Systems and methods for compensating brightness uniformity of backlit image displays

• US 20090086473A1
• Filed: 09/28/2007
• Published: 04/02/2009
• Est. Priority Date: 09/28/2007
• Status: Active Grant

• Current Assignee: Dell Products LP (Dell Technologies Inc.)
• Original Assignee: Dell Products LP (Dell Technologies Inc.)
• Inventors: Tan, Ben Jin, Chung, Thomas Tze Fung
• Granted Patent: US 7,717,601 B2
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G02F 1/13318 Circuits comprising a photodetector
• CPC Class Codes: G02F 1/133604 with lamps
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 3/006 Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: Y10S 362/802 Position or condition responsive switch

Abstract

Systems and methods for compensating brightness uniformity of transmissive backlit display devices using auxiliary lights to provide additional light to compensate light provided by the main backlights of a backlit image display device. Auxiliary lights may be, for example, embedded into the light pipe area of an image display and/or placed in any other suitable position relative to the main backlights that is suitable for compensating the main backlights. In one example implementation, brightness uniformity of a transmissive image display may be at least partially compensated based at least in part on measured luminance of one or more areas of the display.

Claims

1. A method of compensating brightness uniformity of display for an information handling system, comprising:

providing a transmissive display panel and one or more main backlight lamps configured to provide light to said transmissive display panel;

providing one or more auxiliary backlight lamps configured to supplement light provided by said main backlight lamps to light said transmissive display panel;

lighting an area of said transmissive display panel with said main backlight lamps; and

providing light from said auxiliary backlight lamps to supplement light provided by said main backlight lamps to light said area of said transmissive display panel;

wherein said area of said transmissive display panel is lit with a first brightness uniformity by said main backlight lamps alone; and

wherein said area of said transmissive display panel is lit with a second brightness uniformity by said main backlight lamps and said auxiliary backlight lamps together, said second brightness uniformity being greater than said first brightness uniformity.

2. The method of claim 1, wherein said transmissive display panel comprises a liquid crystal display (LCD) panel;

wherein said main backlight lamps comprise cold cathode fluorescent lamps (CCFLs); and

wherein said auxiliary backlight lamps comprises light emitting diodes (LEDs).

3. The method of claim 1, wherein said auxiliary backlight lamps comprise at least one auxiliary backlight positioned to emit light at one or more edge area locations of said transmissive display panel;

or wherein said auxiliary backlight lamps comprise at least one auxiliary backlight positioned to emit light at one or more interior area locations of said transmissive display panel;

or a combination thereof.

4. The method of claim 1, further comprising providing a light pipe area configured to provide light to said transmissive display panel;

wherein said main backlight lamps extend from at least one external edge of said light pipe area; and

wherein said auxiliary backlight lamps also extend from said same at least one external edge of said light pipe area in a position adjacent said main backlight lamps.

5. The method of claim 4, wherein said main backlight lamps comprise at least two main backlight lamps extending from said at least one external edges of said light pipe area;

and wherein said auxiliary backlight lamps comprise at least one auxiliary backlight also extending from said same at least one external edge of said light pipe area adjacent and in-between said at least two main backlight lamps.

6. The method of claim 4, wherein said main backlight lamps comprise at least two main backlight lamps extending from said at least one external edges of said light pipe area toward an interior area of said light pipe area;

and wherein said auxiliary backlight lamps comprise at least one auxiliary backlight disposed at a location adjacent an interior area of said transmissive display panel and in-between said at least two main backlight lamps.

7. The method of claim 1, further comprising providing one or more light metering sensors configured to monitor brightness at one or more points of said transmissive display panel;

measuring brightness data corresponding to said first brightness uniformity at said one or more points of said transmissive display panel; and

adjusting brightness of said one or more auxiliary backlight lamps based at least in part on said measured brightness data and one or more auxiliary backlight control components to light said transmissive display panel with said second brightness uniformity.

8. A display for an information handling system, comprising:

a transmissive display panel and one or more main backlight lamps configured to provide light to an area of said transmissive display panel; and

one or more auxiliary backlight lamps configured to supplement light provided by said main backlight lamps to light said transmissive display panel;

wherein said area of said transmissive display panel is lit with a first brightness uniformity by said main backlight lamps alone; and

wherein said area of said transmissive display panel is lit with a second brightness uniformity by said main backlight lamps and said auxiliary backlight lamps together, said second brightness uniformity being greater than said first brightness uniformity.

9. The information handling system of claim 8, wherein said transmissive display panel comprises a liquid crystal display (LCD) panel;

wherein said main backlight lamps comprise cold cathode fluorescent lamps (CCFLs); and

wherein said auxiliary backlight lamps comprises light emitting diodes (LEDs).

10. The information handling system of claim 8, wherein said auxiliary backlight lamps comprise at least one auxiliary backlight positioned to emit light at one or more edge area locations of said transmissive display panel;

wherein said auxiliary backlight lamps comprise at least one auxiliary backlight positioned to emit light at one or more interior area locations of said transmissive display panel;

or a combination thereof.

11. The information handling system of claim 8, further comprising a light pipe area configured to provide light to said transmissive display panel;

wherein said main backlight lamps extend from at least one external edge of said light pipe area; and

wherein said auxiliary backlight lights also extend from said same at least one external edge of said light pipe area in a position adjacent said main backlight lamps.

12. The information handling system of claim 11, wherein said main backlight lamps comprise at least two main backlight lamps extending from said at least one external edges of said light pipe area;

and wherein said auxiliary backlight lamps comprise at least one auxiliary backlight also extending from said same at least one external edge of said light pipe area adjacent and in-between said at least two main backlight lamps.

13. The information handling system of claim 11, wherein said main backlight lamps comprise at least two main backlight lamps extending from said at least one external edges of said light pipe area toward an interior area of said light pipe area;

and wherein said auxiliary backlight lamps comprise at least one auxiliary backlight disposed at a location adjacent an interior area of said transmissive display panel and in-between said at least two main backlight lamps.

14. The information handling system of claim 8, further comprising one or more light metering sensors configured to monitor brightness at one or more points of said transmissive display panel corresponding to said first brightness uniformity at said one or more points of said transmissive display panel;

and one or more auxiliary backlight control components configured to adjust brightness of said one or more auxiliary lights based at least in part on said measured brightness data from said one or more light metering sensors to light said transmissive display panel with said second brightness uniformity.

15. A method of compensating brightness uniformity of a display for an information handling system, comprising:

providing a transmissive display panel, one or more backlights configured for lighting said transmissive display panel, and one or more auxiliary backlight lamps configured for selectably lighting said transmissive display panel;

lighting said transmissive display panel with one or more main backlight lamps; and

increasing the brightness uniformity of said transmissive display panel by selectably adjusting the brightness of said one or more auxiliary backlight lamps.

16. The method of claim 15, said method comprising:

lighting said transmissive display panel with said one or more main backlight lamps;

then measuring a brightness of said lighted transmissive display panel at one or more points across the display area of said transmissive display panel;

then determining a first brightness uniformity value based on said measured brightness of said transmissive display panel; and

then increasing the brightness uniformity of said transmissive display panel by selectably adjusting the brightness of said one or more auxiliary backlight lamps based at least in part on said determined first brightness uniformity value.

17. The method of claim 16, wherein said method comprises measuring brightness of said transmissive display panel at multiple points across the display area of said transmissive display panel;

determining said first brightness uniformity value of said transmissive display panel by determining the minimum measured brightness value of all measured brightness points divided by the maximum measured brightness of all measured brightness points; and

adjusting the brightness of said one or more auxiliary backlight lamps to achieve a second brightness uniformity value for said transmissive display panel that is greater than said first brightness uniformity value.

18. The method of claim 16, further comprising providing one or more light metering sensors as integral components of a display device that comprises said transmissive display panel;

and iteratively performing in real time said steps of measuring brightness of said transmissive display panel at said one or more points using said integral light metering sensors, determining a first brightness uniformity value, and increasing the brightness uniformity of said transmissive display panel.

19. The method of claim 16, further comprising providing one or more external light metering sensors as external components of a display device that comprises said transmissive display panel;

and measuring brightness of said transmissive display panel at said one or more points using said external light metering sensors.

20. The method of claim 16, further comprising outputting said determined first brightness uniformity value to a user;

and increasing the brightness uniformity of said transmissive display panel by adjusting the brightness of said one or more auxiliary backlight lamps based on input received from said user.

21. An information handling system and display, comprising:

a transmissive display panel;

one or more backlights configured for lighting said transmissive display panel;

one or more auxiliary backlight lamps configured for selectably lighting said transmissive display panel; and

one or more auxiliary backlight control components configured to increase a brightness uniformity of said transmissive display panel by selectably adjusting the brightness of said one or more auxiliary backlight lamps.

22. The system of claim 21, further comprising:

one or more light metering sensors coupled to said one or more auxiliary backlight control components, said one or more light metering sensors being integral components of a display device that comprises said transmissive display panel, and being configured to measure a brightness of said transmissive display panel at one or more points;

wherein said one or more auxiliary backlight control components are configured to increase a brightness uniformity of said transmissive display panel by selectably adjusting the brightness of said one or more auxiliary backlight lamps based on brightness of said transmissive display panel measured at said one or more points by said one or more light metering sensors.

23. The method of claim 22, wherein said one or more auxiliary backlight control components are configured to iteratively and in real time increase a brightness uniformity of said transmissive display panel by selectably adjusting the brightness of said one or more auxiliary backlight lamps based on brightness of said transmissive display panel measured at said one or more points by said one or more light metering sensors.