Off-Center Key Top Pressing Part for Illuminated Switch
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Solution Overview
Problem
In input devices with mechanical push button switches, arranging a light source and push button switch off-center on the key top can lead to inconsistent operation, as the push button switch may not close reliably when pushed from an unintended location, due to key top distortion.
Innovation Solution
The input device design includes a key top with a pressing part positioned off-center, supported by arms connected to a frame, ensuring the push button switch is pressed reliably even when pushed from an off-center location, and enhanced distinguishability through lighting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the light source is arranged on the back side of the key top to illuminate it for enhanced distinguishability, then the visual visibility of the key top is improved, but the pressing part must be arranged off-center which causes key top distortion and prevents the push button switch from reliably closing
Solution Approach 1:
The patent applies asymmetry by intentionally positioning the pressing part off-center on the key top, aligned with the light source position. This asymmetric arrangement accepts the distortion caused by off-center pressing as a trade-off to maintain both illumination effectiveness and switch activation reliability through proper alignment of the pressing part with the light source.
Solution Approach 2:
The pressing part serves as an intermediary element that transfers the pressing force from the key top to the push button switch. By positioning the pressing part to extend toward the push button switch and aligning it with the light source, it mediates between the illumination requirement and the switch activation requirement, ensuring reliable closing action even with off-center arrangement.
2Shape
If the pressing part is arranged in the central place on the key top for symmetric design, then the structural balance is improved, but it cannot be arranged in the central place when a light source is present, requiring off-center arrangement
Solution Approach 1:
The patent deliberately adopts asymmetric arrangement by positioning the pressing part off-center to align with the light source. This resolves the conflict between symmetric design and manufacturing flexibility by accepting asymmetric positioning as the optimal solution that accommodates both the light source placement and the pressing function.
Solution Approach 2:
The pressing part is designed with local quality differentiation - it has a pressing portion that contacts the push button switch and an extending portion that aligns with the light source. This local differentiation allows the pressing part to fulfill multiple functions (pressing and light alignment) despite its off-center position, maintaining ease of manufacture while achieving the required arrangement.
3Reliability
If the push button switch is arranged opposite to the pressing part, then the functional alignment is improved, but when the pressing part is off-center, pushing from the opposite location causes distortion and prevents reliable closing
Solution Approach 1:
The patent applies asymmetry by positioning both the pressing part and the push button switch off-center in alignment with each other. This asymmetric functional alignment ensures that when the key top is pressed, the pressing part reliably activates the switch despite the off-center location, maintaining both functional alignment and operation consistency through coordinated asymmetric positioning.
Solution Approach 2:
The pressing part is designed to extend toward the push button switch, creating a direct mechanical feedback path. When the key top is pressed, the pressing part immediately transmits the force to the switch, providing tactile and mechanical feedback that confirms reliable activation. This feedback mechanism ensures consistent operation despite the off-center arrangement.
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 improves the reliability of the push button switch's closing action and enhances the device's distinguishability by ensuring the push button switch activates consistently, even when pushed from an unintended location, while maintaining visibility through illumination.
Implementation Method 1
Two connection parts opposite to each other are prepared on the periphery of the key top, in an upper right portion and a lower left portion in planar view, for instance, and connected to the frame by a pair of arms each having spring characteristics. When the key top is pushed, the pair of arms is curved with respect to the frame so as to allow the displacement of the key top toward a board.
Implementation Method 2
arranging one or more light sources such as light emitting diodes (LEDs) on the back side (board side) of the key top so as to illuminate the key top from the back side
Data Source
AI summary
An input device including an operation key arranged in an opening of a panel is provided. The input device also includes a light source and a push button switch each being arranged in a position opposite an opening on a board. The operation key includes: a key top having a pressing part extending toward the push button switch. The pressing part is arranged in a position separated from a center position in planar view of the key top on a line that is parallel to a line connecting connection parts of the key top, which are connected with one pair out of one or more pairs of arms, and passes through the center position. The push button switch is arranged in a position on the board opposite an arrangement position of the pressing part.