Liquid crystal display assembly with phosphorescent backlighting

• US 4,641,925 A
• Filed: 03/20/1986
• Issued: 02/10/1987
• Est. Priority Date: 03/20/1986
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Richardson, C. Patrick, Gasparaitis, Bernard V.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Gallivar, Richard F.
• Application Number:
  US06/841,988
• Time in Patent Office: 327 Days
• Field of Search: 350/345, 250/458.1, 250/463.1
• US Class Current: 349/68
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: G02F 1/133617 Illumination with ultraviolet light; Luminescent elements or materials associated to the cell

Abstract

A backlighted liquid crystal display (LCD) assembly has a thin phosphorescent layer positioned between the display and the light source to provide an even distribution of light intensity across the viewing surface of the display. The phosphorescent layer includes a phosphor powder mixed into a resin. The mixture is molded into a thin sheet and then cut to size. The phosphorescent layer and an optional disiccant layer may be encapsulated between sheets of acrylic film. The phosphorescent layer may also include a phosphorescent coating that is applied to the rear surface of the LCD or to the front surface of the light source.

Claims

1. A display assembly, for use with a supplemental light source, said display assembly comprising in combination:

a display; and

thin phosphorescent layer having front and rear surfaces, said front surface positioned adjacent said display, whereby light is emitted into said display from said front surface when said rear surface is illuminated by said light source.

2. The display assembly of claim 1, further comprising a phosphorescent assembly having front and rear clear protective layers respectively adjacent said front and rear surfaces of said thin phosphorescent layer, wherein the bordering surfaces of said front and rear protective layers are joined together, thereby encapsulating said thin phosphorescent layer.

3. The display assembly of claim 2, further comprising a thin transparent desiccant layer located between said front and rear clear protective layers.

4. The display assembly of claim 2, wherein the joined bordering surfaces of said front and rear protective layers are flange shaped.

5. The display assembly of claim 2, further comprising a clear adhesive between said display and said front protective layer to attach said display to said phosphorescent assembly.

6. The display assembly of claim 2, further comprising a clear adhesive attached to said rear protective layer for attaching said phosphorescent assembly to said light source.

7. The display assembly of claim 1, wherein said thin phosphorescent layer includes a mixture of silicone rubber and phosphorescent material.

8. The display assembly of claim 1, wherein said thin phosphorescent layer includes a mixture of plastic and phosphorescent material.

9. The display assembly of claim 1, wherein said thin phosphorescent layer includes a phosphorescent coating.

10. A liquid crystal display assembly, comprising in combination:

a liquid crystal display;

a thin phosphorescent layer having front and rear surfaces, said front surface positioned adjacent said display; and

a light guide adjacent said rear surface of said thin phosphorescent layer for backlighting said display, said light guide having at least one light source;

whereby, light is emitted from said front surface of said thin phosphorescent layer into said display when said rear surface is illuminated by light from said light guide.

11. The liquid crystal display assembly of claim 10, further comprising front and rear sheets of film respectively adjacent said front and rear surfaces of said thin phosphorescent layer, wherein the edges of said front and rear protective films are joined together, thereby encapsulating said thin phosphorescent layer and forming a phosphorescent assembly.

12. The liquid crystal display assembly of claim 11, further comprising a thin transparent desiccant layer located between said front and rear protective films.

13. The liquid crystal display assembly of claim 11, wherein the joined edges of said front and rear protective films are flange shaped.

14. The liquid crystal display assembly of claim 11, further comprising a clear adhesive between said display and said front film and between said rear film and said light guide.

15. The liquid crystal display assembly of claim 10, wherein said thin phosphorescent layer includes a molded mixture of silicone rubber and a phosphorescent powder.

16. The liquid crystal display assembly of claim 10, wherein said thin phosphorescent layer includes a molded mixture of clear thermoplastic and a phosphorescent powder.

17. The liquid crystal display assembly of claim 10, wherein said thin phosphorescent layer includes a phosphorescent coating.

18. A liquid crystal display assembly, comprising in combination:

a transflective liquid crystal display;

a clear front protective film positioned behind said display;

a thin phosphorescent layer having front and rear surfaces, said front surface positioned behind said front film;

a clear rear protective film positioned behind said thin phosphorescent layer, the edges of said front and rear films being joined so that said thin phosphorescent layer is encapsulated between said front and rear films; and

a light guide positioned behind said rear protective film, said light guide having at least one light source;

whereby, light is emitted from said front surface of said thin phosphorescent layer into said display when said rear surface is illuminated by light from said light guide.