KR20190125607A - Optical filter and autostereoscopic display comprising same - Google Patents

Abstract

According to the present invention, an optical filter increases invisibility by correcting the difference in reflected light between an etched portion and a non-etched portion of a pattern of an electrode layer due to an interference effect of one or more composite refractive layers, so a viewer cannot recognize a moire pattern. Accordingly, the optical filter may be used in an autostereoscopic display device for viewing a stereoscopic image without glasses or for viewing a 2D image without degradation of resolution.

Description

Optical filter and autostereoscopic 3D display device including the same {OPTICAL FILTER AND AUTOSTEREOSCOPIC DISPLAY COMPRISING SAME}

The present invention relates to a filter used in an autostereoscopic 3D display device capable of switching 2D / 3D without glasses, and more particularly, a filter having excellent surface hardness while preventing moire phenomenon, and an autostereoscopic 3D display device including the same. It is about.

As the demand for 3D stereoscopic images has increased over the years, various technologies for devices for displaying 3D stereoscopic images have been developed. In the 3D stereoscopic image, different planar images are input to both eyes of the viewer, and the viewer feels the stereoscopic feeling by fusion and recognition.

Until now, the image separation method through glasses has occupied most of the 3D image display device, but recently, the autostereoscopic 3D image technology has been rapidly developed around the parallax barrier and lenticular lens method. have. Parallax Barrier is easy to switch screen between 2D / 3D and can adjust viewing distance, but it is a big problem that brightness decreases due to limitation of view point and high resolution, which is advantageous in terms of brightness and viewing angle in large display field. The trend is to shift the focus. In particular, as the high resolution of the display has recently emerged as an important issue, technology development for the liquid crystal lens method capable of 2D / 3D conversion, which has improved the resolution degradation of the conventional lenticular lens method, is being actively conducted.

For example, Korean Patent Laid-Open No. 2012-0074190 discloses a liquid crystal GRIN (gradient index) lens type of Fresnel lens type. As shown in FIGS. 3A and 3B, the liquid crystal GRIN lens system can provide both 2D and autostereoscopic images without degrading the resolution by changing the refractive index of the liquid crystal depending on whether voltage is applied.

Republic of Korea Patent Publication No. 2012-0074190

In order to compensate for the reduced resolution in implementing autostereoscopic images, a method of aligning and bonding at a specific slanted angle between pixels of a display device and a lens pattern is known. 4 is a schematic diagram illustrating that the electrode pattern 135 of the optical filter 100 is bonded to the image pixels 210 of the display panel 200 at a specific angle Θ. However, when the display pixel and the lens pattern are bonded at a specific angle in this manner, there is a problem that an irregular third shape called moire is expressed.

Therefore, the present invention, in order to solve the above problems, by attaching a separate composite refractive layer to the electrode layer for the lens pattern to reduce the visibility of the electrode pattern to prevent the moire phenomenon, along with the improved durability in the process And to provide an autostereoscopic 3D display device including the same.

According to the above object, the present invention is a first electrode layer; A second electrode layer disposed in parallel and patterned to face the first electrode layer; A liquid crystal layer disposed between the first electrode layer and the second electrode layer and containing a liquid crystal; And at least one composite refractive layer disposed between the liquid crystal layer and the second electrode layer and having a refractive index different from that of the second electrode layer.

In addition, the present invention provides an autostereoscopic 3D display device including the optical filter and a plurality of image pixels disposed on one surface of the optical filter.

The optical filter according to the present invention improves invisibility by correcting the difference in the reflected light between the etched portion and the non-etched portion of the electrode layer by the interference effect of one or more composite refractive layers, thereby preventing viewers from recognizing the moire pattern. have. In addition, since there is no limitation to limit the moire pattern to the angle at which the moire pattern is not viewed, design freedom may be increased. In addition, by applying a hard coating material having a high mechanical strength to the composite refractive layer it can improve the handleability by protecting the electrode in the manufacturing process of the optical filter.

Accordingly, the optical filter may be used in an autostereoscopic 3D display device for viewing a 3D stereoscopic image without glasses or for viewing a 2D image without degrading the resolution.

1 is a cross-sectional view of an optical filter and an autostereoscopic 3D display device including the same according to an example of the present invention.
2A and 2B illustrate an operation process of an autostereoscopic 3D display device using an optical filter.
3A and 3B show a change in liquid crystal depending on whether a voltage is applied.
4 illustrates that the electrode pattern and the image pixels are bonded at a specific angle.

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

1 is a cross-sectional view of an optical filter and an autostereoscopic 3D display device including the same according to an exemplary embodiment of the present invention.

Optical filter 100 according to the present invention includes a first electrode layer 120; A second electrode layer 130 disposed in parallel with the first electrode layer 120 and patterned; A liquid crystal layer 140 disposed between the first electrode layer 120 and the second electrode layer 130 and containing liquid crystal; And at least one composite refractive layer 150 disposed between the liquid crystal layer 140 and the second electrode layer 130 and having a refractive index different from that of the second electrode layer 130.

The optical filter may be a GRIN (gradient index) lens filter that arranges liquid crystals to have the same refractive index as that of the lens according to an electric field distribution using an electrode pattern structure.

The lenticular lens method using the liquid crystal has good luminance and can provide both 2D and autostereoscopic images without degrading the resolution depending on whether voltage is applied.

2A and 2B illustrate an operation process of an autostereoscopic 3D display device using an optical filter. That is, the image emitted from the pixels divided by viewpoints may go straight according to whether the voltage is applied to the liquid crystal layer to express a 2D plane image without degrading the resolution (see FIG. 2A), or may be refracted to project a stereoscopic image in both eyes. (See FIG. 2A).

The optical filter may further include a spacer layer disposed between the first electrode layer and the liquid crystal layer and having a shape in which lenticular lenses are concave toward the liquid crystal layer.

In addition, the optical filter may further include a first base layer and a second base layer disposed on the outer periphery of the first electrode layer and the second electrode layer.

Hereinafter, each component will be described in more detail.

The first electrode layer and the second electrode layer serve to change the alignment of the liquid crystal by applying a voltage to the liquid crystal layer.

The first electrode layer and the second electrode layer may be made of a transparent conductive material.

Materials of the first electrode layer and the second electrode layer include indium tin oxide (ITO), carbon nanotubes (CNT), metal meshes, silver nanowires, and the like. Can be mentioned.

The second electrode layer is a patterned electrode layer, and specifically, may be an electrode layer patterned to have a non-etching portion 131 and an etching portion 132.

The first electrode layer and the second electrode layer may be formed on inner surfaces of the first base layer and the second base layer disposed in parallel with each other.

The first substrate layer and the second substrate layer may be a transparent plastic or a glass substrate, and more specifically, may be a transparent plastic.

Specific examples of the material of the first and second substrate layers include polyether sulfone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate (polyethylene naphthalate). , PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyallylate, polyimide, polycarbonate, PC, cellulose triacetate cellulose, TAC), cellulose acetate propionate (CAP) and mixtures thereof.

Preferably, the first substrate layer and the second substrate layer may use polyethylene terephthalate, polycarbonate, cellulose triacetate or polyacrylate having optically isotropic properties.

In addition, the first base material layer and the second base material layer have excellent adhesion to the polymer resin included in the spacer layer, transmittance of light incident from the rear surface is 90% or more, and the smoothness of the surface is uniform, resulting in variations in luminance. Not good to bring.

The thickness of the first base layer and the second base layer may be 50 ~ 500 ㎛, 50 ~ 200 ㎛, or 80 ~ 125 ㎛.

The spacer layer serves as a spacer disposed between the first electrode layer and the second electrode layer to form a liquid crystal space.

The spacer layer has a pattern in which concave lenticular lenses are arranged on a bottom surface thereof. The refractive index of the spacer layer may match any one of the abnormal light refractive index ne and the normal light refractive index no of the liquid crystal.

The height of the lenticular lens may be 2 to 300 μm, 5 to 120 μm, or 20 to 80 μm, and thus the height of the spacer layer may also be 2 to 300 μm, 5 to 120 μm, or 20 to 80 μm.

The size of the lenticular lens may be a size commonly used according to the resolution and pixel size of the display element or the viewing distance, and may have a radius of about 0.01 to 10 mm, 0.05 to 8 mm, and 0.1 to 5 mm, for example. .

For example, a polymer resin may be applied onto a substrate, molded using a tool having a predetermined pattern, and then cured to form a lenticular lens having a concave shape.

The polymer resin used in the spacer layer may be a thermosetting resin or a UV curable resin that is commonly used, for example, acrylic, urethane, epoxy, vinyl, polyester, polyamide resin or mixtures thereof. Can be used. Specifically, the polymer resin may be a (meth) acrylate resin, unsaturated polyester resin, polyester (meth) acrylate resin, silicone urethane (meth) acrylate resin, silicone polyester (meth) acrylate resin, fluorine urethane ( Meth) acrylate resins and mixtures thereof.

More specifically, the binder resin may be an acrylic resin that can implement excellent coating properties, mechanical properties, adhesion, durability, and the like. The acrylic resin is a repeating unit of methyl methacryl, methacryl, ethyl acryl, butyl acryl, aryl acryl, hexyl acryl, isopropyl methacryl, benzyl acryl, vinyl acryl, 2-methoxyethyl acryl or styrene, for example. It may be a homopolymer or a copolymer obtained by copolymerizing two or more kinds of the above components.

The liquid crystal of the liquid crystal layer causes a change in refractive index according to the application of a voltage between the first electrode layer and the second electrode layer.

Specifically, the refractive index of the liquid crystal layer may vary according to the alignment state of the liquid crystal.

More specifically, the liquid crystal is oriented in a predetermined direction as the voltage is applied and the refractive index of the liquid crystal layer is changed so that the film for the autostereoscopic 3D display device of the present invention can be converted into 2D mode and 3D mode.

For example, the liquid crystal of the liquid crystal layer is injected into the concave space of the spacer layer to change the refractive index according to the application of voltage.

Accordingly, the liquid crystal may have the same or different refractive index as that of the spacer layer depending on whether current is applied.

For example, when the film for an autostereoscopic 3D display device of the present invention operates in the 2D mode, the spacer layer refractive index is equal to the abnormal light refractive index (ne) or the normal light refractive index (no) of the liquid crystal layer. Allow the incident light to pass through without refracting.

On the other hand, when the film for an autostereoscopic 3D display device of the present invention operates in the 3D mode, by changing the alignment state of the liquid crystal to change the refractive index of the liquid crystal layer, the light incident from the display panel is refracted in the liquid crystal layer and stereoscopic The image will be implemented.

The composite refractive layer has an interference effect due to a different refractive index than that of the second electrode layer, thereby improving the non-visibility by correcting the difference in the reflected light between the etching portion and the non-etching portion of the electrode layer, thereby preventing the viewer from recognizing the moire pattern. Can be.

The composite refractive layer may have the same refractive index as the second electrode layer or lower than the second electrode layer with respect to a wavelength of 550 nm.

The composite refractive layer may be composed of two or more layers, or three or more layers.

For example, the composite refractive layer may include a first composite refractive layer, a second composite refractive layer, and a third composite refractive layer having different refractive indices.

In this case, the first composite refractive layer, the second composite refractive layer, and the third composite refractive layer may be stacked on the second electrode layer.

As a specific example, the refractive index for the 550 nm wavelength of the second composite refractive layer is higher than that of the first and third composite refractive layers and lower than that of the second electrode layer. Specifically, the second composite refractive layer may have a refractive index greater than 0.01 to 0.25 for the 550 nm wavelength than the first composite refractive layer and the third composite refractive layer.

In addition, the refractive index of the first composite refraction layer and the third composite refraction layer with respect to the wavelength of 550 nm may be the same as or lower than the second base layer. In detail, the first composite refractive layer and the third composite refractive layer may have the same refractive index with respect to the second substrate layer and the wavelength of 550 nm, or may be as low as 0.01 to 0.2.

In addition, the refractive indexes for the 550 nm wavelengths of the first composite refractive layer and the third composite refractive layer may be similar to or the same, for example, a difference in refractive index thereof may be 0.20 or less.

The first composite refractive layer is stacked on the second substrate layer, and serves to enhance the adhesion between the second substrate layer and the second composite refractive layer as well as causing thin film interference.

The refractive index for the 550 nm wavelength of the first composite refractive layer is lower than that of the second composite refractive layer, and may be similar to or higher than that of the third composite refractive layer. Can be lower or similar to the second substrate layer It is preferable.

For example, the refractive index for the 550 nm wavelength of the first composite refractive layer may be 1.5 to 1.66, more specifically, 1.52 to 1.66, and more specifically, 1.56 to 1.66. When the refractive index is in the above range, the effect of thin film interference between the second substrate layer and the second composite refractive layer may be more excellent.

In addition, the thickness of the first composite refractive layer may be 5 ~ 500 nm, if more limited may be 10 ~ 320 nm, if most limited may be 20 ~ 100 nm. When the thickness is in the above range, the thin film interference effect is more excellent, and the adhesion with the second composite refractive layer can be more excellent.

Further, the resin that can be used as the main component of the first composite refractive layer includes a urethane acrylate resin, an epoxy acrylate resin, a polyester resin, and a mixed resin thereof.

In order to control the refractive index of the first composite refractive layer, ZrO ₂ , TiO ₂ , ZnO ₂ , Sb ₂ O ₃ , Sb ₂ O ₅ , antimony tin oxide (ATO), antimony zinc oxide (AZO), phosphorous tin oxide (PTO) ) And combinations thereof may be further added. The content of the added particles may be 30 to 100 parts by weight based on 100 parts by weight of the solid content of the raw material resin used in the first composite refractive layer.

In addition, a silicon-based leveling agent may be added to the first composite refractive layer, and the content of the silicon-based leveling agent may be 0.1 to 2.0 parts by weight based on 100 parts by weight of the solid content of the raw material resin used in the first composite refractive layer.

The second composite refractive layer is stacked on the first composite refractive layer, and has a higher refractive index than the first composite refractive layer and the third composite refractive layer to effectively induce thin film interference.

For example, the refractive index of the second composite refractive layer with respect to the 550 nm wavelength may be 1.67 to 1.75, more specifically, 1.68 to 1.74, and more specifically, 1.69 to 1.72. When the refractive index is in the above range, the effect of thin film interference between the first and third composite refractive layers may be more excellent.

In addition, the thickness of the second composite refractive layer is in the range of 1 to 500 nm, if more limited may be in the range 5 to 250 nm, if more limited may be in the range 15 to 100 nm. When the thickness is in the above range, since the appearance interference pattern hardly occurs, the refractive index of the second composite refractive layer can be adjusted widely. There is an advantage.

In addition, as the resin that can be used as the main component of the second composite refractive layer, a urethane acrylate resin, an epoxy acrylate resin, a melamine resin, and a mixed resin thereof may be used.

In addition, the second composite refractive layer has ZrO ₂ , TiO ₂ , ZnO ₂ , Sb ₂ O ₃ , Sb ₂ O ₅ , antimony tin oxide (ATO), antimony zinc oxide (AZO), and phosphorus tin (PTO) for controlling the refractive index. oxide) and combinations thereof may be further added. The content of the added particles may be 50 to 200 parts by weight based on 100 parts by weight of the solid content of the raw material resin used in the second composite refractive layer.

In addition, a silicon-based leveling agent may be added to the second composite refractive layer, and the content of the silicon-based leveling agent may be 0.1 to 2.0 parts by weight based on 100 parts by weight of the solid content of the raw material resin used in the second composite refractive layer.

The third composite refractive layer is stacked on the second composite refractive layer and has a role of contributing to crystallization of the second electrode layer as well as causing thin film interference. In the manufacture of the optical filter, a heat treatment process may be performed in the last step to crystallize the second electrode layer, during which the residual monomers, oligomers and the like from the second base layer, the first composite refractive layer and the second composite refractive layer are The microorganisms may migrate to the second electrode layer to lower the crystallization of the second electrode layer. However, such a transition may be blocked by the third composite refractive layer to contribute to the crystallization of the second electrode layer.

The refractive index for the 550 nm wavelength of the third composite refractive layer may be similar to or the same as the first composite refractive layer, and is lower than the refractive index of the second composite refractive layer.

For example, the refractive index for the 550 nm wavelength may be 1.3 to 1.6, more specifically, may be 1.40 to 1.55, and most limitedly, may be 1.43 to 1.55. When the refractive index is in the above range, the effect of thin film interference between the second composite refractive layer and the second electrode layer may be more excellent.

In addition, the thickness of the third composite refractive layer may be 1 to 50 nm, and may be 5 to 40 nm if more limited. When the thickness is in the above range, the effect of preventing the ITO crystallization inhibitory factors that migrate from the lower layer including the second composite refractive layer may be better.

In addition, as a raw material that can be used as a main component of the third composite refractive layer, silicon dioxide, silicon, aluminum oxide, magnesium fluoride (MgF ₂ ), and mixtures thereof may be used.

The optical filter according to the present invention is implemented in the lower display panel by correcting a difference in reflecting color and reflectance between the reflected light of the non-etched portion and the reflected light of the etched portion by the thin film interference effect of the one or more composite refractive layers. It may not deteriorate the desired image quality.

Preferably, the optical filter satisfies ΔR value represented by the following formula (1): 0 or more and 1.0 or less.

[Equation 1]

Wherein i is each wavelength in the visible region, r _1i is the reflectance of the non-etched portion of the second electrode layer at each wavelength, r _2i is the reflectance of the etched portion of the second electrode layer at each wavelength, and n is the measured wavelength The total number.

Preferably, the optical filter has a ΔER value represented by Equation 2 below when measuring a reflected color according to an L * a * b * color coordinate system with reflected light of 2 ° field of view to a D65 light source. More than 6.0 is satisfied.

[Equation 2]

Wherein L * ₁ , a * ₁ and b * ₁ are L *, a * and b * of the reflection color of the non-etched portion of the second electrode layer, respectively; L * ₂ , a * ₂ and b * ₂ are L *, a *, and b * of the reflection color of the etching part of a 2nd electrode layer, respectively.

When the ΔR and ΔER values are within the above ranges, the difference in reflectance in the visible region is minimized by correcting optical characteristics between the non-etched portion and the etched portion of the second electrode layer, and visual recognition of the non-etched portion and the etched portion of the second electrode layer is minimized. It can be difficult.

In accordance with another aspect of the present invention, a method of manufacturing an optical filter 100 includes: manufacturing a top plate by forming a first electrode layer 120 on a first base layer 110 with reference to FIG. 1; Manufacturing a lower plate by forming a patterned second electrode layer 130 having a non-etched portion 131 and an etched portion 132 on the second substrate layer 160; Forming at least one composite refractive layer (150) having a refractive index different from that of the second electrode layer (130) on the second electrode layer (130); Bonding the upper plate and the lower plate to each other; And forming a liquid crystal layer 140 by injecting a liquid crystal between the first electrode layer 120 and the second electrode layer 130.

Thereafter, a wire for applying an electric field may be connected to the first electrode layer and the second electrode layer.

The optical filter manufactured as described above corrects the difference in the reflected light between the non-etched portion and the etched portion of the pattern of the electrode layer by the interference effect of one or more composite refractive layers to increase the non-visibility, thereby preventing the viewer from recognizing the moire pattern. I can do it. In addition, since there is no limitation to limit the moire pattern to the angle at which the moire pattern is not viewed, design freedom may be increased. In addition, by applying a hard coating material having a high mechanical strength to the composite refractive layer it can improve the handleability by protecting the electrode in the manufacturing process of the optical filter.

Accordingly, the optical filter may be used in an autostereoscopic 3D display device for viewing a 3D stereoscopic image without glasses or for viewing a 2D image without degrading the resolution.

Such an autostereoscopic 3D display device, with reference to Figure 1, the optical filter 100; And a plurality of image pixels 200 disposed on one surface of the optical filter.

The present invention will be described in more detail with reference to the following Examples. However, the following examples are only for exemplifying the present invention, and the scope of the present invention is not limited to these examples.

Example 1

An indium tin oxide (ITO) layer having a refractive index of 1.7 and a thickness of 20 nm was formed on the transparent substrate layer, and a composite refractive layer having a refractive index of 1.46 and a thickness of 15 nm was formed thereon. The reflectance at 550 nm wavelength for the resulting multilayer sheet was measured at 0.2%.

As the reflectance is lowered, the degree of visual recognition of the corresponding area is lowered. Therefore, it was confirmed that it is possible to prevent the moire phenomenon.

Comparative Example 1

The same procedure as in Example 1 was repeated, but the multilayer sheet was obtained without forming the composite refractive layer. The reflectance at 550 nm wavelength for the resulting multilayer sheet was measured at 5.8%.

100: optical filter,
110: first substrate layer, 120: first electrode layer,
130: second electrode layer, 131: non-etching portion,
132: etching portion, 135: electrode pattern,
140: liquid crystal layer, 141: liquid crystal,
150: composite refractive layer, 160: second substrate layer,
200: display panel, 210: image pixel,
Θ: tilt angle.

Claims (5)

A first electrode layer;
A second electrode layer disposed in parallel and patterned to face the first electrode layer;
A liquid crystal layer disposed between the first electrode layer and the second electrode layer and containing a liquid crystal; And
And at least one composite refractive layer disposed between said liquid crystal layer and said second electrode layer and having a different refractive index than said second electrode layer.
The method of claim 1,
And the optical filter is a GRIN (gradient index) lens filter that arranges liquid crystals to have the same refractive index as the lens according to the electric field distribution using an electrode pattern structure.
The method of claim 1,
And the composite refractive layer has a refractive index equal to or lower than the second electrode layer for a 550 nm wavelength.
The method of claim 1,
And the composite refractive layer comprises a first composite refractive layer, a second composite refractive layer and a third composite refractive layer having different refractive indices.
Claim 1 optical filter; And
An autostereoscopic 3D display device comprising a plurality of image pixels disposed on one surface of the optical filter.

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