Short throw projectors: varieties and rules of operation

The projector is one of the most important devices in the office and educational institution. But even such a particular subtype as short throw projectors has at least two varieties. Their features, as well as the rules of operation, must be taken into account by every buyer.

It is customary to distinguish three fundamental groups of this type of technique according to the length of the focus, that is, according to the interval, separating the projector from the image plane.

• Long focus models turned out to be the simplest, and therefore it was possible to create them first of all.

• Short throw projector mainly used in the office area. With its help, you can easily organize the presentation of a new product, project or organization as a whole. The same technique is used in educational institutions and in other places where it is necessary to illustrate something professionally.

• But if the room is relatively small, it is better suited ultra short throw apparatus. It is also readily used at home.

One way or another, both of these types of projection systems:

• placed close to the screen, which avoids the use of long cables;
• installed quickly and without unnecessary problems;
• make it possible to "simulate a cinema" in a small volume, giving out a widescreen picture;
• do not blind anyone present, even presenters and operators;
• do not cast shadows.

The difference between the short focal length models and the ultra short version is quite noticeable. It consists primarily of the so-called projection ratio.

Projectors can be classified into two main types - laser and interactive. It is worth considering each species in more detail.

These devices aim laser beams at the screen. The signal transmitted in this way is constantly changing. In addition to the laser itself, there is a galvanometric or acousto-optical color scanner inside. The device also includes dichroic mirrors and some other optical parts. If the image is encoded in one color, only one laser is needed; RGB projection requires the use of three optical sources already. Laser projectors can work with confidence on a variety of planes. These are sources of particularly crisp and very intense graphics. Such equipment is even suitable for displaying three-dimensional drawings and various logos.

The DMX protocol is used for control, but in some models the presence of a DAC controller is provided. But it should be borne in mind that the projector can use lasers of various types. For example, systems based on diode lasers with direct pumping have become quite widespread. In addition, diode-pumped and frequency-doubling solid-state systems can be used. But gas lasers have not been used in projector technology for almost 15 years.

This is not just a device capable of displaying this or that picture, but a fundamentally new level of displaying images.It will be possible to interact with them as if with touch surfaces. The main difference is the presence of a special sensor, most often infrared, which is directed towards the screen. The latest models of interactive projectors, unlike past generations, can respond not only to special markers, but also to direct finger actions.

It is useful to consider not firms, in general, but specific product samples. And the first in line is especially bright ultra short throw projector Epson EH-LS100... In the daytime, the device replaces a TV with a screen diagonal of 60 to 70 inches. In the evening hours, you can expand the screen with a diagonal of up to 130 inches. The rational distance to the screen in the first case will be 14 cm, and in the second - 43 cm; for ease of movement, a proprietary sliding stand is used.

Three-matrix technology avoids dimming when displaying intermediate colors. Light efficiency is 50% higher than competitive models. The light source is designed for long-term use. Epson's proprietary concept focuses on the use of external acoustics and smart systems. The product is great for home theater use.

It is worth noting and Panasonic TX-100FP1E. This projector looks stylish outwardly, it differs even among those models that have an official award for the design of the case. The device has an acoustic system with a power of 32 watts. This is a new trend in the development of home theater systems. The refusal to integrate smart systems, as in the case of Epson equipment, is primarily due to the fact that many people prefer external equipment.

Also noteworthy is the projector LG HF85JSequipped with an advanced 4-core processor. The lightweight and compact device is equipped with a built-in smart TV unit. Decent acoustics were used. The designers also took care of the high quality of the Wi-Fi connection. The product weighs 3 kg and can be moved without any problems.

The most important parameter when selecting projectors is the area of ​​their application. Typically, such devices are installed in classrooms, office meeting rooms, and other places where electric lighting is required. Therefore, it is necessary to find out whether they will be able to produce a good picture under such conditions. Mobility is equally important, because work in the office or at school should not be confined to one place. But these criteria are not always significant.

The projectors can also be used as part of a home theater. Such models are designed for operation with the lighting turned off. Their brightness is not too high, but color rendition is improved and a very high contrast is maintained.

Three-matrix projector devices initially separate white light according to the RGB scheme. Single-matrix - can work with only one color at a time. Therefore, color quality and brightness suffer greatly. Obviously, the first type guarantees a more decent picture. The image will look more natural. Attention should also be paid to the contrast level. It should be borne in mind that the specifications do not always provide adequate data. Important: if the projector is bought for brightly lit rooms, this parameter can be neglected. In such a situation, the actual contrast will depend primarily on the overall brightness. But the home theater should be as contrasting as possible.

Sometimes the descriptions of projectors mention that they are equipped with automatic iris. This is indeed a useful device, but its effect only appears when showing a dark scene, where there will be no bright objects.A number of specifications refer to this as "dynamic contrast", which is often confusing.

White balance, otherwise referred to as color temperature, is determined using special techniques that require the use of special techniques. Therefore, this parameter can really be assessed only by reviews. It is almost impossible to establish it directly for an ordinary person. Color gamut is also important. For most of the purposes set by an ordinary consumer, the color gamut should correspond to the sRGB standard.

But with this usually there are no problems. Still, the sRGB standard was developed a long time ago, and most of the projectors are adapted to it. But some expensive developments go further - they can boast of expanded color coverage, with increased saturation. Some experts believe that the updated standard will be worked out when the 4K format is firmly established.

Other recommendations:

• choose a resolution taking into account your needs and the shape of the screen (800x600 is usually enough for showing DVDs and business presentations);
• give preference to products with a sharpening function at the same resolution;
• specify whether the projector will be placed on a table or mounted on a ceiling or wall;
• find out how long the installation and preparation for work will take;
• check for automatic vertical correction;
• find out the availability of additional functions and their real value.

It is generally believed that setting up and adjusting a movie projector is no more difficult than setting up a modern smartphone. But still, problems arise in this area from time to time. Experts strongly recommend using a wired connection whenever possible. This helps to keep the signal more stable and minimizes the risk of malfunctions. Ideally, use a cable that matches the connectors of the two devices without adapters. Older projectors may not have a choice - you have to use the VGA standard. In this case, audio is output through an additional 3.5 mm jack.

Connections to a personal desktop computer are often done using a DVI cable. Occasionally, it is also used to connect a projector to a laptop. But if it is possible to use HDMI even through an adapter, it is better to use it. Both devices are turned off completely before connecting. Locks are tightened if necessary. The projector is turned on before the signal source. Wireless connection is made via Wi-Fi or LAN channels. Inexpensive models use external antennas; modern high-end projectors already have everything you need “on board”.

Sometimes it is necessary to install additional software on computers. Recommendation: if there is no network card, or it is inoperative, a Wi-Fi adapter can help out. It is worth considering that a projector is not a device for showing filmstrips on a sheet. A separate special screen must be used for it. And of course, before you do something, you should look at the instructions.

An indistinct picture or a message about no signal means that you need to check the screen resolution in the settings of your PC or laptop. If the computer “does not see” the connected projector, it must be rebooted after checking the quality of the cable connection. If unsuccessful, you will have to manually adjust the output parameters. It's also worth checking the drivers - they often cause problems with wireless connections.

In the next video, you will find TOP 3 short throw projectors from Aliexpress.