Headband for diagnostic instruments comprising light source and accumulator module

A head band for diagnostic instruments comprising a light source and a battery has, at its back support part, a flat housing for adjusting and fixing the head band length by means of a rotary knob. An accumulator module optimized with regard to volume, weight and weight distribution can be mounted and detached by means of bayonet-type grooves at the housing and pins at the accumulator module, and can be fixed by means of a resilient spring at the housing and a recess in the accumulator module without impairing the function of the rotary knob.