Major TV Manufacturer Utilizes MTI’s Laser System To Improve Quality Control - MTI Instruments - #1

Text version of the page

MTI Instruments, Inc. 325 Washington Avenue Extension Albany, NY 12205 PH: +1-518-218-2550 OR USA TOLL FREE: 1-800-342-2203 FX: +1-518-218-2506 sales@mtiinstruments.com www.mtiinstruments.com APPLICATION NOTE Major TV Manufacturer Utilizes MTI’s Laser System To Improve Quality Control Introduction As more consumers expect the best possible picture quality, increased demands are being placed on manufacturers to ensure that their products offer the highest performance, are uniform from one TV set to another, and that broadcast signals are faithfully reproduced. This is even more relevant in today’s marketplace due to the increased proliferation of HDTV sets, home theaters and the public’s expectation of a superior overall “theater-like” viewing experience. The Problem Rear Projection TV makers require that the CRT gun project a clear and crisp image on the front TV screen for optimum television viewing enjoyment. The CRT/front screen combination must be kept in precise alignment with each other under all possible extremes of temperature and humidity. Without proper alignment, parts of the picture image can appear blurry, or otherwise distorted. A consistent and repeatable method was needed to ensure that the viewing screen position did not shift under temperature extremes of from -10 C to 40 C and with humidity as high as 95%. A system was needed to sense the small relative movement between the front viewing screen and a fi xed location on the TV housing. Since any standard contact device could affect the readings, a noncontact sensor would be required for this application. The Solution MTI Instruments’ proven Microtrak 7000 Series Dual Channel Laser was selected for the task. The system can be easily confi gured to make relative motion measurements. Laser #1 senses screen position and Laser #2 measures a fi xed reference point on the TV screen front housing. Within the Microtrak controller a subtracted, or “difference” signal derived from both readings is obtained. This signal represents the amount of movement, or shift in the position of the front screen, before and after exposure to temperature and humidity swings as the TV set passes through an environmental chamber. Since the viewing screen is transparent and the Microtrak 7000 laser requires an opaque target, a small temporary white adhesive paper target was affi xed to the screen. This target ensured that the maximum amount of signal was refl ected back to the laser head and resulted in data with the highest possible accuracy and repeatability. MTII appnote: televisionqc.pdf - Page 1 of 2