| 摘要 |
PURPOSE:To improve inspection efficiency by providing a sheet which varies color density when applied with a voltage in contact with a printed wiring board and knowing the position of a defective part with ease. CONSTITUTION:An electrochromic element sheet (ECD) 12 and an electrode are provided while sandwiched between a printed board 1 and a base 10. If a defective part is found by inspecting the printed wiring board 1, a voltage is applied between an inspection probe 3 and the electrode 13. Then, the ECD 12 colors with the voltage and varies in color density with the applied voltage, so the voltage is made different between a short-circuit defect and an open fault to vary the density of a color, thereby easily discriminating both faults Further, the voltage applied to the ECD 12 is about 1V or low and when the inspection voltage of the wiring board 1 is hither than it, the voltage is switched to a display voltage for the ECD 12. Further, the ECD 12 is applied with the voltage reversely and then discolored, so the ECD can be used repeatedly.
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