摘要 |
Two light flux areas are disposed in a direction along which a pair of vertically opposite angles defined by first and second straight lines are aligned, and the other two light flux areas are disposed in a direction along which the other pair of vertically opposite angles are aligned. A spectral element sets propagating directions of divided elements of each of light fluxes obtained by dividing each of the light fluxes by a third straight line intersecting with the first and second straight lines by an angle of 45 degrees, or by a fourth straight line orthogonal to the third straight line to disperse the divided elements on a photodetector. The photodetector is provided with sensors which individually receive the divided elements of the light fluxes. |