Problems and solutions of laser light source

With the development of 4K/3D/laser projection/high frame rate/LED light source, coaxial audio and other technical hotspots, mainstream projector manufacturers have successively launched their own laser projector products in the first half of 2014. This has made laser light sources a hot topic. The topic, how far can the laser go, what are the problems with the laser light source, how did these problems be solved in the process of applying them to the construction of the theater? Technology Dr. Sun Xiaobin's technology sharing content got some answers. 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, which is called laser speckles (Laser Speckles). ) Or markings. How to solve the problem of laser speckle at present: Method 1. Screen vibration interference The vibration of the film screen by a low-noise vibration motor is used to eliminate the granular speckle of the screen under the high-intensity light source, so that the color of the image reflected by the film screen can be seen It 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 factor of speckle is in the environment of green light (green laser) wavelength, the removal of speckle is achieved by interfering with the green 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. • What is a 3P laser projector: The image on the screen is an image created using the three primary colors of red, green and blue (RGB). Through the external polarization 3D system, the left-eye picture and the right-eye picture are separated, and the pictures are played cyclically 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 groups of 3P light sources, and 2 groups 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 purchase and maintenance costs of glasses are high. Current status of laser technology development