Stunningly Bright Illumination Achieved Utilizing ROHM’s Original LED Technology


As a part of its social contribution activities, ROHM has implemented large-scale lighting displays in the areas around its headquarters in Kyoto. For the 20th year, with a theme of ‘A moment that captures the heart with dazzling brilliance,’ over 860,000 lamps were used to illuminate and warm the Kyoto winter nights for about a month, until December 25 (Tue).

This time, in addition to ROHM Illumination 2018, we will cover the actual LEDs used in the various lighting displays.


ROHM Illumination 2018 highlights

One of the main attractions of Illumination 2018 is the annual a capella concert performed by university students. A total of 47 teams from 11 universities in the Kansai area compete in the area’s largest a capella event that takes place on 94 stages (8 stages/day). For example, on the lawn plaza there is a fantastic stage where visitors can take time to enjoy the lighting that changes with the soothing voices of students.

The lighting show on the lawn plaza was also updated this year. The ‘Cocktail Light Garden’ features multiple 1m LED bars along with a large-scale 6m (h) x 12m (w) LED vision display installed on the lawn that emits light in a ripple-like effect, invoking a sense of dynamism that flows throughout the space. Viewers can enjoy a light show that responds to the music.

Other places of interest include illuminated Yamamomo (Bayberry) ‘symbol trees’ marking the beginning of the Promenade of Light that creates a wondrous light-filled atmosphere. When you come to Kyoto, feel free to take a stroll over to ROHM headquarters.


Creating dazzling light displays with ROHM LEDs

Of course, as a leading semiconductor supplier ROHM LEDs were used in the creation of the various Illumination light displays.

Ever since the company produced its first lamp LEDs in 1973, for over 45 years ROHM has been at the forefront of the industry. We talked with some engineers from the LED production division about ROHM’s LEDs which were essential in achieving the lighting effects during Illumination.

ROHM’s biggest strength is the ability to implement product development with thorough quality control utilizing a vertically integrated production system in which every process, from element fabrication to packaging, is carried out in-house. And our motto of ‘Quality First’ which is included in our company mission, has been incorporated into virtually every phase of LED production, such as by implementing an easy-to-manufacture chip design during the assembly process, introducing traceability for ultra-compact components, and carrying out process management of automotive-grade products. Placing more of an emphasis on production technology and quality control makes it possible to provide superior LEDs that meet customer needs for greater miniaturization and reliability.

The following are ROHM’s distinctive LEDs.
The first is decreased size and thickness. The increasing miniaturization of consumer appliances has in turn demanded smaller components. Proprietary production technology allows ROHM to not only decrease the size of the element itself, but also lower the gold wire connecting the board to the element as well, resulting in an unprecedented package height of just 0.2mm.

The next is stable brightness, achieved by minimizing variations. This makes our LEDs ideal for applications that place LEDs side-by-side, such as in automotive instrument panels and industrial equipment, since our integrated completely in-house manufacturing system from the element fabrication stage eliminates the need to adjust for uniform light intensity, reducing customer design load considerably.

Finally, extreme durability is also one of ROHM LEDs’ unique features. For applications exposed to harsh environments such as stop lamps in vehicles, ROHM has released the industry’s first sulfuration-resistant LEDs designed to prevent aged-based deterioration.

And ROHM continues to develop and introduce products in response to market demands, such as compact LEDs that prevent light leakage in automotive cluster panels.

Left: Vehicle Rear Lamp Demo Highlighting the Advantages of ROHM LEDs
Right: Broad Color Lineup Achieved Utilizing ROHM's Vertically Integrated Production System

It should be noted, however, that product development wasn’t always straightforward.
Although today it is commonly recognized that LEDs can provide stable brightness for many years, in the beginning engineers struggled to improve reliability, especially when used outdoors. A variety of phenomenon occurred when exposing LEDs to the elements that were not seen during indoor use, such as rapid degradation (within a year) in low temperature environments (i.e. during winter), high brightness red LED elements that darkened when exposed to moisture, and white LEDs that turned yellow. Nevertheless, by working as a team ROHM were able to overcome each issue and achieve a superior product.


Leveraging our industry-leading reliability

Today, LEDs have become an indispensable part of everyday life. LEDs are used in a wide variety of applications, from rear lamps, clusters, and ambient lighting in vehicles to industrial equipment such as numerical displays and indicator panels as well as function indicators in consumer devices, and demand is only expected to increase in the future.

“In recent years ‘reliability’ has become among the most important requirements, particularly in the automotive and industrial equipment sectors. At ROHM, ‘Quality First’ has been incorporated in our company mission, and we believe that ensuring reliability through our integrated production system gives us a considerable advantage over our competitors. In addition, it is extremely important that we provide comprehensive support to our customers. And going forward, we will continue to focus our resources on applications requiring LEDs that provide superior performance (i.e. reliability, design characteristics),” stated a ROHM engineer.

Among the many semiconductor technologies, LEDs are perhaps the most familiar. A wide range of everyday applications are supported by LED technology, including ROHM’s Illumination which continues to stun and delight onlookers during the winter nights. As a leading semiconductor manufacturer, ROHM will continue to contribute to society by developing breakthrough products and solutions that meet market needs.