FR2586844A1 - Signalling device using light-emitting diodes - Google Patents

Abstract

The present invention is in the field of signalling and its subject, more precisely, is an illumination device especially intended for light signalling for traffic, of the type employing light-emitting light generators such as light-emitting diodes LED characterised mainly in that it consists of: at least a first plurality of LED's 1 arranged on at least one so-called first plate 24, forming a printing circuit chassis, rectifier means 11, 12 for the alternating current intended to supply the said LED with rectified current, and a diffuser 25 made of a substantially transparent material, possibly an ordinary lamp cap, of the screw or bayonet type directly or indirectly integral with the LED plate. Applications especially to warning lights at cross roads but also to signalling by letters, numbers, symbols, etc.

Description

 The present invention is in the field of signaling and more specifically it relates to a light signaling device in particular applicable to intersection lights or the like.

 We know, in terms of road signs, the use of light emitting diodes (LED) as light sources; there is known for example a light device in which green LEDs and red LEDs draw side by side a stopped pedestrian (red LED) and a walking pedestrian (green LED), device arranged at the entrance to the pedestrian crossing across the street. We also know other forms of such light panels flashing or not indicating speed limit, presence of work, etc. In all these cases of application, LEDs are used without an intermediate diffusing surface and this - due to their relatively low brightness.

 The present invention has two essential aims: to provide a very reliable lighting device intended to be immediately substituted for incandescent electric bulbs fitted in particular with the recall lights, that is to say those traffic lights which are at the level of the motorist; by immediate means is meant that having removed a damaged bulb, one can simply put in its place the device object of the invention. Offer a reminder light of a very high reliability and a small thickness intended to replace the current reminder lights operating by means of incandescent lamps.

 According to the invention, in its generality, a lighting device in particular intended for light signaling for traffic, of the type using light emitting light generators such as light emitting diodes (LED), is mainly characterized in that it is constituted by at least a first plurality of LEs; D arranged on a first plate forming a printed circuit chassis, rectifying means for alternating current intended to supply rectified current to said LEDs and a diffuser of a substantially transparent, colorless or very weakly colored, said diffuser comprising at least one face provided with regular reliefs pressed against each other and having dimensions substantially of the same order of magnitude as the exit face of the LEDs.

 The first object fixed to the present invention is achieved by a lighting device comprising the general characteristic mentioned above and further characterized in that said first plate is circular and of a size approximately comparable to that of a lamp with incandescence, in that the first plate is integral and kept spaced at a certain distance from a second plate of the same dimensions, the space between the two plates serving to accommodate said straightening means and other supply members, and in that said second plate comprises on its face opposite to the first plate an incandescent lamp base.

 Preferably, each of said plates is used as a printed circuit support, the printed circuit of the first plate distributing the rectified voltage to said LEDs and being printed on the face of the first plate opposite the second plate, the circuit of the second plate connecting the supply diodes in bridge with said bridge directly receiving the mains voltage via the base; it follows from this particular arrangement that the plates can serve at the same time as a frame, a housing and other structural elements and a circuit element.

 Advantageously, the plurality of LEDs is itself divided into two equinumeric groups of LEDs, which makes the system dual voltage (110 or 220 V) the LEDs of each group being connected in series and according to a preferred embodiment, the LEDs are high brightness type and the number of LEDs in each group is between 40 and 50.

Advantageously finally the second plate can be at the same time the bottom wall of a cylindrical case whose bottom supports on its outer face the base, and whose side wall supports, on its periphery, the diffuser and on its internal face, said first plate. Note also that the
LEDs can be arranged in a curvilinear strip.

It will also be noted that all the constituent elements (LED, rectifier, resistor, base) can be mounted on a single plate.

 In the two preceding advantageous cases, a light source with a physical and mechanical structure was thus entirely comparable to that of an incandescent bulb, but which has the advantage of having the renowned reliability of LEDs, ie a considerably longer life than an incandescent bulb. We know that the light emitted by LEDs is colored; each LED bulb according to the invention will therefore have the corresponding color, red, green or orange to the signaling element with which it is associated.

 The second object fixed to the present invention is achieved by a signaling device comprising the general characteristic stated above and further characterized in that the first plate comprises a triple plurality of LEDs, each plurality having one of the colors red, green and orange, in that the LEDs of each plurality are arranged along a circular surface, in that the diffuser is formed by a single piece of said material, said single piece having substantially the same dimensions as said first plate, and in that a second plate is formed by the bottom of an elongated box, of the same dimensions as the first plate, said box internally supporting said first plate, and supporting, on its periphery, the diffuser and, on the external face of its bottom, means of attachment and electrical relationship. Preferably, the diffuser forming the cover of the housing is shaped in three domes aligned opposite the surfaces circ LED lights. There is thus an igniting device, for recall lights in particular, very flat, very simple to manufacture and very reliable as regards the life of the light sources that constitute the pluralities of LEDs.

 In general, and when the devices of the invention will be used without using traditional colored diffusers, the diffuser, whether integrated or separate, whether it is that of the device replacing a bulb or whether it is that of the three-light signaling device will preferably be slightly curved so as to easily compensate for the directionality of the light emitted by the LEDs and at the same time to have greater mechanical resistance, and the material which constitutes it will be colorless or very weakly tinted; the latter characteristic has the advantage of avoiding the effect of a phantom signal due to an external source of light, for example the sun; the presence of the light emitted by this phenomenon will be white light which cannot be confused with one of the colored lights.

The present invention will be better understood and details will be apparent from the description which will be given of particular embodiments in relation to the figures of the appended plates, in which
FIG. 1 is a schematic front view of an LED device forming a light source according to the invention,
- fig.2 is a similar illustration of the same side view, asec two versions of the bottom,
- fig.3 is an electronic wiring diagram of the LEDs of the device in the previous figures, and their power supply,
- fg.4 is a schematic section of a second version of a device similar to that of fig.1 and 2,
- Fig.5 is a partial section on an enlarged scale of a reflector wall,
- Figs. 6, 7 and 8 illustrate different types of reliefs on the internal face of the reflectors,
- Fig.9- is a schematic section of a three-light device according to the invention, and
- Fig.10 is a front view of the same.

 In FIGS. 1 and 2, a light source which can be substituted for an "incandescent lamp" is constituted in accordance with 3.'invention of a plurality of LEDs 1 arranged on a first plate 2 whose internal face 3 comprises a printed circuit this first circular-shaped plate is secured by means of spacers such as 4 to a second plate 5, the internal face 6 of which also has a printed circuit; a base either with screws such as 7, or with a balonnette such as 8, standardized dimensions, is fixed on the external face 9 of the second plate the space between the first and the second plate is occupied by electronic components such as rectifier bridge 11 and adaptation resistor 12.

 In Fig. 3, a diode rectifier bridge 11 can be symbolically represented which can be supplied with 110 or 220 V alternating voltage, two possibilities of wiring 14 and 15 depending on whether the primary voltage is 110 or 220 V respectively, resistors of intensity adjustment 16 and 17 each mounted in series with LEDs 1 in two circuits, respectively 18 and 19; to fix the ideas, the characteristics of the components are as follows: the rectifier bridge is a 400 V / 1 A bridge, the resistors 16 and 17 are resistors of 1,200 SI / 3 W and the LEDs are of the high brightness type and there are 44 for each circuit 18 and 19.

 The dashed line 20 separates the elements which are above (LED) from the first plate 2 of the previous figure, from the elements (resistor, rectifier bridge, and wiring) which are below.

 In fig.4, a device similar to that of the previous figures differs from it, however, in that said second plate consists of the bottom 21 of a cylindrical case 22, the side wall 23 of which supports on its internal face a plate 24 and on its periphery a diffuser 25 provided with an internal relief; the plate 24 itself supports the LEDs 1 on one side and their supply circuit on the other, while the bottom 21 comprises on one side a printed circuit for the supply members and on the other a screw base 26 for example. The device, or LED bulb, in fig.4 replaces both the incandescent bulb and the traditional diffuser used for example in the recall lights.

 In Figs. 5 to 8, we have illustrated in section (fig. 5) or in plan (fig. 6 to 8) various reliefs of the internal and concave face of the diffusers, thus the section of fig. 5 illustrates reliefs in hollow 27 in the form of a half sphere; in the other figures the reliefs are hollow points, or polyhedra, of hexahedral form (fig. 6), tetrahedral (fig. 7), trihedral (fig. 8). It will be noted that the concave internal surface of the diffuser corresponds to a dome conformation thereof.

Since the LEDs emit a monochromatic light of a color approaching one of the colors required for signaling the square ovens, there is no need for the diffuser itself to be colored. However, it appeared to the Applicant. that it was advantageous to incorporate, either superficially or into the mass of the diffuser, a dye of the fluorescein or eosin type to modify the color of the light emitted by the device and bring it closer to the more conventional color of the intersection lights,
In fig. 9 e 10, a signaling device, in particular for recalling intersection lights, comprises three groups of LEDs 1 each analogous to the group of LEDs of the LED bulbs of fig. 1 and 4., and mounted on a plate single 28 with printed circuit, itself mounted inside a case 29, the bottom 30 of which supports the feed members; the housing is closed by a cover 31 with three domes forming a colorless diffuser; a bottom plate of the housing supports fixing means 32 and electrical connection 33; each of the groups of LEDs emits a light of color corresponding to its position in the device, namely red (P) for the upper group of LEDs, yellow-orange (o) for the intermediate group and
Yellow-green (Vj for the lower group.

 According to the example above, at least one group of LEDs has been associated with a diffusing member, both having a certain configuration, namely that of a booster light; It is obvious that, without departing from the scope of the invention, this association can be given other configurations: for example, those of letters, ciffers, symbols, usual in terms of signaling such as triangles, circles, silhouettes, etc ...

 Although. we have described and / or shown particular firms producing signaling devices conformgs to the invention, it should be understood that the scope of the latter is not limited to these forms but that it extends to any device with the general characteristics set out above.

Claims (2)

1.- Lighting device in particular intended for the signa  lighting for traffic, of the type highlighting  work of electroluminescent light generators  such as light emitting diodes (LEDs), character  get  in that it is constituted by  - at least a first plurality of LEDs arranged on.  at least one plate, called the first, forming a chassis with  printed circuit board,  - means for rectifying the alternating current  intended to supply rectified current to said LEDs  and,  - a diffuser of a material substantially trans-  related, colorless or very faintly colored, said  diffuser comprising at least one face provided with  regular reliefs tight against each other and  having dimensions roughly of the same order of  quantity as the LED output face 2.- Device according to claim 1, characterized  in that said reliefs are  embossed reliefs belonging to one of the forms  geometric including denie sphere and poly  edres  - Device according to claim 1, more special  intended to be substituted in the head of  signaling of a traffic light or the like, at the  light source, usually used in  such ùx, characterized  in that said first pla  that is circt-xlaire and of an approximate size  roughly equal to that of an incandescent lamp,  in that the first plate  is united and kept spaced at a certain  distance from a second plate of the same dimensions,  the space between the two plates used to  house said recovery facilities and other organizations  power supply, and  in that said second pla  that has on its face opposite to the first plate  an incandescent lamp base;  4.- Device according to claim 3, characterized:  in that each of said pla  that is used as a printed circuit board, the  printed circuit of the first plate distributing the  voltage rectified to the said LEDs and being printed on  the face of the first plate opposite the second  plate, the circuit of the second plate connecting in  supply diode bridge said receiving bridge  network voltage directly through  of the base 5.- Device according to claim 4, characterized  in that said plurality of  LED is itself divided into two equinerial groups.  ques de LF.D, the LEDs of each group being mounted in  series 6.- Device according to claim 5, characterized  in that the number of LED's  each group is between 4C and 50; 7.- Device according to claim 4, characterized  in that said second pla  what is the bottom wall of a cylindrical case  whose bottom supports on its outside face the  base, and whose side wall supports, on its  around, the diffuser and on its internal face, said  first plate 8.- Device according to claim 1, characterized:  in that said first pla  that comprises three pluralities of 7.ED, each plurali  tee having one of the colors red, green and orange,  in that the LEDs of each  plurality are arranged along a circular surface  re,  in that the diffuser is  formed by a single piece of said material, said  single piece having substantially the same dimensions  that said first plate, and  in that a second plate  consists of the bottom of a shaped box  elongated, of the same dimensions as the first plate,  said housing supporting, internally said pre  first plate, and supporting, on its periphery, the  diffuser and, on the external face of its bottom,  fixing and electrical connection means 9. Device according to claim 8, characterized  in that the diffuser is  shaped according to three domes aligned opposite desdi  your circular surfaces of the LEDs 10.-Device according to claim 1, characterized  in that said diffuser in  corpores at least superficially a substance  fluorescent.