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Bulgarian research organization offers license for braille screen device

Country of Origin: Bulgaria
Reference Number: TOBG20190130001
Publication Date: 31 January 2019


A Bulgarian research team is working in the field of creating 3D models of historical objects and 3D printing of tactile matrices for visually impaired people. The researchers offer a new braille screen device helping visually impaired people, which offers advantages related to the technical development of the screen. The research team is looking for companies interested in a license agreement.


The Bulgarian research team is working mainly in the domain of 3D printing of historical objects and tactile matrices. The researchers offer a new technology for development of a braille display. The device visualizes Braille alphabet and graphics as well as pictures for those people.Nowadays there is no developed such device for graphical purposes.
The braille display will allow blind users to "see" the screen and give feedback according to the resolution and the “pixel” density of the screen. It can be used like assisted computer interface, presenting Windows icons for visual impaired people.
The graphical Braille display represents a matrix, comprised of a base with fixed electromagnets.They are arranged, including an outer cylindrical magnetic core in which is positioned a winding magnetic core (coil), locking (capping) up the cylindrical magnetic core at the top side. A winding magnetic core locking up the cylindrical magnetic core at the bottom side is placed.The magnetic cores are equipped with axial holes.Into the space between the windings, is placed a movable non-magnetic cylindrical body, carrying an axially magnetized permanent cylindrical magnet, as well as a non-magnetic needle. The needle is passing axially through the permanent magnet and the axial holes of the magnetic cores. On the top side of the permanent magnet is arranged a ferromagnetic disc having an axial hole.On its underside is arranged a ferromagnetic disc with an axial hole. The upper disc and the upper magnetic core have cylindrical poles and the lower magnetic core and the lower disc have conical poles. Above the electromagnets is placed a lattice. The needles pass through the openings.
The actuator that is a part of the Braille Display is a linear electromagnetic micro drive. The mover is a permanent magnet. Its magnetization direction is along the axis of rotational symmetry. The upper and lower coil are connected in series. This connection is constructed so that the flux created by each of them is in opposite directions in the mover zone. By choosing the proper power supply polarity, the motion of the mover will be in desired direction. For example, in order to have motion of the mover in the upper direction, the upper coil has to be supplied in a way leading to the creation of an air gap magnetic flux, which is in the same direction as the one of the flux created by the permanent magnet. The lower coil in this case will create magnetic flux which is in opposite direction to the one of the magnetic flux created by the permanent magnet. In this case motion up will be observed. In order to have motion down, the lower coil should be supplied in a way so that its flux is in the same direction as the flux by the permanent magnet. The upper coil then will create magnetic flux in opposite direction. In order to fix the moving part to the Braille dot, non-magnetic shaft is used. Additional construction variants of the actuator have also been considered, in which two small ferromagnetic discs are placed on both sides - upper and lower - of the moving permanent magnet. This actuator is also energy efficient, as energy is used only for changing the position of the moving part from lower to upper and vice versa. Both at lower and at upper position, no energy is used. At these positions, the mover is kept fixed due the force ensured by the permanent magnet (sticks to the core).
The research team is looking for partners for signing a license agreement of the new technology and product.


Advantages and Innovations

The proposed development offers the following advantages:
i) the retention of the needles in their final positions does not require an external power supply, it is provided by the permanent magnet;
ii) the lack of additional energy source allows a very precise control of the feed force creating the tactile feedback;
iii) an intermittent power supply voltage allowing an extremely low power consumption (only for moving the needle from one end to the other), as well as more efficient use of materials and reducing of the size of the matrix;
iv) extremely low electric and mechanical time constants, resulting in very good velocity and dynamic characteristics;
v) a considerably broader range of the obtainable tactile feedback due to the fact that all electromagnets can be operated simultaneously and synchronously, which gives the operator a more realistic and closer to reality tactile perception;
vi) extremely high positioning accuracy of the needles and stability of the retaining forces into their final positions;
vii) the chosen propulsion method is distinguished by its exceptional reliability and trouble - free operation and requires no additional settings and service;
viii) the technology as a whole, with its simplicity and easy maintenance, is convenient for the realization of the matrix.

Stage Of Development

Field tested/evaluated

Requested partner

The research team would like to find companies signing a license agreement about the innovative braille screen device and technology.

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