As betrayed by the tube type number, the phosphor was green which was brighter for a given beam current that the contemporary white phosphors.
To achieve the required brightness, the tube was driven from a 25,000 volt accelerating supply. Because the picture had to be magnified to illuminate a screen that had about 100 times the area of the picture on the tube face, the image on the tube had to be very bright indeed. The tube was mounted vertically in the bottom of the cabinet with the screen pointing downward towards a concave mirror which reflected the image upward toward an angled mirror at the top of the cabinet onto the 25 inch screen, The top of the tube mirror box had a Schmidt lens to correct aberrations. It had not been appreciated at this time that a curved screen was optically better if the centre of curvature of the screen was in roughly the same place as the centre of curvature of the mirror. The tube size was dictated by the fact that it was the largest tube that could be made with a flat screen. The television back projected the image from a 4 + 1⁄ 2 inch tube onto a 25 inch etched celluloid screen sandwiched between two sheets of glass for protection. These had been the subject of an advertising campaign prior to the show which generated much interest. In 1937, both Philips and HMV put on display at the Radiolympia show in London, television sets that had a screen size of 25 inches based on the same MS11 Philips/Mullard tube. The early white phosphors were not as efficient as later offerings and these early televisions had to be watched in subdued lighting. The accelerating voltage used for these tubes was very low by later standards and even a twelve inch tube only ran from a 5000 volt supply. This necessitated a tube that was relatively long for its screen size. However, because the tube face had to be convex to provide resistance to air pressure, this mitigated the problem but only if the apparent deflection centre was more or less at the centre of curvature of the screen. The ability to correct the deflection signals for aberrations in tube geometry had not yet been developed, and it was necessary to make tubes that were relatively long compared with their screen size to minimise distortion.
#Sony projector tv parts driver#
The principal driver for the British government's move was to establish cathode ray tube production facilities which it believed would be vital if the anticipated World War 2 was to materialise.
In 1936, the British government persuaded the British Broadcasting Corporation to launch a public high definition (for the era ) television broadcasting service. Twelve inch tubes could be manufactured, but these were so long that they had to be mounted vertically and viewed via an angled mirror in the top of the cabinet. The largest practical tube that could be made that was capable of being mounted horizontally in a television cabinet of acceptable depth was around nine inches. Since the tube had to contain a very high vacuum, the glass was under considerable stress, together with the low deflection angle of CRTs of the era, the practical size of CRTs without increasing their depth was limited. It relied on conventional glass blowing methods largely unchanged in centuries. Background and history Necessity Ĭathode ray tube technology was very limited in the early days of television.
#Sony projector tv parts 1080p#
They are capable of producing high-definition content up to 1080p resolution, and examples include Sony's SXRD (Silicon X-tal Reflective Display), JVC's D-ILA (Digital Direct Drive Image Light Amplifier) and MicroDisplay Corporation's Liquid Fidelity. Newer technologies include DLP (reflective micromirror chip), LCD projectors, Laser TV and LCoS.
CRT rear-projection TVs were the earliest, and while they were the first to exceed 40", they were also bulky and the picture was unclear at close range. Three types of projection systems are used in projection TVs. A variation is a video projector, using similar technology, which projects onto a screen. Until approximately 2006, most of the relatively affordable consumer large screen TVs up to 100 in (250 cm) used rear-projection technology. Rear-projection television ( RPTV) is a type of large-screen television display technology. Mid-2000s RPTV with HDTV tuner and YPbPr input as well as DVI (digital) video inputs.
0 kommentar(er)
