Homochromatic and Color Display Assembly on an Electronic Device and Method for Operation Thereof

• US 20080284718A1
• Filed: 05/07/2008
• Published: 11/20/2008
• Est. Priority Date: 05/18/2007
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Huang, Jie, Khor, Weng Woh
• Granted Patent: US 9,064,465 B2
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

The present invention provides an electronic device (100) comprising a homochromatic liquid crystal display (155), a color liquid crystal display (165), and a backlight (175) having a light-pipe (220), the homochromatic liquid crystal display, the color liquid crystal display and the light-pipe being positioned in overlapping relation to each other, the light-pipe arranged to direct light (230d) through both the homochromatic liquid crystal display and the color liquid crystal display, a homochromatic liquid crystal display driver (150) arranged to generate an image on the homochromatic liquid crystal display in response to an image signal, a color liquid crystal display driver (160) arranged to generate an image on the color liquid crystal display in response to an image signal, a processor (103) arranged to receive a light control signal (LS1), and to forward an image signal to one of the homochromatic liquid crystal display driver or the color liquid crystal display driver dependent on the light control signal.

Claims

1. An electronic device comprising:

a homochromatic liquid crystal display, a color liquid crystal display, and a backlight having a light-pipe;

the homochromatic liquid crystal display, the color liquid crystal display and the light-pipe being positioned in overlapping relation to each other, the light-pipe arranged to direct light through both the homochromatic liquid crystal display and the color liquid crystal display;

a homochromatic liquid crystal display driver arranged to generate an image on the homochromatic liquid crystal display in response to an image signal;

a color liquid crystal display driver arranged to generate an image on the color liquid crystal display in response to an image signal; and

a processor arranged to receive a light control signal, and to forward an image signal to one of the homochromatic liquid crystal display driver or the color liquid crystal display driver dependent on the light control signal.

2. An electronic device as claimed in claim 1, wherein the color liquid crystal display is positioned between the homochromatic liquid crystal display and the light-pipe.

3. An electronic device as claimed in claim 1, further comprising a light sensor arranged to generate the light control signal in response to ambient light incident on the light sensor.

4. An electronic device as claimed in claim 3, wherein the processor is arranged to forward the image signal to the homochromatic liquid crystal display driver in response to a level of ambient light incident on the light sensor being below a predetermined level.

5. An electronic device as claimed in claim 1, further comprising a user actuable control input arranged to generate the light control signal in response to user actuation, the processor arranged to forward the image signal to the other of said homochromatic liquid crystal display driver or said color liquid crystal display driver in response to light control signal.

6. An electronic device as claimed in claim 1, wherein the homochromatic liquid crystal display and the color liquid crystal display each comprise twisted-nematic liquid crystal sandwiched between two polarizing filters having perpendicular polarizing directions, the polarizing filters adjacent each other from the color liquid crystal display and the homochromatic liquid crystal display having the same polarizing direction.

7. An electronic device as claimed in claim 1, wherein the processor is further arranged to control the backlight dependent on whether the homochromatic liquid crystal display or the color liquid crystal display is being driven.

8. An electronic device as claimed in claim 1, wherein the homochromatic liquid crystal display driver and the color liquid crystal display driver are implemented by the processor.

9. A method of operating a display assembly of an electronic device, the method comprising:

measuring a level of ambient light at the device; and

generating an image on the display assembly, the image being homochromatic or color dependent on the level of ambient light.

10. A method as claimed in claim 9, wherein the image is homochromatic when the level of ambient light is below a predetermined level of ambient light.

11. A method as claimed in claim 9, wherein the display assembly comprises a homochromatic liquid crystal display for displaying a homochromatic image and a color liquid crystal display for displaying a color image, the homochromatic liquid crystal display and the color liquid crystal display being positioned in overlapping relation to each other.