Next, I will take you to interpret the hardware parameters one by one, so that you can have a deeper understanding of home projectors.
1. Display chip
Choosing a projector first depends on the chip, and the chip size determines the resolution. There is a principle for choosing chips, that is, the larger the chip, the better at the same price.
At present, the home projectors on the market mainly have five chip sizes, namely 0.33 inch, 0.47 inch, 0.66 inch, 0.95 inch and 1.38 inch.
1.38 inch: it is a commercial machine mainly used in cinemas. Due to volume, weight, noise and cost, ordinary users can’t afford it.
0.95 inch: it is used for the top DLP projection of home projector. It is not common now due to the problem of cost performance.
0.66 inch: it can accommodate 4.15 million pixels, and the physical resolution is 2716 × 1528, a 4K DLP chip, is a common chip size for high-end projectors, and the price of configured models is generally more than 10000.
0.47 inch: it can accommodate 2.07 million pixels with a physical resolution of 1920×1080. This size can be used for entry-level pseudo 4K or 1080p. It is the best choice for home projectors.
0.33 inch: it can accommodate 920000 pixels, with a physical resolution of 1280×720. It can only be used on micro projection machines, and the image quality effect is not outstanding.
Through the above description, I hope you can understand that the size of the chip is the most basic parameter to distinguish the grade of the projector. The larger the chip, the better the image quality.
At present, the mainstream chip sizes of household projectors are 0.47 inch and 0.33 inch. Chips of other sizes are not recommended for purchase due to cost performance.
The physical resolution of 0.33 chip is only 1280×720, and 1080p is achieved through image dithering technology. Therefore, when the budget is sufficient, we still need to choose a 0.47 inch chip, so that the image quality can be guaranteed.
The physical resolution of the 0.47 inch chip is 1920×1080, but it can be compatible with 4K resolution through image dithering technology, but it does not mean that the 0.47 inch machine can really show 4K effect.
Therefore, we should polish our eyes in the process of purchase and don’t listen to the propaganda of the manufacturer. The real resolution of a projector only depends on the chip size. The 1080p and 4K effects of some machines are achieved only through image dithering technology. Don’t buy just by looking at publicity. You fall into a trap and waste your money.
2. Display technology
The existing display technologies on the market now include LCD, 3lcd, DLP, 3DLP and LCOS.
LCD: because the color difference is quickly eliminated, only a hundred yuan projector will still be used at present;
3lcd: the main advantage is good color, but the service life is not long. Commercial projectors are commonly used, and household projectors are not common;
DLP: it has the advantages of fast response, long service life and small volume. Household projectors are most commonly used;
3DLP: it is very high-end and achieves the best picture quality, but the price is high, which is mostly used in cinemas;
LCOS: the future development direction is better than 3lcd and DLP, but there are still many technical problems to be overcome and mass production is impossible.
Therefore, the most common home projector display technology on the market is DLP, which can meet all daily needs and is also the most practical one. Some commercial projectors will use 3lcd display technology. Although the color is better, the brightness is low, so it is not recommended.
The resolution of household projectors is mainly divided into the following four types: 4K, 1080p and below 1080p.
It should be noted that the resolution should be viewed together with the chip size, so that it can be better recognized.
4K: resolution 4096 × 2160, that is, there are 4000 pixels in the horizontal direction, referred to as 4K. The 0.66 inch chip also needs a Diagonal displacement through XPR technology to achieve 4K effect.
1080p: it is a progressive scan up to 1920 × 1080 resolution display format, 0.47 inch chip can fully show the 1080p effect. Basically, we download the most movies.
Below 1080p: mainly 720p and 480p. 720p resolution 1280 × 720, chip size 0.33 inches. 480p with 720 resolution × 480, the chip size is usually 0.23 inches. They can show 4K and 1080p effects through dithering technology, which is acceptable to human eyes, but the dithered pixels can be seen through close observation.
Resolution is a very important parameter. The combination of high resolution and high brightness can produce the best viewing experience.
However, the higher the configuration of the projector, the higher the price. Especially the real 4K projector, the price is mostly more than 10000, but the display effect is not as good as the smart TV at the same price. Therefore, in the case of limited budget, 1080p home projector is mainly considered.
4. Projection brightness
Projection brightness is a very important parameter, which is mainly divided into light source brightness and ANSI lumen.
Light source brightness: it is the brightness of the projection bulb itself, which has not been deleted by the lens or other factors.
ANSI lumen: it is the internationally recognized international standard unit of projector lumen, which is closer to the brightness we usually watch.
It should be noted that the brightness of 3500 light source is ≈ 1000 ~ 1200ansi lumens.
Many manufacturers deliberately confuse the brightness of the light source with ANSI lumens in order to give users the illusion of high brightness of their own machines. This should be paid special attention to when purchasing.
5. Projection ratio
When the installation space is more than 4m, the projection ratio is not necessary. However, if the installation space is small, the projection ratio needs to be calculated, otherwise the picture projected by the projector is not large enough and the effect is not good.
The projection ratio of general projector is usually between 1.2-1.9; When the projection ratio is less than 1, it is usually a short focus lens; When the projection ratio reaches below 0.6, it is usually an ultra short focus lens.
It should be noted that the process of short focus and ultra short focus lens is more complex than that of ordinary lens, the accuracy control is more difficult, and the price of projector is higher.
Next, I will briefly introduce how to use the projection ratio to determine the installation distance.
The screen width is determined by the screen proportion. There are two mainstream screen proportions:
16: 9 screen: width = diagonal x 0.8716, height = diagonal x 0.4903;
Example: 100 inch screen
Picture width = 100 x 0.8716 = 87.16 inches = 87.16 x 2.54 = 221.39 (CM)
4: 3 screen: width = diagonal x 0.8, height = diagonal x 0.6;
Example: 100 inch screen
Picture width = 100 x 0.8 = 80 inches = 80 x 2.54 = 203.2 (CM)
Therefore, the projection distance can be calculated directly through the projection ratio.
Take the projector with a screen ratio of 16:9 as an example. If the projection ratio of the projector is 1.5, it is necessary for the projector lens to be 221.39×1.5 = 332.085 cm away from the curtain, about 3.32 m to project a 100 inch picture with this projector.
Therefore, when purchasing projectors, the installation distance should be calculated in advance to avoid the situation that the projection picture is too small.
6. Storage and memory
The operation and storage is the temporary data storage space provided for the operating system and running program of the home projector. The size of the storage is very important. The larger the storage, the more programs can be run and the faster the running speed.
Memory, like hard disk, is responsible for storing and saving data. How many apps the projector can install and store pictures and videos depend on the size of the memory.
For current household projection instruments, 2G + 16g storage combination can ensure smooth use. If it is higher, it will be better.
In this regard, many manufacturers hide their models of operation and storage processors, and even some old projector manufacturers, such as BenQ and Epson, do not have operation and storage processors. They need to be matched with TV boxes and computers to use them, which is very inconvenient.
3、 Detailed explanation of software technology
The content of this part mainly determines whether the home projector you buy is easy to use. Now that smart devices are so popular, many projector manufacturers keep pace with the times and make home projectors like mobile phones, which is particularly practical. Let’s analyze them one by one.
1. Side throw
Many people have limited space or don’t want to lift. They want to support side projection when buying projection. The side projection function of the projector is realized through trapezoidal correction, but is it possible to support trapezoidal correction? The answer is no, and the trapezoidal correction function of the projector is also different.
The side projection of the projector must support the trapezoidal correction in the left and right directions. Only the upper and lower trapezoidal correction can not realize the side projection.
At the same time, the implementation of projector side projection can be divided into two ways: software and hardware.
Software side projection: calculate the trapezoidal angle of the output picture through the GPU of the projector, and then output it to the optical machine for display. The advantage of software side projection is low cost, but the disadvantage is that the speed is slightly slow, the correctable angle is small, the image quality loss is large, and there are obvious sawteeth at the edge of the picture. Most importantly, the software side projection does not support 3D.
Hardware side projection: the projector is equipped with a special trapezoidal correction chip. The commonly used chip is ichipsc788 chip from Japan. The projector equipped with this chip can carry out 45 ° trapezoidal correction at most. At the same time, it also provides image quality correction and adjustment functions, and supports 3D side projection.
Therefore, if you need side projection, I recommend buying a projector with hardware side projection. At present, the flagship projection products equipped with ichipsc788 chip in the home market include dangbei F1, dangbei F1C, dangbei F3 and Jimi H3.
2. Motion compensation
When some students buy projectors, they find that some have motion compensation and some do not, which makes people confused. What is the purpose of this motion compensation function and what is its use?
In fact, if you buy a projector to watch a movie, it is a normal frame rate and does not need motion compensation. If you turn on motion compensation, it is not good, which will affect the fluency of the movie.
If you like watching sports events, people and balls move very fast, such as football and basketball, you need to turn on motion compensation. This function will make the motion picture more smooth.
If the projector you buy has motion compensation function, you’d better turn it off when watching movies, so as to have a better viewing experience.
3. Operating system
Nowadays, intelligent home appliances are the mainstream, but some old home projectors are not equipped with an operating system. We need to use them with TV boxes or computers, which is troublesome to operate. I don’t recommend buying this kind of projector.
Some old home projectors have not developed their own operating system, but also use the native Android system, which is inconvenient to operate and slow. These are also not to be purchased as far as possible.
I most recommend those with their own independent systems, such as dangbei, Jimi, nuts, etc., which are more convenient to use. Just as we use mobile phones, they are particularly intelligent and convenient.
4. Heat dissipation
Many people buy home projectors to watch movies and TV dramas. They watch them for a long time each time, which requires very high heat dissipation. First, they need to protect the LED light source, and second, they need to protect the DMD chip.
In DLP projectors, the cost of optical machine accounts for about 50%, and DMD chip is the “heart” of optical machine. Once the optical machine has problems after most home projector users are insured, the maintenance cost should reach 60% of the whole machine. It’s better to replace a new machine.
The maximum allowable working temperature on the surface of DMD chip radiator is generally within 55 ℃, which can be easily reached if it is used for a long time. Especially for some small brand machines, although the price is cheap, the radiator used is very poor, which is easy to cause problems.
Therefore, when we buy a projector, we must buy a large brand product and consider the effect of heat dissipation. A projector with excellent heat dissipation will naturally have a long service life. At the same time, the daily dust cleaning of the projector should be done frequently to avoid dust affecting heat dissipation.
5. External interface
Many students didn’t look at the home projector carefully when they bought it. When they bought it back, they found that the external interface on the machine didn’t meet their requirements. In particular, some old projector manufacturers didn’t set up a USB external interface and couldn’t plug in a USB disk to watch movies. It’s very troublesome every time they use it.
There are also some machines with USB 2.0 interfaces and some with USB 3.0 interfaces, which makes us confused when choosing. We take it for granted that 3.0 is better than 2.0. We should buy 3.0 interfaces.
In fact, if our resources are only ordinary 1080p, the USB2.0 interface can fully meet your needs, and there is no card when playing. However, if your resources are 4K resources, you need a 3.0 interface when playing, otherwise there will be a slight jamming phenomenon.
So whether you need USB 3.0 interface or not depends on your actual situation. For most people, it is impossible to use it.