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Efficient cooling

- Cooling technology a key to reducing projector size -

First, take a look at the photo.

From left to right: the ELP-3000, the ELP-800 and the EB-1735W

The photo shows three models of projector from the past 15 years, from the oldest to the newest. It gives you a pretty good idea of just how small Epson's projectors have become. Smaller projectors provide numerous environmental benefits. For example, they use less materials and they help reduce environmental impacts during shipping, since a greater number of units can be transported in a each load. Once bulky enough to require two hands to lift, projectors are now compact enough to carry under your arm like a notebook. And the small size has in no way diminished performance: today's Epson projectors render images that are brighter, sharper and more beautiful than ever before. The driving force behind this incredible shrinking act is "wind"; that is, improvements in cooling technology.

Small, lightweight, and brighter than ever

Projectors have become firmly ensconced as essential tools for presentations and meetings. To earn this distinction, they had to evolve over time in response to customer needs for projectors that were smaller, lighter, simpler to set up, easier to use, and both brighter and with better image quality. The most critical of these needs were compactness and lightweight, given the explosion in opportunities users have to transport their projectors between meeting rooms or off-site for presentations and the like. Epson engineers shrunk Epson projectors through a series of design modifications and technical innovations that reduced the size of core components such as the lamp, power supply, and fans. At the same time, they found ways to boost the levels of brightness and resolution so that projected images look bright and crisp even in well-lit rooms.

Environmental impacts are reduced along with the size of the projector body.
Making the body smaller not only improves the ease with which a projector can be used, it also delivers numerous environmental benefits.

  • Resource savings: The amount of materials used can be reduced.
  • Energy savings: Smaller projectors can be transported more efficiently, saving energy during shipping.
  • Waste reduction:

Lamp unit
Lamp unit

Power supply
Power supply

Optical unit
Optical unit

One glance shows the degree to which core components have shrunk.

Beating the heat

Bright projectors need powerful lamps. The problem is that brighter, more powerful lamps produce more heat, heat that has to be dissipated in as efficient a manner as possible. The lamp and optics can reach high temperatures. Engineers have developed a variety of ways to protect projectors and components from the effects of this heat. For example, cooling fans blow air inside the projector to dissipate the heat, and heat-sensitive components are placed as far away from heat-generating components as possible. However, as projector sizes shrink, their surface area decreases, so not only do compact projectors dissipate heat less efficiently, they leave little room to spare between parts. The solution is not simply to add more fans, either, as fans would increase projector size and produce more operating noise. Thus engineering projectors that are simultaneously compact, lightweight and bright has been a serious challenge.

Achieving efficient cooling

Projectors are equipped with multiple cooling fans that send air to heat-generating parts and that exhaust heated air from the case. Early projectors employed a relatively simple architecture in which a large fan was installed in the optical unit near the liquid crystal panels. This early architecture has since evolved through numerous modifications to achieve greater cooling efficiency.

<Airflow ducts>
The light source lamp, the power supply, and the liquid crystal panels through which the lamp light passes all require cooling. Airflow ducts are provided so that air is efficiently delivered to these specific, targeted locations. The ducts enable efficient air circulation, cooling, and exhaustion of heat, making it possible to shrink the space between parts to reduce projector size.

Air drawn in by the fans flows inside the projector along the paths indicated by the arrows to reach the parts that need cooling

<Targeted cooling>
The heart of a projector and what enables it to render great -looking images- is the optical unit, which consists primarily of liquid crystal panels and polarizers arranged in layers. To provide all-over cooling to the optical unit, Epson engineers partitioned the ducts at the outlet to force the air to glide through the narrow gaps between the panels and polarizers.

The flow of air passes through the gaps between the liquid crystal panels and polarizers, providing all-over cooling.

<Selective use of air>
Projectors use two types of fans: axial-flow fans, which can move a large amount of air, and sirocco fans, which can move the air at high velocity. These fans are strategically placed in different locations to efficiently draw air in and exhaust it, providing the air circulation needed to cool the projector.

Lamp unit
Axial-flow fans can move a high volume of air, but the airflow is comparatively gentle. These fans are used mainly for exhaust.

Optical unit
Sirocco fans can force a blast of air at high pressure, so they are used for local cooling of parts.

<Operating when needed>
Fan controllers have also improved. Earlier fans had two speed levels, high and low. The fan would operate at high speed when the temperature rose. Today, the internal temperature of projectors is constantly monitored, and fans are precisely controlled so as to regulate the speed of the airflow according to the amount of heat generated and the projector's operating mode.

Simulated analysis of airflow. Observe the differences in airflow before and after installation of an airflow guide.

The advances in cooling technology that have contributed so much to the downsizing of projectors have also led to longer lamp service lives and the elimination of cool-down periods after use.