Trackball having single emitter-detector detecting chopper wheel direction

• US 5,644,337 A
• Filed: 06/06/1995
• Issued: 07/01/1997
• Est. Priority Date: 06/06/1995
• Status: Expired due to Fees

• Current Assignee: Zenith Electronics Corporation (LG Corporation)
• Original Assignee: Zenith Electronics Corporation (LG Corporation)
• Inventors: Stacy, Carl W.
• Primary Examiner(s): Powell, Mark R.
• Application Number:
  US08/467,424
• Time in Patent Office: 756 Days
• Field of Search: 345/166, 345/165, 345/164, 345/163, 345/167, 356/446, 250/227.21, 250/233
• US Class Current: 345/167
• CPC Class Codes: G06F 3/0312 for tracking the rotation of a spherical or circular member, e.g. optical rotary encoders used in mice or trackballs using a tracking ball or in mouse scroll wheels tracking relative movement in co-operation with a regularly or irregularly patterned surface, e.g. as in optical mice G06F3/0317; constructional details of scroll or thumb-wheels G06F3/0362; optical rotary encoders G01D5/3473
• CPC Class Codes: G06F 3/03549 Trackballs G06F3/03541 takes precedence

Abstract

A simplified trackball arrangement utilizes a single IR emitter-detector combination for determining the distance and direction of movement of a chopper wheel. The chopper wheel has a plurality of slots for interrupting the infrared path between the emitter-detector combination. The distance travelled by the trackball is a function of the number of slots interrupting the emitter-detector combination IR path. The slots are arranged in a distinctive 1-2-3 pattern such that the direction of rotation may be determined by a pattern detector sensing a 1-2-3 or a 3-2-1 pattern to the IR beam interruptions.

Claims

1. In combination:

a trackball;

a chopper wheel arranged in a driving relationship with said trackball;

a directional slot pattern on said chopper wheel;

an IR emitter-detector sensing movement of said chopper wheel; and

pattern detection means responsive to said directional slot pattern for determining the direction of movement of said chopper wheel.

2. The combination of claim 1 wherein said chopper wheel has a distinctive sequence of slots for distinguishing between clockwise and counterclockwise rotation of said chopper wheel.

3. The combination of claim 2 wherein said distinctive sequence comprises spaced groupings of different numbers of said slots.

4. The combination of claim 3 wherein said spaced grouping form a distinctive 3, 2, 1 slot pattern for one direction of movement of the chopper wheel and a 1, 2, 3 pattern for the opposite direction of movement.

5. In combination:

a trackball;

a pair of chopper wheels arranged in a driving relationship with said trackball;

a distinctive slot pattern comprising spaced groupings of different numbers of slots on each of said chopper wheels;

two-emitter-detector combinations for sensing movements of said chopper wheels, respectively; and

pattern detection means responsive to said spaced groupings of different numbers of slots for determining the direction of said movements of said chopper wheels.

6. The combination of claim 5 wherein said spaced groupings form a 3, 2, 1 pattern for one direction of chopper wheel movement and a 1, 2, 3 pattern for the opposite direction of chopper wheel movement.

7. A trackball mechanism for producing a directional output based upon rotational movement of a trackball comprising:

a trackball mounted for rotational movement;

a pair of X and Y rollers drivingly engaging said trackball;

a pair of chopper wheels respectively driven by said X and Y rollers;

an emitter-detector combination positioned with respect to each of said chopper wheels for detecting movement thereof, said chopper wheels each having a distinctive pattern comprising a sequence of a plurality of slots for making and breaking the infrared paths between said emitter-detector combinations responsive to movement of said chopper wheels;

distance detection means for determining the distance traveled by said trackball based upon slot movement between said emitter-detector combinations; and

pattern detection means coupled to said distance detection means for determining the rotational direction of movement of said chopper wheels based from said distinctive pattern of said slots.