Solenoid Haptic Control for Thin Low-Cost Touch Panels
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Solution Overview
Problem
Existing vibration presenting devices for touch panels, such as those in car navigation systems, face challenges in providing strong haptic feedback while reducing device cost and thickness, particularly in using expensive magnets for vibration actuators.
Innovation Solution
The use of an electromagnetic actuator driven by a solenoid without a magnet, employing a control device that supplies drive current pulses to generate vibrations suitable for haptic feedback, with a movable part supported by plate-shaped elastic parts for efficient thrust generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a vibration actuator using a magnet is employed to provide strong haptic feedback, then the haptic feedback strength is improved, but the device cost and thickness increase
Solution Approach 1:
The patent replaces expensive permanent magnets with a solenoid-based electromagnetic actuator that uses temporary electromagnetic fields generated by pulse signals. This substitution with cheaper components directly reduces device cost while maintaining the ability to generate sufficient thrust for haptic feedback through controlled electromagnetic forces
Solution Approach 2:
The patent changes the operating parameters by using pulsed voltage signals instead of continuous power, and by optimizing the solenoid coil specifications (turns, wire diameter, winding pattern) to maximize thrust output. This parameter optimization enables the solenoid actuator to achieve adequate haptic feedback strength without requiring expensive magnet materials
2Force
If a vibration actuator using a magnet is employed to provide strong haptic feedback, then the haptic feedback strength is improved, but the device thickness increases
Solution Approach 1:
The patent transitions from a radial magnetic field configuration (typical of motor-based actuators requiring significant radial space) to an axial electromagnetic force configuration in the solenoid actuator. This dimensional reorientation allows the generation of thrust in the primary direction of interest while minimizing the actuator's footprint in perpendicular dimensions, thereby reducing overall device thickness
Solution Approach 2:
The patent employs dynamic pulse signaling to activate the solenoid only when haptic feedback is needed, rather than maintaining continuous electromagnetic fields. This dynamic operation allows the use of lighter, thinner components that can deliver high peak forces on demand without requiring the robust, thick construction needed for continuous high-force generation
3Ease of manufacture
If a solenoid without magnet is used to reduce cost, then the device cost is reduced, but the thrust generation efficiency decreases
Solution Approach 1:
The patent applies periodic pulse signals to the solenoid coil, creating repeated cycles of magnetic field generation and collapse. This periodic action allows the movable part to be driven in one direction during the active phase while the elastic body passively returns it during the inactive phase, effectively converting unidirectional solenoid thrust into bidirectional vibration motion and improving overall thrust utilization efficiency
Solution Approach 2:
The patent introduces plate-shaped elastic parts as an intermediary mechanical element between the solenoid actuator and the vibration panel. This elastic intermediary stores and releases mechanical energy, amplifies the solenoid's thrust output, and converts the solenoid's unidirectional motion into effective vibrational motion, thereby compensating for the inherently lower efficiency of solenoid-based actuation compared to magnet-based motors
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 reduces the cost and thickness of the device while efficiently generating thrust for haptic feedback, providing a comfortable operation feel similar to mechanical switches without the need for magnets, thus enhancing user experience and reducing power consumption.
Implementation Method 1
a vibration actuator that drives a movable part 40 to vibrate in a vibrating direction Z
Implementation Method 2
a movable part 40 supported by plate-shaped elastic parts 50 so as to be movable in a vibrating direction with respect to a fixing part 30
Data Source
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AI summary
Provided is a control device capable of reducing cost and thickness by using an electromagnetic actuator, and capable of efficiently generating a thrust suitable for a haptic feeling feedback to an operator who touches and operates thereto. The control device controls the electromagnetic actuator that drives an operation device supported to be elastically vibrated in one direction of a vibrating direction thereof; includes a current pulse supply unit configured to supply a plurality of drive current pulses to a coil of the electromagnetic actuator as a drive current for driving the operation device in response to a touch operation of the operation device; and an interval between peaks for each of the drive current pulses is in a range of 1/2 times to 1 times a vibration period of an elastic vibration.