Color balance

We have just described the basic operating principles of some main transflective LCDs. The simulation results are based on some ideal assumptions. It is understandable that many other factors can affect the display image qualities, such as color balance, image brightness, and viewing angle. 

Because the reflection beam passes through the color filter (CF) twice, while the transmission beam only passes once, generally speaking, the transflective LCD experiences an unbalanced color between the T- and R-modes. To solve the color imbalance problem, different CF approaches have been developed. Sharp Corp. proposed a multi-thickness color filter 

In addition to the MT-CF design, a pinhole type CF design was also proposed by Sharp. There, the thicknesses of the CF in the two regions are equal, but the CF in the reflection region is punched with some pinholes. Therefore, a portion of the ambient light does not see the CF instead, it passes through the pinholes directly. The problem of such a pinhole type CF is its narrow color reproduction area because the ambient hght spectmm is mixed with the RGB primary colors, which causes the color impurity. 

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In color technology and measurement, both types of approaches are used. Color printing, for example, generally employs three colors (usually plus black), and the ever useful CIE system was founded on experiments in which colors were matched by mixtures of three primary colors, often blue, green, and red. Yet transmitted television signals are based on the opponent system, with one intensity and two color-balance signals, as are the modern representations of color, such as the CIELAB and related color spaces based on red-green and yeUow-blue opponent axes. 

Donor and acceptor levels are the active centers in most phosphors, as in zinc sulfide [1314-98-3] ZnS, containing an activator such as Cu and various co-activators. Phosphors are coated onto the inside of fluorescent lamps to convert the intense ultraviolet and blue from the mercury emissions into lower energy light to provide a color balance closer to daylight as in Figure 11. Phosphors can also be stimulated directly by electricity as in the Destriau effect in electroluminescent panels and by an electron beam as in the cathodoluminescence used in television and cathode ray display tubes and in (usually blue) vacuum-fluorescence alphanumeric displays. 

The perceived color stabiUty of a photographic system is usually limited by the fa ding of its least stable dye, which can produce an undesirable shift in color balance. Whereas recovery of such faded images is often possible, a so-called neutral fade, in which all three color records lose density at approximately the same rate, is usually preferred. 

Preproduction dye developer negatives used a combination of cellulose acetate and cellulose acetate hydrogen phthalate as barrier layers. The images produced from these negatives were outstanding in color isolation, color saturation, and overall color balance. However, solvent coating was requited with this composition, and it was not used in production. 

In the fluorescence microscope, careful consideration of the sample and system components is necessary to specify the correct filters for probe detection. Use of multiband dichroics and emission filters in a stationary turret with single exciters in an external slider or filter wheel can give near simultaneous probe detection with no registration shift, but there are likely compromises in overall brightness, color balance difficulty, and reduced resolution of the color CCD camera. 

Features Low m.w. thermoplastic offers It. color, balance of tack, adhesive, and cohesive props., heat resistance, and wide compat. and sol. avail, in two stabilized grades (BBHT and BHM)... 

Manipulation often includes picture editing and color balancing before putting the image into repeat, or fitting the image to a particular size or shape for a placement print. Placement prints are similar to those seen on the front of T-shirts but are not limited to this format... 

Color photomicrographs have variable color balance and brighmess. 

This may be done with color overlay systems, which offer a quick assessment. These were the first color proofing systems—precolored films, which could be exposed to corresponding color separation films and developed in a solvent to give appropriately colored proofs. By superimposing four colored transparencies in register the printer could check color balance and other quality control parameters. 

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