Camera auto-focusing system with designator using a volume holographic element

Apparatus for use with an imaging optical system;

• said apparatus comprising:
• a laser designator for issuing a beam of radiation in a narrow spectrum of wavelengths;
• a radiation detector sensitive to radiation including said narrow spectrum;
• a diffractive optical element for filtering radiation primarily in said narrow spectrum and focusing said narrow spectrum of filtered radiation on said detector;
• and,
• means for providing a signal indicative of proper focus of the optical system based at least in part on properties of said narrow spectrum of radiation sensed by said detector.

A camera comprising:

• means defining an image plane;
• an optical system forming an image by focusing a broad wavelength spectrum of radiation onto the image plane;
• a mechanism including a radiation detector for setting a camera parameter based on selected properties of at least a portion of said radiation;
• and,
• a radiation deflecting element between said optical system and the image plane, said element transmitting most of the broad wavelength spectrum to form the image and deflecting a narrow wavelength spectrum of said radiation into a path leading to said detector.

Apparatus for setting proper focus in a broad-spectrum imaging optical system;

• said apparatus comprising:
• a designator issuing a beam of radiation in a narrow spectrum for pointing to an object to be imaged by said broad spectrum optical system;
• a radiation detector sensitive to radiation including said narrow spectrum;
• a diffractive optical element for filtering radiation primarily in said narrow spectrum and focusing said narrow spectrum of radiation centered on said detector;
• and,
• means for providing a signal indicative of the proper focus of the optical system based at least in part on the intensity of said narrow spectrum of radiation on said detector.

A photographic camera comprising:

• means for supporting a recording medium in an image plane;
• an optical system having an optical axis and for focusing a broad spectrum of visible radiation on the recording medium in the image plane;
• a narrow spectrum designator for issuing a beam of radiation in a narrow spectrum substantially parallel to the optical axis;
• a focusing mechanism including a detector sensitive to said narrow spectrum for setting camera focus based on the intensity of radiation from said designator reflected by the object;
• and,
• a holographic element between said optical system and the image plane, said element transmitting most of said broad spectrum of radiation to form the image and reflecting said narrow-spectrum of said radiation into a path leading to said detector.

A photographic camera comprising:

• a film plane including means for supporting photographic film;
• an optical system for focusing a broad spectrum of visible radiation onto the film in the image plane, said optical system having an optical axis;
• a narrow spectrum designator for issuing a beam of visible radiation approximately parallel to the optical axis for pointing the system at an object;
• first and second detectors each sensitive to said narrow spectrum;
• holographic means between said optical system and the image plane, said holographic means transmitting most of said broad spectrum of radiation to form the image and reflecting said narrow-spectrum of said radiation into paths leading to said first and second detectors;
• and,
• a focusing mechanism including means for focusing said optical system based on the relative intensity of the radiation on said first and second detectors, respectively.

A photographic camera having an adjustable focus;

• said camera comprising:
• a designator for projecting a beam of visible radiation onto a designated subject, said beam including wavelengths and having an intensity suitable for pointing the camera in daylight;
• an intensity detector sensitive to the designator beam wavelengths and configured to receive radiation reflected from the designated subject;
• and,
• a focusing mechanism including means for isolating and using the detected intensity of the reflected designator beam for adjusting the camera focus.

A photographic camera having an adjustable focus;

• said camera comprising:
• a designator for projecting a beam of visible radiation onto a designated subject, said beam including wavelengths and having an intensity suitable for pointing the camera in daylight;
• first and second photodetectors sensitive to the designator beam wavelengths for providing first and second output signals, respectively, representing the intensity of radiation in said wavelengths on said first and second detectors;
• means for directing radiation reflected from the subject into first and second paths, and for focusing said reflected radiation in front of said first photodetector in said first path and behind said second photodetector in said second path;
• and,
• a focusing mechanism using the difference in the first and second output signals for adjusting the camera focus.

A method of providing a signal for focusing on a subject a camera optical system:

• said method comprising:
• directing a pulsed beam of optical energy in a narrow band of wavelengths at the subject;
• sensing the energy reflected by the subject in said narrow band and producing an electrical signal proportional to the sensed energy;
• integrating said electrical signal in a plurality of time segments synchronized to the pulses of said energy beam;
• providing an output signal for focusing the optical system, said output signal depending on said integration of said electrical signal.

A method of providing a signal for focusing on a subject a camera optical system:

• said method comprising:
• directing a pulsed beam of optical energy in a narrow band of wavelengths at the subject;
• focusing energy reflected by the subject into first and second paths having different focal lengths;
• sensing the reflected energy in said first and second paths and producing first and second electrical signals, respectively, proportional to the sensed energy in said first and second paths;
• integrating said first and second electrical signals over a plurality of time segments synchronized to the pulses of said energy beam:
• providing an output signal for focusing the optical system, said output signal depending on the difference between the integrated first and second electrical signals.

Apparatus for providing a camera focusing signal;

• said apparatus comprising:
• an emitter of modulated optical energy;
• a photodetector for sensing the energy reflected by the subject and producing an electrical signal proportional to the sensed energy;
• a gated integrating circuit for integrating said electrical signal in a plurality of spaced time segments synchronized to the modulation of said optical energy, and;
• means providing an output signal for focusing, said output signal depending on said integrated electrical signal.

Apparatus providing a signal for focusing on a subject a camera optical system:

• said apparatus comprising:
• means for directing pulses of optical energy at the subject;
• means for focusing the optical energy reflected by the subject into first and second paths having different focal lengths;
• first and second photodetectors in said first and second paths, respectively, for producing first and second electrical signals proportional to the reflected energy in said first and second paths;
• a gated integrating circuit for integrating said first and second electrical signals over a plurality of time segments synchronized to the pulses of said optical energy;
• and,
• means providing an output signal for focusing the optical system, said output signal depending on the difference between the integrated first and second electrical signals.