Abstract: A method of surface hardening titanium orthopedic implant devices, and a titanium orthopedic implant device prepared by the disclosed method. An orthopedic implant device made of pure titanium or a titanium alloy, such as Ti-6Al-4V (ELI) is exposed to molecular nitrogen gas at a process temperature and for a process time duration sufficient to enhance surface hardness and wear resistance properties, without the formation of a measurable TiN layer that tends to increase surface roughness and diminish wear resistance properties. The process temperature is in the range of 750.degree. F. to 1300.degree. F., preferably about 1100.degree. F. and the process time duration at the preferred process temperature is approximately 8 hours. The hardened surface of the titanium implant occurs primarily due to solid solution hardening of the titanium with nitrogen by dissolution.

Abstract: A method of surface hardening cobalt-chromium based orthopedic implant devices, and a cobalt-chromium orthopedic implant device prepared by the disclosed method. An orthopedic implant device made of a cobalt-chromium or cobalt-chromium-molybdenum alloy, such as ASTM F-75 or ASTM F-799 is exposed to molecular nitrogen gas or ionized nitrogen at a process temperature and for a process time duration sufficient to enhance surface hardness and wear resistance properties, without the formation of a measurable nitrogen layer that tends to increase surface roughness and brittleness and diminish wear resistance properties. The process temperature is in the range of 500.degree. F. to 2400.degree. F., preferably about 1400.degree. F., and the process time duration at the preferred process temperature is approximately 48 hours.

Abstract: A method of surface hardening titanium orthopedic implant devices, and a titanium orthopedic implant device prepared by the disclosed method. An orthopedic implant device made of pure titanium or a titanium alloy, such as Ti-6Al-4V (ELI) is exposed to molecular nitrogen gas at a process temperature and for a process time duration sufficient to enhance surface hardness and wear resistance properties, without the formation of a measurable TiN layer that tends to increase surface roughness and diminish wear resistance properties. The process temperature is in the range of 750.degree. F. to 1300.degree. F., preferably about 1100.degree. F. and the process time duration at the preferred process temperature is approximately 8 hours. The hardened surface of the titanium implant occurs primarily due to solid solution hardening of the titanium with nitrogen by dissolution.

Abstract: A narrow-band interference filter is placed in the path of reflected opti energy for rejecting undesirable signals to thereby improve the signal-to-noise ratio. The interference filter functions as a bandpass filter having a center frequency centered around the frequency of the transmitted optical beam. The filter includes four identical quarter annulus sections, each composed of a mosaic of interference filter elements cemented to a glass substrate. Each substrate is itself positioned within a skeletal spider structure to provide the desired shape and rigidity.