About 10 years ago, companies mainly offered lamp-based Home Theater projectors. But the high price, limited content, and dependence of image quality on ambient light severely limited their popularity. Moreover, the last factor seemed insurmountable.
Indeed, even diffused light made the image faded and dull. Of course, increasing the brightness solves this problem. But increasing the lamp power is accompanied by an increase in their heating, requiring efficient cooling and a large enough internal volume to dissipate heat. In turn, powerful fans are quite large and very noisy. As a result, these projectors were bulky and noisy, and their lamp life was only a few thousand hours. Therefore, the developers were forced to limit their brightness. But this solution requires careful darkening the room, which is hardly convenient, for example, in the living room. Perhaps the owner of a spacious villa can allocate a separate room without windows for the Home Theater, but for most ordinary apartments this is an unaffordable luxury.
About 5 years ago solid-state light sources based on powerful and relatively inexpensive LEDs and laser LEDs have radically expanded the possibilities for developers. Unlike a conventional diode, a laser diode has a built-in optical cavity and operates at much higher pump currents. Accordingly, it provides significantly greater brightness. For comparison, the brightness of the first LED projectors varied within a few hundred lumens. The brightness of modern laser light engines reaches 2,000 lumens and above. As a result, the market was quickly filled with inexpensive portable (pocket-, piko-, mini-) low power LED projectors and much brighter laser models.
UST projectors
Sufficiently high brightness already provided acceptable image quality in a normal room without bright sunlight. But traditional medium-throw projectors had another drawback. Placing the projector on a coffee table in the living room creates a wiring problem on the floor, and a ceiling mount is quite a hassle. Recognizing the problem, companies focused on optics for projector. Their efforts were not in vain, and within a few years the market began to fill up with ultra-short throw projectors that projected images of 100 inches or more from several tens of inches.
These models mainly use lens with folded optics (Epson lens which two flat mirrors) or with a concave aspherical mirror (large-diameter aspherical lens on the exit side reduces chromatic aberration).
Lens spherical aberration.jpg
Today companies are actively developing new UST models. For example, this year, their list has been replenished with:
– Hisense PX1 and PX1 Pro ‘laser TV’;
– LG CineBeam HU715Q and HU915QE;
– JMGO U2;
– Viewsonic X2000-4K.
All models use triple-laser or laser phosphor light engine. In the first case, colors are formed using RGB lasers without a color wheel and, accordingly, without loss of brightness.
Laser phosphor light source uses a blue laser diode, which additionally is used to illuminate a yellow phosphor wheel. Then, yellow is split into green and red with a prism or color wheel.
Triple-laser technology is brighter and more expensive.
Until recently, LED light engines were only used in portable models due to their low brightness.
UST projector vs TV
The expensive but highly efficient UST ALR screens, streaming services and the development of screen mirroring technologies finally opened the way for laser UST projectors into living rooms as an alternative to TV. Today some sellers often call them ‘living room projectors’.
Of course, the brightness of the direct light flux of the TV is radically higher vs projection light reflected from the screen. For example, Samsung this year introduced Neo QLED QN95B, which has a peak brightness of over 2,000 nits.
By comparison, even bright home projectors provide several hundred nits for 100-inch projection. But laser UST projectors cost several thousand and offer screen sizes of 100 inches or more. For comparison, the price of huge TVs 2022 today is:
– cheapest 98-inch TCL 98R754 4K – $ 8,500;
– 98-inch Samsung QN90A – $ 13,000;
– 100-inch Sony BRAVIA XR X92 – $ 17,000.
But brightness is primarily needed for HDR content, which is currently only available through Disney Plus, Netflix, or on 4K Blu-ray. But most viewers receive SDR content via cable or satellite TV, which does not require too high brightness for high quality playback.
The combination of these factors causes the growing popularity of UST projectors.
OSRAM Ostar Projection Power LED
As known, a multinational OSRAM Licht AG company, headquartered in Munich, Germany, develops and manufactures semiconductor components, lighting equipment and intelligent lighting systems. At CES 2020, it unveiled 12 new Ostar Projection Power products for LED technology raising projector brightness levels to an unprecedented 3,000 lumen (lm).
Their various combinations form several power classes:
– deep blue (440 nm);
– blue (456 nm);
– converted green (520 nm);
– amber (614 nm).
In turn, their combinations provide:
– two chips of the same color per LED – 1,500 ANSI lm;
– four chips of the same color per LED – 2,500 ANSI lm;
– six chips of the same color per LED – 3,000 ANSI lm.
According to the company, the performance jump was mainly achieved through improvements in chip and package technology based on third-generation LED curing lights.
In fact, they can turn on/off four peripheral LEDs with the lower wavelengths, increasing the overall chip brightness.
Using a serial electrical connection on the copper board, the developers have radically modified the operation of individual LED chips. This solution reduces the operating current with the same power consumption, simplifies the LED driver and improves its contacts. Moreover, it supports direct coupling of the LEDs to a heat sink without additional isolation. Finally, the company has not changed the mechanical design to provide interchangeability for existing projector systems.
Of course, this innovation has not gone unnoticed. One of the industry leaders, the American ViewSonic Corporation headquartered in Brea, California, correctly assessed the excellent prospects of new OSRAM’s Ostar Projection Power family. Company has developed 3rd generation LED technology based on new LEDs. It increases the brightness of LED projectors up to 3,100 LED Lm at 125% Rec.709 wide color gamut.
3rd generation LED technology
But the declared brightness of the new technology has nuances. Of course, competition encourages companies to focus consumers’ attention on the pros of the technologies used. For example, Sony specifies the Color Light Output (CLO). It’s always equal to white color due to the absence of losses on the color wheel, which is not used in 3LCD projectors.
In turn, DLP projector manufacturers offer to take into account the Helmholtz-Kohlrausch effect, which takes into account the perception of highly-saturated colors as brighter by the eye. To draw the attention of consumers to this aspect, they often specify the brightness of their models in LED Lm instead of the traditional ANSI Lm. But in fairness, it’s relevant only when compared with lamp models, the color saturation of which is much lower.
Physically, the difference is due to the location of the brightness measurement
.
Of course, measurement results vary.
Based on manufacturers public data, 1,000 LED lumens converts to approximately 417 ANSI lumens. However, the different units of measurement sometimes creates confusion. For example, on ViewSonic website the brightness of new LS500WHP / LS550WHE is 3,500 / 3,000 ANSI lumens. But the X1/X2 with identical light engines provide only 3,100 LED Lm, or less than half. But even if their real brightness exceeds 3,000 LED Lm instead of specified 3,000 ANSI Lm, ~ 1,500 ANSI Lm brightness is also unprecedented for LED light engines.
ViewSonic X1 & X2
This spring, the company announced the new X2000B-4K laser UST projector. But it was not the only novelty. In early summer, ViewSonic additionally announced new X1 and X2 high brightness LED projectors with built-in Harman Kardon speakers based on innovative 3rd generation LED technology with OSRAM Ostar Projection Power LEDs.
They provide an unparalleled brightness for LED light engines of over 3,000 LED Lumens (~ 1,500 ANSI Lm). It’s already sufficient for acceptable image quality even in diffuse daylight when using UST projectors as an alternative to TV.
With a price of just over $ 1,000, projectors have a Full HD resolution, 3,100 LED Lm brightness, 3,000,000:1 dynamic contrast ratio, 125% Rec.709 wide color gamut, two 6.0W Harman Kardon speakers, lens shift control knob for vertical image adjustment, 4 corner adjustment and 1.2x / 1.3x optical zoom lens. They support screen mirroring via embedded WiFi modul, Bluetooth connectivity, Full HD 3D and HDR.
Optics
Mid-focus X1:
-Throw Distance – 6,5 ft – 12,5 ft (2.0 m – 3.8 m);
-Image Size – 60″ – 150″ (152 cm – 381 cm);
-Throw Ratio – 1.15:1 – 1.50:1 (D:W).
UST X2:
-Throw Distance – 2 ft – 15 ft (0.6 m – 4.6 m);
-Image Size – 60″ – 120″ (152 cm – 305 cm) / (100″@1.53m);
-Throw Ratio – 0.69:1 – 0.83:1 (D:W).
Of course, many UST models with a Throw Ratio of ~0.2 :1 form 100″-150″ projection when placed next to the screen. The X2 produces a 100″ projection from 1.5 m. This is enough to fix the problem of wires on the floor in the living room center. But, in fairness, it’s more in line with short-focus models.
Resolution
The projector uses a .65″ DMD chipset by Texas Instrument with (1,920×1,080) resolution.
Perhaps the use of a 1080p chipset may seem controversial. The difference between 4K and 1080p projectors has been discussed many times and includes:
– 4K projector is more expensive, has a higher resolution, uses more streaming internet data, and increases the viewing quality within 10ft;
– 1080p models are cheaper, often have a higher contrast ratio, and image quality does not depend on the viewing distance. In addition, the range of 1080p content is virtually unlimited unlike 4K content.
Some ‘4K-ready’ projectors can receive a 4K signal, downscale it to 1080p, and display it on the screen. This option is useful, but it only expands the available content without providing playback in 4K resolution.
Until a few years ago, projectors with native 4K resolution were significantly more expensive. Accordingly, the choice of developers in favor of 1080p chipsets was usually driven by the desire to reduce the model price. But in recent years, the situation has changed due to the improvement of pixel shifting technology. Unlike ‘4K-ready’ models, it allows the 1080p chipset to display an image at a higher resolution, creating additional ‘copies’ of it by shifting pixels diagonally. DLP XPR technology in DMD (Digital Micromirror Device) from Texas Instruments was a revolutionary breakthrough, opening the way to the market for relatively inexpensive DLP projectors with real 4K support.
DLP XPR technology
The idea of pixel shifting is simple and captivates with its elegance. Like the frame interpolation in TVs, the projector creates a duplicate image with a vertically and horizontal shift of half a pixel. As a result, our eye sees more pixels and perceives the image more clearly.
A few years ago, Texas Instruments introduced an .66″ chip (2,716 x 1,528) with two-phase pixel shifting and a micromirror pitch of 5.4 µm. In 2017, the company introduced the .47″ (1,920 x 1,080) DLP chipset with four-phase pixel shifting, increasing the number of displayed pixels to 8 million. Finally, TI introduced the latest 4K DLP650TE chipset, which combines four-phase pixel shifting and increasing the micromirror pitch from 5.4 µm to 7.6 µm.
Projectors with these chips use XPR module with four electromagnets, which very fast tilt the lens in the vertical and in the horizontal axis, shifting the image on the screen by 4 times per second.
Simply put, this technology takes 4K content, splits it into four parts of 2 million pixels each, and plays 4 separate frames, transmitting the entire 4K volume with the help of only 2 million pixels of 1080p chip. Strictly speaking, at any given moment, the 1/4 part of the image contains only 2 million pixels (1080p resolution). Then, the projector plays the next 2 million pixels at a 1/2 pixel shifting, etc. But our vision and brain do not perceive the micro-delay between their switching, creating the illusion of a holistic image.
Unfortunately, the XPR DLP chip increase the price of the projector. For example, BenQ 4K X3000i is more expensive vs 1080p BenQ X1300i at $ 700 ($ 2,000 vs $ 1,300). Perhaps this aspect was decisive for the management of ViewSonic.
Conclusion
This year, the UST projectors list has already expanded with new 4K models, including:
– Hisense PX1 and PX1 Pro ‘laser TV’ – $ 2,500 and $ 3,150 (triple-laser light engine);
– LG CineBeam HU715Q and HU915QE – $ 2,900 and $ 6,000 (laser phosphor light engine);
– JMGO U2 – $ 3,000 (RGB laser light engine);
– Epson LS800 – $ 3,500;
– announced Viewsonic X2000-4K – $ 2,900 (laser phosphor light engine).
The new ViewSonic X2 joins the list of ‘living room’ projectors. But, of course, it differs significantly from competitors. Firstly, it uses an LED light engine, and secondly, its resolution is only 1080p. These factors provide X2 with a fantastic gain in price. At just over $ 1,000, it’s about three times cheaper vs competition. At the same time, its brightness of 3,100 LED Lm and 125% Rec.709 color gamut with 3rd generation LED technology provide a fairly high image quality.
Considering the price ratio of BenQ X3000i 4K and BenQ X1300i 1080p, the price of its 4K version may be slightly higher than $ 1,500. But, of course, the company can only make such a decision if 1080p X2 is a marketing success. In this case, they could be the first budget UST LED ‘living room’ projectors. What’s more, the $ 1,000 – $ 1,500 price range is quite in line with, for example, mid-budget 65-inch TVs. But at the same time, the projection screen size is twice as large, which can be a decisive bonus for fans of the huge screen.
This video introduces the new ViewSonic X1 & X2 projectors.