Projector bulbs or projector lamps are light bulbs which are designed to be used in a projector. These bulbs are very bright, and they may only last for a short period of time, due to the high demands placed on projector bulbs while the projector is in operation. Some electronics stores stock these bulbs, and they can also be purchased through specialty suppliers. Keeping a few projector bulbs on hand is a very good idea for people who own a projector, so that bulb failure can be quickly dealt with.
The projector bulb is a critical part of a projector. Depending on the design of the projector, the bulb may cause light to pass directly through a transparent medium like film, creating a projection of the image on the film, or it may be used with a series of mirrors to create a projection. In both cases, the light needs to be extremely strong, because otherwise the projection will be dim and watery, which is not desirable. The light also needs to be consistent, as a flickering bulb can cause problems with the projection.
Most projector bulbs are used with a condenser, a specialized lens which focuses and concentrates the light, ensuring that the distribution is even and strong. After passing through the condenser and the transparent medium, the light hits a focusing lens which can be adjusted. The focus of a projector needs to be changed every time the projector is moved, and special presentations may require additional adjustments to the focus.
Along with getting very bright, projector bulbs also get extremely hot. This can cause a serious problem, as the transparencies used for projection can be meltable or flammable. As a result, a projector bulb is usually surrounded by a heat sink which is designed to pull the heat away, venting it through a fan. While in operation, a projector may become quite hot around the bulb, which is something that operators must watch out for.
Many companies make proprietary bulbs, which makes it important to get a projector bulb which will match with a particular brand. It is also important to follow the wattage recommendations for a specific projector to ensure that it works properly. Using the old bulb as a source for model number or wattage can help with this, although some stores have a catalog of projector bulbs by manufacturer and model which can be used to look up the correct replacement bulb.