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Precision Optics - Profiting in the Next Millennium
Harvey M. Pollicove
Center for Optics Manufacturing
University of Rochester
Rochester, NY
Optical shops located in countries with newly developing economies generally begin to compete in the world market by entering the low-skill, high-volume end of the optics market. While these new competitors have an abundance of low-skill labor and the advantage of low labor costs, they can rarely afford to make a major capital investment to enter the market. Having only limited capabilities and resources, the ambitious entrants use their low operating costs to aggressively compete for customers that are purchasing basic optics. As a result, the selling price of low-skill, high-volume basic optics is continuously decreasing.
Higher Performance Demands
| At the other end of the market are the high-value precision optics that enable technology-driven and special-use products. These products typically maintain their value until replaced by a newer technology. Other than the pricing adjustments needed to combat inflationary pressures, OEM price reductions are not common until a new replacement technology is fully developed and demonstrated to be more effective. Component selling prices and profit margins are reasonably maintained throughout the life cycle. As a general rule, technology-driven products demand higher levels of optical system performance and the components require much better surface figure quality and finish than consumer optics.
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Figure 1: The market for precision optics is rapidly expanding as technology driven applications increase demand.ˇ@ |
As the next Millennium approaches, there is an increasing demand for precision optics suppliers that can keep pace with the rapid expansion of the technology-driven and special-use product markets. Historically, this segment of the optics market was limited, driven mostly by the needs of the military or for scientific research. Precision optical components, and especially aspheres, were only produced by highly-skilled opticians in small optical shops that used in-house developed proprietary processes and equipment. Now, that must change. The availability of highly precise optics is essential to the success of an ever increasing number of new optical product technologies for business, commercial, industrial, medical, and military applications.
The Forecast for Profitability
In the next ten years, the demand for precision optics will grow at a rate faster than at any time in its history. New special-use and technology-driven products in optical communications, metrology, machine vision, miniaturized optoelectromechanical systems, laser materials processing, digital camera lenses, digital projection lenses, medical equipment, computer storage, optics for integrated-circuit fabrication, and other emerging technologies will significantly increase the demand for high quality components.
| Product technology advances will require highly precise spherical optics to improve optical system performance. In addition, there will be a dramatic increase in the demand for aspheres and freeform (no regard for symmetry) optical components that will advance optical system performance and offer innovative packaging possibilities. The shops that can supply highly precise optics at a reasonable cost will profit.
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Figure 2: The benefit of aspheres. Highly precise optical surfaces will be required to meet the technology demands of future business, commercial, industrial, medical and military
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Not only will products based on new optical technologies expand, but both their optical content and component value will increase. The availability of precise optical components, even though they are only a small element of the final system that they enable, is essential to the commercial success of the new Millenniumˇ¦s leading-edge products. As optical system requirements become more stringent, both the number of components and their value increase. For instance, in low to medium volumes, the price of a 0.10 wave spherical optic is 3 to 5 times the cost of a 0.50 wave optic. An asphere might be 10 to 20 times the cost of a spherical optic. In terms of optical content, a DVD optical head has more optical components than a CD audio optical head.
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Figure 3: 1950ˇ¦s optics manufacturing technology (left) is being replaced by state-of-the-art, computer-controlled equipment developed at the Center for Optics Manufacturing (right).
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As product technology advances increase optical component performance requirements, major changes will be necessary in the manufacturing technology used to produce optical components and systems. To compete at the high end, optics shops will have to invest in capital equipment and adopt manufacturing technologies that take advantage of deterministic processes to improve quality. Investments in computer-controlled manufacturing equipment will provide the shop with a broader range of manufacturing capabilities and improve quality, while reducing labor costs. |
Manufacturing processes based on deterministic processes and well-trained operators will make small batch sizes and high quality precision optics affordable. Computer numerically controlled machining centers are a basic necessity in the battle to maximize production flexibility, increase operator productivity, and achieve the consistent perfection required by the quality-conscious buyer of tomorrow. Precision surfaces and non-circular shapes produced using deterministic optics manufacturing techniques and computer-controlled machining centers will be the largest and most profitable growth segment in the optics industry.
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Grinding Out the Future
Traditionally, lenses have had spherical optical surfaces. However, it is well documented that significant design simplifications and improvements in image quality can be obtained by using aspheric surfaces. To be more effective, future high performance imaging systems will require cost-effective aspheric surfaces in low and medium volumes.
The major obstacle to producing aspheres for visible optical systems has been the lack of commercially-available computer-controlled grinding and polishing equipment. The introduction of the University of Rochesterˇ¦s Center for Optics Manufacturingˇ¦s Opticam and deterministic microgrinding (DMG) processes provide optics fabricators with increased capabilities and enabling technologies to replace costly labor and skill-intensive conventional spherical lens production methods. Recently, DMG technology has been extended to develop a new computer-controlled contouring deterministic microgrinder that can produce aspheric optical surface form and figure accuracy in minutes, compared to the conventional grinding techniques that can take weeks. |
Figure 4: The PC-controlled Nanotech™ 150AG is an ultra precision grinding platform designed to deterministically microgrind complex aspheric shapes. |
The Nanotech™ 150AG (built by Moore Nanotechnology Systems in Keene, NH) is a PC controlled, ultra-precision microgrinder and machining system that is capable of generating axisymmetric aspheric optical surfaces up to 100 mm in diameter. The machineˇ¦s PC-based (Windows NT) controller is programmed by entering the desired aspheric coefficients, the part thickness, and final part diameter into a menu screen table. The two-axis (hydrostatic guideways) microgrinder has two spindles - a precision ball bearing spindle for rough shaping and a separate air bearing spindle for final figuring. The dual-spindle design produces spherical or aspheric surfaces that require little post-polishing.
After microgrinding, an on-machine touch-probe profilometer measures the form generated without removing the part from the chuck. The computer compares the measured surface data to the desired surface input by the operator, if form error correction is necessary a compensated tool path program is automatically generated for the machine to execute. The low subsurface damage and good form control achieved during the deterministic microgrinding process are critical to the successful implementation of magnetorheological finishing (MRF).
Magnetorheological Finishing
The Q22 Magnetorheological Finishing System (from QED Technologies of Rochester, NY) is a revolutionary deterministic polishing machine that replaces the highly-skilled artisanˇ¦s iterative non-deterministic polishing method with highly precise, computer-predicted surface form and figure accuracy. MRF has several advantages that eliminate the problems of classical polishing:
The MRF ˇ§polishing toolˇ¨ is a compliant fluid that adapts to any surface shape.
The interferometrically characterized MRF ˇ§polishing toolˇ¨ never dulls or changes.
MRF removal rates are very high, making processing times short.
MRF is capable of producing spherical and aspheric surfaces that have less than 0.10 wave p-v surface form, less than 10 Å rms surface micro-roughness, and no subsurface damage (SSD). The Q22 can be used for both rapid prototyping and volume production runs. The system may be used to polish ground surfaces to optical finish, or to improve an already-polished optical surface. MRF provides the ability to finalize an optical surface to pristine finish, figure and form, regardless of symmetry, geometry, or slope variation. Process cycle times are short, producing 0.10 wave polished spheres, flats, or aspheres in minutes instead of weeks. |
Figure 5: The Q22 MRF machine is a revolutionary polishing machine that replaces labor and skill intensive pitch polishing methods. |
A Profitable Future
A profitable future will require the ability to make affordable precision optics in any surface shape. The realization of computer-controlled deterministic microgrinding and magnetorheological finishing introduces technology that achieves the need for the cost effective manufacture of highly precise spherical and aspheric components.
Figure 6: Aspheric optics manufacturing using COM-developed technologies. State-of-the-art technologies will enable optics manufacturers to create the precision optical surfaces that ensure a profitable future. |
These new technologies eliminate industryˇ¦s costly dependence on outdated labor-intensive equipment and highly specialized individual skills. Optical shops that adopt these state-of-the-art manufacturing technologies will be in a position to produce the precision that insures a profitable future. |
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Honorary Chairman
Precision Optics
