Optical system for head-up displays
First Claim
1. An optical system for a head-up display having a collimator for producing a collimated image of one or more display objects and including an optical relay unit for producing an intermediate image of each display object in the focal plane of the collimator, the optical relay unit comprising:
- a first group of relay elements for each display object;
a second group of relay elements for receiving light from each of the first groups of relay elements and focusing said light in the focal plane of the collimator;
and a plurality of optical folding elements for producing a double fold in the optical path between said first and second groups of relay elements, the folding elements comprising one or more first folding elements one for each display object for reflecting light from the display object to a second folding element;
said second folding element positioned to reflect light incident on it at a defined combination of angle of incidence and wavelength, and to transmit display light incident on it at a different combination of angle of incidence and wavelength, and being so disposed that light from at least one display object passes through the second folding element before being reflected by the first folding element to impinge on the second folding element at a different angle of incidence and is hence reflected towards the second group of relay elements.
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Accused Products
Abstract
An optical system for a head-up display for example for producing a collimated image of a crt display on the external view of an aircraft pilot includes an optical relay unit including two elements (11,12) to produce a double fold in its optical axis to reduce the physical size of the relay unit. One of the two units (11), preferably of a diffractive type, is adapted to transmit light of the display color at a first angle of incidence and to reflect such light at a second angle of incidence.
By use of a diffractive element having a narrow band reflectance, the system is extended to include embodiments for combining the display of two different color displays and a full color version using three crts is described.
31 Citations
7 Claims
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1. An optical system for a head-up display having a collimator for producing a collimated image of one or more display objects and including an optical relay unit for producing an intermediate image of each display object in the focal plane of the collimator, the optical relay unit comprising:
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a first group of relay elements for each display object; a second group of relay elements for receiving light from each of the first groups of relay elements and focusing said light in the focal plane of the collimator; and a plurality of optical folding elements for producing a double fold in the optical path between said first and second groups of relay elements, the folding elements comprising one or more first folding elements one for each display object for reflecting light from the display object to a second folding element; said second folding element positioned to reflect light incident on it at a defined combination of angle of incidence and wavelength, and to transmit display light incident on it at a different combination of angle of incidence and wavelength, and being so disposed that light from at least one display object passes through the second folding element before being reflected by the first folding element to impinge on the second folding element at a different angle of incidence and is hence reflected towards the second group of relay elements. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An optical system for a head-up display having a collimator for producing a collimated image of one or more display objects and including an optical relay unit for producing an intermediate image of each display object in the focal plane of the collimator, said optical relay unit comprising:
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a first group of relay elements for each display object; a second group of relay elements for receiving light from each of the first group of relay elements and focusing said light in the focal plane of the collimator; and a plurality of optical folding elements for producing a double fold in the optical path between said first and second groups of relay elements, said folding elements comprising one or more first folding elements, one for each display object, for reflecting light from the display object to a second folding element.
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Specification