What are microscopesand how do they work

Choosing the right microscope objective is critical in order to obtain an accurate image of a specimen (i.e. an image that provides magnification of the object but does not distort it.)

Microscope parts and functions

[Prev Section] [Next Section] [Table of Contents] [Chapter Contents] A microscope is used for viewing small things; the first microscope was a single lens used as a simple magnifier. Today we usually mean a two-lens or compound microscope when we say "microscope". Of course each "lens" in our simple sketch in Figure 19.16 may actually be made of several elements to reduce aberrations. The first lens, the one near the object, is known as the objective lens and the second lens, the one near the viewer's eye, is known as the eyepiece lens (or the ocular lens). For a typical microscope, these will both be lenses of short focal length, just a couple of centimeters or so. Figure 19.16 A compound microscope. The final image is a virtual image and may be located at infinity. As shown in Figure 19.16 an object is placed just beyond the focal length of the objective lens. With the object's being beyond the focal length, a real image is formed as shown; a card could be held inside the microscope tube and this image would be projected upon it. The objective lens forms a real image that is larger than the object. The positions of the lenses are adjusted so this image formed by the objective lens falls just inside the focal length of the eyepiece. The eyepiece is then used as a simple magnifier to view this image; this image acts as the object for the eyepiece. Since this object for the eyepiece lies inside the focal length, an enlarged, virtual image will be produced. The eyepiece may be focused so this virtual image is at infinity-or wherever is comfortable for the viewer. [Prev Section] [Next Section] [Table of Contents] [Chapter Contents]

There are two types of microscopes: optical microscopes and electron microscopes. In this guide, once the differences between these two types of microscopes have been presented, only optical microscopes will be discussed.

A microscope is used for viewing small things; the first microscope was a single lens used as a simple magnifier. Today we usually mean a two-lens or compound microscope when we say "microscope". Of course each "lens" in our simple sketch in Figure 19.16 may actually be made of several elements to reduce aberrations. The first lens, the one near the object, is known as the objective lens and the second lens, the one near the viewer's eye, is known as the eyepiece lens (or the ocular lens). For a typical microscope, these will both be lenses of short focal length, just a couple of centimeters or so. Figure 19.16 A compound microscope. The final image is a virtual image and may be located at infinity. As shown in Figure 19.16 an object is placed just beyond the focal length of the objective lens. With the object's being beyond the focal length, a real image is formed as shown; a card could be held inside the microscope tube and this image would be projected upon it. The objective lens forms a real image that is larger than the object. The positions of the lenses are adjusted so this image formed by the objective lens falls just inside the focal length of the eyepiece. The eyepiece is then used as a simple magnifier to view this image; this image acts as the object for the eyepiece. Since this object for the eyepiece lies inside the focal length, an enlarged, virtual image will be produced. The eyepiece may be focused so this virtual image is at infinity-or wherever is comfortable for the viewer. [Prev Section] [Next Section] [Table of Contents] [Chapter Contents]

Whatis microscope in science

The main difference between these two types of microscopes lies in the way the sample to be observed is prepared and passed through. This is what determines the quality of the image (magnification, color, black and white).

Figure 19.16 A compound microscope. The final image is a virtual image and may be located at infinity. As shown in Figure 19.16 an object is placed just beyond the focal length of the objective lens. With the object's being beyond the focal length, a real image is formed as shown; a card could be held inside the microscope tube and this image would be projected upon it. The objective lens forms a real image that is larger than the object. The positions of the lenses are adjusted so this image formed by the objective lens falls just inside the focal length of the eyepiece. The eyepiece is then used as a simple magnifier to view this image; this image acts as the object for the eyepiece. Since this object for the eyepiece lies inside the focal length, an enlarged, virtual image will be produced. The eyepiece may be focused so this virtual image is at infinity-or wherever is comfortable for the viewer.

Types of microscope

The objective must also render an accurate image of the observed sample and correct defects in optical systems, also known as optical aberrations.

There are several types of optical microscopes to choose from, depending on the sample you want to observe. First you have to choose between upright and inverted microscopes.

The head of a microscope is the top part that the eyepieces are attached to. Different types of heads exist: straight heads and inclined heads.

Figure 19.16 A compound microscope. The final image is a virtual image and may be located at infinity. As shown in Figure 19.16 an object is placed just beyond the focal length of the objective lens. With the object's being beyond the focal length, a real image is formed as shown; a card could be held inside the microscope tube and this image would be projected upon it. The objective lens forms a real image that is larger than the object. The positions of the lenses are adjusted so this image formed by the objective lens falls just inside the focal length of the eyepiece. The eyepiece is then used as a simple magnifier to view this image; this image acts as the object for the eyepiece. Since this object for the eyepiece lies inside the focal length, an enlarged, virtual image will be produced. The eyepiece may be focused so this virtual image is at infinity-or wherever is comfortable for the viewer.

What are microscopesmade of

As shown in Figure 19.16 an object is placed just beyond the focal length of the objective lens. With the object's being beyond the focal length, a real image is formed as shown; a card could be held inside the microscope tube and this image would be projected upon it. The objective lens forms a real image that is larger than the object. The positions of the lenses are adjusted so this image formed by the objective lens falls just inside the focal length of the eyepiece. The eyepiece is then used as a simple magnifier to view this image; this image acts as the object for the eyepiece. Since this object for the eyepiece lies inside the focal length, an enlarged, virtual image will be produced. The eyepiece may be focused so this virtual image is at infinity-or wherever is comfortable for the viewer.

Microscopes are used for many applications in science and industry. They are used in particular for quality control (semiconductor processing, metallurgical analysis) but also in the laboratory (medical imaging, cell research).

What are microscopesused for

A microscope is used for viewing small things; the first microscope was a single lens used as a simple magnifier. Today we usually mean a two-lens or compound microscope when we say "microscope". Of course each "lens" in our simple sketch in Figure 19.16 may actually be made of several elements to reduce aberrations. The first lens, the one near the object, is known as the objective lens and the second lens, the one near the viewer's eye, is known as the eyepiece lens (or the ocular lens). For a typical microscope, these will both be lenses of short focal length, just a couple of centimeters or so. Figure 19.16 A compound microscope. The final image is a virtual image and may be located at infinity. As shown in Figure 19.16 an object is placed just beyond the focal length of the objective lens. With the object's being beyond the focal length, a real image is formed as shown; a card could be held inside the microscope tube and this image would be projected upon it. The objective lens forms a real image that is larger than the object. The positions of the lenses are adjusted so this image formed by the objective lens falls just inside the focal length of the eyepiece. The eyepiece is then used as a simple magnifier to view this image; this image acts as the object for the eyepiece. Since this object for the eyepiece lies inside the focal length, an enlarged, virtual image will be produced. The eyepiece may be focused so this virtual image is at infinity-or wherever is comfortable for the viewer. [Prev Section] [Next Section] [Table of Contents] [Chapter Contents]

19.5 Microscope [Prev Section] [Next Section] [Table of Contents] [Chapter Contents] A microscope is used for viewing small things; the first microscope was a single lens used as a simple magnifier. Today we usually mean a two-lens or compound microscope when we say "microscope". Of course each "lens" in our simple sketch in Figure 19.16 may actually be made of several elements to reduce aberrations. The first lens, the one near the object, is known as the objective lens and the second lens, the one near the viewer's eye, is known as the eyepiece lens (or the ocular lens). For a typical microscope, these will both be lenses of short focal length, just a couple of centimeters or so. Figure 19.16 A compound microscope. The final image is a virtual image and may be located at infinity. As shown in Figure 19.16 an object is placed just beyond the focal length of the objective lens. With the object's being beyond the focal length, a real image is formed as shown; a card could be held inside the microscope tube and this image would be projected upon it. The objective lens forms a real image that is larger than the object. The positions of the lenses are adjusted so this image formed by the objective lens falls just inside the focal length of the eyepiece. The eyepiece is then used as a simple magnifier to view this image; this image acts as the object for the eyepiece. Since this object for the eyepiece lies inside the focal length, an enlarged, virtual image will be produced. The eyepiece may be focused so this virtual image is at infinity-or wherever is comfortable for the viewer. [Prev Section] [Next Section] [Table of Contents] [Chapter Contents]