公开(公告)号：GB2482055B

公开(公告)日：2013-01-30

申请号：GB201111904

申请日：2011-07-12

Applicant: APPLE INC

Inventor： YOU CHENHUA ,  DROLET JEAN-JACQUES PHILLIPPE ,  CHEN WEI

IPC: G09G3/34 ,  H05B44/00

Abstract: Systems, methods, and devices are provided for maintaining a target white point on a light emitting diode (LED) based backlight. In one embodiment, the backlight may include two or more groups of LEDs, each driven at a respective driving strength. Each group may include LEDs of a different chromaticity, and the respective driving strengths may be adjusted, for example, by varying the duty cycles, to maintain the target white point. To ensure that the white point may be maintained over an operational temperature range of the backlight, the LEDs may be selected so that the chromaticities of each group of LEDs are separated by at least a minimum chromaticity difference. Further, the LEDs may be selected so that at the equilibrium temperature of the backlight, the LEDs may produce the target white point when driven at substantially equal driving strengths.

公开(公告)号：HK1166173A1

公开(公告)日：2012-10-19

申请号：HK12106750

申请日：2012-07-10

Applicant: APPLE INC

Inventor： YOU CHENHUA ,  DROLET JEAN-JACQUES PHILLIPPE ,  CHEN WEI

IPC: H05B44/00

Abstract: Systems, methods, and devices are provided for maintaining a target white point on a light emitting diode (LED) based backlight. In one embodiment, the backlight may include two or more groups of LEDs, each driven at a respective driving strength. Each group may include LEDs of a different chromaticity, and the respective driving strengths may be adjusted, for example, by varying the duty cycles, to maintain the target white point. To ensure that the white point may be maintained over an operational temperature range of the backlight, the LEDs may be selected so that the chromaticities of each group of LEDs are separated by at least a minimum chromaticity difference. Further, the LEDs may be selected so that at the equilibrium temperature of the backlight, the LEDs may produce the target white point when driven at substantially equal driving strengths.

公开(公告)号：GB2482055A

公开(公告)日：2012-01-18

申请号：GB201111904

申请日：2011-07-12

Applicant: APPLE INC

Inventor： YOU CHENHUA ,  DROLET JEAN-JACQUES PHILLIPPE ,  CHEN WEI

IPC: G09G3/34 ,  H05B44/00

Abstract: Systems, methods, and devices are provided for maintaining a target white point on a light emitting diode (LED) based backlight 32. In one embodiment, the backlight 32 may include two or more groups of LEDs N3, N8, each driven independently at a respective driving strength. Each group may include LEDs N3, N8 of a different chromaticity, and the respective driving strengths 88, 90 may be adjusted, for example, by varying the duty cycles, to compensate for age effects or temperature changes to maintain the target white point. To ensure that the white point may be maintained over an operational temperature range of the backlight 32, the LEDs N3, N8 may be selected so that the chromaticities of each group of LEDs N3, N8 are separated by at least a minimum chromaticity difference. Further, the LEDs N3, N8 may be selected so that at the equilibrium temperature of the backlight 32, the LEDs N3, N8 may produce the target white point when driven at substantially equal driving strengths.