， 来不及翻译，只当学E文。 希望对大家尤其是激光
亮点：4K DMD; 600W, 55000流明; 对比度2300:1。
对散斑的报道让人琢磨不透 --- 个人观点而已，见仁见智，请大家客观地分析吧：） IMAX, Barco and Kodak to Bring Laser Cinema
Last time I did a Display Daily column on laser cinema was back when IMAX announced they had licensed the Kodak laser cinema technology. But, neither IMAX nor Kodak actually builds projectors. Now the other shoe has dropped with announcements by Barco and IMAX that Barco has been chosen to be the exclusive supplier of projectors for IMAX for the next 7 years. According to the announcement, the laser projectors will incorporate technology IMAX has licensed from Kodak.
This 7-year agreement covers both xenon lamp-based projectors and laser projectors. Previously, Christie had supplied the IMAX xenon projectors, so this is a big feather in its cap for Barco. IMAX may not be a huge market itself, but it is certainly a very visible one. The first xenon-based IMAX projectors are expected to be installed by mid-2012. Installation of Barco laser projectors at IMAX venues will begin in 2013.
In January, Barco demonstrated a laser projector with an eye-popping 55,000 lumens. See the February issue of Large Display Report for details on that demonstration. Here are some additional technical details of the demonstration that were not available in time for the February LDR:
- 600 optical watts of laser power (Total R+G+B)
- Laser light is coupled to the existing integration rod in a conventional DP 4K-32B optical core.
- 1.38-inch DLP 4K DMD with an illuminated area is 4096 X 2160 pixels was used.
- Contrast of 2,300:1
- The wide color gamut of the laser was mapped to a standard digital cinema P3 color gamut for the demo.
- Everything was self-contained in one projector cabinet 30" wide X 36" high X 60" long (76 x 91 x 152 cm). This includes the lasers and the laser drivers.
- A standard projection lens was used, with no optical modifications done on the output side of the DLP optical core.
- The demo was shown on a 70 foot (21.3M) wide Harkness matte screen (1.0 gain) at a light level of 22fL. 22 fL on a gain 1.0 screen area of 2,560 sq. ft. (238M2), corresponds to 56,980 Lumens.
- Pictures were excellent, with especially good uniformity and resolution across the full screen.
- There was no observed chromatic aberration in the image.
- By all reports, speckle was not an issue. Even experienced observers could not see speckle in color bars showing the P3 color gamut. When color bars showing the full laser gamut were shown, the speckle in the green bar was visible although still not objectionable. Barco acknowledges speckle is objectionable on a silver screen for 3D, however.
- A retrofit program for existing digital cinema projectors is thought to be necessary by Barco, and product development is including that option.
- The demonstration was not a product yet.
- Barco listed the challenges as:
o Regulatory issues
o Retrofit design issues to allow the lasers to replace an existing xenon lamp and power supply
o Speckle on a silver screen.
It is not clear how much Kodak technology was incorporated into the projector used for Barco's January demonstration. For that matter, it is not clear how much of the Kodak technology will be incorporated into the laser projectors IMAX and Barco will introduce in 2013. The Kodak technology is based on design of an entirely new projector, not a retrofit into a xenon projector and is not intended for retrofit applications. While it is certain some aspects of Kodak technology will be incorporated, since Barco feels the retrofit market is important, aspects of the Kodak technology that depend on a new projector design may be bypassed for now.
One key question about the demonstration: Whose lasers were used? Speculation centers on NECSEL lasers, but IMAX, Barco and NECSEL have not confirmed this. One advantage of using NECSEL lasers is that the large number of emitters needed would significantly reduce speckle. Insight Media estimates that 1400 separate emitters would be needed for NECSEL to product the required green wattage. Since speckle is reduced by Square Root(N) in a system like this, 1400 emitters would reduce the speckle by roughly a factor of 37x. While additional speckle reduction may be needed, this would be a giant first step in speckle reduction. One thing about speckle is not clear: how low a level is required for digital cinema? Projectors with xenon lamps are not speckle free but are considered good enough. This certainly helps define thetarget for IMAX, Barco, Kodak and the laser supplier.