Save our eyes: LED projectors

For years that computer technology is changing our world for the better. But, together with incredible opportunities, it carries a great threat: a heavy load on our eyes.

Much has been written about the causes of vision deterioration as a result of prolonged work behind the screens of computers / tablets. Most boiled down to the idea that human eyes are not designed for the load that they receive when working behind LCD screens. Programmers and representatives of other computer-related professions feel this negative impact on themselves especially strongly.

How to be in this situation? Hasn't humankind invented a way to avoid negative effects on the eyes while working on computers?
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In this article I want to tell about LED-projectors, which, it seems to me, have less negative impact on the eyes and may well become a replacement for LCD screens.

Foreword

But, for starters, I propose to consider other alternative display technologies.

E-ink, you are the world!

To save mankind, e-ink technology (the so-called “electronic ink”) was threatened. The essence of the technology is as follows: e-ink “draws” a static picture that a person sees in the light reflected from the screen. The source of light can (and should) be external, e-ink itself is not. This method is actually a natural way of obtaining information for the human eye.

Like many relatively young technologies, e-ink has its drawbacks.

First, the update time on the screen is significantly inferior to conventional LCD monitors (about 50 times). Secondly, almost all variations of the technology do not have the ability to present information in color, and the one that is - is undeveloped.

It is because of these shortcomings that this technology has remained niche mainly for the production of electronic books. Let's hope that the technology will someday be improved, and it can be used for the production of monitors and not only. In the meantime, it is necessary to recognize - as a complete replacement of conventional LCD screens, the technology is not suitable.

In other matters, it is possible to use some models of electronic books (with an e-ink screen) as a second computer monitor. And on some - to stake out almost full-featured Android. If the topic is interesting - I can tell you about it in a separate article.

More details about e-ink in an article on wikipedia .

Warm lamp projectors

Generally, projectors are an ancient technology. Its essence is simple: the projector shines on the projection plane, the light from it bounces off and the person sees the picture. The further the projector is, the larger the image diagonal will be, and the lower the light output from the projection plane will be. On the contrary, the closer - the smaller the diagonal and more light output.

It seems to me that this method of obtaining information for the human eyes is more natural than from LCD screens. The light is more diffuse, less bright, you can make a large diagonal of the picture (at least 100 "). However, lamp projectors are not very popular. Why? There are several reasons for this:

• Price. Lamp projectors are more expensive;
• The life of an incandescent projector lamp is limited (about 5000 hours, or even less), and the cost of replacing it is quite large;
• Minimum projection distances (that is, the distance from the projector to the plane on which the image is projected) are usually not less than 1 m, as a result, there is not always the necessary space for installation;
• The need for projectors to have a projection screen (or another plane on which the image will be projected).

Because of these shortcomings, lamp projectors are mainly used as an element of a home theater, and not for ordinary computer work.

Wikipedia will tell more.

LED projectors: salvation has come

Just a couple of years ago, there was a modification of projectors in which incandescent bulbs were replaced with LEDs. Because of this, many of the shortcomings of conventional projectors have been leveled:

• The price of LED projectors is several times lower;
• The life of the LED projectors is several times higher (20,000-30000 hours);
• Some manufacturers (but not all!) Reduced the minimum projection distance to 0.5-0.6 meters. Thus, the LED projector can simply be set in front of itself (for example, on a table) and used as a replacement for the monitor during normal (desktop) work.

If a year or two ago the number of models on the market was limited, then today there is already something to choose from. Even there are models with built-in batteries for battery life, with USB / SD readers, with Android on board.

So what we have.

And we have the fact that today, for $ 500, you can buy a device to replace harmful LCD screens. Long live the revolution!

According to my personal feelings, projectors are still worse for the eyes than e-ink, but much better for LCD screens. Of course, the individual features have not been canceled. So you need to try to work behind the projector to find out whether it will be better for your eyes.

As for the projection plane, it can be any. Ideally, this is a projection screen (but, for some reason, they are made exclusively for large diagonals from 80 "). You can project on white paper. Or on a white wall. The main thing is that the color of the plane is white, and the whiter the better .

What else is wrong

Since LED projectors are only a few years old, this technology has its drawbacks.

1. Perhaps the biggest is the noise level (from 25 to 32 dB). Working at such a noise is uncomfortable, especially considering that the projector, as a rule, should be placed not far from itself.

2. The resolution of most LED-projectors - only 1280x800. FullHD models are also there, but they are still indecently expensive. There are cheaper models with even lower resolution, but I think it will be inconvenient to use them to replace the monitor.

3. Light transmission of LED-projectors is significantly lower than in conventional tube-based projectors. The first models had only 200 lm, which made work in a bright room almost impossible. More modern (and expensive) models have a light flux of 700 lm, and if the projector is placed not very far from the projection plane, the light output will be good enough. But do not forget - the closer the projector, the smaller the diagonal of the picture.

4. If you put the projector in front of you (for example, on a table), you need to take into account such factors as: minimum projection distance and projection ratio. They are not always suitable for this (desktop) format of using the projector, so you need to carefully study the specifications of the device. On the Internet, there are calculator sites for projectors that calculate the size of the diagonal of the projected image depending on the distance and model, Google can help. Notes:

• As I have already said, the majority of manufacturers set the minimum projection distance (for some reason) at the level of 1 meter or more. But there are models with a minimum distance of 0.5 meters. I have not met less.
• The projection ratio is the ratio of the projection distance to the diagonal of the projected image. That is, how many inches of the picture we get, depending on how far we put the projector. The best that I saw is 0.9, that is, at a distance of 1 meter, the diagonal of the image will be 1.11 meters.

Total

Like any technology, LED-projectors have their advantages and disadvantages. The advantages are (subjectively) greater safety for the eyes, compared with LCD screens, and a high reaction rate together with a color image, as compared with e-ink. Among the shortcomings inherent in this stage of technology development, we can distinguish: the noise level, a relatively small maximum resolution (in non-premium models), a relatively low light flux. In addition, the minimum projection distances and projection relations are not as good for “desktop” work as we would like. But you can (and should) put up with all the flaws, since the vision, especially for you,% username%, is the most valuable.

I hope you are interested in the topic. This is my first article, comments are welcome.