Transparent display backlight assembly

• US 9,541,697 B2
• Filed: 06/09/2014
• Issued: 01/10/2017
• Est. Priority Date: 12/23/2010
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: Bohn, David D., Fleck, Rod G., Knee, Derek Leslie
• Primary Examiner(s): HAN, JASON
• Application Number:
  US14/299,859
• Publication Number:
  US 20140286047A1
• Time in Patent Office: 946 Days
• Field of Search: 362/601, 362606-607, 362/612, 362615-627, 349 62- 65, 349/69
• US Class Current: 1/1
• 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 the 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;

an active diffuser selectively configured to scatter the light from the light source 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 the 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 active diffuser is further configured to switch off to enable the section of the environment behind the backlight assembly to be viewed through the backlight assembly.

6. A backlight assembly as recited in claim 1, wherein the active diffuser is contained in an additional transparent display panel.

7. A backlight assembly as recited in claim 1, wherein active diffuser is further configured to uniformly illuminate the display panel.

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, the diffractive optics molded into the backlight panel;

or

negative prisms formed into the backlight panel, the negative prisms comprising nano-prisms configured to increase transparency.

9. A method implemented with a backlight assembly, the method comprising:

generating light with a light source in the backlight assembly;

directing the light from the light source with a backlight panel to illuminate a display panel of the backlight assembly, the display panel including a color filter system, and the backlight panel and the display panel each configured for a percentage of transparency that permits an environment behind the backlight assembly to be viewed through the backlight assembly;

scattering the light from the light source with an active diffuser that is selectively configured to scatter the light to prevent a section of the environment from being viewed through the backlight assembly; and

refracting the light from the light source with light refraction features to illuminate the display panel, the light refraction features spaced for a percentage of transparency that permits the environment behind the backlight assembly to be viewed through the backlight assembly.

10. A method 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 method as recited in claim 9, wherein the active diffuser is configured to switch off enabling the section of the environment behind the backlight assembly to be viewed through the backlight assembly.

12. A method as recited in claim 9, wherein the active diffuser is implemented in a transparent panel of the backlight assembly.

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

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

15. A method 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.

16. A method as recited in claim 9, wherein the light refraction features comprise negative prisms formed into the backlight panel, the negative prisms including nano-prisms configured to increase transparency of the backlight assembly.

17. A display device, comprising:

a touch screen configured for viewing an environment through the touch screen;

a backlight assembly configured for viewing the environment through the backlight assembly, the 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 the environment behind the backlight assembly to be viewed through the backlight assembly;

a backlight panel configured for a percentage of transparency that permits the 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;

an active diffuser selectively configured to scatter the light from the light source 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 the environment behind the backlight assembly to be viewed through the backlight assembly and to refract the light to illuminate the display panel.

18. A display device as recited in claim 17, wherein the light refraction features comprise light-scattering particles embedded in the backlight panel.

19. A display device as recited in claim 17, wherein the active diffuser is configured to switch off to enable the section of the environment behind the backlight assembly to be viewed through the backlight assembly.

20. A display device as recited in claim 17, 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, the diffractive optics molded into the backlight panel;

or

negative prisms formed into the backlight panel, the negative prisms comprising nano-prisms configured to increase transparency.