How to make the xenon lamp achieve the best use effect
time: 2021-04-07 17:00 click:
The high-pressure short-arc xenon lamp for digital projectors is generally referred to as a digital xenon lamp, which is a typical high-pressure gas discharge lamp. Because the characteristic spectral curve of xenon is almost the same as that of natural light, it is the best choice for digital projectors to restore and express natural colors. But in order to achieve the best use effect of the digital xenon lamp, it is also necessary to pay attention to its correct use method. 1. About brightness
1. Attention to the use environment
The brightness output value of the digital projector is the remaining value of the light output of the digital xenon lamp after passing through a series of filters, DLP, DMD, color filters and lenses. If the measurement point is in the projection hall, the loss of light output from the projection window needs to be considered. Based on a lot of practical experience, we found that the cleaning and maintenance of DLP is the most critical part of maintaining the brightness output of digital projectors. The impact of cleaning on the brightness greatly exceeds the difference in light output of different digital xenon lamps. Of course, the degree of cleanliness of the reflector, filter, lens and projection window will also have a certain impact, especially if the material of the projection window is not selected optical glass, the overall light output will decrease proportionally (the light transmittance of general optical glass At around 98%, the light transmittance of ordinary white glass is lower than 90%).
2. Methods to slow down the attenuation of digital xenon light output
Light output attenuation is a phenomenon that inevitably occurs when digital xenon lamps and even all light sources are in use. In addition to the difference in the attenuation rate caused by the difference in the manufacturing process of the light source itself, the degradation of the material used in the light source is also an unavoidable situation. Correct use can effectively reduce the degradation rate of the material itself, thereby reducing the rate of light output attenuation. Including ensuring the proper ventilation of the lamp room (too small ventilation will cause the overall lamp to overheat and accelerate the degradation of the light transmittance of the lamp housing. At the same time, high temperature will also reduce the structural strength of the digital xenon lamp sphere, increasing the risk of "light explosion"; Excessive ventilation will cause the local temperature of the sphere of the digital xenon lamp to be too low, resulting in a "cold trap effect", causing local blackening of the lamp body, affecting light transmission, and increasing the "stress" on the surface of the sphere, which will also increase "The risk of blasting the lamp".); Choose the appropriate initial working power (the loss rate of the metal parts of the digital xenon lamp is shown as a gradually slowing curve, with a certain linear law. The excessive initial loss will directly affect The subsequent decay rate for the entire life cycle).
Second, reduce the failure rate
1. Inspection before the digital xenon lamp on the machine
Although every Yuyu digital xenon lamp has undergone strict quality inspections from production to delivery and uses considerable transportation safeguards, this does not rule out the situation that the lamp body is still damaged during transportation. Generally speaking, before the new lamp is put on the machine, it is necessary to check with safety protection measures (hood, gloves and protective clothing) whether the following conditions exist:
There are obvious scratches on the surface of the sphere
Cracks on the sphere
There are glass debris inside the sphere (metal debris with a diameter less than 0.5 does not affect the quality of the lamp)
There are colored lines on the surface of the sphere
Once you find the above situation, you need to stop using the lamp, and contact the manufacturer to replace the new lamp, otherwise there will be a great chance of failure.
2. Power adjustment
The issue of power selection in the initial use of new lamps has already been mentioned above. What needs to be added is:
Nowadays, most theaters need to switch between 2D and 3D movies. Because 3D movies have higher requirements for brightness, in general, theaters will set different powers for the two channels. For example, the 2D channel uses 75% and the 3D channel uses 95% of the power, and frequently switches (switching several times in a day). This situation will cause irregular wear of the metal parts inside the lamp, and these losses are irreversible. With the increase of time, it will eventually cause the phenomenon of "drifting arc" which seriously affects the quality of the projection, and greatly increases the probability of light explosion.
Our suggestion is that the difference between the two different settings should not be too large, generally control at about 15%, and minimize the frequency of switching between each other.
3. Clean the environment of the lamp room
The temperature of the surface of the sphere is extremely high when the digital xenon lamp is working, and any solid or liquid with a larger volume will cause the lamp to blow up when it is working. Therefore, when the lamp is working, it is necessary to ensure that the air inlet filter of the lamp room can work normally, and it must not be removed to avoid debris being sucked into the vent. At the same time, considering that the digital exhaust system of many theaters is shared with the mall where it is located, it has to be considered whether there will be foreign objects falling from the exhaust vent into the light room (many occur when the theater is turned off the projector This is the cause of the light explosion). In the case that the exhaust system cannot be changed, effective preventive measures include choosing corrugated rather than straight-shaped ventilation ducts, and ensuring that the ducts have a certain curvature (under the condition that the ventilation is not affected, a shallow U-shape is the best); Do not turn off the exhaust air before cooling completely to prevent sudden pressure loss in the lamp room.
4. Fixing of the lamp
The fixation of the cathode and anode at both ends of the xenon lamp is very important: First, prevent the contact area between the lamp and the device from being too small. When the lamp is working (generally greater than 100 amperes), a large amount of resistance heat is generated at the contact location, causing the xenon lamp or the device to malfunction. Second, prevent the "drift arc" of the xenon lamp caused by the vibration of the equipment (not only the arc drift of the digital xenon lamp caused by the jitter, but also the abnormal electrode loss, and finally the "drift arc" of the lamp itself) .
Another thing to note is that some cathode-triggered xenon lamps, such as NEC’s dedicated digital xenon lamp, have a metal lead on the cathode (not the "trigger wire" wound on the lamp body). It is necessary to ensure that the distance between the metal lead and the inner wall of the lamp is large enough, because when the xenon lamp is "ignited", the lead has a trigger voltage of tens of thousands of volts through. If the lead wire discharges to the metal on the inner wall of the lamp chamber, it will cause the lamp to trigger and not light up, and at the worst, cause the lead wire and the inner wall of the lamp chamber to melt or equipment failure.
Digital xenon lamp plays a vital role in movie projection. The rational use of digital xenon lamp to improve the light utilization rate and use efficiency of xenon lamp to make full use of it has practical significance for the operation of digital cinema and also effectively improves the quality of projection. An important method to prolong the service life of xenon lamps.
