Keyboard Key Press Detection with Pivoting Displacement Members
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Solution Overview
Problem
Existing keyboard devices face challenges in accurately detecting key press information due to dimensional and mounting errors in keys and hammers, leading to deviations in the clearance between sensors and detected parts, which affects the accuracy of key press detection.
Innovation Solution
A keyboard device configuration with a displacement member that pivots on a holder mounted to a substrate, reducing dimensional and mounting errors, and a detection method that uses a sensor to detect displacement of the displacement member relative to a coil, ensuring precise clearance settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the detected part is provided at the key as in the related art, then key press information can be detected, but dimensional errors and mounting errors accumulate causing the clearance to deviate from design value
Solution Approach 1:
The system is divided into separate functional components: the key unit (with key and hammer) is separated from the sensor unit (with coil and detected part). The detected part is specifically positioned on the hammer rather than the key, allowing independent positioning and reducing cumulative errors from key manufacturing variations.
Solution Approach 2:
The hammer acts as an intermediary component that transmits the key press motion to the detected part. By placing the detected part on the hammer rather than directly on the key, the system uses the hammer as a mediator to achieve more precise and consistent clearance positioning, since the hammer's position relative to the sensor can be more accurately controlled than key dimensions.
2Ease of manufacture
If multiple components (key, hammer, detected part) are assembled with tolerances, then the device can be manufactured, but clearance deviations occur affecting detection accuracy
Solution Approach 1:
By separating the detection function from the key structure itself and placing it on the hammer, the system allows each component to be manufactured independently with standard tolerances while achieving consistent overall clearance. The sensor unit and key unit can be manufactured separately and assembled with more predictable positioning.
Solution Approach 2:
The detected part is pre-positioned on the hammer at a specific location that facilitates accurate clearance control. This preliminary positioning on the hammer (rather than requiring precise key dimensions) establishes a more reliable reference point for sensor alignment during assembly.
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 configuration allows for high-accuracy detection of key press information by minimizing errors and maintaining consistent clearance between the detected part and the sensor, improving design flexibility and reducing the risk of sensor output overshoot.
Implementation Method 1
a coil 57 (sensor) generating a magnetic field is formed on a substrate 56
Implementation Method 2
since a current (magnetic field) flowing through the coil 57 changes due to relative displacement of the metal plate 55 (detected part) with respect to the coil 57
Data Source
AI summary
A detected part is provided at a displacement member acting in conjunction with a white key or a hammer. Since the displacement member is capable of being formed smaller compared to the white key and the hammer, dimensional errors are less likely to occur in each displacement member. Further, since the displacement member is configured to be pivotally supported on a relatively small holder mounted to a substrate rather than on a chassis, mounting errors of each displacement member are also less likely to occur. By reducing the dimensional errors and the mounting errors, a clearance between a coil and the detected part is easily set to a dimension according to a design value at each key. Thus, key press information of each key can be detected with high accuracy.