Display drive matrix

• US 3,877,008 A
• Filed: 08/03/1973
• Issued: 04/08/1975
• Est. Priority Date: 06/25/1971
• Status: Expired due to Term

• Current Assignee: Thomas R. Payne
• Original Assignee: Thomas R. Payne
• Inventors: Payne, Thomas R.
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Curtis, Marshall M.
• Application Number:
  US05/385,499
• Time in Patent Office: 613 Days
• Field of Search: 340/324R,324M,336,166R,166EL,174TB,174LC,176 178/30 219/201,216
• US Class Current: 345/106
• CPC Class Codes: G06K 15/028 by thermal printers

Abstract

A thermal display having a plurality of heat dissipative elements arrayed in a matrix comprising a plurality of rows and columns is disclosed. Current through each heat dissipative element is controlled by a separate heater transistor. The bases of all heater transistors in a row are connected together and the emitters of all the heater transistors in a column are connected together. A driver circuit for each row in the matrix applies a voltage to the common connected bases of the heater transistors and a column driver circuit for each column in the matrix produces a driving potential on the common connected emitters of the heater transistors. A MOS character generator produces a scanned output signal which sequentially selects the rows by turning the row driver circuits on, and simultaneously selectively turns the column driver circuits on in accordance with the image to be produced. The heater transistors for the elements which have both row and column select signals applied simultaneously are turned on to form a character within the matrix. The heater transistors in each row are positively driven off by shunting the entire row line to ground using the logic signal from the succeeding row.

Claims

1. In a display system, the combination of:

a. a plurality of switching transistors arranged in columns and rows with each column comprising one transistor from each row and each row comprising one transistor from each column;

b. row lines or column lines commonly connecting the bases of all transistors in a row or column;

c. the other of said row lines or column lines electrically connecting the emitters of all transistors in a row or column;

d. row select means coupled to the row lines for selecting a specific row for actuation;

e. column select means coupled to the column lines for selecting specific columns for actuation;

f. means for sequentially actuating one of said row select means and said column select means to obtain sequential actuation of the corresponding row lines or column lines; and

g. means for selectively actuating the other of said row select means and said column select means, in accordance with the image to be displayed, in synchronization with said sequential actuation of said one thereof, such that each coincidental actuation of a row line and a column line turns on a corresponding transistor.

2. The display system according to claim 1 and further including a matrix of load elements for generating visible character images when energized in predetermined combinations, said load elements respectively connected to a collector of a switching transistor.

3. The display system according to claim 1 wherein the row select means includes means for discharging the previous row line in response to actuation of the row line next in sequence.

4. The display system according to claim 1 further including means for deactuating all the column lines after all row lines have been sequentially actuated.

5. The display system according to claim 1 wherein said load elements comprise heat dissipating devices, and said display system constitutes a thermal printing system.

6. The display system of claim 1 wherein said means for selectively actuating the other of said row select means and said column select means includes a driver circuit for selectively connecting each corresponding row line or column line to a supply voltage in response to logic control signals;

and logic means coupled to said driver circuit for selectively operating said driver circuit to connect the corresponding row lines or column lines to the voltage supply in accordance with the image to be displayed.