Wireless display systems, styli, and associated methods

• US 6,717,073 B2
• Filed: 12/29/2000
• Issued: 04/06/2004
• Est. Priority Date: 12/29/2000
• Status: Expired due to Term

• Current Assignee: Beijing Xiaomi Mobile Software Co., Ltd. (Xiaomi Corp.)
• Original Assignee: Intel Corporation
• Inventors: Xu, Jianping, Hunt, Stephen H.
• Primary Examiner(s): Awad, Amr Ahmed
• Application Number:
  US09/751,048
• Publication Number:
  US 20020084114A1
• Time in Patent Office: 1,194 Days
• Field of Search: 345/173-180, 345/156, 178/18.01, 178/18.02, 178/18.03, 178/18.04, 178/19.01, 178/19.02, 178/19.07
• US Class Current: 178/18.04
• 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 wireless coordinate input system for a display system includes a stylus that transmits ultrasonic energy to a plurality of ultrasonic receiving stations in a projection plane. The stylus may include one ultrasonic transmitter used for determination of three-dimensional coordinates of the stylus relative to the projection plane. The stylus may also include a second ultrasonic transmitter controlled by a pressure-activated switch. When the stylus is pressed against the projection plane, the second transmitter turns on and is used for determination of two-dimensional coordinates of the stylus in the projection plane. The stylus may also include a higher frequency burst transmitter used to generate a time reference. One or more of the ultrasonic receiving stations may also include an ultrasonic transmitter for calibration.

Claims

1. A method of operating an ultrasonic coordinate input system comprising:

transmitting a burst of ultrasonic energy from an ultrasonic transmitter in a projection plane;

receiving the burst of ultrasonic energy at a receiver an unknown distance away from the ultrasonic transmitter in the projection plane;

determining the unknown distance from a propagation time of the ultrasonic energy;

receiving at the receiver a higher frequency burst signal from a stylus;

receiving at the receiver ultrasonic signals from the stylus;

receiving at an additional receiver in the projection plane ultrasonic signals from the stylus;

triangulating the position of the stylus relative to the projection plane; and

when the ultrasonic signals from the stylus are at a first frequency, triangulating in two dimensions; and

when the ultrasonic signals from the stylus are at a second frequency, triangulating in three dimensions.

2. The method recited in claim 1, wherein the higher frequency burst signal comprises a radio frequency signal.

3. The method recited in claim 1, wherein the transmitter and the additional receiver are co-located.

4. A method comprising:

transmitting a burst of ultrasonic energy from an ultrasonic transmitter in a projection plane;

receiving the burst of ultrasonic energy at a first receiver an unknown distance away from the ultrasonic transmitter in the projection plane;

determining the unknown distance from a propagation time of the ultrasonic energy;

receiving at the first receiver ultrasonic signals from a stylus;

receiving at two additional receivers in the projection plane ultrasonic signals from the stylus;

triangulating the position of the stylus relative to the projection plane; and

when the ultrasonic signals from the stylus are at a first frequency, triangulating in two dimensions, using two of the receivers; and

when the ultrasonic signals from the stylus are at a second frequency, triangulating in three dimensions, using three of the receivers.

5. The method recited in claim 4, wherein the transmitter and one of the additional receivers are co-located.

6. The method recited in claim 4, and further comprising:

receiving at the first receiver a higher frequency burst signal from the stylus; and

using the higher frequency burst signal as a time reference for at least one of the receivers.

7. A method comprising:

receiving at a first receiver in a projection plane of a projection system ultrasonic signals from a stylus;

receiving at two additional receivers in the projection plane ultrasonic signals from the stylus;

triangulating the position of the stylus relative to the projection plane;

when the ultrasonic signals from the stylus are at a first frequency, triangulating in two dimensions; and

when the ultrasonic signals from the stylus are at a second frequency, triangulating in three dimensions; and

receiving at the first receiver a higher frequency burst signal from the stylus; and

using the higher frequency burst signal as a time reference for at least one of the receivers.

8. The method recited in claim 7, and further comprising:

one of the additional receivers receiving ultrasonic signals from a transmitter co-located with the other of the additional receivers.

9. The method recited in claim 7, wherein the higher frequency burst signal comprises a radio frequency signal.