Sensor control circuit, sensor device, and position input method

Abstract

The present invention relates to a sensor control circuit, a sensor device, and a position input method. The sensor control circuit (36) includes: a position detection unit 40 for performing detection processing on a signal distribution output from a planar sensor (32) and acquiring pointing information relating to the position and orientation of a position indicator (12); and an output processing unit 50 for outputting touch information relating to one or a plurality of touch positions corresponding to the position and orientation together with the pointing information acquired through the position detection unit 40 or separately from the pointing information while a specific operation by a user is received.

Description

Sensor control circuit, sensor device, and position input method

[0001] The present invention relates to a sensor control circuit, a sensor device, and a position input method.

[0002] Conventionally, a position input system that inputs a position by detecting the position and orientation of a position indicator is known. For detecting the position indicator, for example, a planar sensor using an electromagnetic induction method or a capacitance method is used.

[0003] Japanese Patent No. 7079838 discloses a position detection device that selectively performs position detection by electromagnetic induction or electrostatic coupling by switching the connection state of loop electrodes with respect to a position detection sensor formed by arranging a plurality of loop electrodes in a planar shape.

[0004] Japanese Patent No. 7079838

[0005] However, in the position detection device disclosed in Japanese Patent No. 7079838, the circuit configuration for switching the connection state of the loop electrodes becomes complicated.

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a sensor control circuit, a sensor device, and a position input method that can switch the position input mode by a position indicator while having a simpler circuit configuration.

[0007] The sensor control circuit in the present invention is a circuit connected to at least a planar sensor for detecting a position indicator, performs a detection process on a signal distribution output from the planar sensor, and obtains pointing information regarding the position and orientation of the position indicator. A position detection unit, and while receiving a specific operation by a user, in combination with the pointing information obtained through the position detection unit or separately from the pointing information, an output processing unit that outputs touch information regarding one or more touch positions corresponding to the position and orientation.

[0008] The sensor device in the present invention comprises at least a planar sensor for detecting a position indicator, a sensor control circuit connected to the planar sensor and outputting data indicating the detection result of the position indicator, and a processor that performs display control for a display device based on the data supplied from the sensor control circuit, wherein the sensor control circuit performs detection processing on the signal distribution output from the planar sensor, acquires pointing information relating to the position and orientation of the position indicator, and, while accepting a specific operation by the user, outputs touch information relating to one or more touch positions corresponding to the position and orientation to the processor, either together with or separately from the acquired pointing information.

[0009] In the position input method of the present invention, one or more control circuits perform a detection step in which they perform detection processing on the signal distribution output from at least a planar sensor for detecting a position indicator and acquire pointing information relating to the position and orientation of the position indicator, and an output step in which, while accepting a specific operation by a user, they output touch information relating to one or more touch positions corresponding to the position and orientation, either together with or separately from the acquired pointing information.

[0010] According to the present invention, it is possible to switch the input mode of position by a position indicator with a simpler circuit configuration.

[0011] This is an overall configuration diagram of a position input system incorporating a sensor device in one embodiment of the present invention. This is a diagram showing an example of a functional block related to the sensor IC in Figure 2. This is a flowchart relating to the input switching operation of the sensor IC shown in Figures 1 and 2. This is a diagram showing an example of a state quantity indicating the position and orientation of an electronic pen. This is a diagram showing an example of the transition of display modes accompanying the input switching operation. This is a diagram showing an example of a simulated touch operation. This is a detailed flowchart showing an example of the conversion process in step SP18 of Figure 3. This is a diagram showing an example of a method for calculating a coordinate value set. This is a diagram schematically showing the change in the projection point accompanying the tilt movement of the electronic pen. This is a diagram showing a first correction method for the coordinate value set. This is a diagram showing a second correction method for the coordinate value set. This is a diagram showing a third correction method for the coordinate value set. This is an overall configuration diagram of a position input system in another embodiment.

[0012] Embodiments of the present invention will be described below with reference to the attached drawings. To facilitate understanding of the description, the same reference numerals are used for identical components in each drawing whenever possible, and redundant descriptions are omitted. In addition, the word "part" may be replaced with other words such as unit, module, device, or element.

[0013] [Configuration of the Position Input System 10] <Overall Configuration> Figure 1 is an overall configuration diagram of a position input system 10 incorporating a sensor device 14 according to one embodiment of the present invention. This position input system 10 is composed of an electronic pen 12 (corresponding to a "position indicator") and a sensor device 14.

[0014] The electronic pen 12 is an electromagnetic induction (EMR) stylus. The "EMR method" is a method of detecting a signal (hereinafter referred to as the EMR signal) transmitted from the electronic pen 12 via electromagnetic induction through a plurality of detection coils arranged in two dimensions. The electronic pen 12 has a cylindrical housing 16. Inside the housing 16 are a control board 18 and a coil 20 and a pressure sensor 22, which are provided on the pen tip (or chip side), respectively. The control board 18 controls the transmission of the EMR signal via the coil 20. The coil 20 is a communication element for generating and transmitting the EMR signal under the alternating magnetic field generated by the sensor device 14. The pressure sensor 22 is a component for detecting the presence or magnitude of pressure acting on the pen tip. A mechanical switch (hereinafter referred to as the side switch 24) is provided on the side of the housing 16 as an operating element.

[0015] The sensor device 14 is a device capable of detecting at least the indicated position of the electronic pen 12, and does not necessarily have a display function. The user can write pictures or characters within the display area of ​​the display panel 30 by holding the electronic pen 12 in one hand and moving it while pressing the pen tip against the operating surface 26 of the sensor device 14. The operating surface 26 is made of a material with high light transmittance and rigidity (such as glass or acrylic resin). Hereinafter, the area of ​​the planar region of the operating surface 26 in which the electronic pen 12 can be detected will be referred to as the "sensor area 28".

[0016] The sensor device 14 is, for example, a computer owned by the user, and consists of a tablet terminal with or without a display function, a smartphone, a personal computer, etc. Alternatively, the sensor device 14 may be a paper-like device specialized for pen detection. Or, the sensor device 14 may be a device installed inside a building (for example, home appliances, furniture, fixtures, etc.), or a device that constitutes part of a building (for example, a wall, floor, window, column, etc.).

[0017] In the example shown in Figure 1, the sensor device 14 includes a display panel 30 (corresponding to "display device"), an EMR sensor 32 (corresponding to "surface sensor"), a display IC (Integrated Circuit) 34, a sensor IC 36 (corresponding to "sensor control circuit"), and a host processor 38 (corresponding to "processor").

[0018] The display panel 30 is positioned directly below the operating surface 26 and displays various images or videos. The display panel 30 may be, for example, an LED (Light-Emitting Diode) panel, a mini LED panel, a micro LED panel, an organic EL (Electro-Luminescence) panel, electronic paper, or a quantum dot panel.

[0019] The EMR sensor 32 is a planar sensor in which a plurality of loop coils are arranged two-dimensionally. The plurality of loop coils consist of [1] a transmitting coil for generating an alternating magnetic field and [2] a detection coil for receiving and detecting an EMR signal. The EMR sensor 32 may be partially or entirely incorporated into other components that make up the sensor device 14. For example, the transmitting coil of the EMR sensor 32 may be integrally provided on the light source substrate (not shown) of the display panel 30.

[0020] The display IC 34 is an integrated circuit that is electrically connected to the display panel 30 and controls the operation of the display panel 30. The display IC 34 drives the display panel 30 based on display signals supplied from the host processor 38. As a result, various images, including content, annotations, or pointers, are displayed on the display panel 30.

[0021] The sensor IC 36 is an integrated circuit that is electrically connected to the EMR sensor 32 and controls the driving of the EMR sensor 32. The specific functions of the sensor IC 36 are explained in detail in Figure 2.

[0022] The host processor 38 is composed of a processing unit including a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and an MPU (Micro-Processing Unit). The host processor 38 works in cooperation with the display IC 34 and the sensor IC 36 to perform digital ink generation or rendering processing. Here, "digital ink" refers to ink data for representing handwritten content. Examples of digital ink data formats, or so-called "ink description languages," include WILL (Wacom Ink Layer Language), InkML (Ink Markup Language), and ISF (Ink Serialized Format).

[0023] The host processor 38 identifies whether or not a user has performed an input operation and what that operation was, based on the data output periodically or irregularly from the sensor IC 36, and supplies image information corresponding to that input operation to the display IC 34. As a result, an image reflecting the user's input operation is displayed in real time. The types of input operations are classified into "pen operation" using the electronic pen 12 and "touch operation" using the user's finger or stylus.

[0024] In the example shown in Figure 1, since the sensor device 14 does not have a touch sensor, the host processor 38 basically only accepts pen input. In this embodiment, by devising the data output method of the sensor IC 36, the host processor 38 selectively accepts normal pen input (hereinafter referred to as pointing input) and pseudo-touch input (hereinafter referred to as pseudo-touch input) from the electronic pen 12. Examples of pseudo-touch inputs include tapping, long-pressing, sliding, swiping, pinching in, pinching out, turning, or stretching.

[0025] <Functional Block Diagram of Sensor IC 36> Figure 2 shows an example of a functional block related to the sensor IC 36 in Figure 1. The sensor IC 36 is composed of a position detection unit 40, an operation reception unit 42, switches 44 and 46, an information conversion unit 48, and an output processing unit 50.

[0026] The position detection unit 40 detects the position of at least the electronic pen 12 via the EMR sensor 32. Specifically, the position detection unit 40 comprises a signal transmission unit 52, a signal acquisition unit 54, a scan control unit 56, and a detection processing unit 58.

[0027] The signal transmission unit 52 generates a drive signal that shows the waveform of an alternating current and supplies this drive signal to the transmission coil, which is part of the EMR sensor 32. By flowing an alternating current through the transmission coil, an alternating magnetic field is generated around the EMR sensor 32.

[0028] The signal acquisition unit 54 acquires the EMR signal transmitted from the electronic pen 12 via a detection coil that constitutes part of the EMR sensor 32. As a result, a signal value correlated with the intensity of the EMR signal is measured for each detection coil.

[0029] The scan control unit 56 performs a scan operation of the EMR sensor 32 by synchronously controlling the signal transmission unit 52 and the signal acquisition unit 54. Through this scan operation, a two-dimensional distribution of signal values ​​(hereinafter simply referred to as "signal distribution") is acquired periodically or irregularly.

[0030] The detection processing unit 58 performs signal processing (hereinafter referred to as "detection processing") to detect the electronic pen 12 in relation to the signal distribution acquired by the signal acquisition unit 54. This detection processing includes: [1] "threshold processing" which detects the presence or absence of the electronic pen 12 based on the relationship between the signal level at each position shown in the signal distribution and a threshold; [2] "position detection processing" which detects the position of the electronic pen 12 by performing interpolation or approximation calculations on the signal distribution; or [3] "attitude detection processing" which detects the attitude of the electronic pen 12 by performing interpolation or approximation calculations on the signal distribution.

[0031] Through this detection process, information regarding the position and orientation of the electronic pen 12 (hereinafter referred to as pointing information) is acquired. The pointing information includes a state variable indicating the position of the electronic pen 12 (hereinafter referred to as position state variable) and a state variable indicating the orientation of the electronic pen 12 (hereinafter referred to as orientation state variable). An example of a position state variable is the two-axis coordinate value (X, Y coordinate value) of the pen tip or the hover distance (Z coordinate value). Here, "hover distance" means the distance in the height direction between the electronic pen 12 and the reference surface (for example, the operating surface 26). An example of an orientation state variable is the three-axis angle, azimuth angle, tilt angle, roll angle, or pitch angle.

[0032] The operation reception unit 42 uses information regarding a specific operation performed by the user (hereinafter referred to as "operation information") to determine whether or not a specific operation has been received. This "specific operation" is an explicit operation that indicates the user's intention. Examples of specific operations include [1] turning on an operation element provided on the electronic pen 12, [2] turning on an operation element provided on the sensor device 14, or [3] turning on a user control displayed on the display panel 30. The operation element may be a mechanical switch including a push switch or slide switch, or a sensor switch for detecting proximity or contact by the user. Examples of sensor switches include a pressure sensor, strain sensor, capacitive sensor, magnetic sensor, optical sensor, or temperature sensor.

[0033] Switch 44 switches the output destination of pointing information in response to a command from the operation reception unit 42. The input terminal of switch 44 is connected to the output side of the detection processing unit 58. The first output terminal of switch 44 is connected to the first input terminal of switch 46. The second output terminal of switch 44 is connected to the input side of the information conversion unit 48.

[0034] Switch 46 switches the type of information input in response to a command from the operation reception unit 42. The first input terminal of switch 46 is connected to the first output terminal of switch 44. The second input side of switch 46 is connected to the output side of the information conversion unit 48. The output terminal of switch 46 is connected to the input side of the output processing unit 50.

[0035] The information conversion unit 48 performs information processing (hereinafter referred to as "conversion processing") that converts the pointing information calculated by the detection processing unit 58 into information relating to one or more touch positions corresponding to the position and orientation of the electronic pen 12 (hereinafter referred to as "touch information"). Examples of touch information include the presence or absence of touch positions, the number of touches, coordinate values, area, or shape. The above-described conversion processing is performed to convert state quantities indicating the position and orientation of the electronic pen 12 into a set of coordinate values ​​indicating multiple touch positions on the sensor coordinate plane 62 (Figure 4) (hereinafter referred to as "coordinate value set"). This conversion processing includes, for example, [1] setting calculation, [2] projection calculation, or [3] correction calculation.

[0036] The "setting calculation" described above is performed to set one or more feature points corresponding to the state quantities of the electronic pen 12. These feature points may be located on the outer surface, inside, or outside of the electronic pen 12. Examples of feature points include the pen tip of the electronic pen 12, a representative point of the coil 20, or a virtual point on the pen shaft. Furthermore, feature points may be determined by their relative positional relationship with other feature points.

[0037] The "projection calculation" described above is performed to calculate a set of coordinate values ​​of projected points (hereinafter referred to as the "first coordinate value set") obtained by projecting one or more feature points set through the setting calculation onto the sensor coordinate plane 62 (Figure 4). If the X and Y coordinate values ​​of the feature points are known, the coordinate values ​​of the projected points are equal to those known coordinate values. If the X and Y coordinate values ​​of the feature points are unknown, the coordinate values ​​of the projected points are calculated based on the relative positional relationship between them and feature points whose X and Y coordinate values ​​are known.

[0038] The "correction calculation" described above is performed to correct the coordinate value set calculated through the projection calculation (i.e., the first coordinate value set) according to the correction rules. Hereinafter, the corrected coordinate value set may be referred to as the "second coordinate value set". This correction calculation is performed as needed. For example, the information conversion unit 48 checks whether the judgment conditions specified from the correction information (hereinafter referred to as correction information) are met, and performs the correction calculation if the judgment conditions are met. Examples of judgment conditions include: [Condition 1] the judgment value exceeds the threshold, [Condition 2] the judgment value falls below the threshold, [Condition 3] the time change of the judgment value exceeds the threshold, [Condition 4] the time change of the judgment value falls below the threshold, or [Condition 5] a combination of conditions 1 to 4. The judgment value may be the value of the state quantity or the coordinate value set itself, or it may be a value calculated from the state quantity or the coordinate value set.

[0039] Examples of the correction information mentioned above include [1] judgment information for determining whether correction is necessary, or [2] correction amount information for determining the amount of correction. Examples of judgment information include, in addition to the current state quantity, [1] history of coordinate value sets calculated in the past, or [2] presence or absence and amount of pen pressure acting on the electronic pen 12. Examples of correction amount information include, in addition to the current state quantity and the current coordinate value set, [1] history of state quantities calculated in the past, [2] history of coordinate value sets calculated in the past, [3] presence or absence and amount of pen pressure acting on the electronic pen 12, or [4] reception strength of the EMR signal (or hover distance estimated from the reception strength).

[0040] The correction rules described above are established to ensure that simulated touch operations are smoother before and after correction. Specifically, examples of correction rules include: [1] that a touch position matching the user's intent is entered, and [2] that a touch operation matching the user's intent (e.g., single-touch operation or multi-touch operation) is performed.

[0041] As a first example, a correction rule is defined such that the distance between the first projection point and the second projection point increases along the relative movement direction between the first projection point and the second projection point. This correction includes [1] a mode of moving the second projection point away while fixing the first projection point, [2] a mode of moving the first projection point away while fixing the second projection point, or [3] a mode of moving both the first projection point and the second projection point away.

[0042] As a second example, a correction rule is defined such that the distance between the first projection point and the second projection point decreases along the relative movement direction between the first projection point and the second projection point. This correction includes [1] a mode of moving the second projection point closer while fixing the first projection point, [2] a mode of moving the first projection point closer while fixing the second projection point, or [3] a mode of moving both the first projection point and the second projection point closer.

[0043] As a third example, a correction rule is defined such that the second projection point exists on a circular orbit centered on the first projection point. Specifically, when the distance between the first projection point on the chip side and the second projection point on the tail side is less than or equal to a threshold value and the roll angle is changing, the position of the second projection point may be moved onto a circular orbit centered on the first projection point. This correction includes [1] a mode of moving the second projection point onto the circular orbit while fixing the first projection point, [2] a mode of moving the first projection point to the center of the circular orbit while fixing the second projection point, or [3] a mode of moving both the first projection point and the second projection point.

[0044] Also, in the above-described correction operation, the coordinate value set may be corrected according to different correction rules depending on whether the electronic pen 12 is in a contact state or a hover state (or a non-contact state). Further, when the electronic pen 12 is in a hover state, the coordinate value set may be corrected using different correction amounts according to the hover distance. Specifically, it may be set such that the correction amount increases as the hover distance of the electronic pen 12 increases and the correction amount decreases as the hover distance of the electronic pen 12 decreases. Alternatively, when the electronic pen 12 is in a contact state, the correction amount may be set to be larger than when it is in a hover state.

[0045] After generating position information including the pointing information or touch information supplied from the switch 46, the output processing unit 50 outputs data including the position information to the host processor 38 (FIG. 1). The output processing unit 50 may output data at a predetermined cycle (for example, 120 Hz). In addition to the above-described position information, this data may include [1] information provided from the electronic pen 12 (for example, pen ID (identification), pen pressure amount, on / off information of the side switch 24, etc.) or [2] motion information (for example, speed / acceleration) calculated from the position information.

[0046] [Operation of the Position Input System 10] The position input system 10 incorporating the sensor device 14 in this embodiment is configured as described above. Subsequently, the position input operation by the sensor device 14 will be described while referring to FIGS. 3 to 12.

[0047] <Basic Operation> FIG. 3 is a flowchart regarding the input switching operation of the sensor IC 36 shown in FIGS. 1 and 2. This input switching operation means an operation of switching between [1] a "pointing operation" accepted as a normal pen operation and [2] a "pseudo touch operation" accepted as a pseudo touch operation.

[0048] In step SP10 of FIG. 3, the position detection unit 40 of the sensor IC 36 checks whether the output timing of data has arrived. If the output timing has not yet arrived (step SP10: NO), the sensor IC 36 stays at step SP10 until the output timing arrives. Thereafter, when the output timing arrives (step SP10: YES), the sensor IC 36 proceeds to the next step SP12.

[0049] In step SP12, the position detection unit 40 (more specifically, the scan control unit 56) performs synchronous control on the signal transmission unit 52 and the signal acquisition unit 54, and executes a scan operation on the EMR sensor 32. Thereby, the signal acquisition unit 54 acquires the two-dimensional distribution (that is, the signal distribution) of the EMR signal output from the EMR sensor 32.

[0050] In step SP14, the position detection unit 40 (more specifically, the detection processing unit 58) performs detection processing on the signal distribution acquired in step SP12. This calculates pointing information indicating the position and orientation of the electronic pen 12.

[0051] In step SP16, the operation reception unit 42 of the sensor IC 36 checks whether a specific operation (for example, pressing the side switch 24) is continuing. If the specific operation is continuing (step SP16: YES), the operation reception unit 42 switches switches 44 and 46 so that pointing information is supplied to the information conversion unit 48, and proceeds to the next step SP18. If the specific operation is not continuing (step SP16: NO), the operation reception unit 42 switches switches 44 and 46 so that pointing information is not supplied to the information conversion unit 48, and proceeds to step SP20, omitting the execution of step SP18 described above.

[0052] In step SP18, the information conversion unit 48 of the sensor IC 36 performs a conversion process on the pointing information calculated in step SP14. This calculates touch information corresponding to the position and orientation of the electronic pen 12.

[0053] In step SP20, the output processing unit 50 outputs data including pointing information or touch information calculated in steps SP14 and SP18 to the host processor 38 (Figure 1). Subsequently, the sensor IC 36 returns to step SP10 and executes steps SP10 to SP20 sequentially. The host processor 38 identifies whether or not a user has performed an input operation and what that operation was, from the data sequentially supplied from the sensor IC 36, and supplies image information corresponding to that input operation to the display IC 34. As a result, an image reflecting the user's input operation is displayed in real time.

[0054] Figure 4 shows an example of a state variable indicating the position and orientation of the electronic pen 12. The position and orientation of the electronic pen 12 are represented on a three-dimensional coordinate space 60 consisting of the X, Y, and Z axes. The three-dimensional coordinate space 60 is defined by the sensor area 28 of the sensor device 14 (Figure 1). Specifically, the plane formed by the sensor area 28 is defined as the X-Y axis plane, and the normal direction of the sensor area 28 is defined as the Z axis. Hereinafter, the above-mentioned X-Y axis plane will also be referred to as the "sensor coordinate plane 62".

[0055] The position and orientation of the electronic pen 12 can be described, for example, by four state variables (X0, Y0, α, β). (X0, Y0) are the X and Y coordinate values ​​indicating the projected position of the feature point P1 of the electronic pen 12 (for example, the pen tip). (α, β) are the tilt angle and azimuth angle of the electronic pen 12. α = 0° when the electronic pen 12 is perpendicular to the sensor coordinate plane 62, and α = 90° when the electronic pen 12 is horizontal to the sensor coordinate plane 62. β = 0° and 180° when the electronic pen 12 is parallel to the X-axis, and β = 90° and 270° when the electronic pen 12 is parallel to the Y-axis.

[0056] Figure 5 shows an example of the transition in display modes accompanying the input switching operation. More specifically, Figure 5 shows an example of pointers 64, 66, and 68 displayed on the display panel 30 of the sensor device 14. While the sensor device 14 is accepting a "pointing operation," a cross-shaped pointer 64 is displayed at the projection position corresponding to the tip of the electronic pen 12 (more specifically, the coil 20). While the sensor device 14 is accepting a "pseudo-touch operation," circular pointers 66 and 68 are simultaneously displayed at two projection positions corresponding to two feature points on the electronic pen 12. The user can confirm the type of input operation by identifying the type or number of pointers 64, 66, and 68.

[0057] Thus, the display IC 34 or host processor 38 (Figure 1) performs display control to display the pointers 64, 66, and 68 in different display modes depending on whether the electronic pen 12 is in the indicated position or the touch position. Examples of display modes include [1] brightness, saturation, and hue, [2] size and shape, [3] presence or absence of outlines, or [4] flashing visual effects.

[0058] Figure 6 shows an example of simulated touch operation. When the user tilts the electronic pen 12 that they are holding, the projection positions of two points on the electronic pen 12 change. In accordance with this displacement, the two pointers 66 and 68 move apart from each other. When this happens, the host processor 38 (Figure 1) accepts a "pinch-out" operation, which is the operation of separating two fingers, and performs display control via the display IC 34 (Figure 1) to enlarge the displayed image. As a result, the user can perform simulated touch operation using the sensor device 14, which does not have a touch sensor implemented.

[0059] <Details of the Conversion Process> Next, an example of the conversion process in step SP18 of Figure 3 will be explained in detail with reference to the detailed flowchart in Figure 7 and Figures 8 to 9.

[0060] In step SP30 of Figure 7, the information conversion unit 48 of the sensor IC 36 acquires the state quantity of the electronic pen 12 included in the pointing information from the detection processing unit 58.

[0061] In step SP32, the information conversion unit 48 sets multiple feature points on the electronic pen 12 based on the state quantities acquired in step SP30.

[0062] In step SP34, the information conversion unit 48 calculates a set of coordinate values ​​corresponding to the multiple feature points set in step SP32 (i.e., a first coordinate value set).

[0063] Figure 8 shows an example of a method for calculating the coordinate value set. The definitions of the three-dimensional coordinate space 60 and the sensor coordinate plane 62 are the same as in Figure 4, so the explanation of these definitions is omitted. In the example in Figure 8, two feature points P1 and P2 are set on the pen axis of the electronic pen 12. Feature point P1 corresponds to a representative point at the position of the coil 20 in Figure 1. Feature point P2 corresponds to a point located at a distance (distance L1) from feature point P1 toward the rear end.

[0064] The projection points R1 and R2 correspond to the positions obtained by projecting the feature points P1 and P2 of the electronic pen 12 onto the sensor coordinate plane 62. The coordinate values ​​of the projection points R1 and R2 are calculated using four state variables (X0, Y0, α, β) as follows: R1 (X0, Y0) R2 (X0 + L1・sinα・cosβ, Y0 + L1・sinα・sinβ)

[0065] In step SP36 of Figure 7, the information conversion unit 48 acquires information (i.e., correction information) for determining whether correction is necessary and the amount of correction for the first coordinate value set calculated in step SP34.

[0066] In step SP38, the information conversion unit 48 refers to the correction information obtained in step SP36 and determines whether correction is necessary for the first coordinate value set. If correction is necessary (step SP38: YES), the information conversion unit 48 proceeds to the next step SP40. If correction is not necessary (step SP38: NO), the information conversion unit 48 skips the execution of step SP40 and proceeds to step SP42.

[0067] In step SP40, the information conversion unit 48 corrects part or all of the first coordinate value set calculated in step SP34. This correction yields a second coordinate value set.

[0068] In step SP42, the information conversion unit 48 selects either the first coordinate value set or the second coordinate value set obtained in step SP34 or step SP40, and determines information regarding one or more touch positions (i.e., touch information).

[0069] In this way, the information conversion unit 48 calculates touch information from pointing information through the conversion process (step SP18 in Figures 3 and 7).

[0070] Figure 9 schematically shows the time change of projection points R1 to R4 as the electronic pen 12 is tilted. In the example in Figure 9, the X-Z plane is shown as viewed toward the Y axis of the three-dimensional coordinate space 60. Before tilting, feature points on the electronic pen 12 are denoted as P1 and P2, and the corresponding projection points are denoted as R1 and R2. As the electronic pen 12 is tilted, feature points P1 and P2 are displaced to feature points Q1 and Q2, respectively, along the movement directions M1 and M2. After tilting, the projection points corresponding to feature points Q1 and Q2 are denoted as R3 and R4.

[0071] In other words, through simulated touch operations, changes in the first touch position (R1→R3) and changes in the second touch position (R2→R4) are detected, and the host processor 38 (Figure 1) interprets this as a pinch-out operation as illustrated in Figure 6, and performs information processing corresponding to the pinch-out operation.

[0072] <Specific Examples of Correction> Next, we will explain specific examples of the correction of the coordinate value set (step SP40 in Figure 7) with reference to Figures 10 to 12.

[0073] Figure 10 shows a first correction method for the coordinate value set. In the example in Figure 10, we assume that the electronic pen 12 is in a hover state with the tip side tilted along the M3 direction while the tail side is fixed. Before tilting, the feature points on the electronic pen 12 are P1 and P2, and the corresponding projection points are R1 and R2. As the electronic pen 12 tilts, feature point P1 is displaced to feature point Q1 along the movement direction M3. After tilting, the projection points corresponding to feature points Q1 and Q2 are R3 and R4.

[0074] Here, feature points P1, P2, and Q2 are in approximately the same position regardless of whether the tilt movement is performed or not. That is, projection points R1, R2, and R4 are located directly below feature point P1, and projection point R3 is located directly below feature point Q1. However, when the electronic pen 12 is in the hover state, the position indicated by the electronic pen 12 appears to be shifted from the position of projection point R3 when using the positions of feature points P1 and Q1, which are the rotation centers of the tilt movement, as a reference, so the user may feel a sense of incongruity.

[0075] Therefore, the information conversion unit 48 (Figure 2) corrects the position of one of the four projection points R1 to R4, namely projection point R3. Through this correction, projection point R3 is shifted by ΔX1 (positive value) in the direction away from projection point R4. The corrected projection point R3' lies on the straight line connecting the two points R3 and R4. In this way, by making the indicated position of the electronic pen 12 approximately coincide with the position of projection point R3', a pseudo-touch operation that matches the user's senses can be realized.

[0076] Figure 11 shows a second method for correcting the coordinate value set. In the example in Figure 11, we assume that the electronic pen 12 is in a downward-facing contact state, and the tail side is tilted along the M4 direction while the tip side is fixed. Before tilting, the feature points on the electronic pen 12 are P1 and P2, and the corresponding projection points are R1 and R2. As the electronic pen 12 tilts, the feature point P2 is displaced to the feature point Q2 along the direction of movement M4. After tilting, the projection points corresponding to the feature points Q1 and Q2 are R3 and R4.

[0077] Here, feature points P1, Q1, and P2 are in approximately the same position regardless of whether the tilt movement is performed or not. That is, projection points R1, R2, and R3 are located directly below feature point P1, and projection point R4 is located directly below feature point Q2. However, when the electronic pen 12 is in contact, the amount of movement from feature point P2 to Q2 tends to be relatively smaller compared to when it is in hover mode. One example of the reason for this is that [1] when the tail side is tilted, the load received from the electronic pen 12 becomes relatively larger, or [2] the tip side of the electronic pen 12 is fixed to the operating surface 26, making it difficult to move the electronic pen 12.

[0078] Therefore, the information conversion unit 48 (Figure 2) corrects the position of one of the four projection points R1 to R4, specifically projection point R4. Through this correction, projection point R4 shifts by ΔX2 (positive value) in the direction away from projection point R3. The corrected projection point R4' lies on the straight line connecting the two points R3 and R4. In this way, by increasing the displacement of the projection point (R2 → R4'), a similar pseudo-touch operation can be achieved regardless of the contact state of the electronic pen 12.

[0079] Figure 12 shows a third method for correcting the coordinate value set. In the example in Figure 12, we assume that the electronic pen 12 is rolled counterclockwise while maintaining a hover state with the pen pointed downwards. Before the roll movement, the feature points on the electronic pen 12 are P1 and P2, and the corresponding projection points are R1 and R2. As the electronic pen 12 is rolled, the feature points P1 and P2 are displaced to feature points Q1 and Q2, respectively, along the direction of movement M5. After the roll movement, the projection points corresponding to feature points Q1 and Q2 are R3 and R4.

[0080] Here, feature points P1, Q1, P2, and Q2 are in approximately the same position regardless of whether the roll movement is performed or not. In other words, projection points R1 to R4 tend not to move regardless of the roll movement. The reason for this is that feature points P1 and P2 are set on the pen axis, which is the center of rotation.

[0081] Therefore, the information conversion unit 48 (Figure 2) corrects the positions of two of the four projection points R1 to R4, R2 and R4. Through this correction, projection point R2 is shifted by L2 (positive value) away from projection point R1 in the direction of the roll angle. Projection point R4 is shifted by L2 away from projection point R3 in the direction of the roll angle. The corrected projection points R2' and R4' are on a circular orbit 70 with radius L2 centered on projection points R1 and R3. In this way, by moving multiple projection points in a distinguishable manner (R2 → R2' and R4 → R4'), a turn operation can be realized through a pseudo-touch operation.

[0082] [Summary of Embodiments] As described above, the sensor device 14 in this embodiment comprises a planar sensor (here, an EMR sensor 32) for detecting a position indicator (here, an electronic pen 12), a sensor control circuit (here, a sensor IC 36) connected to the EMR sensor 32 and outputting data indicating the detection result of the electronic pen 12, and a processor (here, a host processor 38 or a display IC 34) that performs display control for a display device (here, a display panel 30) based on the data supplied from the sensor IC 36.

[0083] Furthermore, the sensor control circuit in this embodiment (here, sensor IC 36) includes a position detection unit 40 that performs detection processing on the signal distribution output from the EMR sensor 32 and acquires pointing information relating to the position and orientation of the electronic pen 12, and an output processing unit 50 that, while accepting a specific operation from the user, outputs touch information relating to one or more touch positions corresponding to the position and orientation, either together with or separately from the pointing information acquired through the position detection unit 40.

[0084] Furthermore, in the position input method of this embodiment, one or more control circuits (here, sensor IC 36) perform detection processing on the signal distribution output from the EMR sensor 32 and perform a detection step (SP 14) to acquire pointing information relating to the position and orientation of the electronic pen 12, and an output step (step SP 20) which, while accepting a specific operation from the user, outputs touch information relating to one or more touch positions corresponding to the position and orientation, either together with or separately from the acquired pointing information.

[0085] In this way, while accepting a specific operation from the user, touch information is output either together with or separately from the acquired pointing information. Therefore, even with a simpler circuit configuration, it is possible to switch the input method of the position by the electronic pen 12, that is, between pointing operation and pseudo-touch operation.

[0086] This operation switching makes it possible to achieve touch input functionality equivalent to that of using the user's finger, using only the electronic pen 12, thereby improving convenience for the user. In particular, even if a surface sensor (in this case, an EMR sensor 32) that cannot detect user touch is implemented in the sensor device 14, it is possible to achieve touch input functionality as if using a finger.

[0087] Furthermore, the pointing information may include state quantities indicating the position and orientation of the electronic pen 12, and the touch information may include a set of coordinate values ​​indicating multiple touch positions on the sensor coordinate plane 62 formed by the EMR sensor 32. In this case, the information conversion unit 48 may perform a conversion process to convert the above-mentioned state quantities into a set of coordinate values.

[0088] Furthermore, the conversion process may include: [1] a setting operation to set multiple feature points P1 and P2 corresponding to state variables; and [2] a projection operation to calculate a set of coordinate values ​​corresponding to projected points R1 and R2 formed by projecting the set multiple feature points P1 and P2 onto the sensor coordinate plane 62. This makes it easier to obtain the set of coordinate values ​​through geometric calculations.

[0089] Furthermore, the conversion process may further include a correction operation that corrects the coordinate value set according to the correction rules. The correction of the coordinate value set makes the pseudo-touch operation smoother.

[0090] For example, if multiple projection points include a first projection point and a second projection point, the correction rule is that the distance between the first projection point and the second projection point becomes longer or shorter along the relative direction of movement between the first projection point and the second projection point. This makes it easier for operations such as pinch-in, pinch-out, or stretch to be performed as intended by the user.

[0091] For example, if multiple projection points include a first projection point and a second projection point, the correction rule is that the second projection point lies on a circular orbit centered on the first projection point. This makes it easier for operations such as turning to be performed as intended by the user.

[0092] Furthermore, in the correction calculation, the coordinate value set may be corrected according to different correction rules depending on whether the electronic pen 12 is in a contact state or a hover state. This allows for correction that takes into account, for example, the difference in ease of movement of the electronic pen 12 depending on whether or not there is a physical constraint on the pen tip.

[0093] Furthermore, in the correction calculation, if the electronic pen 12 is in a hover state, the coordinate value set may be corrected using different correction amounts depending on the hover distance. This allows for correction that takes into account, for example, the fact that the discrepancy between the indicated position and the projected position of the electronic pen 12 increases as the hover distance increases.

[0094] Furthermore, the state variables may include [1] the indicated position, azimuth angle, and tilt angle of the electronic pen 12, or [2] the indicated position and roll angle of the electronic pen 12. This makes it possible to identify multiple projection points R1 and R2 corresponding to the position and orientation of the electronic pen 12.

[0095] Furthermore, a specific operation may involve turning on an operating element (in this case, the side switch 24) provided on the electronic pen 12. This prevents the input operation from being switched unintentionally by the user.

[0096] Furthermore, the host processor 38 or the display IC 34 may control the display of the display device (in this case, the display panel 30) to display pointers 64, 66, and 68 in different display modes depending on whether the electronic pen 12 is in the indicated position or the touch position. This allows the user to confirm the type of input operation by identifying the type or number of pointers 64, 66, and 68.

[0097] [Another Embodiment] Figure 13 is an overall configuration diagram of the position input system 100 in another embodiment. This position input system 100 is composed of electronic pens 102a and 102b (corresponding to "position indicators") and a sensor device 104.

[0098] The electronic pens 102a and 102b are styluses that actively generate signals from the electrical energy they store and transmit these signals via one or more pen electrodes using an "active electrostatic coupling (AES) method" or a "capacitive method." The housing 106 of the electronic pen 102a is provided with two pen electrodes (a tip electrode 108 and a ring electrode 110). The housing 106 of the electronic pen 102b is provided with two pen electrodes (a tip electrode 108 and a tail electrode 112). The tip electrode 108, ring electrode 110, and tail electrode 112 are all communication elements for receiving signals from the sensor device 104 (so-called uplink signals) or transmitting signals generated by the electronic pens 102a and 102b (so-called downlink signals).

[0099] The sensor device 104, like the sensor device 14 in Figure 1, is a device capable of detecting the indicated positions of the electronic pens 102a and 102b, and does not require a display function. In the example in Figure 13, the sensor device 104 includes a touch sensor 120 (corresponding to a "surface sensor") and a sensor IC 122 (corresponding to a "sensor control circuit"), in addition to the display panel 30, display IC 34, and host processor 38 (Figure 1).

[0100] The touch sensor 120 is a capacitive position sensor (more specifically, a mutual capacitance type or self-capacitive type) in which multiple sensor electrodes are arranged in a planar manner. The electronic pens 102a, 102b (or the user's finger) and the touch sensor 120 are capacitively coupled to each other by capacitance. Each sensor electrode may be made of a transparent conductive material containing ITO (Indium Tin Oxide), or it may be made of a wire mesh sensor. The touch sensor 120 may be an "internal type" (further classified as an on-cell type or in-cell type) sensor that is integrated with the display panel 30, or it may be an "external type" (or out-cell type) sensor that is attached to the display panel 30 from the outside.

[0101] Sensor IC 122 is a control circuit that performs detection functions for electronic pens 102a and 102b (hereinafter also referred to as "pen detection function") and passive pointer (e.g., user's finger) (hereinafter also referred to as "touch detection function") via touch sensor 120. When performing the pen detection function, sensor IC 122 detects the pen position by electronic pens 102a and 102b by transmitting an uplink signal to electronic pens 102a and 102b and receiving a downlink signal from electronic pens 102a and 102b. When performing the touch detection function, sensor IC 122 detects the touch position by a finger by transmitting a finger detection signal and receiving a finger detection signal accompanied by a change in capacitance as a finger approaches.

[0102] The sensor IC 122 basically has the same functional blocks as in Figure 2. In the case of the electronic pen 102a, the state variables may be the indicated position, azimuth angle, and tilt angle, as in the case of the electronic pen 12, or they may be the indicated position and roll angle. In the case of the electronic pen 102a, the state variables may be multiple projected positions obtained by projecting multiple pen electrodes (here, the tip electrode 108 and the tail electrode 112) onto the sensor coordinate plane 62 (Figure 4).

[0103] As described above, the sensor device 104 in another embodiment includes a planar sensor (here, a touch sensor 120) for detecting position indicators (here, electronic pens 102a, 102b), a sensor control circuit (here, a sensor IC 122) connected to the touch sensor 120 and outputting data indicating the detection result of the electronic pens 102a, 102b, and a processor (here, a host processor 38 or a display IC 34) that performs display control for a display device (here, a display panel 30) based on the data supplied from the sensor IC 122.

[0104] Furthermore, the sensor control circuit in this embodiment (here, sensor IC 122) includes a position detection unit 40 that performs detection processing on the signal distribution output from the touch sensor 120 and acquires pointing information relating to the position and orientation of the electronic pens 102a and 102b, and an output processing unit 50 that, while accepting a specific operation from the user, outputs touch information relating to one or more touch positions corresponding to the position and orientation, either together with or separately from the pointing information acquired through the position detection unit 40.

[0105] Thus, even when the sensor device 104 is equipped with a touch sensor 120, the sensor IC 122, like the sensor IC 36 in Figures 1 and 2, has a simpler circuit configuration while still being able to switch between the input mode of position by the electronic pens 102a and 102b, that is, pointing operation or pseudo-touch operation.

[0106] Furthermore, the state variables may include multiple projection positions obtained by projecting the multiple communication elements of the electronic pens 102a and 102b onto the sensor coordinate plane 62 (Figure 4). This makes it possible to identify multiple projection points R1 and R2 corresponding to the position and orientation of the electronic pens 102a and 102b.

[0107] [Modifications] It should be noted that the present invention is not limited to the following embodiments and modifications, and can be freely modified without departing from the spirit of the invention. Alternatively, each configuration may be arbitrarily combined to the extent that no technical inconsistencies arise. Alternatively, the execution status or execution order of each step constituting the flowchart may be changed to the extent that no technical inconsistencies arise.

[0108] In the embodiments described above, the case in which the indicated position is input using an electronic pen 12 (Figure 1) or electronic pens 102a, 102b (Figure 13) was used as an example, but various types of position indicators, including laser pointers, may be used instead. In the embodiments described above, the case in which the sensor device 14 has a built-in display panel 30 (Figures 1 and 13) was used as an example, but instead, a display device separate from the sensor device 14 may be connected externally.

[0109] In the above-described embodiment, the case in which the sensor IC 36 (Figure 2) selectively outputs pointing information or touch information was given as an example, but instead, both pointing information and touch information may be output. In the above-described embodiment, the case in which the information conversion unit 48 of the sensor IC 36 corrects the touch information (or coordinate value set) was given as an example, but instead, the host processor 38 may correct the touch information supplied from the sensor IC 36.

[0110] [Explanation of Symbols] 10, 100...Position input system, 12, 102a, 102b...Electronic pen (position indicator), 14, 104...Sensor device, 26...Operating surface, 28...Sensor area, 30...Display panel, 32...EMR sensor (surface sensor), 36, 122...Sensor IC (sensor control circuit), 60...Three-dimensional coordinate space, 62...Sensor coordinate plane, 120...Touch sensor (surface sensor), P1-P4, Q1-Q4...Feature points, R1-R4, R2'-R4'...Projection points

Claims

1. A sensor control circuit connected to a planar sensor for detecting at least a position indicator, comprising: a position detection unit that performs detection processing on the signal distribution output from the planar sensor and acquires pointing information relating to the position and orientation of the position indicator; and an output processing unit that, while accepting a specific operation by a user, outputs touch information relating to one or more touch positions corresponding to the position and orientation, either together with or separately from the pointing information acquired through the position detection unit.

2. The sensor control circuit according to claim 1, wherein the pointing information includes a state quantity indicating the position and orientation, the touch information includes a set of coordinate values ​​indicating the plurality of touch positions on the sensor coordinate plane formed by the planar sensor, and the sensor control circuit further comprises an information conversion unit that performs a conversion process to convert the state quantity into the set of coordinate values.

3. The sensor control circuit according to claim 2, wherein the conversion process includes a setting calculation for setting a plurality of feature points corresponding to the state quantity, and a projection calculation for calculating a set of coordinate values ​​corresponding to a plurality of projected points obtained by projecting the set plurality of feature points onto the sensor coordinate plane.

4. The sensor control circuit according to claim 3, wherein the conversion process further includes a correction calculation for correcting the coordinate value set according to a correction rule.

5. The sensor control circuit according to claim 4, wherein the plurality of projection points include a first projection point and a second projection point, and the correction rule is that the distance between the first projection point and the second projection point becomes longer or shorter along the relative movement direction between the first projection point and the second projection point.

6. The sensor control circuit according to claim 4, wherein the plurality of projection points include a first projection point and a second projection point, and the correction rule is that the second projection point lies on a circular orbit centered on the first projection point.

7. The sensor control circuit according to claim 4, wherein the correction rule is the detection of a pinch-in operation, a pinch-out operation, a stretch operation, or a turn operation.

8. The sensor control circuit according to claim 4, wherein the position indicator is an electronic pen, and in the correction calculation, the set of coordinate values ​​is corrected according to different correction rules depending on whether the electronic pen is in a contact state or a hover state.

9. The sensor control circuit according to claim 8, wherein, in the correction calculation, when the electronic pen is in a hover state, the coordinate value set is corrected using different correction amounts depending on the hover distance.

10. The sensor control circuit according to claim 2, wherein the state quantities include the indicated position, azimuth angle, and tilt angle of the position indicator.

11. The sensor control circuit according to claim 2, wherein the state quantities include the indicated position of the position indicator and the roll angle.

12. The sensor control circuit according to claim 2, wherein the state quantity includes a plurality of projected positions obtained by projecting a plurality of communication elements of the position indicator onto the sensor coordinate plane.

13. The sensor control circuit according to claim 1, wherein the specific operation is to turn on an operating element provided on the position indicator.

14. A sensor device comprising: a planar sensor for detecting at least a position indicator; a sensor control circuit connected to the planar sensor and outputting data indicating the detection result of the position indicator; and a processor that performs display control on a display device based on the data supplied from the sensor control circuit, wherein the sensor control circuit performs detection processing on the signal distribution output from the planar sensor, acquires pointing information relating to the position and orientation of the position indicator, and, while accepting a specific operation by a user, outputs touch information relating to one or more touch positions corresponding to the position and orientation to the processor, either together with or separately from the acquired pointing information.

15. The sensor device according to claim 14, wherein the processor performs the display control to display the pointer in different display modes depending on whether it is the indicated position of the position indicator or the touch position.

16. A position input method comprising: a detection step in which one or more control circuits perform detection processing on a signal distribution output from a planar sensor for detecting at least a position indicator and acquire pointing information relating to the position and orientation of the position indicator; and an output step in which, while accepting a specific operation by a user, touch information relating to one or more touch positions corresponding to the position and orientation is output together with or separately from the acquired pointing information.

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