Optical Key Assembly Layout for Sub-1u Laptop Keys
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Solution Overview
Problem
Conventional optical key switches are limited to keys of a standard base size (1u) and cannot be fitted to smaller keys due to space constraints in laptops or notebooks, making it impossible to use highly sought-after optical switches for smaller keys.
Innovation Solution
An input key assembly featuring an elastic deformable shell-like structure and an optical sensing arrangement that includes a peripheral base portion, an apex portion, and a plunger-like element, which interrupts a light beam when the keycap is depressed, allowing for optical detection and enabling the use of optical switches in keys smaller than the standard size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If conventional optical key switches are used, then optical switching function is achieved, but the key size cannot be smaller than standard base size (1u)
Solution Approach 1:
The conventional optical key switch is segmented into separate functional components: the elastic deformable shell-like structure (providing mechanical actuation) and the optical sensing arrangement (detecting key press). This segmentation allows the optical sensing part to be miniaturized and integrated into smaller key layouts while maintaining the optical switching function.
Solution Approach 2:
The optical sensing arrangement is nested within the key structure, with the light beam transmission path integrated through the substrate and the plunger-like element positioned within the elastic deformable shell-like structure. This nested configuration enables optical switching functionality to be accommodated within smaller key footprints.
2Area of moving object
If key size is reduced to fit laptop constraints, then space utilization is improved, but optical switches cannot be fitted
Solution Approach 1:
The conventional mechanical optical switch is replaced with a hybrid system combining an elastic deformable shell-like structure (mechanical) and an optical sensing arrangement (optical). The optical sensing arrangement uses light beam transmission and interruption detection instead of purely mechanical contacts, enabling reliable detection in smaller key sizes while maintaining optical switching capability.
Solution Approach 2:
The design changes the physical parameters of the key switch system by using an elastic deformable shell-like structure with specific geometric features (peripheral base portion, apex portion, plunger-like element) that enable optical detection. The light beam parameters (transmission path, interruption detection) are optimized for miniaturized key configurations, maintaining reliability while reducing size.
3Adaptability or versatility
If standard optical key switch design is used, then optical detection is achieved, but the structure cannot accommodate smaller key layouts
Solution Approach 1:
The optical sensing arrangement utilizes the vertical dimension (light beam transmission through the substrate thickness) rather than only the horizontal plane. The light beam travels vertically through the substrate and is interrupted by the plunger-like element's movement along the longitudinal axis, enabling compact horizontal footprint while maintaining optical detection functionality.
Solution Approach 2:
The elastic deformable shell-like structure acts as a flexible mechanical element that transmits key press force while allowing the optical sensing arrangement to remain compact. The shell's elasticity enables the plunger-like element to move vertically for optical detection without requiring large horizontal space, thus reducing the overall footprint area.
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
Enables the implementation of optical switching technology in keys smaller than the standard base size, overcoming the size limitations of conventional optical key switches and providing a functional alternative for smaller keys in input devices.
Implementation Method 1
an optical sensing arrangement disposed on the substrate to transmit a light beam and sense an interruption to the light beam
Implementation Method 2
an elastic deformable shell-like structure disposed between the substrate and the keycap... when the keycap is depressed to deform the elastic deformable shell-like structure for collapsing the apex portion relative to the peripheral base portion
Data Source
AI summary
An input key assembly including: a keycap; a substrate; an elastic deformable shell-like structure disposed between the substrate and the keycap; and an optical sensing arrangement disposed on the substrate to transmit a light beam and sense an interruption to the light beam. The elastic deformable shell-like structure includes a peripheral base portion in abutment with the substrate; an apex portion in abutment with the keycap; and a plunger-like element extending away from underneath the apex portion, wherein a free-end of the plunger-like element is opaque. The elastic deformable shell-like structure and the optical sensing arrangement are arranged in a manner such that the free-end of the plunger-like element interrupts the light beam when the keycap is depressed to deform the elastic deformable shell-like structure for collapsing the apex portion relative to the peripheral base portion to move the plunger-like element along a longitudinal axis of the plunger-like element.