WO2004070450A1

WO2004070450A1 - Object orientation device

Info

Publication number: WO2004070450A1
Application number: PCT/FR2004/050034
Authority: WO
Inventors: Claire Divoux; Eric Ollier; Stéphane CAPLET
Original assignee: Commissariat A L'energie Atomique
Priority date: 2003-01-31
Filing date: 2004-01-28
Publication date: 2004-08-19
Also published as: FR2850762A1

Abstract

The invention relates to a device (200) which is used to orient an object such as a mirror. The inventive device comprises a substrate (2), an object (4) and at least one object support contact block (6, 6', 6'). The device also comprises electrostatic actuation means which can move the object to a plurality of positions and which comprise a first assembly (208) which is solidly connected to the substrate. According to the invention, a second assembly (110) is disposed between the substrate and the object. The device further comprises a contact block (6') which is disposed between the second assembly and the substrate as well as a block (6') which is disposed between the second assembly and the object. The aforementioned second assembly can be pressed against the substrate when the electrostatic actuation means are activated.

Description

OBJECT ORIENTATION DEVICE DESCRIPTION

TECHNICAL AREA

The present invention relates to a device for orienting an object, comprising an object to be oriented or "deflected" such as a mirror, an optical lens or a series of optical lenses, this object being capable of occupying a plurality of positions relative to a substrate. More particularly, the invention relates to a device for orienting a mirror, for example having a size of less than a few hundred microns, and which can be moved into any one of the plurality of positions relative to the substrate, by means of electrostatic actuation means.

The invention finds a very particular application in the field of screens equipping conventional display means or scanners, as a reflection device allowing the realization of a scan. In addition, the invention also finds an application in the field of optical telecommunications for the production of optical switches.

STATE OF THE PRIOR ART From the state of the art, the existence of a conventional light reflection device is known, comprising a mirror capable of being adjusted using electrostatic actuation means. These means usually include two electrically conductive assemblies, which depending on the value of the supply voltage applied to them, cause a determined inclination of the mirror relative to the substrate of the device.

In fact, in such a reflection device, a first assembly is typically constituted by electrodes distributed on the substrate so as to be opposite a second assembly, usually taking the form of an internal conductive surface of the mirror. This mirror is kept at a distance from the substrate by means of holding means cooperating with an end portion of the mirror, and extend outwardly therefrom. By way of example, the holding means may take the form of a frame supporting the end portion of the mirror, this frame being provided with a plurality of flexible arms connecting the holding means to a fixed part of the device, such as its substrate.

Thus, when a supply voltage is applied between the internal conductive surface of the mirror and one or more electrodes of the substrate, the electrostatic force or forces generated between these elements cause the mirror to tilt in a determined position, authorized by the flexibility of the means of support. Note that this position is also a function of the value of the supply voltage applied between the conductive assemblies of the actuating means. Thus, following the activation of the electrostatic actuation means, a ray or a light beam can be reflected at a particular angle of inclination of the mirror relative to the substrate of the device. However, the use of such electrostatic actuation means has certain major drawbacks, which may limit the performance of the device, and / or make its design more complex.

As such, it is specified that when the distance between the internal surface of the mirror and the electrodes of the device is small, the voltage necessary to apply to cause the mirror to tilt is relatively small. However, in such a case, despite the possibility of using a simple electrical supply, the geometry obtained then inevitably limits the maximum value that the angle formed between the mirror and the substrate of the device can take.

Furthermore, to remedy this problem, it remains possible to increase the distance between the internal surface of the mirror and the electrodes, in order to be able to have a greater inclination, and therefore to present a reflection device. with increased performance. On the other hand, this solution is also restrictive in the sense that the supply voltage required to cause the tilting of the mirror is very high, which thus greatly complicates the design of the device, and more particularly that of its electrical supply.

As has just been explained above, when the actuation means of the reflection device are electrostatic means such as those which have just been presented, it remains impossible to simultaneously offer a low supply voltage and a high maximum tilt angle, so that when designing this type of device, it is constantly necessary to find a compromise between these two values.

On the other hand, it should be noted that when a voltage is increasingly applied between one of the electrodes of the substrate and the internal surface of the mirror, the electrostatic force created causes a relative movement between these elements. The relative movement between these two elements is controlled until the application of a supply voltage limit value, beyond which the short distance between the activated electrode and the internal surface of the mirror generates an electrostatic force if important that this inevitably leads to an abrupt plating of this mirror against the substrate.

Thus, the phenomenon of abrupt plating (from the English “pull-in”) makes it possible to ensure controlled movement of the mirror only over a limited operating range, insofar as this mirror cannot adopt any stable position between the position obtained during the application of the supply voltage limit value, and the position in which it is pressed against the substrate.

Furthermore, if the sudden plating phenomenon considerably restricts the maximum angle that the mirror can form with the substrate before these two elements are pressed against each other, this maximum value is also reduced by the need to take a safety margin so that in resonance, the mirror of the device does not exceed the limit angle of instability.

To increase the maximum value of the angle formed between the substrate and the mirror, another type of device has been proposed, in which these two elements are spaced and connected to each other by means of a mirror support stud.

In this type of device, the electrostatic actuation means are generally similar to those described above, with electrodes arranged on the substrate so as to be distributed around the support stud of the mirror. Thus, the mirror of the device is no longer held by a frame at its end portion, but only by a support stud substantially centered on the mirror.

This specific arrangement allowing the mirror to tilt substantially relative to its center, in particular makes it possible to present a maximum angle of inclination greater than that which can be obtained under similar operating conditions, with a conventional reflection device such as that described above. above.

However, the problem of sudden plating of the mirror on the substrate remains, so that it is still not possible, after having exceeded the supply voltage limit value, to maintain the mirror in a stable position other than that in which it is in contact with the substrate. In this regard, it is specified that even if the position of the mirror resting against the substrate can provide a large angle of inclination, it is however not desirable in the sense that the mirror can be caused to deform, and consequently cause a loss and / or distortion of a signal to be transmitted. Furthermore, it should be noted that the design of a mirror having optical properties necessary for good light reflection and mechanical properties preventing any deformation when it is pressed against the substrate, generates costs and / or constraints. significant footprint.

STATEMENT OF THE INVENTION

The object of the invention is therefore to propose a device for orienting an object such as a mirror, comprising a substrate, an object, as well as at least one support pin for the object interposed between the latter and the device substrate, the device further comprising electrostatic actuating means capable of moving the object in a plurality of positions relative to the substrate, the device at least partially overcoming the drawbacks mentioned above relating to the embodiments of the art prior.

To do this, the invention relates to a device for orienting an object such as a mirror, comprising a substrate, an object, as well as at least one stud for supporting the object interposed between the latter and the substrate. of the device, the device further comprising electrostatic actuation means capable of moving the object in a plurality of positions relative to the substrate, the electrostatic actuation means comprising a first and a second at least partially electrically conductive assembly intended to cooperate with each other in order to move the object in any one of the positions relative to the substrate, the first assembly being integral with the substrate. According to the invention, the second assembly is arranged between the substrate and the object, and the device further comprises a lower support stud located between the second assembly and the substrate and being integral with this second assembly and this substrate, thus an upper support stud located between the second set and the object and being integral with this second set and the object. In addition, the second assembly is able to be pressed against the substrate when the electrostatic actuation means are in an activated state.

Advantageously, when the object to be oriented or "deflected" is of the mirror type, the second set of electrostatic actuation means is no longer constituted by an internal conductive wall of the mirror, but takes the form of an assembly independent of the mirror, located at a distance from the latter, and attached integrally to the lower and upper support pads of the device. In this way, the displacement of the second assembly obtained by the activation of the electrostatic actuation means and authorized by a deformation of the lower support stud, makes it possible to generate a movement of the upper support stud, and consequently causes a displacement of the device mirror. As such, the particular arrangement according to the invention allows a strong inclination of the mirror relative to the substrate, without this state of steep inclination corresponding to a position in which the mirror is pressed against the substrate of the device. Indeed, during a movement of the mirror caused by the displacement of the second assembly, the latter is designed to come into contact with the substrate and stop the movement of the mirror, before the latter comes to bear against this same substrate.

Thus, the mirror of the device is then able to occupy stable positions of strong inclination in which its lower part is very close to the substrate, without however being in abutment against the latter. It is specified that this type of position was naturally not possible with the devices of the prior art, due to the pull-in phenomenon occurring between the conductive internal wall of the mirror and the electrodes located on the device substrate. In addition, it is noted that the second assembly is advantageously capable of describing a movement close to that of a ball joint, insofar as it is connected to the substrate via the lower support stud.

Furthermore, it is also indicated that when the mirror occupies a position of strong inclination, it is not pressed against another element of the device, but always remains only carried by the upper support stud to which it is secured. In this way, it does not deform and does not cause loss and / or distortion of a signal to be transmitted. In this regard, note that it is then possible to decouple the mechanical properties from the properties optics of the device, insofar as these properties are respectively provided by two distinct elements.

On the other hand, the specific positioning of the second assembly makes it possible to have a small distance between the latter and the substrate, while ensuring high inclinations of the mirror. Thus, the distance between the first and second at least partially electrically conductive assemblies constituting the electrostatic actuation means is also relatively small, and in any case less than the distance between the first assembly and the internal wall of the mirror of the device. Advantageously, the supply voltage required by the actuating means to generate a given inclination of the mirror can therefore be reduced compared to that which would have been necessary with a reflection device of the prior art, using the internal wall of the mirror. as a conductive element belonging to the actuating means.

Finally, it is indicated that the second assembly being intended to come into contact with the substrate of the device and consequently likely to stop the movement of the mirror before it comes to abut against this substrate, the device according to the invention offers the possibility it is up to this mirror to occupy discrete positions and also to avoid enslavement and / or to limit the enslavement time by pre-positioning. Preferably, the lower and upper support pads jointly form a single support stud passing through the second set and being integral with the latter, the single support stud having a first end secured to the substrate, as well as a second end secured to the object.

According to a first preferred embodiment of the present invention, the first fully conductive assembly consists of a plurality of electrodes spaced from each other and distributed around the support stud, these electrodes preferably being arranged so as to define a ring surrounding a single support stud. Of course, the distribution of the electrodes on the substrate is carried out as a function of the various positions which it is desired to occupy for the object of the device, each of these electrodes being able to cooperate with the second assembly taking the form of a plate. rigid, at least the bottom wall facing the plurality of electrodes is electrically conductive. In this first preferred embodiment, the activation of an electrode causes an end portion of the rigid plate to be pressed against the substrate of the device, as well as a sharp inclination of the object along a given axis. The plating observed then has the consequence of bringing the plate considerably closer to the electrodes adjacent to that which caused this plating, insofar as the rigid plate also rests in an inclined position, substantially parallel to the object. However, to generate a plating between an electrode and the rigid plate, the voltage the supply to be applied between these two elements is all the smaller the less the distance separating them. Thus, it is advantageously possible to implement relatively low supply voltages to press the plate against the substrate at the level of the adjacent electrodes, and therefore to cause a change of positioning to the object.

According to a second preferred embodiment of the present invention, the first assembly remains identical to that encountered in the first preferred embodiment, while the second assembly is a flexible membrane having a conductive bottom wall located opposite the plurality electrodes of the first set. Of course, it can therefore be a membrane produced entirely using an electrically conductive material such as monocrystalline silicon or polycrystalline silicon, or a membrane made of any flexible material, having a conductive coating constituting its lower wall. Another example could also consist in providing an electrically conductive coating on the upper wall of a support material, then used as an insulator. On the other hand, an alternative solution more complicated to implement could consist in providing a plurality of electrodes mounted on a membrane made of any flexible material, and arranged so as to be able to cooperate with the plurality of electrodes of the first set electrostatic actuation means. In addition, it is indicated that after having caused the flexible membrane to be pressed against any electrode, the plated portion of the membrane is extended on either side circumferentially by a deformed portion very close to the electrodes directly adjacent to that having been activated. However, to generate a plating between an electrode and the flexible membrane, as mentioned previously, the supply voltage to be applied between these two elements is all the smaller the less the distance separating them. Thus, it is advantageously possible to use relatively low supply voltages to press the deformed portion close to the adjacent electrodes against the substrate, and therefore to cause a change in positioning of the object.

According to a third preferred embodiment of the present invention, the second set remains identical to that encountered in the second preferred embodiment, while the first set always consists of a plurality of electrodes spaced from each other and distributed around the support pad, but arranged so as to define a plurality of concentric rings surrounding the support pad.

Advantageously, in addition to the possibility of obtaining a large inclination of the object relative to the substrate of the device, this preferred embodiment makes it possible to gradually and very precisely incline this object, by carrying out a plating of variable surface of the flexible membrane against the substrate.

In fact, for example, when an electrode of a ring is energized, the flexible membrane is automatically pressed against the substrate and causes a certain inclination of the object by deformation and / or displacement of the support stud. . Thus, from this instant, it is possible to actuate an electrode located nearby on the ring directly and internally adjacent, in order to increase the plating surface of the membrane, and therefore simultaneously increase the inclination l object relative to the substrate. Furthermore, it is noted that each of the positions of the object is obtained by abutment of the flexible membrane on the substrate of the device, which naturally ensures exact and precise positioning of this object.

In addition, it is indicated that a portion of the membrane pressed against the substrate extends not only on either side circumferentially by a deformed portion, but also radially by another deformed portion, also very close to the electrodes directly adjacent to the one having been actuated and belonging to an internally adjacent ring. Thus, it is advantageously possible to implement relatively low supply voltages to press the deformed portion close to the adjacent electrodes against the substrate, and therefore to accentuate the inclination of the object, until a very large inclination is obtained. of it. Finally, in this third preferred embodiment of the invention, the variation in the angle of inclination of the object as a function of the voltage applied to the electrostatic actuation means has a certain linearity, insofar as electrodes having the same surface can cause a linear displacement according to the number of activated electrodes.

According to a fourth preferred embodiment of the present invention, the flexible membrane constituting the second assembly is similar to that provided in the second and third preferred embodiments, but is additionally divided into a plurality of radial tongues each extending from the device's support pad. This configuration advantageously makes it possible to further increase the flexibility of the flexible membrane, and to significantly reduce the response time of the device. In all of the preferred embodiments described above, the object can then be in a substantially circular shape in the same way as the flexible membrane and the rigid plate, this shape being specially suitable for cooperating with the plurality of electrodes of the first set, arranged so as to define one or more rings surrounding the tilting member.

In addition, the preferentially flexible support stud is arranged substantially perpendicular to the substrate, to the object and to the flexible membrane or to the rigid plate of the device, when the electrostatic actuating means are in an inactivated state. Furthermore, this stud located substantially centered or substantially eccentrically on the object and on the flexible membrane or the rigid plate of the device, has a height of the order of 20 μm and a diameter which can vary depending on the nature of the materials, for example less than approximately 5 μm in the case of silicon.

According to a fifth and a sixth preferred embodiments of the present invention, the reflection device is in the form of any of the preferred embodiments mentioned above, and is produced so that at least one of the first and second sets has at least one priming zone. Thus, the supply voltage to be applied between electrically conductive elements to cause their plating being the smaller the greater the plating surface, the presence of one or more initiation zones of relatively large surface makes it possible to further lower the power requirements of the device.

All of the preferred embodiments briefly described above each have a single support pad forming both the lower support pad and the upper support pad, this single pad therefore extending from the substrate to the mirror of the device crossing the second set. However, provision can be made for these lower and upper studs to be distinct and separated from each other by the second set. In such a configuration, the device then comprises a lower support stud having a first end secured to the substrate as well as a second end secured to the second assembly, and an upper support stud having a first end secured to the second set as well as a second end secured to the object.

Advantageously, when the lower and upper studs are provided so as to be distinct, the manufacture of the orientation device can be considerably simplified and the maintenance of the object appreciably improved.

It is then possible to provide that the upper support stud is located in the extension of the lower support stud from which it is separated by the second set. Preferably, the upper support stud has a cross section substantially identical to that of the lower support stud, or else a cross section greater than that of this lower support stud.

Alternatively, the upper support stud can also be located eccentrically with respect to this same lower support stud.

Other advantages and characteristics of the invention will appear in the detailed non-limiting description below.

BRIEF DESCRIPTION OF THE DRAWINGS

This description will be made with reference to the accompanying drawings in which: - Figure 1 shows a sectional view of an object orientation device according to a first preferred embodiment of the present invention, when the electrostatic actuation means are in an inactivated state,

- Figure 2 shows a sectional view taken along line II-II of Figure 1, Figure 3 shows the device for orienting an object of Figure 1, when the electrostatic actuation means are in an activated state, - Figure 4 shows a sectional view of an object orientation device according to a second preferred embodiment of the present invention, when the electrostatic actuation means are in an inactivated state, - FIG. 5 represents the device for orienting an object of FIG. 4, when the electrostatic actuation means are in an activated state,

FIG. 6 represents a sectional view of a device for orienting an object according to a third preferred embodiment of the present invention, when the electrostatic actuation means are in an inactivated state,

- Figure 7 shows a sectional view taken along line VII-VII of Figure 6, Figure 8 shows the device for orienting an object of Figure 6, when the electrostatic actuation means are in an activated state, - Figure 9 shows the orientation device of an object of Figure 6, when the electrostatic actuating means are in another activated state,

FIG. 10 partially represents a top view of an object orientation device according to a fourth preferred embodiment of the present invention, when the electrostatic actuation means are in an inactivated state,

- Figure 11 shows a sectional view of an object orientation device according to a fifth preferred embodiment of the present invention, when the electrostatic actuating means are in an inactivated state, and when the zones d are in an activated state,

FIG. 12 represents a sectional view taken along line XII-XII of FIG. 11,

- Figure 13 shows a partial top view of an object orientation device according to a sixth preferred embodiment of the present invention, when the electrostatic actuating means are in an inactivated state, and when the area boot is also in an activated state, Figures 14 to 17 show variants of the orientation device according to the first preferred embodiment, shown in Figures 1 to 3, and Figures 18a to 18k schematically represent the different steps of an example of a method for manufacturing an object orientation device according to the invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

It is first indicated that in the preferred embodiments described below, the orientation devices of an object according to the invention are all assimilated to light reflection devices, in which the object to be oriented is a mirror. However, of course, other types of objects could be used in place of the mirror, such as an optical lens, ^a series of optical lenses, or a deformable mirror, within the scope of the invention.

With reference jointly to Figures 1 and 2, there is shown a device 1 for orienting an object, according to a first preferred embodiment of the present invention.

The device 1 firstly comprises a substrate 2, for example made of silicon, as well as a mirror 4 kept at a distance from the substrate 2, substantially parallel to the latter. The mirror 4 preferably has a substantially circular shape, but could of course adopt any other suitable shape, without departing from the scope of the invention. In addition, it is specified that the mirror 4 has a diameter of the order of 400 μm and a thickness of approximately 5 μm, and is preferably produced conventionally using materials such as aluminum. .

In order to keep the mirror 4 away from the substrate 2, the device 1 also includes a single support pad 6 for the mirror 4, interposed between the latter and the device substrate 2. Like this will be explained more clearly below, the single support stud 6 constitutes both a lower support stud 6 ′, as well as an upper support stud 6 ". Preferably, the support stud 6 is made of silicon, and has a height of the order of 20 μm and a diameter of less than approximately 5 μm in the case of the use of silicon.

As can be seen in FIG. 1, the support stud 6 is provided with a first end 6a and with a second end 6b, the first end 6a being integral with the substrate 2 and the second end 6b being integral with the mirror 4 .

The orientation device 1 further comprises electrostatic actuation means capable of moving the mirror 4 in a plurality of positions relative to the substrate 2, each of these positions making it possible to reflect a light beam in a distinct direction. The electrostatic actuation means comprise a first assembly 8 and a second assembly 10, each of them being designed to cooperate with the other in order to cause a displacement of the mirror 4 in one of the positions relative to the substrate 2 , and being at least partially electrically conductive.

Still with reference to FIGS. 1 and 2, it can be seen that the lower support stud 6 ′, formed by a part of the single stud 6, is located between the substrate 2 and the second assembly 10. In addition, this lower support stud 6 '' integral with both the substrate 2 and of the second set 10 carries the first end 6a of the single stud 6. In the same way, the upper support stud 6 '', formed by another part of the single stud 6, is located between the second set 10 and the object 4. In addition, this upper support stud 6 '' integral with both the second assembly 10 and the object 4 carries the second end 6b of the single stud 6.

Consequently, it can be seen that the lower 6 'and upper 6' 'support studs are in fact joined in the form of a single support stud 6 passing through the second assembly 10 and being secured to the latter, and s extending from the substrate 2 to the object 4.

In this first preferred embodiment, the first assembly 8 is integral with the substrate 2, and is constituted by a plurality of electrodes 12 spaced from one another and distributed around the support stud 6, the distribution being judiciously carried out according to the specific positions which it is desired to have the mirror 4 of the device take 1. Preferably, the electrodes 12, located on an upper part of the substrate 2 and covered by an insulating film 14, are arranged so as to define a ring 12a surrounding the stud support 6, while remaining circumferentially spaced from each other. Of course, the arrangement of the electrodes 12 could be quite different, for example adapted so that these electrodes 12 define a square, without departing from the scope of the invention. In addition, they are each connected to an electrical power source (not shown), and made of a conventional conductive material such as a metal or doped silicon, and isolated from each other using a conventional insulating element such as air or an oxide. Furthermore, in this first preferred embodiment of the present invention, the second set 10 of the electrostatic actuation means takes the form of a rigid plate at least partially electrically conductive 16, integral with the support stud 6 and located at a distance substrate 2 and mirror 4. As such, note that the plate 16 can be made entirely using an electrically conductive material such as silicon, aluminum and gold, or have only one conductive lower or upper wall 16a.

Consequently, the plate 16, also connected to the electric power source, is free relative to the mirror 4, insofar as no direct mechanical connection exists between these two elements.

On the other hand, when the electrostatic actuating means are in an inactivated state as shown in FIG. 1, that is to say when the supply voltage applied between the first and second sets 8 and 10 by the electric power source is substantially zero, the plate 16 then rests substantially parallel to the substrate 2 and to the mirror 4 of the device 1.

Preferably, the plate 16 is also of substantially circular shape, and has a diameter slightly smaller than that of the mirror 4, and slightly higher than that of the ring 12a formed by the electrodes 12 of the first set 8.

It is further noted that in this first preferred embodiment as well as in all the other preferred embodiments described below, the single support stud 6 can be located either centrally or eccentrically on the mirror 4 and the second assembly 10 of the device 1. With reference to FIG. 3, one can see the orientation device 1 according to the first preferred embodiment of the present invention, when the electrostatic actuation means are in an activated state, that is to say when a certain supply voltage is applied between the plate 16 and one or more electrodes 12 of the first set 8.

As can be seen in this FIG. 3, the supply voltage applied to the electrostatic actuation means causes the rigid plate 16 to be pressed against the substrate 2, this pressing taking the form of a contact between an end portion of the plate 16, and a part of the substrate 2 located in line with the activated electrode or adjacent electrodes 12. Thus, the movement of the rigid plate 16 generates a deformation of the support stud 6, preferably made of a flexible material. Naturally, the support stud 6 could be rigid and assembled on the substrate 2 using an appropriate mechanical connection allowing pivoting of stud 6 along all of the required axes, without departing from the scope of the invention.

Consequently, the movement of the rigid plate 16 causing the deformation or displacement of the support stud 6 also generates a movement of the mirror 4 relative to the substrate 2, this movement being stopped by the coming into contact of the plate 16 and the substrate 2 In such a configuration, the mirror 4 can therefore be strongly inclined relative to the substrate 2, without being in abutment against the latter.

Furthermore, it is specified by way of example that when the device 1 is in an activated state such as that shown in FIG. 3, in which an electrode 12 is activated, it is then possible to modify the positioning of the mirror 4 by activating an adjacent electrode 12. In this case, the distance between the adjacent electrode 12 and the rigid plate 16 is very small due to the initial inclination of the plate 16, and the supply voltage to be applied between the electrode adjacent 12 and the plate 16 to cause a change in the axis of inclination of the mirror 4 is therefore advantageously unimportant.

Referring to Figures 4 and 5, there is shown a device 100 for orienting an object, according to a second preferred embodiment of the present invention.

It is first indicated that the elements of the device 100 shown in Figures 4 and 5 bearing the same reference numerals as elements of the device 1 shown in Figures 1 to 3, correspond to identical or similar elements.

As such, we see that the orientation device 100 comprises a substrate 2, a mirror 4, a support pad 6 and. a first set 8, all of these elements being arranged in a similar manner to that encountered in the first preferred embodiment.

Thus, the first set 8 of the electrostatic actuation means comprises a plurality of electrodes 12 spaced from each other and covered by an insulating film 14, these electrodes 12 being distributed on the substrate 2 around the support stud 6, so defining a ring 12a as shown in FIG. 2. In addition, they are each connected to an electrical power source (not shown), and made of a conventional conductive material such as a metal or doped silicon, and isolated from each other using a conventional insulating element such as air or an oxide.

In this second preferred embodiment of the present invention, the electrostatic actuation means also comprise a second electrically conductive assembly 110, integral with the support stud 6 and located at a distance from the substrate 2 and the mirror 4.

Unlike the second set 10 of the device 1 according to the first preferred embodiment, the second set 110 of the device 100 takes the form of a flexible membrane 116, having a bottom wall 116a electrically conductive. Preferably, the flexible membrane 116 is entirely produced using an electrically conductive material such as monocrystalline silicon or polycrystalline silicon. Of course, this membrane 116 is also connected to the electrical power source, and is free relative to the mirror 4, insofar as no direct mechanical connection exists between these two elements.

On the other hand, when the electrostatic actuating means are in an inactivated state such as that shown in FIG. 4, that is to say when the supply voltage applied between the first and second sets 8 and 110 by the electric power source is substantially zero, the membrane 116 then rests substantially parallel to the substrate 2 and to the mirror 4 of the device 100.

Preferably, the membrane 116 is also of substantially circular shape, and has a diameter slightly less than that of the mirror 4, and slightly greater than that of the ring 12a formed by the electrodes 12 of the first set 8.

Referring to Figure 5, we can see the orientation device 100 according to the second preferred embodiment of the present invention, when the electrostatic actuating means are in an activated state, that is to say when a certain supply voltage is applied between the membrane 116 and one or more electrodes 12 of the first set 8. As can be seen in this FIG. 5, the supply voltage applied to the electrostatic actuation means causes a plating of the flexible membrane 116 against the substrate 2 of the device 100. This plating takes the form of a flat contact between a portion 118 of the membrane 116 initially located opposite the activated electrode or adjacent electrodes 12, and a part of the substrate 2 situated in line with this activated electrode or electrodes 12. Thus, the movement of the flexible membrane 116 generates a deformation of the support stud 6, and consequently causes a movement of the mirror 4 relative to the substrate 2, this movement being stopped by the balance between the force of electrostatic attraction and the restoring force generated by the bending of the stud 6 and the bending of the membrane 116. In such a configuration, the mirror 4 can therefore be strongly inclined relative to the substrate 2, without being in abutment against the latter. Furthermore, it is specified by way of example that when the device 100 is in an activated state such as that shown in FIG. 5, in which an electrode 12 is activated, it is then possible to modify the axis of inclination of the mirror 4 by activating an adjacent electrode 12, and repeating this action as many times as necessary, in order to obtain an inclination of the mirror 4 along the desired axis. As such, it should be noted that the portion 118 of the membrane 116 pressed against the substrate 2 following the activation of an electrode 12 is extended circumferentially on either side by a deformed portion 120 (only one of them being shown), very close to the electrodes 12 directly adjacent to that which has been actuated.

Thus, the distance between the adjacent electrode 12 and the deformed portion 120 is very small, and the supply voltage to be applied between the adjacent electrode 12 and the flexible membrane 116 to cause a change in position of the mirror 4 is therefore advantageously unimportant. With reference to Figures 6 and

7, there is shown a device 200 for orienting an object, according to a third preferred embodiment of the present invention.

It is first indicated that the elements of the device 200 shown in Figures 6 to 9 bearing the same reference numerals as elements of the devices 1 and 100 shown in Figures 1 to 5, correspond to identical or similar elements. As such, we can see that the orientation device 200 comprises a substrate 2, a mirror 4, a support pad 6 and a second assembly 110, all of these elements being arranged in a similar manner to that encountered in the first and second preferred embodiments.

Thus, the second set 110 of the electrostatic actuation means is constituted by a flexible membrane 116, having a bottom wall 116a electrically conductive. Preferably, the flexible membrane 116 is entirely made using an electrically conductive material such as monocrystalline silicon or polycrystalline silicon. In addition, this membrane 116 is connected to an electrical power source (not shown), and is free relative to the mirror 4, insofar as no direct mechanical connection exists between these two elements.

The first assembly 208 of the device 200 takes the form of a plurality of electrodes 212 spaced from one another and distributed around the support stud 6, the distribution being judiciously carried out as a function of the specific positions that it is desired to take at the mirror 4 of the device 1. The electrodes 212, located on an upper part of the substrate 2 and covered by an insulating film 14, are arranged so as to define a plurality of concentric rings 212a, 212b, 212c, 212d surrounding the support stud 6, while remaining spaced circumferentially and radially from each other. In addition, they are each connected to the electrical power source, and made of a conventional conductive material such as a metal or doped silicon, and isolated from each other using a conventional insulating element such as air or an oxide. When the electrostatic actuation means are in an inactivated state such as that shown in FIG. 6, that is to say when the supply voltage applied between the first and second sets 208 and 110 by the power source is substantially zero, the membrane 116 then rests substantially parallel to substrate 2 and to mirror 4 of device 200.

With reference to FIG. 8, one can see the orientation device 200 according to the third preferred embodiment of the present invention, when the electrostatic actuating means are in an activated state, that is to say when a certain supply voltage is applied between the membrane 116 and one or more electrodes 212 of the first set 208. Note that in the configuration shown, only one or more electrodes 212 of the ring 212a having the largest diameter have been actuated.

The supply voltage applied to the electrostatic actuation means causes the flexible membrane 116 to be pressed against the substrate 2 of the device 200. As indicated in the second preferred embodiment, this pressing takes the form of a plane contact between a portion 118 of the membrane 116 initially located opposite the activated electrode or adjacent electrodes 212 of the same ring 212a, and a part of the substrate 2 located at the right of this electrode or these activated electrodes 212. Note that as can be seen in FIG. 8 that the plated portion 118 constitutes a peripheral portion of the flexible membrane 116.

Thus, the movement of the flexible membrane 116 generates a deformation of the support stud 6, and consequently causes a movement of the mirror 4 relative to the substrate 2, this movement being stopped by the coming into contact of the membrane 116 and the substrate. 2. In such a configuration, the mirror 4 can therefore be slightly inclined relative to the substrate 2.

As indicated above in the second preferred embodiment, it is easily possible to change the tilt axis of the mirror 4 by actuating an adjacent electrode 212 of the same ring 212a, using a voltage relatively low power supply allowed by the small distance existing between this adjacent electrode 212 and the deformed portion 120 circumferentially extending the plated portion 118 of the membrane 116.

Furthermore, note that when the device 200 is in an activated state such as that shown in FIG. 8, in which an electrode 12 is activated, it is then possible to modify the positioning of the mirror 4 by activating an adjacent electrode 212 belonging to the ring 212b directly and internally adjacent. In this case, as can be seen in FIG. 9, the axis of inclination of the mirror 4 remains substantially unchanged, while the angle formed between this mirror 4 and the substrate 2 is then slightly accentuated, due to d 'greater deformation of the flexible membrane 116. In fact, the plated portion 118 of the membrane 116 extends over two electrodes 212 belonging to two adjacent rings 212a and 212b, which causes a simultaneous increase on the one hand plating surface between the membrane 116 and the substrate 2, and on the other hand the deformation of the support stud 6. In this way, by repeating the action described above for each of the remaining electrode rings 212c and 212d, it is possible to gradually vary the angle of inclination of the mirror 4 relative to the substrate 2, by constantly passing by stable and precise positions, ensured by the abutment of the flexible membrane 116 against the substrate 2. As such, it should be noted that the portion 118 of the membrane 116 pressed against the substrate 2 following the activation of 'An electrode 212 is extended radially by another deformed portion 122, also very close to the electrodes 212 directly adjacent to that having been actuated, and belonging to the ring 212b directly and internally adjacent to the ring 212a.

Thus, here again, the supply voltage to be applied between the adjacent electrode 212 and the flexible membrane 116 to cause a change in the angle of inclination of the mirror 4 is consequently advantageously unimportant. In addition, the deformed part 122 progressively moving towards the support stud 6 of the device 200 as the different rings are actuated, the supply voltage to be applied to the electrostatic actuation means always remains low, even in the case where the angle of inclination of the mirror 4 is very high.

Finally, it is indicated that with such a reflection device 200, the mirror 4 is able to be inclined at an angle of the order of ± 10 ° relative to the substrate 2, using a voltage d 'food electrostatic actuation means less than about 100 V.

Referring to Figure 10, there is partially shown a device 300 for orienting an object, according to a fourth preferred embodiment of the present invention.

It is first indicated that the elements of the device 300 shown in Figure 10 bearing the same reference numerals as elements of the devices 100 and 200 shown in Figures 4 to 9, correspond to identical or similar elements.

As such, It is specified that the device 300 can take the form of any of the devices 100 and 200 according to the second and third preferred embodiments, with the difference that the flexible membrane 116, constituting the second assembly 110 electrically conductor, is divided into a plurality of radial tabs 116a. In the configuration shown in FIG. 10 where the device 300 is similar to the orientation device 200 according to the third preferred embodiment of the invention, the tongues 116a each extend from the support stud 6, and cover a plurality electrodes 212 each belonging to a different ring 212a, 212b, 212c, 212d. Of course, in the case not shown where the device 300 has a first assembly 8 comprising electrodes 12 defining a single ring 12a such as that shown in FIG. 2, each of the radial tongues 116a covers a single electrode 12.

In this way, the flexibility of the flexible membrane 116, provided by its fragmentation into several _^ tabs 116a, has the effect of considerably reducing the response time of the 300 reflection device, so that various changes in positioning of the mirror 4 (not shown) can be operated more quickly. As an indication, in order to take advantage of the same advantages, the flexible membrane 116 could be replaced by one or more bars.

(not shown), each assembled on the single support pad 6. With reference jointly to Figures 11 and 12, there is shown a device 400 for orienting an object, according to a fifth preferred embodiment of the present invention .

It is firstly indicated that the elements of the device 400 represented in FIGS. 11 and 12 bearing the same numerical references as elements of the devices 1, 100, 200 and 300 represented in FIGS. 1 to 10, correspond to identical elements. or the like. As such, it is specified that the orientation device 400 can take the form of any of the devices 1, 100, 200 and 300 according to the first four preferred embodiments described above, with the difference that the first and second at least partially electrically conductive assemblies each further include a zone boot. Of course, the first and second assemblies could also each comprise several initiation zones, without departing from the scope of the invention. In the configuration shown in FIG. 10 where the orientation device 400 is similar to the orientation device 200 according to the third preferred embodiment of the invention, it can be seen that the second assembly 110 comprises the flexible membrane 116, as well as a priming area 420.

The initiation zone 420 is substantially circular, and attached to an end portion of the membrane 116, so as to extend beyond the latter.

Furthermore, the first assembly 208 further comprises a priming zone 422 also substantially circular and of the same dimension as the priming zone 420, located in the same plane as the electrodes 212, and arranged outside them. In addition, the initiation zones 420 and 422 are placed opposite one another, so that when a supply voltage is applied to them, the initiation zone 420 is pressed against the substrate 2 of the device. 400, as shown in Figure 11.

Thus, by using such priming zones 420 and 422 whose surfaces are much greater than that of the electrodes 212 of the first set 208, the supply voltage to be applied between these zones to cause their plating is therefore only very low. Furthermore, it should be noted that the main function of the plating observed is to cause a slight deformation of the flexible membrane 116, so that the latter approaches the ring of electrodes 212a having the largest diameter. In this way, unlike the various cases encountered in the previous preferred embodiments, the initial supply voltage to be applied between the membrane 116 and a first electrode 212 of the ring 212a is also very low.

Thus, with such a reflection device 400, whether it is to press the initiation zones 420 and 422, press the flexible membrane 116 against a first electrode 212 of the ring 212a having the largest diameter, accentuate the inclination of the mirror 4 by pressing the membrane 116 against an electrode 212 of an inner ring 212b, 212c or 212d, change the axis of inclination of the mirror 4 by pressing the membrane 116 against an adjacent electrode 212 of the same ring 212a, the voltage d The required power is always relatively low, and the source of electrical power considerably simplified.

Referring to Figure 13, there is shown a device 500 for orienting an object, according to a sixth preferred embodiment of the present invention, constituting an alternative to the device 400 according to the fifth preferred embodiment.

Thus, in the same way as previously, the elements of the device 500 shown in FIG. 13 bearing the same numerical references as elements of the devices 1, 100, 200 and 300 shown in FIGS. 1 to 10, correspond to identical or similar elements.

As such, it is specified that the orientation device 500 can take the form of any one of the devices 1, 100, 200 and 300 according to the first four preferred embodiments described above, with the difference that the first electrically conductive assembly further comprises a priming zone.

In the configuration shown in FIG. 13 where the orientation device 500 is similar to the orientation device 200 according to the third preferred embodiment of the invention, it can be seen that the first assembly 208 comprises the plurality of electrodes 212, as well as a priming zone 522.

In the same way as certain electrodes 212, the initiation zone 522 partially constitutes the ring 212a having the largest diameter, and therefore takes the form of a surface electrode much greater than the other electrodes 212 of the first set 208, in since it constitutes a real angular portion of the ring 212a. Thus, as in the fifth preferred embodiment, by using such a priming zone 522, the supply voltage to be applied between this zone 522 and the flexible membrane 116 to cause the plating thereof is not therefore only very small, the plating observed having the main function of causing a deformation of the flexible membrane 116, so that it approaches the electrodes 212 of the rings 212a and 212b.

Furthermore, it is indicated that the second assembly 110 is electrically connected by means of holding arms 524 which are electrically conductive. The holding arms 524 are preferably designed so as to be extremely flexible, so that they have almost no resistance to the movement of the assembly 110 caused by the electrostatic actuation.

Referring to Figures 14 to 17, there are shown variants of the first preferred embodiment of the present invention. It is specified that these variants in which the orientation device 1 has lower and upper support studs distinct and separate from each other are only described in the case of the first preferred embodiment of the present invention, but could of course apply to any other preferred embodiment described above, without departing from the scope of the invention.

Thus, firstly with reference to FIG. 14, we see a first variant in which the device 1 comprises a single lower support stud 6 'establishing the junction between the substrate 2 and the second assembly at least partially electrically conductive 10. Indeed, the lower support stud 6 'has a first end 6' a secured to the substrate 2, as well as a second end 6'b secured to the second assembly 10. Furthermore, the device 1 also includes a single upper support stud 6 '', located in the extension of stud 6 'and having substantially the same section. As can be seen in this figure 14, the upper support stud 6 '' is fixedly arranged between the second set 10 and the mirror 4, and therefore has a first end 6 '' a secured to the second set 10, thus as a second end 6''b secured to the object 4.

With such an assembly in which the two superimposed pads 6 'and 6''are distinct and separated by the second electrically conductive assembly 10, the manufacture of the orientation device 1 is significantly simplified compared to the manufacture of a device similar whose single support stud 6 extends integrally between the substrate and the mirror by jointly forming the lower and upper support studs, and around which it is necessary to secure the second conductive assembly (Figure 1). FIG. 15 shows another variant in which the single upper support stud 6 '' is arranged eccentrically with respect to the single lower support stud 6 ', the studs 6' and 6 '' preferably having the same section. Thus, it is possible to obtain both a rotation of the mirror 4 via the lower support stud 6 ', and / or a translation of this mirror 4 along a longitudinal axis (not shown) of the upper support stud 6 '', for example by means of a movement device (not shown) mounted on this same support stud 6 ''. Still in the case where the orientation device 1 only has a single lower support stud 6 'and a single upper support stud 6'', with reference to FIG. 16, provision can be made for the stud 6 'has a section smaller than that of the stud 6'', these two studs 6' and 6 '' being arranged so as to be substantially in the extension of one another. In this way, it is possible to ensure good retention of the mirror 4 on the stud 6 '' thanks to the relatively large section of the latter, while allowing good bending of the lower stud 6 'by providing it with a smaller section. .

Finally, as can be seen in FIG. 17, provision can be made for the device 1 to comprise a single lower support stud 6 ', and a plurality of upper support studs 6' 'integral with the mirror 4 and the second set 10 In this FIG. 17, by way of illustrative example, two upper studs 6 ″ have been shown, of section substantially identical to that of the lower stud 6 ′. Advantageously, these two studs 6 '', for example placed on either side of the lower stud 6 ', allow better sealing between the mirror 4 and the second set at least partially electrically conductive 10.

An example of a method for manufacturing an object orientation device according to the invention will now be described. Referring to Figure 18a, the first step in this manufacturing process is to plan a substrate 601 of the SOI substrate type (from the English “Silicon On Isolant”, the substrate 601 being composed of a lower layer of silicon 602 as well as an upper layer of silicon 604, these two layers being separated by a film 606 made of silicon oxide.

As can be seen in FIG. 18b, the upper layer 604 is etched in order to reveal a support stud 608.

Then, there are implanted electrodes 610 in the lower layer 602, as well as tracks intended to connect the electrodes to the electric poles situated outside the device, this operation being carried out in particular by providing a layer of resin 611 deposited on the film. 606, on the support pad 608, as well as on the rest of the upper layer 604 (FIG. 18c). As an indication, it is specified that the purpose of the resin layer 611 is to protect the areas not intended to be implanted.

With reference to FIG. 18d, the film 606 serving as implantation oxide is then removed by deoxidation, then replaced by an insulating film 612, covering the lower layer 602, the electrodes 610, the support pad 608, as well as the rest of the upper layer 604. Subsequently, as shown in FIG. 18e, a molecular sealing of a thin layer of silicon 614 is carried out, on the insulating film 612, above the support pad 608 and the rest of the upper layer 604 of the substrate 601. As can be seen in the figure

18f, it is then possible to engrave this thin layer 614 made of silicon, in order to obtain holding arms 616, as well as electrodes (not shown), arranged opposite the electrodes 610 secured to the lower layer 602 of the substrate 601. It should also be noted that the holding arms 616 can be used to power the electrodes etched on the thin layer of silicon 614.

Simultaneously with the preceding operations represented in FIGS. 18a to 18f, the method of manufacturing the device for orienting an object comprises a step consisting in providing another substrate 618, also of the SOI substrate type, the substrate 618 being composed of a lower layer of silicon 620 as well as an upper layer of silicon 622, these two layers being separated by a film 624 of silicon oxide (FIG. 18g).

As can be seen in FIG. 18h, the upper layer 622 is then etched several times to reveal on the one hand a mirror 626, and on the other hand a support stud 628, integral with the mirror 626 and located above of it.

Subsequently, the substrate 618 is covered with a sealing oxide, taking the form of a film 630 deposited on the mirror 626, on the support pad 628, on the film 624, as well as on the rest of the upper layer. 622 of substrate 618, as shown in Figure 18i.

Once these two series of operations have been carried out, the substrate 618 can be turned over and sealed by adhesion to the substrate 601, so that the part of the film 630 covering the support pad 628 is in contact with the central part of the thin layer 614 of the substrate 601.

Finally, we can then proceed with the elimination of the lower layer 620 from the substrate 618, as well as that of the films 624 and 630 of this same substrate, for example using an RIE etching technique.

In this way, with reference to FIG. 18k, it is then possible to obtain a device for orienting an object such as a mirror, comprising a mirror 626, an upper support stud 628, a second electrically conductive assembly 614, a lower support pad 608, as well as a support 602 provided with electrodes 610 constituting the first electrically conductive assembly.

Of course, various modifications can be made by those skilled in the art to the orientation devices of an object 1, 100, 200, 300, 400, 500 which have just been described, only by way of nonlimiting examples.

Claims

1. Device (1,100,200,300,400,500) for orienting an object comprising a substrate (2), an object (4), as well as at least one support stud (6, 6 ', 6'') for the object ( 4) interposed between the latter and the substrate (2) of the device, said device further comprising electrostatic actuation means capable of moving the object (4) in a plurality of positions relative to said substrate (2), the means actuation actuator comprising a first (8,208) and a second assembly (10,110) at least partially electrically conductive intended to cooperate with each other in order to move the object (4) in any one of said positions relative to to the substrate (2), the first assembly (8,208) being integral with said substrate (2), characterized in that the second assembly (10,110) is arranged between the substrate (2) and the object (4), said device comprising at in addition to a lower support stud (6 ') located between said second assembly (10,110) e t the substrate (2) and being integral with said second assembly (10,110) and the substrate (2), as well as an upper support stud (6 '') located between said second assembly (10,110) and the object (4) and being integral with said second assembly (10,110) and with the object (4), said second assembly (10,110) being able to be pressed against the substrate (2) when the electrostatic actuation means are in an activated state.

2. Device (1,100,200,300,400,500) according to claim 1, characterized in that said lower and upper support pads (6 ', 6' ') jointly form a single support pad (6) passing through the second set (10,110) and being integral thereof, said single support stud (6) having a first end (6a) secured to the substrate (2), as well as a second end (6b) secured to the object (4).

3. Device (1,100,200,300,400,500) according to claim 2, characterized in that the first assembly (8,208) consists of a plurality of electrodes (12,212) spaced from each other and distributed around the single support pad (6 ).

4. Device (100,200,300,400,500) according to claim 3, characterized in that the second assembly (110) consists of a flexible membrane (116) having a conductive bottom wall (116a) located opposite said plurality of electrodes (12,212) constituting the first set (8,208).

5. Device (100,200,300,400,500) according to claim 4, characterized in that the support pad (6) is flexible.

6. Device (100,300,400,500) according to claim 4 or claim 5, characterized in that said plurality of electrodes (12) constituting the first set (8) electrically conductive and integral with the substrate (2) are arranged so as to define a ring (212a) surrounding the support stud (6).

7. Device (200,300,400,500) according to claim 4 or claim 5, characterized in that said plurality of electrodes (212) constituting the first assembly (208) electrically conductive and integral with the substrate (2) are arranged so as to define a plurality of concentric rings (212a, 212b, 212c, 212d) surrounding the support stud (6).

8. Device (100,200,300,400,500) according to any one of claims 4 to 7, characterized in that the flexible membrane (116) is divided into a plurality of radial tongues (116a) each extending from the support stud (6) of the device.

9. Device (100,200,300,400,500) according to any one of claims 4 to 8, characterized in that the support stud (6) is located substantially centered on the object (4) and on the flexible membrane (116) of the device.

10. Device (100,200,300,400,500) according to any one of claims 4 to 8, characterized in that the support stud (6) is located substantially eccentrically on the object (4) and on the flexible membrane (116) of the device.

11. Device (100,200,300,400,500) according to any one of claims 4 to 10, characterized in that the object (4) and the flexible membrane (116) each have a substantially circular shape.

12. Device (100,200,300,400,500) according to any one of claims 4 to 11, characterized in that the support stud (6) of the object (4) is arranged substantially perpendicular to the substrate (2), to the object ( 4) and to the flexible membrane (116) of the device, when the electrostatic actuation means are in an inactivated state.

13. Device (1,100,200,300,400,500) according to any one of claims 3 to 12, characterized in that the support stud (6) has a height of the order of 20 μm and a diameter less than about 5 μm .

14. Device (1,100,200,300,400,500) according to any one of the preceding claims, characterized in that at least one of the first and second sets (8,208,10,110) has at least one priming zone (420,422,522).

15. Device (1,100,200,300,400,500) according to claim 1, characterized in that said lower support stud (6 ') has a first end (6'a) integral with the substrate (2), as well as a second end ( 6'b) integral with the second assembly (10,110), and in that said support stud upper (6 '') has a first end (6 '' a) secured to the second assembly (10,110), as well as a second end (6''b) secured to said object (4).

16. Device (1,100,200,300,400,500) according to claim 16, characterized in that the upper support stud (6 '') is located in the extension of the lower support stud (6 ') from which it is separated by the second set (10,110) , and has a section substantially identical to that of this lower support stud (6 ').

17. Device (1,100,200,300,400,500) according to claim 15, characterized in that the upper support stud (6 '') is located in the extension of the lower support stud (6 ') from which it is separated by the second set (10,110) , and has a section higher than that of this lower support stud (6 ').

18. Device (1,100,200,300,400,500) according to claim 15, characterized in that the upper support stud (6 '') is located eccentrically with respect to the lower support stud (6 ').