1 Title of the invention Device for emitting pulsed infrared radiation Background of the invention This invention pertains to the general domain of devices for emitting pulse infrared radiation, emitting reproducible impulses in the [91m, 10im] spectral range. Such an infrared emission Is destined for use in devices that measure the absorption by ethanol of infrareds located in the said range. Generally, such measuring devices based on infrared absorption use a pyroelectric detector which can only work in combination with a pulsed infrared emission. These devices thus generally use a continuousinfrared source associated with a rotating element allowing to periodically mask this source in order to generate a periodically reproducible alternative signal. Such a rotating element is commonlyknown as a "chopper". The use of such a rotating element requires the implementation of a motor capable of providing a constant and regular rotation movement, in a way that ensures the reproducibility of the infrared radiation impulses. Incidentally, it is known that it is difficult to produce reproducible impulses in the field of infrared wavelengths by operating an electronic component in an alternative manner. In fact, evolutionary thermal behaviour relating to the function of all electronic components is inevitably noted and renders the reproducibility of a pulsed infrared emission difficult to obtain, Goal and summary of the invention The primary goal of this invention is thus to level out the inconveniences of prior art, by proposing a pulsed infrared radiation 2 delivery device reproducible in the [9pm, 10pm] spectral range for use in a breathalyzer device composed of a measuring tank in which absorbance measurements are performed, characterized by at least one ballast capable of providing a pulsed current that is reproducible to a desired pulse frequency and a delivery module consisting of a substrate plane upon which a heating element made up of conductor material is placed, the heating element being coated with a layer capable of diffusing heat upon which a thin layer of at least one semi-conductive material is placed, the heating element being fed with the pulsed current provided by the ballast. Appropriately, in the intended effect of the breathalyzers, the desired pulse frequency is between 3 and 10 Hz for the needs of the sender/receiver combination. It was discovered by the inventors that, in a surprising manner, the modules that have a heating element consisting of a conductive layer or filament serving a heat reistor between a substrate and a thin layer of a semi-conductive material, this semi-conductive layer being isolated from the conductive layer by a heat diffusing layer, emits infrared radiation impulses that are completely reproducible in the set spectral range when the conductive layer is fed by a pulsed current at the desired pulsation frequency. However, it must be noted that such delivery modules, operating on the principal of caloric radiation delivery, generate isotropic radiation on the upper half-space of the delivery module. In particular, a component presenting the constitution of a delivery module such as defined in the invention is advantageously a semi-conductor reducing gas sensor using a variety of conductivity of the semi-conductive material in relation to the absorbing of gas on this material. According to this particularly advantageous implementation of the invention, such a component is deterred from the primary function for which it was conceived. Upon first use, such a sensor undergoes a chemical reaction on the sensitive layer which makes its electric conductivity vary. This 3 sensitive layer is heated at high temperature thanks to the conductor filament. The utilization of such a sensor in another implementation consists, no longer in watching the tensions in the sensitive layer connectors, to feed only the conductive filament so that the delivery device emits an infrared radiation. This is a totally new and original utilization of the gas sensor presenting the characteristics provided above. In particular, we know that these components emit a sensitively isotropic infrared radiation in a half-space generating a loss of energy in the case where a canalization of energy is desired. According to an advantageous characteristic, the output module is equipped with an emitter cone whose surface reflects the infrareds and whose angular opening allows for an improved transmission of infrared energy in a tubular measurement tank in which the absorption of infrareds is measured as is 10 the establishment of a majority of optical paths of superior length to those of the tubular measurement tank. This characteristic gives the output characteristic of the output module, as defined according to its invention, an angular selectivity. The presence of the emitter cone avoids, in turn, loss of radiation on the output module side. In the absence of such a cone, these lateral radiations disappear and are not effective in the delivery of infrareds which must be emitted in a reduced angular opening around an optical axis perpendicular to the surface of the output module, According to this characteristic, the emitter cone is particularly adapted to an improved transmission of energy in a tubular measurement tank, in which infrared absorption is measured. The presence of an emitter cone allows, moreover, to recuperate the rays that make varied angles with the optical axis of the output module, promoting the establishment of a majority of optical paths for infrared radiation, these optical paths being, by reflection on the surface of the emitter cone, then in the tubular measurement tank, of superior - indeed, 4 very superior - length, to that of the measurement tank. This is important to multiply the length and number of optical paths because it is an absorption measure. True, the utilization of a pulsed reproducible Infrared radiation delivery device according to the invention is destined for the manufacturing of infrared absorption measurement devices. This pulsed delivery device is thus coupled with a pyroelectric detector which can only detect the quality of infrared radiation when this radiation is pulsed. This thus requires that the radiation, such as received by the pyroelectric element, has crossed a sufficiently significant length in the absorber fluid so that the absorption measure may be specified enough for the requirements of the concerned measurement device. The presence of an emitter cone allows for the reinforcement of the quality of energy emitted in the angular opening which corresponds to that of the cone, and thus to reinforce the quality of energy sent into the measurement tank, The presence of the cone allows, moreover, that a sufficient quantity of optical paths of sufficient length be reached In the measurement tank in order to ensure sufficient quantitative absorption so that the measure be reliable and sufficiently resolved. According to an advantageous realization, the angular opening of the emitter cone is between 10" and 450. Preferentially, the angular opening Is between 350 and 4 0 4. Ideally, the angle is roughly 380. Such an angular opening corresponds classically to a compromise between the possibility of reflecting the rays and minimizing the losses by absorption by the material that makes up the emitter cone. It must also be noted that the output module may be created in a number of different ways and with different materials. Notably, the conductor layer or filament may be created in a metal chosen from among platinum, gold, silver or copper, or even created in doped polysilicon. These characteristics enable a number of fabrications at varied costs of the output module such as put into action according to the invention.
5 It must be noted, however, that the utilization of platinum allows for a very good control of impulses, energy thus being transferred in a way that is completely satisfactory towards the neighbouring elements of the conductive layer and allowing a very good reproducibility of the infrared radiation impulses obtained.The thin semi-conductive layer, also known as the sensitive layer, isadvantageously created using metallic oxide. Among these oxides are, in particular, tin oxide, aluminum oxide, tungsten oxide, silicon oxide and niobium oxide. In particular, the association of a platinum wire with a thin semi conductive tin oxide layer allows for obtaining an output module which emits reproducible impulses, when this write is fed with a period pulsed current, Advantageously, the metallic oxide is doped. This does not have a real impact on the thermal behaviour and thus the infrared radiation of the output module. However, the metallic oxide doping may respond to other requirements of the output module, thus being able to serve to other implementations, In the creation of the invention, the substrate may be created with a material chosen from among the silicon-based ceramics or substrates. Such substrates used communally in the field of semi-conductors, allows for a reproducible source of pulsed infrared to be obtained. According to an advantageous characteristic, a limiting membrane of thermal diffusion is inserted between the substrate of the conductive layer. This characteristic improves even more the thermal behaviour of the component by stabilizing the thermal phenomenon, Advantageously, the length of the tank is chosen in such a way that one can obtain the absorption measures while respecting the standard deviation of 0.007 mg/l for concentrations less than 0.4 mg/l, a relative standard deviation less than 1.75% for concentrations greater than or equal to 0.4 mg/l and less than or equal to 2 mg/I 20 and less than 6% for concentrations higher than or equal to 2 mg/l.
G This characteristic ensures that the measuring device obtained be considered as a breathalyzer and not as a breath analyzer. Moreover, it would be beneficial if the maximum tolerated error were 0.02 mg/I greater or less for concentrations less than 0,4 mg/I, that the relative maximum tolerated error be 5% for concentrations greater than or equal to 0.4 mg/I and less than or equal to 2mg/I and 20% for concentrations greater than or equal to 2 mg/I. Finally, the invention also requires the use of a semi-conductive reducing, gas sensor, using a variety of semi-conductivity of the material's conductivity in relation to the absorption of gas on this material. In the manufacturing of a pulsed infrared radiation delivery device emitting reproducible impulses in the [9pm, 10pm] spectral range] according to the invention. Brief description of designs Other characteristics and advantages of this invention will become apparent from the description made below, in reference to the attached figures which illustrate it as an example of creation with no limiting elements, and where: - Figure 1 is a diagrammatic arrangement of a infrared radiation delivery device according to the invention upon which appears an example of a period signal consisting of reproducible pulses such as provided in the entry of the delivery device of the invention; - Figure 2 represents diagrammatically an output module such as established in the device according to the invention, the figure 2A is in the top view and figure 2B is in cross-sectional view of the output module according an advantageous Realization of an emitter cone according to the invention; 7 - Figure 3 represents diagrammatically the essential elements of a device for measuring the concentration of a gas in a measurement tank by infrared absorption. Detailed description of the creation Figure 1 diagrammatically represents an infrared radiation delivery device according to the invention. This device consists of a ballast 1, capable of providing periodic pulsed I current or a tension V also periodic and pulsed. This tension V or current I provided at the entry of an output module 2, eventually equipped with an emitter cone 3, for the production of IR infrared radiation by output module 2. The power supply of the emitter is thus created by an electronic that allows for the generation of a signal consisting of regular pulses as represented in figure 2. Figure 3 represents the constitution of an output module 2 as such as that used in an infrared radiation delivery device according to the invention. As well as visible in figure 3B, the output module 2 includes a substrate 20 created with silicon or ceramic, on which a membrane 21 is placed. This membrane 21 is covered by an electric heat insulating layer 22 in which a conductive material layer is integrated. Another heat insulating layer 24 and heat distributor covers the entirety of layer 22 and of the conductive layer 23, before '25' metallization and a '25' metallic oxide active layers are disposed. This 26 active layer is the one that absorbs the gas whose concentration is to be measured when the 2 output module is used as a reducing gas sensor. The presence of the 21 membrane allows one to limit the thermal diffusion towards the 20 substrate and allows for a good stability of the thermal inertia, allowing for an improved reproducibility of impulses and of infrared radiation, such as those emitted by the 2 output module. We notice here that it is described as a reducing gas sensor based on semi-conductor technology. As well as the 21 membrane, the presence of 25 metallisation has an impact on the thermal inertia of the entirety of the 8 component. However, the functioning parts of the delivery of infrared radiation includes a 20 substrate, '22' and '24' thermal insulating layers, surrounding the 23 conductor, acting as resistance, and the 26 semi conductive layer. Its actually a matter of using the 23 thermally conductive metallic filament located under the 26 sensitive layer of the emitter. It is electronically isolated from the latter by another 24 layer which distributes the temperature. It is thus the filament + layer ensemble which emits infrared radiation. The output module is thus advantageously a semi-conducting component used as a reducing gas sensor, for example COHC or VOC gas. These sensors are generally created using metallic oxide on which the gas is absorbed. This absorption thus provokes the variation in resistivity, albeit by the electric conductivity of the 26 oxide metallic semi-conductive layer measured by the metallisation connectors. It is necessary, in order to observe the variation in resistivity, that this 26 layer be heated to significant temperatures, higher than 2500 in general. The role of the 23 heat resistance is thus, in the sensors, to heat the thin semi-conductive layer in order to allow the oxidation-reduction allowing for the particular gas to be detected. The heat resistance 23 may be realized with a platinum wire or another metal or even, in a more integrated way, with a doped polysilicon layer, whose '27' metallic connectors are made from a chrome-titanium-platinum alloy which allows for obtaining a satisfactory thermoelectric power. The 20 substrate is advantageously created in silicon or in ceramic. The 22 and 24 thermal insulating layers are advantageously created with silicon-based ceramic, for instance Si3n4 nitride silicon. The 21 membrane, which allows for limiting of thermal diffusion, can also be created with a ceramic material. It has for example a thickness of 3pm for a component of Li depth at the rate of 100pm. The characteristic width, marked L2 of the 26 active oxide metallic layer and of the 23 conductive layer is, typically, at the rate of 50pm.
9 The output module, as represented in figure 3, allows for working in pulsed mode, in a repeatable and reproducible manner. This avoids the utilisation of a bulky motor/chopper couple, usually necessary for infrared or monochromatic measures to obtain a signal with a signal report on exploitable noise. We note that the very weak bulking of power consumption of the infrared delivery device according to the invention allows for the creation of a very interesting infrared source for the measures regarding the concentration of gas by infrared absorption. Advantageously, the 2 output module is equipped with a 3 concentrator, in which a said emitter cone is dug whose surfaces are polished and coated with a 32 deposit in a way that reflects the infrareds. The ensemble constituted by the 2 output module and the 3 concentrator allows for the production of an infrared radiation delivery device completely adapted to a measurement of ethanol concentrations by infrared absorption. Figure 4 diagrammatically represents the essential elements of a portable standard deviation measurement tool functioning by infrared absorption. This tool allows for analysis of the alveolar alcohol concentration and uses a pulsed source of infrareds according to the invention. The use of the invention allows for the creation of portable standard deviations approved by the international legal metrology and whose measures may serve as references and legal proof within the framework of the measurement of alcohol in human breath. The utilisation of the source of infrared radiation impulses according to the invention allows for the integration of this technology on a reduced-size mobile tool and operating on its owns batteries.
10 In the measurement system particularly illustrated in figure 4, a 40 tubular measurement tank is equipped with 2 41 and 42 end pieces, each one repectively carrying an 2 infrared emitter according to the invention equipped with an 3 emitter cone and a 45 receptor cell. The 2 infrared emitter is linked to a 1 power module not represented in figure 3. The measurement system presented in this figure operates in mono-mode optic. The 41 and 42 end pieces include respectively an entry tubular structure of the 43 sample and an exiting tubular structure of the 44 sample. The 43 and 44 tubular structures are advantageously connected to a pumping system in order to ensure the circulation of the sample breathed by the user of the portable standard deviation tool. End pieces 41 and 42 also include advantageously a conical internal structure in order to pipeline the radiation in the tubular tank. The 45 receptor cell is advantageously a pyroelectric detector, this type of component allowing for the detection of thermal radiation in the spectrum of the domain from3pm. The range of responses for this type of detector vary between I and 200 Hz. The couple of emitter and receptor components used give an optimal signal for a frequency of roughly 5 Hz. Advantageously, the frequency used is between 4 and 8 Hz. We know that the pyroelectric effect translates by a modification of the natural polarization of the ferroelectric element of the sensor which Is made of crystal, The absorption of thermal radiation corresponds generally to a variation in temperature and translates by the appearance of electric charges on the surface. Nonetheless, at a constant temperature, the distribution of alternated charges must be neutralized by the free electrons and the surface potentials, in a way that no potential difference is measured. On the other hand, if the temperature changes rapidly, the moments of said internal poles change, which translates by the appearance of a potential transitory difference.
11 It is thus necessary that the source of infrared irradiation not be of a constant intensity in order to generate variations in polarisation and to allow for the detection of radiation. It is for this reason that the 2 infrared emitter must be pulsed at a given frequency thanks to adapted electronics. Advantageously, this frequency will be at the rate of 5 Hz for the desired implementations. Moreover, it must be noted that it is necessary that no condensation appears in the 40 measurement tank and, in particular to its extremities, that the 40 measurement tank be heated. The advantageous realization of such a heating consists of equipping the 40 measurement tank, on the outer face, of a resistance, not represented, rolling all along the length of the 40 measurement tank. This resistance allows for the achieving, in the 40 measurement tank, of temperatures at the rate of 400, higher than the maximum temperature that can the human breath can reach. This ensures the absence of condensation on the platework of the tank and of its extremities. Moreover, it is necessary that the 2 emitter equipped with its 3 emitter cone and the 45 receptor be protected from the breath of the user, which could involve chemical elements susceptible to deteriorating and operate as components. Also, each of these components is advantageously equipped with a 46 and 47 optical window of thick barium fluoride, for example, at the rate of 1.5 mm. The tightness of this window is ensured, advantageously, thanks to 46' and 47' donut-shaped joints. In the mode of creation presented in figure 3, 48 and 49 tightening nuts respectively hold the 2 emitter and pyroelectric receptor 45 in place.
12 The length of the measurement tank and its diameter are chosen in function of maximum tolerated errors and standard deviations as defined in the international OIML R 126 norm. Advantageously the 41 and 42 end pieces present conical angular opening sections between 7 and 300, and preferentially between 80 and 170, 12.5o on figure 4. We note finally that various implementations may be realized according to the principles of the invention.