New projection technology has been developed to address the limitations of laser and LED light sources

Polar Meter has developed Dual light, a new projection technology designed to address the limitations of laser and LED light sources. Polar Meter is a recently established brand with compact projectors such as the recently updated MoGo range, as well as ultra-short focal products such as the Aura which we measured in this article. Before explaining what pole-meter dual light technology consists of, it is worth understanding why it was created. Pole Meter has experimented with all the technologies available for light sources: from leds to lasers in single or RGB configurations.

Limitations of LED and laser sources

All of the available technologies show specific limitations that are closely related to the characteristics of leds and lasers. For example, a single laser source cannot cover a wider color space. RGB lasers solve this problem, however, because the spectrum of the three color components is very narrow, it is affected by defects that manifest in the form of "spots" and "color edges". Specks appear as a kind of grain covering the image, while colored edges are particularly noticeable at the edges of certain elements, such as text, where colors tend to separate, creating halos and blurring details further.

These limitations relate precisely to the very narrow range that offers advantages but also disadvantages. RGB lasers have the advantage of being able to represent very pure primary color components, thus rendering very saturated colors and being able to approach the coverage of the BT.2020 color space. On the other hand, given that there are no "soft" and continuous transitions along the entire spectrum, the apparent separation can lead to the defects we mentioned. As we have seen in our tests of various products such as the Hisense PX1-PRO, it is possible to mitigate these effects, but so far no solution has been found to completely eliminate them.

In its search for the ideal light source, Ji Mi also considered "full-color" leds. In this case, however, there are also insurmountable technical limitations: the spectrum is not that narrow, and therefore there are no spots or color edges. However, the luminous efficiency is limited, so it cannot produce luminous images as laser projectors do. So the idea is: combine the advantages of LED and laser, give full play to the advantages of both, and fill their respective gaps.

Dual Light Technology, developed with contributions from Zeon Group and Bright Company, offers optics with higher transmittance, or the ability to let in more light. The combined action of leds and lasers aims to achieve synergies that can compensate for the weaknesses of each technology:

Lasers cover a wide range of color Spaces with powerful luminous fluxes that leds cannot achieve

Leds reproduce a spectrum more similar to natural light, eliminating laser defects such as speckles and color edges

However, as Xgimi explains, getting it up and running is no mean feat. In fact, the simple combination of leds and lasers cannot be concretized into the sum of their respective properties: the overlap between the respective wavelengths is destructive, often subtracting rather than enhancing, to the point where Polar is talking about a 1 + 1 situation. 1, that is, the result of addition is less than the starting point. Then there's the second problem: getting two sources of vastly different energy densities to coexist in the same path. Lasers are very concentrated and have high energy, while leds are characterized by large emission surfaces.

Various solutions have been devised to overcome these problems: first, the wavelength of the LED has been modified to limit it in a controlled manner to ensure there is no interference with the laser. A five-channel hybrid laser /LED light path was then created, which was obtained through the special arrangement of the combined light sources and due to the various materials used. Two light sources operate at 5 wavelengths, ensuring wide coverage of the color space, highlight flux, and superior color fidelity. Pole Meter publicly states that Delta E averages close to 1, the invisible error threshold, which is usually guaranteed on professional screens.

These results have been certified by SGS and TUV Rheinland. Polar Rice claims to guarantee them even in mass production, thanks to a platform that can work at every level, from the selection of light sources to the testing carried out after the machine is assembled. Steven Xiao, CEO of Polar Rice, said:

"With the improvements offered by innovative dual-light technology, we believe brightness will no longer be an issue for consumer projectors. However, Kimi believes that this is not enough. Color accuracy is also needed."
Dual Light technology is already available in the first batch of products in China and will be arriving in Europe soon.

Source: Laser Net