The ornamental design for an integratingsphere for lightflux meter, as shown and described.
FIG. 1 is a perspective view of an integrating sphere for light flux meter showing my new design;
FIG. 2 is a front view thereof showing a sphere being mounted concentrically on top of a cylindrical base;
FIG. 3 is a rear view thereof showing an annular flange being formed circumferentially around the sphere;
FIG. 4 is a left view thereof;
FIG. 5 is a right view thereof;
FIG. 6 is a top view thereof showing a disk with a light source inlet being formed through the top of the sphere and aligning concentrically with the base;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is another left view thereof with a light flux meter shown in broken lines.
The portions of the Figures shown in broken lines are shown for illustrative purposes only and form no part of the claimed design.