Projector’s Parts & Its Functions
The video projector, or just projector for short, is a piece of equipment that video-streams images from its source to a screen. It works in the same way as an overhead projector. A typical modern video projector consists of four main components: the projection lens system, the lamphouse and bulb, the color wheel or technologies such as LCD panels that produce red/green/blue light when stimulated by high-intensity light sources (such as blue LEDs), and the cooling system.
1. Projection Lens System
The first component is the projection lens system. This structure consists of a series of lens elements connected in the proper sequence to form an optical system, focusing light from the lamp into a small image on the screen (the “lens”). The lens system may be located inside or outside the lamphouse. It is usually mounted onto an adjustable base or lens-shimming mechanism for adjusting focus and tracking magnification and keystone correction.
2. Lamphouse And Bulb
The second component is the lamphouse, which houses the lamp. Electrical controls adjust the lamp’s output to ensure a specified level of brightness and color fidelity. The bulb is the light source that emits high-intensity light (usually blue light) from one or two lamps, or, in modern systems, multi-element lamps also generate yellow and red lights.
3. Color Wheel & Other Technologies
The third component is the color wheel. This is a disc with red, blue, and green segments that rotate in front of the light beam (a process called “interference”), producing different light colors. The rotation speed can be adjusted so the projector can simulate changing conditions of daylight, including outdoor and indoor settings. The LCD panels use a series of liquid crystal cells to accomplish similar results.
4. Cooling System
The final component is the cooling system. This unit contains a compressor, condenser fan(s), and refrigeration unit (either a coil or evaporator) that cools down the liquid crystal panel, lamphouse, and bulb to maintain their desired operating temperatures.
Other Parts Of A Projector
1. Focus and Keystone
The video projector can also be equipped with a focusing mechanism and keystone correction. The focus mechanism adjusts the lens to produce a sharp image, whereas the keystone correction corrects for anamorphic distortion at the screen corners. This is achieved by physically moving parts of the optical system (most commonly a set of prisms) during operation.
Tracking is another vital part of a projector that works according to a procedure to compensate for slight movement caused by the image on an uneven screen. This is achieved by the addition of parts (usually gears or rollers) inside the optical system.
3. Offset/Perspective Correction
The video projector also entails an offset/perspective correction mechanism to compensate for vertical and horizontal displacement caused by vertical and horizontal pupils of the human eye. This is achieved by mechanically moving parts during operation.
4. Lens Aperture Size And F-Stop
The aperture size and f-stop are also a vital part of a projector that measures the diameter of the lens opening and its focal distance, respectively.
5. Lens Shift
A lens shift mechanism, also known as lens offset, relates to the vertical and horizontal movement of the image source to compensate for geometric distortion of the lens due to variations in mounting height.
From Where Can The Parts Be Purchased?
The parts of a projector are not very expensive; they can be bought and sold at affordable prices:
1. Focus Mechanism: It costs around $35-$70
2. Projection Lens System: It costs around $100-$115
3. Cooling System: It costs around $120-$150 for a coil cooling unit and about $230-$260 for an evaporator cooling unit. Both are manufactured by Panasonic.
4. Tracking System: It costs around $100-$130.
5. Offset/Perspective Correction: It costs around $200-$250 for a mechanical system and about $800-$1000 for an electronic system.
6. Lens Aperture Size And F-Stop: It costs around $150-$200 for a lens aperture size and the f-stop is usually sold separately at around $50-$100.
These parts can be purchased from local stores or online from sites like Amazon.
How Does A Projector Work?
A projector works by reflecting the light from a lamp in a series of mirrors and lenses that are arranged so that they can converge light from the source onto the screen. It works in the same way as an overhead projector.
The light from the lamp is reflected off a set of parabolic mirrors in horizontal and vertical directions. Then it is reflected in the relay lens that is placed behind the lamp. The light then passes through another set of mirrors, only to pass through the relay lens again. It then travels through a series of focusing lenses and bounces on a mirror to a reflector that reflects the image onto a condenser lens, which projects it onto the screen.
As you can see, there are many aspects of the projector and everyone will have their own opinion on how a projector should be. A projector is an animation-oriented machine and a costly buy for an individual. However, it comes with numerous advantages and can be used as a handy accessory for different projects and presentations. Many common features are present in almost all present-day projectors: an image processing system, a cooling system, and a lamphouse with lamps and it will remain a worthy purchase.
Q. Why are some projectors slow to respond?
A. Speed varies with the specifications of the equipment used. Although some projectors are very slow under certain circumstances, it has nothing to do with the quality of the projection system but more with the speed at which light can travel through it. The processing system on a projector is built to move a large amount of data at high speeds. Manufacturers will often use the same components in a processor or use standard off-the-shelf PC motherboards as those in their processors.
Q. Why is there humming noise coming from the screen or no picture at all when I turn it on, even though the lamp is on?
A. The most common issues are:
1. The projector is in standby mode. Press any key or remote control button on your remote control to take the projector out of standby mode.
2. The lamp is on but not receiving power. Check if the lamp door is closed properly and power is being delivered to the machine. Check the power consumption through a voltmeter or plugging it into a surge protector.
3. The lamp has burnt out. A lamp that does not emit light is often a sign of a bulb that has completed its useful life. Check for burned-out bulbs at merchants that sell projection equipment and keep a spare one in case you need to replace it directly from the projector if needed.