Upon the payment of a lump sum, the employer shall present to the appeals board a proper receipt evidencing the same, executed either by the injured employee or his dependents, or by the trustee. The appeals board shall thereupon issue its certificate in proper form evidencing such payment. Such certificate, upon filing with the clerk of the superior court in which any judgment upon an award has been entered, operates as a satisfaction of the award and fully discharges the employer from any further liability on account thereof.