LASEREPAIR, Noritsu Laser Repair Service

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Instructions

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Brief explanation of matter:

Every Noritsu Laser unit includes three laser heads: 690 nm (RED), 532 nm (GREEN) and 473 nm (BLUE). RED is pure semiconductor laser, both GREEN and BLUE are DPSS (diode-pumped solid state) lasers. The basic principle of BLUE and GREEN DPSS lasers is SHG (second harmonic generation) process. BLUE and GREEN laser heads for Type A/A1 produced by Shimadzu, BLUE and GREEN laser heads for Type B/B1 produced by Showa Optronics. Type Ff is compromise between strong GREEN Showa (like in Type B1) and reliable BLUE Shimadzu (similar as in Type A1). RED laser heads are different from model to model depending of the year of design, because the technology always changes.

There are three AOM (acousto-optic modulator) next to each laser head. Exception is B110 Type Ff, where is only two AOMs (Red AOM is embedded into one device with RED laser), and B410/B540 Type Ff, where is only one GREEN AOM. AOMs are necessary to create the correct density of each exposed pixel. The principle of AOM is similar to attenuator - dimming the intensity of laser beam according to the input signal and based on BIAS preset determined by Initial Setup. AOMs are connected to AOM drivers situated outside of the laser unit. These are high frequency amplifiers. They get signal from Laser Control PCB. Noritsu calls them Signal Processors which does not reflect their entity, because the signal has been already "processed" by both Image Processing PCB and Laser Control PCB prior to AOM Driver. AOM's system is absolutely separate and does not connected to Laser Power system.

A number of lenses, mirrors and diaphragms are used to create a round spot of each laser beam and transfer them out of the unit, providing precise convergence and sharp focus at the right distance after the exit window for perfect quality exposure.

Polygon mirror assembly is a stepper motor rotating an octagonal mirror. Each facet transfers the continuous line of pixels into a horizontal sweep. Eight lines are printed per every full turn of Polygon mirror.

There are three synchronouos sensors in QSS 30 series laser units and LPS 24 PRO (only one in all other models). These are used to synchronize rotation speed of polygon mirror and the lines of pixels coming from AOM Drivers.

Specially coated mirror is used in all laser units except QSS 32, 34 and 37 series to turn the beam direction to 90 degrees (180 degrees in QSS 31 series laser units).

Laser unit is sealed device with no chance for dust to penetrate. Exit window is covered by specially coated glass. Uniformity of the exposure is very sensitive to the pieces of dust or hairs on this glass.

Laser Temperature control is based outside of the Laser unit. There are only four passive elements in Laser unit which must be connected to PCBs - two heaters and two thermosensors. One pair is for deck temperature control, second pair is for RED laser.

Tiny crystals are used in Laser heads. We can handle even such problems like on the picture below, when the crystal of doubler is broken.

Tiny crystals are used in Laser heads