Digital display system for variable color decimal point indication

• US 6,281,864 B1
• Filed: 03/15/1999
• Issued: 08/28/2001
• Est. Priority Date: 01/15/1986
• Status: Expired due to Fees

• Current Assignee: Texas Digital Systems, Inc. (NCR Voyix Corporation)
• Original Assignee: Texas Digital Systems, Inc. (NCR Voyix Corporation)
• Inventors: Havel, Karel
• Primary Examiner(s): Chow, Dennis-Doon
• Assistant Examiner(s): Awad, Amr
• Application Number:
  US09/268,769
• Time in Patent Office: 897 Days
• Field of Search: 345/81, 345/82, 345/83, 345/151, 345/150, 324/96, 324/99.D, 257/89, 257/90
• US Class Current: 345/83
• CPC Class Codes: G01R 13/02 for displaying measured electric variables in digital form
• CPC Class Codes: G01R 13/26 Circuits for controlling the intensity of the electron beam or the colour of the display
• CPC Class Codes: G01R 13/405 using a plurality of active, i.e. light emitting, e.g. electro-luminescent elements, i.e. bar graphs
• CPC Class Codes: G01R 15/125 for digital multimeters
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• 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 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 3/14 Semiconductor devices, e.g. diodes

Abstract

A variable color light emitting diode digital display system automatically exhibits integers and decimal numbers in different colors. A logic circuit is provided for detecting the presence or absence of a decimal point in a string of digits. The color of the exhibited digits is controlled in accordance with the detection.

Claims

1. A display system comprising:

a plurality of adjacent variable color digital display elements, each said display element including a plurality of display segments and a decimal point segment for selectively exhibiting a plurality of strings of digits with a decimal point, each said display element including a color control input for illuminating it in a color in accordance with a color control signal, the color control inputs of all said display elements being interconnected;

decoder means having a plurality of inputs for receiving input codes defining a string of digits with or without a decimal point, a plurality of decoder outputs for developing drive signals for selectively energizing said display segments, and a plurality of decimal point outputs for developing drive signals for energizing a certain of said decimal point segments, if the decimal point is present in said string of digits;

means responsive to said decoder outputs and to said decimal point outputs for exhibiting on said display means the string of digits which may include a decimal point;

means for interrogating said decimal point outputs to determine whether there is a decimal point in the string of digits and for developing an output signal accordingly; and

color control means for coupling said output signal to the interconnected color control inputs for illuminating all digits in the string in a first color when said decimal point was detected, and in a second color when said decimal point was not detected.

2. A display system comprising:

a plurality of adjacent variable color digital display elements, each said display element including a plurality of display segments and a decimal point segment for selectively exhibiting a plurality of strings of digits with a decimal point, each said display element including a color control input for illuminating it in a color in accordance with a color control signal, the color control inputs of all said display elements being interconnected;

decoder means having a plurality of inputs for receiving input codes defining a string of digits with or without a decimal point, a plurality of decoder outputs for developing drive signals for selectively energizing said display segments, and a plurality of decimal point outputs for developing drive signals for energizing a certain of said decimal point segments, if the decimal point is present in said string of digits;

means responsive to said decoder outputs and to said decimal point outputs for exhibiting on said display means the string of digits which may include a decimal point;

a logic device including a plurality of logic inputs equal in number to the plurality of said decoders, said inputs being respectively connected to said decimal point outputs of said decoders, and a logic output, for developing an output logic signal in accordance with the conditions of said decimal point decoder outputs; and

color control means for coupling said logic output to the interconnected color control inputs, for illuminating all digits in the string in a first color when said decimal point was detected, and in a second color when said decimal point was not detected.

3. A display system comprising:

a plurality of side by side positioned variable color light emitting diode digital display elements, each said display element including a plurality of display segments and a decimal point segment, each said display element including a first color control input for illuminating upon activation said display element in a first color, and a second color control input for illuminating upon activation said display element in a second color, said first color control inputs and said second color control inputs of all said display elements being respectively interconnected;

a plurality of decoders equal in number to the plurality of said display elements and respectively associated with said display elements, each said decoder having a plurality of inputs for receiving an input code defining a digit, a plurality of decoder outputs for developing drive signals for energizing selective groups of display segments in the associated display element, and a decimal point output for developing an active decimal point drive signal for energizing the decimal point segment in the associated display element, when there is a decimal point in said string of digits;

means responsive to the decoder outputs and to the decimal point outputs for exhibiting on said display elements a string of digits which may include a decimal point;

a logic device including a plurality of logic inputs equal in number to the plurality of said decoders, said inputs being respectively connected to said decimal point outputs of said decoders, a first logic output for developing an active logic signal when said active decimal point drive signal is detected, and a second logic output for developing an active logic signal when said active decimal point drive signal is not detected; and

color control means for coupling said first logic output to the interconnected first color control inputs, and for coupling said second logic output to the interconnected second color control inputs.