Effects of the liquid crystal display tilt angle of a notebook computer on posture, muscle activities and somatic complaints

Abstract More con strained posture and higher neck muscle activities have been reported among users of notebook computers than those of desktop computers. Complaints of eye and musculoskeletal d iscomfort as well as di fficulty of keying were greater during work with notebook computers. These reports ascribed the findings to the differences in the size of desktops and notebooks. Another ergonomic aspect of the notebook computer distinct from the CRT is its angle-dependent luminance contrast. The present study investigated the effects of liquid crystal display (LCD) tilt angle of a notebook computer on posture, muscle activities and somatic complaints in 10 subjects. At the tilt angle of 100°, the subjects were noted to have relatively less neck flexion. The static neck extensor muscle activity was also lowest at this tilt angle. Nonetheless, the complaint survey revealed higher rates of discomfort while viewing and using the LCD set at the tilt angle of 100°. The findings of this study strongly suggested that the ergonomic features and problems attributable to notebook computers are distinct from the desktop computers. The points of interest raised in this paper should be considered when contemplating the use of notebook computers. Relevance to industry The use of notebook computers has increased steadily over the last 5 years , especially in Japan. Few authors have ventured to study the problems associated with these smaller computers . The results and suggestions of this stu dy may contribute to improve the design of notebook computers and the workstations .