FR2501884A1 - Variable-information roadside display panel - uses fibre=optic coupling of miniature dot matrix array to larger modules and laser illumination - Google Patents

Abstract

The panel incorporates a display screen (12) on the front face of its casing (11) with e.g. a matt black finish for improved contrast. A laser source (1) emits a monochromatic pencil of e.g. red-orange light which is deflected and modulated (2) under control (3) from a keyboard or computer terminal to form the message characters. After deflection the beam strikes a linear array of receiving modules (5) each having e.g. seven rows and five columns of light-sensitive points, all connected by optical fibres (7) to an emitter (8) which forms one module of the screen for displaying one character. The receiving array (5) is a miniature counterpart of the emitting array (8) which reduces the beam deflection requirement.

Description

250 1884

  Variable signaling panel and method.

  The present invention relates to a panel and a method intended for variable signaling, that is to say the display of information which can be modified at will and

  shown in light form with sufficient intensity

  health to remain visible day and night whatever

  or the exterior brightness. Such signaling devices

  light or display are applicable in particular

  especially for road signs and display

  information at stations, airports, or the like.

  When you want to display variable information depending for example on weather conditions or

  traffic conditions for road signs, we use

  reads electrical devices controlling light sources

  neuses which are generally incandescent lamps and whose selective ignition allows to write on a panel,

  letters, numbers or signs representing the desired information

  rée. However, these light display devices are difficult to read given their low light and result in very high consumption of electrical energy and costs.

  frequent and high maintenance.

  French patent 2,315,739 has already been used, in order to overcome this drawback, to use a laser projector whose light brush is suitably oriented by a

  deflection system before being projected on a screen

  tro-reflective produced using a plurality of mirrors

  reflective. If we actually find that we

  thus holds sufficient light energy on the various points of the retro-reflective screen provided that a relatively high power laser is used, it is however observed in practice that this device does not provide a visible display under all conditions and in particular in broad daylight when the environment of the panel is also reflected by the screen composed of reflecting mirrors.

250 1884

  The object of the present invention is to eliminate these drawbacks while allowing the use of a source

  low intensity light and therefore low con-

summation of energy.

  The variable signaling panel according to the invention comprises a light-laser source and means for scanning the light brush emitted by the laser source. The panel includes a set of receiver modules arranged in the

  optical path of the light brush from the balancing means

  yage. Each receiver module comprises a matrix of transparent points which can therefore be successively subjected to the laser light brush as a function of the angle of deflection entrained by the scanning means. A network of optical fibers, the end of at least one fiber of which is connected to one of the points of a matrix of points of one of the receiver modules cooperates directly with all of the aforementioned receiver modules. In addition, a set of transmitting modules each comprising a similar transparent dot matrix but of dimensions very much greater than those of the dot matrices of the receiving modules, forms the

  strictly speaking traffic sign. The other extreme

  mite of the different optical fibers is connected to a point of a corresponding matrix of points of each of

transmitter modules.

  Under these conditions, the light successively collected

  on each point of the different point matrices of the mo-

  of the receptors is transmitted by the fibers of the network

  of optical fibers at each corresponding point of the different

  dot matrix rents of the transmitter modules.

  To widen the visibility range of each of the points of the transmitter modules, it is possible, in an advantageous embodiment, to add to each of the points of the point matrices of the transmitter modules an optical system such as a lens. The point matrices used on the different modules can include any number of points. In practice, preferably 5 x 7 point matrices are used to form letters and numbers in the

  using the 35 points arranged in a rectangular matrix.

  The scanning is done at a speed higher than the persistence

  retinal tance the observer receives the impression of a

  sage fixed. Although the use of such point matrices is

  preferred, we could also realize the reception modules

  sensors and transmitters so that they comprise straight or curved lines which also make it possible, according to the scanning of the laser brush, to obtain the formation of numbers or

  letters representing the variable light message.

  The front face of the sign according to the invention

  tion comprising the dot matrices of the transmitter modules preferably has a dark colored mast coating,

  for example black, in order to further increase the contrast.

  It is understood that in such an embodiment according to the

  vention not using any retro-reflecting screen, a remarkable contrast is obtained between the light points lit by the optical fibers representing the message and the dark background of the road sign. This results in the possibility of producing such a variable luminous message visible day and night using a laser light source of very low power and in particular of the order of l to mW, the laser transmitter then being able to be easily air-cooled and does not require any special device

  cooling for example of liquid circulation.

  The deflection of the light brush from the laser source

  can be performed by any conventional scanning device.

  One can thus use a galvanometric mirror system which allows, by the action of an electromagnetic field on a free rotating magnet connected to a mirror, to obtain vibrations ensuring precise positioning of the deflected beam.

  Tower mirror systems can also be used.

  nant in which a motor rotates a cylinder at the end of which are mounted several small mirrors whose faces are erected and oriented according to the intended application.

  Finally, it is also possible to use deflectors

  to-optics in which a piezoelectric transducer attached to a crystal which may for example be based on tellurium oxide, generates in the crystal a sound wave which modifies the pitch of its diffraction grating. A modification of the

  frl-uene excitation allows the deflection of the light beam

  ne.ux passing through the crystal.

  We can add to the df! Le; rion 'scanning system a dio-positive modulation of the light beam for example in tcut or nothing in order to illuminate at all times only the areas

  of the receiver module considered.

  The control of the deflection device with scanning and optionally of the modulation device can be done by any suitable conventional mroyen such as electronic control or manual keyboard so as to form on the transmitter modules

the desired variable message.

  The optical fibers used can be of the standard type.

  : ique. If you want to increase the visibility of the message

  light displayed on the 9mitter modules it can be easily

  2vt haitable under certain conditions, that each light point of the matrixes of points of the transmitter modules is constituted by the end of several optical fibers juxtaposed, by

  example four fibers per light point.

  To minimize the length of the necessary fibers

  saires, which allows both a saving of material and a decrease in attenuation, that is to say the ability of the fiber to transmit more or less far the optical signal, it is possible to mount the source Laser juicer as well as scanning and modulation means - &. intueIs of the light brush and the receiver modules inside a box, one of the faces of which receives the various transmitter modules forming the actual sign.

  The invention also relates to a signaling process.

  satqun lir.mineuse variable by means of a luminous brush 6mis by a laser source and subjected. the action of a proprietary scanning device, in which a weak laser is used

250 1884

  power, the transmission of the light brush deflected by the scanning means being done by a network of fibers

  optics from a set of material receiver modules

  reading in miniature form the luminous message to be transmitted

  put up to a set of transmitter modules on which light points scanned at a speed higher than the

  Retinal persistence form the variable message.

  The present invention will be better understood from the study of a particular embodiment described by way of non-limiting example and illustrated by the appended drawings, in which: FIG. 1 is a block diagram of a device according to the invention; fig. 2 illustrates a receiver module and a transmitter module used in the device of the invention; and

  1, fig. 3 schematically shows a sign panel

  variable reading according to the invention in the form of a box

  containing all the elements of the device.

  As shown very schematically in FIG.

  1, the device comprises a laser light source 1 emitting

  both a monochromatic light brush for example

  their red-orange which is suitably deflected by a scanning device 2 which may include modulation means. The scanning device 2 is controlled by electronic means of the conventional type represented 2S in the form of the control device 3. The

  command 3 can be connected to a keyboard or a gold terminal

  a dinator not shown in the figure capable of carrying out the scanning and modulation suitable for the formation of the characters necessary for the realization of the desired light message which appears to be fixed to an observer due to the phenomenon of retinal persistence. It will of course be understood that the scanning control means represented by block 3 are adapted to the scanning means represented by block 2 used in each particular case whether it is a vibrating mirror system, a system rotating mirror or

an acousto-optical system.

  After its deflection, the light brush from the dispo-

  scanning device strikes a strip 4 comprising a plurality of receiver modules 5. Each receiver module 5 comprises, as can be seen in FIG. 2 a set of points 6 arranged for example in the form of a rectangular matrix of seven rows and five columns. The different

  points 6 can be successively and alternately illuminated

  res by the light brush from the scanning device 2.

  A fiber optic network 7 directly connects each point 6 of a receiver module 5 to one of the points 9 of a transmitter module 8. The different transmitter modules 8 are

  arranged for example side by side o aligned in a suitable way

  so as to allow the formation of different measures

  wise men desired. Each transmitter module 8 allows for example

  to display a letter or a number by lighting suitable-

  ment a number of light points 9 as shown in FIG. 3 o the letter E is displayed under

example.

  The strip 4 of receiver modules 5 constitutes the repro-

  duction in miniature in a similar form, of all the transmitter modules 8 of larger dimensions. Each receiver module 5 can for example have dimensions of 3 x 2 cm while each transmitter module 8 can have a height ranging for example from 5 to 30 cm. The small dimensions of the strip 4 allow the light beam to strike any of the points 6 of the receiver modules

  for a minimum deflection angle. Note that the different

  rents receiver modules can be arranged according to a

  or according to any other arrangement depending on the

  characteristics of the scanning device 2 and the means of

command 3.

  Each light point 9 of the emitter modules 8 is further equipped with a lens 10 making it possible to open the cone of

  visibility according to the needs of the signage envisaged.

  In particular for road signage, the visibility cone should preferably have an opening of the order of 80 while for signage at a station or an airport an opening cone of the order of 200 will be preferred. The very small diameter of the laser light brush from the scanning device 2 allows precise pointing to each of the points 6 of the receiver modules 5. Scanning at a speed greater than the retinal persistence allows the production of a fixed message on the whole transmitter modules. The inscription of each of the letters can be done according to a continuous path according to the shape of each letter or, depending on the characteristics of the scanning control device, by successively exploring line by line

  each dot matrix. When the light beam

  comes close to a point which must not be lit, the scanning control device 3 emits a signal causing a significant deflection of the light brush which does not light up

the corresponding point.

  In the example illustrated in fig. 3, it can be seen that the traffic sign comprises a box 11, the front face of which is closed by a screen 12 preferably comprising a matt coating of dark color, for example a black coating capable of increasing the contrast. Inside of

  panel 11 is arranged all of the elements of the

  vention. We find indeed the laser 1, the scanning device 2 with its control means 3, as well as all the receiver modules 5 directly connected by the fiber optic network 7 to the various transmitter modules 8 of which only

  one of them has been shown to simplify the drawing.

  The use of a low power laser source of the order of 1 to 25 mW air cooled is sufficient thanks to

  to the means employed in the present invention for obtaining

  high luminance signaling for low power consumption, the assembly can be housed so

  compact inside the housing of a sign panel

reading.

250 1884

Claims (6)

CLAIMS l. Variable light signaling panel comprising a laser light source and means for scanning the light beam emitted by the source, characterized in that it comprises a set of receiver modules arranged in the: optical beam of the light brush from the aforementioned scanning means and each comprising a matrix of transparent dots; an optical fiber network, one end of at least one fiber being connected to one of the points of a point matrix of one of the receiver modules; and a set of transmitter modules each comprising a matrix d of transparent dots, of dimensions very much greater than those of the dot matrices of the receiver iodules, the other end of the different optical fibers being connected to a point of a corresponding dot matrix d one of the transmitting modules so that the light successively collected at each point of the different matrices of points of the receiving modules is transmitted by the fibers of the optical fiber network at each corresponding point of the different matrices of points of the transmitting modules.   2. Variable sign according to the claim   tion 1, characterized in that each point of the point matrices of the transmitter modules comprises an optical system   determining the visibility cone of said point.   3. Variable sign according to the claims   cations l or 2, characterized in that the dot matrices comprise 5 x 7 dots in order to form letters and numbers by means of a scanning at a speed greater than the retinal persistence.   4. Variable signaling panel depending on which one   conch of the preceding claims, characterized in that   that the front face of the panel comprising the dot matrices of the emitter modules has a matt colored coating   dark likely to increase contrast.   -S Variable signaling panel depending on which one-   conch of the preceding claims, characterized in that   that the scanning is carried out by means of a mirror system 250 188 4   galvanometric, of a rotating mirror system or of a acousto-optic device.   6. Variable traffic sign depending on which one   conch of the preceding claims, characterized in that   that each point of the different point matrices is connected   to several fibers of the optical fiber network.   7. Variable traffic sign depending on which one   conch of the preceding claims, characterized in that   that it comprises a box inside which the laser light source, the scanning means and the receiver modules.   8. Variable light signaling method using   a laser source equipped with scanning and modulating means   lation characterized by the fact that a low power laser is used and a network of optical fibers transmitting the light brush suitably deflected by the means of   scanning, from a set of material receiver modules   health in miniature form the light message to be transmitted   put up to a set of transmitter modules arranged   so as to form the desired light message.