WO2015007995A1

WO2015007995A1 - Illumination device

Info

Publication number: WO2015007995A1
Application number: PCT/FR2014/051835
Authority: WO
Inventors: Bilal HIJAZI; Julien Dubois; Frédéric Cointault; Jürgen VANGEYTE; Cédric CLERC
Original assignee: Universite De Bourgogne; Agrosup Dijon; Ilvo - Institute For Agricultural And Fisheries Research-Management
Priority date: 2013-07-17
Filing date: 2014-07-17
Publication date: 2015-01-22
Also published as: FR3008769A1; FR3008769B1

Abstract

The present invention belongs to the field of illumination devices. More particularly, the present invention concerns an illumination device that makes it possible to uniformly illuminate a large surface area with low power consumption. The present invention also concerns imaging techniques using the device according to the invention.

Description

LIGHTING DEVICE

Technical area

The present invention belongs to the field of lighting devices. More particularly, the present invention relates to a lighting device for uniformly illuminating a large area with low power consumption. The present invention also relates to imaging techniques using the device according to the invention.

Prior art

Imaging techniques make it possible to offer a large number of solutions in the field of metrology and instrumentation for non-intrusive measurements. These methods inevitably require a lighting device adapted to the acquisition system. Proper illumination of a scene effectively involves a lighting system providing high light intensity, high robustness, low cost and strong portability.

For example, these lighting devices are used to analyze the spreading of fertilizer in particular by centrifugal systems and more particularly in order to establish a typology of the products (behavior, resistance to friction, characteristics of erection ...), to study the influence of the type of centrifugal spreader used, and finally to develop a fertilizer spreader.

The first tests carried out by the applicant, in order to better manage the distribution of fertilizers by centrifugal spreading, led him to consider the use of very intense light sources. As an indication, he showed that 4 spots of 200W each provide the required light intensity of 5,000 lux in the plane of the spreading disc, at a distance of 20 cm from the luxmeter used, which represents an intensity of 1,000 lux at a distance of 1 meter.

In order to reduce the cost of an illumination system and increase its robustness, the present invention provides an alternative lighting solution. This solution is also more portable, more compact and more suitable for installation closer to an acquisition system.

Summary of the invention

Thus, the present invention relates to a lighting device comprising LEDs remarkable in that said LEDs are arranged on a path in the form of a hexagon.

In the context of the present invention, the term "LED" is intended to denote light-emitting diodes and advantageously power LEDs.

In the context of the present invention, the term "disposed" means that said LEDs are all placed in the same plane and oriented in a direction perpendicular to said plane.

According to a preferred embodiment of the invention, said LEDs are arranged at the vertices of said hexagon.

According to a preferred embodiment of the invention, said hexagon is a regular hexagon.

According to a preferred embodiment of the invention, said LEDs are arranged at the vertices of several regular hexagons sharing the same centroid.

According to a preferred embodiment of the invention, said LEDs are arranged at the vertices of a first and a second regular hexagon sharing the same barycentre, whose sides have the same length and whose first hexagon is the image by rotation of 30 ° around said center of said second hexagon.

According to a preferred embodiment of the invention, said device further comprises at least 6 LEDs arranged at the vertices of a third regular hexagon center of barycentre identical to the center of said first and second hexagon and whose side of said first hexagon is twice longer than the side of the third hex.

According to an even more preferred embodiment of the invention, the sides of said third hexagon are parallel to the sides of said first or second hexagon.

According to an even more preferred embodiment of the invention, said device comprises at least 4 140 ° opening LEDs at the vertices of each of said first and second hexes and at least 2 80 ° opening LEDs at the vertices of said third hexagon.

According to an even more preferred embodiment of the invention, said device further comprises at least 4 LEDs arranged at the vertices of a square of barycentre identical to the barycentres of said hexagons, with substantially equivalent sides or two sides of said hexagons, and each of which side is parallel to at least one side of said first and second hexes.

According to a preferred embodiment of the invention, said device comprises several LEDs at the vertices of said hexagons.

According to an even more preferred embodiment of the invention, the device comprises 3 LEDs arranged at each of said vertices, said 3 LEDs are arranged in the form of an equilateral triangle.

According to a most preferred embodiment of the invention, said lighting device comprises only, as a light source, the LEDs disclosed in the embodiments described above.

Thus, according to a particularly preferred embodiment, said lighting device comprises only, as a light source, LEDs arranged at the vertices of several regular hexagons sharing the same centroid.

The lighting device according to the invention makes it possible to minimize the number of LEDs used and thus to minimize the financial cost of the system and the cost of use by limiting the electrical power consumed. It also makes it possible to provide uniform illumination ranges much wider than the prior art lighting devices (> lm ² ). Finally, the lighting devices according to the invention make it possible to propose a stroboscopic mode at high speeds (> 1 MHz).

Brief description of the drawings

Figure 1 is a schematic description of an embodiment of a lighting device according to the invention.

FIG. 2 is a graph showing the distribution of the lighting obtained thanks to the device presented in FIG.

Figure 3 is a schematic description of an embodiment of a lighting device according to the invention.

FIG. 4 is a graph showing the distribution of the lighting obtained thanks to the device presented in FIG.

Figure 5 is a schematic description of an embodiment of a lighting device according to the invention. FIG. 6 is a graph showing the distribution of the lighting obtained thanks to the device presented in FIG.

Description of the embodiments

The systems described below are lighting devices according to the invention used statically and / or dynamically, making it possible to obtain wide ranges of uniform illumination and having the following characteristics:

A spatial distribution made from geometric shapes, in particular hexagons. The top of each form consists of 1 to N

LEDs (depending on the size and luminous power desired for the application).

Each LED can have its own characteristics (opening angle, light output, color temperature). Each LED can be controlled individually, thereby controlling the light intensity, energy consumption and color temperature of said device.

The device according to the invention can be used on the one hand independently and remotely with respect to an image acquisition system and / or videos, and / or associated with these. In this case, the imaging system can then be located in the center of the lighting device according to the invention.

Below are presented three preferred lighting devices according to the invention.

The first lighting device shown in Figure 1 provides an intensity of 1,000 lux on a surface square of lmxlm. The device implements a set of 48 LEDs distributed in a hexagonal geometric arrangement.

The luminous intensity obtained is relative to the number of LEDs used, their characteristics (power, opening) and the height at which they are located relative to the scene. On each of the vertices of the hexagon, the LEDs are preferably associated in the form of a triangle to make the illumination optimal as shown in FIG.

The second lighting device represented in FIG. 3 associates several concentric hexagons hexagons, composed of LEDs of different openings:

On the central hexagon, 4 LEDs per vertex with an opening of 140 °,

On both peripheral hexes, 2 LEDs per vertex with an 80 ° aperture.

The luminous power achieved with the distribution of the LEDs according to this embodiment is shown in FIG. 4.

The third lighting device shown in FIG. 6 still makes it possible to improve the homogeneity of the lighting, the hexagonal shapes of the preceding devices have been coupled with a square shape, giving the final configuration of FIG. 5. In this case here, homogeneity is obtained over an area of 120 x 120 cm ² .

The lighting device according to the invention can notably be used as an LED stroboscope with a wide uniform lighting range, for building lighting and especially for the development of facades of historic buildings and for the lighting of buildings. interior of museums.

The lighting devices according to the invention can also be used in the agronomic and / or agro-food field. Advantageously, said devices in the field of precision spraying for the visualization of crop protection impacts, in precision horticulture for the choice of the best spray nozzles and as a lighting tool at lower cost and lower consumption on agricultural machinery.

Claims

1. A lighting device characterized in that it comprises only, as light source, LEDs arranged at the vertices of several regular hexagons sharing the same barycentre.

2. Lighting device according to the preceding claim characterized in that said LEDs are arranged in the same plane.

3. Device according to one of the preceding claims characterized in that said LEDs are arranged at the vertices of a first and a second regular hexagons sharing the same barycentre, whose sides have the same length and whose first hexagon is the same. image by rotation around said center of gravity and 30 ° angle of the second hexagon.

4. Device according to the preceding claim characterized in that it further comprises at least 6 LEDs arranged at the vertices of a third regular hexagon center of barycentre identical to the center of said first and second hexagon and whose side of said first hex is twice longer than the side of the third hex.

5. Device according to the preceding claim characterized in that the sides of said third hexagon are parallel to the sides of said first or second hexagons.

6. Device according to claim 4 or 5 characterized in that it comprises at least 4 LEDs opening 140 ° to the vertices of each of said first and second hex and at least 2 80 ° aperture LEDs at the vertices of said third hex.

7. Device according to one of claims 4 to 6 characterized in that it further comprises at least 4 LEDs arranged at the vertices of a barycentre square identical to the barycentres of said hexagons, substantially equivalent sides or double sides of said hexagons , and each side of which is parallel to at least one side of said first and second hexes.

8. Device according to one of claims 1 to 7 characterized in that it comprises several LEDs at the vertices of said hexagons.

9. Device according to the preceding claim characterized in that it comprises 3 LEDs arranged at each of said vertices and in that said 3 LEDs are arranged in the form of an equilateral triangle.