JP2000112339A - Braille display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a braille display device which is capable of stabilizing the motion of a movable member that acts by a shape memory alloy, which is easy to be miniaturized as a whole, and which enables a suitable operation performance to be obtained. SOLUTION: A plurality of openings 10a are formed on the panel of a housing 10 and constituted in a manner that the top 11a of the movable members 11 attached inside is retractable. A bias spring 14 is inserted into the upper insertion part 11A of the movable members 11, and a shape memory alloy spring 15 is inserted into the lower insertion part 11B of the movable members 11.

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, and more particularly to a structure of a Braille display device driven by using a shape memory alloy.

[0002]

2. Description of the Related Art Conventionally, a braille display device in which a plurality of movable members are constructed so as to be able to protrude and retract from an opening of a case body, and each of the movable members is constructed so as to be driven in and out by deformation accompanying a phase transformation of a shape memory alloy. Has been proposed. In each of these Braille display devices, a plurality of movable mechanisms each combining a shape memory alloy and a display cup are arranged, and are configured to protrude and retract from an opening on the front surface of a case body. The shape memory alloys include those having a simple structure such as a rod shape and those formed as a coil-shaped or bent spring.

[0003] For example, in Japanese Patent Application Laid-Open No. 61-166580, a display cup is arranged inside an opening of a case body, and a portion arranged just inside the opening so as not to escape outside from the opening. A coil-shaped shape memory alloy spring is disposed on the bottom of the display cup having the collar formed thereon so as to push up the display cup from below. The shape memory alloy spring receives heat from the heat transducer in contact with the lower end, and is heated and stretched so that the top of the display cup projects from the opening.

[0004]

However, in the above-mentioned conventional Braille display device, although the basic structure is disclosed, the operation performance when actually assembled as a Braille display device is improved to obtain a precise operation. There is no specific structure proposal for it. In particular, in the structure disclosed in the above publication, since the display cup is merely placed on the upper end of the shape memory alloy spring, there is a concern that the display cup is not stable and erroneous operation or malfunction is likely to occur. When a plurality of display cups are arranged as a Braille device, it is necessary to form a wall surface between adjacent display cups. Such a structure is disclosed in Japanese Patent Application Laid-Open No. 62-249182. Although described, it increases the volume of the device and hinders miniaturization.

Accordingly, the present invention has been made to solve the above-mentioned problems, and has as its object to stabilize the operation of a movable member operated by a shape memory alloy, and to make it easy to reduce the size as a whole. An object of the present invention is to realize a braille display device capable of obtaining suitable operation performance.

[0006]

Means taken by the present invention for solving the above-mentioned problems include a plurality of movable members which are configured to be able to protrude and retract from an opening formed in a board surface, and a predetermined temperature or temperature range. A plurality of coil-shaped shape memory alloy springs that generate a predetermined shape restoring force when the reference temperature is higher or lower than the reference temperature and cause each of the movable members to move in and out, and heat and heat the shape memory alloy spring. And / or a temperature control means for cooling, wherein the movable member has an engaging portion that penetrates the shape memory alloy spring and engages the shape memory alloy spring in the axial direction. It is characterized by having.

According to this means, the movable member is inserted into the shape memory alloy spring, and is provided with the engaging portion which engages with the shape memory alloy spring in the axial direction, so that the shape memory alloy spring is engaged. Since the movable member can be driven by acting on the movable member through the portion, and the shape memory alloy spring can be supported by the movable member,
Although it is a simple structure, it can perform stable operation, and it is not necessary to provide a support portion that supports from the periphery, such as a partition that supports and stores the shape memory alloy spring,
The size of the device can be reduced.

[0008] In the first aspect, it is preferable that the movable member has an outer diameter substantially equal to a protruding / retracting direction in a portion arranged near the inside and outside of the opening. Since the movable member has an outer diameter in the vicinity of the opening that is substantially equal to the retracting direction, malfunction or malfunction due to the movable member being caught in the opening can be prevented, and the movable member can be reliably operated. Can be done.

In the first or second aspect, the movable member includes the shape memory alloy spring and a coil-shaped auxiliary spring that engages the engaging portion from the side opposite to the shape memory alloy spring. Preferably, it is inserted in the axial direction.
By using the auxiliary spring, the movable member can be operated in one direction by using the one-way deformation at the time of phase transformation of the shape memory alloy spring, and can be returned to the original position by using the elastic force of the auxiliary spring.

Preferably, one of the shape memory alloy spring and the auxiliary spring is engaged inside an opening edge of the opening. Since one of the shape memory alloy spring and the auxiliary spring is engaged inside the opening edge, the shape memory is provided without specially providing a support portion for operating the movable member with respect to the case body. The alloy spring or the auxiliary spring can act on the movable member.

Preferably, the coil radius of the shape memory alloy spring is smaller than the coil radius of the auxiliary spring. Since the distance between a plurality of adjacent shape memory alloy springs can be increased by reducing the diameter of the shape memory alloy spring, the thermal effect between adjacent shape memory alloy springs can be reduced without providing a partition wall or the like. In addition, by making the diameter of the auxiliary spring large, the operation of the movable member can be stabilized without a sufficient support structure.

In the fifth aspect, the movable member is provided with a first insertion portion through which the shape memory alloy spring is inserted and a second insertion portion through which the auxiliary spring is inserted. Is preferably smaller than the outer diameter of the second insertion portion. Since the outer diameters of the first and second insertion portions of the movable member are formed according to the coil diameter of the shape memory alloy spring and the coil diameter of the auxiliary spring, a pivotal support state between both springs and the movable member is provided. Can be stabilized.

Next, a plurality of movable members configured to be able to protrude and retract from an opening formed in the board surface, and a predetermined shape restoring force when the temperature exceeds or falls below a predetermined temperature or temperature range as a reference temperature. And a plurality of coil-shaped shape memory alloy springs for causing each of the movable members to protrude and retract, and a power supply unit for supplying a current to the shape memory alloy springs for heating the shape memory alloy springs. A terminal member is provided which comes into contact with the elastic member while receiving the elastic force of the elastic member, and is electrically connected to the shape memory alloy spring, and power is supplied from the terminal member to the shape memory alloy spring.

According to this means, a terminal member is provided which is in contact with the shape memory alloy spring, and power is supplied to the shape memory alloy spring via the terminal member which receives elastic force from the shape memory alloy spring. Therefore, the contact portion between the terminal member and the shape memory alloy spring is made of a material or a contact structure corresponding to the material of the shape memory alloy spring, so that even if they are just in contact, the shape is based on the elastic force. Since the conductive connection with the memory alloy spring can be ensured and the contact property can be improved, a highly reliable actuator can be configured. Further, the simple structure does not hinder miniaturization and does not significantly increase the manufacturing cost.

According to a seventh aspect of the present invention, both a contact portion of the shape memory alloy spring with the terminal member and a surface portion of the terminal member contacting the contact portion are made of a material having good electrical contact properties. Is preferred. In general, since the shape memory alloy spring is inferior in electric contact property, power supply to the shape memory alloy spring can be performed by forming both the contact portion of the shape memory alloy spring and the surface of the terminal member with a material having good electric contact property. Reliability can be improved. In this case, since the contact between the terminal member and the shape memory alloy spring is made by a material having good electrical contact properties, the conductive connection between them can be further improved.

Here, it is preferable that the material is formed by gold plating. Since both the surface portion of the terminal member and the contact portion of the shape memory alloy spring are made of gold plating, a stable and good conductive connection can be obtained.
Further, it is preferable that the shape memory alloy spring and the terminal member are fixed in a conductive state. By fixing the shape memory alloy spring and the terminal member by welding or conductive paste, etc., it is possible to secure more reliable conductive connection, and the elastic force of the shape memory alloy spring is applied to the fixing portion. The durability or reliability of the fixing portion is also high.

Further, a movable member configured to be able to protrude and retract from an opening formed in the board surface, and generates a predetermined shape restoring force when the temperature exceeds or falls below a predetermined temperature or temperature range as a reference temperature. A shape memory alloy spring for moving the movable member up and down, and a temperature control means for heating and / or cooling the shape memory alloy spring, wherein the temperature control means has a thermoelectric element;
The heat generating part and / or the heat absorbing part of the thermoelectric element heats and / or cools the shape memory alloy spring.

According to this means, since the temperature of the shape memory alloy spring is controlled by using a thermoelectric element as the temperature control means, the heating or cooling can be accurately performed by the electric energy. It does not hinder miniaturization.

According to a ninth aspect, the temperature control means includes:
It is preferable that the thermoelectric element is configured to heat and cool the shape memory alloy according to the temperature of the shape memory alloy spring. The configuration is such that both heating and cooling of the shape memory alloy spring can be performed by the thermoelectric element, so that quick temperature control is possible and the response of the actuator can be improved.

Any one of claims 1 to 10
In the item, it is preferable that a temperature detecting means for detecting a temperature of the shape memory alloy spring is provided, and an electric or thermal control amount for the shape memory alloy spring is adjusted based on a temperature detected by the temperature detecting means. According to this means,
By providing the temperature detecting means, the temperature of the shape memory alloy spring can be controlled more precisely. In this case, the temperature can be detected based on the resistance value of the shape memory alloy spring itself.

Any one of claims 1 to 11
In the paragraph, a control command means for controlling the plurality of movable members, and a drive signal generation for generating a drive signal for heating or cooling the shape memory alloy spring based on a drive command received from the control command means It is preferable to provide means.

In a twelfth aspect of the present invention, the drive signal generating means is controlled by the control command means to set a standby temperature set to a value between a normal temperature and the reference temperature during a drive suspension period or before the start of drive. Preferably, the shape memory alloy spring is configured to perform heating or cooling in advance. By heating or cooling in advance from the normal temperature to the standby temperature, the shape memory alloy spring can be quickly driven.

[0023] In the twelfth or thirteenth aspect, the driving signal generating means includes a charging means for storing power for generating the driving signal based on a charging command received from the control command means. Is desirable. Charging is performed in advance at an arbitrary timing by the charging means, and electric power for heating the shape memory alloy spring can be obtained from the charging means, so that a large number of movable members are configured in parallel and are simultaneously driven. Since the power demand required for the power supply can be leveled, an increase in the power supply capacity can be suppressed, and the size and weight of the device can be reduced.

In any one of the twelfth to fourteenth aspects, the plurality of shape memory alloy springs are divided into a plurality of groups, and each of the groups is collectively received with the drive command from the control command means. And a drive command distributing means for distributing to the shape memory alloy springs in the group.
By providing the drive command distribution means, drive commands can be quickly supplied to a large number of actuators. In particular, when a drive command is given from a single control command unit,
With a simple configuration, it is possible to control quickly.

In each of the above means, most of the shape memory alloys generate a restoring force only on one side (irreversibly). Therefore, a shape memory alloy spring and an auxiliary spring (bias spring) are used. In addition, it is preferable that the two states are reversibly switched by the balance between the two elastic forces. Of course, some shape memory alloys change shape reversibly, in which case the movable member can be operated alone.

[0026]

Next, an embodiment according to the present invention will be described in detail.

[First Embodiment] FIG. 1 is a longitudinal sectional view showing the structure of a Braille display device according to a first embodiment of the present invention, and FIG.
Is a plan view of the same embodiment. In this embodiment, a plurality of openings 10a are formed in an upper board surface of a case body 10 made of a synthetic resin or the like. The top 11a of the movable member 11 attached to the inside of the opening 10a is configured to protrude and retract. The movable member 11 includes an upper insertion portion 11A having a top 11a at an upper end, and a case 1
The lower insertion portion 11 slidably penetrates a base plate 12 closing a lower opening of the lower insertion hole 11 and having a retainer 11d attached to a lower end thereof.
B, and a flange portion 11C configured to expand in diameter between the upper insertion portion 11A and the lower insertion portion 11B and to protrude to the periphery.

A coil-shaped bias spring 14 is inserted into the upper insertion portion 11A of the movable member 11. The lower end of the bias spring 14 is engaged with the flange 11C, and the upper end of the bias spring 14 is It is engaged with the inner surface of the opening edge of the locking plate 18 fixed inside the opening 10a.

A coil-shaped shape memory alloy spring 15 is inserted into the lower insertion portion 11B of the movable member 11, and the upper end of the shape memory alloy spring 15 is connected to the flange portion 11C via the annular portion 16a of the terminal plate 16. And the lower end of the shape memory alloy 15 is connected to the base plate 12 through the annular portion 17a of the terminal plate 17.
Is engaged with the inner surface of the

In the state shown in FIG. 1, the bias spring 14 and the shape memory alloy spring 15 are balanced by the elasticity of each other, and the top 11a of the movable member 11 is immersed in the opening 10a. .

As the shape memory alloy spring 15, for example, N
What manufactured and processed the i-Ti alloy can be used. This Ni-Ti alloy includes, in addition to a binary alloy of Ni and Ti, Fe, Cu, Nb, C
There are various ternary or higher alloys to which r, V, Co, etc. are added.
The shape memory alloy has a unique reference temperature, and if it is processed in a predetermined shape and subsequently deformed by applying mechanical stress, it will return to its original shape if it exceeds the reference temperature in that state Try to generate the restoring force. Such properties occur due to phase transformation in the shape memory alloy. In the shape memory alloy spring 15, for example, a restoring force to the original shape is developed by utilizing a transformation from a rhomboherald phase (low temperature) to an austenite phase (high temperature). The rigidity change of the shape memory alloy spring at this time is soft in the low temperature phase, and increases in the rigidity when transformed to the high temperature phase. In this case, the temperature from the start temperature to the completion temperature of the austenite transformation is the above-mentioned reference temperature, and conversely, when the temperature is reduced to the low-temperature phase, the temperature from the start temperature to the completion temperature of the Roboherald transformation is the above-mentioned reference temperature Become. When utilizing the phase transformation between the roboherald phase and the austenite phase, the temperature difference between the transformation start temperature and the transformation completion temperature of the austenite phase is about 2-3 ° C. In addition, it is also possible to obtain a driving force using the phase transformation between the martensite phase and the austenite phase.

In these cases, the reference temperature can be set appropriately over a wide range (for example, in the range of −50 ° C. to 100 ° C. in the case of the above-mentioned Ni—Ti alloy) depending on the alloy composition and the like.

The terminal plates 16 and 17 may be made of a conductive material itself, or may have wiring formed on the surface or inside of an insulator. In this embodiment, the terminal plates 16 and 17 are made of a flexible insulating plate. It is configured by forming a conductive pattern on the surface of a substrate. The conductive pattern is made of copper foil or the like, and portions existing on the surfaces of the annular portions 16a and 17a are plated with gold. On the other hand, the upper and lower ends of the shape memory alloy spring 15 are also plated with gold, and the contacts between the upper and lower ends of the shape memory alloy spring 15 and the surfaces of the annular portions 16a and 17a are made by gold plating layers. It has become so.

Terminal plates 16 and 17 are provided from a power supply device (not shown).
When a voltage is applied between the two, a predetermined current flows through the shape memory alloy spring 15 to generate heat by resistance, and the temperature rises. When the temperature of the shape memory alloy spring 15 reaches the above reference temperature, the shape memory alloy spring 15 expands and increases rigidity,
As shown in FIG. 3, since the movable member 11 is pushed upward against the elastic force of the bias spring 14, the top 11a protrudes from the opening 10a. When the power supply device stops supplying power to the shape memory alloy spring 15, the shape memory alloy 15
Is stopped, and the temperature drops below the reference temperature. Therefore, the shape memory alloy spring 15 becomes flexible, and the movable member 11 is pushed down by the elastic force of the bias spring 14, so that the state returns to the state shown in FIG. .

The base plate 12 is fixed to the case body 10 by bolts. A boss 10b shown in FIG. 2 extends downward from the upper inner surface of the case body 10,
The tip of the boss 10b is in contact with the inner surface of the base plate 12.

FIG. 4 is a front view of the movable member 11. The movable member 11 is formed to have substantially the same outer diameter from the upper insertion portion 11A to the top 11a, and the top 11a protrudes and retracts from the opening 10a. Therefore, the outer diameter of the movable member 11 is substantially constant in a portion disposed in the vicinity of the inside and outside of the opening 10a, and no step is formed here. Occurrence can be reduced.

Further, the shape memory alloy spring 15 is
1, and the bias spring 14 that assists the operation of the movable member 11 is also inserted into the movable member 11, so that a partition for supporting and housing these components is not required. As a whole, the size of the Braille display device can be reduced.

Further, as shown in FIG.
The upper insertion portion 11A has a relatively large outer diameter in accordance with the large-diameter bias spring 14, and the lower insertion portion 11B has a relatively small outer diameter in accordance with the small-diameter shape memory alloy 15. In particular, in the present embodiment, since the plurality of movable mechanisms are adjacent to each other without the intermediary of the partition, the outer diameter of the shape memory alloy spring 15 is small.
5 has the advantage that it is possible to increase the distance between them and to reduce the thermal influence between them.
In addition, the outer diameter of the bias spring 14 is
By increasing the outer diameter of the movable member 11, the stability of the movable member 11 can be increased. In this case, the operation of the movable member 11 can be further stabilized by forming the upper insertion portion 11A of the movable member 11 with a large diameter and the lower insertion portion 11B with a small diameter.

In this embodiment, as described above, the terminal plate 1
6, 17 are in contact with each other to receive the elastic force of the shape memory alloy spring 15, and both sides of the contact portion are covered with gold having good contact properties, so that reliable conduction can be obtained. , Operation reliability and durability can be ensured.

Second Embodiment Next, a structure of a second embodiment according to the present invention will be described with reference to FIG. In this embodiment, a case body 20, a movable member 21, a base plate 22, a bias spring 24, a shape memory alloy spring 2
5 and the locking plate 28 are the same as those in the first embodiment, and a description thereof will be omitted.

The present embodiment differs from the first embodiment in that the shape memory alloy spring 25 is heated or cooled by the thermoelectric elements 26 and 27 without passing a current through the shape memory alloy spring 25. different. Thermoelectric element 2
Reference numerals 6 and 27 denote known devices that convert electric power into heat transfer energy. For example, there is a Peltier device having a π-type structure in which a p-type semiconductor and an n-type semiconductor are connected in parallel between electrodes. The thermoelectric elements 26 and 27 include converters 26a and 27a that perform energy conversion, and heat generating units 2 formed on both sides thereof.
6A, 27B and heat absorbing portions 26B, 27A,
a, 27a, a pair of terminal portions 26b,
27b. Heating part 2 of thermoelectric element 26
6A and the heat absorbing portion 27A of the thermoelectric element 27 are configured to abut or come very close to the outer peripheral portion of the shape memory alloy spring 25 arranged inside the case body 21, respectively.

In this embodiment, by heating or cooling the shape memory alloy spring 25 by generating or absorbing heat by the thermoelectric elements 26 and 27, the movable member 21 is formed in the same manner as in each of the above embodiments. Is operated up and down. In this case, the heating and cooling are forcibly performed by the thermoelectric elements 26 and 27, respectively, so that the responsiveness particularly during cooling is improved.

In this case, only one of the thermoelectric elements 26 and 27 is used, or a plurality of thermoelectric elements are operated synchronously.
You may comprise so that the direction of the electric current supplied to one or several thermoelectric elements can be switched. In this case, by switching the direction of the current, the working portion of the thermoelectric element on the side in contact with or in proximity to the shape memory alloy spring becomes a heat generating portion or a heat absorbing portion, and the heating of the shape memory alloy spring 25 is performed. , Cooling can be performed.

<Embodiment of Control System Configuration> Next,
An embodiment relating to a configuration of a control system suitable for any one of the above embodiments or other embodiments having a drive unit structure will be described. The configuration described below relates to a function block of a control system, a control method itself, and the like.

Third Embodiment FIG. 6 shows the configuration of a control system according to a third embodiment of the present invention. This embodiment corresponds to a Braille display device having the drive structure of the first embodiment, and includes a control command means 40 such as a central processing unit (CPU) and a drive signal connected to the control command means. Generating means 41.

The drive signal generating means 41 is controlled by a command from the control command means 40 and forms a basic control signal in pulse width control. The PWM control circuit 42 receives the control signal and generates a control pulse. A constant current circuit 44 configured to flow current only, and an amplification circuit 4 that receives a detection signal from a temperature sensor described later and amplifies the signal.
6 and an AD for converting the amplifier circuit 46 into a digital signal.
(Analog / digital) conversion circuit 47, the temperature command value from control command means 40, and the temperature detection value from AD conversion circuit 47 are appropriately compared, and the temperature command value and the temperature A comparison means 48 including a digital comparator for sending an appropriate command signal determined by the detected value is provided.

The drive signal output from the constant current circuit 44 flows through the shape memory alloy spring 15 via the terminal plates 16 and 17, and raises the temperature of the shape memory alloy spring 15 by resistance heating. The temperature sensor 19 includes a shape memory alloy spring 15
Alternatively, the temperature of the surrounding area is detected and a detection signal is sent to the amplifier circuit 46.

In the present embodiment, based on the temperature detection value obtained from the temperature sensor 19 and the temperature command value included in the temperature control data signal given from the control command means 40,
Further, a current is supplied to the shape memory alloy spring 15 in accordance with a predetermined drive data signal given from the control command means 40. The drive signal generated by the drive signal generating means 41 drives the shape memory alloy spring 15 by pulse width control. FIG. 8 shows the relationship between the drive signal Pop in the pulse width control and the amount of heat generated by the shape memory alloy spring 15 receiving the drive signal Pop. Generally, the pulse width of the drive signal increases as the difference (temperature difference) between the temperature command value and the detected temperature value increases, and the heat transfer also increases.

The comparison means 48 is in the normal input mode, receives the temperature control data signal TD from the control command means 40, takes in the temperature command value included in the temperature control data signal TD at a predetermined timing, and stores it inside. Comparison means 4
The temperature command value stored in 8 is not changed unless a different temperature command is issued from the control command means 40 and is taken into the comparing means 48. Therefore, the comparing means 48
Unless a new temperature command value is taken in the data, the difference data obtained based on the same temperature command value (difference between the temperature command value and the detected temperature value, or another value corresponding thereto) is PWM. It is configured to send it to the control circuits 42 and 43.

The comparing means 48 is provided with the control command means 40.
If the temperature control data signal TD includes an instruction to return the detected temperature value, the mode is temporarily changed to the output mode,
The temperature detection value is sent to the control command means 40. At this time, the control command unit 40 grasps the temperature environment of the drive unit based on the detected temperature value returned from the comparison unit 48, and outputs the next command according to the temperature environment.

The control command means 40 issues a drive data signal to the PWM control circuit 42 and controls the output of a drive pulse whose pulse width is controlled by the PWM control circuit. For example, even if the detected temperature value is lower than the temperature command value, the drive signal is not output unless the drive data signal is turned on. In this case, more advanced control can be performed by the control command means 40. For example, based on the detected temperature value returned by the comparing means 48,
If the temperature detection value is considerably lower than the temperature command value, the maximum duty ratio of the normal drive pulse is set regardless of the value of the temperature difference, or if the temperature command value-the temperature detection value is positive,
That is, the control coefficient of the pulse width control is changed depending on the case where heating is required and the case where the temperature command value−the detected temperature value is negative, that is, the case where cooling is required.
Such as using the optimal control coefficient according to the cooling history,
Control contents that are difficult with the PWM control using a normal hardware configuration can be easily performed by changing the control mode.

[Fourth Embodiment] Next, an example of another control system for controlling the drive unit of the second embodiment will be described with reference to FIG. This control system is configured particularly for the purpose of improving the responsiveness of the Braille display device and optimizing the case where many Braille display devices are connected to a common control command unit.

In the drive signal generating means 70, the power supplied from the constant voltage circuit 71 is
The charging circuit 72 is charged by turning on (for example, charging when on (high potential) and stopping when off (low potential)), and power is supplied from the charging circuit 72 to the constant current circuit 73. ing. With such a configuration, a sudden power demand generated when controlling and driving a plurality of movable members in the Braille display device is reduced by the constant voltage circuit 71.
It can be driven by discharging from the charging circuit 72 without being generated in the power supply unit. On the other hand, since the charging of the charging circuit 72 can be set to be performed relatively slowly by the circuit configuration in the charging path, the power supply control signal DCC given from a control command unit (not shown) or the like allows the charging to be performed.
Electricity demand can be distributed. In particular, even if many movable members start operating at the same time, the peak value of the power demand can be suppressed.

In this embodiment, the drive data signal DD and the drive latch signal DR are input to the D flip-flop 74a, and the output Q of the D flip-flop 74a is input to one input terminal of the AND circuit 74b. AND circuit 74
The output of the PWM control circuit 74 is input to the other input terminal b. On the other hand, as in the previous embodiment, the amplifier circuit 76,
An AD conversion circuit 77 and a comparing means 78 are provided. The comparing means 78 receives a temperature latch signal TR and a temperature control data signal TD indicating a temperature command value. The output of the comparing means 78 is difference data between the temperature command value and the detected temperature value,
The signal is input to the PWM control circuit 74. PWM control circuit 74
Is a pulse signal having a pulse width corresponding to the difference data, similarly to the drive signal shown in FIG.
The signal is input to another input terminal of the input terminal 4b and also input to the AND circuit 74c. The inverted output of the D flip-flop 74a is also input to another input terminal of the AND circuit 74c. Further, a transistor 73b is provided to receive the output of the AND circuit 74c and prompt the output of the constant current circuit 73.

A predetermined pulse signal is output from the AND circuit 74b only when the drive data signal DD is in the ON state (eg, high potential "H") at a timing synchronized with the drive latch signal DR, and is input to the base of the transistor 73a. Then, a pulse signal is supplied from the constant current circuit 73 to the thermoelectric element 26, and the shape memory alloy spring 25 is heated. When the drive data signal DD is off (for example, low potential “L”), AN
A predetermined pulse signal is output from the D circuit 74c and applied to the thermoelectric element 27 to cool the shape memory alloy spring 25. The temperature sensor 29 detects the temperature of the shape memory alloy spring 25 and outputs a detection signal to the amplifier circuit 76.

In this embodiment, the shape memory alloy spring 25 is preheated to a preset preheating temperature T1 before driving a certain movable member of the Braille display device and while the driving is stopped, Some measures have been taken to shorten the response time after the start of driving or the restart of driving. As shown in FIG. 9, when the temperature command value T1 is transmitted by the temperature control data signal TD from the control command means, it is taken into the comparing means 78 by the temperature latch signal TR, and the drive data signal DD
Is turned on, a drive signal is output from the constant current circuit 73 to the thermoelectric element 26 by the drive latch signal DR, and the shape memory alloy spring 25 is heated. The temperature of the shape memory alloy spring 25 increases, and gradually approaches the temperature command value T1 by feedback control.

Here, the temperature control data signal TD sent from the control command means to the comparing means 78 is a 4-bit control data sequence S3, S2, S4 as shown at the bottom of FIG.
1, S0 and 8-bit temperature data strings T7, T6, T
12, T4, T3, T2, T1, and T0. Here, the command content from the control command means is transmitted to the comparing means 78 by the numerical value indicated by the control data string of the temperature control data signal TD,
The temperature command value from the control command means, the PWM coefficient value, and the like are transmitted to the comparing means 78 by the numerical value indicated by the temperature data string. Table 1 below shows examples of numerical values of the control data string in the temperature control data signal TD and their meanings.

[0058]

[Table 1] Numerical value of control data string Command details 1 Set to heating temperature data input mode. 2 Set to the cooling temperature data input mode. 3 Set to the detected temperature output mode. 4 Set the temperature command value-temperature detection value (difference data) output mode. 5 Set to the heating PWM coefficient input mode. 6 Set to the cooling PWM coefficient input mode.

When the control data string indicates 1 or 5, the numerical value indicated in the temperature data string is stored in the comparing means 78 as a heating-side temperature command value or a heating-side PWM coefficient. When indicating 2 or 6, the numerical value indicated in the temperature data string is the cooling-side temperature command value or the cooling-side P
It is stored in the comparison means 78 as a WM coefficient. The mode for entering the cooling temperature data input mode is effective only in the case where the cooling mechanism is present. Therefore, the mode is effective in the present embodiment, but is invalid in the absence of the cooling mechanism. If the control data string indicates 3, the comparison means 78 is changed to the output mode, and sends back the temperature detection value sent from the temperature sensor to the control command means. Further, when the control data string indicates 4, the comparing means 78 outputs the difference data to the control command means.

When the control command means knows from the data returned from the comparison means 78 that the detected temperature value has almost reached T1, the drive is ready for driving, and is ready for driving according to the command from the control command means. Become.

In the preheating state as described above, the temperature control data signal TD from the control command means notifies the temperature command value T2, and the temperature command value T2 is taken into the comparison means 78 by the temperature latch signal TR in the same manner as described above. Then, the temperature starts to rise due to the difference data output by the comparing means 78. If the temperature command value T2 is higher than the reference temperature, the shape memory alloy spring 25 will operate soon, and the movable member 22 will rise. In the drawing, PH indicates a preheating preparation period, PP indicates a preheating period, DP indicates a driving period, and NDP indicates a non-driving period.

As described above, by preheating the shape memory alloy spring 25 before driving the Braille display device, the time until the start of operation can be shortened, and the Braille display device can be operated within a short time. it can. As shown by the dotted line in FIG. 9, the operation start time can be greatly reduced as compared with the case without preheating.

FIG. 10 shows the charging circuit 7 in this embodiment.
2 shows the relationship between the amount of charge and the driving state. In this case, a case in which a certain movable member 21 in the Braille display device is driven intermittently (so as to appear and disappear) will be described as an example.

After the driving of a certain movable member 21 (supply of current to the thermoelectric element 26) in the Braille display device is interrupted and the power control signal DCC from the control command means is turned on, the charging circuit 72 (for example, a large capacity capacitor) , Etc.) from the constant voltage circuit 71. After a while after the voltage of the charging circuit 72 gradually rises from the initial V0 and reaches the saturation voltage Vsat, the power supply control signal DCC is turned off and the charging ends. At this time, even if the charging is not completed, if the drive is possible, the preheating is started as described above, the temperature command value is changed from T0 to T1, and the preheating preparation is started as described above, and then the preheating is started. Is completed (preheating period PP). Thereafter, the driving of the Braille display device is started as described above. After driving starts, the power control signal turns off,
Temperature control is performed until the driving state is released. When the driving state is released, the driving data signal D
D is turned off, and the driving is stopped by the driving latch signal. Thereafter, driving and stopping are repeated, and the charging circuit 72 is stopped.
To the power supply control signal DCC again as described above.
Is repeated by In this case, charging may always be performed at the timing of FIG. 10 according to the intermittent drive cycle,
Alternatively, the charging may be performed at appropriate intervals according to the driving amount or the charging amount, regardless of the driving timing.

As described above, the charging circuit 72 provided for each movable member in the Braille display device is appropriately charged,
By supplying power from the charging circuit 72, even when power is supplied from a common power supply circuit to thermoelectric elements for driving a plurality of movable members in the Braille display device,
Even if a plurality of Braille display devices receive power supply at once, the power supply capacity does not become insufficient, the capacity of the power supply circuit can be reduced, and the drive control system can be reduced in size and weight as a whole. .

In the third embodiment and the present embodiment, the temperature may be detected by detecting the resistance value of the shape memory alloy spring itself instead of the temperature sensor. Since the resistance of the shape memory alloy spring itself changes depending on the temperature, it can be used for temperature detection similarly to the thermistor. In order to adjust the relationship between the temperature and the resistance value of the shape memory alloy, appropriate data compensation may be performed in an amplifier circuit, a comparison unit, or the like.

[Fifth Embodiment] Finally, an embodiment of a system for driving a plurality of Braille display devices will be described with reference to FIG. In this embodiment, as shown in FIG. 11, the Braille display device is provided with a plurality of movable mechanisms ACT, and correspondingly, a plurality of drive signal generation means DC is also provided. Here, as the movable mechanism ACT,
Any operating part of the first or second embodiment and the modified examples thereof (a part including at least the movable members 11 and 21 and those corresponding to the shape memory alloys 15 and 25 acting on the movable members 11 and 21 and In the form, the bias spring 1
4,24 are also included. ), And the drive signal generating means may be any of the drive signal generating means 41 and 70 of the third or fourth embodiment and its modified examples. However,
In FIG. 11 and the following description, it is assumed that the driving signal generation unit 70 according to the fourth embodiment is used.

Each of the drive signal generation means DC receives a temperature control data signal TD from a control command means (not shown) and receives a line derived from a selector SL for distributing the signal. The selector includes a demultiplexer that distributes a data signal by a predetermined control signal. Further, the drive signal generation means DC is provided with the temperature latch signal T described in the third or fourth embodiment.
R, drive latch signals DR1, DR2, power control signal DC
Each line for transferring C is connected. The latter line is a common line for a plurality of drive signal generation means DC.

Drive data signals DD1 and DD2 are introduced into shift registers SR1 and SR2, and drive latch signals
It is supplied to each drive signal generation means DC based on R1 and DR2. Here, half of the drive signal generating means DC corresponding to the plurality of movable mechanisms ACT are controlled by the shift register SR1 and the drive latch signal DR1, and the other half are shifted by the shift register SR2 and the drive latch signal D1.
Controlled by R2.

In this example, a temperature command value such as temperature data and a drive data signal are received for each drive signal generating means DC, the temperature command value is read by a common temperature latch signal, and individual Braille signals are read by a common drive latch signal. The display device is configured to be driven on and off.

In this embodiment, the plurality of movable parts of the Braille display device are divided into two groups, and the driving data signal DD
1, DD2 and the drive latch signals DR1, DR2 are transmitted for each group, so that the drive can be quickly switched to a large number of movable parts.

In the above-described embodiment, the load on the power supply capacity can be reduced by providing a charging circuit in each drive signal generating means DC, but the power supply control signal DCC is further shifted in timing for each group. By switching, power supply and demand in the case of multiple driving can be further smoothed, and the capacity of the power supply circuit can be reduced.

[0073]

As described above, according to the present invention, the movable member is provided with the engaging portion that penetrates the shape memory alloy spring and engages the shape memory alloy spring in the axial direction. The shape memory alloy spring acts on the movable member via the engaging portion to drive the movable member, and the shaft can support the shape memory alloy spring. In addition, since it is not necessary to provide a support portion that supports the shape memory alloy spring from the periphery such as a partition wall that supports and accommodates the shape memory alloy spring, the size of the device can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a schematic structure of a first embodiment (mechanical structure) of a braille display device according to the present invention.

FIG. 2 is a plan view of the first embodiment.

FIG. 3 is a longitudinal sectional view showing a state where a movable member protrudes in the first embodiment.

FIG. 4 is a front view showing a shape of a movable member according to the first embodiment.

FIG. 5 is a longitudinal sectional view showing a schematic structure of a second embodiment (mechanical structure) of the braille display device according to the present invention.

FIG. 6 is a configuration block diagram illustrating a third embodiment (configuration of a control system) of a braille display device according to the present invention.

FIG. 7 is a configuration block diagram illustrating a fourth embodiment (configuration of a control system) of a Braille display device according to the present invention.

FIG. 8 is a graph showing a drive signal by pulse width control in the third and fourth embodiments.

FIG. 9 is a timing chart showing an operation when performing preheating drive in a fourth embodiment.

FIG. 10 is a timing chart showing an operation when performing a charging drive in a fourth embodiment.

FIG. 11 is a configuration block diagram illustrating a fifth embodiment (configuration of a control system) of a braille display device according to the present invention.

[Explanation of symbols]

 10, 20 Case body 10a, 20a Opening 11, 21 Movable member 11A, 21A Upper insertion part 11B, 21B Lower insertion part 11C, 21C Flange part 11a, 21a Top part 14, 24 Bias spring 15, 25 Shape memory alloy spring 16 , 17 terminal board 26, 27 thermoelectric element 40 control command means 41, 70 drive signal generation means ACT movable mechanism DC drive signal generation means SR1, SR2 shift register

Claims (15)

[Claims] 1. A plurality of movable members configured to be able to protrude and retract from an opening formed in a board surface, and a predetermined shape restoring force when a predetermined temperature or a temperature range exceeds or falls below the reference temperature. A plurality of coil-shaped shape memory alloy springs for generating and moving each of said movable members, and a temperature control means for heating and / or cooling said shape memory alloy spring; The Braille display device, characterized in that the movable member includes an engaging portion that penetrates the shape memory alloy spring and engages the shape memory alloy spring in the axial direction. 2. The Braille display device according to claim 1, wherein the movable member has an outer diameter that is substantially equal to a direction in which the movable member comes and goes in a portion disposed inside and outside the opening. 3. The coil-shaped auxiliary spring according to claim 1, wherein the movable member is engaged with the shape memory alloy spring from the opposite side of the shape memory alloy spring to the engagement portion. A braille display device, which is inserted in the direction of an axis. 4. The Braille display device according to claim 3, wherein one of the shape memory alloy spring and the auxiliary spring is engaged inside an opening edge of the opening. 5. The Braille display device according to claim 3, wherein a coil radius of the shape memory alloy spring is smaller than a coil radius of the auxiliary spring. 6. The movable member according to claim 5, wherein
A first insertion portion through which the shape memory alloy spring is inserted, and a second insertion portion through which the auxiliary spring is inserted, wherein the outer diameter of the first insertion portion is larger than the outer diameter of the second insertion portion. A Braille display device characterized in that it is also smaller. 7. A plurality of movable members configured to be able to protrude and retract from an opening formed in a board surface, and a predetermined shape restoring force when the temperature exceeds or falls below a predetermined temperature or temperature range as a reference temperature. A plurality of coil-shaped shape memory alloy springs for generating and moving each of the movable members, and a power supply means for applying a current to the shape memory alloy spring to heat the shape memory alloy spring; A braille display device, comprising: a terminal member that comes into contact with an elastic force and is conductively connected to the shape memory alloy spring, and power is supplied from the terminal member to the shape memory alloy spring. 8. The material according to claim 7, wherein a contact portion of the shape memory alloy spring with the terminal member and a surface portion of the terminal member contacting the contact portion are made of a material having good electric contact properties. A braille display device comprising: 9. A movable member configured to be able to protrude and retract from an opening formed in a board surface, and generates a predetermined shape restoring force when a predetermined temperature or a temperature range exceeds or falls below the reference temperature. A braille display element comprising: a shape memory alloy spring for moving the movable member in and out; and a temperature control means for heating and / or cooling the shape memory alloy spring, wherein the temperature control means has a thermoelectric element. A Braille display device characterized in that the shape memory alloy spring is heated and / or cooled by a heat generating part and / or a heat absorbing part in a thermoelectric element. 10. The temperature control device according to claim 9, wherein the temperature control means is configured so that the thermoelectric element heats and cools the shape memory alloy according to the temperature of the shape memory alloy spring. Braille display. 11. The shape memory alloy spring according to claim 1, further comprising a temperature detecting means for detecting a temperature of the shape memory alloy spring, wherein the temperature detecting means detects a temperature of the shape memory alloy spring based on the temperature detected by the temperature detecting means. A braille display device for adjusting an electric or thermal control amount. 12. The shape memory according to any one of claims 1 to 11, based on control command means for controlling the plurality of movable members, and a drive command received from the control command means. A braille display device comprising: a drive signal generating means for generating a drive signal for heating or cooling an alloy spring. 13. The driving signal generating unit according to claim 12, wherein the control command unit sets the standby temperature set to a value between the normal temperature and the reference temperature before the driving is stopped or before the driving is started. Thus, the Braille display device is configured to heat or cool the shape memory alloy spring in advance. 14. The method according to claim 12, wherein
The drive signal generating means includes a charging means for storing electric power for generating the drive signal based on a charge command received from the control command means. 15. The drive command from the control command unit according to claim 12, wherein the plurality of shape memory alloy springs are divided into a plurality of groups, and the plurality of groups are collectively grouped. And a drive command distribution means for receiving and distributing the drive command distribution to the shape memory alloy springs in the group.