Measurement of Speckle Size in Laser Display

This paper introduces the laser speckle in laser display system and autocorrelation function to measure the speckle size. What's more, it develops a new method to calculate the speckle size. It firstly thresholds the speckle image into binarization image. Then it calculates the statistical average of run-length of the speckle in a given direction. This statistical average of run- length can describe the speckle size precisely. Finally, it draws a conclusion that the new method is much easier for hardware implementation comparing with that by autocorrelation function. Keywords-laser display; laser speckle; run-length; autorrelation function A new generation of display technology with the represent of laser display is urging an international revolution in the display industry. Experienced from the stages of black& white display, color display and digital display, display technology has stepped into a new era. And laser display is one of the most promising display technologies. Compared with the traditional display technologies, Laser display technology has many advantages. Its color gamut can be easily beyond of NTSC (e.g., 166%), while traditional display's color gamut can be merely up to no more than 50% of NTSC. Because the laser display take RGB lasers as the primaries. The spectrum width of lasers is no more than 3 nm, which is far less than that of LED, CRT, PDP, etc. Just because of this unique trait, except for bigger color gamut, some other advantages emerge, for example, long lifetime, no warm-up time, less noise and power consumption, high contrast ratio, etc(1)-(3).