Touch panel display

• US 5,196,836 A
• Filed: 02/21/1992
• Issued: 03/23/1993
• Est. Priority Date: 06/28/1991
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Williams, Donald D.
• Primary Examiner(s): Brier, Jeffery A.
• Assistant Examiner(s): AU, AMELIA MEGAN
• Application Number:
  US07/839,824
• Time in Patent Office: 396 Days
• Field of Search: 340/712, 340/784, 340/765, 178/18, 250/221, 250/227.22, 250/227.21, 250/229
• US Class Current: 345/175
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

A optical input device which can determine the location of a stylus in a field with only a single emitter and a single detector. A fiber-optic bundle is used to transmit energy from the emitter to the vertical and horizontal output sides of a bezel. The fiber-optic bundle returns energy from the input vertical and horizontal sides of the bezel to the detector. The bezel is covered by LCD masks which block energy transmission through the bezel. A multiplexor scans the LCD masks to allow a beam of energy to scan across the vertical and horizontal fields of the device. The location of a stylus is located by detecting an interrupted beam.

Claims

1. An optical input device for detecting and communicating to a computer the position of a stylus within a predetermined field, said optical input device comprising:

a frame having a first vertical side, a second vertical side, a first horizontal side, and a second horizontal side;

a single energy emitter;

a single energy detector;

a fiber optic bundle having first, and second energy paths, the input of the first energy path connected to the energy emitter and the output of the first energy path connected to the first vertical and horizontal sides of the frame, the input of the

second energy path connected to the energy detector;

a vertical mask between the first and second vertical sides of the frame;

a horizontal mask between the first and second horizontal sides of the frame;

a multiplexor having means to selectively control energy transmission through said vertical and horizontal masks;

whereby the computer determines the location of a stylus by detecting the absence of detected energy when energy transmission is selectively controlled.

2. An optical input device, as recited in claim 1, wherein the multiplexor further comprises:

means to synchronously scan the vertical mask such that only a narrow beam of energy can travel from the first vertical side to the second vertical side at any point in time;

means to synchronously scan the horizontal mask such that only a narrow beam of energy can travel from the first horizontal side to the second horizontal side at any point in time.

3. An optical input device, as recited in claim 2, wherein the multiplexor further comprises:

means to receive control signals from a computer;

means to control selective energy transmission through the vertical mask and the horizontal mask with the control signals received from the computer.

4. An optical input device, as recited in claim 3, wherein the multiplexor further comprises:

means to mask all of the horizontal sides when the vertical mask is scanned, and mask all of the vertical sides when the horizontal mask is scanned.

5. An optical input device, as recited in claim 1, wherein the vertical and horizontal masks are LCD circuits.

6. An optical input device, as recited in claim 5, wherein the vertical and horizontal masks further comprise:

first and second vertical masks attached respectively to the first and second vertical sides of the frame, the masks arranged such that they lie in the path of energy transmitted from the first vertical side of the frame; and

first and second horizontal masks attached respectively to the first and second horizontal sides of the frame, the masks arranged such that they lie in the path of energy transmitted from the first horizontal side of the frame.

7. An optical input device, as recite in claim 6, wherein:

the first and second energy paths are fibers in the fiber optic bundle.

8. An optical input device, as recited in claim 7, wherein:

the first energy path is connected at one end to the energy emitter such that energy from the energy emitter enters the first energy path and travels the length of the first energy path;

the first energy path is connected at the other end to the first horizontal side and the first vertical side such that the first horizontal side and the first vertical side do not obstruct the energy when the energy exits the first energy path;

the fibers in the first energy path further connected such that energy exiting the first energy path is transmitted from a wide area of the first horizontal side and the first vertical side;

the second energy path is connected at one end to the second horizontal side and the second vertical side, the fibers in the second energy path are arranged such that energy received along a wide area of the second horizontal side from the first horizontal side and energy received along a wide area of the second vertical side from the first vertical side enter the second energy path;

the second energy path is connected at the other end to the energy detector such that energy traveling through the second energy path is detected by the energy detector.

9. An optical input device, as recited in claim 8, wherein:

the fibers in the first energy path further connected such that energy exiting the first energy path is transmitted substantially perpendicular to the surfaces of the first horizontal side and the first vertical side, and toward the second horizontal side and the second vertical side respectively.

10. An optical input device, as recited in claim 7, wherein:

the energy emitter produces energy in the infrared range;

the energy detector detects energy in the infrared range.

11. An optical input device for detecting and communicating to a computer the location of a stylus within a predetermined field, comprising:

a frame;

the frame further comprising a first vertical side, a second vertical side, a first horizontal side, and a second horizontal side;

a single energy emitter;

a single energy detector;

a fiber optic bundle;

the fiber optic bundle having a first energy path connected at one end to the energy emitter such that energy from the energy emitter enters the first energy path and travels through the fibers of the energy path;

the first energy path connected at the other end to the first horizontal side and the first vertical side such that the first horizontal side and the first vertical side do not obstruct the energy when the energy exits the first energy path;

the fibers in the first energy path further arranged such that energy exiting the first energy path is transmitted from a wide area of the first horizontal side and the first vertical side substantially perpendicular to the surfaces of the first horizontal side and the first vertical side, and toward the second horizontal side and the second vertical side respectively;

the fiber optic bundle having a second energy path connected at one end to the second horizontal side and the second vertical side, the fibers in the second energy path arranged such that energy received along a wide area of the second horizontal side from the first horizontal side, and energy received along a wide area of the second vertical side from the first vertical side enter the fibers;

the second energy path connected at the other end to the energy detector such that energy traveling through the second energy path is detected by the energy detector;

the energy detector further having means to provide a signal to the computer indicating the presence or absence of energy;

first and second vertical LCD masks attached respectively to the first and second vertical sides of the frame, the masks arranged such that they lie in the path of energy transmitted from the first vertical side to the second vertical side;

first and second horizontal LCD masks attached respectively to the first and second horizontal sides of the frame, the masks arranged such that they lie in the path of energy transmitted from the first horizontal side to the second horizontal side;

a multiplexor having means to receive control signals from the computer;

the multiplexor having means to synchronously scan the first and second vertical LCD masks such that only a narrow beam of energy can travel from the first vertical side to the second vertical side at any point in time;

the multiplexor having means to synchronously scan the first and second horizontal LCD masks such that only a narrow beam of energy can travel from the first horizontal side to the second horizontal side at any point in time;

the multiplexor having means to mask all first and second horizontal LCD masks when the first and second vertical LCD masks are scanned, and mask all first and second vertical LCD masks when the first and second horizontal LCD masks are scanned.

12. An optical input device, as recited in claim 11, wherein:

the energy emitter produces energy in the infrared range;

the energy detector detects energy in the infrared range.

13. A method for detecting and communicating to a computer the location of a stylus within a predetermined field, said method comprising:

emitting energy from a single energy emitter;

guiding energy from said energy emitter through a first energy path comprising fibers in a fiber optic bundle, to first horizontal and fist vertical sides of the predetermined field;

making the first horizontal and first vertical sides of the predetermined field to prevent energy from traveling across the predetermined field to second horizontal and second vertical sides;

multiplexing the mask to selectively control energy transmission through the vertical and horizontal masks;

guiding energy arriving at the second horizontal and second vertical sides through a second energy path comprising fibers in the fiber optic bundle, to a single energy detector;

calculating in the computer the location of a stylus using signals from he energy detector and multiplexor position information.

14. A method, as recited in claim 13, further including the step of:

synchronously scanning the vertical mask such that only a narrow beam of energy can travel from the first horizontal side to the second horizontal side at any point in time.

15. A method, as recited in claim 14, further including the steps of:

receiving control signals from a computer;

controlling the selective energy transmission through the vertical mask and the horizontal mask with the control signals received from the computer.

16. A method, as recited in claim 15, further including the step of:

masking all of the horizontal sides when the vertical mask is scanned, and all of the vertical sides when the horizontal mask is scanned.

17. A system for detecting and communicating to a computer the position of a stylus within a predetermined field, said device comprising:

a computer; and

an optical input device;

further comprising;

a single energy emitter;

a single energy detector having means for outputting a signal to indicate the presence of detected energy;

a frame having a first vertical side, a second vertical side, a first horizontal side, and a second horizontal side, each of the sides capable of conducting energy emitted from the energy emitter;

a fiber optic bundle having first and second energy paths, the first energy path having an input end for receiving energy from the energy emitter and an output end connected to the first vertical and horizontal sides of the frame for outputting the energy through the first vertical and horizontal sides of the frame, the second energy path having an input end connected to the second vertical and horizontal sides of the frame for receiving energy outputted from the first energy path and an output end for outputting energy to the energy detector;

an output mask for blocking energy output from the first energy path;

an input mask for blocking energy from entering the second energy path; and

multiplexor means to selectively control energy transmission from the first sides of the frame to the second sides of the frame by selectively unblocking portions of the output mask and portions of the input mask which are opposed from one another on opposite sides of the frame;

whereby the computer determines the location of a stylus by detecting the absence of energy when said energy mask is selectively unblocked.

18. A system, as recited in claim 17, wherein the multiplexor further comprises:

means to synchronously scan the input mask and the output mask such that only a narrow beam of energy can travel from the first vertical side of the frame to the second vertical side of the frame at any point in time; and

means to synchronously scan the input mask and the output mask such that only a narrow beam of energy can travel from the first horizontal side of the frame to the second horizontal side of the frame at any point in time.

19. A system, such as recited in claim 18, wherein the multiplexor further comprises:

means to mask all of the first and second horizontal sides when the first and second vertical sides are scanned, and mask all of the first and second vertical sides when the first and second horizontal sides are scanned.

20. A system, such as recited in claim 17, wherein the vertical and horizontal masks are LCD circuits.

21. A system, as recited in claim 20, wherein:

the first and second energy paths are fibers in the fiber optic bundle.

22. An optical input device, as recited in claim 21, wherein:

the energy emitter produces energy in the infrared range;

the energy detector detects energy in the infrared range.

23. An optical input device for locating the position of a stylus within a predetermined field, comprising:

a frame for defining a predetermined field, the frame having a first vertical side, a second vertical side, a first horizontal side, and a second horizontal side;

a single energy emitter;

a first group of fiber-optic fibers for distributing energy along the first vertical and first horizontal sides, the fibers in the first group aligned such that energy is transmitted across the predetermined field in the form of a matrix;

a single energy detector;

a second group of fiber-optic fibers for receiving energy along the second vertical and second horizontal sides and connected to the energy detector the fibers in the group aligned such that energy in substantially all of the matrix can be detected;

a scannable mask for blocking energy in the matrix such that only a single beam of energy is allowed to cross from the first horizontal and vertical sides at any point in time;

a multiplexor for controlling the location of the unblocked portion of the scannable mask;

calculating means to determine the location of the intersection of the horizontal and vertical energy beams interrupted by a stylus;

whereby the location of a stylus in a predetermined field can be determined by an optical device with a single emitter and a single detector.