Coherent develops borderless display cutting technology

Coherent utilizes deep ultraviolet laser technology to study and improve the cutting process of displays, but the production of such displays is still very complex.

Coherent, the host of the Mid-Europe Chapter Conference of the Society of Information Display (SID-MEC Conference) in Germany, has offered a look at its plans for improved display cutting. As a provider of laser solutions, the Göttingen-based company is not only specialized in annealing as a pre-stage in display production, but also develops tools for the subsequent cutting of displays.

Coherent utilizes lasers and aims to further optimize the process so displays without bezels can eventually be cut. In recent years, these display borders have become thinner as some manufacturers folded the display edges to at least give the appearance of a bezel-less screen. However, the material still breaks at the edge, which is then hidden by a bezel. This also helps protect the display, as these edges are where display layers can potentially start to separate.

Laser annealing as a preliminary step in display production (Image source: Coherent)

The image clearly shows how the cut of the glass looks from the side. With a UV laser at a wavelength of 355 nm, the result is visibly uneven. At the separation edge, the display layers are not cleanly divided and a frame around the display is necessary. With 345 nm, the result improves somewhat, but it is still not sufficient for a bezel-free display.

Cross-section from the side with the result of three different wavelengths (Image source: Andreas Sebayang/Notebookcheck)

This can be achieved with so-called deep-UV lasers, as shown in the third image. With a wavelength of 266 nm, the laser can separate the display so precisely that the layers at the edge are barely damaged. This results in a borderless display. The material loss at the boundary is expected to be less than one pixel. According to Coherent, there already is a gap of 50 to 60 micrometers between pixels, which is where the cut can be made. Of course, the cut edge still needs to be protected.

However, display production with deep UV lasers has some drawbacks. It is not yet ready for mass production. The available 10W lasers do not allow fast cutting of displays, which would make production too expensive. Coherent expects lasers with 20W, which should make mass production possible.

Coherent has not yet said when that will happen. In any case, the equipment will have to be shipped from Göttingen to the display manufacturers and integrated into their production lines.

Source: notebookcheck