Input device and palm rejection range setting method

Abstract

Provided is an input device that can perform palm rejection even when the state of an input surface of the input device with respect to a user changes.　This input device comprises: a pen indicating position detection unit that detects a pen indicating position on an input surface indicated by an electronic pen held by a user; a touch position detection unit that detects a touch position on the input surface touched by the user; an image capturing unit that is attached to a position where it is possible to image the face of the user holding the electronic pen; and a palm rejection range setting unit that sets a palm rejection range on the input surface on the basis of an inclination of the face of the user detected from the image captured by the image capturing unit and the pen indicating position detected by the pen indicating position detection unit.

Description

Input Device and Palm Rejection Range Setting Method

[0001] The present invention relates to an input device having a touch detection function for detecting a position touched by a finger and a pen instruction detection function for detecting a position indicated by an electronic pen. The present invention also relates to a method for setting a palm rejection range in an input device.

[0002] As shown in FIG. 16, when a user holds the electronic pen 200 with the hand 300H and performs a writing input, when the pen tip 200a of the electronic pen 200 contacts the input surface 210 of the position detection sensor of the input device, the palm 300Ha or the little finger 300Fa of the hand 300H holding the electronic pen 200 may contact the input surface 210. The palm 300Ha or the little finger 300Fa contacting the input surface 210 is called a palm.

[0003] Since this part of the palm is not in contact with the input surface 210 for the user to perform a touch instruction, conventionally, the contact of the palm such as the palm 300Ha or the little finger 300Fa on the input surface 210 is determined not to be an input operation, and a function (referred to as a palm rejection function) that ignores (invalidates) the touch detection is provided (see, for example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2012-221358)).

[0004] The palm rejection function disclosed in this Patent Document 1 registers and stores in advance in the input device the positional relationship between the pen instruction position by the electronic pen and the detection position of the palm when the user holds the electronic pen with the hand and performs an instruction input operation. At the time of an instruction input operation by the electronic pen by an actual user, the input device refers to the registered positional relationship and ignores the detection of the palm when the palm is detected.

[0005] Japanese Patent Application Laid-Open No. 2012-221358

[0006] In order to realize the palm rejection function disclosed in the above-mentioned Patent Document 1, it is necessary to register in advance the positional relationship between the pen instruction position by the electronic pen and the detection position of the palm by the user, which is a relatively troublesome problem.

[0007] Furthermore, the registration of the positional relationship between the pen instruction position using the electronic pen and the palm detection position is generally performed when the user's position relative to the input surface of the input device's position detection sensor is in a specific positional relationship, such as when the user is directly facing the input surface. Typically, the palm is registered at a position below the pen instruction position. If the state of the input surface relative to the user is the same as at the time of registration, and the user makes an instruction input with the electronic pen on the input device, the palm can be easily detected based on the registered information.

[0008] However, the state of the input surface of the input device relative to the user is not always the same as at the time of registration. For example, if a user rotates the input device and makes an instruction input with an electronic pen, the position of the user's palm below the pen's instruction position will not be on the lower edge of the input surface. Therefore, it becomes difficult to accurately detect the palm using a method that relies solely on registration information.

[0009] In view of the above problems, this invention aims to provide an input device that allows the user to perform palm rejection accurately even when the state of the input surface of the input device changes, without requiring the user to perform troublesome operations such as registration.

[0010] To solve the above problems, the present invention provides an input device comprising: a pen instruction position detection unit that detects the pen instruction position on an input surface made by an electronic pen held by the user; a touch position detection unit that detects the user's touch position on the input surface; an imaging unit mounted in a position capable of capturing images of the user's face as they hold the electronic pen; and a palm reject range setting unit that sets a palm reject range on the input surface based on the tilt of the user's face in the image captured by the imaging unit and the pen instruction position detected by the pen instruction position detection unit.

[0011] As mentioned above, the user holds the electronic pen and inputs positional information on the input surface, so the pen's indicated position has a predetermined positional relationship with the palm. Therefore, it is possible to set the palm rejection range based on this pen's indicated position.

[0012] In the input device with the above configuration, the palm rejection range on the input surface is set not only based on the pen position but also on the tilt of the user's face in the image captured by the imaging unit. Palming occurs below the pen position, but the direction below the pen position corresponds to the direction of the face tilt in the captured image. Therefore, with the input device with the above configuration, even if the positional relationship between the user and the input surface of the input device changes, an appropriate palm rejection range corresponding to that change is set.

[0013] This is a diagram illustrating an example of the external configuration of the first embodiment of the input device according to this invention. This is an exploded perspective view illustrating an example of the hardware configuration of the first embodiment of the input device according to this invention. This is a diagram illustrating an example of the electrical configuration of the first embodiment of the input device according to this invention. This is a diagram illustrating an overview of the method for setting the palm reject range in the first embodiment of the input device according to this invention. This is a diagram illustrating an overview of the method for setting the palm reject range in the first embodiment of the input device according to this invention. This is a diagram illustrating an overview of the method for setting the palm reject range in the first embodiment of the input device according to this invention. This is a diagram illustrating an overview of the method for setting the palm reject range in the first embodiment of the input device according to this invention. This is a diagram illustrating an overview of the method for setting the palm reject range in the first embodiment of the input device according to this invention. This is a diagram illustrating a part of a flowchart illustrating an example of the operation of setting the palm reject range in the first embodiment of the input device according to this invention. This is a diagram illustrating a part of a flowchart illustrating an example of the operation of setting the palm reject range in the first embodiment of the input device according to this invention. This is a diagram illustrating a flowchart illustrating an example of the processing operation of the first embodiment of the input device according to this invention. This is a diagram illustrating an example of the electrical configuration of the second embodiment of the input device according to this invention. This is a diagram used to illustrate an example of the processing operation of the second embodiment of the input device according to this invention. This figure is used to illustrate another embodiment of the input device according to this invention. This figure is used to illustrate yet another embodiment of the input device according to this invention. This figure illustrates how palming occurs when pen input is performed using an electronic pen in the input device.

[0014] Hereinafter, embodiments of the input device according to this invention will be described with reference to the figures.

[0015] [First Embodiment] <Example of Hardware Configuration of Input Device of the First Embodiment> Figure 1 shows the external appearance of the input device 1 of the first embodiment of this invention, and Figure 2 is an exploded perspective view of an example of the configuration of the input device 1 of this embodiment.

[0016] As shown in Figure 1, the input device 1 of this embodiment has a thin, rectangular housing 16 with a display screen 11D on one side. The input device 1 of this embodiment uses the entire display area of ​​the display screen 11D as an input surface 11S that accepts input operations from the user, and has the function of detecting the position indicated by the user's finger 2F and the tip 3a of the electronic pen 3 as examples of a position indicator, making it a pad-type information processing terminal.

[0017] In this embodiment, the housing 16 of the input device 1 is equipped with a camera 4, which is an example of an imaging unit for capturing an image of the user's face, in a position that allows for capturing the face of the user holding the electronic pen. In this example, assuming that the input device 1 is used in a horizontal orientation with the user facing the input surface 11S directly, the camera 4 is mounted in the center of the upper edge portion of the housing 16, as shown in Figure 1, in the portion that forms the frame around the display screen 11D.

[0018] The input device 1 in this embodiment includes a touch position detection unit that detects the touch position of the user's finger 2F on the input surface 11S, and a pen instruction position detection unit that detects the pen instruction position of the electronic pen 3 on the input surface 11S. The input device 1 in this embodiment also includes a control unit that performs control processing based on the touch position detected by the touch position detection unit and the pen instruction position detected by the pen instruction position detection unit, and controls the display image to be displayed on the display screen 11D.

[0019] The display device 11 is a flat display such as a liquid crystal display or an organic electroluminescence (EL) display, and as shown in Figure 2, the display substrate 111 has a display screen 11D on which a large number of display pixels 112 are arranged in the X-axis direction (horizontal direction) and a large number of display pixels 112 are arranged in the Y-axis direction (vertical direction) which is perpendicular to the X-axis direction.

[0020] In this embodiment of the input device 1, a touch detection sensor 12 is provided on the front side (surface side) of the display screen 11D of the display device 11 for detecting the touch position of the user's finger 2F on the input surface 11S, and a pen instruction detection sensor 13 is provided on the rear side (back side) of the display screen 11D for detecting the pen instruction position of the electronic pen 3 on the input surface 11S. Furthermore, as shown in Figure 2, a control circuit board 14 on which the control unit is formed is provided on the back side of the pen instruction detection sensor 13.

[0021] Then, as shown in Figure 2, the touch detection sensor 12, the display device 11, the pen instruction detection sensor 13, and the control circuit board 14 are superimposed in a direction perpendicular to the display screen 11D and housed in a recess 161 of a housing 16, which is made of, for example, synthetic resin. Subsequently, the frame area 15a of a rectangular planar member 15 made of, for example, glass or resin, is joined to the rectangular frame area 162 of the housing 16, for example, by adhesive, thereby closing the recess 161 of the housing 16 and assembling the input device 1.

[0022] As mentioned above, in this example, as shown in Figure 2, the camera 4 is mounted on the upper edge of the rectangular frame area 162 of the housing 16, with the shooting direction being perpendicular to the display screen 11D.

[0023] In this embodiment, the left and right sides of the frame region 162 of the housing 16 are provided with handedness notification operation units 5R and 5L for notifying the input device 1 of the user's dominant hand. In this example, the handedness notification operation unit 5R for notifying that the user is right-handed is provided on the right side of the frame region 162 of the housing 16, and the handedness notification operation unit 5L for notifying that the user is left-handed is provided on the left side. In this example, the handedness notification operation units 5R and 5L are operated by push buttons.

[0024] In this example, the input device 1 is provided with handedness indicators 6R and 6L, which are, for example, LEDs, that indicate whether the left or right hand is the dominant hand, corresponding to the handedness notification operation units 5R and 5L. Specifically, when the handedness indicator 6R is lit, the input device 1 has been notified that the dominant hand is the right hand, and when the handedness indicator 6L is lit, the input device 1 has been notified that the dominant hand is the left hand.

[0025] The area enclosed by the dotted line in Figure 2 on the front side of the planar member 15 is the input surface 11S when position is indicated by a finger 2F or the tip 3a of the electronic pen 3. On the back side of this planar member 15, the touch detection sensor 12, the display device 11, the pen instruction detection sensor 13, and the control circuit board 14 are arranged.

[0026] In this embodiment, the touch detection sensor 12 is an electrostatic coupling type position detection sensor and, together with the touch position detection circuit provided on the control circuit board 14, constitutes a touch position detection unit. In this embodiment, the pen instruction detection sensor 13 is an electromagnetic induction type position detection sensor and, together with the pen instruction position detection circuit provided on the control circuit board 14, constitutes a pen instruction position detection unit.

[0027] In this embodiment, the touch position detection area of ​​the touch detection sensor 12, the pen instruction position detection area of ​​the pen instruction detection sensor 13, and the display area of ​​the display screen 11D of the display device 11 are approximately the same size and are arranged to overlap in a direction perpendicular to the display screen 11D (input surface 11S).

[0028] <Example of Electrical Configuration of Input Device 1> Figure 3 shows an example of the electrical configuration of the input device 1 of this embodiment, which has the hardware configuration described above. In addition, Figure 3 also shows an example of the electrical configuration of the electronic pen 3, and the signal interaction between the electronic pen 3 and the input device 1 will also be explained.

[0029] As shown in Figure 3, the input device 1 of this embodiment is configured such that, as described above, a display device 11, a touch detection sensor 12, and a pen instruction detection sensor 13 are connected to a control unit 100 provided on a control circuit board 14.

[0030] The control unit 100 is configured by connecting a display control circuit 101, a touch position detection circuit 102, and a pen instruction position detection circuit 103 to a processing control circuit 104. In this embodiment, the processing control circuit 104 is composed of a computer (microprocessor) and has the function of controlling the overall operation of the input device 1 in this embodiment.

[0031] The display device 11 is connected to the display control circuit 101. The touch detection sensor 12 is connected to the touch position detection circuit 102, and the pen instruction detection sensor 13 is connected to the pen instruction position detection circuit 103.

[0032] Although not shown in Figure 2, the touch position detection circuit 102 and touch detection sensor 12, the pen instruction position detection circuit 103 and pen instruction detection sensor 13, and the display control circuit 101 and display device 11 of the control unit 100 on the control circuit board 14 are electrically connected, for example, by flexible cables. Similarly, although not shown in Figure 2, the camera 4, the dominant hand notification operation units 5R and 5L, and the dominant hand indicators 6R and 6L are also connected to the processing control circuit 104 of the control unit 100 on the control circuit board 14. The captured image signal from the camera 4 is supplied to the processing control circuit 104 of the control unit 100 via the amplifier 105.

[0033] In this example, the touch detection sensor 12 consists of a plurality of linear X conductors 12X1 to 12Xn (n = 1, 2, ...) arranged in the X-axis direction (e.g., horizontal direction) on one surface of the insulating substrate, and a plurality of linear Y conductors 12Y1 to 12Ym (m = 1, 2, ...) arranged in the Y-axis direction (e.g., vertical direction) on the other surface of the insulating substrate, intersecting the plurality of X conductors 12X1 to 12Xn at a right angle. The X conductors 12X1 to 12Xn and the Y conductors 12Y1 to 12Ym are capacitively coupled at their intersection points via the insulating substrate.

[0034] The touch position detection circuit 102 includes a transmitting circuit and a receiving circuit for transmitting a signal to detect the touch of finger 2F. The transmitting circuit of the touch position detection circuit is connected to, for example, the Y conductors 12Y1 to 12Ym of the touch detection sensor 12, and the receiving circuit is connected to the X conductors 12X1 to 12Xn of the touch detection sensor 12. For example, a spreading code can be used as the transmitting signal to detect the touch of finger 2F.

[0035] The transmission signal sent from the transmission circuit of the touch position detection circuit to the Y conductors 12Y1 to 12Ym of the touch detection sensor 12 is received by the receiving circuit of the touch position detection circuit via the capacitance between the Y conductors 12Y1 to 12Ym and the X conductors 12X1 to 12Xn of the touch detection sensor 12, and via the X conductors 12X1 to 12Xn.

[0036] In this case, at the location where the finger 2F is touching the touch detection sensor 12, a portion of the transmitted signal flows through the human body, causing the level of the received signal detected by the receiving circuit at that touch location to decrease. The touch position detection circuit 102 detects the location on the touch detection sensor 12 where the level of the received signal is low by monitoring the correlation between the transmitted signal and the received signal. In this case, the touch position detection circuit 102 can simultaneously detect multiple fingers touching at multiple different locations on the input surface 11S. The touch position detection circuit 102 then supplies the detected touch position information to the processing control circuit 104.

[0037] Next, as shown in Figure 3, the pen instruction detection sensor 13 is configured with multiple X-axis loop coils 13X and multiple Y-axis loop coils 13Y arranged in the X-axis and Y-axis directions, respectively. This pen instruction detection sensor 13 is positioned on the back side of the display screen 11D of the display device 11, superimposed on the display device 11 and the touch detection sensor 12, in order to detect the position indicated by the electronic pen 3 on the input surface 11S. Therefore, both the touch detection sensor 12 and the pen instruction detection sensor 13 are arranged to be able to detect the coordinate position on the input surface 11S.

[0038] As shown in Figure 3, the electromagnetically coupled electronic pen 3 in this example includes a resonant circuit RCp consisting of a coil 31 and a capacitor 32. The electronic pen 3 in this example also includes a pressure detection unit that detects the pressure applied to the pen tip 3a of its core as a change in capacitance, and a variable capacitance capacitor 33C, which is part of the pressure detection unit, is connected in parallel to the coil 31 so as to form part of the resonant circuit RCp.

[0039] Then, the pen position detection circuit 103 transmits an AC signal with a frequency equal to the resonant frequency of the resonant circuit RCp of the electronic pen 3 to the electronic pen 3 through the loop coils 13X and 13Y of the pen position detection sensor 13. In the electronic pen 3, the resonant circuit RCp receives the AC signal from the pen position detection sensor 13 through electromagnetic induction coupling with the loop coils 13X and 13Y of the pen position detection sensor 13, and the received AC signal is fed back from the resonant circuit RCp to the pen position detection sensor 13.

[0040] The pen position detection circuit 103 receives a feedback signal from the electronic pen 3 through the pen position detection sensor 13, and detects the positions of the loop coils 13X and 13Y of the pen position detection sensor 13 that detect the received AC signal, thereby detecting the position indicated by the pen tip 3a of the core body of the electronic pen 3.

[0041] In this case, in the electronic pen 3, the capacitance of the variable capacitance capacitor 33C that constitutes the pressure detection unit changes according to the pressure applied to the pen tip 3a of the pen body. As a result, the frequency of the AC signal fed back from the resonant circuit RCp of the electronic pen 3 to the pen instruction detection sensor 13 changes according to the capacitance of the variable capacitance capacitor 33C. The pen instruction position detection circuit 103 detects the pressure applied to the pen tip of the pen body of the electronic pen 3 by synchronously detecting the received AC signal with a signal of the transmission frequency and detecting the change in the wavenumber (phase change) of the AC signal. The pen instruction position detection circuit 103 then supplies the coordinate information of the detected pen instruction position, along with the detected pressure information, to the processing control circuit 104.

[0042] The processing control circuit 104 also detects whether the tip 3a of the electronic pen 3 is in contact with the input surface 11S or is in a non-contact state above the input surface 11S (referred to as a hover state) based on the pen pressure information from the pen instruction position detection circuit 103, and includes the contact state detection information of the detection result in the pen instruction position information detected by the pen instruction position detection circuit 103. In other words, in this embodiment, the pen instruction position detection circuit 103 can detect not only the coordinate information of the position when the tip 3a of the electronic pen 3 is in contact with the input surface 11S, but also the coordinate information of the position of the tip 3a of the electronic pen 3 when it is in a hover state.

[0043] Furthermore, the processing control circuit 104 performs processing similar to that of a well-known input device, based on the touch position of the finger 2F detected by the touch position detection circuit 102 and the pen instruction position detected by the pen instruction position detection circuit 103. In this embodiment, the palm rejection range is set from the pen instruction position, the image captured by the camera 4, and the operation information of the dominant hand notification operation units 5R and 5L, and the palm rejection process is executed using the set palm rejection range.

[0044] As a process similar to that of a well-known input device, the processing control circuit 104 generates an image of a writing locus based on the pen instruction position by the electronic pen 3 and supplies it to the display device 11 through the display control circuit 101, thereby displaying the writing locus on the display screen 11D, or determines an application program corresponding to an icon displayed at a position touched by the pen tip 3a or the finger 2F of the electronic pen 3 and starts the application program.

[0045] <Explanation of setting the palm rejection range in the first embodiment> An outline of a method for setting the palm rejection range in the input device 1 of the first embodiment will be described.

[0046] Normally, as shown in FIG. 4(A), the user holds the electronic pen 3 and makes a position instruction input or a touch input on the input surface 11S while facing the input surface 11S of the input device 1 (while directly viewing the display screen 11D). Then, normally, in a state where the plane direction (hereinafter referred to as the lateral direction of the chest plate) DRa orthogonal to the height direction of the user's chest plate and the plane direction (hereinafter referred to as the lateral direction of the input surface 11S) DRb along the upper side where the camera 4 of the frame region 162 of the input surface 11S is installed coincide, the user makes a pen instruction input.

[0047] In the above state, for example, when a right-handed user holds the electronic pen 3 with the right hand and makes a position instruction on the input surface 11S of the input device 1 and makes a touch input with the left hand, generally, the state of the right hand holding the electronic pen 3 on the input surface 11S is as shown in FIG. 4(A).

[0048] That is, as shown in FIG. 4(A), the palm such as the little finger or palm of a right-handed user is located on the right side of a line parallel to the vertical direction of the input surface 11S and including the pen instruction position Po by the electronic pen 3. Therefore, in the case of a right-handed user, it is possible to set the filled area on the right side (the right side portion of the frame region 162) as the palm rejection range with a line parallel to the vertical direction of the input surface 11S including the pen instruction position Po as the boundary line BL.

[0049] Although not shown in the diagram, for example, if a left-handed user holds the electronic pen 3 with their left hand to indicate a position on the input surface 11S of the input device 1, and also performs touch input with their right hand, the palm of the user's left hand, such as the little finger or palm, will be located to the left of a line parallel to the vertical direction of the input surface 11S, which includes the pen indication position Po made by the electronic pen 3. Therefore, in the case of a left-handed user, it is possible to set the boundary line BL, which includes the pen indication position Po and is parallel to the vertical direction of the input surface 11S, as the boundary line, and the filled area to the left of this line (the left edge of the frame area 162) as the palm rejection area.

[0050] Furthermore, instead of defining the boundary line BL as the line that precisely includes the pen instruction position Po, it is also possible to define the boundary line BL as a line that includes the vicinity of the pen instruction position Po. If a margin is allowed when defining the boundary line BL, it is also possible to define the boundary line BL as a line that is in the vicinity of the pen instruction position Po and includes a position slightly to the left of the pen instruction position Po (or to the right in the case of left-handed users (the right-hand side of the frame area 162)). In the following explanation, it is assumed that the boundary line BL is set as the line that includes the pen instruction position Po.

[0051] However, considering the actual usage conditions of the input device 1, it is not the case that the usage condition is always limited to a state in which the lateral DRb of the input surface 11S of the input device 1 coincides with the lateral DRa of the user's chest when facing the input device 1 directly.

[0052] For example, as shown in Figure 4(B), the user may rotate the input device 1 with a rotation axis perpendicular to the input surface 11S and indicate the position with the electronic pen 3 being held. In this case, although the user is facing the input surface 11S of the input device 1, the lateral direction DRa of the user's chest and the lateral direction DRb of the input surface 11S of the input device 1 intersect at a predetermined angle corresponding to the rotation angle when the input device 1 is rotated. In this case, the plane containing the lateral direction DRa of the user's chest and the plane containing the lateral direction DRb of the input surface 11S of the input device 1 are different planes, and there is no plane containing both directions DRa and DRb.

[0053] Considering that a rotating platform is commercially available and in use that allows the input device 1 to rotate with a rotation axis perpendicular to its input surface 11S, it is likely that situations will frequently arise where the user provides instructions while the input device 1 is being rotated in this manner.

[0054] The same situation occurs when the user changes their position so as to rotate around the input device 1 without rotating the input device 1, resulting in the positional relationship shown in Figure 4(B), and then performs instruction input using the electronic pen 3.

[0055] Thus, if the lateral direction DRb of the input surface 11S of the input device 1 intersects at a predetermined angle with the lateral direction DRa of the user's chest when facing the input surface 11S of the input device 1, and the boundary line BL of the palm reject range on the input surface 11S is always parallel to the vertical direction of the rectangular input surface 11S, as shown in Figure 4(A), then, as shown in Figure 4(B), the palm area will be outside the palm reject range, and there is a risk of it being mistakenly detected as an electrostatic touch input. Figure 4(B) shows the case for a right-handed user, but it goes without saying that the same risk of palm misdetection can occur for left-handed users as well.

[0056] In this first embodiment of the input device 1, the tilt of the user's face in the captured image is detected from the image captured by the camera 4, and the palm rejection range is set by determining the boundary line BL of the palm rejection range using the detected tilt of the user's face in the captured image in addition to the pen instruction position Po of the electronic pen 3, thereby solving the above-mentioned problem.

[0057] In other words, in the image captured by the camera 4 of the user facing the input surface 11S of the input device 1, the face will be tilted according to the rotation angle when the input device 1 is rotated. In this embodiment, this is used to appropriately set the palm reject range by tilting the boundary line BL of the palm reject range with respect to the vertical direction of the input surface 11S according to the tilt of the face in the captured image. This will be further explained with reference to Figures 5 to 8. Figures 5 to 8 are for a right-handed user. In the example described below, the tilt of the face is detected as the tilt of the midline of the face.

[0058] As shown in Figure 5(A), when the lateral direction DRa of the user's chest, which is facing the input surface 11S of the input device 1, coincides with the lateral direction DRb of the input surface 11S (in this case, the lateral direction DRa of the user's chest and the lateral direction DRb of the input surface 11S of the input device 1 are contained in a single plane), the vertical direction of the image captured by the camera 4 (here, a rectangular image) coincides with the user's height. Therefore, in the state shown in Figure 5(A), as shown in Figure 5(B), the midline Cs of the user's face in the image 4P captured by the camera 4 coincides with the vertical direction of the image captured by the camera 4 (the vertical direction of the image frame), and the inclination of the midline Cs, i.e., the inclination of the user's face, is 0°.

[0059] In this embodiment, in the state shown in Figure 5(A), the boundary line BL of the palm reject range on the input surface 11S of the input device 1 is set to pass through the pen instruction position Po and be parallel to the vertical direction of the input surface 11S, as shown in Figure 5(C), in line with a tilt of 0° of the midline Cs of the face. The palm reject range is set to the right side of the frame region 162, which is to the right of this boundary line BL. As described above, this sets the boundary line BL of the palm reject range so that the palm can be detected well.

[0060] Next, consider the case where the user inputs instructions using the electronic pen 3 while the input device 1 is rotated by n° counterclockwise from the state shown in Figure 5(A). Then, as shown in Figure 6(A), the lateral direction DRa of the user's chest, which is directly facing the input surface 11S of the input device 1, and the lateral direction DRb of the input surface 11S intersect at an angle of n°. In this case, the lateral direction DRa of the user's chest and the lateral direction DRb of the input surface 11S of the input device 1 are not included in the same plane. Furthermore, the midline Cs of the user's face in the image 4P captured by the camera 4 is tilted by n° clockwise with respect to the vertical direction of the image captured by the camera 4, as shown in Figure 6(B).

[0061] In this embodiment, in the state shown in Figure 6(A), the boundary line BL of the palm reject range on the input surface 11S of the input device 1 is set as a line that passes through the pen instruction position Po and is tilted n° clockwise with respect to the vertical direction of the input surface 11S, as shown in Figure 6(C), in accordance with the inclination n° of the midline Cs of the user's face. The palm reject range is set as the right-hand side of the frame region 162, which is to the right of this boundary line BL. The direction of the boundary line BL of the palm reject range in Figure 6(C) is the same as in the case of Figure 5(A) where the input surface 11S of the input device 1 is not rotated, when viewed from the user's side. As a result, the boundary line BL of the palm reject range is set so that the palm can be detected well.

[0062] Next, Figure 7(A) shows the state in which the user is giving instructions using the electronic pen 3, with the input device 1 rotated 90° counterclockwise from the state shown in Figure 5(A). In this case, the lateral direction DRa of the user's chest, which is facing the input surface 11S of the input device 1, and the lateral direction DRb of the input surface 11S intersect at a 90° angle. As a result, the midline Cs of the user's face in the image 4P captured by the camera 4 is tilted 90° clockwise with respect to the vertical direction of the camera's frame, as shown in Figure 7(B).

[0063] In this embodiment, in the state shown in Figure 7(A), the boundary line BL of the palm reject range on the input surface 11S of the input device 1 is set to be a line parallel to the horizontal direction, passing through the pen instruction position Po and tilted 90° clockwise with respect to the vertical direction of the input surface 11S, as shown in Figure 7(C), in line with the 90° inclination of the midline Cs. The palm reject range is set to the lower edge of the frame region 162, to the right of this boundary line BL in Figure 7(C). As a result, even in the state shown in Figure 7(A), the boundary line BL of the palm reject range is set so that the palm can be detected well.

[0064] Furthermore, Figure 8(A) shows the state in which the input device 1 has been rotated 180° counterclockwise from the state in Figure 5(A), that is, the upper and lower edges of the frame area 162 have been reversed, and the user is making input using the electronic pen 3. In this case, the lateral direction DRa of the user's chest, which is facing the input surface 11S of the input device 1, and the lateral direction DRb of the input surface 11S coincide. As shown in Figure 8(B), the midline Cs of the user's face in the image 4P captured by the camera 4 is tilted 180° clockwise with respect to the vertical direction of the camera's frame, so it coincides with the vertical direction of the captured image, but the face is upside down.

[0065] In this embodiment, in the state shown in Figure 8(A), the boundary line BL of the palm reject range on the input surface 11S of the input device 1 is set to pass through the pen instruction position Po and coincide with the vertical direction of the input surface 11S, as shown in Figure 8(C), in line with the 180° inclination of the midline Cs of the face. Since the user's face in the captured image is upside down, the palm reject range is set as the left-side region of the frame area 162, which is to the right of the boundary line BL in Figure 8(C) (in the state of the input surface 11S in Figure 5(C) where the input device 1 is not rotated, this is the left-side region of the frame area 162, which is to the left of the boundary line BL). As a result, even when the input device 1 shown in Figure 8(A) is rotated halfway, the boundary line BL of the palm reject range is set so that the palm can be detected well.

[0066] As described above, the tilt of the midline of the user's face in the image captured by camera 4, that is, the tilt of the user's face in the captured image, corresponds to the rotation angle when the input surface 11S of the input device 1 rotates with a rotation axis perpendicular to the input surface 11S, or corresponds to the rotation angle when the user makes an instruction input with an electronic pen from an oblique direction while rotating around the input surface of the input device.

[0067] In this embodiment, the boundary line BL of the palm rejection range on the input surface 11S of the input device 1 is set as a line that includes the pen instruction position by the electronic pen 3, and the direction of the boundary line BL of the palm rejection range on the input surface 11S of the input device 1 is determined according to the tilt of the face in the image captured by the camera 4. In this way, the direction of the set boundary line BL of the palm rejection range is always in a direction that extends downward from the pen instruction position when viewed from the user's side. Therefore, the palm rejection range set in the input device 1 of this embodiment is set as an appropriate range that includes the position of the palm, even if the input device 1 is rotated or the user changes position around the input device 1.

[0068] The above explanation describes the case where the user is right-handed. However, if the user is left-handed and holds the electronic pen in their left hand to input pen commands, the palm reject range is set to the left of the boundary line BL in Figure 5(C). In addition, the palm reject range can be set in the same way as for the right-handed user described above, including setting the boundary line BL as a line that includes the pen command position, and determining the direction of the boundary line BL on the input surface 11S according to the inclination of the midline of the user's face in the image captured by the camera 4.

[0069] <Example of the configuration of the main part of the processing control circuit 104> In order to realize what has been described above, the processing control circuit 104 of the control unit 100 includes, as shown in Figure 3, a palm rejection range setting unit 1042 and a dominant hand information acquisition unit 1043 as functional means, in addition to the palm rejection function unit 1041 mentioned above.

[0070] As described above, the palm rejection function unit 1041 is a function unit that determines whether the touch position detected by the touch position detection circuit 102 is a palm touch when the pen instruction position detection circuit 103 detects the pen instruction position by the electronic pen 3, and ignores the touch when it is determined to be a palm touch.

[0071] The dominant hand information acquisition unit 1043 monitors the operation status of the dominant hand notification operation units 5R and 5L to acquire dominant hand information. When the dominant hand information acquisition unit 1043 detects that the dominant hand notification operation unit 5R has been pressed and turned on, it acquires dominant hand information indicating that the user's dominant hand is the right hand and controls the dominant hand indicator 6R to light up. Also, when the dominant hand information acquisition unit 1043 detects that the dominant hand notification operation unit 5L has been pressed and turned on, it acquires dominant hand information indicating that the user's dominant hand is the left hand and controls the dominant hand indicator 6L to light up.

[0072] As mentioned above, the palm reject range setting unit 1042 sets the palm reject range based on the pen instruction position detected by the pen instruction position detection circuit 103, the tilt of the face midline obtained from the image of the user's face captured by the camera 4 via the amplifier 105, and the dominant hand information obtained by the dominant hand information acquisition unit 1043.

[0073] In this embodiment, the palm reject range setting unit 1042 detects facial features such as eyes, nose, mouth, and ears from the captured image of the user's face input through the amplifier 105, and uses these facial features to identify (detect) the midline of the user's face. In this example, the palm reject range setting unit 1042 finds a straight line segment connecting the two eyes detected as facial features, and identifies the midline of the face as a line perpendicular to that segment at the center point of that segment.

[0074] The method for identifying the midline from facial features is not limited to this example. For example, the facial midline may be detected as the extension of the line connecting the center position of the nose in the width direction and the center position of the mouth in the width direction, which are detected as facial features. Alternatively, the facial midline may be detected as the extension of the line connecting the center point of the line segment connecting both eyes and the center position of the nose in the width direction and / or the center position of the mouth in the width direction. Furthermore, other methods can be used to determine the facial midline using two of the eyes, nose, mouth, and ears detected as facial features, or using all four facial features.

[0075] The palm reject range setting unit 1042 determines the inclination of the midline of the identified user's face as the angle it makes with the vertical direction of the captured image (which coincides with the vertical direction of the image frame), and in this embodiment, the inclination of the midline of the face in the captured image is detected as the inclination of the face in the captured image.

[0076] Then, the palm reject range setting unit 1042 identifies the boundary line BL of the palm reject range based on the tilt of the face in the acquired image and the pen instruction position detected by the pen instruction position detection circuit 103, as described above. Furthermore, the palm reject range setting unit 1042 sets the area to the right or left of the boundary line BL of the palm reject range as the palm reject range, based on the dominant hand information from the dominant hand information acquisition unit 1043.

[0077] The palm rejection range setting unit 1042 supplies the set palm rejection range information to the palm rejection function unit 1041. The palm rejection function unit 1041 uses this palm rejection range information to perform palm rejection.

[0078] <Example of Processing Operation of Processing Control Circuit 104> An example of processing operation in the processing control circuit 104 of the control unit 100, which is configured as described above, will be explained below. First, an example of processing operation of the palm reject range setting unit 1042 of the processing control circuit 104 will be explained with reference to the flowcharts in Figures 9 and 10. In the following explanation, the processing of each step in the flowchart will be explained as being performed by the processing control circuit 104, which is composed of a computer (microprocessor).

[0079] The processing control circuit 104 monitors the detection output of the pen instruction position detection circuit 103 to determine whether or not a pen instruction position has been detected (step S101). Note that the detected pen instruction position may be in a hover state. If it is determined in step S101 that no pen instruction position has been detected, the processing control circuit 104 returns to step S101 and repeats this step S101.

[0080] In step S101, when it is determined that the pen input position has been detected, the processing control circuit 104 acquires the image captured from the camera 4 through the amplifier 105 (step S102). In this example, the camera 4 is activated based on the detection of the pen input position in step S101. The camera 4 may be kept activated at all times, or a camera activation button may be provided on the housing 16 so that the user can activate it by operating the camera activation button.

[0081] Next, the processing control circuit 104 detects and identifies the midline of the user's face in the acquired image as described above (step S103). Then, the processing control circuit 104 detects the inclination of the midline of the face in the image identified in step S103 as described above, and detects the tilt of the face in the image based on the detected inclination of the midline (step S104).

[0082] Next, the processing control circuit 104 sets the palm reject range using the pen instruction position detected in step S101, the tilt of the user's face in the captured image detected in step S104, and the dominant hand information acquired by the dominant hand information acquisition unit 1043, as described above, and temporarily stores this information (step S105).

[0083] Next, the processing control circuit 104 determines whether or not the pen input has ended (step S106). This determination is made based on, for example, whether or not the pen input has been detected for a predetermined period of time or longer. If the processing control circuit 104 determines in step S106 that the pen input has ended, it erases the temporarily stored palm reject range (step S107), and then returns the process to step S101.

[0084] If it is determined in step S106 that the pen input has not yet finished, the processing control circuit 104 determines whether the pen input position has changed (step S111 in Figure 10). If it is determined that the pen input position has changed, it changes the position of the boundary line BL of the palm reject range to match the changed pen input position and resets the palm reject range (step S112).

[0085] In step S111, when it is determined that the pen instruction position has not changed, and following step S112, the processing control circuit 104 determines whether or not it is time to acquire the captured image from the camera 4 (step S113). That is, in this embodiment, when the camera 4 is activated, the processing control circuit 104 acquires the captured image from the camera 4 at predetermined intervals, such as every few seconds, so in step S113, it determines whether or not it is time to acquire the image.

[0086] If, in step S113, it is determined that it is not yet time to acquire the image captured from camera 4, the processing control circuit 104 returns to step S106 in Figure 9 and repeats the process from step S106 onward.

[0087] In step S113, when it is determined that it is time to acquire the image captured from camera 4, the processing control circuit 104 acquires the image captured from camera 4, identifies the midline of the face in the image, and detects the tilt of the face in the image as the tilt of the midline (step S114). The processing control circuit 104 then determines whether or not the tilt of the face in the image has changed (step S115), and if it is determined that the tilt of the face in the image has changed, it changes the boundary line BL of the palm reject area to match the changed tilt of the face in the image (step S116).

[0088] Furthermore, if it is determined in step S115 that the tilt of the face in the captured image has not changed, and after step S116, the processing control circuit 104 returns the process to step S in Figure 9, and repeats the steps from step S106 onwards.

[0089] As described above, the palm reject range setting unit 1042 sets a palm reject range that dynamically changes in response to changes in the pen's indicated position and the user's face tilt.

[0090] In the example of the palm reject range setting unit 1042 described above, the tilt of the face's midline in the captured image is detected in step S114 each time an image is acquired from the camera 4, and based on the detected tilt of the face's midline, it is determined in step S115 whether or not the tilt of the face in the captured image has changed. However, it is also possible to determine whether or not the tilt of the face in the captured image has changed by another method before detecting the tilt of the face's midline in the captured image, and then, if it is determined that the tilt of the face in the captured image has changed as a result of that determination, the tilt of the face's midline in the captured image is detected and the palm reject range is changed.

[0091] Another example of a method for determining whether the tilt of the face in an captured image has changed is as follows. The first example involves detecting the position of the user's head from the image captured by camera 4 each time an image is acquired from camera 4, comparing the position of the user's head in the image captured by camera 4 at the current time with the position of the user's head in the image captured by camera 4 at the previous timing, and determining that the tilt of the face in the captured image has changed when the change in head position exceeds a predetermined value.

[0092] The second example involves detecting the user's facial features from the image captured by camera 4 each time an image is acquired from camera 4, comparing the position of the facial features acquired at the current time with the position of the facial features acquired at the previous time to detect the amount of movement of each facial feature, and determining that the tilt of the face in the captured image has changed if the amount of movement differs for each facial feature.

[0093] Next, an example of the processing operation performed by the processing control circuit 104 while palm rejection is performed by the palm rejection function unit 1041 using the palm rejection range set in the palm rejection range setting unit 1042 will be explained with reference to Figure 11.

[0094] The processing control circuit 104 monitors the detection output of the pen instruction position detection circuit 103 to determine whether or not a pen instruction position has been detected (step S121). Note that the detected pen instruction position may be in a hover state.

[0095] If, in step S121, it is determined that no pen input position has been detected, the processing control circuit 104 monitors the detection output of the touch position detection circuit 102 to determine whether or not a touch position has been detected (step S122). If, in step S122, it is determined that no touch position has been detected, the processing control circuit 104 returns to step S121. If, in step S122, it is determined that a touch position has been detected, the processing control circuit 104 uses the function of the palm rejection function unit 1041 to determine whether or not the touch is a palm touch (step S123). If it is determined that the touch is a palm touch, the detected touch position is ignored and the process returns to step S121.

[0096] Furthermore, if in step S123 it is determined that the touch is a finger touch instruction and not a palm touch, the processing control circuit 104 performs normal processing according to the detected touch position (step S124), and after the completion of that processing, the process returns to step S121.

[0097] Then, in step S121, when it is determined that the pen instruction position has been detected, the processing control circuit 104 determines whether or not a touch position has also been detected (step S125). In step S125, when it is determined that a touch position has not been detected simultaneously, the processing control circuit 104 performs normal processing according to the detected pen instruction position (step S126), and after the completion of that processing, the process returns to step S121.

[0098] Furthermore, if it is determined in step S125 that a touch position has been detected simultaneously, the processing control circuit 104 determines whether the touch is a palm touch or not based on the function of the palm rejection function unit 1041 (step S127). If it is determined that the touch is a palm touch, it ignores the detected touch position and proceeds to step S126 to perform normal processing according to the detected pen instruction position. After the completion of that processing, it returns to step S121.

[0099] Furthermore, if in step S127 the touch is determined to be a touch instruction made by a finger and not a palm, the processing control circuit 104 performs normal processing according to the pen instruction position and also performs normal processing according to the touch position (step S128). After the completion of step S128, the processing control circuit 104 returns to step S121 and repeats the processing from step S121 onward.

[0100] [Second Embodiment] In the input device 1 of the first embodiment described above, an electromagnetically coupled electronic pen 3 was used as the electronic pen, but the electronic pen may be an electrostatically coupled electronic pen. In the second embodiment described below, an active electrostatic electronic pen 3A is used as the electronic pen, so that the pen indication position indicated by the electronic pen 3A and the touch position by the user's finger 2F can be distinguished and detected.

[0101] Figure 12 shows an example of the electrical configuration of the input device 1A of this second embodiment. The hardware configuration of the input device 1A of this second embodiment is not shown here, but it is equivalent to the hardware configuration of the input device 1 of the first embodiment shown in Figure 2, with the pen instruction detection sensor 13 removed and the electromagnetic induction coupling type electronic pen 3A replaced with an active electrostatic type electronic pen 3A.

[0102] In other words, in this second embodiment of the input device 1A, the position detection sensor is provided only by an electrostatic coupling type position detection sensor 12A, and is not provided by an electromagnetic induction coupling type position detection sensor (pen instruction detection sensor) 13. Furthermore, in the second embodiment, a control unit 100A with the configuration shown in Figure 12 is used as the control unit formed on the control circuit board 14. The position detection sensor 12A has the same configuration as the touch detection sensor 12 of the input device 1 of the first embodiment, and in this second embodiment as well, it consists of a plurality of linear X conductors 12X1 to 12Xn (n = 1, 2, ...) arranged in the X axis direction (e.g., horizontal direction) on one surface of the insulating substrate, and a plurality of linear Y conductors 12Y1 to 12Ym (m = 1, 2, ...) arranged in the Y axis direction (e.g., vertical direction) on the other surface of the insulating substrate so as to intersect orthogonally with the plurality of X conductors 12X1 to 12Xn.

[0103] The input device 1A of this second embodiment, as shown in Figure 12, consists of a position detection sensor 12A and a control unit 100A connected to the position detection sensor 12A. The control unit 100A consists of a multiplexer 106 which serves as an input / output interface with the position detection sensor 12A, a display control circuit 101A, a touch position detection circuit 102A, a pen instruction position detection circuit 103A, and a processing control circuit 104A.

[0104] The multiplexer 106 includes a switching circuit function that, through switching control by the processing control circuit 104A, connects the position detection sensor 12A to either the touch position detection circuit 102A or the pen instruction position detection circuit 103A.

[0105] The touch position detection circuit 102A has the same configuration as the touch position detection circuit 102 in the first embodiment and is capable of simultaneously detecting the positions of multiple fingers 2F that touch at multiple different positions on the input surface 11S. In this embodiment, the touch position detection function of the touch position detection circuit 102A uses a transmission signal (spreading code in this example) with a frequency f1 of approximately 50 kHz to 200 kHz.

[0106] The pen instruction position detection circuit 103A detects the pen instruction position by the active electrostatic pen 3A on the position detection sensor 12A, that is, on the input surface 11S.

[0107] As shown in Figure 12, the active electrostatic pen 3A is equipped with an oscillator circuit 3S inside the pen case, and emits a signal with a frequency f2, different from the aforementioned frequency f1, for example, 1.8 MHz, from the electrodes at the tip of the pen. The oscillator circuit 3S may be composed of an oscillator, or it may be a circuit that generates a signal obtained by modulating or otherwise processing the oscillation signal generated by the oscillator. The pen position detection circuit 103A receives the signal from the active electrostatic pen 3A not only from the X conductors 12X1 to 12Xn of the position detection sensor 12A, but also from the Y conductors 12Y1 to 12Ym.

[0108] The pen position detection circuit 103A then checks the level of the 1.8 MHz signal received from the active electrostatic pen 3A for the X conductors 12X1 to 12Xn and the Y conductors 12Y1 to 12Ym, and detects the X conductors 12X and Y conductors 12Y where the 1.8 MHz signal is at a high level, thereby detecting the position indicated by the active electrostatic pen 3A. The pen position detection circuit 103A then supplies the detection result regarding the pen position indicated by the active electrostatic pen 3A to the processing control circuit 104A.

[0109] The processing control circuit 104A, like the processing control circuit 104 of the first embodiment, is composed of a computer (microprocessor), and in this second embodiment, the input device 1A controls the detection of touch position and the detection of pen instruction position in a time-division manner. That is, in this second embodiment, as shown in Figure 13, the input device 1A is configured to alternately execute a pen instruction position detection period TP, in which the detection of the pen instruction position is performed, and a touch position detection period TF, in which the detection of the touch position is performed, in a time-division manner.

[0110] In other words, during the pen instruction position detection period TP, the processing control circuit 104A controls the multiplexer 106 to connect the position detection sensor 12A to the pen instruction position detection circuit 103A, and also controls the pen instruction position detection circuit 103A to be in an operating state (active state).

[0111] The processing control circuit 104A also controls the multiplexer 106 to connect the position detection sensor 12A to the touch detection circuit 102A during the touch position detection period TF, and controls the touch detection circuit 102A to be in an operating state (active state).

[0112] As described above, the processing control circuit 104A controls the timing of the time-division processing between the pen instruction position detection period TP and the touch position detection period TF, and also controls the switching between the finger proximity detection function and the touch position detection function during the touch position detection period TF. As a result, in this embodiment, the position instruction by the finger 2F and the position instruction by the active electrostatic pen 3A can be detected substantially simultaneously.

[0113] Furthermore, the processing control circuit 104A of the input device 1A in this second embodiment is equipped with the same functional means as the palm rejection function unit 1041, palm rejection range setting unit 1042, and handedness information acquisition unit 1043 of the processing control circuit 104 in the first embodiment.

[0114] The input device 1A of this second embodiment also provides the same effects and advantages as the input device 1 of the first embodiment described above.

[0115] [Other Embodiments or Modifications] In the embodiments described above, the tilt of the face in the image captured by camera 4 was detected by identifying the midline of the face in the captured image and detecting the tilt of the midline. However, the method for detecting the tilt of the face from the captured image is not limited to the method using the midline. For example, as shown in Figure 14, the tilt of the face may be detected as the angle θ between the line L1 connecting both eyes, or the line L2 connecting both ears, which are detected as face parts in the captured image, and the horizontal direction of the captured image (the horizontal direction of the image frame).

[0116] Furthermore, instead of detecting the midline of the face, it is also possible to detect the angle between a line perpendicular to either the line connecting the eyes (L1) or the line connecting the ears (L2), which are detected as facial features in the captured image, and the vertical direction of the captured image, as the tilt angle of the face in the captured image.

[0117] Furthermore, as shown in Figure 15, a motion sensor 7, such as a gyro sensor, may be provided in the frame area 162 of the housing 16 of the input device 1. This motion sensor 7 may detect the direction and amount of rotation of the input device 1 with the rotation axis perpendicular to the input surface, as well as the direction and amount of lateral movement of the input device 1. The detected direction and amount of rotation, direction and amount of lateral movement, etc., may be used as auxiliary information when changing the palm rejection range setting in accordance with the change in the tilt of the face in the captured image.

[0118] In the above embodiment, the dominant hand information acquisition unit 1043 acquires dominant hand information as operation information through the dominant hand notification operation units 5R and 5L provided in the frame area 162 of the housing 16 of the input device 1. However, the method of acquiring dominant hand information is not limited to this. For example, when a user is holding the electronic pen 3 and making pen input, the direction of the tilt of the electronic pen is generally such that for a right-handed user, the electronic pen 3 is tilted downward to the right relative to the pen input position, and for a left-handed user, the electronic pen 3 is tilted downward to the right relative to the pen input position. Therefore, the input device 1 may detect the direction of the tilt of the electronic pen when the user is holding the electronic pen 3 and making pen input, and acquire dominant hand information based on the detection result.

[0119] Alternatively, handedness information may be acquired using the image captured by camera 4. That is, for example, the camera 4 may be used to capture an image of the user holding the electronic pen 3 in advance, and the input device 1, for example, the processing control circuit 104 or processing control circuit 104A, may use the captured image to determine whether the user is right-handed or left-handed and acquire handedness information.

[0120] 1, 1A...Input device, 2F...Finger, 3, 3A...Electronic pen, 4...Camera, 5R, 5L...Dominant hand notification operation unit, 11...Display device, 11S...Input surface, 12...Touch detection sensor, 12A...Position detection sensor, 13...Pen instruction detection sensor, 14...Control circuit board, 100, 100A...Control unit, 16...Housing, 162...Frame area, 102, 102A...Touch position detection circuit, 103, 103A...Pen instruction position detection circuit, 104, 104A...Processing control circuit, 1041...Palm rejection function unit, 1042...Palm rejection range setting unit, 1043...Dominant hand information acquisition unit,

Claims

1. An input device comprising: a pen instruction position detection unit for detecting the pen instruction position on an input surface by an electronic pen held by a user; a touch position detection unit for detecting the user's touch position on the input surface; an imaging unit mounted in a position capable of capturing images of the user's face as they hold the electronic pen; and a palm reject range setting unit for setting a palm reject range on the input surface based on the tilt of the user's face in the image captured by the imaging unit and the pen instruction position detected by the pen instruction position detection unit.

2. The input device according to claim 1, characterized in that the palm reject range setting unit determines the midline of the user's face from the captured image of the user's face, detects the inclination of the determined midline, detects the inclination of the face based on the detected inclination of the midline, and determines the boundary of the palm reject range on the input surface.

3. The input device according to claim 2, characterized in that the palm reject range setting unit detects facial parts from the image of the user's face captured by the imaging unit, determines the midline of the face from the detected facial parts, and detects the inclination of the midline.

4. The input device according to claim 1, characterized in that the palm reject range setting unit detects facial features from the image of the user's face captured by the imaging unit and determines the tilt of the face from the detected facial features.

5. The input device according to claim 3 or 4, characterized in that it detects two or more types of facial parts from among eyes, nose, mouth, and ears.

6. The input device according to claim 3 or 4, characterized in that it detects only the eyes among the facial parts.

7. The input device according to claim 1, wherein the palm reject range setting unit detects facial features from the image of the user's face captured by the imaging unit, determines the vertical relationship of the facial features in the captured image based on the positions of the detected facial features in the overall image of the face, and determines whether the face in the captured image of the captured result is upside down.

8. The input device according to claim 3, characterized in that the midline is detected as a line perpendicular to the line connecting the user's eyes.

9. The input device according to claim 3, characterized in that the midline is detected as a line passing through at least the user's nose and mouth.

10. The input device according to claim 1, further comprising a dominant hand information acquisition unit that acquires information on the user's dominant hand, wherein the palm reject range setting unit sets the palm reject range on the input surface based on the information on the user's dominant hand acquired by the dominant hand information acquisition unit.

11. The input device according to claim 1, wherein the imaging unit sequentially acquires the face images, and the palm reject range setting unit detects a change in the tilt of the face by comparing the current face image with a face image acquired at a previous point in time, and changes the palm reject range on the input surface when such change is detected.

12. The input device according to claim 11, characterized in that it detects a change in the tilt of the face by comparing the position of the head in the current face image with the position of the head in the face image acquired at a previous point in time.

13. The input device according to claim 11, characterized in that it detects a change in the tilt of the face by comparing the position of the facial parts in the current image of the face with the position of the facial parts in the image of the face acquired at a previous point in time.

14. The input device according to claim 1, further comprising a motion sensor for detecting the rotational displacement of the input surface about a rotation axis perpendicular to the input surface, wherein the palm reject range setting unit uses the rotational displacement detected by the motion sensor to set the palm reject range on the input surface.

15. The input device according to claim 1, characterized in that a frame is provided around the input surface, and the imaging unit is provided in the frame.

16. The input device according to claim 1, characterized in that the imaging unit is provided at the central position of the upper part of the input surface of the frame.

17. The input device according to claim 1, characterized in that the touch position detection unit comprises a first sensor of the electrostatic coupling type and a first position detection circuit, the pen instruction position detection unit comprises a second sensor of the electromagnetic induction type and a second position detection circuit, and the first sensor and the second sensor are arranged to overlap in a direction perpendicular to the input surface.

18. The input device according to claim 1, wherein the touch position detection unit comprises a first electrostatically coupled sensor and a first position detection circuit for detecting the touch, the pen instruction position detection unit comprises the first sensor and a second position detection circuit for receiving a signal from an electrostatically coupled electronic pen to the first sensor and detecting the instruction position by the electrostatically coupled electronic pen, and the first position detection circuit and the second position detection circuit are operated in a time-division manner.

19. A palm reject range setting method for an input device comprising: a pen instruction position detection unit for detecting the pen instruction position on an input surface by an electronic pen held by a user; a touch position detection unit for detecting the user's touch position on the input surface; and an imaging unit mounted in a position capable of photographing the face of a user holding the electronic pen, the method comprising: a first step of determining the face parts from an image of the user's face; a second step of detecting the tilt of the user's face in the image from the face parts determined in the first step; and a third step of determining the boundary of the palm reject range on the input surface and setting the palm reject range based on the tilt of the user's face in the image detected in the second step.

Images