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Simulated Button Press Via Lightpipe Reflection Disclosure Number: IPCOM000200540D
Publication Date: 2010-Oct-18
Document File: 2 page(s) / 31K

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The Prior Art Database


A method and structure for replacing a mechanical pushbutton with specially designed lightpipe and light sensor to increase system reliability.

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Simulated Button Press Via Lightpipe Reflection

Most technical devices are operated using button presses of one sort or another. Buttons in this disclosure refer to the use of a membrane, or piece of material which is depressed and activates an underlying component on an electronics board, sending an on/off or duration signal to a processing entity.

Buttons usually are designed such that some surface or interface provides an affordance of use to a user, and depresses to activate a switch on a circuit board. In a computing device, this requires the switch (and therefore the electronics board) to be relatively close to the surface of the activation surface.

When the system board is a distance away from the activation surface, a secondary piece of electronics (a small silicon board for example) is needed to receive the button press and a signal is then transmitted to the main electronics board. This secondary board often requires additional cost to the system, requires additional engineering work, and takes up valuable space in electronic devices. Other times, long switches are used to transmit the signal from the user interface surface to the main electronics board. This long moving part can be prone to failure, and is not often possible if the distance to be traveled is greater than a few inches. The current disclosure looks to address the problem of transmitting a signal from a user interface to an electronics board by eliminating the need for a long switch or secondary piece of silicon.

Instead of pressing a physical button, the user places his/her finger over the opening for a lightpipe (a piece of plastic used to transmit light from an LED on the main system board to the front of an electronic device). The blocked light reflects back into the machine, and the resulting increase in light is detected by a receiver on the system board. This triggers the simulated switch or button press.

Figure 1 (below) shows a side view of a system where the front user interface of an electronics device is a distance away from the main electronics board and a lightpipe is transmitting light from the board to the front of the machine.

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Figure 1. A side view of a system enclosure where the front user int...