FR3061604A1 - OPTICAL COMMUNICATION PHOTOVOLTAIC DEVICE - Google Patents

Abstract

The invention relates to a photovoltaic and optical reception device for both the production of energy and the reception of an optical communication, composed of at least two parallel plates (21,22): a first plate (21) partially transparent to sunlight (1) comprising a face on which is disposed a plurality of photoactive areas (31) forming photo detectors dedicated to the reception of modulated light from a modulated light source ( 2) carrying information, said photoactive zones (31) being intrinsically opaque and separated by zones of transparency (61); - a second plate (22) comprising a substrate on which is disposed a plurality of photovoltaic cells (32) dedicated to the production of photoelectric energy and comprising an opaque electrode; characterized in that the active faces of said photoactive zones (31) are facing active zones of said photovoltaic cells (32).

Description

Holder (s):

BIALIC EMILIE.

SUNPARTNER TECHNOLOGIES.

® Agent (s): GLOBAL INVENTIONS.

® PHOTOVOLTAIC OPTICAL COMMUNICATION DEVICE.

(© The invention relates to a photovoltaic and optical reception device allowing both the production of energy and the reception of an optical communication, composed of at least two parallel plates (21,22):

- a first plate (21) partly transparent to sunlight (1) comprising a face on which is arranged a plurality of photoactive zones (31) forming photo detectors dedicated to the reception of modulated light coming from 'a modulated light source (2) carrying information, said photoactive zones (31) being intrinsically opaque and separated by transparency zones (61);

- a second plate (22) comprising a substrate on which is disposed a plurality of photovoltaic cells (32) dedicated to the production of photoelectric energy and comprising an opaque electrode;

- characterized in that the active faces of said photoactive zones (31) are opposite the active zones of said photovoltaic cells (32).

Photovoltaic optical communication device

The present invention relates to communication devices by visible and invisible light (IR and UV) of optical laser communication type and / or of VLC (acronym for "Visible Light Communication") / LiFi (acronym for "Light-Fidelity") type. associated with a photovoltaic energy production device.

STATE OF THE ART

Optical communication devices use light waves to transmit information between two distant points.

Free space optical communication devices generally use lasers or laser diodes as the transmission means, and photodiodes as the reception means. The light beam emitted by the laser or the laser diode is a coherent beam. It can therefore be modulated in amplitude and in phase.

Communication devices using visible light (VLC or LiFi) generally include an LED (or a module of LEDs) forming a transmission means and a photo detector forming a reception means.

The LED provides an inconsistent light signal (Visible / IR / UV), the intensity of which is modulated according to the information to be transmitted. In particular for the visible area, LED luminaires have the advantage of allowing the dual function of lighting and data transmission. Their physical characteristics make it possible to envisage bit rates of the order of Gbits / s for dedicated systems. This LED can consist of a single blue chip covered with a phosphor to allow white lighting, or be made up of several chips (RGYB for example). The first type, with a blue chip associated with a phosphor is predominant in LED bulbs, but it is also often the factor limiting the bandwidth due to the response time of the phosphors.

A blue chip can reach a bandwidth of 20-100MHz, while this same blue chip associated with a phosphor will see its performance reduced to 2-3 MHz. To overcome this problem, it is possible to filter the signal in blue before the photo detector in order to keep only the response of the chip.

Conventionally, the use of a blue filter not associated with a converging lens makes it possible to use 10% of the signal available before the filter. In the case of optical reception in an environment with high light intensity (sunlight in an outdoor environment for example), this characteristic can have a definite advantage in avoiding saturation of the photo detectors by wavelengths outside the VLC spectrum. or LiFi. The VLC or LiFi signal then goes from a useful signal / spectrum ratio in an external environment of 500 Lux / 150,000 Lux, to a ratio of 100 Lux / 20,000 Lux. Unmodulated light, for example from the sun, is no longer a reason for not detecting the LiFi signal because the saturation of the photo detectors is avoided.

However, not all photo detectors are suitable for this type of detection in high ambient light flux. However, some photovoltaic photo detectors, as described in the publication Specifies innovative semitransparent solar cell for indoor and outdoor LiFi applications (E. Bialic, L. Maret, and D. Ktnénas, Applied Optics, Vol. 54, N ° 27 , pp 8062-8269 (2015)) have characteristics allowing the detection of small light variations in an outdoor environment with high light intensity.

In the case of a multi-chip LED, each chip can be addressed independently of its neighbor, which means that the light amplitude from each chip can be modulated independently. Thus each chip generates a particular communication channel which can be processed independently. Such a communication system is advantageous in that most of the photo-detecting surfaces associated with an information processing system making it possible to analyze the variation in the amplitude of the received light signal and d '' deduce the transmitted signal, provided that each photo detector receives only the useful signal from a dedicated communication channel. One way to dedicate a photo detector to a narrow band transmission channel is to use a color filter associated with the color which contains the useful signal.

As the use of a filter for optical communication reduces the use of the available spectrum to around 10% of the total spectrum, 90% of the light energy is therefore unused.

The object of the invention aims to maximize the use of available light energy while allowing the best possible detection of the modulated light signal allowing optical communication.

PURPOSE OF THE INVENTION

The invention aims to optimize the use of the visible spectrum, IR and UV, in the context of optical communication. It relates to a device which aims to maximize the energy generated by photovoltaic cells while minimizing the saturation constraints of optical telecommunications receivers. In other words, the object of the invention is, on the one hand, to direct the part of the useful spectrum of the modulated light towards the optical reception areas of telecommunications, and on the other hand to let pass almost all of the energy. to the photovoltaic zones dedicated to the recovery of electrical energy.

OBJECTS OF THE INVENTION

In its basic principle, the invention relates to a photovoltaic and optical reception device allowing both the production of energy and the reception of an optical communication, composed of at least two parallel plates:

- A first plate partially transparent to sunlight comprising a face on which is disposed a plurality of photoactive zones forming photo detectors dedicated to the reception of modulated light coming from a modulated light source carrying information, said photoactive zones being intrinsically opaque and separated by transparency zones;

- a second plate comprising a substrate on which is disposed a plurality of photovoltaic cells dedicated to the production of photoelectric energy and comprising an opaque electrode;

- characterized in that the active faces of said photo-active zones are opposite the active zones of said photovoltaic cells.

In a particular embodiment of the invention, the photoactive zones dedicated to receiving modulated light are photo-active photovoltaic zones.

Advantageously, the photo-active photovoltaic zones dedicated to the reception of modulated light are arranged according to a network of parallel photovoltaic strips or according to any other network of patterns (circle, hexagon, etc.) allowing the transparency of the first to be controlled. face of the device according to the invention. Advantageously, the transparency rate of the first face is greater than 50% thus allowing the optimization of the energy production by the second face.

In another particular embodiment of the invention, the multitude of photovoltaic cells is covered with one or more filters or dichroic mirrors which have the property of letting through part of the visible spectrum, IR or UV, and of reflecting l other part of the visible spectrum, IR or UV. This embodiment is particularly advantageous in the case where the sunlight and the modulated light coming from a modulated light source carrying the information come from the same direction. In this particular case, the photoactive zones do not receive the modulated light along a direct path but according to a reflected path. The use of dichroic filters or mirrors then allows part of the modulated light to be redirected to the photoactive zones. Advantageously, their filtering function makes it possible to reduce the glare of the photoactive zones by redirecting only part of the optical spectrum. Advantageously, several filters or dichroic mirrors can be used in order to select the communication channels via the reflection spectral band during a multichannel optical communication using multi-LED sources, such as for example a RYGB LED composed of 4 LED chips of colors red, green, yellow and blue.

Advantageously, said dichroic filter or mirror is optically structured on the surface to disperse the reflected rays so as to favor the redirection of the reflected rays towards the photo-active zones and towards the transparency zones.

In another particular embodiment of the invention, the multitude of photovoltaic cells is a network of parallel photovoltaic strips or any other network of patterns (circle, hexagon, etc.) allowing the transparency of the second face of the device to be controlled. according to the invention. Advantageously, the integral device is semi-transparent.

The invention also relates to glazing, in particular for building, characterized in that it comprises a photovoltaic and optical reception device as described above.

DETAILED DESCRIPTION

The invention is now described in more detail using the description of Figures 1 to 4.

Figure 1 is a block diagram of the device when it is in a semi-transparent embodiment integrated into a window in the case where the sunlight and the light carrying information are on either side of the device.

Figure 2 is a block diagram of the device when integrated into a wall covering in the case where the sunlight and the light carrying information are on the same side of said covering.

Figure 3 is a block diagram of the device when it is in a semi-transparent embodiment integrated into a window in the case where the sunlight and the light carrying information are on the same side of the window .

Figure 4 is a block diagram of the device when it is in a semi-transparent embodiment integrated into a window in the case where the sunlight and the light carrying information are on the same side of the window and that the communication is of the multi-channel optical type.

FIG. 1 is a block diagram which represents a device for receiving visible or invisible optical communication (IR or UV) and for receiving photovoltaic energy in a semi-transparent embodiment. In its basic principle, the device is composed of at least two parallel flat plates (21,22). The internal side of the flat plate (21) faces the modulated light (2). The outer side of the flat plate (21) faces the sun. The internal side of the flat plate (21) is covered with a network of photoactive zones (31) forming photo detectors dedicated to the reception of a modulated light dedicated to optical communication in free space and comprising zones of transparency (61). Advantageously, the photoactive zones are photovoltaic. The inner side of the flat plate (22) faces the sunlight (1). The internal side of the flat plate (22) is covered with separate active photovoltaic zones (32) revealing zones of transparency (62).

In an embodiment not shown here, the plate (22) is associated with an opacifying device whose opacification command is controlled by the information contained in the modulated light (2) received by the optical sensors (31).

Figure 2 is a block diagram showing a receiving device for visible or invisible optical communication (IR or UV) and receiving photovoltaic energy. In its basic principle, the device is composed of at least two parallel flat plates (21,22). The internal side of the flat plate (21), which does not face the sun (1), is covered with a network of photoactive zones (31) forming photo detectors dedicated to receiving dedicated modulated light to optical communication in free space. The active areas of the photo detectors are arranged opposite the internal side of the flat plate (22), so as to receive only some of the rays reflected (121) by the surface (42). The surface (42) is a surface transparent to part of the visible spectrum which transmits this part of the spectrum to the photovoltaic surface (32) dedicated to the generation of electrical energy and which reflects a narrow band of the received optical spectrum (121, 122 ) to the photo-active areas (31) dedicated to optical communication.

Positioned as an exterior wall covering, the device thus optimizes the production of electrical energy generated by the photovoltaic cells (32) while optimally receiving (i.e. unsaturated by stray ambient light) the data. visible or invisible optical communications. Advantageously, the photoactive zones (31) could be photovoltaic elements arranged for example in a network of parallel bands (31) absorbing in the part of the spectrum of the modulated light.

In another embodiment not shown here, the two plates can be concave, convex, or have curvatures making it possible to improve the functional or aesthetic appearance of the device.

Figure 3 is a block diagram showing a receiving device for visible or invisible optical communication (IR or UV) and receiving photovoltaic energy in a semi-transparent embodiment. In its basic principle, the device is composed of at least two parallel flat plates (21,22). The internal side of the flat plate (21), which does not face the sun (1), is covered with a network of optical sensors dedicated to optical communication in free space. The active areas of the optical sensors are arranged opposite the internal side of the flat plate (22), so as to receive only some of the rays reflected (121) by surface portions (42). The surface (42) is a surface transparent to part of the visible spectrum which transmits this part of the spectrum to the photovoltaic surface (32) dedicated to the generation of electrical energy and which reflects a narrow band of the received optical spectrum (121, 122 ) to the optical sensors (31) dedicated to optical communication. The internal side of the plate (22) which faces the sun is covered with separate photovoltaic photo-active zones (32) associated with dichroic filters (42). Arranged so as to form windows, the device thus optimizes the production of electrical energy generated by the photovoltaic zones (32) while receiving in an optimal manner (that is to say unsaturated by the stray ambient light) the visible or invisible optical communications data while retaining the semi-transparency functionality.

In another embodiment, described by the diagram in FIG. 4, dichroic filters or mirrors with different reflection properties, can be distributed randomly or not over the photovoltaic zones dedicated to energy production, with the aim of selectively select spectral bands for multi-channel optical communication. The dichroic filters (421, 422, 423) can for example be dedicated to a particular modulated colored light (for example, red, green and blue respectively) coming from a multi-chip LED lamp (red, green and blue). Thus, the photo-active areas addressed separately will make it possible to recover information from the three optical communication channels simultaneously without multi-spectral interference.

In another embodiment, not shown here, the two plates (21, 22) can be concave, convex, or have curvatures making it possible to improve the functional aspect (sunroof of a car for example) or aesthetic of the device.

EXAMPLE OF IMPLEMENTATION

A concrete example of realization is composed of a rectangular double glazing in glass of 70cm x 100 cm and 4 mm thick. The first internal face of the double glazing is covered with a network of parallel photovoltaic strips with a width of 200 microns and spaced 20 mm apart. The second internal face of the double glazing is covered with a network in parallel photovoltaic strips with a width of 200 microns and spaced 1 mm apart. The active face of the photovoltaic surfaces of the second face is covered with a blue dichroic mirror which lets through all the colors of the visible spectrum except blue. The non-active face of the photovoltaic surfaces is composed of an electrically transparent conductive electrode. The active dichroic faces are therefore opposite the first internal face. The photovoltaic surfaces are electrically coupled partly in series mode and partly in parallel mode in order to obtain an output voltage of the device which is close to 24 volts.

This device corresponds to a photovoltaic glazing producing photovoltaic energy via its second face and to a glazing for receiving optical communication via its first face. Advantageously, this system works both when the modulated light comes from the same direction as the sun (by reception of the rays reflected by the dichroic mirror) and when it comes from an opposite direction. This type of glazing can therefore be integrated into buildings and can receive information from exterior and interior modulated luminaires.

Claims (7)

1 - Photovoltaic and optical reception device allowing both the production of energy and the reception of an optical communication, composed of at least two parallel plates (21,22): - a first plate (21) partly transparent to sunlight (1) comprising a face on which is arranged a plurality of photoactive zones (31) forming photo detectors dedicated to the reception of modulated light coming from 'a modulated light source (2) carrying information, said photoactive zones (31) being intrinsically opaque and separated by transparency zones (61); - a second plate (22) comprising a substrate on which is disposed a plurality of photovoltaic cells (32) dedicated to the production of photoelectric energy and comprising an opaque electrode; - characterized in that the active faces of said photoactive zones (31) are opposite the active zones of said photovoltaic cells (32). 2 - Device according to claim 1, characterized in that said photo-active areas (31) dedicated to the reception of modulated light are photo-active photovoltaic areas. 3 - Device according to any one of the preceding claims, characterized in that said photo-active areas (31) photovoltaic dedicated to the reception of modulated light (2) are arranged according to a network of parallel photovoltaic strips separated by areas transparency (61). 4 - Device according to claims 1 or 2, characterized in that said photo-active areas (31) photovoltaic are arranged in a network of circular or polygonal photovoltaic patterns. 5 - Device according to any one of the preceding claims, characterized in that the plurality of photovoltaic cells (32) is covered with a ¹⁰ or more filter or dichroic mirrors (42, 421, 422, 423) which have the property to let pass part of the visible spectrum, IR or UV and to reflect the other part of the visible spectrum, IR or UV. 5 6 - Device according to claim 5, characterized in that said filters or dichroic mirrors (42, 421, 422, 423) are optically structured on the surface to disperse the reflected rays (121, 122) so as to favor the redirection of the rays reflected towards the photoactive areas of the photo detectors (31). 7 - Device according to one of the preceding claims, characterized in that said substrate is transparent and in that the plurality of photovoltaic cells (32) is a network of parallel photovoltaic strips or any type of network of patterns for generating transparency zones (62). 8 8 - Glazing, characterized in that it comprises a device according to any one of claims 1 to 7. 1/3 --— --- sH i