Effects of Lighting Environment on Visual Sensitivity, Cognition Memory Performance, Fatigue and Comfort in Lithography Area

隨著半導體與LED產業的發展，採用黃光照明的廠區日益增多，暴露於黃光的作業人員也越來越多。在黃光區作業主要是進行光罩微影製程，為了保護光阻材質，環境中凡波長低於500 nm的光波都必須被阻絕。所以光罩微影製程區的照明設備通常採用黃色光源，以致人眼不易辨別物體真實的顏色，並可能衍生出對於視覺表現的影響。 為了解黃光區作業環境光源的特性以及作業人員的光暴露實態，並釐清作業環境光源與作業人員視覺表現之間的關連性，本研究在一家固態照明產品製造公司工作現場進行實地研究。針對12名黃光區作業人員(暴露組)與12名鄰近之白光區的作業人員(對照組)作視覺表現測驗。作業環境照明光源係使用光譜儀量測光照度、相對色溫與演色性等；而作業人員則進行視覺敏銳度、視覺認知記憶力的測驗與視覺疲勞舒適度的評估。 研究結果顯示，黃光區的環境照明光源主要為500 nm以上波長的光波，其平均光照度為292 lux與相對色溫平均為2223 K，相較於白光區的環境照明的光照度與相對色溫均低許多。黃光區與白光區作業人員的色棋測驗平均錯誤分數分別為91.5與26.8分，達到統計上顯著差異(p<0.0001)。此外，所有的視覺敏銳度與視覺認知記憶力測驗結果均顯示黃光區作業人員的視覺表現較白光區作業人員差。而且黃光區作業人員自覺的視覺疲勞程度較高，也比較認為其環境照明的舒適度不佳。故本研究建議提高黃光區環境照明光源之光照度，並定期將黃光區作業人員輪調至其他作業區。 本研究在不干擾生產線工作的原則下，以作業人員實際的工作環境進行實地研究。雖然本研究中黃光區與白光作業人員在視覺表現上的差異暫無法歸因於特定一項光學參數，但其暴露於特殊黃色光源的總時間，已經比一般實驗室研究的模擬暴露時間更長久，有助於觀察長時間暴露於特殊黃色光源下對於視覺表現的影響狀況。藉由本研究成果，希望能促使工業界對黃光區環境照明光源與作業人員作適當的實務管理，並能依此研究成果進行必要的工作區輪調，更進一步保障職場作業人員的健康權益。In the past decades, the semiconductor and the light emitting diode (LED) industries grew rapidly in Taiwan and the number of fab with lithography area kept increasing. Thus, workers exposed to yellow light at work increased as well. In order to protect photo resistor, light of wavelength less than 500 nm would be blocked using yellow fluorescent lightening, which might modify workers’ perception of color as well as visual performance. This study aimed to characterize on-site lighting environment in both lithography area and its adjacent area, and assess the workers’ exposure to the particular lighting at work in a wafer fab. To clarify the possible association between lighting environment and visual performance of workers, this study was carried out in the lithography area and its adjacent area of a LED fab for comparison. There were 24 workers recruited in this study, half of them working in lithography area (exposed group), and the others working in the adjacent area (control group). Spectrometer was applied to measure the lighting condition in both areas. Visual sensitivity test, cognition memory performance test, fatigue and comfort assessment were applied to assess the workers’ visual performance. Results of lighting measurement at work places demonstrated that not only light with wavelength less than 500 nm were blocked in lithography area, but also the illumination (292 lux) and correlated color temperature (2223 K) in this working area were much lower as compared to its adjacent area. Moreover, all the visual tests’ results showed poorer visual performance for workers in lithography area as compared to those workers in the adjacent area. The error scores of color perception test were 91.5 points and 26.8 points for exposed group and control group, respectively (p<0.0001). Besides, the workers in lithography area were prone to get visual fatigue and feel uncomfortable under yellow lighting. Results of this study suggested that the illumination of lithography area might need to be increased and the workers in lithography area might need to be routinely rotated in order to prevent adverse effect on visual performance. However, difference in visual performance between study groups was hard to be attributed to any lighting related parameter since none of them could be manipulated in this field study for research purpose. In future, a long-term follow-up study with larger sample size is warranted to clarify possible adverse effects resulting from working in lithography area by controlling confounding factors. It’s expected that our findings would urge the industry to improve and practice suitable management in lithography area for working environment and condition. In addition, these findings could be used as reference for the working area rotation plan