Light diffusing sheet

Table 7 shows a polycarbonate (PC) resin which was treated with Tospeari to provide an improved light diffusing sheet (9). At only 40% of the barium sulfate level, the Tospeari treated sheet allowed more light through and the light was better dispersed than the conventional additive. The mechanical integrity of the PC sheeting was also retained as shown by the mechanical measurements. 

Applications and uses optical parts, display items, tube and profile extrusion, automotive rear lights and dashboard lenses, extruded sheet, copying equipment and lighting diffusers, UV protective films for exterior laminates. 

G. Park, T. S. Aum and J. H. Kwon, Characterization and modeling light scattering in diffuser sheets,... 

Table 8 also shows a light diffusing application using acrylic sheeting. Again, more light is transmitted and is more diffuse (10). 

Compared to the laser triangulometry technique, the originality of this technique lies in the use of a thin laser sheet instead of a crude laser spot. Consequently, measurements of deposit thickness profiles in the direction transverse to the channel can be obtained, by dividing the channel in several ROIs as explained above. The lateral resolution of this technique is defined by the minimum lateral size of the ROIs that can be used, which is 10 pixels (30 pm with the magnification used in our application). However, it must be noted that it is not possible to obtain an accurate thickness value near the channel wall because of the signal being too noisy, probably due to light diffusion from the wall. 

Like many optical methods, the method presented in this chapter is limited by the concentration of the suspension. Indeed, at large concentration, light diffusion by the suspended particles is going to blur the image of the laser sheet. Thus, for each application there is a maximum concentration that can be used. 

Fig. 13. Single-sheet diffusion transfer plate (a) stmcture (b) upon exposure to light (c) development and (d) washing off and finish. In (a) the plate is first coated with a receiver layer of small (<5 nm) catalytic sites. The photographic layer is a spectrally sensitized silver haUde emulsion. In (c) the exposed areas develop as silver metal. Unexposed areas diffuse down to the receiver layer and form the printing image. In (d) the emulsion is washed off, revealing...

Wrap a sheet of paper around vials 1 and 2 to prevent light from entering the sides of the solutions. Looking down through the vials over a diffuse light source, adjust the volume of the standard solution in vial 1 until the colour intensity in the vials is the same. Use a medicine dropper to remove or add standard solution. Be careful not to add standard solution to vial 2. 

Wire mini-grid OTEs. A mini-grid" is constructed with an array (or mesh ) of microscopically thin wires criss-crossing the face of a sheet of glass, silica or quartz. The wires are themselves too thin to see, but as soon as product is formed, it diffuses away from the wire. Since diffusion is entropy-driven (i.e. random), electrogenerated material does not diffuse in straight lines, but moves in all directions at once. In practice, as soon as material is formed, it is seen between the wires, and hence can be detected by the light beam of a spectrometer. 

Medical grade PVC sheets and tubes were surface modified by nucleophilic substitution of chlorine atoms by photoactive diethyl dithiocarbamate in the presence of a suitable phase transfer catalyst. The modified surface was crosslinked by UV light to create a barrier for the diffusion of plasticiser. The effect of concentration of phase transfer catalyst and diethyl dithiocarbamate, time of reaction and irradiation dose on the extent of plasticiser migration was examined. 26 refs. 

Diffuse reflectance infrared Fourier transform (DRIFT) spectra are obtained when IR radiation is incident on a scattering sample at a specific angle and is reflected at all angles. The diffuse reflectance process involves transmission, scattering, and reflection [67]. The technique is used to analyze an intact lignin sample without modification [65]. To study a sample by DRIFT, the sample is either dispersed in KBr (e.g., MWL) or is analyzed directly (e.g., paper sheet) and placed at the focal point of the diffuse reflectance accessory. The scattered light from the sample is collected... 

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