JP2017074713A - Conductive eraser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive eraser that can erase writing data converted into data by a writing board together with writing that is an original form of the writing data.SOLUTION: The conductive eraser used for the writing board including a projection-type electrostatic capacity coupling-system touch sensor includes: a resin capable of erasing a writing content written on a writing sheet by a writing instrument with a tip containing black lead; and a conductive particle contained to the resin by an amount the touch sensor can detect.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a conductive eraser used for a writing board that supports a writing sheet such as paper as a medium for writing.

  2. Description of the Related Art Conventionally, a handwriting input support device that enables handwriting input to a computer or the like is known. For example, Patent Literature 1 discloses a handwriting input support device that includes a position detection device having an input surface and a pen-type position indicator having a pen tip for performing input to the input surface of the position detection device. Has been.

JP 2010-117943 A

  In the conventional handwriting input support device as shown in Patent Document 1, since the input to the input surface of the position detection device is performed using a dedicated pen-type position indicator, the input to the input surface is not performed. The trajectory (handwriting) was not visible, causing inconvenience. Specifically, once the pen is moved away from the input surface during handwriting input, it is difficult to continuously input to an accurate position corresponding to the trajectory because the input trajectory until then cannot be visually recognized. .

  Further, the conventional handwriting input support device requires a dedicated pen (pen-type position indicator) for performing input to the input surface of the position detection device. For this reason, there is a problem that the configuration of the entire handwriting input support device is complicated and the cost of the device increases. There is also a problem that the handwriting input support device cannot be used if the dedicated pen is lost.

  For example, there is a desire to use such a handwriting input support device at educational sites such as elementary school, junior high school, and high school. In an educational setting, it is desired to recognize writing information as data using a handwriting input support device on the premise that writing and erasing on paper or the like is performed by a general method using a general-purpose pencil and an eraser. However, in the conventional handwriting input support device, it is not possible to appropriately recognize input and erasure by a pencil and an eraser.

  The present invention has been made in consideration of the above points, and an object thereof is to provide a conductive eraser capable of erasing writing data converted into data by a writing board together with writing that is the basis of the writing data. To do.

  The conductive eraser of the present invention is a conductive eraser used in a writing boat having a projected capacitively coupled touch center, and is written on a writing sheet with a writing tool having a graphite-containing core. It has resin which can erase written contents, and conductive particles contained in an amount that can be detected by the touch sensor with respect to the resin.

  In the conductive eraser of the present invention, the conductive fine particles contain a carbon material.

  According to the present invention, writing data converted into data by a writing board can be erased together with writing that is the source of the writing data, and even if there is erasure, it is possible to perform appropriate handwriting input to a computer or the like. is there.

FIG. 1A is an external perspective view of the writing board system 10, and FIG. 1B is a cross-sectional view of the writing board 11. FIG. 2 is a cross-sectional view for explaining the layer structure of the detection means 30 of the writing board 11. FIG. 3 is a plan view showing the touch sensor 32 of the writing board 11. FIG. 4 is a partially enlarged view of the touch sensor 32 of FIG. 3 and shows a conductive mesh of the touch sensor. FIG. 5 is a perspective view for explaining the conductive eraser 51. FIG. 6 is a diagram for explaining a writing scene. FIG. 7 is a diagram for explaining an erasing scene. FIG. 8 is a diagram for explaining an example of determination of writing and erasing. FIG. 9 is a diagram for explaining another example of determination of writing and erasing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings attached to the present specification, for the sake of illustration and ease of understanding, the scale and vertical / horizontal dimension ratios may be appropriately changed and exaggerated from those of the actual ones.

In this specification, the terms “plate”, “sheet”, and “film” are not distinguished from each other only based on the difference in designation. For example, “sheet” is a concept that includes a member that can be called a plate or a film. Therefore, “display sheet” is different from a member called “display plate” or “display film” only in a difference in name. Cannot be distinguished.
In addition, “sheet surface (plate surface, film surface)” means a target sheet-like member (plate-like) when the target sheet-like (plate-like, film-like) member is viewed as a whole and globally. It refers to the surface that coincides with the plane direction of the member or film-like member.

  Furthermore, the shape and geometric conditions used in the present specification and the degree thereof are specified. For example, terms such as “parallel”, “orthogonal”, “identical”, length and angle values, etc. are strictly Without being bound by meaning, it should be interpreted including the extent to which similar functions can be expected.

  Fig.1 (a) is a perspective view which shows the outline of the writing boat system 10 which is one form. As can be seen from FIG. 1A, the writing board system 10 includes a writing board 11 and a conductive eraser 51.

  FIG. 1B is a cross-sectional view schematically showing the writing board 11 cut along the line Ib-Ib shown in FIG. FIG. 2B is a diagram for enlarging the portion indicated by II in FIG. 1B and explaining the layer configuration of the detection means 30. In FIG. 2, the layers are separated from each other for easy understanding, but actually, these layers are bonded by OCA (Optical Clear Adhesive, optical glue).

  As can be seen from FIGS. 1A, 1 </ b> B, and 2, the writing boat 11 includes a housing 12, a control unit 20 that is housed inside the housing 12, and a detection unit 30. Configured.

The housing 12 is a hollow box-like member that forms the outline of the writing board 11 and has the required strength and scratch resistance. Although the material for that is not specifically limited, For example, it may be comprised from resin materials, such as ABS resin and polycarbonate resin.
Inside the housing 12, the control means 20 and the detection means 30 are housed. Therefore, the housing 12 also includes a control unit 13 that is a part in which the control unit 20 is stored and a detection unit 14 in which the detection unit 30 is stored.
In particular, in the detection unit 14, the plate on the side having the support surface 14 a on which a writing sheet such as paper is placed is also configured to serve as the surface layer plate 31 of the detection means 30. The surface layer plate 31 will be described in detail later as the surface layer plate 31.

  The control means 20 has a control circuit board connected to the detection means 30. This circuit includes, for example, a control unit and a communication unit.

The control unit has a CPU (Central Processing Unit) and controls the entire writing board 11. The control unit is provided with a ROM (Read Only Memory) and a RAM (Random Access Memory) as required, and a program stored in the ROM is expanded in the RAM and the program is executed by the CPU. Good.
The program stored in the ROM determines whether to use the pencil 5 or the conductive eraser 51 based on a signal from the touch panel sensor 32 included in the detection means 30, and the position and range where these are used. A program for calculating a locus and obtaining written data and erasure data may be included.

  The communication unit is for communicating with an external device such as a computer or a display device, and has an interface device used for communication with the external device. As this interface device, a wired connection device for connection by a wired LAN (Local Area Network), a USB (Universal Serial Bus) connection, etc., and a wireless LAN, Bluetooth (registered trademark), NFC (Near Field Communication), A wireless connection device for performing connection by RFID (Radio Frequency Identification), infrared rays or the like can be exemplified.

  The writing board 11 has a power source (not shown) for supplying power to each part of the writing board 11. Examples of the power source include batteries such as lithium ion batteries and nickel metal hydride batteries. Further, the present invention is not limited to this, and an alternating current (AC) power source, a solar battery, or power supplied from a USB terminal may be used as the power source. The power source may be accommodated in either the circuit means 20 or the detection means 30. The power source may be configured as a separate body and connected to the control means 20 and the detection means 30.

  Next, the detection means 30 will be described. In this embodiment, as can be seen from FIG. 2, the detection means 30 includes a surface layer plate 31, a touch sensor 32, a shielding film 40, and a reinforcing plate 41 in order from the support surface 14 a of the housing 12.

In this embodiment, the surface layer plate 31 is a plate-like member configured to serve also as a part of the detection unit 14 of the housing 12, and is a light-transmitting layer that functions as a dielectric. The surface layer plate 31 functions as an input surface (touch surface, contact surface) for the detection unit 30. That is, an external conductor (for example, a writing instrument, a human finger, a conductive eraser 51, etc.) is brought into contact (approached) with the surface layer plate 31, thereby causing the touch sensor 32 to detect this and inputting information from the outside. Therefore, the thickness of the surface layer plate 31 is not particularly limited, but is preferably 0.1 mm or more and 0.6 mm or less.
As described above, the surface layer plate 31 also serves as a part of the housing 12 and forms the support surface 14a that supports the writing sheet.

  The support surface 14a of the surface layer plate 31 preferably has a hard coat property. Such a surface layer plate 31 can be produced, for example, by providing a hard coat layer 31b on a transparent support 31a formed of an acrylic resin or the like. This hard coat layer preferably has a hardness of “H” or more in a pencil hardness test (4.9 N load) defined by JIS K 5600-5-4: 1999. By setting the pencil hardness to “H” or higher, the scratch resistance of the surface layer plate 31 can be improved. Therefore, it is possible to prevent the support surface 14a from being damaged when the surface layer plate 31 is scratched by the tip of the writing instrument. Note that the upper limit of the pencil hardness of the hard coat layer 31b is preferably “4H” from the viewpoint of adhesion to the transparent support 31a, toughness, and curl prevention. That is, it is preferable that the hard coat layer 31b has a hardness of “H” or more and “4H” or less in a pencil hardness test (4.9 N load) defined by JIS K5600-5-4 (1999). Since the detection means 30 of the writing board 11 is repeatedly pressed and requires high adhesion and toughness, the hard coat layer 31b is detected by setting the upper limit of the pencil hardness of the hard coat layer 31b to “4H”. When used as a layer forming the support surface 14a of the means, a remarkable effect can be exhibited.

  As such a hard coat layer 31b, a layer of glass or resin can be used. For example, thermosetting resins such as fluororesins and silicon resins, ionizing radiation curable resins such as acrylic and epoxy resins that are cured by crosslinking reaction upon irradiation with ionizing radiation such as ultraviolet rays and electron beams, and ionizing radiation curable A resin obtained by adding a thermosetting resin such as a fluororesin or a silicon resin to the resin can be preferably used.

  Further, the hard coat layer 31b suppresses adhesion of graphite powder or ink from the written surface of the writing sheet, so-called setback, when the written writing sheet is turned over on the surface layer plate 31. It is preferred to use the material obtained. Furthermore, it is preferable to use a material that can be easily wiped off and removed, such as adhering graphite powder and ink, even if settling occurs.

  The hard coat layer 31b may be formed by applying a resin material on the transparent support 31a and curing it by heating, irradiation with ionizing radiation, or the like, or transparent a glass or resin sheet with an adhesive or an adhesive. You may affix on the support body 31a. When the hard coat layer 31b is formed by sticking a resin sheet to the transparent support 31a, for example, a resin material applied on a support film and cured by heating or irradiation with ionizing radiation, You may make it stick on the transparent support body 31a.

  Such a surface layer plate 31 preferably has a thickness of 0.1 mm or more and 0.6 mm or less from the viewpoint of supporting the writing sheet and reducing the thickness of the detection means 30. Moreover, it is preferable that the hard coat layer 31b has a thickness of 1 μm or more and 20 μm or less from the viewpoint of ensuring hardness and thinning of the detection means.

  Next, the touch sensor 32 will be described. FIG. 3 is a plan view showing an example of the touch sensor 32, and FIG. 4 is a partially enlarged view of the touch sensor 32 of FIG. 3, showing a conductive mesh 36 of the touch sensor 32. As shown in FIG.

  The touch sensor 32 is configured as a projected capacitive coupling method, and can detect a contact position of an external conductor (for example, a writing instrument, a human finger, etc.). When the detection sensitivity of the capacitive coupling type detection means 30 is excellent, it is possible to detect which area of the detection means 30 the external conductor is approaching simply by approaching the detection means 30. can do. Along with such a phenomenon, the “contact position” used here is a concept including an approach position that is not actually in contact but can be detected.

  The terms “capacitive coupling” and “projection type” capacitive coupling have the same meaning as that used in the technical field of touch sensors, and are used in this case. The “capacitive coupling” method is also called “capacitance” method, “capacitance coupling” method, etc. in the technical field of touch sensors. It is treated as a term synonymous with the “capacitive coupling” method. A typical capacitive coupling type touch sensor includes an electrode (conductor layer). When an external conductor comes into contact with the touch sensor, the external conductor and the electrode (conductor layer) of the touch sensor are connected. A capacitor (capacitance) is formed between them. Based on the change in the electrical state accompanying the formation of the capacitor, the position coordinates of the position where the external conductor is in contact (approaching) on the touch sensor are specified (position detection).

  The touch sensor 32 includes a support film 33, a first electrode (detection electrode) 34, a second electrode (detection electrode) 35, a first extraction wiring 34b, and a second extraction wiring 35b. In the example shown in FIGS. 2 to 4, the touch sensor 32 has a first electrode 34, a second electrode 35, a first extraction wiring 34 b, and a second extraction wiring 35 b on one surface of the support film 33. doing.

  Further, the touch sensor is not limited to this, and the touch sensor has the first electrode and the first extraction wiring on one surface of the support film, and the second electrode and the second extraction wiring on the other surface. Also good. Alternatively, the touch sensor having the first electrode and the first extraction wiring is laminated on one support film, and the touch sensor having the second electrode and the second extraction wiring is laminated on the other support film. Also good.

  In the example shown in FIGS. 2 to 4, the support film 33 supports the electrodes 34 and 35 and the extraction wirings 34 b and 35 b and can also function as a dielectric in the touch panel sensor 32. As shown in FIGS. 3 and 4, the support film 33 includes an active area Aa1 corresponding to an area where the touch position can be detected, and an inactive area Aa2 adjacent to the active area Aa1 and corresponding to an area where the touch position cannot be detected. And.

  The support film 33 is made of, for example, a polyester resin such as polyethylene terephthalate or polyethylene naphthalate, an acrylic resin such as polymethyl methacrylate, a polyolefin resin such as polypropylene, a cellulose resin such as triacetyl cellulose (cellulose triacetate), a polycarbonate resin, or the like. A material that can function as a dielectric, such as a resin sheet, an inorganic material made of glass, ceramics, or the like, can be used. Further, from the viewpoint of retaining the electrodes 34 and 35 and the extraction wirings 34b and 35b and reducing the thickness of the detection means 30, the thickness of the support film 33 can be set to 20 μm or more and 200 μm or less.

  As shown in FIG. 3, the first electrode 34 includes a plurality of first detection electrodes 34a used for position detection and disposed in the active area Aa1. In the illustrated example, the first detection electrodes 34a extend along the first direction (X) of the support film 33 and are arranged along the second direction (Y). The second electrode 35 includes a plurality of second detection electrodes 35a used for position detection and disposed in the active area Aa1. In the illustrated example, the second detection electrodes 35a extend along the second direction (Y) of the base film 33 and are arranged along the first direction (X). As an example, the first detection electrode 34a and the second detection electrode 35a are formed by a conductive mesh 36 composed of conductive thin wires 37 as described below. However, in FIG. A region where the first detection electrode 34a and the second detection electrode 35a are disposed is indicated by a simple rectangle. 3 and 4, in order to distinguish the first electrode 34 and the first extraction wiring 34b from the second electrode 35 and the second extraction wiring 35b for easy understanding, the first electrode 34 and the first extraction wiring 35b are used. The wiring 34b is indicated by a solid line, and the second electrode 35 and the second extraction wiring 35b are indicated by a broken line.

  The first detection electrode 34 a and the second detection electrode 35 a are provided for detecting an electromagnetic change or a change in capacitance that occurs when the outer conductor approaches the detection means 30. The first detection electrode 34a and the second detection electrode 35a can be constituted by, for example, a conductive mesh 36 made of a thin conductive wire 37 made of a metal material with a predetermined line width and thickness. The first detection electrode 34a and the second detection 34a are not limited to this, and may be formed using a transparent conductive film such as ITO (indium tin oxide).

  The pitch of the first detection electrodes 34a and the second detection electrodes 35a is preferably 3 mm or less. Thereby, it can be judged more appropriately and accurately whether writing with a pencil as described later or erasing with a conductive eraser. Moreover, it is preferable that the thickness of the 1st sensing electrode 34a and the 2nd sensing electrode 35a is 2 micrometers or less.

  One or two of the first extraction wiring 34b and the second extraction wiring 35b are provided for each of the first detection electrode 34a and the second detection electrode 35a depending on the detection method of the contact position. The first extraction wiring 34b and the second extraction wiring 35b are connected to the corresponding first detection electrode 34a and second detection electrode 35a to form a wiring. In the example shown in FIG. 3, the first extraction wiring 34 b and the second extraction wiring 35 b are formed in the inactive area Aa of the support film 33 from the corresponding first detection electrode 34 a and second detection electrode 35 a to the support film 33. It extends to the vicinity of the edge. Further, in the illustrated example, the first extraction wiring 34b and the second extraction wiring 35b have terminal portions 34c and 35c connected to the above-described control unit via connection wiring (for example, a flexible printed circuit board) (not illustrated). Contains.

  In the example shown in FIG. 4, the first electrode 34 and the second electrode 35 each include a conductive mesh 36. In the illustrated example, each of the first detection electrode 34 a and the second detection electrode 35 a includes a conductive mesh 36. The conductive mesh 36 is a mesh-like (lattice-like) material in which a large number of open regions 38 are defined by a large number of thin conductive wires 37. In the illustrated example, the conductive mesh 36 is formed as a grid-like mesh with a large number of conductive thin wires 37, thereby defining a large number of rectangular opening regions 38.

  As described above, the first electrode 34, the second electrode 35, the first extraction wiring 34b, and the second extraction wiring 35b are made of, for example, gold, silver, or the like by vapor deposition, sputtering, foil transfer, coating, or the like. A metal film containing one or more of copper, platinum, tin, aluminum, chromium, molybdenum, nickel, titanium, palladium, indium, and an alloy containing one or more of these metals is formed on the support film 33. The metal film can be formed by etching with a desired pattern.

Next, the shielding film 40 will be described. The shielding film 40 prevents external noise from affecting the touch sensor 32. Therefore, it is sufficient that such noise can be shielded. Examples thereof include conductive plastics, transparent conductive films such as ITO (indium tin oxide), and silver nanowire transparent conductive films.
Since the thickness of the shielding film 40 should just be able to shield a noise as mentioned above, what is necessary is just the thickness for it. For that purpose, the preferable thickness of the shielding film is 20 μm or more and 100 μm or less. In particular, the shielding film is composed of a shielding layer and a base film, and the preferred thickness of the shielding layer is 0.1 μm or more and 10 μm or less.

  The reinforcing plate 41 is a plate-like member that reinforces the strength of the detection means 30. Accordingly, the material and thickness of the detecting means 30 are not particularly limited as long as the necessary strength is given to the detecting means 30.

  In the detection means 30 as described above, the touch sensor 32 must be disposed closer to the support surface 14a than the shielding film 40. If this is reversed, the touch sensor 32 cannot be detected by the shielding film 40.

  Further, by connecting a display device such as a liquid crystal display to the writing board 11 via the communication unit described above, the writing content on the writing sheet placed on the support surface 14a of the writing board 11 is displayed on the display device. It is possible to construct a display system for displaying on the screen. In this display system, for example, the writing board 11 may be connected to the computer connected to the display device by wire or wirelessly, and the writing board 11 and the display device may be connected via the computer.

  Note that the writing board 11 may be provided with a storage device that can store the track data of the external conductor and the like. For example, a flash memory can be used as the storage device. Further, a removable external storage device such as a USB flash memory or a memory card may be used as the storage device.

  Next, returning to FIG. 1A, the conductive eraser 51 will be described. The conductive eraser 51 has a function of erasing the written contents written on the writing sheet. As shown in FIG. 5, the conductive eraser 51 has a main body portion 52 containing a resin and conductive particles 53 dispersed in the main body portion 52. In the present embodiment, the term “particle” includes a concept including what can be called powder or powder.

  The main body 52 includes a resin for erasing written contents (handwriting) written on a writing sheet with a writing instrument having a graphite core such as a pencil or a mechanical pencil. Examples of this resin include vinyl chloride resins such as polyvinyl chloride (PVC), natural rubber, and synthetic rubber. Furthermore, the main body 52 can include a plasticizer, a colorant, and the like in addition to the above-described resin. As the plasticizer, for example, a phthalic plasticizer such as dioctyl phthalate (DOP) or a non-phthalic plasticizer can be used. As the colorant, for example, dyes or pigments such as red, blue, yellow, black, and white can be used. As an example, when the conductive eraser 52 is dispersed in the main body 52 of the conductive eraser 51 so that the conductive eraser 52 is visually colored and grayed as a whole, the main body 52 of the conductive eraser 51 is white. By containing the dye or pigment, the conductive eraser 52 as a whole can be visually recognized as substantially white.

  The conductive particles 53 have a function that enables the conductive eraser 52 to be detected by the touch sensor 32 of the writing board 11. As this electroconductive particle 53, the particle | grains containing a metal or the particle | grains containing a carbon material can be used, for example. Examples of the metal-containing particles include gold, silver, copper, platinum, aluminum, iron, tin, nickel, and particles containing one or more alloys including one or more of these metals. Examples of the particles containing a carbon material include graphite, particles containing carbon nanotubes, carbon black, carbon fiber, and graphite. However, since particles containing metal have the possibility of generating rust, particles containing a carbon material are preferably used.

  As the conductive particles 53, particles having various shapes such as a spherical shape, a needle shape, and a scale shape can be used. Further, the conductive particles 53 may be indefinite.

  The average particle diameter of the conductive particles 53 can be 10 nm or more and 200 μm or less. Preferably, the average particle diameter of the conductive particles 53 can be 20 nm or more and 50 μm or less. According to the conductive eraser 51 in which the conductive particles 53 having such a particle size are dispersed, the conductive eraser 51 can be accurately detected by the touch sensor 32 of the writing board 11, and the conductive particles 53. Can be satisfactorily held in the main body 52 of the conductive eraser 51. The average particle diameter is an arithmetic average value of the diameter of the conductive particles 53 photographed by optical microscopy or transmission electron microscopy, and is described in the appendix of JIS Z 8901: 2006 (test powder and test particles). It can be specified as the arithmetic average particle size measured by the prescribed method.

  Further, the conductive particles 53 may be subjected to a surface treatment for improving dispersibility with respect to the resin contained in the main body portion 52. Further, a surface treatment for preventing oxidation of the conductive particles 53 may be performed.

  Although content of the electroconductive particle 53 in the electroconductive eraser 51 is not specifically limited, As an example, 10 mass parts or more of the electroconductive particle 53 with respect to 100 mass parts of the main body part (excluding the electroconductive particle 53) 52 is included. It can be contained at a ratio of 50 parts by mass or less. Preferably, the conductive particles 53 can be contained in an amount of 20 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the main body part 52. According to the conductive eraser 51 having the conductive particles 53 having such a content, the conductive eraser 51 can be accurately detected by the touch sensor 32 of the writing board 11 and written on the writing sheet. Good erasability of written contents can be ensured. Here, the performance as the eraser of the conductive eraser 51 is evaluated according to JIS S 6050-2002, and it is only necessary to have the eraser performance.

The inventor produced the following conductive eraser as one example. That is, the following main agent, plasticizer, organic solvent, and conductive filler were mixed with a mixer, then poured into a mold, heated and pressurized at 100 ° C. for 15 minutes.
Main agent: 50 parts by weight of vinyl chloride paste resin Plasticizer: 35 parts by weight of benzoflex Organic solvent: 15 parts by weight of polypropylene carbonate Conductive filler: 10 parts by weight of nanocarbon fine particles

  Then, the writing sheet (paper) installed on the writing boat 11 was written with a pencil to obtain writing on the writing sheet, and the contents of writing were obtained as data. The writing was then erased with the conductive eraser produced above. As a result, the characters were erased on the writing sheet, and the writing as data could be erased appropriately.

  Next, the operation of the writing board system 10 will be described.

  FIG. 6 shows one scene where writing detection is performed by the writing board 11. At this time, when the control means 20 detects the external conductor 5 which is a conductive writing instrument such as a pencil in contact with or close to the support surface 14 a by the touch sensor 32, the touch sensor 32 detects the external conductor 5 on the support surface 14 a of the external conductor 5. Are continuously detected, and data of the trajectory of the movement of the outer conductor 5 is acquired. For example, when the writing sheet 1 is placed on the support surface 14 a of the detection means 30 and characters or figures are written on the writing sheet 1 with the writing tool (external conductor) 5, the movement path of the writing tool 5 with the touch sensor 32. Get the data. When the writing board 11 is connected to the display device, the data written on the writing sheet 1 by the writing tool 5 is transmitted by transmitting the movement locus data of the writing tool 5 to the display device in real time (real time processing). It is displayed on the display device. Further, data of the locus of movement of the writing instrument 5 may be stored in a storage device such as a flash memory.

  As the writing sheet 1, any insulating sheet such as paper can be used. Commercially available paper can be used. In addition, the whole writing sheet 1 does not need to be insulating, and a part of the writing sheet 1 may have conductivity. In FIG. 6, for ease of viewing, the writing sheet 1 appears away from the support surface 14a in the same manner as the other layers. However, the writing sheet 1 is actually placed in contact with the support surface 14a. Yes.

As the writing instrument 5, a writing instrument having a conductor that can be detected by the touch sensor 32 at or near the leading end that contacts the writing sheet 1 can be used. The touch sensor 32 can detect the conductor provided in the tip part of the writing instrument 5 or in the vicinity of the tip part, and acquire the movement locus of the writing instrument 5.
Here, “near the tip” refers to a range within 5 mm from the tip of the writing instrument. Examples of the writing instrument 5 having a conductor at the tip can include a pencil, a ballpoint pen, a fountain pen, and the like. The pencil has a core made of graphite at the tip, and this core forms a conductor. In other words, since the lead of the pencil and the lead of the mechanical pencil are conductors, writing tools that are normally used by children, students, and students can be used as usual in the educational setting. In a ballpoint pen or fountain pen having a metal member at the tip, this metal member serves as a conductor. As the writing instrument 5 having a conductor in the vicinity of the tip, various writing instruments having a metal member in the vicinity of the tip can be suitably used.

FIG. 7 shows one scene where erasure detection is performed by the writing board 11. At this time, the control means 20 detects that the touch sensor 32 uses the conductive eraser 51 and erases, and continuously positions the conductive eraser 51 as an external conductor on the support surface 14a. And the data of the locus of movement of the conductive eraser 51 is acquired. Then, the character or figure data recorded in advance on the movement locus is deleted. For example, when the writing sheet 1 is placed on the support surface 14 a of the detecting unit 30 and characters or figures drawn on the writing sheet 1 are erased by the conductive eraser 51, the touch eraser 51 of the conductive eraser 51 is removed. Acquire data on the trajectory of movement. Then, the character or graphic data drawn in advance at this position is deleted.
When the writing board 11 is connected to the display device, the data on the locus of movement of the conductive eraser 51 is transmitted to the display device in real time (real-time processing), so that the conductive eraser 51 transmits the data to the writing sheet 1. The written content is erased and displayed on the display device. Further, data of the locus of movement of the conductive eraser 51 may be stored in a storage device such as a flash memory.

  As can be seen from the above, it is determined that a character or figure has been drawn by writing using a pencil or the like, and the above-mentioned writing data is created, or by using a conductive eraser, It is determined that the figure has been erased, and it is necessary to select whether to erase the character or figure data at that location. In this embodiment, this determination is made automatically without any separate operation by the user. Details are as follows.

  Since both writing and erasing are detected by the touch sensor 32, it is determined by the program whether writing or erasing is performed from the touch sensor 32 according to the detection mode. More specifically, the length, area, and trajectory of the input data are statistically analyzed, and a threshold is set in advance to determine whether writing has been performed or erasure has been performed. To do. As a more specific example, it can be determined as follows.

  Normally, when drawing a character, the pencil is removed from the paper one by one and moved to the next place. On the other hand, when erasing, after inputting a certain area or more with a pencil, after a momentary time lag of switching to a conductive eraser, the conductive eraser is continuously moved while being pressed against the paper surface. Accordingly, the locus detected by the touch sensor 32 is longer erased than writing, and it can be determined that the locus has been erased when the locus exceeds a certain threshold.

  Further, as shown in FIG. 8, erasing is generally performed because the erased area VIIIb is generally smaller than the entire written area VIIIa, as shown in FIG. be able to.

Alternatively, during the erase operation of the conductive eraser, the range of movement of the conductive eraser is limited to the vicinity of the erroneous input range of the pencil. There are individual differences, the range of motion of the conductive eraser is ^{1cm 2 ~9cm} 2 about. The upper and lower limits of the area in which the conductive eraser moves is set as a threshold value, and if it falls within that range, it can be determined as a conductive eraser.

  Further, the conductive eraser, pencil, and hand have different electrical conductivities. It is also possible to detect that the erase has been performed by detecting the difference in capacitance distribution obtained from these differences and comparing it with a threshold value.

  In addition, the writing is drawn with a trajectory having a predetermined meaning in nature, whereas the trajectory due to the conductive eraser is often repeatedly zigzag-reciprocated as indicated by IX in FIG. It can be determined that erasure has been performed according to such a trajectory mode.

  The determination criteria as described above may be determined by one, or may be determined by applying a plurality of combinations in order to obtain higher accuracy.

The calculation and the control of each member based on the result are performed by the control means 20. That is, according to the writing board system 10, the final result of writing can be converted into data using a general-purpose pencil and the conductive eraser 51 described above. If erasing is performed with a conductive eraser during the writing process, the erasing can be detected and appropriately reflected in the data. And if you draw letters and figures again with a pencil, it will be reflected.
Then, the writing board 11 automatically performs such discrimination of the use of the pencil and the use of the conductive eraser without depending on the user. Therefore, the user only has to write in the same way as normal writing, and there is no need for an additional operation by using the writing board system 10, which is highly convenient.

Such a writing board system 10 can be used in various situations, but is particularly effective in educational applications, for example. In the education field, drawing of characters and figures with a pencil and erasure of errors with an eraser are still common. According to the present invention, for example, in the preparation of answers on paper such as a collection of questions, children, students, and students (sometimes referred to as “children”) may normally prepare an answer with a pencil and a conductive eraser. , Can reduce the burden. Therefore, since the children need only visually recognize the information with characters and figures appearing on the paper, there is no sense of incongruity.
Then, the content written on the paper by the student on the support surface 14a of the writing board 11 can be displayed on a display device such as a screen or a display. By displaying each student's answer to a paper-printed assignment (exam) on the teacher's display, you can monitor the progress of each student's assignment and score in real time as the assignment progresses. It becomes possible to do.

1 Written sheet 5 External conductor (writing instrument)
DESCRIPTION OF SYMBOLS 10 Writing board system 11 Writing board 12 Case 13 Control part 14 Detection part 14a Support surface 20 Control means 30 Detection means 31 Surface layer board 32 Touch sensor 33 Support film 34 1st electrode (detection electrode)
35 Second electrode (detection electrode)
40 Shielding film 41 Reinforcing plate 51 Conductive eraser

Claims (2)

A conductive eraser used for a writing boat having a projected capacitive coupling type touch center,
A resin capable of erasing the written content written on the writing sheet with a writing instrument having a core containing graphite;
Conductive particles contained in an amount that can be detected by the touch sensor with respect to the resin,
Conductive eraser.   The conductive eraser according to claim 1, wherein the conductive fine particles contain a carbon material.