3 min di lettura
Color representation is probably the most essential aspect of display technology. Content should be presented correctly, vibrantly, and with high contrast. These are all aspects where direct-view LED technology traditionally leads the way, and LCD falls a bit behind. With Barco UniSee II, the ambition was to bridge this gap, and combine the typical strengths of LCD technology (affordability and reliability) with impressive image quality. In this article, we will explain how we do this.
Barco UniSee is renowned for its innovative mounting structure, bezel-less design, image quality and uniformity. All aspects we aimed to keep, and further improve where possible. For image quality, the high-end consumer market traditionally leads the way. However, the requirements for professional products are quite different, so not all innovations can be leveraged. For example, many professional markets are operational 24/7, putting special needs on reliability and ergonomics. So, we meticulously evaluated the possibilities and acquired the rights on a number of these innovations.
Creating deeper and more saturated colors. This is the ambition of Barco UniSee II. However, this is not the forte of conventional LCD technology. Traditionally, LCD technology uses a white LED backlight, and color is added by letting that white light pass through color filters. The LCD layer lets the light pass or blocks it, thus creating the image. The downside of this, is that in order not to suffer from low brightness, colors can never be highly saturated and are restricted to the Rec 709 color space.
Barco UniSee II counters this by using quantum dot (QD) technology. These quantum dots are essentially tiny crystals that emit narrow band colors when lit with blue light. In this way, you can produce highly saturated green or red colors. So, using blue LEDs with a quantum dot film as a light source, you can achieve a high gamut (part of the blue LED light stays unconverted and mixes with the green and red QD light to achieve a balanced white). The drawing on the right shows a cross section of a Barco UniSee II panel, from the mini-LED backlights (bottom) to the polarizer on top. The QD layer is located on top of the glass layer.
Using quantum dot technology highly lifts the color gamut of the video wall. On the graph, you see the differences in the spectrum of the blue LED lights with QD technology compared to conventional technology (graph 1). There are significant boosts in the red and green color ranges (the blue peak is of course caused by the blue LED light used). So, when this light passes through the filters of the LCD cell (graph 2), the color intensity increases remarkably (graph 3).
Conventional LCD video walls work with a limited number of light sources that are always on. The liquid crystal layer either lets this light pass or blocks it. However, it’s not difficult to understand that this blocking is never 100%. There is always some light leaking through, creating a more greyish image. This means that the contrast ratio of LCD panels can be disappointing – especially if watched under angles, or compared to direct-view LED where the individual LEDs can be completely black. Introducing mini-LED chip-on-glass technology is a solution.
Instead of using a limited number of light sources, Barco UniSee II uses thousands of small LEDs. These LEDs are dimmable when needed. So, for dark areas of the content, the LEDs are drastically dimmed, preventing light leakage, and therefore cranking up the contrast and avoiding typical LCD halo effects. In this way, Barco UniSee II reaches HDR (High Dynamic Range) levels.
Sometimes, a part of the content just needs to really stand out. A bright moon, for example. To achieve these bursts of brightness, Barco UniSee II features the ‘peak mode’. This allows you to uplift the brightness up to a whopping 1300 nit for some specific areas of the display (whereas the overall brightness is limited to 800 nit). This is possible by driving mini-LEDs in specific areas at higher voltage (to be shown brighter), compared to surrounding areas where mini-LEDs run at lower voltage (to be shown dark), based on the content. The result is truly magnificent, and the total power consumption of the LCD video wall remains the same.
Although we try really hard to tell you about the exquisite image quality of Barco UniSee II, this is hard to illustrate. After all, you will see these images on your own display and not on a Barco UniSee II – which highly changes the effect. We know we will only convince you if you see it for yourself. So keep an eye out for an open house or tradeshow near you, or request a demo!