An apparatus may include (1) a planar liquid-crystal structure including a plurality of liquid crystals, and (2) a plurality of electrodes coupled to the planar liquid-crystal structure such that (a) when a first plurality of voltages are applied to at least some of the plurality of electrodes, the plurality of liquid crystals are oriented such that the planar liquid-crystal structure operates as a diffraction grating having a first pitch, and (2) when a second plurality of voltages are applied to at least some of the plurality of electrodes, the plurality of liquid crystals are oriented such that the planar liquid-crystal structure operates as a diffraction grating having a second pitch different from the first pitch.

A projection device includes a drive housing that includes a protruding portion protruding from a central portion, a projection lens that includes a first rotation mechanism, and fans that draw in or discharge gas; the central portion includes a first A side surface that is provided in a first A direction X1 corresponding to one side in a first direction X and a second A side surface that is provided in a first B direction X2 corresponding to the other side in the first direction X; the protruding portion includes a first B side surface in the first A direction X1 and includes a second B side surface, which faces the projection lens, in the first B direction; and the fans face the second A side surface and the second B side surface.

A color wheel phase detection method and system, and a projection device. The phase detection system comprises a color wheel (1), a color wheel motor (2) that drives the color wheel (1) to rotate, and a control circuit (3); the color wheel motor (2) is a three-phase motor, and the control circuit (3) comprises a three-phase driving circuit (31) for driving the color wheel motor (2) to operate. The phase detection system further comprises a phase detection device (4) for detecting the three-phase driving circuit (31); when detecting a preset phase, the phase detection device (4) sends a pulse signal to the control circuit (3) to implement color wheel phase detection. Therefore, the effects of low costs, high accuracy, and high reliability are achieved.

A projector of the present invention includes a light source unit including a semiconductor light emitting element and a color wheel and emitting lights in first and second wavelength ranges in time division, a display device receiving light source light to form image light, a projection optical system for projecting the image light onto a projection target, a delay time setting module for shifting a start timing of a color mixing period when the lights in the first and second wavelength ranges are emitted in a mixed fashion in a spoke period of the color wheel during which emissions of the lights in the first and second wavelength ranges are switched over based on an index indicating a brightness of light from the light source unit, and a light source driving module for driving the light source unit based on a setting set by the delay time setting module.

An apparatus for high dynamic range (HDR) modulation includes one or more lasers configured to transmit respective beams of laser light with a single color mode and a PLM optically coupled to the one or more lasers. The PLM is configured to modulate the laser light to produce a first modulated light. The apparatus also includes a phosphor optically coupled to the PLM and configured to receive at least a first portion of the first modulated light from the PLM and to emit a phosphor light with multiple color modes. At least one spatial light modulator (SLM) is also optically coupled to the phosphor and configured to modulate the multiple color modes in the phosphor light and the single color mode to project a second modulated light.

An image projection apparatus includes: a light source; an image display element including multiple micromirrors arranged in two dimensions, the multiple micromirrors forming an image display plane, each micromirror having a reflecting surface; and a projection optical system. Conditional expressions (1) and (2) below are satisfied:
θ1≥14(deg)  (1)
1.2<BF/L<2.2  (2) where θ1 is a maximum tilt angle of the reflecting surface of each micromirror with respect to the image display plane, L is a diagonal length of the image display plane, and BF is a distance between a vertex of a lens within the projection optical system and closest to the image display plane and the image display plane along an optical axis of the projection optical system.

An optical processing turntable and a projection device are provided. The optical processing turntable has a first mass center and a height. The optical processing turntable includes a substrate and a driving component. The substrate has a second mass center. The driving component is disposed on the substrate to drive the substrate to rotate. The driving component has a locking surface. A distance between the locking surface and one of the first mass center and the second mass center relatively far from the locking surface is less than or equal to ⅔ of the height. The invention can effectively reduce the vibration and noise of the optical processing turntable during high-speed operation, and can increase the operating life of the optical processing turntable.

The disclosure provides a projection system and a gamma curve correction method. The projection system includes a projection target and a projection device. A test image is projected on the projection target. The projection device obtains a first gamma curve of the test image by receiving the test image projected on the projection target or sensing a light beam of the projected test image, and judges whether multiple difference values between the first gamma curve and a preset gamma curve is larger than a preset value. The first gamma curve is corrected to generate a second gamma curve when at least one of the difference values is larger than the preset value. The projection system and the gamma curve correction method of the disclosure provides an ideal gamma curve according to the output performance of the use situation.

An illumination device for a light modulated projector includes a first and a second colour wheel. A first filter surface of the first colour wheel comprises at least three first surface sections arranged one behind the other, which protrude into an illumination beam path of the illumination device successively on rotation and in each case convey illumination radiation of a different partial range of the visible wavelength range. At least one of the first surface sections of the first filter surface conveys illumination radiation from the infrared range. A second filter surface of the second colour wheel comprises a first surface segment which only conveys illumination radiation from the visible wavelength range and a second surface segment which only conveys illumination radiation from the infrared range. The first and second surface segments protrude into the illumination beam path successively on rotation.

Provided is the image display apparatus including: the light source which emits excitation light; a phosphor which converts the excitation light into fluorescent light and rotates; an image display element which modulates the fluorescent light; and a control unit which controls the image display element so that the image display element repeats first displaying based on an image signal and second displaying which is darker than the first displaying, at a predetermined frequency, wherein when a higher frequency of the predetermined frequency and a rotation frequency of the phosphor is represented by Fhigh, and a lower frequency thereof is represented by |Fhigh/2−Flow|<15.