What Is a Portable Projection Screen?

The so-called portable projector, also known as a pocket projector, mainly uses the 3M LCOS RGB three-color projection light and decoding technology to make the traditional huge projector compact and portable, making the projection technology closer to life and entertainment.

Portable projector

The so-called portable projector, also known as a pocket projector, mainly uses the 3M LCOS RGB three-color projection light and decoding technology to make the traditional huge projector compact and portable, making the projection technology closer to life and entertainment.

Chinese name

Portable projector

Foreign name

Protable Projector

Alias

Projector, portable projector

Application area

Home, office, school and entertainment

Usually for

Advantage:

1. Small size, light weight and easy to carry.

2. Low heat generation and low noise.

3. The price is relatively cheap.

4. Most models support wireless projection via software.

Disadvantage:

1. Endurance is insufficient, most of which lasts no more than 3 hours.

2. The interface expansion is insufficient. Most of them only have HDMI and USB interfaces, and do not support VGA, DVI, DP and other interfaces.

3. Lumens are inadequate, most of them are generally low, and low prices are generally below 500 lumens, and people can clearly see that the projection content is not less than 3,000 lumens during the day without pulling the curtains.

4. The resolution is insufficient. Most of the resolutions are 720P, and a few models support mainstream 1080P. The screen contrast is more than 4: 3, not 16: 9 or 16:10.

Summary: If it is a fixed place such as a school, government unit, company, etc., it is recommended to use a traditional projector. If you are traveling for business or personal use, you really need a portable projector. It is recommended to choose one with high lumen and high resolution.

If you know something about the projector, you should all know that the main working principle of the projector is to emit light from the light source. Through a series of optical lighting systems, the light from the light source is evenly illuminated on the display chip, and the signal passes through the circuit system Color levels and gray levels are implemented on the display chip to display the image. Thereafter, the projection lens on the front end of the projection projectes the image on the display chip to the corresponding screen. In projection systems, optics are mainly divided into imaging optics and illumination optics, and the most critical components are display chips and lighting components (ie, light sources). Therefore, portable projectors can be classified from 2 aspects:

1. Classified from the perspective of light sources, micro-projections can be divided into

   1. size

   2. Photoelectric efficiency: the luminous flux (lumens) that can be output per unit power consumption (lumens). This indicator is an important indicator for micro-projections. As a general projector, due to the power supply, the general brightness is its very important indicator. It is necessary to take into account system problems such as brightness, battery life, heat dissipation, etc. Therefore, it is not simple to use brightness as its key index.

   3. Resolution: The resolution of the chip, such as VGA (640 * 480), QVGA (320 * 240), etc.

   4. Color purity: an indicator of color expressiveness, which is usually measured internationally by the color gamut range of NTSC e). Contrast: an index that measures the resolution of an image (simple definition of the bright state and dark state ratio of the display)

   DLP technology compared with LCoS technology Speaking of the advantages and disadvantages of DLP technology and LCoS technology, in fact, in the conference room (education) commercial projectors used, there is a dispute about DLP technology and LCoS technology. Of course, as a miniature projection, although The principle is similar, but because the implementation methods are slightly different, there are still some differences. The following will also make a detailed comparison from the foregoing technical indicators.

   1. Size: The final product size of the two technologies is basically the same, without much difference. From a chip perspective, due to the booming liquid crystal industry, the realization of LCoS is mainly a standard liquid crystal packaging process, and the circuit is roughly realized by some ITO glass printing. The DLP micro-mirror array is implemented mechanically, and each micro-reflection There is a very complicated mechanical structure under the mirror pixel, so the reduction of the pixel pitch has a very high requirement on the process improvement. The difficulty is relatively greater than the implementation of LCoS.

   2. Photoelectric efficiency: The brightness efficiency achieved by the two technologies is about the same, with a light output of 7, 8 lumens per watt. However, from the perspective of the two technologies, the signal requirements of LCoS can be directly accessed by the circuit, and because DLP is implemented mechanically, on the motherboard carrying the DMD chip, there is a corresponding processor and memory. (Memory). This part of the power consumption can never be avoided in the overall light engine. It can be considered as a disadvantage of DLP technology in efficiency, especially in the handheld projection overall system. If you consider the heat dissipation problem, the advantages of the LCoS chip are more obvious. . Relatively speaking, the power consumption of LCoS can be less than 0.1W. In the long run, LCoS will also have certain advantages.

   3. Resolution: With the same size, DLP needs to improve the resolution on chips of the same size. It also has very high process requirements. As can be seen from the first-generation DLP light engine, the resolution of 320 × 480 is already 640 × 480 that lags behind LCoS. Although 800 × 480 chips were introduced in the second generation, it still lags behind LCoS technology. From a purely technical perspective, LCoS has a better development prospect than DLP.

   4. Color purity: LCoS is achieved through technological progress and color sequence. The theoretical realization of hair style has been basically the same, so the color purity has been basically the same, which is higher than that of monitors and televisions.

   5. Contrast: DLP is reflected by micro-mirror, and LCoS is realized by the liquid crystal twist to achieve the optical switch. At the time when the light is turned on completely, the liquid crystal always has the problem of dark light leakage. Similar to traditional business projectors, DLP has the advantage in contrast Miniature projection still exists, but in actual use environment, due to the impact of external light on the contrast to the micro-projection is greater, therefore, the advantages of DLP in contrast relative to its commercial projector is correspondingly weakened. In addition, the 3M company's special PBS material mentioned above can achieve a contrast ratio of 250: 1, and 500: 1 with DLP technology, even in a completely dark environment, it should be said that there is not much difference.

   6. Industry: Because DLP is a unique technology of Ti company, the industry uncertainty is relatively large. Compared with several arguments of LCoS, and from the perspective of technology, LCoS should be based on its unique semiconductor industry foundation in the future There is a lot to be done. In summary, the author believes that in the long run, if Ti Company does not have a major technological breakthrough or a better market strategy, in the future, with the blowout of the micro-projection industry, LCoS will have an advantage over DLP technology and use special polarized light. The performance of the LCoS light engine that controls the film is slightly better than DLP. With the advancement of technology, I believe that as a more open LCoS platform, it will definitely perform well.

   LED light source and laser light source, LED light source technology develops rapidly, and is widely used in lighting, home appliances, IT products, and industrial equipment, which not only improves product performance, but also contributes to energy conservation and environmental protection. For the projector, with the improvement of LED light source technology, it will also usher in a new industrial application.

   LED Portable Projector LED

   Light Emitting Diode (LED) is a solid-state semiconductor device that can directly convert electrical energy into visible light. It has the advantages of easy control, low-voltage DC drive, rich color performance and long service life after combination. It has been widely used in urban engineering, large-screen display systems, liquid crystal displays, and LCD TVs. Especially after the application of LEDs in LCD TVs, as the LED industry has grown in the display field, the development of LEDs has also followed the well-known Moore's Law, a geometric development, cost, efficiency, industrial chain, and so on. , Is already very mature, I believe that in the miniature projection industry, will also shine!

   Portable projector laser

   As another type of handheld projection light source technology, Microvision is the main representative company of the technology. In 2009, it launched a miniature projector for laser light sources. As far as the laser light source is concerned, its overall imaging effect is better than that of most projectors implemented by LED light sources, but it also has the problem of imaging speckles. In addition, the high cost has become a major bottleneck restricting its commercialization. Furthermore, due to the safety of the laser itself to the human eye, the difficulty of promotion in the major consumer electronics market of micro-projection can also be imagined. On the whole, without a significant reduction in cost of laser light sources, the short-term prospects cannot be compared with LED light sources.

   As you can see in the introduction above, LEDs have incomparable advantages in terms of cost, industrialization, security, industrial chain, etc. These advantages are in the short term of the rapid development of LED. I believe that lasers are difficult to surpass, but As a laser, it has the advantages of imaging quality and auto-focus function, and it is expected that it will have a greater breakthrough in the near future.