Technical / Research

There's an interesting post over at Optics.org discussing new green laser solutions shown at this year's Photonics West meeting. One of the hottest applications for such lasers are pico-projectors.

Spectralus Corporations microchip laser

Spectralus Corporation is showing one of the smallest devices with a volume of just 0.4 cm³. It's a microchip laser, meaning that the diode-pumped Nd:YVO₄ laser crystal and the nonlinear crystal are monolithically assembled into a single, tiny microchip. What is unique about the Spectralus laser is the use of periodically poled, MgO-doped lithium niobate as the doubling crystal, instead of the KTP that is commonly used in microchip green lasers.

Two other papers, from authors at the Ferdinand Braun Institute in Berlin, Germany, at the Danish Technical University (DTU) in Roskilde, and at the Fraunhofer Institute for Laser Technology (ILT) in Aachen, Germany, reported the use of periodically poled MgO-doped lithium niobate as well, but in less compact designs.

Back in June 2009, we reported that Apple has been awarded an iPhone pico-projector patent. A month later it was reported that they are actually working on such a device. Today we learn that Apple has filed a new projector related patent, that appears to be describing their work on a few different types of projection systems as opposed to a single projector system. This pico-projector can be integrated into a dedicated remote controller or in a client device (iPhone, iPod, laptop, etc.).

Apple pico-projector patent diagram March 2010

Via PatentlyApple

Display Photonics Systems (DPS) is a new start-up that has developed a new single-panel projection technology called Angular Color Projection (ACP). They claim that their solution is more efficient, brighter, smaller and cheaper than current solutions. DPS has already been granted some patents and created a fully working prototype. They are now seeking funding to complete product development and create a pilot production line in China.

ACP technology diagram

Here's how they describe the technology: RGB images are displayed side by side simultaneously on a single microdisplay panel and proprietary projection lens converges the RGB images to a full color image. At a certain plane within the projection lens, RGB color lights are distributed (encoded) at different angles. A set of dichroic mirrors are then used to converge RGB lights.

ACP can be used with an HID lamp, White LED, RGB LED or laser. The technology allows for future migration to OLED based (self emitting) projectors.

Check out this beautiful demo of Light Blue Optics' 10" Light-Touch projector:

Here's how their Holographic Laser Projection (HLP) technology works.

Microsoft Research is showing their new 'Mobile Surface', which is a projected touch display. This is very similar to LBO's light-touch product announced at CES:

Photodigm is a US based company, developing and producing precision lasers since 2000. They are now starting to address the pico-projector laser market. But Photodigm has a different approach then other laser companies.

They say that commercial green lasers today are made using frequency doubling of readily available near infrared lasers. However, the most efficient approach is complex and expensive. The cheapest approach is inefficient, resulting in short battery life. On the horizon are native green lasers, but the materials system for them is devilishly complex, and low yields and high costs threaten to keep these out of consumer products for years.

Convinced that the industry was on the wrong track, Photodigm explored the problem from the ground up. They concluded that the green laser is not the problem. The RGB module is.  Working from their core technology of precision near infrared lasers, Photodigm has developed a technology that promises to deliver a module that is cheap, efficient, scalable, and compact.

Photodigm are currently in talks with several strategic partners from the consumer side, in order to commercialize the technology. They believe that their pico-projector laser modules might be available at around 2011. We'll keep watching ;-)

Carnegie Mellon University and Microsoft are working together on touchscreens for your body, called Skinput. The idea is to combine pico-projectors that project on your skin with special armband containing piezoelectric cantilevers - sensors that can measure pressure, acceleration and force - which know which part of your body was pressed based on the sound it made (on the skin, muscle or skeleton).

This is all rather weird and cool - it can be used for gaming, or text inputting for your mobile phone. Check out this interesting video: