DIRECTIONAL ULTRASOUND TRANSMITTING STYLUS

• US 20140225875A1
• Filed: 01/10/2014
• Published: 08/14/2014
• Est. Priority Date: 07/12/2011
• Status: Active Grant

• Current Assignee: Pnf Co., Ltd.
• Original Assignee: Luidia Incorporated (Luidia Global Co., Ltd.)
• Inventors: Ding, Yao, Harel, Jacob
• Granted Patent: US 9,304,611 B2
• Time in Patent Office: Days
• US Class Current: 345/179
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/0433 in which the acoustic waves are either generated by a movable member and propagated within a surface layer or propagated within a surface layer and captured by a movable member

Abstract

A stylus that includes a tip portion that has a cavity. The cavity has a plurality of holes at a first end and a transmitter of acoustic, e.g., ultrasound waves at the end longitudinally opposite the first end. The tip portion has a tip. The tip end is less than a quarter of a wavelength from the exit ends of the holes. When the end of the tip is placed against a working surface, the acoustic waves travel from the transmitter through the cavity, exit the holes and travel less than a quarter of a wavelength to the working surface relatively close to the tip.

Claims

1. A stylus comprising:

a housing elongated along a longitudinal axis, and including a body portion and a tip portion at one end of the housing, the tip portion being attached to or integral with the body portion;

a tip at the tip portion for pointing at a working surface, the tip having an end for placing on the working surface;

a cavity extending longitudinally including a plurality of holes at a first end closest to the tip and a second end longitudinally opposite the first end;

a transmitter of acoustic waves located at the second end of the cavity and configured to transmit acoustic waves at a main wavelength within the cavity towards that first end having the holes, the holes having exits from the cavity through which the acoustic waves can travel towards the end of the tip; and

electronics to drive the transmitter of acoustic waves, including a power source for the electronics;

wherein the acoustic transmitter is arranged such that when driven by the electronics, and the end of the tip is in contact with the working surface, acoustic waves emanate from the front emitting surface of the acoustic transducer towards holes in the cavity, and out of the ports towards the end of the tip,

wherein the distance between the exit of the ports and the end of the tip is less than a quarter of the main wavelength, and

wherein the acoustic waves are detectible by a plurality of acoustic sensors, the acoustic waves detected by the sensors being usable to determine the location of the end of the tip on the working surface.

2. A stylus as recited in claim 1, wherein the transmitter of acoustic waves has a front emitting surface forming the second end of the cavity.

3. A stylus as recited in claim 2, further comprising a transmitter of electromagnetic signals.

4. A stylus as recited in claim 1, wherein the cavity is formed in the tip portion.

5. A stylus as recited in claim 4, wherein the cavity has a length in the longitudinal direction of an integral number of half the main wavelength.

6. A stylus as recited in claim 5, wherein the length of the cavity in the longitudinal direction is one main wavelength.

7. A stylus as recited in claim 1, wherein the transmitter is configured to transmit ultrasound.

8. A stylus as recited in claim 7, wherein the ultrasound has a main frequency of 40 kHz.

9. A stylus as recited in claim 1, wherein the holes surround the longitudinal axis.

10. A stylus as recited in claim 1, wherein the transmitter is configured to transmit ultrasound, and wherein there are 6 holes surrounding the longitudinal axis uniformly spread along a circle of diameter less than half the main wavelength.

11. A stylus as recited in claim 1, further comprising a switch mechanically coupled to the tip such that when the end of the tip is pressed against the working surface, the switch activates the electronics to cause acoustic waves to emanate from the front emitting surface of the acoustic transducer towards holes in the cavity, and out of the ports towards the end of the tip.

12. A stylus as recited in claim 1, further comprising a transmitter of electromagnetic radiation, and electronics, coupled to the power source and to the transmitter of electromagnetic radiation, and operative to drive the transmitter of electromagnetic radiation, wherein the switch is further arranged such that when the end of the tip is pressed against the working surface, the switch activates the electronics to drive the transmitter of electromagnetic radiation to cause pulses of a electromagnetic radiation to emanate from the stylus.