| Summary: | 博士 === 國立清華大學 === 工業工程與工程管理學系 === 89 === Along with the dramatically expanding use of visual display terminals (VDTs), associated health problems, predominately visual and musculoskeletal discomforts, have become subjects of growing concerns. Among those attributed risk factors, VDT workstation preferred settings and work-related psychosocial factors are two of the most concerned ones.
Many studies have shown that the physical discomforts were reduced with preferred settings. Therefore, incorporating the considerations of anthropometrics and individual preferred settings while designing VDT workstation has been embraced as a primary measure for preventing the above problems. However, almost no VDT workstation preferred settings data for Taiwanese works has been ever reported. As for the work-related psychological factors, the etiologic mechanisms of their effects on health problem are still poorly understood. However, much evidence has suggested a larger role for workplace psychosocial factors in producing adverse health effects than was previously though to be the case.
This study was conducted in a semiconductor manufacturing company in Hsinchu, Taiwan. The purpose of this study was to investigate the preferred settings of VDT works. The effects of ergonomics training on preferred settings and the deviations of field workstation from preferred settings would also be assessed. Besides, the contribution of several alleged psychosocial risk factors (e.g., lack of social support, monotonous work, lack of job control, and intensified workload) on physical discomforts and their interactions with physical/ergonomic variables would be evaluated. After assessment, countermeasures to reduce VDT physical discomforts were proposed. Some of these are going to be employed and evaluated in the company.
Regarding the preferred settings of VDT workstation, results showed that the main differences on preferred settings between PC and CAD workstation were head-neck posture and gaze angle that were mainly caused by the difference in monitor size. Since neither the desk height and the monitor stand height, nor the seat height showed significant difference between the two types of workstations, similar adjustable dimensions may be specified for the design of both workstations. Except that the CAD workstation should allow for greater monitor screen to desk edge distance. In addition, comparing the preferred settings with previous reports based on western data, a consistently and significantly lower preferred monitor height, keyboard height and seat height were observed for the Taiwanese VDT users. As for the effects of ergonomics trainings on preferred settings, results showed that all subjects took a same adjustment strategy on the fully adjustable VDT workstation. They set the monitor height right after the setting of seat height and desk height. Besides, the lecture-based ergonomics training was found helpful because not all of the subjects were aware of the advantages of using posture supports and document holder before the training.
As for the effects of deviation from preferred settings on physical discomforts, results showed that deviations in eye to monitor distance, in elbow height-keyboard height difference and in trunk inclination angle were the most predictive variables on physical discomforts. Finally, regarding the relationships between psychosocial factors and physical discomforts, results showed that physical/ergonomics variables were found more dominant than psychosocial factors for the visual and upper extremity discomforts; but for the back and lower extremity discomforts, psychosocial variables were the leading factors.
This research is a comprehensive and systematic investigation of the associated factors in the physical discomforts problems of the VDT users. The result can serve as reference for VDT workstation designer and so be beneficial to Taiwanese VDT users.
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