Abstract: An optical system and a projection system incorporating same are disclosed. The optical system includes a light source that is capable of emitting light. The emitted light includes one or more substantially collimated discrete light beams. The optical system further includes a lenslet array for receiving and transmitting the emitted light. Each discrete light beam in the emitted light has an intensity full width at half maximum (FWHM) at the lenslet array that covers at least a portion of a plurality of lenslets in the lenslet array. The optical system further includes an optical element for receiving the transmitted light from an input face of the optical element. The optical element homogenizes the received light and transmits the homogenized light from an output face of the optical element.

Abstract: An illumination system including a plurality of light source modules each including a light-emitting surface and a dome lens, an illumination target and at least one optical device disposed between at least one of the light source modules and the illumination target. Each optical device includes an alignment mechanism engaging the dome lens, and at least one optical element fixed to the alignment mechanism, the optical element having an optical axis. The alignment mechanism is releasably securable between a first position and a second position relative to the dome lens for adjusting the optical device between the first position where the optical axis passes through the light-emitting surface and the illumination target, and second position where the optical axis passes through the light-emitting surface.

Abstract: Illumination systems are disclosed, which include illumination channels of different colors and at least one image-forming device. Each illumination channel, in turn, includes a bank of light sources, and the image-forming device is disposed to receive illumination from at least one of the illumination channels. At least one of the illumination channels includes an optical element, such as an optical element having optical power or a homogenizing optical element, that is not shared with any other illumination channel and is preferentially constructed or preferentially positioned for the color of its illumination channel.

Abstract: A color-splitting optical element is disclosed that includes a first prism having a first transmissive curved outer side, a second transmissive curved outer side and an inner side. The color-splitting optical element also includes a second prism having a first transmissive curved outer side, a second side and an inner side. A dichroic element is disposed between the inner side of the first prism and the inner side of the second prism. The first transmissive curved outer side of the first prism is disposed generally opposite the first transmissive curved outer side of the second prism along a first direction and the second transmissive curved outer side of the first prism is disposed generally opposite the second side of the second prism along a second direction. Also disclosed are optical systems utilizing such color-splitting optical elements.

Abstract: Multi-directional optical elements are disclosed that include a body having a first side having a first curvature, a second side having a second curvature, a third side having a third curvature, and a fourth side having a fourth curvature. The second side is disposed generally opposite the first side along a first direction and a fourth side is disposed generally opposite the third side along a second direction, the second direction being different from the first direction. Also disclosed are optical systems utilizing such multi-directional optical elements.

Abstract: High pressure mercury arc lamps are commonly used as the illumination source in many projection systems. Such lamps may be deficient in either output power or spectrum, and so it is desirable to combine the light from the lamp with light from a second light generator. The second light generator may be another mercury lamp or a solid state source, such as one or more light emitting diodes. Different ways of combining light from two light generators are described. The second light source may be an arrangement of a number of red LEDs that supplements the red light produced by the mercury light. A tunnel integrator may be used to homogenize the combined light beam and to reduce the angular separation between the light beams from the two light generators.

Abstract: Methods are provided for optimizing the spectrum of a light source used in a projection display system in order to reduce the light loss associated with color splitting/recombination in the system. Projection systems designed in accordance with such methods are also disclosed.

Abstract: In an image projection system, there are at least two light illumination units producing illumination light beams of respective first and second primary colors. A first beamsplitter is disposed to split at least a portion of the first illumination light beam into sub-beams, one of which is directed to a first image-forming panel. The other sub-beam is combined with at least some of the second illumination light beam to form a light beam of mixed light that illuminates the image-forming panel. In some embodiments, the first beamsplitter is a polarizing beamsplitter.

Abstract: An illumination system, useful for generating illumination light in an image-projection system, has at least a first image-forming panel. A first array of light emitting elements, for example light emitting diodes (LEDs), generates a first light beam associated with a first wavelength range. A second array of light emitting elements generates a second light beam associated with a second wavelength range. The second array of light emitting elements comprises at least a first light emitting element generating light in the second wavelength range and a second light emitting element generating light in the first wavelength range. The center wavelength of the second light emitting element may be closer in value to the center wavelength of a light emitting element in the first array than to the center wavelength of the first light emitting element.

Abstract: Illumination systems are disclosed that include a light source or a bank of light sources having a non-radially symmetrical aperture having a longer dimension and a shorter dimension, such that the light source or bank of light sources produces illumination with a non-radially symmetrical angular intensity distribution having a larger angular dimension and a smaller angular dimension. The illumination systems include an integrator having an entrance end optically connected to the bank of light sources, an exit end, and a dimension that experiences a larger increase from the entrance end to the exit end. The integrator is disposed so that the dimension experiencing the larger increase is substantially aligned with the larger angular dimension of the illumination produced at the entrance end of the integrator.

Abstract: High pressure mercury arc lamps are commonly used as the illumination source in many projection systems. Such lamps may be deficient in either output power or spectrum, and so it is desirable to combine the light from the lamp with light from a second light generator. The second light generator may be another mercury lamp or a solid state source, such as one or more light emitting diodes. Different ways of combining light from two light generators are described. The second light source may be an arrangement of a number of red LEDs that supplements the red light produced by the mercury light. A tunnel integrator may be used to homogenize the combined light beam and to reduce the angular separation between the light beams from the two light generators.

Abstract: Multi-directional optical elements are disclosed that include a body having a first side having a first curvature, a second side having a second curvature, a third side having a third curvature, and a fourth side having a fourth curvature. The second side is disposed generally opposite the first side along a first direction and a fourth side is disposed generally opposite the third side along a second direction, the second direction being different from the first direction. Also disclosed are optical systems utilizing such multi-directional optical elements.

Abstract: An LED illumination unit uses a first reflector comprising a reflecting surface formed as a surface of revolution about a first revolution axis. The LED emits light about a first LED axis towards the reflecting surface of the first reflector. The first LED axis is non-parallel to the first revolution axis and the light emitting area of the first LED unit is positioned substantially at a focus of the reflecting surface. The reflector may also have two or more reflecting surfaces for collecting and directing light from two or more respective LEDs.

Abstract: The invention is an illumination system including a plurality of light source modules, each light source module includes a light-emitting surface and a dome lens. Additionally, the illumination system includes an illumination target and at least one optical device disposed between at least one of the light source modules and the illumination target. Each optical device includes an alignment mechanism engaging the dome lens. Additionally, each optical device includes at least one optical element having optical power such as a lens, fixed to the alignment mechanism, the optical element having an optical axis. The alignment mechanism is releasably securable between a first position and a second position relative to the dome lens. The optical device is adjustable between the first and second position. In the first position, the optical axis passes through the light-emitting surface and through the illumination target, and in the second position, the optical axis passes through the light-emitting surface.

Abstract: An illumination system is based on multiple light emitting diodes (LEDs), arranged in a row, to side-illuminate respective reflectors. The illumination system is particularly useful as a vehicle headlamp. In some embodiments, the reflectors may be curved, for example paraboloidal, to collect the light, but truncated in the direction along the row: this allows for closer packing of the LEDs. In other embodiments, the different reflectors point in different directions so as to spread the combined light beams across the driver's field of view. In other embodiments, the reflectors for the different LEDs may be formed on a single molded body.

Abstract: A projection display system employs one or more color modifying aperture stops, such as apodizing aperture stops, to provide high contrast, balanced color and high throughput. One projection system includes a reflective liquid crystal-on-silicon light valve positioned with a polarizing beam splitter, such as a wire grid polarizing beam splitter, for each of the primary color component light paths to separately impart image information into each of the primary color components of light. A color combiner receives and combines the primary color components of light with imparted image information to provide light representing a polychromatic display image. At least one aperture stop is positioned along at least one of the primary color component light paths to balance relative intensities of the primary color components of light.

Abstract: An illumination system, used for illuminating a target area, includes a plurality of light generating elements and a plurality of light collection units disposed to collect light from respective light generating elements. Imaging lens units are disposed to relay images of respective light collection units to the target area, light from different light generating elements overlapping at the target area. In some embodiments, the illumination system also includes color combining elements to combine light from differently colored light generating elements. The illumination system may be used in a projection system, with the light from the illumination system incident on an image-forming device placed at the target area.

Abstract: A compound polarization beam splitter (33) for use with a reflective, polarization-modulating, imaging device (10), e.g., a LCoS device, is provided. The compound PBS has: (a) an input prism (20); (b) an output prism (30), and (c) a polarizer (13), which is located between the two prisms (20,30) and which may be a wire grid polarizer (13a) or a multi-layer reflective polarizer (13b). Polarized illumination light (11) enters the input prism (20) through a first surface (21) and undergoes total internal reflection at a second surface (22) before being reflected from the polarizer (13) and polarization-modulated at the imaging device (10). The polarizer's tilt angle (?) is less than 45°, which reduces astigmatism and the required back working distance of the system's projection lens (74).

Abstract: Optical systems for projection optical devices which employ reflective LcoS panel (9, 14, 15) are provided. The systems provide high contrast, compact size, and high light throughput.

Abstract: A rear projection screen for use with a projection lens which has an exit pupil (23) is provided. The screen has a light entering side and a light exiting side and comprises in order from said light entering side to said light exiting side: (a) a Fresnel structure (11); (b) a lenslet array (13); and (c) an opaque layer (15) comprising a plurality of pinholes, said pinholes being at locations which correspond to the images of the exit pupil formed by the combination of the Fresnel structure and the lenslet array.