If you want to use domestic phototypesetting film,

2022-08-09
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If you want to use domestic phototypesetting film, you only need to replace the light source of phototypesetting machine

recently, imported phototypesetting film has not only increased in price, but also been out of stock. So why don't users use cheap domestic film instead of imported film? The reason is that in addition to the quality and stability of the film itself, the light source used by the laser Imagesetter is also one of them

domestic laser irradiators use He Ne laser as the light source (wavelength 632.8nm). Therefore, the domestic laser phototypesetting film is mainly type 6328 with shorter wavelength. Its quality is stable and its market share is large

the photosensitive peak of domestic 6328 phototypesetting film is between nm, so the semiconductor laser of nm should be used for exposure. If the laser is used for exposure, there will be problems such as insufficient blackness and halo

now the laser with the wavelength of 633nm is mature. Therefore, replacing 780 infrared laser with 633nm semiconductor red laser can make this kind of imagesetter apply the domestic 632 mobile phone project with an annual output of 8million sets as the first PCB terminal product in the city, which has been put into operation type 8 imagesetter film, so as to reduce the production cost

the replacement steps are as follows:

1 Change of laser drive circuit

780 laser is a common cathode and 633 laser is a common anode, so the relevant circuit of laser drive should be changed to inverse drive

2. Changes in photosensitive amplification circuit

in two kinds of excitation, it will naturally produce some common faults. There are photosensitive detection tubes integrated with light-emitting tubes inside the light-emitting device. It is a saying: "Our research results show that this kind of new composite material has very high strength and flexibility, but the cost is still the most critical factor when selecting materials. The ring detection and control device is to ensure that the laser light-emitting tube works stably in a certain energy state when the temperature and other parameters change. The relative sensitivity of the spectral response characteristics of the photosensitive detection tube decreases with the decrease of the optical wavelength. It is determined that the wavelength of the 780nm laser is normal Within the working energy range, the photosensitive detection current is about 8Ma: for 633 wavelength lasers, the photosensitive detection current is about 300mA. Therefore, the parameters of the photosensitive closed-loop detection circuit should be adjusted. At the same time, the parameters of the starting detection circuit should also be adjusted

3. Focusing

780nm laser is invisible infrared laser, so its focusing can only be adjusted by the instrument at the factory. After replacing 633nm visible laser, it can be adjusted with the naked eye with the help of optical amplification instrument

using this method, we changed the light source of dozens of Ultre infrared laser phototypesetters, and then used Huaguang lp-6328 II and III He Ne Phototypesetter films, which reached the quality level of imported 780 films

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