cleaning CCD chip cover glass

 

  1. Keep it clean in the first place!

    Prevent the unit from being exposed to dusty, dirty and otherwise abnormal conditions-- to the extent that is possible and reasonable. When the back is not attached to a camera, keep the CCD glass covered with the supplied cover plate. Treat it as you would a very expensive lens.
  2. Blow it off.

    Use a rubber squeeze bulb to blow dust and debris from the glass surface. Very little dust will become adhered to the glass surface. Furthermore, the air from the bulb is the same temperature and humidity as ambient conditions. Do not use the "canned air" units as they often spit drops of unvolatilized liquid which leave difficult-to-remove marks when the drops evaporate. In addition, the temperature of the gas (or liquid) emitted is very cold and can cause thermal shock and possible cracking of the glass. It is especially important not to attempt the cleaning of camera mirrors or the cover glass of the chip with the "canned air". Blowing out the camera interior with the same rubber squeeze bulb is recommended.
  3. Brush it off.

    Use a sable or camel's hair brush-dedicated to that purpose and kept physically protected in a clean, storage container. If there are particles that refuse to be budged by air from the blower, the next most desirable approach is to use a very soft bristled brush and then, no more intensively or often than is necessary. Sable or camel's hair brushes in several styles and storage containers are available from photo supply outlets and art supply stores. One recommended form is the "lipstick tube" style that has a tube cover which, when removed, allows the bristles to extend when the tube bottom is rotated. Any such soft-bristled brush, kept clean, will fulfill the condition to clean using the lowest pressure and softest material against the glass.
  4. Optical Wipe Packets.

    Despite the user's best efforts to protect and keep the glass clean, events beyond normal control may result in the deposition of matter on the glass surface that will not be blown or brushed off. As a "last resort", it may become necessary to use a solvent and absorbent fabric to remove foreign material. Heavy pressure and the transferrance of skin oil are to be avoided. With the proper precautions and techniques, lens tissue and lens cleaner fluid may be used successfully, but the strong tendency of lens tissue to shed lint is quite hard to overcome. Furthermore, as lens cleaning fluid is an excellent oil solvent, an excess of fluid quickly wicks up to the fingers and dissolves skin oil which promptly diffuses through the porous tissue and is transferred then to the surface being "cleaned". Replacing solid matter with a thin coating of skin oil is not generally found to be an attractive swap. More recent technology offers a better alternative. Originally developed as lint-free wiping materials and totally volatile solvents for clean room use, pre-soaked packaged wipes are available for use in cleaning high-grade optical surfaces. The pre-moistened units are easy to use and will retain their effectiveness for long periods if the packet is not penetrated. Typically, the pack is torn open and the pre-wetted material removed. The wipe is shaken open and, with an effort to minimize skin contact, gathered to make a pass, in one direction, over the glass surface. If additional swipes are needed, the previously used area is folded in and an additional swipe taken; repeated as necessary. Extra care must be taken to
    1. avoid wiping with parts of the pad that have contacted the skin, and
    2. avoid wiping with a previously used area.

 

Observing this hierarchy of:

  1. Avoiding exposure of the Chip to dirty environments,
  2. Blowing dust particles away,
  3. Brushing away with a soft brush, and
  4. Contacting lightly with solvent saturated pads,

will conserve the factory condition of the critically important Glass Cover/Filter. Please contact MegaVision Tech Support if additional information is needed.

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