From small to our hands a mobile phone, to the daily life of TV, computers, and then to the military industry in the field of national defense, aerospace, optical glass demand with the development of modern science and technology and increasingly extensive
More and more precision instruments are used in the new technology of the combination of optomechanics, which promotes the increasingly strict requirements of multi-function, high performance and low cost, and promotes the development of traditional optical glass processing equipment, production technology and processing technology. This change has pushed the development of optical mechanics technology in two different directions.
First, to the small, light and cheap efficient processing direction. With the rapid development of optical plastics and glass die-casting technology, the cost of aspherical lenses has been greatly reduced, and the supply has been greatly increased, and more and more various optical systems have begun to adopt. For example, very thin zoom lenses are widely used in mobile phones. It is precisely because of the continuous expansion of the application of these small, lightweight and cheap optical glasses in various fields, which has led to the rapid development of optical efficient processing technology.
Second, to the direction of ultra-precision machining. The technological progress in the field of advanced science and technology, especially in the national defense industry, has put forward new requirements for ultra-precision optical glass. For example, the optical system of manned spaceflight, laser weapons, optical fiber communication components, and micro-optical glass in optical integrated circuits are ultra-precision optical glasses. The processing accuracy of these optical glasses even reaches the nanometer level. The processing of these parts cannot be achieved by traditional methods, and must be achieved by optical glass processing equipment and ultra-precision processing technology.
The traditional optical glass processing method has a history of more than 100 years, which can be popularly understood as "a handful of sand and a handful of water". The new optical glass processing method began in the 1970s, the military optical system expanded from white light to infrared and laser systems, and the optical glass also put forward the difficult requirements of good imaging quality, small volume, light weight, and simple structure. Subsequently, the optical processing industry has carried out large-scale technological revolution and innovation activities, and new optical glass processing methods continue to emerge. At present, the most commonly used optical glass processing technologies are: CNC single point diamond processing technology, CNC grinding and polishing technology, optical lens molding technology, optical plastic molding technology, magnetorheological polishing technology, electroforming technology and traditional grinding and polishing technology.
Second, the basic principle of ultra-precision machining technology
1, CNC single point diamond processing technology
Numerical control single point diamond processing technology is an aspherical optical glass processing technology. It is in the ultra-precision CNC lathe, the use of natural single crystal diamond tool, under the specific processing environment precise control conditions, the use of diamond tool single point turning to process aspherical optical glass. The technology is mainly used for optical glass of medium and small size infrared crystals and metal materials.
2, CNC grinding and polishing technology
CNC grinding and polishing technology is an optical glass manufacturing technology that is made of CNC precision machine tools that grind the surface of the workpiece into the required surface shape, and then polished by a flexible polishing die to make the workpiece meet the technical requirements. The principle of this technology is closest to the classical optical processing technology, mainly through the digital precision control of the machine tool to achieve the precision processing of optical glass.
3, optical lens molding technology
The optical lens molding technology is to put the softened glass into a high-precision mold, and directly mold the optical glass to meet the requirements of use under the conditions of heating and pressure and no oxygen. It can be said that the widespread application of optical lens molding technology is a major revolution in optical glass parts processing technology. This technology has epoch-making significance for the cost reduction and production increase of aspherical glass parts.
Third, the application range of optical glass ultra-precision processing technology
1, CNC single point diamond processing technology
At present, the diamond turning technology can be directly processed to meet the optical surface quality requirements of the materials are mainly non-ferrous metals, errors, plastics and infrared optical crystals, and the processing of glass can not meet the optical surface quality requirements, need to continue grinding and polishing correction. Another major use of CNC single point diamond processing technology is the processing of various precision molds required for die molding.
2, CNC grinding and polishing technology
The main processing material of CNC grinding and polishing technology is glass, which makes up for the shortage of CNC single point diamond processing technology that can not directly process finished optical glass parts. This technology is mainly used for processing spherical and aspherical optical glass, which is the main technology to replace the traditional classical optical glass processing method, and has the advantages of high precision and high processing efficiency. At present, the development history of the technology in the market is relatively long, mature equipment is more comprehensive, such as Germany Satisloh company, Optotech company and Schneider company launched different types of matte grinding and polishing machine tools, China has also carried out a large number of numerical control technology research.
CNC grinding and polishing technology has not only made great progress in CNC equipment automation and machining accuracy, but also greatly promoted the development of optical aspherical surface machining technology by studying various polishing methods and principles.
3, optical lens molding technology
At present, optical lens molding technology has been used to mass produce precision spherical and aspherical lenses. It can not only manufacture commonly used medium aperture lenses, but also extend to 100 micron micro lens arrays and 50 mm larger aperture lenses, not only can manufacture spherical and aspherical optical glass in military and civilian optical instruments, but also can manufacture aspherical lenses for optical communication fiber couplers.
Now, this advanced glass optical glass manufacturing technology is also mastered in the United States Corning, Rochester Precision Optics (RPO), Maxell, Japan's OHARA (Kohara), H0YA (Hoya), Olympus, Panasonic, Germany's Zeiss, Bluebell Industries of Britain and Philips of the Netherlands are among a handful of foreign companies.
Fourth, optical glass ultra-precision processing technology progress at home and abroad
1, the status quo of ultra-precision machining technology of foreign aspherical parts
In the world, optical processing has developed to the fifth generation of CNC machining technology, which has reached high precision, high speed, high efficiency and specialization, and can complete the processing of high-precision aspherical parts, among which the more prominent is the German optical processing technology. Their CNC machining technology not only covers from the plane, prism, spherical to aspherical surface shape of various grinding, polishing technology, as well as supporting high-precision detection technology, processing size and detection range from 0>1 ~ 800mm "in the aspherical processing is particularly prominent, the use of advanced technology can easily complete the processing of high-precision aspherical surface. Some of the machining methods of aspherical surface use the outer edge of the grinding wheel point contact matte grinding, some use the elastic film polishing and small grinding head correction polishing way; The clamping methods of the workpiece include hydraulic pressure and vacuum adsorption.
2, the status quo of ultra-precision machining technology of aspherical parts in China
The research of ultra-precision machining technology in China began in the early 1980s, and there is a gap of more than 20 years with foreign countries. China's military photoelectric enterprises in the optical glass processing technology after years of development, aspheric CNC processing technology in recent years has also been greatly developed, especially the aerospace system should introduce some advanced technology and equipment, the technical level of some enterprises has been greatly improved, but the weapons industry photoelectric enterprises optical processing generally still use the traditional process, Most of the processing of aspherical surface is by hand grinding, the efficiency is very low, the manual repair process is also prone to error, poor reliability. Optical glass lens molding also only stays in the blank stage. With the increasing demand for large aperture and high precision aspherical mirror in modern weapons equipment, the improvement of aspherical processing technology is urgent. However, due to the high price of imported aspherical CNC machining equipment, most companies are only equipped with a small amount of equipment, which can only solve the aspherical processing of existing high-end products. It is difficult to form a batch and put forward a new process on this basis.
V. Concluding remarks
At present, the development history of new optical systems has been more than 30 years in China and developed countries, and new optical systems, especially high-order aspherical optical systems, have obtained considerable development and utilization. In this field, there is still a considerable gap, or even a blank. This situation has seriously hindered the development of high-performance optical systems in our country and affected the equipment level of our army. It is of great significance to carry out the research on application foundation, key technology, system and engineering technology. The development of ultra-precision machining technology has revolutionized the design and manufacture of modern optical systems, changing the situation that the conceptual design of optical systems has been stagnant for hundreds of years. It is of great significance to solve the bottleneck technology in the manufacturing of modern optical systems in China, especially in the processing of high-resolution, large-aperture and high-order aspherical optical systems, to reach and break through the actual level of high-resolution large-aperture optical systems in the world, and to achieve a new level of advanced optical manufacturing technology in China.