Optical engineering is the field of study that focuses on applications of optics. Optical engineers design components of optical instruments such as lenses, microscopes, telescopes, and other equipment that utilizes the properties of light. Other devices include optical sensors and measurement systems, lasers, fiber optic communication systems, optical disc systems (e.g. CD, DVD), etc.
Because optical engineers want to design and build devices that make light do something useful, they must understand and apply the science of optics in substantial detail, in order to know what is physically possible to achieve (physics and chemistry). However, they also must know what is practical in terms of available technology, materials, costs, design methods, etc. As with other fields of engineering, computersare important to many (perhaps most) optical engineers. They are used with instruments, for simulation, in design, and for many other applications. Engineers often use general computer tools such asspreadsheets and programming languages, and they make frequent use of specialized optical software designed specifically for their field.
Optical engineering metrology uses optical methods to measure micro-vibrations with instruments like the laser speckle interferometer or to measure the properties of the various masses with instruments measuring refraction.
See also
Optical lens design
Optician
Optical physics
SPIE
Code V
Zemax
HEXAGON (optical software)
The Hughes Executable Application for General-Purpose Optical Analysis (HEXAGON) is an in-house optical engineering software program developed by Hughes Aircraft Company to allow them to design and analyze a wide variety of optical lens systems. There is an extensive interface capability with other optical design programs (CodeV, Zemax, and OSLO); with mechanical CAD programs (Pro/Engineer, AutoCAD, and I-DEAS); and the structural CAD program Nastran. Data can be easily exported to and imported from MATLAB and Excel. Graphical output can be vector graphics, viewed with a built-in viewer or output to WMF format for inclusion in Word or PowerPoint, or bit-map graphics (BMP) image files.
Input is entirely command driven, allowing unattended batch operation; a built-in Macro programming language allows the construction of a simple new 'command' that can execute other commands in a complex manner. Users store their own previously written macros in a macro libraries (a single disk file), and there is an extensive 'permanent' macro library available for all users. The diagram below shows some of the features of the HEXAGON software:
In the 1970s Hughes Aircraft Company acquired the software code ACCOS-V and extensively upgraded it while maintaining the command structure: entry consists of a command word (case insensitive) up to six letters long, followed by an optional qualifier word up to eight letters long, then either a text field or a numeric field containing up to five numbers. The new code was named HEXAGON and many optical designers used interactive terminals to run the program on an IBM 4341 mainframe computer. In the 1980s the program expanded its capabilities in optimization, tolerance analysis, and physical optics; this later capability is a subset of HEXAGON named SOQ, for System Optical Quality, that models coherent laser systems using a two-dimensional complex field array. In the 1985 Hughes was sold to General Motors and renamed GMH; in the 1997 GMH was acquired by Raytheon Company. Currently Raytheon has exclusive use of the proprietary software code. The acronym HEXAGON is now said to stand for "Handy EXpert Application for General-Purpose Optical Analysis".
Оптическая разработка - область исследования, которое сосредотачивается на применениях оптики. Оптические инженеры проектируют компоненты оптических инструментов, такие как линзы, микроскопы, телескопы, и другое оборудование, которое использует свойства света. Другие устройства включают оптические датчики и системы измерения, лазеры, волокно оптические системы связи, оптические системы диска (например, Компакт-диск, DVD), и т.д. Поскольку оптические инженеры хотят проектировать и построить устройства, которые заставляют свет сделать что-то полезное, они должны понять и применить науку об оптике в существенных деталях, чтобы знать того, чего физически возможно достигнуть (физика и химия). Однако, они также должны знать то, что практично с точки зрения доступной технологии, материалов, затрат, методов дизайна, и т.д. Как с другими областями разработки, computersare важный для многих (возможно, больше всего) оптические инженеры. Они используются с инструментами, для моделирования, в дизайне, и для многих других заявлений. Инженеры часто используют общие компьютерные инструменты такой asspreadsheets и языки программирования, и они делают частое использование специализированного оптического программного обеспечения специально разработанным для их области. Оптическая техническая метрология использует оптические методы, чтобы измерить микроколебания с инструментами как лазерный интерферометр веснушки или измерить свойства различных масс с инструментами, измеряющими преломление.
Оптическая инженерия области исследования, которое фокусируется на приложенияхоптики. Оптические компоненты инженеров-конструкторов оптических приборов, таких как линзы, микроскопы, телескопы и другое оборудование, которое использует свойства света. Другие устройства включают в себя оптические датчики и измерительные системы, лазеры, волоконно-оптических систем связи, оптические системы диска (например, CD, DVD) и др. Поскольку оптические инженеры хотят проектировать и строить устройства, которые делают легкий сделать что-то полезное, они должны понимать и применять оптику к существенным деталям, для того, чтобы знать, что физически возможно достичь (физика и химия). Однако, они также должны знать, что практическое с точки зрения имеющихсятехнологий, материалов, затрат, методы проектирования и т.д. Как и в других областях техники, computersare важно для многих (возможно, большинство) оптических инженеров.Они используются с инструментами, для моделирования, проектирования, и для многихдругих приложений. Инженеры часто используют инструменты общего компьютера, такихasspreadsheets и языков программирования, и они делают частое использованиеспециализированных оптических программное обеспечение, предназначенноеспециально для своей области. Оптическая метрология инженерных использует оптические методы измерениямикро-вибрации с инструменты, такие как лазерная спекл-интерферометр для измеренияили свойства различных масс с инструментами измерения рефракции.
Optical lens design
Optical lens design refers to the calculation of lens construction parameters (variables) that will meet a set of performance requirements and constraints, including cost and schedule limitations.
Construction parameters include surface profile types (spherical, aspheric, holographic, diffractive, etc.), and the parameters for each surface type such as radius of curvature, distance to the next surface, glass type and optionally tilt and decenter.
Design requirements
Performance requirements can include:
Optical performance, i.e., image quality: quantified by encircled energy, modulation transfer function, Strehl ratio, ghost reflection control, and pupil performance (size, location and aberration control); the choice of the image quality metric is application specific.
Physical requirements such as weight, static volume, dynamic volume, center of gravity and overall configuration requirements.
Environmental requirements: ranges for temperature, pressure, vibration and electromagnetic shielding.
Design constraints can include realistic lens element center and edge thicknesses, minimum and maximum air-spaces between lenses, maximum constraints on entrance and exit angles, physically realizable glass index of refraction and dispersion properties.
Manufacturing costs and delivery schedules are also a major part of optical design. The price of an optical glass blank of given dimensions can vary by a factor of fifty or more, depending on the size, glass type, index homogeneity quality, and availability, with BK7 usually being the cheapest. Costs for larger and/or thicker optical blanks of a given material, above 100mm to 150mm or so, usually increase faster than what would be proportional to just the increase in physical volume. This is primarily due to increased blank annealing time required to achieve acceptable index homogeneity and internal stress birefringence levels throughout the blank volume. Availability of glass blanks is driven by how frequently a particular glass type is mixed and poured by a given manufacturer, and can seriously affect manufacturing cost and schedule.
Process
Lenses can first be designed using paraxial theory to position images and pupils, then real surfaces inserted and optimized. Paraxial theory can be skipped in simpler cases and the lens directly optimized using real surfaces. Lenses are first designed using average index of refraction and dispersion (see Abbe number) properties published in the glass manufacturer's catalog and though glass model calculations. However, the properties of the real glass blanks will vary from this ideal; index of refraction values can vary by as much as 0.0003 or more from catalog values, and dispersion can either remain about the same or vary slightly. These changes in index and dispersion can sometimes be enough to affect the lens focus location and imaging performance in highly corrected systems.
The lens blank manufacturing process is as follows:
The glass batch ingredients for a desired glass type are mixed together in a powder state,
the powder mixture is melted together in a furnace,
the fluid is further mixed while molten to maximize batch homogeneity,
poured into lens blanks and
annealed according to empirically determined time-temperature schedules.
The glass blank pedigree, or "melt data", can be determined for a given glass batch by making small precision prisms from various locations in the batch and measuring their index of refraction on a spectrometer, typically at five or more wavelengths. Lens design programs have curve fitting routines that can fit the melt data to a selected dispersion curve, from which the index of refraction at any wavelength within the fitted wavelength range can be calculated. A re-optimization, or "melt re-comp", can then be performed on the lens design using measured index of refraction data where available. When manufactured, the resulting lens performance will more closely match the desired requirements than if average glass catalog values for index of refraction were assumed.
Delivery schedules are impacted by glass and mirror blank availability and lead times to acquire, the amount of tooling a shop must fabricate prior to starting on a project, the manufacturing tolerances on the parts (tighter tolerances mean longer fab times), the complexity of any optical coatings that must be applied to the finished parts, further complexities in mounting or bonding lens elements into cells and in the overall lens system assembly, and any post-assembly alignment and quality control testing and tooling required. Tooling costs and delivery schedules can be reduced by using existing tooling at any given shop wherever possible, and by maximizing manufacturing tolerances to the extent possible.