The invention applies to the field of devices for transmitting tactile information to a user. It relates more particularly to a device comprising a tactile interface formed by a plate having a surface to be modified in a controlled manner, the plate comprising an array of elements for modification of the surface.
Such plates are especially employed in touch plates or tactile interfaces for communicating information for example in the field of cars or in communicating objects, for example portable telephones or computer mice or in the field of objects for blind people.
The invention applies also to the field of virtual reality, for example for reproducing the sensation of a texture.
U.S. Pat. No. 6,159,013 describes a portable optic sensor for blind people. The device comprises a touch plate fitted with holes in which surface element modification of the plate constituted in this case by rods are mobile. The position of the rods is controlled electromagnetically.
An address circuit associated with address control means receiving the tactile data to be displayed determines the circulation of currents in control coils of the position of the rods.
According to its position, a rod emerges or does not emerge from a touch surface of the touch plate. The control of each of the rods allows forming of patterns on the plate.
There are also tactile interfaces based on thermal actuators, especially shape memory alloys (SMA) utilising only wires as actuators. The movement of the part actuated by the wire is slight. Various solutions have been put forward for amplifying the movement of the mobile part, especially by using lever arms and return springs. However, as soon as it is preferred to increase the resolution of the touch plate, that is, increase the number of modification elements per surface unit of the plate, the assembly of plate and elements becomes very complicated and the system becomes bulky.
The shape memory alloys (SMA) are known per se. These are alloys capable of transforming thermal energy provided to them during mechanical work. They can thus give back deformations of the order of 6 to 8% and generate relatively significant efforts when they are heated. In addition, the SMA are in general low in cost and the physical implementation of the heating operation can be carried out simply. When a piece made of SMA passes from a first to a second temperature, its mechanical form changes and passes from a first to a second form. Two-way effects can also be obtained. For this purpose the material is given a first shape. It is heated in this first shape, then cooled; it retains its first shape. It is then subjected to thermal cycle processing in a second shape. After this thermal cycle processing the material has, in the hot state, the first shape and, in the cold state, the second shape.
The aim of the present invention is a device comprising a tactile interface formed by a plate. The plate has a surface capable of being modified in a controlled manner. For this purpose the plate comprises an ensemble of mobile parts of the modification element of the surface which is simple to produce and compact. The aim of the present invention is likewise a device comprising a tactile interface having large modification resolution. When it comes to plate, this does not necessarily signify only the plate with a flat shape. It can be for example a cylindrical surface in the geometric sense. It can also be one or more layers deposited on a substrate by technologies used in microelectronics.
According to the present invention these aims are reached by the fact that in the device comprising the tactile interface the plate is made of a shape memory material, or comprises at least one sub-plate made of such a material. Also, the array of mobile parts of modification elements of the plate is made up of an array of one or more blade(s) solid monolithically with the plate by one or more arms solid monolithically with the blade and the plate, one or more recesses to release blade(s) being present on a part of a perimeter of the blade, the blade having a first position at a first temperature and a second position at a second temperature. The device comprises control means of the surface element modification.
To pass from the first to the second form, it suffices to apply local heating to the blade or preferably to a linking arm of the blade on the rear of the plate. To return from the second to the first position of the blade, it suffices to let it cool. It can also be cooled actively, for example by means of a Pelletier cell.
According to a first advantageous embodiment in which the plate is made of a shape memory material, the return to the first form is achieved by the fact that the plate has undergone thermal processing allowing two-way effect. In this case a first heating of a part from the plate causes a change in shape of this part from a first form to a second form. Cooling of this same part causes a return to the first form. This first embodiment allows control of the rest time of a pattern made on the plate.
According to a second embodiment in which the plate is made of a shape memory material, the blade is attached to the plate by several arms. One (or several) first arm(s) has (have) a memorised form, which it recovers by heating, and one (or more) second arms have not undergone local thermal processing. The return of the blade to the first form is assured or accelerated by the fact that the second arms exert an elastic return force on the first arms for returning the blade to its initial position.
According to a variant of this second embodiment where the return to the first form is effected by elastic means, the plate is formed with two sub-plates assembled for example by welding or bonding so as to form only a single plate. A first sub-plate is made of a shape memory material A. A second sub-plate is made of an elastic material B. A heated part of the first sub-plate made of material A will cause deformation of this part by deformation of the material causing elastic deformation of the material B. When, due to the fact of natural or active cooling of the material A, the material A is less rigid, the return of the material B to its initial form by elastic effect causes return to the first form of the materials A and B.
According to a third embodiment, in which the plate is made of shape memory material A, the plate is made up of two sub-plates made of shape memory material, a material A and a material C, identical or different to one another, for example in the form of two sub-plates welded or bonded to one another to form one single plate. Parts of the sub-plate made of material A have a first form in the cold state and a second form in the hot state. Corresponding parts of the sub-plate made of material C have a first form in the cold state and a second form when hot. The second form in the hot state of the corresponding part made of material C is such that in this form the sub-plate resumes its first form. This works as follows:
A part of the sub-plate made of material A for example, is deformed by heating and resumes its memorised form. The deformation of the part made of material A causes mechanical deformation of the corresponding part of the sub-plate made of material C. If at this stage the alloy C is heated, the alloy C resumes its memorised form such that the ensemble of the two alloys resumes the initial form.
In this third embodiment the two layers of material A and C are preferably attached to one another by means of a thermal insulating layer. The layers of material A and C can thus be heated independently. This third embodiment allows, as does the second form, control of the rest time of a pattern made on the plate.
In an embodiment the control means of the transformation means of the modification elements of the tactile sensation comprise one or more laser emitters whereof the radiation from each is utilised to effect transformation of one or more transformation means of modification elements of the tactile sensation.
The control means further comprise, as in the prior art, a control circuit for selecting, as a function of tactile data to be displayed at any given instant, the modification elements of the tactile sensation on which it is necessary to act to obtain display of the tactile data, and direct the radiation from the laser emitter to these selected elements. In the prior art these control means comprise an address circuit, and a control circuit of the address circuit which directly controls the address circuit addressing the elements which must be acted on.
This same configuration of the control means can be found in the invention for cases where there are as many laser emitters as transformation elements, each transformation element being in bijective correspondence with a laser emitter.
In general, there are one or more laser emitters, at least one of the laser emitters acting on several transformation elements. When there is a single laser emitter for all the transformation elements, the control means acting on shift means of the radiation output by this laser emitter to successively apply the radiation to the transformation elements which must be acted on, considering the tactile data to be displayed. When there are several laser emitters whereof some act on several transformation elements, the control circuit is in two stages, a first selection stage of the lasers whereof the radiation will be used to create the display, for example in the form of an address circuit controlling the emission of radiation of the laser emitters, these laser emitters being in correspondence, by way of distribution means of the radiation, with transformation means necessary for the formation of the projected display of the tactile data, and a second stage acting on shift means for shifting the radiation emitted by each laser whereof the radiation is utilised for the projected display, for successively applying the radiation to the transformation elements in correspondence with this laser emitter, which is to be acted on considering the tactile data to be displayed.
This aspect of the control means, relative to selection of the radiation useful for a given display and of the control of shifts of the radiation, is within the knowledge of the specialist and will not be taken up further in the present description.
There can be as many lasers as modification elements of the tactile sensation provided. Each of the radiations in this case heats or does not heat a modification element of the tactile sensation. In this way the radiation from a laser is placed in bijective correspondence with a modification element of the tactile sensation.
In the preferred embodiment of the invention, the control means of the elements of the tactile sensation comprise a laser emitter controlling a plurality of modification elements of the tactile sensation and means for mobilising the radiation with one or two degrees of freedom.
In this case, the tactile sensation will be renewed at a frequency which is a function of the power of the laser, the number of the means of transformation with which a laser is associated, the application time necessary for passing from the rest position to the work position, and the rate of shift made possible by the means for moving the radiation with one or two degrees of freedom.
In the case where the radiation is rendered mobile with a degree of freedom and where the modification elements of the tactile sensation are constituted by a matrix unit in lines and columns, the radiation from a laser common for example to the transformation means of the modification elements of the tactile sensation of a line can be directed successively for example towards each of the modification elements of the tactile sensation of the line to be modified. This control could be effected by first translation means of the laser assigned to this line, or by a reflector controlled in rotation, receiving the radiation from the laser, the rotation of said reflector controlling the rotation of the radiation received to send it to the transformation means of the line which require transformation.
In the case where the radiation is rendered mobile with two degrees of freedom, these two degrees in a first embodiment are constituted by translation means of the laser and a reflector controlled in rotation at the same time. Preferably, in this case the axis of rotation of the reflector is parallel to the translation vector. In this case the translation or rotation means control translation of the translation or the rotation means of the reflector respectively, to send the radiation to a part at least of the modification elements of the display device.
In a second variant of the embodiment comprising one or more lasers with displacement of the radiation according to two degrees of freedom, the second degree of freedom is obtained by the fact that second translation means are added to first translation means, or by the fact that the reflector is rendered mobile in rotation according to two non parallel axes.
In the case of translation it could suffice to shift, for example by means of a double-axis translation plate, one end of a fibre optic whereof the other end receives the radiation from the laser. The same applies in the case of rotation of the reflector, where the incident radiation reaching the reflector could originate from a fibre optic receiving the radiation from the laser.
In the preferred embodiment the shape memory relates only to the linking arm or arms of the blade in continuum of the plate, the arms having a first form above a predetermined temperature and a second form below this temperature. The modification elements of the tactile sensation are thus each constituted by the one blade and its link arm or arms. The blade is a mobile organ linked mechanically to the arm. The radiation output by the laser acts by heating the arm or arms.
Therefore the device according to the present invention enables thermal operation without electrical contact, and this reduces the complexity of the addressing and makes production easier.
Other advantages and characteristics of the invention will emerge from the following description of exemplary embodiments.
Embodiments of the invention will now be described in reference to the attached drawings in which the same reference numerals are used for identical elements or having the same function.
Part A illustrates a transversal sectional view of a plate according to a third embodiment of the invention.
Part B illustrates a plan view of a first sub-plate of a third embodiment of one of the modification elements of the plate.
Part C illustrates a view from below of a second sub-plate of the third embodiment of one of the modification elements of the plate,
Part D illustrates a plan view of the third embodiment of one of the modification elements of the plate, the first and second sub-plates being assembled.
Parts E and F illustrate respectively sections according to the lines EE and FF of parts B and C of the shape form of the first and second sub-plates respectively.
Embodiments of modification elements 25 of the plate 10 will now be described in conjunction with FIGS. 2 to 4.
The shape memory material will be for example nickel-titanium or a copper alloy shape memory material, for example, CuZnAl or CuAlNi or CuAIBe.
The form of the element 25 shown in
In the embodiment shown in
According to a variant of this first embodiment an element 25 of the plate 10 has in a plan view the form above mentioned in relation to
Therefore, in this embodiment and in its variant, modification elements 25 of the surface 10a of the plate 10 comprising the shape memory material, incorporating elastic elements 15, 13b mechanically connected on the one hand to the plate 10 and on the other hand to the modification element 25 to which they belong, these elastic elements exerting a return force on the modification element 25 of the surface of the plate 10 to take it from the second to the first form.
According to a third embodiment shown in
The heating can be applied by any known means. It can also be applied by irradiation by a laser beam scanning the zone to be heated.
The assembly of the parts 25a and 25c is shown in a plan view in
This operates as follows:
The part a of the sub-plate 16 made of material A for example is deformed by heating and regains its memorised form. This form is shown in a transversal section in
The display device 1 comprises a touch plate 10, as described hereinabove in relation to
The device 1 also comprises control means 40 for selectively addressing the transformation means 21 of the modification elements 25 of the tactile sensation, so a to produce at any instant a tactile sensation determined at the level of the whole of the surface 10a of the touch plate 10.
In keeping with this embodiment of the invention, the control means 40 of the modification elements 25 of the tactile sensation comprise one or more laser emitters 42 whereof the radiation from each is utilised to make the transformation from one or more modification elements 25 of the tactile sensation. In
It is not obligatory that the laser emitter 42 is shifted. It could be enough, as shown in
Thus in the example shown in
For each tactile image to be formed, the radiation laser is shifted successively by means of the table 43, towards the modification elements 25 of the tactile sensation, which must be transformed into a working position, to form the image. Transformation can be achieved in a single pass, with a stop time on each modification element of the tactile sensation sufficing to cause transformation of the element. Transformation can also be achieved in a number of successive passes, with the total of the successive stop times on each modification element 25 of the tactile sensation being sufficient to cause transformation of the element. A next image following a former image is applied in the same way after the time necessary for the return of the modification elements 25 of the tactile sensation to a rest position.
The operation is the same as in the example shown in
In this third embodiment the control means 40 comprise a monolithic layer 30, preferably obtained by utilisation of collective fabrication techniques, especially micro-electronics. This layer comprises a number of lasers 42 equal to the number of modification elements 25 of the tactile sensation. The radiation from a laser emitter 42 can be applied univalently to a single element 25. The control circuit 41 is in this case a simple address circuit for emitters 42 which must emit for the formation of a current image. Although this embodiment requires an address circuit which can become complex if the number of elements 25 to be addressed is large, it has the advantage of being able to be made according to collective manufacturing techniques, as mentioned earlier for the layer 30, but also for the touch plate 10, and the address circuit 4.
Number | Date | Country | Kind |
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02/16177 | Dec 2002 | FR | national |
03/50092 | Apr 2003 | FR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/FR03/50187 | 12/17/2003 | WO | 2/10/2006 |