Shared Light Pipe for Mobile Device LED and Sensor
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Solution Overview
Problem
The existing design of mobile communication devices is hindered by the need for separate light pipes for message indicators and light sensors, which occupy valuable space and detract from the device's appearance and portability.
Innovation Solution
A shared light pipe that transmits light from the message waiting LED in one direction and ambient light to an internal light sensor in the opposite direction, minimizing surface and PCB real-estate by allowing the LED and light sensor to be placed closer together.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate light pipes are used for message indicator and light sensor, then each component can be optimized independently, but the device size increases and surface real-estate is wasted
Solution Approach 1:
The patent combines the message indicator light pipe and the light sensor light pipe into a single shared light pipe structure. The light pipe serves dual functions: transmitting LED light to the display surface for message indication and guiding ambient light to the internal light sensor for backlight control. This merging eliminates the need for separate light pipes, reducing surface area occupation while maintaining independent optimization of both functions through separate optical paths within the shared structure.
2Reliability
If separate light pipes are used for message indicator and light sensor, then each component can function independently, but the number of components increases
Solution Approach 1:
The light pipe is designed as a multi-functional component that performs both message indication and light sensing functions. It universally serves as both a light transmission medium for the LED message indicator and a light guidance structure for the ambient light sensor, thereby reducing the total number of components while maintaining independent functionality of both systems through internal optical separation.
3Ease of manufacture
If LED and light sensor are placed far apart, then each component has sufficient space, but the device size increases
Solution Approach 1:
The patent implements a nested arrangement where the light sensor is positioned internally within the device housing, and the shared light pipe extends from the display surface down to the sensor location. This nesting allows the LED and light sensor to be placed close together in the vertical dimension while maintaining adequate spacing for manufacturing and assembly, thereby reducing overall device footprint without compromising manufacturability.
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
This solution reduces the size of mobile communication devices by consolidating the light pipe functionality, minimizing the number of components required and maintaining effective notification and backlight control.
Implementation Method 1
a light pipe (sometimes referred to as a light guide) for transmitting light via Total Internal Reflection (TIR) from the LED to the surface of the device
Implementation Method 2
transmitting ambient or surrounding light, in an opposite direction, to an internal light sensor for controlling the backlight
Data Source
AI summary
A shared light pipe is set forth for transmitting light generated by a message waiting LED in a mobile communication device, in one direction, and transmitting ambient or surrounding light, in an opposite direction, to a light sensor for controlling a display backlight of the device. The light pipe includes an elongated first portion having a first end for receiving and transmitting light and external surfaces for reflecting light there through via total internal reflection (TIR), a second portion coextensive with the first portion for outputting light received at the first end and reflected through the first portion, and a second branch coextensive with the first portion for receiving and transmitting light for output at the first end.