Abstract: An optical touch apparatus includes at least one light source, at least one light guide unit, at least one optical detector, and a light reducing structure. The light source is disposed beside a display area of a display and capable of providing a light beam. The light guide unit is disposed beside the display area and in a transmission path of the light beam. The light guide unit has a first surface, a second surface, and a light incident surface. The light beam is capable of entering the light guide unit through the light incident surface and being transmitted to a sensing space in front of the display area through the first surface. The optical detector is disposed beside the display area. The light reducing structure covers a portion of the first surface adjacent to the light incident surface.

Abstract: An optical touch apparatus is adapted to a display apparatus. The optical touch apparatus includes at least one light source, at least one light guide unit, and at least one optical detector. The light source is disposed beside a display area of the display apparatus and capable of providing a light beam. The light guide unit is disposed beside the display area in a transmission path of the light beam and has a first surface, a second surface opposite to the first surface, and a light incident surface. The light incident surface connects the first and second surfaces. The light beam is capable of entering the light guide unit through the light incident surface and is transmitted to a sensing space in front of the display area. The optical detector is disposed beside the display area to sense an intensity variation of the light beam in the sensing space.

Abstract: A light guide plate includes a first light guide body having a light incident plane, a first connection surface, and recesses and a second light guide body having a light emitting plane, a second connection surface opposite to the light emitting plane, and protrusions. The recesses are disposed on the first connection surface. Each of the recesses has a bottom plane parallel to the light emitting plane. The light incident plane intersects with the first connection surface. The first connection surface contacts the second connection surface. The protrusions are disposed on the second connection surface and fill the recesses respectively. Cross-sectional planes of each protrusion parallel to the light emitting plane decrease gradually in a direction towards the bottom plane of the corresponding recess. A terminal thickness of the second light guide body is less than that of the first one.

Abstract: A projection screen includes a reflection layer, a light absorbing structure, a plurality of light diffusion layers, and a lens structure. The light absorbing structure is disposed on the reflection layer and has a plurality of apertures. A part of the reflection layer is exposed via the apertures. The light diffusion layers have a first index of refraction. Each of the light diffusion layer is disposed in the corresponding aperture and contacts the corresponding reflection layer exposed via the corresponding aperture. The lens structure is disposed on the light diffusion layers and the light absorbing structure. A light incidence side of the lens structure includes a plurality of convex lenses. The convex lenses are respectively corresponding with the light diffusion layers. The lens structure has a second index of refraction, and the second index of refraction is smaller than the first index of refraction.

Abstract: A screen of a projector having a substrate and a plurality of asymmetric optical structures is provided. There is a plurality of light absorbing zones and a plurality of reflective zones alternatively disposed on a surface of the substrate facing the projector. The asymmetric optical structures are disposed on the surface of the substrate and correspond to the reflective zones, respectively. The asymmetric optical structure has a first curved surface and a second curved surface, and the first curved surface protrudes toward the projector for converging an incident light from the projector on the reflective zone, and the second curved surface is disposed at a side of the first curved surface away from the projector for refracting a reflective light from the reflective zones toward the normal direction of the surface of the substrate.