This invention relates to a pacifier assembly, and more particularly to an improved temperature-responsive pacifier assembly. This application is a continuation-in-part of United States Application, Serial No. 351,107, filed February 22, 1982.

Oral and rectal thermometers having a temperature range of from about 33°C to 41°C have been in use for many years for sensing the temperature of the human body. The use of oral thermometers with infants is particularly troublesome due to the difficulty of keeping such a thermometer in the baby's mouth under conditions and for a time sufficient to permit the inserted portion of the thermometer to reach ambient conditions therein, and thereby produce a reasonably accurate reading of the actual temperature of the subject being temperature sensed. Consequently, for newborns, rectal thermometers are generally used which are believed to cause discomfort, and again are somewhat difficult to use, although not as difficult as the use of oral thermometers.

Another form of temperature sensing devices is illustrated in U.S. Patent No. 4,296,631 to Fergason. In U.S. Patent No. 3,968,690 to Blouin et al, there is disclosed a pacifier assembly including a mercury thermometer device, however, the concomitant problem of glass and mecury are still present.

As infants age with concomitant cutting of teeth, the use of an oral thermometer becomes hazardous due to the possibility of breakage as well as greater awareness by the subjects to the foreign object. Generally, the use of a thermometer is to generate data as to the existence of abnormal temperature, i.e., a temperature above 37°C, and not necessarily the number of °C above normal temperature to permit the institution of a corrective protocol for the subject exhibitinq an above normal temperature. The use of a thermometer for a subject is generally initiated based upon observable side effects of an abnormal temperature, e.g. skin color, respiration, etc. as distinguished from any constantly observable or recognized phenomena.

In the aforementioned co-pending application U.S. Serial No. 351,107, here is disclosed a pacifier assembly including a spherical capsule of a liquid crystal material submerged in a liquid medum, such as glycerine, in the interior bulbous chamber of the pacifier assembly. The liquid crystal material is responsive to a temperature above about 37°C whereby the liquid crystal material changes color to visually indicate abnormal temperature condition of a mammal, and in particular a homo sa^pien, utilizing such a pacifier assembly. Since the spherical capsule is essentially free flowing within the chamber, the pacifier assembly may not accurately and rapidly sense an abnormal condition depending upon the relative position of the spherical capsule with in the pacifier assembly to the mammal during use. F.g., if the mammal is standing up-right and the pacifier assembly extends downwardly concomitant with intermediate use, the spherical capsule tends to be point positioned proximate the guard and thus the heat transfer rate of the liquid medum might not be sufficient to cause the liquid crystal material to clear under discontiniuous conditions of use.

It is an object of the present invention to provide an improved temperature-response pacifier assembly for sensing an above normal temperature of a mammal, and in particular, a homo sapien.

This object is achieved by a pacifier assembly having a liquid medium disposed in an interior chamber, and a temperature-responsive element comprised of a spacer strip or element having one or more temperature display dots mounted thereon and formed of a liquid crystal material coated on a colored substrate. The liquid crystal material is responsive to a temperature above about 37°C whereby the liquid crystal material clears to expose the colored substrate thereby visually indicating an abnormal temperature condition of a mammal, and in particular, a homo sapien, orally utilizing such improved pacifier assembly. The temperature-responsive pacifier assembly according to the invention for sensing an above normal temperature of a mammal permits more efficacious sensing. The temperature-responsive pacifier assembly according to the invention also permits a more responsively sensing of an above normal temperature of a mammal. A further advantage of the present invention resides in sensing an above normal temperature of a mammal exhibiting greater visual display of such above normal temperature condition.

A better understanding of the present invention as well as other objects and advantages thereof will become apparent upon consideration of the detailed disclosure thereof, especially when taken with the accompanying drawing, wherein

• FIGURE 1 is an elevational view of the improved pacifier assembly of the present invention; and
• FIGURE 2 is a cross-sectional view taken along the lines 2-2 of FIGURE 1.

Referring now to FIGURES 1 and 2, there is illustrated a temperature sensing pacifier assembly, generally molded in one piece and generally indicated as 10, comprised of a bulb or nipple portion, a preventing guard portion and a handle portion, generally indicated as 12,14 and 16, respectively. The pacifier assembly 10 of the present invention is formed of a non-toxic elastomeric material, such as a foodgrade transparent plasticized polyvinyl chloride or synthetic transparent rubber, or the like.

The nipple portion 12 is defined by an external bulbous surface 18 and is formed with an interior chamber 20 defined by an interior surface 22 with an orifice 24 in the guard portion 14 providing access to the interior chamber 20 thereof. In the interior chamber 20 of the nipple portion 12, there is provided a temperature responsive element 26 comprised of a rectangularly-shaped transparent thermoplastic strip 28, such as formed of rigid , on which is mounted one or more temperature display dots, generally is indicated as 30, comprised of a liquid crystal material 32 coated on pre-select colored substrate 34. The temperature responsive element 26 is therefore positioned within the chamber 20 in an elastomeric compatible liquid 36, as hereinafter more fully described.

The temperature display dots 30 are preferably mounted on end surface portions of the thermoplastic strip 28 with the thermoplastic strip 26 being preferably formed of a clear thermoplastic material. The temperature responsive element 26 is positioned with in the chamber 20 of the nipple portion 12 of the temperature-responsive pacifier assembly 10 in a manner to position the temperature display dots 30 proximate the end of the nipple portion 12 opposite the guard portion 14. In this manner, insertion into the oral cavity of a mammal permits positioning of the temperature display dots more deeply within the oral cavity whereby heat transfer between the oral cavity and the temperature display dots 30 permits of a more rapid response period to an above normal temperature conditions of the mammal.

The temperature response element 26 disposed in the elastomeric compatible liquid 36 is sealed, such as by an adhesive, ultrasonics, radio frequency or the like, within the chamber 20 of the pacifier assembly 10 by a food grade elastomeric material, such a plasticized vinyl chloride plug 38 an elastomeric material for the pacifier assembly 10 as well as the plug 38 is dicated by the desirability of durability to substantially eliminate direct shearing conditions under which the outer surface 13 of the nipple portion 12 of the pacifier assembly 10 may be subjected against the capsule, particularly during teething of a using individual.

Liquid crystals are well known to one skilled in the art. Liquid crystals materials formulations displaying a color change above 37°C, and preferably at a temperature above about 37,8°C _! 0,14°C is preferred as being representative of a temperature through which a positive identification may be made that a feverous condition exists above the normal body temperature of 37°C. This minimizes a reaction by an observer to an actual 37°C normal condition a temperature of 37,8°C of the mammal would more fully result in positive corrective steps, or at least further testing.

Cholesteric liquid crystals are preferred since such cholesteric liquid crystals are non-toxic and readily passed through the body if accidentally ingested by the pacifier user. Example of an cholesteric liquid crystal exhibiting a color change display at 37,8°C is a mixture of p-n-Pentylphenyl-p-methoxybenzoate (PPMEOB) and p-n-Pentylphenyl-p-n-pentylbenzoate (PPPEB). Other cholestric liquid crystal materials exhibiting like display temperatures are disclosed in the aforementioned United States Letters Patent to Fergason.

Generally, cholesteric liquid crystals exhibit an iridescence color at temperatures below the response or clearing temperature, e.g. a bright green irridescent color is visually exhibited by a cholesteric liquid crystal material comprised of a mixture of p-n-Pentylphenyl-p-methoxybenzoate (PPMEOB) and p-n-Pentylphenyl-p-n-pentyl- phenzoate (PPPEB) exhibiting a clearing temperature at 37,8°C - 0,14°C. Thus, in the instant invention such a liquid crystal material 32 provides a bright green iridescence and when coated on a black substrate 34 will result in a change in the color appearance from.a-bright green to black of the temperature responsive dot 26, when a temperature of 37°C has been exceeded readily visually identifiable by an observer.

The elastomeric compatiable liquids are thermally conductive, such as glycerine, a fluid which does not de-plasticize the plasticized polyvinyl chloride when compared to most vegetable and mineral oils. The use of such vegetables and mineral oils is not desired since such oils dissolve the plasticized materials thereby permitting the nipple assembly to become tough and rigid over short periods of time. Glycerine, not being an oil does not de-plasticize the polyvinyl chloride composition forming the nipple assembly 10 and is compatible with the materials forming the temperature responsive element 26. A bitter additive, such as quinine or the like, is added to the elastomeric compatible liquid. Should a child accidently rupture the fluid filled cavity of the pacifier, quinine or the like additive causes the unit to reject the damaged pacifier.

The pacifier assembly 10 may be formed in a like manner as that of the aforementioned copending application, i.e. after positioning of the temperature responsive element 26 and addition of an appropriate elastomeric compatiable liquid 36, the pacifier assembly 10 is then sealed with a clear PVC cement which is allowed to form a permeating miniscus type geometry at the pre-filled pacifier orifice 24, such a PVC cement being of a composition similar to the pacifier assembly 10. The thus formed temperature sensitive pacifier assembly 10 is maintained in the hereinabove described position for a period of at least about 12 hours prior to bulk packaging.

Once the pacifier assembly 10 of the present invention changes color indicating an abnormal temperature level as a result of use by an individual, resort to a mercurial thermometer is generally contemplated as part of a use protocol of the instant invention. Once removed from the mouth of a user, the liquid crystal material will resume its initial color after a predetermined time period at ambient room temperature.

While the present invention has been described with a liquid crystal materials displaying color change temperature level of 37°C, preferably of 37,8°C - 0,14°C, it will be understood by one skilled in the art that slight variations may be made to such color change temperature level. One skilled in the art will appreciate that the composition of the liquid crystal may be formulated to effect different color changes other than the above described green to black.

Generally, liquid crystal materials displaying the desired color changing protocol herein described generally are adversely effected by the elastomeric material of the pacifier and thus cannot be formulated, per se, in the elastomeric material of the pacifier assembly although some liquid crystals may exist which may be included in such a formulation. Microencapsulation of the liquid crystal materials, as distinguished from macroencapsulation, as herein described, would permit formulation with the elastomeric material, particularly for molding the nipple portion of the pacifier assembly thereby providing a more efficacious process for forming such temperature responsive pacifier assemblies.

Numerous modifications and variations of the invention are possible in light of the above teachings and therefore the invention may be practiced otherwise than as particularly described.