Source: https://patents.google.com/patent/KR101060210B1/en
Timestamp: 2020-01-22 06:15:34
Document Index: 54652178

Matched Legal Cases: ['Application No. 10', 'Application No. 10', 'Application No. 60', 'Application No. 60', 'Application No. 10', 'Application No. 10', 'Application No. 10', 'Application No. 60', 'Application No. 10', 'Application No. 60', 'Application No. 10']

KR101060210B1 - Contact detection of digitizer - Google Patents
Contact detection of digitizer Download PDF
KR101060210B1
KR101060210B1 KR1020057014719A KR20057014719A KR101060210B1 KR 101060210 B1 KR101060210 B1 KR 101060210B1 KR 1020057014719 A KR1020057014719 A KR 1020057014719A KR 20057014719 A KR20057014719 A KR 20057014719A KR 101060210 B1 KR101060210 B1 KR 101060210B1
KR1020057014719A
KR20050101204A (en
메어 모라그
하임 퍼스키
엔 트리그 리미티드.
2003-02-10 Priority to US60/446,808 priority
2003-09-05 Priority to US60/501,484 priority
2004-01-15 Application filed by 엔 트리그 리미티드. filed Critical 엔 트리그 리미티드.
2005-10-20 Publication of KR20050101204A publication Critical patent/KR20050101204A/en
2011-08-29 Application granted granted Critical
2011-08-29 Publication of KR101060210B1 publication Critical patent/KR101060210B1/en
The detector of the present invention, which detects contact by a finger or similar body part to the sensor, comprises at least one sensing conductor, typically a grid of conductors extending into the sensor, an oscillation source that oscillates electrical energy at a predetermined frequency. And a detection circuit for detecting a capacitive effect on the sensing conductor when the oscillating electrical energy is applied. The detector has the advantage that the same sensing conductor can be used for contact sensing and detection of the electromagnetic stylus.
Digitizer, Stylus, Finger Contact, PDP
TOUCH DETECTION FOR A DIGITIZER}
The present invention relates to a combined touch and stylus digitizer and is not particularly applicable only to detection by finger contact.
As computers become popular, extensive research and development is underway in the field of digitizers and touch screens. While there are many inventions describing touch panels, only a few describe digitizers that can detect EM stylus and finger contacts using the same sensing device. "Physical Object Location Apparatus and Method and a Platform using the same" of U.S. Patent Application Serial No. 09 / 629,334, issued July 7, 2000, to N-trig Ltd, and August 28, 2003, also assigned to N-trig Ltd. "Transparent Digitizer" in US patent application Ser. No. 09 / 628,334 describes a positioning device capable of detecting a plurality of physical objects, preferably a stylus, located on a flat display.
“Dual Function Input Device And Method” of US Patent Application No. 10 / 270,373, filed Oct. 15, 2002, assigned to N-trig Ltd., uses the same transparent sensor to detect an electromagnetic object and finger contact. It describes a possible system. In this technique, finger contact detection is performed by a matrix-shaped resistive stripe incorporated into the EM detection pattern. A special separation layer can be arranged between the conductor layers to simultaneously contact the stripe and prevent contact between EM lines. Driving and reading contact signals from sensors requires additional electronics, a major drawback of this approach is that it complicates both the sensors and the electronics.
U.S. Patent No. 3,944,740 uses an input pad mounted on top of a plasma display panel, which is a matrix-shaped conductive row and column, where the stylus with the conductive tip is positioned with the stylus position. It is arranged to short-circuit the row and column electrodes at the point of contact of the stylus by currents conducted through the row and column electrodes that are shown. U.S. Patent No. 4,639,720 uses a similar idea of using conductive pixels instead of matrix-shaped rows and columns.
The main disadvantage of the above two patents is the inability to detect low resolution stylus and especially electromagnetic type stylus. Since the stylus is detected only when the two auxiliary lines / pixels are shortcut, the stylus cannot be detected when the stylus is located between the lines / pixels. Thus the resolution of stylus detection is limited to the accessibility of the line / pixel. As disclosed in these patents, stylus detection is essentially different from that described in the preferred embodiment of the present invention. U. S. Patent No. 6,239, 389 describes a method of performing finger detection by measuring a first set of voltage values from each conductive line and calculating a weighted average of the values with respect to samples generated without the assistance of a finger. The sensor consists of a series of plates arranged in rows and columns and connected by conductive lines. The main disadvantage of this method is that it requires an computing device to calculate the weighted average of the sampled values, so that the EM stylus cannot be detected and the sensor is not transparent.
U. S. Patent 4,550, 221 discloses a sensor arrangement having a series of conductive plates / pixels connected by conductive wires. Finger touch changes the capacitance of the pixel with respect to the surrounding ground. This change is detected and converted to indicate the position of the finger. According to the contents of this patent, the EM stylus cannot be detected with the detection of the finger. The plate / pixel of the sensor is not transparent and therefore cannot be mounted on the display screen.
U. S. Patent No. 4,293, 734 utilizes two current sources to drive a predetermined current through each end of the antenna. The position of the finger is calculated using Kirchoff's law for the leakage current flowing through the finger to ground. A disadvantage of the detection system disclosed herein is the inability to detect EM stylus. Instead, the system requires current flow at both ends of the conductive surface, which has been found to consume a lot of power. Detection is also an analog value and involves a relatively complex circuit.
US Pat. No. 6,452,514 uses two or more electrodes to generate an electric field transmitted through an adjacent dielectric, which may be interrupted by access to a conductive object. A charge transfer measurement circuit is connected to one of the electrodes for determining the presence of an object. The patent discloses connecting each electrode to each charge transfer measuring device. The disadvantages of this patent invention are the inability to detect EM stylus, low update rate and limited resolution.
US Pat. No. 6,583,676 describes a method for detecting capacitance generated by a finger based on the application of frequency change. Adjustment circuits and methods for access / contact detectors enable automatic adjustment of access / contact detector components, chassis effects and ambient conditions, eliminating the need for initial factory adjustments and periodic manual adjustments. The adjustment circuit switches the capacitance to the capacitance of the oscillator to change the input frequency of the free Schmitt trigger drive oscillator. The capacitance sensor forms part of the input capacitance. The frequency shift associated with the difference in input capacitance generated when an object such as a finger contacts a capacitive sensor and when the capacitive sensor is dropped from contact with the object is simulated as a change in frequency. The biggest disadvantage of this invention is that additional hardware is needed and the EM stylus cannot be detected.
Other methods of finger contact detection can be found in US Pat. Nos. 6,587,093, 6,633,280 and 6,278,443, which describe methods of finger contact detection that are substantially different from those described herein. Neither has an EM stylus and the ability to detect finger touch.
Therefore, the need for a digitizer system that circumvents the above limitations is widely recognized, and it is highly desirable to have such a system.
According to one aspect of the invention, there is provided a detector for providing a first type of position detection in addition to a second type of position detection.
In connection with the above arrangement, a detection circuit is provided which detects a signal arising from the first kind of position detection and a signal arising from the second kind of position detection at the same sensing conductor and from there the position of the sensor.
Preferably, the first type of position detection includes resonance-based object detection of an object capable of generating a resonant electromagnetic field.
Preferably the first kind of position detection comprises capacitive-based contact detection.
Preferably, the first kind of position detection comprises resonance-based object detection of an object capable of generating a resonant electromagnetic field, and the second kind of position detection comprises capacitive-based contact detection.
Preferably, the detection circuit can simultaneously detect the first kind of interaction and the second kind of interaction.
Preferably the detection circuitry can independently detect the first kind of interaction and the second kind of interaction.
Preferably the sensor comprises an oscillator positioned over the detection area and providing an excitation signal that can excite a resonant circuit of an electromagnetic stylus-type object, the oscillator providing an oscillation signal, said patterned arrangement Has a conductive element extending over the detection area, the detection circuit being adapted to detect the capacitive effect of a conductive object such as finger contact and resonance from an electromagnetic stylus-type object in at least one conductive element.
Preferably the oscillator is connected to provide an oscillation signal to the excitation circuit and also to provide an excitation signal for capacitive based contact detection.
Preferably the sensor is substantially transparent and suitable for placement on the display screen.
Preferably the detection area is the surface of the display screen and the sensor comprising at least one conductor element is substantially transparent.
The detector may comprise a plurality of conductive elements, and the detection circuit may have a differential detector arrangement associated with the sensing conductor for detecting the difference between the outputs of the sensing conductors.
Preferably the sensing circuit is configured to sense the signal in at least one sensing conductive element induced by the contact of the conductive object receiving the oscillation signal.
Preferably at least a second conductive element located inside the sensor and having a junction with the at least a conductive element is provided, the oscillator is applied to one conductive element and the junction has its own alternating current short circuit by contact by the capacitive body part. The detector is configured to detect the resulting oscillation signal at the second conductive element and to estimate the contact therefrom.
Preferably the detection circuit is adapted to detect a signal at least in the second conductive element for analysis as a plurality of contact objects.
Preferably a number of resonance-based objects can be detected by interpreting the properties of the detected signal.
Preferably a plurality of conductive objects can be detected by interpreting the properties of the detected signal.
The oscillator is preferably connected to oscillate at least one detector, part of the detector and at least one conductive element with respect to a reference voltage level so that capacitive current flows between the conductive contact object and the at least one conductor.
Preferably the sensor is configured to place the transparent medium between itself and the display screen below it.
Preferably the transparent medium comprises an air gap.
According to a second aspect of the present invention, there is provided a detector for detecting a contact by a conductive object making a capacitive contact with a transparent sensor positioned on a display screen, wherein the detector comprises:
An oscillation source for oscillating electrical energy at a predetermined frequency, and
And a detection circuit for detecting capacitive effects on at least one sensing conductor when oscillating electrical energy is applied.
Preferably the detection circuit has a differential detector arrangement associated with the sensing conductor for detecting the difference between the outputs of the conductors.
Preferably the electrical energy oscillation source is configured to deliver electrical energy to the conductive object, wherein the sensing conductor is configured to sense a signal of at least one sensing conductor element induced by the contact of the conductive object with received oscillation energy.
Preferably the detector is configured to interpret the properties of the detected signal in at least one conductor with respect to the plurality of contacting conductive objects.
Preferably at least a second conductor is installed inside the sensor and having a junction with the at least one conductor element, an electrical energy oscillation source is applied to one conductor and the junction is alternating shorted at itself by contact with a conductive object. And detect the oscillation signal at the second conductor as a capacitive effect to estimate the contact.
Preferably the detection circuit is configured to interpret the characteristics of the detected signal as a plurality of contacts of the corresponding conductor.
The detector may comprise a matrix comprising first sensors aligned in a first direction and second sensors aligned in a second direction and having a plurality of junctions between the first sensors and the second sensors. . In addition, tabulation of the leakage capacitance value for each junction may be provided, and the detector is configured to correct the reading at each conductor using the leakage capacitance value.
Preferably the electrical energy oscillation source is connected to oscillate the at least one detector, part of the detector and at least one conductor with respect to the reference voltage level so that a capacitive current flows between the conductive object and the at least one conductor.
Preferably the electrical energy oscillation source is connected to vibrate the first portion of the detector, the first portion being connected to a second portion that is not vibrated through the communication connection, the communication connection being connected to the first portion of the detector. It is not affected by the potential difference between the two parts.
Preferably the communication connection comprises at least one differential amplifier.
Preferably the sensor consists of a transparent medium between itself and the display screen.
Preferably the transparent medium comprises voids.
Preferably the sensor comprises a conductor grid disposed inside one layer thereof.
Preferably, the conductors are connected to the amplifier in pairs.
Preferably the amplifier is a differential amplifier each having a + input and a-input, one of the conductor pairs connected to the + input and the other connected to the-input.
The detector may have a compensation table that provides a compensation value at each conductor to compensate for static noise.
The detector may be configured to update the compensation table at system startup.
The detector may be configured to use obscure object detection as a trigger for refreshing the compensation table.
Preferably any combination of number, phase and position data of the detected signals is used to define ambiguity in object detection.
According to a third aspect of the invention, there is provided a method of sensing contact in a matrix-shaped sensing conductor located in a transparent sensor on an electronic display screen, the method comprising:
Providing an oscillation signal at a predetermined frequency, and
Measuring the conductor for the effect of dose to the conductor by contact of the conductor.
The method includes providing an oscillation signal to an external transmitter to energize the contact portion.
Preferably the matrix has a first conductor aligned in a first direction and a second conductor aligned in a second direction, the method comprising: a capacitance produced by a conductive object that provides and contacts an oscillation signal to the first conductor Sensing an oscillation signal at any one of the second conductors through which the oscillation signal has passed through the gender link.
The method may include providing an oscillation signal to at least the conductor such that the conductive contact draws current from each conductor.
The method may include using an oscillation signal to vibrate a detection mechanism with a conductor, the oscillating detection mechanism being simultaneously insulated from common ground.
The method includes using an oscillation signal to vibrate a first portion of the detection mechanism, the first portion having a conductor,
Insulating the first portion from the second portion, and
Using an insulated second portion to deliver a contact detection output to an external device.
According to a fourth aspect of the invention, there is provided a method of manufacturing a contact detector for an electronic display screen, which method comprises:
Providing an oscillating signal source;
Embedding a grid of transparent conductors in at least one transparent foil;
Disposing a transparent foil on the electronic display screen, and
Providing a detection circuit to detect a capacitive effect on the conductor.
The method includes using a excitation device around an electronic screen to excite the electromagnetic stylus such that the position of the stylus is detectable in the grid of transparent conductors.
According to a fifth aspect of the invention, there is provided a contact detection device, which comprises:
A sensor having at least one sensing conductor element,
An oscillator providing an oscillation signal,
A transmitter for transmitting an oscillation signal in the vicinity of a sensor in association with said oscillator, and
And a sensing circuit for sensing a signal in at least one sensing conductor element induced by the contact of a conductive object receiving the transmitted oscillation signal.
According to a sixth aspect of the invention, there is provided a contact detection device, which comprises:
A sensor comprising a grid arrangement comprising a first sensing conductor and a second sensing conductor, the junction having a junction therebetween,
An oscillator for providing an oscillation signal to the first sensing conductor, and
And a detection circuit for detecting the oscillation signal when an oscillation signal is transmitted to the second sensing conductor through the junction, wherein the transfer is a capacitive coupling induced by the contact of a conductive object contacting the sensor at each junction. Indicates.
According to a seventh aspect of the invention, there is provided a contact detection device, which comprises:
A sensor having at least one sensing conductive element,
An oscillator for providing an oscillation signal, the oscillation signal being provided to at least a portion of an apparatus having at least one sensing conductive element, and
And a detection circuit for detecting an AC ground of the at least one sensing conductive element by capacitive connection to a conductive object in contact with the sensor.
Unless defined otherwise, all technical and scientific terms used herein have the meaning commonly understood by one of ordinary skill in the art to which this invention belongs. The materials, methods, and examples illustrated herein are for illustrative purposes only and not intended to be limiting.
Implementation of the method and system of the present invention includes executing or completing any selected task or step manually, automatically, or a combination thereof. In addition, according to the practical implementation and apparatus of the preferred embodiment of the method and system of the present invention, some selection steps may be performed by software on the operating system of hardware or any firmware, or a combination thereof. For example, as hardware, the optional steps of the invention may be implemented as a chip or a circuit. As software, selected steps of the present invention may be embodied as a plurality of software instructions executed by a computer using a suitable operating system. In any case, selected steps of the methods and systems of the present invention may be described as being executed by a data processor, such as a computing platform for executing a plurality of instructions.
The invention is here only described by way of example in connection with the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A detailed description will now be made as an example in particular with reference to the drawings, which are intended to provide only what is described as exemplary purposes of the preferred embodiments of the invention and which are recognized as being most useful and understandable with respect to the principles and conceptual features of the invention. Is provided. In this regard, the configuration by the academic analysis of the present invention is not described in detail, but describes what is necessary for a basic understanding of the present invention, and how each embodiment of the present invention is practically realized is described by those skilled in the art from the description related to the drawings. Will be self-explanatory.
1A is a schematic block diagram illustrating a general embodiment of the present invention.
1B is a schematic diagram illustrating one embodiment of the present invention in which oscillation energy is delivered to a finger.
2 is a schematic diagram illustrating one embodiment of the present invention in which a finger in contact provides a capacitive link between sensing conductors on a grid.
3 is a circuit diagram illustrating an electrical theory of the embodiment of FIG. 2 of the present invention.
4 is a schematic diagram illustrating an embodiment of the invention in which a finger incident on a conductor floats using a signal oscillating with respect to a reference signal to provide a capacitive path to ground; .
FIG. 5 is a circuit diagram illustrating a version of the embodiment of FIG. 4.
6 is a circuit diagram illustrating a modification of the embodiment of FIG. 4.
FIG. 7 is a circuit diagram illustrating another example in which the conductor is directly vibrated.
FIG. 8 is a circuit diagram illustrating a variation of the embodiment of FIG. 7 in which the conductor vibrates from its remote ends. FIG.
FIG. 9 is a block diagram illustrating the separation provided by the DC-DC converter as a variant of the embodiment of FIG. 4.
FIG. 10A is another block diagram of the embodiment of FIG. 4, showing that separation by a DC-DC converter is provided between two portions of the detector. FIG.
10B is a block diagram illustrating a variation of the embodiment of FIG. 10A to allow communication between two portions of the detector.
11 is a block diagram illustrating coil based separation of a detector according to an embodiment of the present invention.
FIG. 12 is a block diagram illustrating a coil based branch being used for a portion of the detector as a variant of the embodiment of FIG. 11.
FIG. 13 is a block diagram illustrating the floating of a detector by placing a tandem oscillator on the anode and ground power rails.
14 is a schematic block diagram illustrating how the same excitation circuit can be used for stylus and finger contact in accordance with a preferred embodiment of the present invention.
15 is a theoretical circuit diagram illustrating a source of steady state noise that affects contact measurements in embodiments of the present invention.
16A and 16B show tabulation of the conductor grid and both magnitude and phase of the noise effect on each conductor.
FIG. 17 is a block diagram of a touch detection apparatus that may use the tablet of FIG. 16B to correct a contact reading. FIG.
18 is a schematic diagram illustrating a signal pattern representing finger contact.
19 is a schematic flow chart illustrating a contact measurement procedure in accordance with the present invention.
Embodiments of the present invention include a digitizer capable of finger click and movement detection on a flat panel display in such a way that the same sensing infrastructure can be used for electromagnetic (EM) stylus detection. . The digitizer is designed to operate in conjunction with a patterned transparent foil system, which can detect the position of the electromagnetic stylus on the surface of the electronic display screen. Some preferred embodiments of the present invention use a finger induced capacitance connecting sensor line as a finger contact detection method. This embodiment particularly includes a method of identifying the presence and location of a finger by measuring a differential signal between two different sensor antennas. In a preferred embodiment, current is driven from the end of the antenna and then the information is sensed and digitized using a detector as described in detail below.
While the prior art teaches connecting each charge sensor or the like to each electrode, the present embodiment can use the difference signal generated between the two electrodes.
One method described herein includes measuring a voltage difference by a finger adding a capacitive short circuit to ground.
The preferred and preferred embodiment of the "on-screen-keyboard" in a device, such as a tablet PC, in addition to or in parallel with the operation of the correct electromagnetic stylus, is a natural and intuitive. It can work.
In the following description, three methods of realizing a contact sensor using the same detector device and sensor grid used for detection of an EM stylus are described. The sensing method described may require adjustment for a given environment and device, which will be apparent to those skilled in the art. However, all methods are simultaneous and independent of the EM stylus in a manner similar to that disclosed in U.S. Patent Application No. 10 / 649,708 of the same assignee as the present application of August 28, 2003, in which the U.S. claims priority to Patent Application No. 60 / 406,662. It is designed to enable detection. Detection of finger contact and EM stylus is independent and can be performed simultaneously or at different times. The user can determine whether to use the detector for only one type of interaction (ie, finger contact or EM stylus) or the embodiment disclosed herein for the detection of two types of interaction.
In a preferred embodiment of the present invention, the same detector can detect and process signals from the electromagnetic stylus whether or not the electromagnetic stylus is in contact with or at a short distance from the surface of the flat panel display. For example, the detection is described in "Physical Object Location Apparatus and Method and a Platform using the same" of U.S. Patent Application Serial No. 09 / 628,334 to N-trig Ltd and U.S. Patent Application Serial Number 09 /, also assigned to N-trig Ltd. 628,334, "Transparent Digitizer". At the same time the detector can be used to detect a user's finger located on the same display as described below. In another embodiment of the invention, finger detection functions alone or in combination with any other input device.
The principle and operation of the digitizer according to the present invention will be better understood with reference to the drawings and the accompanying description.
Before describing an embodiment of the present invention in detail, it should be understood that the present invention is not limited to the details and arrangements of the components shown in the following description or the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. It is also to be understood that the style or terminology used herein is for the purpose of description and not of limitation.
1A, there is shown a schematic representation of a general embodiment of the present invention, in which the sensor 2 has at least one electrical conductor 4. In a typical case, one or more conductors are used, and these conductors are arranged on a sensor or in a pattern, most often provided as a grid extending over a surface such as an electronic screen that requires touch sensing. The detector 6 extracts the output from the conductor. The oscillator 8 supplies oscillation or alternating energy to a system comprising a sensor and a detector. In one embodiment, the system is not initially AC coupled. However, since a conductive object including a body part such as a finger is capacitive, such a contact can be sensed by making an AC coupling in the system by using a finger or the like. The finger contact also provides an alternating current short circuit to ground for a given conductor so that the touch can also be detected.
Preferred embodiments detect the contact as described above and additionally allow for the positioning and identification of a physical object such as a stylus. The position of the physical object is preferably detected by an electromagnetic transparent digitizer configured on the surface of the display, since the electromagnetic transparent digitizer uses components such as the contact digitizer described herein, so that two types of detection are performed as described in detail below. It is a feature of some preferred embodiments that can be incorporated into the digitizer. A preferred configuration of an electromagnetic transparent digitizer is described in US patent application Ser. No. 09 / 628,334, which describes a sensing device capable of detecting a plurality of physical objects located on the surface of a flat panel display.
Specifications of various parts and functions of the transparent digitizer are as follows.
As described above in reference to the above applications and as used in the preferred embodiment, the sensor has two transparent foils, one with a set of vertical conductors and the other with a set of horizontal conductors. The grid of conductor lines is made of a conductive material patterned on a transparent foil, which may for example be a PET foil.
Further information regarding the construction of the sensor can be obtained from US Provisional Patent Application No. 60 / 406,662 (subchapter 4.2 entitled "Sensor") and corresponding US Patent Application No. 10 / 649,708, filed August 28, 2003, All these applications have been assigned to N-Trig.Ltd., Which is hereby incorporated by reference.
b. Front end devices
As described in the above applications and used in the preferred embodiment, the detector has a front end device in the first stage where the sensor signal is processed.
The functions of the front end device are as follows.
The differential amplifier amplifies the signal and sends the result to the switch. The switch selects the received input that appears to require further processing. In other words, the switch filters out inputs that are considered to be inoperative. The selected signal is amplified and filtered by the filter and amplifier device prior to sampling. The output of the filter and amplifier device is then sampled by an analog to digital converter and sent through a serial buffer to the digital device.
For further information, see US Provisional Patent Application 60 / 406,662 (subchapter 4.3 entitled “Front End”) and corresponding US Patent Application No. 10 / 649,708, filed August 28, 2003, all of which are incorporated herein by reference. Was transferred to N-Trig.Ltd., Which is hereby incorporated by reference.
c. Digital devices
As described in the above applications and used in the preferred embodiment, there is provided a digital device, i.e., a microprocessor, having the following functions.
The front end interface receives serial inputs of sampled signals from various front end devices and packs them in parallel representations.
A digital signal processor (DSP) core, which executes the digital device processing, reads and processes the sampled data to determine the location of a physical object such as a stylus or finger.
The calculated location is sent to the host computer via a link.
For further information, see US Provisional Patent Application 60 / 406,662 (subchapter 4.4 entitled “Digital Devices”) and corresponding US Patent Application No. 10 / 649,708, filed August 28, 2003, all of which are incorporated herein by reference. Was transferred to N-Trig.Ltd., Which is hereby incorporated by reference. The above application describes signal processing and position determination for signals coming from the electromagnetic EM stylus but does not discuss finger contact detection. As described below, in the present embodiment, finger contact can be detected using a suitable signal on the same conductor that is processed in substantially the same manner. Whether signals come from a finger or stylus does not make a substantial difference to the DSP core or the intervening electronics.
The detector constitutes a digital device and a front end device as described above.
As described in the above applications and used in the preferred embodiment, simultaneous and separate inputs from either the stylus or finger can be detected.
A preferred embodiment of the present invention utilizes a passive EM stylus that includes a resonant circuit. An external exciting coil surrounding the sensor excites the resonant circuit inside the stylus. The resonant circuit emits radiation that can be detected by the conductor. The exact position and unique ID of the stylus can then be determined by the detector according to the processing result of the signal sensed by the sensor.
For further information, see US Provisional Patent Application No. 60 / 406,662 (subchapter 4.5 entitled “Stylus”) and the corresponding US Patent Application No. 10 / 649,708, filed August 28, 2003, all of which are incorporated by reference. It was transferred to N-Trig.Ltd., Which is hereby incorporated by reference.
In a preferred embodiment of the present invention, the basic detection operation cycle consists of averaging, attenuation compensation, windowing, FFT / DFT, peak detection, interpolation, error compensation, filtering and smoothing. This cycle is the same regardless of the finger contact or stylus being detected, with the exception of the notable exception that the appropriate error compensation type varies depending on the noise source as described below.
For further information, see U.S. Patent Application No. 60 / 406,662 (subchapter 4.6 entitled "Algorithm") and the corresponding U.S. Patent Application No. 10 / 649,708, filed August 28, 2003, all of which apply. It was transferred to N-Trig.Ltd., Which is hereby incorporated by reference.
3. Finger touch detection
This method utilizes electromagnetic waves transmitted from external sources or by sensor components and received by the user's body. When the user's finger touches the sensor, EM energy is transferred from the user to the sensor. The detector processes this signal and determines the position of the finger.
Referring now to FIG. 1B, which shows a general description of a first finger touch detection apparatus according to the present invention. The external device 10 transmits electromagnetic wave energy absorbed by the user's body. When the user touches the sensor 12, a capacitance is formed between the finger 4 and the sensor conductor. The received signal is generally at a frequency that allows the signal to pass through the capacitance at the formed level so that the received signal is transmitted from the user's finger to the sensor 12. The detector 16, which processes the sensed signal, determines the position of the user's finger.
In a preferred embodiment, an external energy source is generated internally by a system using a dedicated transmitter. In other embodiments, the energy source may be side effects of other parts of the system, such as the transmitter of the DC-DC converter, or may be background noise that is not entirely related to the system, such as electronic network noise.
In a preferred embodiment, the same sensor conductor used to sense the EM stylus also senses the signal transmitted by the user's finger. In addition, the analog processing of the signal and the sampling of the signal are similar to that of the EM stylus and are performed by the same hardware as described elsewhere in this specification. In other embodiments it is desirable to use different conductors for sensing the finger and stylus respectively, so that other electronic devices are added along with the stylus sensing device to process and sample the finger signal.
In the preferred embodiment, the EM stylus signal and the user finger signal are both received and processed simultaneously, so that two types of input can be detected at once. This is possible because the types of input signals received from the sensors are substantially the same, as described elsewhere herein. In another embodiment, the system can alternate between detecting a finger and a stylus.
The sensor requires a reference voltage level and a convenient reference is ground. However, in a preferred embodiment of the present invention, the sensor reference is separated from the electronic network ground. The reason is that while ground is used, the electrical potential of the user's body is close to the potential of the sensor reference and as a result the sensed signal is low. As the reference moves from ground, the sensed signal is increased.
In another embodiment, the sensor reference may be connected to the ground of the electrical network, even if a dedicated transmitter is used. That is, the system as a whole can be operated whether or not the system is connected to ground. However, if the system is connected to ground, it is desirable to use a dedicated transmitter. This is because if a dedicated transmitter is not used in the grounding system, the signal from finger contact is weak and difficult to detect.
As described in detail below, the finger contact position is determined by processing the corresponding magnitude (and phase) of the signal detected on both axes. Accurate positioning is calculated by interpolation type processing of signals sensed by other conductors close to the finger contact point.
In a preferred embodiment, the signal is transformed from the time domain to the frequency domain. If the energy received by the user's body is concentrated at a particular frequency, processing is performed at that particular frequency and other frequencies are simply ignored. Otherwise, processing may be performed for the group of frequencies.
In a preferred embodiment, different conductors are sampled in different time slots. The size of the time slot is chosen small enough so that the characteristics of the signal do not change in several time slots. Nevertheless, however, if the signal changes between successive measurements, such as a finger receiving random noise, in this embodiment the measurement procedure changes and all the conductive lines are sampled simultaneously.
In a preferred embodiment, the energy transfer source is external to the sensor. In another embodiment, energy is delivered by one of the sensor components, such as, for example, a sensor excitation coil, a sensor matrix, or any other conductor, which is added to the sensor in particular to deliver energy. In a preferred embodiment, alternating energy can be transferred between a first transmitter orthogonal to one set of sensing conductors and a second transmitter orthogonal to another set of conductors. With respect to the concept of a transmitter orthogonal to a conductor, when transmitting a signal from an antenna that is orthogonal to one conductor axis and parallel to another conductor axis, the signal received on the parallel conductor is so strong that no signal derived from the finger is detected. However, conductors orthogonal to the transmitting antenna are hardly disturbed by the antenna. Thus, the signal induced by the finger can be detected on the conductor orthogonal to the transmitting antenna. In all preferred embodiments, electromagnetic (EM) stylus excitation is performed before sampling, while finger detection energy is transmitted during sampling. In conclusion, it is possible to produce both a stylus woman and a finger woman. That is, in other words, transmission, that is, a signal can be generated using the same hardware such as a signal generator. The two signals are simply transmitted by the same physical antenna in different time slots. The stylus sampling procedure also includes an excitation period and each sampling period accompanying the excitation period. Thus, while the stylus is being sampled, the antenna can already start generating signals for finger detection. Thus two objects can be detected at the finger excitation stage. Alternatively, the stylus excitation signal generator may also be provided as a separate device from the finger detection signal generator.
In a preferred embodiment, the detector can detect multiple finger contacts simultaneously. If different conductors detect different fingers, detection of multiple fingers is similar to detection of one finger. However, if more than one finger is detected by the same antenna, a strong signal magnitude is sampled on each antenna. The detector simply needs to process the magnitude of the signal to distinguish between multiple finger contacts.
The disadvantages of the first embodiment are as follows.
• The signal provided by the fingers is significantly reduced when the system is grounded. These shortcomings make digitizers operating on a system primarily suitable for battery powered devices or devices powered by a source that is highly separated from ground.
Thus requiring transmission and thus potentially interfering with other defenses.
Distance dependence from user to transmitter; The further the transmitter is from the user, the lower the signal. The resulting variation can lead to reliability problems.
The second embodiment does not need to send an EM signal to the user's body. Instead, the user's finger adds capacitance connecting two orthogonal sensor lines even without the effect of the EM signal.
Referring now to FIG. 2, this diagram illustrates a general description of a second, finger detection embodiment of the present invention. A two-dimensional sensor matrix 20 is placed on the transparent layer over the electronic display. Electronic signal 22 is applied to first conductor line 24 in two-dimensional sensor matrix 20. There is any minimum amount of capacitance at each junction of the two conductors. The finger 26 contacts the sensor 20 at an arbitrary position, increasing the capacitance between the first conductive line 24 and the orthogonal second conductive line 28 at or closest to the contact position. Let's do it. Since the signal is alternating, the signal crosses the signal from the first conductive line 24 to the orthogonal conductive line 28 by the capacitance of the finger 26 and the output signal 30 can be detected.
Depending on the size of the finger and the fineness of the conductor's meah, it is understood that any number of orthogonal conductors can receive any capacitive signal transmission, and interpolation of the signals between the conductors can be used to improve the accuracy of the measurement. Could be.
It will also be appreciated that capacitive coupling of this nature generally results in phase shifts in the signal. The importance of the phase shift is described below.
Referring to FIG. 3, the theoretical equivalent electrical circuit diagram of FIG. 2 is shown. The same parts as the previous drawings are given the same reference numerals and are not mentioned again except as necessary to understand the present invention. The transmission signal 22 is applied to the horizontal conductor 24. The finger 26 in contact with the sensor creates two capacitors C1 40 and C2 42 that transmit signals from the horizontal line to the finger and from the finger to the vertical conductor 28. The output signal 30 is detected at the edge of the vertical conductor in case of finger contact.
In a preferred embodiment, the two-dimensional matrix of conductors used to sense the stylus is the same as that used to sense the finger. Each conductive line is used to receive both the stylus signal and the finger signal. Each line may serve to receive or inject a signal. The detector controls the switching of the sensor conductors between the receive and transmit modes.
Each horizontal conductor overlaps each vertical conductor and the overlapping region between the horizontal and vertical conductors generates any amount of parasitic capacitance. Each junction also provides a different level of capacitance. Capacitance allows small amounts of signal transmission between conductors even when no fingers are present. In a preferred embodiment, the detector actually learns the amount of parasitic current transfer for each junction and subtracts this value from the sampled signal.
The goal of the finger touch detection algorithm in this method is to recognize all sensor matrix junctions that carry signals due to external finger contact. It should be noted that this algorithm is preferably able to detect more than one finger contact at a time.
There may be a number of procedures for detection. The simplest and direct way is to provide a signal to one of the matrix lines of one matrix axis one line at a time and read the signals sequentially from one matrix line on the orthogonal axis. In this case, the signal may be a simple cosine pattern of any frequency within the sampling hardware and detection algorithm range. If a valid detection signal is detected, this means that there is a finger in contact with the junction. The contact being contacted is currently excited with input It is a part which connects a conductor and the conductor from which an output signal is detected. The disadvantage of this direct detection method is that it requires nearly n * m steps, where n represents the number of vertical lines and m represents the number of horizontal lines. In practice, the number of steps above is usually at least 2 * n * m steps since it is usually necessary to repeat the procedure for the second axis. However, this method can detect a large number of finger contacts. If the output signal is detected more than once, there is one conductor which means more than one finger contact. Junction contacted current It is a part which connects the conductor which is excited and the conductor which shows an output signal.
A simple way is to apply a signal to a group of conductors on one axis. The group includes any subset that includes all conductors on that axis and searches for signals on each conductor on the other axis. The input signal is then applied to a group of lines on the second axis and the output is searched on one conductor on the first axis. This method requires a maximum of n + m steps, and if the group is on the entire axis, the number of steps is two. However, if multiple contacts occur simultaneously in a specific combination of positions, this method is rare but obscure, and the larger the group, the larger the obscure area.
An alternative way to start with the simple method above and switch to the direct method upon detection of possible ambiguity is to combine the above methods.
The third embodiment uses the potential difference between the user finger and the system to determine finger position.
Referring now to FIG. 4, this figure shows a schematic diagram representing a third preferred embodiment of finger contact detection of the present invention. The detector 60 is connected to ground 62 and the detector is connected to an oscillator 64 that provides an alternating signal that causes the detector potential to vibrate with respect to the ground potential. The oscillation potential is applied to the sensor 66.
In operation, the detector 62 oscillates with respect to the common ground potential. When the user's finger 68 contacts the sensor 66, a capacitance is formed between the finger and the sensor conductor. The user's body potential now does not vibrate with respect to earth (ground), but the potential of the sensor vibrates with respect to the common ground potential. Thus, an AC potential difference is formed between the sensor and the user. Thus, alternating current passes through the finger from the sensor to ground. The current is repeated as a signal passing from the user's finger to the sensor 66. The detector 62 processes the sensed current and determines the position of the user's finger according to the magnitude, i.e. signal level, on any sensor conductor. In particular, there is a potential difference between the sensor and the finger (referred to as V), and the finger contact itself includes capacitance C, so that there is a charge transfer of size Q = C * V between the finger and the conductor. This charge transfer can be derived from the current on the conductive line.
The common ground can be electronic circuit ground, but the method works when the system is not actually connected to ground but is connected to the common ground of each system, such as flat panel displays, tablet PCs, and the like. The above system has sufficient capability to allow the detector to oscillate with respect to a common ground.
In some embodiments the system oscillates normally with respect to a common ground, but in a preferred embodiment the system oscillates only a portion of the time. That is, it only vibrates when the signal is actually received and processed by the detector. In other words, when there is no incoming signal to be digitized, the system stores energy by not operating the oscillator.
Referring now to FIG. 5, shown is a circuit diagram of an embodiment of the embodiment of the invention shown in FIG. 4. Portions like FIG. 4 are given the same reference numerals and are referenced only when necessary to explain the theory of operation of the embodiment. In Fig. 5, the oscillator 64 is connected between the ground 62 and the detector 60. The oscillator 64 vibrates the detector front end, which includes the detector 60 and two sensors 70 and 72, the two conductors being connected to the differential input of the differential amplifier 74, respectively. As mentioned above, all vibrations occur with respect to the common ground potential 62. The capacitance 76 is generated by the contact of the sensor conductor, ie, the finger of the user, with the user's finger. If there is a potential difference between the conductor 70 and the user, current flows from the conductor 70 to ground through the finger. Impedance 78 represents the impedance of the finger. As a result, a potential difference occurs between the conductor 70 and the conductor 72. Preferably the distance between two conductors 70,72 connected to the same differential amplifier is greater than the width of the finger so that the required potential difference can be formed. The differential amplifier 74 amplifies the potential difference, and the detector 60 processes the amplified signal to determine the position of the user's finger. It should be noted that in other embodiments the sensor is connected to a standard amplifier rather than a differential amplifier.
If the oscillator is not used and a direct current is generated, the measurable potential difference is created by the contact of the finger since the finger contact induces capacitance and does not affect the direct current.
In a preferred embodiment of the present invention, as described above, the entire detector is vibrated with respect to a common ground. The disadvantage of this choice is that any communication between the detector and the outside world, such as serial communication to the host computer, must be made to compensate for the potential difference between the detector and the outside world and cannot use common ground. There are a number of ways of communicating between parts that must be isolated from one another, for example an example of how to provide isolated communication is to use a selection link. The select link converts the electrical signal to light and then back to the electrical signal so the isolation level is very high. However, the need for separation can also be overcome by applying an oscillation to only part of the detector.
Referring to Fig. 6, a theoretical circuit diagram showing a detector in which vibration is provided in part is shown, where like parts in the previous figures are given the same reference numerals and are not referred again except as necessary to understand the present invention. Detector 80 is identical to detector 60 except that it is divided into two devices 82 and 84. Oscillator 86 is located between two devices 82, 84 in detector 80.
The oscillation state of the detector component is as follows.
1) The device 82 of the detector 80 does not vibrate with respect to a common ground.
2) The device 84 of the detector oscillates with respect to a common ground. Device 84 includes a front end of the detector, and may also include other components of the detector.
The sensor device 88 also oscillates to a common ground by being connected to a detector front end that is part of the device 84. In the figure, the sensor device is made of a transparent film containing a matrix of sensors.
The use of the embodiment of FIG. 6 involving the splitting of the detector into two devices is a choice available to those skilled in the art, selected in any given environment with regard to efficiency, convenience and cost.
When the user's finger contacts the sensor conductor in the sensor device 82, the capacitance 76 is generated as described above. The sensor detects the signal induced by the user's finger on another sensor conductor. The detector 80 including the detector devices 82 and 84 processes the sensed signal and determines the position of the user's finger.
In a preferred embodiment, the fixed portion 82 of the detector 80 communicates with the outside world without requiring any insulation.
An additional advantage of this embodiment is the use of oscillation to increase power consumption. Thus, partial application of vibration results in lower overall power consumption in the system.
It is a requirement of the present invention to provide communication between two devices of the detector as one vibrates against the other as described above. This problem can be solved in various ways, for example using the following choices.
1. Use different signals to output data on two parallel lines, one as a signal and the other as a reference. Both the signal and its reference oscillate, but the data is actually carried in the difference between the two. This embodiment is described in detail below with reference to FIG. 10B under the heading “floating the system”.
2. Uses electrical separation communications within the detector, such as photo-isolators.
3. Restriction of communication to the time slots in the oscillation phase when the front end portion does not vibrate against other parts of the system or when the two are balanced.
Reference is now made to FIG. 7, which is a schematic theory circuit diagram illustrating a preferred embodiment of the present invention. In the embodiment of FIG. 7, oscillation is applied to the sensor, in particular the conductor of the sensor, but not to the detector.
In FIG. 7, oscillator 90 provides an oscillation signal with respect to ground 92. This oscillation signal is provided to the sensor as a reference signal Vref and in particular to each conductor in the sensor, ie Vref is provided to each conductor, respectively.
In the figure, two sensors 96 and 98 are shown connected to the differential input of a single differential amplifier 100. Capacitors 102 and 104 are connected between each sensor line and the corresponding differential input. Finger 106 is then applied to one of the conductors.
In the embodiment of Fig. 7, the reference signal Vref is applied to each conductor at the output stage, i.e. at the connection to the differential amplifier and more particularly at the amplifier side of the separate capacitors 102,104. Thus, excitation and sampling are performed at the same end of the conductor, which is the input to the differential amplifier.
In use, vibration is applied to the sensor conductor by vibrating the reference quasi-pressure Vref applied to the sensor.
Oscillator 90 vibrates Vref 94 with respect to common ground 92. Thus, conductors 96 and 98 also vibrate with respect to network ground. Capacitors 102 and 104 filter out irrelevant low frequencies from conductors 96 and 98. Unless the user touches the sensor, the signal received at the two inputs of the differential amplifier is similar, so no output is generated. When the user's finger 106 contacts the conductor 98, capacitance is generated between the user's finger 106 and the conductor 98 as before. The amplitude and phase of the signal propagating through the contact conductors change due to the added capacitance. The potential difference between the conductor 98 and the conductor 96 is amplified by the differential amplifier 100 and then processed by the detector to determine the position of the user's finger.
Referring to FIG. 8, there is shown a schematic representation of a variant of FIG. 7, where like parts are designated by like reference numerals and are not referred again except as necessary to understand the invention. In the embodiment of Fig. 8, two reference signals are used and the oscillation reference signal Va is applied to the conductors on both ends extending towards the opposite sensor on which the detection is performed, which is spaced from the input to the differential amplifier. Is different from FIG. 7. A direct current reference signal is applied to the output of the conductor and used to generate a high reference level for the conductive line. Another embodiment does not include a separate direct current reference signal Vref and depends only on Va. Vref is used in this embodiment and produces a high reference level for the conductor. That is, because the input resistance to the amplifier is very high, the conductor is sensitive to noise from the outside. Connecting the conductor to a high reference level eliminates or at least reduces the propensity to take noise. In the embodiment of Figure 7, the Vref signal is used to vibrate the conductive line and set the DC level. In the embodiment of Fig. 8, it is clear that vibration can be applied opposite to the detection end of the conductor, and that the oscillation and direct current reference signals can be separated. It should also be noted that Va can be applied without using a separate Vref signal.
In use, oscillation is applied to the sensor conductor by vibrating the reference voltage Va 110 applied to the sensor.
Oscillator 90 vibrates Va 110 with respect to common ground 92. Thus, conductors 96 and 98 also vibrate with respect to network ground. Capacitors 102 and 104 filter out irrelevant low frequencies from conductors 96 and 98, respectively. Unless the user contacts the sensor, the signals received at the two inputs of the differential amplifier are similar and no output is generated. When the user's finger 106 contacts the conductor 98, a capacitance is generated between the user's finger 106 and the conductor 98 as before. The amplitude and phase of the signal propagating through the contact conductors change due to the added capacitance. The potential difference between the conductor 98 and the conductor 96 is amplified by the differential amplifier 100 and then processed by the detector to determine the position of the user's finger.
In order to vibrate the system or part thereof with respect to a common ground, the system or part thereof preferably has a specific isolation level from ground. The better the isolation level, the lower the power loss due to vibration.
Referring now to FIG. 9, there is shown a schematic diagram showing an arrangement for floating the detection system of the present invention using a DC-DC converter, in which the detector 120 is an isolated DC-DC converter 124. It is connected to the ground 122 through. Oscillator 126 provides a reference voltage thereto to oscillate the isolated detector 120.
The DC-DC floating method can be modified to vibrate only one detector with respect to ground. Two of these modifications are shown in FIGS. 10A and 10B. Referring to FIG. 10A, the detector 120 includes two devices 131, 134, the isolated DC-DC component 136 causes the detector component 134 to float to ground, and the oscillator 138 has a common ground. The detector device 134 is vibrated with respect to 140.
Since one detector device 134 vibrates while the other detector device 136 does not vibrate, communication problems arise between the two detector devices 132, 134.
Referring to Figure 10b, a solution that can solve the aforementioned communication problem is shown. The same parts as in FIG. 10A are given the same reference numerals and are not referred again except as necessary to understand the present invention. The detector device 134 floats with respect to ground and vibrates by the oscillator 136. The output signal of the detector device 134 vibrates in phase with the oscillator 136. The output signal 142 and the oscillator output 144 from the detector device 134 are input to the differential amplifier 146. The potential difference between the signal 142 and the signal 144 is amplified by the differential amplifier 146. The output signal of differential amplifier 146 is a normal signal representation of signal 142. Accordingly, detector devices 132 and 134 may communicate through differential amplifier 146 serving as a communication device or channel.
Referring now to FIG. 11, there is shown an embodiment using a coil to separate the system, generally the coil has a low impedance for low frequencies and a high impedance for high frequencies. The power supply is provided in a separate part using low frequencies close to direct current, but the coil manages the separation of high frequencies, such as those used to vibrate the detector. In FIG. 11, detector 150 is separated from its power source and common ground 152 using two coils 156 and 158. Oscillator 154 vibrates detector 150 with respect to a common ground.
Referring now to FIG. 12, here a floating coil scheme is implemented such that only one detector vibrates with respect to a common ground, where the detector is divided into two devices 162 and 164. The device 162 is separated from its power source and common ground 166 using two coils 168, 170, and the oscillator vibrates the device 162 with respect to the common ground.
Referring to FIG. 13, an additional method of applying vibration to the system and portions thereof with respect to a common ground is shown. In the embodiment of FIG. 13, the detector 180 includes a first oscillator 182 and a second oscillator 184. Is connected to. The first oscillator is connected to the + power supply line and the second oscillator is connected to the ground line. In use, the detector device to which vibrations are applied is not isolated and remains non-floating. Instead, the second oscillator 184 vibrates at the low potential of the system VSS with respect to common ground, and the first oscillator 182 vibrates with the high potential of the system VCC with respect to the power supply DC level. Unless two oscillators are synchronized in phase and magnitude, the detector or one detector oscillates with respect to a common ground.
As mentioned above, several preferred embodiments of the present invention utilize an oscillator to provide a transmission signal and oscillate one detector or some or all sensor conductors. The following section describes some options for the implementation of such an oscillator.
One preferred embodiment uses a stand-alone oscillator. These standalone oscillators can oscillate at a single frequency or at a variable frequency. In the latter case, the variable frequency is determined by the DSP component of the digital device associated with the digital system.
Further embodiments use the DSP itself to generate oscillations. The advantage of this method is that the vibration phase can be easily synchronized for sampling. In this case, the DSP signal value is provided to a D2A (digital-analog) component or any equivalent device and then the analog value is filtered and amplified as needed. Another variant of this embodiment may use parts such as those used for the excitation of the stylus for the generation of vibrations. For details of the woman of the stylus, see FIG. 9 of US Provisional Patent Application 60 / 406,662 and the corresponding description entitled “Stylus”. The above drawings and corresponding descriptions are referred to here.
The same parts can be used for stylus excitation and finger sampling for the following reasons:
The finger is detected only during the dedicated sampling period, and
● Excitation is not executed during this dedicated sampling period.
Referring now to FIG. 14, there is shown a schematic diagram illustrating the foregoing use of a stylus excitation component to realize an oscillator, where DSP 190 generates a digital signal, and D / A converter 192 converts this signal to analog. Convert to display. An amplifier 194 connected downstream of the D / A converter amplifies the analog signal, and the switch 196 transmits this signal to the excitation coil 198 or to each embodiment for stylus excitation as needed in each embodiment. Supply to the oscillation output 200 to provide the oscillation signal required for. Note that the switch can be placed before the amplifier if different levels of amplification / output impedance are needed for the two tasks.
Irrelevant "normal noise" problems and their solutions
Unrelated "normal noise" problem on the display panel
Referring to Fig. 15, a schematic diagram is shown which is referred to as a display panel signal problem, in which two sensor conductors 210 and 212 vibrate with respect to ground 214 by the embodiment described above. As mentioned above, the sensor is located above the electronic display. Capacitances 216 and 218 are generated between the conductors 210 and 212 and the display panel 220. Since the display panel electrically represented by the resistor 220 does not vibrate with respect to the common ground 214, two signals Sa and Sb, which can be regarded as vibration leakage currents, are provided to the conductors 210 and 213, respectively.
Unless the oscillation phase and magnitude change, Sa and Sb remain the same over time. Therefore, Sa and Sb are referred to herein as normal noise. It should be noted that parasitic capacitances on sensors and displays may also change due to environmental conditions, and this change may also affect the signal.
In an ideal environment, there is no signal difference amplified by the differential amplifier 222, which is connected between the two sensors 210,212, as long as Sa = Sb and thus the user's finger is not in contact with the conductor. In practice, however, there are some differences in distance, overlapping area, screen structure, media, temperature, etc., resulting in Sa? Sb and thus "normal noise" Sa-Sb. This normal noise is amplified by the differential amplifier 222. This “normal noise” based on Sa and Sb is on two sensor conductors connected by a differential amplifier so that a similar difference for Sa-Sb is amplified by any differential amplifier connecting the sensor conductors in the system. This results in several amplified normal noises that are constant in time but detected by the detector. This normal noise lowers the level of accuracy at which the position of the user's finger can be detected.
Referring now to FIG. 16, FIG. 16 includes 16a, the upper portion of the display panel as grid 230 of sensor lines 232, with each pair of sensor lines connected to a differential amplifier 234. In a preferred embodiment of the present invention, the solution to the above problem is to map the various panel display amplified signal differences. As shown in Fig. 16B, normal noise values are determined and mapped for each pair of sensor conductors. This mapping is preferably done as follows.
Sa is "normal noise" generated on the sensor conductor connected to the anode of the amplifier by the flat panel display, and Sb is "normal noise" generated on the second sensor conductor connected to the cathode of the amplifier by the flat panel display. The differential amplifier connects two conductors. The difference between Sa and Sb is amplified by a differential amplifier.
1. The amplified signal is converted into a digital display by A / D.
2. The DSP performs the FFT / DFT on the digital signal.
3. Operation 1-3 is repeated for a predetermined number of times (for example 20 times). Averaging is then performed. Averaging minimizes variable noise that can provide temporary distortion of the measurement. The mean value is then stored in the difference map.
4. Operations 1-4 are performed for each pair of conductors connected by a differential amplifier.
This result is a map, referred to herein as a difference map, represented by FIG. 16B which includes the magnitude and phase of the difference signal recorded for each sensor pair. Each recorded magnitude and phase pair represents the display panel "normal noise" of each pair of sensor conductors connected by a differential amplifier. Magnitude and phase are used for specific oscillation frequencies.
In a preferred embodiment, the system uses a single frequency for finger contact detection, but in further embodiments, more than one frequency can be used, and the system can switch between frequencies and oscillate simultaneously on more than one frequency. Can be. If more than one frequency is used, more than one map is generated. Preferably one map is generated for each frequency.
Once the difference map is stored in memory, it can be used to compensate for the display panel signal normal noise phenomenon. Reference is now made to FIG. 17, which is a schematic diagram showing two conductor sensor arrays representing a normal noise phenomenon. The display panel generates "normal noise" Sa and Sb on sensor conductors 240 and 242, respectively. The user's finger produces an Sf signal, which is the signal required for the measurement. The total difference determined by the differential amplifier 244 between the sum of the signals on the two sensor conductors is {(Sa + Sf) -Sb}. The total difference is amplified by differential amplifier 244 and sampled by detector 246. The DSP component 248 reads the difference Sa-Sb stored in the difference map. DSP 250 subtracts the difference from the sampled signal. When (Sa + Sf) -Sb- (Sa-Sb) = Sf, the DSP can separate and identify the finger signal and identify the position of the finger.
This mapping process is used in the preferred embodiment of the present invention to solve the problem of normal noise injected by the panel display. The method may be used in the same and other embodiments of the present invention to solve any kind of normal noise problem. Examples include potential sources of normal noise, including differences in input impedance, differences in input capacitance, and inadequate common mode rejection.
Signaling object detection problem and solution by mapping process
The mapping process creates the following problem.
Object Typically, a finger, hand or combination of fingers and hands located on the display panel generates a signal during the mapping process. When the hand is removed, a difference between the values initially stored in the difference map is created. This difference may be misinterpreted by the DSP 248 as a correlation signal such as a finger signal.
For simplicity of explanation, the opposite case is taken where the user's finger may be placed on the display panel during the actual mapping process. The finger inputs the signal F1s to the sensor conductor 242 as before. Another sensor conductor 240 receives the normal noise signal D2s from the display panel. These two sensor conductors are connected to the same differential amplifier 244. The other sensor conductor 240 generates a normal noise signal D2s from the display panel. These two sensor conductors are connected to the same differential amplifier 244. The difference received and amplified by the differential amplifier is (D1s + F1s)-(D2s). Sometimes a finger is removed after the mapping process ends. The new difference amplified is D1s-D2s. The DSP subtracts the value stored in the difference map from the new value. The result is (D1s-D2s)-{(D1s + F1s) -D2s} =-F1s. In practice, F1s represents magnitude, and the minus sign represents phase. This result is exactly the expected difference, assuming that the finger is located on the second sensor conductor and the finger is not located at the first sensor during the first mapping process. The DSP responds as if a finger was detected even if the finger was not actually located on the display panel.
One embodiment of the present invention utilizes the foregoing embodiment, which performs the mapping process once during the manufacturing process. The problem is solved when the expected signaling object that generates detection of the signaling object through the mapping process problem described above is the user's finger (s), palm, fist, etc. and the manufacturing environment is an environment without the user.
A disadvantage of this method is the reliability of a single mapping process. Due to the mobility of the system, temperature changes, mechanical changes, etc., the difference between the signals generated by the display panel in the two sensor conductors connected to the differential amplifier can change over time and the recorded difference map becomes invalid. (obsolete). While a tightly controlled manufacturing process can eliminate the above drawbacks by not making such a change, this process adds cost. On the other hand, it is reasonable to believe that extreme changes in environmental conditions will not occur during a single operating cycle of the system (i.e. from computer startup to shutdown). Therefore, initializing the mapping process at system initialization is sufficient in most cases.
One embodiment of the present invention includes performing mapping during each system initialization. During initialization, the user may be warned not to touch the display panel by captions on the display panel or otherwise. When the expected signaling object is a typical user's finger (s), palm, fist, etc., the above warning solves the problem. In a variant, not only is the mapping performed at each initialization, but also there is always a doubt as to the validity of the other map. The method specified to confirm this suspicion is described below.
How to Identify Doubts About the Validity of a Difference Map
In a preferred embodiment of the present invention, simultaneous identification of one or more finger patterns is used to identify doubts about the validity of another map.
Thus, whenever the DSP detects one or more finger patterns, there is doubt about the validity of the difference map and the DSP initiates a new mapping process.
18, an example procedure of the above process is shown. Two groups of three lines are shown, the first group being called Fs and the second group being called PFs. Each line represents two sensor conductors connected to the same differential amplifier. The lines also preferably indicate sensor conductor axial signal detection after subtracting normal noise from any source, such as display panel normal noise, as described above. The height of each line represents the magnitude of the signal. Fs and PFs are finger signal patterns. If the user places a finger on the display panel during the mapping process, the finger signal pattern PFs are detected only once the finger is removed as described above. When the user actually releases the finger, another finger signal pattern Fs is detected. If two finger signal patterns are detected on the same axis, a doubt about the validity of the difference map arises and the DSP initiates a new mapping process.
Note that the same method can be used to identify one or more fingers as well as to identify an object larger than a finger such as a fist or palm. The detection of such object signal patterns immediately raises doubt about the validity of other maps.
Despite the doubt, the disadvantage of the aforementioned method of reinitialization is entering an ongoing reinitialization cycle. Thus, in the example shown in Fig. 18, a new mapping process is started, but the finger that generated the signal pattern Fs at the first position is at that position on the display panel.
An additional disadvantage is that the system can be used alone in a system capable of detecting one finger contact. If the system is designed to detect one or more contacts, the multiple contacts become the correct input signal and cannot be treated as an indication that requires reinitialization.
In another preferred embodiment of the present invention, the detector confirms the doubt of the validity of the other map by using the phase information of the signal. As mentioned above, the phase of the signal generated by the "pseudo" finger is opposite (180 degrees) the phase of the signal generated by the actual finger in the same position. Thus, in a preferred embodiment, the system confirms suspicion by detecting a contradiction between phase and position. However, since the differential amplifier has two inputs, a negative and a positive input, the actual finger located on the other input of the amplifier can also be in reverse phase. Thus, to resolve ambiguity, the system checks the position of the finger without using phase information.
This method is disclosed in US patent application 60 / 406,662, where the amplifier input (negative or positive) is determined using the magnitude of the signal received by the adjacent conductor.
The above method is also described as follows. When a user places a finger on the display panel and then removes it during the mapping process, the finger signal pattern is detected as described above. This method distinguishes the signal pattern from the actual finger placed on the display panel in the following manner. Sometimes after the mapping process a given differential amplifier amplifies the difference in the signals of the two conductors it connects. This difference pattern is suitable for the size of the finger pattern.
The above pattern results in the following scenario:
1. The user's finger is placed on the display panel through the mapping process. This finger sends a signal through the sensor conductor connected to the + input of the differential amplifier, so signal F1s is sent to differential amplifier N. The sensor conductor also receives the normal noise signal D1s from the display panel. In conclusion, the difference received and amplified by the differential amplifier is (D1s + F1s) -D2s. The finger is now removed and the differential signal amplified upon removal of the fingers is D1s-D2s. The DSP now subtracts the value stored in the difference map from the new value. This result is (D1s-D2s)-{(D1s + F1s) -D2s} =-F1s. In practice, the F1s value represents magnitude and the minus sign represents phase shift.
2. The pattern (magnitude and phase) is the result of an actual finger transmitting a current signal through a sensor conductor connected to the-input of a differential amplifier.
Using the received signal magnitude, adjacent conductors, and the method disclosed in subchapter 4.6 of US patent application 60 / 406,662, the DSP detects whether the source is the negative input of the differential amplifier or the positive input of the differential amplifier. It is incorporated here for reference.
• If scenario number 1 applies because the signal source is a sensor conductor connected to the + input of the differential amplifier, the differential map is invalidated and a new mapping process or initialization is started.
If the signal source is a sensor conductor connected to the minus input of the differential amplifier and the scenario number 1 described above does not occur, the mapping is valid and consequently the DSP detects a finger.
This method works the same way when there are two choices:
1. A finger transmits a signal through a sensor conductor connected to the negative input of the differential amplifier, which is then removed.
2. The finger transmits the current signal through the sensor conductor connected to the + input of the differential amplifier.
In order to improve the reliability of suspect detection in the mapping, in the case of using phase information or other methods, the system limits the initialization of relearning normal noise only if such a doubt exists for a certain minimum duration. Since the signal generated by the pseudo finger is stable and does not change over time, stability over time is an additional distinction factor between real and virtual signals.
In a preferred embodiment of the invention, the signal induced by the finger is much larger than the normal noise signal. Therefore, the presence of a finger can always be distinguished from normal noise, so that an accurate mapping process can be executed. For example, returning to FIG. 15, if capacitors 216 and 218 have a lower capacitance than finger induced capacitors, the signal generated by finger contact is greater than the differential signal generated from capacitors 216 and 218. Thus, normal noise resulting from the combination of the sensor array and the display screen cannot be mistaken for finger contact. The detected signal is interpreted as finger contact only if the received signal is significantly larger than normal noise. Under these conditions it is very simple to identify the absence of a finger in the sensor plane to produce an accurate difference map.
One way to create the above condition is to secure an air gap between the conductive line of the sensor and the display screen. By leaving the air gap in the above position, the coupling capacitance between the sensor and the display screen can be reduced to a level where the finger signal is much higher than normal noise. Another method is to position the sensor plane close to the user's finger so that the finger guidance signal ensures more than normal noise.
Referring now to FIG. 19, there is shown a schematic flow chart summarizing an embodiment of the three principles of the invention, in which step 1 is the step of providing an oscillating electrical signal. In one embodiment, the oscillation signal is transmitted and collected by a finger or the like making contact. In the second embodiment, the oscillation signal is provided to one of the two groups of conductors. The oscillation signal can be capacitively coupled to the second group of conductors in the presence of a finger but not in the absence of a finger. In a third embodiment, the detection device or conductor is floated by an oscillation signal and the finger contact provides an alternating current short to ground.
In step S2 the capacitive effect is detected by monitoring the conductors in the grid. In some embodiments, the capacitive effect may be a signal from a finger, a signal drop from another set of conductors or a voltage drop due to an alternating current short provided by a finger connection. In other embodiments, any other capacitive effect may be used.
In step S3 the signal is filtered, and depending on the embodiment, the filtering step can be of different forms, some of which have been discussed in detail above. The signal filtered in step S4 is used to identify whether a contact occurs on the grid.
It is anticipated that many related imaging devices and systems will be developed during the term of this patent, and the terminology used herein, in particular, the scope of "stylus" and "transparent conductive material", is intended to include speculatively all new technologies.
Further objects, devices and features of the invention will be apparent to those skilled in the art in the following example tests, which examples are not intended to be limiting. In addition, each of the various embodiments and features of the present invention described above and claimed in the following claims support the following examples.
It will be appreciated that any feature of the invention described in connection with each embodiment for the sake of clarity may be a combination of one embodiment. Conversely, various features of the invention described in connection with one embodiment for the sake of brevity may be provided separately or in any suitable subcombination.
Although the present invention has been described in connection with specific embodiments, various alternatives, modifications, and variations are apparent to those skilled in the art. It is therefore to be understood that all such alternatives, modifications and variations are intended to be included within the spirit and scope of the following appended claims. The entire contents of all publications, patents, and patent applications referred to in this specification are hereby incorporated by reference to the extent that they appear hereby specifically and individually for each individual publication, patent or patent application. Moreover, citation or indication of any reference in this application is not to be construed as an admission that such reference can be utilized as prior art of the present invention.
A detector for providing a first kind of interaction for position detection on a sensor, with a second kind of interaction for position detection on the sensor,
A patterned arrangement of sensing conductors extending into the sensor, and
A signal relating to the arrangement and resulting from the position detection of the first kind of interaction and the signal resulting from the position detection of the second kind of interaction is detected at the same sensing conductor and from which the position of the sensor is detected. A detector comprising a detection circuit.
Said position detection of a first kind of interaction comprises electromagnetic-based object detection of an object capable of generating an electromagnetic signal.
Said position detection of a first kind of interaction comprises capacitive-based contact detection.
The location detection of the first kind of interaction comprises electromagnetic-based object detection of an object capable of generating an electromagnetic signal, and the location detection of the second kind of interaction comprises capacitive-based contact detection. Characterized by a detector.
And the detecting circuit is capable of detecting the interaction of the first kind of interaction and the interaction of the second kind of interaction at the same time.
And the detection circuitry is capable of independently detecting the interaction of the first kind of interaction and the interaction of the second kind of interaction.
The sensor includes at least one oscillator for providing an oscillation signal to the sensing conductor and an excitation circuit for providing an excitation signal capable of exciting the electromagnetic based object, wherein the detection circuit includes a conductive object such as a finger. And a capacitive effect of detecting the signal from the electromagnetic-based object in the at least one sensing conductor.
And the electromagnetic based object comprises a resonant circuit, wherein the excitation signal is adapted to excite the resonant circuit.
And the object is a stylus.
And the sensor is transparent to be suitable for mounting on a display screen.
And the sensor is disposed above the detection area, wherein the detection area is a surface of the display screen.
The detection circuitry comprises a differential detector arrangement associated with the sensing conductor for detecting the difference between the output signals of the sensing conductors.
And the detection circuitry is configured to detect a signal in at least one sensing conductor induced by the contact of a conductive object receiving the oscillation signal.
The sensing conductor comprises at least one first sensing conductor and at least one second sensing conductor having a junction with the at least one first sensing conductor, the oscillating signal is applied to the first sensing conductor, And a detection circuit is configured to detect a resultant oscillation signal in said second sensing conductor, said result signal being induced by a contact of a conductive object at a junction and estimating said contact therefrom.
And the detection circuitry is configured to detect a signal at the at least one second sensing conductor for analysis as a plurality of contact objects.
Position detection of a first kind of user interaction comprises electromagnetic-based object detection of a plurality of objects, each of the objects capable of generating an electromagnetic signal.
And a plurality of contacts can be detected based on the detected signals.
The oscillator is connected to oscillate at least one of the detector, a portion of the detector and at least one sensing conductor with respect to a reference voltage level to enable capacitive current flow between the conductive contact object and the at least one sensing conductor. Detector.
And the sensor is configured to have a transparent medium between itself and the display screen below.
And the transparent medium comprises an air gap.
A sensor comprising first and second sets of conductor lines forming a grid with a junction therebetween;
A multi-contact detection device comprising circuitry operative to apply signals to conductor lines from one of the first or second set of conductor lines, wherein:
Responsive to a signal applied to at least one conductor line operative to detect an output at conductor lines from said another set of conductor lines, each of said outputs detecting at least one conductor line and output to which a signal is applied; A circuit configured to indicate a level of coupling capacitance formed between conductor lines to be formed;
A detector operative to distinguish between one or more finger contacts simultaneously based on the output;
And said sensor is transparent to be suitable for positioning on an electrical display.
And the detector is operative to determine a location of one or more finger contacts with respect to the sensor.
And said first and second sets of conductor lines are arranged in at least one layer thereof.
And the sensor is comprised of at least one transparent foil patterned with at least one portion of the conductor lines.
Wherein said sensor is comprised of a first layer formed of a first set of conductor lines and a second layer formed of a second set of conductor lines.
And the first and second layers are electrically insulated from each other.
The detector is operative to select one of the first or second set of conductor lines to receive signals applied by the circuit and the other set of conductor lines from which an output is detected. Contact detection device.
And the signal applied to the conductor line is an oscillation signal.
And the detector operates to detect a parasitic current transfer amount for each junction and subtract the transfer amount from the detected output.
Tabulation of leakage capacitance values for each junction, wherein the detector is configured to correct the output detected from the conductor lines using the leakage capacitance value.
The detector initiates the application of a signal from the first or second set of conductor lines to one conductor line at a time, and in response to each signal applied in a plurality of conductor lines from the other set of conductor lines. And a multi-contact detection device operative to initiate detection.
And wherein the conductor lines from each of said first or second set of conductor lines are parallel to each other.
Multi-touch detection further comprising tabulation of the leakage signal generated by the capacitance values for each of the junctions, wherein the detector is configured to use the leakage signal to calibrate the reading at each of the junctions. .
And a compensation table for providing a compensation value for at least one of the conductor lines to compensate for leakage signals resulting from parasitic capacitance values.
The method of claim 69,
And update the compensation table at system start-up.
Providing a sensor comprising first and second sets of conductor lines forming a grid with a plurality of junctions therebetween;
10. A multi-contact detection method comprising applying a signal from said first set of conductor lines to at least one conductor line;
Detecting an output at conductor lines from the second set of conductor lines in response to the applied signal, wherein each of the outputs is at least one conductor line from the first set and conductors from the second set An output detection step responsive to the level of capacitive coupling formed between the lines; And
Discriminating one or more finger contacts interacting with the sensor simultaneously based on the output,
And wherein the detection area of the sensor is transparent to be suitable for positioning on an electrical display.
The method of claim 71 wherein
And wherein the signal applied to said at least one conductor line is an oscillation signal and the outputs detected from said conductor lines are oscillation signals.
Determining a parasitic current transfer amount for each junction and subtracting the transfer amount from the detected outputs.
Determining the tabulation of leakage capacitance values for each junction; And
Correcting the outputs detected from the conductor lines based on the leakage capacitance values.
Applying a signal to one conductor line at a time from the first or second set of conductor lines, and detecting an output in response to each signal applied at a plurality of conductor lines from another set of conductor lines Multi-contact detection method characterized in that.
A method of sensing contact in a matrix-shaped sensing conductor located in a transparent sensor on an electronic display screen, the method comprising:
Providing an oscillation signal to at least one sensing conductor,
Providing the oscillation signal to an external transmitter to excite a conductive object in contact, and
Detecting a capacitive effect on the at least one conductor due to contact with at least one of the sense conductors.
The sensor has a first sensing conductor aligned in a first direction and a second sensing conductor aligned in a direction orthogonal, the method providing an oscillating signal to at least one of the first sensing conductors and contacting a conductive object. Detecting the oscillation signal at any second sensing conductor through which the oscillation signal has passed by means of a capacitive link generated by the method.
Providing an oscillation signal to at least one of the sensing conductors so that the conductive contact body induces a current from each sensing conductor.
Using an oscillation signal to oscillate a detection mechanism with the sensing conductor, wherein the oscillated detection mechanism is simultaneously isolated from a common ground.
Using an oscillation signal to oscillate a first portion of the detection mechanism, the first portion comprising at least a portion of the sensing conductor;
Separating the first portion from the second portion; And
Using a second portion separated to deliver a touch detection output to an external device.
Providing a sensor comprising a patterned arrangement of sense conductors;
Detecting a signal at the sensing conductor; providing a position detection of a first kind of interaction with a position detection of a second kind of interaction, the method comprising:
Detection of a signal resulting from the position detection of said first kind of interaction and said second kind of interaction is performed in the same sensing conductor.
Said position detection of a first kind interaction comprises electromagnetic-based object detection of an object capable of generating an electromagnetic signal.
Said location detection of said second kind of interaction comprises capacitive-based contact detection.
Said position detection of said first kind of interaction comprises electromagnetic detection of an object capable of generating an electromagnetic field, and said position detection of said second kind of interaction comprises capacitive-based contact detection. Position detection method.
A method of manufacturing a contact detector for an electronic display screen,
Disposing a transparent foil on the electronic display screen,
Providing a detection circuit for detecting a capacitive effect on the conductor, and
And applying an excitation device about the electronic screen to excite the electromagnetic stylus to enable the position of the stylus to be detectable in the grid of the transparent conductor.
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