Patent ID: 9397475
Filing Date: 2016-07-19
CPC Classification: H01S

Claim Text:
1. A method for adjusting a light emitting device having a light source that generates a relaxation oscillation immediately after an electric current is applied thereto for driving light emission; a capacitive reactance circuit that exhibits low impedance immediately after the electric current is applied thereto and which is chargeable with electrical charge; a resistance circuit that discharges electrical charge charged in the capacitive reactance circuit after a predetermined time passes after the electric current is applied; a differentiation circuit formed of the capacitive reactance circuit and the resistance circuit, which are connected in parallel; and a switching element, wherein the light source and the differentiation circuit are connected in series; and the switching element is configured to switch on or off for application of voltage to the light source and the differentiation circuit, the method comprising: adjusting at least one of capacitance value and impedance of the capacitive reactance circuit so that electric current flows in the light source at not less than a threshold current value for oscillation while an initial oscillation of the relaxation oscillation is generated immediately after the electric current is supplied to the capacitive reactance circuit, and so that the electric current flows in the light source at an amount at which the light emission of the light source does not come to be an oscillation stationary state; and adjusting resistance value of the resistance circuit to be not less than a value at which electric current approximately equal to the threshold current value for oscillation of the light source flows and at which the light source does not emit light, and not more than a value, at which a difference between voltage dropped at the resistance circuit and a power-supply voltage is approximately equal to a forward direction voltage of the light source, such that light of only the initial oscillation of the relaxation oscillation is emitted.