APPARATUS FOR GENERATING HIGH CONTRAST OPTICAL SIGNALS, AND EXEMPLARY APPLICATIONS

摘要

A display apparatus generates a high visibility optical signal, such as an ICON, the ICON comprising a symbol, shape, or other image-like representation. The ICON becomes visible at an observation point during an illumination ON-state. The ICON may be formed as a portion of display medium, for example as a machined portion of a mirror capable of forming images of a scene by reflection in normal operation. The visibility of the ICON in the illumination OFF-state from an observation point is sufficiently low such that the normal operation of the display medium is maintained. The display apparatus may be used in a blind spot warning system for a vehicle. Visible wavelength LEDs, RGB LEDs and/or diode lasers may be utilized as an illumination source. Ultrashort laser processing or other methods for material modification may be utilized to form microscopic features which distribute incident light, increasing the visibility of the optical signal at an observation point in an ON-state, with very low visibility in the OFF-state and minimal effect on the image in the display medium in the OFF state.

主权项

1. A laser-based method, comprising: irradiating a portion of an optical medium with laser pulses, said irradiating removing at least a depth-wise portion of material from a region of said medium, and forming a predetermined pattern of microscopic features arranged in such a way that a detectable optical signal is visible therefrom with illumination from a first source, said medium capable of receiving illumination from a second source, and wherein said region of said medium is essentially indistinguishable from other parts of the medium without illumination from said first source, wherein said region of said optical medium comprises microscopic features formed in said medium, said microscopic features having a size in the range from about 0.5 μm to about 100 μm, increasing the visibility of said optical signal by said forming step causing said microscopic features to be substantially absent of any melted or oxidized region there along, and wherein said forming step forms said microscopic features with ultrashort laser pulses.