| 摘要 |
<p>A wavelength-selective pad (10) that is transparent when viewed by light of a first wavelength μ1 (e.g., visible light) and is highly reflective when viewed by light of a second wavelength μ2 (e.g., infrared light). The pad (10) has a grid (15) positioned above the highly reflecting layer so that this grid (15) can be sensed by use of light of wavelength μ2 while, simultaneously, images, graphics or text positioned below the pad may be read by use of light of wavelength μ1. A text scanner system (31) that produces and senses light at the two wavelengths is used in combination with the pad (10) to simultaneously read the graphics or text and the grid position of the beam that illuminates the graphics and text.</p> |
