Optical filter and optical system
Assignee3M Innovative Properties Company
InventorsZhaohui Yang, Ryan T. Fabick, Edward J. Kivel
Life of this patent
Estimating the term…
Abstract
An optical filter has an average optical transmission of greater than about 50% in a visible wavelength range (e.g., wavelengths from about 420 nm to about 550 nm) and an optical density greater than about 1.5 in an infrared wavelength range (e.g., wavelengths from about 650 nm to about 800 nm). The optical filter can have a sharp band edge between the visible and infrared ranges. For example, a change in percent transmission of at least about 30% can occur over a wavelength range not greater than about 10 nm wide and/or the slope of the band edge can be greater than about 5%/nm. An optical system includes the optical filter disposed between an emissive display and an optical sensor.
Claims2
An optical system comprising:
- an emissive display configured to emit a visible image in a visible wavelength range extending at least from about 420 nm to about 550 nm;
- an optical sensor configured to receive and sense through the emissive display a first visible light in the visible wavelength range and a second infrared light in an infrared wavelength range extending at least from about 650 nm to about 800 nm;
- and
- an optical filter disposed between the emissive display and the optical sensor, such that for substantially normally incident light, the optical filter has a first band edge between the visible and infrared wavelength ranges such that an optical transmission of the optical filter decreases from about 70% of an average optical transmittance of the optical filter in the visible wavelength range to about 20% of the average optical transmittance of the optical filter in the visible wavelength range with a slope greater than about 5%/nm.
Dependencies are inferred from the claim text.