KR20090014734A - Sheet for improving contrast, filter and display device thereof - Google Patents

Abstract

A sheet for improving contrast ratio at a bright room, a filter and a display apparatus using the same are provided to improve contrast of display image at bright room and image quality by condensing visible lights generated from a display panel toward a user side. A sheet for improving contrast ratio at bright room includes a base layer(210) and a first layer. The first layer has a plurality of lens units(220,230,240,250,260). The refractive index of the first layer is larger than that of the base layer. In the lens units, the thickness at a center portion is larger than the thickness at an outer portion.

Description

Sheet for improving contrast, filter and display device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display filter and a display device using the same, and more particularly, to a bright room contrast ratio enhancement sheet, a filter, and a display device using the same, for condensing visible light emitted from a panel to improve contrast of a display image.

In general, a plasma display panel generates a discharge by applying a predetermined voltage to electrodes provided in a discharge space, and plasma generated during gas discharge excites a phosphor, thereby displaying an image including a character or a graphic. It is advantageous in that it is easy to thin a plane, provides a wide viewing angle up and down, left and right, and realizes full color and high brightness.

The present invention has been made to solve the above-mentioned problems of the prior art, and the brightness and contrast ratio enhancement sheet that can improve the contrast contrast and image quality of the display image by converging the visible light generated from the display panel to the user side and the filter and display using the same The purpose is to provide a device.

The brightness-contrast ratio improvement sheet which concerns on this invention for solving the technical subject mentioned above is a base layer; And a first layer including a plurality of lens portions at least in contact with the base layer having a larger refractive index than the base layer and having a thickness of a central portion greater than a thickness of the outer portion.

The filter according to the present invention for solving the above technical problem, the bright room contrast ratio improving sheet; An AR sheet for preventing reflection of external light; A NIR shielding sheet for shielding near infrared rays emitted from the panel; And an EMI shielding sheet that shields electromagnetic waves.

Display device according to the present invention for solving the above technical problem, a display panel; And a bright room contrast ratio improving sheet positioned in front of the panel, wherein the bright contrast ratio enhancement sheet comprises: a base layer; And a first layer including a plurality of lens portions at least in contact with the base layer having a larger refractive index than the base layer and having a thickness of a central portion greater than a thickness of the outer portion.

According to the bright room contrast ratio improvement sheet according to the present invention configured as described above, by using a plurality of lens parts having a high refractive index to collect visible light emitted from the display panel, it is possible to improve the clear room contrast and image quality of the display image.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 10. 1 illustrates a perspective view of an embodiment of a plasma display panel.

As shown in FIG. 1, the plasma display panel includes a scan electrode 11, a sustain electrode 12, a sustain electrode pair formed on the upper substrate 10, and an address electrode 22 formed on the lower substrate 20. It includes.

The sustain electrode pairs 11 and 12 generally include transparent electrodes 11a and 12a and bus electrodes 11b and 12b formed of indium tin oxide (Indi μm-Tin-Oxide; ITO), and the bus electrodes 11b. , 12b) may be formed of a metal such as silver (Ag) or chromium (Cr) or a stack of chromium / copper / chromium (Cr / Cu / Cr) or a stack of chromium / aluminum / chromium (Cr / Al / Cr). have. The bus electrodes 11b and 12b are formed on the transparent electrodes 11a and 12a to serve to reduce voltage drop caused by the transparent electrodes 11a and 12a having high resistance.

Meanwhile, according to the exemplary embodiment of the present invention, the sustain electrode pairs 11 and 12 may not only have a structure in which the transparent electrodes 11a 12a and the bus electrodes 11b and 12b are stacked, but also the buses without the transparent electrodes 11a and 12a. Only the electrodes 11b and 12b may be configured. This structure does not use the transparent electrodes (11a, 12a), there is an advantage that can lower the cost of manufacturing the panel. The bus electrodes 11b and 12b used in this structure may be various materials such as photosensitive materials in addition to the materials listed above.

Light between the transparent electrodes 11a and 12a of the scan electrode 11 and the sustain electrode 12 and the bus electrodes 11b and 12b to absorb external light generated outside the upper substrate 10 to reduce reflection. A black matrix (BM) may be arranged that functions to block and to improve the purity and contrast of the upper substrate 10.

The black matrix according to the exemplary embodiment of the present invention is formed on the upper substrate 10, and the first black matrix 15, the transparent electrodes 11a and 12a and the bus electrode are formed at positions overlapping the partition wall 21. The second black matrices 11c and 12c formed between the 11b and 12b may be formed. Here, the first black matrix 15 and the second black matrices 11c and 12c, also referred to as black layers or black electrode layers, may be simultaneously formed and physically connected in the formation process, or may not be simultaneously formed and thus not physically connected. .

In addition, when physically connected and formed, the first black matrix 15 and the second black matrix 11c and 12c may be formed of the same material, but may be formed of different materials when they are formed separately.

Since the bus electrodes 11b and 12b or the partition wall 21 have a dark color, the light blocking function absorbs external light generated from the outside and reduces reflection, such as the black matrix, thereby improving contrast. have. Alternatively, when a particular member formed on the upper substrate 10, for example, the dielectric layer 13 and the lower member 20, for example, the partition 21 has a complementary color relationship with each other, is viewed from the front of the panel. The overlapping portions may appear to be close to black to function as the black matrix.

The upper dielectric layer 13 and the passivation layer 14 are stacked on the upper substrate 10 having the scan electrode 11 and the sustain electrode 12 side by side. Charged particles generated by the discharge are accumulated in the upper dielectric layer 13, and the protective electrode pairs 11 and 12 may be protected. The protective film 14 protects the upper dielectric layer 13 from sputtering of charged particles generated during gas discharge, and increases emission efficiency of secondary electrons.

In addition, the address electrode 22 is formed in a direction crossing the scan electrode 11 and the sustain electrode 12. In addition, a lower dielectric layer 24 and a partition wall 21 are formed on the lower substrate 20 on which the address electrode 22 is formed.

In addition, the phosphor layer 23 is formed on the surfaces of the lower dielectric layer 24 and the partition wall 21. The partition wall 21 has a vertical partition wall 21a and a horizontal partition wall 21b formed in a closed shape, and physically distinguishes the discharge cells, and prevents ultraviolet rays and visible light generated by the discharge from leaking into adjacent discharge cells. have.

Referring to FIG. 1, it is preferable that a filter 100 is formed on a front surface of the plasma display panel according to the present invention, and the filter 100 includes a bright contrast ratio improving sheet, an external light blocking sheet, and an anti-reflection (AR) filter. ), A NIR (Near Infrared) shielding sheet, an EMI (Electromagnetic Interference) shielding sheet, a diffusion sheet, an optical sheet, and the like.

In an embodiment of the present invention, not only the structure of the partition wall 21 illustrated in FIG. 1, but also the structure of the partition wall 21 having various shapes may be possible. For example, a channel in which a channel usable as an exhaust passage is formed in at least one of the differential partition structure, the vertical partition 21a, or the horizontal partition 21b having different heights of the vertical partition 21a and the horizontal partition 21b. A grooved partition structure having a groove formed in at least one of the type partition wall structure, the vertical partition wall 21a, or the horizontal partition wall 21b may be possible.

Here, in the case of the differential partition wall structure, the height of the horizontal partition wall 21b is more preferable, and in the case of the channel partition wall structure or the groove partition wall structure, it is preferable that a channel is formed or the groove is formed in the horizontal partition wall 21b. something to do.

Meanwhile, in one embodiment of the present invention, although the R, G and B discharge cells are shown and described as being arranged on the same line, it may be arranged in other shapes. For example, a Delta type arrangement in which R, G, and B discharge cells are arranged in a triangular shape may be possible. In addition, the shape of the discharge cell may be not only rectangular, but also various polygonal shapes such as a pentagon and a hexagon.

In addition, the phosphor layer 23 emits light by ultraviolet rays generated during gas discharge to generate visible light of any one of red (R), green (G), and blue (B). Here, an inert mixed gas such as He + Xe, Ne + Xe and He + Ne + Xe for discharging is injected into the discharge space provided between the upper / lower substrates 10 and 20 and the partition wall 21.

2 is a cross-sectional view illustrating a schematic structure of a brightness contrast ratio enhancement sheet according to the present invention. The brightness contrast ratio enhancement sheet according to the present invention includes a base layer 210 and a plurality of lens units 220, 230, 240, 250, 260).

The base layer 210 is preferably made of a transparent plastic material, for example, a resin-based material formed by an ultraviolet (UV) curing method so that light can be transmitted smoothly, and enhances the effect of protecting the front surface of the panel. For this purpose, a rigid glass material may be used.

Referring to FIG. 2, the refractive index of the lens units 220, 230, 240, 250, and 260, and the refractive index of at least a portion of the lens units 220, 230, 240, 250, and 260 contacting the base layer 210 may be determined by the base layer. It is preferable that it is larger than the refractive index of (210).

Visible light emitted from the panel 200 may be refracted at a portion where the lens parts 220, 230, 240, 250, and 260 and the base layer 210 contact and be focused toward the user.

Referring to FIG. 3, since the refractive index of the lens unit 270 is greater than the refractive index of the base layer 210, the light emitted from the panel 200 according to Snell's law has an angle larger than the incident angle θ1. θ2) is refracted at the portion where the lens portion 270 and the base layer 210 contact. Accordingly, as shown in FIG. 3, the light emitted from the panel 200 may be focused on the user side, which is the front of the panel, thereby improving contrast and image quality of the display image.

In order for the light emitted from the panel 200 to be refracted in the front direction of the panel at the portion where the lens unit 270 and the base layer 210 contact each other, the refractive index of the lens unit 270 is determined based on the incident angle of the panel light. It is preferable that they are 1.01 times-1.9 times the refractive index of 210).

In addition, in order to improve the light collecting efficiency of the light emitted from the panel 200 and to prevent the panel light from being reflected at the bottom of the lens unit 270 and the luminance of the display image is lowered, the refractive index of the lens unit 270 may be reduced by the base layer ( It may be 1.03 to 1.65 times the refractive index of 210).

In order to improve the clear contrast of the display image and to prevent the brightness of the image from being lowered, the visible light transmittance of the lens unit 270 is preferably 40% or more.

In one embodiment of the manufacturing method of the brightness-contrast ratio improvement sheet according to the present invention, after etching the base layer 210 made of a UV resin or the like in the shape of the lens unit 220, 230, 240, 250, 260, By filling a material having a refractive index larger than that of the base layer 210 in the etched groove, a bright room contrast ratio improving sheet may be manufactured.

4 is a cross-sectional view showing a first embodiment of the structure of the brightness contrast ratio enhancement sheet according to the present invention.

Referring to FIG. 4, when the distance c between two adjacent lens units 320 and 330 is 5 μm to 100 μm, the aperture ratio for improving the luminance of the display image is secured and the light condensing efficiency of the panel light is improved. You can.

Table 1 below shows the results of measuring the brightness and the maximum viewing angle of the display image according to the change of the angle Φ between two straight lines connecting the upper and lower ends of the lens unit 320.

In Table 1, the brightness of the display image is a value based on the brightness when the angle Φ of the lens unit is 90 degrees. Referring to Table 1, when the angle Φ of the lens unit is 90 degrees, the brightness and the maximum viewing angle of the display image have a maximum value, which decreases as the distance is far from 90 degrees.

According to the measurement result, when the brightness contrast ratio enhancement sheet according to the present invention is disposed on the front of the panel, the brightness of the display image may be improved up to about 1.25 times. Therefore, in order to condense the panel light to improve the clear contrast of the display image and not reduce the brightness of the image, the brightness of the display image is preferably in the range of 0.8 times or more of the maximum value.

Referring to FIG. 5, when the angle Φ of the lens unit is 30 to 150 degrees, the brightness of the display image is 0.8 times or more of the maximum value, thereby improving the clear contrast of the display image and not reducing the brightness of the image. Can be.

When the angle Φ of the lens portion is 30 degrees to 150 degrees, the height b of the lens portion 310 is 0.13 times to 1.87 times the lower width a. Therefore, when the height (b) of the lens unit 310 is 0.13 times to 1.87 times the lower width (a), it is possible to improve the clear room contrast without lowering the brightness of the display image.

Also, in general, when the maximum viewing angle of the display panel is 150 degrees or less, the user may feel discomfort in viewing. Referring to FIG. 6, the angle Φ of the lens unit is more preferably 60 to 120 degrees.

When the angle Φ of the lens portion is 60 degrees to 120 degrees, the height b of the lens portion 310 is 0.29 times to 0.87 times the lower width a. Therefore, when the height b of the lens unit 310 is 0.29 times to 0.87 times the lower width a, the brightness and the clear contrast of the display image may be improved while maintaining the maximum viewing angle of the panel at 150 degrees or more.

Considering the pixel size of the display panel and the angle at which the panel light is emitted, the condensing efficiency of the panel light can be improved when the bottom width a of the lens unit 310 is 40 μm to 60 μm, thereby improving the display image. In order not to lower the brightness, the height b of the lens unit 310 is preferably 16 μm to 36 μm.

7 to 9 are sectional views showing embodiments of a schematic configuration of a display device having a light contrast ratio enhancing sheet according to the present invention.

Referring to FIG. 7, in order for the light emitted from the panel 360 to be focused in the front direction of the panel, the focal point of the lens unit 350 and the panel 360 are considered in consideration of the size of the lens unit 350 as described above. It is preferable that the space | interval d1 between them is 3 mm or less. In addition, considering the relationship between the height of the lens unit 350 and the bottom width as described above, when the distance d2 between the lens unit 350 and the panel 360 is less than 4mm is emitted from the panel 360 Light may be collected in the front direction of the panel.

Referring to FIG. 8, in the contrast contrast enhancing sheet according to the present invention, an antireflection layer 430 formed of a material having a refractive index smaller than that of the lens unit 420 may be formed between the lens unit 420 and the panel 400.

By arranging the antireflection layer 430 having a refractive index smaller than that of the lens unit 420 under the lens unit 420, it is possible to prevent the light emitted from the panel 400 from being reflected at the lower end of the lens unit 420. . Therefore, the brightness of the display image can be improved.

Although not shown in FIG. 8, an adhesive layer for fixing the two layers may be formed between the lens unit 420 and the anti-reflection layer 430.

2 to 8, the light and dark contrast ratio improvement sheet according to the present invention has been described with reference to the example in which the lens unit has a convex shape in the opposite direction of the panel. However, as shown in FIG. The lens units 520, 530, 540, 550, and 560 may have a convex shape in the panel direction.

10 to 14 show in cross-sectional views a second to sixth embodiments of the structure of the bright contrast ratio enhancing sheet according to the present invention.

Referring to FIG. 10, the cross-sectional shape of the lens unit 610 formed in contact with the base layer 600 may be a triangle, and preferably an isosceles triangle.

Referring to FIG. 12, the cross-sectional shape of the lens unit 650 may be trapezoidal. In addition, as shown in FIG. 11, the inclined surface of the lens unit 630 may have a convex shape.

In addition, as shown in FIGS. 11 and 13, the inclined surface of the lens unit 630 may have a convex shape, and in this case, the light condensing efficiency of the panel light may be improved.

Referring to FIG. 14, the lower end of the lens unit 710 may have a concave shape. By forming a concave groove at the bottom of the lens portion 710 as shown in Figure 14, it is possible to increase the contact surface with the other functional layer or sheet bonded to the bottom of the brightness contrast ratio enhancement sheet, thereby improving the contrast contrast ratio The mechanical strength of the filter comprising the sheet can be improved. In addition, by reducing the angle of the panel light incident on the lower end of the lens unit 710, it is possible to prevent the panel light is reflected from the lower end of the lens unit 710, thereby improving the brightness of the display image.

15 is a cross-sectional view of an embodiment of a schematic structure of a filter according to the present invention. The filter 800 according to the present invention may include an AR / NIR sheet 800, an EMI shield sheet 820, and a clear contrast ratio. It may include a sheet 830.

Referring to FIG. 15, the AR / NIR sheet 810 has a function of reducing glare by preventing reflection of light incident from the outside on the front surface of the base sheet 813 made of a transparent plastic material. A reflection layer 811 is attached, and a rear infrared shielding sheet 812 for shielding near infrared rays emitted from the panel so that signals transmitted using infrared rays such as a remote controller can be normally transmitted can be attached. Can be.

The EMI shield sheet 820 shields the electromagnetic interference (EMI) to prevent the EMI emitted from the panel from being emitted to the outside, and the plurality of conductive layers, for example, the plurality of metal layers and the transparent transparent layers alternately. It may have a stacked structure.

An adhesive layer 840 may be formed between the AR / NIR sheet 810, the EMI shielding sheet 820, and the bright contrast ratio improving sheet 830, and the sheets 810, 820, 830, and the filter 800 may be formed. ) To be firmly attached to the front of the panel. In addition, the material of the base sheet included between each of the sheets 810, 820, and 830 may preferably use substantially the same material in consideration of the ease of fabrication of the filter.

Meanwhile, in FIG. 15, the AR / NIR sheet 810, the EMI shielding sheet 820, and the bright contrast ratio enhancement sheet 830 are stacked in this order, but the stacking order of each sheet may be differently stacked by those skilled in the art. In addition, at least one of the illustrated sheets 810, 820, and 830 may be omitted, or another functional layer may be added.

At least one of the basesheets shown in FIG. 15 may be omitted, and any one of the basesheets may be made of hard glass, which is not made of plastic, to improve a function of protecting the panel. . The glass is preferably formed spaced apart from the panel at a predetermined interval.

In the filter according to the present invention, an optical sheet (not shown) may improve color temperature, color purity, or luminance characteristics of light incident from a panel, and may include a dye that absorbs light of a specific wavelength band on the front or rear surface of a base sheet made of a transparent plastic material. An optical layer composed of a pigment and an adhesive may be laminated.

Typically, the external light source is most often present at the top of the observer's head, indoors or outdoors. Therefore, the filter according to the present invention may further include an external light shielding sheet (not shown) in order to effectively block external light so that the black image of the plasma display panel can be darker.

In addition, the filter according to the present invention may further include a diffusion sheet (not shown). The diffusion sheet (not shown) serves to diffuse the incident light so that the light maintains uniform brightness. Accordingly, the diffusion sheet (not shown) can spread the light emitted from the panel uniformly to widen the vertical viewing angle of the display screen, and conceal the pattern formed in the external light blocking sheet or the like. In addition, the diffusion sheet (not shown) can collect light in a direction corresponding to the vertical viewing angle, make the front luminance uniform, and improve the antistatic property.

As the diffusion sheet (not shown), a transmissive or reflective diffusion film or the like may be used. In general, the diffusion sheet may have a form in which small glass beads are mixed in a base sheet of a polymer material. In addition, high purity acrylic resin (PMMA) may be used as a base sheet of the diffusion sheet (not shown), and when the high purity acrylic resin (PMMA) is used, the sheet is thick but has good heat resistance and is used for a large display device having high heat generation. Can be.

The filter including the bright contrast ratio improvement sheet according to the present invention as described above may be formed as a film filter type to be attached to the panel using adhesion, otherwise the glass filter type including a glass spaced apart from the panel It may also be formed as.

In the above, the filter according to the present invention has been described as an embodiment, which is disposed on the front surface of the plasma display panel. It can be used for various display devices.

Although a preferred embodiment of the present invention has been described in detail above, those skilled in the art to which the present invention pertains can make various changes without departing from the spirit and scope of the invention as defined in the appended claims. It will be appreciated that modifications or variations may be made to the branches. Accordingly, modifications to future embodiments of the present invention will not depart from the technology of the present invention.

1 is a perspective view illustrating an embodiment of a structure of a plasma display panel.

2 is a cross-sectional view showing a schematic structure of a bright room contrast ratio improving sheet according to the present invention.

3 is a cross-sectional view for illustrating a light condensing function of a bright room contrast ratio improving sheet according to the present invention.

4 is a cross-sectional view showing a first embodiment of the structure of the bright room contrast ratio improving sheet according to the present invention.

5 and 6 are graphs illustrating measurement results of brightness and maximum viewing angle of a display image according to the shape of a lens unit of a bright room contrast ratio improving sheet.

7 to 9 are cross-sectional views illustrating embodiments of a schematic configuration of a display device having a light contrast ratio enhancing sheet according to the present invention.

10 to 14 are cross-sectional views showing the second to sixth embodiments of the structure of the bright contrast ratio enhancement sheet according to the present invention.

15 is a cross-sectional view showing an embodiment of a schematic structure of a filter including a light contrast ratio enhancing sheet according to the present invention.

Claims (20)

Base layer; And And at least a portion in contact with the base layer having a refractive index greater than that of the base layer, the first layer including a plurality of lens portions having a thickness of a central portion greater than a thickness of an outer portion. The method of claim 1, The refractive index of the lens unit is 1.01 times to 1.9 times the refractive index of the base layer, the contrast ratio enhancement sheet. The method of claim 1, The refractive index of the lens unit is 1.03 times to 1.65 times the refractive index of the base layer, the contrast ratio enhancement sheet. The method of claim 1, The visible light transmittance of the lens unit is a bright room contrast ratio improvement sheet, characterized in that 40% or more. The method of claim 1, The height of the lens unit is 0.13 times to 1.87 times the width of the lower end of the lens unit, the contrast ratio enhancement sheet. The method of claim 1, The height of the lens unit is 0.29 times to 0.87 times the width of the lower end of the lens unit, the contrast ratio enhancement sheet. The method of claim 1, The clear contrast ratio improvement sheet, characterized in that the interval between the two adjacent lens portion of the plurality of lens portion is 5㎛ to 100㎛. The method of claim 1, Further comprising a second layer having a smaller refractive index than the lens unit, And the lens unit is positioned between the base layer and the second layer. The method of claim 8, The adhesion layer is formed between the said 1st, 2nd layer, The clear-room contrast ratio improvement sheet characterized by the above-mentioned. The method of claim 1, The lower portion of the lens unit has a concave shape, characterized in that the contrast ratio enhancement sheet. The clear room contrast ratio improvement sheet in any one of Claims 1-10; And An AR sheet for preventing reflection of external light; A NIR shielding sheet for shielding near infrared rays; And an EMI shielding sheet for shielding electromagnetic waves. Display panel; And a bright room contrast ratio enhancement sheet located at the front of the panel. The brightness contrast ratio improvement sheet Base layer; And And a first layer including a plurality of lens portions at least in contact with the base layer having a larger refractive index than the base layer and having a thickness of a central portion greater than a thickness of an outer portion. The method of claim 12, The refractive index of the lens unit is a display device, characterized in that 1.01 to 1.9 times the refractive index of the base layer. The method of claim 12, And a visible light transmittance of the lens unit is 40% or more. The method of claim 12, The height of the lens unit is a display device, characterized in that 0.13 times to 1.87 times the bottom width of the lens portion. The method of claim 12, And a distance between two adjacent lens parts of the plurality of lens parts is 5 μm to 100 μm. The method of claim 12, And a distance between the focus of the lens unit and the panel is 3 mm or less. The method of claim 12, And a gap between the lens unit and the panel is 4 mm or less. The method of claim 12, The lens unit has a convex shape in the opposite direction of the panel. The method of claim 12, wherein the contrast contrast enhancement sheet And a second layer having a lower refractive index than the lens unit between the first layer and the panel.

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