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3 main parts of compound light microscope

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From Wikipedia

Microscope

. A microscope (from the μικ�ός, mikrós, "small" and σκοπεῖν, skopeîn, "to look" or "see") is an instrument to see objects too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy. Microscopic means invisible to

Optical microscope

The optical microscope, often referred to as the "light microscope", is a type of microscope which uses visible light and a system of lenses to magnify images of small samples. Optical microscopes are the oldest design of microscope and were designed around 1600. Basic optical microscopes can be very simple, although there are many complex designs which aim to improve resolution and sample contrast. Historically optical microscopes were easy to develop and are popular because they use visible light so the sample can be directly observed by eye.

The image from an optical microscope can be captured by normal light-sensitive cameras to generate a micrograph. Originally images were captured by photographic film but modern developments in CMOS and charge-coupled device (CCD) cameras allow the capture of digital images. Purely Digital microscopes are now available which just use a CCD camera to examine a sample, and the image is shown directly on a computer screen without the need for eye-pieces.

Alternatives to optical microscopy which do not use visible light include scanning electron microscopy and transmission electron microscopy.

Optical configurations

There are two basic configurations of the conventional optical microscope, the simple (one lens) and compound (many lenses). The vast majority of modern research microscopes are compound microscopes while some cheaper commercial digital microscopes are simple single lens microscopes. A magnifying glass is, in essence, a basic single lens microscope. In general microscope optics are static; to focus at different focal depths the lens to sample distance is adjusted and to get a wider or narrower field of view a different magnification objective lens must be used. Most modern research microscopes also have a separate set of optics for illuminating the sample.

Single lens (simple) microscope

A simple microscope is a microscope that uses only one lens for magnification, and is the original design of light microscope. Van Leeuwenhoek's microscopes consisted of a small, single converging lens mounted on a brass plate, with a screw mechanism to hold the sample or specimen to be examined. [http://www.brianjford.com/wavrbcs.htm Demonstrations] by British microscopist have images from such basic instruments. Though now considered primitive, the use of a single, convex lens for viewing is still found in simple magnification devices, such as the magnifying glass, and the loupe.

Compound microscope

A compound microscope is a microscope which uses multiple lenses to collect light from the sample and then a separate set of lenses to focus the light into the eye or camera. Compound microscopes are heavier, larger and more expensive than simple microscopes due to the increased number of lenses used in construction. The main advantages of multiple lenses are improved numerical aperture (see resolution limit below), reduced chromatic aberration and exchangeable objective lenses to adjust the magnification. A compound microscope also makes more advanced illumination setups, such as phase contrast.

History

Invention

It is difficult to say who invented the compound microscope. Dutch spectacle-makers Hans Janssen and his son Zacharias Janssen are often said to have invented the first compound microscope in 1590, but this was a declaration made by Zacharias Janssen himself during the mid 17th century. The date is unlikely, as it has been shown that Zacharias Janssen actually was born around 1590. Another favorite for the title of 'inventor of the microscope' was Galileo Galilei. He developed an occhiolino or compound microscope with a convex and a concave lens in 1609. Galileo's microscope was celebrated in the Accademia dei Lincei in 1624 and was the first such device to be given the name "microscope" a year later by fellow Lincean Giovanni Faber. Faber coined the name from the Greek words μικ�όν (micron) meaning "small", and σκοπεῖν (skopein) meaning "to look at", a name meant to be analogous with "telescope", another word coined by the Linceans.

Christiaan Huygens, another Dutchman, developed a simple 2-lens ocular system in the late 17th century that was achromatically corrected, and therefore a huge step forward in microscope development. The Huygens ocular is still being produced to this day, but suffers from a small field size, and other minor problems.

Popularisation

Anton van Leeuwenhoek (1632–1723) is credited with bringing the microscope to the attention of biologists, even though simple magnifying lenses were already being produced in the 16th century. Van Leeuwenhoek's home-made microscopes were very small simple instruments, with a single, yet strong lens. They were awkward in use, but enabled van Leeuwenhoek to see detailed images. It took about 150 years of optical development before the compound microscope was able to provide the same quality image as van Leeuwenhoek's simple microscopes, due to difficulties in configuring multiple lenses. Still, despite widespread claims, van Leeuwenhoek is not the inventor of the microscope.

Lighting techniques

While basic microscope technology and optics have been available for over 400 years it is much more recently that techniques in sample illumination were developed to generate the high quality images seen today.

In August 1893 August Köhler developed From Yahoo Answers

Question:

Answers:I. Illuminating part(s) condenser illuminator diaphragm II. Magnifying part(s) Objectives: LPO - 10x HPO - 40x / 60X OIO - oil immersion objctive - 100x III. Mechanical part(s) arm base body tube stage rack stop focusing knobs (fine adjusmnt and coarse adjustment) dust shield revolving nosepiece inclination joint... Hope that helps,,,,,,,

Question:What is the functions of the following parts of compound light microscope" a. condenser lens b. iris diaphragm c.objective d.ocular 2. In order, list the lenses in the light path between a speciman viewed with the compund light microscope and its imahe on the retina of the eye. 3.What happens tp the contrast and the resolving power when the aperture of the condenser (that is, the size of tge hole through which light passes before it reaches rhe speciman) of a compund light miscroscope is decreased? 4.What happens to the field of view in a compound light microscope when the total magnification is increased? 5. Describe the importance of the following concepts to microscopy. a. magnification b. resolving power c. contrast

Answers:a. Condenser focuses the light from the source (lamp) onto the slide. b. Iris diaphragm regulates the amount of light 2. The light path: lamp - condenser lens - specimen - objective lens - eyepience (also a lens) - final image as seen by the eye. (FIGURE OUT THE ANSWER URSELF NOW!)

Question:What is a compound microscope? It's parts and functions? And what are the 3 main parts? Thank you very much...

Answers:Compound optical microscope The compound microscope uses a set of many lenses in order to maximize magnification. The diagram below shows a compound microscope. In its simplest form - as used by Robert Hooke, for example - the compound microscope would have a single glass lens of short focal length for the objective, and another single glass lens for the eyepiece or ocular lens. Modern microscopes of this kind are usually more complex, with multiple lens components in both objective and eyepiece assemblies. These multi-component lenses are designed to reduce aberrations, particularly chromatic aberration and spherical aberration. In modern microscopes the mirror is replaced by a lamp unit providing stable, controllable illumination. The Compound Light Microscope Eyepiece Objectives Fine Adjustment Knob Power Switch Stage Diaphragm Base Body Tube Nosepiece Stage Clips Stage Stop Coarse Adjustment Knob Aperture Arm Light Source...

Question:I believe it has something to do with TEM & SEM, but I'm not sure.

Answers:Compound microscopes are a type of microscope that uses lenses and light. Theses are the ones you have probably seen before. http://en.wikipedia.org/wiki/Microscope#Optical_microscopes TEM (transmission electron microscope) and SEM (scanning electron microscope) are both types of electron microscopes. These are extremely expensive, so unless you happen to be at a university doing research, you will not see one. They take up entire rooms. TEM images are 2D black and white images able to see the internal contents of cells. For more info (and example photos): http://en.wikipedia.org/wiki/Transmission_electron_microscopy SEM images result is 3D black and white photos of the surfaces of whatever is being viewed. For more on SEM: http://en.wikipedia.org/wiki/Scanning_electron_microscope

From Youtube

Compound Light Microscope :A short introduction to the compound light microscope.

Introducing the Microscope - Part 3 :Visit the Microscopy Blog for more videos: www.microbehunter.com Introducing the Compound Microscope - Part 3 Instructional video which explains the different parts of a light microscope.