Talking doll having head movement responsive to external sound

Information

  • Patent Grant
  • 6565407
  • Patent Number
    6,565,407
  • Date Filed
    Wednesday, February 2, 2000
    24 years ago
  • Date Issued
    Tuesday, May 20, 2003
    21 years ago
Abstract
A doll includes a plush doll body having a movable head. A body housing within the doll body supports a control and sound circuit which is operatively coupled to a bidirectional motor drive system operative to move the head from side-to-side. A mouth moving mechanism is independently provided within the doll head. The body housing supports a pair of outwardly facing microphones on the right and left side of the housing to detect sound from either side. The control and sound circuit compares the sound energy received by the right side and left side microphones and determines the appropriate direction to pivot or rotate the head to simulate a “listening” attention by the doll.
Description




FIELD OF THE INVENTION




This invention relates generally to talking dolls and particularly to those having additional features to enhance realism in interactive play patterns with children.




BACKGROUND OF THE INVENTION




With the development of relatively low cost commercially available digital sound circuits, practitioners in the toy arts have endeavored to provide various toys with sound or speech capability. One of the most pervasive uses of digital sound producing circuits is found in dolls which exhibit a capability for speaking. Such speaking dolls often include additional features which further enhance the realism of the speaking activity. Thus, dolls have been provided which include movement mechanisms in addition to the speech apparatus to provide realistic features such as mouth movement or the like. While the fabrication of electronic sound producing circuits of the type used in dolls or other toys is subject to substantial variation, all generally include a sound processor or controller together with a memory suitable for storing the digital signals corresponding to various predetermined words phrases or sounds. Such circuits typically utilize a power amplifier to provide sufficient audio power to the audio signals developed by the processor to enable the circuit to drive an acoustic transducer such as a speaker or the like. Throughout the development of speaking and sound producing toys, the direction of development and the challenge to the practitioner of the toy arts has been to provide evermore interesting and amusing talking and sound producing toys.




Not surprisingly, the continued popularity of sound producing toys has prompted practitioners in the toy arts to endeavor to provide ever increasing sophistication and capability in such toys. For example, U.S. Pat. No. 4,245,430 issued to Hoyt sets forth a VOICE RESPONSIVE TOY which seeks an emitted sound such as a child's voice. The toy include control circuitry for activating an associated drive mechanism to turn and/or guide the toy toward the child's voice. A battery-powered motor drive system responds to the control circuitry to move the toy physically in the direction of the detected sound.




U.S. Pat. No. 4,696,653 issued to McKeefery sets forth a SPEAKING TOY DOLL which responds with spoken words and/or sentences to the touching of selected portions of the doll by a user. The toy further includes voice actuation in response to the user's speech which is sensed by a microphone within the toy. In response to the user's speech, the toy randomly selects a sentence which is audibilized by the speech circuitry within the doll.




U.S. Pat. No. 5,324,225 issued to Satoh, et al. sets forth an INTERACTIVE TOY FIGURE WITH SOUND-ACTIVATED AND PRESSURE-ACTIVATED SWITCHES having a toy body resembling a kitten including an extending tail. An operative mechanism within the toy body utilizes a battery-powered motor drive to articulate the toy kitten's tail.




U.S. Pat. No. 4,923,428 issued to Curran sets forth a INTERACTIVE TALKING TOY which speaks and moves certain body parts such as eyes, mouth, head and arms under the control of a microprocessor. Program material selected from a tape storage device incorporated within the body of the toy is used by the processor to respond to human speech.




U.S. Pat. No. 4,221,927 issued to Dankman, et al. sets forth a VOICE-RESPONSIVE TALKING TOY which in response to a complex sound such as human speech generates a train of audio pulses. The pulses are pseudo-random with respect to frequency composition and duration. The resulting sounds simulate syllabic speech.




U.S. Pat. No. 4,913,676 issued to Koguchi, et al. sets forth a MOVING ANIMAL TOY having a motor operatively coupled to the upper and lower pivotally supported beaks of a bird-like body. Additional apparatus also driven by the motor slowly twists the head of the toy sideways. When a voice is uttered against the toy, it is received through a microphone by a voice recording and reproducing device. After a specified time elapses, the voice is reproduced by the toy.




U.S. Pat. No. 4,950,200 issued to Currin sets forth a WHISPERING DOLL having a tape deck processing an endless loop tape upon which multiple tracks of speech are stored. The tape playing device is responsive to a plurality of switches placed about the toy body.




U.S. Pat. No. 5,316,516 issued to Saitoh sets forth an ANIMATED SINGING TOY BIRD WITH EXTERNAL STIMULUS SENSOR capable of carrying out movement simulating a real bird. The body is arranged so as to be movable with respect to the leg section and the head is further movable with respect to the body. The toy bird may be actuated to produce bird-like sounds in response to sound, light or other stimulus.




U.S. Pat. No. 5,356,326 issued to Ting sets forth a SHAKING TOY having a plush figure resembling a monkey supported within a surrounding cage. In response to stimulus, the toy figure swings back and forth in the cage. An accompanying sound is generated within the toy figure.




U.S. Pat. No. 5,376,038 issued to Arad, et al. sets forth a DOLL WITH PROGRAMMABLE SPEECH ACTIVATED BY PRESSURE ON PARTICULAR PARTS OF HEAD AND BODY in which a doll includes an internal speech producing mechanism together with a plurality of pressure responsive switches supported upon different portions of the body. The speech system responds to the stimulus of one or more of the body supported switches to produce sound.




U.S. Pat. No. 5,607,336 issued to Lebensfeld, et al. sets forth a SUBJECT SPECIFIC WORD/PHRASE SELECTABLE MESSAGE DELIVERING DOLL OR ACTION FIGURE which is capable of providing when activated words or phrases specifically relating to a particular subject, activity, profession or other area of interest for which the doll or action figure is dressed. This selectability is provided by utilizing a doll or action figure which incorporates an audio generator contained therein together with message containing components removably connected with the outfits of wearing apparel.




U.S. Pat. No. 5,735,726 issued to Cohen sets forth a ANIMATED SITTING AND STANDING SANTA CHARACTER having a base upon which a chair is supported together with a toy figure resembling Santa Claus. The toy figure is multiply articulated and is coupled to a drive mechanism which allows the toy figure to move between a standing and seated position upon the chair.




While the foregoing described prior art devices have to some extent improved the art and in some instances enjoyed commercial success, there remains nonetheless a continuing need in the art for evermore improved, interesting and amusing toy figures and dolls which utilize speech simulation.




SUMMARY OF THE INVENTION




Accordingly, it is a general object of the present invention to provide an improved talking doll. It is a more particular object of the present invention to provide an improved talking doll having a head movement which provides a more realistic response by the doll.




In accordance with the present invention, there is provided a talking doll comprising: a doll body having a torso and a head; a body housing supported within the torso-and defining an interior body cavity; a head housing within the head pivotally coupled to the body and defining an interior head cavity; a reversible motor supported within the interior body cavity; first gear means operatively driven by the reversible motor; a shaft coupler operatively driven by the first gear means; a shaft having a first end engaging the shaft coupler and a second end; a head coupler coupling the second end to the head housing; a control and sound circuit having a left microphone, a right microphone, sound producing means and means responsive to the microphones to energize the reversible motor in a first direction in response to sound energizing the left microphone and in a second direction in response to sound energizing the right microphone; and a position switch operatively coupled to the shaft coupler providing an off signal to the control and sound circuit when the shaft coupler is pivoted left or right beyond a predetermined position, the head being pivoted to left or right in response to sound from left or right respectively.











BRIEF DESCRIPTION OF THE DRAWINGS




The features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in the several figures of which like reference numerals identify like elements and in which:





FIG. 1

sets forth a partially sectioned front perspective view of a doll constructed in accordance with the present invention;





FIG. 2

sets forth a partially sectioned front view of the housing and operative mechanism of the present invention talking doll;





FIG. 3

sets forth a partial section view of the operative mechanism of the present invention talking doll taken along section lines


3





3


in

FIG. 2

;





FIG. 4

sets forth a partial section side elevation view of the head moving mechanism of the present invention talking doll; and





FIG. 5

sets forth a block diagram of the control system operative within the present invention talking doll.











DESCRIPTION OF THE PREFERRED EMBODIMENT





FIG. 1

sets forth a partially sectioned front perspective view a doll constructed in accordance with the present invention and generally referenced by numeral


10


. Doll


10


includes a body


11


formed of a conventional plush fabrication material and having a head


12


, a pair.of arms


14


and


15


, and a pair of legs


16


and


17


. Arms


14


and


15


support hands


18


and


19


while legs


16


and


17


support feet


20


and


21


. Head


12


further defines a movable mouth


13


. In the preferred fabrication of the present invention, hands


18


and


19


support pressure responsive switches


22


and


23


while feet


20


and


21


support switches


24


and


25


.




In further accordance with the present invention, body


11


supports a relatively rigid body housing


30


which in turn supports a movable head housing


40


within head


12


. Housing


40


is pivotably joined to body housing


30


by means set forth below in greater detail. The frontal portion of body housing


30


further supports a speaker grille


26


having a plurality of sound emitting apertures formed therein.




In accordance with an important aspect of the present invention, body housing


30


supports a right side microphone


31


and a left side microphone


32


(microphone


32


seen in FIG.


2


).




By means set forth below in greater detail, head housing


40


is moved with respect to body housing


30


in response to sound detected by microphones


31


and


32


(microphone


32


seen in FIG.


2


). In further accordance with the operative mechanism set forth below in greater detail, sound detected at right microphone


31


triggers a movement of head housing


40


and head


12


in the direction indicated by arrow


34


. Conversely, the operative mechanism within body housing


30


set forth below responds to sound detected by left side microphone


32


(seen in

FIG. 2

) by pivoting head housing


40


and head


12


in the direction indicated by arrow


33


. Concurrently, a sound producing circuit set forth below in greater detail within body housing


30


causes predetermined sounds to be emitted from speaker grille


26


. In accordance with the operative mechanism set forth below in FIG.


4


in greater detail, mouth


13


is moved up and down in the directions indicated by arrows


35


each time sound is outputted through speaker grille


26


to give doll


10


the appearance of speaking.




In operation, the user is able to activate the sound circuit within doll


10


by actuating switches


22


,


23


,


24


or


25


to stimulate sound production by the sound circuit within doll


10


. In addition, doll


10


responds to sound detected from sources on either side of the doll by turning head


12


toward the source of sound. This direction determination utilized in turning head


12


in the proper direction is provided by the system set forth below in greater detail. However, suffice to note here that sound reaching doll


10


from its right side is maximally detected by right side microphone


31


while sound reaching doll


10


from its left side is maximally detected by left side microphone


32


(seen in FIG.


2


). In response to detected sound which is maximum from either microphone, doll


10


is actuated to pivot head


12


in the corresponding direction. This action allows doll


10


to exhibit an apparent reaction to a child user speaking or other sounds by turning in the appropriate direction toward the source. This action greatly enhances the realism and interactive appearance of doll


10


.





FIG. 2

sets forth a partially sectioned front view of body housing


30


and head housing


40


showing the operative mechanism of the present invention doll therein. As described above, body housing


30


supports a right side microphone


31


and a left side microphone


32


. As is also described above, body housing


30


is coupled to a pivotally supported head housing


40


. Head housing


40


and body housing


30


are joined by a head coupler


66


which is set forth below in

FIG. 4

in greater detail. A plurality of batteries


36


are supported within the bottom end of body housing


30


. Additionally, a control and sound circuit


80


is also supported within body housing


30


. Body housing


30


defines an interior cavity


50


within which a motor housing


51


is supported. Motor housing


51


supports a motor


52


having an output pulley


53


driven thereby. Pulley


53


is coupled to a combination pulley and gear


55


by a belt


54


. The gear portion of combination pulley and gear


55


engages a gear


56


which in turn drives a worm gear


57


.




A coupler


59


supports a gear


58


engaging worm gear


57


. Coupler


59


further supports a rotary switch


61


and a bearing


62


. Switch


61


and bearing


62


are supported within a slot


60


formed within motor housing


51


. The upper end of coupler


59


receives the bottom end of a shaft


63


. Shaft


63


extends upwardly through body housing


30


and is rotatably supported by a bearing


65


. By means set forth below in

FIG. 4

in greater detail, the upper end of shaft


63


passes through bearing


65


and engages head coupler


66


of head housing


40


. Thus, head housing


40


is pivotally movable in response to pivotal movement of shaft


63


in the manner indicated by arrows


69


and


79


. Shaft


63


is hollow allowing a plurality of wires


64


to pass upwardly from sound and control circuit


80


into mouth drive housing


67


.




The apparatus within mouth drive housing


67


is set forth below in

FIG. 4

in greater detail. However, suffice it to note here that mouth drive housing


67


includes a forwardly extending mouth link


69


which in the manner described below is operative to manipulate mouth


13


(seen in

FIG. 1

) to simulate mouth movement during speaking action of doll


10


.




In operation, motor


52


responds to control and sound circuit


80


in the manner described below in

FIG. 5

to rotate either direction. Sound and control circuit


80


responds to sound energy received by right microphone


31


and left microphone


32


to actuate motor


52


in a corresponding direction. Thus, for example, sounds reaching doll


10


from the doll's right side provide maximal energy at right side microphone


31


in response to which sound and control circuit


80


energizes motor


52


to rotate in a corresponding direction. The rotation of motor


52


rotates output pulley


53


which in turn rotates combination pulley and gear


55


through the coupling of belt


54


. As combination pulley and gear


55


rotates in a selected direction, gear


56


drives worm gear


57


in a resulting direction of rotation. Gear


58


is rotated by the rotation of worm gear


57


to produce rotation of coupler


59


and shaft


63


. Because the maximal sound energy was received at right side microphone


31


, sound and control circuit


80


selected the direction of rotation of motor


52


which would result in rotation of coupler


59


and shaft


63


in the direction indicated by arrow


69


. The engagement of shaft


63


with coupler


59


and the further engagement of shaft


63


with head coupler


66


causes head housing


40


to correspondingly pivot or rotate in the direction indicated by arrow


69


. The result of this action is a movement of the head of doll


10


in the manner described above in

FIG. 2

to produce a head turning toward the detected source of sound providing a realistic response to the speaking child or other sound source. In accordance with the operation of switch


61


described below in conjunction with

FIG. 3

, motor


52


remains energized by sound and control circuit


80


and thereby continues to pivot or rotate coupler


59


and shaft


63


until switch


61


reaches a predetermined position at which point switch


61


produces a signal coupled to sound and control circuit


80


which terminates the energizing of motor


52


. This in turn stops head housing


40


at a predetermined angular position to the right side of doll


10


.




Conversely, the detection of maximal sound energy by left side microphone


32


causes control and sound circuit


80


to energize motor


52


in the opposite direction of rotation. This opposite direction rotation is coupled through pulley


53


and belt


54


to combination pulley and gear


55


. This in turn rotates gear


56


and worm gear


57


in the opposite direction to that caused by energizing of right side microphone


31


. Correspondingly, gear


58


and coupler


59


are rotated in the direction indicated by arrow


79


. This rotation or pivotal movement in the direction indicated by arrow


79


causes a corresponding pivotal movement or rotation of head housing


40


to produce the left side turning movement of doll


10


indicated by arrow


33


in FIG.


1


. Once again, in accordance with the operation of switch


61


set forth below in

FIG. 3

in greater detail, once coupler


59


has rotated or pivoted to a predetermined left side direction, the operation of switch


61


produces a signal condition which causes control and sound circuit


80


to cease energizing motor


52


. This in turn terminates the rotation or pivotal movement of head housing


40


and head


12


(seen in

FIG. 1

) to the left side of doll


10


.




In the preferred fabrication of the present invention, control and sound circuit


80


responds to an absence of sound energy at right side microphone


31


and left side microphone


32


extending beyond a predetermined time to energize motor


52


so as to return head housing


40


and head


12


to the forwardly extending rotational position shown in FIG.


1


.





FIG. 3

sets forth a section view of switch


61


taken along section lines


3





3


in FIG.


2


. As described above, switch


61


is supported within a slot


60


formed in motor housing


51


(seen in FIG.


2


). Switch


61


may be constructed in accordance with conventional fabrication techniques utilizing a printed circuit board


70


upon which a plurality of conductive paths


76


are formed. A plurality of connecting wires


74


and


75


operatively couple conductive paths


76


of printed circuit board


70


to motor control and sound circuit


80


(seen in FIG.


2


). In accordance with conventional fabrication techniques, switch


61


includes a rotating member


78


which is engaged by coupler


59


and which supports a plurality of movable contacts


71


,


72


and


73


. The operation of switch


61


is substantially conventional in that it functions by the interaction of conductive paths


76


and contacts


71


,


72


and


73


to provide the appropriate electrical signals to sound and control circuit


80


in response to rotational position of rotating element


78


. The position of rotating element


78


corresponds directly to the position of coupler


59


. As a result, the pivoting or rotating of coupler


59


described below in response to energizing of motor


52


causes a corresponding movement of contacts


71


,


72


and


73


with respect to conductive paths


76


. At each selected position of conductive paths


76


, the desired one of contacts


71


,


72


or


73


is moved upon the desired one of conductive paths


76


to produce an appropriate position signal for control and sound circuit


80


(seen in FIG.


2


).





FIG. 4

sets forth a partially sectioned side view of head housing


40


and mouth drive housing


67


together with the mouth moving mechanism supported therein. Doll


10


includes a body housing


30


supporting a head housing


40


. Head housing


40


includes a mouth drive housing


67


secured thereto by conventional fasteners (not shown). Mouth drive housing


67


is joined to a head coupler


66


.




Body housing


30


supports an upwardly extending shaft


63


having a bearing


65


and an upper end


90


. End


90


of shaft


65


passes through a bearing


91


supported within head coupler


66


. Mouth drive housing


67


includes a plate


92


having a downwardly extending tab


93


which is received within and which engages end


90


of shaft


63


. Thus, the rotational or pivotal movement of shaft


63


described below in conjunction in

FIG. 2

is imparted to mouth drive housing


67


and head housing


40


through the engagement of tab


93


within end


90


of shaft


63


. Bearing


91


facilitates this pivotal or rotational movement.




Mouth drive housing


67


includes an interior cavity


95


supporting a motor


96


. Motor


96


includes an output pulley


97


which is coupled to a pulley


99


by a belt


98


. Pulley


99


is joined to a worm gear


100


which is rotatably supported within interior cavity


95


. A gear


101


is rotatably supported upon a shaft


102


within interior cavity


95


and further supports an eccentric cam


103


. A movable arm


110


includes a link


68


at its outer end and a slot


112


at its inner end. Arm


110


further includes a pin


111


which engages eccentric cam


103


. A slot


112


is formed in arm


110


and receives shaft


102


.




In operation, control and sound circuit


80


(seen in

FIG. 2

) provides operative power to motor


96


energizing motor


96


and rotating output pulley


97


. The rotation of pulley


97


,is coupled to worm gear


100


via belt


98


and pulley


99


. Rotation of worm gear


100


rotates gear


101


which in turn rotates eccentric cam


103


. As cam


103


rotates, pin


111


is moved forwardly and rearwardly in an oscillatory motion indicated by arrows


115


. Link


68


is joined to the fabric forming mouth


13


of head


12


in a conventional attachment (not shown) such that the front to back oscillatory motion of link


68


caused by the motion of arm


110


moves mouth


13


vertically in the directions indicated by arrows


116


. This movement simulates the speaking action of doll


10


. In the preferred fabrication of the present invention, motor


96


is energized by control and sound circuit


80


(seen in

FIG. 2

) each time doll


10


speaks.




In accordance with the preferred fabrication of the present invention, it will be noted that the operative coupling between shaft


63


and head housing


40


together with the provision of an independent mouth moving mechanism energized by motor


96


within mouth drive housing


67


allows mouth


13


to be moved during speech regardless of the pivotal or rotational position of head


12


. Accordingly, doll


10


is able to do the mouth movement concurrent with speech regardless of whether head


12


is pivoted to the left side, right side or any position therebetween.





FIG. 5

sets forth a block diagram of control and sound circuit


80


. Control and sound circuit


80


includes a comparator


81


operatively coupled to right microphone


31


and left microphone


32


. Comparator


80


provides a pair of output signals to a motor control


82


. Motor control


82


receives operative power from battery


36


and is further coupled to a bidirectional motor


52


. Motor


52


is mechanically coupled in the manner set forth above in

FIG. 2

to a position switch


61


. A head


12


is mechanically coupled to motor


52


in the manner described above in

FIGS. 2 and 4

. Switch


61


is further coupled back to motor control


82


. A sound circuit


83


is coupled to comparator


81


and produces sound output signals which are coupled to a conventional speaker


84


. A jaw motor


96


is operatively coupled to sound circuit


83


.




In operation, comparator


81


receives electrical signals in response to external sound from either or both of microphones


31


and


32


. In the event either microphone is energized solely in response to sound from either side of the present invention doll, comparator


81


produces a signals indicative of the microphone side which is energized. This signal is applied to motor control


82


. In the event both microphones


31


and


32


receive sound simultaneously, comparator


81


functions in the manner set forth in the above-described prior art systems to determine the greater sound energy received between microphones


31


and


32


. In response to the determination of the greater sound energy received, comparator


81


produces a corresponding direction control signal to motor control


82


.




Motor control


82


responds to a direction signal from comparator


81


to energize bidirectional


52


in a corresponding direction of rotation. The rotation of motor


52


is mechanically coupled to a position switch


61


and to head


12


. Correspondingly, head


12


and switch


61


are rotatably moved until the position obtained by switch


61


corresponds to a shutoff or termination position. Once motor


52


has rotated switch


61


in a given direction a sufficient distance to cause switch


61


to turn off,- a signal condition is returned to motor control


52


causing the termination of operation of motor


52


. This in turn terminates the pivotal or rotational movement of head


12


.




Comparator


81


may also respond to the input energy received at microphones


31


or


32


to energize sound circuit


83


. Energizing sound circuit


83


causes an output applied to speaker


84


corresponding to a selected stored audio response. Additionally, sound circuit


83


, when energized to produce sound, also activates jaw motor


96


causing the simulation of mouth movement described above in FIG.


4


. Once the operation of sound-circuit


83


terminates, a corresponding termination of mouth movement also occurs.




Thus, what is provided by the present invention doll is a simple and straight forward system by which a plush doll is provided with head motion simulating the doll directing its attention to sound received from either side due to the position of a sound source such as a child user. In the preferred fabrication of the present invention, the inventive doll is responsive to virtually any sound source on either side of the doll to provide the head turning movement in apparent “listening” response to the sound. Thus, the present invention doll is able to participate in a further play pattern in which a second similar doll is positioned in reasonable proximity to the inventive doll. Under this circumstance, a pair of the present invention dolls together with the child user may provide response to each doll as it speaks and to the child user as the child also speaks. A further plurality of dolls may be used such as three or four or more dolls to provide further amusement and play value.




While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects. Therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.



Claims
  • 1. A talking doll comprising:a doll body having a torso and a head; a body housing supported within said torso and defining an interior body cavity; a head housing within said head pivotally coupled to said body and defining an interior head cavity; a reversible motor supported within said interior body cavity; first gear means operatively driven by said reversible motor; a shaft coupler operatively driven by said first gear means; a shaft having a first end engaging said shaft coupler and a second end; a head coupler coupling said second end to said head housing; a control and sound circuit having a left microphone, a right microphone, sound producing means and means responsive to said microphones to energize said reversible motor in a first direction in response to sound energizing said left microphone and in a second direction in response to sound energizing said right microphone; a movable mouth supported by said head and means for moving said mouth including a single direction motor supported within said interior head cavity wherein said sound circuit causes said means for moving said mouth to be active simultaneously with sound production; and a position switch operatively coupled to said shaft coupler providing an off signal to said control and sound circuit when said shaft coupler is pivoted left or right beyond a predetermined position, said head being pivoted to left or right in response to said sound from left or right respectively and said means for moving said mouth operating independent of left or right pivoting head movement.
  • 2. The talking doll set forth in claim 1 wherein said control and sound circuit includes a comparator coupled to said left and right microphones producing a signal for selecting said first or second direction energizing of said reversible motor.
US Referenced Citations (19)
Number Name Date Kind
4221927 Dankman et al. Sep 1980 A
4245430 Hoyt Jan 1981 A
4659919 Price Apr 1987 A
4696653 McKeefery Sep 1987 A
4757491 Koike Jul 1988 A
4802878 Terzian et al. Feb 1989 A
4911676 Fan Mar 1990 A
4913676 Koguchi et al. Apr 1990 A
4923428 Curran May 1990 A
4950200 Curran Aug 1990 A
5316516 Saitoh May 1994 A
5324225 Satoh et al. Jun 1994 A
5356326 Ting Oct 1994 A
5376038 Arad et al. Dec 1994 A
5407376 Avital et al. Apr 1995 A
5607336 Lebensfeld et al. Mar 1997 A
5713779 Chen Feb 1998 A
5735726 Cohen Apr 1998 A
5855502 Truchsess Jan 1999 A