Illuminated Key-Pad Assembly with Integrated Light Strip
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Solution Overview
Problem
Traditional illuminated key-pads in devices like cell-phones and PDAs suffer from light attenuation as it passes through multiple components, leading to reduced brightness and increased power consumption or shorter illumination duration.
Innovation Solution
The design incorporates a flexible light strip made of transparent or translucent material interposed between the key-caps and the flexible web, with each key-cap securely attached to the light strip and under-blocks to prevent light leakage, allowing direct light transmission and efficient illumination, eliminating the need for complex connections to the circuit board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light passes through multiple components to reach key-caps, then illumination is achieved, but light intensity is significantly attenuated
Solution Approach 1:
The patent extracts the light source (LED) from its traditional position on the circuit board and relocates it directly to the back of the key-pad assembly. This extraction eliminates the need for light to pass through multiple intermediate components, thereby reducing light attenuation and improving brightness efficiency
Solution Approach 2:
The patent introduces a light-reflecting member as an intermediary element positioned between the LED and the key-caps. This mediator reflects and redirects light efficiently toward the key-caps, maximizing light transmission while minimizing energy loss through the assembly
2Ease of operation
If LED is mounted in key-pad unit and connected by FCP connector, then illumination is provided, but device complexity increases
Solution Approach 1:
The patent merges the LED mounting structure directly with the key-pad assembly housing, eliminating the need for separate FCP connectors and wiring harnesses. This integration simplifies the overall device structure while maintaining the illumination function
Solution Approach 2:
The key-pad assembly is designed to serve multiple functions: it provides both the mechanical key structure and the illumination system through integrated LED mounting. This multi-functionality reduces the number of separate components and connections required
3Area of stationary object
If light-transmitting film is placed underneath whole key-pad unit, then illumination coverage is achieved, but light intensity to key-caps is reduced
Solution Approach 1:
Instead of using a uniform light-transmitting film across the entire key-pad unit, the patent employs localized light reflection and transmission paths that direct light specifically toward each key-cap. This local optimization ensures adequate illumination coverage while maintaining high light intensity at the key-cap surfaces
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 enhances key-pad illumination brightness, reduces power consumption, and allows for longer illumination times while providing a self-contained, easily assembled key-pad unit with improved key feel and reduced manufacturing complexity.
Implementation Method 1
a flexible light strip made of transparent or translucent material interposed between the key-caps and the flexible web
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
For a cell-phone or PDA, the rows of key-caps (29) include respective light-strips (41), which pick up light from respective LEDs (70) surface-mounted on the PCB (21). The light-strips are sandwiched between the key-caps and the key-switch actuators (56) (whereby the light-strips move with the keys when the keys are depressed). Sockets (45) for receiving the key-caps are co-molded to the light-strips. Sockets are provided in the resilient webs (52) of the keys for receiving under-blocks (47) co-molded to the light-strips.