Display cell having active and passive areas

• US 5,130,827 A
• Filed: 09/10/1990
• Issued: 07/14/1992
• Est. Priority Date: 09/10/1990
• Status: Expired due to Term

• Current Assignee: Moog Incorporated
• Original Assignee: Litton Systems Incorporated
• Inventors: Bruce, Alan G., Guthrie, Charles L., Pavone, Frank D.
• Primary Examiner(s): Hille, Rolf
• Assistant Examiner(s): TRAN, MINH LOAN
• Application Number:
  US07/579,616
• Time in Patent Office: 673 Days
• Field of Search: 350/334, 350/336, 350/345, 350/343, 350/331 R, 350/339 D, 350/339 R, 350/339 F, 340/784
• US Class Current: 349/68
• CPC Class Codes: B60K 2370/154 Combined instruments with analogue meters and additional displays
• CPC Class Codes: B60K 35/215 characterised by the combination of multiple visual outputs, e.g. combined instruments with analogue meters and additional displays
• CPC Class Codes: G01D 7/00 Indicating measured values
• CPC Class Codes: G02F 1/133374 for displaying permanent signs or marks

Abstract

An LCD has both active and passive display areas. The active areas are presented by selective energization of dichroic liquid crystal, and the passive areas are created by a mask. The LCD cell includes a sealed cavity containing the dichroic liquid crystal which has an area substantially less than the total display area. The remaining portion of the LCD cell is free of liquid crystal and is transparent to the passage of light from a rear light source.

Claims

1. A display having both active and passive areas comprising:

a front glass and a rear glass;

a first sealed cavity formed between the front glass and rear glass, the first sealed cavity being filled with liquid crystal material and defining an active area which is substantially less than the total area of the display;

electrode means for selectively energizing the liquid crystal material;

a second cavity formed between the front glass and rear glass, the second cavity being free of liquid crystal material and defining a passive area which is a substantial portion of the total viewing area of the display;

a mask on the passive area having indicia thereon, the mask comprising cutout areas in registration with the first sealed cavity and an opaque material having light transmissive areas which form the indicia in registration with the second cavity; and

a light source behind the rear glass, whereby the active area of the display is varied by selective energization of the liquid material, and whereby the indicia on the mask is illuminated by the light source.

2. The display of claim 1 further comprising:

a lamp and a transflector comprising the light source.

3. The display of claim 1 further comprising:

clear areas and colored areas comprising the light transmissive areas of the mask, whereby the passive area of the display is in plural colors.

4. The display of claim 3 wherein the mask is located adjacent the front glass.

5. The display of claim 3 wherein the mask is located between the rear glass and the transflector.

8. The display of claim 1 wherein the mask is positioned on the front glass.

9. The display of claim 8 wherein the indicia are clear.

10. The display of claim 8 wherein the indicia are translucent and colored.

11. The display of claim 8 wherein some of the indicia are clear and some are colored.

12. The display of claim 8 further comprising:

a selected pattern of electrodes in the first sealed cavity in registration with the cutout areas of the mask; and

a plurality of conductive traces on the front and rear glass each having one end coupled to one of the electrodes and another end located at the periphery of the front and rear glass, wherein some of the conductive traces are in alignment with the light transmitting areas comprising the indicia.

13. The display of claim 1 wherein the mask is positioned on the rear glass between the rear glass and the transflector.

14. The display of claim 13 wherein the indicia are clear.

15. The display of claim 13 wherein the indicia are translucent and colored.

16. The display of claim 13 wherein some of teh indicia are clear and some are colored.

6. The display having both active and passive areas comprising:

an LCD cell comprising a front glass and a rear glass;

a seal bead between the front glass and rear glass;

a first sealed cavity formed by the seal bead, the first sealed cavity being filled with liquid crystal material and defining an active area which is substantially less than the total area of the display;

a second cavity between the front glass and rear glass, the second cavity being free of liquid crystal material and defining a passive area of the display;

a mask having light transmitting indicia thereon in registration with the second cavity;

cutout areas on the mask in registration with portions of the first sealed cavity; and

illumination means positioned behind the LCD cell, whereby the light transmitting indicia on the mask is illuminated by the illumination means.

7. The display of claim 6 further comprising:

a transflector and a light source positioned behind the transflector comprising the illumination means.