| 摘要 |
PURPOSE:To evaluate whether or not sufficient visibility is obtained in visual environment when a device is viewed by calculating the permissible quantity of display surface illuminance with which the visibility of characters displayed on the device is larger than a certain value. CONSTITUTION:A measurement part 1 for the brightness of a light emission part and a measurement part 2 for the brightness of a background part, an equivalent light curtain measurement part 3, a brightness coefficient input part 4, a visibility input part 5, a permissible illuminance arithmetic part 6, a display surface illuminance measurement part 7, an illuminance comparison part 8, etc., are provided. Then, an arithmetic part 6 calculates permissible illuminance necessary on a surface for obtaining visibility with contents displayed on the device can be viewed without any error by using signals from the measurement parts 1-3 and signals from the input parts 4 and 5. Then, the comparison part 8 inputs a signal corresponding to the permissible illuminance calculated by the arithmetic part 6 and a signal corresponding to the display surface illuminance from the measurement part 7 and compares those values with each other to output a signal corresponding to the comparison result. Thus, whether or not the visibility enough to see the device is obtained in visual environment is evaluated.
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