EYMA TEKMEN LIQUID CRYSTALS OPTICAL FILTERS ITUBiomedical Engineering

ŞEYMA TEKMEN LIQUID CRYSTALS & OPTICAL FILTERS ITU-Biomedical Engineering BYM 501 E Fundamentals of Biomedical Engineering

1 -) LIQUID CRYSTALS • INTRODUCTION • CLASSIFICATION OF LIQUID CRYSTALS • APPLICATIONS 2 -) OPTICAL FILTERS • INTRODUCTION • CATEGORIES OF OPTICAL FILTERS • APPLICATIONS

LIQUID CRYSTALS INTRODUCTION ▪ A phase occurs that between solid & liquid ▪ There are many different types of liquid-crystal phases… ▪ possess properties not found in either liquids or solids ▪ some changes colour with temperature

LIQUID CRYSTALS CLASSIFICATION OF LIQUID CRYSTALS I. THERMOTROPIC PHASE : LC phase transitions resulted from temperature changes a) Nematic Phase : in the same direction , flexible b) Smectic Phase : in layers , laminar c) Cholesteric Phase: chiral nematic phase d) Discotic Phase : disk-shaped , in a layer

LIQUID CRYSTALS II. LYOTROPIC PHASE LC phase is formed when a molecule is dissolved in a suitable solvent III. METALLOTROPIC PHASE organic & inorganic molecules

LIQUID CRYSTALS APPLICATIONS ▪ Surface Thermometry ▪ Battery Testing Strips ▪ Biological Liquid Crystals ▪ Liquid Crystal Display ( LCD)

OPTICAL FILTERS § Optical filter are transmit light different wavelength and eliminate unwanted light. § Optical Filters are ideal for life science, imaging, industrial, or defence industries. § Used in photography , optical instruments, color stage lighting and fluorescence microscopy…

OPTICAL FILTERS CATEGORIES OF OPTICAL FILTERS § Absorptive filters: - Colour , glass filters…absorb the unwanted light. - As the absorbed light is converted into heat. . § Interference filters: - Dichroic, Dielectric, reflective filters… reflect the unwanted wavelengths

OPTICAL FILTERS Types of Filters; Long pass and Short pass filters: characterized by their T max and cut on, cut off wavelength. Bandpass Filters

OPTICAL FILTERS APPLICATIONS OF THE OPTICAL FILTERS No Filter Polarization Filters IR Band pass Filter Infrared Filter; Metrology, thermograph, heating Diagram illustrating the optical filters and light path of a fluorescence microscope. Neutral Density Filters

REFERENCES ▪ Liquid Crystals – Iam-Choon Khoo ( pg: 1 -7) ▪ Liquid Crystals - The 'Fourth' Phase of Matter (Review) Rekha Devi ▪ Liquid crystal – Wikipedia ▪ Stephen Lower, Professor Emeritus (Simon Fraser U. ) Chem 1 Virtual Textbook ▪ Different types of Optical Filters and their Realistic Application - Vijay Laxmi Kalyani, Varsha Sharma ▪ University of Edinburgh -Spectral Filtering ▪ www. thomasnet. com/articles/automation-electronics/filteroptical ▪ Herbert Venghaus, Norbert Grote, “Fiber optics communication key device