Ophthalmometer having alternative viewing and measuring systems and including an improved illumination system

Claim 1

A device for measuring the curvature of a cornea or a contact lens when the device is in a measuring mode of operation and viewing a cornea or a contact lens with magnification when the device is in a viewing mode of operation comprising: a target; means for reflecting an image of the target from a cornea wheN the curvature of a cornea is to be measured; a magnifying lens for magnifying the image of the target reflected from the cornea to be measured; an eye piece for viewing the magnified image of the target reflected from the cornea; an achromatic wedge for use when the device is in a measuring mode of operation, said wedge being positioned in optical alignment between said magnifying lens and said eye piece; means for directing light traveling between said magnifying lens and said eye piece away from said wedge and thereby prevent light reflected from a cornea from passing through said wedge comprising four mirrors, three of which are fixed and one of which is movable, said movable mirror being movable to two alternate rest positions, a first rest position forming a mirror system in which the movable mirror and the fixed mirrors are the equivalent of a prism system which consists of two right angle prisms placed at right angles to each other, said movable mirror when in said first position being in optical alignment with light passing through said magnifying lens so that light passing through said lens strikes said movable mirror which reflects light successively to each of said three fixed mirrors, said movable mirror when in said second position being out of optical alignment with light passing through said magnifying lens, a lever externally mounted on said device, said means for directing the path of light away from said wedge being switchable by the action of said lever to enable an operator to switch said device from a measuring mode of operation to a viewing mode of operation by controllably causing light to pass through said magnifying lens, wedge and eye piece when said lever switches the device to a measuring mode of operation and controllably causing light to pass through said magnifying lens and eye piece without passing through said wedge when said lever switches the device to a viewing mode of operation and a means for illuminating an object to be viewed with either of two different modes of illumination, a diffused mode and an undiffused mode comprising a light source for selectively providing white and ultraviolet light and which includes an incandescent bulb, a diffuser positioned over said incandescent bulb, and an aperture on the diffuser for permitting a stream of undiffused light to radiate from said incandescent bulb, an elliptical reflector positioned to reflect light from said light source which passes through said diffuser toward the object to be illuminated, a reflecting surface for directing said stream of undiffused light on to the object to be viewed, a movable shutter which can be positioned in two alternate rest positions, a first rest position blocking the optical path between said aperture and the object, and the second rest position blocking the optical path between said diffuser and said elliptical reflector, means for moving said shutter from said first position to said second position and vice versa to selectively illuminate the object with diffused light and undiffused light, and an interference type ultraviolet filter which can be positioned into and out of said stream of light, said interference ultraviolet filter blocking a substantial amount of non-ultraviolet light and permitting ultraviolet light to pass therethrough to illuminate the object with ultraviolet light when said interference type ultraviolet filter is positioned in said stream of light, said object being illuminated with white light when said interference type ultraviolet filter is positioned out of said stream of light.

Claim 2

A device for measuring the curvature of a cornea or a contact lens when the device is in a measuring mode of operation and viewing a cornea or a contact lens with magnification when the device is in a viewing mode of operation comprising: a target; means for reflecting an image of the target from a cornea wheN the curvature of a cornea is to be measured; a magnifying lens for magnifying the image of the target reflected from the cornea to be measured; an eye piece for viewing the magnified image of the target reflected from the cornea; an achromatic wedge for use when the device is in a measuring mode of operation, said wedge being positioned in optical alignment between said magnifying lens and said eye piece; means for directing light traveling between said magnifying lens and said eye piece away from said wedge and thereby prevent light reflected from a cornea from passing through said wedge comprising four mirrors, three of which are fixed and one of which is movable, said movable mirror being movable to two alternate rest positions, a first rest position forming a mirror system in which the movable mirror and the fixed mirrors are the equivalent of a prism system which consists of two right angle prisms placed at right angles to each other, said movable mirror when in said first position being in optical alignment with light passing through said magnifying lens so that light passing through said lens strikes said movable mirror which reflects light successively to each of said three fixed mirrors, said movable mirror when in said second position being out of optical alignment with light passing through said magnifying lens, a lever externally mounted on said device, said means for directing the path of light away from said wedge being switchable by the action of said lever to enable an operator to switch said device from a measuring mode of operation to a viewing mode of operation by controllably causing light to pass through said magnifying lens, wedge and eye piece when said lever switches the device to a measuring mode of operation and controllably causing light to pass through said magnifying lens and eye piece without passing through said wedge when said lever switches the device to a viewing mode of operation and a means for illuminating an object to be viewed with either of two different modes of illumination, a diffused mode and an undiffused mode comprising a light source for selectively providing white and ultraviolet light and which includes an incandescent bulb, a diffuser positioned over said incandescent bulb, and an aperture on the diffuser for permitting a stream of undiffused light to radiate from said incandescent bulb, an elliptical reflector positioned to reflect light from said light source which passes through said diffuser toward the object to be illuminated, a reflecting surface for directing said stream of undiffused light on to the object to be viewed, a movable shutter which can be positioned in two alternate rest positions, a first rest position blocking the optical path between said aperture and the object, and the second rest position blocking the optical path between said diffuser and said elliptical reflector, means for moving said shutter from said first position to said second position and vice versa to selectively illuminate the object with diffused light and undiffused light, and an interference type ultraviolet filter which can be positioned into and out of said stream of light, said interference ultraviolet filter blocking a substantial amount of non-ultraviolet light and permitting ultraviolet light to pass therethrough to illuminate the object with ultraviolet light when said interference type ultraviolet filter is positioned in said stream of light, said object being illuminated with white light when said interference type ultraviolet filter is positioned out of said stream of light.

Claim 9

The device as set forth in calim 7 wherein both said movable mirrors are positionable in two alternate positions of rest, a second position being the position in which the mirrors are positioned to enable the device to be in a measuring mode of operation with the first position being the position in which the mirrors are positioned to enable the device to be in a viewing mode of operation, said mirrors being oriented when in said first position so that light reflected from a cornea to be viewed strikes one movable mirror which changes the direction of the path of travel of light away from said wedges, the other movable mirror reflecting light through said eye piece.

Claim 10

The device as set forth in calim 7 wherein both said movable mirrors are positionable in two alternate positions of rest, a second position being the position in which the mirrors are positioned to enable the device to be in a measuring mode of operation with the first position being the position in which the mirrors are positioned to enable the device to be in a viewing mode of operation, said mirrors being oriented when in said first position so that light reflected from a cornea to be viewed strikes one movable mirror which changes the direction of the path of travel of light away from said wedges, the other movable mirror reflecting light through said eye piece.