#activeshutter3d

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3D projectors

The rapid growth in popularity of 3D video began in the early 21st century. The companies reacted adequately to the demand and concentrated their efforts on the development of this direction. Soon, many TVs already provided support for this feature. Unfortunately, the limitations of 3D content significantly slowed down its further development. As a result, many leading companies limited their efforts in this direction. Later, the release in 2009 of the 3D-movie “Avatar” by James Cameron caused a new wave of 3D popularity. Indeed, the stereoscopic format of the planet Pandora made a huge impression even on the most imperturbable viewers. By that time, there was already a trend to complement their home theaters with projectors. Therefore, companies have made great efforts for the rapid implementation of 3D option in their models. Unfortunately, companies could not agree on a uniform format. Therefore, modern models use polarization or active shutter 3D technologies. As known, the polarization technology divides the image into two pictures using polarizers. Initially, companies used linear polarization, when the plane of the waves direction for each eye are mutually perpendicular. In this case, the two devices project two images with polarization for each eye onto the screen. Special glasses with filters in the eyepieces pass only one polarization. Accordingly, each eye perceives its own image and the brain forms a 3D image from two pictures. The list of cons includes the need to use two projectors and a special screen with a high reflectivity without changing the polarization. In addition, the preservation of the 3D effect requires a straight head position.

Modern 3D technology

To solve these problems, companies have developed a technology with circular polarization and alternate frame projection for each eye using only one projector. It eliminates the disadvantages of linear polarization, but loses half of the light flux, reducing the brightness. This technology generates 3D images by dividing frames for each eye with special glasses. The projector alternately displays images for each eye with a frame rate up to 120 Hz. Active glasses use special LCD matrix, which are synchronized with the projector via an infrared modulator. They block light streams in such a way that each eye sees only part of the image. Of course, the polarization of the image for each eye must coincide with the polarization of the corresponding LCD matrix of glasses. Our brain perceives visual images as a single 3D image due to its inertia. Today, this technology is most actively used in home theaters. Of course, 3D support affects the choice of projector, increasing its competitiveness. Therefore, most modern DLP, 3LCD, and LCoS projectors support tjis option. As a rule, modern models automatically switch to 3D mode with the appropriate signal at the input, determine the standard and correctly display it. The list of major modern formats includes Frame Packing, Side-by-Side and Top-Bottom. Today, 3D format continues to actively develop. For example, modern BenQ projectors use a new DLP chip from Texas Instruments with Triple Flash technology. It provides 144 fps for 3D content (72 fps for each eye), increasing smoothness of playback. This video demonstrates the best 3D projectors in 2019, including Epson Home Cinema 2045, Optoma HD25e, Optoma HD143X, ViewSonic PX700HD and Optoma HD141X. Read the full article

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Features of 3D TVs of various companies

3D TVs are very popular among many consumers. The presence of this function significantly affects their choice of TV. Today the market offers a wide range of 3D models, but, unfortunately, many companies reduce this direction due to a number of reasons. Implementation of 3D technology in TVs from various companies has features. For example, Samsung Company uses only the active shutter 3D technology. Panasonic and Philips companies use both technologies. Almost all LG models have polarization technology.

Samsung Company

This company produces TVs only with an active shutter 3D technology, that has pros and cons. Large vertical viewing angle refers to its main advantages. This value characterizes the maximum viewing angle without distorting the image. This advantage is especially important when viewing in a small room on a small screen by several viewers. However, most people usually prefer to watch 3D content directly in front of the TV. Of course, in this case the viewing angle does not matter much.

Philips Company

This company produces models with using both technologies, but polarization passive technology is more popular. Playback with this technology does not cause discomfort from periodic flicker. 3D glasses are cheap and light. Unfortunately, turning the head while viewing may disrupt the generated 3D image. This instability may be considered the main and only drawback of passive technology. Typically, these models use the P-IPS matrix that displays the largest number of colors and shades and is a most durable. The matrix is an important aspect, because it significantly affects the quality of the 3D content playback.

Panasonic Company

Today, Panasonic also uses the both technologies in their models. Company has released a new model of glasses that is called TY-ER3D4ME.

New glasses weigh only 27 grams without creating any discomfort during the viewing. They easily dress up over of medical glasses. The synchronization method is the main pros of this model. It uses the radio frequency of the Bluetooth protocol instead of synchronizing by infrared beam. Accordingly, the risk of losing synchronization is almost absent when the viewer moves. Additionally, the TV manufacturers with active 3D have finally developed a unified standard. Therefore, this model is interchangeable with the models of the Full HD 3D glasses from other companies.

LG Company

This company has developed its own polarization Cinema 3D technology. It uses circular polarization which is the main difference of this technology.

Light streams rotate in opposite directions for each of the filters. The filters also have an opposite direction of circular polarization. Each filter transmits only the identical polarization. Filter with right circular polarization blocks the light flow with the left polarization. Accordingly, the light flow with the right polarization is blocked by filter with left circularly polarized. Thus, each eye receives its own continuous image. This technology requires a special FPR (Film-type Patterned Retarder) film. This film is located on TV screen and serves as a filter, providing the image with a circular polarization.

Unfortunately, this technology is implemented only in LG TVs. 3D LG models, except OLED, have matrix P-IPS. 30-bit color depth of this matrix displays 1.07 billion of shades colors. Additionally, these models have a Dual Play mode that displays the image on full screen when connect a game console. TV without this option provides only half of the screen. This video demonstrates Cinema 3D technology. Read the full article

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The operation principle of different 3D technologies

Of course, 3D playback in 3D Tvs is very popular among many consumers and greatly affects the choice of TV. Unfortunately, many companies reduce this direction due to a number of reasons. But, today the market still offers a wide range of these models. Today, 3D playback uses anaglyph, active shutter and passive polarization technologies.

3D anaglyph technology

This technology was the first and most popular, but today it gives way to more perfect technologies. In this technology, 3D effect is achieved by encoding image separately for each eye with the help of color filters. Typically, the red filter is used for left eye and the blue filter is used for right eye. Therefore, special glasses have color filters in eyepieces. Each filter matches to the color that is used during image encoding.

Image for red channel falls to the red filter of glasses and is absorbed. The eye is not sees it. This image is reproduced only through the eyepiece with a blue filter. The same occurs in the other channel. The encoded image falls to the blue filter and is absorbed. A red filter passes it to the eye. In fact, each eye through a filter glasses gets the opposite color from two identical pictures that are slightly offset from each other. This creates illusion for the human brain and, respectively, 3D effect. Unfortunately, color filters partially absorb the colors and shades of the spectrum in the range next to red and blue, reducing the color gamut of the image.

Active shutter 3D technology

This technology uses alternating playback of video frames for the left and right eyes. Thus, TV screen at one time shows only one image for the left or right eye.

The image for other eye appears in the next time moment. Special glasses alternately perform the function of shutter for each eye. Opening and closing is carried by feeding current on filters in the eyepieces. Battery is located in the glasses. The high depth of the 3D image is its main advantage. The high cost and weight of glasses due to the battery, eye fatigue due to constant flickering, distance limitations (visible lines disappear at a distance of more than two diagonals) and different viewing angles (178 В° vertically and 90-100 В° horizontally) are the main disadvantages of this technology.

The passive polarization 3D technology

This 3D technology uses different operation principle and does not contain of the power supply in glasses. The formation principle of three-dimensional image is based on the use of linear or circular polarization for light waves. Today IMAX cinemas use this technology. Formation of three-dimensional image uses two images that are simultaneously displayed on the screen. Each image has its own polarization. The images are skipped at different angles through the light filters and are transmitted to the eyepieces of glasses.

Glasses also have own optical filters. They filter the light flow for each eye. The right eye receives the image through one filter, and the left eye receives the image through another filter. Thus, 3D volumetric image is created with the help of two projectors and eyeglasses with special filters. The instability of a 3D image when viewed on a small screen is the main drawback of this technology. Rotating the head relative to the screen can destroy the perception of the three-dimensional image. LG Cinema 3D technology does not have this disadvantage. Cinema 3D uses a circular light polarization with opposite direction for each eye.

But, unfortunately, it's available only in LG TVs. This video demonstrates the difference between passive and active 3D technology. Read the full article

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3D TVs

3D-technology use the operation principle of our brain that perceives three-dimensional image when the eyes see the different image projections. Today, there are several 3D technologies. Many know them as passive, active and anaglyph 3D-technologies. Polarization or passive technology uses the image separation on the screen with the help of a special film. The images on the screen have the left and right polarization. Filter of eyepiece in special glasses transmits only one type of circular polarization (left or right). Thus, each eye sees through the glasses corresponding light wave (image).

Active shutter 3D technology

Active shutter 3D technology uses a different principle. The left and right eyepiece alternately is closed in special glasses. Wherein, the flashing frequency reaches 60 times per second. TV, in its turn, alternately shows the image for both eyes, opening the right filter for right eye and then the left filter for the left eye. Wherein, the synchronization of Glasses and TV uses a radio channel.

Eyepiece lock uses liquid crystals. In fact, each eyepiece of shutter glasses is a miniature LCD screen. Today, active shutter 3D technology is considered the most innovative. It provides the high depth of 3D-image and the opportunity of its control. But almost all modern 3D TVs have adjustable depth of three-dimensional image. Moreover, the quality of the 3D-effect depends mainly from the content. Unfortunately, it also has drawbacks. Firstly, active 3D technology partially obscures the image, that causes eye fatigue at prolonged viewing due to the constant flicker. Additionally, batteries in the glasses creates electromagnetic radiation. Some experts consider these factors unsafe for health. Some users even experience such discomfort, as dizziness and eye fatigue while watching 3D. Batteries also make heavier the weight of glasses, reducing comfort during watching. Additionally, these glasses have relatively high price. This technology also has limitations for distance. The visible lines disappear at a distance of more than two diagonals. Technology provides the large vertical viewing angles (170°) and small horizontal viewing angles (90-100°). This also negatively affect on perception.

Anaglyph 3D technology

Anaglyph technology uses more simple blue-red glasses, but it has a significant drawback. The color filters absorb colors and shades of spectrum in range beside with red and blue. Therefore, this three-dimensional image is paler compared to other 3D technologies.

Polarization 3D technology

Polarization linear technology also has one drawback. Rotating the head relative to the screen destroys the perception of the volumetric image. Additionally, the watching 3D video on a small screen and at a short distance substantially amplifies it. But the big screen in the cinema compensates for this shortcoming. Cinema 3D technology also uses passive polarization. It was developed and implemented by LG Company. This technology forms a 3D image into TV. Therefore, it eliminates the dependence from visual angle and provides the perception of the volumetric image in the any comfortable position. Additionally, the eyeglasses design is simple and they are cheap. Unfortunately, today this technology is only available in LG models. This video convincingly demonstrates the pros and cons of passive and active 3D technology. Read the full article