Refreshable braille display cell and system

Abstract

REFRESHABLE BRAILLE DISPLAY CELL AND SYSTEM A braille display cell (100) comprises a reading surface (102) including a plurality of holes (104), a first guide wall (106) coupled to the reading surface (102); and a plurality of braille pin assemblies (110) Each of the plurality of braille pin 5 assemblies (110) includes a braille pin (112) and a rotary actuator (114. The braille pin (112) extends in a longitudinal direction along the first guide wall (106), and includes a tip (304) on a first end and a slot (302) on a second end that is opposite to the first end. The braille pin (112) is coaxially aligned with a respective hole (104), and is movable in the longitudinal direction through the respective hole. The 10 rotary actuator (114) that includes a crankshaft (206) engaged with the slot (302). The rotary actuator (114) rotates to cause the braille pin (112) to move in the longitudinal direction. Reference figure: FIG. 1B

Description

REFRESHABLE BRAILLE DISPLAY CELL AND SYSTEMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority of EN Provisional Application No. 202441078531, filed October 16, 2024 entitled ‘A REFRESHABLE BRAILLE DISPLAY CELL WITHDOT RETURN MECHANISM AND DOT SENSINGSYSTEM’, the contents of which are incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure generally relates to braille systems and devices for individuals who are blind or visually impaired. More particularly, the present disclosure relates to braille display cells featuring a mechanism that facilitates cost-effective, minimalist, and robust design.BACKGROUND

[0003] Braille is a system of touch reading and writing for visually impaired people in which raised dots represent letters of the alphabet. It can be read either on embossed paper or by using refreshable braille displays that can dynamically display braille characters and can be connected to computers or mobile phones. A refreshable braille display or braille terminal is an electromechanical device for displaying the braille characters, usually by means of round-tipped pins raised through holes in a flat surface. The refreshable braille display contains braille display cells, where each cell contains either 6 or 8 dots, with each cell capable of displaying a braille character by selectively raising or lowering the pins of the dot combination of that braille character. The pins are raised or lowered electromechanically and are controlled by a microcontroller.

[0004] However, the traditional refreshable braille displays present notable design limitations. These traditional refreshable braille displays employ piezoelectric biomorph reeds to raise the pins but lack a provision to retract the pins and rely purely on gravity. Further, the pins require a spring element to recede, andsince piezoelectric biomorph reeds have a very low lifting force, this results in the failure of pins rising as the reeds are not capable of overcoming the spring force, or if the pins can be raised, the pins are held with a very low holding force. Additionally, the holes on the reading surface may get clogged by foreign debris, dust, or often dead skin cells from a user’s fingers, which results in the failure of pins to return to their receded position due to frictional resistance.

[0005] Accordingly, there is a need for technical advancements in these traditional refreshable braille displays that solve the abovementioned problems.SUMMARY

[0006] Present disclosure provides a refreshable braille display that is easy to assemble, cost-effective, and exhibits a robust and reliable design. To this end, one aspect of the present disclosure provides a braille display cell. The braille display cell comprises a reading surface including a plurality of holes, a first guide wall that is coupled to the reading surface, and a plurality of braille pin assemblies. Each of the braille pin assemblies includes a braille pin extending in a longitudinal direction along the first guide wall. The braille pin includes a tip on a first end and a slot on a second end that is opposite to the first end. The braille pin is coaxially aligned with a respective hole of the plurality of holes, and is movable in the longitudinal direction through the respective hole. Each of the plurality of braille pin assemblies further includes a rotary actuator that includes a crankshaft engaged with the slot, where the rotary actuator is configured to rotate to cause the braille pin to move in the longitudinal direction.

[0007] In some example embodiments, the first guide wall includes a plurality of guide members, where a subset of the plurality of guide members blocks a transverse movement of the braille pin.

[0008] In some example embodiments, the crankshaft includes a first member that forms a rotational shaft of the rotary actuator and a second member that has a central axis spaced from a rotational axis of the first member by an eccentricity.The second member is coupled to the first member at one end, and extends into the slot at an opposite end thereof. The crankshaft is engaged with the slot by the second member that extends into the slot.

[0009] In some example embodiments, the second member is detachably coupled to the first member.

[0010] In some example embodiments, the rotary actuator is configured to rotate to cause the first member to rotate. The rotation of the first member causes the second member engaged with the slot to follow a circular path relative to the rotational axis of the first member and simultaneously slide along an inner face of the slot. The rotation of the first member is limited to a first maximum angle in a first rotational direction to position the second member at a first position within the slot and a second maximum angle in a second rotational direction to position the second member at a second position within the slot. The first rotational direction is opposite to the second rotational direction.

[0011] In some example embodiments, in a case where the second member is at the first position, the braille pin is at a raised position, and the tip of the braille pin protrudes out of the respective hole in the raised position. In a case where the second member is at the second position, the braille pin is at a lowered position, and the tip of the braille pin recedes into the respective hole in the lowered position.

[0012] In some example embodiments, the rotary actuator rotates in the first rotational direction based on a first polarity of a voltage, and the rotary actuator rotates in the second rotational direction based on a second polarity of the voltage.

[0013] In some example embodiments, the first maximum angle and the second maximum angle are based on at least one of the eccentricity of the second member, a size of the slot, a shape of the slot, a position of the slot, and a position of the first guide wall.

[0014] In some example embodiments, each of the plurality of braille pin assemblies further includes a housing that houses the rotary actuator.

[0015] In some example embodiments, the crankshaft has a protrusion thereon, and the first guide wall includes a first switch and a second switch, where the first switch is above a rotational axis of the crankshaft and the second switch is below the rotational axis of the crankshaft. The protrusion actuates one of the first switch or the second switch based on the rotation of the rotary actuator.

[0016] In some example embodiments, the braille display cell further includes a controller coupled to the first switch and the second switch, where the controller determines a position of the braille pin based on the actuation of one of the first switch or the second switch.

[0017] In some example embodiments, the controller detects that the determined position of the braille pin is incorrect with respect to a display output and provides a corrective signal to the rotary actuator based on the detection that the determined position of the braille pin is incorrect, where the corrective signal causes the rotary actuator to rotate, thereby moving the braille pin to a correct position.

[0018] In some example embodiments, the first switch and the second switch may correspond to elastic switches.

[0019] In some example embodiments, a braille display device is provided. The braille display device includes a stack of a plurality of braille display cells. Each of the plurality of braille display cells comprises a reading surface, a first guide wall, and a plurality of braille pin assemblies. The reading surface includes a plurality of holes, and the first guide wall is coupled to the reading surface. Each of the plurality of braille pin assemblies includes a braille pin and a rotary actuator. The braille pin extends, in a longitudinal direction, along the first guide wall. The braille pin includes a tip on a first end and a slot on a second end that is opposite to the first end. The braille pin is coaxially aligned with a respective hole of the plurality ofholes, and is movable, in the longitudinal direction, through the respective hole. The rotary actuator includes a crankshaft engaged with the slot, where the rotary actuator is configured to rotate to cause the braille pin to move in the longitudinal direction.

[0020] In some example embodiments, the braille display device includes a controller that is electrically coupled to the rotary actuator, where the controller selectively actuates, based on a display output, the rotary actuator to cause the braille pin to move in the longitudinal direction.

[0021] Other features and aspects of the present disclosure will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the features in accordance with embodiments of the present disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The following detailed description of the embodiments of the present disclosure will be better understood when read in conjunction with the appended drawings. The present disclosure is illustrated by way of example, and not limited by the accompanying figures, in which like references indicate similar elements.

[0023] FIG. 1A is a diagram that illustrates a perspective view of a braille display cell, in accordance with various embodiments of the present disclosure;

[0024] FIG. IB is a diagram that illustrates a side view of the braille display cell of FIG. 1 A, in accordance with various embodiments of the present disclosure;

[0025] FIG. 2A is a diagram that illustrates a side view of a rotary actuator, in accordance with various embodiments of the present disclosure;

[0026] FIG. 2B is a diagram that illustrates a side view of a rotary actuator, in accordance with another embodiment of the present disclosure;

[0027] FIG. 3 is a diagram that illustrates a side view of a plurality of braille pin assemblies, in accordance with various embodiments of the present disclosure;

[0028] FIG. 4 is a diagram that illustrates a cell case of the braille display cell of FIG. 1 A, in accordance with various embodiments of the present disclosure;

[0029] FIG. 5A is a diagram that illustrates vertical positions of a braille pin and sliding positions of a second member within a slot, in accordance with various embodiments of the present disclosure;

[0030] FIG. 5B is a diagram that illustrates a geometric relation of the second member of FIG. 5A with the slot of FIG. 5A, in accordance with various embodiments of the present disclosure;

[0031] FIGS. 6 A and 6B are diagrams that illustrate perspective views of a braille display cell, in accordance with another embodiment of the present disclosure;

[0032] FIG. 6C is a diagram that illustrates a perspective view of braille pin assemblies, in accordance with another example embodiment of the present disclosure;

[0033] FIG. 7 is a diagram that illustrates a stack of braille display cells, in accordance with an example embodiment of the present disclosure;

[0034] FIG. 8 is a diagram that illustrates a perspective view of a braille display cell, in accordance with an example embodiment of the present disclosure;

[0035] FIG. 9 is a diagram that illustrates a stack of braille display cells in accordance with another example embodiment of the present disclosure;

[0036] FIG. 10 is a diagram that illustrates a perspective view of a braille display system according to a modification of the braille display cell of FIG. 1, in accordance with an example embodiment of the present disclosure

[0037] FIGS. 11A and 11B are diagrams that illustrate a switch actuation mechanism corresponding to a raised position of a braille pin, in accordance with an example embodiment of the present disclosure;

[0038] FIGS. 12A and 12B are diagrams that illustrate a switch actuation mechanism corresponding to a lowered position of a braille pin, in accordance with an example embodiment of the present disclosure;

[0039] FIG. 13 is a block diagram that illustrates a closed-loop system implemented in a braille display system, in accordance with an example embodiment of the present disclosure; and

[0040] FIG. 14 is a diagram that illustrates a braille display device including a stack of braille display cells, in accordance with an example embodiment of the present disclosure.

[0041] Further areas of applicability of the present disclosure will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description of exemplary embodiments is intended for illustration purposes only and is, therefore, not intended to necessarily limit the scope of the present disclosure.DETAILED DESCRIPTION

[0042] The present disclosure is best understood with reference to the detailed figures and description set forth herein. Various embodiments are discussed below with reference to the figures. However, those skilled in the art will readily appreciate that the detailed descriptions given herein with respect to the figures are simply for explanatory purposes as the methods and systems may extend beyond the described embodiments. In one example, the teachings presented and the needs of a particular application may yield multiple alternate and suitable approaches to implement the functionality of any detail described herein. Therefore, any approachmay extend beyond the particular implementation choices in the following embodiments that are described and shown.

[0043] References to “an embodiment”, “another embodiment”, “yet another embodiment”, “one example”, “another example”, “yet another example”, “for example”, “for instance”, and so on, indicate that the embodiment(s) or example(s) so described may include a particular feature, structure, characteristic, property, element, or limitation, but that not every embodiment or example necessarily includes that particular feature, structure, characteristic, property, element or limitation. Furthermore, repeated use of the phrase “in an embodiment” does not necessarily refer to the same embodiment.

[0044] Traditional refreshable braille displays suffer from significant design limitations, including dependence on piezoelectric biomorph reeds with insufficient lifting force to overcome spring resistance, inability to actively retract pins (relying purely on gravity), and susceptibility to pin failure when holes become clogged with foreign debris, dust, or dead skin cells from users' fingers, resulting in frictional resistance that prevents pins from returning to corresponding receded position.

[0045] The present disclosure addresses these limitations by providing a refreshable braille display that is easy to assemble, cost-effective, and exhibits a robust and reliable design through an actuation mechanism that eliminates dependency on spring elements while ensuring consistent pin operation.

[0046] Specifically, the braille display cell includes a reading surface including a plurality of holes, a first guide wall coupled to the reading surface, and a plurality of braille pin assemblies. Each braille pin assembly includes a braille pin having a tip (for example, a dome-shaped tactile element) on a first end and a slot on a second end opposite to the first end, where the braille pin extends in a longitudinal direction along the first guide wall and is coaxially aligned with a respective hole of the plurality of holes. The braille pin assembly further includes a rotary actuator. The rotary actuator includes a crankshaft engaged with the slot. The rotary actuator rotates to cause the braille pin to move in the longitudinal direction, providing bothraising and lowering capabilities without depending on gravity or spring mechanisms.

[0047] Such a configuration of the braille display cell provides several technical advantages. For example, the inclusion of the crankshaft in the rotary actuator enables precise positional control of the braille pin through controlled rotation angles. The rotary actuator generates sufficient lifting force to overcome any frictional resistance from debris or dead skin cells that may accumulate in the plurality of holes. The first guide wall with guide members restricts transverse movement while allowing smooth longitudinal movement of the braille pin, ensuring consistent coaxial alignment with the respective hole. The elimination of spring elements reduces mechanical complexity and potential failure points while enabling the braille pin to maintain stable raised and lowered positions without continuous power consumption. The crankshaft sliding within the slot provides a mechanical advantage that converts rotational motion to linear motion with high reliability and repeatability.

[0048] Referring to FIG. 1 A, a diagram that illustrates a perspective view of a braille display cell 100 is shown, in accordance with various embodiments of the present disclosure. The braille display cell 100 may be one unit of a braille display device that is used to present information in braille format, allowing a user to read the information tactually.

[0049] In an embodiment, the braille display cell 100 includes a reading surface 102, a first guide wall 106 coupled to the reading surface 102, and a second guide wall 108 positioned opposite to the first guide wall 106. The reading surface 102 includes a plurality of holes 104. The braille display cell 100 further includes a plurality of braille pin assemblies 110, where each braille pin assembly 110 includes a braille pin 112 and a rotary actuator 114. For the sake of brevity, only one braille pin assembly, one braille pin, and one rotary actuator are labelled in FIG. 1 A.

[0050] In an example, the reading surface 102 may be a tactile interface surface through which braille pins 112 can protrude to form tactile dots readable by a user'sfingers. The plurality of holes 104 refers to apertures formed through the reading surface 102, where each hole of the plurality of holes 104 is dimensioned to allow a corresponding braille pin 112 to move longitudinally therethrough while maintaining coaxial alignment. In a non-limiting example, each of the plurality of holes 104 may be a machined or molded circular aperture to accommodate a cylindrical portion of the corresponding braille pin 112 while providing minimal clearance to prevent lateral displacement of the corresponding braille pin 112.

[0051] In an example, the first guide wall 106 may be attached perpendicularly to an edge of the reading surface 102 through mechanical fastening methods such as screws or bolts, adhesive bonding using structural adhesives, or integral molding where the first guide wall 106 and the reading surface 102 are formed as a single monolithic component.

[0052] The braille pin 112 may include a tip on a first end and a slot on a second end that is opposite to the first end. The first end with the tip is positioned toward the reading surface 102 and extends through the respective hole of the plurality of holes 104, while the second end with the slot is positioned away from the reading surface 102 toward the rotary actuator 114. The braille pin 112 extends in a longitudinal direction along the first guide wall 106 and is coaxially aligned with a respective hole of the plurality of holes 104. In an example, the tip may be a tactile element configured for user contact, having a dome-shaped or hemispherical configuration to provide optimal tactile sensation. The slot may be an elongated recess or through hole formed in the second end of the braille pin 112, having dimensions configured to receive and engage with an actuating member of the rotary actuator 114. In various examples, the braille pin 112 may be a monoblock or monolithic braille pin manufactured as a single integral component from materials such as engineering plastics including ABS, POM, or nylon, or from lightweight metals such as aluminum alloy. The rotary actuator 114 may be a micro DC motor, a micro AC motor, or similar rotational electromechanical device capable of bidirectional rotation with torque output sufficient to lift the braille pin112 and overcome any frictional resistance in a corresponding braille pin assembly 110.

[0053] In various embodiments, the braille display cell 100 may further include a plurality of housings 116, and each housing of the plurality of housings 116 houses the rotary actuator 114 of each braille pin assembly 110. Each housing of the plurality of housings 116 may be an enclosure structure configured to securely retain the rotary actuator 114 through press-fit engagement, snap-fit mechanisms, threaded connections, or the like. The plurality of braille pin assemblies 110 is positioned between the first guide wall 106 and the second guide wall 108, forming a box-like structure to complete the braille display cell 100.

[0054] Referring to FIG. IB, a diagram that illustrates a side view of the braille display cell 100 is shown, in accordance with various embodiments of the present disclosure. FIG. IB is explained in conjunction with FIG. 1 A.

[0055] As illustrated in FIG. IB, the first guide wall 106 includes a plurality of guide members 118 protruding out of the first guide wall 106. The plurality of guide members 118 is defined as structural elements that guide the movement of the braille pin 112 in a longitudinal direction along the first guide wall 106 and restrict lateral movement or transverse movement of the braille pin 112. In an example, the plurality of guide members 118 may include elongated ribs or rails extending parallel to a longitudinal axis of the braille pin 112, positioned to create channels or grooves that constrain the braille pin 112 movement. A subset of the plurality of guide members 118 blocks a transverse movement of the braille pin 112, thereby ensuring that the braille pin 112 maintains proper alignment during longitudinal movement. The transverse movement is defined as any displacement perpendicular to the longitudinal axis of the braille pin 112, including lateral, rotational, or angular deviations from the intended linear path.

[0056] The braille pin 112 is coaxially aligned with a respective hole of the plurality of holes 104, meaning that the longitudinal axis of the braille pin 112 coincides with a central axis of the respective hole. The rotary actuator 114 engageswith the braille pin 112 through a crankshaft mechanism described later in conjunction with FIGS. 2A and 2B. When the rotary actuator 114 rotates, the braille pin 112 moves in the longitudinal direction through the respective hole of the plurality of holes 104.

[0057] In an embodiment, a four-dot braille display cell 100 is exemplified that has four braille pin assemblies 110 and four housings 116 stacked vertically. The four housings 116 may be positioned on the left side of a center axis of the braille display cell 100. The center axis is defined as a vertical plane of symmetry dividing the braille display cell 100 into equal left and right sections. The four housings 116 are stacked such that each subsequent housing 116 is positioned at an offset towards the center axis from the previous housing 116. The offset arrangement is defined as a stepped configuration where each housing 116 is displaced horizontally toward the center axis by a predetermined distance to accommodate varying lengths of the braille pins 112 while maintaining proper alignment with the corresponding holes 104. For example, a second housing of the plurality of housings 116 is positioned at an offset from a first housing of the plurality of housings 116 towards the center axis, a third housing of the plurality of housings 116 is positioned at an offset from the second housing towards the center axis, and a fourth housing of the plurality of housings 116 is positioned at an offset from the third housing towards the center axis. This stepped arrangement enables the braille pins 112 of different lengths to reach the same reading surface level while maintaining coaxial alignment with their respective holes 104.

[0058] For the sake of brevity in FIGS. 1 A and IB, not all components are individually labeled with reference numerals. However, when a reference numeral is used herein to refer to components in the plural form, that reference numeral is intended to collectively denote multiple instances of the same or corresponding elements, and not merely the single element specifically labeled in the figures. For example, when reference is made herein to a braille pin 112, it may refer to any one of the individual braille pins included within the braille display cell 100; when reference is made to braille pins 112, it denotes multiple such braille pins. Similarly,braille pin assembly 110 refers to a single assembly, whereas braille pin assemblies 110 refer to multiple such assemblies.

[0059] Referring to FIG. 2A, a diagram that illustrates a side view of the rotary actuator 114 is shown, in accordance with various embodiments of the present disclosure. FIG. 2A is explained in conjunction with FIGS. 1 A and IB.

[0060] As illustrated in FIG. 2A, the rotary actuator 114 includes a main body 202, electrical wires 204 on a first end of the main body 202, and a crankshaft 206 on a second end of the main body 202 opposite to the first end. The first end of the main body 202 is positioned away from the braille pin 112, whereas the second end of the main body 202 is toward the braille pin 112. In an example, the main body 202 may be a cylindrical housing structure including various electromagnetic components, such as stator windings and rotor assemblies, that convert electrical energy to rotational mechanical energy. The electrical wires 204 may correspond to conductive elements (for example, copper conductors with insulating jackets) configured to deliver electrical power to the electromagnetic components within the main body 202. A voltage may be applied across the electrical wires 204 that causes the rotation of the rotary actuator 114. In an example, instead of the electrical wires 204, the rotary actuator 114 may include electrical contacts such as spring-loaded pins, or the rotary actuator 114 may rotate using electromagnetic induction through wireless power transfer mechanisms.

[0061] The crankshaft 206 is shown to include a first member 208 that forms a rotational shaft of the rotatory actuator 114 and a second member 210 having a central axis spaced from a rotational axis of the first member 208 by an eccentricity e. More specifically, the rotating shaft of the rotary actuator 114 is designed like a crank. In various embodiments, the first member 208 may be a cylindrical shaft element that protrudes from the main body 202 and has the rotational axis coinciding with a central axis of the main body 202. In various embodiments, the second member 210 may be an eccentric pin or rod element having the central axis that is offset from the rotational axis of the first member 208 by a predeterminedeccentricity distance e. In an example, the predetermined eccentricity distance e may range from 0.3 mm to 0.5 mm to achieve a linear displacement amplitude for the braille pin assembly 110. The eccentricity e may correspond to the radial distance between the rotational axis of the first member 208 and the central axis of the second member 210, determining the magnitude of linear motion conversion from the rotational input of the rotary actuator 114.

[0062] In various embodiments, the second member 210 may be mechanically coupled to the first member 208 through a rigid connection where both the first and second members 208, 210 are formed as a single monolithic component. The coupling between the first member 208 and the second member 210 ensures that when the first member 208 rotates with the rotary actuator 114, the second member 210 follows the same rotational motion while maintaining corresponding eccentric offset position. In alternative embodiments, the second member 210 may be detachably coupled to the first member 208 as shown in FIG. 2B.

[0063] Although the first member 208 and the second member 210 are positioned on the second end of the main body 202 that faces the braille pin 112 illustrated in FIGS. 1A and IB, the scope of the present disclosure should not be limited to this specific configuration, as the crankshaft 206 may be positioned at various locations relative to the main body 202 depending on the specific mechanical requirements and spatial constraints of the braille display cell 100.

[0064] Referring to FIG. 2B, a side view of the rotary actuator 114 is shown, in accordance with another embodiment of the present disclosure. FIG. 2B is explained in conjunction with FIGS. 1A-2A. As illustrated in FIG. 2B, the second member 210 is detachably coupled to the first member 208, thereby enabling field replacement or adjustment of the eccentricity for different braille pin displacement requirements. The second member 210 includes a third member 212 and a fourth member 214, where the third member 212 is defined as a coupling element configured to engage with the first member 208, and the fourth member 214 isdefined as an eccentric pin element positioned at the predetermined eccentricity distance from the rotational axis of the first member 208.

[0065] In an example, the third member 212 may include an aperture formed through one end thereof, where the aperture is dimensioned to receive and engage with the first member 208 through detachable mechanical coupling methods including press-fit engagement, threaded connection, snap-fit mechanisms, or the like. The fourth member 214 is positioned at the eccentricity e from a rotational axis of the third member 212, where the eccentricity e determines the linear displacement amplitude of the braille pin 112 when the rotary actuator 114 rotates. Since the fourth member 214 forms part of the second member 210, the eccentricity e of the fourth member 214 effectively defines the eccentricity of the second member 210 as a whole, meaning that the axis of the second member 210 is spaced from the rotational axis of the first member 208 by the same eccentricity distance e. Further, the rotational axis of the third member 212 is same as the rotational axis of the first member 208.

[0066] Thus, the second member 210 is detachably coupled to the first member 208 through the aperture of the third member 212, creating a connection that transmits rotational motion from the first member 208 to the second member 210 while maintaining the eccentric offset of the fourth member 214. This eccentric configuration enables the second member 210 to follow a circular path relative to the rotational axis of the first member 208 when the rotary actuator 114 rotates, thereby converting rotational motion into linear displacement of the braille pin 112 through the engagement of the fourth member 214 with the braille pin 112.

[0067] The detachable coupling between the first member 208 and the second member 210 may allow for modular assembly and maintenance of the rotary actuator 114, enabling replacement of the second member 210 without requiring complete disassembly of the braille display cell 100.

[0068] Referring to FIG. 3, a diagram that illustrates a side view of the plurality of braille pin assemblies 110 is shown, in accordance with various embodiments of the present disclosure. FIG. 3 is explained in conjunction with FIGs. 1 A-2B.

[0069] As illustrated in FIG. 3, the braille pin 112 includes a tip 304 on a first end and a slot 302 on a second end that is opposite to the first end, where the braille pin 112 may have an elongated body configuration between the first and second ends thereof. In various embodiments, the first end of the braille pin 112 may face the reading surface 102, whereas the second end of the braille pin 112 may face away from the reading surface 102. For example, the first end of the braille pin 112 may be proximal to the reading surface 102, whereas the second end of the braille pin 112 may be proximal to the corresponding rotary actuator 114.

[0070] The slot 302 corresponds to a recess formed in the second end of the braille pin 112, having dimensions configured to receive and engage with the second member 210 of the rotary actuator 114. In various embodiments, the slot 302 may be positioned on a bottom side of the braille pin 112 that faces away from the reading surface 102. The slot 302 may include inner faces that provide sliding surfaces for the second member 210 during rotational motion conversion.

[0071] In various embodiments, the braille pin 112 may have a cylindrical protrusion extending from the first end on a top side of the braille pin 112, which is opposite to the bottom side containing the slot 302. In an example, the cylindrical protrusion may terminate in a dome-shaped configuration forming the tip 304. The tip 304 may be a tactile element configured for user contact. In a non-limiting example, the tip 304 may have a hemispherical configuration to provide optimal tactile sensation for braille reading.

[0072] In various embodiments, the second member 210 may be positioned inside the slot 302 such that the braille pin 112 rests on the second member 210, thereby creating a mechanical coupling in which the rotary actuator 114 includes the crankshaft 206 engaged with the slot 302.

[0073] In an embodiment, the braille pins 112 of the plurality of braille pin assemblies 110 are of various lengths and are selectively raised or lowered to form different braille characters on the reading surface 102. The various lengths are defined as predetermined dimensions to accommodate the stepped arrangement of the actuator housings 116 (as described in conjunction with FIG. IB) while maintaining coaxial alignment with the respective holes 104. The braille pins 112 are selectively raised or lowered by an external drive circuit (not shown) that selectively applies voltage to a respective rotary actuator 114 engaged with each braille pin 112. In an example, the external drive circuit may be an electronic control system including voltage regulation components, switching circuits, and microcontroller interfaces configured to provide electrical control signals to individual rotary actuators 114 via the electrical wires 204.

[0074] In an example, when a voltage of positive polarity (e.g., a first polarity) is applied across the electrical wires 204, the rotary actuator 114 may rotate in a first rotational direction causing the first member 208 to rotate in the first rotational direction, where the rotation of the first member 208 causes the second member 210 to follow a clockwise circular path and simultaneously slide along the inner face of the slot 302, thereby raising the braille pin 112 to a raised position. The positive polarity voltage corresponds to an electrical potential difference applied with a predetermined voltage magnitude, where the positive terminal connects to one electrical wire 204 and the negative terminal connects to another electrical wire 204. In an example, the first rotational direction may be a clockwise rotational direction when viewed from the crankshaft 204 end of the rotary actuator 114. The clockwise circular path may correspond to the trajectory followed by the second member 210 as the second member 210 maintains eccentric offset distance while rotating about the rotational axis of the first member 208. In the raised position, the tip 304 protrudes out of the respective hole 104 such that a user can touch and feel the tip 304 as a raised dot. In an example, the raised position may correspond to a vertical displacement state where the braille pin 112 extends above the reading surface 102 by a certain height, for example, a height ranging from 0.6 mm to 0.9 mm.

[0075] In another example, when a voltage of negative polarity (e.g., a second polarity) is applied across the electrical wires 204, the rotary actuator 114 may rotate in a second rotational direction that is opposite to the first rotational direction causing the first member 208 to rotate in the second rotational direction, where the rotation of the first member 208 causes the second member 210 to follow a counterclockwise circular path and simultaneously slide along the inner face of the slot 302, thereby lowering the braille pin 112 to a lowered position. The negative polarity voltage corresponds to an electrical potential difference applied with reversed terminal connections compared to the positive polarity voltage, where the previously positive terminal becomes negative and the previously negative terminal becomes positive. In an example, the second rotational direction may correspond to a counterclockwise rotational direction when viewed from the crankshaft 204 end of the rotary actuator 114. In the lowered position, the tip 304 recedes into the respective hole 104. In an example, the lowered position may correspond to a vertical displacement state where the tip 304 of the braille pin 112 is positioned below or flush with the reading surface 102, creating a non-tactile condition for the user.

[0076] Referring to FIG. 4, a diagram that illustrates a cell case 400 of the braille display cell 100 is shown, in accordance with various embodiments of the present disclosure. FIG. 4 is explained in conjunction with FIGs. 1A-3.

[0077] As illustrated in FIG. 4, the reading surface 102, the first guide wall 106, a stack of the plurality of housings 116 attached to the first guide wall 106, and the plurality of guide members 118 protruding from the first guide wall 106 are integrally fused to form a single part, referred to as the cell case 400. In an example, the cell case 400 may be a monolithic structural component that integrates multiple functional elements into a unified assembly, manufactured through processes such as injection molding, 3D printing, or machining from a single block of material. In one example, the plurality of housings 116 may be configured in accordance with the shape and size of the main body 202 to accommodate the rotary actuator 114, such that the rotary actuator 114 can be snapped or press-fitted, but not limited to,into the housing 116 and securely retained therein. The snap-fit engagement corresponds to a mechanical coupling method where the rotary actuator 114 includes protruding features or flanges that elastically deform during insertion and then return to their original shape to create a secure retention mechanism within the housing 116. The press-fit engagement corresponds to an interference fit where an outer diameter of the main body 202 is slightly larger than an inner diameter of the housing 116, creating frictional retention through elastic deformation of a material of the housing 116.

[0078] Within the cell case 400, the braille pin 112 may be coupled with the second member 210 of the rotary actuator 114 and positioned between the plurality of guide members 118 to enable guided reciprocating movement exclusively in a longitudinal direction along the first guide wall 106, while restricting transverse displacement. The reciprocating movement corresponds to a bidirectional linear motion along a single axis, where the braille pin 112 can move upward to the raised position and downward to the lowered position while maintaining coaxial alignment with the respective hole 104.

[0079] In various embodiments, the second guide wall 108 may be fastened to the cell case 400, after the fitting of the plurality of braille pin assemblies 110 within the cell case 400, opposite to the first guide wall 106, such that the plurality of braille pin assemblies 110 is between the first guide wall 106 and the second guide wall 108, and the reading surface 102, the first guide wall 106, and the second guide wall 108 forms a closed-box like structure. The closed-box like structure may refer to an enclosed assembly that provides environmental protection and structural integrity while containing mechanical components of the braille display cell 100 within a defined volume of the cell case 400.

[0080] Referring to FIG. 5A, a diagram that illustrates vertical positions of the braille pin 112 and sliding positions of the second member 210 within the slot 302 is shown, in accordance with various embodiments of the present disclosure. FIG. 5A is explained in conjunction with FIGs. 1A-4. More specifically, FIG. 5Aillustrates vertical positions 502A - 502D of the braille pin 112 of the braille pin assembly 110 over time as the rotary actuator 114 housed within the housing 116 undergoes rotation in the first rotational direction.

[0081] As illustrated in FIG. 5A, at a first time instance, the braille pin 112 is in the lowered position 502A with the tip 304 inside the respective hole 104, and the second member 210 is below a rotational axis 504 of the rotary actuator 114 at a second position 506A (e.g., an initial position) within the slot 302. More specifically, in a case where the second member 210 is at the second position 506A, the braille pin 112 is at the lowered position 502A. The second position 506A corresponds to an angular orientation of the second member 210 where the braille pin 112 is at a lowest vertical displacement corresponding to the lowered position 502A. In an example, the second position 506A may correspond to a rotational angle between 160° and 180° from a vertical reference axis. In the lowered position 502A, the braille pin 112 rests upon the second member 210 and is therefore stable in the lowered position 502A without any external power to the rotary actuator 114.

[0082] Upon application of the positive polarity voltage across the electrical wires 204, the rotary actuator 114 rotates in the first rotational direction, causing the second member 210 to follow the circular path in the first rotational direction and simultaneously slide along the inner surface of the slot 302 to reach a first position 506B (e.g., a final position) within the slot 302. The first position 506B may correspond to the angular orientation of the second member 210 where the braille pin 112 achieves a maximum vertical displacement above the reading surface 102. In an example, the first position 506B may correspond to a rotational angle between 360° and 390° from the vertical reference axis. The circular and the sliding motion of the second member 210 lifts the braille pin 112 in the longitudinal direction, transitioning through intermediate vertical positions 502B and 502C, and then reaching a raised position 502D corresponding to the maximum vertical displacement. More specifically, in a case where the second member 210 is at the first position 506B, the braille pin 112 is at the raised position 502D. In the raised position 502D, the braille pin 112 is raised above the reading surface 102, and thetip 304 of the braille pin 112 protrudes out of the respective hole 104. The voltage applied across the electrical wires 204 can then be removed. Therefore, the second member 210 stays rotationally stable at the first position 506B such that no power is applied to keep the braille pin 112 raised. The rotational stability is achieved through the geometric relationship between the eccentricity of the second member 210, the dimensions of the slot 302, and the positioning constraints imposed by the first guide wall 106 and the second guide wall 108. Further, the second member 210 rotationally locks at the first position 506B. The rotational locking is defined as a mechanical constraint condition where the second member 210 cannot rotate beyond the first position 506B due to physical interference with the boundaries of the slot 302 and guide wall structure of the first guide wall 106. The braille pin 112 rests on the second member 210, ensuring positional stability of the braille pin 112; therefore, any force applied by the user's finger on the braille pin 112 while reading a display output may not cause the second member 210 to rotate back and make the braille pin 112 recede. Various intermediate positions 506C, 506D of the second member 210 within the slot 302 while the second member 210 slides from the second position 506A to the first position 506B, are illustrated in FIG. 5A.

[0083] As used herein, the term "display output" may refer to an intended braille character, symbol, word, or textual content that is to be presented to a user through the tactile interface of the braille display cell 100. The display output may correspond to digital information received from an external source such as a computer, mobile device, or electronic text reader, which is processed and converted into corresponding braille dot patterns for tactile presentation. The display output may specify which braille pins 112 within the braille display cell 100 shall be in the raised position and which shall be in the lowered position to form the desired braille characters. For example, a display output may include instructions indicating that specific braille pins 112 within the braille display cell 100 shall be raised to represent a particular letter, number, punctuation mark, or other braille symbols according to braille encoding schemes.

[0084] Referring to FIG. 5B, a diagram that illustrates a geometric relation of the second member 210 with the slot 302 is shown, in accordance with various embodiments of the present disclosure. FIG. 5B is explained in conjunction with FIGs. 1A-5A.

[0085] As illustrated in FIG. 5B, the eccentricity e of the second member 210, a diameter 0d of the second member 210, a width w and a length I of the slot 302, a distance .s from the rotational axis 504 of the rotary actuator 114 to a right edge 508 of the slot 302, and a distance g from the rotational axis 504 of the rotary actuator 114 to the first guide wall 106 are configured in a way that the geometric parameters allow the second member 210 to only rotate up to a first maximum angle a in the first rotational direction beyond the vertical axis of the braille pin 112 to reach the first position 506B where the second member 210 stays rotationally stable and the braille pin 112 is in the raised position 502D, and rotate only up to a second maximum angle in the second rotational direction beyond the vertical axis of the braille pin 112 to reach the second position 506A where the second member 210 stays rotationally stable and the braille pin 112 is in the lowered position 502A. The first maximum angle a is defined as the angular limit of rotation in the clockwise direction (when viewed from the crankshaft 204 end) that positions the second member 210 at the first position 506B within the slot 302. The second maximum angle is defined as the angular limit of rotation in the counterclockwise direction that positions the second member 210 at the second position 506A within the slot 302. The vertical axis of the braille pin 112 is defined as the longitudinal centerline of the braille pin 112 that extends perpendicular to the reading surface 102 and serves as the reference axis for measuring rotational angles of the second member 210.

[0086] In various examples, the braille pin 112 is raised to a height sufficient for the tip 304 to be easily discernible to the user, ensuring optimal tactile feedback and improved readability. The height of the braille pin 112 is defined as the vertical distance that the tip 304 extends above the reading surface 102 when the braille pin 112 is in the raised position 502D, measured from a top surface of the readingsurface 102 to the highest point of the tip 304. The braille pin 112 is configured to be raised with a lifting force adequate to overcome resistance from a user’s fingertip on the reading surface 102, thereby enabling clear tactile perception of the upward movement of the tip 304 during braille character refresh in the braille display cell 100. The lifting force corresponds to the vertical force exerted by the rotary actuator 114 through the crankshaft 206 mechanism to overcome any frictional resistance, gravitational forces, and any external pressure applied by the user's finger during tactile reading.

[0087] In some scenarios, the rotary actuator 114 can be limited by the torque the rotary actuator 114 can generate; therefore, the eccentricity e of the second member 210 is maintained at a minimal value to achieve a higher lifting force on the braille pin 112. The maximum height to which the braille pin 112 can be lifted corresponds to 2e, which occurs when the second member 210 is positioned at an angular displacement a = 0°. At this angular position, any downward force applied by a user’s finger on the tip 304 may induce reverse torque on the second member 210 through the braille pin 112 and the slot 302 interface, potentially causing the braille pin 112 to retract into the respective hole 104. The term reverse torque refers to a rotational moment generated in a direction opposite to the intended rotation of the rotary actuator 114 due to downward pressure transmitted through the braille pin 112. In the present embodiment, the maximum angular displacement a may be set within a configured range (for example, 10° to 15°) to prevent reverse rotation and maintain positional stability of the braille pin 112. The optimal value of the angle a can be determined experimentally through trial and error. The distance 5 from the rotational axis 504 of the rotary actuator 114 to the right edge 508 of the slot 302 is therefore defined by the relationship 5 = d / 2 + e. sin(a). The geometric and dimensional parameters are configured such that the rotation of the second member 210 is limited to the first maximum angle a in the first rotational direction and a corresponding second maximum angle (not shown) in the opposite direction, thereby ensuring stable positioning of the braille pin 112 in both terminal positions 502A, 502D.

[0088] In various embodiments, the first maximum angle a and the second maximum angle are determined by geometric constraints imposed by the interaction between multiple geometric and dimensional parameters including at least one of the eccentricity e of the second member 210, a diameter or a size of the second member 210, a size of the slot 302, a shape of the slot 302, a position of the slot 302, or a position of the first guide wall 106.

[0089] In an example, the eccentricity e of the second member 210 may influence the first and second maximum angles by defining a radial offset from the rotational axis 504, where a larger eccentricity e results in a greater circular path radius and correspondingly affects the angular limits defined by the first and second maximum angles. The relationship between the eccentricity e and the first maximum angle a may be expressed as: the distance .s from the rotational axis 504to the right edge 508 of the slot 302 is defined by s = + e • sin (<z), where d is the diameter of the second member 210.

[0090] In various embodiments, the size of the slot 302, specifically the width w and length I of the slot 302, constrains the horizontal sliding movement range of the second member 210 during rotation. The width w may be configured to be equal or greater than the diameter d of the second member 210 with sufficient sliding tolerance. The length I of the slot 302 may be configured to be at least I = d + e. { 1 + sin(a)}. Any value of w and 1 smaller than this may restrict the full range of sliding motion of the second member 210 inside the slot 302 and thereby influence the first and the second maximum angles.

[0091] In various embodiments, the shape of the slot 302 affects the contact interface between the second member 210 and the slot walls. For example, a rectangular slot shape may provide uniform contact surfaces and predictable constraint forces, while alternative shapes such as curved or tapered slots may modify the force distribution and affect the first and second maximum angles at which rotational locking occurs.

[0092] In various embodiments, the position of the slot 302, more specifically, the position of the right edge 508 of the slot 302 relative to the rotational axis 504 is determined by the eccentricity e, the diameter d of the second member 210 and the first maximum angle a. For a determined value of the first maximum angle a, the distance 5 from the right edge 508 of the slot 302 to the rotational axis 504 is determined by the relation s = d / 2 + e. sin(a).

[0093] In various embodiments, the position of the first guide wall 106, specifically the distance g from the rotational axis 504 to the first guide wall 106, may establish a physical constraint that limits the rotational range of the second member 210. The distance g from the rotational axis 504 to the first guide wall 106 is limited to the sum of distance 5 from the right edge 508 of the slot 302 to the rotational axis 504 and the thickness of the braille pin 112 beyond the right edge 508 of the slot 302.

[0094] In certain embodiments, abrupt stopping of the crankshaft 206 after reaching the first position 506B or the second position 506A may cause debounce, resulting in the crankshaft 206 resting at positions slightly offset from the intended first position 506B or the second position 506A. The term debounce refers to an undesired bounce back or reflection that occurs when the second member 210 impacts edge of the slot 302 at the maximum positions (e.g., the first position 506B or the second position 506A), potentially causing the second member 210 to remain at an intermediate position instead of the precise terminal positions 506A, 506B. To correct this condition, a small voltage pulse may be applied to the rotary actuator 114 to momentarily rotate the crankshaft 206 in the required direction, thereby ensuring accurate alignment at the designated first position 506B or the second position 506A. The small voltage pulse may be characterized as a brief electrical signal of lower amplitude and shorter duration relative to the primary actuation voltage. For example, when the crankshaft 206 stops marginally short of the raised position 502D due to mechanical rebound, a corrective voltage pulse applied in the same rotational direction (e.g., the first rotational direction) repositions the second member 210 to the exact angular position corresponding to the raised position 502D.This control approach provides precise adjustment of the first and second maximum angles, resulting in accurate and stable positioning of the braille pin 112 and ensuring consistent vertical displacement across the braille pin assemblies 110.

[0095] The braille display cell 100 described herein provides a configuration for achieving selective raising and lowering of the braille pins 112 using a reduced number of constituent components, thereby addressing limitations associated with conventional braille actuation systems. The constituent parts of the braille display cell 100 are compatible with high -volume manufacturing techniques such as, but not limited to, plastic injection molding. In the present embodiment, plastic injection molding refers to a manufacturing process in which thermoplastic material is heated to a molten state and injected under high pressure into precision molds to form the cell case 400, the guide members 118, and other structural elements with controlled dimensional tolerances. The described configuration of the braille display cell 100 enables simplified assembly, reduced part count, and lower overall manufacturing cost, while maintaining high operational reliability and consistent actuation of the braille pins 112. Furthermore, the configuration of the braille display cell 100 may eliminate the occurrence of ghost dot phenomena without requiring the use of spring elements. The term ghost dot phenomena may refer to an undesired condition in which a braille pin 112 remains fully or partially raised contrary to their intended lowered position, typically resulting from the braille pin 112 failing to fall by gravity and being frictionally held in place because of foreign debris or dust.

[0096] Referring to FIGS. 6A and 6B, diagrams that illustrate perspective views of a braille display cell 600 are shown, in accordance with another embodiment of the present disclosure. FIGS. 6A and 6B are explained in conjunction with FIGs. 1A-5B.

[0097] As illustrated in FIG. 6A, the braille display cell 600 includes a cell case 602. The cell case 602 may include or house a reading surface 604, the plurality of braille pin assemblies 110, where the braille pin 112 of each of the plurality ofbraille pin assemblies 110 is coaxially aligned with the respective hole 104 that is on the reading surface 604, and a guide wall 606 that includes protruding guide members 608 to guide the braille pin 112 to move in the longitudinal direction. The protruding guide members 608 are defined as elongated structural elements that extend perpendicular from the surface of the guide wall 606, having rectangular or trapezoidal cross-sections, positioned to create channels that constrain the movement of the braille pin 112. The guide wall 606 includes a plurality of housings 610 that houses the rotary actuator 114 of each of the plurality of braille pin assemblies 110, and forms an enclosed structure with an opening on an opposite side to the side that includes the protruding guide members 608. The enclosed structure is defined as a three-dimensional housing configuration that provides mechanical protection and positional constraint for the rotary actuators 114 while allowing access for electrical connections and mechanical coupling with the braille pin 112. In an example, the cell case 602 may be a fused single part including the reading surface 604, the guide wall 606, the protruding guide members 608, and the plurality of housings 610.

[0098] In a non-limiting example shown in FIG. 6A, the braille display cell 600 is an eight-dot braille display cell that includes eight holes on the reading surface 604, eight braille pin assemblies 110, and eight housings 610. The cell case 602 has four housings of the plurality of housings 610 on the left side and four housings of the plurality of housings 610 on the right side of a central axis of the braille display cell 600, as shown in FIG. 6A.

[0099] In an example, the braille display cell 600 is obtained by placing the braille pins 112 between the plurality of protruding guide members 608, followed by placing the rotary actuators 114 into a respective housing of the plurality of housings 610 such that the second member 210 of each rotary actuator 114 is inside the slot 302 of the corresponding braille pin 112. In an example, an assembly process of the braille display cell 600 may involve first positioning each braille pin 112 within the channels formed by adjacent protruding guide members 608, ensuring longitudinal alignment, then inserting each rotary actuator 114 into thecorresponding housing 610 while simultaneously engaging the second member 210 with the slot 302 through a sliding insertion motion.

[0100] As illustrated in FIG. 6B, the braille display cell 600 may further include a cell cover 612 placed over an opening on the opposite side of the guide wall 606, such that the plurality of braille pin assemblies 110 is enclosed within the cell case 602 and making the braille display cell 600 a closed-box assembly. In an example, the cell cover 612 may be a planar or contoured closure element that seals the opening of the cell case 602. The cell cover 612 may be secured through mechanical fasteners, snap-fit connections, or adhesive bonding to create an enclosed environment for the braille pin assemblies 110.

[0101] Referring collectively to FIGS. 6A, and 6B, in an embodiment, an eightdot braille display cell 600 is exemplified that has eight braille pin assemblies 110 and eight housings 610. The eight-dot configuration corresponds to the standard Braille cell format having two columns of four dots each, enabling representation of extended Braille character sets including mathematical and scientific symbols. Four housings 610 are positioned on the left side of a center axis of the braille display cell 600 and four housings 610 are positioned on the right side of the center axis of the braille display cell 600 in a stepped arrangement. This stepped arrangement enables the braille pins 112 of different lengths to reach the same reading surface level while maintaining coaxial alignment with their respective holes 104.

[0102] Referring to FIG. 6C, a diagram that illustrates a perspective view 614 of the braille pin assemblies 110 is shown, in accordance with another example embodiment of the present disclosure. FIG. 6C is explained in conjunction with FIGs. 1A-6B. As illustrated in FIG. 6C, the plurality of braille pin assemblies 110 includes four pairs of the braille pins 112 of varying lengths, where the second member 210 of each rotary actuator 114 is inside the slot 302 of the corresponding braille pin 112. The varying lengths are defined as different dimensional configurations of the braille pins 112, configured to accommodate a steppedarrangement of the housings 608 while ensuring that the tactile tips 304 reach the same vertical level at the reading surface 604 when the braille pins 112 are in the raised position.

[0103] Referring to FIG. 7, a diagram that illustrates a stack 700 of braille display cells used in a braille display device is shown, in accordance with an example embodiment of the present disclosure. FIG. 7 is explained in conjunction with FIGs. 1 A-6C. As illustrated in FIG. 7, a plurality of braille display cells 600 is arranged in a linear stack in the braille display device. In an example, a length of the braille display device may depend on the number of braille display cells 600 stacked. The linear stack may correspond to a sequential arrangement of the braille display cells 600 positioned end-to-end along a horizontal axis, creating a continuous reading surface that can accommodate multiple braille characters simultaneously. Each braille display cell 600 of the stack 700 may include the rotary actuator 114 that is independently operable via an external actuator driver circuit. The external actuator driver circuit may be configured to provide electrical control signals to individual rotary actuators 114 within each braille display cell 600. By selectively applying a voltage of appropriate polarity across the electrical wires 204 of each rotary actuator 114, the corresponding braille pin 112 is raised or lowered, thereby enabling the selective actuation of each braille pin 112 of each braille display cell 600 of the stack 700. Through the independent control of the rotary actuators 114 of each braille display cell 600 of the stack 700, the braille display device is configured to generate and present any desired braille characters, words, or sentences across the stacked braille display cells 600 with respect to a desired display output.

[0104] Referring to FIG. 8, a diagram that illustrates a perspective view of a braille display cell 800 is shown, in accordance with an example embodiment of the present disclosure. FIG. 8 is explained in conjunction with FIGs. 1 A-7.

[0105] As illustrated in FIG. 8, the braille display cell 800 includes a central wall 802 that includes the plurality of guide members 118 on a front surface 802Aof the central wall 802 and a back surface 802B of the central wall 802. The central wall 802 is defined as a vertical partition element that structurally divides the braille display cell 800 into front and rear sections, providing mounting surfaces for the guide members 118 and a plurality of housings 806 while maintaining structural rigidity of the overall braille display cell 800. The central wall 802 may be configured to support a reading surface 804 on a top side thereof and the plurality of housings 806, where half of the plurality of housings 806 are on a front side of the central wall 802 and the remaining half of the plurality of housings 806 are on a back side of the central wall 802. The front side of the central wall 802 corresponds to the side facing the front surface 802A, and the back side of the central wall 802 corresponds to the side facing the back surface 802B.

[0106] In a non-limiting example shown in FIG. 8, the central wall 802 supports eight housings 806, where four housings 806 are on the front side of the central wall 802 and four housings 806 are on the back side of the central wall 802. Among the four housings 806 on the front side of the central wall 802, two housings 806 are on the left (denoted as ‘L’ in FIG. 8) of the central wall 802, and the remaining two housings 806 are on the right (denoted as ‘R’ in FIG. 8) of the central wall 802. Similarly, among the four housings 806 on the back side of the central wall 802, two housings 806 are on the left of the central wall 802, and the remaining two housings 806 are on the right side of the central wall 802.

[0107] As the central wall 802 structurally partitions the braille display cell 800 into two sections, the central wall 802 enables organized placement and alignment of the plurality of braille pin assemblies 110 during construction of the braille display cell 800, thereby reducing assembly complexity and enhancing manufacturability of the entire braille display cell 800. The organized placement is defined as a systematic arrangement where braille pin assemblies 110 are positioned in predetermined locations with consistent spacing and alignment, facilitated by the guide members 118 and housings 806 integrated into the central wall 802 structure.

[0108] Referring to FIG. 9, a diagram 900 that illustrates a stack 902 of braille display cells used in a braille display device is shown, in accordance with another example embodiment of the present disclosure. FIG. 9 is explained in conjunction with FIGs. 1 A-8.

[0109] As illustrated in FIG. 9, a plurality of braille display cells 800 is arranged in a linear stack 902 to constitute the braille display device. A length of the braille display device may depend on the number of the braille display cells 800 stacked. The working principle of the braille display device is similar to the previous embodiment, where the braille pin 112 can be selectively raised or lowered by selectively applying a voltage of appropriate polarity to the corresponding rotary actuator 114. The braille display device is configured to generate and present any desired braille characters, words, or sentences across the stacked braille display cells 800 with respect to a desired display output.

[0110] Referring to FIG. 10, a diagram that illustrates a perspective view of a braille display system 1000 according to a modification of the braille display cell 100 is shown, in accordance with an example embodiment of the present disclosure. FIG. 10 is explained in conjunction with FIGs. 1A-9. In some embodiments, the braille display cell 100 may integrate a dot-sensing system configured to determine the position of the braille pin 112, indicating whether the braille pin 112 is in a raised or lowered state. The dot-sensing system may refer to an electronic feedback mechanism including switches, sensors, or other detection elements that monitor the position of the braille pin 112 and generate electrical signals corresponding to the current position of the braille pin 112 for processing by a control system.

[0111] As illustrated in FIG. 10, the braille display system 1000 according to the modification of the braille display cell 100 is different from the braille display cell 100 in that the first guide wall 106 includes a switch assembly 1002 corresponding to each braille pin 112. The switch assembly 1002 may include a first switch 1004 and a second switch 1006.

[0112] In various embodiments, the switch assembly 1002 may correspond to a switching mechanism including two switches positioned to detect a rotational position of the crankshaft 206 and thereby determine the position of the associated braille pin 112. In an example, the first switch 1004 may be above a rotational axis 1008 of the crankshaft 206, whereas the second switch 1006 may be below the rotational axis 1008 of the crankshaft 206.

[0113] In an example, the first switch 1004 may be an elastic limit switch positioned above the rotational axis 1008 of the crankshaft 206. The first switch 1004 may be configured to generate an electrical signal when contacted by a protrusion on the crankshaft 206 during the rotational movement of the rotary actuator 114 corresponding to the raising of the braille pin 112. The second switch 1006 may be another elastic limit switch positioned below the rotational axis 1008 of the crankshaft 206. The second switch 1006 may be configured to generate an electrical signal when contacted by the protrusion on the crankshaft 206 during the rotational movement of the rotary actuator 114 corresponding to the lowering of the braille pin 112. In an example, the switch assembly 1002 can have any construction that employs a spring or elastic element, which, upon contact or impact, electrically shorts two contact pads. For the sake of brevity, the description of the similar components of the braille display cell 100 is omitted.

[0114] In various embodiments, each of the first switch 1004 and the second switch 1006 may include an elastic construction that employs a spring or elastic element configured to electrically short two contact pads upon contact or impact. In an example, each of the first switch 1004 and the second switch 1006 may include a convex elastomer structure 1008 having a protruding plunger element 1010 positioned on an inner surface thereof. The convex elastomer structure 1008 may be positioned over the pair of contact pads, where pressing the convex elastomer structure 1008 from an external surface results in the protruding plunger element 1010 pressing against the contact pads, thereby electrically shorting the contact pads. The electrical shorting enables a voltage level or electrical signal applied toone contact pad to be read on the other contact pad, thereby generating a detectable electrical signal when the first switch 1004 or the second switch 1006 is actuated.

[0115] Non-limiting examples of the first and second switches 1004, 1006 may include elastic-limit switches, convex elastomer switches, silicone membrane switches, or the like. Accordingly, a sensing mechanism achieved by utilizing the first and second switches 1004, 1006, avoids the requirement of costly and complex sensor systems. The inherent elastic characteristics of the first and second switches 1004, 1006 may reduce mechanical impact noise generated when the protrusion on the crankshaft 206 comes into contact with the first and second switches 1004, 1006 from rotational velocity, thereby enabling substantially silent operation of the braille display system 1000.

[0116] Referring to FIGS. 11A and 11B, diagrams 1100A and 1100B that illustrate a switch actuation mechanism corresponding to the raised position of the braille pin 112 are shown, in accordance with an example embodiment of the present disclosure. FIGS. 11 A and 1 IB are explained in conjunction with FIGS. 1 A-10.

[0117] As illustrated in FIG. 11 A, the crankshaft 206 has a protruding arm 1102 thereon. The protruding arm 1102 (also referred to as “the protrusion”) is configured to actuate one of the first switch 1004 or the second switch 1006 of the switch assembly 1002 based on a rotation of the rotary actuator 114. For example, the protruding arm 1102 may be configured to actuate the first switch 1004 when the rotary actuator 114 rotates till the first maximum angle in the first rotational direction, lifting the braille pin 112 to the raised position. The protruding arm 1102 may correspond to an extension element that projects outward from the crankshaft 206, having sufficient length and positioning to make physical contact with the first and second switches 1004, 1006 during the rotation of the crankshaft 206. In an example, the protruding arm 1102 may correspond to a radial extension that projects outward from the crankshaft 206.

[0118] FIG. 1 IB illustrates a sectional view along A-A’ axis shown in FIG.11 A. Referring now to FG. 1 IB, the braille pin 112 is shown to have been lifted tothe raised position due to rotation of the rotary actuator 114 till the first maximum angle in the first rotational direction. As a result, the protruding arm 1102 contacts and actuates the first switch 1004 that is placed above the rotational axis 1008 of the crankshaft 206. The second switch 1006 that is placed below the rotational axis 1008 of the crankshaft 206 remains uncontacted by the protruding arm 1102. As a result, the first switch 1004 generates a first electrical signal. The first electrical signal may correspond to an electrical output produced by the first switch 1004 when the protruding arm 1102 makes physical contact with the first switch 1004. In an example, the first electrical signal may include a voltage change, a current pulse, or a digital state change that can be detected by a control circuit.

[0119] Referring to FIGS. 12A and 12B, diagrams 1200A and 1200B that illustrate a switch actuation mechanism corresponding to the lowered position of the braille pin 112 are shown, in accordance with an example embodiment of the present disclosure. FIGS. 12A and 12B are explained in conjunction with FIGS. 1A-11B.

[0120] As illustrated in FIG. 12A, the protruding arm 1102 is shown to be in contact with the second switch 1006 when the braille pin 112 is in a lowered position. The protruding arm 1102 may contact the second switch 1006 when the rotary actuator 114 rotates till the second maximum angle in the second rotational direction, lowering the braille pin 112 to the lowered position.

[0121] FIG. 12B illustrates a sectional view along B-B’ axis shown in FIG. 12A. Referring now to FG. 12B, the braille pin 112 is shown to have been lowered to the lowered position due to rotation of the rotary actuator 114 till the second maximum angle in the second rotational direction. As a result, the protruding arm 1102 contacts and actuates the second switch 1006 that is placed below the rotational axis 1008 of the crankshaft 206. The first switch 1006 that is placed above the rotational axis 1008 of the crankshaft 206 may remain uncontacted by the protruding arm 1102. As a result, the second switch 1006 generates a second electrical signal. The second electrical signal may correspond to an electrical output produced by thesecond switch 1006 when the protruding arm 1102 makes physical contact with the second switch 1006. In an example, the second electrical signal may include a voltage change, a current pulse, or a digital state change that can be detected by a control circuit.

[0122] Referring to FIG. 13, a block diagram that illustrates a closed-loop system 1300 implemented in a braille display system is shown, in accordance with an example embodiment of the present disclosure. FIG. 13 is explained in conjunction with FIGs. 1A-12B. In an example, the braille display system that implements or includes the closed-loop system 1300 can be any of the braille display cell / system 100, 600, 700, 800, 900, 1000 described herein. As illustrated in FIG. 13, the closed-loop system 1300 includes a controller 1302, the first switch 1004, the second switch 1006, the rotatory actuator 114, and a rotary actuator driver 1304. The rotatory actuator 114 may include the main body 202, the electrical wires 204, and the crankshaft 206 as described in FIGS. 2 A and 2B.

[0123] In various embodiments, the controller 1302 may be electrically coupled to the first switch 1004 and the second switch 1006. The controller 1302 may be an electronic control unit including a microprocessor, memory, input / output interfaces, and associated circuitry configured to receive signals from the first switch 1004 and the second switch 1006 and provide control commands to the rotary actuator driver 1304. The controller 1302 may be further connected to the rotary actuator driver 1304 that actuates the rotary actuator 114. The rotary actuator driver 1304 may be an electronic circuit including power switching elements, voltage regulation components, and control interfaces configured to provide electrical power of appropriate polarity and magnitude to the rotary actuator 114 (for example, via the electrical wires 204) based on commands received from the controller 1302.

[0124] In an embodiment, the controller 1302 may be configured to determine a position of the braille pin 112 that is engaged with the crankshaft 206 based on the actuation of one of the first switch 1004 or the second switch 1006. In anexample, the controller 1302 may receive the first electrical signal or the second electrical signal from the first switch 1004 or the second switch 1006, respectively, and determine whether the braille pin 112 is at the raised position or the lowered position. For example, if the controller 1302 receives the first electrical signal from the first switch 1004, the controller 1302 may determine that the braille pin 112 is at the raised position. However, if the controller 1302 receives the second electrical signal from the second switch 1006, the controller 1302 may determine that the braille pin 112 is at the lowered position. More specifically, the controller 1302 reads a binary status of the braille pin 112, whether the braille pin 112 is in the raised position or the lowered position, based on the actuation of one of the first switch 1004 or the second switch 1006, thereby making the braille display system operate as a closed feedback loop system. The binary status is defined as a two-state condition indicator where the braille pin 112 can be definitively identified as either in the raised position (corresponding to a logical "1" or "high" state) or in the lowered position (corresponding to a logical "0" or "low" state) based on which of the first switch 1004 or the second switch 1006 is actuated.

[0125] The closed loop system 1300 further implements a feedback control where the controller 1302 determines an actual position of the braille pin 112 through the first switch 1004 and the second switch 1006, and compares the determined position with a desired position corresponding to a display output. For example, the controller 1302 may receive the first electrical signal or the second electrical signal from the first switch 1004 or the second switch 1006, respectively, and determine if the braille pin 112 was operated correctly or not with respect to the display output.

[0126] In one scenario, the determined position of the braille pin 112 may be same as the desired position, indicating that the determined position of the braille pin 112 is correct with respect to the display output. In an alternate scenario, the determined position of the braille pin 112 may be different from the desired position, indicating that the determined position of the braille pin 112 is incorrect with respect to the display output. In such a scenario where the controller 1302 detectsthat the determined position of the braille pin 112 is incorrect with respect to the display output, the controller 1302 may provide a corrective signal to the rotary actuator 114 via the rotary actuator driver 1304. The corrective signal may cause the rotary actuator 114 to rotate further, thereby moving the braille pin 112 to a correct position. The corrective signal may correspond to an electrical command generated by the controller 1302 when a discrepancy is detected between the determined position and the desired position of the braille pin 112. The corrective signal may include a voltage polarity and a duration specification that causes the rotary actuator driver 1304 to apply appropriate electrical power to rotate the rotary actuator 114, thereby moving the braille pin 112 to the correct position.

[0127] FIG. 14 is a diagram that illustrates a braille display device 1400 including a stack 1402 of a plurality of braille display cells 1404, in accordance with an example embodiment of the present disclosure. The braille display device 1400 may include a housing 1406 that houses the stack 1402 of the plurality of braille display cells 1404. The braille display cells 1404 can be implemented using any of the braille display cells 100, 600, 614, 800, 1000, or the like.

[0128] In an example embodiments, each of the plurality of braille display cells 1404 may include a reading surface 1408 including a plurality of holes 1410, a guide wall 1412 coupled to the reading surface 1408, and a plurality of braille pin assemblies (e.g., any of the braille pin assemblies described for the braille display cells 100, 600, 614, 800, 1000). Each of the plurality of braille pin assemblies may include a braille pin and a corresponding rotary actuator configured to rotate to cause the braille pin to move in a longitudinal direction between a raised position and a lowered position.

[0129] While various embodiments of the disclosure have been illustrated and described, it will be clear that the disclosure is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the spirit and scope of the disclosure, as described in the claims.

[0130] A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims.

Claims

CLAIMSWe Claim:

1. A braille display cell (100), comprising: a reading surface (102) including a plurality of holes (104); a first guide wall (106) coupled to the reading surface (102); and a plurality of braille pin assemblies (110), wherein each of the plurality of braille pin assemblies (110) includes: a braille pin (112) extending in a longitudinal direction along the first guide wall (106), wherein the braille pin (112) includes a tip (304) on a first end and a slot (302) on a second end that is opposite to the first end, the braille pin (112) is coaxially aligned with a respective hole (104) of the plurality of holes (104), and the braille pin (112) is movable in the longitudinal direction through the respective hole (104); and a rotary actuator (114) that includes a crankshaft (206) engaged with the slot (302), wherein the rotary actuator (114) is configured to rotate to cause the braille pin (112) to move in the longitudinal direction.

2. The braille display cell (100) as claimed in claim 1, wherein the first guide wall (106) includes a plurality of guide members (118), and a subset of the plurality of guide members (118) blocks a transverse movement of the braille pin (112).

3. The braille display cell (100) as claimed in claim 1, wherein the crankshaft (206) includes: a first member (208) that forms a rotational shaft of the rotary actuator (114); and a second member (210) having a central axis spaced from a rotational axis of the first member (208) by an eccentricity,the second member (210) is coupled to the first member (208) at one end thereof and extends into the slot (302) at an opposite end thereof, and the crankshaft (206) is engaged with the slot (302) by the second member (210) that extends into the slot (302).

4. The braille display cell (100) as claimed in claim 3, wherein the second member (210) is detachably coupled to the first member (208).

5. The braille display cell (100) as claimed in claim 3, wherein the rotary actuator (114) is configured to rotate to cause the first member (208) to rotate, the rotation of the first member (208) causes the second member (210) engaged with the slot (302) to: follow a circular path relative to the rotational axis of the first member (208), and simultaneously slide along an inner face of the slot (302), the rotation of the first member (208) is limited to: a first maximum angle in a first rotational direction to position the second member (210) at a first position (506B) within the slot (302); and a second maximum angle in a second rotational direction to position the second member (210) at a second position (506A) within the slot (302), and the first rotational direction is opposite to the second rotational direction.

6. The braille display cell (100) as claimed in claim 5, wherein in a case the second member (210) is at the first position (506B): the braille pin (112) is at a raised position (502D), and the tip (304) of the braille pin (112) protrudes out of the respective hole (104) in the raised position (502D), and in a case the second member (210) is at the second position (506A): the braille pin (112) is at a lowered position (502A), andthe tip (304) of the braille pin (112) recedes into the respective hole (104) in the lowered position (502A).

7. The braille display cell (100) as claimed in claim 5, wherein the rotary actuator (114) is configured to rotate in the first rotational direction based on a first polarity of a voltage, and the rotary actuator (114) is configured to rotate in the second rotational direction based on a second polarity of the voltage.

8. The braille display cell (100) as claimed in claim 5, wherein the first maximum angle and the second maximum angle are based on at least one of: the eccentricity of the second member (210); a size of the slot (302), a shape of the slot (302), a position of the slot (302), and a position of the first guide wall (106).

9. The braille display cell (100) as claimed in claim 1, wherein each of the plurality of braille pin assemblies (110) further includes a housing (116) that houses the rotary actuator (114).

10. The braille display cell as claimed in claim 1, wherein the crankshaft (206) has a protrusion (1102) thereon, the first guide wall (106) includes a first switch (1004) and a second switch(1006), the first switch (1004) is above a rotational axis (1008) of the crankshaft (206), the second switch (1006) is below the rotational axis (1008) of the crankshaft (206, and the protrusion (1102) is configured to actuate one of the first switch (1004) or the second switch (1006) based on a rotation of the rotary actuator (114).

11. The braille display cell (100) as claimed in claim 10, comprising a controller (1302) coupled to the first switch (1004) and the second switch (1006), wherein the controller (1302) is configured to determine a position of the braille pin (112) based on the actuation of one of the first switch (1004) or the second switch (1006).

12. The braille display cell (100) as claimed in claim 11, wherein the controller (1302) is configured to: detect that the determined position of the braille pin (112) is incorrect with respect to a display output; and provide a corrective signal to the rotary actuator (114) based on the detection that the determined position of the braille pin (112) is incorrect, wherein the corrective signal causes the rotary actuator (114) to rotate, thereby moving the braille pin (112) to a correct position.

13. The braille display cell (100) as claimed in claim 10, wherein the first switch (1004) and the second switch (1006) correspond to elastic switches.

14. A braille display device (1400), comprising: a stack of a plurality of braille display cells (100), wherein each of the plurality of braille display cells (100) includes: a reading surface (102) including a plurality of holes (104); a first guide wall (106) coupled to the reading surface (102); and a plurality of braille pin assemblies (110), wherein each of the plurality of braille pin assemblies (110) includes: a braille pin (112) extending, in a longitudinal direction, along the first guide wall (106), wherein the braille pin (112) includes a tip (304) on a first end and a slot (302) on a second end that is opposite to the first end,the braille pin (112) is coaxially aligned with a respective hole (104) of the plurality of holes (104), and the braille pin (112) is movable, in the longitudinal direction, through the respective hole (104); and a rotary actuator (114) that includes a crankshaft (206) engaged with the slot (302), wherein the rotary actuator (114) is configured to rotate to cause the braille pin (112) to move in the longitudinal direction.

15. The braille display device (1400) as claimed in claim 14, comprising a controller(1302) electrically coupled to the rotary actuator (114), wherein the controller (1302) is configured to selectively actuate, based on a display output, the rotary actuator (114) to cause the braille pin (112) to move in the longitudinal direction.

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