Optical systems are integral components of many products and processes, from cameras and movie projectors to endoscopes and microscopes. The process of developing one that fully meets the requirements and restrictions of the application is known as optical system design. It can involve many stages, each of which must be carefully conducted to ensure the final solution functions and performs as intended.
What Is Optical System Design?
Optical system design is the process by which optical engineers determine everything they need to know to develop an optical system that is appropriate for the intended use, such as the structural requirements and performance parameters. The end result is a system design that will exhibit the optical characteristics demanded by the customer. It can be used to create prototypes for testing and, if approved, production units.
The optical system design process has many stages, including the following:
- Conducting first-order calculations. These calculations are used to determine the basic optical properties the system needs to meet the technical requirements and restrictions, such as focal length, lineal field/field angle, numerical/relative aperture, and conjugate distance. While these dimensions are calculated according to first-order optical system theory and formulas, real-life mechanical and electrical system limitations must also be considered.
- Choosing the design form. Once these calculations have been made, the design engineering team can choose an initial structure (i.e., design form) that meets the technical requirements and restrictions. This structure is chosen from existing solutions for similar applications. It serves as a starting point for the final design.
- Optimizing the design. After the initial structure has been chosen, it is analyzed and evaluated to see if and how it could be improved to better suit the application. An optical calculation program can be used to calculate the optical path and aberration curves. Any issues that are discovered can then be corrected until the system design meets the image quality requirements.
- Evaluating image quality. The quality of image outputted by an optical system is influenced by the size of aberration present in the design. While the optimization process can manage some of the aberrations, it cannot adjust all of them to zero. The system designers and engineers need to understand the system’s tolerance for residual aberration to appropriately judge whether or not its image quality is good or bad.
Optical System Design Considerations
Engineers must consider many elements when working on an optical system design. Some of the key factors to keep in mind are:
- F-number. This specification is the ratio of the system’s focal length to its aperture diameter. It affects the system’s ability to pass through light.
- Focal length. This specification is the distance at which incoming collimated light rays converge to a single point on the optical axis. Longer focal lengths mean a narrower angle of view and higher magnification. Shorter focal lengths mean a wider angle of view and lower magnification.
- System dimensions. These specifications refer to the horizontal and vertical dimensions of the system.
- Imaging quality. This specification refers to the accuracy of the images presented in the system’s field of view. Some systems may only need good image quality in certain areas of the field of view (e.g., microscopes and telescopes need high image quality in the central field of view), while others need good image quality across the whole field of view (e.g., cameras).
Beyond the optical characteristics of the system, engineers must also focus on its structure. It must be designed and built to suit the environment in which it will be used. For example, if it will be subjected to high temperatures, vibrations, or shock, it must be durable.
Contact the Optical System Design Experts at JML Optical Today
Want to learn more about the optical system design process? Ask the experts at JML Optical. Equipped with extensive experience engineering solutions for optical and optomechanical challenges, we can answer and address any questions or concerns you may have. To learn more about our design engineering capabilities, check out our capabilities page. To discuss your optical system needs with one of our team members, request a quote.