Protected LCD particularly for the instrument panel of a motor vehicle installation having a branch line between the power supply and LCD output

• US 6,317,172 B1
• Filed: 01/27/1999
• Issued: 11/13/2001
• Est. Priority Date: 01/29/1998
• Status: Expired due to Term

• Current Assignee: Valeo Electronique
• Original Assignee: Valeo Electronique
• Inventors: Huynh, Tan Duc
• Primary Examiner(s): Malinowski, Walter J.
• Application Number:
  US09/238,121
• Time in Patent Office: 1,021 Days
• Field of Search: 349/149, 349/40, 345/58, 345/117, 340/461, 340/525
• US Class Current: 349/40
• CPC Class Codes: G09G 2330/02 Details of power systems and of start or stop of display operation
• CPC Class Codes: G09G 3/36 using liquid crystals

Abstract

A device, particularly for the instrument panel of a motor vehicle, comprises a liquid crystal display module comprising a multiplicity of parallel inputs connected via a multiplicity of control lines to a multiplicity of outputs of a control module supplied by an electrical power supply. The output of the display module and the electrical power supply are connected to an electrical ground. A branch line has, on the one hand, an input connected to the electrical power supply and an output connected directly to the output of the display module, and has, on the other hand, an impedance considerably lower than the corresponding impedance of each pair formed by a control line and the output of the associated control module. The device is thus protected against electrostatic discharges.

Claims

1. A liquid crystal display module device, comprising:

a display module for controlling a display, the display module having at least one display module input for receiving an electrical command signal which alters the display, the display module further having a display module output connected to an electrical ground;

a control module supplied by an electrical power supply and having at least one control module output for transmitting the electrical command signal to the display module;

at least one control line, each control line connecting one control module output to one display module input for transmitting the electrical command signal therebetween, wherein each control line, display module input and control module output form a pair; and

at least one branch line operatively connected between said electrical power supply and the display module output, said at least one branch line for preventing an excessive electrostatic discharge on the at least one control line and having a first impedance value substantially lower than a second impedance value including each pair.

2. The device of claim 1, wherein a ratio of the second impedance value to the first impedance value is at least 10.

3. The device of claim 2, wherein said ratio is at least 100.

4. The device of claim 2, wherein said ratio is greater than 1000.

5. The device of claim 1, wherein the at least one control line is an electrically conductive connecting element.

6. The device of claim 1, wherein the at least one branch line is an electrically conductive connecting element.

7. The device of claim 1, wherein the display module includes a grounding area, wherein the display module output and the at least one branch lines are in electrical communication with the grounding area.

8. The device of claim 1, wherein the control module includes at least one branch output in electrical communication with the electrical power supply and the at least one branch lines.

9. The device of claim 1, wherein the display module output is connected to the electrical ground via a coupling resistor.

10. A motor vehicle comprising an instrument panel of at least one of a heating and an air conditioning installation, the instrument panel including the liquid crystal display device of claim 1.