User Guide

• Laser-marked serial numbering on PWB (for versioning)

• Passive components

• Camera protection window; part of the phone cover mechanics

• Dust gasket between the lens unit and camera protection window

Image quality analysis

Testing for dust in camera module

Symptoms and diagnosis

For detecting dust problems, take an image of a uniform white surface and analyse it in full resolution. A

good quality PC CRT monitor is preferred for analysis (avoid using LCD). Search carefully because finding these

defects is not always easy. Figure "Effects of dust on optical path" is an example of an image having easily

detectable dust problems.

When taking a white image, use uniformly lightened white paper or white wall. Another option is to use

uniform light but in this case make sure that the camera image is not flickering when taking the test image.

In case flickering occurs, try to reduce the illumination level. Use JPEG image format for analysing, and set

the image quality parameter to ‘High Quality’.

Black spots in an image are caused by dirt particles trapped inside the optical system. Clearly visible and

sharp edged black dots in an image are typically dust particles on the image sensor. These spots are searched

for in the manufacturing phase, but it is possible that the camera body cavity contains a particle, which may

move onto the image sensor active surface, for example, when the phone is dropped. Therefore it is also

possible that the problem will disappear before the phone is brought to service. The camera should be

replaced if the problem is present when the service technician analyses the phone.

If dust particles are lying on the infrared filter surface on either side, they are hard to locate because they

are out of focus, and appear in the image as large, grayish and fading-edge 'blobs'. Sometimes they are

invisible to the eye, and the user probably does not notice them at all. However, it is possible that a larger

particle disturbs the user, causing need for service.

Figure 78 Effects of dust on optical path

If large dust particles get trapped on top of the lens surface in the cavity between the camera window and

the lens, they will cause image blurring and poor contrast. If dust stays on the camera module surface, camera

cussion, camera bezel or window at assembling, dust may sneak into the optical system as the optical zoom

or Auto focus lens moves back and forth. The camera cussion and bezel between the window and the lens

unit or camera module should prevent any particles from getting into the cavity after the manufacturing

phase.

RM-10;RM-24

Nokia Customer Care Camera Module Troubleshooting

Page 8 –12 COMPANY CONFIDENTIAL Issue 1