| 摘要 |
A laser marker/pointer for projecting circular or elliptical laser beam patterns onto a target surface such as a portion of a presentation screen or to assist in the aiming of a firearm, comprises a handheld shell body in which is mounted a laser light source, a rotating optical mirror driven by a motor, and an electronic drive circuit, whereby the aspect ratio of the marking pattern is determined by the geometric relationship of the motor shaft axis, the laser beam, and the mirror surface. The motor drive circuit when initially powered (along with the laser diode), applies full power (a continuous DC voltage to the motor to overcome inertia), followed by a pulsed voltage to lower the duty cycle of the motor, increase battery life, and reduce rotational noise. |
| 主权项 |
1. A laser beam marker for projecting a circular or elliptical pattern onto a receiving surface comprising:
a housing having a frontmost optical window; a laser beam generating device mounted in said housing; a mirror having a reflective front face, and a back face; an electric motor mounted in said housing, said motor including a rotatable shaft; said mirror having its back face attached to an end of said motor shaft, the front face of said mirror being receptive of a laser beam outputted from said laser beam generating device, whereby the angle of incidence between the first face of said mirror and the laser beam determines an elliptical or circular pattern of said laser beam reflected from said mirror through said optical window of said housing upon rotation of said mirror; a DC source of voltage mounted in said housing; a motor drive circuit mounted in said housing; a switch mounted in said housing, said switch being electrically connected between said voltage source, and said motor and laser beam generating device, said switch being selectively operable for simultaneously connecting said voltage source thereto, or disconnecting it therefrom; and said motor drive circuit being responsive to the operation of said switch to connect said voltage source thereto, for initially applying a constant level of DC voltage to said motor to overcome inertia for rotating said motor shaft for a first period of time followed by applying a pulsed DC voltage to said motor for a second period of time to reduce the duty cycle of said motor, until operation of said switch to turn off said device by disconnecting said voltage source from said motor and laser beam generating device. |
