#dlpprojector

As known, the cost of TVs with a large diagonal does not decrease. Models with a screen of 60 "or more are quite expensive. Probably, this trend will not change significantly in the near future. Today, companies continue to increase their resolution (8K, 10K), supported color depth (10-bit and 12-bit color grading with HDR 10+, Dolby Vizion, HLG (Hybrid Log-Gamma) support), HDMI 2.1 (48 Gbps) connection standard, HFR (high frame rate) format, etc. For example, a presented at CES 2019 new LG Signature Rollable OLED TV with flexible screen amazed the most imperturbable viewers.

In addition, companies are constantly improving the technologies of matrices. For example, Nano Cell and Micro LED technologies perfectly illustrate this trend. Unfortunately, the cost of innovative TVs is also increasing. For example, the gorgeous LG OLED 8B 2018 is positioned as a “budget” model due to the price of less than $ 1000. On the other hand, the projector segment is also not standing still. Today, the companies offered quite a lot of 4K HDR models, including Optoma UHD60, BenQ HT3550, Epson 4010, etc. At the same time, the cost of Epson Home Cinema 4000, for example, does not exceed $ 2,000. Given the projection diagonal size (from 150 to 300 inches) and its quality, the appeal of this solution increases for many consumers. As a result, modern projectors have become a good alternative for many users. Of course, the screen 300" is impressive compared to the traditional 50-60".

ViewSonic PRO7827HD

In addition, companies traditionally lower prices for their previous models. As a result, the market offers excellent models at a fairly reasonable price. Of course, the ViewSonic PRO7827HD refers to this type. Today, its price on Amazon is only $ 750. Image quality of Full HD format provides enough comfort for viewing even on a large screen. Video hosting and online services have long offered video in this format. Of course, their assortment is much wider compared to 4K-content. Therefore, Full HD models are still very popular for home theater. UHD projectors of 4K format are actively promoted in the market. However, the limited amounts of 4K-content and cost of these models limit process. Therefore, UHD projectors remain an exotic novelty for most users. Black plastic, glossy stripes and a matte surface give the projector a stylish design that fits perfectly into any interior.

The projector has a relatively small size, but weighs more than 5 Lb.

ViewSonic Pro7827HD has a resolution of 1920x1080 and supports 3D. Сontrols on the upper surface and remote control provide easy and convenient navigation.

Additionally, projector provides connection of analog and digital sources. It has a hidden compartment with HDMI / MHL, two HDMI ports on the rear panel (including one with MHL) and USB to connect wireless modules.

Key features

According to spec, model provides 2200 ANSI-lumens. But testing demonstrates up to 1400 lm in colors and up to 1744 - in white. However, this brightness provides enough image quality even without full dimming in diffused daylight. Color brightness reaches 80% of the white brightness in dynamic mode. BrilliantColor value in the additional image settings reaches 10, that corresponds to the maximum white magnification. But standard mode uses 4. Respectively, maximum brightness decreases in this mode up to color brightness. ViewMatch and Film (Rec.709) modes do not use BrilliantColor (BrilliantColor value=1). Thus, the dynamic mode is designed for less darkened rooms; Standard and Film (Rec.709) modes are optimal for rooms with good dimming. ViewSonic Pro7827HD demonstrates an excellent level of "honest" contrast ratio for this segment (measurement method-full on/full off ). It reaches 1300:1 in the film (Rec.709) mode. Projector supports sRGB and Rec.709 color standards, has ISF certified calibration mode and a special profile for movies. As known, certified calibration (ISF- Imaging Science Research) provides an almost perfect picture.

Moreover, acoustic system with a power of 10 W provides a very clear sound with SonicExpert technology. Sound tract uses a modern sound-emitter, providing high sound quality with an optimum sound response. The audio system is configured in Sonic Mode. Projector also uses SuperColor technology to extend the color range. SuperColor RGBRGB technology provides a very realistic image due to excellent display of color gradients. The RGBRGB color wheel in conjunction with dynamic lamp control ensures acceptably high image quality even at bright enough lighting.

Pros & Cons

Unfortunately, ViewSonic Pro7827HD has the rainbow effect, which is present in almost all single-matrix DLP projectors. As known, this effect forms red-green artifacts along the contour of high contrast objects.

As known, the light source is one of the main and expensive elements of the projector and significantly affects its choice. Its cost can reach 20-30% of the model value. The power of the light source directly affects the projector brightness. In turn, the brightness affects the requirements for dimming. For example, a low-power portable projector with a brightness of up to 100 ANSI Lm can provide acceptable quality only in a dark room. A powerful 3LCD projectors with a brightness of 2500-4000 ANSI Lm work fine even in diffused light without additional dimming. Unfortunately, even such models do not provide acceptable quality in direct sunlight. But, a powerful lamp requires effective cooling. Therefore, such projectors usually have a fairly high noise level due to a powerful fan. Modern projectors use mercury or xenon lamps, semiconductor (LEDs and laser LEDs) or hybrid light sources.

Lamps

Most projectors traditionally use UHP (Ultra High Efficiency) mercury lamps as a light source.

They combine a relatively low price, ease of replacement and high brightness. The approximate life of modern lamps reaches 3000 - 5000 hours in maximum power mode, and their power varies from 200 W and more. The lamp generates a stream of white. Special color filters in 3LCD projectors or in the color wheel of DLP models divide it into red, green, blue, etc streams. Unfortunately, UHP lamps provide white with a green tinge. Usually, companies compensate for the excess green with optical filter or by limiting its brightness. For example, many models use Dynamic or Cinema image modes. The first mode uses maximum brightness, but with a green tint, and the second mode provides more accurate color rendering, but with reduced brightness. High operating temperature is a major cons of UHP lamps. It requires intensive cooling with a sufficiently powerful fan. Unfortunately, they have a fairly high noise level, which reduces viewing comfort. Therefore, this value is one of the main projector specifications. Setting the optimum lamp brightness mode has a slight delay. Reducing the brightness of the lamp over time also applies to their disadvantages. However, today these lamps are a proven, high-quality, bright and inexpensive projector light source. Powerful xenon lamps generate a more balanced white with a perfectly even emission spectrum, providing more accurate color rendering.

Unfortunately, they are much more expensive and less effective. However, high-end projectors often use them.

Semiconductor light sources (LED and laser LED)

Modern models are increasingly using semiconductor light sources, including LEDs or laser LEDs. They generate a very narrow emission spectrum with pure rich colors that do not require special filters to separate colors from the white spectrum. Of course, this feature is very important for modern video standards, for example, for Ultra HD. Power and cost are the main differences between laser and LED light sources. Laser LEDs, especially green ones, have a higher cost of production, but they provide much more power.

The brightness of the LED light source usually does not exceed 500-700 ANSI Lm.

As a rule, expensive projectors use laser light sources. Portable models based on one-matrix DLP technology often use an LED light source. The segment of portable (Cube, Pocket, Pico, Mini) projectors today leads in the growth of popularity. These models do not have a color wheel and provide instant response. Many modern projectors have a WiFi module. The miniaturized dimensions with wireless connectivity ensure their outstanding portability.

Additionally, these sources have a huge service life, which varies from 20,000 to 30,000 hours. For comparison, lamps usually work about 5,000 hours. On the other hand, this period corresponds to a daily 2-hour viewing for 7 years, which is more than enough given the obsolescence of the model. The power consumption and temperature of semiconductor light sources are also much lower compared to lamps. As a result, the lack of a powerful fan reduces their size and eliminates noise. But, unlike a lamp, their replacement requires contacting a service center.

Projectors with hybrid light sources (LED / Laser)

The LED light source provides low brightness of the green LED, and the laser source uses an overly expensive green laser. Some models, for example, Casio projectors, use a blue laser instead of a green LED that shines on a green phosphor. In this case, the blue laser simultaneously forms blue and green. But projector must use a rotating color wheel.

The development of digital technologies for several decades provokes the rapid development of almost all segments of consumer electronics. Today, even a relatively simple household appliances is a complex multi-functional device. Smart coffee machines, robotic vacuum cleaners, washing machines, etc with Wifi support and complex algorithms for auto modes perfectly illustrate this trend. Of course, high-tech projectors are no exception. Modern projectors have evolved from simple devices to project an image into sophisticated digital equipment with huge media capabilities. The projector in the smartphone, miniature Pico and Cube projectors, 4K HDR models, etc perfectly illustrate this trend. Modern technologies have successfully solved the problems of their image quality, compactness, brightness, durability, noise and cost. Today, the market already offers 4K HDR models with a price range of $ 1,000 - 1,500. As a result, many consumers increasingly perceive the projector as an alternative to TV, increasing demand in this segment. Of course, companies are adequately responding to the market conditions by expanding their model lines. But the abundance of proposals sometimes complicates the choice of the optimal model. Therefore, even a simplified classification can help solve this problem.

The number of matrices

As known, the projector matrix provides filtering the luminous flux, passing or blocking it. Therefore, the matrix can form only a single-color image. This is fundamentally different from the matrix of the TV or monitor, which forms a color image. Three-color matrixes are not used in projectors for several reasons. First, almost all the first projectors used high-power bulbs with high heat dissipation for illumination. Therefore, the LCD matrix requires very powerful cooling, which affects the noise, size and cost. Secondly, the three-color matrix does not provide an ideal square pixel. A single-color matrix forms a color image, combining three separate images. 3-chip projectors combine the images and display the finished color picture. Single-matrix models alternately project mono-color images onto the screen, creating the illusion of a color image due to the high frame rate. PROS and CONS 1. 1-chip projector is more compact, but uses more complicated and more expensive matrix. 2. 1-chip projector provides lower brightness due to less efficient use of the bulb luminous flux. 3. Playback in 1-chip models is often accompanied by the rainbow effect due to the non-synchronous speed of changing the image color components. 4. A 1-chip projector provides a perfectly accurate pixel shape, which depends only on the projector optics. The accuracy of the borders of the individual pixels in the 3-chip projector depends on the accuracy of manufacturing and placement of the matrixes. This problem sometimes occurs in budget 3-chip models from lesser-known manufacturers.

Light source and sizes

Modern models use UHP (mercury) or powerful xenon lamps or semiconductor light sources (LEDs, LED lasers). Often, vendors use the name of a laser projector for models with LED lasers as a light source. Of course, this is not entirely correct. Developed in 1991, LDT (Laser Display Technology) technology really uses lasers to form images. The working prototype of the LDT projector was introduced in 1997, and the serial prototype in 1999. Today, these models belong to the professional segment of very expensive installation projectors. Laser in the name of DLP and LCoS models only indicates the use of LED lasers as a light source. Of course, the use of only one chip provides the advantage of DLP technology in terms of compactness. Combined with the LED light source, it provides the production of portable projectors. Their enormous popularity even provoked the formation of a separate segment of compact projectors (mini, pocket, cube, pico).

Projection image formation technologies