JP2003122246A - Braille display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small and inexpensive braille display device by reducing the number of braille elements for controlling a braille pin also in the case of mounting a plurality of braille modules to a braille display. SOLUTION: When current switch elements SW2, SW3 (X2 and Y1) are connected, a shape memory alloy spring 6 is deformed by a normal current I1 flowing through a diode D1 to drive a braille actuator 5, and unnecessary current I2 (current flowing through SW2, a diode D3, the braille actuator 5, a diode D4, a diode D2, a shape memory alloy spring 7 and SW3 as a route) generated by connection of the current switch SW2 is prevented by the diode D3 connected in an opposite direction so as to avoid driving the other shape memory alloy spring 7, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braille display device for displaying a braille string.

[0002]

2. Description of the Related Art A conventional display device will be briefly described below with reference to the drawings. 3 is an external configuration diagram of the Braille display device, FIG. 4 is a configuration diagram of the Braille actuator, FIG. 5 is an equivalent circuit diagram of the Braille actuator, and FIG. 6 is a drive circuit diagram of the Braille display according to the prior art.

On the upper side of the braille display device 1, FIG.
As shown by, the Braille display 2 is arranged.
In this Braille display 2, a large number of Braille modules 3 are arranged in a horizontal row. In each of these braille modules 3, Braille pins 4 are arranged in a matrix of 2 × 3 as an example, and each Braille pin 4 is independently moved up and down by a braille actuator described later (arrow A in FIG. 3). Direction) can be driven.

The Braille display device 1 drives the Braille actuator to move the Braille pin 4 up and down to project the dots, form Braille in the Braille module 3 as a whole, and display the Braille text on the Braille display 2. . The visually impaired person traces the Braille display 2 of the Braille display device 1 with a finger and recognizes information such as a sentence.

Next, the Braille actuator will be described. The Braille actuator 5 has an overall configuration as shown in FIG. Braille actuator 5 in FIG.
Then, a shape memory alloy is adopted as the drive unit. The two shape memory alloy springs 6 and 7 are installed between the upper plate 9 and the lower plate 10 via the support plate 8.
In this case, the shape memory alloy spring 6 is fixed to the support plate 8 and the upper plate 9, and the shape memory alloy spring 7 is connected to the support plate 8.
It is also fixed to the lower plate 10. When a driving current is applied only to the shape memory alloy spring 6 via the terminals 11 and 12, heat is generated due to the resistance loss of the spring, the shape memory alloy spring 6 contracts due to its characteristics, and the operation of pulling up the support plate 8 is performed. 4 rises (moves in the direction of arrow B in FIG. 4), and conversely, when the shape memory alloy spring 7 is electrically heated via the terminals 12 and 13, the support plate 8 is pulled down and the braille pin 4 is lowered ( (It moves in the direction of arrow C in FIG. 4).

When the shape memory alloy springs 6 and 7 are used,
Braille actuator 5 equivalent to the basic drive circuit
The equivalent circuit of is shown in FIG. In FIG. 5, two shape descriptions
Storage alloy springs 6 and 7 have two equivalent resistances 1 in terms of an electric circuit.
Expressed as 4, 15 and the current switch element SW of the drive circuit
₁When you close (SW_TwoIs open), only equivalent resistance 14 is driven
Current flows, and current switch element SW _TwoWhen you close
(SW₁Drive current flows only to the equivalent resistance 15.
It In this way, controlling the raising and lowering of the Braille pin 4
You can

Next, a drive circuit diagram of a braille display in which current switch elements for controlling the current of the braille actuator 5 are arranged in a matrix to selectively drive the braille pins 4 in the braille modules 3. An example of the configuration will be shown. In FIG. 6, letters X and Y indicate selection signals for the Braille actuator 5. X is the column of the matrix (corresponding to the braille module; the number matches the braille module), Y is the row of the matrix (corresponding to the braille pin in the braille module. The number is required for one braille pin and two Y's) , For a total of 6 Braille pins).

The Braille actuator 5 for controlling one Braille pin 4 is composed of two equivalent resistances, that is, shape memory alloy springs 6 and 7. As a selection example, when a drive current is passed through the shape memory alloy spring 6 to raise (or lower) the Braille pin 4, a controller (not shown) outputs the selection signals X ₁ and Y ₃ to set SW ₃₀ and SW ₁₀ . Just drive it so that it closes. Conversely, when a drive current is passed through the shape memory alloy spring 7 to lower (or raise) the Braille pin, a controller (not shown) selects a selection signal X ₁ ,
Y ₄ may be output and SW ₃₀ and SW ₂₀ may be driven so as to be closed. By controlling a large number of current switching elements arranged in a matrix with the selection signals X and Y,
One of the braille modules 5 can drive one braille pin 4.

[0009]

However, as an example, when the number of rows of the matrix is m = 6 (up to Y ₁₂ ) and the number of columns is n (up to X _n ), all of the current switching elements are required. The number is 13 × n). To give a specific example, when n = 12 (the number of braille modules is 12 columns), the number of switch elements is 156, which is a great obstacle to downsizing and cost reduction of the braille display device 1. is there. Like this
In the braille display device 1 according to the related art, when the number of the braille pins 4 and the number of the braille modules 3 displayed on the braille display 2 increase, the number of current switch elements for controlling the braille pins 4 increases dramatically, and the braille display device 1 increases. There is a problem that it is difficult to reduce the size and cost.

As a measure against this problem, it can be considered that a large number of current switch elements are integrated into one package to reduce the mounting area. However, when the Braille actuator 5 is composed of the shape memory alloy springs 6 and 7 as described above, for example, current heating needs to be performed. In that case, the current value required for heat generation is generally When it exceeds several A (because the equivalent resistance is low), the loss of the current switch element itself becomes large, and the current switch element must be sized to some extent due to heat radiation. Therefore,
There is a problem that it is difficult to realize an IC.

The present invention has been made in view of the above points, and it is an object of the present invention to solve the above problems and to reduce the number of switch elements for controlling a Braille pin even when a plurality of Braille modules are mounted on a Braille display. An object of the present invention is to provide a braille display device that is reduced in size and small in size and inexpensive.

[0012]

In order to solve the above-mentioned problems, the invention as set forth in claim 1 is provided with a Braille actuator for driving two driving units to move the Braille pins up and down, and a plurality of the Braille actuators. A braille module for projecting braille, a braille display for arranging the braille modules in a plurality of rows to expose the braille string, and a drive current to the drive part of the braille actuator to expose the braille string to the braille display. In a braille display device including a braille display driving circuit that drives the braille pins up and down so that the braille pin is driven, the braille display driving circuit is connected to two current switch elements X connected to a power supply side and a ground side. One current switch element Y and the two current switch elements X are connected to the anode side, respectively. Two diodes, and two Braille actuator drive units, one end of which is connected to each of the cathode sides of the two diodes, and the other ends of which are both connected to the one current switch element Y side. 1
Is a circuit in which one unit for driving the Braille actuator is formed, and a plurality of units are formed by arranging the current switch elements X and Y in a matrix. One current switch element X and one current switch element A current flowing in the forward direction when Y and Y are closed drives the Braille pin up and down by a driving unit connected to the diode, and a current flows through a driving unit connected to another diode connected to the same current switch X. Is prevented.

The invention described in claim 2 is the same as claim 1
The braille display device according to claim 1, further comprising a controller that opens and closes the current switch elements X and Y to control the drive of the braille actuator, and the controller displays past display data when updating and displaying the braille display. It is characterized by comprising means for comparing display data to be updated, extraction means for extracting only display data that differs according to the comparison result, and control means for driving a Braille actuator related to the extracted display data.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to FIGS. FIG. 1 is a drive circuit diagram of the Braille display device of the present embodiment. Note that FIG.
The external structure of the braille display device shown in FIG. 4 and the structure of the braille actuator shown in FIG. 4 are the same as those of the conventional art, and thus detailed description thereof is omitted. Also, as in FIG. 6, the letters X and Y are
The selection signal of the Braille actuator 5 is shown. X is a column of the matrix (corresponding to the braille module), Y is a row of the matrix (corresponding to the braille pins in the braille module: For example, the six braille pins 4 in the braille module 3 shown in FIG. 3 are Y ₁
It is connected to either a to Y _6. ).

A portion surrounded by a dotted line is one Braille actuator 5, and the drive unit of the present invention provided in the Braille actuator 5 corresponds to the shape memory alloy springs 6 and 7. When operating one Braille actuator 5 from a plurality of Braille modules 3, as a selection example, when a driving current is passed through the shape memory alloy spring 6 to raise (or lower) the Braille pin, it is not shown. It suffices to drive the selection signals X ₂ and Y ₁ from the upper braille display control device (controller), that is, to close SW ₂ and SW ₃ . On the contrary, when the Braille pin is lowered (or raised), the selection signals X ₁ and Y ₁ are driven, that is, SW ₁ and SW ₃ are closed, and a drive current is selectively passed to the shape memory alloy spring 7. be able to.

Next, the current flow to the selected Braille actuator 5 and the function of the diode element installed between the Braille actuator 5 and the power source will be described. FIG. 2 is a partially extracted drive circuit diagram of the Braille actuator, and is for explaining the current flow in the Braille actuators 5 arranged in a matrix in FIG. When a drive current is passed only through the shape memory alloy spring 6 of the braille actuator 5 on the upper side of FIG. 2, the selection signals X ₂ and Y ₁ are driven by a higher-order controller (not shown), and SW ₂ and SW
Close ₃ .

In this case, the current path of the normal current I ₁ is S
It flows through W ₂ , the diode D ₁ , and the shape memory alloy spring 6, and flows through SW ₃ to the ground. Here, assuming that the diode D ₄ is not provided, an unnecessary current I ₂ is generated,
Other non-selected Braille actuators (see FIG.
An electric current flows into the shape memory alloy spring 7 via the Braille actuator 5) on the lower side, and as a result, both shape memory alloy springs 6 and 7 are driven, so that the Braille pin 4 is moved up and down. Out of control.

Therefore, in order to prevent the unnecessary current I ₂ ,
A diode D ₄ is arranged between the power supply side and the Braille actuator 5 on the lower side. In this way, the diode D
_4, it is possible to block the unnecessary current I ₂ flowing through the Braille actuator 5 on the lower side, and the situation in which the raising / lowering of the Braille pin 4 cannot be controlled does not occur.

Similarly, only the shape memory alloy spring 7 is used.
When a drive current is applied to the ₁And Y₁Illustrated
Driven by an upper controller₁And S
W_ThreeClose. In this case, the normal current (not shown)
The route is SW₁, Diode D_Two， Shape memory alloy spring
It flows through 7 and flows through SW3 to the ground. And
Diode D_ThreeAssuming that there is no
Not via Braille actuator 5 (SW in Figure 2
₁, Lower Braille actuator 5, shape memory alloy spring
6) and an unnecessary current (not shown) causes a shape memory alloy spring 6
Flow into the springs, resulting in both shape memory alloy springs 6,
7 will be driven, and raising and lowering of the Braille pin 4 cannot be controlled.
Become.

Therefore, in order to prevent unnecessary current, a diode D is provided between the power supply side and the lower Braille actuator 5.
₃ are arranged. In this way, the diode D ₃
Thus, the unnecessary current can be blocked, and the situation that the raising / lowering of the Braille pin 4 cannot be controlled does not occur.

From this relationship, as shown in FIG.
A diode is placed for every braille actuator. As is apparent from FIG. 1, the anode side of the diode is connected to the side of the current switch element X to which power is supplied, and the cathode side of the diode is connected to the side of the Braille actuator. By doing so, it becomes possible to prevent a situation in which an unnecessary current flows into all Braille actuators.

As described above, according to the present system, the number of switch elements arranged in a matrix is 6 rows (up to Y ₆ ) and n columns as shown in FIG. 1 (conventional in FIG. 6). The total number of switch elements used under the same conditions as the configuration diagram) is n + 6. As a specific example, when n = 12 (when the number of Braille modules is 12 columns), the number of switch elements is 1.
In contrast, the number is 8 in the conventional configuration (the same number of modules and the same number of braille pins), which is 156, and the number of current switching elements can be significantly reduced. As described above, the number of current switching elements can be reduced by arranging the diode elements having unidirectional current flow between the Braille actuators arranged in a matrix and the power source.

When the Braille actuator 5 is the shape memory alloy springs 6 and 7 as in this embodiment, it has a latching characteristic. This latching characteristic means that once the current is passed through the shape memory alloy springs 6 and 7 to raise or lower the braille pin 4, the braille pin 4 must be supplied with no new current.
Is a characteristic that remains in the same position. In this case, when updating the display data of the braille display 2,
The controller (not shown) compares the past display data with the display data to be updated, extracts only the different display data, and controls the Braille actuator.
For this reason, a new braille string is displayed by driving only the braille pin that needs to be changed, so that unnecessary drive current to the braille actuator can be suppressed and the power consumption of the braille display device can be reduced. .

According to the present invention, the switch elements arranged in a matrix for controlling the drive current to the plurality of Braille modules and the Braille pins, and the unnecessary current from other than the selected Braille pins configured in the matrix. In order to prevent this, a diode element was installed between the Braille actuator and the power supply. With such a configuration, it is possible to reduce the number of switch elements required to control the drive current, and it is possible to configure a small-sized and inexpensive Braille display device.

In the above-mentioned configuration, for example, the braille actuator selected from the power supply paths other than the selection arranged in a matrix for the two shape memory alloy springs constituting the braille actuator without installing switch elements respectively. It is possible to prevent the flow of current into the Braille actuator (unnecessary current), and eventually it is possible to reduce the number of switch elements for controlling the current to the Braille actuator. This makes it possible to obtain a small and inexpensive Braille display device.

[0026]

As described above, according to the present invention, even when a plurality of Braille modules are mounted on a Braille display, the number of switch elements for controlling the Braille pins is reduced, and a small and inexpensive Braille display device is provided. You can

[Brief description of drawings]

FIG. 1 is a driving circuit diagram of a braille display device according to an exemplary embodiment of the present invention.

FIG. 2 is a partially extracted drive circuit diagram of a Braille actuator.

FIG. 3 is an external configuration diagram of a braille display device.

FIG. 4 is a configuration diagram of a Braille actuator.

FIG. 5 is an equivalent circuit diagram of a Braille actuator.

FIG. 6 is a driving circuit diagram of a Braille display device according to the related art.

[Explanation of symbols] 1 Braille display device 2 Braille display 3 Braille module 4 Braille pins 5 Braille actuator 6,7 Shape memory alloy spring 8 Support plate 9 Upper plate 10 Lower plate 11, 12, 13 terminals 14,15 equivalent circuit SW1, SW2 Current switch element D1, D2, D3, D4 diode I1 normal current I2 Unnecessary current SW10, SW20, SW30 Current switch element

Claims (2)

[Claims] 1. A Braille actuator that drives two driving units to move a Braille pin up and down, a Braille module that includes a plurality of the Braille actuators, and a Braille module that projects Braille; A Braille display for displaying, a drive current is supplied to the drive unit of the Braille actuator,
A braille display driving circuit that drives the braille pins up and down so as to display a braille string on the braille display, and the braille display driving circuit includes two currents connected to a power supply side. Switch element X, one current switch element Y connected to the ground side, two diodes whose anode side is connected to each of the two current switch elements X side, and cathode of the two diodes One unit for driving one Braille actuator is formed by the drive units of two Braille actuators, one end of which is connected to each of the two sides, and the other ends of which are both connected to the side of the one current switch element Y. , A circuit in which a plurality of units are formed by arranging the current switch elements X and Y in a matrix, and one current switch Element X and one current switching element Y
When the and are closed, the Braille pin is driven up and down by the drive unit connected to the diode through which a current flows in the forward direction, and the current flows through the drive unit connected to another diode connected to the same current switch X. Braille display device characterized by being prevented. 2. The braille display device according to claim 1, further comprising a controller that opens and closes the current switch elements X and Y to control the drive of the braille actuator, and the controller updates and displays the braille display. In this case, it is provided with a means for comparing the past display data and the display data to be updated, an extracting means for extracting only display data that differs according to the comparison result, and a control means for driving the Braille actuator related to the extracted display data. A braille display device characterized by the above.