Automatic brightness control for displays

• US 9,129,549 B2
• Filed: 05/22/2013
• Issued: 09/08/2015
• Est. Priority Date: 03/13/2000
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Bell, Cynthia S.
• Primary Examiner(s): Lao, Lun-Yi
• Assistant Examiner(s): Siddiqui, Md Saiful A
• Application Number:
  US13/900,090
• Publication Number:
  US 20130257835A1
• Time in Patent Office: 839 Days
• Field of Search: 345/102, 345107-108, 345/207, 345/211, 345/690, 348/51, 348/362, 348602-603, 348657-658, 349 61- 64
• US Class Current: 1/1
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 5/10 Intensity circuits

Abstract

An automatic brightness adjustment for devices with displays includes the capability to assess ambient light. The assessment may be made using circuitry, such as a light meter circuit, by exploiting exposure control circuitry, or using other approaches. The ambient light value is sent to a brightness adjustment driver, which may employ a look-up table to keep track of brightness adjustments for particular ambient conditions. The look-up table may include distinct adjustment values.

Claims

1. A mobile apparatus comprising:

a display;

an imager to capture an image, provide an exposure for the image and adjust a brightness of the display, wherein said imager comprises a light sensor to detect an amount of light in a surrounding area, wherein the light sensor accumulates light energy over an integration interval to provide an indication of the amount of light; and

a processor to determine a perceived brightness value based on an equation whose value varies with the detected amount of light, wherein the equation comprises a factor that is a direct adaptation effect and a factor that is a lateral adaptation effect, and wherein conflicts between direct and lateral adaptations of a user'"'"'s eye are to be avoided based on the perceived brightness value, wherein the lateral adaptation effect comprises a sum of weighted adaptations to spot luminances in proportion to their angular displacements from an axis of vision.

2. The apparatus of claim 1, further comprising:

a look up table to translate the perceived brightness value to a display brightness setting.

3. The apparatus of claim 2, wherein the look-up table is adaptable to a type of display being used.

4. The apparatus of claim 1, wherein the display comprises a microdisplay.

5. The apparatus of claim 4, wherein the microdisplay comprises one of a frontlit liquid crystal display (LCD), a backlit transmissive LCD or an organic light emitting diode (LED).

6. The apparatus of claim 1, wherein the display comprises a direct view LCD.

7. The apparatus of claim 1, wherein the imager comprises a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) device.

8. A mobile apparatus comprising:

a display;

an imager to capture an image, provide an exposure for the image and adjust a brightness of the display;

a light sensor to detect an amount of light in a surrounding area; and

a processor to determine a perceived brightness value based on an equation that provides a value that varies with the detected amount of light;

wherein the equation comprises;

B=AL^1/3−

S

where

A=100/(L_AVG^1/3+K),

S=100(Σ

S_iA_iL_i^1/3),

B is a perceived brightness in LUX,

A is a direct adaptation effect,

L, L_i and L_AVG are environmental luminances in cd/m²,

K=3.6, and

S is a lateral adaptation effect comprising a sum of weighted adaptations to spot luminances in proportion to their angular displacement from an axis of vision.