Introduction Electronic assembly manufacturing has a working process which includes machine operation, assembly and fine work inspection of products with a microscope.

Objectives This study aimed to assess lighting intensity at workstations compared to the standards and the incidence of shoulder pain among electronic assembly workers.

Methods There were 167 electronic workers in one site of electronic manufacturing. The measurement of lighting intensity was performed with a lux meter at four types of job function, i.e. machine operation, assembly of parts, and two inspection types of moderate fine work and very fine products. The quarterly incidence of shoulder pain was calculated from monthly follow-up.

Results Insufficient lighting intensity was found in the highest proportion at the microscope station of lighting intensity zone 1 (eye-focusing zone) at >2,000–5,000

lux (81.12%), followed by the inspection with a monitor/profile projector (64.29%), and lighting intensity zone 1 at <1,000 lux (57.89%). The insufficient light was mostly identified within an arm’s length of the worker (zone 2) and outside an arm’s length (zone 3). The three-month incidence of shoulder pain was 85.3% and it was found that all workers had experienced shoulder pain at the four-month follow-up.

Conclusion This lighting intensity measurement method is suitable for identifying problems of the working environment of inspection stations, which is useful for further implementation. The high incidence of shoulder pain suggests that electronic assembly workers should be aware of the need to take frequently short breaks from eye-focusing work and stretch muscles for prevention of eye fatigue and shoulder pain.