Over the past four decades, the evolution of optical technologies has advanced due to one huge development – optical engineering. From operational instruments to lens design, optical engineering focuses on the fabrication of optical components, assembly and alignment techniques, metrology and calibration, and the alignment with other engineering disciplines like thermal, electronic, software, and mechanical.
If you’re wondering about optical engineering or lens design (optical design), learn more about the field of optics and how it connects to the other areas of the field.
Optics and Optical Engineering
Optics is a branch of physics that studies sight and the behavior of light or the properties of transmission and deflection of other forms of radiation.[1]
Photons, or particles representing a quantum of light or other electromagnetic radiation, can behave like a wave or as particles. Though this isn’t fully understood, it provides practical value to optical engineers to calculate quantum effects in lasers, sensors, or other optical technologies. Typically, wave optics are used.
Much of optical design is based on rays – geometrical optics.[2] Instead of thinking about waves in space, we can think of lines that are normal to the waves, or light rays. The behavior can be modeled in simple equations, making rays valuable for optics.
Optical engineering uses the science of optics to design and build devices that direct light for a specific use. They must understand and apply the science of optics to thoroughly understand the capabilities and limitations of a design, including the technology, materials, costs, and tools available.
Lenses and Lens Designers
Simply put, a lens is a curved piece of clear glass or plastic. This is commonly seen in eyeglasses or contact lenses. But for lens designers, a lens is a system that collects and distributes light in a specific manner.
For example, a camera lens isn’t a single lens at all but a collection of lens layers of different shapes and sizes. These are known as lens elements in an optical system.[3] In this context, it’s more accurate to call a lens designer an optical designer.
An optical system can contain various lens elements, including prisms, mirrors, polygon scanners, diffraction gratings, filters, and holographic elements. The designer has a lot to consider, including the light source used with the optical system and the detectors.
Some examples of optical systems design include:
- Camera lenses of all types
- Slide, movie, overhead, and video projectors
- Microscopes, telescopes, and binoculars
- Endoscopes for surgery
- Laser-based optical readers
- Laser printers, office copiers, fax machines, microfilm readers
- Product code laser scanners in supermarkets
- Ultra-precise projector lenses used in integrated circuits
The Process of Optical Design
The typical steps in optical design include:
- Defining the problem: This defines the requirements and limitations of the design problem and the desired performance. The requirements may occasionally contradict each other, forcing a compromise in how the design is approached.
- Pre-design: Once the basic design is determined, the designer must decide on details like the number of elements, size, and more. This involves paper and pencil sketching and graphic software tools.
- Starting point selection: This is the phase when the concept gives way to reality. Designers can use previous works or existing designs to find the starting point for the design.
- Initial analysis: The baseline analysis of the starting point helps designers gauge the improvement versus the spec. Aberration analysis may or may not be part of the process, but it’s useful for selecting variables.
- Optimization: Once the variables are set, such as the thickness, curvature, and index of refraction, a software program is then used to try to improve performance. The constraints and an error function are also defined for optimization. Numerical methods are used to alter the variables systematically to minimize the error and stay within constraints.
- Final analysis: After the lens is optimized, the designer must check that it has the capabilities of the original spec. If it’s not, there may be more optimization.
- Fabrication: Once the optical system is fully optimized to its requirements, it’s prepared for fabrication.
Optical System Optimization
The previous process is a mere introduction to everything that goes into optical design. Optimization is an important aspect of the process since it takes the starting lens and adjusts parameters until it reaches optimal performance.
Optics is about precision. The designer is essential in identifying problems and priorities in the design to ensure that the components themselves are functional and the larger system design. The best designs come from a full understanding of the problem and the physical and technological principles that govern a successful solution.
Optical Engineering or Lens Design at Apollo Optical Systems
If you need help with optical engineering or lens design for your custom optics project, Apollo Optical Systems offers optical and mechanical design for an integrated solution to your problem. Contact us today to discuss your custom optical components and assemblies.
Sources:
[1] https://www.britannica.com/science/optics [2] https://www.sciencedirect.com/topics/physics-and-astronomy/geometrical-optics [3] https://www.britannica.com/technology/optical-system
