User Guide

RH-51/52, RH-67/68 Company Confidential

6(a) - Baseband Troubleshooting Nokia Customer Care

Figure 38: Effects of dust in optical path

If large dust particles get trapped on top of the lens surface in the cavity between cam-

era window and lens, they will cause image blurring and poor contrast (see also item

‘sharpness’). The seal between the window and lens should prevent any particles from

getting into the cavity after manufacturing phase.

If dust particles are found on the sensor or are suspected to be inside the camera mod-

ule, this is classified as a manufacturing error of the module and thus the camera should

be replaced. The particles inside the cavity between window and lens have most probably

been trapped there in the assembly phase in the factory. It is of course also possible that

the user has disassembled the device and caused the problem. However, in most cases it

should be possible to remove the particle(s) by using compressed air. Never wipe the lens

surface before trying compressed air; the possibility of damaging the lens is substantial.

Always check the image sharpness after removing dust.

Testing for sharpness

If pictures taken with a device are claimed to be blurry, there are four possible sources

for the claim:

• The user has tried to take pictures in too dark conditions and images are blurred due

to handshake or movement. No need to replace camera module.

• There is dirt between the back window and camera lens.

The back window is defective. Window should be changed.

• Back window is visibly scratched, broken or dirty.

• Camera lens is misfocused.

Quantitative analysis of sharpness is very difficult to conduct in other than optics labo-

ratory environment. Thus subjective analysis should be used.

If no visible defects (items 2-4) can be found, a couple of test images should be taken

and checked. Generally, a well illuminated typical indoor office scene, such as the one in

Figure “A good quality picture taken indoors”, can be used as a target.