Plano-Convex Lenses

N-BK7, UV grade fused silica, CaF₂, Ge, ZnSe

Surface Flatness:

Single Layer MgF₂
AR/AR@250-400nm, Ravg<0.5%
AR/AR@400-700nm, Ravg<0.5%
AR/AR@650-1050nm, Ravg<0.5%
AR/AR@1000-1650nm, Ravg<0.5%

Surface Quality:

Clear Aperture:


wdt_ID Attributes Values
Plano-Convex lenses are the best choice for focusing parallel rays of light to a single point. They can be used to focus, collect and collimate light.
Planoconvex lenses are positive focal length elements that have one spherical surface and one flat surface. These lenses are designed for infinite conjugate (parallel light) use or simple imaging in non-critical applications. These optic lenses are ideal for all-purpose focusing elements.
A plano-convex lens has one flat side and one side which curves outward. When parallel beams of light pass through this lens, they converge on a single point regardless of where they enter the lens. Such lenses are commonly used in
  • magnifying glasses
  • telescopes
  • microscopes
  • and binoculars
  • and so on…
When used to make images, these lenses produce real inverted images, i.e. if the image were projected onto a flat surface the image would be inverted with respect to both axes.

Related Resource for reference

As the most common type of lens element, a plano-convex lens is a convergent lens with one flat surface and one convex surface that allow for light to be focused, collected and collimated. More specifically, the two surfaces of a plano-convex lense function together by focusing parallel light rays to a positive focal point. In doing so, the plano-convex lens forms real images that can be easily manipulated through the use of spatial filters. The asymmetry of plano-convex lenses reduces spherical aberration in applications where the image and object lie at unequal distances from the lens. The curved surface of a plano-convex lens has a focusing effect on light-rays, while the plane surface does not have a focusing or de-focusing effect. Some common applications for plano-convex lenses include light collimation or monochromatic processes that are required in pharmaceutical, industrial, robotics or defense sects.
To further enhance the capabilities of plano-convex lenses, antireflective coatings can be added to meet various optical systems, lasers and assemblies’ requirements. When used to cut steel or other thick materials, plano-convex lenses provide users with a greater cut width, which, as a result, supports the ability of the laser’s oxygen to enter the material and assist in the cutting rocess. Furthermore, when used for these cutting applications, plano-convex lenses have also been shown to provide a greater depth of field that is required to maintain a taperless edge.
The maximum sharp focus is achieved when the curved portion of the lens is oriented toward the object. Plano-convex lenses are used for applying focus to an optical system, and collimating diverging light beams. Plano-convex lenses have both positive focal lengths and an orientation that plays a crucial role in determining image quality. Low spherical aberration is obtained if the lens is orientated in a way that causes the collimated beam to enter or exit the curved surface, thereby making the plano side face towards the point source or focus.
A lens curved on one side and flat on the other. The more pronounced the curvature of the convex side, the closer to the lens will be the point at which light rays entering the lens from the convex side will converge. The distance from the lens to this point is called the focal length.
A plano-convex lens is described by its diameter and focal length. For example, a 6″x9″ lens will have a diameter of 6″ and a 9″ focal length. The shorter the focal length, relative to the diameter of the lens, the wider the beam of light; thus, a 6″x12″ lens will emit a beam of light 3/4 the width of the 6″x9″ lens. When two plano-convex lenses are used “belly-to-belly”, their effective combined focal length is halved. For example, two 6″x9″ lenses belly-to-belly will have an effective focal length of 4½”.
Fixtures using plano-convex lenses typically project sharp-edged images.

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The focal length of a plano convex lens is ‘f’ and its refractive index is 1.5. It is kept over a plane glass plate with its curved surface touching the glass plate. The gap between the lens and the glass plate is filled by a liquid. As a result, the effective focal length of the combination becomes 2f. Then the refractive index of the liquid is 1.25
From lens maker’s formula:-
For, plano-convex lens:-
Now, we can treat the fluid below the plano-convex lens as a plano -concave lens of refractive index μ and focal length f′
So,  f′1​=(μ−1)(−R1​−∞1​)
Now, for combination:-
Types of magnifiers
There are several types of magnifiers available. The choice of an optical design for a magnifier depends upon the required power and the intended application of the magnifier.
For low powers, about 2–10×, a simple double convex lens is applicable. (Early simple microscopes such as Leeuwenhoek’s magnified up to 300×.) The image can be improved if the lens has specific aspheric surfaces, as can be easily obtained in a plastic molded lens. A reduction of distortion is noted when an aspheric lens is used, and the manufacture of such low-power aspheric plastic magnifiers is a major industry. For higher powers of 10–50×, there are a number of forms for magnifiers in which the simple magnifier is replaced by a compound lens made up of several lenses mounted together.
A direct improvement in the distortion that may be expected from a magnifier can be obtained by the use of two simple lenses, usually plano-convex (flat on one side, outward-curved on the other, with the curved surfaces facing each other). This type of magnifier is based upon the eyepiece of the Huygenian telescope, in which the lateral chromatic aberration is corrected by spacing the elements a focal length apart. Since the imaging properties are provided and shared by two components, the spherical aberration and the distortion of the magnifier are greatly reduced over those of a simple lens of the same power.
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