III USOO5212473A United States Patent (19) 11 Patent Number: 5,212,473 Louis (45) Date of Patent: May 18, 1993 (54) MEMBRANE KEYBOARD AND METHOD 4,933,522 6/1990 Celander ............................. 200/513 OF USNG SAME 5,119,078 6/1992 Grant .................................. 340/71 75 Inventor: William M. Louis, Encinitas, Calif. OTHER PUBLICATIONS 73 Assignee: Typeright Keyboard Corp., IBM Technical Disclosure Bulletin, "Key Matrix Using Encinitas, Calif. a Fluid Medium' by Cook et al. vol. 13, No. 3, dated Aug. 1970, p. 744. (21) Appl. No.: 658,541 IBM Technical Disclosure Bulletin, "Briefcase-Porta 22 Filed: Feb. 21, 1991 ble Text-written with 100-key Full-Size Keyboard' by 51) Int. Cl............................................... Goog 3/oz Pechanek et al. vol. 27, No. 4A, dated Sep. 1984, pp. 52 U.S. C. ...................................... 340/711; 341/22, 2002-200 ... if 58 Field341/27, of Search 200/513, ....................... 200/516, 340/711,700, 200/517,361/380 407, puter"IBM.Techniel by IBM Corp.,Pisclosure vol. 32,Bullein, No. 10B,Solding dated Mar.in 341/21, 22, 27, 24; 200/512.5 A, 513,511,517, 1990, pp. 266-267. 520,521,923,920,400/100,412,4913,680,682,.691, 516, 515; 248/917,921,918,922,919, PrimaryE.E.E." Examine-Jeffery A. Bri 693; 364/709.06, 710.01, 189, 708; 361/380; Attorney, Agent, or Firm-Bernard L. Kleinke; Jerry R. 235/1 D Potts; William Patrict Waters (56) References Cited 57 ABSTRACT U.S. PATENT DOCUMENTS A membrane keyboard producing audible and tactile 2,527,016 10/1950 Loung ................................. 400/680 responses when individual character keys are de 3,860,771 /1975 Lynn et al..... 400/93 pressed. To facilitate typing efficiency, the keyboard 4.ii3212Si. 5/i9782. cofiden.yer a as a a . .2%26, heightshas membrane and adjustable characters sensory keys withresponses. different transverse 4,334,280 6/1982 McDonald 364/709.06 4,640,994 2/1987 Komaki .............................. 200/5 A W 27 Claims, 6 Drawing Sheets KEY 35 KEY36 3A J Ed EXTENSION - a para- a - TO other 72 CARACER 74A PULSE KEYS GENERATOR - \, 74 POTO. ELECTRIC ACTUATOR SENSENGFORCE RESISTER KEYPAD 3C HEG CRCU 71 FreQUENCY KEYPA y CUT-OFF CRC to other CHARACER S KEYS - - - - - 6S - - - - -5ETENSNKaeXTENSION y 8 O KEXTENSION Milt FEEosE. ACK MCROPROCESSORAND91 CONTROL MANNPUBUS 7 I 92 NSOEKEYBOARD CONTRONEWE 4 outsidecrisinskrvaord EYBOARD It 94 - - - - - - - - LOU POWER SPEAKER AMPLER U.S. Patent May 18, 1993 Sheet 1 of 6 5,212,473 EH - a ams SSs U.S. Patent May 18, 1993 Sheet 2 of 6 5,212,473 KEY 35 KEY 36 3A J. J. > EXTENSION thod up w is a 72 TO OHER CHARACTER 74A PULSE KEYS GENERATOR 74 PHOTO ELECTRIC ACTUATOR FORCE SENSING RESISTER KEYPAD 3C CIRCU HIGH 7 FREGUENCY KEYPAD y CUT-OFF CIRCUT TO OTHER CHARACTER CIRCUIT lar - - - EXEXTENSION 69 TT CE EXTENSION 81 . {E EXTENSION TACTLE 91 ICFEEDBACK MICROPROCESSOR AND CONTROL HUMAN INPUT BUS - 87 Y. sensitivity 92 INSIDE KEYBOARD I LEVEL ar-l- --l c control - oUTSIDE KEYBOARD CPU - - - - - - - LOUD POWER SPEAKER AMPFER No 97 89 U.S. Patent May 18, 1993 Sheet 4 of 6 5,212,473 U.S. Patent May 18, 1993 Sheet 5 of 6 5,212,473 36 Fa as Nigi/ra ZZZZZZZZ,NNN U.S. Patent May 18, 1993 Sheet 6 of 6 5,212,473 f22A KEY 137 KEY 38 KEY 139 J. J. J. R> EXTENSION - - - - -168 TO OTHER CHARACTER PULSE KEYS GENERATOR CONDUCTIVE COL SENSING RESISTOR 122C KEYPAD CONTROL KEYPAD UNIT CONTROL UNIT TO OTHER CHARACTER SWITCH KEYS CIRCUIT ->EXTENSION 123 KoEXTENSION y 182 {E EXTENSION TACTILE 183 Ji.CONTROL MCROPROCESSORHUMAN INPUT BUS AND 187 85 Y SENSTvry I LEVEL J 184 - - - - - - - - CONTROL 14 CPU - t L - - - - - Fig. 8 OUD POWER SPEAKER AMPLIFIER Nao 189 190 N-186 5,212,473 1. 2 keyboard and method of using it should help relieve MEMBRANE KEYBOARD AND METHOD OF stress and thus help prevent physical injuries to the user. USING SAME This should be accomplished without cumbersome, mechanical adjustments of the keyboard housing. More CROSS-REFERENCE TO RELATED 5 over, at the same time, it should be constructed to facili APPLICATION tate fast and accurate keyboard entry, so that a new user Copending U.S. patent application, entitled "KEY can quickly learn to use such a new membrane key BOARD ARRANGEMENT AND METHOD OF board, with little or no unwanted time consuming de USING SAME,' filed concurrently herewith on Feb. lays. In this regard, some one who is trained in touch 21, 1991, assigned Ser. No. 07/659,604, is hereby incor typing techniques, should be able to use such a new porated by reference as if fully set forth herein. membrane keyboard with little or no training. Therefore it would be highly desirable to have a new TECHNICAL FIELD and improved membrane keyboard, which would be The present invention relates in general to keyboards comfortable to use in a fast and convenient manner, and and methods of using them. The invention more partic which could be used in a less physiologically stressful ularly relates to a membrane keyboard for helping to e facilitate the entry of information in a fast and accurate manner, while helping to relieve physical stress on the DISCLOSURE INVENTION Se. Therefore, it is the principal object of the present 2O invention to provide a new and improved membrane BACKGROUND ART keyboard and method of using it, to help the user know There have been many different types and kinds of when the information has been successfully entered. keyboards for producing signal responses when de Another object of the present invention is to provide pressed. For example, membrane keyboards are usually such a new and improved membrane keyboard and generally flat or planar in configuration. They do not 25 method of using it, to enable a user to enter information ordinarily have the same type of audible and tactile in a fast and accurate manner, without undue physiolog feedback response as the conventional discrete keys. ical stress to the user. The keys of membrane keyboards are usually generally Briefly, the above and further objects of the present flat and have little or no perceivable travel, and thus little or no tactile response is produced when depressed 30 invention are realized by providing a membrane key Also, there is usually no perceivable audible sound, board construction with a group of membrane keys, such as a "click' heard by a discrete key. which are adjustable as a group for tactile and audible The lack of such sensory responses causes a user to be responses. The keys are arranged in staggered rows and uncertain that individual keys have been depressed suf columns to facilitate speed and accuracy of the opera ficiently to produce a character. Thus, the user can 35 tor. The keys have different heights for helping a user to become frustrated and is oftentimes unable to enter reach conveniently all of the keyboard keys. The key information in a fast and efficient manner. Therefore, it board includes a pair of inner and outer molded sheets would be highly desirable to have a new and improved to form the keys. A force sensing resistor device is membrane keyboard having audible and tactile feed actuated by the inner sheet when a key is pressed, to back responses to alert the user when the key was prop- 40 cause character information to be entered. A sensory erly actuated to enter the desired information. control circuit including a force producing device, ena Another reason for the poor acceptance of the mem bles tactile and audible responses to be adjusted for the brane keyboard in many applications, is not only the Se. lack of perceivable audible and tactile feedback, but also In another form of the invention, the tactile and audi because the membrane keys are substantially flat. In this 45 ble responses are caused by providing a liquid sealed regard, it has been generally recognized that for rapid between the inner and outer sheets, and electrically and efficient keyboard entry purposes, different keys energized heating coils cause the liquid to expand rap should have different vertical heights and be positioned idly and abruptly to provide a tactile and audible re at different angles, so the user can conveniently reach sponse. all of the keys on the keyboard Such non-uniform posi- 50 tioning of keys is required in part because of the physi BRIEF DESCRIPTION OF THE DRAWINGS cal structure of the hands and fingers of the user, as well The above mentioned and other objects and features as the different finger-to-key strokes utilized for rapid of this invention and the manner of attaining them will keyboard entry. Thus, for efficient use of a keyboard, become apparent, and the invention itself will be best the individual character keys should be arranged in 55 understood by reference to the following description of rows having discrete height differences to provide the the embodiments of the invention in conjunction with keyboard with an overall generally dished working the accompanying drawings wherein: surface. Since membrane keys are substantially flat, FIG. 1 is a pictorial view of a membrane keyboard they do not lend themselves to forming such a dished constructed in accordance with the present invention surface, which is important for helping provide a more 60 and illustrated forming a part of a foldable computer efficient keyboard operation. having a liquid crystal display panel; Additionally, as more fully described in the foregoing FIG. 2 is an enlarged face view of a group of repre mentioned co-pending application, prior known con sentative keys of the keyboard of FIG.