JP2009288757A - Braille display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and light-weight Braille display device which moves a tactile pin by vibration of a circular piezolectric element disposed below the tactile pin, and allows the tactile pins to be freely arranged, consequently permits development of a multiple line Braille display device, a Braille display device for bank ATM, a surface display device and the like. <P>SOLUTION: A shaft 12 is vertically installed in the piezoelectric element 11, an actuator in which a moving element 14 is installed across the shaft 12 is created, and voltages are intermittently applied to the piezoelectric element 11 to vibrate. An inertial force becomes larger than a friction force when a vibration speed is high, and a friction force becomes smaller than an inertial force when a vibration speed is low, and the moving element 14 moves on the shaft 12 as a result. The tactile pin 15 for Braille is connected to the moving element 14 to display Braille. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention uses a linear drive mechanism using biased PWM control of a piezoelectric element in order to realize an ultra-small braille display device.

Conventional Braille display devices using a piezoelectric element mainly use a warp of the piezoelectric element to lift the tactile pin (see, for example, Patent Document 1).
Hereinafter, a conventional braille display device will be described with reference to FIG.
Patent Publication 2007-71977 (3rd page, FIG. 1) The conventional braille display device utilizes the property that the piezoelectric element 7 is warped by applying a high voltage of about 200 V from the electrode 202 to the end of the bimorph type piezoelectric element 7. Since the piezoelectric element 7 has a warping direction determined by the polarity of the applied voltage, the piezoelectric element 7 is touched when it is warped in the direction of pushing up the tactile pin 6 disposed in contact with the end opposite to the end to which the voltage is applied. The knowledge pin protrudes from the housing 5 and is displayed as Braille.

In the conventional technology, the displacement per unit dimension of the warp of the piezoelectric element is very small. Therefore, in order to secure a displacement amount of about 0.5 mm of the tactile pin that can be perceived by the visually impaired, The length is required to be about 50 mm, which prevents the braille display device from being reduced in size and weight.
As shown in FIG. 1, since the piezoelectric element and the tactile pin are arranged in an orthogonal shape, it is necessary to arrange the piezoelectric element in the depth direction with respect to the pin in order to display the Braille. When trying to create a display device, the depth becomes very large, which also makes it difficult to develop a small and light Braille display device.

In addition, since the displacement of the piezoelectric element changes with time and the position of the piezoelectric element when it is not energized is unstable, a tactile pin may be pushed out without applying a voltage. Therefore, it is necessary to apply a negative voltage to the pins that are not displayed, and eventually, either a positive or negative voltage is applied to all the piezoelectric elements, and once the Braille display device is turned on, even if the Braille display is not displayed, There was a problem of constantly consuming power. This was a problem in creating a portable Braille display device.

When a voltage is applied to the disk-shaped piezoelectric element, the central portion of the disk is deformed to be concave or convex depending on the direction of the applied voltage. By repeating this charge intermittently, using the fact that the moving element fitted on the axis vertically arranged in the center of the piezoelectric element moves by vibration, braille display is performed by a tactile pin interlocked with the moving element. .

Piezoelectric elements have a difference in the speed of movement when charged and the speed of movement when opened, and due to the difference in speed of movement, the slider fitted on the shaft moves in either direction on the shaft due to the balance between frictional force and inertial force. It is decided whether to move. In other words, when the moving speed is fast, the inertial force is stronger than the frictional force and acts on the mover, and when the moving speed is slow, the frictional force is stronger than the inertial force and acts on the mover. Use to determine the direction of movement of the slider.

In order to move the moving element in a target direction, an electronic circuit that intermittently applies a positive or negative voltage to the piezoelectric element is created. The electronic circuit receives a Braille display signal and applies a voltage to a predetermined piezoelectric element in order to display the target Braille.

In order to instruct what kind of braille to display on the electronic circuit integrated with the braille display device, driver software that extracts the character string on the display screen of the mobile phone / personal computer and sends the data is created. The character string extracted by this driver software is converted into Braille data by the braille translation engine, and the target Braille display is performed.

Unlike the conventional Braille display device, the Braille display device according to the present invention is a system in which the tactile pin is moved up and down by the vibration of a circular piezoelectric element disposed below the tactile pin. Compared to the above, it is possible to reduce the size and weight significantly. In addition, because tactile pins can be freely arranged, which was not possible with conventional methods, it is possible to develop multi-line braille display devices, braille display devices at bank ATMs, surface display devices, etc. is there. This is very effective as a means for transmitting information to the visually impaired.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 shows an external view of a braille cell to which the present invention is applied, and FIGS. 3 and 4 show an outline of the operation.

A carbon shaft 12 is bonded to the central portion of the disk-type piezoelectric element 11, and a movable element 14 sandwiches the shaft 12. The shaft 12 is fixed by a bearing 13. The mover 14 is made of an elastic body and holds the shaft 2 with a predetermined strength. A tactile pin 15 is connected to the upper portion of the moving element 14 and moves up and down together with the moving element 14. When the tactile pin 15 comes out of the housing 16, braille is displayed.

The braille display control board and the braille display device are connected by an electric wire 17, and when a voltage is applied to the piezoelectric element 11, the central portion is raised or depressed depending on the direction of the voltage. When the voltage is released, the piezoelectric element 17 returns to a flat state before charging. Since the speed of uplift / depression at the time of charging is different from the speed at the time of return to flatness, when operating at high speed, the movable element 14 cannot follow the movement of the shaft 12 due to the law of inertia. Deviation occurs in the positional relationship of the shaft 12. When operating at a low speed, the moving element 14 and the shaft 12 move as a unit by the frictional force of the moving element 14. Utilizing this principle, the piezoelectric element 11 is intermittently charged, so that the movable element 14 continuously moves on the shaft 12, whereby the tactile pin 15 that moves integrally with the movable element 14 moves up and down. And display braille.

FIG. 3 shows a state where the tactile pin 15 is lowered, and FIG. 4 shows a state where the tactile pin is raised.

Conventional braille display External view of the braille display of the present invention Principle of operation of Braille display of the present invention (when the tactile pin is lowered) Principle of operation of Braille display of the present invention (when the tactile pin is raised)

Explanation of symbols

11 piezoelectric elements, 12 shafts, 13 bearings, 14 sliders, 15 tactile pins, 16 housings

Claims (3)

Using vibration generated by intermittently applying a voltage to a piezoelectric element, Braille is displayed by using the movement of a moving element fitted on a shaft connected to the piezoelectric element by vibration. Braille display device for the purpose. An electronic circuit for controlling each of the tactile pins of the Braille display device according to [Claim 1] to drive and display a target Braille. Driver software that extracts a character string to be displayed in Braille from character information displayed on a display screen of a mobile phone / personal computer connected to the electronic circuit of [Claim 2], and sends the character string to a Braille display device.

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