KR102752312B1 - Polarizing plate and optical display apparatus comprising the same - Google Patents

Abstract

A polarizing plate and an optical display device including the same are provided, which comprises a first region and a second region included in an image display region, wherein the first region includes a first layer, the first region has a polarization degree of more than 0% and less than or equal to 30% and a group transmittance of 20% to 90%, and a difference in group transmittance between the first region and the second region is less than or equal to 10%.

Description

Polarizing plate and optical display apparatus including the same {POLARIZING PLATE AND OPTICAL DISPLAY APPARATUS COMPRISING THE SAME}

The present invention relates to a polarizing plate and an optical display device including the same.

Polarizing plates are included in optical display devices to display images or improve image quality. Mobile displays such as cell phones can also perform the function of taking pictures or videos by having an image sensor such as a camera.

Recently, an optical display device is being developed that places an image sensor at the bottom of a display panel without forming a hole in a polarizing plate. In this case, a portion of the polarizing plate corresponding to the image sensor must be able to perform not only the function of taking pictures or images but also the function of displaying images. Accordingly, it must be possible to implement uniform screen quality between a portion of the polarizing plate corresponding to the image sensor and a portion of the polarizing plate not corresponding to the image sensor.

Meanwhile, when taking pictures or videos using a mobile display such as a cell phone, the pictures are not taken in only one direction. That is, the mobile display is rectangular and has a long axis direction (the long side direction of the mobile display) and a short axis direction (the short side direction of the mobile display). However, depending on the user, the picture may be taken in the long axis direction, the mobile display may be rotated 90° to take the picture in the short axis direction, or the picture may be taken in any direction other than the short axis direction or the long axis direction. At this time, since one area of the polarizing plate corresponding to the image sensor has a certain degree of polarization performance, the color or clarity of the screen image may vary depending on the shooting direction. Therefore, the color or clarity of the screen image needs to be uniform regardless of the shooting direction.

The background technology of the present invention is described in Japanese Patent Publication No. 2014-081482, etc.

An object of the present invention is to provide a polarizing plate capable of making the color or clarity of a photograph or video substantially the same regardless of the shooting direction.

Another object of the present invention is to provide a polarizing plate capable of making the color or clarity of a screen substantially the same depending on the viewing direction when viewed through polarizing sunglasses.

Another object of the present invention is to provide a polarizing plate capable of minimizing the difference in screen quality between a first area where an image sensor is placed and a second area where an image sensor is not placed.

Another object of the present invention is to provide a polarizing plate having excellent reliability.

One aspect of the present invention is a polarizing plate.

1. A polarizing plate has a first region and a second region included within an image display region, the first region includes a first layer, the first region has a polarization degree of more than 0% and less than or equal to 30% and a group transmittance of 20% to 90%, and a difference in group transmittance between the first region and the second region is less than or equal to 10%.

In 2.1, the second region may have a polarization degree of 80% or more.

In 3.1-2, the polarizing plate may include a first polarizer region corresponding to the first region, a second polarizer region corresponding to the second region, and a polarizer including the first layer.

In 4.3, the first layer can be laminated on at least one surface of the first polarizer region.

In 5.3, the first polarizer region may include a polyvinyl alcohol-based film.

6.5, the first layer may have a lower group transmittance compared to the first polarizer region.

In 7.5, the first polarizing region and the laminate of the first layer may have a polarization degree of more than 0% and less than or equal to 30%, and a group transmittance of 20% to 90%.

In 8.5, the thickness of the first layer can be 1% to 20% of the thickness of the first polarizer region.

In 9.1-8, the first layer may include an organic layer, an inorganic layer, or an organic-inorganic mixed layer.

In 10.1-9, the first layer may include at least one of a dye and a pigment.

In 11.3, a protective layer may be further formed on at least one surface of the polarizer.

The optical display device of the present invention includes the polarizing plate of the present invention.

The above optical display device includes a display panel, a polarizing plate formed on an upper portion of the display panel, and an image sensor formed on a lower portion of the display panel, wherein the image sensor can be disposed on a lower portion of the first region of the polarizing plate.

The present invention provides a polarizing plate capable of making the color or clarity of a photograph or video substantially the same regardless of the shooting direction.

The present invention provides a polarizing plate capable of making the color or clarity of a screen substantially the same depending on the viewing direction when viewed through polarizing sunglasses.

The present invention provides a polarizing plate capable of minimizing the difference in screen quality between a first region where an image sensor is placed and a second region where an image sensor is not placed.

The present invention provides a polarizing plate having excellent reliability.

Figure 1 is a plan view of a polarizing plate of one embodiment of the present invention.
Figure 2 is a cross-sectional view of a polarizer of one embodiment of the present invention.
Figure 3 is a cross-sectional view of a polarizing plate according to one embodiment of the present invention.
Figure 4 is a cross-sectional view of an optical display device according to one embodiment of the present invention.

The present invention will be described in detail with reference to the attached drawings and embodiments so that a person skilled in the art can easily implement the present invention. The present invention can be implemented in various different forms and is not limited to the embodiments described herein.

In order to clearly explain the present invention in the drawings, parts that are not related to the description are omitted, and the same names are used for identical or similar components throughout the specification. The length and size of each component in the drawings are for explaining the present invention, and the present invention is not limited to the length and size of each component described in the drawings.

In this specification, “upper” and “lower” are defined based on the drawing, and depending on the viewing angle, “upper” may change to “lower” and “lower” may change to “upper.”

In this specification, “total transmittance (Ts)” and “polarization degree” each mean a value measured at a wavelength of 200 nm to 800 nm, preferably at a wavelength of 550 nm.

In this specification, with respect to the "group transmittance of the first region", the group transmittance of the first region is the same throughout the first region at the same wavelength. However, if the group transmittance is not the same throughout the first region even at the same wavelength, the group transmittance of the first region means the average group transmittance.

In this specification, with respect to the "group transmittance of the second region", the group transmittance of the second region is the same throughout the second region at the same wavelength. However, if the group transmittance is not the same throughout the second region even at the same wavelength, the group transmittance of the second region means the average group transmittance.

In this specification, "average group transmittance" means the average value of group transmittance in an area where the average group transmittance is to be measured. For example, the average group transmittance can be obtained by arbitrarily designating multiple points in an area where the average group transmittance is to be measured and obtaining the average value of group transmittance obtained at those points.

When describing a numerical range in this specification, “X to Y” means “X or more and Y or less (X≤ and ≤Y).”

The polarizing plate of the present invention has an image display area and a first area and a second area formed within the image display area. When the polarizing plate is applied to an optical display device, an area corresponding to an image sensor (e.g., a camera) in the optical display device is referred to as a first area, and an area other than the first area, i.e., an area not corresponding to the image sensor, is referred to as a second area. The first area can perform both an image or photographing function and an image display function.

The above "image display area" means an area on a screen implemented by an optical display device where an image is displayed. When a polarizing plate is applied to the optical display device, the image display area may be comprised of 90% to 100% of the polarizing plate, preferably 100%. The optical display device is described in more detail below.

The polarizing plate of the present invention can be used in the optical display device to make the color or clarity of the screen image substantially the same according to the direction even when the shooting direction is changed when taking a picture or video by an image sensor. In addition, the polarizing plate of the present invention can minimize the difference in screen quality between the first region and the second region. In addition, the polarizing plate of the present invention can provide high reliability at high temperature and high humidity.

Referring to Fig. 1, a polarizing plate according to one embodiment of the present invention will be described. Fig. 1 is a plan view of a polarizing plate according to one embodiment of the present invention.

Referring to Fig. 1, the polarizing plate has a first region (110) and a second region (120). The first region (110) and the second region (120) may be included in an image display region of an optical display device.

The first region (110) is a region corresponding to the image sensor among the image display regions of the optical display device. Although not shown in Fig. 1, when a polarizing plate is applied to the optical display device, an image sensor may be placed at the bottom of the first region (110). The first region (110) may perform an image display function when the image sensor is not used, and may perform a photo or video shooting function when the image sensor is used to take a photo or video.

The second region (120) is an area of the image display area of the optical display device that does not correspond to the image sensor. Therefore, unlike the first region, the second region (120) can only perform an image display function.

The first region (110) has a polarization degree of more than 0% and less than or equal to 30%, specifically more than 0% and less than or equal to 20%, and more specifically more than 0% and less than or equal to 15%. In the above range, when the image sensor is not used, the image display function is performed, and when taking a picture or video by the image sensor, the color or clarity of the screen image can be made substantially the same depending on the shooting direction even if the shooting direction is changed. In addition, when the optical display device is viewed with polarizing sunglasses, there is a problem that the image changes significantly depending on the viewing direction, but the polarizing plate of the present invention can solve the above-described problem even when using polarizing sunglasses.

In general, polarization and group transmittance are in a trade-off relationship. Therefore, if the polarization of the first region is significantly lowered to 30% or less, there is a problem that the group transmittance of the first region becomes very high, exceeding 90%. A group transmittance exceeding 90% significantly increases the difference in group transmittance between the first and second regions, which severely increases the difference in image brightness between the first and second regions, and may deteriorate the image quality from the image display area.

On the other hand, the first region (110) has a group transmittance of 20% to 90%, specifically 40% to 50%. Through this, the polarizing plate can minimize the difference in brightness of the image between the first region and the second region in the image display function, and also the difference in the uniformity of color and the image quality when the shooting direction is changed.

The difference in group transmittance between the first region (110) and the second region (120) is 10% or less, specifically 0% to 10%, or 0% to 5%, so that light transmittance in the first region and the second region is made uniform, thereby reducing the difference in screen quality between the first region and the second region, and also minimizing the difference in color uniformity and image quality when the shooting direction is changed.

The second region (120) has a higher polarization degree than the first region (110). In one specific example, the second region may have a polarization degree of 80% or more, for example, 90% to 100%. In the above range, the image quality in the image display area due to anti-reflection may be excellent.

The second region (12) can have a group transmittance of 20% to 90%, specifically 40% to 50%. In the above range, the image quality can be excellent.

The polarizing plate can satisfy the group transmittance of the first region and the group transmittance difference between the first region and the second region while having the polarization degree of the first region by including the first layer in the first region. The polarizing plate of the present invention is characterized by having a first region whose polarization degree is significantly lower than that of the second region while having the group transmittance at substantially the same level as that of the second region. Through this, the effects of the present invention described above can be obtained.

The first region in the polarizing plate may not include a hole formed in the polarizer. The first layer may allow the first region, which does not include a hole formed in the polarizer, to reach the above-described group transmittance.

A polarizing plate comprises a polarizer having a first polarizing region and a second polarizing region, wherein the polarizer further has a first layer laminated on the first polarizing region. The first layer is not included in the second polarizing region.

Hereinafter, a polarizing plate according to one embodiment of the present invention will be described with reference to Fig. 2. Fig. 2 is a cross-sectional view of a polarizer in the polarizing plate according to one embodiment of the present invention.

Referring to FIG. 2, the polarizer (10) includes a first polarizer region (11), a second polarizer region (12), and a first layer (20), and the first layer (20) is laminated on one surface of the first polarizer region (11). Preferably, the first layer (20) can be laminated on the viewing side of the polarizer (10), i.e., the observer side.

The first polarizer region (11) may correspond to the first region (110) of Fig. 1, and the second polarizer region (12) may correspond to the second region (120) of Fig. 1.

The first polarizer region (11) and the second polarizer region (12) are formed integrally with each other. The above “formed integrally” means that the first polarizer region is not a hole formed by physical punching or the like, so that the first polarizer region and the second polarizer region are directly connected.

The second polarizer region (12) has a higher polarization degree than the first polarizer region (11). In one specific example, the second polarizer region may have a polarization degree of 80% or more, for example, 90% to 100%. In the above range, the image quality in the image display region may be excellent due to anti-reflection.

The second polarizer region (12) can have a group transmittance of 20% to 90%, specifically 40% to 50%. In the above range, the image quality can be excellent.

The first polarizing region (11) can have a polarization degree of more than 0% and less than or equal to 30%, specifically more than 0% and less than or equal to 15%. In the above range, the polarization degree of the first region can be easily reached, thereby obtaining the above-described effect.

The first polarizer region (11) has a higher group transmittance than the first region (110). However, the group transmittance of the first region (110) may be lowered than the group transmittance of the first polarizer region (11) due to the first layer (20). For example, the group transmittance of the first polarizer region (11) may be 80% or more and 100% or less.

The first layer (20) is laminated on at least one surface of the first polarizer region (11). The first layer (20) may be laminated on one surface (upper surface) of the first polarizer region (110) or may be laminated on both surfaces (upper surface and lower surface).

The first layer (20) is formed by directly contacting the first polarizer region (11), thereby helping to thin the polarizer and improve the reliability of the polarizer due to moisture. The first polarizer region (11) is formed by light irradiation, and when external moisture penetrates into the first polarizer region (11), the dichroic material within the first polarizer region is restored to its state before the light irradiation, thereby increasing the degree of polarization. The first layer (20) can also function as a reliability improvement layer of the polarizer by blocking external moisture from penetrating into the first polarizer region, thereby improving the reliability of the polarizer.

The first layer (20) can also function as a light transmittance control layer that lowers the group transmittance of the first region (110) of Fig. 1. The first layer (20) has a lower group transmittance than the first polarizer region (11). Therefore, the first region can have a polarization degree of more than 0% and less than or equal to 30% and a group transmittance of 20% to 90%, preferably 40% to 50%.

The laminate of the first polarizing region (11) and the first layer (20) may have a polarization degree of more than 0% and less than or equal to 30%, specifically more than 0% and less than or equal to 15%. In the above range, when the image sensor is not used, the image display function is performed, and when taking a picture or video by the image sensor, the color or clarity of the screen image can be made substantially the same depending on the shooting direction even if the shooting direction is changed. In addition, when the optical display device is viewed with polarizing sunglasses, there is a problem that the image changes significantly depending on the viewing direction, but the polarizing plate of the present invention can solve the above-described problem even when using polarizing sunglasses. In addition, when the polarizing plate includes a phase difference film, an external light reflection prevention effect can also be provided.

The laminate of the first polarizing region (11) and the first layer (20) can have a group transmittance of 20% to 90%, specifically 40% to 50%. Through this, the polarizing plate can minimize the difference in brightness of the image between the first region and the second region in the image display function, and if the polarizing plate includes a phase difference film, it can also provide an effect of preventing external light reflection.

The polarizing plate of the present invention can obtain the effects of the present invention even when a protective layer is not provided on one or both sides of the polarizer by ensuring that the first polarizer region (11) and the laminate of the first layer (20) directly laminated on the first polarizer region (11) satisfy the above-described polarization degree and single layer transmittance ranges, and can improve the reliability of the polarizer even when the first polarizer region (11) is formed by light irradiation.

The first layer (20) can have a group transmittance of 20% to 90%, specifically 30% to 70%. In the above range, the group transmittance of the first region can be reached, and when a protective layer is formed on one side of the polarizer, an external light reflection prevention effect can be provided, thereby minimizing the difference in screen quality between the first region and the second region.

The first layer (20) may have a thickness of 0.1 ㎛ to 10 ㎛, specifically 0.1 ㎛ to 5 ㎛. In the above range, a thinning effect of the polarizing plate can be provided without affecting the thickness of the polarizing plate.

The thickness of the first layer (20) can be 1% to 20%, specifically 5% to 20%, of the thickness of the first polarizer region (11). In the above range, the effect of increasing group transmittance and the effect of preventing external light reflection can be provided.

The first layer (20) is not limited in its forming material or forming method as long as it can provide the above-described function. The first layer (20) can be an organic layer, an inorganic layer, or an organic-inorganic mixed layer.

In one specific example, the first layer (20) may be an organic layer formed of a composition including at least one of a dye and a pigment. The dye or pigment may have a color that does not affect the color of the polarizer or the image quality, and may be used with a maximum absorption wavelength of 400 nm to 700 nm. Through this, the first layer (20) may have the above-described group transmittance, thereby reaching the group transmittance of the first region.

In another specific example, the first layer (20) may be an inorganic layer formed by depositing or coating a material such as carbon black, or an organic layer formed by depositing or coating a material including an organic black dye or organic black pigment.

Below, the manufacturing method of the polarizer is described.

A polarizer can be manufactured by a method including the steps of manufacturing a polyvinyl alcohol-based film, in which at least one dichroic material, such as iodine or a dichroic dye, is dyed and stretched, performing a predetermined treatment on a portion of the polyvinyl alcohol-based film to form a first polarizer region, and forming a first layer on an upper surface and/or a lower surface of the first polarizer region. A region of the polyvinyl alcohol-based film that is not subjected to the treatment becomes a second polarizer region.

First, a step for manufacturing a polyvinyl alcohol-based film dyed with at least one dichroic substance, such as iodine or a dichroic dye, and stretched is described.

The dyed and stretched polyvinyl alcohol film can be manufactured by a process of dyeing and stretching a polyvinyl alcohol film. The order of dyeing and stretching in the method for manufacturing a polarizer is not limited. That is, the polyvinyl alcohol film can be dyed and then stretched, or it can be dyed and then stretched, or the dyeing and stretching can be performed simultaneously.

The polyvinyl alcohol-based film may be a conventional polyvinyl alcohol-based film used in the conventional manufacture of polarizers. Specifically, a film formed of polyvinyl alcohol or a derivative thereof may be used. The degree of polymerization of the polyvinyl alcohol or a derivative thereof may be 1000 to 5000, and the degree of saponification may be 80 mol% to 100 mol%. The thickness of the polyvinyl alcohol-based film may be 1 ㎛ to 30 ㎛, specifically 3 ㎛ to 30 ㎛, and within the above range, the film may be used in the manufacture of a thin polarizer.

The polyvinyl alcohol film can be washed and swollen before being dyed or stretched. By washing the polyvinyl alcohol film, foreign substances on the surface of the polyvinyl alcohol film can be removed. By swelling the polyvinyl alcohol film, the dyeing or stretching of the polyvinyl alcohol film can be improved. The swelling treatment can be performed by leaving the polyvinyl alcohol film in an aqueous solution of a swelling tank, as known to those skilled in the art. The temperature of the swelling tank and the swelling treatment time are not particularly limited. The swelling tank can further contain boric acid, an inorganic acid, a surfactant, etc., and the contents thereof can be adjusted.

A polyvinyl alcohol-based film can be dyed by dyeing the polyvinyl alcohol-based film in a dyeing bath containing at least one of iodine and a dichroic dye. In the dyeing process, the polyvinyl alcohol-based film is immersed in a dyeing solution, and the dyeing solution can be an aqueous solution containing iodine and a dichroic dye. Specifically, iodine is provided from an iodine-based dye, and the iodine-based dye can include at least one of potassium iodide, hydrogen iodide, lithium iodide, sodium iodide, zinc iodide, lithium iodide, aluminum iodide, lead iodide, and copper iodide. The dyeing solution can be an aqueous solution containing 1 wt% to 5 wt% of iodine and at least one of a dichroic dye. In the above range, the film can have a predetermined range of polarization and can be used in a display device.

The temperature of the dyeing tank can be 20°C to 45°C, and the immersion time of the polyvinyl alcohol-based film in the dyeing tank can be 10 seconds to 300 seconds. In the above range, a polarizer with high polarization degree can be realized.

By stretching a polyvinyl alcohol-based film in a stretching tank, the polyvinyl alcohol-based film can have polarization by orienting at least one of iodine and a dichroic dye. Specifically, stretching can be performed by both dry stretching and wet stretching. Dry stretching can be performed by interroll stretching, compression stretching, and heated roll stretching, and wet stretching can be performed in a wet stretching tank containing water at 35°C to 65°C. The wet stretching tank can further include boric acid to enhance the stretching effect.

The polyvinyl alcohol-based film can be stretched at a predetermined stretching ratio, and specifically, can be stretched so that the total stretching ratio becomes 5 to 7 times, specifically 5.5 to 6.5 times, and can prevent the phenomenon of cutting, wrinkles, etc. of the polyvinyl alcohol-based film stretched in the above range, and can implement a polarizer with high polarization degree and transmittance. Stretching can be performed as a single-stage stretching by uniaxial stretching, but by performing multi-stage stretching such as two-stage or three-stage stretching, it is also possible to prevent breakage while manufacturing a thin polarizer.

The above description describes the process of dyeing and then stretching a polyvinyl alcohol film, but dyeing and stretching may also be performed in the same reaction tank.

Before stretching the dyed polyvinyl alcohol film or after dyeing, the stretched polyvinyl alcohol film may be crosslinked in a crosslinking bath. Crosslinking is a process for dyeing the polyvinyl alcohol film with iodine or at least one dichroic dye more strongly, and boric acid can be used as a crosslinking agent. To enhance the crosslinking effect, a phosphoric acid compound, potassium iodide, etc. may be further included.

The dyed and stretched polyvinyl alcohol-based film may also be color-treated in a complementary color bath. The complementary color treatment is to immerse the dyed and stretched polyvinyl alcohol-based film in a complementary color bath containing a complementary solution containing potassium iodide. Through this, the color value of the polarizer can be lowered and the iodine anion I ^- inside the polarizer can be removed, thereby improving durability. The temperature of the complementary color bath can be 20°C to 45°C, and the complementary color bath immersion time of the polyvinyl alcohol-based film can be 10 seconds to 300 seconds.

Next, the above treatment can be applied to a portion of the polyvinyl alcohol-based film to form a first polarizing region.

A region irradiated with at least one of pulsed light from a Xenon Flash Lamp and a femtosecond laser to a portion of the above polyvinyl alcohol-based film can become a first polarizer region. In the present invention, the first polarizer region is formed by the above-described method to form the first layer.

A xenon flash lamp irradiates light in the form of pulses at a continuous wavelength of 200 nm to 800 nm, thereby reducing damage to a polyvinyl alcohol-based film dyed with at least one iodine or dichroic dye in a depolarized region when forming a region with a lower degree of polarization than before irradiation, compared to a conventional femtosecond or picosecond laser.

When irradiating pulsed light by a Xenon Flash Lamp, the detailed irradiation conditions may be an energy power of 300 V to 500 V, a pulse cycle of 0.5 Hz to 2 Hz, an irradiation time of 5 ms (milliseconds) to 15 ms, and an irradiation number of times of 1 to 10. In the above range, it can be helpful to obtain the first polarizer region of the present invention. When irradiating the light source, by closely contacting a mask of a desired shape on a dyed and stretched polyvinyl alcohol-based film, a portion where polarization depolarization is unnecessary can be controlled to maintain the light transmittance.

Femtosecond lasers can be irradiated at a beam size of 10 μm to 30 μm, a pulse frequency of 200 kHz to 400 kHz, and an energy density per pulse of 0.1 to 0.5 J/cm ² /Puls.

In one specific embodiment, the femtosecond laser includes at least two femtosecond lasers each selected from a wavelength range of 340 nm to 346 nm and a wavelength range of 510 nm to 520 nm.

Light in the wavelength range of 510 nm to 520 nm can decompose iodine and dichroic dyes attached to a polarizer by transitioning them from the ground state to the excited state, thereby eliminating the polarization function in the region irradiated with the light. When at least two femtosecond lasers selected respectively in the wavelength ranges of 340 nm to 346 nm and 510 nm to 520 nm are irradiated on a polarizer, the polarization function described above can be eliminated and the light transmittance can be increased, while the high temperature and high humidity reliability of the polarizer or polarizing plate can be improved.

Specifically, in a wavelength range of 340 nm to 346 nm, a femtosecond laser having a wavelength of 340 nm, 341 nm, 342 nm, 343 nm, 344 nm, 345 nm, 346 nm, preferably 343 nm, can be selected. Specifically, in a wavelength range of 510 nm to 520 nm, a femtosecond laser having a wavelength of 510 nm, 511 nm, 512 nm, 513 nm, 514 nm, 515 nm, 516 nm, 517 nm, 518 nm, 519 nm, 520 nm, preferably 515 nm, can be selected. Optimally, a femtosecond laser can be irradiated at each of the wavelengths of 343 nm and 515 nm.

In one specific embodiment, the first polarizer region can be formed by pulsed light irradiation alone by a Xenon Flash Lamp or by femtosecond laser irradiation alone.

In another specific embodiment, the first polarizer region can be formed by a combination of pulsed light irradiation by a Xenon Flash Lamp and femtosecond laser irradiation. For example, the first polarizer region can be formed by irradiating pulsed light by a Xenon Flash Lamp and irradiating femtosecond laser, irradiating femtosecond laser and irradiating pulsed light by a Xenon Flash Lamp, or irradiating pulsed light by a Xenon Flash Lamp and femtosecond laser simultaneously. Preferably, the femtosecond laser is irradiated after irradiating pulsed light by a Xenon Flash Lamp. However, the femtosecond laser should be irradiated under the minimum irradiation conditions that do not affect the first polarizer region of the present invention.

The method for manufacturing a polarizer of the present invention may additionally include at least one of heat treatment and water washing treatment of the irradiated region after pulsed light irradiation by a Xenon Flash Lamp or a combination of pulsed light irradiation by a Xenon Flash Lamp and laser irradiation. The treatment may help increase the reliability of the first polarizer region by preventing the polarization degree of the first polarizer region from returning to the state before forming the first polarizer region when the first polarizer region is left at high temperature and/or high temperature and high humidity for a long period of time.

The heat treatment may include treating the polarizer having the first polarizer region formed therein at 70° C. to 90° C. for 1 minute to 10 minutes. In this range, the reliability of the first polarizer region can be increased while minimizing the influence on regions other than the first polarizer region.

The washing treatment may include a treatment in which the polarizer having the first polarizer region formed is contacted with water at 30° C. to 60° C. for 1 to 10 minutes. The contacting treatment may be performed according to a conventional method known to those skilled in the art, such as a treatment in which the polarizer having the first polarizer region formed is immersed in the water or a treatment in which the polarizer is washed with the water.

Next, a polarizer can be manufactured by forming a first layer on the upper surface and/or lower surface of the first polarizer region.

The first layer can be formed by depositing or coating a composition including at least one of a dye and a pigment, an inorganic black dye including an organic black dye, carbon black, etc., on the upper surface and/or the lower surface of the first polarizer region. The deposition and coating methods can be performed by conventional methods known to those skilled in the art.

The polarizer (10) may have a thickness of 3 ㎛ to 50 ㎛, specifically 3 ㎛ to 30 ㎛. In the above range, it may be used in a polarizing plate.

Referring to Fig. 3, a polarizing plate according to one embodiment of the present invention will be described. Fig. 3 is a cross-sectional view of a polarizing plate according to one embodiment of the present invention.

Referring to FIG. 3, a polarizing plate (100) may include a polarizer (10), a first protective layer (30) laminated on an upper surface of the polarizer (10), and a second protective layer (40) laminated on a lower surface of the polarizer (10). The polarizing plate has a first region (110) and a second region (120), and the first region (110) includes a first layer (20).

Although not shown in Fig. 3, the upper surface of the polarizer (10) may be the observer side, and the lower surface of the polarizer (10) may be the display panel side of the optical display device. Accordingly, the upper surface of the polarizer (10) may be the light-emitting surface of the polarizer, and the lower surface of the polarizer (10) may be the light-incident surface of the polarizer.

The polarizer (10) and the first layer (20) are substantially the same as described above. An adhesive layer (50) is formed between the polarizer (10) and the first layer (20) and the first protective layer (30), so that the first protective layer (30) can be adhered to the polarizer (10). The adhesive layer (50) can be formed using a typical water-based adhesive or photocurable adhesive known to those skilled in the art. The adhesive layer (50) has a thickness greater than that of the first layer (20), and can have a thickness of 0.1 ㎛ to 10 ㎛, specifically, 0.1 ㎛ to 5 ㎛. In the above range, it can be used in a polarizing plate.

The first protective layer (30) can be laminated on the upper surface of the polarizer (10) to perform the function of protecting the polarizer.

The first protective layer (30) may be a photocurable coating layer or a protective film. The photocurable coating layer may include a cured layer formed of a composition including a photocurable compound or a liquid crystal layer formed of a liquid crystal polymer. The protective film may be a protective film commonly used as a protective film for a polarizer. For example, the protective film may include a protective film made of one or more resins from among cellulose-based films including triacetyl cellulose, polyester-based films including polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate, cyclic polyolefin-based films, polycarbonate-based films, polyether sulfone-based films, polysulfone-based films, polyamide-based films, polyimide-based films, polyolefin-based films, polyarylate-based films, polyvinyl alcohol-based films, polyvinyl chloride-based films, and polyvinylidene chloride-based films.

The first protective layer (30) may have a thickness of 1 µm to 100 µm, for example, 1 µm to 50 µm.

The second protective layer (40) can be laminated on the lower surface of the polarizer to perform the function of protecting the polarizer. The second protective layer (40) can provide an anti-reflection function to the polarizing plate by having a phase difference of a predetermined range.

The second protective layer may be a single-layer phase-shift layer or a laminate in which multiple phase-shift layers are laminated.

In one specific example, the second protective layer may include a first phase difference layer. The first phase difference layer can prevent reflection of external light by circularly polarizing linearly polarized light emitted after passing through a polarizer, thereby improving screen quality.

The first phase difference layer may have an in-plane phase difference (Re) of 100 nm to 220 nm, specifically 100 nm to 180 nm, for example, a λ/4 phase difference, at a wavelength of 550 nm. In this range, the reflectivity for external light can be lowered, thereby obtaining an effect of improving screen quality.

In another specific embodiment, the second protective layer may include the first phase difference layer and the second phase difference layer.

The second phase difference layer may have an in-plane phase difference (Re) of 225 nm to 350 nm, specifically 225 nm to 300 nm, for example, a phase difference of λ/2, at a wavelength of 550 nm. In this range, the reflectivity for external light can be lowered, thereby obtaining an effect of improving screen quality.

In this specification, the 'in-plane phase difference (Re)' can be calculated as Re = (nx - ny) x d (where nx and ny are the refractive indices in the slow axis direction and the fast axis direction of the phase difference layer, respectively, and d is the thickness of the phase difference layer (unit: nm)).

The first phase difference layer and the second phase difference layer can each be a photocurable coating layer or protective film described in the first protective layer.

The second protective layer (40) may have a thickness of 1 µm to 100 µm, for example, 1 µm to 50 µm.

Hereinafter, an optical display device according to one embodiment of the present invention will be described.

The optical display device of the present invention includes the polarizing plate of the present invention. The optical display device may include an organic light-emitting display device, a liquid crystal display device, preferably an organic light-emitting display device, etc.

Referring to FIG. 4, the optical display device of the present invention will be described in more detail.

Referring to FIG. 4, the optical display device may include a display panel (200), a polarizing plate (100) positioned on the upper side of the display panel (200), and an image sensor (300) positioned on the lower side of the display panel (200).

The display panel (200) can have a substrate layer and a plurality of light-emitting elements formed thereon. The display panel (200) is not perforated for insertion of an image sensor (300).

The polarizing plate (100) includes a first region (110) and a second region (120), and includes the polarizing plate of the present invention. Both the first region (110) and the second region (120) form an image display region of the optical display device. The polarizing plate (100) is not perforated for insertion of the image sensor (300).

The first region (110) has light-emitting elements formed less densely than the second region (120). Through this, the image display function by the image sensor (300) can be implemented while the image display function by the display panel (200) can be performed at the same time.

The image sensor (300) is positioned at the bottom of the first region (110). The image sensor (300) may include a camera, etc., but is not limited thereto.

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, these are presented as preferred examples of the present invention and cannot be interpreted as limiting the present invention in any way.

The specific specifications of the components used in the following examples and comparative examples are as follows.

(1) Polarizer material: Polyvinyl alcohol film (VF-PE3000, Kuraray, Japan, thickness: 30㎛)

(2) Protective film: Triacetyl cellulose film (KC4UYW, Konica, Japan, thickness 40㎛)

Example 1

A polyvinyl alcohol film washed with water was subjected to swelling treatment in a swelling tank containing water at 30°C.

The polyvinyl alcohol-based film passed through the swelling tank was treated in a dyeing tank at 30°C containing an aqueous solution containing 3 wt% of potassium iodide for 30 to 200 seconds. The polyvinyl alcohol-based film passed through the dyeing tank was passed through a wet crosslinking tank containing an aqueous solution containing 3 wt% of boric acid at 30 to 60°C. The polyvinyl alcohol-based film passed through the crosslinking tank was stretched in an aqueous solution containing 3 wt% of boric acid at 50 to 60°C, but the stretching was performed so that the total stretching ratio was 6 times, thereby producing a dyed and stretched polyvinyl alcohol-based film.

Using a Xenon Flash Lamp, pulse light of a wavelength of 200 nm to 800 nm by a Xenon Flash Lamp was irradiated once to only a portion of the polyvinyl alcohol-based film under the conditions of Table 1 below. The area irradiated with the pulse light by the Xenon Flash Lamp becomes the first polarizer area among polarizers, and the area not irradiated with the pulse light by the Xenon Flash Lamp becomes the second polarizer area among polarizers.

A polarizer was manufactured by forming a first layer by depositing or coating a material including an organic black dye such as carbon black or an organic black pigment on the upper surface of the first polarizer region. The first layer was formed in contact with the first polarizer region.

A polarizing plate was manufactured by bonding a protective film to each side of the polarizer using an adhesive (Z-200, Nippon Goshei Co., Ltd.). The portion of the polarizing plate where the first layer was formed became the first region, and the portion of the polarizing plate where the first layer was not formed became the second region.

Examples 2 to 3

A polarizing plate having a first region and a second region formed therein was manufactured by the same method as in Example 1, except that the irradiation conditions of pulsed light by a xenon flash lamp in Example 1 were changed to the conditions in Table 1 below or the method of forming the first layer was changed.

Example 4

A polarizing plate was manufactured in the same manner as in Example 1, except that pulsed light was irradiated by a Xenon Flash Lamp and the plate was immersed in lukewarm water at 50°C for 3 minutes.

Comparative Example 1

In Example 1, a polarizing plate was manufactured in the same manner as in Example 1, except that the first layer was not formed in the first polarizing region.

The following physical properties were evaluated for the polarizing plates manufactured in the examples and comparative examples, and the results are shown in Table 1 below.

(1) Polarization degree of the first region and the second region: The polarization degree of the first region and the second region of the polarizing plates manufactured in the examples and comparative examples was measured at a wavelength of 200 nm to 800 nm using a UV-Visible Spectrophotometer V730 (JASCO).

(2) Group transmittance (unit: %) of the first region, the second region, the first polarizer region, and the second polarizer region among the polarizing plates manufactured in the examples and comparative examples was measured for group transmittance at wavelengths of 200 nm to 800 nm for each of the first region and the second region using a UV-Visible Spectrophotometer V730 (JASCO).

A polarizer was manufactured in substantially the same manner as in the examples and comparative examples, and group transmittance was measured for the first polarizer region and the second polarizer region among the polarizers in the same manner as above.

(3) Uniformity of color of a photo or video according to the camera shooting direction: The polarizing plates manufactured in the examples and comparative examples were mounted on the display panel as the viewing-side polarizing plates. When the long-axis direction of the display was 90° and the short-axis direction was 0°, the sunglasses effect was evaluated before and after the long-axis direction of the display panel was rotated 90°. The sunglasses effect refers to the quality difference according to the angle of the camera. If there was no color difference in the image before and after 90° rotation, it was evaluated as ○, and if color distortion occurred, it was evaluated as X.

(4) Difference in screen quality between the first area where the image sensor is placed and the second area where the image sensor is not placed: The polarizing plates manufactured in the examples and comparative examples were mounted on the display panel as the viewing-side polarizing plates. The brightness, pixel resolution, color, etc. of the images in each of the first area and the second area were compared by examining the images under a microscope. If the difference between areas was small, it was evaluated as ○, if it was somewhat visible, it was evaluated as △, and if the difference was clearly visible, it was evaluated as X.

(5) Reliability: The polarizing plates manufactured in the examples and comparative examples were left at 60℃ and 95% relative humidity for 500 hours. Then, the light transmittance of the first region was measured before and after leaving using a UV-Visible Spectrophotometer V730 (JASCO) to evaluate the degree of change. If the change range was 5% or less, it was evaluated as ○, if it was more than 5% but less than or equal to 30%, it was evaluated as △, if it was more than 30% but less than or equal to 60%, it was evaluated as △△, and if it was more than 60%, it was evaluated as X.

Example Comparative example 1 2 3 4 1 Energy Power (V) 500 300 300 500 500 Survey time (ms) 15 15 5 15 15 Including the first floor include include include include Not included Polarization Area 1 5% 10% 15% 2% 5% Area 2 99% 99% 99% 99% 99% Group penetration rate Area 1 43% 43% 43% 43% 99% Area 2 43% 43% 43% 43% 43% Group penetration rate First polarizer region 90% 85% 80% 90% 90% Second polarizer region 44% 44% 44% 44% 44% Color uniformity according to shooting direction ○ ○ ○ ○ X Difference in screen quality ○ △ △ ○ X reliability △ △ △ ○ X

As shown in Table 1 above, the polarizing plate of the present invention can make the color or clarity of a photograph or video substantially the same regardless of the shooting direction, and can make the color or clarity of the screen substantially the same depending on the viewing direction when viewed with polarizing sunglasses, and minimize the difference in screen quality between the first area where the image sensor is placed and the second area where the image sensor is not placed, and has excellent reliability.

On the other hand, the polarizing plate of the comparative example that did not have the first layer could not obtain the effect of the present invention.

Simple modifications or changes of the present invention can be easily implemented by those skilled in the art, and all such modifications or changes can be considered to be included in the scope of the present invention.

Claims (13)

A polarizing plate having a first region and a second region included within an image display area,
The above first region has a polarization degree of more than 0% and less than or equal to 30% and a group transmittance of 20% to 90%,
The difference in group transmittance between the first area and the second area is 10% or less,
The above polarizing plate further comprises a first layer,
A polarizing plate, wherein the first layer is formed only in the first region.
A polarizing plate in claim 1, wherein the second region has a polarization degree of 80% or more.
A polarizing plate in the first aspect, wherein the polarizing plate includes a first polarizing region corresponding to the first region, a second polarizing region corresponding to the second region, and a polarizer including the first layer.
A polarizing plate in claim 3, wherein the first layer is laminated on at least one surface of the first polarizing region.
A polarizing plate according to claim 3, wherein the first polarizing region includes a polyvinyl alcohol-based film.
A polarizing plate in claim 5, wherein the first layer has a lower group transmittance compared to the first polarizing region.
A polarizing plate in claim 5, wherein the first polarizing region and the laminate of the first layer have a polarization degree of more than 0% and less than or equal to 30% and a group transmittance of 20% to 90%.
A polarizing plate in claim 5, wherein the thickness of the first layer is 1% to 20% of the thickness of the first polarizing region.
A polarizing plate in claim 1, wherein the first layer includes an organic layer, an inorganic layer, or an organic-inorganic mixed layer.
A polarizing plate in claim 1, wherein the first layer contains at least one of a dye and a pigment.
A polarizing plate in accordance with claim 3, wherein a protective layer is further formed on at least one surface of the polarizer.
An optical display device comprising a polarizing plate according to any one of claims 1 to 11.
In claim 12, the optical display device includes a display panel, the polarizing plate formed on an upper portion of the display panel, and an image sensor formed on a lower portion of the display panel, wherein the image sensor is disposed on a lower portion of the first region of the polarizing plate.