JML spherical/flat glass

Spherical and plano lenses are widely used in a huge variety of optical applications. Lenses are often categorized by the curvature of the optical surfaces. Accordingly, spherical lenses are defined by their spherical surfaces which have a constant radius of curvature over the clear aperture. Plano lenses are flat rather than curved. A spherical lens can focus light, either converging or diverging it depending on whether it is a convex or concave curve, respectively. Plano surfaces refract light but do not focus it. In many cases, both types of lenses are used in tandem to achieve the desired effect.

Spherical and plano lenses have been used for centuries, which is a main reason that so many applications use these lens types. Designers also like to incorporate spherical and plano lenses because they are less expensive to make, all else held equal, than shapes such as aspherical and cylindrical. 

Lens Categories by Surface Shape

Lenses can have different shapes on each side. Common shapes include:


Plano-convex lenses have one flat side and one convex side. Plano-convex lenses are often used as stand-alone, single components to focus parallel rays of light (such as a laser beam)  into a single point. They can also collect and collimate light coming from a single-point source.


Plano-concave lenses have one flat side and one concave side. Acting conversely to plano-convex lenses, plano-concave lenses cause a beam of light to diverge. Plano-concave lenses are often used to reduce aberrations caused by other lenses in a group of elements working together to produce a sharp image.


Bi-convex lenses have two convex spherical surfaces. This makes them thicker in the middle and thinner at the edges. Bi-convex lenses are primarily used in two ways. First, if the resolution requirements are modest, a bi-convex lens can be used alone to collect light from a single point on an object and focus it to a single point in the image, with both object and image being a finite distance from the lens. Second, bi-convex lenses are used to add focusing power in a group of elements working together to produce a sharp image


Bi-concave lenses have two concave spherical surfaces, meaning they have thinner middles and thicker edges. They are most often used in conjunction with other lenses to improve imaging performance by reducing chromatic aberration and other aberrations..


Meniscus lenses have one concave side and one convex side. When looking at them from the side, they appear curved or bent. Whether the lens is overall positive or negative in power depends on the relative optical power of the two sides. Meniscus lenses are used to control aberrations and adjust the focal length in conjunction with lenses of other types.

Applications and Industries

Spherical and plano lenses are beneficial across a range of imaging applications, allowing scientists, engineers, and researchers to make precise measurements. Some of the most common applications for these lenses include:

  • Fluorescence Microscope Platforms: Microscope applications use a variety of lenses to examine and identify cross-sections of specimens. Specific applications include cell and tissue sample imaging.
  • Cameras & Laser-based Ophthalmic Tools: Cameras also make use of different lenses to achieve high-quality imaging. Ophthalmic tools for eye testing do this, as well, with different lenses used to diagnose eye disease.
  • Semiconductor Wafer Inspection Tools: Chip engineers use these lenses to identify defects in semiconductor wafers.
  • Industrial Laser Machine Tools: Manufacturing companies use lenses to perform quality control processes throughout the entire manufacturing cycle.
  • Night Vision Optics: These lenses focus and amplify available ambient light in dark areas for mission-critical military operations.

Why Choose JML?

JML Optical specializes in the design and manufacture of spherical and plano lenses for demanding applications. Having been in operation for over 40 years, our team has become experts in crafting high-quality custom lenses for our customers. We can also provide design assistance, lens assembly optimization, manufacturability assistance, and design performance testing.

Contact us today to learn more about our products and our custom solutions.

Spherical Optics

  • Sizes: 4mm-500mm
  • Material Types: all the optical glass, fused silica, and Zerodur™
Parameter Industry Precision Tolerance JML Precision
Index of Refraction (%) +/-0.0005 Melt Controlled
Diameter (mm) +0.00/0.025 +/-0.013
Center Thickness (mm) +/- 0.05 +/-0.025
Power-Irregularity (fringes) 3-1/2 2-1/5
Centration (Total Included Angle in ARC minutes) 1 0.5
Scratch-Dig 40-20 10-5

Plano and Flat Optics

  • Sizes: 4mm-500mm
  • Material: Material Types: all the optical glass, fused silica, and Zerodur™
Parameter Industry Precision Tolerance JML Precision
Index of Refraction (%) +/-0.0005 Melt Controlled
Diameter (mm) +0.00/-0.025 rounds
+/-0.10 squares
Thickness (mm) +/-0.05 +/-0.025
Flatness (waves) 1/10 1/20
Scratch-Dig 40-20 10-5
Parallelism (Arc Minutes) 0.5 0.05
Angular (Arc Minutes) 1 0.025