JP2005165956A - Method for detecting position of electronic pen, electronic pen and electronic blackboard system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for accurately detecting the position of an electronic pen even when any infrared pulse from an infrared generating part on the top end of an electronic pen does not reach the infrared receiving part of a signal processor mounted on a screen. <P>SOLUTION: An infrared generating part 33 is arranged at any part other than the pen top of an electronic pen 3, and an infrared pulse transmitted from the infrared generating part 33 is also used for the position detection of the electronic pen 3. In this case, it is possible to ignore most of the influence of the deviation of the positions of the two infrared generating parts 32 and 33 on the position detection of the electronic pen 3. Thus, it is possible to accurately detect the position of the electronic pen 3 even when the infrared pulse from the infrared generating part 32 of the electronic pen 3 does not reach the infrared receiving part of a signal processor mounted on a screen. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electronic pen.

  In recent years, electronic blackboards have been used in various presentations. In a presentation using an electronic blackboard, a projector first projects a format image created in advance on a screen. Then, the presenter adds an electronic pen to the format image projected on the screen.

  In such an electronic blackboard, in order to synthesize a format image projected on a screen and a retouched image by an electronic pen, a light emitting unit and / or an ultrasonic wave generating unit are provided on the electronic pen, and light and / or on the projector or screen Alternatively, it is necessary to provide an ultrasonic detection unit so that the projector or the screen can detect the position of the electronic pen.

For example, an electronic pen position detection method disclosed in Japanese Patent Application Laid-Open No. 2002-333314 (Patent Document 1) or the like uses a signal processing apparatus having two ultrasonic receivers and one infrared receiver as a screen. The two ultrasonic receivers and one infrared receiver receive the infrared pulse and the ultrasonic pulse transmitted from the electronic pen having the infrared generator and the ultrasonic generator. The position of the electronic pen is detected. Specifically, using the principle of knowing the distance to lightning in the time from when the lightning is seen until the sound is heard, two ultrasonic waves are input after the infrared light pulse is input to the infrared light receiving unit. The distance from the electronic pen to the two ultrasonic receivers is determined by measuring the time until the ultrasonic pulse is input to the receiver. The position of the electronic pen is obtained from the principle of triangulation.
JP 2002-333314 A

  In general, an electronic pen has an infrared light generator at the tip. This is because the purpose is to detect the position of the pen tip. However, depending on how to hold the electronic pen, the infrared light generation unit may be hidden, and the infrared light pulse may not reach the infrared light reception unit of the signal processing device, which may make it difficult to detect the position of the electronic pen.

  The object of the present invention is to reliably position the electronic pen even when the infrared light pulse from the infrared light generator at the tip of the electronic pen does not reach the infrared light receiver of the signal processing device attached to the screen. It is to provide a method capable of detection.

  In order to achieve the above object, the present invention provides an infrared light generation unit in addition to the pen tip of the electronic pen, and an infrared light pulse transmitted from the infrared light generation unit is also used for detecting the position of the electronic pen. . Although the positions of the two infrared light generators are misaligned, the influence on the position detection of the electronic pen is almost negligible, so the infrared light pulse from the infrared light generator at the tip of the electronic pen is applied to the screen. Even when it does not reach the infrared light receiver of the attached signal processing device, the position of the electronic pen can be detected reliably.

  As described above, according to the present invention, the infrared light pulse from the infrared light generation unit at the tip of the electronic pen is blocked by the presenter's hand, for example, of the signal processing device attached to the screen. Even when it does not reach the infrared light receiver, the position of the electronic pen can be detected reliably.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  Referring to FIG. 1A, an electronic pen 3 according to an embodiment of the present invention includes an ultrasonic wave generator 31, an infrared light generator (pen tip) 32, and an infrared light generator (pen rear end). 33, a sound generation control unit 34, and a light emission control unit 35.

  On the other hand, referring to FIG. 1B, the conventional electronic pen 3 includes an ultrasonic wave generation unit 31, an infrared light generation unit (pen tip) 32, a sound generation control unit 34, and a light emission control unit 35. .

  The electronic pen 3 according to the embodiment of the present invention is different from the electronic pen 3 of the prior art in that an infrared light generation unit 33 is added to the rear end of the electronic pen 3. Both the infrared light generation part (pen tip) 32 and the infrared light generation part (pen rear end) 33 are controlled by the light emission control part 35 and blink simultaneously.

  When the electronic pen 3 is pressed against the screen, the sound generation control unit 34 and the light emission control unit 35 include an ultrasonic wave generation unit 31, an infrared light generation unit (pen tip) 32, and an infrared light generation unit (pen rear end). 33 are respectively controlled to simultaneously generate an ultrasonic pulse and an infrared light pulse (here, a pulse means a signal output only for a moment).

  As described above, the electronic pen 3 has infrared light generators (32, 33) at two locations, the pen tip and the pen rear end. Therefore, for example, even if the infrared light pulse transmitted by the infrared light generation unit 32 at the pen tip is blocked by the presenter's hand, the infrared light generation unit 33 at the rear end of the pen is not blocked. The infrared light pulse transmitted from the infrared light generator 33 at the rear end can be used for position detection of the electronic pen 3.

  Next, a method for detecting the position of the electronic pen 3 using an infrared light pulse and an ultrasonic pulse in the electronic blackboard system will be described with reference to FIG.

  The signal processing device 2 attached to the screen 1 is provided with an infrared light receiving unit 20 and ultrasonic receiving units 21 and 22. An infrared light pulse and an ultrasonic pulse are simultaneously output from the electronic pen 3 (note that the infrared light pulse is simultaneously output from both the infrared light generation units 32 and 33).

  The signal processing device 2 uses the principle that the distance to the lightning can be determined by the time from when the lightning light is seen until the sound is heard, and after the infrared light pulse is input to the infrared light receiving unit 20, the ultrasonic wave is received. The distance from the electronic pen 3 to the ultrasonic receivers 21 and 22 can be determined by measuring the time until the ultrasonic pulses are input to the receivers 21 and 22, respectively.

  Since the ultrasonic light receivers 21 and 22 are fixed to the signal processing device 2, the position of the electronic pen 3 can be obtained from the principle of triangulation (if the distance from two different points to a certain point is known). The position of the point can be calculated).

  Next, to what extent is the position of the electronic pen 3 obtained from the infrared light pulse from the infrared light generation unit 32 and the position of the electronic pen 3 obtained from the infrared light pulse from the infrared light generation unit 33. Consider whether it is off.

  For example, it is assumed that the distance between the infrared light generator 32 and the infrared light generator 33 is 20 cm (0.2 m). In this case, the time lag when the infrared light pulses transmitted from the infrared light generator 32 and the infrared light generator 33 reach the infrared light receiver 21 is approximately 0.2 [m] / 300,000,000. [m / s] = 0.6 [ns].

  On the other hand, since the processing speed at which the ultrasonic receivers 21 and 22 detect the ultrasonic pulse is on the order of μs, even if a time difference occurs in the arrival of the infrared light pulse on the order of ns, it is almost at the detected position. It can be said that there is no effect.

  From the above, it can be said that the infrared light generation part in the electronic pen is no problem anywhere on the electronic pen.

(A) is the figure which showed the structure of the electronic pen of one Embodiment of this invention, (b) is the figure which showed the structure of the electronic pen of a prior art. It is the figure which showed the mode of the position detection of an electronic pen.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Screen 2 Signal processing apparatus 20 Infrared light receiving part 21 Ultrasonic receiving part 22 Ultrasonic receiving part 3 Electronic pen 31 Ultrasonic wave generating part 32 Infrared light generating part (pen tip)
33 Infrared light generator (rear end of pen)
34 Pronunciation control part 35 Light emission control part

Claims (4)

Method for detecting position of electronic pen having infrared light generation unit and ultrasonic wave generation unit by signal processing device provided on screen of electronic blackboard system and having infrared light reception unit and plural ultrasonic reception units In
A method of providing a plurality of the infrared light generation units at different positions of the electronic pen. In an electronic pen that is used in an electronic blackboard system and has an infrared light generation unit and an ultrasonic generation unit that generate an infrared light pulse and an ultrasonic pulse, respectively, at the tip in order to detect its position,
In addition to the infrared light generation unit, a second infrared light generation unit that similarly uses the position detection and generates a second infrared light pulse synchronized with the infrared light pulse. An electronic pen.   The electronic pen according to claim 2, wherein the second infrared light generation unit is provided at a rear end of the electronic pen. The electronic pen according to claim 2 or 3,
An infrared light receiver and a plurality of ultrasonic receivers, the position of the electronic pen, the infrared light receiver receives infrared light pulses from the infrared light generator, An electronic blackboard system comprising: a screen device provided with a signal processing device that detects by using time until an ultrasonic wave reception unit receives an ultrasonic pulse transmitted simultaneously with the infrared light pulse from the ultrasonic wave generation unit. .

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