US 11,906,890 B2
Laser projection apparatus
Xu Chen, Shandong (CN); and Jichen Xiao, Shandong (CN)
Assigned to HISENSE LASER DISPLAY CO., LTD, Qingdao (CN)
Filed by HISENSE LASER DISPLAY CO., LTD, Shandong (CN)
Filed on May 4, 2023, as Appl. No. 18/143,398.
Application 18/143,398 is a continuation of application No. 17/380,335, filed on Jul. 20, 2021, granted, now 11,669,005.
Application 17/380,335 is a continuation in part of application No. PCT/CN2020/137412, filed on Dec. 17, 2020.
Claims priority of application No. 201911315032.X (CN), filed on Dec. 19, 2019; and application No. 201911315259.4 (CN), filed on Dec. 19, 2019.
Prior Publication US 2023/0273514 A1, Aug. 31, 2023
Int. Cl. G03B 21/20 (2006.01); G02B 26/02 (2006.01); G03B 21/16 (2006.01); H02P 27/08 (2006.01)
CPC G03B 21/208 (2013.01) [G02B 26/02 (2013.01); G03B 21/16 (2013.01); G03B 21/2013 (2013.01); G03B 21/2033 (2013.01); H02P 27/08 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A laser projection apparatus, comprising a laser light source, a light combining mirror group, an optical path shaping lens, a diffusion wheel, a light collecting device, a light valve, a projection lens, a main control circuit, a diffusion wheel driving circuit and a temperature sensor, wherein
the laser light source is configured to emit laser beams of three colors;
the combining mirror group is configured to combine the laser beams of three colors;
the optical path shaping lens is configured to shape a light path of the combined laser beams; and the combined laser beams are transmitted to the optical path shaping lens and then incident to the diffusion wheel;
the diffusion wheel is configured to homogenize the laser beams and then transmit the laser beams to the light collecting device;
the light valve is configured to modulate light of each color into an image light beam and transmit the image light beam to the projection lens;
the projection lens is configured to project the image light beam onto a projection screen;
the diffusion wheel includes a motor and a diffusion portion, wherein the motor is a three-phase motor;
the temperature sensor is electrically connected to the main control circuit, and configured to detect an ambient temperature;
the main control circuit is configured to: determine a target starting current according to the ambient temperature; determine a duty cycle of a second startup pulse width modulation signal according to the target starting current, and provide the second startup pulse width modulation signal to the diffusion wheel driving circuit; and output an operating pulse width modulation signal to the diffusion wheel driving circuit when the diffusion wheel reaches a target rotation speed, wherein the target starting current is a minimum drive current required to drive the motor from standstill to starting to rotate, and the target rotation speed is a preset speed at which the diffusion wheel operates normally and speckles can be eliminated; and
the diffusion wheel driving circuit is configured to drive the three-phase motor to drive the diffusion portion in response to each of the second startup pulse width modulation signal and the operating pulse width modulation signal.