design example.

Design of a three field-of-view IR system

The design method and result are described for an infrared zoom system with three fields of view. Its zoom ratio is 9, and the corresponding field of view is 3°~27°. The working waveband is from 3μm to 5μm, and its total length is required to be no more than 400mm. The final optical system consists of 9 elements, with two aspheric surfaces and a diffractive optical element. It achieves diffraction-limited imaging at the middle infrared waveband. From the last result we can know using the diffractive optical elements can eliminate the color aberration and helps to reduce the cost of the system; and using the rotated elements in the system it is easy to change the field-of-view and satisfied the cooled detector requirements.

Compressed infrared mirror-lens system design

In the special optical system such as the infrared optical system, the compressed construction and mini module is necessary. In this paper, a kind of compressed infrared lens design is proposed. The total length and focus length ratio is no more than 0.6 and this type system is accessible of temperature, the key step in this design is how to make the system actable. The parasitic light is also analyzed. The couple efficient of cool stop is 100%.

A new kind of three anastigmatic mirrors system

This paper describes the results of the design effort for a new kind of three-mirror anastigmatic system (TMAS) and its tolerance exercise. The system’s focal length is 100mm and the relative aperture is f/10, its total length is nearly f’/3~f’/3.5 and field of view (FOV) is 10° x 1°. The final optical system is a three-mirror unobscured telescope. It achieves diffraction-limited imagery at visible wavelengths. Finally, we can draw two conclusions: 1) design of unobscured optical system is still best approached using fundamental optical design principle; 2) time spent in careful modeling of fabrication, testing will result in more relaxed tolerances and a higher probability of success for the assembled system.

Illumination system design applied to LC rear projective TV system

Based on analyzing the LC rear projective TV system, a fly-eyes lens array telecentric illumination system has been designed, which can magnificently improve the optical performance. The modeling result by means of the LightTools software shows that the uniformity can reach (+4.8%, -6.0%). And the effective energy can be above 91%. At the same time this paper also explicates the method of coupling of illumination system and projection lens system.