WO2007093023A1 - A process of varnishing a lens and a reflector of an illumination component, an illumination component and a vehicle - Google Patents

Abstract

One describes a process of varnishing a lens and a reflector of an illumination component, particularly an illumination component (1 ) such as an automobile headlight or lamp comprising a first step of applying at least one varnish component to at least one surface of at least one lens (2) and/or at least one surface of at least one reflector (3), and at least one second step of curing the varnish, the second step comprising the application of electromagnetic waves produced by at lest one light emitting diode (11 ). One describes also an illumination component (1 ), such as an automobile headlight or lamp, and a vehicle.

Description

Specification of the Patent of Invention for: "A PROCESS OF VARNISHING A LENS AND A REFLECTOR OF AN ILLUMINATION COMPONENT, AN ILLUMINATION COMPONENT AND A VEHICLE".

The present invention relates to a process of varnishing a lens and a reflector of an illumination component, particularly a component for use on vehicles, such as an automotive headlights or lamps. The invention further relates to an illumination component, the components of which, such as lens and reflector, have been varnished according to the presently claimed the process and still to a vehicle equipped with at least one said illumination component.

Description of the Prior art

Almost all vehicles, be they automotive or not, have illumination components, such as headlights and lamps, which are indispensable for the driver to signal his attitudes (braking, changing roadway, signaling turns, en- gaging a reverse gear, etc.), as well as to see and be seen in the traffic, enabling daily and night traffic in safety.

In order for said illumination components to meet the practical, technical and legal requirements, they have to satisfy a number of specific technical rules and legislations, which aim at providing parameters for their functioning so as to maximize and/or normalize their performance and actuation.

Among the main technical parameters that an illumination component has to meet, we can cite the resistance of the lenses, the illumination capacity and their resistance to scratches and abrasions, the latter being very important, so that the illumination component will not become useless after a short time of use.

The illumination capacity, particularly in the case of a headlight of a vehicle, is measured as a function of a number of related technical parameters, so that the beam of light emitted by it will have good values of depth and luminosity, without blinding the driver who travels in the opposite direction.

Additionally, the headlights and lamps are elements more and more undissociable from the style of vehicles, aiding to compose them in their integrity, so that these illumination components can be designed by taking into consideration the design too, as a prime aspect.

It is a fact that headlights and lamps are more and more directly lined to the esthetics of the vehicle, often being some of its most prominent and outstanding elements. So much so that numberless car assembling companies seek to provide the vehicles of their lines with headlights and/or lamps of similar appearance, thus trying to create a visual identity among all of them (family feeling). At present, by the way, the statistic trend dictates the existence of headlights having a raised area, occupying a considerable part of the front of the vehicle, and for this reason their appearance and finish have a vital importance in the composition of the final style/design.

Specifically with regard to the headlights, the technological development observed in the last few years has been appreciable. During many years, these headlights were constituted by a housing of a metallic or plastic material, a smooth internal mirror-polished reflector with means for attaching at least one lamp or a corrugated glass lens, which enclosed the reflector in the housing. The lens corrugations, arranged on its internal surface, enabled one to direct correctly the beams of light emitted by the lamp, since this task was not performed satisfactorily by the smooth reflector, because it reflected light, without much accuracy.

However, the technical and market requirements as far as the illumination capacity and the design of the headlights were making clear some of the disadvantages intrinsic in this type of construction, as for instance (i) the limited illumination capacity provided thereby, due to the lens corruga- tions, which upon directing the beams of light emitted by the lamp, did not manage to take advantage of the whole illumination capacity of the lamp, (ii) high weight and the low resistance to impact of the glass lenses, which sometimes caused the headlight to become useless in the event of minor impacts. With a view to eliminate some of the drawbacks mentioned above, the manufacturers of headlights developed lenses made of transparent polycarbonate and reflectors provided with the complex surface technology, which immediately solved all the problems inherent in the use of glass. In this type of headlight, the lens is smooth because all the rays of light emitted by the lamp are correctly directed by the reflector. For this purpose, the reflector has a mirror-polished surface that seems to be smooth, but in reality has previously calculated rugosity, so that each ray of light that falls onto it will be correctly directed through the lens. Due to the performance of the reflector, the only function of the lens will be that of a transparent covering, preventing the entry of dirt and moisture into the headlight.

However, other drawbacks have emerged, which are the low re- sistance to abrasion of this polymeric material and the great formation of vapor inside the polycarbonate lens, which were overcome at least satisfactorily by application of varnishes/special films.

With the technological advance, one began to apply the complex surface technology to the taillights and to varnish the lenses thereof. The presently known processes of varnishing reflectors and headlight lenses and lamps have the same essential characteristics and are carried out by physicochemical reactions of the components of the varnish when activated by external agents such as, for example, ultraviolet (UV) radiation. The option of varnishing by ultraviolet radiation is justified by the qua- litative and productive performance provided in comparison with other external agents, such as high temperature (when thermal or hybrid varnishes are used).

The ultraviolet radiation is an electromagnetic radiation, such as visible light, but it has a shorter wavelength, which makes it invisible to the human eye. By varying the wavelength one can obtain invisible infrared, visible light (from red to violet), visible ultraviolet (UV), microwaves, etc.

At present the ultraviolet radiation necessary for activating the varnishes applied to headlight lenses and reflectors is obtained from a system of microwave lamps or arc lamps. Both systems have a high consumpti- on of energy, a relatively short life time and a considerable high investment value, which makes the present-day processes of varnishing extremely sophisticated and expensive. These characteristics of high acquisition and operational cost limit the use of the UV-vamishing process in the automotive branch to the competition of large or multinational companies, and the headlights and lamps produced have a higher aggregate value in performance and esthetics and also a higher manufacturing cost.

There are still UV-vanishing processes with microwave or arc systems that are used in the branches of wood, optics, electronic components, graphic and digital media. However, in these branches too the use of the cited processes is limited by the financial questions commented above. Another inefficiency of the present-day UV-varnishing systems, which a broad light spectrum is generated, ranging from infrared wavelength to deep ultraviolet (U.V.C.) and, also as an unavoidable product of the functioning of lamps, a large amount of heat is dissipated.

An electric power source feeds and controls two magnetrons (wave emitters), which emit electromagnetic waves at the microwave wavelengths. The microwaves fall onto the quartz bulb (simply called bulb or lamp) containing mercury (Hg). When irradiated by the microwaves, mercury generates a wave spectrum that ranges from 200 nm (nanometers) (in the ultraviolet light region) to 600 nm (in the visible light region). The efficiency of this system is low, because 10 KW (kilowatts) of electric energy is necessary to generate 6,000 W (watts) of irradiated power, that is to say, 40% of this applied energy simply does not result in irradiation. In addition, only about 10% of the 6,000 W (600 W) are used for carrying out the curing of the varnish. Therefore, the degree of energetic efficiency of this process is so low that only about 10% of this energy (between 500 W and 1 ,000 W) is used, the remainder being converted mainly into thermal energy in the form of infrared rays.

This low efficiency is due mainly to the fact that two conversions of energy (electricity into microwaves and then microwaves into ultraviolet light) are carried out and a very broad spectrum is generated, which ranges from infrared to deep ultraviolet (UVC).

A last disadvantage of this type of process is the presence of mercury (hg) and other secondary compounds in the lamps, which are very toxic and have a high capacity of contaminating the environment when their useful life comes to and end, which is of about 6,000 hours, a considerably reduced period. Until now, therefore, no varnishing process had been developed for use on lenses or reflectors of illumination components that did not exhibit all the drawbacks mentioned above. Objectives of the invention

An objective of the present invention is to provide a process of varnishing lens and reflector of an illumination component, particularly a lens or reflector made from a polymeric material, which brings about efficiency in applying varnish and a reduced implantation and operation costs, enabling the illumination components to exhibit high quality, an optimum performance/functioning and a competitive manufacture cost. Another objective of the present invention is to provide an illumination component, the lens and/or reflector of which is varnished by the process mentioned above and, finally, a vehicle provided with at least one such illumination component. Brief description of the invention The objectives of the present invention are achieved by means of a process of varnishing lens and reflector of an illumination component, particularly an illumination component such as a headlight or lamp for use on vehicles, comprising at least a first step of applying at least one varnish component to at least one surface of at least one lens and/or at least one surface of at least one reflector, and at least one second step of varnish curing, wherein the second step comprises applying electromagnetic waves produced by at least one light emitting diode.

The objectives of the present invention are also achieved by means of an illumination component, particularly an illumination component su- ch as a headlight or lamp for use on vehicles, comprising at least one lens and/or at least one reflector that comprise at least one surface each, these surfaces being varnished according to the process defined in the preceding paragraph.

Further, the objectives of the present invention are achieved by means of a vehicle that comprises at least one illumination component such as defined in the preceding paragraph. Brief description of the drawings

The present invention will now be described in greater detail with reference to embodiments represented in the drawings. The figures show:

- Figure 1 is a schematic sectional view of an illumination component, in this case a headlight of a vehicle; - Figure 2 is a schematic view of the UV-ray generating device, used in the varnishing process of the present invention;

- Figure 3 is a schematic view of the use of UV rays in varnishing a lens of an illumination component according to the process of the present invention; - Figure 4 is a schematic view of the use of UV rays in varnishing a reflector of an illumination component according to the process of the present invention;

- Figure 5 is a first schematic graph of the wavelength emitted by a microwave lamp used at present; - Figure 6 is a second schematic graph of the wavelength emitted by the LEDs in the varnishing process of the present invention. Detailed description of the figures

The process of varnishing lens and reflector of an illumination component 1 of the present invention is innovatory and has a number of ad- vantages in comparison with the known and commented prior-art process.

Figure 1 illustrates schematically a generic illumination component 1 (in this case, a headlight of a vehicle), comprising a housing 4, to which a lens 2 is associated, enclosing a mirror-polished reflector 3.

The housing 4 and the lens 2 delimit the inside of the component 1 , in which one provides at least one lamp (not shown) and, by preference, at least one mirror-polished reflector 3. Preferably, but not compulsorily, the reflector 3 utilizes a complex surface technology, that it to say, its apparently smooth surface actually has tiny rugosities previously calculated, so that each ray of light coming from the lamp and falling onto it will be correctly directed to pass through the lens 2.

One can foresee a component 1 with one or more reflectors 3 and one of more lamps, for example, a headlight having, on the same piece, a first reflector for high beam (containing a respective lamp), a second reflector for low headlight (also containing its respective lamp), a third reflector for long-reach headlight (usually called in Portuguese "farol de milha") and a fourth reflector for the directional lamp. Therefore, the number of reflectors 3 and of lamps used is not a factor that limits the protection scope of this invention.

Thus, one can conceive a component 1 in which the inner surface itself of the housing 4 is produce so as to serve as a reflector 3, and the latter, as an autonomous piece, will not be provided. In this case, the reflector would be a portion of the housing.

The housing 4 is preferably made of a polymeric material, such as modified polypropylene with addition of talc or fiberglass, or any other necessary or desirable material.

Preferably, the lens 2 is transparent and made from transparent polycarbonate without coloration, even though it may have coloration in another substantially transparent polymeric material that is necessary or desirable.

Evidently, both the lens 2 and the reflector 3, and the housing 4 may assume any necessary or desirable shape. In essence, the process of manufacturing an illumination component 1 provided with lens and reflector made from polymeric materials, as for example, an automotive headlight or lamp or any other, comprises the essential steps of: manufacturing the elements (lens 2, reflector 3, housing 4, etc.), treating the lenses 2 and reflectors 3 by applying varnishes (varnishing pro- cess), with a view to optimize their properties and, finally, assembling the component 1 by joining lens 2, reflector and other components.

The varnishing process of the present invention, in addition to comprising the varnishing step proper and the curing of the varnish by using LEDs that generate electromagnetic waves in the ultraviolet range, which is exactly the innovation of the present invention, further comprises an intermediate step that precedes the curing, in which the varnish and the len- ses/reflectors, 2,3 are heated, which creates the ideal conditions for the curing to be carried out.

The curing of the varnish exists, since, as a general rule, the varnishes used contain components called photo-initiators. Upon receiving electromagnetic waves having a wavelength in the ultraviolet range, these com- ponents function as catalysts, initiating a physicochemical reaction called polymerization. The monomers (another varnish component) cluster, forming long chains called oligomers. After the curing, the varnishes exhibit the characteristics that justify their use on lenses and reflectors of automobile headlights and lamps, namely, high hardness to prevent scratches on the lenses and high brightness in the case of the reflectors 3.

Radiation in the wavelength of visible light does not cause the polymerization physicochemical reaction, for which reason its incidence is absolutely harmless for varnish curing.

As mentioned before, the headlights and lamps 1 of a more re- cent design have, as a rule, lenses 2 made from a transparent polycarbonate and reflectors 3 provided with complex surface technology, which has considerably increased the illumination capacity. In this type of component, the lens 2 is smooth because all the light rays emitted by the lamp are correctly directed by the reflector 3. For this purpose the reflector 3 has a mirror- polished surface that seems to be smooth, but in reality has rugosities previously calculated so that each ray of light falling onto it will be correctly directed through the lens. Due to the performance of the reflector 3, the only function of the lens 2 will then be that of a transparent covering, preventing the entry of dirt and moisture into the headlight/lamp 1. Also as already mentioned before, the varnishing began to be used because the lenses 2 made from a transparent polycarbonate exhibit insufficient properties of resistance to mechanical abrasion and resistance to exposure to sunlight. The lenses being vanished, they will then resist adequately to scratches from abrasion, from yellowing due to prolonged exposure to the sun's rays and also from preventing condensation of moisture inside the component 1 , which causes an undesired appearance. More recently, the reflectors 3 have not been manufactured from metal, but rather from a polymeric material, and varnishing are now being utilized in order to provide the reflector 3 with greater aluminum adherence during the manufacture process, conferring high brightness to the piece and protection against yellowing resulting from prolonged exposure to the sun's rays.

As a main innovation of the varnishing process of the present invention, one replaces the microwave or arc lamps already described with a set of UV-light emitting diodes, which are schematically illustrated in figure 2 with reference number 11. These light emitting diodes are usually called LEDs and emit ultraviolet rays in the spectrum that is most interesting for carrying out the varnishing.

This results from the fact that the conventional microwave lamps used today emit electromagnetic waves in a very broad spectrum, which ranges from 200 nm (ultraviolet region - U.V.C.) to 600 nm (visible light region, as can be seen in figure 5, and dissipate heat in the form of infrared.

Since only the emission of waves in the ultraviolet region (UV) is interesting, if the emission of waves in the other ranges, on the one hand, is harmless for the cure of the varnish applied to the lenses 2 and reflectors 3, on the other hand it brings an undesirable and absolutely unnecessary con- sumption of electric energy.

On the other hand, the use of LEDs brings about an extremely significant reduction in the consumption of energy, since they emit electromagnetic waves directly from the electric power fed in a narrow spectrum in the ultraviolet region, as can be seen in figure 6. On can see clearly that the- re is virtually no emission of electromagnetic waves with a frequency lower than 330 nm and higher than 400 nm, this emission being therefore focused on the most interesting and efficient region of the spectrum. It is still neces- sary to compare figures 5 and 6, so that one can perceive the narrower spectrum of wave emission by the LEDs 11 , only in the range of interest, that of UV rays.

It is evident, however, that the narrow spectral range of emission of the UV LEDs 11 may be displaced, reduced, increased modified in other manners depending on the need of each varnish, provided that they will chiefly emit electromagnetic waves in the ultraviolet range (from 200 nm to 400 nm).

By preference, one provides at least one ventilator or cooler 12or at least one heat exchanger with at least one fluid for cooling the LEDs.

All of this without mentioning that, unlike the microwave lamps used, the electricity is directly converted by the LEDs into electromagnetic waves, generating an energetic efficiency of about 90% (versus about 10% of the microwave lamps, as commented before). There is no significant loss of energy by generation of heat or generation of waves having lengths that are useless for application.

Thus, considering that the potency required for curing the varnish applied to the lenses and reflectors 3 is of about 500 W to 1 ,000 W (let us consider 1 ,000 W for the purpose of calculation), it follows that the electric potency consumed by the LEDs 11 is of about 1 ,100 W. On the other hand, with conventional microwave lamps, as mentioned before, the potency used for this purpose is of about 10 KW, that is to say, approximately 10 times as high. Only this saving of energy is already sufficient to have an idea of the improvement represented by the presently defined and claimed varnishing process.

In this way, in addition to the saving of electric power, one can reduce the auxiliary cooling systems used and the number of lenses/reflectors 2, 3 that become defective due to excess heat.

Another advantage is the useful life of the LEDs, which is much longer in comparison with microwave lamps (about 50,000 hours versus a- bout 6,000). So, there is a saving in maintenance costs, increasing the productivity (by virtue of the decrease in the number of interventions due to their useful life coming to and end) and decrease in the stock of spare parts.

Another considerable advantage of the LEDs and their power feeding systems is that they are much more simple and more compact that the present-day microwave lamp systems. In this way, one achieves a reduc- tion in the times and maintenance costs, loss of hours due to stoppage, more compact machines and less investments for implantation and expansion of the varnishing process.

It should be further noted that microwave lamps comprise mercury (Hg) and other toxic materials inside them, which is a serious drawback after the end of their reduced useful life, when these harmful elements, which are environmental passives, have to be discarded correctly allocated, at the risk of polluting the environment and of causing risks to people exposed thereto.

Another novel and innovatory invention is an illumination compo- nent, particularly an illumination component 1 such as a headlight or lamp for use on vehicles, comprising at least one lens 2 and/or at least one reflector 3, which comprise at least one surface each, these surfaces being varnished according to the presently claimed process.

And, finally, a novel and inventive innovative invention is a vehi- cle that comprises at least one illumination component as presently defined.

A preferred embodiment having been described, it should be understood that the scope of the present invention embraces other possible variations, being limited only by the contents of the accompanying claims, which include the possible equivalents.

Claims

1. A process of varnishing a lens and a reflector of an illumination component, particularly an illumination component (1) such as an automobile headlight of lamp comprising at least a first step of applying at least one var- nish component to at least one surface of at least one lens (2) and/or at least one surface of at least one reflector (3), and at least one second step of curing the varnish, characterized in that the second step comprises applying electromagnetic waves produced by at least one light emitting diode (11).

2. A process according to claim 1, characterized in that said light emitting diode emits electromagnetic waves in the ultraviolet (UV) wavelength, substantially between 330 nm to 400 nm.

3. A process according to claim 1 or 2, characterized in that the second step comprises heating the varnish and the lens and/or reflector (2,3) prior to application of the electromagnetic waves.

4. A process according to any of claims 1 to 3, characterized in that the light emitting diode emits electromagnetic waves with an energetic efficiency of about 90%.

5. An illumination component, particularly an illumination component (1) such as an automotive headlight or lamp comprising at least one lens (2) and/or at least one reflector (3), characterized in that the lens (2) and/or the reflector (3) comprise at least one surface each, these surfaces being varnished according to the process defined in claims 1 to 4.

6. An illumination component according to claim 5, characterized in that the lens (2) is constituted by polycarbonate.

7. An illumination component according to claim 5 to 6, characterized in that the reflector (3) is polymeric.

8. A vehicle, characterized by comprising at least one illumination component as defined in claims 5 to 7.