CN104067203B - Electronic pen - Google Patents

Abstract

The invention provides an electronic pen, which can immediately reflect the trace written by the electronic pen on the screen, so that the user has a good writing feeling. An electronic pen that outputs information about the writing position, including: a light emitting element that emits light of a specific wavelength band; a pen tip that emits light to the writing surface of the electronic pen; a sensor that outputs information indicating whether the pen tip is in contact with the writing surface ; the control unit that detects whether the tip of the pen is in contact with the surface to be written based on the information output by the sensor; and the holding mechanism that keeps the pressure applied to the sensor constant by the elastic force of the elastic body, and the control unit controls the pressure that the sensor maintains from the holding mechanism When released, it is determined that the tip of the pen is in contact with the surface to be written.

Description

electronic pen

technical field

The present invention relates to electronic pens.

Background technique

In recent years, display devices having an interactive function in which a presenter can add information such as figures and characters to an original image displayed on an electronic blackboard or the like have begun to be used in exhibition sites. When this electronic blackboard (interactive whiteboard) and a projector are installed together, the projector projects a pre-made format image on the screen, and then the user modifies the format image.

In this electronic blackboard, in order to combine the format image projected on the screen with the image modified by the electronic pen, it is necessary to install a light emitting part or an ultrasonic wave generating part in the electronic pen, and to install light or ultrasonic waves or both on the projector body or the screen. The detection unit detects the position information of the electronic pen.

Here, as a method of detecting the position of the electronic pen, for example, a super wide-angle lens and a semiconductor imaging element are combined as a single infrared light receiving unit, and the image on the screen is imported as image data, and the format image created in advance through subsequent calculation processing is used. The position of the electronic pen is detected by comparison (refer to Patent Document 1).

prior art literature

patent documents

Patent Document 1: Japanese Unexamined Patent Publication No. 2011-059768

Contents of the invention

The problem to be solved by the invention

According to Patent Document 1, since the trace written with the electronic pen cannot be immediately reflected on the screen, there is a problem that the writing comfort for the user is poor.

Therefore, the object of the present invention is to provide an electronic pen in which the trace written by the electronic pen can be immediately reflected on the screen.

Technical means for solving problems

In order to solve the above-mentioned problems, one of preferable aspects of the present invention is as follows.

The electronic pen that outputs information about the writing position includes: a light emitting element that emits light of a specific wavelength band; a pen tip that emits light to the writing surface of the electronic pen; and a sensor that outputs information indicating whether the pen tip is in contact with the writing surface ; Based on the information output by the sensor, the control part that detects whether the front end of the pen is in contact with the surface to be written; and the holding mechanism that keeps the pressure applied to the sensor constant by the elastic force of the elastic body, and the control part is when the sensor is held by the holding mechanism. When the pressure is released, it is judged that the tip of the pen is in contact with the surface to be written.

Invention effect

According to the present invention, it is possible to provide an electronic pen in which traces written with the electronic pen can be immediately reflected on the screen.

Description of drawings

Figure 1 is a system structure diagram.

Fig. 2 is an external view of the electronic pen.

Fig. 3 is an exploded perspective view of the entire electronic pen.

Fig. 4 is an exploded perspective view of the interior of the electronic pen.

Fig. 5 is a cross-sectional view of the electronic pen.

Fig. 6 is a detailed exploded perspective view of the interior of the electronic pen.

Fig. 7 is an internal structure diagram of the electronic pen.

FIG. 8 is a diagram showing an arrangement example of pressure-sensitive sensors.

FIG. 9 is a diagram showing a control circuit of the electronic pen.

Fig. 10 is a characteristic diagram showing the light emission distribution of the light emitting element.

Fig. 11 is a characteristic diagram of the pressure sensitive sensor.

FIG. 12 is a diagram showing a projection-type image display device of the mirror-folding type.

FIG. 13 is a diagram showing a mirror-folding type projection image display device.

FIG. 14 is a diagram showing a front projection type image display device.

FIG. 15 is a diagram showing a front projection type image display device.

Symbol Description

1...electronic pen, 2...end, 21...hook, 31...upper housing, 32...lower housing, 31a...recess, 33...external switch, 34...display LED, 4...cap, 5...the front end of the pen, 51...the nib holder, 52...the nib

detailed description

Embodiments are described below with reference to the drawings.

Figure 1 is a system structure diagram. This system consists of a projection-type image display device (projector) 131, a light-receiving part (combination of a super wide-angle lens and a semiconductor imaging element) 134 provided on the projection-type image display device 131 to receive light of a specific wavelength band, and a writing surface (whiteboard or A screen such as an electronic blackboard) 129, and an electronic pen 1 constitute. Here, the state of drawing the line 130 with the electronic pen 1 is shown.

In this embodiment, it is assumed that the light of a specific wavelength band is infrared light for illustration. The electronic pen 1 emits infrared rays from the pen tip when the user writes. The light receiving unit 134 recognizes a track simulated by the user with the electronic pen 1 by receiving infrared rays emitted from the electronic pen 1 . The light receiving unit 134 imports the infrared rays emitted from the electronic pen 1 and the position where the infrared rays are emitted as position information (image data) of the electronic pen 1 and sends them to the drawing device.

When the rendering device receives this image data from the light receiving unit 134, it compares it with a pre-created format image and performs arithmetic processing. That is, based on the locus of the emitting position (writing position) where infrared rays are emitted by the electronic pen 1 , image data on the recognized locus is generated, and the image on the locus is superimposed on the original image. Then, the superimposed image data is sent to the projection-type image display device 131 . The projection-type image display device 131 projects the received image on the screen 129 . As a result, the trace written with the electronic pen is displayed on the screen 129 .

The rendering device may be built in the projection-type image display device 131 , or may be a PC (Personal Computer) connected to the device 131 .

Next, the structure of the electronic pen 1 will be described. 2 is an external view of the electronic pen ((A) is the overall appearance, (B) is a view viewed from the tip of the pen), FIG. 3 is an exploded perspective view of the entire electronic pen, and FIG. 4 is an exploded perspective view of the interior of the electronic pen.

Electronic pen 1 is the shape of the so-called pen used when imitating writing, and its appearance includes: pen front end portion 5 (pen point holding portion 51, pen point 52), holding portion (cover) 4 of pen front end portion 5, upper frame body 31, lower portion The frame body 32, the recessed part 31a, the external switch 33, the display LED34, the hook 21, and the pen tail 2 are comprised.

The pen tip 5 is formed by inserting the pen tip 52 into the pen tip holding portion 51 and is fixedly held by the cover 4 . The cap 4 cushions the pen pressure received by the pen tip 5 in a direction parallel to the writing surface 129 . The upper frame body 31 and the lower frame body 32 are parts constituting a part of the outer package of the electronic pen 1, and have a substantially cylindrical shape divided into two parts along an imaginary axis Ax passing through the center of the electronic pen 1. Open-ended container shape. In addition, several fixing ribs 321 are provided on the inner wall surface in order to fix the components inside the housing.

The recessed part 31a is provided in the grip part in order to improve the grip feeling of the thumb and forefinger when writing, and to prevent rolling due to force majeure or the like when placed on a table.

The upper frame 31 is superimposed on the lower frame 32 in which the above components are accommodated, and the male screw provided at one end is mechanically coupled with the female screw provided on the inner surface of the cover 4 . The other end is mechanically joined by press-fitting the tail 2 provided with the hook 21 .

The light-emitting element 7 is, for example, a light-emitting diode having the directional characteristics (light-scattering characteristics) shown in FIG. 10 . When light-emitting diodes are used, there is an effect that the lifespan is long and the cost can be kept low.

As another light source, there is an infrared laser diode having a small divergence angle and excellent energy-to-light conversion efficiency. In this case, since the laser beam has a small divergence angle and excellent linearity, a member with a high light diffusion effect can be used for the nib holder 52 , but it may also have a directional characteristic in order to increase the infrared light emitted to the light receiving unit 134 .

In addition, the electronic pen 1 incorporates an electric double layer capacitor (EDLC: Electric Double Layer Capacitor) or a dry battery as a power supply to the light emitting element 7 , and is formed in a substantially cylindrical shape. FIG. 5 shows an example in which a control circuit 1011 for controlling charging from an external power source and two power sources 110 and 111 are used as the EDLC 100 .

The electronic pen 1 is composed of a plurality of hollow members arranged along an imaginary axis Ax passing through the center of the pen tip 5 . Inside the electronic pen 1 , the pen tip portion 5 , the light emitting element 7 , and the detection unit 75 are disposed in order from the writing surface 129 .

Fig. 5 is a cross-sectional view of the electronic pen. Here, the light emitting element 7 , the detection unit 75 , the base 76 , and the like are shown exploded in the direction of the virtual axis Ax. The light-emitting element 7 is disposed on the pen tip 5, and is controlled to emit light by a light-emitting element drive circuit (connected to the connector 103 of the light-emitting element 7 through a connector 102 ( FIG. 7(A)) provided on one side of the circuit board 8 . , the pen tip 5 emits infrared light.

The light emitting element 7 is inserted into the first hollow member 71 from the pen tip 5 side, and is fixed by the end surface of the cylindrical support member 713 on the pen tip 5 side. The outer peripheral portion of the support member 713 is equipped with an elastic convex portion 711, and when sliding along the cylindrical inner surface of the second hollow member 74 (consisting of three parts 741, 742, and 743), the convex portion 711 is provided in the same manner as the The hole 7421 on the inner surface of the cylinder is fitted. At this time, one end of the spring member 72 is fixed by a wall surface provided on the cylindrical surface of the second hollow member 74 .

In addition, the other end surface of the first hollow member 71 is divided so as to be substantially parallel to a virtual axis Ax passing through the center of the electronic pen 1 , and a turned-back portion 712 is provided on the outer peripheral portion thereof.

The light-emitting element 7, the first hollow member 71 and the spring member 72 are inserted into a cylindrical second hollow member 74 extending along an imaginary axis Ax passing through the center of the electronic pen 1, and fixed to the second hollow member 74 by a fixing member 73. internal. A through-hole 734 is provided on the bottom surface of the fixing member 73 , and the turned-back portion 712 provided on the outer peripheral portion of the end surface of the first hollow member 71 is engaged with the through-hole 734 to be fixed to the fixing part 73 .

The light emitting element 7 is attached to the pen tip side end of the second hollow member 74 in a state where the lead wire 701 is inserted through the second hollow member 74 . In addition, the lead wire 701 is led out from the other end of the second hollow member 74 and is electrically connected to the light emitting element driving board 102 ( FIG. 7(A) ) through the connectors 102 and 103 .

In the outer peripheral portion of the second hollow member 74, the nib side portion 743 for fixing the light-emitting element 7 is thinner than the central portion 742, and the holding portion 51 for holding the nib 52 is inserted into the nib side portion 743, and the position in the virtual axis Ax direction is determined by the central portion 742. The end face of the portion of the step due to the difference in outer diameter from the nib side portion 743 is determined.

Furthermore, the other end portion of the second hollow member 74 forms a substantially disk-shaped protruding portion 741 protruding in the outer peripheral direction. A notch 7411 recessed toward the axis Ax is formed in a part of the protruding part 741, and the signal cable 751 passes through the notch 7411 and the flat part provided on the cylindrical surface of the fixing member 73, and connects with the pressure sensitive cable provided on the circuit board 8. The pressure-sensitive sensor terminals 104 of the sensor drive substrate 101 are connected. Next, the detection unit 75 for detecting the contact state and the writing pressure when the pen tip 52 contacts the writing surface 129 will be described.

In FIG. 6 , the detecting portion 75 is composed of a base member 76 , a pressure-sensitive sensor fixing member 752 , a signal cable 751 , a first hollow member 71 , a second hollow member 74 , and an extension portion 741 . The base 76 has three pins 761 on its circumference. The pressure sensitive sensor fixing member 752 has three pressure sensitive sensors 753 and three through holes 756 on its circumference. These three through-holes correspond to the above-mentioned three pins, and each pin is fitted in the corresponding through-hole. Accordingly, the position of the pressure-sensitive sensor fixing member 752 can be determined, and a substantially constant (constant) pressure can be applied to the pressure-sensitive sensor 753 .

The pressure sensitive sensor 753 maintains a substantially constant pressure between the pen tip side surface of the protruding portion 741 of the second hollow member 74 and the base member 76 by the elastic force of the spring member 72 disposed on the outer peripheral portion of the first hollow member 71 . .

7 is an internal structure diagram of the electronic pen, (A) shows that the electronic pen 1 is in the OFF state (the pen front end 5 is not in contact with the surface to be written 129), and (B) shows that the electronic pen 1 is in the ON state (the pen front end 5 is not in contact with the surface to be written 129). 5 is in contact with the written surface 129). In the case of (A), a certain pressure is applied to the pressure sensitive sensor 753 , and in the case of (B), no pressure by the spring member 72 is applied to the pressure sensitive sensor 753 .

FIG. 9 is a circuit diagram including a detection circuit 122 that detects an output from a pressure sensitive sensor. The detection circuit 122 is mounted on the light emitting element drive circuit 102 of the circuit board 8 . The CPU (Central Processing Unit) 121 electrically detects whether the electronic pen 1 is in the ON state or the OFF state by comparing the detected value with a preset value (comparing the voltage changes of the plurality of pressure-sensitive sensor terminals 123 ). Specifically, the CPU 121 determines that the electronic pen 1 is in the OFF state when the pressure by the spring member 72 is applied to the pressure-sensitive sensor 753 , and determines that the electronic pen 1 is in the OFF state when the pressure by the spring member 72 is not applied to the pressure-sensitive sensor 753 . It is judged that the electronic pen 1 is in the ON state. That is, a certain pressure is always applied to the pressure sensitive sensor 753, and the ON state of the electronic pen 1 is detected when the pressure disappears. Therefore, compared with the method of detecting the ON state of the electronic pen by applying pressure to the pressure sensitive sensor 753, it can The trajectory of the electronic pen is reflected on the surface to be written faster.

125 represents the power supply of the electronic pen 1. In the inventor's prototype, EDLC is used for weight reduction, and the power supply circuit 120 can be charged from an external power supply, and the power supply fluctuation can be reduced.

FIG. 11(A) is a graph showing characteristics of a resistance-type pressure-sensitive sensor used as a pressure-sensitive sensor in experiments by the inventors, showing changes in resistance value with respect to the horizontal axis (load) in the graph. It was found that when the elastic force of the spring member is selected so as to apply an elastic force of 500 gf or less with a large variation in the resistance value with respect to the load, the ON state and the OFF state of the electronic pen 1 can be clearly detected. Similarly, when the ambient temperature is changed to 0°C, 25°C, or 50°C, since the change in the resistance value of the resistive pressure sensitive sensor relative to (load) has temperature characteristics, it is preferable to apply a region of 500gf or less where the characteristics are relatively stable. The mode of the elastic force selects the elastic force of the spring member.

Fig. 11(B) is a graph showing the results of studying the extent to which the characteristics of the above-mentioned resistive pressure-sensitive sensor recover due to repeated pressurization (here, 10 pressurizations). Even if the same load is applied after 10 pressurizations, the resistance value also decreased. Therefore, it is preferable to have a storage unit that stores the electronic pen 1 in the OFF state when the electronic pen 1 is not used at all (storage), that is, keeps pressing the tip of the electronic pen 1 so that no load is applied to the pressure sensor. This also reduces the reduction in the spring force of the spring member.

On the other hand, when the electronic pen 1 is in the ON state, that is, when the pen tip 5 is in contact with the writing surface 129, the pressure-sensitive sensor 753 detects that the pressure sensor 753 is applied by the elastic force of the spring member 72 arranged on the outer peripheral portion of the first hollow member 71. The pressure between the base member 76 of the part 75 and the pen tip side surface of the protruding part 741 of the second hollow member 74 is released, and the state becomes a no-load state. As a result, the output (resistance value) of the resistive pressure sensitive sensor becomes almost infinite, which is detected by the detection circuit 122 in the same manner as above, and the CPU 121 detects that the electronic pen 1 is in the ON state.

Furthermore, in order to change the thickness of the handwriting information of the electronic pen 1 (thickness of the drawn line) in order to detect the pen pressure, the pen pressure change can be regarded as Large resistance value changes are detected. This is detected by the detection circuit 122 in the same manner as above, and the CPU 121 electrically detects the writing pressure applied to the electronic pen 1 by comparing the detected value with values corresponding to a plurality of preset writing pressures.

Among them, in the above-mentioned embodiment, the case of using three pressure-sensitive sensors was described (FIG. 8(A)), but in order to detect the pen pressure with higher accuracy, or to estimate the moving direction of the pen based on the handwriting of the electronic pen 1 , can also increase the number of pressure-sensitive sensors used. For example, four pressure-sensitive sensors can be arranged equally every 90 degrees in the circumferential direction (Fig. Six pressure-sensitive sensors are arranged at intervals of 60 degrees (Fig. 8(C)).

In the above-mentioned embodiment, the receiving surfaces 311, 321 of the base member 76 and the frame are planes perpendicular to the virtual axis Ax, but it is also possible to make the shapes of the receiving surfaces 311, 321 of the base member 76 and the frame on the opposite side of the pen tip. The side is convex or concave, and the surface of the protruding portion 741 on the nib side is convex or concave accordingly. Thus, by the elastic force of the spring member 72, a substantially constant pressure is maintained between the nib-side surface of the protruding portion 741 and the base member 76. Even if the nib of the electronic pen 1 contacts the surface to be written 129 from an oblique direction, The contact angle exerts a certain pressure on the pressure sensitive sensor.

FIG. 12 is a diagram showing a mirror-folding type projection image display device 131 (hereinafter referred to as a main body) including a mirror 133 for guiding an image to a screen. Here, the state in which the light receiving unit 134 is externally attached to the main body 131 via the fixing belt 135 (the state attached and fixed to the outside of the main body) is shown.

The semiconductor imaging element built-in portion of the light receiving unit 134 has a structure in which an attachment angle can be changed with respect to the main body 131 . In addition, in order to reduce malfunctions, it is preferable to arrange the light receiving unit 132 for receiving light from the remote controller and the light receiving unit 134 for receiving light from the electronic pen 1 on different planes.

FIG. 13 is a diagram showing another form of the mirror-folding type main body 131 . Here, a state in which the light receiving unit 134 is built in the main body 131 is shown. The light receiving unit 134 is arranged near the projection lens (or near the opening and closing portion of the reflecting mirror 133). In addition, in order to reduce malfunctions, it is preferable that the optical axis of the super wide-angle lens of the light receiving unit 134 and the perpendicular line of the optical axis of the light receiving unit 132 of the remote controller be arranged so as to form a predetermined angle.

FIG. 14 is a diagram showing a front projection type image display device 131 . It is the same as that of FIG. 12 except that it is not a mirror return type.

FIG. 15 is a diagram showing another form of the front projection type image display device 131 . It is the same as that of FIG. 13 except that it is not a mirror return type.

As above, according to this embodiment, since a certain pressure is always applied to the pressure sensitive sensor, and the ON state of the electronic pen is detected when the pressure disappears, it is similar to the method of detecting the ON state of the electronic pen by applying pressure to the pressure sensitive sensor. Compared with that, the trajectory of the electronic pen can be reflected on the surface to be written faster. In addition, there is no phenomenon that the amount of deviation between the trace written with the electronic pen and the displayed image of the writing position on the surface to be written differs depending on the screen position. In addition, the thickness of the trace of writing can be immediately reflected on the display image in accordance with the pen pressure when the pen tip comes into contact with the surface to be written on. Furthermore, the moving direction of the electronic pen can be detected immediately from the pen tip and the trace written on the writing surface.

Therefore, it is possible to provide an electronic pen with which a user can write naturally with the same feeling as when writing characters or the like on paper with a generally used writing instrument.

Claims (5)

1. An electronic pen that outputs information about the writing position, is characterized in that, comprising: A light-emitting element that emits light of a specific band; a pen tip that emits the light to a writing surface of the electronic pen; a sensor that outputs information indicating whether the tip of the pen is in contact with the surface to be written; A control unit that detects whether the tip of the pen is in contact with the surface to be written based on the information output by the sensor; a holding mechanism for maintaining a certain pressure applied to the sensor by the elastic force of the elastic body; and a plurality of hollow members extending along an imaginary axis passing through the center of the pen tip, The control unit determines that the tip of the pen is in contact with the writing surface when the sensor is released from the pressure held by the holding mechanism, The first hollow member among the plurality of hollow members is provided with the light-emitting element at one end, with a turned-back portion at the other end, and with a protrusion on the outer wall surface, The elastic body is provided between the protruding portion and the turned-back portion, A second hollow member among the plurality of hollow members includes a cylindrical shaft supporting the first hollow member with a part of an inner wall surface so that the first hollow member does not fall over with respect to the imaginary shaft, and the cylindrical shaft One end of the second hollow member has an inner diameter larger than the outer shape of the first hollow member and smaller than the outer shape of the elastic body. 2. The electronic pen as claimed in claim 1, characterized in that: The pen tip, the light emitting element, and the sensor are arranged in order from the writing surface. 3. The electronic pen according to claim 1 or 2, characterized in that: The light emitting element is a light emitting diode. 4. The electronic pen according to claim 1 or 2, characterized in that: The sensor is a piezoresistive element. 5. A projection type image display device, characterized in that it comprises: The electronic pen according to any one of claims 1 to 4; A light-receiving part including a wide-angle lens and a semiconductor imaging element; A display unit that takes in the locus of the luminous point of the light-emitting element as screen information through the semiconductor imaging element, detects the position of the electronic pen by comparing it with a pre-made format image, and displays the locus of the luminous point Overlaid on the displayed original image.