Kelowna Movie Projector

APERTURE
The area of the stage that is available for projecting an image. Usually comes in the following sizes: 10“ X 10”, 10.5” X 10.5” and 11.25” X 11.25” (A4).

ARTICULATED HEAD
A closed projector head where the mirror will move one-half the distance when the image is tilted up on the screen.

COATED STAGE
Hard coating on a reflective optical stage (fresnel lens) that resists scratching, so that the projected visuals stay sharp and clear.

COLOR TUNING
Adjusts the edge-to-edge uniformity of the projected light to eliminate yellow or blue corners. This gives an optimized image, no matter what the projector to screen distance, within the prescribed area.

CONVECTED COOLED
Natural cooling of the projector lamp by the upward flow of heated air, without the use of a fan. Usually used in reflective type projectors that have the lamp in the head assembly.

DOUBLET HEAD
A projector head that has a two element lens. ELEVATION ANGLE
The elevation that the projected image can be tilted up to, and still project a full image onto the screen.

FOCAL LENGTH
The value given to a lens, stated in inches or millimeters. The smaller the focal length, the wider the angle of the image. Focal length is the distance between the lens and its focal point.

FOCUS CORRECTION
A feature that is used when it is necessary to project an image onto a vertical surface (such as a wall) with a high tilt angle of the head, making it possible to obtain uniform focus from top to bottom of the image. The feature does not eliminate keystoning.

FRESNEL LENS
A flat lens that is composed of a series of closely spaced grooves that control the refraction of light. It is usually part of the stage.

ILLUMINATION
The density of light projected onto a screen or other surface. Stated in lumens.

KEYSTONING
Keystoning is caused when the projected image is not perpendicular to the screen. Correct keystoning by tilting the screen until it is perpendicular to the light beam axis.

LET RUN THERMOSTAT
See Post Cool Thermostat.

LIQUID CRYSTAL DISPLAY (LCD)
A display panel that sits on top of the projector stage which creates an image that is generated by a computer.

LUMEN
The unit of illumination on a screen or other surface. One lumen is the light of one candle power on each square foot of a surface of a sphere at a radius of one foot from the light source.

OPEN HEAD
A projection head where the mirror and the lens is not enclosed. The image is raised on the screen by tilting the mirror up.

OPTICAL TUNING
See Color Tuning.

OVERHEAT THERMOSTAT
Turns the lamp off if the projector reaches an unsafe temperature.

POST COOL THERMOSTAT
A thermostat that allows the projector fan to continue to run after the lamp has been turned off, which reduces the temperature of the unit.

REFLECTIVE TYPE PROJECTOR
An overhead projector where the light source is located in the head assembly and shines down onto the stage. The light is then reflected from the fresnel lens, back through the head and onto the screen. Usually used in light weight, portable projectors.

SINGLET HEAD
A projector head with a lens that has only one element. STAGE
The flat area of the projector where the transparency film is placed.

SAFETY THERMOSTAT
See overheat thermostat.

TRANSMISSIVE TYPE PROJECTOR
An overhead projector where the light source is under the stage and light is transmitted through the transparency film to the head and onto the screen.

TRIPLET LENS
A projection lens that has three elements contained in a single assembly.

VARIFOCAL LENS
A projection lens containing movable elements to permit focusing of the image. (Not a zoom)

WIDE ANGLE LENS
A lens that will project a larger image on a screen at a closer distance than a standard lens will project. Usually has a focal length of 11.5” (293mm) or smaller.