Illuminated Pushbutton Switch With Light Pipe
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Solution Overview
Problem
In low-light environments, such as in automobiles, conventional pushbutton switches are difficult to locate and operate without additional lighting, posing a challenge for easy identification and functionality.
Innovation Solution
An illuminated pushbutton switch assembly featuring a light emitting diode (LED) on a printed circuit board that illuminates a light pipe through a hollow plunger, providing consistent low-level lighting for switch location and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a light emitting diode and light pipe are added to illuminate the switch, then the switch becomes easily identifiable in low-light conditions, but the device complexity increases
Solution Approach 1:
The light pipe is positioned within the plunger structure, and the LED is mounted on the printed circuit board inside the switch body. This nesting arrangement allows the lighting components to be integrated into the existing switch structure without requiring separate housing or external mounting, thereby reducing overall device complexity while achieving illumination.
Solution Approach 2:
The light pipe acts as an intermediary component that transfers light from the LED to the plunger surface. This mediator enables efficient light transmission and distribution across the switch face, improving visibility without requiring the LED to be directly mounted on the visible surface, thus simplifying the overall design.
2Ease of operation
If a light emitting diode is continuously powered to illuminate the switch, then the switch remains visible at all times, but energy consumption increases
Solution Approach 1:
The lighting system is designed to operate periodically rather than continuously. The LED illuminates the switch during nighttime or low-light conditions when visibility is needed, and remains off during daytime when ambient light provides sufficient visibility. This periodic operation significantly reduces energy consumption while maintaining switch visibility when required.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables the switch to be easily identified and operated in low-light conditions, ensuring reliable functionality and user convenience by casting light through the plunger, independent of the switch's operational state.
Implementation Method 1
A light emitting diode (LED) 12, and surface mounted resistor 13 are mounted on the bottom of the PC board
Implementation Method 2
The light emitting diode illuminates a light pipe which casts a light through the plunger of the switch
Data Source
AI summary
A lighted pushbutton switch assembly has a printed circuit board in the bottom of a housing, with an LED mounted on the board. A switch operating plunger at the top rotates a ratchet and electrical contact member whenever the plunger is depressed. The contact member engages conductive paths on the top of the PC board and moves from path to path as it is rotated to change the state of the switch. A transparent light pipe over the LED transmits light through the plunger. The light pipe fits through the ratchet and is rotated by the ratchet to rotate the electrical contact member.