Transparent display backlight assembly

• US 8,770,813 B2
• Filed: 12/23/2010
• Issued: 07/08/2014
• Est. Priority Date: 12/23/2010
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Bohn, David D., Fleck, Rod G., Knee, Derek Leslie
• Primary Examiner(s): HAN, JASON
• Application Number:
  US12/977,852
• Publication Number:
  US 20120163021A1
• Time in Patent Office: 1,293 Days
• Field of Search: 362/601, 362606-607, 362/612, 362615-627, 349 62- 65, 349/69
• US Class Current: 362/601
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02B 6/0033 Means for improving the coupling-out of light from the light guide
• CPC Class Codes: G02B 6/0035 provided on the surface of the light guide or in the bulk of it
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0041 provided in the bulk of the light guide
• CPC Class Codes: G02B 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02B 6/0076 Stacked arrangements of multiple light guides of the same or different cross-sectional area
• CPC Class Codes: G02F 1/133342 for double-sided displays
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: G02F 1/133622 Colour sequential illumination
• CPC Class Codes: G02F 2203/01 transmissive
• CPC Class Codes: Y10S 977/834 Optical properties of nanomaterial, e.g. specified transparency, opacity, or index of refraction

Abstract

In embodiments of a transparent display backlight assembly, a backlight panel is operable as a transparent panel, and a light source generates light that the backlight panel directs from the light source to illuminate a display panel of a display device. Light refraction features refract and scatter the light, where the light refraction features are spaced for approximate transparency of the backlight panel and to illuminate the display panel. An active diffuser can be implemented as an additional transparent panel and operable for activation to diffuse the light from the backlight panel that illuminates the display panel.

Claims

1. A backlight assembly, comprising:

a light source configured to generate light;

a display panel including a color filter system and configured for a percentage of transparency that permits an environment behind the backlight assembly to be viewed through the backlight assembly;

a backlight panel configured for a percentage of transparency that permits an environment behind the backlight assembly to be viewed through the backlight assembly and configured to direct the light from the light source to illuminate the display panel;

a multi-mode panel of the backlight assembly comprising an active shutter that provides variable light transmissivity based at least in part on an applied voltage and configured to prevent a section of the environment from being viewed through the backlight assembly; and

light refraction features configured to refract and scatter the light, the light refraction features spaced for a percentage of transparency that permits an environment behind the backlight assembly to be viewed through the backlight assembly and to refract the light to illuminate the display panel.

2. A backlight assembly as recited in claim 1, wherein the light source comprises one or more arrays of light emitting diodes (LEDs), and the backlight panel is edge-lit by the one or more arrays of LEDs.

3. A backlight assembly as recited in claim 1, wherein the light source comprises a first array of light emitting diodes (LEDs) proximate a first edge of the backlight panel, and further comprises a second array of LEDs proximate a second edge of the backlight panel.

4. A backlight assembly as recited in claim 1, wherein the light refraction features comprise light-scattering particles embedded in the backlight panel.

5. A backlight assembly as recited in claim 1, wherein the light refraction features comprise micro extraction features formed as hemisphere divots into the backlight panel.

6. A backlight assembly as recited in claim 1, wherein the light refraction features comprise diffractive optics configured to refract designated light wavelengths, the diffractive optics molded into the backlight panel.

7. A backlight assembly as recited in claim 1, wherein the light refraction features comprise negative prisms formed into the backlight panel, the negative prisms comprising nano-prisms configured to increase transparency.

8. A backlight assembly as recited in claim 1, wherein the light refraction features comprise a combination of light-scattering particles embedded in the backlight panel and at least one of:

micro extraction features formed as hemisphere divots into the backlight panel;

diffractive optics configured to refract designated light wavelengths;

or

negative prisms formed into the backlight panel.

9. A transparent display, comprising:

a display panel including a color filter system and configured for a percentage of transparency that permits an environment behind the display panel to be viewed through the display panel;

a light source configured to generate light;

a backlight panel operable as a transparent panel and configured to direct the light from the light source to illuminate the display panel, the backlight panel including light refraction features spaced for a percentage of transparency that permits an environment behind the backlight assembly to be viewed through the backlight assembly and configured to refract and scatter the light to illuminate the display panel; and

a multi-mode panel comprising an active reflector including a dual-state mirror having a transparent state for transparency and a reflective state to reflect and recycle light and configured to prevent a section of the environment from being viewed through the display panel.

10. A transparent display as recited in claim 9, wherein the light source comprises one or more arrays of light emitting diodes (LEDs), and the backlight panel is edge-lit by the one or more arrays of LEDs.

11. A transparent display as recited in claim 9, wherein the light refraction features comprise light-scattering particles embedded in the backlight panel.

12. A transparent display as recited in claim 9, wherein the light refraction features comprise micro extraction features formed as hemisphere divots into the backlight panel.

13. A transparent display as recited in claim 9, wherein the light refraction features comprise diffractive optics configured to refract designated light wavelengths, the diffractive optics molded into the backlight panel.

14. A transparent display as recited in claim 9, wherein the light refraction features comprise negative prisms formed into the backlight panel, the negative prisms comprising nano-prisms configured to increase transparency.

15. A method, comprising:

allowing an environment to be viewed through a display panel of a display device;

generating light with a light source;

refracting the light with light refraction features spaced for a percentage of transparency that permits an environment behind the display device to be viewed through the display device;

illuminating the display panel with the refracted light; and

preventing a section of the environment from being viewed through the display panel with a multi-mode panel of the display device comprising an active shutter that provides variable light transmissivity based at least in part on an applied voltage.

16. A method as recited in claim 15, wherein the light is generated with one or more arrays of light emitting diodes (LEDs), and the backlight panel is edge-lit by the one or more arrays of LEDs.

17. A method as recited in claim 15, wherein the light is refracted with the light refraction features that comprise light-scattering particles embedded in the backlight panel.

18. A method as recited in claim 15, wherein the light is refracted with the light refraction features that comprise micro extraction features formed as hemisphere divots into the backlight panel.

19. A method as recited in claim 15, wherein the light is refracted with the light refraction features that comprise diffractive optics molded into the backlight panel and configured to refract designated light wavelengths.

20. A method as recited in claim 15, wherein the light is refracted with the light refraction features that comprise negative prisms formed into the backlight panel, the negative prisms comprising nano-prisms configured to increase transparency.