Glass Filter Catalogue
43Pages

Glass Filters 2009 Definitions

4 OPTICAL FILTERS FOREWORD Foreword SCHOTT’s optical filter glass catalog is the source of choice for system designers and optical engineers to devise solutions for optical applications for a wide variety of market needs. SCHOTT’s filter program has been expanded to make it the most comprehensive and reliable source in the world. Now our portfolio contains special bandpass filters for NVIS applications (S-8022 and S-8023) and the high performance bandpass filter S-8612, e.g. as IR-cut filter for CMOS applications. All of our filter datasheets and the filter calculation program can be easily...

5 OPTICAL FILTERS GENERAL INFORMATION ON THE CATALOG DATA 1. General information on the catalog data All data listed in this catalog not containing tolerances are to be understood as reference values. Guaranteed values are only those values listed in the data section of the catalog under ”Limit Values of i“, ”Tolerance Ranges of i“ and ”Tolerances for Longpass Filters“. The graphically depicted internal transmittance curves serve as an initial overview to aid you in finding the most suitable filter type for your application. Unless otherwise indicated, all data are valid for a temperature...

6 OPTICAL FILTERS SCHOTT GLASS FILTER CATALOG: PRODUCT LINE 2. SCHOTT glass filter catalog: product line The filter glass product line of SCHOTT comprises the following filter types in the wavelength range above 200 nm: Bandpass filters, that selectively transmit a desired wavelength range, Longpass filters, that block an undesired shorter wavelength range, Shortpass filters, that block an undesired longer wavelength range, and Neutral density filters, that exhibit nearly constant transmission, especially in the visible range. Filter glass is manufactured and supplied in different...

7 OPTICAL FILTERS APPLICATIONS FOR SCHOTT GLASS FILTERS 3. Applications for SCHOTT glass filters All glass filter types can be used as substrates for thin film coating to fabricate interference filters. Thus the specific advantages of the individual components (absorption properties of optical glass filters and the reflection properties of interference coatings) can be combined in one optical filter. SCHOTT has a wide range of thin film coating capabilities, so that in nearly every case an optimal filter solution according to special customer’s requirements can be offered. Optical glass...

8 OPTICAL FILTERS APPLICATIONS FOR SCHOTT GLASS FILTERS The RG filters (such as RG780, RG830, and RG850) which appear black to the eye, serve for the separation of visible radiation and infrared radiation. While they almost totally absorb the visible radiation, the highest possible levels of the longer wavelength infrared radiation can pass through the filter. There are many sensor applications in the near infrared region, where undesirable visible radiation can distort measurements or even make them impossible and must therefore be totally eliminated. An additional area where the RG filter...

9 OPTICAL FILTERS APPLICATIONS FOR SCHOTT GLASS FILTERS BG39 and the high performance filter glass S-8612 are suited for electronic cameras (CCD or CMOS). A special application for a bandpass filter is covered by the NVIS compatible glasses. These glasses have a certain color with a small radius of tolerance. Additionally, their optical density is high for wavelengths that are usually enhanced by night-vision equipment.

10 OPTICAL FILTERS MATERIAL: FILTER GLASS 4. Material: filter glass Our filter glass types contain no more than 0.05 weight percent thorium oxide or other radioactive material. Negligible inherent radioactivity can be present as in many everyday substances as a result of the natural radioactivity of raw materials. 4.1 Group names Filter glasses are distinguished by more or less selective absorption of optical radiation. The filters only appear colored if their filter action is within the visible spectral range. Our filter glasses are classified into the following groups: UG Black and blue...

11 OPTICAL FILTERS MATERIAL: FILTER GLASS 4.2.3 Colloidally colored glasses The colorants in these glasses are in most cases rendered effective by a secondary heat treatment (”striking“) of the initially (nearly) colorless glass. Particulary important glasses in this class are the yellow, orange, red, and black filter glasses with their steep absorption edges. As with the ionically colored glasses, their color is dependent upon the type and concentration of the colorants, the base glass, and, to a large extent, their thermal history during the secondary heat treatment (see GG, OG and RG...

12 OPTICAL FILTERS MATERIAL: FILTER GLASS An improved resistance to larger temperature gradients or rapid temperature changes and an increase in the flexural strength can be achieved through thermal toughening of the filter glass. The improved thermal resistance of toughened filter glass causes a slight deformation and possibly a slight change in the spectral values. Thermal toughening is required for filter glasses placed in front of intense light sources in order to increase their breaking strength. It must be assured that the temperature of the glass does not exceed a temperature of Tg –...

13 OPTICAL FILTERS FILTER GLASS PROPERTIES 5. Filter glass properties In order to develop an assortment of filter glasses, some with extreme filtering properties, in the largest possible spectral area, numerous colorants with different concentrations and many different base glasses had to be developed. In the data section, the following important properties are mostly quantitatively listed for each filter glass type. These are typical values. 5.1 Mechanical density [g/cm3] This is defined as the quotient of mass and volume. Most filter glass types have a density between 2.4 and 2.8 g/cm3....

14 OPTICAL FILTERS FILTER GLASS PROPERTIES 5.4. Chemical Resistance For various chemical demands, especially during different processing steps, we use the resistance classes that apply to optical glass. The greater the resistance of the glass, the smaller the class number. The resistance classes are listed in the data section for all filter glasses. Exact descriptions of the individual test procedures are available upon request. 5.4.1 Stain Resistance, Classification into Stain Resistance Classes FR 0 – 5 The test procedure gives information on possible changes in the glass surface (stain...