Unico SQ Series, Service Manual, Page: 32 / 96

Optical
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4. Optical System
The optical system of SQ series Spectrophotometers are adopted littrow type
with 1200lines/mm grating, UV-2800, UV-2802,UV-2802PC, UV-2802S and
UV-2802PCS are Single Beam, the optical system schematic diagram are shown in
4.1. UV-3802 and UV-4802 are Split Beam and Double Beam, the optical system
schematic diagram are shown in 4.2 and 4.3.
4.1
Incidence of Light
The neutral light coming from the Tungsten lamp or the Deuterium lamp is
focused at the entrance slit of the monochrometer by the concave mirror.
4.2
Dispersion of Light
The light passed through the entrance slit , reflected by the collimating mirror
to analytical grating. The light is spectrally dispersed by the grating and reflected
collimating mirror to the exit slit.
4.3
Exit of Light
4.3.1 Exit of the Single Beam (UV-2800, UV-2802(S), UV-2802PC(S))
The light from the exit slit, through the condenser lens focused on the
sample, continue pass through the sample, the light finally to the
photodetector. Shown in Figure 4.1.
4.3.2 Exit of the Split Beam (UV-3802)
From the exit slit, the light was separated two path by the mirror, the main
light focused on the sample after it passed though the condenser lens,
continue pass through the sample, the light finally to the photodetector on the
main Amplifier PCB. The slave light passed though the condenser lens to the
photodetector on the Slave Amplifier PCB. Shown in Figure 4.2.
4.3.3 Exit of the Double Beam (UV-4802)
From the exit slit, the light was separated two paths by the mirror, the main
light focused on the sample after it passed though the condenser lens,
continue pass through the sample, the light finally to the photodetector on the
main Amplifier PCB. The slave light focused on the 2nd exit slit in the slave
light path, then focused on the reference after it passed though the slave
condenser lens, continue pass through the reference, the light finally to the
photodetector on the slave Amplifier PCB.
Shown in Figure 4.3.