| 摘要 |
<p>PURPOSE:To improve the detection precison when whether an object of detection such as a form is present or not is detected, by shifting the optical axis of a light emitting element from the optical axis of a photodetecting element by about 1mm.. CONSTITUTION:The light emitting element 1 and photodetecting element 2 are arranged so that their optical axes 3 and 6 shift from each other by about 1mm.. The ratio of the intensity of photodetection when there is not the object 4 of detection between the light emitting element 1 and photodetecting element 2 and that when the object is present, i.e. S/N ratio is maximized at a position a little bit off the optical axis 3 of the light emitting element 1 sideward as shown in a figure. For example, the S/N ratio is about 2:1 conventionally when the optical axes of the light emitting element 1 and photodetecting element 2 are aligned to each other, but improved to about 3:1 when the optical axis 6 of the photodetecting element 2 is shifted from the optical axis 3 of the light emitting element 1 by about 1mm..</p> |
