Adhesive bonding in an entirely new light

Technologies

The inner workings of smartphones, tablets and smartwatches are held together by numerous tiny adhesive tapes. Many manufacturers rely on high-performance tapes from tesa for that purpose. Now tesa is taking a technological leap with a new innovation: an adhesive tape that is activated by light.

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Electronics

They fix screens and displays, seal joints and absorb shocks, dissipate heat, bond components to the interior and exterior of devices or hold batteries and rechargeables firmly in place: Adhesive tapes are indispensable in electronic devices. Many manufacturers and suppliers rely on product solutions from tesa. For example, a smartphone contains up to 70 adhesive tapes, most of them double-sided – the smallest of them is just five micrometers (μm) thick, or 20-times finer than a human hair. The fact that the spirit of innovation knows no timeout at tesa is demonstrated by the latest product in the portfolio: the tesa® L-tape 869x.

Holds like it’s bolted on

Dr. Michael Egger, Laboratory Manager in the Electronics division at tesa in Norderstedt, was involved 24/7 in the research and development surrounding the new L-tape. The best part is: “It is a translucent adhesive tape, which is activated by UV light and then achieves its full strength. That makes it the perfect alternative to the standard pressure-sensitive adhesive tapes or liquid adhesives.” According to the experts, these can lead to long hardening times, in some cases leaving messy bonding surfaces. Which means that the L-tape based on a reactive acrylic adhesive is especially suitable for the permanent structural bonding of very small components in smartphones, smartwatches etc., comparable with the bolting together of components. The L-tape can also be applied at room temperature. For that reason too it is a welcome alternative to what are known as heat-activated films (HAF), which only achieve the required adhesive strength at 120°C.

We are delighted to have created another all-rounder with genuine added value, the new L-tape.

Carsten Meyer-Rackwitz

Head of Electronics

An all-rounder with added value

As in the case of many innovative products in the past, the L-tape is a result of close cooperation between tesa and its customers – a carefully tailored and yet flexible adhesive solution, as Carsten Meyer-Rackwitz, Head of Electronics at tesa, emphasizes: “We are delighted to have created another all-rounder with genuine added value, the new L-tape. It not only securely bonds the smallest parts and components, but can also be used for many different materials. It is shock-resistant and retains its strength even when exposed to moisture or heat.“

Design freedom for manufacturers

In addition to its speed and efficiency in use, the tesa® L-tape 869x could well offer another attractive benefit for the fast-moving electronics industry, as Product Manager Lukas Gross explains: “It combines a lasting adhesive bond with the greatest possible design freedom. The L-tape can be precisely adapted in size and shape to the needs of the manufacturer.” For example, as a small, ring-shaped piece of adhesive tape, only 0.1 millimeters thick, for sticking a camera lens into a smartphone. And even if fewer metal components and more plastic ones are used inside devices of the future, the new adhesive tape could well provide a reliable sense of cohesion in many a “lucid moment”.

With the tesa® L-tape processes can be simplifyed thanks to high initial tack and immediate bonding strength and light activation.

Exploded view of a smartphone showing its internal components. Layers include the display, circuit board, camera module, and outer casing. The components are highlighted with a faint blue glow against a dark background.

More about tesa L-tape

tesa® L-tape combines the advantages of simple and convenient processability of a PSA tape – such as preparation of adhesive geometries down to the smallest dimensions, tackiness at ambient conditions, and high thermal stability – with the advantages of increased bonding performance known from structural bonding tapes or liquid adhesives.

Last updated on 15 Apr 2026