Abstract:
An adjustable and economical finger stylus useful in operating a touch sensitive screen and for entering data in, e.g., a personal data assistant (PDA). The adjustable elements of the finger stylus provide for rapid, convenient and significant adjustability while comfortably securing the stylus to the finger during use. Once sized, the stylus can readily be slipped on and off the user&#39;s finger as needed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims benefit of U.S. Provisional Application No. 60/211,370, filed Jun. 14, 2000, and is a divisional of application Ser. No. 09/879,507, filed Jun. 12, 2001, the disclosures of which are hereby incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a stylus tool for use with touch-sensitive electronic screens such as a personal data assistant (“PDA”) as well as other computer and data entry equipment. Typically, a PDA is portable and includes functions that permit it to perform as a computerized personal organizer. It utilizes a pen-like stylus in combination with a computerized touch screen for inputting data. The writing end or tip of the stylus allows the user to point and touch, as well as to write individual letters and numbers into an input field on the PDA without the use of a pen, pencil or other type of marking instrument. 
     A typical first generation PDA allowed users to carry a small battery operated computer device to keep addresses, maintain a scheduling calendar, perform calculator functions, and keep a “to-do” list. Second generation PDAs include such further features as access to the Internet, functioning as a cellular telephone, performing complex computer functions such as spreadsheet applications and other computer software, and playing digital music. The potential for these portable and lightweight devices is expanding and future developments are said to include video cameras, video cellular telephones, digital cameras, garage and television remote controls, etc. 
     A PDA is typically designed to include a holder for a pen-like stylus that can be removed for use from an opening in the PDA housing. However, the pen-like stylus is subject to being lost, e.g., when the user forgets to replace it in the housing, and a replacement stylus must be obtained. It is preferable that a replacement stylus, or the original equipment stylus, be inexpensive, compact, portable, comfortable and easy to use, so that a user can own several, and carry one or more for convenience. The improvement required is a stylus that is compact, inexpensive, comfortable and easy to use. 
     The typical stylus currently available commercially for use with a PDA is a smooth tipped pen-like device designed to be held in the hand as one would hold a pen or pencil. It allows a user to input data by touching an interactive screen, pointing, and/or writing numbers and letters. Typically, a PDA computer device includes such a writing stylus. Additionally, after-market variations of the pen-like design also have been marketed. 
     Also available is a type of finger stylus. For example, one such “finger-tip stylus” has been advertised for sale on the Internet by Concept Kitchen, Inc. This device is made of easily bendable metal and is designed to fit over the top of the finger tip. It includes two tabs that are bent down so as to squeeze against the sides of the finger tip in order to secure the device to the finger. Since the tabs are easily bent, subsequent use or storage, e.g., when carried in the user&#39;s pocket or purse, subjects the tabs to inadvertent bending, leading to a need to resize it upon each use. Eventually, the tabs are subject to breaking from repeated bending. 
     U.S. Pat. No. 2,921,590 discloses a disposable and dispensable tooth brush that can be attached via adhesive strips to the base of a finger, wherein the bristles are disposed on the base of the device corresponding to the lower, or fingerprint surface of the finger. 
     U.S. Pat. No. 4,738,556 discloses a finger-mounted ball point pen incorporating various padding elements for the comfort of the user. It also discloses the use of a large strap element including hook and loop material for securing the device to the finger by wrapping around a substantial portion of the user&#39;s finger. 
     U.S. Design Pat. No. D418,494 illustrates a split ring design for a finger-tip stylus. The split ring shaped portion is required to flex in order to meet the variations in human index finger size. Such an arrangement is limited in that a small index finger is fit too loosely, rendering the product useless as a writing stylus, whereas a large index finger is unduly pressured, making the user uncomfortable. Additionally, the illustrated structure results in the user&#39;s cuticle and fingernail being covered, making it uncomfortable during long periods of use. Furthermore, a user having long fingernails, or even fingernails that protrude only slightly beyond the fleshy tip of the finger will be uncomfortable or unable to use this type of fingertip stylus structure. 
     U.S. Pat. No. 6,075,189 also employs a split ring member to attach a finger stylus and is subject to the same limitations discussed above with regard to U.S. Pat. No. D418,494. In the &#39;189 patent the tip end is removable in order to facilitate the use of various size tip members. 
     Similar split ring structures can be found in U.S. Design Pat. Nos. D253,416; 246,904; 217,745; and 212,981; as well as in U.S. Pat. Nos. 4,127,338 and 5,885,018 that apply such a structure to a pen or pencil. Additionally, U.S. Pat. No. 1,444,982 applies the split ring structure to a pick for musical instruments. FIG. 2 of the &#39;982 patent is strikingly similar to the structure disclosed in U.S. Design Pat. No. D418,494 and FIG. 1 of U.S. Pat. No. 6,225,988. The latter patent, a continuation-in-part of U.S. Pat. No. 6,075,189 discussed above, also discloses a split ring structure. 
     U.S. Pat. No. 5,529,415 discloses a pen which is attached to a shroud-like finger tip portion that fits completely over the finger tip and is incapable of size adjustment. A similar structure is disclosed in U.S. Pat. No. 5,453,759 that also incorporates electronic components in the tip member for use in interacting with a computer system. 
     Japanese patent abstract publication number 11134103A discloses a split ring finger stylus designed to fit on the top surface of the finger. It includes an extension or pointing element attached to the top surface of the ring for touching a computer screen. 
     Further improvements for fingertip styli are required to improve their universal fit at a reasonable cost, while simultaneously improving comfort and portability. 
     SUMMARY OF THE INVENTION 
     An adjustable finger stylus comprising: (a) a longitudinal element parallel to and in touching contact along a lower surface portion of the length of the finger extending back from the tip of the finger, wherein the longitudinal element curves upwardly from the lower portion adjacent the finger tip end and terminates proximate the finger nail; (b) the longitudinal element including at least one adjustable finger engaging element integral the longitudinal element and extending outwardly therefrom in order to secure the stylus to the finger; and (c) a tapered writing extension extending longitudinally from the end of the curved element and forward the finger nail. 
     In a preferred embodiment, the adjustable finger engaging element comprises one arm extending outwardly from each side of the longitudinal element and including as engaging means either (1) hook or loop material or (2) studs or holes in each of the arms so that when the arms are wrapped over the top of the finger in overlapping fashion and engaged, a ring-like structure is formed that secures the stylus to the finger. The use of hook and loop material or studs and holes provides for convenient and significant adjustability of the finger stylus while comfortably securing the stylus to the finger during use. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective side view of a preferred embodiment of the invention with two bands joined to form an overlapping ring-like structure suitable for engagement around a finger. 
     FIG. 2 is a side view of FIG.  1 . 
     FIG. 3 is a back elevational view of FIG. 1 with the bands disengaged. 
     FIG. 4 is a bottom view of FIG.  3 . 
     FIG. 5 is a front view of FIG.  3 . 
     FIG. 6 is a perspective side view of an alternative preferred embodiment of the invention with a single band forming a ring-like structure suitable for engagement around a finger. 
     FIG. 7 is a side view of FIG.  6 . 
     FIG. 8 is a back elevational view of FIG. 6 with the single band disengaged. 
     FIG. 9 is a bottom view of FIG.  8 . 
     FIG. 10 is a front view of FIG.  8 . 
     FIGS. 11A-F is a front view of FIG. 3 illustrating alternative structures for linking two finger engaging elements to one another. 
     FIGS. 12A-F is a front view of FIG. 8 illustrating alternative structures for linking a single finger engaging element to the stylus. 
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings, a preferred embodiment of the adjustable finger stylus of the present invention is illustrated and generally indicated in FIGS. 1-6. The stylus tip, located at  10  in all figures, is used for “writing” or inputting information via a touch screen, e.g., as employed in combination with a PDA or other electronic computer device. The tip preferably has a smooth rounded end that is compatible with such touch sensitive screens. 
     The stylus tip is preferably attached to the front end of a substantially rigid curved element located at  11  in all figures. For purposes of the present invention, “substantially rigid” denotes that the identified element, while rigid, is capable of some flexibility if grasped and manually flexed, but it is sufficiently rigid so as to permit touch screen operation without undue bending of the stylus tip and/or the element to which such tip is attached, where such undue bending would interfere with its convenient use as a stylus. In use, the user&#39;s finger to which the stylus is to be attached, e.g., the index finger, is placed onto the upper surface of  12  (as illustrated in FIG. 3) so that the tip end of the index finger is in proximate touching contact with the inside curve  11  as more clearly shown in FIG.  3 . The curvature of  11  facilitates comfortable contact of the stylus to the finger. Located at  18  in FIG. 3 are ridges that protrude from the inner radius of the curved surface of  11 . These ridges, which can be any type of protrusion, including vertical as illustrated, horizontal or at an angle to the vertical or horizontal, or a combination thereof, provide a gripping surface so that undesired movement, e.g., lateral movement, of the finger stylus is inhibited during writing or data input. The height of curved element  11  can be chosen to accommodate the flesh portion of a majority of the human population&#39;s index finger without interfering with a protruding fingernail. Preferably, the highest point at the end of element  11 , proximate the fingertip, is just below the fingernail. It is within the scope of this invention to adjust the curvature and rise of element  11  to suit specific population segments, e.g. children, teenagers, and adults, as well as those who may use the adjustable finger stylus with a gloved hand, e.g. nurses, paramedics, surgeons, etc. 
     Element  12  in each figure, extends along the length of a user&#39;s finger, and is also slightly curved, as illustrated, so as to comfortably wrap underneath and along the lower surface of a user&#39;s finger. The length of element  12  is not critical and can be selected so as to be comfortable for use with each of the population segments noted above, or of an average length suitable for a majority of the members of such groups. Preferably, the rearward end of  12  terminates prior to the second knuckle of the index finger (using as a reference or starting point the tip end of the finger); more preferably it terminates between the first and second knuckle. For example element  12  usefully can be from about 0.5 to about 1.0 inch long; preferably from about 0.6 to about 0.9 inches; more preferably from about 0.7 to about 0.8 inches; for example, about 0.75 inches long. The overall length of both elements  11  and  12  can be from about 1.2 to about 1.75 inches; preferably from about 1.25 to about 1.6 inches; more preferably from about 1.3 to about 1.5 inches; for example, about 1.375 inches in length. The thickness of element  12  is not critical provided that it is substantially rigid. Similarly, its width is not critical, but preferably it is sufficiently wide so that the finger rests comfortably in the concave region; for example, from about 0.2 to about 0.75 inches wide; preferably from about 0.25 to about 0.6 inches; more preferably from about 0.3 to about 0.5 inches; for example about 0.375 inches wide at the position where the engaging elements or side bands meet element  12 . Both  11  and  12  make up a substantially rigid element that preferably is curved in two dimensions, i.e., back-to-front, rising up at the front or finger tip end, and side-to-side forming a concave or bowl-like structure in which the lower surface of the finger is rested, as illustrated in FIGS. 1 and 3. As noted above, these combined elements of the stylus offer only limited flexibility, which is preferred in order to maintain accuracy in transferring the motion of the user&#39;s index finger to the end of the stylus tip when inputting information into a touch screen. 
     A band is preferably structured to include one or more areas of reduced transverse cross sectional thickness in order to function as a hinge point and facilitate bending of a side band to form a loop around the finger. Such areas of reduced cross section, or bending lines, are illustrated at  13  in the figures. In FIGS. 3,  4  and  5 , element  20  is shown with eight bending lines, whereas element  14  has two. Located at  19  in these figures is an optional transition area leading to a thinner region of element  14  to further improve flexibility. Selection of the number of bending lines and the use of a transition area depends on the thickness chosen for the side band and the stiffness of the material front which it is constructed. Using limited experimentation, one skilled in the art can readily determine whether to employ such features and, if so, the number and depth of such features. For example, if the band is sufficiently thin and the composition sufficiently flexible, it may be feasible to forgo the use of a bending line and/or a transitional area leading to a region of reduced thickness. 
     In order to facilitate attachment of the stylus to a finger (or, more accurately, to secure the stylus to a finger), extending laterally from at least one side of  12  is at least one side band or finger engaging element,  20 ; FIGS. 1-5 illustrate the use of two side bands, whereas FIGS. 6-10 illustrate the use of one such band. In use, the two side-band embodiment attaches the stylus to the finger by overlapping one of the bands over the other to form a ring structure, as illustrated in FIGS. 1 and 2. The side bands are fixed to one another by various linking or attachment means, selected from the group consisting of studs and receptor holes, material comprising hooks and loops, permanent or semi-permanent adhesive (the latter being of a type that is capable of holding the two surfaces together during engagement of the arms, but which can be readily pulled apart by hand and subsequently re-engaged if desired, e.g., of the type use on adhesively removable notepaper sold under the brand name Post-It®), buttons and holes, snap together elements (e.g., of the type found on clothing, including metal or plastic versions thereof), magnetic strips, angular ridges or teeth formed on and protruding from opposite faces of the engaging surfaces so as to interlock (permanently or temporarily) when engaged, etc. Hook and loop material is available commercially under the brand name Velcro®. Each of the hook and loop material may be added to the appropriate surface of each of the adjustable finger engaging elements as adhesive backed strips or each material may be made integral with the elements at the time of forming. The figures illustrate linking means according to the use of male studs and female receptor holes; as element  17  already engaged in FIG.  1  and FIG. 2 or, prior to engagement, as elements  15  (hole) and  16  (stud) in FIG. 4, FIG.  5  and FIG.  9 . However, it is to be understood that any suitable engagement means that secures the stylus to the finger is suitable, including, as discussed, hook and loop material. The methods or structures described above as useful for linking or attaching two side bands to one another, in addition to the use of studs and holes, are illustrated in FIGS. 11A-F as follows: A illustrates hooks at  16  and loops at  15 ; B illustrates adhesive layers at  15  and  16 , and, as described above, such layers can, in one instance comprise a semi-permanent adhesive and in another instance, a permanent adhesive; C illustrates buttons at  16  and holes at  15 ; D illustrates one component of snap elements at  16  and the other component at  15 ; E illustrates magnetic strip layers at  16  and  15 ; and F illustrates angled teeth and ridges at  16  and  15 . 
     When two bands or finger engaging elements are employed it is not necessary that each be the same length. In fact, it is preferred that in the case where studs and holes are used to link the bands, that the band containing the studs be shorter and contain fewer studs than there are corresponding holes. The use of a shorter band containing the studs can facilitate alignment of the studs with the holes when engaging the two bands. In contrast, differential band length may not be necessary when using hook and loop material since precise alignment is not required to effect engagement. Although FIGS. 4 and 5 illustrate the use of six studs it is to be understood that fewer studs can be used provided that secure engagement is achieved, e.g., as few as two studs can be used and the length of the band in which the studs are present can be reduced accordingly. Similarly, it may be convenient to include a greater number of studs that are spaced closer together and, correspondingly, more holes in the other band, in order to facilitate closer sizing of the stylus to the finger. When two bands are employed, the length of each of the finger engaging elements can be from about 0.75 to about 1.75 inches; preferably from about 0.8 to about 1.6 inches; more preferably from about 1.0 to about 1.5 inches; for example, from about 1.05 to about 1.45 inches. When different lengths are employed for the two bands, the difference can be conveniently selected. For example, it has been found that a difference of 0.375 inches is suitable. 
     The width of a finger engaging element or band is not critical, but it is preferred that it be no wider than the finger digit around which it is wrapped; preferably narrower than such digit; more preferably as wide as is necessary in order to receive the holes and studs, or hook and loop material, or other such engagement means as is employed in order to securely engage the stylus to the finger. For example, a band can be about 0.25 to about 0.5 inches wide; preferably about 0.28 to about 0.45 inches; more preferably about 0.33 to about 0.40 inches wide; for example about 0.375 inches wide. 
     When present, the bending hinges  13  and the thinned area  19  facilitate the motion illustrated at  21  in FIG. 3 to create a ring-like form, completed as illustrated in FIGS. 1,  2 ,  6  and  7 . Engagement of the stylus to the finger is accomplished by bending and rotating the side bands  20  up and over the top surface of the finger, preferably with the band containing the studs closest to the top surface of the finger, aligning studs with corresponding holes when the band is in close proximity and preferably comfortably touching the top surface of the finger, pressing the studs into the corresponding holes to lock the two bands, and thereby forming an overlapping ring-like structure. 
     The length of the band in the single-band embodiment is not critical, but it should be sufficiently long so that its engagement means, e.g., holes, can engage the corresponding engagement element, e.g., studs, located in the embodiment shown in FIG. 9 as elements  16 . A single band can usefully extend from the place where it connects to element  12  outwardly, from about 1.5 to about 3.25 inches; preferably from about 1.75 to about 3 inches; more preferably from about 2 to about 2.75 inches, for example such a band can be about 2.5 inches long. If the side band is sufficiently long it may extend beyond the side of  12  when the band is engaged on the finger, but such am extension should not interfere with use of the stylus, particularly if, after sizing the stylus to the user s finger and engaging, e.g., the studs and holes, the unneeded length of the side bard is marked, cut and discarded. Similarly, if hook and loop material is used, hook material can be placed in the recessed area of  12  and loop material on the appropriate surface of the side band. After fitting the band to the finger, excess band length is marked so that it can be cut and discarded. In this manner the out end of the side band can be flush with the side of element  12  (FIGS. 6 and 7 at  22 ), as illustrated in FIGS. 6 and 7 at  23 . 
     When a single band is used, as illustrated in FIGS. 6 through 10, studs  16  can be located at the lower surface of element  12 , preferably in a recessed area approximately the thickness of the side band so that the studs, also preferably approximately of a height equal to the thickness of the side band, do not extend beyond the lower surface of  12 . To engage the stylus to the finger, the single band is rotated over the top surface of the finger so that it is in contact therewith and the holes in the band are aligned with the studs and pressed together to fix the ring-like structure to the finger with the side band preferably in thickness alignment with the lower surface of  12  as indicated at  23 . In this arrangement, it can be more convenient to align the holes with the studs since the studs are not deflected from the vertical by bending, as may occur in the case of the two-band engagement means. As described above, various other engagement means similarly can suitably be employed. The methods or structures described above as useful for linking or attaching a single side band to the stylus, in addition to the use of studs and holes, are illustrated in FIGS. 12A-F as follows: A illustrates hooks at  16  and loops at  15 ; B illustrates adhesive layers at  15  and  16 , and, as described above, such layers can, in one instance comprise a semi-permanent adhesive and in another instance, a permanent adhesive; C illustrates buttons at  16  and holes at  15 ; D illustrates one component of snap elements at  16  and the other component at  15 ; E illustrates magnetic strip layers at  16  and  15 ; and F illustrates angled teeth and ridges at  16  and  15 . 
     On one band are male studs located at  16  in FIGS. 4 and 5. These studs (e.g. mushroom-shaped, although it is acceptable to use any shape known in the art that results in secure engagement), snap into the female receptors, located at  15 . The multiple number of female receptors located at  15  in combination with the multiple number of studs allow for a large range of adjustability previously unavailable in a finger stylus. Similarly, the use of hook and loop material (or any of the alternative engagement means described hereinabove) in the dual band or single band arrangement also facilitates convenient adjustment of the stylus. In this manner, the majority of the human population&#39;s index finger circumference can be accommodated. When sized and snapped together, indicated at  17 , the adjustable finger stylus of FIG. 1 engages the user&#39;s index finger. Preferably, the fingernail and cuticle are not covered, providing maximum comfort during long periods of use. 
     It is particularly preferred that the adjustable stylus of the present invention be molded as a unitary structure. In order to facilitate such molding, plastic or modified plastic compositions can be used, e.g., polyethylene and polypropylene homopolymers and copolymers, elastomeric thermoplastic compositions, etc. Various molding methods well known in the art can be used, including compression and injection molding; injection molding is preferred. Furthermore, the structure can be molded using compositions that include various additives to promote environmental stability against oxidation and ozone as well as fillers and coloring agents to alter the strength, flexibility and appearance of the stylus for improved functionality and customer acceptance. 
     Although the invention herein has been described with reference to particular embodiments, it is understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.