How to Make a Convex Lens

Making a lens takes training and expertise. The Ohio State University Medical Center (OSU) notes that convex lenses are used in glasses to correct hyperopia, also referred to as farsighted vision. Convex lenses are thicker in the middle than at the edges and are made the same way as other spectacle lenses. The process of making a lens is called grinding or surfacing. You need a piece of optical glass or plastic called a lens blank and special optical equipment to make a convex lens.

Things You'll Need

• Lens surfacing machine
• Blocking machine
• Lens blank

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Instructions

• 1

  Put protective film on the lens blank to keep it from being scratched during the grinding process. The film is a special, thin piece of adhesive that keeps the lens in place on the lens block, a piece that holds the lens in place inside the surfacing machine.

• 2

  Use melted lead or a special metal alloy to attach the block to the lens over the film. This is called "blocking," according to Opticianworks.com. Blocking takes a metal form and glues it to the back of the lens. The lead or alloy sticks the metal form to the lens. Blocking is done in a special machine.

• 3

  Set the number on the machine to the corresponding desired magnification power of the convex lens. Lens power is also called diopter, according to All About Vision. Diopter increases in 0.25 increments. Refer to the surfacing machine's manual if you are unsure how to set the power because different machines have unique settings.

• 4

  Put the uncut lens blank into the chuck of the surfacing machine. The block you attached to the lens holds the lens in place while the machine grinds the lens into the proper convex power. Close the door. Start the machine.

• 5

  Take the lens out after the machine has completely stopped, usually after about 30 seconds to one minute, depending on the machine. Remove the lens from the chuck and carefully peel off the adhesive film.