United States Patent (19)
`Koziuk et al.
`
`54 METHOD AND APPARATUS FOR
`MANAGING POWER CONSUMPTION OFA
`DIGITIZING PANEL
`
`75 Inventors:
`
`r.
`sets Mark s Snyder, both
`le
`OI Colorado SpringS, UOIO.
`73 Assignee: LSI Logic Corporation, Milpitas,
`Calif.
`
`21 Appl. No.: 08/902,146
`1-1.
`22 Filed:
`Jul. 29, 1997
`(51) Int. Cl." ........................................................ G06F 1/32
`52 U.S. Cl. .......................... 713/320; 713/323; 713/340;
`345/173
`58 Field of Search ..................................... 713/320, 323,
`713/321,340; 345173
`s
`s
`
`56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`1/1983 Gaudio .................................... 7
`4,370,733
`4,787,040 11/1988 Ames et al. ................................ 7011
`4,972,496 11/1990 Sklarew ...........
`... 382/187
`5,329,625
`7/1994 Kannan et al. ......................... 395/275
`
`US0060584.85A
`Patent Number:
`11
`(45) Date of Patent:
`
`6,058,485
`9
`9
`May 2, 2000
`
`5,396,443 3/1995 Mese et al. ............................. 364/707
`5,423,045 6/1995 Kannan et al. ......................... 395/750
`5,524.249 6/1996 Suboh ..................................... 395/750
`5,548,765 8/1996 Tsunoda et al. ........................ 395/750
`5,553,296 9/1996 Forrest et al. .......................... 395/750
`5,568,409 10/1996 Neoh ....................................... 364/702
`5,777,604 7/1998 Okajima et al. ........................ 345/173
`5,790,875 8/1998 Andersin et al. ....................... 713/321
`Primary Examiner Xuan M. Thai
`57
`ABSTRACT
`57
`A method for managing power consumption of a digitizing
`panel includes the steps of: (a) applying a biasing Voltage to
`the digitizing panel for a first period of time and ceasing to
`applv the biasing Voltage to the digitizing panel for a Second
`pply
`9.
`9.
`9.
`gp
`period of time; (b) determining whether a user has touched
`the digitizing panel during the first period of time; and (c) if
`the user has touched the digitizing panel during the first
`period of time, then applying a biasing Voltage to the
`digitizing panel for a third period of time that is longer in
`duration than the first period of time and ceasing to apply the
`biasing Voltage to the digitizing panel for a fourth period of
`time. An apparatus for implementing the method is also
`disclosed.
`
`25 Claims, 5 Drawing Sheets
`
`23
`
`26
`
`/
`
`/
`
`Eesa
`a
`NZ
`
`- 10
`
`
`
`
`
`
`
`16
`
`T.
`
`CONTROLLER
`
`CP
`
`MEMORY
`
`22
`
`25
`
`Petitioner STMICROELECTRONICS, INC.,
`Ex. 1013, IPR2021-01161 Page 1 of 12
`
`

`

`U.S. Patent
`
`May 2, 2000
`
`Sheet 1 of 5
`
`6,058,485
`
`23
`
`M N
`
`N
`
`Ele SA
`
`26
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`
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`
`
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`CONTROLLER
`
`19
`
`CPU
`
`MEMORY
`
`22
`
`25
`
`FIG.1
`
`2N o
`
`23a
`
`FIG.2
`
`23b
`
`U 23C
`
`Petitioner STMICROELECTRONICS, INC.,
`Ex. 1013, IPR2021-01161 Page 2 of 12
`
`

`

`U.S. Patent
`
`May 2, 2000
`
`Sheet 2 of 5
`
`6,058,485
`
`4. 14 N.
`
`27
`
`OX
`YYYYYYYYYYYYYYYYYYYYYYAYAAYAes
`arr VVA-VVV-Vry VVV-VVVV-VAV rap
`
`24
`
`
`
`
`
`
`
`
`
`
`
`37
`
`BASING
`CIRCUIT
`
`34a
`
`
`
`CHANNEL
`PRE-PROCESSOR
`
`
`
`COORDINATE
`GENERATOR
`
`34b)
`
`
`
`
`
`
`
`
`
`CHANNEL
`PRE-PROCESSOR
`
`
`
`
`
`CHANNEL
`PRE-PROCESSOR
`
`34d
`
`
`
`CHANNEL
`PRE-PROCESSOR
`
`
`
`
`
`DETECTION
`CIRCUIT
`
`FIG.4
`
`Petitioner STMICROELECTRONICS, INC.,
`Ex. 1013, IPR2021-01161 Page 3 of 12
`
`

`

`U.S. Patent
`U.S. Patent
`
`May2, 2000
`May 2, 2000
`
`Sheet 3 of 5
`Sheet 3 of 5
`
`6,058,485
`6,058,485
`
`
`
`
`
`FIG._5
`
`Petitioner STMICROELECTRONICS, INC.,
`Ex. 1013, IPR2021-01161 Page 4 of 12
`
`Petitioner STMICROELECTRONICS, INC.,
`Ex. 1013, IPR2021-01161 Page 4 of 12
`
`

`

`U.S. Patent
`
`May 2, 2000
`
`Sheet 4 of 5
`
`6,058,485
`
`74
`
`
`
`PEN
`POWER
`MANAGE-
`MENT
`
`
`
`- 70
`
`
`
`TOUCH
`POWER
`MANAGE
`
`Petitioner STMICROELECTRONICS, INC.,
`Ex. 1013, IPR2021-01161 Page 5 of 12
`
`

`

`U.S. Patent
`
`May 2, 2000
`
`Sheet 5 of 5
`
`6,058,485
`
`ITOUCH
`
`IPEN
`
`
`
`
`
`TIME
`FIG.7
`
`-90
`
`TTOUCH -
`TOUCH - - - - - - - - - -
`
`>
`
`- TPEN —
`
`IPEN
`
`TIME
`FIG.8
`
`Petitioner STMICROELECTRONICS, INC.,
`Ex. 1013, IPR2021-01161 Page 6 of 12
`
`

`

`1
`METHOD AND APPARATUS FOR
`MANAGING POWER CONSUMPTION OF A
`DIGITIZING PANEL
`
`6,058,485
`
`2
`energy Stored in Such batteries varies almost directly in
`proportion to their weight. Carrying heavy batteries of
`course, detracts from the portability of these machines.
`These power consumption issues are of particular concern
`to digitizing panels Since digitizing panels are a viable input
`alternative for the mouse and keyboard of portable comput
`ers. What is needed therefore is a method and an apparatus
`for managing power consumption of a digitizing panel.
`SUMMARY OF THE INVENTION
`In accordance with one embodiment of the present
`invention, there is provided a method for managing power
`consumption of a digitizing panel. The method includes the
`Steps of: (a) applying a biasing Voltage to the digitizing panel
`for a first period of time and ceasing to apply the biasing
`Voltage to the digitizing panel for a Second period of time;
`(b) determining whether a user has touched the digitizing
`panel during the first period of time; and (c) if the user has
`touched the digitizing panel during the first period of time,
`then applying a biasing Voltage to the digitizing panel for a
`third period of time that is longer in duration than the first
`period of time and ceasing to apply the biasing Voltage to the
`digitizing panel for a fourth period of time.
`Pursuant to another embodiment of the present invention,
`there is provided a controller for a digitizing panel. The
`controller includes a number of current measurement cir
`cuits and a biasing circuit. The number of current measure
`ment circuits are coupled to a number of points of the
`digitizing panel. The number of current measurement cir
`cuits generate a number of current values indicative of
`currents flowing through each of the number of points of the
`digitizing panel. The biasing circuit is coupled to the digi
`tizing panel. The biasing circuit, until a user touches the
`digitizing panel, periodically apply a biasing Voltage to the
`digitizing panel for a first period of time and cease to apply
`the biasing Voltage to the digitizing panel for a Second period
`of time. Then, the biasing circuit, until the user ceases to
`touch the digitizing panel, periodically apply the biasing
`Voltage to the digitizing panel for a third period of time and
`cease to apply the biasing Voltage to the digitizing panel for
`a fourth period of time, wherein the first period of time is
`shorter than the third period of time.
`It is an object of the present invention to provide a new
`and useful method for managing power consumption of a
`digitizing panel.
`It is another object of the present invention to provide a
`new and useful apparatus for managing power consumption
`of a digitizing panel.
`It is yet another object of the present invention to provide
`an improved method and apparatus of power management
`for a digitizing panel having a touch mode.
`It is yet a further object of the present invention to provide
`an improved method and apparatus that reduce power con
`Sumption of a digitizing panel operating in a pen-and-touch
`mode.
`The above and other objects, features, and advantages of
`the present invention will become apparent from the fol
`lowing description and the attached drawings.
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a simplified block diagram of an exemplary
`computer which incorporates the features of the present
`invention therein;
`FIG. 2 is a perspective view of the pen shown in FIG. 1;
`FIG. 3 is a perspective View of a digitizing panel and
`associated display device taken along the line 3-3 in FIG.
`1;
`
`1O
`
`25
`
`35
`
`40
`
`15
`
`BACKGROUND OF THE INVENTION
`The present invention relates generally to digitizing
`panels, and more particularly to a method and apparatus for
`managing power consumption of a digitizing panel.
`Digitizing panels having a resistive layer covered with a
`non-conductive plate Such as glass, are known in the art. The
`known digitizing panels may operate in one of two modes,
`namely a touch mode or a pen mode. When operating in the
`touch mode, a computer is conventionally configured So as
`to capacitively bias the resistive layer by applying to a shield
`layer of the digitizing panel an AC signal. An object Such as
`a user's finger that approaches and contacts the non
`conductive plate acts as a load that is capacitively coupled
`to the resistive layer. The capacitively coupled load causes
`electric current to flow through the corners of the resistive
`layer. The computer may determine a Cartesian coordinate
`(X, Y) position of an object relative to the digitizing panel,
`based on the current flow in each of the corners of the
`resistive layer in a manner known to one of ordinary skill in
`the art. More particularly, the position of the pen relative to
`the digitizing panel may be determined based upon a ratio of
`the corner currents or signals that flow through the corners
`of the resistive layer due to the object being capacitively
`coupled to the resistive layer.
`When operating in the pen mode, the computer is con
`ventionally configured So as to be receptive to a signal
`transmitted from a hand-held Stylus or pen. In particular, a
`pen typically includes a battery portion which Supplies
`power to an oscillator portion for Stimulating a coil associ
`ated with a transmitter portion to transmit an AC Signal from
`a tip of the pen. The AC Signal may be transmitted from the
`pen tip when the tip contacts an object or Surface Such as the
`non-conductive plate associated with the digitizing panel.
`The transmitted AC signal is typically capacitively
`coupled to the resistive layer associated with the digitizing
`panel. The capacitively coupled AC signal induces an elec
`tric current flow through each of the corners of the resistive
`layer. AS in the touch mode, the position of the pen relative
`to the digitizing panel may then be determined based upon
`a ratio of the corner currents or signals that flow through the
`corners of the resistive layer due to the AC signal transmitted
`from the pen.
`Therefore, these digitizing panels must bias the resistive
`layer with an AC signal in order to detect a touch but need
`not bias the resistive layer with an AC Signal in order to
`detect a pen because the pen transmits an AC Signal to the
`resistive layer. Furthermore, more hardware is required to
`detect a touch than to detect a pen due to the Signal
`characteristics of the currents that flow through the corners
`of the resistive layer in response to pen contact and the
`Signal characteristics of the currents that flow through the
`corners of the resistive layer in response to a touch. This
`biasing of the resistive layer and the powering of the
`additional hardware to detect a touch consumes power.
`However, reducing power consumption in portable com
`60
`puterS has gained a great deal of attention in the technical
`community as a result of a Set of conflicting user require
`ments and technological constraints. On the one hand, users
`would like to operate these portable devices for extended
`periods of time without access to an AC wall outlet. This
`means that Such devices must carry their own power Sources,
`i.e., batteries of various types. On the other hand, the total
`
`45
`
`50
`
`55
`
`65
`
`Petitioner STMICROELECTRONICS, INC.,
`Ex. 1013, IPR2021-01161 Page 7 of 12
`
`

`

`3
`FIG. 4 is a block diagram of the controller shown in FIG.
`1;
`FIG. 5 is a State diagram depicting a method for control
`ling a digitizing panel which does not utilize certain power
`management features of the present invention;
`FIG. 6 is a State diagram depicting a method for control
`ling a digitizing panel that utilizes power management
`features of the present invention;
`FIG. 7 is a current versus time graph during the Search
`states of FIG. 5 and FIG. 6; and
`FIG. 8 is a current versus time graph during the power
`management States of FIG. 6.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`While the invention is susceptible to various modifica
`tions and alternative forms, a specific embodiment thereof
`has been shown by way of example in the drawings and will
`herein be described in detail. It should be understood,
`however, that there is no intent to limit the invention to the
`particular form disclosed, but on the contrary, the intention
`is to cover all modifications, equivalents, and alternatives
`falling within the Spirit and Scope of the invention as defined
`by the appended claims.
`Referring now to FIG. 1, there is shown a functional block
`diagram of a computer 10 Such as a notebook or mobile
`computer which incorporates the features of the present
`invention therein. The computer 10 includes an electrostatic
`digitizing tablet or panel 14, controller 16, conventional
`central processing unit (CPU) 18, random access memory
`(RAM) 19, and display device 26 such as a liquid crystal
`display (LCD). The digitizing panel 14 is operatively
`coupled to the controller 16 through a number of corner
`wires 20a–20d and a biasing wire 35, and the CPU 18 is
`operatively coupled to the display device 26 through a
`display interface 21. Furthermore, the controller 16 is opera
`tively coupled to the CPU 18 through a serial data line 22
`Such as a Serial port, and the memory 19 is operatively
`coupled to the CPU 18 through a system bus 25.
`A conventional hand-held Stylus or pen 23 is used to input
`data into the computer 10 in a known manner, when the
`computer 10 is operating in a pen mode as described further
`below. Referring to FIG. 2, the pen 23 may be a cordless
`type pen having a battery portion 23a, oscillator portion 23b
`and transmitter portion 23c. The battery portion 23a Supplies
`power to the oscillator portion 23b which then stimulates a
`coil (not shown) associated with the transmitter portion 23c,
`to transmit an AC signal 23d (FIG. 1). In the embodiment
`being described, the Signal 23d may have a carrier frequency
`of approximately 125 kHz.
`The electroStatic digitizing panel 14 may include Several
`layers of known material as shown in FIG. 3. In the
`embodiment being described, a glass layer 24 protects the
`display device 26 which is disposed below the glass layer
`24. An upper Surface 27 of the glass layer 24 defines a
`Writing/touching Surface for an object Such as the pen 23 or
`a user's finger (not shown). A lower Surface of the glass layer
`24 has a resistive layer 28 of an active Sensor material
`applied thereto. In the embodiment being described, the
`active Sensor material may be a thin coating of transparent
`indium-tin-oxide (ITO) which is typically used in electro
`Static digitizing panel applications.
`Each corner wire 20a-20d is electrically connected to a
`respective corner of the resistive layer 28 for carrying
`current flow generated as a result of an object contacting the
`
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`6,058,485
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`4
`glass layer 24 as described further below. A polyester Spall
`shield 30 is attached to the underside of the resistive layer 28
`to prevent the glass Surface 24 from Shattering if ever
`broken. A lower surface of the spall shield 30 has an active
`ITO shield layer 31 applied thereto. The shield layer 31
`forms an electrical Shield reducing noise coupling from the
`LCD screen 26 to the resistive layer 28. Furthermore, the
`shield layer 31 provides the control with a mechanism for
`capacitively biasing the resistive layer 28 with a biasing
`Voltage. An air gap 32 Separates the lower Surface of the
`spall shield 30 from an upper surface of the LCD screen 26.
`The controller 16 may operate in one of two operational
`modes, namely a touch mode and a pen mode, or in one of
`two power management modes, namely a touch power
`management mode and a pen power management mode
`which are described later. In the touch mode of operation,
`the controller 16 capacitively biases the resistive layer 28 by
`applying to the Shield layer 31 an AC signal. In particular,
`the controller 16 applies a 125 kHz biasing voltage to the
`resistive layer 28 via biasing wire 35 and the shield layer 31.
`AS long as an object is not approaching the digitizing panel
`14, the controller 16 is in a quiescent State and a finite
`amount of AC offset current may flow through the corner
`wires 20a-20d due to loading effects caused by stray or
`parasitic capacitance between the resistive layer 28 and any
`metal components of the computer 10 proximate the resis
`tive layer 28.
`When an object does approach the digitizing panel 14, the
`object increasingly acts as a capacitive load that is coupled
`to the resistive layer 28. An object that is capacitively
`coupled to the resistive layer 28 acts as a load on the resistive
`layer 28 which results in current flow through each of the
`corners of the resistive layer 28, and through the corner
`wires 20a-20d. The controller 16 may determine a Cartesian
`coordinate (X, Y) position of an object Such as a user's
`finger relative to the digitizing panel 14, based on the current
`flow in each of the corner wires 20a-20al in a manner known
`to one of ordinary skill in the art.
`In the pen mode of operation, the controller 16 grounds
`the shield layer 31. Furthermore, while in pen mode of
`operation, the controller 16 is receptive to the Signal trans
`mitted from the pen 23. In particular, a current flow is
`generated in each of the corner wires 20a-20d when the
`Signal transmitted from the pen 23 is brought within close
`proximity to the digitizing panel 14. The controller 16 may
`determine a Cartesian coordinate (X, Y) position of the pen
`23 relative to the digitizing panel 14, based on the current
`flow in each of the corner wires 20a-20a.
`The magnitude of current flow through each of the corners
`of the resistive layer 28 (and in each of the corner wires
`20a-20d) due to an object (pen or finger) which is capaci
`tively coupled to the resistive layer 28, is proportional to the
`conductivity of the resistive layer 28 between each corner of
`the resistive layer 28 and the object at a particular position
`on the glass layer 24 as shown in FIG.1. More particularly,
`the closer the object is to a particular corner of the resistive
`layer 28, the greater the conductivity of the resistive layer 28
`and the greater the current flow through that corner.
`Likewise, the farther the object is from a particular corner of
`the resistive layer 28, the lower the conductivity of the
`resistive layer 28, and the lower the current flow through that
`corner. This current relationship to the corners of the resis
`tive layer 28 is depicted in FIG. 1 by the relative thickness
`of lines extending between the object position and each of
`the corners of the resistive layer 28.
`Referring now to FIG. 4, there is shown a simplified
`functional block diagram of the controller 16. In particular,
`
`Petitioner STMICROELECTRONICS, INC.,
`Ex. 1013, IPR2021-01161 Page 8 of 12
`
`

`

`S
`the controller 16 includes a number of current measurement
`circuits or channel pre-processors 34a–34d, a coordinate
`generator 36, a biasing circuit 37, and a detection circuit 38.
`Each channel pre-processors 34a–34d conventionally
`generates a current value that is indicative of the magnitude
`of current flowing through its respective corner wire
`20a-20d. In the preferred embodiment, the channel pre
`processors 34a–34d generate the current values by convert
`ing the current flowing through the respective corner wires
`20a–20d into analog Voltage Signals that are indicative of the
`magnitude of current flowing through the respective corner
`wires 20a-20d. In addition, the channel pre-processors
`34a–34d typically filter, rectify and convert the analog
`Voltage Signals into digital values in a known manner prior
`to placing the current values on lines 44a–44d. In the
`embodiment being described, the channel pre-processors
`34a–34d convert the magnitude of the currents flowing
`through the corner wires 20a-20d into current values at a
`Sampling rate of approximately 100 Samples/Second.
`The biasing circuit 37 has at least two operational States,
`a normal State and a sleep State. During the normal State, the
`biasing circuit 37 conventionally Supplies a biasing Voltage
`to the shield layer 31 via biasing wire 35 for stimulating the
`resistive layer 28 so that a user's touch can be detected. In
`the preferred embodiment, the biasing circuit 37 conven
`tionally Supplies a 125 kHz biasing Voltage to the shield
`layer 31. Furthermore, during the Sleep State, the biasing
`circuit 37 ceases to supply the shield layer 31 with the
`biasing Voltage. In the preferred embodiment, the biasing
`circuit 37 consumes less power when in the Sleep State than
`when in the normal state. Furthermore, in the preferred
`embodiment, the biasing circuit 37 is designed to enter the
`normal State during touch and touch power management
`modes of operation and to enter the Sleep State during pen
`and pen power management modes of operation.
`The coordinate generator 36 receives the current values
`on lines 44a–44d and determines from the current values
`Cartesian (X, Y) coordinate pairs that depict the relation of
`the object relative to the digitizing panel 14. In particular, the
`position of an object relative to the digitizing panel 14 may
`be determined based upon a ratio of the Sum of certain
`current values to the Sum of the current values. This deter
`mination of coordinate pairs may be represented by equa
`tions (1a) and (1b):
`
`X = - (1a)
`CO+ C1 + C2+ C3
`
`Y = - (1b)
`CO + C1 + C2+ C3
`
`where C0, C1, C2, and C3 are the current values that channel
`pre-processors 34a–34d have placed upon lines 44a–44d
`respectively. The resulting coordinate pairs are Sent from the
`coordinate generator 36 and received by the CPU 18 via line
`22. The CPU 18 may use the reported coordinate pairs on
`line 22 for determining the position of the object to the
`digitizing panel and for performing a task Such as causing
`digital ink to be displayed on display device 26.
`The coordinate generator 36 furthermore has two opera
`tional States, a normal State and a Sleep State. During the
`normal State, the coordinate generator 36 generates coordi
`nate pairs from the current values. Furthermore, the coor
`dinate generator 36, when in the normal State, may be caused
`to enter the sleep state. When the coordinate generator 36 is
`in the Sleep State, the coordinate generator consumes leSS
`power than when in the normal State but does not generate
`
`6,058,485
`
`6
`coordinate pairs. While in the Sleep State, the coordinate
`generator 36 is responsive to a wake-up signal which when
`received causes the coordinate generator 36 to enter the
`normal State.
`The detection circuit 38 receives as inputs the current
`values from lines 44a–44d or alternatively the currents from
`the corner wires 20a-20al. The detection circuit 38 deter
`mines from these inputs whether a pen 23 is in close
`proximity to the digitizing panel 14. The detection circuit 38
`makes this determination by Summing the inputs and com
`paring the Sum to a threshold value. If the Sum is greater than
`the threshold value, the detection circuit 38 generates a
`wake-up signal. The threshold value is a value greater than
`the Sum of the inputs resulting from a user touching the
`digitizing panel 14 during pen mode and less than the Sum
`of the inputs resulting from a pen contacting the digitizing
`panel during pen mode. In this manner, the detection circuit
`38 provides the controller 16 with a mechanism for deter
`mining when a pen is in close proximity to the digitizing
`panel 14.
`In the preferred embodiment, the controller 16 operates
`the digitizing panel 14 in a pseudo pen-and-touch mode. At
`any one point in time, the controller 16 may be in pen mode,
`touch mode, pen power management mode, or touch power
`management mode. However, by quickly Switching between
`the various modes, the digitizing panel 14 appears from a
`user's viewpoint to concurrently Support input from either a
`pen 23 or a users touch.
`Referring now to FIG. 5, there is shown a state diagram
`50 that depicts ne method for controlling the digitizing panel
`14 when certain power management features of the present
`invention are not utilized. The state diagram 50 includes a
`pen Search State 52, a touch search State 54, a pen sample
`state 56, a pen hold state 58, a touch hold state 60, and a
`touch delay state 62.
`In the pen search state 52, if the controller 16 is not
`already in pen mode then the controller 16 is placed into the
`pen mode of operation. When the controller 16 enters the
`pen Search State 52, a timer is Set. If the timer expires before
`pen proximity is detected, then the controller 16 transitions
`to the touch search state 54. However, if pen proximity is
`detected before the timer expires, then the pen is determined
`to be the primary input device and the controller 16 transi
`tions into the pen hold state 58.
`In the touch search state 54, if the controller 16 is not
`already in touch mode, the controller 16 is placed into the
`touch mode of operation. When the controller 16 enters the
`touch Search State 54, a timer is Set. If the timer expires prior
`to a touch detection, then the controller 16 transitions into
`the penSearch State. However, if a touch is detected, then the
`controller 16 transitions into the pen sample state 56.
`In the pen sample state 56, if the controller 16 is not
`already in pen mode, the controller 16 is placed into the pen
`mode of operation. When the controller 16 enters the pen
`sample state 56, a timer is set. If the timer expires before a
`pen proximity detection, then the controller 16 transitions
`into the touch hold state 60. However, if a pen proximity is
`detected, then the controller 16 transitions into the pen hold
`State 58.
`In the touch hold state 60, if the controller 16 is not
`already in the touch mode of operation, then the controller
`16 is placed into the touch mode of operation. When the
`controller 16 enters the touch mode of operation, a timer is
`set. When the timer expires, the controller 16 transitions into
`the pen Sample State 56. If a touch is no longer detected
`before the timer expires, then the controller 16 transitions
`into the touch delay state 62.
`
`15
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`25
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`35
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`40
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`45
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`50
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`55
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`60
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`65
`
`Petitioner STMICROELECTRONICS, INC.,
`Ex. 1013, IPR2021-01161 Page 9 of 12
`
`

`

`7
`It should be appreciated that if a user is touching the
`digitizing panel, the controller 16 will continuously Switch
`between the touch hold state 60 and the pen sample state 56.
`This continuous Switching in essence causes the controller
`16 to Sample for pen proximity on a periodic basis even
`though a user is touching the digitizing panel 14. This
`Sampling for pen proximity corrects for the Situation in
`which the user is touching the digitizing panel 14 when
`using a pen 23. For example, the user may be resting their
`hand upon the digitizing panel 14 while writing with the pen
`23.
`In the pen hold state 58, the controller 16 remains in the
`pen mode of operation. AS long as the pen remains in
`proximity with the digitizing panel 14, the controller 16
`remains in the pen hold state 58. A timer is set whenever the
`pen leaves proximity of the digitizing panel 14. If the timer
`expires before pen proximity is re-established, then the
`controller 16 transitions into the touch search state 54.
`In the touch delay state 62, the controller 16 remains in the
`touch mode of operation. Furthermore, upon entering the
`touch delay State 62, a timer is Set. If the timer expires before
`a touch detection, then the controller 16 transitions into the
`touch search state 54. If, however, a touch is detected before
`the timer expires, then the controller transitions back to the
`touch hold state.
`With reference now to FIG. 6, a state diagram 70 depicts
`one method for controlling the digitizing panel 14 when
`power management features of the present invention are
`utilized. The state diagram 70 has several states that are
`substantially the same as the states of state diagram 50 of
`FIG. 5 and as a result will not be discussed further. The state
`diagram 70 introduces two new States into the State diagram
`50, the touch power management State 72 and the pen power
`management State 74. The State diagram 70 also replaces pen
`search state 52 with pen search state 71 which is a slightly
`altered version of pen Search State 52.
`The pen search state 71 is nearly identical to the pen
`search state 52 of FIG. 5. The pen search state 71, however,
`includes a second timer that is set when the controller 16 first
`enters the pen Search State 71 and is not reset until the
`controller reenters the pen search state 71 after have entered
`the pen Sample State 56. In essence this Second timer tracks
`how long the controller 16 remains switching between the
`pen search state 71 and the touch search state 54. If this
`second timer expires while the controller 16 is in the pen
`search state 71, then the controller 16 transitions into the
`power management State 72.
`Upon entering into the touch power management State 72,
`the controller 16 is placed into a touch power management
`mode and a timer is Set. If the timer expires prior to a touch
`detection, then the controller 16 transitions into the pen
`power management State 74. However, if a touch is detected,
`then the controller 16 transitions into the touch hold state 60.
`Upon entering into the pen power management State 74,
`the controller 16 is placed into a pen power management
`mode. The goal during the pen power management mode is
`to place all components of the controller 16 that are not
`required to detect pen proximity in a low power or Sleep
`mode. For example, in the preferred embodiment, the detec
`tion circuit 38 is powered but the coordinate generator 36
`and the biasing circuit 37 are in a low power or Sleep mode.
`Furthermore, if the detection circuit 38 is coupled to the
`corner wires 20a-20d, then the channel pre-processors
`34a–34d may also be placed in a low power or sleep mode.
`Also upon entering into the pen power management State
`74, the controller 16 sets a timer. If the timer expires prior
`to a pen proximity detection, then the controller 16 transi
`
`15
`
`25
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`6,058,485
`
`8
`tions into the touch power management State 72 and awak
`ens the channel pre-processors 34a–34d, the coordinate
`generator 36, and the biasing circuit 37. However, if pen
`proximity is detected, then the controller 16 transitions into
`the pen hold state 58 and awakens the channel pre
`processors 34a–34d and the coordinate generator 36.
`It should be appreciated that the pen search state 71 and
`the pen management State 74 could be combined into one
`State that utilizes the pen power management mode. In
`essence, the controller 16 would enter pen power manage
`ment mode whenever the controller 16 transitioned into pen
`search state 71.
`The touch mode and the touch power management modes
`are nearly identical. The major difference is that the timer Set
`in the touch power management State 72 is shorter in
`duration than the timer set in the touch hold state 60. This
`difference in timer duration and the effects this difference
`has on power consumption may be better understood with
`reference to FIG. 7 and FIG. 8. Furthermore, the timers of
`the touch power management State 72 and the touch hold
`state 60 in the preferred embodiment are programmable. In
`other words, the duration of the timers may be adjusted by
`a user, the computer 10, or other components of controller 16
`even during operation. For example, the user may wish to
`tweak the performance of the system, or the controller 16
`may contain fuzzy logic which may increase the time spent
`in the touch power management State 72 when the fuZZy
`logic “believes” a touch has occurred but is not quite “sure.”
`In FIG. 7 there is shown a current versus time graph 80
`of when the controller 16 is switching between the pen
`search state 52 and the touch search state 54 (FIG. 5) or
`when the controller 16 is switching between the pen search
`state 71 and the touch search state 54 (FIG. 6). The T touch
`interval or period is the length of time the controller 16
`remains in the touch search state 54 and is set by the timer
`of the touch search state 54. The T interval or period is the
`length of time the controller 16 remains in the pen Search
`state 52 or the pen search state 71 and is set by a timer of the
`respective State. The It, current is the current consumed
`during the touch search state 54. Likewise, the I
`cu