CH656731A5 - APPARATUS FOR OPTICAL LOCATION OF POSITION. - Google Patents

Description

The invention relates to an optical position location apparatus for locating the position of an object along one or more coordinate axes and for determining other measurable parameters of the object.

In the prior art, there are several devices designed to locate optically, or by a combination of mechanical and optical elements, an object in a one or two-dimensional reference system. Unfortunately, more recent tests in the field of electro-optical "rangefinders" and / or "locators" have often posed problems considerably limiting their effectiveness and their large-scale use. Two of these devices are described in US Patent No. 3,184,847 and in the article "Let Your Fingers to the Talking", Volume III, No. 8, BYTE Magazine, August 1978, this article on a touchless touch analyzer.

One of the undesirable features of all of the prior art is the high costs due to the particularly large number of components required to assemble the devices into a delicate operating apparatus. The fact that we rely on practically dozens of light sources and equivalent numbers of “tuned” photosensitive diodes significantly limits the efficiency and resolution of prior optical analyzers while simultaneously requiring significant expenditure in the form of electronic components. expensive, which makes the uses and applications of the devices impractical.

Other previous tests required the attachment of grids, photocells or other special accessories to the object to be located.

Likewise, the design of most prior devices often poses difficulties with regard to compatibility with display devices capable of otherwise presenting the results of the analysis or exploration operation. In addition, when such display devices are used, they themselves require reinterpretation due to the invariable "non-linear" output signal of these devices.

Certain prior devices require retroreflectors and therefore reveal great difficulties in locating reflective objects.

All prior devices too often rely on less advanced optical techniques, as is the case of the device described in the aforementioned patent No. 3,184,847 in which parabolic mirrors, by the very nature of their nature, impose parameters d '' large dimensions. In addition, there is a great difficulty in extending the possibilities of the devices of the prior art beyond one or two dimensions and few devices, if any, are capable of effectively solving the localization and other parameters of an object in a three-dimensional "corridor" or along at least three coordinate axes arranged in two dimensions. In addition, the prior devices suffer from limited spatial resolution and low exploration speeds, and therefore from limited temporal resolution.

The object of the invention is therefore to provide a relatively inexpensive optical position locating device, requiring a minimum of components, which is relatively compact and light and which can therefore be easily mass produced. The localization device must have great possibilities of spatial resolution and temporal resolution and it must be designed to describe quickly and with precision parameters of an object located in its zone or “window” of localization. The device must make it possible to describe the position and other parameters of objects which are not normally processed, such as fingers, pens or pencils. The optical position location device must be compatible with various display visuals and it must be capable of describing location information suitable for any analysis carried out by a user, or else having to be introduced into other systems, a desirable way to avoid complex conversions, for example in a linear form in order to avoid trigonometric conversion programs.

In an inexpensive variant, a precise and efficient localization device must be suitable for a very large number of applications ranging from computer input of information (instead of photostyles and keyboards) to toys, automatic controls of industrial equipment and for all other uses such as the choice of menus, where an accelerated automatic determination of parameters of an object such as position, size and even speed, is necessary.

In the same way, it must be able to be adapted to an analysis of a three-dimensional "corridor" as well as the position and other parameters of an object located in this three-dimensional space, by several different embodiments, including the superposition of several two-dimensional units and / or the use of the intensity level analysis of radiant energy in a single two-dimensional unit, capable of describing a third dimension of an object in its localization area or window.

He must be able to use distributors, collectors and three-dimensional selective aiming explorers.

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Another object of the invention is to request a minimum number of sources of radiant energy or light emissions and of photodetection elements, by using a single source of radiant energy associated with a rotary explorer. improved selective sighting and a detector which, in combination with an improved electronic circuit and a minimum of electronic components, accurately and quickly describes the parametric information indicated above.

The invention also aims to convert complex movements, such as those of human fingers in action, into time-varying signals in order to allow a person to transmit large amounts of complex information to machines or to other devices. 'other people. Another object of the invention is to replace the switches.

Another object of the invention is an improved rotary explorer or analyzer which, by its nature, is balanced so as to be able to operate at high speed, and which allows the use of a fixed detector in order to avoid having to use slip ring connectors. Another object of the invention is to perform an optical scan along a linear axis by means of a simple rotary explorer or analyzer, producing a non-sinusoidal linear scan in which increments of linear displacement, of equal dimensions, the along the linear axis corresponding to increments of angular displacement, of equal dimensions, of the explorer.

The invention therefore relates to an optical position location device intended to locate the position of one or more objects in a location area or "window", along one or more coordinate axes arranged in one or more dimensions, and also intended determining other measurable parameters of this or these localized objects such as their dimensions; this apparatus is defined by claim 1 and the objects mentioned above.

The device comprises a device for emitting radiant energy, as well as several distributors which cooperate with the emitter of radiant energy and which distribute the radiant energy emitted on the location area, from a position located at side of part of this area. One or more integrated collectors, which correspond respectively to the distributor or distributors, are arranged along a second part of the location zone, substantially opposite to the first part, so as to cooperate with the corresponding distributor or distributors. The integrated collectors receive and transfer the radiant energy which manages to pass through the localization zone, as well as indications of modification or alteration of this energy, to the detection device, preferably located in a single position towards which the radiant energy transferred. The apparatus further comprises a device for selectively targeting parts, related to position coordinates, of the radiant energy distributed by the distributors, in order to detect and describe properties of the radiant energy which have been modified by following the presence of the object at these position coordinates in the location area to determine, consequently, the position of the object in the location area, as well as other parameters of the object.

The distributing devices, the collecting devices and the selective aiming device together ensure that, at a given moment, practically all of the radiation reaching the detector, in the absence of an object in the location area, crosses this location area on a range corresponding to a single position coordinate, this range being at least as small as the smallest object to be located.

Consequently, the apparatus distributes radiant energy from a source in an area, in an orderly fashion, collects and transfers or transmits this energy, having passed through the area, to a detector, and selectively targets certain parts, related to coordinates. of position, of this radiant energy, all these operations being intended

In a preferred embodiment of the invention, the radiant energy emitted by the emission device comprises non-polarized electromagnetic light and the emission device comprises an incandescent lamp.

In a preferred embodiment, the device for emitting radiant energy is associated with a rotary projection element 5 which transmits a light beam successively along the distributor of each respective axis. The distributors cause the beams to pass adjacent narrow, and preferably parallel, segments of the location zone, first along one axis, then along the other axis, repeatedly. These exploration beams are received by the collectors who direct them towards a detector. The detection device preferably comprises a single photosensitive element on which all the beams are finally made to converge, or alternatively, a small number of individual detectors grouped near the point of convergence. The detection cell cooperates with a signal processing device which detects whether the scanning beam is interrupted at any given time, and to what extent it is interrupted, information from which the position and dimension of an object located within a location range can be determined. The beam emitting device can advantageously comprise a laser, or else a suitable column optic associated with a light source.

In another embodiment of the invention, the radiant energy source comprises several individual light sources such as light emitting diodes or infrared diodes, spaced along the first part of the location area for also form, at the same time, the distribution device. In this particular embodiment, each of the light sources preferably comprises a light-emitting diode placed behind a series of deflectors and / or other optical elements which produce a group of substantially parallel beams passing through the localization zone. Collector devices are aligned respectively on them. Furthermore, in this embodiment, the detection device can comprise one or two photosensitive elements which cooperate with the collecting device so as to receive the transmitted energy. An exploration of the aiming surface to selectively target certain parts of the area can be carried out by pulse control of each of the light-emitting diodes, in sequence. As a variant, the explorer-detector described below can be used, whether the light-emitting diodes 40 are lit continuously or lit in synchronism with the explorer-detector.

In a preferred embodiment of the invention, the device for emitting radiant energy comprises a continuous and substantially stationary light source and it comprises several screens which intercept and absorb rays directed towards positions other than those located along the respective distributors. In this particular embodiment, the detection device is associated with a selective aiming device which comprises a rotary explorer or analyzer intended to selectively analyze certain parts of the continuous radiant energy distributed simultaneously over the extent of the location area. . The analyzer and the detector receive the radiant energy either directly or in a modified form and, in response to this energy, they produce an electrical signal proportional to the quantity of radiant energy measured, the radiant energy being modified to a degree just measurable by any object blocking the radiant energy distributed over the extent of the location area.

In this preferred embodiment, the associated analyzer and detector further comprise screens absorbing radiant energy 60 which is not transmitted from the respective integrated collector to the detector. The analyzer and the detector themselves comprise a motor connected to an optical element so as to rotate it. A slit mask is attached to the optical element with which it rotates, this mask having a slit sized to describe the “part” 65 of radiant energy transmitted and detected at a given instant in the rotation of the analyzer-detector assembly. . This set preferably includes a single photodetector element placed functionally in alignment with the element and the slit mask.

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Radiant energy is thus transmitted from the respective integrated collector, passes through the optical element, is reflected and focused through the slit mask, and arrives on the surface of the photodetection element. The rotating optical element and the mask allow the analyzer assembly to explore or analyze, position by position, passing through a coordinate axis of the location range and, consequently, through the remaining coordinate axes from the location range. By rotating the optical element and making it perform the exploration function, the photodetector itself can be made immobile by mounting it substantially on the axis of the optical element. The refractive and reflecting properties of the optical element then project the light received from the particular radiation position, which is instantly aligned with the optical element, axially on the fixed detector. The latter is preferably a phototransistor, although any photoelectric transducer can be used.

The rotating optical element may include an optical refraction sphere containing a diagonal section plane. A reflection can result from different refractive indices of the material of the sphere (preferably acrylic), and of its surface which can be silver. The slit mask is mounted in axial optical alignment between the optical sphere and the detector element.

More generally, the optical element may be a biradial ellipsoid, having a horizontal radius and a slit width which together establish the viewing width, as well as a vertical radius and a slit height which together establish the height of sight.

Blocking elements can be used with the radiant energy emitting device in the embodiment described above, in order to intercept and absorb radiation directed towards positions other than those located along the distributor. . Similarly, equivalent blocking means or screens can be used with the analyzer-detector assembly, as mentioned above, for the following three purposes: preventing the analyzer from receiving accidental spurious radiation;

establishing a position reference system such that different input signals from different collectors can be separated and analyzed to determine the dimensional parameters of an object in the location range; and establish a black level reference.

The optical element can be made so as to rotate and perform scanning or exploration under the action of an electric motor. The motor can be connected by an electrical circuit to the radiating energy emission device as well as to the detector element and to an amplifier. In one embodiment, a capacitor is mounted in parallel with the motor to reduce noise from the collector. Resistors can be made to lower the control voltage and, therefore, run the motor at a desired speed. It should be noted that the temporal resolution is in inverse relation to the speed of rotation. In addition, a control circuit known in the art can be used to control and stabilize the speed of rotation of the motor.

Another embodiment of the analyzer-detector assembly uses an electronic optical analyzer or explorer with one or more photodetectors. For example, one can use a filter mask with liquid crystal bands, transmission type, comprising a large number of individual liquid crystal elements arranged close to each other in the form of "bands". When they are introduced on the path of converging light beams, we can determine the particular beams that are allowed to reach the detector by making transparent the "strip" placed on the optical path of a certain beam. Similarly, light from unwanted positions can be stopped by making the corresponding "bands" opaque. If only one or a few adjacent bands are transparent at a given time, the detector then selectively sees only the light received from the corresponding reduced part of the localization area. By making each of the successive bands transparent for a short period while the other bands are opaque, an “exploration” of the localization field is carried out.

Although such electronic shutters can be placed in any position on the light path, in a preferred embodiment, the band filter is placed near the detector so that the dimensions of the filter can be reduced due to the convergence of light beams.

Although the electronic explorer or analyzer can be used with the rotary detector described, by synchronization of the two elements, it is not necessary to use a rotating optical element. On the other hand, the position data can be derived directly according to the indication of the band made transparent and corresponding to a given output signal. Consequently, a fully electronic configuration, ideally suited for the transmission of digital output signals, is thus obtained. This avoids the mechanical elements of the rotary explorer.

Since in the embodiment of the liquid crystal strip mask explorer there is no need for the optical element to rotate, other methods for collecting the received light beams and for presenting them to the detector can be used. Although it is possible to simply allow light to converge on a detector, a preferred embodiment uses a refractive and reflecting optical element comprising a clear sphere from which a conical portion is removed to form a reflector. conical shape. The detector is then mounted above the element, on its axis, so as to receive the light which arrives at the optical element from any radial direction. Alternatively, other refractive or reflective focusing elements known in the art can be used.

An amplifier can be operatively connected to the detector element of said analyzer-detector assembly. The amplifier reacts to the detector output signal. In one embodiment in which a reverse bias photodiode is used as a detector, the amplifier proper comprises a first voltage amplifier element for converting the variable current of the photosensitive diode into a signal resulting from variable voltage. Pest suppressants can also be incorporated. A second voltage boosting element is connected by capacitive coupling to the first voltage boosting element. In one embodiment, this second voltage boosting element is further connected to a DC restorer and a Schmitt toggle in order to quantify the resulting signal into a binary digit. In the embodiment of the invention in which the signal strength is measured, the Schmitt flip-flop 45 is replaced by a buffer amplifier having a finite gain, so that the output signal is an analog signal which depends on the intensity of light arriving at the detector.

In a preferred embodiment, the analyzer-detector apparatus can be functionally connected, by means of signal processing means, to a display visual allowing a visual interpretation of the radiant energy analyzed and detected by this apparatus. For example, the waveform of the output signal can be displayed using an oscilloscope which is triggered appropriately at the same point on each of the successive scans. Waveform measurements thus displayed can be made to determine the position, size and other parameters of an interference object. Alternatively, a television monitor can be used to display an output signal depending on the existence and position of an object. It is obvious that an appropriate interface may be necessary to derive from the output signal of the localization device itself the appropriate excitation signal from the television monitor.

It should be noted that the position location device can be mounted, for example, directly on a television monitor so that an operator touching the television screen simultaneously produces a signal, at the output of the location device , corresponding to the position of the finger or the stylus. In this way, one can obtain an interactive data entry and a dis

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positive visualization that can be used with, for example, computers.

In one embodiment of the apparatus according to the invention, radiant energy filters are interposed between the distribution device and the collecting device in order to eliminate practically all the radiant energy not having the wavelengths that the filter lets through, so as to reduce both internal and external stray radiation. The filter is also used to close the enclosure and protect the components from debris and dust. In such an embodiment, the filtering device comprises a filter allowing the infrared to pass, interposed between the location area and the position location device.

The distribution device can preferably distribute radiant energy in positions situated in front of and beyond its respective part of the location range in order to describe an initial and final trajectory of radiant energy which cannot be altered or interrupted by objects, whatever their position in the location range. This therefore corresponds to reference points intended to facilitate the analysis of the radiant energy detected on this part of the range which can be interrupted by a localized object. This can also be used to avoid confusion by facilitating discrimination between an object placed at the ends of the location range and the screens associated with the analyzer-detector assembly. Finally, the uncut signal can be used as a test signal when intensity information is to be used to determine the penetration depth, to allow automatic gain control and compensation for variations in energy intensity. radiated, in opposition to the energy received,

as well as other variable parameters present.

In the preferred embodiment of the invention, the dispensing device comprises a step ladder mirror intended to receive the radiation from the device for emitting radiant energy in order to distribute it over the location area. Likewise, the preferred embodiment of the integrated collector uses an equivalent step ladder mirror intended to receive the radiant energy distributed over the location area and then transmit it to a substantially point position in which the detection device is placed. .

The distributor or collector, whichever is closest to a rotary analyzer, is designed to establish the functional relationship between the location coordinate and the angle of rotation of the analyzer. In particular, the distributor or the collector (whoever controls the functional relationship) can be designed to establish a substantially linear relationship between the position coordinate and the angle of rotation of the analyzer. The step set in steps lends itself advantageously to the establishment of various arbitrary functional relationships, because it makes it possible to locally and independently specify both the position of the mirror and the slope of the mirror (angle of reflection). For example, an advantageous embodiment uses a stepped 29 facet step assembly as a collector which establishes a linear relationship between the location coordinates and the rotating analysis angles, while keeping the light intensity substantially constant. In the 29-facet embodiment, the ridges of the facets are spaced 5.08 mm apart and the facets extend, in a curved profile, from a depth of 41.07 mm to a depth of 4.34 mm.

The design of the distributor and the collector establishes the functional relationship between the relative intensity of the radiation transmitted, in the absence of objects, and the location coordinates. In particular, it is possible to design the distributor and the collector considered as a system intended to establish a desired relationship between the relative intensity and the location coordinates. The tiered step set again lends itself to establishing such a relationship, since the various reflective facets may have different useful reflection areas. The useful reflection area is the area which extends in the desired plane and which is not masked or covered by other parts of the rung assembly and which can therefore effectively transmit the radiation to the area of location or from this area. The width of the widest shadow should be less than the width of the smallest object to locate. The tiered mirror can be tilted to virtually eliminate shadows, the facets becoming parallelograms.

In the case of larger localization areas, the individual faces of the facets of the stepped step mirrors may be focusing surfaces configured to ensure maximum radiation transmission and focusing.

In other embodiments, the manifold and manifold assemblies have reflective surfaces that do not include steps, as is the case, for example, of embodiments in which the manifold and manifold assemblies have sections parabolic, although problems of size and cost may arise.

In other embodiments, the distributor and / or manifold assemblies are refractive or consist of a combination of reflective and refractive elements. Lenses or prisms are examples of refractive assemblies, while an example of a combination of reflective and refractive elements may be constituted by a step structure in steps of transparent optical material with a coated rear surface reflecting so that the light is both refracted and reflected.

In the embodiment of the stepped mirror with 18 facets, the space requirement is reduced due to a thinner construction which compensates for the less constant light intensity as well as the need to use a trigonometric convergence program. due to the non-linear relationship between the coordinates and the analysis angle. The ridges of this 18-faceted embodiment are spaced 9.52 mm apart and extend, in a curvilinear profile, from a depth of 35.36 mm to a depth of 20.70 mm.

The invention will be described in more detail with reference to the accompanying drawings by way of non-limiting examples and in which:

fig. 1 is a top view of a preferred embodiment of the analysis apparatus according to the invention in which an assembly with 40 analyzer and detector is used with distributors and step rung collectors to locate an object in a two-dimensional location range;

fig. 2 is a schematic perspective view from above of the analyzer and detector assembly of the embodiment shown in Fig. 45. 1;

fig. 3 is a top view of the optical element of the analyzer and detector assembly;

fig. 4 is an elevation of the optical element shown in FIG. 3;

50 fig. 5 is a diagram of a circuit and components used in the analyzer of the embodiment of FIG. 1;

fig. 6 is a diagram of the amplifier circuit shown in FIG. 5;

fig. 7 is a diagram of the output display on which the location area 55 is empty or free of any obstacle;

fig. 8 is a diagram of the output display on which an object is in the location range;

fig. 9 is a diagram of the output display showing the output signal before switching on the current restorer

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fig. 10 is a diagram showing the output display after switching on the DC rectifier;

fig. 11 is a top view of an embodiment of a step ladder mirror;

65 fig. 12 is a top view of a second embodiment of a step ladder mirror;

fig. 13 is a top view of another embodiment of the optical analysis apparatus according to the invention, in which necks

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integrated readers are used with several light sources which serve simultaneously as distributors;

fig. 14 is a perspective view of an embodiment of the optical position location apparatus according to the invention used with a television monitor serving as a data entry device;

fig. 15 is a perspective view showing the use of a television monitor to display position data derived from the position location apparatus;

fig. 16 schematically shows the use of an oscilloscope to display the output signal from the optical position locator;

fig. 17 is a diagram of the synchronization signal extraction circuit of FIG. 16;

fig. 18 shows the introduction of an opaque object at various depths into the detection zone of the device;

fig. 19 is a schematic view of the display of an output signal for various penetration depths, as shown in FIG. 18;

fig. 20 is a diagram of a variant of part of the amplifier circuit of FIG. 6;

fig. 21 A, 21B and 21C are partial elevations showing the effect of an opaque object intervening in the space defined by mirrors oriented at three different angles of inclination;

fig. 22 is a partial plan view of another embodiment of the analysis apparatus using liquid crystal tape mask analysis devices with an optical detector;

fig. 23 is an elevation of a variant of the optical element shown in FIG. 22;

fig. 24 is a partial perspective view of the mask with liquid crystal band and the associated electronic circuit;

fig. 25 is a plan view of another embodiment of the analysis apparatus according to the invention comprising distributors and continuous parabolic collectors; and fig. 26 is a partial plan view of the analysis apparatus, showing the use of refractive elements.

The apparatus 20 for optical position localization, shown in FIG. 1, comprises a source 28 of radiating energy emission, in this case consisting of a fixed incandescent lamp, lit continuously and placed in a box 20a, as well as screens 27 and 29 and an assembly 48 with analyzer and detector and its screens 18 and 19. The screens 27 and 29 prevent the emission of light beams to positions other than those located along distribution devices 32 and 40.

In this particular and preferred embodiment, the distribution device 32 comprises several reflecting surfaces forming stepped steps, for example reflecting surfaces 33, 34 and 35 capable of reflecting the diverging light beams coming from the light source 28 in an array. substantially parallel light beams extending over the location zone 21. Two collectors 41 and 42 are specially designed to allow the detector-analyzer assembly 48 to rotate over a substantially equivalent radial analysis angle, to control a corresponding equivalent linear distance over the location zone 21. Consequently, when the assembly 48 with detector and analyzer rotates, an equivalent angle of rotation allows this assembly to control an equivalent part of the localization zone or "window" 21, whatever the path followed by a particular light beam. reflected so as to browse the window. This particular embodiment puts in linear form the location coordinate of the output display as a function of the radial scanning angle and, consequently, as a function of time in the apparatuses shown in FIGS. 7 to 10.

Reflective surfaces 50, 51 and 44, 45 are located, respectively, on the distributors 32 and 40 in order to distribute beams of radiant energy over areas outside the location area 21. The transmission of light from a lamp 28 towards location 44 situated at the end A of the distributor 40 is effected by transmission of a beam through the edge 24 of a filter 23 allowing the passage of red and infrared radiation, this beam then being substantially collected and received by a reflecting surface 47 and reflected towards the assembly 48 with analyzer and detector. Since no object is placed outside the window 21 in order to interfere with this beam, a signal resulting from the presence of an object at the very edge of the location zone, as shown in FIG. 8, cannot be confused with the displayed representation of the screens 18, 19. Thus, objects, even on the periphery of the location zone 21, are easily distinguished from the effect of the screens, as indicated at 124 in FIG. 8.

The embodiment described corresponds to an analysis apparatus 20 for locating and measuring parameters of an object in two dimensions, apparatus in which the two distributors 32 and 40 are placed so as to be opposite to collectors 41 and 42 respectively. Since the light source 28 is a continuous and stationary source of radiating electromagnetic energy, a network of continuous beams is produced, as indicated by beams 30 and 31 along the axis of coordinates X, and beams 14 and 15 are distributed from distributor 32 to collector 41 along the axis of coordinates Y. Consequently, the presence of an object as indicated at 52 (shown in dashed lines) blocks or otherwise modifies beam 14 radiant energy reflected from surface 33 towards surface 36. Thus, when the analyzer and detector assembly 48 rotates in order to review the part of the radiant energy that would otherwise be reflected by surface 36, the display exit age, as shown in fig. 8 shows an object 52 located at a distance Y1 from the radial time distance from the screen 18.

Although the arrangement of distributors and collectors of the embodiment of FIG. 1 is substantially orthogonal, the apparatus can use, in an equivalent manner, networks of non-orthogonal or inclined scanning beams. The filter 23 allowing the passage of red and infrared radiation is used in order to allow the passage only of wavelengths corresponding to red light and infrared through the range of location of positions, and in order to prevent all radiation non-red or non-infrared parasites entering the device. This reduces the sensitivity of the device to unwanted stray radiation, and hermetically seals the substantially toroidal enclosure to prevent entry of impurities. Other means of filtering radiant energy can be used in an equivalent manner, including a all-purpose window (transparent).

Reflective beams such as parabolic mirrors shown in 282-285 in FIG. 25, without steps, can be used. However, such configurations may require substantially deep curvilinear reflecting shapes which significantly increase the size and cost of the apparatus, problems which are resolved by the use of stepped step mirrors of particular design. In addition, refractive elements such as lenses or Fresnel-type lenses, or even refractive-reflective elements such as a reflective prism, can be used in place of distributors 32 and 40 and / or collectors 41 and 42 for transmitting the diverging light from the source 28, by refraction and / or refraction-reflection, in the form of substantially parallel beams passing through the window 21 or, as a variant, towards a detection device. Fig. 26 illustrates the use of focusing lenses 290 with the distributor 40, where the reflected beam 291 is further channeled into a collimated beam 292 by these lenses 290.

The optical analyzer 48 is shown in FIG. 2 as comprising a motor 53 whose shaft 54 is connected to an optical element 56-57 by means of a fixing member 55. An aiming reduction element 61, fixed to the optical element 56-57 in order to rotate with it, has a slot 62 which allows the transmission of "parts" of analyzed light to the detector 60 from which electrical wires 63 start.

As shown in fig. 1 and 2, the analyzer 48 rotates so as to receive radiant energy from collectors such as the collector 41. although only part of the transmitted beams

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can reach a detector 60, this part being limited by the slot 62. In the preferred embodiment, the length of the opening 62 is chosen so that the depth of the region targeted by the detector 60 is slightly greater than the thickness of the reflecting elements of the collectors 41, 42. In this way, slight axial misalignments of the analyzer 43 are tolerated without loss of the desired signal, while the foreign radiation is practically stopped.

At a constant speed of rotation, the light reflected by the collector 41 is first reviewed by the detector which rotates clockwise. Then comes a period of darkness corresponding to the presence of the screen 19 which stops the light. The analyzer then reviews the light reflected from the row of collectors 42, which is finally followed by the absence of light corresponding to the presence of the screen 18. This cycle is then repeated continuously. The screens 18 and 19 are preferably black and opaque in order to more effectively absorb unwanted rays. The photodetector 60 is held in a fixed position above the rotary mask 61.

The optical element 56-57 comprises an optically transparent sphere, preferably made of acrylic material and cut into two hemispheres. The lower hemisphere 56 is used for a balancing function in order to promote regular rotation of the optical device under the control of the motor 53 and of the shaft 54. The hemisphere 57 has a flat rear surface 57a which preferably has , an optical polish. The surface exposed towards the outside of the hemisphere 57 which, as shown in FIG. 2, receives the beams 58 of radiant energy through the element 60, behaves like a converging lens surface. The total internal refraction takes place at the surface 57b due to the nominal index of refraction of the material used (an acrylic material having an index of 1.5), while the index of the air space maintained by lugs 64 and 65 of troisement, located on the flat rear surface 57a, is 1.0.

Fig. 3 shows the optical device before the upper part 68 (fig. 4) has been removed, and figs. 3 and 4 show the embodiment of the optical device which comprises spacer pins 64 and 65 and hemispheres 56 and 57. Spherical caps 66 and 67 are opacified. Alternatively, they can be removed by cutting and the surfaces thus exposed can then be opacified.

In the preferred embodiment of the analyzer and detector assembly, a material of the “Acrylite 210-0” type or of the “Plexiglas 2423” type is used to form the filter 23 allowing red and infrared radiation to pass through and ensuring the tightness of the interior of the device in the "toric" shape. An acrylic sphere 19 mm in diameter may constitute the optical element 56-57, although glass may be used in an equivalent manner. The width of the slot 62 is 0.356 mm. The width of the frontal “converging lens” of the hemisphere 57 being approximately 7.6 mm, a light beam approximately 7.6 mm wide, coming from the filament of the lamp 28 (of the GE type No. 194 ) crosses the localization zone and arrives via the slot 62 on the photodetector 60 which can be compatible, from the spectral point of view, with the radiation source 28. In the preferred embodiment, the photodetector 60 comprises a silicon photodiode of the "VACTEC VTS-4085H" type.

In the circuit 70 shown in FIG. 5, the input energy applied to the terminals + V and 0V is in the form of a direct current under voltage of 12 volts, with a nominal current of 0.35 amperes, regulated at 5%. A lamp 71 is connected directly to the 12 volt voltage. A capacitor 74 is mounted in parallel with a motor 75 in order to suppress interference. This capacitor is preferably of the high frequency and broadband bypass type, for example a metallized polyester capacitor, from 0.1 to 0.01 microfarad. Resistors 72 and 73 reduce the direct voltage from 12 volts to a nominal positive direct voltage of 5.7 volts to establish the desired speed of rotation of the motor 75. This speed is high enough to establish the desired analysis frequency, while being low enough to ensure a long engine life and to facilitate data processing. A wide range of rotational speeds can be obtained by means of a suitable DC or AC motor, controlled by an appropriate source of DC or AC voltage. In some applications, a synchronous motor is preferred, while in other applications, a stepper motor is preferred. The first ensures a constant frequency of analysis, while the second quantifies the location range without the need to perform software calculations. A suitable DC motor, suitable for the preferred embodiment shown in FIG. 1, may be of the “MABUCHI RF-510T-12620” type having a nominal speed of rotation of 2400 rpm. A photosensitive sensor 76 is connected to an amplifier assembly 77.

The amplifier 77 shown in FIG. 6 comprises five separate sections of a six-part inverter of the “74C04” type with an oxide-metal semiconductor with complementary symmetry. Pin 7 of the inverter 74C04 is connected to line 0V and pin 14 of the in-

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pourer 74C04 is connected to the positive line, more particularly to the cathode of a diode 81, so that the inverter 74C04 is subjected to a voltage of 12 volts, reduced by the voltage drop produced by the diode, which establishes a voltage Vcc of approximately 25 11.3 volts. Alternatively, operational amplifiers 86, 91, 92, 99 and 100 can be used, with appropriate circuit modifications, each consisting of a Texas Instruments component “TL081”, of a part of a Texas Instruments component “TL084 Or a National Semiconductor "LM308" amplifier. The first part of amplifier 77 is a voltage amplification stage in which a resistor 85 of 2.2 megaohms establishes the gain between the input current and the output voltage. A capacitor 84 of 10 picofarads eliminates high frequencies in order to reduce noise. A resistor 85 also maintains the reverse bias voltage of the photosensitive cell. The output of this stage is connected to an input resistance 89 of a second stage by polarized capacitors 87-88 of 10 microfarads, mounted back to back or, alternatively, by a non-polarized capacitor of 10 microfarads. A second operational amplifier 91 is connected to a reaction resistor 90 of 1 megohm and, with a resistance 89 of one hundred kilohms, it achieves a nominal voltage gain equal to 10. The output of this amplifier is connected by a capacitor 95 of 0.1 microfarad at a 10 kilohm resistor 96, an operational amplifier 92 and a diode 97 (1N914). The operational amplifier 92 and the diode 97 are intended to block the signal so that it cannot become positive at the point of polarization of the amplifier (nominal Vcc / 2). Resistor 93 of 470 kilohms maintains the output of capacitor 95 against the blocking level. Elements 92, 93, 96 and 97 constitute a direct current restorer. The 50 restored DC signal (the most positive DC level of which is at potential Vcc / 2) is applied to a Schmitt 98-101 flip-flop. Operational amplifiers 99 and 100 are connected, in the Schmitt flip-flop, to a reaction resistor 101 of 4.7 megaohms and to an input resistor 98 of 220 kilohms. Unè 55 resistor 94 of 1,5 megohm polarizes the point of the Schmitt rocker opposite the input of resistance 98 at a slightly negative value compared to the baseline of direct current established by the direct current restorer. Resistor 101 establishes hysteresis with resistor 98 of 220 kilohms which also affects 60 the input sensitivity. Two resistors 102 and 103 of 470 ohms, as well as diodes 104 and 106 (1N914), protect the output against discharges of static electricity or other accidental stresses. An electrolytic capacitor 105 of 10 microfarads serves as a supply filter.

65 The diode 81 provides protection against deterioration due to accidental reversal of the polarity, and it can also assume the function of rectifier in embodiments supplied with alternating current.

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In the circuit shown in fig. 6, the diode 76 behaves like a current source controlled by light.

During operation, when the assembly 48 with analyzer and detector of FIG. 1 is directed or focused on screens 18 and 19, the direct current restorer blocks the signal at Vcc / 2. This voltage corresponds to the most positive input applied to the Schmitt rocker of the circuit. The 1.5 megaohm bias resistor 94 has the effect of applying a positive net voltage to the input of the Schmitt trigger in this condition, and the output is therefore close to the line +12 volts (maximum output) of fig. 7. When the analyzer traverses the range without obstacle, under direct or reflected light from the lamp 28, the level of the photodiode signal oscillates in a relatively negative manner. The output signal near capacitors 87 and 88 becomes relatively positive and the output signal of capacitor 95 becomes relatively negative. The output signal from the DC rectifier therefore becomes negative at the nominal level Vcc of the rectifier. The net input signal applied to the Schmitt 98-101 flip-flop becomes negative from the lower trigger level and the final output signal becomes equal to the 0 volt line (minimum voltage value, basic position) of the output, as shown in fig. 7. In the event that an object such as object 52 appears and absorbs or blocks the radiation during part of the analysis, as shown in FIG. 1 where a beam 14 of rays is blocked, for this part of the analysis, the output of the photodetector then returns to its “black” level, the output signal of the first amplification stage becomes relatively negative, the output signal of the second amplification stage becomes relatively positive, and the signal restorer returns to the baseline Vcc / 2, as shown in fig. 7, the output signal passing into its first logic position (maximum output position) as shown in 200, 201 in FIG. 8.

Therefore, fig. 7 shows the positions of the screens 18 and 19 when no object interferes with the distribution of the radiant energy over the location area. The screen parts 113 and 111 of FIG. 7 are simply extensions of the same relatively large screen 19, while the representation 112 of the signal corresponds to the display of the logic value 1 (maximum exit position) of the screen 18 which is smaller, around the assembly 48 with analyzer and detector. The position along the X or Y coordinate axis, when an object is in alignment, determined by modification of the light arriving at the photodiode 60, is indicated respectively by the variable X (115) and by the variable Y ( 114).

Fig. 8 represents a waveform typical of the output signal of the device when an object is placed in the window 21 of the location area, for example the object 52 shown in FIG. 1. Output signals 119 to 121, of logic level one, correspond to the blocking of light by the screens 18 and 19, as described above. Other output signals 200 and 201, of logic level 1, are represented as being located respectively in the analysis zones X and Y 115 and 116. These output signals correspond to the blocking of light by an object located in window 21 of the location area.

Due to the relationship between the angle of rotation and the analyzer and the position in the range along the X and Y coordinate axes, it is possible to deduce from the position and width of these output signals 200 and 201 of logic level 1, the position and the dimension of the object interfere 52 in the location window 21. In particular, the offset between the rising edge of the output signal 200 and the zero or starting point of the analysis X 115, offset which is the distance designated in XI in FIG. 8, corresponds to the position of the edge of the interfering object 52 closest to the zero point on the X axis of the window 21 of the location area. Consequently, by knowing the functional relationship between the analysis angle, in degrees, represented by this offset XI, and the corresponding linear displacement along the axis X of the window 21 of the location zone, it is possible to determine the actual position of the object 52. Similarly, the position of the object 52 along the Y axis can be deduced from the offset Y1 of the rising edge of the signal 201 relative to the zero or the zero position of analysis Y 114.

Additional information can be obtained from the waveform of the output signal shown in fig. 8, concerning the dimension of the interfering object 52 with respect to the X and Y axes. In particular, the width of the signal 200, indicated in delta X in FIG. 8, corresponds to the width of the object 52 relative to the X axis. Similarly, the width of the signal 201, indicated in delta Y, corresponds to the dimension of the object 52 relative to the Y axis Consequently, by knowing the relation between the angular displacement represented by delta X and delta Y and the corresponding linear displacement along the axes X and Y, one can determine the dimension of the object 52.

Fig. 8 also shows an offset part 210 situated between the falling edge of the output signal 119 and the represented start point of the analysis X 115. Similarly, an offset zone 211 is represented between the end point of the analysis X 115 and the rising edge of signal 120, an offset area 212 being located between the falling edge of signal 120 and the start point of the analysis Y 114. Finally, an offset area 213 is shown between the end point of the analysis Y 114 and the rising edge of signal 121.

These offset zones 210 to 213 correspond to uninterrupted light signals which are transmitted externally to the window 21 of the localization zone, for example along a part immediately external to its periphery, from the light source 28 towards the analyzer -detector 48. The existence of these light signals results from an output signal of logic zero level, of fixed duration, immediately preceding and immediately following the X and Y analyzes. These signals can therefore be used to calibrate the detection circuit and / or interpretation, for example to define the existence and the exact dimension of the X and Y analyzes 115, 116. It should be noted that, although these signals which cannot be interrupted are provided for the starting and ending points. end of the two analyzes X and Y in the embodiment whose output signal is shown in fig. 8, other embodiments allow a number less than all of these possible calibration signals to be used, as desired.

Fig. 9 represents the relative voltage levels existing in a typical output signal before the start-up of the part of the circuit constituting the direct current restorer. In particular, the logic level one of output 141 is represented as being lower than the supply voltage V (131) and greater than half, 1/2 V, of the supply voltage (132). The zero logic level 140 is shown to be greater than 0V, but less than half 1/2 V of the supply voltage (132). In this way, the signal can be considered as "overlapping" the supply half-voltage.

After the DC restoring circuit has been activated, the zero logic level 145 of the resulting signal is close to the zero reference voltage, as shown in fig. 10. In addition, the resulting logic level 135 is substantially equal to half of the supply voltage, 1/2 V (132).

This resulting signal can therefore be processed by the circuit's Schmitt flip-flop, as described above. Fig. 10 shows the relative voltage levels C and D with respect to the cut-off points of a typical Schmitt rocker stage. As can be seen, this resulting waveform can be processed by such Schmitt toggle devices in order to accurately indicate the transition points regarding the desired position information.

Fig. 11 shows a mirror 187 with stepped steps with 29 facets, of special design, in which the crests of the mirrors have a constant dimension from one mirror to another, namely, in this case, 5.08 mm.

In the embodiment of FIG. 11, the following angular relationships are noted:

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It should be noted that facets such as those indicated in 191 in fig. 11 or in 155 and 156 in fig. 12 may be substantially flat or curved, as shown in phantom, in order to focus the light they reflect. In addition, the number of surfaces used in a particular application can be optimized according to production possibilities, costs, edge losses, resolution and depth of the rungs. However, the particular design of FIG. 11 makes it possible to display a linear output due to the possibility, for the detector and analyzer assembly, of "reviewing" or focusing on respective equivalent distances in the window of the location zone, as a function of the analysis angles radial, substantially equivalent, respective. The particular embodiment of this mirror with stepped steps also makes it possible to adjust the intensity, so that this intensity is substantially equivalent over the entire extent of window 21, whatever the position of the coordinates reviewed. In the case of mirrors that are less deep than that shown in fig. 11, for example as shown in FIG. 12, a trigonometric or other function must be used with the display device, because the position of an object then becomes a non-linear function of the radial angles of analysis under which the object is detected.

With regard to resolution, it is necessary to establish a spacing step between the facets of a particular mirror, less than the smallest object that one wishes to define. Alternatively, the facets of the mirror can be tilted to form a parallelogram to eliminate the shadows. In particular, as shown in figs. 21A to 21C, minor shadow areas 253 may appear between the reflective areas 254. These shadow areas may result from the mutual obscuration of the individual facets of the mirror or from edge effects of the Fresnel mirror configuration. No radiant energy is emitted or received in these gray areas. Although the shaded areas 253 are of little consequence vis-à-vis objects having dimensions significantly greater than the width of said shaded areas 253, it is possible that small objects fall entirely in such an area d shadow and are therefore not detected. For example, if the object 52 enters the reflective zone 254a of the mirror with steps in normal steps shown in elevation in FIG. 21 A, this results in blockage of light corresponding to a shaded area 263, and this is detected. However, if

30 the object enters one of the shaded areas 253, no blockage of light results, as indicated at 264, and the object is not detected.

To avoid the risk of an absence of detection of objects which are perpendicular to the location zone 21, the individual mirrors 35 can be tilted so that the surfaces of the facets form parallelograms as shown in elevation in FIG. 21B. By choosing an appropriate angle of inclination, it is possible to establish a configuration such that even narrow objects produce at least partial blockage of one or more reflecting areas 253b, 40 as indicated by the shaded area 265, even if d other parts of the object fall into the shaded areas 254b, for example an area 266. However, excessive tilting can result in decreased accuracy and resolution, since all inserted objects can then intercept two adjacent areas. This is glossy in FIG. 21C where an object 52 is detected in two adjacent zones as a result of the presence of areas 267, a zone 268 not being in alignment. Finally, although in the preferred embodiment the inclination of the facets of the mirrors of the detectors is designed so as to be the equivalent reflected image of the inclination of the facets 50 of the distributors so that light beams of parallelogram section are distributed and received, other configurations are possible. For example, it is possible to give a relative inclination opposite to the facets of the collector in order to ensure additional mixing.

In another embodiment of the invention, an optical element 57 is fixedly oriented towards the screen 29 and the screen 18 is eliminated. Mask 61 is not necessary. Detector 60 is a CCD110 linear image detector from Fairchild Semiconductor, or an equivalent component, and it forms, in combination 60 with an appropriate circuit and element 57, both a selective aiming device and a device detection.

In another embodiment of the invention, the device for selective targeting of certain parts of the transmitted radiant energy is arranged at other points along the transmission path 65 of the radiant energy. For example, instead of using a rotary “analyzer-detector” assembly, as described above, a fixed detector can be used with an analyzer-emitter-projector. As shown in fig. 2, in the analyzer embodiment

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and emitter, the photosensitive cell 60 used previously becomes a light source 60, the elements 61, 62 and 53 to 57 having the same structure as that described above.

The analyzer-transmitter 48 can replace the assembly (48) with analyzer-detector between rows 41 and 42 in order to transmit the radiant energy through the “window” 21, in a direction opposite to that indicated by the arrows in fig. 1. The transmissions and or modifications of the energy thus transmitted are captured by a fixed assembly 28 with a photocell situated inside the screens 27 and 29. In this embodiment, the manifold assemblies become distributor assemblies, and vice versa.

Alternatively, an electrochemical, electromechanical, mechanical or electronic shutter, for example liquid crystal display elements or slots displaced by a loudspeaker, a coil or piezoelectric transducers, can be interposed at suitable points on the along the radiant energy transmission path to allow selective targeting of the transmitted radiant energy emissions. Fig. 22 illustrates such a variant using an electronic analysis device cooperating with the detector. Liquid crystal band filters 270 are placed in the path of the beams of radiant energy. As shown in fig. 24, the band filters comprise several adjacent parallel liquid crystal elements 271, of the transmission type. These individual bands are oriented so as to extend in optical alignment between the radiant energy detector and the collectors 42, 41 so that each individual mirror facet of the collectors 42, 41 is in alignment with one or more of the bands 271 of the filtered.

In operation, a single element, for example the element 272, is made transparent to the radiant energy, while other elements 271 are made opaque to this energy. Thus, the transmitted radiant energy is absorbed by the band filter 270, except the part of the energy which corresponds to a beam 273 located in a single location. By successively and sequentially making the individual elements 271 transparent, an electronic analysis of the received radiant energy is obtained.

In the preferred embodiment illustrated in FIG. 22, band filters 270 are placed near the detector, so as to be close to the point of convergence of the light beams. In this way, the linear dimensions of the band filter 270 can be kept to a minimum, which reduces manufacturing costs. In addition, as illustrated in figs. 22, in the preferred embodiment, the liquid crystal band filter 270 carries a metallic coating so that it can be inserted into a corresponding socket 273. An electronic control device 274 is mounted near the socket 273 and connected to a printed circuit 276 applied to the mounting substrate 275, which results in an inexpensive production in one piece. The liquid crystal band filters 270 can be multiplex or direct control types.

The electronic control device 274 of the preferred embodiment causes an element-by-element analysis, first of the liquid crystal band filter 270 placed in the x-axis radiating energy field, then of the corresponding filter 270 placed in the y-axis field. This can be repeated continuously, allowing light from a single x-axis or y-axis relative position to reach the detector at a given time. In this way, it suffices to use a single radiant energy detection element. Alternatively, the band filters 270 can be analyzed simultaneously, individual detectors being used with each of them to simultaneously determine the positions in the x and y coordinates. Analysis rates equal to twice the frequency are thus possible.

Fig. 23 shows a preferred embodiment for a single detector configuration for use with, for example, the electronic analyzer shown in FIG. 22. An optical element 56 intercepts the radiant energy which passes through the transparent elements of the band filters 270 and transmits this energy by reflection and refraction to a detector 277. The optical element 56 is preferably made of plastic, by example an acrylic plastic having a refractive index of about 1.5. Other plastics or glass can be used. The optical element 56 comprises a sphere 281 in which a cone 280 of 45 is produced by milling. The conical surface resulting from the cone 280 advantageously has an optical polish.

The light transmitted by the band filters 270 arrives at the element 56 and is refracted by the spherical element 281, reaching the surface of the countersunk cone 280. Due to the differences between the refractive indices of the material of the sphere 281 and ambient air, a total refraction occurs on the surface of the cone 280, thus directing the light approximately axially through the sphere 281. This light is further refracted by the sphere 281 and is focused by the latter on the sensing element 277. Due to the radial symmetry of the optical element 56, light from any radial direction is similarly refracted, reflected axially and detected by the element 277. Alternatively, other methods known in the art can be used to collect and detect the radiant energy transmitted by the band filters 270.

Fig. 13 shows another embodiment of the apparatus according to the invention in which several light-emitting diodes are provided in order to assume both the function of radiating energy emission elements and distribution elements. In particular, a large number of light-emitting diodes are arranged along each of two of the axes of the location area window 186 so that the radiant energy that they emit is transmitted in substantially parallel beams passing through the location window 186 . These light-emitting diodes are indicated in fig. 13 by the reference numerals 163, 164, 165, 166, 167 and 168, for example. The beams thus produced can be channeled by the use of a skeleton frame 181 having several openings 180. Rows 161 and 162 of integrated collectors are intended to reflect in an equivalent manner the transmitted light (or the absence of this light ) to a detection device 182 which includes photodetectors 183 and 184 mounted back to back. As a variant, it is possible to use the configuration of detectors shown in FIG. 23. Skeleton frames 181, which can be macro or micro-shutters and which completely surround the location area 186, are intended to limit the transmission of light in the form of parallel beams.

To selectively target or analyze parts of the radiant energy and establish a frame of reference with respect to which one of the beams of light emitting diodes is stopped in the event that an object appears in window 186, the light emitting diodes are themselves supplied by pulses, in successive order, at a desired rate, in order to produce a calibration signal in time similar to that of the embodiment of FIG. 1. Thanks to this technique as well as by the use, as a variant, of an analyzer-transmitter or of mask filter mask analyzers, only one or two photodetector devices are necessary to “interpret” the characteristics of transmission and alteration resulting from the position of an object in the localization area 186.

Fig. 14 shows the use of the apparatus 20 for optical position localization with a television monitor 201 to form an interactive information input device. In particular, the apparatus 20 is mounted directly on the front surface of the monitor 201 so that the toroidal housing 20a surrounds the television screen 209. The output 204 of the device is connected, in one embodiment, by means of a conductor 207 directly to the input 205 of a microprocessor system 202. Alternatively, a programmable interval timer can be inserted between points A and B. indicated in fig. 14, so that the output 204 of the device is connected to the programmable timer 203 and that the output of this timer 203 is itself connected to the input 205 of the microprocessor. Finally, the interactive loop is completed by the application to the television monitor 201 of an appropriate output signal 206 produced by the microprocessor 202.

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During use, the microprocessor 202 presents, for example, a choice of selections to the monitor 201. These selections appear in the form of regions identified 208, 211 on the television screen 209. The user can then choose from these options and indicate his choice using a finger 210. Alternatively, a suitable stylus can be used.

When the user's finger 210 touches the television screen 209, it also enters the location area 21 of the position location device 20. Data corresponding to the position of this intervening object 210 are transmitted to an appropriate analysis circuit. In one embodiment, the output signal is transmitted directly to the microprocessor 202. In another embodiment, a programmable interval timer 203 is interposed. The interval timer 203 produces output signals corresponding to the respective lengths of the "work" and "rest" parts of the received signal. As described above, these periods of time “work” and “rest” correspond to the position and the size of the intervening object 210. Although the microprocessor 202 can itself perform the necessary synchronization interpretations, the use of a programmable interval timer 203 may be preferable to reduce the computational load of the microprocessor 202.

By correlating the received data regarding the position of the object 210 with the displayed selections 208, 211, the microprocessor can determine which selection has been chosen and an appropriate response can be triggered. In a preferred embodiment, the selected selection can be highlighted as indicated by a choice element 211 in order to provide a visual response to the operator, indicating to him that a selection has been or will soon be recognized by the microprocessor 202. In this way, an inexpensive programming or data entry device is obtained, while being extremely flexible and easily usable, which saves the user from having to enter by keyboard, this operation can be embarrassing, confusing or intimidating.

Under certain conditions, it may be desirable to be able to have a visual corresponding to the position of an intervening object other than that described above. In an embodiment shown in FIG. 15, an interface 220 produces an output signal on a television monitor 201, this signal corresponding to the location of a intervening object 210. For example, the part 212 of the television image corresponding to the position of any intervening object 210 can be highlighted. In this way, we obtain a direct graphic representation of both the size and the position of all intervening objects.

Fig. 16 shows other means for visually displaying the output information from the optical position location device 20. In particular, the output signals of the device, such as those shown in FIG. 5, can be applied to the input of an oscilloscope 222 by means of input lines 225. To obtain a stable and constantly updated display, it is necessary to repeatedly trigger the oscilloscope 222 at the same point during the display of each of the successive output waveforms. This can be achieved using a synchronization signal extractor circuit 221, the output of which is connected by means of synchronization lines 224 to the input of the oscilloscope synchronization signal 222. A stable representation 223 of the The waveform of the output signal is thus displayed on the face of the cathode ray tube of the oscilloscope, a representation from which the desired data can be measured.

A preferred embodiment of the synchronization signal extractor circuit 221 of FIG. 16 is shown in fig. 17. The circuit includes a negative integrator comprising an amplifier 230, a reaction resistor 233 in parallel with a reaction capacitor 232, and an input resistance 231. The negative integrator is connected to a clipping and detection circuit comprising a transistor 234, a storage capacitor 236 and a leakage resistance 237. The output signal is produced across a collecting resistor 235.

In operation, the output of amplifier 230 is initially at a high positive level. Upon application of a positive input signal, the negative integrator performs an average negative time integration of the input signal, which results in a decrease in the output voltage of amplifier 230. The values of the input resistance 231, the reaction resistance 233 and the reaction capacitor 232, as well as the gain of the amplifier 230, are chosen so that the saturation time of the resulting negative integrator is some little longer than the duration of the longest expected high level input signal. As shown in fig. 8, these high level input signals appear when the light is stopped by the detector element, for example the screen 18 of FIG. 1. In the preferred embodiment, the longest high level input signal corresponds to the blocking of the light by one of the light shutdown screens, for example the screen 18 of the fig. 1.

A peak charge storage capacitor 236 is positively charged by a leakage resistance 237. The time constant of the resulting circuit is chosen so as to be substantially greater than the duration of a full rotation of the analyzer optical. In the preferred embodiment, this time constant can be equal to ten times the duration of a single rotation. In this way, the leakage resistance 237 does not cause a noticeable change in the voltage of the storage capacitor 236 during a single cycle of circuit operation.

Besides serving as a peak hold circuit with the capacitor 236 and the resistor 237, a transistor 234 assumes a detector function. In particular, the synchronization signal extractor circuit is designed to recognize the longest high level input time corresponding, as indicated, to one of the light shutdown screens. This longest lasting input signal brings the output signal of the amplifier 230 of the negative integrator to its lowest level. At this time, transistor 234 briefly becomes conductive, restoring the peak level of capacitor 236. In addition, the resulting collector current,

passing through the collector resistor 235, has the effect of producing an output voltage signal which can be used to trigger the oscilloscope 222. In this way, an identical reference point is established in each of the successive waveforms .

In addition to determining the position and the dimension of an object relative to the coordinate axes of the device, an embodiment of the invention is capable of giving an approximation of the penetration depth of an opaque object or, as a variant , the height of objects whose length is less than the depth of the measurement field itself. These determinations can be extrapolated from data concerning the strength of the signals received. As shown in fig. 18 ', the individual light rays, which include the position determination rays indicated above, can have a fixed and significant “thickness” or depth 50 perpendicular to a plane described by the measurement axes themselves. In the preferred embodiment, this value can be of the order of 7.6 to 12.7 mm, although it appears that other depths are possible. The light which is distributed, for example, by the distributors 40 and 32 of FIG. 1, can advantageously have 55 substantially the same intensity over the entire depth of the resulting beams. In this way, in the case of opaque objects wider than the particular light beam, the intensity of the non-stopped light received by the detector is in inverse relation to the average depth of penetration of the object. For example, an object 52b, 60 introduced approximately halfway into the localization region 21, intercepts about half of the incident light rays 242 and therefore allows the remaining half of the light rays 243 to reach the detector. As shown in fig. 19, the resulting output signals 200b, 201b, corresponding to the non-intercepted part 65 243 of the incident light 242, have a corresponding reduced level compared to the output signals 200a, 201a which would result from a complete shutdown of the light, for example by object 52d.

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To use such penetration depth information, it is necessary to retain the analog DC level of signals 200 and 201. In the circuit shown in fig. 6, these intermediate levels are eliminated by the Schmitt rocker described above. Consequently, in the preferred embodiment to be used with an indication of penetration depth, the Schmitt rocker is replaced by the circuit shown in FIG. 20. In particular, the inverters 99 and 100 are configured in linear amplifier stages by means of input resistors 98, 251 and reaction resistance 250, 252, respectively. The output resistor 102 is retained, although the bypass resistor 94 is suppressed. The resulting linear circuit is mounted between nodes 260 and 261 in fig. 6 in place of the Schmitt seesaw.

Finally, it may be desirable to use techniques known to those skilled in the art for automatic gain control and compensation of the linear output information, in order to make corrections taking account of variations in the l radiant energy emitted by the element 28. The calibration beams indicated above, passing outside the location region 21 corresponding to the offset regions 210-213 of FIG. 8, can advantageously be used for this purpose.

8 sheets of drawings

Claims (2)

656731 2 CLAIMS 1. Optical position location apparatus for locating the position of one or more objects (52) along one or more coordinate axes of a defined location area, as well as determining other measurable parameters of the object or objects such as their dimensions with respect to one or more coordinate axes, the apparatus comprising means (28) emitting radiant energy, means (48) for detecting radiant energy, means intended distributing the radiant energy emitted by the emission means over a location area, from a position located along a first part of said area, collecting means (41, 42) placed along a second part of the location zone, substantially opposite to the first part, and cooperating with the distribution means so as to receive the radiant energy which they distribute and to redirect it towards the detection means, and means intended for selectively target certa ines parts of said radiant energy distributed and received in order to describe the properties of radiant energy which have been modified as a result of the presence of the object in the localization area, said properties corresponding to the position of the object in this location area as well as other parameters of said object, the means intended to selectively target certain parts of the radiant energy distributed and received comprising an electronic analyzer (48) interposed on the emission path of the radiant energy and capable of exposing the radiant energy detection means to the radiant energy transmitted through individual selected parts of the location area, the apparatus being characterized in that the electronic analyzer comprises a band filter (23) with crystals liquids, of the transmission type, comprising several adjacent parallel filter elements (270) which can be made individually substantially opaque or sensiblemen t transparent by associated electronic control means. 2. Apparatus according to claim 1, characterized in that it further comprises a fixed optical element (281) which comprises a transparent section, substantially hemispherical, and which has a conical part (280) removed from its center and whose axis corresponds to the axis of the hemispherical section, the conical surface resulting from the optical element having an optical polish so that the incident radiant energy, arriving at this optical element from various radial positions, and refracted and redirected by said element optical, sort of the latter substantially along said axis, the means (277) for detecting radiant energy being arranged along the axis of the optical element in order to receive the redirected radiant energy.