Disclosed is a rear projection screen that includes a plurality of tapered waveguides and a light absorbing layer disposed over the tops of the waveguides, but that does not completely fill the spaces between the waveguides, thereby forming an interstitial low index region under the light absorbing layer and between the waveguides. The low index interstitial region can include air or a material that has a lower index of refraction than the waveguide material. This rear projection screen construction can give rise to increased efficiency and higher contrast, as well as allow for more design freedom in constructing screens that have desired characteristics such as viewing angle, viewing asymmetry, and the like. Also disclosed are methods for making the described microstructured rear projection screen.
Provided is a light diffusion sheet or film capable of preventing the reflection of an external light that has entered from a light emission surface and also capable of obtaining a high gain. Also provided is a projection screen using the light diffusion sheet or film. The light diffusion sheet or film has formed thereon, either one-dimensionally or two-dimensionally, a plurality of unit lenses. The unit lens is substantially trapezoidal in cross section. The lower bottom of the trapezoid is made to be a light incidence portion and the upper bottom thereof is made to be a light emission portion. The unit lens is formed using a material having a prescribed refractive index N1. One portion, the cross section of which is triangular and located between an adjacent two of the unit lenses, is formed using a material having a refractive index N2 lower than refractive index N1 and having added thereto light absorption particles. When it is assumed that T represents the length of the upper bottom of the trapezoid; H represents the height of the upper bottom thereof; and .theta. represents the angle defined by the slant of the trapezoid with respect to a line normal to the light emission portion, the following relationships apply: and the surface of the light incidence portion has performed thereon embossing processing.
A light diffusion sheet or film including a plurality of unit lenses formed of a material having a refractive index N1, each unit lens having a trapezoidal cross-section. At least one between lens portion, having a triangular cross-section, positioned between two of the unit lenses. The between lens portion is formed of a material having a refractive index N2 that is less than N1. If .theta. represents an angle defined by a side of the trapezoidal cross-section and a line normal to a base of the trapezoidal cross-section, then sin(90-.theta.)>N2/N1 and N1<1/sin(2.theta.).
The present invention is to provide a light guide pillar disposed on a circuit board of an electronic apparatus having a light emitting element disposed thereon, where the light guide pillar includes a bulk opaque and disposed on the circuit board for covering the light emitting element and a pillar with one end inserted into the bulk while the other end thereof extended outside of the electronic apparatus, enabling the light source generated from the light emitting element to be guided and displayed outside of the electronic apparatus via the light guide pillar and enabling the bulk to stop the light source emitted from the light emitting element from dispersing. Therefore, the light source can be guided to outside of the electronic apparatus without interference.
A film for a screen has a light transmitting substrate and a plurality of structures disposed on the substrate. An optical material at least partially fills cavities between the structures. A method of forming a film includes providing a light transmitting substrate having a plurality of structures disposed thereon and at least partially filling the cavities therebetween with an optical material.
