Abstract: An illumination system and a projection device are provided. The illumination system includes at least one laser light source providing at least one laser beam and a polarizing rotation module including a first axle, a first driving element, and a polarizing element. The first axle has a first revolution frequency. The polarizing element is disposed on a transmission path of the laser beam. The first driving element causes the polarizing element to rotate in a temporally sequenced manner. When the polarizing element is rotated, the laser beam is transmitted to the polarizing element at a specific frequency in a plurality of first time periods. The laser beam passing through the polarizing element has different polarizing states at different times. The specific frequency and the first revolution frequency of the first axle are not exactly divisible by each other. The invention can generate an image with uniform polarizing direction.

Abstract: An optical wavelength conversion module including a substrate, a driving device, and a first phosphor material layer is provided. The first phosphor material layer is disposed on a first optical region of the substrate. A conversion beam generated by the first phosphor material layer is a yellowish green beam when a phosphor temperature of the first phosphor material layer is close to or equal to an ambient temperature. The conversion beam generated by the first phosphor material layer is a yellow beam when the phosphor temperature of the first phosphor material layer is close to or exceeds a preset temperature. The driving device is connected to the substrate. The driving device is adapted to drive the substrate to act when the optical wavelength conversion module is in an operating state, so that the yellow beam is emitted from the first optical region. An illumination module is also provided.

Abstract: A head-mounted display including a transparent display, a main liquid crystal lens and a first liquid crystal lens is provided. The transparent display is configured to emit an image light beam. The main liquid crystal lens is disposed near the transparent display. The transparent display is disposed between the main liquid crystal lens and the first liquid crystal lens. The first liquid crystal lens is configured to receive an ambient light beam. The head-mounted display allows at least a part of the image light beam emitted from the transparent display passing through a pupil by phase modulating of at least a part of the main liquid crystal lens.

Abstract: A wavelength conversion module, a forming method of a wavelength conversion module, and a projection device are provided. The wavelength conversion module includes a substrate and a plurality of wavelength conversion units. The wavelength conversion units are located on the substrate, wherein the wavelength conversion units include a first wavelength conversion unit and a second wavelength conversion unit, the first wavelength conversion unit includes a first wavelength conversion material and a first doping material, the second wavelength conversion unit includes a second wavelength conversion material and a second doping material, the first wavelength conversion material and the second wavelength conversion material are different from each other, and the first doping material and the second doping material are different from each other. By the wavelength conversion units comprising different doping materials, low cost, good heat resistance and efficient light emitting are achieved.

Abstract: A composite phase conversion element and a projection apparatus are provided. The composite phase conversion element is disposed on a transmission path of at least one beam, and includes at least one polarizing element, and the polarizing element includes multiple polarizing regions, where at least two of the polarizing regions have different polarization directions, the at least one beam simultaneously penetrates through at least two of the polarizing regions of the at least one polarizing element to respectively form at least two sub-beams, and polarization states of the two sub-beams correspond to the polarization directions of the at least two of the polarizing regions penetrated by the at least two sub-beams. Therefore, in a polarized 3D mode of the projection apparatus using the composite phase conversion element, color and brightness of a display image are uniform, and a user observes a 3D display image with good uniformity.

Abstract: A wavelength-converting device has a light incident side. The wavelength-converting device includes an inner annular portion and an annular portion. The annular portion is connected to an outer edge of the inner annular portion. The annular portion includes a wavelength-converting portion, a first heat-conductive bonding medium, a reflective layer, and a wavelength-converting layer. A groove is annularly disposed in the wavelength-converting portion, and the groove is recessed from the light incident side of the wavelength-converting device. The first heat-conductive bonding medium is disposed in the groove. The reflective layer is disposed on the first heat-conductive bonding medium. The wavelength-converting layer is disposed on the reflective layer and has a light receiving surface. A projection apparatus is also provided.

Abstract: A wavelength conversion module, a method of forming the same and a projection apparatus are provided. The wavelength conversion module includes a substrate and a wavelength conversion layer. The substrate has a rough surface including two first regions and a second region located between the two first regions in a radial direction on the substrate. The wavelength conversion layer is located on the substrate and includes a wavelength conversion material, a bonding material and diffuse reflection particles. The wavelength conversion material is distributed in the bonding material. The diffuse reflection particles are located on the rough surface of the substrate and between the wavelength conversion material and the substrate. A second density of the diffuse reflection particles in the second region is greater than a first density of the same in one of the two first regions.

Abstract: A projection device and a light engine module thereof are provided. The light engine module includes a first dichroic element, a first light valve, a second light valve, a light combining element, a first light converging element, a second light converging element, a first light guiding element, and a second light guiding element. The first dichroic element divides an illumination beam into a first color beam and a second color beam. The first light valve converts the first color beam into a first image beam. The second light valve converts the second color beam into a second image beam. The light combining element is disposed on transmission paths of the first image beam and the second image beam. The first light guiding element guides the first color beam to the first light valve.

Abstract: A head-mounted display including an apparatus body including a first part and a second part connected to the first part and an image display device disposed in the apparatus body is provided. The image display device projects an image to a projection target and includes an image output element, a plurality of lens elements, a light diffuser, and an imaging element. The imaging element projects the image beam to the projection target to display the image. The lens elements include a first lens element and a second lens element. The image output element generates an intermediate image on a transmitting path of the image beam between the first and second lens elements. The light diffuser is disposed on the transmitting path of the image beam and in a predetermined interval where the intermediate image is located at the center.

Abstract: A projection screen includes a substrate, a plurality of prism structures, and a plurality of light absorbing structures. The substrate includes a first surface adjacent to the projector and a second surface away from the projector. The prism structures are disposed on the first surface, and each of the prism structures includes a first inclined surface, a second inclined surface, and a bottom surface. The first inclined surface is configured to receive and reflect projection light beams. There is a first angle between the first inclined surface and the bottom surface, and a second angle between the second inclined surface and the bottom surface. The first angle is less than or equal to the second angle. The light absorbing structures are respectively disposed on at least a portion of the second inclined surface of each of the prism structures. The light absorbing structures are configured to absorb ambient light.

Abstract: A wavelength conversion module including a substrate and a wavelength conversion layer is provided. The substrate includes an axis, and the axis is located at the center of the substrate. The wavelength conversion layer is located on the substrate and includes two first wavelength conversion layers and a second wavelength conversion layer. Each of the first wavelength conversion layers includes a wavelength conversion material and a first bonding material. The second wavelength conversion layer is located between the two first wavelength conversion layers in a radial direction from the axis of the substrate to an edge of the substrate, and the second wavelength conversion layer includes the wavelength conversion material and a second bonding material. The first bonding material is different from the second bonding material. Moreover, a projection device and a forming method of the wavelength conversion module are also provided.

Abstract: A head-mounted display apparatus including a main body, a mask, and a projection apparatus is provided. The mask is pivotally connected to the main body. The mask includes a reflection area. The reflection area has a first normal line. The projection apparatus is disposed inside the main body and adapted to project an image beam to a target. The projection apparatus includes a mirror. The mirror has a second normal line. An acute angle exists between normal projections of the first normal line and the second normal line on a reference plane.

Abstract: A polarizing rotation device including a rotation shaft, a driving element and a polarizing element is provided. The driving element is configured to drive the rotation shaft to rotate. The polarizing element is connected to the rotation shaft and is disposed on a transmission path of at least one beam, where the driving element is configured to drive the polarizing element to rotate sequentially while taking the rotation shaft as a rotation central axis, and when the polarizing element is rotated, the at least one beam penetrates through the polarizing element, and the at least one beam penetrating through the polarizing element has different polarization states at different time. Therefore, when a projection device is in a polarized stereoscopic mode, a color or brightness of a display image is uniform, and a user observes a 3D display image with good uniformity.

Abstract: A wavelength-converting wheel, for converting an excitation beam having an output power greater than or equal to 100 W into a conversion beam, is provided. The wavelength-converting wheel includes a turntable having an annular irradiation portion, an adhesive layer disposed at the annular irradiation portion, a reflective layer disposed on the adhesive layer, and a wavelength-converting layer. The wavelength-converting layer is disposed on the reflective layer and has a light receiving surface configured to be irradiated by the excitation beam. The invention further provides an illumination system including the wavelength-converting wheel, and a projection apparatus including the illumination system. The heat dissipating ability of the wavelength-converting wheel is improved. The material of the wavelength-converting layer is not deteriorated or damaged due to the heat of the excitation beam.

Abstract: A projector and a wavelength-converting element are disclosed. The projector includes an illumination system, a light valve and a lens. The illumination system includes a light source providing an excitation beam, and a wavelength conversion device located at a transmission path of the excitation beam. The wavelength-converting element includes a substrate having a wavelength-converting area, an optical film disposed in the wavelength-converting area of the substrate, and a fluorescent film covering the optical film and converts the excitation beam into a converting beam. The converting beam and the excitation beam constitute an illumination beam. The fluorescent film contains phosphors, wherein the phosphors having a larger particle size are distributed among or above the phosphors having a smaller particle size. The light valve converts the illumination beam into an image beam. The image beam becomes a projection beam after passing through the lens.

Abstract: A phosphor wheel and a projection apparatus with the phosphor wheel are disclosed. A phosphor wheel includes a driving motor, a temperature interference element, a substrate and at least one light wavelength converting layer. The driving motor includes a motor body and a rotating member. The motor body drives the rotating member to rotate relative to the motor body along a rotation axis. The temperature interference element is connected with the rotating member and the substrate. The motor body drives the rotating member to rotate the temperature interference element and the substrate relative to the motor body. The substrate includes a first surface and a second surface disposed opposite to each other. The second surface is located between the first surface and the rotating member. The light wavelength converting layer is disposed on the first surface of the substrate.

Abstract: A wavelength conversion element, a forming method of the wavelength conversion element, a wavelength conversion module and a projection device are provided. The wavelength conversion element includes a wavelength conversion material, a binder, a filling material and a plurality of cavities. The wavelength conversion material is dispersed in the binder to form a wavelength conversion layer. The filling material is located in the wavelength conversion layer. The cavities are located in the wavelength conversion layer, wherein the filling material fills some of the cavities. The wavelength conversion module includes a substrate and the above wavelength conversion element. The projection device includes the above wavelength conversion module, an excitation light source, a light valve and a projection lens. The disclosure enables the projection device to have good conversion efficiency and reliability.

Abstract: A projection device for forming an image frame on a projection screen includes a first illumination system for emitting an illumination beam, a second illumination system for emitting an ultraviolet beam, a first light valve located on a transmission path of the illumination beam and for converting the illumination beam into a visible image beam, a lens located on a transmission path of the visible image beam and the ultraviolet beam and for projecting the visible image beam onto the projection screen to form an image frame area and projecting the ultraviolet beam onto the projection screen to form an opaque area, and a processor electrically connected to the first illumination system and the second illumination system and for controlling the first illumination system to emit the illumination beam and controlling the second illumination system to emit the ultraviolet beam. The image frame area partially overlaps the opaque area.

Abstract: A projection screen for receiving a visible image beam and an ultraviolet beam from a projection device is provided. The projection screen includes a substrate, an anti-reflection layer and an anti-ultraviolet layer. The substrate includes a first surface adjacent to the projection device, a second surface away from the projection device and opposite to the first surface, a scattering reflection layer disposed between the first surface and the second surface, and an ultraviolet absorption layer disposed between the first surface and the second surface. The scattering reflection layer scatters and reflects the visible image beam. The ultraviolet absorption layer absorbs the ultraviolet beam so as to be changed from a transparent state to an opaque state. The anti-reflection layer is disposed on the first surface. The anti-ultraviolet layer is disposed at the second surface. The ultraviolet absorption layer is located between the scattering reflection layer and the anti-ultraviolet layer.

Abstract: A rear projection screen includes a prism film, a first diffusion layer, a second diffusion layer and a light absorbing film sequentially disposed along a first direction. The prism film includes a first light-transmitting substrate and prism structures, wherein the prism structures are disposed on a surface of the first light-transmitting substrate away from the first diffusion layer. The prism structures receive an image beam and guide the image beam to be transmitted along the first direction. The first diffusion layer and the second diffusion layer have different refractive indexes. There are light-absorbing structures disposed in the light absorbing film, and the light-absorbing structures are arranged spaced apart from each other.