Multi-focus optical device

An optical scanning sensor device comprising:

• an optical semiconductor light source having an output wavelength dependent upon a drive current;
• a diffractive condenser lens to diffract light emitted by said optical semiconductor light source, said lens comprising an unevenly spaced diffraction lattice, said lens directing light toward said object;
• a photodetector unit to receive said light from said object;
• a processing unit to process signals from said photodetector unit;
• a drive circuit to vary said drive current;
• and
• a scanning unit to scan said light diffracted by said refractive condenser lens.

An optical sensor device comprising:

• a light source having an adjustable output responsive to a control circuit, said control circuit adjusting the wavelength of light energy emitted by said light source;
• a lens receiving said light energy emitted by said light source, said lens having an output directing received light energy toward an object to be sensed and having a significantly different focal length received thereby providing a different resolution of detection at each said wavelength received by said lens;
• and
• a detector for receiving light energy from said object to be sensed.

A method of optically sensing an object, said method comprising the steps of:

• directing a wavelength adjustable light source to a lens, said lens having significantly different focal length for each wavelength emitted from said light source;
• directing light from said lens toward an object;
• adjusting the wavelength emitted to change the focal length;
• and
• detecting light.