EuropMirror Specification FSM-ED-002

1.0 PURPOSE & SCOPE
This specification defines the quality and Performance criteria for Front Surface Mirror (FSM) products on glass Substrates in stock sheet or finished part form, either with or without a protective tape.

2.0 REFERENCE DOCUMENTS
The following documents form a part of this specification to the extent specified herein:

Mirror, Front Surfaced Aluminized; for Optical Elements
Environmental Test Methods
Coating, Single or Multi-layer, Interference: Durability Requirements

3.0   PRODUCT SPECIFICATION
Front Surface Mirrors (FSM) are designed to meet selective reflectance requirements over the Visual spectrum.

3.1   Optical/Spectral Characteristics
Spectral reflectance Performance of the front surface mirror coating at a 45 degree angle inside the clear aperture shall meet the following minimum values in the visible spectrum as follows:

3.2   Standard Products
The specular reflectance for unpolarized light of each of the following Standard products shall meet or exceed the listed minimum reflectance values.

3.4 Environmental Durability

Adhesion:
The coating shall show no damage after 3M Scotch Brand No. 600 tape is pressed firmly against the coated surface and removed quickly by a snap of the wrist, according to EuropTec document.
Abrasion Resistance:
The mirror coating shall show no damage after a 200-rub test with a cheesecloth pad approximately 9,5 mm & 454g, according to EuropTec document.
Humidity Resistance:
The coating shall show no deterioration after exposure to a 24 hour humidity test (49 degrees C, 95% relative humidity) according to EuropTec document
Corrosion Resistance:
The coating shall show no deterioration after a 24-hour exposure to salt fog (5% NaCI by weight) at 35°C per EuropTec document.

3.5 Surface Quality Characteristics (Viewing Conditions)
View at 30-60cm with overhead lighting to observe front surface at 100 foot-candles of fluorescent illuminations (daylight conditions). Bottom lighting to observe pinholes of 100 foot-candles of diffused fluorescent illumination. Ambient lighting 30-50 foot-candles. Top and bottom observation time 30 to 35 seconds. Viewing angle can ränge from 0-75 degrees.

3.5.1   Scratches (cut parts)
Scratches shall not exceed 0.06mm in width, nor accumulate in length more than Vi the mean diameter of the part. Disregard all scratches less than 0.02mm in width.

3.5.2   Scratches - Stock Sheets
Since a broad ränge of part sizes can be cut from stock sheets, all stock sheets are evaluated on the basic assumption of a final part size of 125mm x 150mm. In this case, a maximum accumulated scratch length of 50mm is allowed within any 125mm x 150mm area of the stock sheet.

A maximum scratch width of 0.06mm will be allowed.
A scratch less than 0.03mm in width shall be disregarded.

3.5.3   Voids, Spatter, Digs and Foreign Matter (cut parts & stock sheets)
This section pertains to defects that are approximately circular in appearance. The effective dimension of noncircular defects shall be determined by averaging the length and width of the defect. Defects shall not exceed the following limits:

Maximum defect diameter: 0.4mm
Minimum distance between two 0.4mm defects: 19mm
Disregard defects less than 0.05mm
Defects that penetrate the coating and are less than 0.4mm shall have accumulated diameters less than 0.8mm in any 19mm circle of surface area.
Defects which do not penetrate the coating and are less than 0.4mm shall have accumulated diameters less than 1.6mm in any 19mm circle of surface area.

3.5.4 Chips and Fractures (cut parts and stock sheets)
The cumulative length of all glass Chips in the ränge 0.25 - 2.2mm is not to exceed 10% of the perimeter.

No Chips shall exceed 2.2mm
Disregard Chips <0.25mm
Unterminated fractures are not allowed.

3.5.5   Flakes (cut parts only)
The cumulative length of all flakes (voids in the coating around the perimeter generated by the cutting process) which extend less than or equal to 1.5mm into the coated surface, is not to exceed 10% of the perimeter.

3.5.6   Stains
No stains allowed which are readily visible to the unaided eye when viewed under inspection conditions. Viewing conditions are: View at 30-60cm with overhead lighting to observe front surface at 800 Lux of fluorescent illuminations (daylight conditions). Bottom lighting to observe pinholes of 800-1000 Lux of diffused fluorescent illumination. Top and bottom observation time 30 to 35 seconds. Viewing angle can ränge from 0-75 degrees.

3.5.7   Useable Area
Individual stock sheets shall have a minimum useable area of 90% when the sheet is cut into parts 125mm x 150mm. (For example, a minimum of 43 out of 48 5"x6"parts shall be good on the large stock sheet.) Typical yields are in excess of this value. Yields are dependent on part sizes and will generally increase for smaller-sized parts.

4.0       PHYSICAL SPECIFICATION
4.1      Thickness
Glass Substrate is available:

4.2.2 Cut Parts
When parts are cut from stock sheets by EuropTec, a Standard manufacturing tolerance of ±0.8 mm is to be allowed.

Special tolerance requirements will be quoted upon request.
Standard manufacturing methods provide clean-cut (Sharp) edges. Seaming to reduce Sharp edges can be provided upon request.

4.3 Flatness
Flatness of the glass Substrate, on which the mirror coating is deposited, is Standard commercial grade soda lime glass. Applications where flatness is more critical will be quoted on request.