Input Key Subassembly Recessed Perimeter Lightguide Panel
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Solution Overview
Problem
Current communication devices face challenges in providing both tactile feedback and controlled light distribution for key highlighting, as the increased height of the key actuator and dome switch interferes with the light-restricting film, leading to unintended light leakage and confusion for the user.
Innovation Solution
The input key subassembly incorporates a lightguide panel with a recessed perimeter region and a dome overlay panel, where the lightguide panel features a translucent material and an opaque material bonded together, reducing the gap between components to minimize light emission and electrostatic discharge, while maintaining tactile feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If interference is added to the key actuator and dome to improve tactile feedback, then tactile feedback is improved, but the increased height applies pressure against the light-restricting film causing light to leak and erroneously highlight other keys
Solution Approach 1:
The patent introduces a vertical recessed perimeter region in the lightguide panel, creating a multi-level vertical structure. This dimensional change allows the light-restricting film to be positioned in a recessed area that is vertically separated from the dome switch actuator, eliminating the harmful light leakage while preserving the necessary interference for tactile feedback.
Solution Approach 2:
The recessed perimeter region acts as an intermediary structure between the light-restricting film and the dome switch actuator. This intermediate recessed space allows the film to be held in a position where it is not directly pressed by the actuator, thereby mediating the conflict between tactile feedback requirements and light leakage prevention.
2Measurement precision
If the light-restricting film is used to control light distribution, then key highlighting accuracy is improved, but the film is pressed by the dome switch actuator causing unintended light emission
Solution Approach 1:
By creating a vertically recessed perimeter region, the patent positions the light-restricting film in a different vertical dimension relative to the dome switch actuator. This vertical separation maintains the film's light-controlling function for accurate key highlighting while preventing the actuator from pressing the film and causing erroneous illumination.
Solution Approach 2:
The recessed perimeter region is designed in advance to prevent the harmful effect of light leakage. By pre-positioning the light-restricting film in the recessed area, the design anticipates and counteracts the potential harm of the actuator pressing the film, thereby preventing erroneous key illumination before it can occur.
3Object-generated harmful factors
If gap between lightguide panel and dome overlay panel is reduced to minimize light leakage, then light control is improved, but electrostatic discharge may occur
Solution Approach 1:
The recessed perimeter region creates a nested structure where the light-restricting film is positioned within the recessed area of the lightguide panel. This nesting allows the film to be close to the panel surface for effective light control while the recessed geometry provides space for electrostatic discharge management, preventing both light leakage and electrostatic hazards.
Data Source
AI summary
An input key subassembly for a handheld communication device is dislosed herein. The input key subassembly includes a dome overlay panel and a lightguide panel. The dome overlay panel includes a dome overlay layer and a dome switch having a peak facing frontally. The dome overlay layer has a front face located adjacent to the backside of the lightguide panel. The lightguide panel has at least one keystem and is located above a respective dome switch. A recessed perimeter region about the keystem has a height relative to the backside of the lightguide panel that is less than a height between the front side of the lightguide panel and the backside of the lightguide panel.