Position detection device, position pointing device, position detecting method and pen-down detecting method

A position detection method using a position detection device which comprises:

• a position pointing means having a movable pen-core portion and a light reflection means having a retroreflective member;
• a light emitting means for emitting the light to said light reflection means;
• a light receiving means for receiving the light from said light reflection means of the position pointing means;
• and a coordinate calculation means for calculating a position coordinate of said position pointing means based on information from said light receiving means, said method comprising the steps of:
• emitting light from said light emitting means to the light reflection means of said position pointing means;
• modulating light for changing characteristics of reflection light of said light reflection means based on displacement of said movable pen-core portion produced from the pressure of said position pointing means by an operator onto a coordinate detection surface of said position detection device;
• detecting a pen-down state for obtaining the pen-up and pen-down information of said position pointing means by detecting with said light receiving means characteristics of the light changed by said light modulation means;
• and
• wherein said pen-down state detecting step comprises a step of detecting a pen-down state based on the information of incident angles of light coming from said light reflection means of said position pointing means, said information being received by at least two light receiving means with a predetermined space being provided therebetween.

A pen-down state detection method using a position detection device which comprises:

• a position pointing means having a movable pen-core portion and a light reflection means having a retroreflective member;
• a light emitting means for emitting the light to said light reflection means;
• a light receiving means for receiving the light from said light reflection means;
• of said position pointing means;
• and a coordinate calculating means for calculating a position coordinate of said position pointing means based on information from said light receiving means, said method for detecting as to whether a tip of said movable pen-core portion is in contact with a position coordinate detection surface comprising the steps of:
• emitting light from said light emitting means to the light reflection means of said position pointing means;
• modulating light for changing characteristics of reflection light of said light reflection means based on displacement of said movable pen-core portion produced from the pressure of said position pointing means by an operator onto said position coordinate detection surface of said position detection device;
• detecting a pen-down state for obtaining the pen-up and pen-down information of said position pointing means by detecting with said light receiving means characteristics of the light changed by said light modulation means;
• and
• wherein said pen-down state detecting step comprises a step of detecting a pen-down state based on the information of incident angles of light coming from said light reflection means of said position pointing means, said information being received by at least two light receiving means with a predetermined space being provided therebetween.