Abstract: A display apparatus having a viewing angle control unit is provided. The viewing angle control unit may be disposed between a back-light unit and a liquid crystal panel. The viewing angle control unit may include a control liquid crystal layer disposed between a lower electrode and an upper electrode. The viewing angle control unit may be switched to a wide viewing angle mode or a narrow viewing angle mode according to voltage applied to the lower electrode and the upper electrode. In the narrow viewing angle mode, each liquid crystal particle of the control liquid crystal layer may be obliquely arranged with respect to the lower electrode and the upper electrode. Thus, an image provided by the display apparatus may be not recognized to peoples around a user, selectively.

Abstract: The present invention relates to tooth powder containing elvan as a radiation source of a far infrared ray wherein the tooth powder includes 10 weight % to 90 weight % of elvan as a radiation source of a far infrared ray and 10 weight % to 90 weight % of bamboo salt, and is characterized in that the rate of the elvan and the bamboo salt is 10:90 to 90:10. Also, it is of sovereign remedy in preventing teeth from decaying with medicine made by desiccating sap of a lacquer tree.