Helmet systems with eyepiece and eye position sensing means
First Claim
1. A helmet system comprising a helmet and, carried by the helmet, an optical arrangement incorporating:
- an eyepiece having a rearwardly facing, concavely curved, first element exhibiting substantial reflectivity to light within a narrow visible waveband and substantial transmissivity to visible light other than that within the said visible waveband;
an areally extensive bright-image-forming source emissive of light within said visible waveband; and
between said source and said eyepiece, an optical relay arrangement including an inclined reflector operable to fold rays of light emitted by said source within said visible waveband for incidence with said eyepiece, said optical relay arrangement per se and the position of said optical relay arrangement relative to said source and said eyepiece being such as to form an intermediate real image of said source substantially coincident with the principal focal plane of said first element, whereby said source appears at an eye position defined by said helmet in the line-of-sight through said eyepiece as a virtual image at infinity, wherein;
said inclined reflector is substantially transmissive to infra-red radiation within an infra-red waveband;
said eyepiece incorporates a second rearwardly facing concavely curved element which is substantially reflective to infra-red radiation within said infra-red waveband and substantially transmissive to visible light;
there is located on the side of said inclined reflector remote from said eyepiece an areally extensive sensor operable to develop an electrical output representative of the position of incidence within a sensing area of the sensor of infra-red radiation, within said infra-red waveband, brought substantially to focus on said sensing area; and
there is substantially coincident with the principal focus of said second element an infra-red source emissive of infra-red radiation within said infra-red waveband, the arrangement being such that when said system is in use with an eye located at said eye position, infra-red radiation from said infra-red source is reflected collimated by said second element through said eyepiece to said eye position, partially reflected by said eye at said eye position and brought substantially to focus at a position within the sensing area of said sensor, said position corresponding to the angular position of said eye with respect to helmet axes.
1 Assignment
0 Petitions
Accused Products
Abstract
There is disclosed two helmet systems, each comprising a helmet (11) and, carried by the helmet (11), an optical arrangement (13). In each system, the optical arrangement (13) both provides a collimated display superimposed on the helmet wearer'"'"'s view of the forward scene through an eyepiece (15 or 50) of the arrangement (13), and senses the angular position of that eye of the helmet wearer looking through the eyepiece (15 or 50) with respect to the helmet axes. The optical arrangement (13) senses such angular position by sensing the position, within a sensing area of a sensor (37 or 72), of the point focus of infra-red radiation, from an infra-red point source (35 or 71A), reflected by the eye, and producing an electrical output representative of this position. In one helmet system the eyepiece (15) is of the open optics type and in the other the eyepiece (50) is of the solid optics type.
178 Citations
3 Claims
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1. A helmet system comprising a helmet and, carried by the helmet, an optical arrangement incorporating:
- an eyepiece having a rearwardly facing, concavely curved, first element exhibiting substantial reflectivity to light within a narrow visible waveband and substantial transmissivity to visible light other than that within the said visible waveband;
an areally extensive bright-image-forming source emissive of light within said visible waveband; and
between said source and said eyepiece, an optical relay arrangement including an inclined reflector operable to fold rays of light emitted by said source within said visible waveband for incidence with said eyepiece, said optical relay arrangement per se and the position of said optical relay arrangement relative to said source and said eyepiece being such as to form an intermediate real image of said source substantially coincident with the principal focal plane of said first element, whereby said source appears at an eye position defined by said helmet in the line-of-sight through said eyepiece as a virtual image at infinity, wherein;
said inclined reflector is substantially transmissive to infra-red radiation within an infra-red waveband;
said eyepiece incorporates a second rearwardly facing concavely curved element which is substantially reflective to infra-red radiation within said infra-red waveband and substantially transmissive to visible light;
there is located on the side of said inclined reflector remote from said eyepiece an areally extensive sensor operable to develop an electrical output representative of the position of incidence within a sensing area of the sensor of infra-red radiation, within said infra-red waveband, brought substantially to focus on said sensing area; and
there is substantially coincident with the principal focus of said second element an infra-red source emissive of infra-red radiation within said infra-red waveband, the arrangement being such that when said system is in use with an eye located at said eye position, infra-red radiation from said infra-red source is reflected collimated by said second element through said eyepiece to said eye position, partially reflected by said eye at said eye position and brought substantially to focus at a position within the sensing area of said sensor, said position corresponding to the angular position of said eye with respect to helmet axes. - View Dependent Claims (2, 3)
- an eyepiece having a rearwardly facing, concavely curved, first element exhibiting substantial reflectivity to light within a narrow visible waveband and substantial transmissivity to visible light other than that within the said visible waveband;
Specification