System and method for achieving optimal display contrast in a mobile communication device

• US 7,843,413 B2
• Filed: 03/08/2007
• Issued: 11/30/2010
• Est. Priority Date: 11/06/2000
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Tran, Phat H., Lowles, Robert J., Reksnis, Marek
• Primary Examiner(s): Mengistu; Amare
• Assistant Examiner(s): PATEL, PREMAL R
• Application Number:
  US11/683,762
• Publication Number:
  US 20070146304A1
• Time in Patent Office: 1,363 Days
• Field of Search: 345/87, 345/204, 345/205, 345/250
• US Class Current: 345/87
• CPC Class Codes: G06F 3/04897 Special input arrangements or commands for improving display capability
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/36 using liquid crystals
• CPC Class Codes: H04M 1/22 Illumination; Arrangements for improving the visibility of characters on dials
• CPC Class Codes: H04M 1/72448 with means for adapting the functionality of the device according to specific conditions

Abstract

A method is for calibrating a contrast offset value for an LCD contrast control system in a mobile device. The method includes the steps of adjusting a user contrast setting on the mobile device to a desired optimal value, initializing the contrast offset value, determining a contrast ratio of the LCD, and incrementing the contrast offset value until the contrast ratio reaches a peak value.

Claims

1. A method for calibrating a contrast offset value for an LCD contrast control system in a mobile device, comprising:

adjusting a user contrast setting on the mobile device to a desired optimal value;

initializing the contrast offset value;

determining a contrast ratio of the LCD;

incrementing the contrast offset value until the determined contrast ratio reaches a peak value, while the user contrast setting remains at the optimal value;

storing the contrast offset value, at which the contrast ratio is a peak value, in a memory of the mobile device; and

using, by the mobile device, the stored contrast offset value to convert the user contrast setting into a hardware contrast setting.

2. The method of claim 1 wherein the contrast offset value is initialized to zero.

3. The method of claim 1 wherein the contrast offset value is initialized to a predetermined value.

4. The method of claim 1 further comprising:

taking an image of the LCD; and

determining the contrast ratio of the LCD from the image.

5. A method for calibrating a contrast offset value for an LCD contrast control system in a mobile device, comprising:

adjusting a user contrast setting on the mobile device to a desired optimal value;

initializing the contrast offset value;

determining a contrast ratio of the LCD; and

incrementing the contrast offset value until the contrast ratio reaches a peak value;

wherein the incrementing step includes;

determining whether the contrast ratio is higher than any previously measured values;

if the contrast ratio is higher than any previously measured values, then saving the contrast offset value and contrast ratio to a memory location, incrementing the contrast offset value, and determining an updated contrast ratio;

if the contrast ratio is not higher than any previously measured values, then determining whether the contrast ratio is a first measured value;

if the contrast ratio is the first measured value, then incrementing the contrast offset value and determining an updated contrast ratio; and

if the contrast ratio is not the first measured value, then setting the contrast offset on the mobile device to the saved contrast offset value.

6. The method of claim 5 wherein the contrast offset value is initialized to zero.

7. The method of claim 5 wherein the contrast offset value is initialized to a predetermined value.

8. The method of claim 5 further comprising:

taking an image of the LCD; and

determining the contrast ratio of the LCD from the image.

9. A method for calibrating a contrast offset value for an LCD contrast control system in a mobile device, comprising:

adjusting a user contrast setting on the mobile device to a desired optimal value;

initializing the contrast offset value;

determining a contrast ratio of the LCD; and

incrementing the contrast offset value until the contrast ratio reaches a peak value;

wherein the incrementing step includes;

determining whether the contrast ratio is higher than any previously measured values;

if the contrast ratio is higher than any previously measured values, then saving the contrast offset value and contrast ratio to a memory location, incrementing the contrast offset value, and determining an updated contrast ratio;

if the contrast ratio is not higher than any previously measured values, then determining whether the contrast ratio is a first measured value;

if the contrast ratio is the first measured value, then incrementing the contrast offset value and determining an updated contrast ratio;

if the contrast ratio is not the first measured value, then determining whether the contrast ratio is substantially less than the saved contrast ratio;

if the contrast ratio is not substantially less than the saved contrast ratio, then incrementing the contrast offset value and determining an updated contrast ratio; and

if the contrast ratio is substantially less than the save contrast ratio, then setting the contrast offset value on the mobile device to the saved contrast offset value.

10. The method of claim 9 wherein the contrast offset value is initialized to zero.

11. The method of claim 9 wherein the contrast offset value is initialized to a predetermined value.

12. The method of claim 9 further comprising:

taking an image of the LCD; and

determining the contrast ratio of the LCD from the image.