Simple Graphical Selection of Optical Materials for an Athermal and Achromatic Design Using Equivalent Abbe Number and Thermal Glass Constant

This paper presents a new graphical method for selecting a pair of optical glasses to simultaneouslyachromatize and athermalize an imaging lens made of materials in contact. An athermal glass map thatplots thermal glass constant versus inverse Abbe number is derived through analysis of optical glassesand plastic materials in visible light. By introducing the equivalent Abbe number and equivalent thermalglass constant, although it is a multi-lens system, we have a simple way to visually identify possible opticalmaterials. Applying this method to design a phone camera lens equipped with quarter inch image sensorhaving 8-mega pixels, the thermal defocuses over -20°C to +60°C are reduced to be much less than thedepth of focus of the system KCI Citation Count: 6