Patent ID: 6030100
Filing Date: 2000-02-29
Classification: F21S,F21V,F21W,G02B

Abstract:
A control apparatus for a stepwise light projecting device which includes:a stepping motor with a casing having a top wall and front and rear lateral walls, a rotor mounted rotatably in the casing, and an output shaft coupled to and driven by the rotor, the output shaft having front and rear ends that respectively extend outwardly of the front and rear lateral walls,a shielding wheel mounted uprightly and coaxially on, and capable of rotating with the front end of the output shaft, the shielding wheel having a peripheral portion which is sized so as to extend above the top wall of the casing and which is formed with a plurality of through holes angularly spaced from one another by an interval, the shielding wheel being provided with a plurality of differently colored transparent sheets that cover the through holes respectively, anda light source disposed spacedly behind the shielding wheel, the light source being capable of being activated so as to emit a light beam that travels along a route above the top wall of the casing of the stepping motor and that passes successively through the colored transparent sheets when the shielding wheel rotates so as to illuminate an object in front of the shielding wheel with colored light rays, said control apparatus comprising:a photosensor adapted to be mounted on the rear lateral wall of the casing of the stepping motor, said photosensor including a phototransmitter and a photoreceiver spaced from said phototransmitter to define a channel therebetween;a slotted wheel adapted to be mounted detachably and uprightly on and adapted to rotate with the rear end of the output shaft, said slotted wheel having a circumferential portion which extends into said channel of said photosensor and which is formed with a radial slot to permit transmission of radiant energy from said phototransmitter to said photoreceiver only when the shielding wheel is in a predetermined starting position such that one of the colored transparent sheets is aligned with the light source; andcontrol circuit means connected electrically to said photosensor and adapted to be connected electrically to the stepping motor, said control circuit means being activable to operate in an initialization mode, in which said control circuit means is adapted to activate the stepping motor to rotate the shielding wheel stepwise by a first angular magnitude smaller than the interval between an adjacent pair of the through holes in the shielding wheel when said slotted wheel blocks transmission of the radiant energy from said phototransmitter to said photoreceiver until the shielding wheel is in the predetermined starting position, and in a regular mode after the initialization mode, in which said control circuit means is adapted to activate the stepping motor to rotate the shielding wheel stepwise by a second angular magnitude equal to the interval between the adjacent pair of the through holes in the shielding wheel in order to result in a predetermined stepwise light projecting effect when the light source is activated.