Remote focusing override mechanism for an automatic focusing photographic projector

Claim 2

In a projector having a housing, an illuminated optical axis, means for supporting film transparencies along said optical axis, a support member mounted on said housing for movement in a direction parallel to said optical axis, automatic focusing means for sensing the distance along said optical axis between a supported film transparency and said support member and for generating an error signal indicative of any variation of said distance from a predetermined reference distance, and a projection lens adjustably mounted on said support member for movement therewith along said optical axis; the improvement comprising: a single drive member engageable to move said projection lens along said optical axis; means for frictionally coupling said drive means to said support member to move said support member in a direction parallel to said optical axis; means selectively actuatable for preventing movement of said support member; means responsive to an error signal from said automatic focusing means for energizing said drive member; and means for disabling said energizing means when said means for preventing movement of said support member is actuated.

Claim 3

The improvement as defined in claim 1 wherein said means for preventing movement of said support member comprises a mechanism for engaging said support member to prevent movement thereof by said drive member.

Claim 4

The improvement as defined in claim 2 wherein said mechanism comprises an electromagnet.

Claim 5

The improvement as defined in claim 2 wherein said mechanism comprises: a brake disc: a solenoid; and Cam means interposed between said brake disc and said solenoid and responsive to energization of said solenoid to move said brake disc into braking engagement with said support member.

Claim 6

In film image projection apparatus for automatically maintaining a predetermined distance between a film which is capable of displacement along the optical axis of the apparatus and a projection lens, the combination comprising: film scanning means including movable optical means and a radiation source for projecting radiation onto the film; means responsive to reflected radiation from the film for sensing variations in the distance between the film and the projection lens from a predetermined distance resulting from film displacement along the optical axis and for generating an output signal corresponding to the film displacement; drive means coupled to said movable optical means and the projection lens and responsive to said output signal for moving both said optical means and said projection lens to restore the distance between the film image and the projection lens to said predetermined distance; control means for operating said drive means; and means responsive to said control means for disabling said sensing means, arresting movement of said optical means, and operating said drive means for moving only said projection lens independently of said movable optical means to adjust said predetermined distance to place the projected film image in optimum focus.

Claim 7

In film image projection apparatus for automatically maintaining a predetermined distance between a film which is capable of displacement along the optical axis of the apparatus and a projection lens, the combination comprising: film scanning means including movable optical means and a radiation source for projecting radiation onto the film; means responsive to reflected radiation from the film for sensing variations in the distance between the film and the projection lens from a predetermined distance resulting from film displacement along the optical axis and for generating an output signal corresponding to the film displacement; drive means coupled to said movable optical means and the projection lens and responsive to said output signal for moving both said optical means and said projection lens to restore the distance between the film image and the projection lens to said predetermined distance; control means for operating said drive means; and means responsive to said control means for disabling said sensing means, arresting movement of said optical means, and operating said drive means for moving only said projection lens independently of said movable optical means to adjust said predetermined distance to place the projected film image in optimum focus.

Claim 8

In apparatus for automatically focusing the projected film image of a projector to compensate for film displacement from a film plane during projection wherein the film image is illuminated by a light source and is projected by a projection lens displaced a predetermined distance from the film onto a viewing plane, the combination compriSing: radiation means for scanning the film and including movable optical means for directing radiation onto the film; means responsive to the radiation reflected from the film for sensing variations in the distance between said lens and said film plane from the predetermined distance resulting from film displacement from said film plane and for generating an output signal corresponding to the film displacement, said sensing means having a null condition in which said output signal is at a predetermined magnitude and the distance between said film image and said projection lens is maintained at said predetermined distance; automatic means responsive to said output signal of said sensing means when film displacement occurs for simultaneously moving both said projection lens and said optical means until said sensing means returns to its null condition; and means for disabling sensing means, arresting said automatic means, and moving only said projection lens to focus the film image on the viewing plane in those situations where the film image is out of focus in the null condition of said sensing means.

Claim 9

In apparatus for automatically focusing the projected film image of a projector to compensate for film displacement from a film plane during projection wherein the film image is illuminated by a light source and is projected by a projection lens displaced a predetermined distance from the film onto a viewing plane, the combination compriSing: radiation means for scanning the film and including movable optical means for directing radiation onto the film; means responsive to the radiation reflected from the film for sensing variations in the distance between said lens and said film plane from the predetermined distance resulting from film displacement from said film plane and for generating an output signal corresponding to the film displacement, said sensing means having a null condition in which said output signal is at a predetermined magnitude and the distance between said film image and said projection lens is maintained at said predetermined distance; automatic means responsive to said output signal of said sensing means when film displacement occurs for simultaneously moving both said projection lens and said optical means until said sensing means returns to its null condition; and means for disabling sensing means, arresting said automatic means, and moving only said projection lens to focus the film image on the viewing plane in those situations where the film image is out of focus in the null condition of said sensing means.

Claim 10

In a photographic projector having means for holding a film containing an image area in a film plane, said film being capable of shifting out of coincidence with said film plane, a light source for illuminating the image area of said film, and a projection lens positioned a predetermined distance from said image area for projecting the image area onto a screen or the like, the combination comprising: a radiation source; first means movably mounted adjacent said radiation source, said first means including optical means to form an image of said radiation source on the film; sensing means for generating an output signal in response to radiation; second means to reimage the reflected image of said radiation source from the film onto said sensing means, said sensing means generating said output as a function of the position of the reimage thereon and having a minimum output at a null position of the reimage at which the distance between the film and said projection lens is the predetermined distance; third means responsive to said output from said sensing means when the film is shifted and the position of the reimage is altered from its null position to move both said projection lens and said optical means until the reimage is restored to its null position; control means for operating said third means; and means responsive to said control means for in timed relation (1) disabling said sensing means, (2) arresting movement of said optical means in the position assumed by said optical means when said sensing means is in said null condition, and (3) moving only said projection lens to adjust the predetermined distance and to place the projected image area in optimum focus.

Claim 11

In a photographic projector having means for holding a film containing an image area in a film plane, said film being capable of shifting out of coincidence with said film plane, a light source for illuminating the image area of said film, and a projection lens positioned a predetermined distance from said image area for projecting the image area onto a screen or the like, the combination comprising: a radiation source; first means movably mounted adjacent said radiation source, said first means including optical means to form an image of said radiation source on the film; sensing means for generating an output signal in response to radiation; second means to reimage the reflected image of said radiation source from the film onto said sensing means, said sensing means generating said output as a function of the position of the reimage thereon and having a minimum output at a null position of the reimage at which the distance between the film and said projection lens is the predetermined distance; third means responsive to said output from said sensing means when the film is shifted and the position of the reimage is altered from its null position to move both said projection lens and said optical means until the reimage is restored to its null position; control means for operating said third means; and means responsive to said control means for in timed relation (1) disabling said sensing means, (2) arresting movement of said optical means in the position assumed by said optical means when said sensing means is in said null condition, and (3) moving only said projection lens to adjust the predetermined distance and to place the projected image area in optimum focus.

Claim 12

The invention according to claim 7 wherein: said first means comprises a movable member; said third means comprises a motor and means drivingly connecting said motor to said movable member and to said projection lens; and said disabling, arresting and operating means comprises a mechanism for engaging said movable member to prevent movement thereof by said motor.

Claim 13

In a projector having a housing, an illuminated optical axis, means for supporting film transparencies along said optical axis, a support member mounted on said housing for movement in a direction parallel to said optical axis, automatic focusing means for sensing the distance along said optical axis between a supported film transparency and said support member and for generating an error signal indicative of any variation of said distance from a predetermined reference distance, and a projection lens adjustably mounted on said support member for movement therewith along said optical axis; the improvement comprising: coupling means actuable to a first condition for drivingly connecting said drive member to said support member and said projection lens for mOving both said support member and said projection lens in unison and to a second condition for drivingly connecting said drive member to said projection lens for moving said projection lens relative to said support member; means responsive to an error signal from said automatic focusing means for energizing said drive member when said coupling means is in said first condition; and separate means for energizing said drive member when said coupling means is in said second condition.

Claim 14

In a projector having a housing, an illuminated optical axis, means for supporting film transparencies along said optical axis, a support member mounted on said housing for movement in a direction parallel to said optical axis, automatic focusing means for sensing the distance along said optical axis between a supported film transparency and said support member and for generating an error signal indicative of any variation of said distance from a predetermined reference distance, and a projection lens adjustably mounted on said support member for movement therewith along said optical axis; the improvement comprising: coupling means actuable to a first condition for drivingly connecting said drive member to said support member and said projection lens for mOving both said support member and said projection lens in unison and to a second condition for drivingly connecting said drive member to said projection lens for moving said projection lens relative to said support member; means responsive to an error signal from said automatic focusing means for energizing said drive member when said coupling means is in said first condition; and separate means for energizing said drive member when said coupling means is in said second condition.