Integrated liquid crystal display and optical touch panel

• US 4,916,308 A
• Filed: 10/17/1988
• Issued: 04/10/1990
• Est. Priority Date: 10/17/1988
• Status: Expired due to Fees

• Current Assignee: Tektronix Incorporated (Fortive Corp.)
• Original Assignee: Tektronix Incorporated (Fortive Corp.)
• Inventors: Meadows, Robert D.
• Primary Examiner(s): Westin, Edward P.
• Application Number:
  US07/258,420
• Time in Patent Office: 540 Days
• Field of Search: 250/221, 250/222.1, 340/712, 340/555, 340/556, 341/31
• US Class Current: 250/221
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

A flat panel liquid crystal display (12) with an integrated touch panel has a multitude of pixels (28) arranged in multiple columns and multiple rows. The pixels (28) of the first column (54) and last column (66), and of the first row (60) and of the last row (72) are controlled in conjunction with emitters (52, 58) and detectors (64, 70) with associated mirrors (74, 80, 82, 84) to create a sequence of light beams that extend across the display panel (12) in both the X and Y directions. Whenever a stylus (86) is placed near the display panel, two orthogonal light beams are interrupted corresponding to the X and Y positions of the stylus (86) relative to the display panel (12).

Claims

1. An integrated display and optical touch panel apparatus, comprising:

(a) a display panel having a plurality of elements arranged in a matrix of multiple columns and multiple rows;

(b) emitter means associated with a first column of elements for projecting light toward those elements, the first column of elements being controllable for assuming a transparent state and an opaque state, the light propagating through any one of the first column of elements that is in the transparent state;

(c) reflection means for directing across the surface of the display panel light propagating through any element in the first column of elements; and

(d) detection means for detecting the light reflected by the reflection means and for providing a signal indicative thereof.

2. The apparatus of claim 1 wherein the detection means includes a second reflection means for redirecting the light reflected by the reflection means toward a second column of elements, the second column of elements being controllable for assuming a transparent state and an opaque state, the light redirected by the second reflection means propagating through an element in the second column whenever that element is in the transparent state.

3. The apparatus of claim 2 wherein the reflection means and second reflection means are mirrors mounted on opposing sides of the panel, the mirrors defining an optical path along which light passing through a first pixel in the transparent state that is in the first column is directed to a second pixel that is in the second column of elements, wherein the first and second pixel are in the same row.

4. The apparatus of claim 1 further including column control means for controlling the first column of elements so that only one element is in a transparent state at any time.

5. The apparatus of claim 1 further including:

second emitter means associated with a first row of elements for projecting light toward those elements, the first row of elements being controllable for assuming a transparent state and an opaque state, the light propagating through any one of the first row of elements that is in the transparent state;

third reflection means for directing across the surface of the display panel light propagating through any element in the first row of elements;

second detection means for detecting the light reflected by the second reflection means and for providing a signal indicative thereof; and

row control means for controlling the first row of elements so that only one element is in a transparent state at any time.