System and method for generating high-luminance windows on a computer display device

• US 6,686,925 B1
• Filed: 11/01/2000
• Issued: 02/03/2004
• Est. Priority Date: 07/25/1997
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Apple Computer Incorporated (Apple Inc.)
• Inventors: Cappels, Richard D.
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): Nguyen, Jimmy H
• Application Number:
  US09/705,140
• Time in Patent Office: 1,189 Days
• Field of Search: 345/620, 345/204, 345/211, 345/212, 345/690, 348/596, 348/380, 348/511, 348/528, 348/564, 348/565
• US Class Current: 345/620
• CPC Class Codes: G09G 1/002 Intensity circuits G09G1/06 - G09G1/28 take precedence
• CPC Class Codes: G09G 2320/0686 with two or more screen areas displaying information with different brightness or colours
• CPC Class Codes: G09G 5/14 Display of multiple viewports

Abstract

A system and method for generating high-luminance windows on a computer display device includes a video amplifier which provides video signals to a cathode ray tube, a window generator which provides a window signal to the video amplifier to generate the high-luminance window, and an automatic beam limiter which controls the beam current provided to the cathode ray tube during period of the high-luminance window.

Claims

1. A system for generating a high-luminance viewing window on a display screen, the system comprising:

a video application for displaying a moving video image within said high-luminance viewing window, wherein said video application generates a window request when a moving video image is to be displayed in said high-luminance viewing window;

a means for processing said window request and responsively providing a plurality of window control signals;

a window generator connected to said processing means for receiving said plurality of window control signals, wherein said window control signals include a window enable signal, a vertical start signal and a vertical end signal to provide the vertical position and vertical size of said high-luminance viewing window, and a horizontal start signal and a horizontal end signal to provide the horizontal position and size of said high-luminance viewing window, and wherein said window generator includes

an AND gate, wherein said window enable signal is a first input of the AND gate;

a vertical delay for receiving said vertical start signal and a vertical window pulse generator for receiving said vertical end signal, wherein said vertical delay and said vertical window pulse generator provide a vertical component signal to a second input of the AND gate; and

a horizontal delay for receiving said horizontal start and a horizontal window pulse generator for receiving said horizontal end signal, wherein said horizontal delay and said horizontal window pulse generator provide a horizontal component signal to a third input of the AND gate, and wherein said AND gate generates a window pulse signal only during the time period said window enable signal, said vertical component signal, and said horizontal component signal indicate said high-luminance viewing window is to be displayed on said display screen;

an automatic beam limiter connected to said window generator for receiving said window pulse signal and responsively generating an analog window signal;

a video amplifier connected to said display screen and to said automatic beam limiter for receiving said analog window signal and a video signal comprised of information to be displayed on said display screen including information to be displayed in said high-luminance viewing window, wherein said video amplifier operates in a normal gain mode when said analog window signal is in a first state and said video amplifier operates in a high gain mode when said analog window signal is in a second state, and wherein said analog window signal is in said second state when said high-luminance viewing window is displayed on said display screen so that said moving video image has a higher luminance level than the remainder of the information displayed on said display screen; and

a power supply connected to said automatic beam limiter and to said display screen for providing a beam current to said display screen, wherein said automatic beam limiter limits the luminance level within said high-luminance viewing window by limiting an average beam current provided to said display screen during the time period the high-luminance viewing window is displayed on said display screen.