KR101195848B1 - Optical filter for display device and display device having the same - Google Patents

Abstract

The present invention provides an optical filter for a display device, comprising: a background layer forming a layer, a color shift reduction pattern formed to have a thickness on the background layer, and a light reflection formed behind the color shift reduction pattern to reflect light backward; It provides an optical filter for a display device comprising a patch. The color shift reduction pattern may include at least one of a color light absorbing material and a light diffusing material. The color light absorbing material may include a green wavelength absorbing material absorbing a green wavelength of 510 ~ 560nm. The color light absorbing material may further include a cyan wavelength absorbing material absorbing cyan wavelength of 480 ~ 510nm and an orange wavelength absorbing material absorbing orange wavelength of 570 ~ 600nm. The color light absorbing material may further include a black material. The light diffusing material may include light diffusing beads. The color shift reduction pattern may have a plurality of divided regions, and at least one of the plurality of divided regions may have at least one of a light absorption rate and a light diffusion rate. The first divided area may be formed in front of or behind the second divided area, or may be formed to be spaced apart from each other.

Description

Optical filter for display device and display device having the same {OPTICAL FILTER FOR DISPLAY DEVICE AND DISPLAY DEVICE HAVING THE SAME}

The present invention relates to an optical filter for a display device and a display device having the same, and more particularly, to an optical filter for a display device having a color shift reduction pattern and a display device having the same.

As the modern society becomes highly informational, image display-related components and devices are remarkably advanced and widespread. Among them, display apparatuses for displaying images are widely used as television apparatuses, monitor apparatuses for personal computers, and the like, and are being enlarged and thinned.

In general, a liquid crystal display (LCD) is a flat panel display that displays an image using liquid crystal, and is thinner and lighter than other display devices, and has a low driving voltage and low power consumption. have. Therefore, it is widely used throughout the industry.

1 is a conceptual diagram conceptually showing the basic structure and driving principle of the LCD 100.

For example, the conventional VA mode LCD is attached so that the optical axes of the two polarizing films 110 and 120 are perpendicular to each other. The liquid crystal molecules 150 exhibiting birefringence are inserted and arranged between the two transparent substrates 130 coated with the transparent electrode 140. When the electric field is applied by the driving power supply unit 180, the liquid crystal molecules are arranged to move perpendicular to the electric field.

The light emitted from the backlight unit becomes linearly polarized light after passing through the first polarizing film 120.

When the power source is off as shown on the left side of FIG. 1, the liquid crystal is vertically aligned with respect to the substrate. Therefore, the liquid crystal does not change the polarization state of light. As a result, the linearly polarized light is maintained as it is, thereby preventing the first polarizing film 120 from passing through the second polarizing film 110 perpendicular to the optical axis.

On the other hand, in the on state, as shown in the right side of FIG. 1, the liquid crystal is horizontally aligned between the optical axes of the two orthogonal polarizing films 110 and 120 in a direction parallel to the substrate by an electric field. Therefore, the linearly polarized light through the first polarizing film passes through the second polarizing film by changing to a linearly polarized, circularly or elliptically polarized state in which the polarization state is rotated 90 degrees immediately before reaching the second polarizing film while passing through the liquid crystal molecules. Done. By adjusting the intensity of the electric field, the alignment angle of the liquid crystal is gradually changed from the vertical alignment to the horizontal direction, and the intensity of the emitted light can be adjusted.

2 is a conceptual diagram illustrating alignment states and light transmittances of liquid crystals according to viewing angles.

When the liquid crystal molecules are arranged in a predetermined direction in the pixel 220, the arrangement state is different depending on the viewing angle.

When viewed from the front side in the right direction 210, the arrangement state of the liquid crystal molecules appears to be almost horizontally aligned 212, and the screen appears relatively bright. When viewed from the front of the screen 230, the arrangement state 232 of the liquid crystal molecules looks the same as the arrangement of the liquid crystal molecules in the pixel 220. When viewed from the front in the left direction 250, the arrangement state of the liquid crystal molecules appears in the vertical alignment 252, and the screen appears relatively dark.

Therefore, the LCD generates light intensity and color change according to the change in the viewing angle, and the viewing angle is greatly limited compared to the self-luminous display. Therefore, much research has been conducted for improving the viewing angle.

3 is a conceptual diagram illustrating an example of the prior art for improving the contrast ratio change and color shift according to the viewing angle.

Referring to FIG. 3, the pixel is divided into two partial pixels, that is, the first pixel portion 320 and the second pixel portion 340 so that the liquid crystal arrangement of each pixel portion is symmetrical to each other. According to the viewing direction, the arrangement of the liquid crystals in the first pixel unit 320 and the arrangement of the liquid crystals in the second pixel unit 340 are simultaneously seen, and the intensity of light visible to the viewer is determined by the light of each pixel unit. It is the sum of the strengths of.

That is, when viewed from the front side in the right direction 310, the liquid crystal of the first pixel portion 320 is shown as the horizontal alignment 312 and the liquid crystal of the second pixel portion 340 is shown as the vertical alignment 314. The screen may be made bright by the one pixel unit 320. Similarly, when viewed from the front in the left direction 350, the liquid crystal of the first pixel portion 320 is shown in the vertical alignment 352, and the liquid crystal of the second pixel portion 340 is shown in the horizontal alignment 354. By the two pixel unit 340, the screen can be seen brightly. When viewed from the front (330) is the same as the arrangement state of each pixel portion. Accordingly, the brightness of the screen when viewed by the viewer becomes the same or similar as the viewing angle changes, and becomes symmetric about the vertical direction with respect to the screen. Therefore, the change in contrast ratio and the degree of color change according to the change of viewing angle can be improved.

4 is a conceptual diagram illustrating another example of the related art for improving the contrast ratio change and color shift according to the viewing angle.

Referring to FIG. 4, an optical film 420 having a birefringence characteristic, the characteristic of which is the same as that of the liquid crystal molecules in the pixel 440 of the LCD panel, and symmetrical with the arrangement state of the liquid crystal molecules is added. Due to the arrangement state of the liquid crystal in the pixel 440 and the birefringence characteristic of the optical film 420 according to the viewing direction, the light intensity seen by the viewer is the sum of the light intensities.

That is, when viewed from the front to the right direction 410, the liquid crystal in the pixel 440 is shown in the horizontal alignment 414, the virtual liquid crystal by the optical film 420 is shown in the vertical alignment 412, the light intensity is Each sum. Similarly, when viewed from the front in the left direction 450, the liquid crystal in the pixel 440 is shown in the vertical alignment 454 and the virtual liquid crystal by the optical film 420 is shown in the horizontal alignment 452, the light intensity is Each sum. In the front view 430, the arrangement state of the liquid crystal molecules in the pixel 440 and the birefringent arrangement state of the optical film 420 appear to be the same (432 and 434).

However, even with the technique of FIG. 3 and FIG. 4, there is still a color shift according to the viewing angle, which causes a color change as the viewing angle increases.

However, even with the above technique, as shown in FIG. 5, there is still a color shift according to the viewing angle, and thus there is a problem that a color change occurs as the viewing angle increases.

An object of the present invention is to provide an optical filter and a display device having the same that can improve the color shift phenomenon according to the increased viewing angle.

In addition, an object of the present invention to provide an optical filter and a display device having the same that can improve the transmittance.

The present invention also provides an optical filter capable of preventing the front color of the display image from being changed by the color light absorbing material and a display device having the same.

The technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, the present invention provides an optical filter for a display device, comprising a color shift reducing pattern formed to have a layered background layer and a thickness on the background layer, and formed behind the color shift reduction pattern. It provides an optical filter for a display device comprising a light reflection patch for reflecting light backward.

The color shift reduction pattern may include at least one of a color light absorbing material and a light diffusing material.

The color light absorbing material may include a green wavelength absorbing material absorbing a green wavelength of 510 ~ 560nm. The color light absorbing material may further include a cyan wavelength absorbing material absorbing cyan wavelength of 480 ~ 510nm and an orange wavelength absorbing material absorbing orange wavelength of 570 ~ 600nm. The color light absorbing material may further include a black material.

The light diffusing material may include light diffusing beads.

The color shift reduction pattern may have a plurality of divided regions, and at least one of the plurality of divided regions may have at least one of a light absorption rate and a light diffusion rate.

The first divided area may be formed in front of or behind the second divided area, or may be formed to be spaced apart from each other.

According to the above configuration, the present invention can achieve the above object.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Comparative Example

6 is a perspective view showing an optical filter according to a comparative embodiment of the present invention.

As shown, the optical filter of FIG. 6 includes a background layer 10 and a color shift reduction pattern 20.

The color shift reduction pattern 20 of FIG. 6 includes a color light absorbing material. The color light absorbing material includes a green wavelength absorbing material that absorbs a green wavelength of 510 to 560 nm. In addition, the color light absorbing material may further include cyan wavelength absorbing material absorbing cyan wavelength of 480 ~ 510nm and orange wavelength absorbing material absorbing orange wavelength of 570 ~ 600nm. In addition, the color light absorbing material may further include a black material such as carbon black.

The background layer 10 or the backing layer 30 may include a color correction material that changes or adjusts the color balance by reducing or adjusting the amounts of red (R), green (G), and blue (G).

When the light from the front of the display passes through the optical filter for the display device, the color of the image of the display is changed by the color shift reduction pattern, so that the wavelength region or orange drawn with the color correction pigment in the background layer 10 or the backing layer 30 is changed. A color that absorbs wavelengths other than the wavelength and cyan wavelengths, for example, green complementary wavelength absorbing materials such as red and blue wavelength absorbing materials, may be colored to be close to the original color from the front. You can correct it. It is not provided as a separate layer or film, and is formed by adding a color correction material to the background layer 10 or the backing layer 30, thereby simplifying the structure of the optical filter and shortening the manufacturing process.

Of course, the color correction material may be included in the adhesive layer in addition to the background layer 10 or the backing layer 30, and may also be included in other functional films.

7 and 8 are reference views for explaining the color light absorbing material.

An optical filter filled with a green wavelength absorbing material, etc., in the color shift reduction pattern 20 was mounted on an LCD TV, and color coordinates at the front and viewing angles of 60 degrees were compared on a full white screen.

When the green wavelength absorbing material is filled in the color shift reduction pattern 20 of the wedge cross-section, the color of the green wavelength absorbing material becomes stronger as the viewing angle increases, and the color coordinates move toward the pink region in the CIE 1976 UCS color coordinate system u'v '. . In addition, in the case where i) carbon black or ii) cyan wavelength absorber and orange wavelength absorber are filled together with the green wavelength absorbing material, the color coordinates move from the color coordinate system u'v 'toward the purple pink area.

In the color coordinate system u'v ', it is preferable that the value of Δv' / Δu ', that is, (v' ₆₀ -v ' ₀ ) / (u' ₆₀ -u ' ₀ ) is tan (-15 °) to tan (45 °). Do. (Here, u _'0, v' ₀ are color coordinate value a and u _'60, v' ₆₀ measured at a viewing angle of 0 degree is a color coordinate values measured at a viewing angle of 60 °)

Specifically, when only the green wavelength absorbing material is filled in the color shift reduction pattern 20, the slope of the color coordinate change when the viewing angle is 60 degrees from the front of the color coordinate system u'v 'is 15 to 45 degrees. When the carbon black and carbon black are filled together, the slope of the color coordinate change when the viewing angle is 60 degrees compared to the front is -15 to 15 degrees, and when the green wavelength absorber, cyan wavelength absorber, and orange wavelength absorber are filled together, It is preferable that the inclination of the color coordinate change at the viewing angle of 60 degrees is -15 to 15 degrees.

FIG. 9 is a view illustrating color shifts of 13 mixed colors according to a viewing angle in the LCD TV equipped with the optical filter of FIG. 6.

6 wt% of the green wavelength absorbing material (pink dye) was prepared in the color shift reduction pattern 20 of FIG. 6 to obtain a color shift result as shown in FIG. 9.

Embodiment of the Invention

10 is a cross-sectional view showing an optical filter according to a first embodiment of the present invention.

The optical filter of the present invention is typically provided in front of the display panel of the display device, but may be provided between the display panel and the backlight unit.

The optical filter includes a background layer 10, a color shift reduction pattern 20, and a light reflection patch 40.

The background layer 10 is formed by layering a material that transmits light. The background layer 10 may be made of an ultraviolet curable resin.

The color shift reduction pattern 20 is formed on the background layer 10 to have a predetermined thickness.

The color shift reduction pattern may be any one of a wedge cross-section stripe pattern, a wedge cross-section wave pattern, a wedge cross-section matrix pattern, a wedge cross-section honeycomb pattern, a cross-section stripe pattern, a cross-section wave pattern, a cross-section matrix pattern, and a cross-section honeycomb pattern. .

Also, for example, the stripe pattern may have various patterns such as a horizontal stripe pattern, a vertical stripe pattern, and the like. When it is formed in the horizontal direction, it is effective for vertical viewing angle compensation, and when it is formed in the vertical direction, it is effective for right and left viewing angle compensation.

In addition, by arranging the battery to have a predetermined bias angle with respect to the horizontal direction or the vertical direction, the moiré phenomenon can be effectively prevented.

The color shift reduction pattern may be formed so that the bottom surface thereof faces the viewer, may be formed to face the display panel, or may be formed on both sides of the background layer 10.

10 illustrates an embodiment in which the color shift reduction pattern is intaglio with respect to the background layer 10, but is not necessarily limited thereto and may be embossed.

The color shift reduction pattern includes at least one of a color light absorbing material and a light diffusing material.

The color light absorbing material includes i) green wavelength absorbing material, or ii) cyan wavelength absorbing material and orange wavelength absorbing material together with green wavelength absorbing material, or ii) green wavelength absorbing material, cyan wavelength absorbing material and orange wavelength absorbing material. The material may include a black material such as carbon black, or iv) the green wavelength absorbing material may include a black material such as carbon black.

Color shift reduction pattern including green wavelength absorbing material

In general, the display industry evaluates 13 mixed colors (White, Red, Blue, Green, Skin, Sony Red, Sony Blue, Sony Green, Cyan, Purple, Yellow, Moderate Red, and Purplish Blue). .

When the white light emitted from the display panel is emitted at a high gradation, the luminance decreases in all wavelength regions as the viewing angle increases, and the blue wavelength region decreases relatively quickly, while all wavelengths are increased as the viewing angle increases when emitted at low gradations. The luminance increases in the region, and the green wavelength region increases relatively quickly.

Therefore, by filling the green wavelength absorbing material in the color shift reduction pattern, the absorption of light from the display panel increases gradually as the viewing angle of the light emitted from the display panel increases and the green wavelength range of 510 to 560 nm is increased. Since the absorption of light is increased relatively, the color shift due to the increase in the viewing angle can be minimized by reducing the difference in the relative luminance of the RGB due to the change in the viewing angle and the gray level, which causes the color shift.

As the green wavelength absorbing material, any one of an inorganic material and an organic material capable of absorbing light having a green wavelength of 510 to 560 nm may be used, and a pink pigment is preferably used. As the green wavelength absorbing material, any material that can absorb light of the green wavelength may be used in addition to the pink pigment.

Color shift reduction pattern including green wavelength absorber + cyan wavelength absorber + orange wavelength absorber

11 is a graph showing emission spectra of LEDs and CCFL backlights.

As shown, in contrast to LEDs (shown on the left in FIG. 11), CCFL backlights (shown on the right in FIG. 11) have strong peaks in the cyan wavelength region near 490 nm and orange wavelength region near 590 nm. (peak) is present.

These peaks in the cyan and orange wavelength ranges cause color reproduction areas and worsen color shift.

12 is a diagram illustrating color shifts according to viewing angles of LEDs and CCFL backlights.

As shown, the color shift results of the LCD composed of LEDs (shown on the left in FIG. 12) and backlights (shown on the right in FIG. 12) of the CCFLs indicate that the CCFLs are not good.

Therefore, when the peaks of the cyan wavelength region and the orange wavelength region which adversely affect the color shift according to the viewing angle are absorbed more as the viewing angle increases, the mixed color change according to the viewing angle may be further minimized.

In order to play this role, the color shift reduction pattern may include not only the green wavelength absorbing material capable of absorbing the green wavelength region of 510-560 nm, but also the cyan wavelength absorbing material of 480-510 nm and the orange wavelength absorbing material of 570-600 nm. . As a result, the green wavelength region of the light emitted from the display panel is absorbed more as the viewing angle increases, and the peak angles of the cyan wavelength region and the orange wavelength region which increase the viewing angle adversely affect the color shift according to the viewing angle in the spectrum of the LCD are increased. Absorbs more along. Through this, it is possible to further increase the viewing angle improvement effect by minimizing the color change according to the increase of the viewing angle and minimizing the color change in all the mixed colors including the blue mixed color series and the red mixed color series.

Color shift reduction pattern including black material

The color shift may be improved by additionally including a black material such as carbon black in the color shift reduction pattern.

13 and 14 illustrate changes in luminance and normalized luminance according to viewing angles and gray levels of a Bare LCD.

In the high gray level, the luminance decreases as the viewing angle increases. However, as shown in FIGS. 13 and 14, the phenomenon that the brightness increases as the viewing angle increases in the low gray level causes the color shift to worsen. Therefore, as the viewing angle increases, the color shift can be improved by allowing more light to be emitted from the display panel to be absorbed so that the luminance decreases according to the viewing angle regardless of the gray level.

A light reflection patch 40 is formed behind the color shift reduction pattern to reflect the light backward. As shown in FIG. 15, the light reflection patch reflects light incident on the color shift reduction pattern among the light emitted from the display panel, and the reflected light is reflected back from the display panel or the tempered glass and emitted forward. Helps improve transmittance In addition, since the color light absorbing material reflects the light incident on the filled color shift reduction pattern, it is possible to prevent the display image color from being changed by the color light absorbing material. In order to compensate for the frontal color change by the color light absorbing material, a material that transmits only the absorption wavelength of the color light absorbing material is included in the background layer, the backing layer, or the like, or a separate layer including a material that transmits only the absorption wavelength of the color light absorbing material. Since it is not necessary to form a, it is possible to further improve the transmittance.

The light reflection patch 40 may be formed by filling metal particles. For example, it may be formed by filling a mixture of Ag particles and a resin (Ag Paste).

In addition, the optical filter may include a backing layer 30 supporting the background layer 10, as shown in FIG. 10. However, depending on the embodiment, the backing layer can be omitted.

As for the backing layer 30, the transparent resin film which has ultraviolet permeability is preferable. As the material of the backing layer 30, for example, polyethylene terephthalate (PET), polycarbonate (PC), polyvinyl chloride (PVC), or the like may be used.

15 is a schematic cross-sectional view of an optical filter according to a second exemplary embodiment of the present invention.

As illustrated, the optical filter of the present invention may include a tempered glass transparent substrate 50.

16 is a schematic cross-sectional view of an optical filter according to a third exemplary embodiment of the present invention.

As shown, the color shift reduction pattern may include a light diffusing material.

The light diffusing material improves color shift by inducing color mixing by spreading the light emitted from the display panel more evenly as the viewing angle increases.

As the light diffusing material, light diffusing particles such as light diffusing beads may be used.

Typically, the color light absorbing material and the light diffusing material are mixed in the transparent polymer resin, and included in the color shift reduction pattern, wherein the refractive index of the light diffusing particles is preferably higher than the refractive index of the polymer resin, and is preferably at least 0.01. Light diffusion effect can be obtained. The light diffusing particles are preferably white which can diffuse light of all wavelengths into particles having an average diameter of 0.1 μm or more. However, the present invention is not limited thereto.

The light diffusing particles may have two or more sizes and refractive indices, and may control suitable optical properties by using the material, refractive index, size, and particle size distribution of the light diffusing particles.

The light diffusing particles may include at least one of oxides such as PMMA, vinyl chloride, acrylic resin, PC-based, PET-based, PE-based, PS-based, PP-based, PI-based resin, glass, and silica TiO ₂ .

17 and 18 are cross-sectional views schematically showing optical filters according to the fourth and fifth embodiments of the present invention, respectively.

The color shift reduction pattern may have a plurality of divided regions. Here, at least two regions have different light absorption rates and / or light diffusion rates.

To this end, the at least two regions may include different color light absorbing materials and / or light diffusing materials. For example, different types of color light absorbing materials may be included in the first divided area 21 and the second divided area 23 so that the light absorption rate may be varied.

As another example, the at least two regions may include a color light absorbing material and / or a light diffusing material in different content ratios. Here, the content ratio also includes the case of content ratio 0.

For example, assuming that the color shift reduction pattern has two divided regions of the first divided region 21 and the second divided region 23, i) the first divided region as shown in FIG. 17. Reference numeral 21 denotes a color light absorbing material, the second division area 23 includes a light diffusing material, or ii) the first division area includes both a color light absorbing material and a light diffusing material, and the second division area Various modifications are possible, including only one of the color light absorbing material and the light diffusing material, or iii) the first and second split areas may include both the color light absorbing material and the light diffusing material.

Each of the divided regions may have various arrangements, but FIGS. 17 and 18 illustrate embodiments in which the first divided region 21 is formed at the front or the rear of the second divided region 23.

In the method for forming the optical filter of FIG. 17, after the ultraviolet curable resin is applied to one surface of the backing layer 30, the intaglio grooves are formed in the ultraviolet curable resin using a roll for pattern molding. Thereafter, the ultraviolet curable resin is irradiated with ultraviolet rays to finally complete the background layer 10 on which the wedge cross-sectional recesses are formed.

However, the present invention is not limited to this, and the intaglio groove of the background layer can be formed by various methods such as a heat press method using a thermoplastic resin, an injection molding method by filling a thermoplastic resin or a thermosetting resin, and molding.

After filling the intaglio groove with a mixture of color light absorbing material, an ultraviolet curable polymer resin, a solvent, and the like, and evaporating the solvent by drying, a portion of the intaglio groove is filled. Thereafter, ultraviolet rays are cured by irradiation.

Then, after filling the intaglio groove with a mixture made of a light diffusing material, an ultraviolet curable polymer resin, and the like, the ultraviolet rays are irradiated to complete the color shift reduction pattern. At this time, the filling amount of the mixture should be determined in consideration of the fact that the light reflecting material should be filled in the recess groove in a subsequent process.

Then, the intaglio grooves are again filled with a mixture of a light reflecting material and a resin, for example, and then cured to complete the light reflecting patch.

19 is a schematic cross-sectional view of an optical filter according to a sixth exemplary embodiment of the present invention.

As shown, the plurality of divided regions may be formed to be spaced apart from each other on a vertical plane perpendicular to the optical filter.

The plurality of partitions may have various arrangements and may have a regular arrangement order. 19 illustrates an embodiment in which the first divided area and the second divided area are alternately arranged.

In the method of manufacturing the optical filter of FIG. 19, after the ultraviolet curable resin is applied to one surface of the backing layer 30, the intaglio groove is formed in the ultraviolet curable resin by using a pattern forming roll. Thereafter, the ultraviolet curable resin is irradiated with ultraviolet rays to finally complete the background layer 10 on which the wedge cross-sectional recesses are formed.

However, the present invention is not limited thereto, and the intaglio groove of the background layer can be formed by various methods such as a thermopress method using a thermoplastic resin, an injection molding method of filling a thermoplastic resin or a thermosetting resin by molding, and the like.

The engraved groove is filled with a mixture made of a light absorbing material (or a light diffusing material forming a second divided region), an ultraviolet curable resin, or the like which forms the first divided region, and then cured by irradiating with ultraviolet rays.

Then, a negative groove is formed by using a laser.

Then, the engraved groove is filled with a mixture made of a light diffusing material (or light absorbing material constituting the first divided region), an ultraviolet curable resin, or the like forming the second divided region. At this time, the filling amount of the mixture should be determined in consideration of the fact that the light reflecting material should be filled in the recess groove in a subsequent process.

Then, ultraviolet rays are irradiated to cure the ultraviolet curable resin, thereby completing the color shift reduction pattern.

Then, the intaglio grooves are again filled with a mixture of light reflecting material and resin, for example.

Then, curing is performed to complete the light reflection patch 40.

20 and 21 are cross-sectional views schematically showing optical filters according to the seventh and eighth embodiments of the present invention, respectively.

As shown, the arrangement of the first divided area 21 and the second divided area 23 may have various modifications. FIG. 20 illustrates an embodiment in which second divided regions per two first divided regions are sequentially arranged in a regular order, and FIG. 21 sequentially shows one first divided region per two second divided regions. It shows an embodiment arranged in a regular order of.

In addition, the first divided area and the second divided area may be arranged symmetrically with respect to the center of the optical filter, respectively. For example, it is possible to arrange such that the first partitions on the left and right sides of the first partition are arranged from the center, and the second to fourth partitions on the left and right sides are arranged on the second partition.

10 and 15 to 21 illustrate an embodiment in which the color shift reduction pattern is composed of two divided regions for convenience of description, but may further have three or more divided regions.

The optical filter for a display device of the present invention may be formed by stacking various functional films such as an antireflection layer, an anti-glare layer, an antifog layer, and the like, in addition to the background layer, the backing layer, and the tempered glass transparent substrate.

In the above, for convenience of description, the LCD of the display device of the present invention was described as an example, but the display device of the present invention is not necessarily limited thereto. The display device of the present invention can be variously applied to a large display device such as PDP, OLED, FED, etc. that implements RGB, a small mobile display device such as a PDA, a small game machine display window, a mobile phone display window, and a soft display device.

1 is a conceptual diagram conceptually showing the basic structure and driving principle of an LCD.

2 is a conceptual diagram illustrating alignment states and light transmittances of liquid crystals according to viewing angles.

3 is a conceptual diagram illustrating an example of the prior art for improving the contrast ratio change and color shift according to the viewing angle.

4 is a conceptual diagram illustrating another example of the related art for improving the contrast ratio change and color shift according to the viewing angle.

5 is a graph showing a color shift according to the viewing angle of the LCD without the optical filter of the present invention.

6 is a cross-sectional view showing an optical filter according to a comparative embodiment of the present invention.

7 and 8 are reference views for explaining the color light absorbing material.

FIG. 9 is a graph illustrating color shift of an LCD equipped with the optical filter of FIG. 6.

10 is a cross-sectional view showing an optical filter according to a first embodiment of the present invention.

11 and 12 are reference views for explaining the cyan wavelength absorbing material and the orange wavelength absorbing material.

13 and 14 are reference views for explaining the black material.

15 to 21 are cross-sectional views showing optical filters according to second to eighth embodiments of the present invention.

Claims (14)

As an optical filter for a display device, Layered background layers A color shift reduction pattern formed to have a thickness in the background layer; It is formed on the rear of the color shift reduction pattern and comprises a light reflection patch for reflecting light backward, The color shift reducing pattern includes a color light absorbing material including a green wavelength absorbing material absorbing a green wavelength of 510 ~ 560nm. The method of claim 1, The color shift reducing pattern further comprises a light diffusing material. delete The method of claim 1, The color light absorbing material further comprises cyan wavelength absorbing material absorbing cyan wavelength of 480 ~ 510nm and orange wavelength absorbing material absorbing orange wavelength of 570 ~ 600nm. The method of claim 1, The color light absorbing material further comprises a black material. The method of claim 5, The black material is an optical filter for a display device, characterized in that the carbon black. 3. The method of claim 2, And the light diffusing material includes a light diffusing bead. The method of claim 1, The color shift reduction pattern is an optical filter for a display device, characterized in that it comprises a resin. The method of claim 1, The color shift reduction pattern is any one of a wedge section stripe pattern, a wedge cross section wave pattern, a wedge cross section matrix pattern, a wedge cross section honeycomb pattern, a square cross section stripe pattern, a square cross section wave pattern, a square cross section matrix pattern, and a square cross section honeycomb pattern. An optical filter for display device, characterized in that. The method of claim 1, The color shift reduction pattern has a plurality of divided regions, At least two areas of the plurality of divided areas have at least one of a light absorption rate and a light diffusion rate different from each other. The method of claim 10, The color shift reduction pattern includes at least one of a color light absorbing material and a light diffusing material, The color shift reduction pattern has two divided regions of a first divided region and a second divided region, The color light absorbing material is included only in the first divided area, and the light diffusing material is included only in the second divided area. 12. The method of claim 11, And the first divided area is formed at the front or the rear of the second divided area. 12. The method of claim 11, And the first divided area and the second divided area are spaced apart from each other. A display device comprising the optical filter for display device according to any one of claims 1, 2 and 4 to 13.

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