The solution to the speckle problem of laser light source
The discussion process on the laser speckle problem mentioned two concepts:
What is speckle? Speckle phenomenon is common in the process of optical imaging. Because of the high coherence of laser, the phenomenon of laser speckle is more obvious.
What is laser speckle? When the laser is diffusely reflected from the surface of the scatterer or passes through a transparent scatterer (such as ground glass), a random distribution of bright and dark spots can be observed in the scattering surface or the light field nearby, called laser speckles (LaserSpeckles) Or markings.
How to solve the problem of laser speckle:
Method 1. Screen vibration interference
The vibration of the film screen by the low-noise vibration motor eliminates the granular speckles of the screen under the high-intensity light source, so that the color of the image reflected by the film screen looks natural and full, with uniform brightness and clear picture.
Features: The laser light source has high photoelectric conversion efficiency, the laser module has low heat dissipation requirements, and the screen vibration mechanism is a mechanical device, which is intuitive and simple to maintain.
Method 2. Laser wavelength interference
Because the main cause of speckle is in the environment of green light (green laser) wavelength, the removal of speckle is achieved by interfering with the green light wavelength and decomposing the continuous wavelength of green light.
Features: It is still in the stage of output in the laboratory, the photoelectric conversion efficiency of the multi-wavelength green laser module is extremely low, the heat is high, and the risk of thermal fatigue of the device due to poor heat dissipation is high. Generally, the 21-meter giant screen shows that the power of its multi-wave green laser projection equipment can be as high as more than 12,000 watts, while the Fuzhou cineLab laser giant screen is only more than 4,000 watts.
After solving the technical problems, the technology sharing explained the problems from the perspectives of 3P and 6P, which made us more aware of the development status of laser projectors.
The image on the screen is an image created using the three primary colors of red, green, and blue light (RGB). Through the external polarization 3D system, the left-eye image and the right-eye image are separated, and the images are played in a loop to form a 3D effect.
What is a 6P laser projector:
The image on the screen is a 6-primary-color laser projection system using 2 sets of 3P light sources and 2 sets of red, green, and blue light synthesis (R1G1B1 and R2G2B2). There is no need to separate the loop images of the left and right eyes, but the 3D images of both eyes are played at the same time. 3d light efficiency is high. The disadvantage is that the weight of chromatographic 3D eyes is significantly higher than that of polarized 3D eyes, and the cost of glasses purchase and maintenance is high. As we all know, a reasonable choice of laser projection system and suitable 3D equipment can solve most of the 3D brightness problems of metal screens.
