Disclosed is an inexpensive, bright, compact, lightweight, high-definition projection-type display device that has a comparatively simple structure but satisfies demands for oblique projection, uniform illumination, a deep focal depth, and magnified projection over a short distance. The display device comprises a light source (1a); an illumination portion (1) consisting of a group of collection angle control components, which comprises at least one optical surface (1c) for receiving a principal ...

A pyrotechnic toy noisemaker detonates an explosive charge on impact without hazards of burning or shrapnel. A container with constricted outlet retains solid particles and releases gaseous products.

An image projecting apparatus comprises an optical element including a first end surface, a second end surface and a reflection surface for connecting the first and second surfaces and constructed so that light beams are incident on the first end surface, and at least some of the light beams are reflected by the reflecting surface and emerge from the second end surface. The apparatus also comprises a reflection type optical modulating device for modulating the light beams from the second end sur...

A projection type image display apparatus for projecting an image onto a screen includes a light source, a beam shape converter, a beam divider, a beam superimposer, a processing unit, and a projection lens. In operation, the light source emits a light beam. The beam shape converter converts a sectional shape of the light beam into a different shape. For example, the beam shape converter can convert a circular cross section into a rectangular cross section. The beam divider then spatially divide...

An illumination apparatus and a projection type display apparatus of lower cost are provided, in which extra-axial aberrations, especially distortion and lateral aberration, are favorably corrected, and the dimensional margin of illumination is suppressed to enhance the utilization factor of light. The illumination apparatus includes a first group of lenses which includes a meniscus lens having a positive refracting power, a second group of lenses which includes first lens means having a negativ...

A projector is provided with an illuminator, dichroic mirror for splitting illumination light into a plurality of light components, a plurality of light propagating paths in which the plurality of light components are introduced to corresponding image panels. In a propagating path having a largest distance, there are provided a relay optical system having a relay lens and a field lens. The relay lens and/or the field lens have a refractive index of 1.75 or more.

A projection display unit which has a light source, a reflecting mirror for reflecting a light pencil from the light source, a first multilens array for dividing a light pencil gathered by the reflecting mirror into a plurality of light pencils, a second multilens array for forming an image of the first multilens array, a polarization conversion element for converting light pencils in an irregular polarization state into linearly polarized light, a condenser having positive power for superposing...

A projecting device, particularly for use in photogrammetry, employs a Fresnel condensor for illuminating a picture carrier which is imaged through an objective, including a diaphragm, onto a projection table. At least half of the illumination rays entering said objective, is suppressed by said diaphragm. The Fresnel condensor and the severe stopping-down of the objective produce interfering chromatical effects on the projection table. Said chromatical effects are eliminated either by means of a...

A family of condenser lenses for an overhead projector (OHP) are designed to balance overall brightness in the projected image versus uniformity of illumination. The lenses are plano-convex and aspheric, and their conic constant is a function of the radius of curvature. The radius of curvature is further selected from a range which depends upon the size of the stage of the OHP. Preferred values of other parameters of the lens and OHP optical system are selected to complement the lens design. The...

A lens construction for a character projection unit and with the character projection unit including a plurality of light sources mounted in side-by-side relation, a plurality of corresponding condensor lenses, a plurality of corresponding projection lenses, and a plurality of corresponding characters disposed between the light sources and projection lenses to form a number of separate and individually complete projection systems within a confined volume, including at least one condensing lens p...