An arrangement in which light is directed onto a surface proceeding from a light source by first optics, so that an image is formed which can be detected by second optics, the arrangement having first, second and third partial optics and an optical axis as common optical axis for the first partial optics (22) and second partial optics (24) by which the second optics are formed. The light coming from the third partial optics and incident in the second partial optics encloses an angle relative to the common optical axis at which the third partial optics lie outside of an area traversed by the light reflected by the reflecting surface from the second partial optics (24) to the first partial optics (22).

An imaging device is provided for efficient and accurate conversion of invisible infrared radiation into a visible optical image. In an example, the image device employs an improved configuration of a substrate transmissive to infrared radiation, an infrared lens system, an optical readout radiation/displacement conversion unit for converting the infrared radiation into displacements, a readout optical system for directing readout light towards reflectors of the optical readout radiation/displacement conversion unit. The image device also provides for ease in assembly and calibration by adopting an improved arrangement of the parts.

A reflection type projector includes a light source, a micro mirror device having many micromirrors two-dimensionally arranged, a separation prism and a projection lens. The separation prism is disposed between the light source and the micro mirror device. The separation prism is provided with a first surface on which the illumination light is incident, a second surface whose half part faces to the micro mirror device and the remaining half part is directed to the projection lens, and a third surface. The illumination light passes through the first and second surface to be incident on the micro mirror device. The reflected light from the micro mirror device is incident on the second surface. The separation prism is disposed so that the reflected light by the micromirrors at the ON position totally reflected by the first and third surface and the reflected light by the micromirrors at the OFF position is not totally reflected by the third surfaces. The light totally reflected by the first and third surfaces passes through the second surface to be incident on the projection lens that projects an image onto a screen.

A reflective projector includes a light source, reflective liquid crystal panels, a dichroic prism for separating a light beam from the light source into light beams of predetermined colors by using interference and for synthesizing the light beams of predetermined colors into a light beam, and a projection lens. The reflective projector further includes a first polarizer provided between the light source and the reflective liquid crystal panels and a second polarizer provided between the reflective liquid crystal panels and the projection lens.

In a projection apparatus, a light beam emitted by a light source is guided to a modulation element for forming an image. The light beam emerged from the modulation element is projected onto a screen by a projection lens. An image of the light source is formed as a first light source image by a first optical system. The light beam from the modulation element illuminated with light emanating from the first light source image is imaged by a second optical system as a second light source image at a potion in the vicinity of an aperture of a stop of the projection lens. A peripheral portion of the first light source image is intercepted by another stop located at a potion conjugate with the stop of the projection lens.