FR2653925A1 - Display device with a built-in photovoltaic generator - Google Patents

Abstract

The invention relates to display devices provided with equipment for night-time illumination of the displayed indications. The device which is the subject of the invention includes one or more indicating faces, each produced on a single support of appropriate material. One indicating face includes, on this single support, one or more parts acting as a background and one or more parts acting as indications. The invention is characterised in that all or part of the background of the indicating plate in itself constitutes a photovoltaic sensor manufactured integrally on the support material.

Description

 The present invention relates to display devices such as indicator panels, street signs, professional signs, etc., provided with night lighting equipment for the displayed indications.

 A certain number of display devices such as road signs, urban display panels, street signs, etc. are equipped with a night lighting device supplied with electric current by connection to the mains. This limits their establishment to sectors supplied with electric current on the one hand, and, their generalization is in all cases limited due to the high cost of installation and maintenance on the other hand.

 In order to overcome these drawbacks, one solution consists in equipping these display devices with an autonomous source of power supply such as a photovoltaic generator. And it was possible in this way to produce road signs, relatively large, and, for example, street number and / or patronymic name devices, small.

 A characteristic common to existing embodiments lies in the existence of a photovoltaic panel - active part of the generator - constituting a particular part, distinct from the indicator panel proper. This usual characteristic, in addition to possibly some aesthetic drawbacks, exposes the entire device to degradation, and, in particular to the theft of the photovoltaic panel for other uses than that for which it was intended.

 Recent developments in the techniques for producing photovoltaic solar panels, using semiconductors such as amorphous silicon or even gallium arsenide deposited in a thin layer on supports such as glass or a plastic film, make it possible to envisage a another solution to the problem of the autonomous power supply of various display devices. We propose that the photovoltaic generator become an integral part of the display device, and this not by integration into a single set of parts of different nature and origin, but by integration from the manufacturing stage of the indicator plate functions and this photovoltaic sensor.

 To this end, the display device which is the subject of the invention comprises one or more indicator faces, each produced on a single support of suitable material. An indicator face conventionally comprises, on this single support, one or more parts acting as a "background", generally dark in color, and one or more parts acting as indications, generally light in color, in the form of letters, figures, symbols, drawings, etc. The invention is characterized in that all or part of the "bottom" of the indicator plate in itself constitutes a photovoltaic sensor, which has come from manufacturing on the support material.

 The electrical energy produced during the day is accumulated in a storage battery via an electronic charge-regulating device, and restored at night, on command of an appropriate detector device, for the supply of a lighting system for the indications of the display device. Depending on the type of technique retained for the realization of the "indications" parts of the indicator plate, we will retain appropriate techniques! required lighting.

 As a first example of an embodiment, the "indications" can be painted on the support using a semi-transparent clear paint allowing them to stand out normally on the darker "background" during the day, and to leave during the night pass them through to the observer the light of a suitable lighting source placed inside the housing of the display device, and supplied with electrical energy by the integrated photovoltaic generator previously described. It goes without saying that all the characteristics of the device will be optimized so as to obtain a sufficient night-time brightness of the "indications" for a limited lighting power in relation with the same compulsory limits of the integrated photovoltaic generator by virtue of its imposed dimensional characteristics. by the size of the sign, and by its random solar exposure.

 However, it is also possible to envisage other more elaborate embodiments of the parts serving as "indications" of the indicator plate and, by adopting the same technique of deposition in thin layers (of amorphous silicon for example) as for the or the photovoltaic sensor parts of the "bottom", carry out the "indications" as a photo-emissive device with semiconductor (deposit of gallium arsenide for example), or as an electro luminescent device (deposit of zinc sulfide for example) possibly completed by a photoconductive layer according to the PC-EL technique.

In these elaborate embodiments of "indications", the night lighting system will consist "simply" of supplying their electrodes with electrical energy from the photovoltaic generator. In this last elaborate embodiment, it is the whole of the indicator plate which is presented as a "printed circuit" of a particular kind, totally unsuitable for any use other than that of display for which it is intended. .

 We can thus easily imagine the production according to the last embodiment presented of street name indicator plates, using a fully automatic machine supplying indicator plates in series, the bottom of which is an amorphous silicon photovoltaic sensor and the indications are photo-emissive or electroluminescent. A resin-encased case would only allow the locations of a plug-in and replaceable battery and electronic card to appear on the rear panel.

 However, this is only an extreme form of development of the invention, which in many ways also includes the autonomous night lighting of various display devices provided with integrated photovoltaic generators.

Claims (8)

REYEND TIONS  1) Display device with night lighting of the displayed indications, characterized in that all or part of the background on which the indications of the indicator plate (s) which stand out are detached, constitutes a photovoltaic sensor produced from manufacture on the same support as the indications.  2) Device according to claim 1 characterized in that a storage battery is connected to the photovoltaic sensors via a charge regulator device, constituting a photovoltaic generator.  3) Device according to claim 1 or claim 2 characterized in that the indications of the indicator plate (s) are painted on a transparent support using a paint becoming transparent for a certain intensity of lighting.  4) Device according to claim 3 characterized in that one or more light sources electrically supplied at night by the photovoltaic generator are arranged in the rear face of the indicator plate (s)  5) Device according to claim 1 or claim 2 characterized in that the indications of the indicator plate (s) are made in the form of a photo-emissive semiconductor device  6) Device according to claim 1 or claim 2 characterized in that the indications of the indicator plate (s) are made in the form of an electroluminescent device  7) Device according to claim 1 or claim 2 characterized in that the indications of the indicator plate (s) are made in the form of an electroluminescent device with additional photoconductive layer.  8) Device according to claim 5 or claim 6 or claim 7 characterized in that the device; photo-emissive or electroluminescent indicators are supplied with electrical energy at night by the photovoltaic generator.