Types and Grades of Optical Glass
Types and Grades of Optical Glass
Optical glass comes in many varieties, classified based on their optical properties, composition, and application. Here are some common types of optical glass and their corresponding grades:
1. Standard Optical Glass
Standard optical glass is mainly used for lenses, optical elements, and other common optical components. It has good transparency, refractive index, and low dispersion properties.
BK7: One of the most common optical glasses, with a refractive index of about 1.516 and low dispersion. It is widely used for lenses and other optical components.
B270: A high-quality optical glass with low dispersion and high light transmission, commonly used for high-precision optical elements.
K9: Similar to BK7, often used for lenses, windows, and other optical elements with good overall performance.
2. High Refractive Index Optical Glass
This type of glass has a higher refractive index and is suitable for applications requiring higher optical performance, such as high-definition lenses and microscope objectives.
SF2: A high refractive index glass with a refractive index of about 1.83, commonly used for making high-precision optical lenses.
SF10: An optical glass with a relatively high refractive index, suitable for making lenses that require large optical aberration corrections.
3. Low Dispersion Optical Glass
Low dispersion optical glasses have minimal refractive index changes and reduce chromatic aberration in optical systems.
FPL51: This glass has extremely low dispersion, often used for making achromatic lenses to correct chromatic aberration.
LaK9: A sodium-potassium glass doped with cerium, featuring low dispersion, commonly used for chromatic aberration correction in optical designs.
4. Optical Plastics
In addition to traditional optical glass, optical plastics are also an important choice for manufacturing optical components, often used in lightweight and cost-effective optical systems.
CR-39: A commonly used optical plastic widely applied in eyeglass lenses and other low-cost optical elements.
Polycarbonate: A plastic material with high impact resistance but slightly lower refractive index, suitable for specific optical applications.
5. Laser Window Glass
This type of glass is primarily used for laser system windows and can withstand high-power laser irradiation. Common materials include:
ZnSe: Used for laser windows in the mid-infrared wavelength range, especially for CO2 lasers.
Zinc Sulfide (ZnS): Widely used for infrared lenses and windows, especially for long-wave infrared laser applications.
6. Special Optical Glass
This category includes glass designed for specific optical applications, such as infrared, ultraviolet, or laser applications.
Borosilicate Glass (e.g., Pyrex): Known for its high thermal resistance and chemical stability, suitable for optical components requiring high thermal stability.
Barium Aluminosilicate Glass: Offers good optical properties and is commonly used for ultraviolet or other specialized wavelength applications.
7. Infrared Optical Glass
This type of glass is specifically designed for infrared wavelengths and provides excellent transmission in the infrared spectrum.
Germanium (Ge): Commonly used for infrared lenses, especially in the 8-12 microns infrared range.
Sapphire: With extremely high hardness and transparency, sapphire is widely used for infrared windows, laser protection windows, and more.
Common Optical Glass Grades:
Schott Optical Glass Grades: Such as BK7, SF2, SF10, F1, FPL51, etc.
Hoya Optical Glass Grades: Such as H-K9L, H-BK7, H-FPL51, etc.
Ohara Optical Glass Grades: Such as O-UV, O-FPL51, etc.
Key Factors When Choosing Optical Glass:
Refractive Index (n): Affects the speed at which light travels through the glass, influencing optical design.
Dispersion (nd): Determines the amount of chromatic dispersion that occurs when light passes through the optical element.
Light Transmission: Affects the transparency of the glass, with typical optical glasses having light transmission rates above 90% in the visible range.
Mechanical Strength: The hardness and impact resistance of the glass, important for certain applications.
Thermal Resistance: Optical glasses used in high-temperature environments need high thermal stability.
These optical glasses are widely used in telescopes, microscopes, cameras, laser equipment, fiber optic communication, optical sensors, and more.
