Provided is a reflective screen and a projection image display system in which a transmittance of light can be selectively changed, a transmittance in a transparent state is sufficiently high, a voltage does not need to be applied constantly, and a voltage is applied to decrease a transmittance of light in a case where the reflective screen is irradiated with video light. The reflective screen includes: a light reflecting layer that is formed of a cholesteric liquid crystal layer and where a selective reflection wavelength at a polar angle of 60° is present in a visible range, in which senses of helix of all of cholesteric liquid crystal layers are the same and Expression (1) is satisfied; and a transparent first electrode, a transparent second electrode, and a light control layer that are provided on a rear side with respect to the light reflective layer, the light control layer being disposed between the first electrode and the second electrode, in which the light control layer includes a polymer network and liquid crystal molecules and changes between a first state where light is scattered and a second state where transmission of light is allowed by changing a magnitude of a voltage applied, the polymer network having a three-dimensional net shape having a plurality of domains, and the liquid crystal molecules being positioned in the domains.

R[−60,40](550)/R[−60,30](550)≥1.5  Expression (1)

The room includes: a ceiling; a floor; and a wall having a pair of wall surfaces opposite to each other, and another pair of wall surfaces opposite to each other in a direction intersecting the pair of wall surfaces. One of the pair of wall surfaces and the other pair of wall surfaces has a window. The wall surface opposite to the wall surface having the window has arranged thereon a first screen. An inner side of the window, and a projection-side surface of the first each has arranged thereon a polarizing plate. An absorption axis direction of a polarizer of the polarizing plate of the window, and an absorption axis direction of a polarizer of the polarizing plate of the first screen and/or an absorption axis direction of a polarizer of the polarizing plate of the second screen are substantially perpendicular or parallel to each other.

The room includes: a ceiling; a floor; and a wall having a pair of wall surfaces opposite to each other, and another pair of wall surfaces opposite to each other in a direction intersecting the pair of wall surfaces. One of the pair of wall surfaces and the other pair of wall surfaces has a window. The wall surface opposite to the wall surface having the window has arranged thereon a first screen. An inner side of the window, and a projection-side surface of the first each has arranged thereon a polarizing plate. An absorption axis direction of a polarizer of the polarizing plate of the window, and an absorption axis direction of a polarizer of the polarizing plate of the first screen and/or an absorption axis direction of a polarizer of the polarizing plate of the second screen are substantially perpendicular or parallel to each other.

Provided are: an image display apparatus that can display augmented reality in a virtual image is superimposed on a bright real scene; and AR glasses including the image display apparatus. The image display apparatus includes: a display element; and a reflective polarization diffraction element that reflects an image displayed by the display element, in which the polarization diffraction element has a region where a period of a diffraction structure decreases in a direction away from the display element.

A system includes a view screen with polarized output. The view screen may include a projected view screen or writing-surface view screen. A window capable of blocking the polarized output at least in part cloaks the view screen to frustrate viewing of the view screen through the window. In some cases, the window includes an array of panels capable of blocking multiple polarizations. The array may disrupt multiple different polarized view screen outputs while maintaining transparency to unpolarized light. In some cases, the window capable of blocking polarized output may be paired with view screen cover that converts view screen output in an unblocked polarization to one of the one or more polarizations blocked by the window.

A system includes a view screen with polarized output. The view screen may include a projected view screen or writing-surface view screen. A window capable of blocking the polarized output at least in part cloaks the view screen to frustrate viewing of the view screen through the window. In some cases, the window includes an array of panels capable of blocking multiple polarizations. The array may disrupt multiple different polarized view screen outputs while maintaining transparency to unpolarized light. In some cases, the window capable of blocking polarized output may be paired with view screen cover that converts view screen output in an unblocked polarization to one of the one or more polarizations blocked by the window.

An information display system having acute-angled diffusion characteristics configured to display an image to inside or outside of a space via a transparent projected member, the information display system including an image projection apparatus, a transparent sheet provided on an inner surface of a display region set on a part of the projected member; and a light direction changing unit that directs a direction of image light toward the transparent sheet of the display region, the image projection apparatus including an image light characteristic converting unit, and an image light control film that restricts an emission direction of the image light being provided on an upper surface of the image projection apparatus, so that the image light is not directly delivered to an observer and the image light reflected by the transparent sheet is recognized by the observer.

An information display system having acute-angled diffusion characteristics configured to display an image to inside or outside of a space via a transparent projected member, the information display system including an image projection apparatus, a transparent sheet provided on an inner surface of a display region set on a part of the projected member; and a light direction changing unit that directs a direction of image light toward the transparent sheet of the display region, the image projection apparatus including an image light characteristic converting unit, and an image light control film that restricts an emission direction of the image light being provided on an upper surface of the image projection apparatus, so that the image light is not directly delivered to an observer and the image light reflected by the transparent sheet is recognized by the observer.

A compact projector for use in a head-mounted display device consists of an illumination section, a relay section, and a numerical aperture expander (NAE). The illumination section includes one or more illumination sources, a scanner, and a focusing lens which converges light onto an image plane. The NAE receives light from the illumination section, expands the average numerical aperture of the light, and transmits the light to the relay section. The relay section includes optical elements which collimate light from the image plane onto an exit pupil. The projector may also be fitted with lateral-axis and/or vertical-axis stops which prevent stray light from passing through the exit pupil.

A compact projector for use in a head-mounted display device consists of an illumination section, a relay section, and a numerical aperture expander (NAE). The illumination section includes one or more illumination sources, a scanner, and a focusing lens which converges light onto an image plane. The NAE receives light from the illumination section, expands the average numerical aperture of the light, and transmits the light to the relay section. The relay section includes optical elements which collimate light from the image plane onto an exit pupil. The projector may also be fitted with lateral-axis and/or vertical-axis stops which prevent stray light from passing through the exit pupil.