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Bright field microscopy

 
Bright Field Microscopy

 
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Bright field microscopy
 
 
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Bright field microscopy is the simplest of all the optical microscopy illumination
Illumination

Illumination may refer to:*Illumination , the use of light sources*Illumination , the use of light and shadow in art*Illumination , the artistic decoration of hand-written texts...
 techniques. Sample illumination is transmitted (i.e., illuminated from below and observed from above) white light
White

White is a color, the Color vision#Physiology of color perception which is evoked by light that stimulates all three types of color sensitive cone cells in the human eye in near equal amount and with high brightness compared to the surroundings....
. The most common use of the microscope involves the use of an organism mounted to a glass microscope slide
Microscope slide

A microscope slide was originally a 'slider' made of ivory or bone, containing specimens held between disks of transparent mica. These were popular in Victorian era England until the Royal Microscopical Society introduced the standardized microscope slide in the form of a thin sheet of glass used to hold objects for examination under a micro...
.


The magnification of an optical microscope is only limited by the magnifying power of the lens system.






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Corn and Microscope
Bright field microscopy is the simplest of all the optical microscopy illumination
Illumination

Illumination may refer to:*Illumination , the use of light sources*Illumination , the use of light and shadow in art*Illumination , the artistic decoration of hand-written texts...
 techniques. Sample illumination is transmitted (i.e., illuminated from below and observed from above) white light
White

White is a color, the Color vision#Physiology of color perception which is evoked by light that stimulates all three types of color sensitive cone cells in the human eye in near equal amount and with high brightness compared to the surroundings....
. The most common use of the microscope involves the use of an organism mounted to a glass microscope slide
Microscope slide

A microscope slide was originally a 'slider' made of ivory or bone, containing specimens held between disks of transparent mica. These were popular in Victorian era England until the Royal Microscopical Society introduced the standardized microscope slide in the form of a thin sheet of glass used to hold objects for examination under a micro...
.

Common components

  • Base - Supporting structure that usually contains an electrical light source or illuminator.
  • Objective lens(es)- Magnify the image.
  • Oculars - Magnify the image from the objective lens. A microscope with one ocular lens is often called a monocular, a microscope with two oculars is called a binocular.
  • Arm - The support structure that connects the lens systems to the base.
  • Body tube - Sends light to the ocular lens.
  • Condenser lens - Directs light to pass through the specimen.
  • Stage - Platform that allows mechanical movement of a microscope slide.
  • Adjustment knobs - Course and fine focus
    Focus (optics)

    In geometrical optics, a focus, also called an image point, is the point where light rays originating from a point on the object converge ....
     adjustment.


The magnification of an optical microscope is only limited by the magnifying power of the lens system. However, the limit of magnification
Magnification

Magnification is the process of enlarging something only in appearance, not in physical size. This enlargement is quantified by a calculated number also called magnification....
 for most light microscopes is 1000x which is set by an intrinsic property of lenses called resolving power
Resolving power

Resolving power may refer to:* Angular resolution* Spectral resolution* Resolution ...
.

Advantages

  • Simplicity of setup with only basic equipment required.
  • No sample preparation required, allowing viewing of live cells.


Limitations

  • Very low contrast
    Contrast

    Contrast is the dissimilarity or difference between things:* Contrast , expressing distinctions between words* Contrast , the difference in color and light between parts of an image....
     of most biological samples.
  • Low apparent optical resolution
    Optical resolution

    Optical resolution describes the ability of an imaging system to resolve detail in the object that is being imaged.An imaging system may have many individual components including a lens and recording and display components....
     due to the blur of out of focus material.


Enhancements

  • Reducing or increasing the amount of the light source via the iris diaphragm.
  • Use of an oil immersion objective lens and a special immersion oil placed on a glass cover over the specimen. Immersion oil has the same refraction
    Refraction

    Refraction is the change in direction of a wave due to a change in its speed. This is most commonly observed when a wave passes from one optical medium to another....
     as glass and improves the resolution of the observed specimen.
  • Use of sample staining methods for use in microbiology
    Microbiology

    Microbiology is the study of microorganisms, which are unicellular or cell-cluster microscopic organisms. This includes eukaryote such as fungi and protists, and prokaryotes, which are bacteria and archaea....
    , such as simple stains (Methylene blue
    Methylene blue

    Methylene blue is a Heterocyclic ring aromaticity chemical compound with molecular formula: carbon16hydrogen18chlorinenitrogen3sulfur....
    , Safranin
    Safranin

    Safranin is a staining used in histology and cytology. Safranin is used as a counterstain in some staining protocols, colouring all cell nucleus red....
    , Crystal violet) and differential stains (Negative stains, flagellar stains, endospore stains).
  • Use of a colored (usually blue) or polarizing filter
    Filter (optics)

    Optical filters, generally, belong to one of two categories. The simplest, physically, is the absorptive filter, while the latter category, that of interference or dichroic filters, can be quite complex....
     on the light source to highlight features not visible under white light. The use of filters is especially useful with mineral
    Mineral

    A mineral is a naturally occurring solid formed through Geology processes that has a characteristic chemical composition, a highly ordered atomic structure, and specific physical properties....
     samples.