DISPLAY STACK-UP FOR A MOBILE ELECTRONIC DEVICE HAVING INTERNAL AND EXTERNAL DISPLAYS

• US 20080002115A1
• Filed: 06/30/2006
• Published: 01/03/2008
• Est. Priority Date: 06/30/2006
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: POLAK, ROBERT D.
• Granted Patent: US 7,768,605 B2
• Time in Patent Office: Days
• US Class Current: 349/114
• CPC Class Codes: G02F 1/133342 for double-sided displays
• CPC Class Codes: G02F 1/133616 Front illuminating devices
• CPC Class Codes: G02F 1/1347 Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
• CPC Class Codes: G02F 1/13718 based on a change of the texture state of a cholesteric liquid crystal
• CPC Class Codes: G02F 1/1391 Bistable or multi-stable liquid crystal cells G02F1/141 takes precedence

Abstract

A display stack-up (300) is provided for a mobile electronic device (100) having an internal and external display, for example, a clamshell style mobile phone. The display stack-up comprises a backlight unit (114) and an external display device (110) having bi-stable optical states. The external display device (110) is placed in contact with, and is optically coupled to, the backlight unit (114). The display stack-up further comprises an internal display device (106) which is placed in contact with, and is optically coupled to, the external display device (110).

Claims

1. A display stack-up comprising:

a backlight unit;

an external display device having bi-stable optical states, said states including a transmissive optical state and a reflective optical state, wherein the external display device is placed in contact against the transmissive backlight layer; and

an internal display device, wherein the internal display device is placed in contact against the external display device.

2. The display stack-up of claim 1, wherein the external display device is a cholesteric display.

3. The display stack-up of claim 2, wherein said external display device in said transmissive optical state allows transmission of light from said backlight unit through said external display device to said internal display device, and wherein said external display device in said reflective optical state reflects light from said backlight back through said backlight and away from said internal display device.

4. The display stack-up of claim 3, wherein said external display device in said transmissive optical state has an optical diffusion property.

5. The display stack-up of claim 1, wherein the internal display device provides a contrast backplane for said external display device when said internal display device is powered off.

6. A mobile electronic device comprising:

an internal display device;

an external display device having a bi-stable optical property, said external display device being in contact with said internal display device;

a backlight in contact with said external display device; and

a control component coupled to said internal display device, said external display device, and said backlight.

7. The mobile electronic device of claim 6, further comprising:

a first housing member having a internal surface and an external surface, said first housing member containing said internal display device, said external display device and said backlight; and

a second housing member hingedly connected to said first housing member, said first and said second housing members configurable in opened and closed positions, wherein at least a portion of said internal surface is in contact with said second housing member when said first housing member and said second housing member are configured in said closed position.

8. The mobile electronic device of claim 7, wherein said internal display device is substantially in parallel with, and visible through, said internal surface and wherein said external display device is substantially in parallel with, and visible through, said external surface.

9. The mobile electronic device of claim 8, further comprising a light source coupled to said backlight.

10. The mobile electronic device of claim 8, wherein the external display device is a cholesteric display.

11. The mobile electronic device of claim 8, wherein the internal display device is a high resolution color active matrix display.

12. The mobile electronic device of claim 8, wherein the control component is configured to:

determine that said first housing member and said second housing member are configured in said closed position;

switch said external display device into a reflective optical state; and

switch said internal display device off.

13. The mobile electronic device of claim 8, wherein the said control component is configured to:

determine that said first housing member and said second housing member are configured in said open position;

switch said external display device into a transmissive optical state; and

switch said internal display device on.

14. The mobile electronic device of claim 12, wherein said external display device in said reflective optical state reflects light from said backlight through said external surface.

15. The mobile electronic device of claim 13, wherein said external display device in said transmissive optical state allows transmission of light from said backlight through said external display device to said internal display device.

16. The mobile electronic device of claim 12, wherein said internal display device is in a fixed color optical state when off, said fixed color optical state providing a contrast background for said external display device.

17. A method for providing visual information in a mobile electronic device, the mobile electronic device having an external display and an internal display, the method comprising:

switching said external display into a reflective optical state;

supplying light to said external display from a backlight;

reflecting light by said external display from said backlight;

switching said external display into a transmissive optical state; and

transmitting light from said backlight through said external display to said internal display.

18. The method as recited in claim 17, wherein switching said external display into a reflective state further comprises temporarily applying power to said external display.

19. The method as recited in claim 17, wherein switching said external display into a transmissive state further comprises temporarily applying power to said external display.

20. The method of claim 17 wherein switching said external display into a transmissive state further comprises switching said external display into a focal conic state and wherein switching said external display into a reflective state further comprises switching said external display into a planar state.