Polarizing plate

Abstract

The invention relates to a polarizing plate applied to a liquid crystal display. The polarizing plate comprises a polarizing layer, a first protecting layer and a second protecting layer, wherein the first protecting layer is arranged on one surface of the polarizing layer; the second protecting layer is arranged on the other surface of the polarizing layer; a plurality of quantum rods are arranged in the protecting layer, and long shafts of the plurality of quantum rods are vertical to an absorbing shaft of the polarizing plate. According to the polarizing plate, unpolarized incident light emitted by a backlight source enters the polarizing plate and is converted by the quantum rods into polarized light and then directly flows through the polarizing layer, and therefore, the utilization rate of the backlight source can be increased.

Description

technical field [0001] The invention relates to a polarizing plate, in particular to an integrated polarizing plate containing quantum rods. The polarizing plate is used in a liquid crystal display, so that the liquid crystal display has better color gamut and light source utilization. Background technique [0002] The polarizer used in conventional liquid crystal displays generally adopts an absorbing polarizer. When the non-polarized light emitted by the backlight passes through the polarizer, the component in the direction of the absorption axis of the polarizer will be absorbed and cannot pass through. Therefore, the transmittance of the polarizer to the backlight source can only reach below 50% theoretically. After the light passes through the electrode layer of the liquid crystal panel, the color filter, the liquid crystal layer and the glass substrate, the user can actually see the display. If the brightness is high, only less than 10% of the light emitted by the back...

AI Technical Summary

Problems solved by technology

[0002] The polarizer used in conventional liquid crystal displays generally adopts an absorbing polarizer. When the non-polarized light emitted by the backlight passes through the polarizer, the component in the direction of the absorption axis of the polarizer will be absorbed and cannot pass through. Therefore, the transmittance of the polarizer to the backlight source can only reach below 50% theoretically. After the light passes through the electrode layer of the liquid crystal panel, the color filter, the liquid crystal layer and the glass substrate, the user can actually see the display. If the brightness is low, only 10% of the light emitted by the backlight is left, and the utilization rate of the backlight is quite low, resulting in a waste of energy.

[0003] And many methods to increase the efficiency of the backlight have been proposed, such as adding brightness-enhancing film, prism sheet, etc. in the backlight module, so that the light that cannot pass through the polarizer is continuously reflected, recycled or concentrated, and then passes through the polarizer to achieve The purpose of brightness enhancement, but in order not to affect the viewing angle, it is often necessary to use a combination of multi-layer brightness enhancement film and prism sheet, which increases the thickness of the backlight module

[0004] In addition, a solution is also proposed, adding a quantum rod layer in the backlight module. The quantum rod is a nano-scale semiconductor material with a one-dimensional shape. The direction of its long axis can absorb unpolarized light and then excite the Biyuan incident light source. Polarized light with a longer wavelength, and because of the high internal quantum efficiency, a large amount of light from the backlight can be converted into polarized light. After adjusting the long-axis alignment direction of the quantum rods, the polarized light excited by the quantum rods can easily pass through the liquid crystal panel. The penetration axis of the polarizing plate, so compared to the non-polarized backlight without adding the quantum rod layer, the utilization rate of the light source can be theoretically increased, but usually the semiconductor material of this type of quantum rod is easily affected by the water and oxygen in the environment and reduces the use Therefore, it is necessary to increase the packaging structure, such as adding a barrier layer on its surface, so the thickness of the backlight module is correspondingly increased; in addition, because the quantum rod layer is arranged in the backlight module, the distance from the backlight is relatively close, the current If the heat generated by the backlight of the display is not properly designed for heat dissipation or the heat insulation structure is added, the quantum rods will also be thermally decayed and the fluorescence efficiency will be reduced, and the light emitted by the backlight needs to pass through the path of the panel. For optical films such as light guide film, diffusion film, brightness enhancement film, multiple groups of prism sheets, and polarizer outer protective film in the backlight module, if the quantum rod layer is arranged in the optical film layer structure of the backlight module, its After the excited and converted polarized light source undergoes multiple refraction and reflections between the optical films, the polarization degree and directionality of the polarized light source parallel to the transmission axis of the polarizer will also be greatly reduced, reducing the actual penetration of the lower polarizer of the panel. In addition, if only a single quantum rod layer is combined with a backlight as a polarized light source, and various optical films or lower polarizers are omitted, the polarization efficiency of the backlight is still not good, because the light transmission of the backlight through the quantum rod layer Although the intensity is better than 50% through a single polarizing plate, because the quantum rod has a long axis and a short axis, although the long axis direction can be excited by the backlight to polarized light, but the short axis direction also partially penetrates the light component. Therefore, The quantum rod layer cannot achieve the polarizing degree of more than 99% as the polarizing plate used in the current liquid crystal display, and the contrast and saturation of the liquid crystal display do not meet the needs of users

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