FR3048054A1 - LIGHTING SYSTEM - Google Patents

Abstract

The present invention relates to a lighting system comprising at least one light-emitting diode providing light at defined wavelengths, said lighting system being provided with optical converters capable of converting a portion of the visible light emitted by the diode electroluminescent light source (1) in a different wavelength range, said converter preferably having an optically active material modifying the emission spectrum to increase, relative to the nominal spectrum of the light-emitting diode, the energy in the band between 530 and 590 nm, compared to the energy in the band below 530 nm, to reduce the attractiveness for insects.

Description

LIGHTING SYSTEM Field of the invention

The present invention relates to the field of lighting with light-emitting diodes and more particularly the reduction of the attraction of blood-sucking insects such as mosquitoes.

It is well known that artificial light attracts insects, including Aedes Agypti mosquitoes, which are recognized as "dangerous" because they carry disease such as Dengue fever, yellow fever, Chikungunya or Zika virus. Nighttime lighting in areas infested with blood-sucking insects poses great difficulties as users move closer to sources of light for their occupations, and thus find themselves in an area naturally attracting hematophagous insects attracted by light.

Solution of the prior art

To answer this problem, it has been proposed in the prior art different solutions.

A first solution described in US Pat. No. 7,835,631 combines a lamp and a volatile insect repellent dispensing device. Light is produced by light bulbs or light-emitting diodes (LEDs) while an insect repellent is delivered by heating a volatile insecticide. The insecticide and the portable lamp can be used either simultaneously or independently of each other.

A second type of solution is described in the international patent application WO2015035667 describing a mosquito trap. The mosquito trap includes an envelope, a lamp tube and a conductive coil both secured in the envelope. The lamp tube emits light and the conductive coil is electrically connected. Because of the phototaxis of the mosquito, the light emitted by the lamp tube attracts the mosquito, and the electrically connected conductive coil kills the mosquito directly by using a direct current when the conductive coil comes into contact with the mosquito.

Disadvantages of prior art

The solutions of the prior art are not satisfactory because they are content to treat the mosquitoes attracted by the light source, but not to reduce the attractiveness of the insects of the light source.

Solution provided by the invention

In order to remedy these drawbacks, the invention relates, in its most general sense, to a lighting system comprising at least one light-emitting diode providing light at defined wavelengths, said lighting system being provided with optical converters capable of converting a portion of the visible light emitted by the light-emitting diode into visible light in another wavelength range characterized in that said converter preferably comprises an optically active material modifying the emission spectrum to increase, relative to to the nominal spectrum of the light-emitting diode, the energy in the band between 530 and 590 nm, with respect to the energy in the band below 530 nm.

This solution reduces the attractiveness for insects and not only to treat insects attracted by the light source.

Advantageously, the light-emitting diode is encapsulated in a transparent material doped with at least one photoluminescent compound that converts the nominal emission spectrum of the diode to a spectrum that increases the light energy in the band between 530 and 590 nm.

According to one variant, the light-emitting diode is encapsulated in a transparent material coated by a band-pass filter in the range between 530 and 590 nm.

According to a particular embodiment, the light-emitting diode is associated with an optical lens having on at least one of its surfaces a dichroic coating.

Advantageously, said dichroic coating has a transmission curve of at least 95% in a spectral band between 530 and 590 nm.

Detailed Description of a Non-Limiting Example of the Invention

The present invention will be better understood on reading the detailed description of a nonlimiting example of the invention which follows, with reference to the appended drawings in which: FIG. 1 represents a schematic view of a first exemplary embodiment of a lighting system according to the invention - Figure 2 shows a schematic view of a second embodiment of a lighting system according to the invention - Figure 3 shows the light spectrum of the aforementioned lighting system - FIG. 4 represents a schematic view of a third exemplary embodiment of a lighting system according to the invention; FIG. 5 represents a schematic view of a fourth embodiment of a lighting system according to FIG. invention

FIG. 1 represents a first example of implementation of a lighting system according to the invention. It comprises an LED semiconductor component (1) associated with a metal thermoregulation support. The LED component (1) is connected to two electrical connection tabs (3, 4). This assembly is embedded in a base (5) of opaque plastic material having a cavity (6) filled with a transparent polymer (7) mixed with a phosphor layer to modify the spectral curve emitted by the component (1) so as to increase the light energy in the band between 530 and 590 nanometers. The increase of the light energy in this band can be obtained by phosphors absorbing a portion of the energy in the wavelengths lower than 530 nm and retransmitting at longer wavelengths, greater than 530 nm. The assembly is surmounted by a glued or overmolded lens, for example made of PMMA.

FIG. 2 represents an embodiment variant comprising a hemispherical transparent lens (9) having a dichroic coating.

The lighting system according to this example has a yield of 145 lm / W (or 2395 lm) at 500 mA. The LED component produces light with a color temperature of 4000K ± 200K.

The LED component (1) can be a Chip on Board (COB) type module, a mid-power LED assembly (without primary optics), or a set of high power LEDs on their printed circuit board (PCB) constituting a single unit. and even optical source. .

The module comprises a hemispherical lens (9) made of glass or polymer such as polycarbonate, poly (methyl methacrylate) (often abbreviated to PMMA) or polydimethylsiloxane, commonly known as PDMS or dimethicone (Poly (methyl methacrylate)). .

This lens (9) is shaped a dichroic passband coating with specific transmission between 530 nm and 590 nm. When an anti-reflective coating is added to the lens, the optical power loss between a dichroic coated lens with anti-reflective coating and the same lens without dichroic coating with anti-reflective coating is 2.4%.

The layer forming the dichroic coating may be formed by vacuum treatment by misting rare-metal oxide (titanium, chromium, aluminum, zirconium, magnesium or silicon).

The wavelength conversion effected by the dichroic coatings increases the share of optical power perceived by the eye relative to uncoated glass. Despite the overall loss of optical power demonstrated above, the luminous flux measured with coating is therefore greater than the luminous flux measured on the control glass. The variation in efficiency (in lm / W) as a function of the current therefore follows the following curves.

The spectra measured on the LED module with the different glasses tested are given in FIG. 3, representing for the curve (11) the spectrum in the absence of dichroic treatment, and in curve (12) with the dichroic treatment.

These spectra consist of a first blue peak at 450 nm which is that of the GaN semiconductor used for the LEDs, and two secondary peaks respectively at 535 nm and 595 nm, which represent the emission of the phosphor added to the encapsulant (6). These secondary peaks correspond to the absorption-reissue phenomenon operating through the encapsulant mixed with the phosphor when the latter is excited by the LED source emitting a central wavelength close to 450 nm.

The colorimetric performances measured on the coated glasses show a variation of color temperature compared to the control glass, which temperature goes from about 4800K to 4200K or 4300K depending on the case. This function is optional in the composition of the dichroic coating.

Additionally, the anti-reflection layer makes it possible to reduce the optical losses due to the total internal reflection that would operate without the presence of the latter.

The tests made it possible to compare the attraction of the lighting systems according to the invention to mosquitoes.

The tests were carried out using a bifurcated chamber (called by the skilled person "Y-maze"), each branch having a light source. Efficiency is estimated by measuring the number of branching mosquitoes according to the light source it contains, and also by the number of mosquitoes remaining in the branches after a certain time.

When one branch is lit by a halogen lamp and the other is placed in the dark, 66% of the mosquitoes move towards the branch lit by the halogen source.

When one branch is illuminated with a halogen source and the other with a system according to the invention, 80% of the mosquitoes move and stay towards the branch illuminated by the halogen source.

When one of the branches is obscured and the other with a system according to the invention, 62% of the mosquitoes move and stay towards the obscured branch.

The lighting source according to the invention is therefore less attractive to mosquitoes than dark, unlike usual lighting sources.

FIG. 4 shows an embodiment of a lighting system according to the invention constituted by an LED street lamp incorporating several LED modules in a sealed metal housing with a glass (15) on the front face. This glass (15) is treated, for example by a dichroic coating producing a bandpass filter in the range 530-590 nm. The glass (15) also has an anti-reflective coating.

FIG. 5 shows another variant of a lighting system formed by a printed circuit board (16) on which LED modules (18) are mounted. A molded optical lens (18) having a bandpass filter processing in the 530-590 nm range covers the LED modules (18).

Claims (5)

claims 1 - Lighting system comprising at least one light-emitting diode providing light at defined wavelengths, said lighting system being provided with optical converters capable of converting a part of the visible light emitted by the light-emitting diode (1 ) in visible light in another range of wavelengths characterized in that said converter preferably comprises an optically active material modifying the emission spectrum to increase, compared to the nominal spectrum of the light emitting diode, the energy in the band between 530 and 590 nm, compared to the energy in the band below 530 nm, to reduce the attractiveness for insects. 2 - lighting system according to claim 1 characterized in that the light emitting diode (1) is encapsulated in a transparent material doped with at least one photoluminescent compound ensuring a conversion of the nominal emission spectrum of the diode to a spectrum increasing l light energy in the band between 530 and 590 nm. 3 - lighting system according to claim 1 characterized in that the light emitting diode is encapsulated in a transparent material coated by a bandpass filter in the range between 530 and 590 nm. 4 - lighting system according to claim 1 characterized in that the light emitting diode is associated with an optical lens having on at least one of its surfaces a dichroic coating. 5 - Lighting system according to the preceding claim characterized in that said dichroic coating has a transmission curve of at least 95% in a spectral band between 530 and 590 nm.