A projection apparatus, including an illumination system, a light valve, a first movable reflector, a first projection lens, a second projection lens, and a driving module, is provided. The illumination system is configured to provide an illumination light beam. The driving module is connected to the first movable reflector and is configured to drive the first movable reflector to move. The projection apparatus has a first projection mode and a second projection mode for being performed. In the first projection mode, the driving module controls the first movable reflector to move to a first position. In the second projection mode, the driving module controls the first movable reflector to move to a second position, and the first movable reflector is not located on a transmission path of an image light beam.

A projection apparatus, including an illumination system, a light valve, a first movable reflector, a first projection lens, a second projection lens, and a driving module, is provided. The illumination system is configured to provide an illumination light beam. The driving module is connected to the first movable reflector and is configured to drive the first movable reflector to move. The projection apparatus has a first projection mode and a second projection mode for being performed. In the first projection mode, the driving module controls the first movable reflector to move to a first position. In the second projection mode, the driving module controls the first movable reflector to move to a second position, and the first movable reflector is not located on a transmission path of an image light beam.

A phase difference compensation element, including: a transparent substrate; a first optical anisotropic layer that includes an inorganic material, and has a C-plate retardance; and a second optical anisotropic layer that includes an inorganic material, and includes an oblique angle vapor deposition film that does not have an O-plate retardance, wherein the phase difference compensation element including the first optical anisotropic layer and the second optical anisotropic layer in combination has a quasi-O-plate retardance.

An image display apparatus according to an embodiment of the present technology includes an optical modulator, an optical device, and a sensor unit. The optical device splits a modulated light beam modulated by the optical modulator into a first split light beam and a second split light beam, the first split light beam and the second split light beam each travelling in a different direction, and prevents a light beam, which backwardly travels on an optical path of the first split light beam and enters the optical device, from travelling along an optical path of the second split light beam. The sensor unit is disposed on the optical path of the second split light beam and detects a state of the second split light beam.

An image display apparatus according to an embodiment of the present technology includes an optical modulator, an optical device, and a sensor unit. The optical device splits a modulated light beam modulated by the optical modulator into a first split light beam and a second split light beam, the first split light beam and the second split light beam each travelling in a different direction, and prevents a light beam, which backwardly travels on an optical path of the first split light beam and enters the optical device, from travelling along an optical path of the second split light beam. The sensor unit is disposed on the optical path of the second split light beam and detects a state of the second split light beam.

An optical system of a semi-vertical single LCD (liquid crystal display) projector includes a projection light source, a condenser, an illuminating reflector, a collimating lens, a heat reflecting glass, an LCD light valve, a field lens, an imaging reflector and a projection lens, all of which are set in sequence according to a direction of light, wherein the illuminating reflector reflects and turns light irradiating the LCD light valve in up and down directions, and the imaging reflector performs mirror reflection and turning on light emitted by the LCD light valve in left and right directions. The present invention obtains a new optical system structure, creates a novel stacking and a novel projector appearance, and has low cost, small size and complete integration.

An optical system of a semi-vertical single LCD (liquid crystal display) projector includes a projection light source, a condenser, an illuminating reflector, a collimating lens, a heat reflecting glass, an LCD light valve, a field lens, an imaging reflector and a projection lens, all of which are set in sequence according to a direction of light, wherein the illuminating reflector reflects and turns light irradiating the LCD light valve in up and down directions, and the imaging reflector performs mirror reflection and turning on light emitted by the LCD light valve in left and right directions. The present invention obtains a new optical system structure, creates a novel stacking and a novel projector appearance, and has low cost, small size and complete integration.

A head-up display system includes a projection module including a display panel to project an image displayed on the display panel, a reflective optical element that reflects at least a part of the image, an optical member located between the projection module and the reflective optical element and having light-shielding capability, and a controller that controls the light-shielding capability of the optical member.

An object of the present invention is to provide a projection apparatus capable of appropriately performing control relating to a rotation state and/or a movement state of a projection lens. A projection apparatus according to an aspect of the present invention includes a housing; a light source; a control unit; and a projection lens attached to the housing, the projection lens having a holder, a detection unit that detects a rotation state of the holder, an emission optical system, and a locking mechanism unit that brings rotation of the holder into a locked state or an unlocked state. The projection lens is displaceable between a first position at which a rotation state of the holder is a housed state in which the emission optical system faces the housing and a second position at which the emission optical system does not face the housing by rotating the holder. The second position includes an upper position at which the emission optical system faces an upper side in a vertical direction. The control unit turns off the light source when a rotation state of the holder is the first position. The control unit turns on the light source when the rotation state of the holder is at the upper position. When the light source is turned on in the housed state in which the emission optical system faces the housing, the light emitted from the emission optical system hits the housing, and the temperatures of the projection lens and the housing may increase, which may cause an adverse effect. However, when the rotation state is the housed state, the control unit turns off the light source, thereby preventing the adverse effect.

An image display apparatus (100) according to the present invention includes a display unit and a projection unit. The display unit includes a curved first screen (43) and a curved second screen (44), the first screen extending along a predetermined axis (1), the curved screen having transparency and being disposed on a front side of the first screen (43) with a gap interposed therebetween. The projection unit includes an emitter (11) that emits light for displaying a first image from a region on the predetermined axis (1) and a second image superimposed on the first image, projects the first image onto the first screen (43), and projects the second image onto the second screen (44).