Patexia seeks prior art for US Patents  6,175,347 (‘347) - “Liquid crystal display apparatus” and 6,421,092 (‘092) - “Automatic picture display position adjusting circuit and picture display apparatus using the same.”

The ‘347 patent allegedly describes a liquid crystal display (LCD) apparatus, comprised of A/D converters, a PLL circuit, a scan conversion circuit, counters, an OR circuit, flip-flops, and a CPU, whereby the location and the size of the picture displayed on the LCD can be automatically adjusted.  The ‘092 patent allegedly describes a picture display positioning circuit and a display device, comprised of a microcomputer and a pixel quantity converter, whereby a picture to just fit the effective picture display area of the picture display device is automatically displayed.

Automatic adjustment of picture location and size, as described by ‘347, takes place by following these steps (Figure 1):

• RBG signals undergo A/D conversion and a scan conversion (when necessary).
• These RGB signals are compared with the phase of an enable signal which indicates a display period of the LCD display.
• A comparison result is generated and the scan conversion rate, the phase of the enable signal, and the vertical and/or horizontal scan conversion ratios are changed in response.
• The picture size, location, and the conversion rate is then automatically adjusted.  This conversion is done in the scan conversion circuit, and can be most broadly read as either a change in sampling frequency, or a scaling process.

Figure 1: Automatically adjusting picture size and location on an LCD

Automatic adjustment of picture display position, as described by ‘092, takes place following these steps (Figure 2):

• Sync signals are separated from the original video signal into at least one horizontal signal and at least one vertical signal.
• In response to variations in sync timing a conversion factor is calculated and transmitted to a pixel quantity converter.
• The video signal is modified by the pixel quantity converter so that a picture corresponding to the modified video signal appears at a desired display position.
• A recalculation is performed in order to shift the display position to the desired display position and the modified video signal is outputted at this desired display position.

Figure 2: Automatic adjusting picture display position