KR100552909B1 - Liquid crystal display device - Google Patents

Abstract

The present invention relates to a liquid crystal display device capable of improving image quality by preventing a change in physical properties of the liquid crystal and poor gravity.

The present invention provides a liquid crystal panel including an upper substrate having an upper array and a lower substrate having a lower array, a polarizer disposed under the liquid crystal panel, and a backlight positioned under the polarizer to scan light to the liquid crystal display panel. In the liquid crystal display comprising a, wherein at least one of the lower substrate and the polarizing plate includes a rare earth particles having an infrared blocking function is characterized in that the infrared rays from the backlight is selectively blocked by the rare earth particles. .

Description

Liquid crystal display {LIQUID CRYSTAL DISPLAY DEVICE}             

1 is a cross-sectional view showing a liquid crystal display module of a conventional liquid crystal display device.

2A to 2D are diagrams showing experimental results and the like for explaining problems caused by changes in physical properties of liquid crystals.

3 is a cross-sectional view showing a liquid crystal display module of the liquid crystal display device according to the present invention.

4 is a view showing in detail the polarizing plate according to the present invention.

<Description of Symbols for Main Parts of Drawings>

2, 102: liquid crystal panel 16, 116: lamp housing

20, 120: lamp 24, 124: light guide plate

26, 126: reflector plate 30, 130: diffusion sheet

40, 140: lower polarizer 42, 142: upper polarizer

150: rare earth nanoparticles

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device capable of improving image quality by preventing liquid crystal properties and gravity failure.

A typical liquid crystal display device is composed of a liquid crystal display module (hereinafter referred to as "LCM"), a driving circuit portion and a case for driving this LCM.

The LCM is composed of a liquid crystal display panel in which liquid crystal cells are arranged in a matrix form between two substrates, and a backlight unit for irradiating light to the liquid crystal display panel. In addition, in the LCM, optical sheets for vertically raising the light traveling from the backlight unit toward the liquid crystal panel are arranged. The liquid crystal panel, the backlight unit, and the optical sheet are fastened in an integrated form to prevent light loss, and a case is used to surround and protect the outside of the LCM to prevent damage to the LCM due to external impact.

The LCM is used to be mounted on a notebook personal computer, a mobile vehicle, an aircraft, and the like, which is manufactured in a size of a notebook so that a user can use information between mobiles.

1 is a cross-sectional view briefly showing a conventional LCM.

The LCM shown in FIG. 1 includes a liquid crystal panel 2 having a liquid crystal cell matrix, upper and lower polarizers 42 and 40 positioned on the front and rear surfaces of the liquid crystal panel 2, and a liquid crystal under the lower polarizer 40, respectively. The backlight unit irradiating light to the display panel is positioned.

The liquid crystal panel 2 includes a lower array substrate (or thin film transistor array substrate) 2a and an upper array substrate (or color filter array substrate) 2b that are bonded to each other with the liquid crystal interposed therebetween. The lower array array substrate 2a is composed of signal lines and thin film transistors formed on the lower substrate, and the upper array substrate 2b is composed of color filters and black matrices formed on the upper substrate.

The lower polarizer 40 is attached to the rear surface of the lower array substrate 2a and polarizes the light beam emitted from the backlight unit, and the upper polarizer 42 is attached to the front surface of the upper array substrate 2b so that the liquid crystal panel 2 It serves to polarize the emitted light beam.

The backlight unit includes a lamp 20 for generating light, a lamp housing 10 installed to surround the lamp 20, a light guide plate 24 for converting light incident from the lamp 20 into a planar light source, and And a reflecting plate 26 provided on the rear surface of the light guide plate 24 and diffusion sheets 30 sequentially stacked on the light guide plate 24.

The light guide plate 24 guides the light beam generated from the light source toward the liquid crystal panel 2.

The upper and lower diffusion sheets 30 may propagate the light beam guided by the light guide plate 24 in the vertical direction to the front surface.

On the other hand, in addition to the light guide plate method using the light guide plate 24 described above, the backlight of the direct type method that can improve the brightness by placing a plurality of fluorescent lamps may be used.

As described above, in the conventional liquid crystal display device, whether the liquid crystal is expanded by heat of light of the backlight, such as a light guide plate method or a direct type method, a change in physical properties of the liquid crystal occurs, thereby causing a problem of poor gravity and deterioration in image quality.

This will be described in detail with reference to FIGS. 2A to 2D.

In general, the physical properties of the liquid crystal have properties as shown in Table 1.

Liquid crystal Room temperature (20-25 degrees) 50-60 Dielectric anisotropy (△ ε) 7 4.1 Refractive index anisotropy (△ n) 0.1779 0.0581

When the liquid crystal is exposed to a high temperature environment, the values of the dielectric anisotropy (Δε) and the refractive index anisotropy (Δε) are changed so that the liquid crystal transmittance {T 에서 Δ n * d (d: cell gap)} of the light emitted from the backlight is decreased. do.

2A, it can be seen that as the electric field is applied to the liquid crystal, the transmittance of the liquid crystal in the environment A of 60 degrees is lower than that of the liquid crystal in the environment B of 20 degrees. As the temperature increases, the transmittance decreases. As shown in FIG. 2B, the luminance decreases and the image quality of the liquid crystal display panel decreases.

In addition, since the liquid crystal expands in a high temperature environment, as shown in FIG. 2C, the cell gap of the liquid crystal panel is increased so that the spacer 22 falls off the upper substrate 1 or the lower substrate 21 and the expanded liquid crystal ( 8) is overfilled in the direction of gravity to cause a gravity failure that causes deformation of at least one of the upper substrate 1 and the lower substrate 21, so that a stain or the like appears on the lower portion of the liquid crystal panel as shown in FIG. 2D. .

As such, the physical properties of the liquid crystal are changed by the backlight light, thereby causing a decrease in luminance and transmittance, thereby causing a problem of deterioration in image quality.

Accordingly, it is an object of the present invention to provide a liquid crystal display device capable of improving image quality by preventing a change in physical properties of the liquid crystal and a poor gravity.

In order to achieve the above object, the present invention provides a liquid crystal panel including an upper substrate on which an upper array is formed and a lower substrate on which a lower array is formed, a polarizing plate disposed below the liquid crystal panel, and a liquid crystal display disposed below the polarizing plate. A liquid crystal display device comprising a backlight for scanning light onto a panel, wherein at least one of the lower substrate and the polarizer includes rare earth particles having an infrared blocking function such that infrared light from the backlight is selected by the rare earth particles. Characterized in that blocked.

The backlight may include a light guide plate, and the light guide plate may include the rare earth particles.

The backlight may include at least one lamp.

The polarizing plate includes a polarizer and a protective layer laminated on top and bottom of the polarizer, respectively, to protect the polarizer, wherein the rare earth particles are added to at least one of the polarizer and the protective layer and 0.01 to about the entire composition of the polarizing plate. It is characterized in that about 0.1w%.

The rare earth particles are characterized in that about 0.01 ~ 0.1w% of the total composition of the lower substrate.

The rare earth particles are characterized in that about 0.01 ~ 0.1w% of the total composition of the light guide plate.

The rare earth particles have a diameter of about 20 to 200 nm.

Other objects and features of the present invention in addition to the above object will be apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 3 to 4.

3 is a cross-sectional view briefly showing an LCM of a conventional liquid crystal display.

The LCM shown in FIG. 3 includes a liquid crystal panel 102 having a liquid crystal cell matrix, upper and lower polarizers 142 and 140 positioned on the front and rear surfaces of the liquid crystal panel 102, and a lower liquid crystal display panel below the lower polarizer 140, respectively. The backlight unit for irradiating light is located.

The liquid crystal display panel 102 includes a lower substrate 102a having a lower array bonded therebetween with liquid crystals interposed therebetween and an upper substrate 102b having an upper array formed thereon. The lower array is composed of signal lines, thin film transistors, etc. formed on the lower substrate 102a, and the upper array is composed of color filters, black matrices, etc. formed on the upper substrate 102b. Here, the lower substrate 102a may include rare earth nanoparticles (Lanthanium Hexadoride: LaB6) 150.

The lower polarizer 140 is attached to the rear surface of the lower array substrate 102a and polarizes the light beam emitted from the backlight unit, and the upper polarizer 142 is attached to the front surface of the upper array substrate 102b so that the liquid crystal panel 102 It serves to polarize the emitted light beam. Here, the lower polarizer 140 may include rare earth nanoparticles 150.

The backlight unit includes a lamp 120 for generating light, a lamp housing 110 installed to surround the lamp 120, a light guide plate 124 for converting light incident from the lamp 120 into a planar light source; The light guide plate 124 includes a reflective plate 126 disposed on a rear surface of the light guide plate 124, and diffusion sheets 130 sequentially stacked on the light guide plate 124.

The light guide plate 124 guides the light beam generated from the light source toward the liquid crystal panel 102, and may include rare earth nanoparticles 150.

The upper and lower diffusion sheets 130 may propagate the light beam guided by the light guide plate 124 in a vertical direction to the front surface.

On the other hand, the backlight may be a direct-type backlight in which the brightness is improved by placing a plurality of fluorescent lamps in addition to the light guide plate method using the light guide plate 124 described above.

As described above, in the liquid crystal display device, rare earth nanoparticles 150 are added to at least one of the lower substrate 102a, the lower polarizer 140, and the light guide plate 124 of the liquid crystal display panel. The rare earth nanoparticles 150 serve to block infrared rays having a wavelength of about 750 to 1300 nm, which causes a temperature rise of the liquid crystal display panel without significantly affecting the transmission of visible light of the backlight. Here, the rare earth nanoparticles 150 has a diameter of about 20 to 200 nm, preferably about 60 to 100 nm.

This will be described in more detail as follows.

In general, rare earth elements (稀土 類 元素, rare earth elements) is a lanthanide-based element 14 elements below cerium is collectively referred to as lanthanides. In addition, the eleventh element in which six elements from lanthanum to samarium are combined with a cerium group element and europium to ruthetium with yttrium and scandium is called a yttrium group element. It is generally silver white or gray metal and has a chemical property such as slowly oxidizing in air, soluble in acid and hot water but insoluble in alkali, and having a predetermined size, for example, about 20 to 200 nm, preferably 60 to 100 nm. When the diameter is about, the infrared rays with relatively long wavelengths are blocked and the visible rays with shorter wavelengths are hardly blocked and transmitted.

Since the rare earth nanoparticles 150 capable of blocking the chemical properties and infrared rays as described above are included in at least one of the lower substrate 102a, the lower polarizing plate 140, and the light guide plate 124, visible light is emitted from the backlight. Is almost transmitted and blocks infrared rays which raise the temperature of the liquid crystal display panel.

Here, the rare earth nanoparticles 150 added to the lower substrate 102a may be included in an amount of about 0.01 to 0.1 w% of the total composition of the material included in the lower substrate 102a. As a result, the lower substrate 102a having the infrared ray blocking function is formed.

As a general manufacturing material of the light guide plate 124, at least one of polymethyl methacrylate (PMMA) and polycarbonate (PC) is used. The rare earth nanoparticles 150 are added in small amounts to the general material of the light guide plate 124, that is, the rare earth nanoparticles 150 having about 0.01 to 0.1 w% of the total composition of the light guide plate 124 have an infrared blocking function. The light guide plate 124 is formed.

The lower polarizer 140 has a structure in which the first and second protective layers 140a and 140c are stacked with the polarizer 140b interposed therebetween as shown in FIG. 4. Here, the polarizer 140b is formed by stretching a poly vinyl alcohol film and immersing it in an iodine and dichroic dye solution to align the iodine molecules in a stretching direction, and forming the first and second protective layers 140a, 140c) serves to prevent shrinkage of the stretched polarizer 140b and to protect the polarizer 140b using triacetate cellulose (TAC) or the like. A small amount of rare earth nanoparticles 150 is added to the polarizer 140b or the protective layers 140a and 140c of the polarizing plate 140 having the above structure, that is, at least one of the polarizer 140b and the protective layers 140a and 140c. Since the rare earth nanoparticles 150 are included in the total composition of about 0.01 to 0.1w%, a polarizing plate 140 including an infrared ray blocking function is formed.

As described above, in the liquid crystal display device according to the present invention, rare earth nanoparticles capable of blocking infrared rays are added to at least one of the lower substrate, the lower polarizer, and the light guide plate of the liquid crystal display panel. Accordingly, it is possible to prevent the deformation of the liquid crystal properties as the temperature of the conventional liquid crystal panel rises by transmitting visible light among the backlight light and blocking infrared rays. As a result, the lowering of the liquid crystal transmittance and luminance is prevented, thereby improving the image quality of the liquid crystal display panel.

As described above, in the liquid crystal display device and the manufacturing method thereof according to the embodiment of the present invention, rare earth nanoparticles capable of blocking infrared rays are added to at least one of the lower substrate, the lower polarizer, and the light guide plate of the liquid crystal display panel. As a result, the luminance of the liquid crystal display panel is improved by blocking the infrared rays of the backlight light, thereby preventing the luminance decrease and the gravity failure due to the deformation of the liquid crystal properties.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (7)

A liquid crystal panel including an upper substrate on which an upper array is formed and a lower substrate on which a lower array is formed, a polarizing plate disposed below the liquid crystal panel, and a backlight positioned under the polarizing plate to scan light to the liquid crystal display panel. In the liquid crystal display device, At least one of the lower substrate and the polarizing plate includes a rare earth particle having an infrared blocking function so that infrared light from the backlight is selectively blocked by the rare earth particles. The method of claim 1, The backlight includes a light guide plate, And the rare earth particles are included in the light guide plate. The method of claim 1, And at least one lamp is included in the backlight. The method of claim 1, The polarizing plate includes a polarizer and a protective layer laminated on top and bottom of the polarizer, respectively, to protect the polarizer. The rare earth particles are added to at least one of the polarizer and the protective layer, and the liquid crystal display device, characterized in that about 0.01 ~ 0.1w% of the total composition of the polarizing plate. The method of claim 1, The rare earth particles are liquid crystal display device, characterized in that about 0.01 ~ 0.1w% of the total composition of the lower substrate. The method of claim 2, The rare earth particles are liquid crystal display, characterized in that about 0.01 ~ 0.1w% of the total composition of the light guide plate. The method of claim 1, The diameter of the rare earth particles is a liquid crystal display device, characterized in that about 20 ~ 200nm.

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