Patent ID: 8860909

Claim:
A transparent display device, comprising: a liquid crystal display panel; a light source disposed at one side of a lower portion of the liquid crystal display panel to emit light; a first polarizing plate for polarizing the light emitted from the light source; a light guide plate having a front surface facing the liquid crystal display panel, and a rear surface opposing to the front surface, and a lateral surface between the front surface and the rear surface, the light guide plate being disposed at a lower portion of the liquid crystal display panel to reflect totally the light polarized in an axis-direction by the first polarizing plate to the lateral surface of the light guide plate and supply to the liquid crystal display panel, and transmit natural light entered from a lower direction therethrough; a plurality of air layers formed inside the light guide plate to reflect totally the incident light; and a second polarizing plate at an upper portion of the liquid crystal display panel to control the amount of polarized light transmitting the liquid crystal display panel, wherein the natural light is incident to the rear surface of the light guide plate from the outer portion of the display device and then supplied directly to the liquid crystal display panel through front surface of the light guide plate without a polarizing state of the light to transmit the liquid crystal display panel in order to display transparently an object at the rear portion of the liquid crystal display panel when a signal is not applied to the liquid crystal panel, and the light polarized by the first polarizing plate is supplied through the lateral surface of the light guide plate to the liquid crystal display panel to display an image according to the inputted signal when the signal is not applied to the liquid crystal panel.