Optical imaging pen with displacement detection circuitry

Abstract

Provided is optical imaging pen configured to detect information encoded with infrared ink on a page. The pen includes a housing. An ink pen cartridge and a stylus are mounted side by side in the housing. The ink cartridge and the stylus are configured to be individually brought forward through an open end of the housing by rotation of a pen top rotatably mounted on an end of the housing. The pen also includes an infrared LED inside the housing for providing infrared radiation for projection onto the page, and an image sensor for receiving reflected radiation from the surface. The pen further includes a controller for controlling operation of the LED and sensor, the controller having a force sensor photodiode configured to detect displacement of the stylus to enable a determination of a force being applied to a nib of either the cartridge or stylus. The controller also has analog-to-digital converter circuitry for converting analog signals from the force sensor diode into digital signals capable of encoded transmission.

1 . An optical imaging pen configured to detect information encoded with infrared ink on a page, said pen comprising:
 a housing;   an ink pen cartridge and a stylus mounted side by side in the housing, the ink cartridge and stylus configured to be individually brought forward through an open end of the housing by rotation of a pen top rotatably mounted on an end of the housing;   an infrared LED in the housing for providing infrared radiation for projection onto the page;   an image sensor for receiving reflected radiation from the surface; and   a controller for controlling operation of the LED and sensor, the controller having a force sensor photodiode configured to detect displacement of the stylus to enable a determination of a force being applied to a nib of either the cartridge or stylus, the controller having analog-to-digital converter circuitry for converting analog signals from the force sensor diode into digital signals capable of encoded transmission.   
     
     
         2 . The optical imaging pen of  claim 1 , having a rotatable cam barrel secured to the pen top, the cam barrel including a cam in the form of a slot within walls of the cam barrel for engaging cam followers in the form of projecting slider blocks of the pen cartridge and stylus, wherein rotation of the pen top slides either the pen cartridge or stylus out of the housing. 
     
     
         3 . The optical imaging pen of  claim 1 , which includes a rechargeable battery mounted about, and in contact with, an electronics chassis of the controller with an induction coil mounted about the chassis to enable induction recharging of the battery. 
     
     
         4 . The optical imaging pen of  claim 3 , wherein the force sensor photodiode is configured to detect light from the infrared LED via reflectors mounted on the slider blocks. 
     
     
         5 . The optical imaging pen of  claim 1 , having a radio frequency circuit with a radio frequency (RF) transmitter and receiver and a radio antenna mounted within the housing, said antenna in signal communication with the radio frequency transmitter and receiver. 
     
     
         6 . The optical imaging pen of  claim 1 , wherein the controller includes an orientation sensor which is configured to facilitate calculation of an orientation of the pen. 
     
     
         7 . The optical imaging pen of  claim 1 , having a pair of orthogonal accelerometers mounted in a normal plane of the pen axis, said accelerometers allowing the pen to sense motion.