Abstract:
A method and apparatus is disclosed which employs a pulse-controlled microdroplet fluid delivery system for precisely dispensing fragrances and other odor producing vapors. The pulse-controlled fluid delivery device is capable of ejecting microdroplets of fluid with a diameter less than 350 micrometers at a controlled ejection rate based upon inkjet printing technology. The pulse-controlled fluid delivery system includes mechanisms for vaporizing the fluids and delivery of the vapors to the nose, which is controlled by a programmable system controller capable of real time data-driven dispensing with a multi-fluid capability. Synthesis of custom fragrances is made possible by a multijet programmed control system which adjusts dispensing rates of components. Calibration of a prior art “electronic nose” is disclosed. A precise calibration gas is produced in real-time to counteract the effect of drifting.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 09/845,714, entitled “Method and Apparatus for Delivery of Fragrances and Vapors to the Nose”, filed on Apr. 30, 2001 and now U.S. Pat. No. 6,390,453, which is a continuation of U.S. patent application Ser. No. 09/176,818 filed Oct. 22, 1998 and now abandoned entitled “Method and Apparatus for Delivery of Fragrances and Vapors to the Nose”, which in turn was a continuation-in-part of prior application Ser. No. 60/062,727 filed Oct. 22, 1997 and now abandoned, the benefit of which is claimed in this application under 35 U.S.C. § or §119(e), as the case may be. 
    
    
     This invention was made with government support under a grant or contract awarded by the National Institute of Mental Health. The United States government may have certain rights in this invention. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to methods and apparatus for precisely dispensing fragrances and other volatile materials, synthesizing custom fragrances in real time and calibration of electronic sensors. 
     BACKGROUND OF THE ART 
     Odoriferous substances can be dispensed by numerous methods including passive wicks, aerosol “puffers”, fine particle sprayers and scented candles. Control of the initiation and cessation of sensory experience resulting from conventional dispensing is very difficult. Except in a gross sense, the quantity of odor producing material dispensed is not controlled. It is particularly difficult to cease producing an aroma sensation once begun and miniaturization is not readily achieved. Passive dispensing devices such as wicks or candles require material that remain relatively stable in air as a vapor and are able to withstand heat, for example. Materials which are readily oxidized at room temperature, photodecompose or hydrolyze in humid air are all examples of evanescent fragrances for which periodic active dispensing is the only practical way to produce the fragrance. 
     The most common method of dispensing fragrances or aromas is the wick method in which a wick in contact with a volatile liquid is exposed in a space. It is evident that once the wick is exposed, there is no way to control the amount of material dispensed nor to easily adjust it or quantify it. It can&#39;t conveniently be turned on and off. None of the conventional devices for distributing odor producing chemicals are subject to digital control or quantitative precision dispensing. 
     The prior art uses the same dispensing methods for the purpose of odor masking or eliminating vapors. Three approaches to removal of bad orders can be considered: A) perceptual masking, B) specific or nonspecific olfactory receptor blockade and C) odor molecule binding or metabolism. It would be desirable to have a precise active jet dispensing method for all three of these approaches because it allows the best odor removal materials to be dispensed interactively, in response to the presence of any specific bad odor. All of these strategies are in part used by companies such as EnviroCon, AMAX, Elim-N-Odor, Inc., BioZapp Labs, inc., Technaal, Inc.; and OdorGone (Ray Market). 
     Perceptual masking is an approach whereby a competing smell is introduced in a sufficient intensity to “mask” the offending odor whereby the subject is aware of both odors but with reduced attention paid to the offending odor. Olfactory receptor blockade can be an effective odor removal strategy if the offensive order is detected by a single receptor type in the nose whereby pharmacologic blockade of that specific receptor with a receptor blocking ligand, will produce a specific “smell blindness” for that smell. This is superior to the use of vapors of formaldehyde or cocaine or zinc oxide cream which have been used as non-specific receptor blocking agents which cause complete anosmia or hyposmia. Odor molecule removal by catabolysis of the molecule or binding another macromolecule to it can both remove the materials from the air and thus remove the odor. There are commercially available products intended to remove specific odors by one of these methods. All of these approaches could benefit from a device or method that would provide dispensing accuracy and precise control. 
     There is a significant need for accurate controlled dispensing of pharmaceuticals, herbs and psychoactive substances of all types. Potent psycho-active materials like cocaine, adrenalin, and amphetamine can be electronically dispensed from physician&#39;s direction using devices such as inhalers. Specific chemicals to control asthma are examples of such use. A more precise method of dispensing would be expected to produce an improvement in controlled dosage. Emergency personnel and military are obviously targets for emergency psycho-stimulant use. Nonprescription drugs like caffeine, nicotine, theopholine, ginseng, and others could also be dispensed in inhalable formulations for use in a variety of medical or even non-medical applications. Pheromones or other natural or synthetic materials that alter behavior and physiology via a nasal inhalation route are also subjects for precise controlled dispensing. Odoriferous materials that affect mood, arousal, stress or other dimensions of human behavior and physiology through primarily olfactory perceptual routes can benefit from improved dispensing apparatus. The invention of this application is a superior method for dispensing such compounds because dispensing can be precise, metered, interactive, and the dispenser can be tamperproof with prescribed dispensing rates possible. It would be desirable to have a dispensing device that was both discreet, digital and programmable, and in many foreseeable applications desirable to provide miniature devices which take up less space and are economical to manufacture and produce. The present invention makes these possible. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to ink-jet based systems for the micro-dispensation and vaporization of volatile materials obtained from odor producing fluids or materials which can be melted or dissolved in fluids. The invention relies upon tiny electronically operated fluid droplet ejection devices having a fluid supply reservoir and a droplet ejection orifice aimed to deposit fluid droplets onto a target medium or space. The fluid supply reservoir is provided with a viscosity adjusted odor sensation producing fluid which is ejected in a stream of sequential droplets in response to electrical signals comprising voltage pulses. The preferred fluid droplet ejection device comprises one or more piezoelectric actuators but ejection devices can be made with other types of actuators such as magnetoresistive, inductive, thermal or miniature pressure solenoid valve. Pulses are provided by drive electronics operably connected to the ejection device or a plurality of such ejection devices and a system controller operably connected to the drive electronics and a power source whereby operating signals are delivered to the drive electronics to cause sequential droplets of fluid to be deposited onto the target medium or space. A typical orifice size is approximately 60 micrometers. Droplets in the range of 10 micrometers to over 350 micrometers are possible by varying known parameters of ink-jet printing heads. 
     In one embodiment the fluid droplet ejection device or devices are enclosed in a housing containing a target medium and air-flow outlet. In a variation of the invention, the target medium is a heater having a heated surface operated by the system controller and positioned to intercept ejected droplets deposited thereon. Air moved by an air movement device may be used to increase volatilization of fluid deposited on the target medium by the ejection device. The heater has little or no heat sink characteristics because of its low mass and small size. The heater has a quickly heatable surface upon which fluid droplets are deposited which equally quickly falls back to ambient temperature when not powered. 
     In a further variation, the heater is a plurality of heaters individually controlled to quickly raise the temperature of the heatable surfaces to vaporized fluid droplets deposited thereon when the ejection device is operated and return to an unheated state when ejection ceases in order to control vaporization of deposited fluid. In some applications the heater temperature is preset, based upon the fluid being ejected, and held constant at the specified temperature. Air movement means may be used to force air over the heated surface or surfaces and thereby carry vapor from a passageway through the air-flow outlet. Individual fluid droplet ejection devices including the reservoir have been produced having a length less than one centimeter and a diameter less than two millimeters. Such miniaturization makes new applications and methods possible in connection with dispensing fragrance, aroma and odor producing materials. 
     The present invention has utility in applications such as a virtually reality display system for entertainment or training, instrumentation including medical instrumentation, conditioning of environments, odor masking systems, fragrance synthesis, medication delivery, computer output systems (fragrance display), communication systems and calibration inputs for electronic chemical sensor systems. 
     In another embodiment of the invention, a printhead having a plurality of electronically operated fluid droplet ejection channels each having a fluid supply reservoir containing volatile fluids which produce different aromas or fragrance components. The channels are selectively operated by a system controller to deposit fluid on a target medium where they can volatilize to produce a custom aroma or fragrance In combination with a programmed computer which selectively operates the fluid droplet ejection channels in different combinations or at different rates or upon differentially heated surfaces, a unique and reproducible fragrance or aroma can be produced and reproduced. By altering the selection of fragrance components or the relative amounts thereof, an original odor effect can be quickly and precisely changed to produce a second or a third or more different odor effect merely by changing the voltage pulse signals which operate selected channels. 
     The microdispensing ink-jet based systems of the present invention allow the study of numerous properties of the sense of smell, including studies of temporal integration times, inter-nostril summation, backwards and forwards masking, and other phenomena that have only received cursory attention due to methodological limitations based on existing systems. The microdispensing ink-jet based systems of the present invention provide precise control of both the temporal envelope of the stimulus and the total number of molecules constituting the stimulus. Although conventional olfactory testing machines are available, only large well-funded organizations can afford them because of high costs. 
     The present invention provides a means for conducting such research at a fraction of the cost of conventional olfactory research testing equipment. In addition, it overcomes disadvantages and drawbacks of existing olfactory test and sensory stimulation formats because it is fully automatic, more convenient, faster and more precise. Because ink-jet dispensing of airborne materials is precise, discrete, digital, programmable and interactive, the speed and accuracy of dispensing materials to become airborne is several orders of magnitude better than can be obtained by any other method. Moreover, because devices can be made small, the size of the systems can be reduced to a few cubic inches. Since the present invention is controlled by digital electronics, all types of digital computer and interactive control is possible. Many different rates, intensities and combination of airborne materials can be presented at a mere keystroke or switch closure. Because the systems of the present invention can dispense volumes as small as a few tens of picoliters of fluid, they can provide exquisitely fast and precise olfactory inputs near the threshold (approximately 10 billion molecules) of human olfactory. 
     The miniature size of the devices of the present invention make novel applications possible. The devices can be fitted inside any air handling systems (such as scuba airways, pilot airways, automotive air handlers, etc.), and can be worn (on glasses, helmets, decorative pins, microphone holders, etc.) or can be concealed near objects (in headrests, door jambs, table centerpieces, television chassis, etc.). All of these applications open exciting new horizons to olfactory access not heretofore available. Other patent applications in related art by inventors with an obligation to assign to the owner of the present application are U.S. application Ser. No. 08/837,646, filed Apr. 21, 1997 entitled “Presenting Airborne Materials to the Nose”, and U.S. Ser. No. 09/110,486, filed Jul. 6, 1998, entitled “Method and Apparatus for Dispensing Airborne Materials for Controlling Pests, incorporated by reference herein. 
     An interesting commercial application of the present invention lies in the entertainment field in the installation of a plurality of ink-jet dispensing systems throughout a movie theater and programmed to quickly produce odors synchronized with the film being shown. They can be quickly turned on or turned off under programmed control to enhance the theater going experience. 
     Finally, the precise control offered by the ink-jet based dispensing system of the present invention can be used as a real time calibration source for electronic sensors which, although in their infancy are the subject of considerable developmental activity as a means for detecting and measuring odors. Calibration of these devices is particularly significant because they are known to drift in response to ambient conditions such as temperature and relative humidity. The reproducible delivery of a known quantity of a known material makes real time baseline calibration possible. In the converse of this, electronic sensors can be used to verify the operation of the ink-jet dispenser where it is important to make sure the dispenser is functioning. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates an odorous fluid being ejected from the orifice of an ejection device; 
     FIG. 2 schematically represents a four fluid, multi-jet printhead of the type commonly used for ink-jets; 
     FIG. 3 represents a multi-fluid jetting device with an electrical interconnect on the side; 
     FIG. 4 represents a multi-fluid jetting device with fluid reservoirs and support hardware; 
     FIG. 5 represents a printhead made with an array of single jet devices, each with its own fluid input; 
     FIG. 6 is a block diagram of the control system for a fragrance ejection device; 
     FIG. 7 schematically illustrates a fragrance ejection device with a heated target, air-flow, and control components, with the side cover removed; 
     FIG. 8 is an alternate fragrance ejection device including a flow-through target and the use of heated air; 
     FIG. 9 is a printhead having a heater attachment so that the printhead temperature can be controlled above room temperature; 
     FIG. 10 illustrates a fragrance ejection device mounted on a microphone together with a computer monitor and keyboard comprising a control system to synthesize fragrances; 
     FIG. 11 is an exemplary screen for the system of FIG. 10 whereby settings can be adjusted to vary the percentages of components by operating individual ejection devices of a printhead; 
     FIG. 12 is a high level flow chart for the fragrance synthesizing system illustrated in FIGS. 10 and 11; 
     FIG. 13 is a headset with a microphone having a fragrance ejection device mounted thereon; 
     FIG. 14 is a schematic enlargement showing the components inside the mouthpiece of the headset of FIG. 13; 
     FIG. 15 illustrates how a virtual reality head-set can include a fragrance ejecting device to enhance the experience; 
     FIG. 16 shows a fragrance dispensing stand with an ejection device and a remotely located blower exposed for viewing; 
     FIG. 17 is an enlarged cut away view of the ejection device assembly from the fragrance dispensing stand of FIG. 16; 
     FIG. 18 is a cut away view of a preferred form of the ejection device used in the ejection device assembly of the fragrance dispensing stand of FIGS. 16 and 17; 
     FIG. 19 is an alternate head for the fragrance dispensing stand of FIGS. 16 and 17 with the blower mounted in the head; 
     FIG. 20 depicts data showing a temporal response of different rates of dispensing fragrances; 
     FIG. 21 illustrates the temporal response of a three-fluid dispensing system including a schematic of the system and an air-flow channel; 
     FIG. 22 presents droplet information data from one channel of a multi-fluid jetting device; 
     FIG. 23 is a schematically illustrated system for calibrating a sensor array commonly referred to as an “electronic nose”; 
     FIG. 24 is an enlarged view of a portion of the system of FIG. 23 showing the microjet ejecting device and a heated target medium generating a calibration gas; 
     FIG. 25 illustrates the drift in signal of a sensor over time; 
     FIG. 26 illustrates the use of the microjet ejection system of FIG. 23 to present known concentrations of calibration gas to the sensor in real time; 
     FIG. 27 illustrates the signal response of a sensor when exposed to a finite concentration of volatile organic chemicals. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the description that follows, like parts will be referred to by the same name and reference numeral in so far as possible. The invention relies upon the precision dispensing and subsequent vaporization of one or more fragrance, aroma, or odor producing fluids into the air for use in a variety of applications. Airborne materials are micro-dispensed into inspired airstreams or personal air space of one, two, or more subjects or a testing space. The airborne materials are presented in a form of a substance containing a volatile component. 
     Table 1A includes a common name of a variety of different materials having volatile components which are readily recognized by the human nose when presented in sufficient concentration. Many other such materials are known which are produced from natural substances or synthesized. Such materials are listed non-exhaustively in Table 1B. 
     
       
         
               
               
               
             
           
               
                   
                 TABLE 1A 
               
               
                   
                   
               
             
             
               
                   
                 Peanut 
                 Watermelon 
               
               
                   
                 Soap 
                 Grass 
               
               
                   
                 Paint Thinner 
                 Natural Gas 
               
               
                   
                 Motor Oil 
                 Cinnamon 
               
               
                   
                 Smoke 
                 Pineapple 
               
               
                   
                 Lemon 
                 Coconut 
               
               
                   
                 Menthol 
                 Dill Pickle 
               
               
                   
                 Onion 
                 Clove 
               
               
                   
                 Licorice 
                 Banana 
               
               
                   
                 Wintergreen 
                 Garlic 
               
               
                   
                 Orange 
                 Peach 
               
               
                   
                 Lilac 
                 Lime 
               
               
                   
                 Grape 
                 Leather 
               
               
                   
                 Gasoline 
                 Gingerbread 
               
               
                   
                 Bubble Gum 
                 Cheddar Cheese 
               
               
                   
                 Chocolate 
                 Musk 
               
               
                   
                 Mint 
                 Cedar 
               
               
                   
                 Root Beer 
                 Apple 
               
               
                   
                 Cherry 
                 Black Pepper 
               
               
                   
                 Strawberry 
                 Chili 
               
               
                   
                 Fruit Punch 
                 Tomato 
               
               
                   
                 Rose 
                 Pumpkin Pie 
               
               
                   
                 Turpentine 
                 Skunk 
               
               
                   
                 Pine 
                 Whiskey 
               
               
                   
                 Pizza 
                 Honey 
               
               
                   
                   
               
             
          
         
       
     
     
       
         
               
             
           
               
                 TABLE 1B 
               
               
                   
               
             
             
               
                 ALDEHYDES - Organic chemicals derived from natural or synthetic 
               
               
                 materials. Aldehydes add a vivid, quick quality to top notes. 
               
               
                 Variations can be powdery, fruity, green, citrusy, floral or woody. 
               
               
                 AMBER - A fossil resin from the fir tree. Prized for its tenacity, it 
               
               
                 also adds warm, leathery, powdery elements to a composition. The 
               
               
                 color amber refers to the color of the resin 
               
               
                 AMBERGRIS - Secretion from the male sperm whale, often found 
               
               
                 floating in the ocean. The Chinese once used it as an aphrodisiac. 
               
               
                 Ambergris imparts a woody, balsamic odor. Substitutes are used 
               
               
                 more often today, because the natural substance is difficult to 
               
               
                 obtain. 
               
               
                 AMBRETTE SEED - These plant seeds yield a musky floral, brandy- 
               
               
                 type aroma. 
               
               
                 ANJELICA - Oil from the root of the angelica tree, which is 
               
               
                 cultivated in France, Belgium and Germany. It is musky and peppery, 
               
               
                 with a spicy green quality. 
               
               
                 BALSAM - Tree resins that exhibit a warm, sweet element. They are 
               
               
                 generally used as a base fixative. 
               
               
                 BASIL - A spicy herb with a green impression. 
               
               
                 BAY LEAF - A tree leaf valued for its spicy, warm, almost bitter scent. 
               
               
                 BAYBERRY - A shrub with berries, from which a waxy substance is 
               
               
                 taken. Bayberry adds a spicy, woody flair to fragrance. 
               
               
                 BENZOIN - Balsamic resin from the tropical styrax tree, used as a 
               
               
                 fixative, imparting a sweet, coca-like quality. Benzoin is found in 
               
               
                 Thailand, Vietnam and Laos. 
               
               
                 BERGAMOT - Oil produced from the peel of the bergamot fruit. The 
               
               
                 inedible fruit is of the citrus family and is about the size of an 
               
               
                 orange. The largest bergamot production comes from Calabria, Italy. 
               
               
                 The fresh, citrus essence is ideal in top notes and eau de cologne. 
               
               
                 BLACK CURRANT BUD - (see Cassis) 
               
               
                 BORONIA - Essence taken from the flower of the boronia bush, which is 
               
               
                 mainly found in Australia. Often used in chypre blends, it leaves a spicy- 
               
               
                 rosy impression. 
               
               
                 BROOM - This produces a sweet, grassy odor. It is derived from the 
               
               
                 blossoms of the Mediterranean-area Spanish broom shrub. 
               
               
                 BUCHU - Substance from the leaves of the buchu herb. It yields a strong 
               
               
                 minty, camphor odor. 
               
               
                 BULGARIAN ROSE - A highly valued flower in perfumery, grown in 
               
               
                 Bulgaria&#39;s Valley of the Roses at the base of the Balkan mountain 
               
               
                 range, where a Turkish merchant began cultivation centuries ago. 
               
               
                 CARDAMOM - Oil distilled from the cardamom plant, a member of the 
               
               
                 ginger family. It leaves a spicy floral impression. It is second 
               
               
                 only to saffron as the world&#39;s most expensive spice. In India, 
               
               
                 Cardamom grains are chewed to freshen the breath. 
               
               
                 CARNATION - This flower gives off a spicy, sensual aroma. 
               
               
                 CASSIA OIL - Obtained from the leaves of an evergreen tree, valued for 
               
               
                 its spicy cinnamon-like quality. The oil is also used in cola drinks. 
               
               
                 CASSIE - Derived from the  Acacia farnesiana  bush, the cassie absolute 
               
               
                 produces a spicy floral flavor. 
               
               
                 CASSIS - Oil taken from the bud of the black currant fruit, which is 
               
               
                 also used in liqueur. 
               
               
                 CASTOREUM - A secretion from the beaver that exudes a leathery 
               
               
                 quality and is used as a fixative. 
               
               
                 CEDARWOOD - Oil obtained from the juniper cedar tree, which is a 
               
               
                 native to Texas. An excellent fixative, it has a distinct wood tone. 
               
               
                 CHAMOMILE - A sweet, herbal odor with fruity notes, often used to 
               
               
                 balance floral compositions. 
               
               
                 CINNAMON - Oil obtained from the bark and leaves of the cinnamomum 
               
               
                 tree, which is native to Southeast Asia and the East Indies. It 
               
               
                 imparts a familiar warm, sweet, spicy odor. 
               
               
                 CIVET - A glandular secretion from the civet cat, used as a fixative. 
               
               
                 Repugnant by itself, civet blends well and adds a warm, leathery, 
               
               
                 erotic tone to a composition. 
               
               
                 CLARY SAGE - An herb valued for its sweet, subtle quality. 
               
               
                 CLOVE - Obtained from the clove tree, clove buds are prized for their 
               
               
                 spicy sweetness. The tree is cultivated in Sri Lanka, Madagascar and 
               
               
                 Indonesia. 
               
               
                 CORIANDER - Oil from the coriander herb of the parsley family, valued 
               
               
                 for its spicy aromatic impression. 
               
               
                 COSTUS - Essence from the root of the costus plant of the plant of the 
               
               
                 daisy family, lends warmth to Oriental blends. It has green, violet- 
               
               
                 like accents. 
               
               
                 COUMARIN - Obtained from the tonka bean and often created 
               
               
                 synthetically, produces a sweet, herbal, spicy, hay-like odor, similar 
               
               
                 to vanilla. 
               
               
                 CYCLAMEN - Essence taken from the heart-shaped flowers of the 
               
               
                 primrose family. 
               
               
                 EUCLYPTUS - Oil from the leaves of the eucalyptus tree, leaves a strong 
               
               
                 herbal, camphor impression. Discovered in Tasmania, it is widely 
               
               
                 cultivated in Spain, Portugal and Australia and is well priced. 
               
               
                 FRANGIPANI - Oil from the sweet, jasmine-like flowers of the frangipani 
               
               
                 tree. 
               
               
                 GALBANUM - A gum resin valued for its leafy green, soft balsamic 
               
               
                 odor. Galbanum is used in many fragrances to provide a pleasing 
               
               
                 freshness, or green lift. 
               
               
                 GARDENIA - A heady white flower with a strong sweet scent. 
               
               
                 GERANIUM - Oil made from the leaves and stems of the plant. 
               
               
                 Depending on the variety, it gives off a rosy, minty or fruity essence 
               
               
                 often used in rosy or spicy compositions. 
               
               
                 GUMS - Resins or balsams secreted from plants. Exhibiting a sweet 
               
               
                 tenacious odor, they are often used as fixatives. 
               
               
                 HELIOTROPIN - An aldehyde with a floral almond tone, found in 
               
               
                 pepper oil. 
               
               
                 HONEYSUCKLE - A highly fragrant vine flower but difficult to capture 
               
               
                 correctly. The essence of the honeysuckle is usually re-created by 
               
               
                 blending a variety of florals. 
               
               
                 HYACINTH - A sweet floral that imparts a green impression. 
               
               
                 INCENSE - Made from gums and resins, produces a spicy aroma when 
               
               
                 burned. 
               
               
                 JASMINE - Called the king of flowers, a sweet tiny white flower with 
               
               
                 a vibrant, smooth aroma. Jasmine is one of the most prized essences 
               
               
                 in the perfumer&#39;s palette. It is grown in France, Morocco, India, 
               
               
                 Egypt and Spain and must be harvested before sunrise to retain the 
               
               
                 full amount of its delicate fragrance. 
               
               
                 JONQUIL - Highly fragrant essence derived from a flower of the 
               
               
                 narcissus family, rare because it is difficult to distill. 
               
               
                 LABDANUM - A dark resin obtained from the rockrose herb, valued for 
               
               
                 its leathery odor. 
               
               
                 LAVENDER - From the flowering tops of lavender plants in France, 
               
               
                 Spain, Morocco and old Yugoslavia, a sweet, light essence with 
               
               
                 woody floral accents. The oil is used in lavender waters, chypres, 
               
               
                 fougeres and florals. Lavender water is said to have been a favorite 
               
               
                 of Madame de Pompadour, mistress of Louis XV 
               
               
                 LEATHER - A smoky, sweet, animal odor crafted from the 
               
               
                 perfumer&#39;s palette. It is warm and persistent. 
               
               
                 LEMON - Oil from the lemon rind. It is a zesty, sharp, refreshing 
               
               
                 essence, and is added to brighten many compositions, particularly 
               
               
                 eau de cologne. 
               
               
                 LILAC - Since the essence released by the lilac plant and flower 
               
               
                 does not accurately portray its aroma, the perfumer re-creates the 
               
               
                 essence by using jasmine, ylang-ylang, neroli and vanilla. 
               
               
                 LILY OF THE VALLEY - Also known as muguet, lily of the valley is 
               
               
                 invented by the perfumer, using jasmine, orange blossom, rose, 
               
               
                 ylang-ylang and chemical additives. The sweet essence is difficult to 
               
               
                 obtain from the natural flower. 
               
               
                 MAGNOLIA - A sweet, highly fragrant flower, also stubborn in releasing 
               
               
                 its essence. The perfumer re-creates the essence by blending rose, 
               
               
                 jasmine, neroli and ylang-ylang with aroma chemicals. 
               
               
                 MANDARIN - Oil from the peel of the mandarin orange fruit, a brisk, 
               
               
                 sweet essence often used in eau de cologne. 
               
               
                 MAY ROSE - Also called rose de mai. The May rose from Morocco 
               
               
                 produces a rich, long-lasting oil prized for its full-bodied, 
               
               
                 diffusive qualities. 
               
               
                 MIMOSA - A green floral essence obtained from mimosa green flowers 
               
               
                 and stems. It imparts a smooth, sweet aroma. 
               
               
                 MOSS - Earthy essences are derived from a variety of mosses: 
               
               
                 oakmoss, treemoss, lichen, seaweed and algae. 
               
               
                 MUSK - A glandular secretion from the male musk deer from Tibet, 
               
               
                 China and Nepal, used as a fixative in fine perfumes. It is valued 
               
               
                 for its woody, animal, erotic impressions, though nowadays it is 
               
               
                 often created chemically by the perfumer. Soft, sensuous, pervasive. 
               
               
                 MUGUET (see Lily of the Valley) 
               
               
                 NARCISSUS - A highly fragrant yellow and white flower that produces 
               
               
                 an intense spicy, earthy and sweet straw-like odor. Small amounts 
               
               
                 are often used to round off floral compositions. Native to Persia, 
               
               
                 the narcissus flower was carried to China over the silk route in the 
               
               
                 eighth century. 
               
               
                 NEROLI - Made from the orange blossoms of the bitter orange tree 
               
               
                 grown in France, Egypt, Algeria and Morocco. It is light, sweet 
               
               
                 and spicy and is used in top notes and eau de cologne. It was named 
               
               
                 for the Duchess of Nerola and was often used to scent gloves. 
               
               
                 NUTMEG - Spicy oil derived from the seeds of the South Asian nutmeg 
               
               
                 tree. 
               
               
                 OAKMOSS - A lichen grown on oak trees. Its odor is earthy, woods 
               
               
                 and slightly leathery. It is used as a fixative in many blends, 
               
               
                 especially chypre. 
               
               
                 OLIBANUM - Also called frankincense. Olibanum is a gum resin from a 
               
               
                 tree found in Africa and Saudia Arabia. A fixative, its odor is 
               
               
                 spicy and balsamic, similar to odor of incense. 
               
               
                 OPOPANAX - Derived from a gum resin and is similar to myrth. A 
               
               
                 woody, sweet fixative. 
               
               
                 ORANGE OIL - Produced from the peel of the orange, and often used 
               
               
                 in eau de cologne and floral fragrances. Refreshing, sweet, fruity 
               
               
                 and crisp. 
               
               
                 ORANGE BLOSSOM - From the white blossoms of the bitter orange tree. 
               
               
                 It adds a warm, spicy flavor that is often used in floral compositions. 
               
               
                 ORRIS - One of the most expensive ingredients used in perfumery. It 
               
               
                 is obtained from the iris plant, which is commonly cultivated in Italy. 
               
               
                 Its odor is violet-like and can be warm, sweet, woody, fruity or floral, 
               
               
                 depending on the quality. 
               
               
                 OSMANTHUS - Produced from the flowers of the osmanthus tree, which 
               
               
                 is found in Japan, China and Southeast Asia. It has a floral odor, with a 
               
               
                 hint of plum and raisin. 
               
               
                 PATCHOULI - Oil obtained from the leaves of the patchouli plant, a 
               
               
                 superb fixative. Discovered in India, it is also cultivated in 
               
               
                 Malaysia and Indonesia. Its odor is earthy, dry, woody and spicy. 
               
               
                 Patchouli is often used in Oriental and chypre blends. 
               
               
                 PETITGRAIN - Essence derived from the leaves and stems of the bitter 
               
               
                 orange tree. It has a subtle woody tone similar to neroli. Sweet and 
               
               
                 floral, petitgrain and freshness to a fragrance, especially eau de cologne. 
               
               
                 RESIN - Gum secretions from trees and plants, often used as fixatives. 
               
               
                 ROSE - Rose oil is also referred to as “otto” or “attar” of rose; these 
               
               
                 terms refer to perfume oil produced through distillation. There is a wide 
               
               
                 variety of roses, and the rich oil they produce has the familiar rose aroma, 
               
               
                 though undertones vary from honey to fruity, spicy to musk, and violet to 
               
               
                 green. Called the queen of flowers, it is one of the most precious 
               
               
                 ingredients in perfumery. Roses bloom just thirty days of the year and 
               
               
                 must be picked quickly, for they lose half their essence by noon. Centifolia 
               
               
                 and Damascena are popularly cultivated roses. The floral essence is used 
               
               
                 in rose water, floral, chypre and Oriental compositions. Rose water was 
               
               
                 said to have been a favorite of Marie Antoinette. 
               
               
                 ROSEMARY - Flowers and leaves of the evergreen rosemary herb of the 
               
               
                 mint family, distilled for use in perfumery. The oil produces an herbal 
               
               
                 note that is woody and slightly lavender-like. 
               
               
                 ROSE DE MAI (see May Rose) 
               
               
                 ROSEWOOD OIL - Oil obtained from the wood of the rosewood tree, the 
               
               
                   aniba rosaeodora  of the laurel family. 
               
               
                 SAGE - A fresh, spicy odor from the sage herb. 
               
               
                 SANDALWOOD - Oil from the sandalwood tree, the evergreen  santalum   
               
               
                   album  grown in india, Australia and Southeast Asia, though the Indian 
               
               
                 province of Mysore supplies 85% of all sandalwood. The wood is valued 
               
               
                 for its aroma and its imperviousness to termites. The trees must 
               
               
                 mature at least thirty years for the oil to fully develop. An expensive 
               
               
                 ingredient, sandalwood oil is prized for its fixative quality. Its 
               
               
                 odor is powdery, balsamic, wood and rich. Sandalwood gives a smooth 
               
               
                 finish to Oriental, chypre and floral perfumes. 
               
               
                 STYRAX - A sweet balsam found on the styrax tree, an excellent fixative 
               
               
                 SWEET PEA - A flower oil produced from the fragrant flowering vine, 
               
               
                 valued for its light, delicate nature. 
               
               
                 TAGETES - Essence produced from the tagetes flower, which is grown in 
               
               
                 Spain, Italy and South Africa. The strong essence has an herbal, 
               
               
                 aromatic personality with fruity undertones 
               
               
                 THYME - Derived from the flowering herb. Thyme smells sweet and 
               
               
                 herbaceous - ideal for eau de cologne. 
               
               
                 TONKA BEAN - Fragrant seeds from native South American trees of the 
               
               
                 Dipteryx family. 
               
               
                 TUBEROSE - One of the most expensive oils, from a flower known for 
               
               
                 its rich, sensual aroma. Its cost is due in part to a painstaking 
               
               
                 processing called enfeurage, then the oil is separated with alcohol. 
               
               
                 Tuberose is a perennial plant native to Mexico. The sweet, honey-like 
               
               
                 aroma adds to fullness to many floral fragrances and blends well with 
               
               
                 gardenia, jonquil and hyacinth. 
               
               
                 VIOLET - The violet flower yields such a minute amount of oil that it 
               
               
                 is cost prohibitive to extract. Instead, the violet aroma is created 
               
               
                 chemically for use in perfumery. 
               
               
                 VANILLA - Made from the fruit and seeds of a climbing orchid vine. It 
               
               
                 has pods, or capsules encasing the beans. Vanilla is an impressive sweet 
               
               
                 fixative, used in many Oriental, amber and floral perfumes. 
               
               
                 VANILLIN - Can be produced naturally from the vanilla pod, and from 
               
               
                 certain balsams and benzoins. It can also be made synthetically. Its 
               
               
                 sweet, strong odor is similar to vanilla, but lacks the depth of 
               
               
                 vanilla. Vanillin blends well with vanilla to produce a round, full- 
               
               
                 bodied vanilla aroma. 
               
               
                 VETIVER - A grass grown in Haiti, Reunion Island, Brazil, China and 
               
               
                 Southeast Asia. It has a woody, earthy quality, enhanced by a moist 
               
               
                 balsamic accent. A superb fixative vetiver is an important component 
               
               
                 in chypre blends. 
               
               
                 VIOLET LEAF - Oil from the leaves of the violet plant, valued for its 
               
               
                 cumcumbery green and peppery herbal aroma, with touches of violet and 
               
               
                 iris. Parma, Italy, is known for its violet production. 
               
               
                 YLANG-YLANG - From Tagalong for “flowers of flowers.” This oil 
               
               
                 comes from the flower of ylang-ylang trees grown in Madagascar, 
               
               
                 Indonesia, Comoros and the Philippines. The rich oil has a jasmine-like 
               
               
                 aroma and sweet balsamic accents. used in many floral and Oriental 
               
               
                 compositions. Ylang-ylang smooths and rounds bitter notes, adding 
               
               
                 warmth and grace. 
               
               
                   
               
             
          
         
       
     
     FIG. 1 is a representation of an actual photograph of an ejection device denominated  10  showing only a portion of the nozzle  12  having an orifice  14 . The orifice  14  is normally conical in shape as shown, tapering forward to the smallest diameter where a liquid meniscus is present from which the droplets emerge. Two different liquids are shown being ejected from jetting device  10 . A droplet  16  of the fragrance Woody is shown on the left and a droplet  18  of the fragrance Rose is shown on the right. Many different fluids can be dispensed with similar results. A large number of such fluids have been demonstrated and are referenced in the background section of this application. The droplet sizes in FIG. 1 are approximately 60 micrometers although the creation of droplets for this technology range from droplets having diameters of about 10 micrometers to over 350 micrometers in diameter. Droplet sizes can be varied by altering the signals provided to a single device as demonstrated in U.S. Pat. No. 5,461,403 which is incorporated herein by reference. While the Woody and Rose droplets are being sequentially produced with individual ejection devices  10 , it is evident that the method can simultaneously eject these components at the same or different rate to produce a “Woody-Rose” combined fragrance. 
     FIG. 2 schematically illustrates a multi-fluid printhead  20 . The front of printhead  20  has an orifice array  22  having four multiple orifice regions  24 , each of which is for a different fluid. Each of four fluids are supplied by four individual fluid reservoirs  26  which pass through between upper body  28  and main body  32  of device  26  to supply fluid to channels  30 , which can be controlled separately to eject fluid on demand. Layers that form the channel are seen on the side of device  20  but the channels themselves are hidden within the area between the upper body  28  and a lower main body  32 . The back end portion  34  supplies electrical connections to drive the printhead  20 . Main body  32  of this particular printhead is made of piezoelectric material called PZT. The PZT is the actuator material that drives the printhead. This type of construction is disclosed in U.S. Pat. Nos. 5,208,980, 5,227,813 and 5,402,162 which are incorporated herein by reference. Although this type of printhead has channels actually cut or formed in blocks of PZT material, it is evident that individual ejection devices  10  can be combined in the manner indicated in FIG. 5, where the “channel” is an individual tube connected to a reservoir to supply the volatile fluid for ejection. It should be understood herein that the term printhead comprehends both such types of devices. 
     FIG. 3 schematically discloses a jetting device  36  for ejecting multiple fluids in a slightly different configuration and with eighteen different fluid inputs  38 . The device has a PZT body  40  with an electronic connection  42  shown as an interconnect substrate on the underside of printhead  36 . Printheads of this type are disclosed in U.S. Pat. Nos. 5,435,060 and 5,666,145 which are incorporated herein by reference. 
     FIG. 4 is an ejection device  46  similar in construction to FIGS. 2 and 3, showing a plurality of larger fluid reservoirs  48  can be arranged in fluid communication with a smaller printhead mounted in a support structure  50 . A plurality of tubular connections  52  connect the inlet to the printhead of fluid reservoirs  48  through fluid reservoir covers  54 . A plurality of connectors  56  are shown for loading fluid into reservoirs  48 . The specific sizes and materials for use in contact with the variety of fluid components to be dispensed is within the knowledge of someone skilled in the art. Although only nine fluid reservoirs are shown, ejection systems with many more fluid reservoirs could be used. Fluid can be pre-filtered before loading them into the reservoirs or small filters can be installed between fluid reservoirs  48  and the printhead  46 . 
     FIG. 5 illustrates a printhead  58  containing nine single ejection devices  60  mounted in support structure  62 . Devices  60  comprise a glass tube  64  with an orifice  66  at the end. Glass tube  64  is bonded to a piezoelectric element  68  covered with an electrode layer. The piezoelectric element is exposed at a small section  70  that separates the electrode from another electrode  72  which extends around the end of the piezoelectric element and covers the inside of the piezoelectric tube element  68 . Plastic tubes  74  are connected to the ends of the glass tubes  64  farthest from the orifice. Plastic tubes  74  would connect to fluid reservoirs (not shown). Metalization on the outside of the piezoelectric material is connected to independent leads  76  which allows each device  60  to be fired separately. The common electrical connection  78  is connected to electrodes  72  which electrically connects the inside of the piezoelectric tubes. The devices shown in FIGS. 2,  3 ,  4  and  5  are shown to reveal variation of the printhead design and types of fluid and electrical elements; but in no way should it limit the invention to these specific designs. This type of design is illustrated by U.S. Pat. No. 5,053,100 and U.S. Pat. No. 5,681,757 which are incorporated by reference herein. 
     FIG. 6 illustrates schematically a block diagram for a control system  80  for a complete fluid ejection system. Not all elements shown in the diagram may be present in every system, but their presence will depend upon the particular application. System controller  82  may be programmed to send signals to airflow controller  84  which controls an air movement device  86  which may comprise a fan or blower or compressed gas. Controller  84  could be nothing more than a switch to turn off a blower  86 . Heater controller  88  also under control of system controller  82  may control power to one or more heaters  90 ,  92  comprising heatable surfaces used in the system. The location and types of heaters will become clear from further discussion in connection with the applications. Drive electronics  94  creates the voltage pulses that drive the piezoelectric actuator of the dispenser or dispensers  96 . System controller  82  may be programmed to signal drive electronics  94  to deliver or to terminate certain types of pulses necessary to fire one or more individual ejection device and may download the voltage wave form to the drive electronics in connection with this task. Maintenance controller  98  and maintenance hardware  100  may be included for the purpose of keeping the ejection device or devices functioning. For example, it may wipe the orifice array on command from the system controller. In many applications it will not be necessary. Sensors  102  may be used with the system to monitor a specific parameter and feed back information representative of the parameter to controller  82 . For example, one type of sensor  102  could monitor the temperature of a specific location, for example the heater temperature or the ejection device temperature. Another type of sensor could monitor the vapor density or relative humidity in the ejection area. FIG. 6 shows the sensors  102  feeding back information to the system controller. It could feed information back to an individual element controller. Communication system  104  may be used to feed command signals to system controller  82 . This could be as simple as a switch or it could include inputs from a computer system. Other types of communication devices  104  could be radio signals, a network connection, a motion sensor, etc. The system controller and communication system can be combined into one unit. 
     A fragrance ejecting device  106  is schematically illustrated in FIG. 7 as containing many of the elements of FIG.  6 . It is mounted in a housing  107 . Power source  109  for the device may be a battery for mobile devices. Printhead  108  could be a printhead like the printheads disclosed in the previous figures or a printhead comprising a single ejection device. Printhead  108  dispenses droplets  110  onto a heated surface  112  of a heater  114 . Heater controller  116  monitors the signal from temperature sensor  118  to control the surface to a set-point by adjusting power to the heater. 
     Printhead  108  is driven by drive electronics  120  which receives control signals from system controller  122 . Fluid to be jetted is stored in reservoir  124  in fluid communication with the ejection element of printhead  108  through a capillary. Blower  126  creates air-flow which carries vapor through an air-flow channel or passageway  128  bounded by surfaces  130 ,  132 . Air/vapor may pass out of the device through airflow outlet  134  which may be provided with a grating or permeable cover. Although the device has been shown as having a powered air movement device, it should be understood that in some cases convection or diffusion may be used to transmit air/vapor out of the device in which case a blower might not be needed. A temperature sensor might not be used in some cases where the heater is controlled simply by a specified resistance and voltage. Therefore, not all elements discussed in FIG. 7 need be used for a fragrance ejection device. It should also be understood that the printhead can have more than one orifice and more than one fluid can be provided with reservoirs and orifices appropriate to the number of fluids to be dispensed. The signals from the control electronics determine which fluids are jetted, the number of drops of each fluid being jetted and the timing of jetting of the various fluids. This information is either programmed in the control electronics or downloaded from another intelligent system. 
     Low mass heaters are an important aspect of the apparatus because they allow quick evaporation of volatile fluids to generate enough vapor to produce the desired odor sensation and just as quickly cool off to stop it when the heater is used as a target medium. Another characteristic of heaters for this invention is that they do not produce an odor when heated. This is both critical and difficult to achieve. In addition, the target surface of a heater must allow wetting so that droplets do not bounce off the surface but wet it instead. A ceramic cement which wetted well, had no odor of its own after a little bum in time and withstood the heat is available through Cotronics Corp., Brooklyn, N.Y. identified as Durapot 801 is rated to 1650° C. The cement desirably enhances surface roughness of the heater which greatly improves wettability. It is also contemplated that surface roughness to improve wetting could be provided to the heating surface of the heater (impact surface) by such means as sand blasting, wire brush, sanding, ablation or other forms of abrasion. 
     Two types of heaters that worked well are surface mount resistors and thin film devices including platinum resistance temperature devices (RTD&#39;s). Surface mount resistors are rugged, inexpensive and readily available in a wide range of resistance values. Experimentation will readily determine the best resistance value for a particular temperature. If temperature control is desired, the RTD&#39;s are preferred. They are available through Omega Engineering, Stamford, Connecticut as part number TFD. Any of their thin film devices are useable. TFD&#39;s which had a resistance of 100 ohms and range of 100 volts D.C. were operated around 24 volts. Using RTD&#39;s at temperatures above the melting point of solder is possible as the leads are attached to allow temperature of 550° C. The temperature to evaporate phenethyl alcohol, for instance, was around 240° C. This is a useful solvent for fragrance dispensing. 
     To implement temperature control, a temperature sensor is best used with the heater. A preferred arrangement is the combination of two TFD;s or similar RFD;s mounted back to back with a high temperature silicone rubber cement. One RTD is then used as a heater while the other is used to sense temperature for feedback to the system controller in a rugged compact arrangement. If the temperature to be used to evaporate droplets is low enough, then the heater RTD may be replaced with a surface mount resistor at a significant cost savings. Other means to generate heat are contemplated including wire resistance heaters, laser radiation, etc. 
     FIG. 8 schematically shows another configuration of a fragrance ejecting device  136  in housing  137  which may include air inlet  139 . Most of the elements are the same as those of device  106  from FIG.  7 . Discussion of the common elements will not be repeated. Printhead  108  differs in this embodiment in that it includes an electrical interconnect  138  on the bottom of the printhead and the drive electronics  120  have been located in the different position. A significant difference in the construction of device  136  is the presence of a target medium  140  which intercepts droplets  110  as they are directed toward outlet  134 . Target medium  140  in this instance is preferably a permeable medium suitable for disbursing the volatiles, for which an exemplary material may be cloth. Other materials such as a fine wire mesh or perforated metal or ceramic disk might be conducive to providing a heating means for the target medium. Blower  126  is an air movement device mounted in a housing  142  containing a heating element  144 . This assembly warms and heats the air being moved which together with the vapor produced by evaporation of drops  110  proceed through target medium  140  to air-flow outlet  134 . In another embodiment, target medium  140  itself could comprise the air-flow outlet by removal of the portions of the housing that extend beyond it or it could be moved flush against the opening  134  where grating  134  is now present. Still further, the printhead itself could be separately heated to raise the vapor pressure of the fragrance or fragrances being dispensed. FIGS. 7 and 8 are but two examples of fragrance ejecting devices based upon the principle of the invention. One skilled in the art can understand that these basic elements can be combined in further different ways and in different shapes and combinations to create additional and different fragrant ejecting devices for other applications. 
     FIG. 9 schematically illustrates the type of printhead  36  illustrated in FIG. 3 mounted on a support structure  146  which shields the heater  150  and can be used to mount the printhead. The electrical interconnect substrate  42  is shown on the opposite side of printhead from the support structure. Solder joints or leads  148  would be used to electrically mount the printhead assembly. Heater  150  is attached to the side of the printhead. 
     FIG. 10 shows a small fragrance ejection device  152  mounted on a microphone support arm  154  having a microphone  156  supported on stand  158 . An electrical cable  160  is used to attach microphone  156  and ejection device  152  to a computer  162 . Computer  162  is conventionally attached to a keyboard  164  and monitor  166 . Microfabrication technologies allows for very small fragrance ejection devices to be built. Although the input device is shown to be keyboard  164 , one skilled in the art would recognize that other types of communication methods could be used, such as voice recognition, touch screen, remote cellular means, etc. Future video games and virtual reality systems could benefit from a fragrance ejection device, which adds one more human sense to the experience. Ejection device  152  could contain a printhead such as printhead  36 ,  58  and some or all of the components of the embodiment of FIGS. 7 and 8. 
     The system of FIG. 10 is continued in FIG.  11 . FIG. 11 illustrates a method of synthesizing a custom aroma, in this case involving the possible combination of eleven different fragrances displayed on monitor  166 . A multiple fluid printhead  152  is provided having a plurality of electronically operated fluid droplet ejection channels and a fluid supply reservoir for each channel. Computer  162  is programmed to operably drive the electronics connected to printhead  152  and selectively operate the ejection channels at a selected rate to eject droplets into a testing space which in this case may be the outlet  168  of device  152 . The multiple fluid supply reservoirs are supplied with each of the desired ingredients shown on monitor  166 , or some other combination. Software is provided to operate the selected fluid ejection devices according to the adjustable settings shown on the monitor. Droplet rate production is displayed on monitor  166  along with a percentage indicative of the relative amounts of the different ingredients. The operator can create a desired aroma for personal use or develop a custom aroma in real time by adjusting the settings and ingredients which are selected. Ejection device  152  does not have to be installed on the microphone as illustrated, but instead may be a separate unit presenting ejected droplets in a testing space which may have an opening for a target surface such as a card. Droplets deposited on the card when withdrawn can be sensed by the human nose. The application illustrated on monitor  166  in FIG. 11 actually comes from a famous Paris perfume composition. 
     FIG. 12 is a high level flowchart for the custom synthesizing system illustrated in FIGS. 10 and 11. This system includes a plurality of fragrance ejection devices  152  each of which has a reservoir which is loaded with a natural or artificial fragrance producing volatile fluid component such as the components listed in FIG.  11 . Depending upon the material, they may be neat fluids or dissolved or diluted with a commonly used alcohol composition which has no perceptible odor. The system is initialized in block  230  to identify ejection devices a-n in block  232 . The unit is powered up and heaters, if any are used, may be activated. The user inputs the identity or a code representing the identity for the fluid put in the fluid reservoir of each of the devices a-n in block  234 . The program tests each device a-n in block groups  236  and  238  to determine according to the instructions provided in block  234  whether a particular device A, B, C, etc. has been loaded with fluid a-n. If it is determined that a particular fluid is loaded in a particular device, the operating settings for operating the ejection device are recalled and made ready for use in group blocks  240  and  242 . These settings would include the pulse parameters and frequency for operating each ejection device a-n. The settings are applied to the drive for devices a-n in block  244 . Heaters, if used, would also be set here according to the requirements of the particular fluid. Next adjustment bars are display in block  246  on monitor  166 . The user inputs adjustments to the settings for the active devices in block  248 . Moving the selection bars changes the frequency and/or voltage to be applied to the ejection devices and some measure of the relative amounts that will be dispensed is presented to the user on the screen on the form of the number of drops per second and/or the relative percentage compared to the other fragrance components. In block  250  the devices are operated at the adjusted setting and fragrance tested either by means of the human nose or an electronic chemical sensor (electronic nose) in block  252 . Some indication of the fact that dispensing is underway is preferably indicated. If the fragrance produced is satisfactory, the system redisplays the adjustment bars and actual relative amounts dispensed in blocks  254  and  256  so that the user will get feedback as to the final mix. If the fragrance is not satisfactory, the system returns to block  246  and the process continues until a satisfactory fragrance is obtained or the system is shut down. 
     FIGS. 13 and 14 illustrate another application of fragrance ejection devices mounted in the housing of microphone  176 . A support band  174  having brackets  172  carry earphones  170 . FIG. 13 schematically illustrates the contents of microphone element  176 . In addition to microphone  178  are two fluid ejection devices  180  which are multiple ejection devices having multiple fluid reservoirs  182 . Heaters  184  serve as a target medium for multiple orifices  186  of devices  180 . The power supply, controllers and communication system, if any, are not shown and would preferably be externally connected through wires to devices  180 . Such a system could be useful in video gaming or a virtually reality headset whereby ejection of a relevant aroma (smoke, gunpowder, rain, etc.) could be initiated and terminated at different points in the program. The microminiaturization of these devices makes it possible to put a large number of them in a small space ideally suited for such simulations heretofore impossible. For example, virtual reality is illustrated in FIG. 15 where a person  188  wears a helmet  190  containing a virtual reality vision system  192  and a sound system (not shown). The fragrance ejection system  194  is mounted inside an adjustable arm  196 . A cloud  198  of fragrance has just been ejected. 
     FIGS. 16 and 17 represent the components of a fragrance dispensing stand  260  comprising a base  262  having support brackets  264  which support hollow tube  266  on base  262 . Blower  268  is mounted on the base in cooperation with a series of openings for air  270 . The blower and bracket would be provided with a cover (not shown). In the upper end  272  of tube  266  is a fluid ejection device assembly  274  mounted in spaced arrangement within upper end  272  including a hood  276  which covers the device  274  and has an opening for the emission of air moved past the ejection device. 
     FIG. 17 is an enlarged view of ejection device assembly  274  which includes a jetting device  278  made integral with a fluid reservoir and mounted in a base block  280  which has an opening for leads  282  which are used to operate the ejection device. The drive electronics and controller could be remotely located and are not shown in this case. An inner spacer  284  and an outer spacer  286  support ejection device  278  on base block  280 . A collar  288  supports a target medium  290  comprising a heater having a lead  292 . An endplate  294  completes the assembly. This provides an integral unit of very small size which is easily hidden in structures and driven by remote control or through wires that cannot be seen. For example, the device could be surrounded by a bouquet of artificial flowers to create an aroma by operating steadily or intermittently when a light switch is turned on or a motion sensor is activated. Despite the small size, the ejection device  278  can self-contain a large enough quantity of volatile fragrance containing fluid to last a number of months without refilling. The relatively inexpensive cartridge  278  can be removably replaced as a unit much like ink jet printer cartridges. 
     An exemplary jetting device  278  is illustrated in FIG.  18 . Jetting device  278  preferably has a hollow cylindrical PZT core  296  which is intimately plated on the inside with a metallic conductor  298 . It is intimately plated on the outside with a metallic conductor  300 . The front of PZT tube  296  is closed by means of about a 0.002 thick disk of nickel alloy electroformed with a centralized about 50 micron opening and soldered to the end of the tube in contact with metallic conductor  298 . The PZT tube may have an external diameter of about 0.075 inch O.D. with about a 0.05 inch I.D., which makes a very small device. Of course, the relative sizes may be scaled up preferably retaining a 50-60 micron opening  304 . The interior  306  is a chamber which can be filled with a fluid through a connection  308  connecting a tube  310  leading to a fluid reservoir. It is also contemplated that the back end of PZT core tube  296  can be partially closed after filling the tube with a finite amount of volatile fluid to be ejected. That is, it can be a self-contained device. 
     FIG. 19 is an alternate form of the dispensing stand illustrated in FIGS. 16 and 17 with an alternate head  312  which attaches to the upper end portion  272  of tube  266  or a smaller solid tube since no air passageway is required in this embodiment. Head  312  has a base  314  and a cover  316  having an opening in front  318 . On a support plate  320  is mounted a plurality of ejection devices  278  each having an orifice aimed at a controllable heater  322 . Of course, the number of these tiny ejection devices  278  and their corresponding accompanying heaters  322  could be greater in number than those shown. Air is drawn in through the openings  270  and the vaporized volatile material ejected from the jetting devices  278  or some combination of them passes through the outlet opening  318 . 
     Other examples of the application of what may be referred to as “smell jets” which could dispense aromas, fragrances and vapors include computers with an attached or separate aroma box or headset; radio or television sets; automobiles, pagers or telephones; home appliances such as stand alone air fresheners, smoke detectors or artificial flowers; personal items such as eyeglasses, broaches or pocket units; and medical instruments or devices. A particular advantage of the fragrance ejection devices of the invention is the fact that they are easily battery powered and due to the advancement of wireless technology, can be operated by very small commercially available wireless communication devices which can receive wireless signals that could turn the ejection devices on and determine their operating rate, sequence of operations and operating frequency. 
     FIG. 20 illustrates the sensory impact produced by the dispensing of ten drops fast in the upper graph  200  or ten drops slowly in the lower graph  210 . (It should be noted that the vapor concentration increases toward the bottom of the page.) From the baseline, the vapor concentration increases very rapidly when the drops are distributed rapidly so the intensity is greater. In the lower graph, the intensity is less but the sensory experience is extended over a much longer period of time. This is one of the key advantages of this type of fragrance ejection device; the ability to vary the rate of change to impact the sensation produced by the fragrance. 
     FIG. 21 schematically illustrates a similar type of experiment where ejection devices  212 ,  214  and  216  are denominated to produce fragrances A, B and C which are deposited upon a target surface  218  within an air flow passageway  220 . Air flow is shown by the direction of the arrows. The fragrance intensity as illustrated as measured by a conventional electronic chemical sensor commonly referred to as an “electronic nose”. This sensor produces a signal representative of the intensity. The fragrance intensity versus time is plotted below for each of the fragrances A, B and C. Curve  224  illustrates a slowly varying dispensing where the intensity of the fragrance A rises slowly and then after a time slowly declines. Curve  226  illustrates a rapid and regular change in the intensity level of the fragrance B. Curve  228  represents an intermediate level of fluctuation for fragrance C as compared to the curves for fragrances A and B. The varying results are produced in accordance with the quantum and rapidity of droplet ejection. One skilled in the art can understand that the number of fragrances could be expanded many times beyond that of three fragrances and the resulting fragrance could be produced as a combined fragrance by operating selected ones of the fragrance jets as indicated previously. 
     FIG. 22 is an actual graph of data taken from operation of the printhead like those shown in FIGS. 2,  3  and  4 . A regular increase in drop size and velocity is observed jetting isopropyl alcohol at a droplet rate of 2000 droplets per second as the voltage is increased from eight to fourteen volts. Droplet size is shown in picoliters and velocity is measured in meters per second. A similar non-odor producing alcohol is commonly used as a solvent or diluent for fragrances although is it not the only solvent that may be used. 
     In an alternate embodiment, the invention can be used in combination with electronic chemical sensors which are increasing referred to in literature as “electronic noses”. Electronic noses are discussed in some detail in the following references which are incorporated herein by reference. Baletz, Lange, and Koll, “The Electronic Nose in Lilliput”, IEEE Spectrum, pp. 36-38, September 1998 and Kaplan and Braham, “The How and Why of Electronic Noses”, IEEE Spectrum, pp. 22-34, September 1998. The former of these mentions an experimental electronic nose that could easily fit in a wristwatch. The invention provides a means for real time calibration of electronic chemical sensor arrays used in electronic noses which are capable of analyzing complex odors and vapors. Electronic noses work by comparing process signals from a sensor array with known patterns stored in a data base. 
     Various types of sensor arrays which are possible include conductive polymer sensors (U.S. Pat. Nos. 5,801,297; 5,145,645; 4,911,892; and 5,756,879), metal oxide conductivity sensors (U.S. Pat. No. 5,777,207), quartz resonator type sensors (U.S. Pat. No. 5,177,994), polymer dielectric sensors (capacitor), fluorescent optical sensors, etc. The type of sensor will determine the key features: number of sensor elements, detector sensitivity (threshold and response curve), stability, reproducability, response time and refresh time. The above mentioned U.S. patents are incorporated herein by reference. 
     The weaknesses of the present technology which this invention helps to overcome are the fact that electronic chemical sensors drift with time, temperature and relative humidity which affect the accuracy of their measurements. Refresh time tends to be long because a new baseline needs to be established prior to the next measurement; purging and back-fill with an external gas supply is costly and leads to a slow response system; and, if the relative humidity of the gas sample being measured is different from the calibration gas, then measurement errors will exist. 
     The invention is based upon the concept that a jetting device or ejecting device would dispense droplets of a calibration fluid onto a heated wick (target medium) in a passageway where a controlled airflow carries the calibration gas vapor over a sensor or array of sensors. Previous calibration of the ink-jet type ejection device establishes the number of calibration vapor molecules per cubic centimeter being delivered at the sensor site. By changing the number of drops, droplet size or the droplet rate, the molecular density could be increased or decreased. Naturally the calibration gas and vapor should be selected to be of the same character or even the same material itself which the sensor is intended to measure. In the sense that we are talking about an odor producing material being measured by the sensor, we are referring to volatile organic chemicals (VOC&#39;s) which are dispersed as vapor in the air or some environmental gas. 
     FIG. 23 is a schematic representation which illustrates the use of a microjet calibration system  324  which is located in a flow passage  326  which has additional inlets (ports) for odor producing volatile materials which are identified as VOCs  328  and purge gas  330 . There is an inlet for a purge gas supply  330  with the gases all moving in the direction of the arrows in FIG.  23 . Valves of some sort would be used to control the gas flow and to shut off any one of the inlets from items  324 ,  328 ,  330  so that the effect of one of them on the sensors  348  can be determined. System controller  356  opens and closes the inlet ports with valves (not shown). 
     FIG. 24 schematically represents ejection device  332  which is preferably a piezoelectric device such as described previously herein. Device  332  has an ejection orifice  334  and ejects droplets taken from a fluid reservoir  335  onto a preferably heated target medium  336  where the drops are volatilized to create a calibration gas. An air movement device such as a fan  338  in FIG.  23  and/or the opening  340  of the inlet into which the ejection device is directed are configured so that the concentration of calibration gas which is moving through housing  342  is carefully controlled and uniform. By evaporating a known volumetric amount of calibration fluid microdroplets  344  in a known flow of air or other environmental gas, an exact concentration of a calibration fluid can be repeatedly obtained. The beauty of the system is that it is nearly instantaneous since the droplet production can be started and stopped and operated at a precisely controlled rate by means of electronic signals controlled by a programmed system controller  356  together with drive electronics (not shown) as illustrated in the previous embodiments. 
     A sensor array  346  having a plurality of sensors  348  is positioned with respect to housing  342  to pass either calibration gas, purge gas or an unknown gas containing VOC&#39;s over the sensor array which may be referred to herein as “sensor”. Raw signals from the sensor are transmitted to a digital signal processing unit  348  to identify the gas being exposed to the sensor. The signal processing unit is connected to a pattern recognition unit  350  which takes the processed signals from the signal processing unit and performs a number of operations. It is connected to database  352  containing key feature information for a large number of odors and vapors which are possible unknown VOCs. It sorts the data into key features and then compares the VOC features to information from either the microjet calibration system or the data base  352  of odors and vapors or both. System controller  356  controls a number of functions. It controls the gas handling system and fan  338  together with the microjet calibration system  324  and operates valves (not shown) which allow access to housing  342 . It communicates with the signal processing unit and the pattern recognition unit which locates data from the database and communicates the information to the pattern recognition unit. It should be noted that with today&#39;s integrated circuit technology, one device could do the functions of several. For example, the signal processing unit, the pattern recognition unit, the memory for the data base and the system controller could all be built into one microprocessor-type unit. 
     The calibration signal produced by the sensor in response to a known concentration of calibration gas allows one to determine the sensor response to a like molecule and remove the background drift caused by relative humidity changes, temperature changes and use history. It is also useful to determine the threshold for sensors to specific molecules. For example, by increasing the known concentration of calibration gas in steps, it can be determined when a particular sensor reaches a detection threshold for that gas. The calibration fluid concentration preferably contains volatilized microdroplets from the same odor producing material to be sensed or a like-molecule. Because the individual microdroplets  344  are reproducible nearly exactly the same, we have the ability to predetermine the number of molecules per droplet in order to determine the concentration per unit volume. Although only one ejection device is schematically illustrated in FIGS. 23 and 24, it is understood that a plurality of ejection devices using printheads similar to FIGS. 2,  3 ,  4  and  5  can introduce a known concentration of multiple different calibration fluids to map additional sensors or accurately map the response of one sensor. The purge capability provided by purge gas unit  330  allows for determination of a baseline at a specific relative humidity. It also allows study of the optimum refresh cycle of the sensor array in cooperation with the microjet calibration system. After the response of the sensor array to introduction of VOC&#39;s  328  is performed, the VOC port can be closed by the system controller and the purge gas introduced to reverse the effect of the VOC&#39;s on the sensors in readiness for recalibration. The entry port to the purge gas is closed and the inlet port for the microjet calibration device is opened to operate device  334  to obtain a real time calibration. Then the calibration gas port is closed and the port from the VOC gas to be measured is opened whereby the baseline response of the sensors to the calibration gas may be used to adjust the value measured by the sensor from exposure to the unknown VOC&#39;s to produce a corrected result. A further indication of these characteristics are represented by reference to FIGS. 25-27. 
     An alternate location for sensor  346  denominated sensor  347  containing a single or a plurality of individual sensing elements  348  is shown in FIG.  24 . In this arrangement the sensor is located in close proximity to where the calibration gas is being generated. This is more like a static arrangement where the calibration gas and sensor could be placed in an enclosure which could be purged with air or other gas periodically and samples of unknown gas introduced periodically. Still further, the sensor could be mounted on an arm that is periodically placed into the enclosure for calibration and/or purging to refresh it prior to being reexposed to an unknown sample gas. 
     FIG. 25 indicates a signal produced by the sensor  346  plotted over time. The signal may drift as indicated because of the effect of factors mentioned previously. 
     FIG. 26 illustrates the signal from the sensors plotted over time with reference to the use of the microjet calibration system. The area  358  illustrates the off signal which may be indicative of the freshly purged sensor just before microjet calibration system  334  is turned on. Then calibration unit  334  is turned on at the rate of x drops per second to produce a response level  360  of the sensor  346  to a calibration gas of first concentration. This information will be stored by reference to the pattern recognition system and data base. Then calibration system  324  may be operated at an increased rate of x+y drops per second at  362  to generate a calibration gas of a second concentration which produces a response level  362 . This information is likewise processed and stored. The information in FIG. 26 is used to establish the baseline response  360  and  362  of the electronic chemical sensor  346  to calibration gasses of first and second concentrations. Additional response points could be generated to produce a response curve of the sensor to specific known gas concentrations in real time. Then when the sensor is immediately thereafter exposed to a flow of air containing an unknown concentration of odor producing material, the response can be compared with the calibrated response to establish a value for the unknown concentration. Because of the proximity in time of the measurement to the calibration, the effects of drift are taken into account in making the concentration determination of the unknown. It is also possible to use an ejection device of device  334  to inject controlled amounts of water which are vaporized to produce known amounts of water vapor corresponding to relative humidity and thereby produce a real time relative humidity response curve for sensor  346 . This can be combined with calibration gas results to generate a correction factor which can be applied later when sampling an unknown. 
     Finally, FIG. 27 is indicative of the signal produced by sensor  346  from a pre-exposure baseline level  364  to a higher level  366  representative of exposure to air flow which contains the unknown VOC&#39;s. Immediately after this exposure, the port to the VOC&#39;s can be closed and the purge gas introduced for a short time followed by closing of the port to the purge gas and recalibration with the microjet unit  334  to confirm the value obtained in the test. 
     Those skilled in the art will appreciate that various modifications to the method and apparatus of the present invention may be made without departing from the scope of invention as defined in the appended claims.