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Difference between revisions of "Philips MHN-TD"
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The lamp technology was an improvement of previously developed mercury vapour lamps. The potential for fluorescent powders was mostly exhausted by early 70s which meant that research concentrated on releasing better lamps that produced light directly from the discharge tube. This research was also carried previously but results were modest, as stable compounds with good colour reproduction were found to be quite aggressive and lead to short service life. Sodium, Scandium, Indium, Thallium were attempted as main elements that can offer a balanced light output but they required a specific balance of temperature and pressure to achieve best results. One major limitation was that certain compounds were costly or difficult to manufacture or mix in specific amounts, which meant that suitable results could not be found for many decades. In the late 70s and early 80s most major manufactures were able to center on specific technologies that reached good enough results for general lighting, with predictable performance. | The lamp technology was an improvement of previously developed mercury vapour lamps. The potential for fluorescent powders was mostly exhausted by early 70s which meant that research concentrated on releasing better lamps that produced light directly from the discharge tube. This research was also carried previously but results were modest, as stable compounds with good colour reproduction were found to be quite aggressive and lead to short service life. Sodium, Scandium, Indium, Thallium were attempted as main elements that can offer a balanced light output but they required a specific balance of temperature and pressure to achieve best results. One major limitation was that certain compounds were costly or difficult to manufacture or mix in specific amounts, which meant that suitable results could not be found for many decades. In the late 70s and early 80s most major manufactures were able to center on specific technologies that reached good enough results for general lighting, with predictable performance. | ||
The MHN-TD range was the result of research aimed at creating lower powered metal hallide lamps that had better colour reproduction and energy efficiency compared with high pressure mercury vapour lamps. The most important limiting factor was that the arc tube had to be formed more evenly at the ends and be reasonably well insulated and heat resistant to ensure reasonable performance. More advanced manufacturing tools and processes had to be developed. | The MHN-TD range was the result of research aimed at creating lower powered metal hallide lamps that had better colour reproduction and energy efficiency compared with high pressure mercury vapour lamps. The most important limiting factor was that the arc tube had to be formed more evenly at the ends and be reasonably well insulated and heat resistant to ensure reasonable performance. More advanced manufacturing tools and processes had to be developed. The arc tube was well built to resist the long term corrosive nature of hallides. It was also important to ensure less variations in arc tube geometry as well as temperature profile. This meant that heat reflecting coatings were mandatory for the arc tube. As soon as all these conditions were met, the lamp was released. Products were quite successful on the market until the advent of the much improved ceramic tube metal hallide lamps, around mid 1990s. Although Philips CDM lamps were much more expensive, their better colour reproduction, lamp life and efficiency meant that there was no reason, other than cost, to choose MHN lamps. | ||
The only improvement on MHN-TD lamps focused on slightly improved colour reproduction which required higher operating pressure and slightly changed chemistry to ensure stability in this environment to reach color rendering indexes Ra8 of more than 80. Philips was not interested to invest more in quartz metal hallide technology so other world manufacturers like General Electric, Osram and others quickly surpassed it with better performing products so Philips competed only mostly on cost and ensured its market-share with advertising. Even before the advent of LEDs MHN-TD lamp installations were pointless so sales were mostly based on the large install base created in the 1990s. | The only improvement on MHN-TD lamps focused on slightly improved colour reproduction which required higher operating pressure and slightly changed chemistry to ensure stability in this environment to reach color rendering indexes Ra8 of more than 80. Philips was not interested to invest more in quartz metal hallide technology so other world manufacturers like General Electric, Osram and others quickly surpassed it with better performing products so Philips competed only mostly on cost and ensured its market-share with advertising. Even before the advent of LEDs MHN-TD lamp installations were pointless so sales were mostly based on the large install base created in the 1990s. | ||