1590- Zacharias Janssen devised the first compound microscope. It was composed of a convex objective and a concave eyepiece.

1600- Anton Van Leeuwenhoek invented the simple microscope that consists of a single lens with a relatively high magnification.

1611- Johannes Kepler suggested that construction of a compound microscope that used convex lenses for both the objective and the eyepiece, but he never constructed such an instrument.

1628- Christopher Scheiner constructed Kepler's Microscope.

1684- Christiaan Huygens invented the 2 lens eyepiece.

1813-81 Charles A. Spenser advanced the design of objectives by introducing higher numerical apertures. He also improved color correction.

1840-1905 Ernest Abbe designed the apochromatic objective and the compensating eyepiece.

1853- Francis Wenham invented the darkfield microscope condenser.

1878- R.B. Tolles made the homogeneous immersion objective.

1902- F.E. Ives set forth the basic system for modern binocular eyepieces.

1935- Fritz Zernike successfully applied phase contrasted to the microscope.

1935-Present The basic compound microscope hasn't changed. Of course today, it is manufactured to tighter tolerances, more consistantly, out of different materials with better illumination and various accessories, but although its look may have changed the microscope of today does the same thing the first microscope did in 1590- it enlarges an image.

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Microscope: An instrument for producing enlarged images of objects that are too small to be seen unaided.

A compound microscope is used to view various objects on slides such as bacteria, blood, sections of plants or animals, cells, or even small animals in water. Magnification used for such viewing normally begins at 40X and can exceed 1000X.

A stereo microscope is used to view natural specimens such as insects, plants, and minerals, or electronic components and assemblies, machined or molded parts, virtually any object requiring (3D) viewing. Typical magnification ranges are 10X to 300X. Stereos are referred to as “Zoom” if the instrument allows adjustability or a range of magnification -VS- a “2 step” which is normally magnified at two fixed levels like 20X-40X.

An optical loupe is a binocular set of magnifying lenses mounted on a frame and worn as glasses. Our loupes allow interpupillary adjustment and are normally used when magnification requirements are 2 to 3X. Loupes are used in dental, veterinarian, surgical, and industrial fields and also by hobbyists or by the visually impaired.

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Eyepiece- The magnifying group of lenses nearest to the eye in which the user views the enlarged image formed by the objective lens. Field Of View (F.O.V.)- The diameter of the object that is visible when viewing through the eyepiece after focusing.

Viewing Head- Refers to the part of the microscope that bends the image to ease viewing. The viewing body also allows interpupillary adjustment to accommodate multiple users. Some types of bodies are:

Monocular- single tube (one eye in use)

Teaching- 2 single non-adjusting tubes set at opposing angles to allow two persons to simultaneously view the same object.

Binocular- (sliding) I.P.D. adjustment opens or closes in a straight sliding motion. (Both eyes in use.)

Binocular- (Seidentopf) both eyes in use I.P.D. adjustment opens or closes in a sweeping angular motion like that used in most binoculars.

Trinocular- Both eyes in use like the binocular only there is a third port to enable you to capture the image being viewed by either a photograph or a video image.

Dioptric Adjustment- An adjustment system built into the eyetube or eyepiece allowing the user to change the placement of the lenses to compensate for differences in one's eyes. Often referred to as “Focusing Eyetubes” or eyepieces.

Interpupillary Adjustment (I.P.D.)- The changing of the center distances of the eyepieces through movement in the viewing body to match the centers of the user's eyes allowing you to view one image with both eyes open.

Stage- The platform on which the object to be viewed is placed. “Mechanical” stage refers to the ability to change the position of the object by moving the stage normally through a series of racks and pinions, instead of the object.

Condenser- A contained lens that gathers light rays and focuses them on the object being illuminated. The condensers usually have an adjustable aperture to minimize or maximize the amount of light sent to the object. The aperture is either a series of varying sized holes or a set of iris leaves that change the opening sizes by sliding a lever causing the leaves to overlap.

Koehler Illumination- a system that allows the user to control the amount of light sent from the illuminating system. This diaphragm directly controls the illumination of the field of view resulting in an even distribution of light.

Transmitted Light- Light sent from the base below the specimen being viewed, usually filtered by a frosted glass stage plate or colored filter material.

Incident Light- Light sent from above the specimen being viewed to illuminate the object (usually 3 dimensional) across its peaks and valleys.

Spot Illuminators- A source of lighting separate from the microscope (usually fiber optic) that allows you to concentrate light from above down into deep valleys or holes.

Ring Lights- Fluorescent, Fiberoptic or LED illumination rings that mount on the bottom cover of a stereo microscope to enable lighting from directly above the object, minimizing shadowing typically found with angled incident light.

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