Large scale display panel apparatus

• US 4,367,464 A
• Filed: 05/29/1980
• Issued: 01/04/1983
• Est. Priority Date: 05/29/1979
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Tomimatsu, Noriyuki, Kurahashi, Koichiro
• Primary Examiner(s): Curtis, Marshall M.
• Application Number:
  US06/154,262
• Time in Patent Office: 950 Days
• Field of Search: 340/701, 340/703, 340/704, 340/789, 340/791, 340/792, 340/772, 340/752, 340/793
• US Class Current: 345/22
• CPC Class Codes: G09G 3/22 using controlled light sources

Abstract

A large scale display device such as a stadium or advertising display in which a plurality of light emitting elements constituted by cathode-ray tubes are arranged in a plane to display color images and characters. Specifically, light emitting elements are constituted by cathode-ray tubes having three primary color light emitting elements. A drive circuit is provided for each color of each of the light emitting element to selectively turn on and off the light emitting element. The drive circuit has brightness adjusting means for adjusting the intensity of light emitted by each light emitting element. A memory circuit is connected to each drive circuit for supplying a binary control signal to the drive circuit to selectively turn on and off the corresponding light emitting element.

Claims

1. A large scale color display panel capable of displaying an image containing half tones and of varying intensity, comprising:

a plurality of light emitting elements, each of said light emitting elements being capable of emitting light in a selected combination of three primary colors, each of said light emitting elements comprising three cathode-ray tubes, each cathode-ray tube comprising at least one fluorescent screen for emitting light of one of said primary colors from substantially an entire front surface thereof and an electron gun for producing an unfocused flood of electrons directed toward said fluorescent screen;

a plurality of drive circuits, one of said drive circuits being provided for each said electron gun for turning on and off said electron gun with an on-to-off time ratio determined in accordance with an intensity of light to be emitted by the cathode-ray tube of which said electron gun forms a part, and hence a hue of light to be emitted from the light emitting element of which said cathode-ray tube forms a part;

a plurality of memory means, one of said memory means being provided for each said drive circuit for storing a binary control signal representing and on/off state of a corresponding one of said electron guns; and

brightness adjusting means coupled to each of said drive circuits for setting a brightness level of light to be emitted by controlling a magnitude of drive of said electron guns.

2. The display device as claimed in claim 1 in which said memory circuit means comprises a flip-flop circuit.

3. The display device as claimed in claim 1 wherein each of said drive circuits comprises a transistor which is selectively rendered conductive and non-conductive in response to said control signal of said memory circuit to control a cathode voltage of said cathode-ray tube.

4. The display device as claimed in claim 1 wherein each of said drive circuits comprises a transistor which is selectively rendered conductive and non-conductive in response to said control signal of said memory circuit to control a cathode voltage of said cathode-ray tube.

5. The display device as claimed in claims 3 or 4 wherein said brightness adjusting means comprises a variable resistor for controlling a cathode current of said cathode-ray tube, said brightness adjusting means being connected in series with a power source and said transistor.