Objective:
Improve brightness and contrast of large-legend keycaps on mechanical keyswitch keyboards.
Method:
Insert PMMA plastic optical fiber segments into keyswitches to
couple light from existing surface mount LEDs up into the keycaps.
Basic Requirements:
Computer keyboard with the following properties -
• ‘Hot Swappable’ (interchangeable) keyswitches
• Surfacemount backlight LEDs on the existing PCB
• Plastic fiberoptic cable
• Simple reaming tools
Basic Procedure:
• Remove a keyswitch
• Ream a round hole into the keyswitch frame
• Insert a pre-defined length of plastic optical fiber
• Reinstall the keyswitch
Anticipated Materials Cost:
• About 5 Dollars US total for a full-size 104 key keyboard
(approximately 5 cents per key)
Keyswitch Backlight Modification Using Optical Fiber
© Daniel Baran 2025-2026
Keyswitch modified with
circular opening for fiber.
circular opening for fiber.
Keyswitch with inserted
and Illuminated fiber.
and Illuminated fiber.
Partially reconfigured keyboard showing resultant improvement.
Tools and Materials Detail:
• The optical fiber used is inexpensive PMMA plastic.
• The outside diameter of the fiber is 3mm.
• This type of fiber is easily cut with a razor blade.
• That results in a clear face that does not need polishing.
• A 3mm diamond reamer was used to create the fiber channel.
• This opening can be created by several other means.
• Precise forming of the hole for a friction fit ensures that no
adhesive is needed.
• The fiber should be in contact with the LED for maximum light transfer.
Conclusions:
• This technique produces a significant light intensity improvement.
• It avoids the need for soldering or other alterations to the PCB.
• The added components are passive and inexpensive.
• There is no added power consumption, which is beneficial for
wireless on-battery operation. More light reaches the keycap
for a given brightness setting, enabling lower current draw.
• While this ‘light-pipe’ technique is established in electronics
chassis panel design, it does not appear to have been applied
commercially to mechanical keyboard switches as of 2025.
• Ideally, keyswitches could have this capability molded into the
body by switch manufacturers. This would obviate the need
for end-user modification as described in this document.
• This improvement can be beneficial regarding various types
of vision impairment.
Enhanced Backlighting for Mechanical Keyboards (How-To)
Produced in Oregon USA
