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Laser display

Design innovation for user displays in next-generation products is made possible by laser micromachining technology

What do Tesla, Bang & Olufsen and Apple have in common? Although the companies’ common bonds are probably greater in number than one might imagine, the standout commonality is the way the companies are able to marry cool, customer-centric design and state-of-the-art technology. 

While some customers make purchase decisions based on functionality and the price of that specific functionality, many consumers take a different approach. They immediately become passionate about a new product that takes functionality to the next level – one where the latest technology is incorporated into captivating design. 

While many drive a Prius, we all lust for a Tesla. After all, it’s tough to sacrifice being cool and looking good just to be fiscally responsible.

The problem

User displays in next-generation cars, airplanes, robotics, industrial equipment, electronics and consumer products are pushing engineering design limits. But today, intuitive, user-friendly controls are just the first step in good design. 

With the availability of the Internet of Things and with increased connectivity, the amount of data being pushed to the product user is increasing exponentially. With it, control panels are confusing, distracting and sometimes dangerous to the user operating the product. 

Therefore, consumers need displays that unobtrusively provide information without detracting from the user experience or the product’s functionality. In an ideal world, elements in a display that were not being used would become invisible when switched to the off state. This ideal world, however, isn’t necessarily a far-fetched reality.

The solution

New applications of laser micromachining technology are presenting an innovative solution to the problem of complex product displays through invisible hole backlighting applications. In this new type of display, elements are not visible to the naked eye when they’re not needed. When required, illumination from behind reveals a pattern of laser-drilled micro-holes that create the required configuration.

The images shown demonstrate how the invisible hole backlighting process works. The micro-holes are greatly exaggerated for demonstration purposes but are actually invisible to the naked eye. A light source is configured for providing light from behind the display and then transmitting the light through the holes when the pattern needs to be visible. The holes are conical shape and can penetrate through the thickness of the display material.

Invisible hole backlighting example with the backlight in “off” (left) and “on” (right) conditions.

Depending on the typical viewing distance, hole diameters on the front/user side need to be below the limit of resolution. Knowing that the limit of resolution for an adult human eye is around 0.1 mm at a distance of 1 m from the eyes, hole diameter ranges well below 50 microns are required to make the display patterns completely invisible without the backlight illumination.

The patterns formed by these invisible holes are large enough in illuminated condition to be observed by human eyes similar to the size of conventional status indicators. In addition, to present bright and sharp patterns, the micro-holes need to be closely spaced and allow higher light intensity to transmit within the unit area.

Potomac is able to produce holes measuring less than 20 microns in diameter and less than 50 microns in spacing in a variety of materials, including metals, opaque plastics and coated materials.

The process 

The process of producing these micro-holes was developed by Potomac Photonics Inc., a company that provides small- and micro-hole processing for its customers. Potomac’s services provide product designers with the capability to create the new displays that consumers need – and want.

The process is based on the company’s in-house capabilities for rapidly laser drilling thousands of closely spaced holes measuring less than 20 microns in diameter and less than 50 microns in spacing in a variety of materials, including metals, opaque plastics and coated materials with the most optimized surface finishes. For metal applications, Potomac can work with stainless steel, copper, nitinol, tantalum, gold and aluminum.

For the engineers at Potomac, the feature size to be processed as well as the type of metal and its reflectivity are the most critical factors in determining the optimal laser source to use. Once the laser source is determined, the laser beam is absorbed into the surface of the material where the energy of the laser is converted to heat to vaporize or melt the material. Additionally, a gas or fluid assist is leveraged to improve the cut quality, expel the molten metal and minimize the heat-affected zone.

From a quality and cost perspective, infrared lasers are typically employed. But, when features less than 10 microns are required, an ultraviolet laser is often a good alternative.

Engineers at Potomac have years of experience setting up jobs for processing intricate and complex features on flat and tubular metal substrates.

The next generation

Optimizing and modifying standard laser machine tools, Potomac developed the repeatable, accurate, high-precision micro-hole laser drilling techniques that make the backlit products work. The company’s experience with a range of materials laid the foundation for laser micromachining materials such as metals and polymers. The dimensions needed for invisible hole backlighting are not trivial, and Potomac has more than 30 years of expertise working on very small spatial scales.

Shown here, a Potomac engineer is setting up and running projects on the company’s laser systems to fabricate micro parts. 

Leading companies are integrating the new technology into next-generation products. As an example, Bang & Olufsen, which itself claims to be “synonymous with the art of acoustic perfection,” has filed patents for invisible hole backlighting for car stereos. And other high-tech companies are following suit, exploring the impact of invisible hole backlighting on their user experience.

Steve Jobs once said in a Fortune article, “We made the buttons on the screen look so good you’ll want to lick them.” Thanks to developments in laser micromachining, it looks like manufacturers will be making “lickable” display designs, too.

Potomac Photonics Inc.