Coordinate input apparatus, control method therefore, and program

A method of controlling a coordinate input apparatus configured to detect a position pointed on a coordinate input region by using first and second sensor units, each associated with one end of an edge of one side of the coordinate input region, wherein the first and second sensor units each have at least two optical units, wherein the at least two optical units includes a light projecting unit configured to project light onto the coordinate input region and a light receiving unit configured to receive incoming light, comprising:

• a detection step of detecting angle information representing directions of shadows, which are areas light-shielded by pointing performed by two pointing means, according to a light amount distribution, which is obtained from the optical units of the first and second sensor units, on the region including the shadows;
• and
• a calculation step of calculating coordinates of positions pointed to by the two pointing units by using:
• 1) a combination of pieces of angle information on the shadows detected by a combination of the optical units of the different sensor units;
• and
• 2) a combination of pieces of angle information on the shadows detected by a combination of the optical units of a same sensor unit.

A program configured to implement control of a coordinate input apparatus configured to detect a position pointed on a coordinate input region by using first and second sensor units, each associated with one end of an edge of one side of the coordinate input region, wherein the first and second sensor units each have at least two optical units, wherein the at least two optical units includes a light projecting unit configured to project light onto the coordinate input region and a light receiving unit configured to receive incoming light, comprising:

• a program code configured to perform a detection step of detecting angle information representing directions of shadows, which are areas light-shielded by pointing performed by two pointing means, according to a light amount distribution, which is obtained from the optical units of the first and second sensor units, on the region including the shadows;
• and
• a program code configured to perform a calculation step of calculating coordinates of positions pointed by the two pointing means by using:
• 1) a combination of pieces of angle information on the shadows detected by a combination of the optical units of the different sensor units;
• and
• 2) a combination of pieces of angle information on the shadows detected by a combination of the optical units of a same sensor unit.

A coordinate detection device comprising:

• a first pointing means having a first thickness that blocks a portion of incident light forming a first shadow, wherein the first pointing means identifies a first coordinate on a coordinate region;
• a second pointing means having a second thickness that blocks a portion of incident light forming a second shadow, wherein the second pointing means identifies a second coordinate on the coordinate region;
• a first sensor unit, wherein the first sensor unit can distinguish between incident light entering at different angles with respect to the front of the first sensor unit, and wherein the first shadow and second shadow have an associated first shadow first unit angle and second shadow first unit angle detected in the first sensor unit;
• a second sensor unit, wherein the second sensor unit can distinguish between incident light entering at different angles with respect to the front of the second sensor unit, and wherein the first shadow and second shadow have an associated first shadow second unit angle and second shadow second unit angle detected in the second sensor unit;
• and
• a calculation unit that calculates the first and second coordinate based upon the first shadow first unit angle, the first shadow second unit angle, the second shadow first unit angle and the second shadow second unit angle.