Precautions in the daily use of xenon lamps and mercury lamp
time: 2021-04-07 16:44 click:
1. Xenon lamp working principle
The xenon lamp is a high-voltage direct current gas discharge lamp, which is mainly composed of an electrode system (a cathode and anode), a quartz bulb, a metal alloy terminal and a xenon gas filled inside. The xenon lamp is either in a cold state or in a hot state during operation. There are ultra-high voltages inside, so explosion protection measures must be taken when contacting the xenon lamp in any case!
When working, the trigger first provides KV-level voltage for electronic triggering of the electrodes, and then the projector LPS will replace and provide a stable voltage/current for xenon lamp operation. The trigger voltage required for each xenon lamp is different, so the trigger of the machine is not universal. For example, the triggers required for DP2K-20C and DP2K-32B are different. And according to the power of the bulb, the number of lamp power supply groups equipped with the machine is inconsistent. The DP2K-S series is a set of lamp power supplies (2.5kV), the DP2K-C series is 2 sets of lamp power supplies (4.5kV), and DP2K/4K- 32B is the power supply for 3 groups of lights (7.5kV).
The stability of the power supply will have a greater impact on the operation of the xenon lamp. This is one of the reasons why the zero-ground voltage and the stability of the power supply need to be confirmed on site. For sites with unstable power supply, a voltage stabilizer needs to be installed.
2. Specification for the use of xenon lamps
When receiving the xenon lamp, it is necessary to confirm whether the outer packaging is intact, and there is no damage or extrusion deformation.
Before installation, you need to check the xenon lamp to see if there are debris, leaks, discoloration or other abnormal conditions inside the xenon lamp.
During installation, you need to wear protective measures to protect the personal safety of personnel. During the installation process, do not touch the position of the quartz bulb, because there is grease on your hands. Under high temperature operation of the xenon lamp, the grease will cause the quartz to appear partially whitened, thereby increasing the explosion. The risk of lights.
The brightest light-emitting point of the xenon lamp is at the top of the cathode, which is a point light source in the strict sense of the projector system. Therefore, after installing the xenon lamp, the optical axis needs to be calibrated so that the brightest point of the xenon lamp is at the focus of the reflector, so that the brightness output is optimized.
Calibrate the optical axis and collect the light through the reflective bowl, so that the brightest spot is located at the entrance of the engine light pipe. At this time, the brightness and uniformity of the screen are the best. If the bright spot is located inside the light pipe, the feedback will show a central bright spot on the screen, and the difference between the central brightness and the surrounding brightness is large, especially when a high-gain metal screen is used. This situation will be exacerbated; if the bright spot is located in front of the entrance of the light pipe, the feedback will be On the screen, the brightness of the screen is low, accompanied by flickering, because at this time the reflector is not reflecting the brightest point in the center of the bulb, but the position close to the anode surface. The light arc here is more important than the light arc at the center point. It is more unstable, especially in the later period of lamp use. More information related to this original text To view other translation information, you must enter the corresponding original text
Therefore, during the installation process, it is necessary to adjust the optical axis, which can make the theater get the best screen brightness and optimized brightness uniformity! Also during use, the brightness of the xenon lamp will decrease. On the one hand, the brightness of the xenon lamp can be increased by increasing the current of the xenon lamp. On the other hand, due to the loss of the cathode of the xenon lamp, the position of the bright spot will drift. At this time, the brightness can also be achieved by calibrating the optical axis. optimization.
Regarding the overtime use of xenon lamps, in principle, it is not recommended to overtime use, because the life time set by the lamp manufacturer is based on countless life tests. On the one hand, the lamp brightness will be reduced to more than 50% of the initial brightness when the life is reached. , From the viewing angle, the brightness at this time will greatly reduce the viewing experience. On the other hand, when the life is reached, the risk of the bulb exploding will be greatly increased. The quartz molecules of the bulb are in the glass state at the initial stage, and the light transmittance at this time Best, but with the use of the bulb, the quartz molecules will transform from the glass state to the solid state, and the light transmittance will also decrease, which will be converted into the heat inside the bulb. When the heat reaches an order of magnitude, the quartz bulb cannot withstand the corresponding The stress will blow up the lamp.
3. Working principle of mercury lamp
Ultra-high pressure mercury lamp, also known as UHP lamp, what is a mercury lamp? What are the differences compared with xenon lamps?
Like the xenon lamp, the mercury lamp is also a gas discharge lamp, but the xenon lamp uses an inert gas-xenon gas, and the mercury lamp uses liquid mercury. Secondly, the electrodes of the xenon lamp are divided into cathodes and anodes, which use direct current, while mercury lamps do not have the distinction of cathodes and anodes, and use alternating current. Therefore, the xenon lamp belongs to the high-voltage direct current gas discharge lamp, and the mercury lamp belongs to the high-voltage alternating current gas discharge lamp.
The mercury lamp is composed of a discharge tube, a reflector and a lamp holder. This is also different from the xenon lamp. The reflector bowl of the xenon lamp is independent and located inside the light box, and the position of the bright spot needs to be calibrated every time the bulb is installed for the best brightness and uniformity. The mercury lamp reflector bowl and the discharge tube are in the bulb. The manufacturer has already glued together when leaving the factory, so the position is at the best, no need to adjust!
Compared with xenon lamps, the visible spectrum of mercury lamps is also better, so it can fully present the color requirements of the film, but the current high-power mercury lamps can’t be compared with xenon lamps, so projector manufacturers usually use multiple sets in design For example, Barco’s DP2K-6E uses two sets of 460W mercury lamps and is equipped with specially designed color filters to make the colors meet the DCI requirements.
The discharge tube of the mercury lamp is filled with liquid mercury and related halogen gas. In the cold state, there is no high pressure inside. Only when the liquid mercury is converted into a gaseous state during operation, the high pressure will exist. Therefore, in the replacement of the bulb, the mercury lamp should be easy for the xenon lamp, just remove the corresponding light box and replace it directly. The mercury lamp will be equipped with an electronic rectifier, and the triggering and power supply of the mercury lamp are integrated!
4. Specification for the use of mercury lamps
Attention should be paid to the following points in the use of mercury lamps:
The ultraviolet light occupies a large proportion in the mercury lamp spectrum, so under no circumstances should it be exposed to the light source.
The mercury lamp should not be triggered frequently. In the cold state, the second trigger time is not less than 10 seconds, and in the hot state, the second trigger time is not less than 2 minutes. Turn off the mercury lamp to cool for at least 5 minutes each time until the fan speed drops. If you turn off the power of the projector directly after turning off the mercury lamp, the mercury lamp will not get sufficient cooling, and it will be difficult to light the lamp over time!
Mercury lamps have high requirements for temperature. Overheating or overcooling will have an adverse effect on the bulb. Overheating will cause the bulb to decay too quickly, thus failing to reach the specified use time; overcooling will make the internal halogen cycle incomplete, thus making The bulb is black and the brightness is not up to the requirement. Therefore, good and reasonable exhaust and heat dissipation are the prerequisite guarantee for the stable operation of the mercury lamp.
Because the inflatable body inside the mercury lamp is a dangerous substance, in the unfortunate event of a lamp blow, the personnel quickly evacuated the scene and ventilated for more than 15 minutes to clean up the debris and replace with a new lamp!
Do not dispose of old lamps at the end of their life, so as not to pollute the environment. Please contact the local qualified recycler for proper disposal!
