United States Patent [191
`DePauli
`
`[11]
`
`[45]
`
`Patent Number:
`Date of Patent:
`
`4,963,793
`* Oct. 16, 1990
`
`[54] DELAYED RESPONSE TOUCH SWITCH
`CONTROLLER
`Inventor:
`John F. DePauli, San Diego, Calif.
`[75]
`[73] Assignee: Westek Associates, San Diego, Calif.
`[ *] Notice:
`
`The portion of the term of this patent
`subsequent to Jul. 3, 2007 has been
`disclaimed.
`[21] Appl. No.: 165,591
`[22] Filed:
`Mar. 8, 1988
`
`[56]
`
`Related U.S. Application Data
`[63]
`Continuation-in-part ofSer. No. 148,767, Jan. 26, 1988.
`Int. a.s ........................ H01J 7/66; H05B 37/02;
`[51]
`H05B 41/04
`[52] u.s. a ....................................... 315/74; 315/291;
`315/DICi. 4; 315/360; 315/362
`[58] Field of Search .................. 307/116, 114; 315/74,
`315/291, 194, 199, om. 4, 362, 360
`References Cited
`U.S. PATENT DOCUMENTS
`4,160,192 7/1979 McAllise ......................... 315/360 X
`4,359,670 11/1982 Hosakia eta!. ..................... 315/307
`4,508,997 4/1985 Woodnutt ........................... 315/360
`4,649,323 3/1987 Pearlman et al .................... 315/307
`Primary Examiner-Eugene R. Laroche
`Assistant Examiner-Ali Neyzari
`Attorney, Agent, or Firm-Brown, Martin, Haller &
`McClain
`
`ABSTRACT
`[57]
`The present invention provides a very low actuation
`force touch control switch for use in brightness control
`of illumination devices. The control switch comprises a
`flexible membrane having a plurality of conductors
`disposed on one surface and secured to a rigid support
`surface. The conductors are interwoven in a present
`pattern with portions of the conductors being exposed.
`A conductive surface is formed in an area under the
`exposed conductors. The membrane is fastened to the
`rigid support surface so that a very small spacing is
`maintained between the exposed conductors and the
`fixed conductive surface, allowing a very light touch to
`cause one or more exposed conductors to be shorted to
`the conductive surface. A microprocessor periodically
`polls the leads of the membrane to determine which are
`shorted together and causes an output power level to be
`adjusted accordingly. The touch control system em(cid:173)
`ploys a Delayed-Off feature in which the microproces(cid:173)
`sor causes a discernible dimming to occur when a
`DELAYED-OFF selection are on the memberane is
`pressed but which delays the turning off of the illumina(cid:173)
`tion device until a preselected amount of time has
`passed, thereby allowing a switch operator to leave an
`area before becoming dark. In addition, Soft-On and
`Soft-Off processing is employed so that on and off tran(cid:173)
`sitions are more gradual and aesthetically pleasing and
`to provide a period in which to select an alternate
`brightness level.
`
`20 Qaims, 4 Drawing Sheets
`
`4 - r ·
`
`2
`
`_ _j
`
`6
`
`24
`
`vss
`IRQ
`vee
`EXTAL
`XTAL
`MDS
`TIMER
`PeO
`Pel
`Pe2
`PC3
`
`PA6
`PA5
`PA4
`PA3
`PA2
`PAl
`PAO
`PB7 .
`
`~ 30
`
`MID
`L6
`L5
`L4
`L3
`L2
`Ll
`LOW
`DIM
`
`14
`
`12
`
`- - - - -
`
`_j
`
`MICROSOFT EXHIBIT 1008
`
`

`
`,r20 LJ=1
`RESET ~ 30
`
`PA7
`
`HIGH
`MID
`L6
`L5
`L4
`L3
`L2
`Ll
`LOW
`DIM I
`
`PA6
`PA5
`PA4
`PA3
`PA2
`PAl
`PAO
`PB7
`PB6
`PB5 1--
`PB4 1--
`PB3 1--
`
`4 - r ·
`
`2
`
`I
`
`+5V
`N/
`
`26
`
`I ~ 624
`_ _j
`
`J vss
`
`IRQ
`vee
`EXTAL
`XTAL
`MDS
`TIMER
`
`~~~
`
`N/e
`
`Pe3
`r-1PBO
`PBI
`PB2
`
`22
`
`I
`
`+5V I
`14
`12~T
`
`18
`
`L.
`
`-
`
`FIG. I
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`jooool
`
`~
`i
`Sa
`....
`,. -...
`\C
`~
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`~
`
`

`
`U.S. Patent Oct. 16, 1990
`34 32
`38-- ,- -
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`I
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`Sheet 2 of 4
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`~,963,793
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`FIG. 2
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`36
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`
`lflHIGH
`3~
`MID -~ ~
`
`L2 L4
`
`31
`
`31
`
`40
`
`34
`
`FIG.3
`
`FIG.4
`
`FIG.5
`
`

`
`U.S. Patent
`
`oct. 16, 1990
`
`Sheet 3 of 4
`
`4,963,793
`
`7
`
`-f-
`
`7
`
`-i
`
`46
`
`44 42
`
`~&SLS~''".!,Jss,
`FIG. 7
`
`FIG. 6
`
`40
`
`-
`
`FIG. 8
`
`~0
`
`FIG. 9
`
`

`
`U.S. Patent
`
`Oct. 16, 1990
`
`Sheet 4 of 4
`
`4,963,793
`
`DECREASE
`BRIGHTNESS
`LEVEL
`
`STORE BLEVEL
`AS
`ENTRY LEVEL
`
`CLEAR
`SOFT OFF
`FLAG
`
`NO
`
`NO
`
`TRIGGER
`TRIAC/
`SWITCH
`
`FIG.IO
`
`

`
`1
`
`4,963,793
`
`DELAYED RESPONSE TOUCH SWITCH
`CONTROLLER
`
`CROSS REFERENCE TO RELATED
`APPLICATIONS
`The present application is a continuation in part of
`application Ser. No. 148,767 filed on Jan. 26, 1988.
`
`40
`
`2
`SUMMARY OF THE INVENTION
`One purpose of the present invention is to provide a
`touch sensitive controller that allows a delayed off
`5 response.
`Another purpose of the present invention is to pro(cid:173)
`vide a touch control switching system that allows ready
`adjustment or reinstatement of illumination levels after
`a an off command.
`An advantage of the present invention is the provi(cid:173)
`sion for a period of partial illumination after receiving
`an off command to allow safe exit from a lighted area.
`Another advantage of the prevent invention is the
`provision of easy reactivation of the illumination pat(cid:173)
`tern after requesting an off state.
`The present invention provides a touch control sys(cid:173)
`tem which is actuable by a very light touch while allow(cid:173)
`ing a large number of switching gradations or control
`sequences.
`These and other purposes, advantages, and objects of
`the present invention are realized if a touch control
`system comprising a pad with multiple interleaved con(cid:173)
`ductors disposed on a semi-flexible material which is
`generally mounted on a very rigid base or support struc(cid:173)
`ture. The semi-flexible membrane is attached directly to
`the rigid base with a thin layer of adhesive which serves
`as a spacer, leaving portions of the interleaved conduc(cid:173)
`tors exposed. The rigid base has a recessed portion in
`which a conductive element is mounted and positioned
`so that it is directly beneath exposed portions of the
`conductors printed on the semi-flexible membrane. Be-
`cause of the extremely small spacing between the mem(cid:173)
`brane and the rigid base and because of the rigidity of
`the base, a very light touch causes exposed conductors
`to come in contact with the conductive element, short(cid:173)
`ing them together. Because of the extremely small spac-
`ing provided by this construction technique, an ex(cid:173)
`tremely light touch is required to actuate the switch
`rendering it far more aesthetically pleasing and more
`suitable for use in many applications.
`In one embodiment of the invention, a precision re(cid:173)
`cess is molded into a rigid plastic base, which precisely
`accommodates the thickness of a hot-stamped or print-
`ed-on conductor. The interleaved conductors are
`mounted above this conductor and constantly polled or
`monitored by a microprocessor to determine which are
`shorted together. The microprocessor provides a con(cid:173)
`trol signal to a triac which alters an controlled output
`power level according to which conductors are shorted
`together. Using lithographic techniques to form the
`conductors, a complex pattern of interleaving can be
`achieved and a large number of gradations created and
`nearly continuous power control may be provided.
`A Delayed-Off feature is implemented by interleav(cid:173)
`ing at least two of the conductors in a DELA YEO(cid:173)
`OFF selection area on the flexible membrane and using
`conduction between these conductors to initiate a de-
`layed response tum off operation. When the Delayed(cid:173)
`Off mode is initiated by touch contact, the power out(cid:173)
`put level is immediately decreased, dimming any con(cid:173)
`trolled light, to indicate to the user that the Delayed-Off
`has taken effect. The microprocessor holds this power
`level and counts a fixed period oftime before turning off
`the lamp. Thus, a person has time to leave the room
`before the room goes dark.
`In addition, the microprocessor utilizes a short period
`decreasing power level ramp to tum off illumination
`devices connected to the controller.
`
`10
`
`20
`
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`The present invention relates to electrical switches
`and controllers and more particularly to a touch actu(cid:173)
`ated switching system that provides delayed response 15
`timing for termination of electrical power to a con(cid:173)
`trolled device. The invention further relates to a touch
`control system allowing selection between a plurality of
`alternate ON states, an OFF state, and a delayed OFF
`state for an illumination device.
`2. Background of the Art
`Touch control switching systems, especially for con(cid:173)
`trolling illumination devices, have proven appealing
`due to their added convenience and aesthetics. How(cid:173)
`ever, incorporation of multiple power level dimming 25
`schemes in such systems or switches has typically re(cid:173)
`quired use of complex touch or contact sequences
`which have proven annoying or to difficult to remem(cid:173)
`ber and use for noncommercial applications.
`To decrease the operational complexity by decreas- 30
`ing the number of discrete contact elements that must
`be separately touched during operation, a class of
`switches based on membrane contacts were developed.
`In membrane switching a series of switch contact is are
`manufactured on the surfaces of one or more adjacent 35
`membranes which are deformed into contact by touch.
`This allows a series of contact elements or patterns to be
`built into a relatively compact structure which is oper(cid:173)
`ated by touching an exterior surface which generally
`hides the underlying contact structure. A variety of
`otherwise complex power or lighting level control
`schemes are accommodated through a specific, and
`complex, interconnection of contacts without requiring
`knowledge by the switching system user. The user only 45
`needs to follow a simple contact pattern on an exterior
`surface which is interpreted by the more complex un(cid:173)
`derlying pattern of switch contacts.
`However, present membrane switching techniques
`have a number of drawbacks which seriously limit their 50
`suitability for many applications. One drawback is a
`requirement for relatively high actuation forces which
`reduces their aesthetic appeal and their utility for users
`having limited hand or fmger mobility or strength. A
`second drawback is the generally complex multi-lay- 55
`ered construction techniques for present membrane
`switches which adds to their cost and complexity.
`At the same time, an inadequacy of all prior tech(cid:173)
`niques for switching lights is that switching systems
`automatically turn lights completely off before a system 60
`user can leave the room or building. Thus, the user must
`fumble in the dark to leave the previously illuminated
`area or leave a light on.
`What is needed is a method and apparatus for proving
`touch actuated control over the brightness or light out- 65
`put of lamps or similar illumination devices that is easy
`to use and provides a more convenient output scenario
`when adjusting to an off state.
`
`

`
`4,963,793
`
`6;
`
`4
`3
`lamp 2. The interface plug 1 is generally polarized with
`BRIEF DESCRIPTION OF THE ORA WINGS
`one contact blade oriented to connect to a neutral or
`grounded side of the electrical source 5 and a second
`The novel features of the present invention may be
`blade connected to a hot side. Electricity from the neu-
`better understood from the accompanying description
`when taken in conjunction. with the accompanying 5 tral or grounded side is connected directly to both a
`first input of the controlled lamp 2 and a control circuit
`drawings in which like characters refer to like parts and
`in which:
`or controller 4. The second or hot side of the electrical
`FIG. 1 illustrates a schematic diagram of control
`source 5 output is connected to a second input of the
`circuitry used in one embodiment of the present inven-
`control circuit 4 which is in turn connected to a second
`tion;
`10 electrical input of the controlled lamp 2.
`FIG. 2 illustrates a schematic pattern for conductors
`As shown in FIG. 1, the control circuit 4 uses a triac
`used on a membrane in a touch control switch con-
`6 interposed between the second electrical source con-
`nection and the controlled lamp 2. A microprocessor 20
`structed according to the present invention;
`FIG. 3 is an enlarged sectional view taken on line
`is used in the control circuit 4 to determine the various
`3-3 of FIG. 2;
`15 operating levels for the lamp 2 and provide control
`FIG. 4 is an enlarged sectional view taken on line
`signals to the triac 6.
`4-4 of FIG. 2;
`An exemplary microprocessor 20 useful in construct-
`FIG. 5 is a view of the rear face of membrane 30 of
`ing the present invention is a microprocessor manufac-
`FIG. 2;
`tured by the Motorola Company under the designation
`FIG. 6 is a top plan view of the base for membrane 30 20 of model numbers 6804, HC 6804 or 68HC6804. This
`of FIG. 2;
`processor has the advantage that it is a low power
`FIG. 7 is a sectional view taken on line 7-7 of FIG.
`CMOS type device which is organized as an eight-bit
`central processor with an internal instruction set that
`efficiently handles the required control functions or
`FIG. 8 is an enlarged sectional view similar to FIG. 7,
`25 instructions of the present invention.
`with membrane 30 attached;
`FIG. 9 is a view similar to FIG. 8, showing the
`Of course, the exact microprocessor used and the
`operating frequency and port configurations may be
`contact action; and
`altered so long as required operating programming is
`FIG. 10 illustrates a flow diagram of the steps em-
`provided. The exemplary HC6804 microprocessor em-
`played by the control circuitry of FIG. 1.
`DETAILED DESCRIPTION OF A PREFERRED 30 ploys a series of internal storage registers, an accumula-
`EMBODIMENT
`tor, an internal timer, ROM type memory, and 32-128
`bytes of RAM which are available in other micro(cid:173)
`processors. However, the present invention only re(cid:173)
`quires a few hundred bytes of ROM to implement along
`with 4-8 internal registers, a timer, an accumulator and
`associated support elements, allowing less complex
`microprocessors to be employed. In the alternative, an
`Application Specific Integrated Circuit (ASIC) is con(cid:173)
`structed which incorporates only the specillc amount of
`ROM, RAM, and other elements, including discrete
`components like timing capacitor 26 (see below). The
`manufacture of an ASIC reduces cost through reduced
`complexity and may require less power to operate.
`The microprocessor 20 operates in five volt electrical
`power which is typically derived from the 110 volt
`input through a diode 8, resistor 10, zener, diode 12 and
`capacitor 14. The diode 8 supplies semi-rectified current
`which is limited by a the resistor 10 which has a resis(cid:173)
`tance of approximately 10 kilo-ohms. A zener diode 12,
`with a zener breakdown voltage of approximately 5
`volts, is connected between the output of the resistor 10
`and ground and clamps the voltage between a power
`supply point 16 and ground point 18 to 5 volts.
`The capacitor 14 has a capacitance of approXimately
`200 microfarads which acts to smooth out the semi(cid:173)
`sinusoidal signal provided through the diode 8 which
`provides a fairly high quality or well regulated positive
`5 volt supply voltage to power supply node 16. Because
`the ground 18 is connected to the other side of at 110
`volt power supply voltage, power supply node 16 floats
`at 5 volts above the nominal 110 volts AC power from
`the electrical source 5.
`In the preferred embodiment, power supply voltage
`is also provided to microprocessor 20 through a resistor
`22 to all four input terminals of port C (labeled
`PCO-PC3) of the exemplary microprocessor 20. The
`resistance of the resistor 22 is approximately 1 meghms,
`which limits the current to a value which will not dam-
`
`The present invention provides a touch control
`switch or power controller that provides several adjust(cid:173)
`able levels of output power to a controlled device such 35
`as a lamp or other source of illumination and allows a
`time delayed response to OFF commands. In addition,
`during execution of OFF commands the illumination
`device is ramped to a zero power level over a short
`period rather than abruptly turned off. These steps are 40
`accomplished if a touch control switch assembly em(cid:173)
`ploying a low activation force switch with a series of
`patterned conductors positioned above a conductive
`surface. The conductors are connected to a control
`circuit for monitoring conduction between the conduc- 45
`tors and providing an output control signal to an output
`power device in response to conduction patterns or
`sequences.
`A schematic diagram depicting control circuitry con(cid:173)
`structed and operating according to the principles of 50
`the present invention is illustrated in FIG. 1. In FIG. 1,
`a controller is shown having an interface plug 1 con(cid:173)
`nected between a lamp 2, or other illumination device,
`and a source of electricity 5 such as a typical wall or
`floor outlet (not shown).
`A typical application for the present invention is for
`controlling the brightness of household lamps and light(cid:173)
`ing fixtures operating at 110 volts AC. Therefore, the
`electrical source 5 is described as providing 110 volt
`AC current at approximately 60 Hertz which is stan- 60
`dard household voltage and frequency in the United
`States. However, the method of the invention is also
`applicable to other voltage levels up to 220 volts and
`operating frequencies such as 50 Hertz with adjust(cid:173)
`ments to components as would be obvious to those 65
`skilled in the art.
`The interface plug 1 is configured to act as a recepta(cid:173)
`cle for a matching electrical plug (not shown) for the
`
`55
`
`

`
`4,963,793
`
`20
`
`5
`age microprocessor 20. Integrated circuits generally
`contain voltage protection diodes which clamp input
`voltages above Vee to Vee+ 1.6 volts on the internal
`circuitry of the integrated circuit and similarly with
`voltages below 0 volts the voltage supplied to the inte- 5
`grated circuit is clamped to Vss -1.6 volts. Because of
`the input protection devices, what microprocessor 20
`actually sees is a square wave input going from nomi(cid:173)
`nally 0 to 5 volts.
`Microprocessor 20 controls the operation of triac 6 10
`through capacitor 24. During periods when triac 6 is
`off, output terminals P80 through P85 are maintained at
`a high, I, logic level, i.e., 5 volts. When microprocessor
`20 is to turn on triac 6, output terminals P80 through
`P85 go to a low, 0, logic level, i.e. 0 volts. The charge 15
`stored on the capacitor 24 is discharged into a P-type
`injection port of triac 6 which causes triac 6 to turn on.
`Output ports PBO through PBS then return to the high
`or 5 volt level and the capacitor 24 is recharged by
`internal leakage through the triac 6.
`The capacitor 26 adjusts or sets the operating fre(cid:173)
`quency of microprocessor 20. The microprocessor 20
`has an internal clock generation circuit whose operating
`frequency is adjusted by an external capacitor.
`A capacitor 28 is connected to the reset input termi- 25
`nal to prevent stray fields from generating a reset signal
`in the microprocessor 20.
`Microprocessor
`terminals PB6, PB7 and P AO
`through PA7 are connected to a series of dim, low, L1
`through 6, mid and high leads of a touch switch 30. A 30
`layout of a membrane portion of the touch switch 30 is
`shown in FIG. 2. As shown in FIG. 2, the dim, low, mid
`and high leads of the switch 30 cross a power level
`control area 40 covering 4 sections of dimmer area 40.
`Leads L1 through L6 interweave through the dim, low, 35
`mid, and high leads in a serpentine fashion. The dim
`lead is interwoven with the high lead in an OFF selec(cid:173)
`tion area 38 and the low and high leads are interwoven
`in a DELA YEO-OFF selection area 36. A printed
`insulator 34 covers all leads excepting in areas 36, 38 40
`and 40. In these areas the leads are exposed.
`FIG. 3 is a sectional view of membrane 30 showing
`the exposed low, dim and high leads. These leads are
`supported by substrate 31 but are not covered by insula(cid:173)
`tion 34 in this selection area. FIG. 4 is a section ofmem- 45
`brane 30 taken along line 4-4 of FIG. 2. FIG. 4 shows
`how leads L1 through L4 and the high lead are insu(cid:173)
`lated by insulation 34 but lead HIGH is exposed in
`opening 40. FIG. 5 is a rear view of membrane 30
`through substrate 31.
`FIG. 6 is a top view of base 42. Recess 44 is a flat
`recess approximately 2 mils below the flat surface of
`base 42. Conductor area 46 is formed in recess 44. In a
`preferred embodiment conductor 46 is formed by car(cid:173)
`bonized paint. Conductors 50 and 52 are formed in a 55
`simi)ar manner. Ventilation hole 48 is included to avoid
`alteration of the tolerances between membrane 30 (FIG.
`2) and base 42 due to variations in ambient temperature
`and/or barometric pressure changes when membrane
`30 is adhesively placed on the surface of base 42.
`FIG. 7 is a side view of base 42 and conductor 46.
`FIG. 8 is a side view showing membrane 30 attached
`to base 42 by adhesive 43. Because of the extreme rigid(cid:173)
`ity of base 42, which is preferably formed with high
`rigidity plastic, this spacing tolerance between the ex- 65
`posed leads of membrane 30 and conductor regions 46,
`50 and 52 can be very small on the order of 50 microns
`or less. Because of this small tolerance, a very light
`
`6
`touch approximately one half ounce, is required to
`cause connection between the leads formed on mem(cid:173)
`brane 30 and conductor regions 46, 50 and 52. Because
`of this tight tolerance, membrane 30 must be formed of
`a plastic such as mylar which is resistant to moisture and
`temperature alterations of size and shape and membrane
`30 must be fastened to the surface of base 42 using an
`adhesive 43 such as the 467 adhesive by 3M Corpora(cid:173)
`tion which is also moisture and temperature stable.
`In the described embodiment, adhesive 43 acts as a
`spacer between membrane 30 and base 42 to provide
`precise spacing between membrane 30 and conductor
`regions 46, 50 and 52. Alternatively, adhesive 43 is
`made thicker, approximately 7 mils, and recess 44 is
`eliminated. In this alternative embodiment, the adhesive
`itself provides all the required spacing between the
`conductors of membrane 30 and conductor regions 46,
`50 and 52.
`To activate the touch control switch of the present
`invention and select an illumination Setting, manual
`pressure is applied on the top of the membrane 30.
`When pressure is directed on the membrane 30 above
`conductor region 46, as shown in FIG. 9, one or more
`of the leads L1 through L6 will be shorted to one of
`more of dim, low, mid and high leads through conduc(cid:173)
`tor 46. Microprocessor 20 is programmed so that a
`logical 0 is placed on each of the dim, low, mid and high
`leads, successively and leads L1 through L6 are nor-
`mally at a logicall. Microprocessor 20 then polls termi(cid:173)
`nals P AO through PAS to determine if conductivity is
`present between the selected dim, low, mid and high
`lead and one of the leads L1 through L6. If continuity is
`found, that fact is stored in a register within micro-
`processor 20 and is used as timing data for triggering the
`triac 6.
`The controller 4 and, thus, the microprocessor 20 are
`powered on as long as the interface plug 1 is connected
`to an electrical source 5. To preserve aesthetics no
`separate ON switch is used, although possible. This
`means that the controller 4 is always ready to receive
`new commands or brightness level requests from the
`switch membrane 30, subject to polling timing de(cid:173)
`scribed below.
`The operation of the microprocessor 20 and associ(cid:173)
`ated support elements and leads low through high are
`better understood from viewing the flow diagram of
`FIG. 10 in conjunction with the circuit of FIG. 1.
`The microprocessor 20 is initialized or initializes the
`50 controller 4 on initial power up so that the microproces(cid:173)
`sor port A leads PAO-PAS, port B leads PB6-PB7 and
`port C leads PCO-PC3 are set or configured as inputs;
`and port A leads PA6-PA7, and port B leads PBO-PBS
`are set as outputs, except for polling commands as used
`below. The voltage on the PCO-PC3leads, from regis(cid:173)
`ter 22, are defmed as high and the PB1-PB5 and PA6--
`p A 7 leads set at a high or 1 logic level. A system status
`register is loaded with a multi-bit command which con(cid:173)
`tains bits defming system status for certain basic operat-
`60 ing parameters. These parameters are lamp ON or OFF,
`Soft-On feature active or inactive, polarity for the triac
`6 (low positive, high negative), Delayed-Off active or
`inactive, and Soft-Off inactive or active. Initially these
`values are set as OFF, inactive, low, inactive, and inac(cid:173)
`tive.
`Additional registers, such as a register BLevel are set
`for establishing an initial Brightness Level. The BLevel
`register is initially loaded with a value on the order of
`
`

`
`4,963,793
`
`25
`
`7
`5.6 milliseconds of delay. The BLevel register value is
`also loaded into a Timer Counter Register TCR.
`As the line voltage connected to plug 1 passes
`through one half cycle of the sinusoidal alternating
`current provided by the electrical source, microproces- 5
`sor 20 (FIG. 1) detects zero voltage cross over transi(cid:173)
`tions through input terminals PCO through PC3. These
`cross over points are used as markers or flags to prompt
`a processing cycle for the microprocessor 20 operating
`instructions or program.
`The operating frequency of microprocessor 20 is
`approximately 125 kilohertz which is approximately
`2000 times the operating frequency of standard house(cid:173)
`hold current. The exemplary HC 6804 microprocessor
`requires on average four clock cycles to perform a 15
`given command or instruction. Therefore, the micro(cid:173)
`processor 20 executes approximately 500 instructions
`for every cycle of the power source 5 and approxi(cid:173)
`mately 250 instructions every one-half cycle. The one(cid:173)
`half cycle period representing the time between zero 20
`voltage cross over points for the sinusoidal AC current
`source. As before, the value of capacitor 26 can be
`altered to establish an alternate timing cycle for the
`microprocessor 20 where other electrical sources are
`used.
`During a given half-cycle, the longer triac 6 remains
`off, the lower the average power received by lamp 2
`and the dimmer the lamp 2 will be. Conversely, the
`longer the lamp 2 is turned on the brighter it will be.
`Thus, when the microprocessor 20 is set to provide a 30
`particular brightness setting, microprocessor 20 adjusts
`the amount of delay time that passes into each half-cycle
`before the triac 6 is turned on. The lowest intensity or
`brightness setting typically translates to about 6. 7 milli(cid:173)
`seconds of delay before allowing triac 6 to tum on and 35
`at the brightest setting, microprocessor 20 allows triac 6
`to turn on about 1.6 milliseconds after the start of a half
`cycle. This 1.6 millisecond delay is used to allow micro(cid:173)
`processor 20 to poll the required leads of membrane 30
`to determine if a new setting or brightness has been 40
`selected and perform necessary program steps.
`At the start of each half cycle or 1.6 millisecond delay
`period, the microprocessor 20 begins operation by pull(cid:173)
`ing or strobing the P A 7 lead low to poll the various
`input leads and determine their conductivity with 45
`P A07. The microprocessor 20 also starts an internal
`timer which is used to set the firing time for the triac 6.
`With the P A 7 lead pulled low, the touch pad is
`checked for brightness commands by checking one
`level of each of the leads P AO-PS one at a time. If any 50
`of the leads are in a low state then a time delay value
`associated with that lead is loaded into the BLevel reg(cid:173)
`ister. For the preferred embodiment, the levels associ(cid:173)
`ated with conductivity between lead PA7 and the PA-
`0-AS leads is on the order of 2.0, 3.0, 3.2, 3.4, 3.5, and 55
`3.6 milliseconds respectively. The microprocessor 20
`then sets the P A 7 lead high and the P A6 lead is strobed
`low. The PAS-PAO leads are again checked, this time in
`descending order, and another series of associated val(cid:173)
`ues loaded into the BLevel register. These values are 60
`3.7, 3.8, 3.9, 4.0, 4.1, and 4.2 milliseconds respectively.
`Note that the lowest or smallest delay values are
`checked fust so that the brightest setting specilled by
`touching the touch pad is selected first to the exclusion
`of other or contradictory commands during a given 65
`polling cycle. Once a brightness level is selected and
`loaded into the BLevel register a new brightness level
`cannot be selected until the next cross over point.
`
`8
`The above procedure is used with leads PB6 and PB7
`by setting them as outputs and strobing them to a low
`value and checking the leads PAl-PAS and then PAS-(cid:173)
`PAl respectively. The values loaded into the BLevel
`register when these leads are detected as low are 4.3,
`4.4, 4.5, 4.6, 4.7, 4.8, 4.8, 4.9, 5.0, 5.1, 5.2, and 5.3 milli-
`seconds respectively.
`The microprocessor 20 then changes or sets the
`PB6-PB7 leads to inputs with the P A 7 lead then
`10 strobed low. The leads PB7 and PB6 are checked to
`determine if contact has been made in the OFF selection
`area 36 or DELAYED-OFF selection area 38.
`Of the 26 combinations between the dim, low, mid,
`and high leads, and the leads L1 through L6 on the
`membrane 30, twenty-four are used to defme gradations
`or levels of brightness for the lamp 2 and two are used
`to define "OFF' and "DELAY-OFF" states or com(cid:173)
`mands. The differences in brightness between adjacent
`levels are very difficult to perceive by the human eye,
`thus the variations in levels appear to be a continuous
`scale. Because of the light touch and the continuous
`scale appearance of the control switching system, the
`described embodiment provides a lamp dimming system
`with the tactile qualities of touch lamp control and the
`aesthetic qualities of continuous dimming.
`The microprocessor 20 continues to monitor or poll
`the leads PAO-PAS on a periodic basis and detects any
`new commands or requests for altered brightness. If a
`new level command is detected then a value for the
`corresponding delay from zero point cross over is trans(cid:173)
`ferred into the BLevel register which is used to deter-
`mine the timing for flring the triac 6.
`While the variations in brightness as implemented by
`the present invention advance the art, additional fea(cid:173)
`tures are provided by the method and apparatus of the
`invention which prove most useful.
`One such feature is the implementation of a Soft-Start
`technique for initially turning on the lamp 2 after being
`turned off. In the Soft-Start or Sott-On mode of opera(cid:173)
`tion the microprocessor 20 retrieves the current bright(cid:173)
`ness level from the BLevel register and saves it in a
`temporary Command Level (ComLevel) storage regis(cid:173)
`ter. The ComLevel value, from the BLevel register, is
`used as a target brightness level unless the touch control
`user sets a new level. The target level is adjusted if a
`different one is requested by a control user before the
`ComLevel value is reached.
`Typically the BLevel value is then set at a very low
`level, say on the order of 5.6 milliseconds of delay as set
`initially in the BLevel register. This means that the
`initial average power delivered to the lamp 2 is very
`low which results in a dim light level. The BLevel value
`or number is then decreased by subtracting 32 microsec(cid:173)
`onds from the BLevel register value and reloading the
`new value into the BLevel register on each micro(cid:173)
`processor 20 instruction cycle. At the beginning of each
`microprocessor instruction cycle the new BLevel value
`is compared to the value stored in ComLevel to see if
`the target level has been reached. If it has, Soft-On
`processing is completed. Otherwise, the Soft-On pro(cid:173)
`cessing continues until completed, and does so to the
`exclusion of other level changes or commands. Once
`the microprocessor 20 has adjusted the triac 6 to
`achieve the desired brightness level, the appropriate bit
`in the system status register is set low to indicate that
`the Soft-on processing routine i