WO2012089958A1

WO2012089958A1 - Optoelectronic device and method for determining bidimensional position

Info

Publication number: WO2012089958A1
Application number: PCT/FR2011/053073
Authority: WO
Inventors: Philippe Plantier; Claude N. BUREAU
Original assignee: H2I Technologies
Priority date: 2010-12-31
Filing date: 2011-12-20
Publication date: 2012-07-05
Also published as: FR2970096A1; FR2970096B1

Abstract

The invention relates to an optical and electronic system for determining a position of an object (2) present on a predefined surface (S), the system comprising at least one emitter (E) emitting a beam (F) covering the predefined surface (S) and exhibiting specific spectral and/or modulation characteristics making it possible to detect it including in the presence of a natural light of high intensity, this system comprising two devices (D1, D2) for detecting an angular direction (α1,α2) in which the object (2) lies and a module (10) for determining the position of the object (2) so as, knowing the position of the two devices (D1, D2) with respect to the predefined surface (S) and the angular direction (α1,α2) in which the object (2) lies with respect to each of the devices (D1,D2) for detecting an angular direction (α1,α2), to deduce therefrom the position of the object (2) on the predefined surface (S) by intersection of the predefined surface (S) and of the two angular directions (α1,α2) determined with respect to the detection devices (D1,D2).

Description

Title of the invention

"Optoelectronic device and method for two-dimensional position determination". Background of the invention

The present invention relates to the general field of optical and electronic systems for determining a position of an object present on a predefined surface.

Such systems can be used as a pointing device for the control of computer equipment or household appliances, to make the recognition of writing or gesture, etc.

The predefined surface can be real or virtual. The invention is more specifically concerned with systems comprising at least one transmitter disposed on a so-called transmission-side side of the predefined surface in order to emit a beam of radiation having spectral or specific modulation characteristics making it possible to detect this light even in the presence of high intensity natural light. This type of detection device belongs to the non-contact detection devices.

There are currently many principles to make a device capable of detecting, remotely, without detection with contact, the two-dimensional position of a finger.

Some devices use a plane of light and a camera. This is particularly the case in the document US 2007/0222760 which describes a data acquisition device, using a principle of image-sensing detection of a two-dimensional surface using elements placed on three dimensions.

According to this prior art, a visible or infrared light plane is generated. This plane of light covers the area in which the finger must be detected. A particular optical system makes it possible to form an image of the area illuminated by the plane of light on a two-dimensional image sensor. It is typically a camera.

If a user's finger crosses the generated light plane, he re-emits a part of this light to this sensor which forms an image whose position depends on the position of the finger. An analysis of the image obtained provides access to the angle at which the finger is viewed and the distance to which it is located.

As the sensor is two-dimensional, it is able not only to have access to the angle but also to the position of the finger relative to the imaged surface.

Many known devices thus use one- or two-dimensional imaging devices to locate an object. This principle makes it possible to obtain good accuracy, but these devices have a relatively high manufacturing cost and a complex mechanical integration. These prior art also have the disadvantage of having to require the implementation of expensive imaging components, especially a camera sensor and optics of sufficient quality to allow to have an image without deformation or aberration. The image processing electronics is also expensive since the operation of these devices requires a digital signal processor of the DSP type for "Digital Signal Processor" in English, powerful enough to be able to process the images and to extract the one or more finger positions.

In addition, the size of these devices of the prior art is quite important since the image sensor must be located in height relative to the predefined surface where is detected the position of the object or shifted on one side a line where the object is likely to be. This is necessary to have a sufficient angle to be able to see the whole surface or the whole line. The use of this technology is therefore incompatible with many mechanical constraints encountered in many areas.

In addition, these devices are not compatible with the principles of ambient light compensation of the type described in document FR 08 59048, these principles of light compensation being indispensable when the device must be able to be used outdoors and for detection on a free surface.

Known devices using imaging sensors therefore have limited applications since they can not operate outdoors or impose drastic implementation conditions of the type of a mechanical integration maintaining the sensor and the object to be detected at the same time. shadow. It is also known position sensors employing discrete components which, conversely, can overcome such limitations. The document FR 2 899 326 describes such a position detection device using a matrix of emitters and receivers arranged in a staggered arrangement. The device described is designed to operate on a principle using the ignition of a single transmitter and a plurality of directional receivers detecting the position of the object on the beam emitted by this transmitter. The emitters are therefore switched on sequentially.

When the object is close to the array of transmitters and receivers, the receiver closest to the transmitter is the receiver that receives the most signal. As the object moves away from the array of transmitters and receivers, the signal on the farthest receivers will increase. Indeed, the object is in this case in the axis of the latter. At the same time, the signal on the nearest receivers decreases. Indeed, the object is less and less in the axis of these receivers.

By using an interpolation method, for example the average of the signal on the receivers weighted by the respective position of each receiver, a value proportional to the distance of the detected object is obtained. This is true regardless of the reflectivity or the size of the object.

By coupling this device to a device for amplifying the signal and compensating for ambient light as described in document FR 08 59048, it is possible to produce a detector that can operate under direct sunlight. The device for determining the position of an object, however, has the disadvantage of having to implement a large number of components. To increase the detection distance, it is indeed necessary to multiply the receivers. This disadvantage affects the final cost of the product but also its speed of reaction. Indeed, the use of more receivers implies more acquisitions and the total acquisition time is thereby lengthened.

Moreover, this device has the disadvantage of having to find a compromise between the opening of the receivers and the linearity of the output signal. Indeed, since the receivers have a narrow aperture angle, the curve representing the weighted average of the signals as a function of the distance has a significant slope but will be very little linear and in the form of steps.

On the contrary, if receivers with wide aperture angle are used, the curve representing the weighted average of the signals will be relatively linear but the signal will be less important and the slope will be weak. This increases the uncertainty of positioning.

Finally, these devices show a sensitivity to variations in the angular characteristics of the receptors. This is a significant disadvantage because, for many types of receivers, the manufacturing processes are such that the angular sensitivity can vary greatly from one receiver to another. This causes significant variations in characteristics for the position sensing device. It should also be noted here that the receivers used in devices of the type of those described in document FR 2 899 326 do not have the possibility of determining an angular direction in which the object is located. This is due to their angular sensitivity characteristics which is not at all constant and regulated by a general law of optics.

More generally, the position detection devices of the type of the document FR 2 899 326 make it possible to know only the distance to which an object in front of an emitter in the emission beam of this latter is located. It is thus necessary to know the emitter having illuminated the object to completely determine the position in which the object is located. An overall illumination of the surface does not allow access to the determination of position.

The disadvantages described above, and in particular the non-linearity, are the main factors limiting the performance of this type of position determination device.

Finally, we know that there are "Touch Pad Capacitive" systems and "touch screen tiles" to determine the position of a finger on a surface.

There are numerous documents describing these systems which all implement contact detection techniques very distinct from contactless technologies such as those described above and which relate to the field of the invention. Contact technologies, however, are the benchmark for detecting two-dimensional positions. Object and summary of the invention

The main object of the present invention is therefore to overcome the drawbacks of the operating principles of position detection devices of an object on a surface of the prior art by proposing an optical and electronic system for determining a position of a object present on a predefined surface, the system comprising at least one emitter disposed on a so-called emission side of the predefined surface emitting a beam of electromagnetic radiation of wavelength between 100 nm and 10 μιτι, covering the surface predefined and having specific spectral and / or modulation characteristics making it possible to detect it, even in the presence of high intensity natural light,

this system comprising two devices for detecting an angular direction in which there is the object each having a coverage area, these two devices being positioned on either side of the emission side such that the coverage areas each include the predefined surface, these two detection devices being able to determine the angular direction of the object receiving signals having the spectral and / or specific modulation characteristics reflected by the latter, and comprising a module for determining the position of the object for, knowing the position of the two devices with respect to the predefined surface and the angular direction in which the object is located with respect to each of the detection devices of an angular direction, to deduce the position of the object on the predefined surface by intersection of the predefined surface and the two defined angular directions p ar compared to the detection devices.

The invention makes it possible to score or write in a manner comparable to what is achieved with a capacitive or resistive touch pad. This is achieved according to the invention with a very inexpensive optical and electronic method and having the advantage of being usable under high ambient light, including under direct sunlight by means of an ambient light compensation device. The angular detection being done on reception of the signals having particular optical characteristics, the invention ensures that the detection of the object is effective even under intense lighting. In addition, it should be noted that the size of the system according to the invention is low since only one transmitter and two devices for detecting an angular direction are required. The system according to the invention implements two devices for detecting an angular direction.

Devices for detecting a different angular direction can be used. By associating a second device for detecting an angular direction of the same type, it is thus possible, by ensuring that the coverage areas of these two detection devices cover the predefined surface in which the object can be, to obtain the position of an object on this surface. The invention is capable of using any type of device for detecting a known angular direction when two of these devices are placed on either side of at least one transmitter capable of illuminating the whole of the predefined area. Such a single transmitter must be provided with a specific lens, allowing it to illuminate at a very wide illumination angle. Such a lens degrades the performance of the transmitter by decreasing the signal and increasing the divergence.

More specifically, the invention uses detection devices using light, or any other electromagnetic radiation with close physical properties, especially infrared or ultraviolet radiation; that is to say any electromagnetic radiation whose wavelength is between 10 pm and 100 nm.

It is common to use such radiation and exploit the reflection of it on the object to be detected. Any visible electromagnetic radiation is therefore concerned with the terms "light" and "optics" used hereafter, but also invisible electromagnetic radiation with wavelengths and near physical properties, namely infrared and ultraviolet radiation.

According to a preferred characteristic of the invention, the beam of an electromagnetic radiation having a wavelength of between 100 nm and 10 μm, covering the predefined surface and having specific spectral and / or modulation characteristics, is a beam of one infrared radiation.

Indeed, it is sometimes desirable to use, for detection, visible radiation for the user, for aesthetic reasons or for provide a visual feedback. However, in most cases, however, one will wish to make the detection device invisible to the user. For this purpose, the use of invisible radiation, infrared or ultraviolet, will be preferred.

According to an advantageous characteristic of the invention, the system comprises a plurality of transmitters arranged on the transmitting side for illuminating the predefined surface, each of the emitters emitting a collimated beam along a line, the set of beams covering the entire predefined area.

This feature makes it possible to use simple transmitters without any particular optics than that which makes it possible to collimate their beams, which is a classic characteristic in commercial transmitters. In addition, the use of multiple transmitters ensures a more uniform illumination of the entire predefined area.

According to an advantageous characteristic, permitted by the preceding characteristic, the system comprises a control module for the ignition of the emitters able to control successive ignitions of the emitters.

Each emitter illumination defining a predefined line of the predefined surface, this characteristic makes it possible to couple the use of the detection devices of an angular direction with the knowledge of the lighting sequence of the emitters. It then becomes possible to check the coherence of the detections of the angular directions made by the detection devices at a given moment since the determined intersection must then be on the line defined by the light beam of the emitter on at the given moment. .

According to a preferred characteristic, the emitter control module is able to produce, in real time, the emitter illumination sequences as a function of the determined position of the object on the predefined surface.

Indeed, it can be advantageous, once the position of the object determined, to turn on only transmitters neighboring this position to allow a very fast tracking of the position of the object on the predefined surface. Such intelligent management of the emitters' lighting allows a very large speed of reaction of the system for determining the position of an object present on a predefined surface according to the invention.

In a preferred embodiment, the devices for detecting an angular direction in which an object is located each comprise at least two receivers each having a reception surface on which the radiant power received from an object is dependent on the object. angle at which the object is viewed according to a strictly monotonic dependence curve of the radiant power received as a function of the angle at which the object is viewed, the two receiving surfaces being placed side by side but each in a plane distinct, the two planes forming between them an angle between 1 ° and 150 ° and thus forming a so-called edge edge of the device, the device being intended to be positioned in such a way that the portion of the space defined between these two plans includes the predefined surface on which the object may be located,

each device further comprising an electronic module comprising means for, upon illumination of the predetermined surface with radiation having specific spectral and / or modulation characteristics:

receiving the optical signals received by each of the receivers; extracting, from each signal received by a receiver, the radiant power from the optical signal having specific spectral and / or modulation characteristics received by this receiver,

- from these radiant powers, determine the angles under which the object is seen by each of the receivers, considering that the receivers receive the same luminous intensity but at different angles,

- determine the angular direction of a plane passing through the edge of the device and where is the object.

With this characteristic, each device for detecting an angular direction comprises two receivers positioned in two distinct angular positions, these two receivers having a surface for which the angle under which the object is viewed monotonically influences the radiant power received on the receiver. Considering that the luminous intensity received on the two receivers of each device for detecting an angular direction is identical, the only difference between the intensities received on the two receivers of the same detection device is thus due to the angle under which is seen the object. This is true when the distance between the two receivers is negligible compared to the receiver-finger distance. This is the hypothesis on which the invention is based.

It is thus possible directly to obtain this angle. Each of the angular direction detecting devices is then used to determine an angle on either side of the transmitting side. The intersection of the two planes passing through the edges of the detection devices and oriented in the detected angular directions defines a straight line. The intersection between this line and the predefined surface gives the position of the object.

According to an advantageous characteristic, each receiver comprises a reflector bringing the light received on the reception surface of the receiver on a Lambertian detection surface, this Lambertian detection surface then being placed in a same plane parallel to the transmission plane of the transmitter. .

With this feature, it is allowed that the only feature of relief above the predefined surface is the reflector. Indeed, with this embodiment, the two lambertian detection surfaces are positioned on the same plane which is advantageously identical or at least parallel to that of the predefined surface, which is quite interesting from the point of view of the integration of the system. Typically, such a Lambertian detection surface will be that of a photodiode or phototransistor component without a lens, which is commercially available. Indeed, the angular sensitivity of this kind of component without a lens is fixed by the laws of physics and optics. It is therefore proportional to the cosine of the angle formed by the light source, here the object reflecting the light and the normal to the sensor.

In a preferred embodiment, the reflector has a surface corresponding to one-half of the solid formed by the revolution of the base of a parabola about an axis perpendicular to the focal axis of the parabola, the halves being determined from the another of a plane passing through the focal axis of the parabola, the focus of the dish located in the median plane of the reflector being located on the sensing surface. Such a reflector is particularly adapted to retain the dependence property of the radiant power received at the angle under which the object is seen. Such a reflector thus makes it possible to relate the angular sensitivity according to Lambert's law of the detection surface to the reception surface which is perpendicular to it and which is the entrance surface of the reflector.

Advantageously, the detection surface is centered on the focus of the dish.

This characteristic makes it possible to maintain a good compactness of the receiver and also to ensure a dependence of the radiant power at the reception angle.

According to an advantageous characteristic, the axis of revolution of the reflector is such that the focus of the dish is inside the reflector.

This characteristic makes it possible to place the sensing surface centered or slightly offset on the focus of the dish.

Advantageously, the focal length of the dish is between

0.5 and 1.2 times the size of the photosensitive surface of the detector.

This characteristic makes it possible to optimize the ratio between incoming energy and size of the device.

The invention also relates to an optical and electronic method for determining a position of an object present on a predefined surface, the method comprising the steps of:

- Have at least one transmitter on a so-called emission side of the predefined surface emitting a beam of electromagnetic radiation of wavelength between 100 nm and 10 μιτι covering the predefined surface and having spectral characteristics and / or specific modulation to detect it, including in the presence of high intensity natural light,

disposing, on both sides of the emission side, two devices for detecting an angular direction in which the object, each having a coverage area, is located, so that the coverage areas each include the surface predefined,

detecting two angular directions in which the object is located with each of the angular direction devices, determining the position of the object on the predefined surface, knowing the position of the two devices with respect to the predefined surface and the angular directions in which the object is located with respect to each of the detection devices of an angular direction, by intersection of the predefined surface and the two angular directions determined with respect to the detection devices.

Brief description of the drawings

Other features and advantages of the present invention will emerge from the description given below, with reference to the accompanying drawings which illustrate an embodiment having no limiting character. In the figures:

- Figure 1 shows the basic principle of the invention;

FIG. 2 schematically shows an embodiment according to the invention;

FIG. 3 schematically shows a device for detecting the angular direction according to a preferred embodiment of the invention;

FIG. 4 shows a preferred example of a device for detecting an angular direction according to the invention;

- Figure 5 illustrates Lambert's law;

FIG. 6 shows a section of a reflector used in the detection device shown in FIG. 4.

Detailed description of an embodiment

FIG. 1 shows the basic principle of the invention for determining the position of an object 2 on a predefined surface S of width L and depth P.

According to the invention, at least one emitter E is disposed on an emission side denoted CE of the surface S. This emitter E emits a beam of radiation covering the predefined surface S and has spectral and / or specific modulation characteristics enabling to detect it, even in the presence of natural light of high intensity. Typically, a compensation principle as described in document FR 08 59048 is used. The system according to the invention comprises two detection devices D1 and D2 of an angular direction, each able to determine an angular direction al, a2 in which the object 2 is located with respect to the device concerned. Each of the angular direction detecting devices has a coverage area covering the entire S surface.

It is therefore necessary that the two devices D1 and D2 each cover at least one quarter of space in which the surface S is viewed from each of the detection devices.

The finger 2 reflects a portion of the light emitted by the emitter E to the detection devices of an angular direction D1 and D2. This reflected light is processed by each detection device and the angular direction is thus detected. The two devices D1 and D2 are connected to an electronic module 10 which is able to calculate the position XY of the object 2 on the surface S, as a function of the position of the detection devices D1 and D2 with respect to the predefined surface S and according to the angular directions a1, a2 in which the object 2 defined by each of the angular direction detection devices D1 and D2 is located.

Indeed, according to the two angles determined by these devices, by triangulation, the module 10 determines the position of the object using the formula: sin (2) cos (al)

A - L ·

sin (or1) cos (or2) + cos (or1) sin (or2)

sin (orl) sin (or2)

sin (or1) cos (or2) + cos (or1) sin (or2)

Figure 2 shows schematically an advantageous embodiment of the invention.

In this embodiment, a plurality of emitters E1 to E7 are disposed on the emission side CE of a surface S. The emitters E1 to E7 are aligned next to one another and may each have a lens Ll to L7 for collimating the emitted light in a substantially parallel beam. FIG. 2 shows two beams F2, F3 emitted by the emitters E2 and E3. We see that these beams are slightly divergent and illuminate the entirety of the predefined surface without hole or dead zone between them on the surface S. The fact of collimating the beams also makes it possible to increase the range of detection and to allow that the detection remains in the predefined area. It should be noted here that, advantageously, the light will be collimated on the predefined surface in order to avoid parasitic three-dimensional detections.

They advantageously emit infrared light with particular spectral and modulation characteristics making it possible to detect the infrared radiation emitted by the emitters, even in the presence of invading natural light. Typically the light is then modulated with a modulation frequency between 30 and 100 kHz. Below 30 kHz, the device will be more disturbed by the lights powered by an electronic switching system, more than 100 kHz, sensitivity to radio frequency signals becomes troublesome. The spectral sensitivity of the receiver is also chosen as thin as possible, centered on the spectral emissivity peak of the transmitter.

The plurality of transmitters may be replaced by a single transmitter, provided with a lens transforming its output beam into a plane beam covering the entire predefined area S. It is also possible to use a light plan generator based on on a laser technology.

On each side of the row of emitters E1 to E7 are placed two devices for detecting an angular direction D1 and D2. These devices for detecting an angular direction D1 and D2 are capable of receiving and processing a radiation, preferably an infrared radiation, having particular modulation characteristics for determining the angular direction of the object 2, under which this object 2 of the device is seen. detecting an angular direction D1 and D2.

Thus, upon receiving a light having the specific modulation characteristics expected for illumination by one of the emitters and reflection on an object 2 present on the surface S, the detectors D1 and D2 each determine an angular direction al and a2 in which find the object 2. Here, the angular directions are angle values α1, α2 between the emission side CE and the plane PI or P2 passing through the object 2 and the device D1 or D2.

Once each of the two devices has determined this angular direction, it is sent to a module which determines the position of the object 2 on the surface S according to the principle described in FIG.

FIG. 3 shows a particular embodiment of the angular direction detection device D2 used in FIG. 2. In this preferred embodiment, the detector D2 comprises two receivers R1 and R2 each comprising a reception surface S1 and S2. On these surfaces S1 and S2, the radiant power received from the object 2 is dependent on the angles a and β under which the object 2 is seen with respect to the normal to these surfaces S1 and S2. This dependence of the radiant power received as a function of the angle at which the object 2 is viewed follows a strictly monotonous dependence curve.

According to this embodiment, the two receiving surfaces S1 and S2 are placed side by side but each in a separate plane. The two planes make, between them, an angle equal to 90 ° in the example shown in FIG. 3. The intersection between the two planes forms an edge called "edge of the device" denoted AD2. We see here that the portion of the space defined between the two planes includes the predefined surface S on which object 2 may be found.

The device D2 includes or is connected to an electronic module M2 which receives the signals received by each of the two receivers R1 and R2. This module M2 is able to extract, from each signal received by a receiver R1 or R2, a radiant power having spectral characteristics and / or specific modulations received by this receiver.

Assuming that the receiving surfaces have Lambertian behaviors (Lambert's law) that is to say that the radiant power received on a surface is proportional to the cosine of the angle under which the reflective object is seen relative to the normal at this surface, the received radiant powers are expressed then in the form:

5 ₂ = S _2/0 .cos () From these radiant powers, the electronic module M2 considers that the distance between the two receivers is negligible compared to the distances between the transmitter and the object and between the detector and the object.

He considers that the two receivers RI and R2 are merged. Thus the two receivers R1 and R2 receive the same luminous intensity but at different angles and therefore that Si, ₀ = S ₂ , o = S ₀ . Since the two receivers are also placed at 90 ° to one another, β = π / 2 - α.

So :

5 ₂ = S ₀ .cos (7t / 2 - a) = So.sin (a)

So = a

The value of the reflected signal is then eliminated and the angle a is thus obtained as a function of the two received signals. The module M2 then determines the angular direction β under which the object 2 is seen by the receiver R1, then directly the angular direction oc2 of a plane P2 passing through the edge AD2 of the device.

However, it is clearly seen in FIG. 3 that it is not possible to distinguish the difference in position between the two objects 2 _X and 2 ₂ that are in the same angular direction with respect to the device for detecting a direction. angular D2. The measurement made on the other side of the EC emission side by the detector D1 makes it possible to completely determine the position of the object 2 by determining the angular direction α1 of the plane Pl.

It can be seen here that the object can exhibit any reflection characteristic of the light emitted except in extreme cases for which the approximations made above are no longer valid, especially when the specular component of the reflecting object is predominant. This is the case for mirrors, polished metal objects. This is not detrimental to the determination of the two-dimensional position of the object as soon as two angular measurements are taken on each side of the emission side CE.

It is noted here that lambertian receptors are sensitive in space. It can therefore occur three-dimensional parasitic detections. In this case, an optic is added to restrict the sensitivity of the receivers to the plane. This further increases their sensitivity in this plane. Such optics only act on the sensitivity in the direction perpendicular to the predefined surface S.

It is possible to have the light-sensitive components without optical in the corner trade as shown in Figure 3. Nevertheless, these, which are generally found in a package devoid of optics, are welded into general parallel to the printed circuit. The low-cost realization of the detection device of an angular direction as shown in Figure 3 with discrete components is difficult.

Figure 4 shows a preferred embodiment of the RI and R2 receptors. In this preferred embodiment, the receiving surfaces S1 and S2 are input surfaces in a reflector RF1, RF2. Each of these input surfaces S1 and S2 belongs to a plane. The intersection of the two planes carrying the two receiving surfaces S1 and S2 defines the edge AD2 of the device D2.

The reflectors RF1 and RF2 reflect the radiation passing through the receiving surfaces S1 and S2 respectively to a detection surface SD1 and SD2. These detection surfaces SD1 and SD2 are coplanar.

For the implementation of the invention, it is essential that the radiant power which strikes the detection surface SD1 or SD2 is in strictly monotonic dependence with the angle under which the object is seen with respect to the edge AD1 or AD2.

In the preferred embodiment shown in FIG. 4, the reflector RF1 has particular properties making it possible to reflect all the rays striking the reception surface S1 in order to bring them back to a Lambertian SD1 detection surface while maintaining the strictly monotonic variation of this last between received power and viewing angle.

This characteristic makes it possible, assuming that the two receivers R1 and R2 receive the same light intensity, to determine the angular direction of the plane passing through the edge AD2 in which the object is located as described previously.

The reflector RF1 also plays the role of optical selection in space. Indeed, the properties of the reflector RF1 make it possible to receive as radiation from the proximity of the predefined surface. This prevents parasitic detections in three dimensions.

Lambertian surfaces are typically commercial components without a lens. Figure 5 illustrates the Lambertian property of a component. When the object 2 is seen with respect to the normal to the detection surface SD with an angle a, the surface SD emits an electrical signal proportional to the radiant power which it receives which, at fixed luminous intensity, is proportional to the cosine from the angle a.

FIG. 6 shows a median section of a reflector as used in FIG. 4. This section forms a parabola arc of focus F and focal axis OX. The reflector is the solid obtained by revolution of this arc on a half-space around the axis OZ perpendicular to the focal axis OX. This reflector makes it possible to maintain the dependence at the angle under which the object is viewed and makes it possible to ensure good planar sensitivity to the detection devices of an angular position. Such a reflector also makes it possible to obtain a coverage area of a quarter of usable space for the production of a system according to the invention.

Finally, we note that various implementations can be made according to the principles of the invention.

Claims

1. An optical and electronic system for determining a position of an object (2) present on a predefined surface (S), the system comprising at least one transmitter (E) disposed on a so-called emission side (CE) of the predefined surface (S) emitting a beam (F) of electromagnetic radiation of wavelength between 100 nm and 10 μιτι covering the predefined surface (S) and having specific spectral and / or modulation characteristics allowing the detect even in the presence of natural light of high intensity,

this system comprising two detection devices (D1, D2) of an angular direction (ocl, oc2) in which there is the object (2) each having a coverage area, these two devices (D1, D2) being positioned from both sides of the emission side (CE) in such a way that the coverage areas each include the predefined surface (S), these two detection devices (D1, D2) being able to determine the angular direction (ocl, oc2) of the object (2) receiving signals having the specific spectral and / or modulation characteristics reflected therefrom, and comprising a module (10) for determining the position of the object (2) for, knowing the position of the two devices (D1, D2) with respect to the predefined surface (S) and the angular direction (ocl, oc2) in which the object (2) is located with respect to each of the detection devices (D1, D2) of an angular direction (ocl, oc2), deduce the position of the object (2) on the area (S) predefined by intersection of the predefined area (S) and the two angular directions (oc1, oc2) determined with respect to the detection devices (D1, D2), the system being further such that the detection devices ( D1, D2) of an angular direction (ocl, oc2) in which there is an object (2) each comprise at least two receivers (R1, R2) sensitive to electromagnetic radiation with a wavelength of between 100 nm and 10 nm. μιτι, delivering a raw photo-current output and each having a receiving surface (S1, S2) on which the radiant power received from an object (2), and therefore the raw photo-current output, is dependent on the angle (α, β) under which the object (2) is viewed according to a strictly monotonic dependence curve of the radiant power received as a function of the angle (α, β) under which the object (2) is seen, the two receiving surfaces (S1, S2) being placed side by side but each in a separate plane, the two planes forming an angle between them between 1 ° and 150 ° and thus forming a so-called edge edge of the device (AD), each device (D1, D2) being intended to be positioned in such a way that the portion of the space defined between these two planes includes the surface ( S) predefined on which the object (2) can be found,

each device (D1, D2) further comprising an electronic module (M) comprising means for, upon illumination of the predefined surface (S) with radiation having specific spectral and / or modulation characteristics:

receive the signals received by each of the receivers (R1, R2),

extracting, from each signal received by a receiver (R1, R2), the radiant power from the optical signal having specific spectral and / or modulation characteristics received by this receiver (R1, R2),

- from these radiant powers, determine the angles (α, β) under which the object (2) is seen by each of the receivers (RI, R2) while considering that the receivers (R1, R2) receive the same luminous intensity but under different angles (α, β),

- Determine the angular direction (ocl, oc2) of a plane (P1, P2) passing through the edge of the device (AD1, AD2) and where the object (2).

2. System according to claim 1, characterized in that it comprises a plurality of transmitters (E1 to E7) arranged on the transmit side (CE) to illuminate the predefined surface (S), each of these transmitters (Ei ) emitting a beam (Fi) collimated along a line, the set of beams (Fi) covering the entire surface (S) predefined.

3. System according to claim 2, characterized in that it comprises a control module of the ignition of the emitters (Ei) adapted to control successive ignitions emitters (Ei).

4. System according to claim 3, characterized in that the control module of the ignition of the emitters (Ei) is adapted to develop, in real time, illumination sequences emitters (Ei) according to the determined position of the object (2) on the predefined surface (S).

5. System according to one of the preceding claims, characterized in that each receiver (R1, R2) comprises a reflector (RF1, RF2) returning the light received on the receiving surface (S1, S2) of the receiver (R1, R2 ) on a lambertian detection surface (SD1, SD2), the two lambertian detection surfaces (SD1, SD2) then being placed in a same plane parallel to the emission plane of the emitter (E).

6. System according to claim 5, characterized in that the reflector (RF1, RF2) has a surface corresponding to one half of the solid formed by the revolution of the base of a parabola around an axis perpendicular to the focal axis of the parabola, the halves being determined on either side of a plane passing through the focal axis of the parabola, the focus (F) of the parabola situated in the median plane of the reflector (RF1, RF2) being located on the detection surface (SD).

7. System according to claim 6, characterized in that the detection surface (SD) is centered on the focus (F) of the dish.

8. System according to claim 6, characterized in that the axis of revolution of the reflector (RF1, RF2) is such that the focus (F) of the dish is inside the reflector (RF1, RF2).

9. An optical and electronic method for determining a position of an object (2) present on a predefined surface (S), the method comprising the steps of:

- Have at least one transmitter (E) on a so-called emission side (CE) of the predefined surface (S) emitting a beam (F) of radiation covering the predefined surface (S) and having spectral characteristics and / or specific modulation to detect it, including in the presence of high intensity natural light,

- have, on both sides of the emission side (CE), two detection devices (D1, D2) of an angular direction (ocl, oc2) in which is the object (2) each having a coverage area, such that the coverage areas each include the predefined surface (2), the detection devices (D1, D2) of an angular direction (ocl, oc2) in which there is an object (2) comprising each at least two receivers (R1, R2) sensitive to electromagnetic radiation with a wavelength between 100 nm and 10 μιτι, delivering a raw photo-current at the output and each having a reception surface (S1, S2) on which the radiant power received from an object (2), and therefore the raw photo-current delivered at the output, is dependent on the angle (α, β) under which the object (2) is viewed according to a curve of strictly monotonic dependence of the radiant power received as a function of the angle (α, β) under which is seen the ob jet (2), the two receiving surfaces (S1, S2) being placed side by side but each in a separate plane, the two planes forming between them an angle of between 1 ° and 150 ° and thus forming a so-called edge of the device (AD), each device (D1, D2) being intended to be positioned in such a way that the portion of the space defined between these two planes includes the predefined surface (S) on which the object is likely to be located ( 2)

illuminate the predefined surface (S) with radiation having specific spectral and / or modulation characteristics:

receiving the signals received by each of the receivers (R1, R2) extracting, from each signal received by a receiver (R1, R2), the radiant power from the optical signal having specific spectral and / or modulation characteristics received by this receiver (R1, R2),

- from these radiant powers, determine the angles (α, β) under which the object (2) is seen by each of the receivers (RI, R2) while considering that the receivers (R1, R2) receive the same luminous intensity but under different angles (α, β), determining, for each detection device, the angular direction (oc1, oc2) of a plane (P1, P2) passing through the edge of the device (AD1, AD2) and where the object (2) is located,

thus detecting two angular directions (ocl, oc2) in which the object (2) is located with each of the angular direction detection devices

(D1, D2),

determining the position of the object (2) on the predefined surface (S), knowing the position of the two devices (D1, D2) with respect to the predefined surface (S) and the angular directions (ocl, oc2) in which is the object (2) relative to each of the detection devices (D1, D2) of an angular direction, by intersection of the predefined surface (S) and the two angular directions (ocl, oc2) determined with respect to detection devices (D1, D2).