| 摘要 |
PURPOSE:To lessen entering of dust and foreign matter while keeping the distance between a sensor for the quantity of charge and sample constant, by forming a recess part in the substrate surface of a body of revolution and by providing the sensor between this recess part and a charge holding layer formed on the substrate surface. CONSTITUTION:Charge holding layer 1 is made of a photosensitive material, for example, and sensor 6 for the quantity of charge is composed of substrate 2 of a body of revolution made of Al, etc., and source 3, drain 4 and gate 5 of respective FETs. The sensor is buried in substrate 2. Then VDD lead-out line 9 connected to drain 4 of sensor 6 is provided making a round inside of body 7 of revolution and wired so that lead line 10 provided to fixed shaft 8 will rub against the VDD lead- out line 9. This constitution holds constant the distance between the sensor and charge holding layer regardless of the eccentricity of the drum because the sensor is buried. In addition, the charge holding layer protects the sensor surface, so that the entering of dust, foreign matter, etc., is lessened. |
