Patents
This is a partial list of patents. Newly-discovered patents are generally added to the manufacturer page rather than to this page. The fate of this page is uncertain.
Some patents of yet-to-be-seen switches that are not matched to a known series are listed visually under unmatched patents.
See also Japanese patent notes.
Contents
- General switch patents
- Scissor switch patents
- Other keyboard-related patents
- Funny terminology
- Other patents
General switch patents
Known switch types that are yet to be documented anywhere are indicated in bold.
Note that there seems to be a strong tendency for Taiwanese companies to file patents abroad to an individual instead of an organisation, meaning that a number of patents from Taiwanese organisations cannot be tied down to a particular company or product. This is especially frustrating with Win-Join Chen’s patent for the de-facto early 1990s Alps clone design, as it cannot be traced back to either Himake or Tai-Hao, and it could be either company’s product.
Also note that the priority dates are not listed below; some designs are older than the filing date suggests when you take into account earlier patents filed in different countries.
Company | Patent | Title | Filed | Published | Notes |
---|---|---|---|---|---|
Trans Lux Corp | US 3290439 A | Selector | 1945-06-16 | 1948-03-30 | Photoelectric encoder mechanism for devices such as teleprinters |
Monroe Calculating Machine Co | US 2641753 A | Photoelectric keyboard | 1951-07-14 | 1953-06-09 | Optoelectric keypad (identical in concept to full-size keyboards using this principle) |
Willcox | US 3290439 A | Data encoding keyboard | 1963-04-29 | 1966-12-06 | A flat keyboard that in some ways was a precursor to Datanetics elastic diaphragm array |
Angelo De Falco | US 3283274 A | Push button reed switch | 1963-10-04 | 1966-11-01 | This patent was found on a GRI reed switch (similar to KB series but taller, possibly a forerunner) attached to a Mostek/Fairchild F8 Evaluation Kit; curiously, there is no discernible connection between Angelo De Falco and GRI |
Xerox Corp | US 3340401 A | Motionless data input key | 1963-12-26 | 1967-09-05 | Keyboard with photoelectric switches with combined plunger-keycaps |
Kokusai Denshin Denwa KK | US 3363737 A | Pulse generating key board | 1967-04-05 | 1968-01-16 | Some type of electromagnetic sensing implementation |
Friden Inc | US 3465099 A | Optical encoder | 1967-09-05 | 1969-09-02 | Optoelectric keyboard; note that Friden were by this time owned by Singer |
Singer Co | US 3767022 A | Return spring key stem boot | 1970-04-24 | 1973-10-23 | Optoelectric keyboard arrangement, with buckling rubber sleeves |
Texas Instruments Inc | US 3668407 A | Optical switching for keyboard encoder | 1970-05-28 | 1972-06-06 | Optoelectric calculator keyboard |
Cherry Electrical Products | US 3644855 A | Keyboard reed switch | 1970-07-10 | 1972-02-22 | A tactile double-pole reed switch that was briefly advertised around 1971 |
Controls Research Corp | US 3773996 A | Pushbutton switch with coil spring contacts | 1971-05-20 | 1973-11-20 | Controls Research Corp BI-PAC |
Cherry Electrical Products | US 3739127 A | Keyboard pulse switch | 1972-02-17 | 1973-06-12 | A variant of M5 or M6 Series that causes the contacts to re-open immediately after closing, generating a pulse of current; not known to be in any catalogues |
Controls Research Corp | GB 1345831 A | Electrical switch | 1972-05-11 | 1974-02-06 | Controls Research Corp BI-PAC |
International Standard Electric Corp (ISEC) | US 3750150 A | Photoelectric keyboard for data input devices or the like | 1972-07-21 | 1973-07-31 | Optoelectric keyboard arrangement |
U Halfon, M Niv | US 3856127 A | Photo-optical keyboard | 1972-11-24 | 1974-12-24 | Optoelectric keyboard arrangement |
Alps Electric Co Ltd | US 3823292 A | Push-button switch with conductive coil spring contact | 1973-03-16 | 1974-07-09 | Alps spring bridge |
Western Digital Systems Inc | US 3818485 A | Keyboard apparatus | 1973-03-30 | 1974-06-18 | Optoelectric keyboard (this is the patent on the Collimation D40.592) |
Illinois Tool Works Inc | US 3824362 A | Alternate action switch mechanism | 1973-05-23 | 1974-07-16 | ITW first-generation alternate action switch, as seen in the HP 02645-60023 ca. 1978 as magnetic valve |
Illinois Tool Works Inc | US 3882295 A | Tactile feedback switch mechanism | 1973-10-04 | 1975-05-06 | Tactile feedback mechanism for ITW first-generation switches |
J. & J. Marquardt | DE 2360168 A1 | Schalter, insbesondere Taster (“Switch, in particular pushbutton”) | 1973-12-03 | 1975-06-05 | Possibly precursors to the Marquardt “Butterfly” switch |
Cherry Electrical Products | US 3849621 A | Illuminated push-button switch | 1974-05-09 | 1974-11-19 | Cherry M41 corner-illuminated (this design was omitted from Serie M7) |
Illinois Tool Works Inc | US 3902032 A | Electrical switch with improved contact structure | 1974-06-07 | 1975-08-26 | ITW first-generation switch, metal contact system (which references Hi-Tek’s patent filed two years earlier) |
Tokai Communication Ind | JP S5276687 A | Push button switch | 1975-12-23 | 1977-06-28 | Tokai MM9 series |
Illinois Tool Works Inc | US 4028696 A | Double depression magnetic keyswitch | 1976-01-26 | 1977-06-07 | Early Ⅲ Cortron (ITW) ferrite core double action switch |
Illinois Tool Works Inc | US 4017850 A | Magnetic keyswitch with two-piece support assembly | 1976-02-02 | 1977-04-12 | Early Ⅲ Cortron (ITW) ferrite core switches |
Alps Electric Co., Ltd. | US 4123641 A | Pushbutton switch | 1977-02-16 | 1978-10-31 | Priority date 1976-02-27 to the Japanese patent; this patent covers the Hirose keycap mount, only it was filed by Alps instead |
Alps Electric Co., Ltd. | US 4153829 A | Pushbutton switch assembly | 1977-02-16 | 1979-05-08 | Never observed in the wild; the patent depicts an older design of switchplate before SKCC series, suggesting that SKCC series was introduced in 1977 or later (and as later patents cite this one, this appears to be only patent for the vertical switchplate design itself) |
Omron Tateisi Electronics Co | JP S53136680 A | Keyboard Switch | 1977-05-04 | 1978-11-29 | Magnetic tactile and click system within a compact reed switch; the switch depicted is not known, but the magnet system has been found in B2H-F7W which is very similar in shape |
Omron Tateisi Electronics Co | JP S57136719 A | Method of Producing Illumination Keyboard Switch | 1979-02-16 1982-01-06 |
1982-08-23 | Covers the internally-sprung centre illumination system found in B2R and B2H, depicted in a Hall effect switch largely identical to B2R; the alternate action mechanism is also covered, although it seems not to match up with the provisions made on B2R, and this arrangement is seemingly also extendable to tactility (based on a fragmentary translation) (The 1979 application date is 「前実用新案出願日援用」 while the application itself is dated 1982, whatever that means …) |
Omron Tateisi Electronics Co | JP S55105916 A | Contactless Keyboard Switch | 1979-02-06 | 1980-08-14 | Covers the Hall effect arrangement in B2H and the Hall equivalent to B2R |
Unisys Corp (originally Burroughs Corp) | US 4278965 A | Photo-optical keyboard having n-key rollover | 1979-09-14 | 1981-07-14 | Opto-electric keyboard |
Omron Tateisi Electronics Co | JP S5743324 A | Electrostatic Capacitance Type Keyboard Switch | 1980-08-26 | 1982-03-11 | Some kind of foam and foil arrangement, with an optional spring-over-foam arrangement to get a more linear feel |
Omron Tateisi Electronics Co | JP S5746418 A | Electrostatic Capacitive Keyboard Switch | 1980-09-02 | 1982-03-16 | A revision of the previous patent to include Topre-like springs, possibly over some kind of rubber mat (a translation would make things clearer) |
Omron Tateisi Electronics Co | JP S5750721 A | Electrostatic Capacitive Keyboard Switch | 1980-09-12 | 1982-03-25 | A revision of JP S5743324 A (some kind of foam and foil including spring over foam); a translation would reveal the specifics |
Omron Tateisi Electronics Co | JP S5755014 A | Electrostatic Capacitance Type Keyboard Switch | 1980-09-19 | 1982-04-01 | A revision of JP S5746418 A (foam and foil, and Topre-like springs) |
Rafi & Co Elektrotechnische Spezialfabrik | DE 3037448 A1 | Pushbutton switch assembly - has leads of diode connected directly to internal contact and external contact pin | 1980-10-03 | 1983-10-27 (B1) | Internal diode arrangement for RAFI RS 76 M; Google Patents lists C2 as the grant, but only A1 from 1982-05-13 has the complete set of drawings |
Oak Industries Inc | US 4559426 A | Membrane switch and components having means for preventing creep | 1980-11-03 | 1985-12-17 | Oak Full-Travel Membrane alternate action switch |
アルプス電気株式会社 (Alps Electric Co., Ltd.) | JP S58150232 U | Push-button switch | 1982-03-31 | 1983-10-08 | This is a “switchplate”-based double-action switch, possibly related to the type used in some Canon typewriters. |
Thomas H Gifft | US 4529967 A | Non contacting inductive keyboard | 1982-07-15 | 1985-07-16 | This is an inductive arrangement with the “windings” as PCB tracks, similar to IMS and ADI keyboards |
General Instrument Corporation | US 4453198 A | Linear feel keyswitch with hysteresis | 1982-09-15 | 1984-06-05 | General Instrument S700 Series |
General Instrument Corp | US 4454562 A | Keyswitch with telescoping plunger | 1982-09-15 | 1984-06-12 | General Instrument S700 Series |
Digital Equipment Corp | US 4467150 A | Electronic keyboard | 1982-02-24 | 1984-08-21 | DEC membrane system, as used with the LK201 |
Ing.C.Olivetti E C. SPA | IT 1155954 B | Tastiera a contatti (Contact keyboard) | 1982-09-28 | 1987-01-28 | Olivetti semi-discrete conductive dome |
Oak Industries Inc | US 4479040 A | Tactile feel switch with positive switch actuation | 1983-03-07 | 1984-10-23 | Implementation of tactile feel for what appears to be a derivative of Oak Full-Travel Membrane |
SMK KK | JP S6017 A | Switch Element and Method of Producing the Same | 1983-06-15 | 1985-01-05 | Mitsumi/Hosiden–style contact assembly fitted to a J-M0404–style switch; never seen in the wild |
Rudolf Schadow GmbH | DE 3324253 A1 | Tastenschalter | 1983-07-06 | 1985-01-17 | Never seen in the wild; not confirmed to be keyboard-suitable (more details on the switch contacts in adjacent patent 3324254 A1) |
Mitsumi Electric Co | JP S6063832 A | Pushbutton switch | 1983-09-17 | 1985-04-12 | Some sort of parabolic rate spring arrangement, including a horizontal spring version of Mitsumi miniature mechanical, but without the spring-over-nub arrangement seen in KLT-11 (note that this patent pre-dates the patent on miniature mechanical, below) |
Mitsumi Electric Co | JP S60230317 A | Pushbutton switch | 1984-04-27 | 1985-11-15 | Mitsumi miniature mechanical, linear version (KLM) |
SMK KK | JP S60243912 A | Method of Producing Switch Element | 1984-05-17 | 1985-12-03 | Mitsumi/Hosiden–style contact assembly fitted to a proto–second generation switch; never seen in the wild |
Siemens AG | EP 0164446 B1 | Device for fixing a diode in a push-button housing | 1984-12-14 | 1988-04-27 | Diode fitment to STB 21; for some reason they felt that the diode had to have its legs removed and separate legs used! |
Fujitsu Ltd | US 4803316 A | Push button switch using dome spring and switch element thereof | 1986-10-16 | 1989-02-07 | Fujitsu FES-370 |
Fujitsu Ltd | JP H0615373 Y2 | Pushbutton switch | 1987-08-11 | 1994-04-20 | Fujitsu FES-370 (a different variant to the 1986 US patent) |
立石電機株式会社 (Tateishi Electric Co., Ltd.) | H 01109148 U | Switch | 1988-01-15 | 1989-07-24 | Contact assembly from Omron “Alps-style” switches |
Alps Electric Co Ltd | US 4920245 A | A push-button switch with uniform on and off timings | 1988-06-30 | 1990-04-24 | This patent covers a portion of the Mk II Alps switchplate, specifically a way to improve the injection moulding to get a more consistent pretravel distance (the change from large to small foil, or large to small dimensions, are not included) |
Omron Tateisi Electronics Co. | US 5015811 A | Snap-action pushbutton switch with click sound | 1989-06-13 | 1991-05-14 | Inverted, moving click leaf design for Omron B3G-S switches; never observed in the wild |
Alps Electric Co Ltd | US 5120923 A | Push button switch | 1990-09-18 | 1992-06-09 | Unnamed membrane type; later discovered in the Toshiba T4600C |
Alps Electric Co Ltd | JP H04220915 A | Push-button switch | 1990-12-21 | 1992-08-11 | Alps ultra low profile |
Win-Join Chen | US 5124514 A | Structure of mechanical key switch | 1991-07-08 | 1992-06-23 | Either Himake AK series or Tai-Hao APC series |
Silitek Corporation | US 5310973 A | Structure of key switch | 1991-10-08 | 1994-05-10 | Alternative patent for Silitek (MX mount) dome with slider |
Alps Electric Co Ltd | US 5201824 A | Push button switch | 1992-01-13 | 1993-04-13 | A “division” of US 5120923 A, above |
Monterey International Corp | US5406277A | Structure of the keypad for keyboard | 1993-04-12 | 1995-04-11 | Monterey 0/180° Alps dome with slider (not the same as the well-known 0/90/180/270° version); no spring, dome, contacts or membranes are shown |
Sen-Cheng Wang | US 5380969 A | Computer key | 1993-04-28 | 1995-01-10 | The drawings bear a strong resemblance to Monterey dome with slider |
Daw Shen Chen | GB 2282703 A | Mechanical key switch | 1993-10-05 | 1995-04-12 | Quite possibly Can Technology buckling spring |
Tokai Communication Ind | JP H07220561 A | Contactless switch | 1994-02-01 | 1995-08-18 | Optoelectronic adaptation of Tokai MM9 series, never observed in the wild; patent filed ten months before that of Tokai SPT-0101 |
Liao Ching-Shui | US 5456541 B1 | Key unit of a keyboard | 1994-03-23 | 1995-10-10 | Unrecognised spring-over-membrane type; curiously it depicts ATW Alps clone (as found in the Oriental Tech OK-100 from ca. 1992) as the prior art |
Silitek Corporation | US 6184481 B1 | Key switches for computer keyboards | 1994-03-30 | 2001-02-06 (!) | Silitek (Alps mount) dome with slider |
Mitsumi Electric Co | JP H07326257 A | Pushbutton switch | 1994-05-31 | 1995-12-12 | This is some kind of redesign of KPQ series with what appears to be a single rubber dome sheet (クリックラパーコート) instead of separate buckling rubber sleeves; existing KPQ series is shown as 「別の従来のキーボードスイッチ」 (“another conventional keyboard switch”) |
Focus Electronic Co Ltd | US 5442152 A | Computer key switch | 1994-09-28 | 1995-08-15 | Focus spring over dome — a clicky dome switch similar to Fujitsu Peerless; the click sound is attributed to “barbs” within the spring tube hitting some part of the tube within the slider in which it fits |
Tokai Communication Ind | JP H08167361 A | Semiconductor photocoupling switch | 1994-12-12 | 1996-06-25 | Tokai SPT-0101 |
Silitek Corp | US 5938009 A | Key switch for a keyboard | 1998-08-24 | 1999-08-17 | Silitek spring over dome — a clicky dome switch similar to Fujitsu Peerless (the sudden extension of the coil spring is said to generate the click sound) |
Jing Mold Enterprise Co Ltd | US 6156986 A | Computer key switch | 1999-12-30 | 2000-12-05 | A fairly typical rubber dome switch; notable only as it is from Jing Mold, whose FCC ID is on the Tulip 9151B (also rubber dome) |
ZF Electronics GmbH | EP 2979289 B1 | Key push rod for a key module of a key for a keyboard, key module of one key for a keyboard and method of key module assembly for a key of a keyboard | 2014-02-28 | 2018-02-14 | Damped Cherry MX |
Scissor switch patents
Just listing the priority dates for these as the new Google Patents site doesn’t want to make filing dates easy to access when exploring patents. Note that non-crossed designs (where the two arms are not attached to each other and do not scissor) are also included, and are marked “non-cross”.
This list also covers stabiliser arrangements with scissor arms, as these appear to be precursors to modern scissor switches.
Company | Patent | Title | Priority | Notes |
---|---|---|---|---|
General Instrument Corporation | US 4433225 A | Keytop levelling mechanism | 1983-02-22 | This is a stabiliser design in the form of scissor arms |
Preh GmbH | US 4580022 A | Keyboard key with means for supporting large key surface | 1983-08-17 | This is a stabiliser design in the form of scissor arms (referred to as “shears”) |
Brother Industries Ltd | US 5278371 A | Keyswitch assembly with support mechanism coupled to support plate beneath printed circuit board | 1992-02-14 | |
Brother Industries Ltd | US 5278374 A | Assembly with an asymmetrical resilient spring | 1992-02-14 | |
Alps Electric Co Ltd | US 5488210 A | Push button switch | 1992-06-11 | |
Brother Industries Ltd | US 5463195 A | Key switch | 1993-01-06 | |
Charles E. Emmons | US 5424516 A | Low profile pushbutton switch | 1993-09-23 | A spring-over-membrane design, with a telescoping scissor slider; the scissor arms are arranged such that the coil spring can run down the middle from under the keycap, to the membranes. |
Mitsumi Electric Co | JP H07296673 A | Keyboard switch | 1994-04-22 | Some kind of four-arm non-cross arrangement; figures 5 through 7 show “conventional” keyboard switches for comparison |
Lite-On Singapore Pte Ltd (originally Minebea Co Ltd) | US 5597067 A | Pushbutton switch | 1994-08-03 | |
Mitsumi Electric Co | JP H08124456 A | Keyboard switch | 1994-10-26 | Some kind of non-cross arrangement; figures 4 and 5 show “conventional” keyboard switches for comparison |
Nagano Fujitsu Component Ltd | US 5874696 A | Key switch, keyboard and portable information processing unit with keyboard | 1996-08-12 | Non-cross |
Fujitsu Ltd | JP H11185564 A | Key switch, keyboard and information processor using these | 1997-12-22 | Non-cross |
Nagano Fujitsu Component Ltd | US 6118092 A | Key switch for keyboard | 1998-09-22 | Non-cross |
Fujitsu Ltd, Nagano Fujitsu Component Ltd | US 6257782 B1 | Key switch with sliding mechanism and keyboard | 1998-06-18 | Suggested to be spring-over-membrane |
SMK Corp | US 6297461 B1 | Key switches for computer keyboards | 1999-12-17 | Both leaf spring and dome actuators are implied |
Behavior Technical Computer Corp | US 6572289 B2 | Pushbutton structure of keyboard | 2001-06-28 | |
Minebea Co Ltd | US 6759614 B2 | Keyboard switch | 2002-02-27 | |
Fujitsu Component Ltd | US 7138587 B2 | Key switch, keyboard and key-switch assembling jig | 2004-07-01 | Non-cross |
Fujitsu Component Ltd | US 8624140 B2 | Key switch and keyboard | 2006-07-10 | Non-cross |
Other keyboard-related patents
The following table covers patents for aspects of keyboards other than keystroke sensing. In particular, it lists patents for mechanical shift lock mechanisms. These do not use alternate action switches. Instead, pressing shift lock causes a special mechanism (external to the switch) to hold the key down, and pressing either shift key (or just left shift, if right shift is not connected) releases shift lock. Mechanical shift lock mimiced the shift lock mechanism on manual typewriters, where the shift mechanism could be locked in place for convenient entry of capitalised text.
Also covered are stabiliser mechanisms that do not use scissor arms; those types with scissor arms are covered above alongside scissor switches.
Company | Patent | Title | Filed | Published | Notes |
---|---|---|---|---|---|
Western Electric Co Inc | US 1907930 A | Process of manufacturing electrical contact members | 1930-11-24 | 1933-05-09 | Costruction of crosspoint switch contacts (first of three simultaneously-filed patents on the subject) |
Western Electric Co Inc | US 1907931 A | Process of manufacturing electrical contact members | 1930-11-24 | 1933-05-09 | Costruction of crosspoint switch contacts |
Western Electric Co Inc | US 1907932 A | Process of manufacturing electrical contact members | 1930-11-24 | 1933-05-09 | Costruction of crosspoint switch contacts |
CLARE PENDAR Co | US 3626120 A | Key-locking assembly | 1970-09-30 | 1971-12-07 | Mechanical shift lock mechanism; here, the keycap itself operates the release mechanism |
Cherry Electrical Products | US 3678255 A | Mechanical key lock-in | 1971-06-18 | 1972-07-18 | Mechanical shift lock mechanism, used by M61-0300/0310/0500/0510 (early 1970s) and later M61-0025/0026/0027/0028 (by the late 70s) |
Cherry Electrical Products | US 3711685 A | Keyboard switch actuator | 1971-12-27 | 1973-01-16 | Cherry paddle-type stabiliser, as seen in B70-05AB; replaced with the wire-type stabiliser |
Burroughs Corp | US 4010838 A | Spacer bar mechanism | 1975-01-17 | 1977-03-08 | Space bar stabiliser |
Illinois Tool Works Inc | US 4071719 A | Keyboard switch assembly having actuator interlocking keyboard shift and shift lock and release mechanism | 1976-07-22 | 1978-01-31 | Mechanical shift lock for ITW first-generation switches |
Cherry Electrical Products Corp | US 4188136 A | Keyboard switch actuator and locking assembly | 1978-01-19 | 1980-02-12 | The Cherry stabiliser arrangement (wire-type), plus a mechanical shift lock mechanism (unclear switch types) |
Illinois Tool Works Inc | US 4295012 A | Secretarial shift mechanism for an electric keyboard | 1980-02-04 | 1981-10-13 | Mechanical shift lock for ITW second-generation switchces (both magnetic valve and metal contact are depicted here) |
Honeywell Inc | US 4421432 A | Key switch cap mounting arrangement | 1981-09-04 | 1983-12-20 | Honeywell keycap mount |
IBM | US 4460534 A | Two-shot injection molding | 1982-09-07 | 1984-07-17 | |
アルプス電気株式会社 (Alps Electric Co., Ltd.) | JP S6234723U | キーボードのキートップ取付構造 (“Key top mounting structure for keyboard”) | 1985-08-19 | 1987-02-28 | Stabiliser assembly found in the Zenith Supersport |
Alps Electric Co Ltd | US 4771146 A | Keyboard key top mounting structure | 1987-11-30 | 1988-09-13 | Stabiliser assembly found in the Zenith Supersport |
Key-Tech Inc (later Poly-Flex Circuits Inc.) |
US 4960614 A | Printed circuit board | 1989-06-14 | 1990-10-02 | Improved silver ink for producing tracks on printed circuit boards |
Funny terminology
- film
- membrane sheet
- pushbutton
- “plunger” according to Omron
- shears
- Another term for scissors
- spacer bar
- An old term for space bar
Other patents
The following patents are not for keyboards, but they are notable in relation to keyboards.
Company | Patent | Title | Filed | Published | Notes |
---|---|---|---|---|---|
Olympia Werke AG | DE 3330624 A1 | Push-button switch | 1983-08-25 | 1985-03-14 | This is notable for being a Western example of the folded-plate contact module, akin to that of Mitsumi KAM and Hosiden switches |