Braille Display Using Time-Reversal Wave Focusing
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Solution Overview
Problem
Existing Braille displays are bulky, fragile, expensive, and energy-intensive due to the need for multiple actuators and continuous power supply to maintain pin positions, limiting their size and efficiency in displaying Braille characters.
Innovation Solution
A reconfigurable-surface device with pins that can adopt two stable positions, using a waveguide and actuators controlled by the time-reversal wave focusing method to switch positions without continuous energy, allowing for reduced actuation size and simultaneous activation of multiple pins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If one actuator is used per pin to enable independent dot actuation, then each Braille character can be displayed accurately, but the device size becomes substantial and complex
Solution Approach 1:
A single actuator is designed to control multiple pins through the waveguide mechanism, allowing one actuator to perform the function of multiple individual actuators. The actuator generates waves that propagate through the waveguide to actuate specific pins at different positions, eliminating the need for separate actuators for each pin and significantly reducing device size.
Solution Approach 2:
The waveguide serves as an intermediary element between the actuator and the pins. Instead of directly connecting actuators to each pin, the waveguide transmits mechanical waves from a single actuator to multiple pins, enabling indirect control and reducing the overall number of actuators required while maintaining precise control over pin actuation.
2Stability of the object's composition
If continuous electrical power is supplied to coils to hold pins in position, then pin position stability is maintained, but energy consumption becomes very high
Solution Approach 1:
The system uses periodic wave generation to actuate pins rather than continuous power supply. The actuator generates wave pulses that propagate through the waveguide to displace pins to desired positions, and then the system waits for the pins to return to their initial position using elastic deformation, creating a periodic action pattern that eliminates continuous energy consumption while maintaining position stability.
Solution Approach 2:
The waveguide and pin structure are designed to be self-returning through elastic deformation. After the actuator generates a wave pulse to displace a pin, the pin automatically returns to its initial position without requiring continuous power supply. The system leverages the elastic properties of the waveguide and pin to provide the return force, eliminating the need for continuous electrical power to maintain pin positions.
3Force
If substantial electric current is used to activate pins, then pin actuation force is sufficient, but the number of pins that can be actuated simultaneously is limited
Solution Approach 1:
The waveguide enables sequential actuation of multiple pins through time-periodic wave propagation. The actuator generates wave pulses that travel through the waveguide and actuate pins in sequence rather than simultaneously, allowing the system to overcome the current limitation by using temporal separation to activate multiple pins one after another.
Solution Approach 2:
The system transitions from spatial parallel actuation (simultaneous pin activation) to temporal sequential actuation by introducing the time dimension. The waveguide allows the actuator to control pins in a sequential manner through wave propagation timing, effectively increasing the number of actuated pins by using time rather than requiring simultaneous high current for multiple pins at once.
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
The solution enables a compact, energy-efficient tactile display that can independently activate each Braille dot without continuous power, reducing the size and energy consumption of the device while maintaining precise control over pin positions.
Implementation Method 1
a control unit configured to control said at least one actuator using the time-reversal wave focusing method, such that it generates a wave in the waveguide located at the pin, which triggers the appearance of an out-of-plane pulse in the waveguide and the displacement of said pin
Implementation Method 2
the holding means are bistable, which makes it possible not to require energy to hold the pin in either of the positions
Implementation Method 3
the bistable holding means are of magnetic type, the energy supplied by the actuator is sufficient to switch the pin from one stable position to the other
Data Source
AI summary
Tactile display including a display surface equipped with holes, a waveguide plate, equipped with holes, pins, each pin being slidably mounted in a hole of the display surface and a hole-of the waveguide plate in a direction between a first position and a second position, actuators fastened to the waveguide plate triggering an out-of-plane displacement of the waveguide plate, and a control unit controlling the actuators according to the time-reversal wave focusing method, in such a way that the actuators generate a wave in the waveguide plate located at the pin(s) to be activated, which generates a pulse in the waveguide plate and triggers the displacement of the pin(s) which switch(es) from the first position to the second position, a holder for holding the pin in each of the positions.