DISPLAY EFFICIENCY OPTIMIZATION BY COLOR FILTERING

• US 20150002528A1
• Filed: 06/28/2013
• Published: 01/01/2015
• Est. Priority Date: 06/28/2013
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: Bohn, David D., Nestorovic, Ned, Fleck, Rod G., Bell, Cynthia
• Granted Patent: US 9,664,905 B2
• Time in Patent Office: Days
• US Class Current: 345/589
• CPC Class Codes: G02B 2027/0112 comprising device for genereting colour display
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 5/18 Diffraction gratings holographic optical elements G02B5/32, G03H; integrally combined with optical fibres G02B6/02057; for coupling light guides G02B6/34; integrally combined with optical integrated light guides G02B6/12; grating systems G02B27/44
• CPC Class Codes: G02B 6/0076 Stacked arrangements of multiple light guides of the same or different cross-sectional area

Abstract

Technology is disclosed for optimizing a near-eye display using a waveguide. A first waveband for a first color narrower than the full spectral bandwidth for the first color and a second waveband for a second color adjacent to the first color in the visible spectrum are generated in image light of an image generation unit like a microdisplay. The first waveband and the second waveband are coupled into a same layer of a diffractive waveguide. An input grating of the same layer of the waveguide has a grating wavelength band approximately matching a waveband extensive with the first waveband and the second waveband. A converted green light emitting diode (LED) may be used for obtaining a first waveband centered around 515 nm in some examples. One of more of the wavebands may be obtained using filters, for example filters using dichroic mirrors, quantum dots or a combination of these.

Claims

1. A display system comprising:

a display;

one or more color waveband selective optical elements optically coupled to the display; and

an image generation unit, the image generation unit generating a first waveband for a first color which is narrower than a full spectral bandwidth for the first color and a second waveband for a second color.

2. The display system of claim 1 wherein the display system is a near-eye display system comprising:

a near-eye support structure;

the display is a near-eye display (NED) supported by the near-eye support structure, the near-eye display including a waveguide having a plurality of layers;

the image generation unit being supported by the near-eye support structure, the image generation unit including one or more light emitting diodes (LEDs) for emitting light;

the image generation unit generating image light from the light emitted by the one or more LEDs for the NED and the image light including the first waveband for a first color narrower than a full spectral bandwidth for the first color and the second waveband for a second color adjacent to the first color in a visible spectrum; and

the one or more color waveband selective optical elements includes a first input grating of one layer of the waveguide being optically coupled for receiving image light from the image generation unit and having a grating wavelength band approximately matching a waveband extensive with the first waveband and the second waveband for coupling light into the one layer.

3. The near-eye display system of claim 2 further comprising:

the first color is green, and the second color is blue, and the first waveband includes a lower portion of the spectral waveband of green, and is approximately centered about 515 nanometers(nm) and has a spectral width of about 50 nm.

4. The near-eye display system of claim 3 further comprising:

the waveguide having the plurality of layers has two layers;

the second waveband is approximately centered about 450 nm; and

the waveguide comprises a second input grating for coupling red image light approximately centered about 617 nm into a second layer of the two layers.

5. The near-eye display system of claim 2 further comprising:

the waveguide is a diffractive waveguide, and the input grating of the one layer is a surface relief grating.

6. The near-eye display system of claim 2 further comprising:

the one or more LEDs include a converted green LED.

7. The near-eye display system of claim 2 wherein the image generation unit further comprises at least one band filter for generating the first waveband for the first color from the light emitted by the one or more LEDs for the NED.

8. The near-eye display system of claim 6 wherein the at least one band filter includes a dichroic mirror.

9. The near-eye display system of claim 6 wherein the at least one band filter uses one or more quantum dots for converting light emitted by a blue LED of the one or more LEDs for generating the first waveband for the first color.

10. The near-eye display system of claim 6 wherein

the image generation unit includes a color filter liquid crystal on silicon (LCoS) display element having color filters;

and

the at least one band filter is implemented by at least one of the color filters using quantum dots for converting light emitted by the one or more LEDs to the first waveband.

11. A near-eye display system comprising:

a near-eye support structure;

a near-eye display (NED) supported by the near-eye support structure, the near-eye display including a waveguide having a plurality of layers;

the waveguide having an input grating for each of the plurality of layers, and at least one of the layers having an input grating having a wavelength band extensive with a waveband including a first waveband for a first color narrower than a full spectral bandwidth for the first color and a second waveband for a second color adjacent to the first color in a visible spectrum; and

the waveguide being optically coupled to an image generation unit supported by the near-eye support structure for receiving image light.

12. The near-eye display system of claim 11 further comprising:

the image generation unit;

one or more light emitting diodes (LED)s of the image generation unit including a converted green LED for emitting light of the first color including 515 nm; and

a filter of the image generation unit for passing the first waveband of about 50 nm centered about 515 nm for optical coupling by the input grating having the wavelength band extensive with the waveband including the first waveband and the second waveband.

13. The near-eye display system of claim 11 further comprising:

the image generation unit is a direct LED microdisplay including a converted green LED emitting a waveband including 515 nm; and

a filter for passing the first waveband of about 50 nm centered about 515 nm for optical coupling by the input grating having the wavelength band extensive with the waveband including the first waveband and the second waveband.

14. The near-eye display system of claim 12 wherein the filter is a band stop filter.

15. The near-eye display system of claim 12 wherein the filter is a band pass filter.

16. A method for optimizing waveguide performance in a near-eye display (NED) system comprising:

generating image light of at least three colors for a waveguide of the near-eye display (NED) by an image generation unit mounted on a near-eye support structure of the near-eye display system, the image light including a first waveband for a first color narrower than the full spectral bandwidth for the first color and a second waveband for a second color of the three colors adjacent to the first color in a visible spectrum; and

optically coupling the first waveband and the second waveband from the image generation unit into an input grating of one layer of the waveguide, the input grating having a grating wavelength band approximately matching a waveband extensive with the first waveband and the second waveband for coupling light into the one layer.

17. The method of claim 16 wherein the generating image light of at least three colors for a waveguide of the near-eye display (NED) by an image generation unit mounted on a near-eye support structure of the near-eye display system, the image light including a first waveband for a first color narrower than the full spectral bandwidth for the first color and a second waveband for a second color of the three colors adjacent to the first color in a visible spectrum further comprises

emitting light for the at least three colors by one or more LEDs of the image generation unit and narrowing the spectral bandwidth emitted for a first color to the first waveband which is spectrally closer to the second waveband for the adjacent second color.

18. The method of claim 16 wherein the generating image light of at least three colors for a waveguide of the near-eye display (NED) by an image generation unit mounted on a near-eye support structure of the near-eye display system, the image light including a first waveband for a first color narrower than the full spectral bandwidth for the first color and a second waveband for a second color of the three colors adjacent to the first color in a visible spectrum further comprises

emitting light by one or more LEDs of the image generation unit;

and

converting at least a portion of the emitted light to the first waveband which is spectrally closer to the second waveband for the adjacent second color.

19. The method of claim 18 wherein the one or more LEDs is a blue LED.

20. The method of claim 16 wherein the second color is blue and the first color is green, and the first waveband of the first color is approximately 50 nm centered around 515 nm, and the second waveband of the second color is approximately 50 nm centered around 450 nm.