WO2020183439A1 - Actionneur électromagnétique pour affichages tactiles - Google Patents

Actionneur électromagnétique pour affichages tactiles Download PDF

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Publication number
WO2020183439A1
WO2020183439A1 PCT/IB2020/052345 IB2020052345W WO2020183439A1 WO 2020183439 A1 WO2020183439 A1 WO 2020183439A1 IB 2020052345 W IB2020052345 W IB 2020052345W WO 2020183439 A1 WO2020183439 A1 WO 2020183439A1
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WO
WIPO (PCT)
Prior art keywords
magnet
fixed
pot magnet
movable
dot
Prior art date
Application number
PCT/IB2020/052345
Other languages
English (en)
Inventor
Ashok Sitaram Sapre
Original Assignee
Ashok Sitaram Sapre
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ashok Sitaram Sapre filed Critical Ashok Sitaram Sapre
Publication of WO2020183439A1 publication Critical patent/WO2020183439A1/fr

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Classifications

    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09B—EDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS
    • G09B21/00—Teaching, or communicating with, the blind, deaf or mute
    • G09B21/001—Teaching or communicating with blind persons
    • G09B21/003—Teaching or communicating with blind persons using tactile presentation of the information, e.g. Braille displays
    • G09B21/004—Details of particular tactile cells, e.g. electro-mechanical or mechanical layout
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/016—Input arrangements with force or tactile feedback as computer generated output to the user

Definitions

  • the present disclosure generally relates to technical field of tactile displays.
  • it pertains to an actuator for tactile display application that needs a dense array of remotely operated actuators. It also relates to a refreshable Braille cum graphic tactile display for the visually impaired persons.
  • Braille text characters are represented by patterns of raised dots in a Braille call that contains two columns of three dots, embossed on paper and felt with the fingertips.
  • Braille is used by millions of people all over the world in their native languages, and it provides a means of literacy for the visually impaired people.
  • Braille is embossed on thick paper making Braille books very bulky and heavy to handle.
  • the embossed Braille dots are replaced by movable dot pins that protrude above a sensing surface and lowered, when required, as per the pattern code of a new character to be displayed.
  • a general object of the present disclosure is to provide a device that broadens learning opportunities for visually challenged people by providing an affordable refreshable full page tactile display.
  • An object of the present disclosure is to provide an actuator that has low footprint and can be used for actuating dot pins in a refreshable full page Braille display.
  • Another object of the present disclosure is to provide an actuator that is light in weight, can be operated at low voltage, includes few parts and does not require any special manufacturing facilities.
  • an object of the present disclosure is to provide an electromagnetic actuator for full page tactile display that can withstand finger pressure of a user.
  • Another object of the present disclosure is to provide a refreshable full page Braille cum graphic display that enables change in pattern of dot pins between a Braille display and a graphic display, thereby allowing a single device to be used for Braille device as well as a graphic device.
  • the present invention relates to an electromagnetic actuator used for multi-line refreshable Braille and tactile graphic displays for visually impaired persons and for other applications that need miniature actuators individually or in dense arrays.
  • the actuator comprises of various configurations of plurality of magnetic assemblies known popularly as pot magnets, cap magnets or holding magnets. Pot magnets enclose a magnetic energy source in a container of a tubular or a channel shaped enclosure. Pot magnets have one active surface area that exerts a strong attraction force for ferrous alloy objects and attraction or repulsion force on assemblies that contain magnets.
  • the actuators of this invention comprise of a single or a pair of non-moving (fixed) electrically energized pot magnets whose magnetic polarity can be reversed with a pulse of electric current, to pull or push linearly, an adjacent movable pot magnet that contains a permanent magnet.
  • the movable pot magnet assumes stable end positions without use of power and the power is used only to switch the pole positions.
  • the movement of the movable pot magnet is utilized to raise or lower the dot pins that represent the braille dots.
  • FPM fixed pot magnets
  • MPM movable pot magnets
  • the actuators are placed vertically below the sensing surface and are arranged in a layout suitable for the Braille display and the graphic displays, both contained in one unit.
  • Such a display unit can be provided with a unique facility of changing the area occupied by the braille display and the graphics display so that adequate space for description in braille can be provided to the blind users to understand the graphics.
  • the actuator itself has low part count, low voltage operation, simple operating principle and construction. It uses standard materials and requires normal miniature parts manufacturing facilities. All these features result in an affordable price to the blind user.
  • FIG. 1 is across sectional view through the central axis of the disclosed electromagnetic actuator in accordance with a first embodiment, showing the movable pot magnet in a first stable position.
  • FIG. 2 is a across sectional view through the central axis of the electromagnetic actuator in accordance with the first embodiment, showing movable pot magnet in a second stable position.
  • FIG. 3 is a across sectional view through the central axis of the disclosed electromagnetic actuator in accordance with a second embodiment with a U shaped output bracket, showing the movable pot magnet in the first stable position.
  • FIG. 4 is a across sectional view through the central axis of the disclosed electromagnetic actuator in accordance with the second embodiment, showing the movable pot magnet in the second stable position.
  • FIG. 5 is a partial across sectional view through the central axis of the disclosed electromagnetic actuator in accordance with the second embodiment, showing a dot pin of a tactile display coupled to the movable dot magnet in the second stable position.
  • FIG. 6 is an alternative drive arrangement for coupling the dot pin to the movable pot magnet.
  • FIG. 7 is a cross sectional view through the central axis of the disclosed electromagnetic actuator in accordance with a third embodiment that has two movable pot magnets held between two fixed pot electromagnets.
  • FIG. 8A is aside view of the disclosed electromagnetic actuator with a locking arrangement, showing a locked dot pin in raised position.
  • FIG. 8B is a side view of the disclosed electromagnetic actuator with a locking arrangement, showing an unlocked and lowered dot pin.
  • FIG. 9A is a plan view of an exemplary layout of the disclosed electromagnetic actuators and the dot pin positions in a Braille cum a tactile graphics display, showing different patterns of the dot pins required for a Braille pattern and a graphic display pattern.
  • FIG. 9B is a partial vertical cross section along A-A of FIG.9A, showing arrangement for lateral shifting of dot pins for changing their pattern from the Braille pattern to the graphic display pattern and vice versa.
  • Embodiments explained herein relate to an electromagnetic actuator for multi-line/full page refreshable Braille and tactile graphic displays for visually impaired persons.
  • the present disclosure relates to a refreshable multi-line Braille and tactile graphic display for visually challenged persons, and an electromagnetic actuator used therein.
  • the disclosed electromagnetic actuator is based on pot magnets that exhibit relatively higher magnetic force concentrated in a small area due to a metal pot. The concentrated magnetic force in a small area leads to a small footprint for the actuator, which is essential to enable dense packing of actuators to actuate dot pins of a Braille or graphic tactile display.
  • the disclosed electromagnetic actuator includes a fixed pot magnet and a movable pot magnet.
  • the movable pot magnet is arranged coaxially with the fixed pot magnet for linear motion along a common axis of the fixed pot magnet and the movable pot magnet, between a first stable position, in which the movable pot magnet is closer to the fixed pot magnet, and a second stable position, in which the movable pot magnet is moved away from the fixed pot magnet.
  • the fixed pot magnet is an electromagnet having a coil configured to receive a current pulse to generate a magnetic flux adjacent an active face of the fixed magnet.
  • an active face of the movable pot magnet faces an active face of the fixed pot magnet, such that when the fixed pot magnet is supplied with the current pulse in a first direction, the generated magnetic flux of the fixed cup magnet results in an attraction force on the movable cup magnet to move the movable cup magnet to the first stable position.
  • the fixed cup magnet is configured such that after the current pulse in the first direction has ceased to flow through the coil, a remanent magnetic flux of the fixed cup magnet adjacent the corresponding active face applies an attraction force on the movable cup magnet to retain the movable cup magnet in the first stable position until a current pulse in a second direction that is opposite the first direction, is applied to the coil of the fixed cup magnet.
  • the fixed pot magnet may include: a FPM body made of a material with high magnetic permeability, and a core bar fixed to an inner side of a base of the FPM body.
  • the core bar may extend from the base till a rim of the FPM body.
  • the rim of the FPM body and a free end of the core bar together may form the active surface of the fixed pot magnet.
  • the coil may be wound around the core bar such that when the current pulse is passed through the coil the free end of the core forms one magnetic pole of the fixed pot magnet and the rim of the FPM body forms the other magnetic pole.
  • the core bar is made of a semi hard magnetic material that retains a remanent magnetic flux after the current pulse.
  • the movable pot magnet may include a MPM body made of a material with high magnetic permeability, and a permanent magnet fixed to an inner side of a base of the MPM body.
  • the permanent magnet may extend from the base of the MPM body till a rim of the MPM body such that the rim of the MPM body and a free end of the ring magnet form the active surface of the movable pot magnet with the free end of the ring magnet forms one magnetic pole of the movable pot magnet and the rim of the MPM body forms the other magnetic pole.
  • the core of the fixed pot magnet may be of tubular shape
  • the permanent magnet of the movable pot magnet may be a ring magnet
  • the actuator further includes an output shaft fixed to the base of the MPM body along the common axis such that it passes through the ring magnet of the movable pot magnet and the tubular core of the fixed pot magnet with an opposite end of the output shaft projecting out of an outer side of the base of the FPM body through a hole provided thereon.
  • a collar may be fitted to the projecting opposite end of the output shaft to retain the movable pot magnet and the fixed pot magnet together, an arrangement which shall allow the linear movement of the movable pot magnet.
  • the electromagnetic actuator may be used in a refreshable full page Braille cum graphic tactile display, with the output shaft coupled to a dot pin of the refreshable full page Braille cum graphic tactile display.
  • the actuator may include a mounting sleeve located around the FPM body and coupling the fixed pot magnet to a base plate.
  • the mounting sleeve may be configured to guide the movable pot magnet during the linear movement of the movable pot magnet through a pair of extension plates fixed to outer side the MPM body and guided in a pair of slots in the mounting sleeve.
  • the actuator may further include an inverted U shaped output bracket fixed to the extension plates.
  • the electromagnetic actuator of this embodiment may be used in a refreshable full page Braille cum graphic tactile display with the output bracket coupled to a dot pin of the full page Braille cum graphic tactile display to move the dot pin to a raised position and to return the dot pin to lowered position.
  • the actuator may include a mechanical locking arrangement to automatically lock the dot pin in the raised position.
  • the FPM body of the movable pot magnet and the MPM body of the fixed pot magnet for the actuator with locking arrangement may be channel shaped, and the locking arrangement may include: an output plate coupled to the movable pot magnet, the coupling between the output plate and the movable pot magnet allowing a small relative movement between the output plate and the movable pot magnet; wherein a dot pin of a tactile display is coupled to the output plate for movement of the dot pin between a raised position and a lowered position.
  • It may further include a pair of resilient lock levers fitted on either side of the output plate, which may extend downwards towards the movable pot magnet and the fixed pot magnet along outside of channel legs of the movable pot magnet and the fixed pot magnet; a pair of lock release levers fixed on an open side face of the channel legs of the movable pot magnet extending down towards the fixed pot magnet; a pair of outward protuberances on the channel leg; and a lock release tab on each of the lock levers.
  • An upward movement of the movable pot magnet shall result in a lower end of the lock levers engaging with the corresponding protuberance, thereby locking the dot pin in the raised position.
  • a downward movement of the movable pot magnet results in the lock release levers engaging with the corresponding lock release tab to disengage the lock levers from the protuberances to allow lowering of the dot pin.
  • An aspect of the present disclosure relates to a refreshable full page Braille cum graphic display that is based on the disclosed electromagnetic actuators configured to actuate the dot pins of the display between a lowered position and a raised position.
  • the display includes a top board with an overlay of a flexible barrier film, a plurality of dot pins arranged in a pattern through corresponding cavities in the top board such that an upper end of each of the dot pins touches the overlay from below and a plurality of the disclosed electromagnetic actuators arranged below the dot pins.
  • the movable pot magnet of each of the actuators is coupled to a corresponding dot pin such that when the movable pot magnet is in the first stable position the corresponding dot pin lifts up the overlay for a tactile perception, and in the movable pot magnet is in the second stable position the corresponding dot pin does not lift up the overlay.
  • the dot pins may be made of a magnetic material and coupled to the movable cup magnet through a corresponding magnet that allows lateral movement of the corresponding dot pin.
  • the display may include a plurality of washers disposed below the top board by means of washer retaining sheet and the at least some of the dot pins may pass through the retaining sheet in a close sliding fit with the corresponding washers.
  • the top board and the washer retaining sheet may have elongated cavities to allow lateral movement of the at least some of the dot pins to change their pattern between a Braille pattern and a graphic display pattern.
  • a dot pin pusher plate may be used for lateral movement/shifting of the at least some dot pins.
  • the dot pin pusher may be held in hand and placed between the raised dot pins on top of the overlay to selectively move the corresponding dot pins to change the pattern of the dot pins.
  • the remaining dot pins may be made of a plastic material, and coupled to the movable pot magnet through a cross bar. These dot pins may be in a close sliding fit with the top board for linear movement along their axis. These dot pins may be arranged in a fixed Braille pattern.
  • Yet another aspect of the present disclosure relates to a method for changing a pattern of the dot pins in a tactile display, the method comprising the steps of: providing a full page tactile display, moving the dot pins that are required to be moved for changing the pattern to respective raised positions; placing a dot pin pusher plate on the top board against the raised dot pins; and pushing the dot pin pusher plate in direction the dot pins are to be moved;
  • the display includes a top board; a plurality of dot pins arranged in a pattern through corresponding cavities in the top board for a linear movement between a raised position, in which the dot pins project above a top surface of the top board, and a lowered position, in which the dot pins do not project above the top surface of the top board, and a plurality of electromagnetic actuators arranged below the dot pins.
  • Each of the electromagnetic actuator is coupled to a corresponding dot pin of the plurality of dot pins to selectively move the corresponding dot pin to the raised position a tactile perception.
  • the coupling between the electromagnetic actuator and the corresponding dot pins is configured to allow lateral movement of the pins within corresponding cavities in the top board.
  • the cavities in the top board are configured to change the pattern from a from Braille pattern to the graphic display pattern or vice versa.
  • An embodiment of the present disclosure also relates to a refreshable multi-line Braille and tactile graphic display for visually challenged persons, which is based on the disclosed electromagnetic actuator.
  • the disclosed refreshable multi-line Braille and tactile graphic display for visually challenged persons includes dot pins and the corresponding actuators arranged such that pattern of the dot pins may be changed manually by a user between a Braille pattern and a graphic display pattern, thereby enabling the user to use a common device both as a pure Braille device, or a combination of Braille and a graphic display device, or as a pure graphic display device.
  • the disclosed electromagnetic actuator is based on pot magnets that exhibit relatively higher magnetic force concentrated in a small are due to a metal pot.
  • the concentrated magnetic force in a small area leads to a small footprint for the actuator, which is essential to enable dense packing of actuators to actuate dot pins of a Braille or tactile graphic display.
  • the disclosed electromagnetic actuator (also referred simply as actuator and the two terms used interchangeably hereinafter) comprises a plurality of magnetic assemblies known as pot magnets, also referred to in the related art as cap magnets or holding magnets. Because of their construction, the pot magnets have one active face that exerts a strong attraction force for ferrous alloy objects and attraction or repulsion force on magnetically charged bodies. This force is much higher than a force exerted by a bare, unenclosed magnet.
  • the magnetic energy source of a pot magnet can be a strong permanent magnet, or an electromagnet in the form of a core made of a semi hard permanent magnetic material or of a soft magnetic material, over which multi-run coil is placed.
  • the electromagnets is based on semi hard magnetic materials, which retain magnetic polarity after the current is stopped (referred to in the art as remanent flux), the retained magnetic polarity or the remanent flux can be reversed by applying a pulse of electrical energy of a correct polarity.
  • the electromagnets is based on soft magnetic corer, there shall be no magnetic flux without a current through the coil.
  • a permanent magnet or an electromagnet is centrally located inside a cup shaped body or a channel shaped body made of a soft magnetic material.
  • One end of the magnet or of the electromagnet is attached to the base of the cup or of a channel and its opposite end extends up to level of the open face (rim) of the cup or up to the level of the legs of the channel.
  • This construction of the pot magnet makes the rim of the cup, or the face area of the channel legs, as one magnetic pole (South or North) and the open face of the central permanent magnet or of the electromagnet as the opposite magnetic pole.
  • the open end face of the cup or of the channel becomes the origin of attractive or repulsive forces and it will be called as the active surface area of the pot magnet.
  • Other body surfaces of the pot magnets do not cause much magnetic flux leakage and reduce magnetic interference between adjacent actuators.
  • the actuator 100 includes a fixed pot magnet (FPM) 2 and a movable pot magnet (MPM) 20 held together coaxially on the actuator’s central axis 4.
  • Both the pot magnets FPM 2 and MPM 20 have a cup shaped body 10 and 10A respectively (also referred simply as body hereinafter) that enclose their internal parts.
  • the cups 10 and 10A are made of soft magnetic alloy that has high relative permeability offering a low resistance to the passage of magnetic flux.
  • the FPM 2 includes a tubular core bar 6 (also referred simply as core or as bar and all these terms used interchangeably hereinafter) located in the centre and fixed in a base of the cup 10.
  • the core 6 is made of semi hard magnetic material and it extends up the active surface area 16 of the FPM 2.
  • a coil 8 of required turns is placed over the core 6.
  • the coil 8 is configured to receive a DC current pulse, on which the coil 8 magnetizes the bar 6 with a polarity as dictated by the current polarity /direction, as would be well known to those skilled in the art. After the current pulse, a remanent magnetic flux in the bar 6 forms one magnetic pole at an end of bar 6 and an opposite magnetic pole at the rim of the cup 10.
  • the MPM 20 includes a ring type magnet 22 located inside the cup shaped body 10A and placed centrally on a base of the cup shaped body 10A and secured with glue 32.
  • the ring magnet 22 is made from hard magnetic material which has high coercivity and high remanent flux density.
  • An active surface area 24 is formed containing a magnetic pole on the top face of the ring magnet 22, and an opposite magnetic pole on the rim face of cup 10A of the MPM 20.
  • the actuator 100 further includes a nonmagnetic longitudinal output shaft 12, whose one end is secured rigidly to the base of cup 10A, and passes along the central axis 4 through the ring magnet 22 and through a hole 7 in the tubular core bar 6 with a nonmagnetic spacer 18 placed between the active surface area 16 of the FPM 2 and the active surface area 24 of the MPM 22.
  • the actuator 100 further includes a collar 13 fitted to the other/free end of the output shaft 12, which holds the FPM 2 and the MPM 22 coaxially together, but allows a linear movement 14 between them to achieve the intended function of the actuator.
  • the coil 8 is indicated as small circles on either side of the rod 6. These circles are filled with dots (.) on one side and crosses (x) on the other side of the rod 6, to show the direction of the current pulse (referred to as a first direction) that creates magnetic polarities as shown by letters N and S (north and south poles) in the active face 16 of the FPM 2. As shown in the FIG. 1, these magnetic polarities being opposite to the polarities of the active face 24, MPM 20 is attracted towards the FPM 2 and this motion may be used to raise a Braille dot pin (not shown) for sensing. This movement stops when the spacer 18 is clamped between the active surface areas 16 and 24 and forming a minimum air gap length 26 equal to the thickness of the spacer 18.
  • the flux linkage between the two pot magnets FPM 2 and MPM 20 is maximum in this minimum air gap position. This creates the highest attraction force between them. This large force resists well the finger pressure on the dot pin.
  • the path and direction of the flux is shown by dashed lines 30 in the minimum air gap position.
  • This attracted position of MPM 20 remains stable (referred to as a first stable position) without any requirement of current through the coil 8 due to the remanent flux of the core 6 and the ring magnet 22.
  • FIG.2 Another stable end position of the MPM 20, away from the FPM 2, referred to as a second stable position, is shown in FIG.2. It is obtained by sending a current pulse of opposite polarity to the coil 8. This switches the magnetic polarity at the active face 16, making it the same as the polarity at the active face 24 and repelling the MPM 24 till the collar 13 touches the base of the cup 10 of the FPM 2, achieving a maximum air gap position 28 as illustrated in FIG. 2. In this position, there is no interlinking of flux between FPM 2 and MPM 20 and the flux path and its direction is denoted by a dashed line 31. The repelling force at the maximum air gap 28 is much less than the attraction force at the min. air gap 26, yet large enough to keep the position stable.
  • FIG.s 3 - 4 Another embodiment of the actuator 101 is shown in FIG.s 3 - 4 wherein the actuator 101 has the similar pair of a fixed pot magnet (FPM) 2 A and a movable pot magnet (MPM) 20A and they operate the same way.
  • the FPM 2A has a solid core bar 6A of semi hard magnetic material.
  • a mounting sleeve 34 fixed outside of the cup 10. The mounting sleeve 34 is used to fix the actuator on to a base plate 36 of the actuator. The sleeve also acts as guide for the linear movement of the MPM 20A.
  • the base plate 36 provides power connections to the coil 8 of the actuator.
  • a disc shape permanent magnet 22A of high coercivity and remanent flux density is fixed centrally with glue 32 inside the cup 10A.
  • Two outward projecting extensions plates 38 are attached to the base of the cup 10A.
  • An output bracket 40 of inverted U shape is fixed to the extensions plates 38.
  • the bracket 40 controls the travel 14 of the MPM 20A and also provides attachment means for the dot pin (not shown) that is raised and lowered.
  • magnet 22A has larger area than the ring magnet 22, giving higher operating forces and the disc magnets are much cheaper than ring magnets used in the embodiment 100.
  • the externally fitted output bracket 40 also simplifies the display assembly procedure.
  • FIG. 5 is a cross sectional view through the central axis 4 of the second embodiment of the actuator, i.e. actuator 101, in a maximum air gap position 28,i.e. the second stable position of the MPM 20A, and showing a drive arrangement of a dot pin 50.
  • FIG.5 shows a top board 44 of the display that has an overlay of a flexible barrier film 48 which becomes a sensing surface 46 of the display.
  • a longitudinal dot pin 50 of ferrous material is configured within a cavity 51 in the board 44 such that the an upper end of the dot pin 50 touches the overlay film 48 from below in the second stable position of the actuator 101.
  • the opposite end, i.e. the lower end, of the dot pin 50 is held attracted to a magnet 52.
  • Magnet 52 is fixed on the output bracket 40. Such a magnetic attachment of the dot pin 50 to the bracket 40 allows a free pin movement even though axis 53 of the pin movement may be different than the central axis 4 of the actuator.
  • Numeral 54 indicates the flux path in the actuator 101 without a current supplied to the coil 8.
  • the dot pin 50A of a plastic material is shown slidingly attached to a cross bar 41 that is held in vertical extensions 41 of the output bracket 40. This arrangement serves the same purpose of allowing free lateral movement of the dot pin 50A.
  • actuators 100 and 101 the minimum air gap position 26, i.e. the first stable position, with maximum holding force is used to keep the pin raised and maximum air gap position 28, i.e. the second stable position of the MPM 20A, with minimum repelling force to keep the dot pin lowered.
  • both the stable positions may require large holding forces.
  • an electromagnetic actuator 102 as shown in FIG. 7, is proposed.
  • a movable double pot magnet assembly 56 made by joining back to back two MPM 20A of (shown in FIGs.3-4) with their 2 active surface areas 24 facing outwards in opposite direction. Assembly 56 is placed between two pot type electromagnets 58 on a common central axis 4. Electromagnets 58 have identical construction as FPM 2 (shown in FIG. 3), but made entirely of soft magnetic material having no remanent magnetic flux. Active surface area 16 of each electromagnet 58 lies opposite the active surface area 24 of the assembly 56 with the spacer 18 between them.
  • a joining sleeve 60 holds the 2 electromagnets 58 together and the sleeve acts also as a guide for a movement of the assembly 56.
  • Assembly 56 has two stable positions, each stable position of being attracted towards one of the two electromagnets 58 with a minimum air gap 26 and a maximum holding force, and simultaneously, a maximum air gap 28 and a low attraction force with the other of the two electromagnets 58.
  • Stable position of the assembly 56 is changed by sending a current pulse to both the electromagnets whereby repelling force is generated at the interface of minimum air gap 26 and an attraction force is generated at the interface of maximum air gap 28. This push pull action causes the assembly 56 to move between the first stable position and the second stable position with both the stable positions having a large holding force.
  • FIG. 7 illustrates only the principle of operation of the actuator 102 and all other details are omitted for clarity.
  • FIG.8A and FIG.8B show yet another embodiment 103 of the actuator that has MPM 20B placed below the top board 44 and above the FPM 22B.
  • This embodiment uses a channel type construction of the pot magnets that facilitates automatic mechanical locking of the dot pin 50 in its raised position. It also provides an automatic lock release to allow lowering of the dot pins using an attraction force generated between the two pot magnets 20B and 22B .
  • an output plate 66 is attached to the MPM 20 with rivets 68, allowing a small relative movement between the output plate 66 and the MPM 20. The relative movement is somewhat less than half of the travel of the MPM 20B.
  • Two resilient lock levers 70 are fitted on either side of the output plate 66 and extend downwards towards the MPM 20B and FPM 22B along outside of the channel legs72 of both the pot magnets.
  • two lock release levers 74 are fixed on the open side face 76 of the channel leg 72 of the MPM 20B extending down towards FPM 22B.
  • Levers 70 and 74 also serve the purpose of providing a guide for linear travel of the MPN 20B.
  • a travel limit pin 78 is fitted to the output plate 66, which touches the top board 44 to set the maximum desired travel of the MPM 20B.
  • An outward protruberance 80 on the channel leg 72 and a lock release tab 84 on the lock lever70 are additional elements provided for locking and lock release operations.
  • end 82 of the lock lever70 rests on the protruberance 80 and prevents lowering of the output plate 66 and the raised dot pin 50 against the finger pressure exerted while reading the mechanical locking withstands much larger force than the magnetic latching between the fixed pot magnet and the movable pot magnet.
  • This disengagement allows complete assembly of MPM 20B (elements output plate 66, magnet 52 and the dot pin 50) to move down to the final rest position of minimum air gap and make the dot pin 50 lie below the sensing surface 46.
  • This embodiment uses a solid core bar 6B of soft magnetic material which requires much less power to change the magnetic polarity, thus reducing the power requirement to refresh the display.
  • An aspect of the present disclosure relates to a tactile device for blind that provides a tactile graphic display as well as Braille display to meet learning needs to of blind users. For a good presentation, one should be able to place the graphics and the braille at any suitable place in a tactile display, each having sufficient display area.
  • a text in Braille has a non- uniform spacing whereas dot spacing for the graphics needs a uniform grid of dots.
  • the actuators that create the raised dots are placed directly below the dot position, however by creating the ability for lateral movement of the dot pins, a common layout of the actuators can be designed useful for graphics and braille display and a desired part of the display can be set for the braille pattern and the other part can be utilized for a tactile graphics output; just like a text book page showing figures with the descriptive text. This arrangement is explained with the help of FIG. 9Aand 9B.
  • An exemplary Braille display 200 in FIG. 9A has two 6 dot Braille cells 86 in which pattern of the dot pins 50 positions is indicated as a x (cross) symbol. The pattern of these positions has a pitch distance 88 and the cells are separated by a distance 89. Pattern of the dot pin positions for the graphics display 300 are shown as filled dots ( ⁇ ) and are at a vertical pitch 88, (same as the Braille dot pitch) and are at a horizontal pitch 90. Position of the actuators that activate the dot pins are indicated as circles 91 that enclose the dot pin position symbols.
  • the dot pins 50 are on the central axis of the respective actuators and in the Braille display 200 the dot pins are away from the central axis of the respective actuators, as shown in FIG.5.
  • cell separation pitch 89 is about 1.5 times the Braille dot pitch 88 and for this ratio the, horizontal pitch 90 of graphics pattern is set at 1.25 times the pitch 88.
  • the vertical pitch 88 being the same for both the patterns, the dot pin pattern of Braille can be changed to the graphics pattern by increasing the horizontal pitch 88 to the pitch 90. The reverse action will revert to the earlier Braille pattern.
  • This change of pitch is effected by manually moving horizontally, the raised dot pins by a distance 92, which in value is about l/8th of the Braille dot pitch 88.
  • FIG.9B shows details of arrangement to laterally move raised dot pins 50 for change of the pattern from Braille pattern to the graphic display pattern or vice versa.
  • the dot pins 50 rest on the magnets 52 (which is a part of the assembly MPM 20B (not shown here, refer to FIG. 5) and extends in an upward direction through a washer retaining sheet 96, then through a washer 94 and then through cavities in the top board 44.
  • the washer 94 has a close sliding fit with the dot pins 50.
  • Oblong cavities 98 are provided in the washer retaining sheet 96 and the top board 44 for the lateral/sideway (horizontal) movement of the dot pins.
  • a dot pin pusher plate 99 held in the hand and placed on the top board 44 between the raised pins 50 is used to move the required no. of dot pins 50 for changing the pattern from Braille pattern to the graphic display pattern or vice versa.
  • the present disclosure provides a device that broadens learning opportunities for visually challenged people by providing an affordable refreshable full page tactile display.
  • the present disclosure provides an actuator that has low footprint and can be used for actuating dot pins in a refreshable full page Braille display.
  • the present disclosure provides an actuator that is light in weight, can be operated at low voltage, includes few parts and does not require any special manufacturing facilities.
  • the present disclosure provides an electromagnetic actuator for full page tactile display that can withstand finger pressure of a user.
  • the present disclosure provides a refreshable full page Braille cum graphic display that enables change in pattern of dot pins between a Braille display and a graphic display, thereby allowing a single device to be used for Braille device as well as a graphic device.

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Abstract

Est divulgué un actionneur électromagnétique basé sur des aimants en pot, présentant un aimant en pot fixe (FPM), et un aimant en pot mobile (MPM) agencé de manière coaxiale avec l'aimant fixe pour un mouvement linéaire selon un axe commun entre une première position stable et une seconde position stable. L'aimant mobile est un électro-aimant comprenant une bobine qui reçoit une impulsion de courant pour générer un flux magnétique adjacent à une face active de l'aimant fixe. Une impulsion de courant dans une direction appropriée déplace l'aimant mobile entre les deux positions stables. L'aimant fixe est configuré de sorte qu'après l'impulsion de courant, un flux magnétique rémanent retient l'aimant en pot mobile dans la position stable correspondante jusqu'à ce qu'une autre impulsion de courant dans la direction opposée soit appliquée. Un affichage graphique tactile à afficheur Braille dynamique qui permet un changement de motif de points saillants entre un afficheur Braille et un affichage graphique, est également divulgué.
PCT/IB2020/052345 2019-03-14 2020-03-14 Actionneur électromagnétique pour affichages tactiles WO2020183439A1 (fr)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2755002C1 (ru) * 2021-02-01 2021-09-09 Общество с ограниченной ответственностью «ТИФЛОПАЛ» Усовершенствованный тактильный дисплей с объединенными компонентами устройств ввода и вывода
US20210375158A1 (en) * 2020-05-29 2021-12-02 Abenezer Ayana Modular refreshable braille display system
US11436943B2 (en) * 2018-04-24 2022-09-06 Polymer Braille Inc. Magnetically programmable actuators for tactile conveyance of information
CN115171485A (zh) * 2022-08-04 2022-10-11 南京信息工程大学 一种电磁驱动式盲文显示装置
EP4339922A1 (fr) * 2022-09-14 2024-03-20 Karlsruher Institut für Technologie Mécanisme d'actionnement, dispositif d'actionnement et procédés d'utilisation dudit mécanisme d'actionnement et dudit dispositif d'actionnement

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3616029A1 (fr) * 2017-04-29 2020-03-04 Luitpold Greiner Affichage tactile à actionneur linéaire axisymétrique magnétique bistable pourvu de contour de pôle et matrice de commutation et aide visuelle optique tactile correspondante

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3616029A1 (fr) * 2017-04-29 2020-03-04 Luitpold Greiner Affichage tactile à actionneur linéaire axisymétrique magnétique bistable pourvu de contour de pôle et matrice de commutation et aide visuelle optique tactile correspondante

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
JUAN JOSE ZARATE ET AL.: "Using Pot-Magnets to Enable Stable and Scalable Electromagnetic Tactile Displays", IEEE TRANSACTIONS ON HAPTICS, vol. 10, no. 1, 1 January 2017 (2017-01-01), XP011643041, DOI: 10.1109/TOH.2016.2591951 *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11436943B2 (en) * 2018-04-24 2022-09-06 Polymer Braille Inc. Magnetically programmable actuators for tactile conveyance of information
US20210375158A1 (en) * 2020-05-29 2021-12-02 Abenezer Ayana Modular refreshable braille display system
US11640769B2 (en) * 2020-05-29 2023-05-02 Abenezer Ayana Modular refreshable braille display system
US11915607B2 (en) 2020-05-29 2024-02-27 Brailleazy, Inc. Modular refreshable braille display system
RU2755002C1 (ru) * 2021-02-01 2021-09-09 Общество с ограниченной ответственностью «ТИФЛОПАЛ» Усовершенствованный тактильный дисплей с объединенными компонентами устройств ввода и вывода
CN115171485A (zh) * 2022-08-04 2022-10-11 南京信息工程大学 一种电磁驱动式盲文显示装置
EP4339922A1 (fr) * 2022-09-14 2024-03-20 Karlsruher Institut für Technologie Mécanisme d'actionnement, dispositif d'actionnement et procédés d'utilisation dudit mécanisme d'actionnement et dudit dispositif d'actionnement

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