- Collaboration and persistence drove the development of Dynabook LIFEBOOK WU5/J3
- Ultra-light laptop design combines innovation and cutting-edge IGZO technology
- COVID-19’s impact accelerated demand for lightweight, portable laptop designs
Innovation often requires persistence and a relentless pursuit of perfection, something which could possibly define the creation of the Dynabook LIFEBOOK WU5/J3, which weighs in at just 634 grams.
For Dynabook, this achievement wasn’t just about creating a lightweight device, it was about redefining what’s possible in mobile computing, the company has outlined in a new report.
From overcoming technical challenges to meeting the changing demands of a post-pandemic world, the story of the LIFEBOOK WU5/J3 shows the determination and ingenuity behind the world’s lightest 14-inch laptop.
Overcoming engineering challenges and COVID-induced urgent demand
The COVID-19 pandemic significantly impacted the mobile laptop market, driving demand for 14-inch screens due to the shift to remote work, with many larger laptop users transitioning to lighter, more portable devices. The value of “lightness” became more apparent as people moved their devices around the house during remote work.
However, despite the shift in demand, the notebook sections in retail stores were quiet during the pandemic, with fewer products available for in-store purchase, creating an immediate demand for lightweight notebooks
The UH-X/H1, which debuted in 2023, featured a 14-inch WUXGA (16:10) display and weighed in at 689 grams, slightly higher than the UH series record as a result of a compromise for a larger screen size.
Chief Manager Akinobu Kono described the challenges faced during the development of the 14-inch model as enormous. Despite aiming for 634 grams, the team encountered significant obstacles, with theoretical calculations indicating a limit of 666 grams – an unacceptable outcome for Kono, who associated the number with bad luck. When the 689-gram model debuted in January 2023, it was seen as a compromise and a blow to the series’ reputation.
To achieve the 634-gram goal, the team implemented three key innovations. A specially designed IGZO LCD display from Sharp, a laminated pouch-type battery, and a new magnesium-lithium alloy.
The advanced Sharp panel reduced the device’s weight by 23 grams using an ultra-thin glass and a custom-designed backlight, the new battery provided a 24% capacity increase while shaving off 12 grams, and the magnesium-lithium alloy introduced for the keyboard cover saved another 18 grams.
The company also introduced additional fine-tuning, such as redesigning the touchpad sub-board, shortening the heat pipe lengths and revising the protective sheets to meet its target. Together, these advancements accounted for 53 grams in weight savings.
The display contributed the most (40%) to the weight reduction, and was achieved through the custom design of the IGZO panel. Developed in collaboration with FCCL and incorporating newly developed glass, light guide plates, and lens sheets, the new glass is 15% thinner and lighter, marking Sharp’s thinnest panel for PCs.
However, compromising on thickness introduced new strength challenges, and the backlight was redesigned to combine the lens and diffusion sheets into one for added regidity.
During development, technical issues arose, such as uneven brightness caused by burrs during light guide plate processing and light leakage from the bottom edge, which were resolved through intensive troubleshooting by Sharp’s and Haruki Taguchi’s teams.
The final, fully operational IGZO display was only ready by late September 2024, just in time for the scheduled product announcement on October 5.
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