3D lens with reduced back reflectance

A method of making a lens for 3D glasses with reduced back reflectance having an optical interference filter deposited on one or both sides thereof, comprising:

• creating a computer model of a 3D optical interference filter comprising a basic stack of non-absorbing thin film layers necessary to achieve the desired 3D filter optical performance and an appended stack of thin film layers, incorporating one or more substantially absorbing thin film layers in the form of metal or semiconductor effective to reduce back reflectance, placed adjacent to the said basic stack, with the total stack of layers having substantial transmittance at one or more passbands over the visible spectral range in order to view a desired left or right eye image, and a substantial reflectance and absorption at one or more different blocking bands over the visible spectral range in order to block the undesired right or left eye image;
• varying in said computer model at least one variable selected from the group consisting of the material, thickness and number of said thin film layers to ensure at least one of said passbands has a (relative change in transmittance/(relative change in luminance back reflectance) ratio less than about 0.5, where the relative change is with respect to the transmittance and luminance back reflectance performance based on the said previous stack of non-absorbing layers;
• and
• depositing said absorbing and non-absorbing layers on a lens substrate in accordance with said computer model.

A lens for 3D glasses with reduced back reflectance having an optical interference filter deposited on one or both sides thereof, said optical interference filter comprising:

• a basic stack of non-absorbing thin film layers based on a filter design without reduced back reflection, the number, materials and thicknesses of said thin film layers being selected such that the 3D optical interference filter has substantial transmittance at one or more passbands over the visible spectral range in order to view a desired left or right eye image, and
• a substantial reflectance and absorption at one or more different blocking bands over the visible spectral range in order to block the undesired right or left eye image, characterized in that said optical interference filter further comprises:
• an appended stack of at least three layers incorporating one or more absorbing layers in the form of thin film metal or semiconductor layers effective to reduce back reflectance;
• and
• wherein the (relative change in transmittance)/(relative change in luminance back reflectance) ratio for at least one of said passbands is less than about 0.5, where the relative change is with respect to the transmittance and luminance back reflectance performance based on setting the thicknesses of said one or more absorbing layers to 0 nm.