Apple Developing Hybrid Laser Projection Displays

Apple - Stardust Correction - 450x 250y


On March 31, 2011 the USPTO published patent application 20110075055 assigned to Apple, Inc titled, Display System Having Coherent and Incoherent Light Sources.  The inventor describes some of the issues with existing projection systems using coherent light sources (i.e. laser) as the following:

 

[0004] Electronic devices are ubiquitous in society and can be found in everything from wristwatches to computers. Many of these electronic devices include the ability to display images to the user of the electronic device, such as by projecting the displayed images through a lens onto a screen or backdrop. Conventional projectors include so called "laser projectors," which render images using coherent laser light as opposed to projectors using incoherent incandescent light sources. While the laser display systems may offer greater resolution than non-laser based display systems, they often consume greater amounts of power. Because of their greater power consumption requirements, laser based display systems also may include complicated cooling circuitry and thus result in more bulky projection equipment.

[0005] Another issue with laser display systems versus non-laser based display systems is the so called "speckle" problem. "Speckling" refers to an interference in the intensity of highly coherent light, such as laser light, which may result from the laser striking a rough surface. The overall effect of speckle in laser display systems is that the image may appear grainy. Furthermore, laser light sources are often more costly than other non-laser light sources, making laser based display systems more expensive. Accordingly, display systems that embrace the desirable features of laser light sources while overcoming the undesirable features of non-laser light sources may be useful.

 

As a means for addressing these issues, Apple has developed methods for combining coherent and incoherent (e.g. LED) light sources.  They describe the advances as such:

 

[0006] Embodiments are disclosed that allow light display systems, such as projectors, to have lower power consumption, reduced speckling, and/or that are less expensive than conventional light projectors. In some embodiments, an incoherent light source may be optically coupled to a coherent light source to produce a combined coherent and incoherent beam of light for projecting images. In general, incoherent light sources, such as light emitting diodes (LEDs) or incandescent bulbs, emanate light waves across a broad spectrum (e.g., multiple wavelengths of light), whereas coherent light sources, such as lasers, are more precise and emanate light waves of a single wavelength. By combining light from the incoherent light source with the light from the coherent light source, the overall power level of the coherent light source in the combined light beam may be reduced while still perceiving a crisp, clear image. As a result of the lower power levels for the coherent light sources, the size and complexity of light projection systems may be reduced.


[0007] Some embodiments may take the form of a system for displaying images, wherein the system includes an incoherent light source and a coherent light source operating in concert with the incoherent light source to produce a combined beam of light, where the combined light beam includes similar wavelength contributions from the incoherent and coherent light sources. The term "operation in concert" as used herein is intended to refer to the coherent and incoherent light sources emanating at least one wavelength that is substantially the same at substantially the same time.

[0008] Other embodiments may take the form of a method of calibrating an image display system, wherein the method includes the operations of providing an image to one or more display circuits, setting a first intensity level for an incoherent light source, determining if an intensity of the projected image equals a desired intensity level, and, in the event that the intensity of the projected image does not equal the desired intensity, setting a second intensity level for a coherent light source.

[0009] Still another embodiment may be a method of projecting an image, wherein the method includes separating an image into first and second components, projecting the first component using an incoherent light source, and projecting the second component using a coherent light source, wherein the incoherent and the coherent sources concurrently generate similar wavelengths to render the image.

 

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Apple is taking an interesting approach toward improving the display performance of laser-based projection displays.  The combination of less-coherent light sources with laser-based light sources can improve speckle performance, while reducing overall power consumption.  Applications for this include traditional large-format projection, embedded projection, as well as for rear projection applications (such as televisions).  Apple does not discuss any preferred method for generating the individual pixels of the image.  Therefore, it appears that the patent application is broad enough to cover DLP, LCoS, or scanned mirror displays.

 

This is exciting news for projector-philes.  We’ve heard speculation of Apple products with embedded projection capability in recent months.  Could this be the beginning of additional filings for projector-enable iPod, iPad, and iPhone devices?  We’ll be sure to keep our eye on this.  Meanwhile, check out the full patent application below.

Archived Comments....

I guess we have our answer when the patent was originally dated 30th sept 2009. There were no reasonable quantities of SGL's around, and DGL's were still a dream. If there were green lasers in 2009, Apple would've had embedded pico projectors in their idevices, they are waiting for DGL's now, it's that simple. Pico projectors will be huge, but with LED's incorporated there was no way any manufacturer would embed them when the user has to manually focus.

There are DLP-based projector phones on the market.  They have been limited thus far, but I belive that has more to do with brightness than need to focus.

 

Ultimately, the market will decide which features are most important.  It will be very interesting, indeed, to monitor how things evolve.

 

 

Paul

Paul Marganski

Co-founder and Contributor

Email: paul@picopros.com

Twitter @pmarganski

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laser doesn't need focus. Autofocus of the LED would use the same techniques as autofocus cameras, it would check frequently to find the distance to the target surface and adjust the LED focus accordingly.

That's a good point.  Wonder if an auto-focus feature could be packaged into an embeddable design, such as the laptop they depict in the application?

 

I like the observation.

 

Paul

Paul Marganski

Co-founder and Contributor

Email: paul@picopros.com

Twitter @pmarganski

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How can that even be patentable? The patent system disgusts me, patenting things before they even make them so they can make patent portifolio. Darn patent trolls.

This is merely a patent application. It could take years to get any claims from this, if any. I think your use of the term patent troll is a little off base. Anyhow, it can take a long time to get claimclaims accepted and I assure you that the USPTO does a thorough job analyzing applications.

Paul

Paul Marganski

Co-founder and Contributor

Email: paul@picopros.com

Twitter @pmarganski

www.picopros.com

 

Paul,

 

Was this patent not filed on September 30, 2009 and granted on March 31, 2011?

 

Does this not mean it was filed when companies such as Osram, Nichia and Soraa had just begun working on direct green lasers?

The dates you indicate are accurate. Though I am not exactly sure when those companies started working on direct green lasers.

Paul

Paul Marganski

Co-founder and Contributor

Email: paul@picopros.com

Twitter @pmarganski

www.picopros.com

 

Doesn't the LED need to be focused/refocused with projection distance?  How do you get around this?  Would they just limit projection distance/range and use a lens that keeps the image focused within that range?

 

I was trying to understand that myself. Perhaps the lasers allow for less need to focus. Particularly,if they are just replacing one color of the RGB source. Paul

Paul Marganski

Co-founder and Contributor

Email: paul@picopros.com

Twitter @pmarganski

www.picopros.com

 

Great stuff
I wonder if this is a simple solution to the green laser supply problem? Just replace the green SGL or DGL (which won't be available in Apple quantities for a while) with a green LED. I mean this patent doesn't take into account the size restraints that incorporating both lasers and LEDs would encounter, and only by swapping a laser for an LED would this be viable. Paul C

I was thinking this, but didn't want to speculate.  The application does not lock them into having full RGB for both the LEDs and lasers, so it could encompass this concept.

 

Still not sure it is patentable.  Pretty neat though!

Paul Marganski

Co-founder and Contributor

Email: paul@picopros.com

Twitter @pmarganski

www.picopros.com

 

In the end, Apple may quite possibly throw-in with Microvision.  They seem to be trying to reinvent the wheel.  Microvision is light years ahead of the micro laser projection development curve.

I wonder how patentable this application is, really.  Does it overcome the "obviousness" requirement for patent?  Combining laser and LED light sources is not all that unique.

 

In the end, it is interesting that Apple is playing around with the idea of embedded projection, nonetheless.

 

Paul

Paul Marganski

Co-founder and Contributor

Email: paul@picopros.com

Twitter @pmarganski

www.picopros.com