Many still remember earlier days with bulky tube devices. The LCD technology for monitors has just 24 Years under their belt and also quite hesitantly prevailed. Today, a high-resolution flat screen is so much part of normal office equipment that you would rather notice its lack. Time to take a look at the development of less than three decades.

In spring 1994 reported c’t from a 10, 4-inch color monitor with VGA resolution (640 × 480 pixels), which is for proud 10. D-Mark was offered. The exorbitant prices in spite of the miserable resolution and enormous dependence on viewing angles were due to the immature LCD production – at the time there were rumors of reject rates 70 Percent.

In the following two years the first LCD monitors came with 15 inches diagonal to the market, the resolution increased to 1024 × 768 pixels (XGA). At over 4800 D-Mark, the devices were still extremely expensive. In the 1990 in the years, voluminous tube monitors (CRT, Cathode Ray Tube) dominated the desks: good devices with 20 Inch diagonal set 1280 × 1024 Image points (SXGA) on a visible image area with 18 inch diagonal – part of the picture surface disappeared behind the tube surround.

LCD monitors initially only analog LC displays were able to do theirs The advantage over CRTs – a flicker-free, crisp display – does not initially play out because they are operated in analogue mode just like CRTs. The monitor manufacturers had to re-digitize and synchronize the analog video signals from the graphics card. Several LCD monitors flickered because of this.

At CeBIT 1998 were finally presented the first graphics cards that had digital signal outputs in addition to analogue outputs. In the same year, c’t tested LCD monitors on a large scale for the first time – twenty devices with diagonals between 13 , 8 and 15 inch for 2700 to 4800 D-Mark. Their viewing angles were extremely narrow – when viewed from the side, the image was milky, viewed from below it was often inverted. The flat displays were celebrated anyway.

The first purely digital LCD also took part in the said comparative test: Siemens-Nixdorf supplied it with one matching graphics card, it showed 1024 × 768 pixels to just 35 Centimeter (13, 8 inches) in the diagonal and cost a proud 3700 D-Mark.

The first purely digital Monitor from Siemens-Nixdorf, the MCF 3501 T, was delivered with a graphics card.

The first 18 – Zöller came in the middle 1998 to the c’t laboratory. They came from NEC and Eizo and cost 6000 D-Mark four to six times as much as one Comparably large tube monitor. Your screen size was rated as great, the image quality was only medium. In the following years, prices fell rapidly, which the supermarket chains also took care of – monitor offers provoked queues in front of Aldi, Plus & Co. at the time. A 15 – Zöller cost middle 2001 only 700 D-Mark. However, most of the devices used TN panels that were dependent on the viewing angle and only had an analog signal input. Only from about 2003 monitors with VA and IPS technology with stable viewing angles became affordable.

Digital connections are changing the time: P&D, DFP, DVI, HDMI, DP, USB-C (from left)

Growing diagonals and above all higher resolutions finally forced the switch to digital input. As is usual with many fundamental changes, this switch resulted in a jumble of digital connection options, including P&D, DFP and DVI. For Apple’s own DVI variant ADC, you even needed your own, very bulky power supply. In the entertainment electronics segment, the High Definition Multimedia Interface (HDMI) ultimately prevailed, while the DisplayPort asserted itself in the PC sector. Many PC monitors also offer HDMI, some even VGA.

Some LCD manufacturers from the very beginning are still represented on the market today, such as BenQ, Philips and Samsung. But do you still know Belinea, Natcomp or Highscreen?

LEDs instead of cold cathodes A milestone was the change of the backlight: Instead of cold cathode lamps (CCFL, Cold Cathode Fluorescent Lamp), 2006 small Light emitting diodes (LEDs) illuminate the LCD background. First, the manufacturers used colorful RGB LEDs in the backlight, which made the monitors extremely colorful, but also extremely expensive.

The first inexpensive blue LEDs, whose light was converted into “white” light via yellow diode caps was found from about 2008 in monitors. While the LED backlight has long been common in notebooks, the complete switch to the more energy-efficient LED technology in PC monitors only took place after 2010 . With the mercury-containing CCFL tubes, the shimmering in the screen background also disappeared, the monitor housings became lighter and the displays even thinner.

3D -Displays and wide formats From 2009 there was a 3D intermezzo : Monitors whose stereo images could be viewed by users with red-green glasses, bulky shutter glasses or lighter polarized filter glasses – and cumbersome driver settings. In the same year the format of the flat screens changed from 4: 3 or 5: 4 to wide formats like 15: 9 , 16: 9 or 16: 10. This was not due to the changed viewing habits of the users, but simply to new panel factories: In order to utilize the fabs for wide-format flat screen televisions, monitor panels were also produced there.

3D monitors found End of 2000 years also with c’t great approval.

More pixels The full HD resolution already common in TV with 1920 × 1080 Pixels then also caught on in monitors. From about 2010 were 27- and 30 – Inch screens are offered with even more pixels, namely with 2560 × 1440 (15: 9) or 2560 × 1600 Pixels (16: 10).

2012 The first high-end devices with ultra-high resolution (UHD, 4K) such as Eizos FDH 360 For 25. 000 Euro in trade up, down 2013 the 4K resolution for monitors became more affordable. The initial connection problems soon subsided and the prices also fell quickly: Two years later, 4K monitors with TN panels cost just 500 Euro.

With the resolution, the screen diagonals increased – 32 – Zöller with 80 centimeters Diagonals suddenly became conceivable for the desk. c’t therefore checked in in the spring 2015 whether the cheaper 4K TVs can also be converted into large monitors.

Approximately from 2013 came oversized monitors with 2560 × 1080 or even finer 3440 × 1440 Pixels in fashion. Many of the screens were slightly curved in order to keep the distance between the screen surface and the viewer’s eye constant. The wide displays were initially smiled at – today they are indispensable.

2015 Apple, Dell and HP presented the first 5K displays with just under 15 Millions of pixels, two years later Dell triumphed again with the first 8K monitor doubled 32 millions of pixels. Such giants are still reserved for a few, very expensive devices.

Displays for gamers Likewise 2015 Gaming fans were delighted with the first monitors, whose image output synchronized with that of the graphics card delivered frames ran. For Nvidia’s G-Sync, the monitors required a fan-cooled module that ensured synchronization. For AMD’s FreeSync, a variant of the vo In the Adaptive Sync specified by VESA, there was no need for an expensive module – there were initially no displays for both technologies. This camp formation only ended 2019 , when Nvidia had an appreciation and presented so-called G-Sync compatible devices.

2017 the USB-C port found its way into the monitors as a video input. Since it also transmitted USB data and power in addition to DisplayPort video signals, the monitors could be used as docking stations for notebooks.

High contrast for videos The high contrast display was initially reserved for TV displays until they 2017 also appeared in PC monitors. However, the first tests of HDR monitors were sobering – differences between the display with and without HDR could not be recognized. The VESA specified the high-contrast reproduction on PC monitors only end 2017 in the DisplayHDR standard.

Enable the next step to increase the contrast Mini-LEDs, which were now evenly distributed on the display’s back instead of on the edge of the display and could be individually controlled Asus made the first device with countless tiny LEDs for full array local dimming (FALD) with his 32 – inch ProArt monitor with mini LEDs in front, beginning 2020 Apple followed suit in this country with the Pro Display XDR. The prices for these high-end monitors – they cost between 3000 and 6000 Euro – same as those in the middle of the 1990 years for the first LCD -Monitors had to put on the table.

Outlook: LEDs or OLEDs? Mini-LED backlights will eventually become mainstream in monitors. The alternative to this would be organic displays, but there will probably not be OLEDs in monitors for the foreseeable future – scaling to smaller diagonals works only very hesitantly, even in the TV sector.

Real LED displays, at where each pixel is realized with three light-emitting diodes, on the other hand, could first find its way into small, very special and therefore very expensive monitors. Until then, however, LCD technology will dominate the world of monitors for a long time.

This article comes from c’t 2020 / 24 .

(uk)