Polarizing plate

Abstract

The invention provides a polarizing plate applied to a liquid crystal display. The polarizing plate comprises a polarizing layer, a quantum rod layer, a first protecting layer and a second protecting layer, wherein the polarizing layer is provided with an absorbing shaft; the quantum rod layer is arranged on the surface of the polarizing layer and provided with a plurality of quantum bars; the long shafts of the plurality of quantum rods are arranged in the direction vertical to the absorbing shaft of the polarizing layer and is parallel to a transmission shaft of the polarizing layer; the first protecting layer is arranged at one side of the polarizing layer, opposite to the quantum rod layer; the second protecting layer is arranged at one side of the quantum rod layer, opposite to the polarizing layer. 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 can be 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 what is emitted by the ba...

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 backlight output is left, and the utilization rate of the backlight is quite low, resulting in a waste of energy.

[0003] However, there are many methods to increase the efficiency of the backlight source have been proposed, such as adding brightness-enhancing film, prism sheet, etc. to 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 alignment direction of the long axis of the quantum rod, the polarized light excited by it can easily pass through the polarizer on the liquid crystal panel The penetration axis, so compared to the non-polarized backlight without adding the quantum rod layer, the utilization rate of the light source can be increased theoretically, but usually the semiconductor material of this type of quantum rod is easily affected by the water and oxygen in the environment and the service life is reduced. 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, and the current display If the heat generated by the backlight is not properly designed for heat dissipation or the heat insulation structure is added, the thermal decay of the quantum rods will also reduce the fluorescence efficiency, and the light emitted by the backlight needs to pass through the backlight module in the path through which the light passes to the panel. If the optical films such as light guide film, diffusion film, brightness enhancement film, multi-group prism sheet and polarizer outer protective film in the group are arranged in the optical film layer structure of the backlight module, the excited After the converted polarized light source is repeatedly refracted and reflected between the optical films, the degree of polarization and directionality of the polarized light source parallel to the transmission axis of the polarizer will also be greatly reduced, reducing the progress of the lower polarizer that can actually pass through the panel. 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 transmittance of the backlight through the quantum rod layer is excellent. 50% passes through a single polarizing plate, but because the quantum rods have a long axis and a short axis, although the long axis direction can be excited by the backlight to polarize light, and the short axis direction also partially penetrates the light component, therefore, the quantum rod layer It is impossible to achieve the polarization degree of more than 99% of 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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