Ulllted States Patent [19]
`Faggin et al.
`
`US005920310A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,920,310
`Jul. 6, 1999
`
`[54] ELECTRONIC DEVICE EMPLOYING A
`TOUCH SENSITIVE TRANSDUCER
`
`[75] Inventors: Federico Faggin, Los Altos Hills; Joel
`AI Seely,
`I)I Allen,
`Los Gatos; all of Calif.
`
`[73] Assignee: Synaptics, Incorporated, San Jose,
`cam‘
`
`[21] Appl- NOJ 08/751,182
`[22] Filed
`NOV 15 1996
`'
`'
`’
`Int. Cl.6 ............................ .. G08C 21/00; G09G 5/00
`[51]
`[52] us. Cl. ........................ .. 345/173; 345/174; 345/901;
`178/1801; 178/1803; 178/1807
`[58] Field of Search ................................... ..345/156,158,
`345/159, 169, 173, 174, 901; 178/1801,
`1803, 1807, 1903, 2001
`
`[56]
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`5,469,194 11/1995 Clark ..................................... .. 345/173
`5,495,077
`2/1996 Miller et a1.
`. 345/173
`
`5,583,539 12/1996 Hiketa . . . . . . . . . . . .
`
`. . . .. 345/173
`
`576287031
`
`- 345/173
`5/1997 Kikinis et al-
`Podwalny .............................. ..
`
`Primary Examiner—Vij ay Shankar
`Attorney, Agent; or Firm—Malcolm B. Wittenberg
`[57]
`ABSTRACT
`
`An electronic device is provided making use of a touch pad
`module to implement user input functions. The electronic
`device includes a case having a region of thinner cross
`section than the remaining case side Wall for receiving the
`touch pad module' The case is further provided With a
`through hole in the area of its thinner cross section for
`receiving Control electronics of the touch pad module
`enabling the region of thinner cross section to physically
`support the touch pad module so that the module can be
`thinner than What is conventionally believed to be necessary
`to maintain its physical integrity While in use as an input
`
`d '
`
`.
`
`evlce
`
`5,305,017
`
`4/1994 Gerpheide ............................. .. 345/174
`
`15 Claims, 7 Drawing Sheets
`
`79
`
`8O
`
`78
`
`§’////////> , 1 I I I , 1.
`
`a I I a, //77’///////?
`
`/ /
`
`828
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`TCL EXHIBIT 1069
`Page 1 of 14
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`

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`U.S. Patent
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`Jul. 6, 1999
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`Sheet 1 of7
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`5,920,310
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`FIG. 1
`PRIOR ART
`
`FIG. 2
`PRIOR ART
`
`FIG. 3
`PRIOR ART
`
`30
`29
`28
`WW] Q ,/ .
`32/
`T 34
`
`i8
`. 41/ ///////////I
`T
`32
`
`FIG. 4
`PRIOR ART
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`TCL EXHIBIT 1069
`Page 2 of 14
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`

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`U.S. Patent
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`Jul. 6, 1999
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`Sheet 2 of7
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`5,920,310
`
`FIG. 5
`PRIOR ART
`
`FIG. 6
`PRIOR ART
`
`f ////////////A
`/
`V/l////////////A/
`74 LJ V/////>/////<// A
`54
`48
`
`FIG. 7
`PRIQR ART
`
`TCL EXHIBIT 1069
`Page 3 of 14
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`

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`U.S. Patent
`
`Jul. 6, 1999
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`Sheet 3 of7
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`5,920,310
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`FIG. 8
`PRIOR ART
`
`68
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`\
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`j;
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`70
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`FIG. 9A
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`/72
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`74%
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`76
`
`FIG. 9B
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`TCL EXHIBIT 1069
`Page 4 of 14
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`U.S. Patent
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`Jul. 6, 1999
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`Sheet 4 0f 7
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`5,920,310
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`79
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`80
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`78
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`Y///////‘/--,/ , , , , , , ,.
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`?. , , 5 , ,m’////////?
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`84 a:
`
`FIG. 10
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`FIG. 11
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`FIG. 12
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`TCL EXHIBIT 1069
`Page 5 of 14
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`U.S. Patent
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`Jul. 6, 1999
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`Sheet 5 0f 7
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`5,920,310
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`104
`
`l
`\\\
`106
`‘\ “2 108
`\\v J /
`\
`110
`
`FIG. 13
`
`FIG. 14
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`FIG. 15
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`TCL EXHIBIT 1069
`Page 6 of 14
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`U.S. Patent
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`Jul. 6, 1999
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`Sheet 6 of7
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`5,920,310
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`156
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`158160
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`FIG. 17
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`164
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`166
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`168
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`164
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`TCL EXHIBIT 1069
`Page 7 of 14
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`

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`U.S. Patent
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`Jul. 6, 1999
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`Sheet 7 0f 7
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`5,920,310
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`FIG. 19
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`TCL EXHIBIT 1069
`Page 8 of 14
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`

`
`1
`ELECTRONIC DEVICE EMPLOYING A
`TOUCH SENSITIVE TRANSDUCER
`
`TECHNICAL FIELD OF THE INVENTION
`
`The present invention involves an electronic device, such
`as a notebook computer Which makes use of a touch pad
`module to implement user input functions. The physical
`interface betWeen the touch pad module and case housing
`the electronic device have been recon?gured enabling
`extremely thin modules to be employed Which heretofore
`have been deemed to be impractical.
`
`BACKGROUND OF THE INVENTION
`
`As noted above, the present invention involves an elec
`tronic apparatus Which makes use of a touch pad device to
`implement all or a part of its user input functions. Notebook
`and desktop computers as Well as copiers are typical
`examples of such electronic apparatus having need for a
`touch pad device such as that disclosed herein. When used
`in conjunction With a computer, a touch pad alloWs the user
`to manipulate a graphics cursor on a CRT display. The touch
`pad comprises a sensitive planar surface and a means for
`detecting the position of an object, such as a ?nger or a
`stylist, near, or in contact With, the sensitive planar surface.
`The touch pad continuously communicates this position
`information to the electronic apparatus typically at a rate of
`from 40 to 100 HZ.
`The touch pads disclosed herein can be characteriZed as
`having a physical transducer by Which the touch pad detects
`the location of the above-noted ?nger or stylus. For capaci
`tive touch pads, the sensor surface typically consists of tWo
`perpendicular roWs of electrodes separated by a thin dielec
`tric layer. For resistive touch pads, the sensor surface may
`consist of tWo resistive layers separated by spacers. For most
`knoWn types of touch pad devices, the sensor surface itself
`can be constructed from very thin materials and may be no
`more than a feW tenths of a millimeter in total thickness.
`Capacitive touch pads based on Synaptics’ sensor
`technology, for example, have been constructed With a
`sensor surface of only 0.25 mm in thickness. Typically, the
`sensor surface is covered by a thin protective layer Which is
`both durable and pleasant to the touch. Many touch pads use
`textured Mylar (polyester) appliques betWeen 0.1 mm and
`0.3 mm in thickness as a protective layer.
`Control electronics are used in conjunction With the
`sensor surface Which consist of a set of electronic compo
`nents used to process electrical signals produced by the
`sensor surface and communicate those electrical signals to
`the host electronic apparatus. For many types of touch pads,
`the control electronics consist of an integrated circuit to
`directly record and process sensor signals, a micro controller
`chip Which handles control functions and interface With the
`host electronic apparatus and a handful of discreet compo
`nents such as resistors, capacitors, ceramic resonators and
`crystals used in support of either the sensor integrated circuit
`or the micro controller. For some touch pad modules, the
`sensor integrated circuit and micro controller functions are
`subsumed Within a single chip. All knoWn resistive and
`capacitive touch pad technologies require some amount of
`control electronics in order to function.
`In addition to the above, the typical touch pad module
`requires some means of connecting output from the control
`electronics to the host electronic device or apparatus. What
`is typically used is a ?at ?exible cable Which consists of a
`thin ?exible substrate made of, for example, Kapton, With
`several evenly spaced conductive (usually metal) strips
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`deposited on its surface. Typically, the conductive strips are
`covered With an insulator except Within a feW millimeters of
`either end of the cable. The conductors are exposed at their
`ends to facilitate electrical connection When inserted into a
`mating connector. Typically, ?at ?exible cable used With
`touch pad modules use 4.10 conductors (pins) to carry the
`poWer supply and interface signals to the touch pad. Devices
`Which use a ?at ?exible cable, including touch pads, typi
`cally include a mating connector mounted on their PC
`boards or, alternatively, the exposed metal conductors at the
`ends of the ?at ?exible cable may be soldered directly to
`matching pins on a PC board.
`It is the usual practice to provide the touch pad module as
`a self-contained unit Which includes the sensor surface,
`control electronics and some means for connecting the
`module to the host electronic device. The touch pad module
`communicates With the host system via one of several
`pre-de?ned communication protocol standards, for example,
`PS/2 or RS-232 protocols for touch pad modules used in
`notebook computers. Vendors of touch pad modules usually
`sell assembled units to customers Which are traditionally
`manufacturers of notebook computers or some other type of
`electronic host system. Customers generally require that the
`touch pad module be reasonable easy to install into and
`remove from the host system. The touch pad module is
`typically delivered as a printed circuit board With the sensor
`surface disposed on one side and the control electronics
`mounted on the other. For capacitive touch pads, such as the
`Synaptics touch pad, a typical PC board might be 50 mm by
`65 mm in rectangular dimension and 2 mm in thickness.
`In vending a touch pad module to an end user, the module
`manufacturer generally de?nes a “keep-out Zone” Which is
`a three-dimensional spatial region in the shape of the mini
`mum rectangular prism Which encloses all of the control
`electronics as Well as the ?at ?exible cable connector, if any.
`As an example, for the Synaptics standard touch pad module
`model TM 1202SPU, the keep-out Zone is a box approxi
`mately 35 mm by 40 mm by 3 mm roughly centered on the
`reverse (non-sensor) side of the PC board.
`A touch pad module can be made ?exible by producing it
`in the form of a thin, ?exible printed circuit material instead
`of a conventional printed circuit board. Commonly used
`?exible circuit technologies include Mylar substrates, screen
`printed With conductive inks as Well as Kapton substrates
`With deposited metal traces. Both of these technologies are
`suitable for forming multi-layer circuit patterns and both
`provide methods for mounting the control electronics com
`ponents onto substrates. In either case, the thickness of the
`?exible substrate is typically less than 0.3 mm.
`Flexible touch pad modules offer advantages over stan
`dard PC board touch pad modules in some applications. For
`example, the sensor surface of a capacitive touch pad can be
`formed on a region of the ?exible substrate remote from the
`control electronics, alloWing the sensor to be placed ?at on
`the exterior case of the host electronic device Without
`providing any component clearance directly underneath the
`sensor. Flexible touch pad modules may be capacitive in
`Which case the sensor surface is implemented as an array of
`electrodes formed by conductive traces on the ?exible
`surface. Resistive touch pads may also be implemented in
`this regard With the sensor surface formed by application of
`a pressure-sensitive resistive transduce to the ?exible sur
`face substrate.
`Virtually all host electronic devices employing touch pads
`are provided With a case, generally con?gured of plastic
`Which houses the various electronic components making up
`
`TCL EXHIBIT 1069
`Page 9 of 14
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`

`
`3
`the host system. In the case of a notebook computer, a palm
`rest is provided in Which the typical touch pad is mounted.
`The palm rest generally consists of a plastic panel beneath
`the notebook computer keyboard on Which the user rests the
`palms of his hands While typing. Typical palm rests are made
`of textured plastic betWeen 1.5 mm and 2 mm in thickness
`and, as noted above, the palm rest is generally an integral
`part of the structure of the system’s case.
`When the touch pad module is applied to the plastic case
`of the host electronic device, it is generally installed With a
`suitable beZel. The beZel is provided as a rim Which sur
`rounds the sensor surface of the touch pad module. The beZel
`performs a cosmetic function covering any gap betWeen the
`edge of the sensor surface and the surrounding plastic case.
`It also performs a necessary ergonomic function Which
`affects the quality of the user interface. If the beZel has
`appreciable depth, typically 0.5 mm to 1.0 mm, then it
`provides tactile feedback When the user’s ?nger has reached
`the edge of the sensor surface. In practice, systems designed
`Without a beZel are unsatisfactory because users do not
`notice When their ?ngers pass beyond the edge of the sensor
`surface causing the user to become confused When the
`pointing action unexpectedly stops. A practical design for a
`touch pad mounted in a palm rest or other suitable plastic
`case Will generally include some sort of beZel.
`To further appreciate the environment in Which the
`present invention is intended to occupy, reference is made to
`FIGS. 1 to 8 depicting prior art con?gurations. Speci?cally,
`FIG. 1 shoWs a notebook computer 10 as an example of a
`typical host electronic system. It is noted that touch pad 12
`is mounted in the palm rest, just beloW the space bar key of
`the keyboard. The sensor surface of the touch pad is con
`veniently accessible to the user and the control electronics
`are generally mounted on the hidden side of the touch pad
`module PC board.
`FIG. 2 shoWs a cross sectional vieW of a typical touch pad
`PC board. The sensor surface 13 is disposed on the top side
`of a printed circuit board 14. The sensor surface may be
`circuit board traces used as sensing electrodes, for capacitive
`touch pads, or may be a physically distinct sensor layer, as
`in resistive touch pads, adhered to the top surface of the
`circuit board. The circuit board is typically 1.8 mm to 2.0
`mm in thickness. The circuit board cannot practically be
`made thinner than about 1.4 mm or it Will ?ex perceptively
`under use When mounted as shoWn in FIG. 4, discussed
`beloW.
`The control electronics 16, shoWn in FIG. 2, are mounted
`on the underside of the printed circuit board. Some of the
`small discreet components, such as resistors and capacitors,
`are less than 0.5 mm in thickness. For the Synaptics standard
`touch pad module model TM 1202SPU, the thickness com
`ponent of the ?at ?exible cable connector, shoWn as element
`24 in FIG. 3, adds 2.9 mm to the module depth. Other
`components, such as the micro controller or sensor control
`IC, are betWeen 1.0 mm and 2.2 mm in thickness for each
`of the touch pads available from Synaptics, Alps and Log
`itech.
`FIG. 3 shoWs a plan vieW of the component side of a
`typical touch pad module, in this case, the Synaptics touch
`pad model TM 1202SPU. The components making up the
`control electronics include sensor controller ASIC 18, micro
`controller chip 20, the ceramic resonator 22, ?at ?exible
`cable connector 24 and various discreet components 26.
`Synaptics has speci?ed a keep-out Zone indicated by the
`dotted box 22.
`FIG. 4 shoWs the cross section of a palm rest incorporat
`ing a touch pad of the type shoWn in FIGS. 2 and 3. The palm
`
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`rest is typically composed of a plastic material such as ABS,
`betWeen 1.5 mm and 2 mm in thickness, shoWn as element
`28 therein. The palm rest is molded With an integral beZel
`opening 29 for touch pad module 30. Often, the palm rest
`Will include integrally-molded mounting brackets 32,
`designed to support the touch pad module and alloW it to be
`snapped from the underside of the case. Alternatively, the
`palm rest may provide for mounting screWs (not shoWn) or
`other means for securing the touch pad from behind. When
`mounted as shoWn in FIG. 4, the touch pad control elec
`tronics 34 and/or mounting brackets Will impinge from 2—5
`mm into the interior space of the host system. In many host
`systems, this impingement causes grave dif?culties. In some
`notebook computer systems, for example, the battery is
`placed directly beloW the palm rest. Since the control
`electronics protrude into the space in an irregular 3-D shape,
`the battery must be signi?cantly reduced in siZe in order to
`?t in the space available.
`Turning to FIG. 5, typical means by Which touch pad
`modules are connected electrically to their host systems is
`shoWn. Touch pad module 36 is shoWn component-side up
`for clarity. Usually, one end of a small ?at ?exible cable 38
`is inserted into a mating connector on the touch pad module
`36. The other end of the ?at ?exible cable is inserted into
`another mating connector in the host system (not shoWn).
`FIGS. 6 and 7 are directed to ?exible touch pad modules.
`Turning to FIG. 6, sensor surface 44 is disposed on one end
`of a rectangular ?exible circuit substrate 40 With control
`electronics 42 mounted on the underside of the other side.
`FIG. 7 shoWs a cross section of a typical installation of a
`?exible touch pad module in a palm rest. Palm rest 46 is
`molded With an integral depression 48 to support sensor
`surface 50 While a slot 52 through Which the ?exible sensor
`is passed during installation is provided. A thin adhesive
`layer is applied to supporting surface 48 Which holds sensor
`surface 50 in place. A suitable adhesive is available from
`3M. The control electronics 54 is located in another area of
`the palm rest Where there may be more clearance inside the
`host system. This con?guration may be useful in applica
`tions Where space is limited underneath the sensor surface
`but less limited elseWhere. It is to be noted that even though
`the sensor surface 50 itself is quite thin, on the order of 0.25
`mm, it still needs to be supported by a stiff backing plate 48.
`In general, this backing plate is no thinner than the PC board
`of a standard touch pad module as shoWn in FIGS. 2 and 3.
`It is apparent that the use of a ?exible touch pad module does
`not signi?cantly reduce the volume occupied by the touch
`pad module and its components; it only rearranges the space
`in a Way that may be bene?cial to some speci?c electronic
`device host system designs.
`FIG. 8 shoWs an alternative mounting arrangement for a
`touch pad Which is currently being developed by the
`assignee of the present application in conjunction With
`certain OEM customers. The touch pad sensor surface 50 is
`formed on a ?exible circuit substrate, such as Mylar or
`Kapton. The ?exible circuit only implements the touch pad
`sensor electrodes and does not include any of the control
`electronics. The touch pad control electronics 64 are
`mounted on the host system’s motherboard 60 or any other
`convenient circuit board already present in the host elec
`tronic device. The motherboard includes many other com
`ponents 62 not related to the operation of the touch pad. The
`?exible sensor surface is plugged into connector 66 mounted
`near and connected to the control electronics 64 on the
`motherboard. This mounting arrangement offers a very
`compact solution for the touch pad sensor surface Which can
`be mounted directly to the exterior of the palm rest. For host
`
`TCL EXHIBIT 1069
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`5,920,310
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`6
`rest according to the accepted means as shoWn in FIG. 4,
`there is a practical limit on hoW thin the PC board substrate
`can be. Notably, the board must be stiff enough to span the
`touch pad mounting hole in the palm rest Which is typically
`40 mm to 60 mm While being supported only by its edges
`and Without ?exing appreciably under hard use. To meet
`these requirements, a conventional PC board must be at least
`1.4 mm in thickness. The added 1 mm of the control
`electronics brings the overall touch pad module thickness to
`2.4 mm, not including the brackets or mounting hardWare
`needed to support the touch pad module from behind as
`shoWn, for example, as item 32 in FIG. 4. For many
`electronic devices, such a composite touch pad module is
`unacceptably thick.
`The assignee of the present application has also pursued
`?exible touch pad modules as a method for relieving space
`constraints in the area of the sensor surface. Such modules
`can be made as thin as 0.25 mm in the region of the sensor
`surface. This thin, ?exible sensor membrane can be applied
`directly to the exterior of the host system’s case and offers
`a minimal thickness solution. Such a system is shoWn in
`FIGS. 6 and 7. While ?exible touch pad modules satisfac
`torily address component clearance issues underneath the
`sensor surface, they have only really pushed the problem
`elseWhere. In the example shoWn in FIG. 7, the components
`have been relocated to the left of the sensor surface, not
`eliminated. In general, the solution may create as many
`problems as it solves.
`In addition to the above, ?exible touch pad modules are
`more difficult and expensive to manufacture. Kapton-based
`?exible printed circuits are tWo to four times as expensive as
`corresponding multi-layer PC boards per unit area, and the
`area required for the ?exible touch pad module shoWn in
`FIGS. 6 and 7 is roughly 2.5 times that of a standard touch
`pad module PC board. Multi-layer Mylar-based screen
`printed circuit boards are considerably less expensive than
`Kapton surfaces but the process of attaching electronic
`components to a Mylar circuit is rather expensive, not
`Widely available and less reliable than a standard printed
`circuit board assembly process.
`It is thus an object of the present invention to provide a
`relatively inexpensive touch pad module, With no reduction
`in performance over competing touch pad modules that take
`up the smallest possible amount of space in a host electronic
`device.
`This and further objects Will be more readily apparent
`When considering the folloWing disclosure and appended
`draWings.
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`systems Which can afford the space for the control electron
`ics on the motherboard, the solution offers excellent space
`utilization. HoWever, many systems cannot accommodate
`any amount of touch pad control electronics mounted on the
`motherboard Where space may already be scarce.
`Additionally, most OEM customers Would prefer to buy
`integrated touch pad modules rather than separate sensor
`surfaces and control electronics Which must be assembled
`and tested by the system integrator.
`As is quite apparent from the above discussion, the
`physical dimensions of a touch pad module are critical
`determinants of Whether a particular module can be
`employed in a host system. Historically, small siZe and, in
`particular, reduced thickness, has been a highly desirable
`feature of electronic components and subsystems. The
`relentless trend toWards more functionality in smaller and
`smaller systems is Well knoWn and represents an area of
`enormous expenditures of research and development effort
`on the part of electronic system integrators.
`Aparticularly space-constrained electronic product is the
`notebook computer. Users expect most of the functions of
`their desktop systems, including a large hard disk drive, a
`?oppy disk drive, a high resolution display, a usable
`keyboard, pointing device, memory, CD-ROM drive, stereo
`speakers, a large battery and more ?t into a space not much
`bigger than a desktop computer keyboard. As a
`consequence, touch pads have become the pointing device
`of choice in notebook computer systems, achieving a market
`share of 50% in less than tWo years, principally because they
`are thin. Touch pads displaced track balls because, among
`other reasons, notebook computer manufacturers could
`reduce the volume consumed by such pointing devices. This
`alloWed notebook computer manufacturers to provide users
`With longer battery life and/or additional functionality, like
`CD-ROM drives, by utiliZing the space previously occupied
`by the track ball. In the past year, the trend toWards very thin
`notebook computers has groWn stronger. Ultra-thin, light
`notebook computers, such as the IBM 560, have been
`Well-received by the market and such positive reception has
`encouraged all manufacturers to reduce thickness Wherever
`and Whenever possible.
`Several vendors of touch pad pointing devices, including
`Synaptics, Alps and Cirque, have responded to OEM cus
`tomer’s demand for thinner devices in various Ways. Syn
`aptics has offered a ?exible touch pad module, its TM3002,
`Which has been adopted by several notebook manufacturers.
`This device sells for roughly tWice the price of the corre
`sponding PC board-based standard touch pads and provides
`no additional functionality other than its reduced thickness
`in the area of the sensor surface. Demand for this product is
`groWing rapidly despite the strong price differential. Some
`companies, like Interlink Electronics, have introduced neW
`products into the marketplace by promoting reduced thick
`ness as their major competitive differentiation.
`In light of the strong demand, touch pad module manu
`facturers have sought a standardiZed design that Will provide
`customers With a manufacturable, inexpensive touch pads
`With no reduction in performance that takes up the smallest
`possible amount of space in the electronic host system. Prior
`to the present invention, vendors have explored several
`alternative means of making a thin touch pad module. One
`straightforWard idea Was to use the minimum thickness
`components available for the control electronics seeking to
`provide all necessary components in packages of no more
`than 1 mm in thickness. These thin components can be
`mounted on a reduced-thickness PC board. HoWever, if
`reduced-thickness touch pad modules are mounted in a palm
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`As noted previously, FIGS. 1 to 8 represent prior art
`depictions of a notebook computer (FIG. 1), touch pad
`modules (FIGS. 2, 3, 5, 6 and 8) as Well as cross sectional
`vieWs of such modules installed Within a suitable case
`material of a host electronic device (FIGS. 4 and 7).
`FIGS. 9a and b shoW side and plan vieWs, respectively, of
`a touch pad module produced pursuant to the present inven
`tion.
`FIG. 10 depicts, in side vieW, the module of FIGS. 9a and
`b supported by a portion of a case of a suitable electronic
`host device.
`FIG. 11 shoWs the con?guration of FIG. 10 in perspective
`vieW as the touch pad is applied to its supporting surface.
`FIG. 12 shoWs the underside of the touch pad module of
`the present invention together With a ?at ?exible cable for
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`7
`connecting the control electronics of the touch pad module
`to a surrounding host electronic device (not shoWn).
`FIG. 13 shoWs the touch pad module of the present
`invention in side vieW as a suitable ?at ?exible cable as
`being attached thereto.
`FIG. 14 shoWs the installation of the touch pad module
`With a suitable ?at ?exible cable connector of FIG. 13 to the
`side Wall of a suitable electronic device case.
`FIG. 15 shoWs the underside of an electronic device case
`in the region Where applicants touch pad module is to be
`installed including, as a preferred embodiment, a region for
`accepting and retaining the above-referenced ?at ?exible
`cable connector.
`FIG. 16 is a perspective vieW of the present invention
`shoWing the use of a beZel in conjunction With the applica
`tion of a touch pad module to the case of a suitable electronic
`host device.
`FIG. 17 is a side cross sectional vieW of the con?guration
`shoWn in FIG. 16.
`FIG. 18 is a cross sectional vieW of a preferred embodi
`ment of the present invention Wherein a resin is shoWn as
`adding structural integrity to the composite package.
`FIG. 19 is a perspective vieW of yet another embodiment
`Wherein a cap is shoWn also to add to the integrity of the
`overall structure.
`
`SUMMARY OF THE INVENTION
`
`The present invention deals With an electronic device
`having various internal parts Which makes use of a touch pad
`module to implement user input functions. The touch pad
`module comprises a preferably planar sensor surface having
`a length and Width for detecting the position of an object
`near or in contact With said sensor surface and control
`electronics Which electrically communicate said position
`information to said electronic device.
`The electronic device is provided With a case for housing
`its various internal parts, the case having a side Wall for
`mounting the above-referenced touch pad module. The side
`Wall of the case is provided With a region of thinner cross
`section than the remaining case side Wall Whereby the region
`of thinner cross section is of the approximate length and
`Width of the sensor surface. Within the region of thinner
`cross section is provided a through hole in the case for
`receiving the control electronics of the touch pad module,
`the through hole being of a siZe substantially smaller than
`the region of thinner cross section.
`
`10
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`15
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`20
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`25
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`30
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`35
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`40
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`45
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`DETAILED DESCRIPTION OF THE
`INVENTION
`
`55
`
`As noted above, the present invention is directed to a
`con?guration for arranging the physical components of a
`touch pad module and a method for mounting the module in
`the case of the suitable electronic device such that it pro
`trudes minimally, or not at all, into the interior volume of the
`host system. As noted above, FIG. 9 shoWs, in cross section,
`a thin conventional capacitive touch pad module formed
`from standard multi-layer printed circuit board 68 With
`control electronics 70 mounted on the reverse side from the
`60
`sensor surface. The printed circuit board 68 is only 0.5 mm
`in thickness Which is not rigid enough in and of itself to
`alloW the touch pad module to be mounted as shoWn in FIG.
`4. Signi?cantly, multi-layer circuit boards Which are less
`than 0.5 mm in thickness have become commonplace but, as
`noted previously, circuit boards Which are thinner than
`approximately 1.4 mm cannot be mounted as shoWn in FIG.
`
`65
`
`5,920,310
`
`8
`4 for they Will ?ex perceptively under use When ?nger or
`stylus pressure is applied thereto.
`FIG. 9a shoWs, in plan vieW, the component side of
`applicant’s thin touch pad module. All of the control elec
`tronics 74 are selected to use the thinnest available packages
`and all of the components are ideally clustered as tightly as
`possible near the center of circuit board 72. As illustrative of
`this concept, applicant has produced a capacitive touch pad
`mounting all necessary components Within a rectangle 28
`mm by 21 mm in siZe. Instead of a thick ?at ?exible cable
`connector, a pattern of exposed, solderable pad 76 is also
`clustered near the center of the board to provide for electrical
`connection to the electronic host device.
`FIG. 10 shoWs hoW applicant’s touch pad module 80 is
`mounted on a suitable device case, such as on the palm rest
`of a notebook computer. Palm rest material 78, typically 1.5
`mm to 2 mm in thickness is molded With recess 79 deep
`enough and large enough to accommodate a thin touch pad
`module circuit board Which is generally about 50 mm by 6
`mm by 0.6 mm. An important aspect of the present invention
`is to provide through hole 84 either molded or cut into region
`of thinner cross section 90 (FIG. 11) Which is large enough
`to accept control electronics 82 and the above-recited con
`nection pads. When thin touch pad module 80 is mounted as
`shoWn, the region of thinner cross section 90 Will be
`approximately 1.3 mm in thickness noting that this region
`has been produced by reducing the case side Wall of 2 mm
`by providing a recess of approximately 0.7 mm. If the tallest
`of the touch pad module control electronics components is
`1 mm, none of the control electronics Will protrude at all into
`the host electronic device’s interior space.
`FIG. 11 shoWs an exploded perspective vieW of the
`con?guration shoWn in FIG. 10. Again, there is a region of
`thinner cross section 90 formed Within case material 92 large
`enough and deep enough to accommodate the touch pad
`module circuit board. Through hole 94 is large enough to
`accommodate the touch pad module control electronics 88
`mounted on the underside of the circuit board. A thin touch
`pad module 86 can be af?xed to region 92 by applying a very
`thin layer of adhesive to the interior of region of thinner
`cross section 90 or, alternatively, to the exposed area of the
`underside of the touch pad PC board.
`Since the ?at ?exible cable mating connector used in most
`standard touch pad modules is so thick, it is desirable to
`eliminate it entirely in the thin touch pad design of the
`present invention. In this regard, FIGS. 12 and 13 shoW hoW
`a ?at ?exible cable can be directly attached to the surface of
`the touch pad module Without the use of a bulky connector.
`Speci?cally, FIG. 12 shoWs a thin touch pad module 96
`shoWn component side up for clarity. The exposed connector
`pads 100 arranged so that their spacing matches the spacing
`of the conductors on a suitable ?at ?exible cable 102,
`typically 1.0 mm center to center. Control electronics 98 are
`shoWn for reference.
`FIG. 13 shoWs the same thin touch pad module 106 in
`cross section. Control electronics 108 are soldered to the
`printed circuit board using standard surface-mount technol
`ogy techniques. Exposed conductors 112 of the ?at ?exible
`cable 104 are soldered directly to the touch pad’s connection
`pads