To design a system using optical components, it is important to understand exactly what each specification means. Please refer to the below data for the production specification and surface of the lens and glass. This technical note has been reorganized based on a common definition of specification used by most optical companies. Understanding the general contents of the lens makes it a little easier to access most optical components. Increasing your productive capabilities and understanding of optics will give you a wider range of system design and operate.
The thickness of the lens center is usually the material thickness of the part measured from the center. The center thickness of the lens can have a significant impact on optical performance, as the thickness of the center determines the path of light through the lens along with the radius of curvature. The thickness tolerance of the ZENOPS is manufactured to ¡¾0.05mm of standard quality and ¡¾0.01mm of high quality.
The diameter tolerance of the lens is the most basic standard for design the lens. Diameter tolerances themselves does not has a significant impact of optical performance, but are very important tolerances when assemble to covers. If the diameter of the lens is different from the tolerance reference, the mechanical axis may change from the optical axis after assembly and may deviate from the center. The typical diameter tolerance of ZENOPS is ¡¾0.05mm for standard quality and ¡¾0.01mm for precision quality.
Centering is defined by Beam deviation ¥ä and can be calculated with a simple formula for wedge angle W. The centering of the lens is defined as the outer circumference of the lens, forming a radius of equal distance anywhere in a straight line from the center reference axis to the outer periphery. The center of the lens represents the physical displacement from the optical axis to the mechanical axis. The optical axis of the lens is defined by the optical surface and refers to a line connecting the curvature of the surface.
Then ¡°W¡± means wedge angle, often expressed as arcminutes, and "n" is index of refraction.
The radius of curvature is defined as the distance between the center of the lens and the center of curvature. The value can be defined as value of ¡¾ depending on whether it is convex lens, plano, or concave. Checking the curvature value allows you to determine the length of the optical path of the laser beam passing through the lens and the refractive power of the surface. The ZENOPS standard product is manufactured with a radius of curvature tolerance of ¡¾0.1mm, but if a high precision lens is required, manufactured with the highest quality of ¡¾0.01mm.
Clear aperture is defined as the diameter or size of an optical component that requires specification. If it is outside the standard, the manufacturer would not guarantee the lens. The clear aperture can be changed according to the customer's request and is set slightly differently depending on the lens.
The corners and edge of the lens are made of glass and are vulnerable to external impact. Therefore, general way to protect edges is to process them at an angle. Bevel is defined as face width, angle. And roles to distribute the impact by forming a constant angle at the corner. The typical forming angle is 45¡Æ and the face width is applied depending on the diameter of the lens. Lenses with a small radius of curvature, such as lenses with a diameter of 0.1 inches or less, or lenses diameter is bigger than 0.85 multiplied by the radius of curvature it does not perform a bevel. Bevel will be added if necessary or customer's request.
Parallelism defines the degree to which two sides are parallel to each other. When a flat surface, such as a window, is an important factor in quality. The distortion is minimized when the surface is flat, and the quality of these products is degraded when not flat. Typical tolerance range is represented and managed in units from 5 arcminutes down to a few arcseconds.
The refraction of a medium is the ratio of the speed of light in vacuum to the speed of light in the medium. The glass for regular visible is in a lower range than the glass optimized for infrared. The refraction of the glass is a very important optical property because the power of the surface can be derived through several factors, such as the difference between the surface curvature radius and the refractive index of the medium on one side of the surface. The inhomogeneity characteristics specified by the glass manufacturer are related to the refractive index deviation of the glass. Inhomogeneity is specified by grade and please refer to the following general refraction tolerance deviation.
The LIDT is a very important parameter for laser systems and applications in optical components. In the laser market defined the LIDT, defined as the output energy of a laser per area that an optical part can endured. Laser systems are laser and optical products interact to reduce the performance of optical parts due to coating and surface material deformation and damage. When designing an laser system, should be enough consideration that it does not more than the specified value of the LIDT.
Surface flatness or surface figure is a standard for surface precision that measures the deviation of optical components. Measurement is using an optical flat mirror which is a comparison criterion for surface precision. Place the plane of the lens under test facing the optical flat to check the flatness of the optical part through the pattern that appears. In general, the flatness of the optical part is measured by the lambda(¥ë) value which is the multiple of the wavelength of the test source. ZENOPS's high-quality standard products are manufactured with a precision of ¥ë/4.
Surface finish also known as surface texture or surface roughness and it can be an important criterion of quality. A smooth surface is usually more durable than a rough surface, and when rough it tends to abrasion faster when a laser beam passes through. Typical Surface finish production tolerances are standardized up to 20Å RMS for standard products and up to 5Å RMS for high quality.