KR100838599B1 - Plasma display device - Google Patents

Abstract

A plasma display apparatus is provided to effectively implement a black image by positioning an external light shielding sheet absorbing and shielding external light on a front surface of a display panel. A plasma display panel has an upper substrate, a dielectric layer formed on the upper substrate, a lower substrate, and barrier ribs formed on the lower substrate for defining discharge cells. A filter is provided on the upper substrate of the panel. The filter has an external light shielding sheet consisting of base portions and plural pattern portions(720) formed on the base portions. The barrier rib has a horizontal barrier rib formed in a direction crossing an electrode formed on the lower substrate. A mutual angle between an overlapped portion(700) of the upper end of the horizontal barrier rib and the dielectric layer and the pattern portion is 0.5 to 20 degrees.

Description

Plasma display device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display device. In particular, in order to block external light incident from the outside of a panel, an external light shielding sheet is manufactured and attached to the front surface of the panel, thereby improving contrast and maintaining brightness of the panel. The present invention relates to a plasma display device.

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.

In the panel as described above, when the black image is implemented, external light is reflected from the front of the panel due to the white phosphor exposed on the lower panel of the panel, so that the black image is perceived as a dark color of a bright series and the contrast is reduced. There is a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and effectively blocks external light incident on the display panel, thereby improving contrast and improving brightness of the panel, and reducing moire. It is an object of the present invention to provide a filter and a plasma display device using the same.

According to an aspect of the present invention, there is provided a plasma display apparatus comprising: a plasma display panel formed by combining an upper substrate and a lower substrate; And a filter formed on the front surface of the panel, wherein the filter comprises: a base part; And an external light shielding sheet including a plurality of pattern portions formed on the base portion, wherein the partition wall includes a horizontal partition wall formed in a direction crossing the electrode formed on the lower substrate, and an upper end of the horizontal partition wall and the An angle between an overlapping portion of the dielectric layer and the pattern portion is 0.5 to 20 degrees.

Another plasma display device according to the present invention for solving the above technical problem is characterized in that the width of the portion where the upper end of the horizontal partition wall and the dielectric layer overlap is 1.3 to 5 times the width of the bottom of the pattern portion.

In another plasma display device according to the present invention for solving the above technical problem, a distance between an upper portion of the horizontal partition wall and two overlapping portions adjacent to each other among overlapping portions of the dielectric layer is equal to 6 of a gap between the lower ends of the pattern portions adjacent to each other. It is characterized in that the pear to 20 times.

According to the filter and the plasma display device using the same according to the present invention configured as described above, it is possible to effectively implement a black image by placing an external light shielding sheet that absorbs and blocks the light incident from the outside to the front of the display panel. And can improve the contrast. In addition, by forming a ratio or an angle between the pattern portion of the external light blocking sheet, the partition and the overlapping portion of the dielectric layer within a predetermined range, it is possible to improve the brightness of the display image and reduce the moiré phenomenon.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 1 to 30. 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 reduce the 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 physically separated.

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, a specific member formed on the upper substrate 10, for example, the dielectric layer 13 and the specific member formed on the lower substrate 20, for example, the partition wall 21, have a complementary color relationship with each other, so that they overlap when viewed from the front of the panel. It can also function as the black matrix by making the portion appear closer to black.

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 the front surface of the plasma display panel according to the present invention, and the filter 100 has an external light blocking sheet, an anti-reflection (AR) sheet, and a near infrared shield (NIR). Sheets, EMI (Electromagnetic Interference) shielding sheet, diffusion sheet, optical properties sheet and the like can be included.

When the distance between the filter 100 and the panel is 10 μm to 30 μm, light incident from the outside may be effectively blocked, and light emitted from the panel may be effectively emitted to the outside. In addition, in order to protect the panel from the pressure from the outside, the distance between the filter 100 and the panel can be 30㎛ to 120㎛, and between the filter 100 and the panel to prevent impact An adhesive layer having a function of shock absorption may be formed.

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 each of 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 showing an embodiment of the external light blocking sheet structure provided in the filter according to the present invention, the external light blocking sheet comprises a base portion 200 and the pattern portion 210.

Base portion 200 is preferably made of a transparent plastic material, for example, a resin-based material formed by UV (UV) curing, so as to transmit light smoothly, and enhances the effect of protecting the front of the panel For this purpose, a rigid glass material may be used.

Referring to FIG. 2, the pattern portion 210 may have a triangular shape, or may have various shapes. The pattern part 210 is formed of a material of darker color than the base part 200, and preferably, a material of black color. For example, the pattern unit 210 may be formed of a carbon-based material or may apply a black dye to maximize the effect of absorbing external light. Hereinafter, the wider of the upper and lower ends of the pattern unit 210 is referred to as the lower end of the pattern unit 210.

In FIG. 2, the lower end of the pattern part 210 may be disposed on the panel side, and the upper end of the pattern part 210 may be disposed on the observer side where external light is incident. In addition, in contrast to the arrangement, the lower end of the pattern portion 210 may be disposed toward the observer side, and the upper end of the pattern portion 210 may be disposed on the panel side.

Since the external light source is generally located above the panel, the external light is incident on the panel at an angle from the upper side and absorbed by the pattern portion 210.

The pattern unit 210 may include light absorbing particles, and the light absorbing particles may be resin particles colored in a specific color. In order to maximize the light absorption effect, the light absorbing particles are preferably colored black.

In order to facilitate the manufacture of the light absorbing particles and the addition into the pattern portion 210 and to maximize the effect of absorbing external light, the size of the light absorbing particles may be 1 μm or more. In addition, when the size of the light absorbing particles is 1 μm or more, the pattern unit 210 may include 10 wt% or more of the light absorbing particles in order to effectively absorb external light refracted by the pattern unit 210. That is, light absorbing particles having a weight of 10% or more of the total weight of the pattern portion 210 may be included in the pattern portion 210.

3 to 6 are sectional views showing embodiments of the structure of the external light blocking sheet to explain the optical characteristics according to the structure of the external light blocking sheet.

In FIG. 3, in order to absorb and block external light and totally reflect visible light emitted from the panel to increase the reflectance of the panel light, the refractive index of the pattern portion 305 and the refractive index of the inclined surface that is at least a part of the pattern portion 305 are based on. This is the case where the refractive index of the portion 300 is smaller than that.

As described above, the external light that lowers the clear room contrast of the plasma display panel is often located above the panel. Referring to FIG. 3, according to Snell's law, external light (indicated by dashed lines) obliquely incident on the external light blocking sheet is refracted and absorbed into the pattern part 310 having a refractive index smaller than that of the base part 300. . External light refracted into the pattern portion 305 may be absorbed by the light absorbing particles.

 In addition, light (shown in solid line) emitted from the panel 310 to the outside for display is totally reflected on the inclined surface of the pattern portion 305 to be reflected to the outside, which is the observer's side.

As described above, the external light (indicated by the dotted line) is refracted and absorbed by the pattern portion 305 and the light emitted by the panel 310 (indicated by the solid line) is totally reflected by the pattern portion 305. As shown, the angle between the light of the panel 310 and the inclined surface of the pattern portion 305 is greater than that of the inclined surface of the pattern portion 305.

Therefore, the external light blocking sheet according to the present invention absorbs external light so that the external light is not reflected to the observer side, and improves the clear contrast of the display image by increasing the amount of reflection of the light emitted from the panel 310.

In order to maximize absorption of external light and total reflection of light of the panel 310 in consideration of the angle of external light incident on the panel 310, the refractive index of the pattern part 305 is 0.3 times or more and less than 1 times the refractive index of the base part 300. It is preferable. In order to maximize the total reflection of the light emitted from the panel 310 on the inclined surface of the pattern portion 305, considering the vertical viewing angle of the plasma display panel, the refractive index of the pattern portion 305 is 0.3 times the refractive index of the base portion 300. It is preferable that it is times-0.8 times.

As shown in FIG. 3, when the upper end of the pattern portion 305 is disposed on the observer side and the refractive index of the pattern portion 305 is smaller than the refractive index of the base portion 300, the light emitted from the panel is pattern portion 305. Because it is reflected from the inclined surface of the and spreads to the observer's side, a ghost phenomenon may occur when the image is not clear and distorted when viewed from the observer's side.

4 illustrates a case where the upper end of the pattern part 325 is disposed on the observer side and the refractive index of the pattern part 325 is larger than the refractive index of the base part 320. Referring to FIG. 4, since the refractive index of the pattern portion 325 is greater than the refractive index of the base portion 320, both external light and panel light incident on the pattern portion 325 according to Snell's law are absorbed by the pattern portion 325. do.

Therefore, when the upper end of the pattern portion 325 is disposed on the observer side and the refractive index of the pattern portion 325 is larger than the refractive index of the base portion 320, the ghost phenomenon may be reduced. In order to sufficiently absorb the panel light incident at an angle to the pattern portion 325 to prevent ghosting, the difference between the refractive index of the pattern portion 325 and the refractive index of the base portion 320 is preferably 0.05 or more.

When the refractive index of the pattern portion 325 is larger than the refractive index of the base portion 320, the transmittance and clear room contrast of the external light shielding sheet may be reduced, thereby preventing ghosting and greatly reducing the transmittance of the external light shielding sheet. In order not to, the difference between the refractive index of the pattern portion 325 and the refractive index of the base portion 320 is preferably 0.05 to 0.3. In addition, in order to prevent the ghost phenomenon and maintain the clear yarn coat of the panel at an appropriate level, the refractive index of the pattern portion 325 is preferably 1.0 times to 1.3 times the refractive index of the base portion 320.

5 illustrates a case where the lower end of the pattern part 345 is disposed on the observer side and the refractive index of the pattern part 345 is smaller than the refractive index of the base part 340. As illustrated in FIG. 5, the lower end of the pattern part 345 is disposed on the side of the observer to which external light is incident, so that the external light is absorbed by the lower end of the pattern part 345, thereby improving external light blocking effect. In addition, since the interval between the lower ends of the pattern portion 345 can be made larger than that shown in FIG. 4, the aperture ratio of the external light blocking sheet can be improved.

As shown in FIG. 5, the panel light emitted from the panel 350 may be reflected at the inclined surface of the pattern part 345, and may be gathered around the panel light passing through the base part 340. Therefore, the ghost phenomenon can be reduced without significantly reducing the transmittance of the external light shielding sheet.

In order to prevent the ghost phenomenon as the panel light is reflected from the inclined surface of the pattern portion 345 and passes through the base portion 340 as the center, the distance d between the panel 350 and the external light blocking sheet It is preferable that it is 1.5-3.5 mm.

6 illustrates a case where the lower end of the pattern part 365 is disposed at the observer's side and the refractive index of the pattern part 365 is greater than the refractive index of the base part 360. As shown in FIG. 6, since the refractive index of the pattern portion 365 is greater than the refractive index of the base portion 360, the panel light incident on the inclined surface of the pattern portion 365 may be absorbed by the pattern portion 365. Accordingly, since the image is displayed by the panel light passing through the base 360, the ghost phenomenon can be reduced.

In addition, since the refractive index of the pattern portion 365 is greater than the refractive index of the base portion 360, the external light absorption effect may be improved.

7 is a sectional view showing a first embodiment of the structure of the external light blocking sheet provided in the filter according to the present invention. When the thickness T of the external light shielding sheet is 20 μm to 250 μm, the manufacturing process may be easy and may have an appropriate light transmittance. In order to smoothly transmit the light emitted from the panel, the light incident from the outside is refracted to be effectively absorbed and blocked by the pattern portion 410, and to secure the sheet, the thickness T of the external light blocking sheet is 100 μm to 180 μm.

Referring to FIG. 7, the pattern part 410 formed on the base part 400 may have a triangular shape, and more preferably, may have an isosceles triangular shape. In addition, the bottom width P1 of the pattern portion 410 may be formed to 18㎛ to 36㎛, in such a case to secure the aperture ratio for the light emitted from the panel can be smoothly emitted to the user side, the external light blocking efficiency Can be maximized.

The height h of the pattern portion 410 is formed to be 80 μm to 170 μm, thereby forming an inclined surface slope capable of effectively absorbing external light and reflecting panel light in relation to the bottom width P1. Short circuit of the part 410 can be prevented.

The panel light is emitted to the user side to secure an aperture ratio for displaying a display image having an appropriate brightness, and to secure an optimal pattern part 410 inclination slope for increasing the external light blocking effect and panel light reflection efficiency, The spacing D1 between the pattern parts may be 40 μm to 90 μm, and the spacing D2 between the upper ends of the pattern parts may be 90 μm to 130 μm.

For the above reason, when the distance D1 between two adjacent pattern parts is 1.1 to 5 times the width of the lower end of the pattern part 410, an opening ratio for the display can be secured. In addition, in order to secure the aperture ratio and optimize the external light blocking effect and the panel light reflection efficiency, the distance D1 between two adjacent pattern parts may be 1.5 to 3.5 times the width of the bottom of the pattern part 410.

When the height h of the pattern portion 410 has a range of 0.89 times to 4.25 times the interval D1 between two adjacent pattern portions, external light incident at an angle from the upper side may not be incident to the panel. In addition, in order to prevent short circuit of the pattern portion 410 and to optimize reflection efficiency of the panel light, the height h of the pattern portion 410 may be 1.5 to 3 times the distance D1 between two adjacent pattern portions. .

In addition, when the distance D2 between the upper ends of the two pattern parts adjacent to each other is 1 to 3.25 times the distance D1 between the lower ends of the two pattern parts adjacent to each other, an aperture ratio for displaying an image having an appropriate luminance may be secured. . In addition, in order to optimize the reflection efficiency in which the panel light is totally reflected on the inclined surface of the pattern portion 410, the distance D2 between two adjacent upper ends of the pattern parts is 1.2 times the distance D1 between the lower ends of the two pattern parts adjacent to each other. To 2.5 times.

In the above, the structure of the exterior light shielding sheet according to the present invention has been described with an example in which the upper end of the pattern part 410 is disposed toward the observer side, but the contents described above with reference to FIG. It is also applicable when the lower end is disposed to the observer side.

8 and 9 illustrate an embodiment of the front shape of the pattern portions formed in a row on the external light blocking sheet, and as shown, the pattern portions are preferably formed in a row at predetermined intervals on the base portion.

The moiré phenomenon may occur by overlapping a plurality of pattern portions formed in the external light blocking sheet at predetermined intervals and portions formed with the predetermined pattern on the panel such as a black matrix, a black layer, a bus electrode, a partition wall, and the like. The moiré phenomenon is a low frequency pattern generated by overlapping similar lattice patterns. For example, the moiré pattern shows a wave pattern when the mosquito nets are stacked.

As shown in FIG. 8 and FIG. 9, by forming the plurality of pattern portions at an angle, moiré phenomena generated by overlapping with a black matrix, a black layer, a bus electrode, and a partition wall formed in the panel can be reduced.

As shown in FIG. 10, since the black matrix 610 is formed on the upper substrate of the panel in a direction parallel to the horizontal partition wall formed on the lower substrate of the panel, the black matrix is formed on the top of the external light blocking sheet of FIGS. 8 and 9. Or parallel to the bottom. Therefore, in FIG. 9, angles Θ ₁ , Θ ₂ , and Θ _{3 that} the pattern portion forms with the upper end of the external light blocking sheet represent angles that the pattern portion of the external light blocking sheet forms with the black matrix formed on the panel.

When the pattern portion of the external light blocking sheet is formed at an angle with an angle between 0.5 degrees and 20 degrees with the black matrix formed on the panel, the moiré phenomenon can be reduced. In addition, considering that the external light incident on the panel is often present at the top of the user's head, when the angle between the pattern portion and the black matrix is 0.5 degrees to 5 degrees, the moir phenomenon is prevented and an appropriate aperture ratio is secured. It is possible to increase the reflection efficiency of the panel light and to block the external light most effectively.

FIG. 9 is an enlarged view of a portion 500 of the external light blocking sheet illustrated in FIG. 8, and the pattern portions 510, 520, 530, 540, 550, and 560 formed in a line are preferably parallel to each other, and are parallel to each other. Even if not, it is preferable that the angles between the pattern portions 510, 520, 530, 540, 550, and 560 and the black matrix have the ranges described above, respectively.

In addition, when the angle (Θ ₁ , Θ ₂ , Θ ₃ ) between the pattern portion of the external light blocking sheet and the transverse partition formed on the lower substrate or the bus electrode formed on the upper substrate of the panel is 0.5 to 20 degrees, Moiré phenomenon can be reduced. In addition, considering that the external light incident on the panel is often present at the top of the user's head, the angle Θ ₁ , Θ ₂ , Θ ₃ between the pattern portion and the bus electrode or the horizontal partition wall is 0.5 degrees to At 5 degrees, it is possible to prevent moiré phenomena and at the same time to secure an appropriate aperture ratio to increase the reflection efficiency of the panel light, and to block external light most effectively.

8 and 9, the pattern portion is formed obliquely in the upper left direction from the lower right side of the external light blocking sheet, but in another embodiment, the pattern portion has the angle as described above in the upper left direction from the upper left of the external light blocking sheet. It may be formed at an angle.

Figure 10 briefly illustrates one embodiment of the structure of the black matrix formed on the panel.

Referring to FIG. 10, the black matrix 610 may be formed to overlap a horizontal partition wall formed on the lower substrate 600. In addition, as illustrated in FIG. 10, the black matrix 610 may be formed to overlap the scan electrode and the sustain electrode formed on the upper substrate so that the scan electrode and the sustain electrode may be covered by the black matrix 610.

In this case, when the width b of the black matrix 610 is 200 μm to 400 μm and the spacing a between the adjacent black matrices is 300 μm to 600 μm, the display image has an appropriate brightness. In addition to ensuring the aperture ratio of the panel, it is possible to maximize the light blocking efficiency of absorbing external light generated from the outside to reduce reflection and improving the purity and contrast of the upper substrate.

When the black matrix 610 is formed to overlap the scan electrode and the sustain electrode as shown in FIG. 10, the width b of the black matrix 610 is 10 times to the width P1 of the pattern portion of the external light blocking sheet. At 15 times, it prevents moiré and at the same time secures the proper opening ratio of the panel and maximizes the external light blocking efficiency, and the distance (a) between the adjacent black matrices is 4 to 9 times the distance between the adjacent pattern parts. When the panel light reflection efficiency can be optimized, the moiré phenomenon can be reduced.

11 to 14 illustrate cross-sectional embodiments of a structure in which an upper portion of a partition wall and a dielectric layer overlap, according to an embodiment of the present invention. The first overlapping portion 700 and the upper portion of the vertical partition wall and the second overlapping portion 710 in the vertical direction in which the dielectric layer overlaps are briefly illustrated.

The color of the barrier rib and the color of the dielectric layer formed on the upper substrate of the panel may be complementary to each other. In such a case, the color of the portions 700 and 710 overlapping the barrier rib and the dielectric layer may be black or a dark gray color close thereto. Can have

For example, the barrier ribs and the dielectric layers may have blue and yellow colors, or may have complementary colors such as red and green colors.

As shown in FIG. 11, the portions 700 and 710 where the upper end of the partition wall and the dielectric layer overlap each other form a predetermined pattern on the panel, and thus, as described above with the external light blocking sheet formed on the front surface of the panel. Moiré may occur.

As shown in FIG. 12, it is possible to prevent the moiré phenomenon occurring between the pattern portion 720 and the pattern formed by the overlapping portions 700 and 710 of the partition wall by forming the pattern portion 720 of the external light blocking sheet at an angle. desirable.

When the angle θ ₄ formed between the upper part of the horizontal partition wall formed on the panel and the first overlapping part 700 where the dielectric layer overlaps with each other is 0.5 to 20 degrees, the moiré phenomenon may be effectively reduced. In addition, considering that the external light incident on the panel is often present at the top of the user's head, the angle θ ₄ between the pattern portion and the first overlapping portion 700 in the horizontal direction is 0.5 degrees to 5 degrees. At the same time to prevent the moiré phenomenon at the same time to secure the appropriate aperture ratio can increase the reflection efficiency of the panel light, it is possible to block the external light most effectively.

Referring to FIG. 13, the distance c between two overlapping portions 700 and 710 in the horizontal direction adjacent to each other in order to secure proper brightness and resolution of the display image is preferably 540 μm to 800 μm. Accordingly, considering that the distance between two adjacent pattern parts 40 to 90 μm for securing the appropriate aperture ratio of the panel and increasing the external light blocking effect and the panel light reflection efficiency, the two overlapping portions in the horizontal direction adjacent to each other ( The spacing c between 700 and 710 is preferably 6 to 20 times the spacing between two adjacent pattern parts.

In addition, when the distance between the pattern portions adjacent to each other is 40 μm to 60 μm and the distance c between the two overlapping portions 700 and 710 in the horizontal direction adjacent to each other is 600 μm to 700 μm, the pattern portion of the external light blocking sheet The moiré phenomenon caused by the overlap of the horizontal partition walls of the panel can be reduced. Therefore, when the distance (c) between the two overlapping portions 700 and 710 in the horizontal direction adjacent to each other is 10 to 17.5 times the distance between the two pattern portions adjacent to each other, the external light absorbed from the outside reduces reflection. Moiré phenomena can be reduced while maximizing light blocking efficiency and efficiency to improve the purity and contrast of the upper substrate.

 As described with reference to FIG. 7, the width of the lower end of the pattern portion of the external light blocking sheet is preferably 18 μm to 35 μm, and the width d of the horizontal overlapping portion 700 in which the upper end of the horizontal partition wall and the dielectric layer overlap each other. When the range of 45 μm to 90 μm, the aperture ratio of the panel for ensuring that the display image has an appropriate brightness can be ensured. Therefore, in order to secure the aperture ratio of the panel so that the display image has an appropriate brightness, and to reduce the moiré phenomenon caused by the overlap between the pattern portion of the external light blocking sheet and the horizontal partition wall of the panel, the overlapping portion 700 in the horizontal direction The width d of 710 is preferably 1.3 to 5 times the width of the bottom of the pattern portion.

In addition, when the width d of the overlapped portions 700 and 710 in the horizontal direction is 2.5 to 3.5 times the width of the lower end of the pattern portion, the transmittance of visible light emitted from the discharge space and the reflectance in the external light blocking sheet may be optimized.

As shown in FIG. 14, a width of a portion of the portions 800 and 810 where the partition wall and the dielectric layer overlap may be different from other portions. When the overlapping portions 800 and 810 of the partition wall and the dielectric layer have a structure as shown in FIG. 14, the gap c between two adjacent overlapping portions 800 and 810 adjacent to each other and the first overlapping portion 800 in the horizontal direction are provided. Width d) may be defined based on a straight portion.

15 to 19 illustrate cross-sectional views of embodiments of a pattern portion of an exterior light blocking sheet.

Referring to FIG. 15, the pattern portion 900 may be formed in left and right asymmetric shapes. That is, the area of the left and right inclined surfaces of the pattern portion 900 may be different, or the angles of the lower and left sides of the left and right inclined surfaces may be different from each other. In general, since objects generating external light are located above the panel, external light is incident from the top of the panel to the panel within a predetermined angle range. Therefore, in order to increase the external light absorbing effect and increase the reflectance of the light emitted from the panel, the inclination of the upper inclined surface to which the external light is incident can be gentler than the inclination of the lower inclined surface of the two inclined surfaces of the pattern portion 900. That is, the inclination of the upper inclined surface of the two inclined surfaces of the pattern portion 900 may be smaller than the inclination of the lower inclined surface.

Referring to FIG. 16, the pattern portion 910 may have a trapezoidal shape, in which case, the upper width P2 is smaller than the lower width P1. In addition, the width P2 of the upper end of the pattern portion 910 may be 10 μm or less, thereby forming an inclined surface slope capable of effectively absorbing external light and reflecting panel light in a relationship with the lower width P1. .

17 to 19, the pattern portions 920, 930, and 940 of the external light blocking sheet may have a curved shape in which left and right inclined surfaces have a predetermined curvature. In this case, in order to improve the blocking effect of the external light incident at an angle, it is preferable that the amount of change of the inclination of the inclined surfaces of the pattern parts 920, 930, and 940 decreases from the lower end to the upper end.

In addition, in embodiments of the shape of the pattern portion illustrated in FIGS. 17 to 19, the corner portion of the pattern portion may have a curved shape having a predetermined curvature.

20 is a sectional view showing an embodiment of the shape of the pattern portion having a concave shape at the bottom.

As shown in FIG. 20, the lower end 1015 of the pattern part has a concave shape in which the center is rounded or recessed in the middle, so that the image generated as the light emitted from the panel is reflected from the lower end 1015 of the pattern part. It is possible to reduce the bleeding phenomenon of, and when the external light blocking sheet is attached to another functional sheet or panel, it is possible to improve the adhesive force by increasing the area of the bonding site.

That is, by forming the pattern portion 1010 so that the height at the center portion is smaller than the height at the outermost portion, the pattern portion 1010 including the concave lower end 1015 can be formed.

The pattern portion 1010 may be formed by filling a light absorbing material or the like in a groove formed in the base portion 1000, wherein a portion of the groove formed in the base portion 1000 forms the pattern portion 1010. Can be filled in, and the rest can be left blank. Accordingly, the lower end 1015 of the pattern portion may have a concave shape in which a center portion thereof is drawn in.

As shown in FIG. 21, when the bottom of the pattern portion 1030 is flat, light emitted from the panel and obliquely incident to the bottom of the pattern portion 1030 may be reflected in the panel direction. As described above, an image to be displayed at a specific position is displayed around the specific position by the panel light reflected in the panel direction, so that an image blur phenomenon may occur to reduce the sharpness of the display image.

Referring to FIG. 22, the incident angle θ2 of light incident obliquely to the lower end of the concave pattern portion 1010 is smaller than the incident angle θ1 incident on the lower end of the flat pattern portion 1030 shown in FIG. 21. do. Accordingly, the panel light reflected from the bottom of the flat pattern portion 1030 illustrated in FIG. 21 may be absorbed into the pattern portion 1010 at the bottom of the pattern portion 1010 having the concave shape illustrated in FIG. 22. As a result, blurring of the display image may be reduced to improve sharpness of the image.

FIG. 23 is a cross-sectional view showing an embodiment of the structure of an external light shielding sheet including a pattern portion having a concave lower end, and the lower end of the pattern portion 1110 is arranged in an observer side.

Referring to FIG. 23, the incidence angle range of external light absorbed by the lower end of the pattern part 1110 may be enlarged by concave the lower end of the pattern part 1110 disposed on the observer side. That is, when the lower end of the pattern portion 1110 is concave, the incident angle of the external light to the lower end of the pattern portion 1110 can be increased, thereby improving the external light absorption effect.

24 is a sectional view showing an embodiment of the shape of the pattern portion having a concave shape at the bottom. Table 1 below shows the results of experiments on whether or not the blurring phenomenon of the display image is reduced according to the depth (a) of the groove formed by forming the lower end of the pattern part 1210 and the width d of the lower part of the pattern part 1210. As a result, it is a result of experiment whether or not an image bleeding phenomenon is reduced compared to a plasma display panel in which an external light blocking sheet having a flat pattern portion at the bottom is disposed.

Depth of groove (a) Bottom width of pattern part (d) Reduced bleeding 0.5 μm 27 ㎛ × 1.0 μm 27 ㎛ × 1.5 μm 27 ㎛ ○ 2.0 μm 27 ㎛ ○ 2.5 μm 27 ㎛ ○ 3.0 μm 27 ㎛ ○ 3.5 ㎛ 27 ㎛ ○ 4.0 μm 27 ㎛ ○ 4.5㎛ 27 ㎛ ○ 5.0㎛ 27 ㎛ ○ 5.5㎛ 27 ㎛ ○ 6.0 μm 27 ㎛ ○ 6.5㎛ 27 ㎛ ○ 7.0㎛ 27 ㎛ ○ 7.5㎛ 27 ㎛ × 8.0㎛ 27 ㎛ × 9.0 μm 27 ㎛ × 9.5 ㎛ 27 ㎛ ×

As shown in Table 1, when the depth (a) of the groove formed in the lower end of the pattern portion 1210 is 1.5㎛ to 7.0㎛, it is possible to reduce the blurring phenomenon of the display image to improve the sharpness of the image.

In addition, considering the prevention of damage to the pattern portion 1210 due to external impact and the ease of forming the pattern portion 1210, the depth a of the groove formed at the lower end of the pattern portion 1210 is 2 μm to 5 μm. It is preferable.

As described with reference to FIG. 7, when the bottom width d of the pattern portion 1210 is 18 μm to 35 μm, the aperture ratio for panel light emission may be secured and the external light blocking efficiency may be maximized. The bottom width (d) is preferably 3.6 times to 17.5 times the depth (a) of the groove formed in the bottom of the pattern portion 1210.

On the other hand, when the height c of the pattern portion 1210 is 80 μm to 170 μm, an inclined surface slope capable of effectively absorbing external light and reflecting panel light can be formed, so that the height c of the pattern portion 1210 is increased. The depth of the groove formed in the lower end of the pattern portion 1210 is preferably 16 times to 85 times.

In addition, when the thickness (b) of the external light blocking sheet is 100 μm to 180 μm, smooth transmission of panel light and effective absorption and blocking of external light can be achieved, and the firmness of the sheet can be secured, and thus the thickness (b) of the external light blocking sheet ) Is preferably 20 to 90 times the depth (a) of the groove formed in the lower end of the pattern portion 1210.

Referring to FIG. 25, the pattern portion 1230 may have a trapezoidal shape, and in this case, the width e of the upper end is preferably smaller than the width d of the lower end. In addition, when the width e of the upper end of the pattern portion 1230 is 10 μm or less, an inclined surface slope capable of effectively absorbing external light and reflecting panel light may be formed in relation to the lower width d. Even in this case, the relationship between the depth a of the groove formed in the lower end of the pattern part 1230 and the lower width d of the pattern part 1230 may be the same as described with reference to FIG. 24.

FIG. 26 is a cross-sectional view showing the structure of the external light blocking sheet in order to explain the relationship between the thickness of the external light blocking sheet and the height of the pattern portion.

Referring to FIG. 26, the thickness T of the external light blocking sheet is 100 μm to 180 μm to secure the robustness of the external light blocking sheet including the pattern portion and to secure the transmittance of visible light emitted from the panel to display an image. Is preferably.

When the height h of the pattern portion provided in the external light shielding sheet is 80 μm to 170 μm, the pattern part is most easily manufactured, and an appropriate opening ratio of the external light blocking sheet can be ensured, and the external light blocking effect and the light emitted from the panel The reflection effect of the light can be maximized.

The height h of the pattern portion may vary depending on the thickness T of the external light shielding sheet. In general, external light incident on the panel and affecting bright room contrast is mainly located above the position of the panel. Therefore, in order to effectively block external light incident on the panel even with a predetermined angle of incidence θ, the ratio of the height h of the pattern portion to the thickness T of the external light blocking sheet preferably has a value within a certain range.

As the height (h) of the pattern portion increases, the thickness of the base portion of the upper portion of the pattern portion may become thinner, and insulation breakage may occur. It may not be blocked properly.

Table 2 below shows the results of experiments of insulation breakdown and external light blocking effects of the external light blocking sheet according to the thickness (T) of the external light blocking sheet and the height (h) of the pattern portion.

Sheet thickness (T) Pattern height (h) Dielectric breakdown Exterior light blocking 120 μm 120 μm ○ ○ 120 μm 115 ㎛ △ ○ 120 μm 110 ㎛ × ○ 120 μm 105㎛ × ○ 120 μm 100 μm × ○ 120 μm 95 ㎛ × ○ 120 μm 90 μm × ○ 120 μm 85 μm × △ 120 μm 80㎛ × △ 120 μm 75 μm × △ 120 μm 70 ㎛ × △ 120 μm 65 μm × △ 120 μm 60㎛ × △ 120 μm 55 μm × △ 120 μm 50 μm × ×

Referring to Table 2, when the thickness T of the external light shielding sheet is 120 μm, when the height h of the pattern part is formed to be 115 μm or more, there is a risk that the pattern part is insulated and destroyed, thereby increasing the defective rate of the product. If the height h of the pattern portion is formed to be 115 μm or less, there is no fear that the pattern portion will be insulated and broken, thereby reducing the defective rate of the external light shielding sheet. However, when the height of the pattern portion is formed to be 85 μm or less, the efficiency of blocking external light by the pattern portion may be reduced, and when formed to 60 μm or less, external light may be incident on the panel. Accordingly, when the height h of the pattern portion is 90 μm to 110 μm, the external light blocking efficiency of the external light shielding sheet may be increased and the defective rate may be reduced.

In addition, when the thickness T of the external light shielding sheet is 1.01 to 2.25 times the height of the pattern portion, insulation breakdown of the upper portion of the pattern portion may be prevented, and external light may be prevented from entering the panel. In addition, in order to prevent dielectric breakdown and external light incident on the panel, and to increase the amount of reflection of light emitted from the panel and to secure a viewing angle, the thickness T of the external light shielding sheet is 1.01 times to 1.5 times the height of the pattern portion. It may be a boat.

Table 3 below shows the results of experiments on whether moiré occurred and external light blocking effect according to the ratio of the width of the bottom of the pattern portion of the external light blocking sheet to the width of the bus electrode formed on the upper substrate of the panel. If

Bottom width of pattern part / Bus electrode width Moire Exterior light blocking 0.10 △ × 0.15 △ × 0.20 × △ 0.25 × ○ 0.30 × ○ 0.35 × ○ 0.40 × ○ 0.45 △ ○ 0.50 △ ○ 0.55 ○ ○ 0.60 ○ ○

Referring to Table 3, when the width of the bottom of the pattern portion is 0.2 times to 0.5 times the width of the bus electrode, it is possible to reduce the moiré phenomenon and at the same time reduce the external light incident on the panel. In addition, in order to prevent moiré phenomenon and effectively block external light, and to secure an aperture ratio for emitting panel light, the width of the lower end of the pattern portion is preferably 0.25 times to 0.4 times the width of the bus electrode.

Table 4 below shows the results of experiments on the occurrence of moiré phenomenon and external light blocking effect according to the ratio of the width of the bottom of the pattern portion of the external light blocking sheet to the width of the vertical partition formed on the lower substrate of the panel. If

Width of pattern bottom / width of vertical bulkhead Moire Exterior light blocking 0.10 ○ × 0.15 △ × 0.20 △ × 0.25 △ × 0.30 × △ 0.35 × △ 0.40 × ○ 0.45 × ○ 0.50 × ○ 0.55 × ○ 0.60 × ○ 0.65 × ○ 0.70 △ ○ 0.75 △ ○ 0.80 △ ○ 0.85 ○ ○ 0.90 ○ ○

Referring to Table 4, when the bottom width of the pattern portion is 0.3 times to 0.8 times the top width of the vertical partition wall, it is possible to reduce the moiré phenomenon and at the same time reduce the external light incident on the panel. In addition, in order to prevent moiré phenomenon and effectively block external light, and to secure an aperture ratio for emitting panel light, it is preferable that the bottom width of the pattern portion is 0.4 times to 0.65 times the top width of the vertical partition wall.

27 to 30 are sectional views showing embodiments of the structure of the filter according to the present invention. The filter formed on the front surface of the plasma display panel includes an AR / NIR sheet, an EMI shield sheet, an external light shield sheet, and an optical sheet. And the like.

Referring to FIGS. 27 and 28, the AR / NIR sheet 1310 is an AR having a function of reducing glare by preventing reflection of light incident from the outside on the front surface of the base sheet 1313 made of a transparent plastic material. (Anti-Reflection) layer 1311 is attached to the rear, shielding the near infrared rays emitted from the panel to the NIR (Near Infrared) shielding sheet (1312) so that signals transmitted using infrared rays such as a remote control can be normally transmitted. Is attached.

The EMI shield sheet 1320 has an EMI shield sheet 1321 attached to a front surface of the base sheet 1322 made of a transparent plastic material to shield electromagnetic interference (EMI) from being emitted from the panel to the outside. . In this case, the EMI shield sheet 1321 is typically formed of a mesh structure using a conductive material, and the ratio of the EMI shield sheet 1320 without an image to be smoothly grounded is achieved. The conductive material is entirely coated on the effective display area.

Typically, the external light source is most often present at the top of the observer's head, indoors or outdoors. The external light blocking sheet 1330 is attached to effectively block the external light so that the black image of the plasma display panel can be darker.

The adhesive 1340 forms a layer between the AR / NIR sheet 1310, the EMI shielding sheet 1320, and the external light shielding sheet 1330, and thus, the sheets 1310, 1320, 1330, and the filter 1300. ) To be firmly attached to the front of the panel. In addition, the material of the base sheet included between each of the sheets 1310, 1320, and 1330 may preferably use substantially the same material in consideration of the ease of fabrication of the filter 1300.

Meanwhile, in FIG. 27, the AR / NIR sheet 1310, the EMI shielding sheet 1320, and the external light shielding sheet 1330 are stacked in this order. As illustrated in FIG. 28, the AR / NIR sheet 1310 and the external light blocking are shown. As the sheet 1330 and the EMI shielding sheet 1320 may be stacked in this order, 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 1310, 1320, 1330 may be omitted.

29 and 30, the filter 1400 formed on the front of the panel may further include an optical sheet 1420 in addition to the AR / NIR sheet 1410, the EMI shield sheet 1430, and the external light shield sheet 1440. It may include. The optical sheet 1420 improves the color temperature and luminance characteristics of the light incident from the panel, and the optical layer 1421 formed of a predetermined dye and an adhesive is laminated on the front or rear surface of the base sheet 1422 made of a transparent plastic material. do.

At least one of the basesheets shown in FIGS. 27 to 30 may be omitted, and any one of the basesheets may be made of hard glass, not plastic, to protect the panel. You can. The glass is preferably formed spaced apart from the panel at a predetermined interval.

In addition, the filter according to the present invention may further include a diffusion sheet. The diffusion sheet serves to diffuse the incident light so that the light maintains uniform brightness. Accordingly, the diffusion sheet can uniformly diffuse the light emitted from the panel 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 can condense light in the direction corresponding to the vertical viewing angle to make the front luminance uniform and at the same time improve antistatic property.

The diffusion sheet may be a transmissive or reflective diffusion film and the like, and generally may have a form in which small glass bead grains are mixed with a base sheet of a polymer material. In addition, high purity acrylic resin (PMMA) may be used as the base sheet of the diffusion sheet, and when the high purity acrylic resin (PMMA) is used, the sheet may have a thick thickness but good heat resistance, and thus may be used in a large display device having high heat generation.

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. 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 an embodiment of a schematic cross-sectional structure of an external light blocking sheet according to the present invention.

3 to 6 are cross-sectional views showing optical characteristics according to the structure of the external light blocking sheet.

It is sectional drawing which shows 1st Example about the shape of the pattern part of an exterior light shielding sheet.

8 and 9 are views showing an embodiment of the front shape of the pattern portion formed in a line on the external light blocking sheet.

FIG. 10 is a view schematically illustrating an embodiment of a structure of a black matrix formed on an upper substrate of the panel.

11 to 14 are cross-sectional views illustrating embodiments of a structure of an overlapping portion of a partition wall and a dielectric layer according to the present invention.

15 to 19 are cross-sectional views showing second to seventh embodiments of the pattern portion shape of the external light blocking sheet.

20 to 25 are cross-sectional views illustrating embodiments of a cross-sectional shape of a pattern portion having a concave shape at its lower end and optical characteristics thereof.

It is sectional drawing for demonstrating the relationship between the space | interval between the adjacent pattern parts formed in the exterior light shielding sheet, and the height of a pattern part.

27 to 30 are cross-sectional views showing embodiments of the structure of the filter including the external light blocking sheet.

Claims (20)

An upper substrate; A dielectric layer formed on the upper substrate; Lower substrate; And a partition wall formed on the lower substrate to partition a discharge cell. And A filter formed on the upper substrate side of the panel, The filter includes a base portion; And an external light blocking sheet including a plurality of pattern portions formed on the base portion. The barrier rib may include a horizontal barrier rib formed in a direction crossing the electrode formed on the lower substrate, and an angle between an upper end of the horizontal barrier rib and an overlapping portion of the dielectric layer may form the pattern portion may be 0.5 to 20 degrees. Plasma display device. The method of claim 1, And an angle between an upper end of the horizontal partition wall and an overlapping portion of the dielectric layer with the pattern portion is 0.5 to 5 degrees. The method of claim 1, And the color of the horizontal partition wall and the dielectric layer is complementary. The method of claim 1, The thickness of the external light shielding sheet is a plasma display device, characterized in that 1.01 times to 2.25 times the height of the pattern portion. The method of claim 1, And a refractive index of the pattern portion is 0.3 times or more and less than 1 times the refractive index of the base portion. The method of claim 1, And the refractive index of the pattern portion is greater than the refractive index of the base portion, and the difference between the refractive index of the pattern portion and the refractive index of the base portion is 0.05 to 0.3. The method of claim 1, And the pattern portion is disposed such that an upper end having a smaller width is further adjacent to the panel. An upper substrate; A dielectric layer formed on the upper substrate; Lower substrate; And a partition wall formed on the lower substrate to partition a discharge cell. And A filter formed on the upper substrate side of the panel, The filter includes a base portion; And an external light blocking sheet including a plurality of pattern portions formed on the base portion. The partition wall may include a horizontal partition wall formed in a direction crossing the electrode formed on the lower substrate, and a width of a portion where the upper end of the horizontal partition wall overlaps the dielectric layer is 1.3 to 5 times the width of the lower end of the pattern portion. Plasma display device. The method of claim 8, The pattern portion includes a top and a bottom wider than the top, The width of the overlapping portion is a plasma display device, characterized in that 2.5 to 3.5 times the width of the bottom of the pattern portion. The method of claim 8, And the color of the horizontal partition wall and the dielectric layer is complementary. The method of claim 8, The pattern portion includes a top and a bottom wider than the top, Plasma display device, characterized in that the bottom width of the pattern portion is 18 to 35㎛. The method of claim 8, The pattern portion includes a top and a bottom wider than the top, And a spacing between the lower ends of the two adjacent pattern parts is 1.1 to 5 times the width of the lower part of the pattern part. The method of claim 8, And the refractive index of the pattern portion is greater than the refractive index of the base portion, and the difference between the refractive index of the pattern portion and the refractive index of the base portion is 0.05 to 0.3. The method of claim 8, And the pattern portion is disposed such that an upper end having a smaller width is further adjacent to the panel. An upper substrate; A dielectric layer formed on the upper substrate; Lower substrate; And a partition wall formed on the lower substrate to partition a discharge cell. And A filter formed on the upper substrate side of the panel, The filter includes a base portion; And an external light blocking sheet including a plurality of pattern portions formed on the base portion, wherein the pattern portion includes an upper end and a lower end wider than the upper end. The barrier rib includes a plurality of horizontal barrier ribs formed in a direction crossing the electrodes formed on the lower substrate, and a gap between an upper portion of the horizontal barrier rib and two overlapping portions adjacent to each other among overlapping portions of the dielectric layer is adjacent to each other. Plasma display device, characterized in that 6 to 20 times the interval between the bottom. The method of claim 15, And a spacing between the two overlapping portions adjacent to each other is 10 to 17.5 times the spacing between the lower ends of the pattern portions adjacent to each other. The method of claim 15, The interval between the lower end of the pattern portion adjacent to each other is a plasma display device, characterized in that 40㎛ to 90㎛. The method of claim 15, And the color of the horizontal partition wall and the dielectric layer is complementary. The method of claim 15, And the refractive index of the pattern portion is greater than the refractive index of the base portion, and the difference between the refractive index of the pattern portion and the refractive index of the base portion is 0.05 to 0.3. The method of claim 15, And the pattern portion is disposed such that an upper end having a smaller width is further adjacent to the panel.

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