ANALOG DISPLAY USING LIGHT EMITTING DIODES

• US 3,696,393 A
• Filed: 05/10/1971
• Issued: 10/03/1972
• Est. Priority Date: 05/10/1971
• Status: Expired due to Term

• Current Assignee: Thomas W. Mcdonald
• Original Assignee: Thomas W. Mcdonald
• Inventors: McDonald, Thomas W.
• Primary Examiner(s): Trafton, David L.
• Application Number:
  US05/141,890
• Time in Patent Office: 512 Days
• Field of Search: 340/324R,166EL 178/7.3D 315/169TV
• US Class Current: 345/82
• CPC Class Codes: G09G 2300/0885 Pixel comprising a non-linear two-terminal element alone in series with each display pixel element
• CPC Class Codes: G09G 2310/0205 Simultaneous scanning of several lines in flat panels
• CPC Class Codes: G09G 2310/0224 Details of interlacing
• CPC Class Codes: G09G 2310/0254 Control of polarity reversal in general, other than for liquid crystal displays
• CPC Class Codes: G09G 2310/0267 Details of drivers for scan electrodes, other than drivers for liquid crystal, plasma or OLED displays
• CPC Class Codes: G09G 2310/0275 Details of drivers for data electrodes, other than drivers for liquid crystal, plasma or OLED displays, not related to handling digital grey scale data or to communication of data to the pixels by means of a current
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/32 semiconductive, e.g. using light-emitting diodes [LED]
• CPC Class Codes: H04N 3/14 by means of electrically scanned solid-state devices for picture generation H04N25/00

Abstract

A scanned solid state planar display wherein two successive rows are simultaneously energized. Only the latest row energized is written as the columns are driven because the light emitting elements are polarized the same in alternate rows and are oppositely polarized for each suceeding row, and the column generators reverse their driving current polarity for each suceeding row. Interlaced scanning is provided in one embodiment of the invention. Light emitting diodes are used as the display elements. Other light sources with series rectifiers are optionally used.

Claims

1. An analog planar device for displaying a unipolar electrical signal, said device comprising elemental unidirectional conducting light cell units mounted in rows and columns;

an orthogonal set of conductors connected across each of said unidirectionally conducting light cell units at the respective junctions thereof, the light cell units in any row being poled in a common direction and the next succeeding row to be scanned being poled in an opposite direction;

means responsive to said unipolar electrical signal for reversing the polarity thereof commencing with each horizontal scan thereby to provide a bipolar electrical signal;

means for taking successive samples of said bipolar electrical signal during each horizontal scan; and

means for generating currents in proportion to said successive samples and for directing said currents to corresponding light cell units in the row being scanned and the prior row scanned whereby a composite row of light cell units remain energized during presentation of the display.

2. The analog planar device for displaying a unipolar electrical signal as defined in claim 1 wherein said elemental unidirectionally conducting light cell units are light-emitting diodes.

3. The analog planar device for displaying a unipolar electrical signal as defined in claim 1 wherein said elemental unidirectionally conducting light cell units are serially connected light and diode combinations.

4. An analog planar device for displaying a unipolar electrical signal having associated horizontal and vertical synchronizing pulses, said device comprising elemental unidirectionally conducting light cell units mounted in rows and columns;

an orthogonal set of conductors connected across each of said unidirectionally conducting light cell units at the respective junctions thereof, the light cell units in any row being poled in a common direction and the light cells in alternate rows being poled in opposite directions;

means responsive to said horizontal and vertical synchronizing pulses for successively connecting two adjacent row conductors to a terminal maintained at a reference potential level concurrent with each horizontal scan period commencing from the extremities of the display upon the occurrence of each successive vertical synchronizing pulse and moving one row conductor in a non-changing direction upon the occurrence of each successive horizontal synchronizing pulse;

means responsive to said unipolar electrical signal and said horizontal synchronizing pulses for making the polarity thereof commencing with each horizontal synchronizing pulse conform to current flow through said light cells connected to said last row conductor connected to said terminal maintained at said reference potential level thereby to provide a bipolar electrical signal;

means for taking periodic successive samples of said bipolar electrical signal; and

means for generating direct currents in proportion to the amplitude of said successive samples and for directing said currents from the time of said respective samples to corresponding light cell units connected to said last row conductor connected to said terminal maintained at said reference potential level.

5. An analog planar device for displaying a unipolar electrical signal having associated horizontal and vertical synchronizing pulses, said device comprising elemental unidirectionally conducting light cell units mounted in rows and columns;

an orthogonal set of conductors connected across each of said unidirectionally conducting light cell units at the respective junctions thereof, the light cell units in any row being poled in a common direction and the light cells in alternate rows being poled in opposite directions;

means responsive to said horizontal and vertical synchronizing pulses for successively connecting two row conductors spaced one row apart to a terminal maintained at a reference potential level concurrent with each horizontal scan period commencing from alternate adjacent row conductors at the extremities of the display upon the occurrence of each successive vertical synchronizing pulse and moving two row conductors in a non-changing direction upon the occurrence of each successive horizontal synchronizing pulse;

means responsive to said unipolar electrical signal and said horizontal synchronizing pulses for making the polarity thereof commencing with each horizontal synchronizing pulse conform to current flow through said light cells connected to said last row conductor connected to said terminal maintained at said reference potential level thereby to provide a bipolar electrical signal;

means for taking periodic successive samples of said bipolar electrical signal; and

means for generating direct currents in proportion to the amplitude of said successive samples and for directing said currents from the time of said respective samples to corresponding light cell units connected to said last row conductor connected to said terminal maintained at said reference potential level.