KR102577319B1 - Cover Dust Laminate and Head Up Display including the Cover Dust Laminate - Google Patents

Abstract

The present application can provide a cover dust laminate that does not cause so-called oxidation phenomenon even when driven or maintained under very harsh conditions (e.g., very high temperature conditions). In addition, the cover dust laminate is applied to the head-up display to prevent internal components such as the image generating device from burning, while realizing clear image quality, and when displaying two independent screens, the luminance ratio of each screen is appropriate. A head-up display can be provided.

Description

Cover dust laminate and head up display including the same {Cover Dust Laminate and Head Up Display including the Cover Dust Laminate}

This application relates to a cover dust laminate and a head-up display including the same.

A Head Up Display (HUD) is a device that visualizes driving information, such as vehicles, as a virtual image in front of the driver's field of view.

For example, as shown in FIG. 1, the head-up display 10 includes an image generating device 20 that generates an optical signal corresponding to an image, and a cover dust laminate to prevent deterioration of internal components due to external light, etc. 100), light control means (reflector 40 and/ or beam splitter, etc.).

The cover dust laminate 100 has played a role in preventing deterioration of internal components, for example, the image generating device 20, due to external light. However, the conventional cover dust laminate 100 includes an optical laminate to which a reflective polarizer is applied, so external light is reflected back to the outside and enters the driver's field of view, causing problems such as not being able to perceive a clear screen. there was.

In addition, head-up displays, especially when applied to vehicles, are often exposed to high-temperature environments and/or environments with large temperature changes in summer and winter, so the durability of the cover dust laminate has been a problem.

Accordingly, it is required to maintain durability even when the head-up display is maintained and/or driven under much harsher conditions than existing ones, for example, at very high temperatures, while maintaining clear image quality without noise caused by reflection of external light. .

The present application provides a cover dust laminate that has excellent high-temperature durability and enables clear image quality, and a head-up display including the same.

Among the physical properties mentioned in this specification, the physical properties where measurement temperature and/or measurement pressure affect the results are the results of measurements at room temperature and/or pressure, unless specifically stated otherwise.

The term room temperature refers to a natural temperature that is not heated or reduced, for example, any temperature in the range of 10°C to 30°C, about 23°C, or about 25°C. Additionally, in this specification, the unit of temperature is °C unless otherwise specified.

The term normal pressure is the natural pressure that is not pressurized or decompressed, and usually means about 1 atmosphere of atmospheric pressure.

In the case of a physical property in which the measured humidity affects the results in this specification, the physical property is a physical property measured at room temperature and/or normal pressure with natural humidity that is not specifically adjusted.

In this specification, the term lower direction refers to a direction from the protective substrate of the cover dust laminate toward the absorption-type polarizer, and the term upper direction refers to the opposite direction and refers to the direction from the absorption-type polarizer to the protection substrate.

This application relates to a cover dust laminate including an absorptive polarizer. The term cover dust laminate is located on the path of external light incident from the head-up display to the image generating device and on the path of the optical signal emitted from the image generating device, so that at least a portion of the external light is introduced into the image generating device. It refers to an optical laminate that exists to block and transmit the optical signal emitted from the image generating device. Additionally, in the present application, the term polarizer may refer to, for example, an element or film that exhibits a polarization function.

As long as the polarizer applied in this application is an absorption type polarizer, the specific type is not limited. In the above, the absorption-type polarizer may be, for example, an absorption-type linear polarizer. The term absorptive linear polarizer transmits linearly polarized light vibrating in one direction from incident light vibrating in various directions, and absorbs light vibrating in the other direction, for example, polarized light in a direction perpendicular to the transmitted linearly polarized light. It may refer to a device that has a function.

The most common absorption type linear polarizer known is the so-called poly(vinylalcohol) (hereinafter referred to as PVA) polarizer. In this specification, the term PVA refers to polyvinyl alcohol and/or its derivatives, unless otherwise specified. PVA polarizers include, for example, stretched PVA films in which anisotropic absorbent substances such as iodine or dichroic dyes are adsorbed and oriented, or so-called coated PVA polarizers, which are formed thinly by applying PVA through a coating method. It is known that, in this application, all of the above types of polarizers can be applied.

The polarizer applied in the examples of this application is a PVA polarizer, and this polarizer is usually manufactured by applying a dyeing and stretching process to a PVA raw film. In the above manufacturing process of the PVA polarizer, additional processes such as swelling, cross-linking, cleaning, and/or complementary color processes may be performed if necessary, and the process of manufacturing the PVA polarizer through these processes is known.

In one example, the thickness of the absorption-type polarizer may be in the range of 5 μm to 50 μm. In other examples, at least 6 μm, at least 7 μm, at least 8 μm, at least 9 μm, at least 10 μm, at least 11 μm, at least 12 μm, at least 13 μm, at least 14 μm, at least 15 μm, at least 16 μm, and at least 17 μm. or more, 18 μm or more, 19 μm or more, 20 μm or more, 21 μm or more, 22 μm or more, 23 μm or more, or 24 μm or more, or 45 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, 29 μm or less, 28 μm or less, 27 μm or less, 26 μm or less, 25 μm or less, 24 μm or less, 23 μm or less, 22 μm or less, 21 μm or less, 20 μm or less, 19 μm or less, 18 μm or less, 17 μm or less, 16 μm Hereinafter, it may be 15 μm or less, 14 μm or less, 13 μm or less, or 12 μm or less, but is not limited thereto.

In one example, in order to ensure durability of the cover dust laminate, especially high-temperature reliability, a PVA polarizer containing a zinc component may be used as the polarizer. In the above, examples of the zinc component include zinc and/or zinc ions. The PVA polarizer may also contain potassium components such as potassium or potassium ions as additional components. By using a polarizer containing these ingredients, it is possible to provide a cover dust laminate that maintains stable durability even under high temperature conditions.

The content of the zinc component can be further adjusted. In one example, the content of zinc (Zn) contained in the PVA polarizer may be in the range of 500 mg/kg to 1000 mg/kg. In other examples, the content is 550 mg/kg or more, 600 mg/kg or more, 650 mg/kg or more, 700 mg/kg or more, 710 mg/kg or more, 720 mg/kg or more, 730 mg/kg or more, and 740 mg. /kg or more, 750 mg/kg or more, 760 mg/kg or more, 770 mg/kg or more, 780 mg/kg or more, 790 mg/kg or more, or 800 mg/kg or more, or 990 mg/kg or less, 980 mg/ kg or less, 970 mg/kg or less, 960 mg/kg or less, 950 mg/kg or less, 940 mg/kg or less, 930 mg/kg or less, 920 mg/kg or less, or 910 mg/kg or less. The zinc (Zn) content is measured by measuring the weight (mg) of zinc (Zn) contained in the PVA polarizer based on 1 kg of weight.

The content of potassium component contained in the PVA polarizer may be 0.35% by weight to 0.7% by weight. In other examples, the content of the potassium (K) component is 0.36% by weight or more, 0.37% by weight or more, 0.38% by weight or more, 0.39% by weight or more, 0.40% by weight or more, 0.41% by weight or more, 0.42% by weight or more, 0.43% by weight. or more than 0.44% by weight, more than 0.45% by weight, more than 0.46% by weight, more than 0.47% by weight, more than 0.48% by weight or more than 0.49% by weight, or less than 0.69% by weight, less than 0.68% by weight, less than 0.67% by weight, 0.66% by weight. % or less, 0.65 weight% or less, 0.64 weight% or less, 0.63 weight% or less, 0.62 weight% or less, 0.61 weight% or less, 0.60 weight% or less, 0.59 weight% or less, 0.58 weight% or less, 0.57 weight% or less, 0.56 weight % or less, 0.55 weight% or less, 0.54 weight% or less, 0.53 weight% or less, 0.52 weight% or less, 0.51 weight% or less, 0.5 weight% or less, or 0.49 weight% or less. The content of the potassium (K) component is expressed as a percentage by weight of the potassium (K) component contained therein compared to 100 parts by weight of the PVA polarizer.

In the above description, the content of zinc and/or potassium components can be measured in the following manner. First, dissolve about 0.1 g of the polarizer in 2 mL of nitric acid aqueous solution with a concentration of about 65% by weight at room temperature, then dilute it with water (Deionized water) to 40 mL, and then use ICP-OES (Optima 5300) to determine the zinc (Zn) contained in the polarizer. The weight of and potassium (K) can be measured respectively.

Since the cover dust laminate including the polarizer containing zinc and/or potassium in the above range has excellent resistance to redness, there is no or minimal change in transmittance.

For example, the cover dust laminate containing zinc (Zn) and potassium (K) in the above weight range in the polarizer has a change in single transmittance (ΔT _s ) according to Equation 1 below after a heat resistance test. The absolute value of may be 10% or less. In this specification, the term single transmittance refers to the average of the transmittance of the absorption axis and the transmittance of the transmission axis. In the above, the single transmittance may be the result of measuring light in the visible light range, for example, light in the range of approximately 380 nm to 780 nm using a JASCO V-7100 spectrophotometer.

[Formula 1]

△T _s = T _a - T _i

In Equation 1, △T _s is the change in single transmittance, T _a is the single transmittance after the heat resistance test, and T _i may be the initial single transmittance before the heat resistance test.

In the above, the heat resistance test may mean a test in which the cover dust laminate is maintained at about 110°C for about 1000 hours.

In other examples, the absolute value of the change in single transmittance (△T _s ) is 9% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4.9% or less, 4.8% or less, 4.7% or less, 4.6% or less. or less, 4.5% or less, 4.4% or less, 4.3% or less, 4.2% or less, 4.1% or less, 4% or less, 3.9% or less, 3.8% or less, 3.7% or less, 3.6% or less, 3.5% or less, 3.4% or less, 3.3% or less, 3.2% or less, 3.1% or less, 3% or less, 2.9% or less, 2.8% or less, 2.7% or less, 2.6% or less, 2.5% or less, 2.4% or less, 2.3% or less, 2.2% or less, 2.1% or less, 1.9% or less, 1.8% or less, 1.7% or less, 1.6% or less, 1.5% or less, 1.4% or less, 1.3% or less, 1.2% or less, 1.1% or less, 1.0% or less, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, 0.5% or less, 0.4% or less, 0.3% or less, 0.2% or less, 0.1% or less or 0%, or 1% or more, 1.5% or more, 2.0% or more, 2.5% or more, or 3.0% It could be more than that. Ideally, as there is no change in the transmittance, there is no redundancy. Therefore, the absolute value of the amount of change (ΔT _s ) may preferably be 0%, and in other examples, may be approximately 0% or more.

Additionally, a cover dust laminate containing zinc and/or potassium in the above range may have optically controlled properties. For example, the cover dust laminate may satisfy Equations 2 and/or 3 below.

[Formula 2]

-b/a = 2.3 to 3.5:

[Formula 3]

0 < 1000 × (y - x) ≤ 3

In Equation 2 and/or 3, b is the b value of the CIE color space of the cover dust laminate, a is the a value of the CIE color space of the cover dust laminate, and x is the CIE color space of the cover dust laminate. is the X value, and y may be the Y value of the CIE color space of the cover dust laminate.

In this specification, the terms color coordinates a and b may refer to a and b coordinates in the CIE (INTERNATIONAL COMMISSION OF ILLUMINATION) Lab color space. The more the color leans towards green, the more negative the a value becomes, and the more the color leans towards red or purple, the more positive the a value becomes. Additionally, the more biased toward blue, the more negative the b value can be, and the more biased toward yellow, the more positive the b value can be.

In this specification, the terms The values of x and y are values calculated from A smaller difference between x and y derived by Equation 4 below indicates a chromaticity closer to neutral white, and a larger difference between x and y indicates that the color may be biased toward a specific color.

[Formula 4]

x = X/(X+Y+Z)

y = Y/(X+Y+Z)

In the present application, the polarizer may have a ratio (-b/a) of the -a value and the b value in Equation 2 of about 2.3 or more and 3.5 or less. Other examples include 2.4 or greater, 2.5 or greater, 2.6 or greater, 2.7 or greater, 2.8 or greater, 2.81 or greater, 2.82 or greater, 2.83 or greater, 2.84 or greater, 2.85 or greater, 2.86 or greater, 2.87 or greater, 2.88 or greater, 2.89 or greater, 2.90 or greater, or 2.91 or greater. or 2.92 or less, 3.49 or less, 3.48 or less, 3.47 or less, 3.46 or less, 3.45 or less, 3.44 or less, 3.43 or less, 3.42 or less, 3.41 or less, 3.40 or less, 3.39 or less, 3.38 or less, 3.37 or less, 3.36 or less, 3.35 or less, 3.34 or less, 3.33 or less, 3.32 or less, 3.31 or less, 3.30 or less, 3.29 or less, 3.28 or less, 3.27 or less, 3.26 or less, 3.25 or less, 3.24 or less, 3.23 or less, 3.22 or less, 3.21 or less, 3.20 or less, 3.19 or less, 3.18 or less , 3.17 or less, 3.16 or less, 3.15 or less, 3.14 or less, 3.13 or less, 3.12 or less, 3.11 or less, 3.10 or less, 3.09 or less, 3.08 or less, 3.07 or less, 3.06 or less, 3.05 or less, 3.04 or less, 3.03 or less, 3.02 or less, 3.01 or less. It may be 3.00 or less, 2.99 or less, 2.98 or less, 2.97 or less, 2.96 or less, 2.95 or less, 2.94 or less, 2.93 or less, 2.92 or less, 2.91 or less, or 2.9 or less.

By controlling the range of -b/a values in Equation 2 as above, the so-called redness phenomenon is not caused even when driven and/or maintained in very harsh conditions without appearing yellowish or blueish. It is possible to provide a cover dust laminate that does not emit light, and the cover dust laminate can be applied to a head-up display to provide a head-up display capable of realizing clear image quality.

In the present application, the polarizer may have a value of 1000 × (y - x) in Equation 3 that exceeds about 0 and is 3 or less. In other examples, the value is greater than 0.1, greater than 0.2, greater than 0.3, greater than 0.4, greater than 0.5, greater than 0.6, greater than 0.7, greater than 0.8 or greater than 0.9, or less than or equal to 2.9, less than or equal to 2.8, less than or equal to 2.7, less than or equal to 2.6, less than or equal to 2.5, or less than or equal to 2.4. , 2.3 or less, 2.2 or less, 2.1 or less, 2 or less, 1.9 or less, 1.8 or less, 1.7 or less, 1.6 or less, 1.5 or less, 1.4 or less, 1.3 or less, 1.2 or less, 1.1 or less, or 1.0 or less. By controlling the value of 1000

When the light emitted from the image generating device passes through the cover dust laminate that satisfies Equation 2 and/or 3 above to form a screen, a neutral white or black visual sensation can be achieved, thereby providing clearer image quality. It can provide the desired effect, such as being able to do it.

When the cover dust laminate of the present application has the above characteristics, it is possible to prevent, alleviate, alleviate, suppress and/or delay oxidation even when driven or maintained under very harsh conditions (e.g., very high temperature conditions). It is possible to provide a cover dust laminate that does not cause the so-called redness phenomenon, and when the cover dust laminate is applied to a head-up display, it is possible to prevent redness of internal components such as an image generating device.

The cover dust laminate of the present application may not include a reflective polarizer. The term reflective polarizer may refer to an element that has the function of transmitting one polarization and reflecting the other polarization from incident light that vibrates in various directions. The reflective polarizer may include, for example, a Dual Brightness Enhancement Film (DBEF), a Lyotropic Liquid Crystal (LLC) layer, or a wire grid polarizer.

Since the cover dust laminate including the reflective polarizer reflects light vibrating in a specific direction to the outside, it can play a role in blocking external light, but especially when applied to a vehicle head-up display, which will be described later, the reflection There may be a problem that it is difficult to achieve clear image quality because the light is incident on the driver's field of view.

Therefore, the cover dust laminate of the present application may be a cover dust laminate that includes an absorptive polarizer but does not include a reflective polarizer, through which clear image quality can be realized.

However, since the absorption-type polarizer is particularly vulnerable to high temperatures, high-temperature durability may be a problem when an absorption-type polarizer rather than a reflection-type polarizer is applied, such as the cover dust laminate of the present application.

Therefore, the cover dust laminate of the present application can provide a cover dust laminate with excellent high temperature durability by including a polyvinyl alcohol absorption type polarizer containing zinc and/or potassium within a certain range as described above. In addition, by asymmetrically designing the moisture permeability between the upper protective layer and/or the protective substrate and the lower protective layer, which will be described later, it is possible to provide a cover dust laminate with superior high-temperature durability while realizing clear image quality.

This application may be a cover dust laminate in which a protective substrate is attached to the upper direction of the absorption-type polarizer. As used herein, the term protective substrate may refer to a layer having a surface pencil hardness of 0.5H or more. The pencil hardness can be measured by drawing a pencil lead on the surface of the protective substrate at an angle of 45 degrees and a load of 500 g at a temperature of about 25° C. and a relative humidity of 50% using a general pencil hardness measuring equipment. Pencil hardness can be measured by gradually increasing the hardness of the pencil lead until defects such as indentations, scratches, or ruptures are identified on the surface of the protective substrate. In other examples, the pencil hardness of the protective substrate is about 0.6H or higher, 0.7H or higher, 0.8H or higher, 0.9H or higher, 1H or higher, 2H or higher, 3H or higher, or 4H or higher, or 10H or lower, 9H or lower, 8H or lower, 7H or lower, It may be 6H or less, 5H or less, 4H or less, 3H or less, or 2H or less.

The protective substrate is not limited as long as it has a surface pencil hardness in the above range. For example, it may be a glass substrate, a polymer film with a hard coating layer formed on the upper side, and the hard coating layer may be a known material. there is.

The polymer film is, for example, a polyolefin resin film such as a polycarbonate resin film, a cyclic polyolefin resin film having a cyclo or norbornene structure, a cellulose resin film such as triacetylcellulose, polyethylene terephthalate, polyethylene naphthalate, etc. It may be a polyester resin film, polyethersulfone resin film, polysulfone resin film, polyamide resin film, polyimide resin film, (meth)acrylic resin film, polystyrene resin film, or polyvinyl alcohol resin film.

The thickness of the protective substrate may be, for example, in the range of 50 μm to 1200 μm. In other examples, at least 100 μm, at least 150 μm, at least 200 μm, at least 250 μm, at least 300 μm, at least 350 μm, at least 400 μm, at least 450 μm, at least 500 μm, at least 550 μm, at least 600 μm, at least 650 μm or more than 700 μm, more than 750 μm, more than 800 μm, more than 850 μm, more than 900 μm, or more than 950 μm, or less than or equal to 1150 μm, less than or equal to 1100 μm, less than or equal to 1050 μm, less than or equal to 1000 μm, less than or equal to 950 μm, or less than or equal to 900 μm, 850 μm or less, 800 μm or less, 750 μm or less, 700 μm or less, 650 μm or less, 600 μm or less, 550 μm or less, 500 μm or less, 450 μm or less, 400 μm or less, 350 μm or less, 300 μm or less, 250 μm Hereinafter, it may be 200 μm or less, 150 μm or less, or 100 μm or less, but is not limited thereto.

By attaching the above protective substrate to the upper direction of the polarizer, the cover dust laminate can be protected from external shock.

For example, the cover dust laminate of the present application may additionally include a protective layer (hereinafter referred to as a lower protective layer) in a downward direction of the polarizer. A film having excellent transparency, mechanical strength, and thermal stability may be used as the lower protective layer.

Examples of such films include polyolefin resin films such as cyclic polyolefin resins having a cyclo or norbornene structure, cellulose resin films such as triacetylcellulose, polyester resin films such as polyethylene terephthalate and polyethylene naphthalate, and polyether resin films. Examples include sulfone resin films, polysulfone resin films, polycarbonate resin films, polyamide resin films, polyimide resin films, (meth)acrylic resin films, polystyrene resin films, and polyvinyl alcohol resin films.

In one example, the thickness of the lower protective layer may range from 10 μm to 90 μm. In other examples, it is at least 15 μm, at least 20 μm, at least 25 μm, at least 30 μm, at least 35 μm, at least 40 μm, at least 45 μm, at least 50 μm, at least 55 μm, or at least 60 μm, or at least 80 μm, at least 75 μm. Hereinafter, it may be 70 μm or less, 65 μm or less, 60 μm or less, or 55 μm or less, but is not limited thereto.

If the moisture permeability of the lower protective layer is low, the moisture in the polarizer cannot be properly discharged to the outside, which may cause the polarizer to become saturated. Therefore, the lower protective layer constituting the cover dust laminate of the present application has a high moisture permeability. It may be desirable to have .

In the present application, the moisture permeability of the lower protective layer may be 1 g/(100 in ² × day) or more in one example. In the above, the term moisture permeability may mean the weight of water vapor passing through the protective layer with an area of 100 in ² for 1 day (24 hours) under specified temperature and humidity, and can be measured using a moisture permeability tester (Labthink, W3/0120). The moisture permeability of the protective layer can be measured under the conditions described later.

If the moisture permeability of the lower protective layer is less than 1g/(100in ² It may be desirable for the lower protective layer to have a moisture permeability of 1 g/(100 in ² × day) or more.

More specifically, the PVA polarizer is generally highly hydrophilic, so it is very difficult to completely control moisture during the process of laminating the protective substrate and/or protective layer. On the other hand, the PVA polarizer undergoes a reaction such that KI ₅ contained in the PVA polarizer is decomposed into I ₂ and KI ₃ and/or KI ₃ is decomposed into I ₂ and I by moisture in a high temperature/high humidity environment, for example. As this occurs, polarization may be broken and reddening may occur.

Therefore, among the above examples, cellulose resin films such as triacetylcellulose film, polycarbonate resin films, (meth)acrylic resin films, polyester resin films, etc., which have relatively high moisture permeability, may be more preferable.

The cover dust laminate of the present application applies a lower protective layer of 1g/(100in ² can be prevented.

The upper limit of the moisture permeability of the lower protective layer is not particularly limited, but considering the possibility of moisture entering the polarizer from the outside, in one example, it may be preferable to be 100 g/(100 in ² × day) or less.

In other examples, the moisture permeability of the lower protective layer is 2 g/(100in ² ×day) or more, 3 g/(100in ² ×day) or more, 4 g/(100in ² ×day) or more, 5 g/(100in ² ×day) or more, 5.1 g/(100in ² ×day) or more, 5.2 g/(100in ² ×day) or more, 5.3 g/(100in ² ×day) or more, 5.4 g/(100in ² ×day) or more, 5.5 g/(100in ² ×day) or more, 5.6 g/(100in ² ×day) or more, 5.7 g/(100in ² ×day) or more, 5.8 g/(100in ² ×day) or more, 5.9 g/(100in ² × ^{day )} or more ^than 6.0 g/(100in ² /(100in ² ×day) or less, 50 g/(100in ² ×day) or less, 40 g/(100in ² ×day) or less, 30 g/(100in ² ×day) or less, 20 g/(100in ² ×day) or less ) or less, 10 g/(100in ² ×day) or less, 9.0 g/(100in ² ×day) or less, or 8.0 g/(100in ² ×day) or less.

The cover dust laminate of the present application has excellent high-temperature durability, such as being able to provide clear image quality even when maintained and/or driven at high temperatures when applied to a head-up display by applying a lower protective layer with high moisture permeability as described above. You can have

In another example, the present application may be a cover dust laminate 100 that additionally includes an upper protective layer 121 between the protective substrate 130 and the absorption-type polarizer 110, as shown in FIG. 3 . As the upper protective layer, a resin film or a liquid crystal layer having excellent transparency, mechanical strength, and thermal stability may be used.

Examples of the above films include polyolefin resin films such as cyclic polyolefin resins having a cyclo or norbornene structure, cellulose resin films such as triacetylcellulose, polyester resin films such as polyethylene terephthalate and polyethylene naphthalate, and polyether resin films. Examples include sulfone resin films, polysulfone resin films, polycarbonate resin films, polyamide resin films, polyimide resin films, (meth)acrylic resin films, polystyrene resin films, and polyvinyl alcohol resin films.

In one example, the thickness of the upper protective layer may range from 10 μm to 90 μm. In other examples, it is at least 15 μm, at least 20 μm, at least 25 μm, at least 30 μm, at least 35 μm, at least 40 μm, at least 45 μm, at least 50 μm, at least 55 μm, or at least 60 μm, or at least 80 μm, at least 75 μm. Hereinafter, it may be 70 μm or less, 65 μm or less, 60 μm or less, or 55 μm or less, but is not limited thereto.

In one example, the upper protective layer of the present application may be a retardation layer having an in-plane retardation. In this specification, the phase contrast layer is an optically anisotropic layer and may refer to an element capable of converting incident polarization by controlling birefringence. The phase difference layer may have 1/4 wavelength phase retardation characteristics or 1/2 wavelength phase retardation characteristics. In this specification, the n-wavelength phase retardation characteristic may mean a characteristic that can retard the phase of incident light by n times the wavelength of the incident light, within at least some wavelength range. Therefore, the 1/4 wavelength phase retardation characteristic may mean a characteristic that can retard the phase of incident light by 1/4 times the wavelength of the incident light within at least some wavelength range, and the 1/2 wavelength phase retardation The characteristic may refer to a characteristic that can retard the phase of incident light by 1/2 the wavelength of the incident light, within at least some wavelength range.

A polymer layer or a liquid crystal layer may be applied as the upper protective layer as the retardation layer. Examples of the polymer layer include, for example, cyclic polyolefin resins having the above-described cyclo or norbornene structures, cellulose resins such as triacetylcellulose, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, and polyether sulfone. A film that imparts birefringence by stretching or shrinking resin, polysulfone resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, (meth)acrylic resin, polystyrene resin, or polyvinyl alcohol resin under appropriate conditions. can be used The liquid crystal layer may include a film in which liquid crystal molecules are aligned and polymerized. The liquid crystal molecules may be polymerizable liquid crystal molecules. As used herein, a polymerizable liquid crystal molecule may refer to a molecule that includes a portion capable of exhibiting liquid crystallinity, for example, a mesogen skeleton, and one or more polymerizable functional groups. In addition, including polymerizable liquid crystal molecules in a polymerized form may mean that the liquid crystal molecules are polymerized to form a skeleton such as the main chain or side chain of the liquid crystal polymer within the liquid crystal film.

In this specification, the term in-plane phase difference (R _in ) is calculated using Equation 5 below.

[Formula 5]

R _in = d × (n _x -n _y )

In Equation 5, R _in is the in-plane retardation, d is the thickness of the upper protective layer, and n _x and n _y are the refractive indices in the x-axis and y-axis directions, respectively. In this specification, the terms x-axis and y-axis refer to a direction parallel to the in-plane slow axis of the upper protective layer, and the y-axis refers to a direction parallel to the in-plane fast axis of the upper protective layer, unless otherwise specified. , the x-axis and y-axis may be perpendicular to each other in the plane.

In the present application, the in-plane retardation (R _in ) of the upper protective layer for light of 550 nm wavelength may be, for example, 100 nm or more and 400 nm or less, and in other examples, 110 nm or more, 120 nm or more, 130 nm or more, 140 nm or more, 150 nm or more, Above 160nm, above 170nm, above 180nm, above 190nm, above 200nm, above 210nm, above 220nm, above 230nm, above 240nm, above 250nm, above 260nm, above 270nm, above 280nm, above 290nm, above 300nm, above 310nm, above 320nm , 330nm or more, 340nm or more, 350nm or more, 360nm or more, 370nm or more, 380nm or more or 390nm or less, or 390nm or less, 380nm or less, 370nm or less, 360nm or less, 350nm or less, 340nm or less, 330nm or less, 320nm or less, 310nm or less, 300nm Below, 290nm or below, below 280nm, below 270nm, below 260nm, below 250nm, below 240nm, below 230nm, below 220nm, below 210nm, below 200nm, below 190nm, below 180nm, below 170nm, below 160nm, below 150nm, below 140nm, It may be 130 nm or less, 120 nm or less, 110 nm or less, 100 nm or less, 90 nm or less, 80 nm or less, 70 nm or less, 60 nm or less, 50 nm or less, 40 nm or less, 30 nm or less, 20 nm or less, 10 nm or less, or 0 nm or less.

The cover dust laminate of the present application may not include an adhesive layer, an adhesive layer, and/or a release film in the outermost layer toward the bottom of the absorption-type polarizer.

Conventionally, there has been a polarizing plate in which a layer with low moisture permeability is disposed on one side of an absorption-type polarizer and a layer with high moisture permeability is disposed on the other side. However, by having a structure in which a pressure-sensitive adhesive layer, an adhesive layer, and/or a release film exist on the outermost layer of the surface on which the high moisture permeability layer is disposed, ultimately, for example, the polarizing plate is attached to other members such as an image generating device. It was a closed structure that was attached to prevent the inflow and outflow of moisture through both sides of the polarizer.

The cover dust laminate of the present application, unlike the conventional polarizing plate as described above, disposes a lower protective layer with a high moisture permeability, for example, a moisture permeability of 1 g/(100 in ² × day) or more, in the downward direction of the absorption-type polarizer. , it may have a structure in which no adhesive layer, adhesive layer, and/or release film exist in the outermost layer toward the bottom of the absorption-type polarizer. That is, the cover dust laminate of the present application may not include a layer with a moisture permeability of less than 1 g/(100 in ² × day) in the lower direction of the absorption-type polarizer.

Since the cover dust laminate of the present application has the structure described above, moisture can be easily discharged toward the bottom of the absorption-type polarizer, especially in a high-temperature environment. Accordingly, when applied to a head-up display to be described later, clear image quality can be realized without redness even when driven and/or maintained at high temperatures, and a cover dust laminate with excellent high temperature durability can be provided.

The cover dust laminate of the present application may have various types of structures. For example, Figure 2 shows that in the structure of the most basic cover dust laminate 100, a protective substrate 130 is formed in the upper direction of the absorption-type polarizer 110, and a lower protective layer 122 is formed in the lower direction of the polarizer. This shows the formed structure. However, the protective layer may be formed on one or both sides of the polarizer. For example, as shown in FIG. 3, the upper protective layer 121 is introduced between the protective substrate 130 and the absorbing polarizer 110. It can be expressed.

The structure of FIGS. 2 and 3 is an example of the present application, and the cover dust laminate of the present application may have various other structures.

This application also relates to a Head Up Display including the cover dust laminate. The head-up display includes an image generating device; and a cover dust laminate, wherein an image emitted from the image generating device passes through the cover dust laminate; And it may be a head-up display on which a cover dust laminate is disposed.

In the present application, the image generating device may be an image generating device that emits an image in a linearly polarized state. For example, when using an LCD (Liquid Crystal Display) or OLED (Organic Light Emitting Diode) as the image generating device, a polarizing film is attached to the image generating device so that the emitted optical signal is in the form of linearly polarized light having a certain polarization direction. , and through this, the signal loss of optical signals transmitted to various components can be reduced as much as possible.

The present application also provides that the smaller angle between the vibration direction of linearly polarized light emitted from the image generating device and incident on the cover dust laminate and the absorption axis of the polarizer of the cover dust laminate is, for example, 50 degrees to 80 degrees. It may be a head-up display 10 in which the image generating device 20 and the cover dust laminate 100 are arranged within the range of degrees.

The angle is based on the position at which the minimum luminance is measured when the luminance of light transmitted through the cover dust laminated body 100 is measured while rotating the cover dust laminated body 100 within the head-up display 10 (0 °), which may be an angle measured clockwise or counterclockwise.

In other examples, the angle is 51 degrees or more, 52 degrees or more, 53 degrees or more, 54 degrees or more, 55 degrees or more, 56 degrees or more, 57 degrees or more, 58 degrees or more, 59 degrees or more, or 60 degrees or more, or 79 degrees. Below, it may be 78 degrees or less, 77 degrees or less, 76 degrees or less, 75 degrees or less, 74 degrees or less, 73 degrees or less, 72 degrees or less, 71 degrees or less, or 70 degrees or less.

In the present application, the head-up display may additionally include light control means. In this specification, the term light control means is a device that directs the light signal emitted from the image generating device to the windshield on which the image is displayed after passing through the cover dust laminate, for example, a reflector and/or a beam splitter, etc. You can.

In one example, the head-up display 10 includes an image generating device 20 and the cover dust laminate 100 as shown in FIG. 4, and light 200 emitted from the image generating device is transmitted through a beam splitter 30. ), some of the emitted light becomes reflected light 202 reflected in the direction of the reflector 40, and the remaining part becomes transmitted light 201 and passes through the cover dust laminate 100, thereby creating a wind It may be a head-up display that can implement two screens independent of the shield 50. As used herein, the term beam splitter refers to a device that divides one light source into two light sources. Therefore, when one light source passes through the beam splitter, part of it is transmitted and the other part is reflected and follows two different light paths. You can move.

As described above, the head-up display of the present application can implement two independent screens in one example. The two independent screens may be implemented in contact with each other, and therefore, it may be required that there is little difference in luminance between the two screens. The present application arranges the angle between the polarization direction of the linearly polarized light emitted from the image generating device and the absorption axis of the polarizer of the cover dust laminate as described above, thereby providing a device with clear image quality with almost no difference in luminance between two independent screens. A head-up display can be implemented.

In this specification, the term luminance refers to the light density in a specific direction, that is, the amount of light passing through a certain area and entering at a certain solid angle, and 'little difference in luminance' refers to the luminance of two independent screens. This means not only the case where is the same, but also the case where the luminance ratio is 0.5 to 1.5 or less. In other examples, the ratio may be greater than or equal to 0.52, greater than or equal to 0.54, greater than or equal to 0.56, greater than or equal to 0.58, greater than or equal to 0.60, greater than or equal to 0.62, greater than or equal to 0.64, greater than or equal to 0.66, or greater than or equal to 0.67, or greater than or equal to 1.45, greater than or equal to 1.4, greater than or equal to 1.35, or greater than or equal to 1.3. If the luminance ratio of the two independent screens satisfies the above range, for example, the driver may perceive the two independent screens as one screen.

The present application includes a cover dust laminate having the above-described characteristics, and controls the angle formed between the vibration direction of linearly polarized light emitted from an image generating device and the absorption axis of the polarizer of the cover dust laminate to the above range, such as high temperature, etc. Even under harsh conditions, red-lighting does not occur, clear picture quality can be realized, and when displaying two independent screens, a head-up display with an appropriate luminance ratio of each screen can be provided.

In the present application, it is possible to provide a cover dust laminate that does not cause the so-called redness phenomenon even when driven or maintained under very harsh conditions (for example, very high temperature conditions). In addition, the cover dust laminate is applied to the head-up display to prevent internal components such as the image generating device from burning, while realizing clear image quality, and when displaying two independent screens, the luminance ratio of each screen is appropriate. A head-up display can be provided.

1 is a diagram for explaining a typical structure of a head-up display.
2 and 3 are diagrams for explaining an exemplary structure of the cover dust laminate of the present application.
FIG. 4 is a diagram illustrating an exemplary structure of a head-up display capable of implementing two independent screens.

Hereinafter, the cover dust laminate, etc. will be described in more detail through examples according to the present application, but the scope of the present application is not limited to the following.

Below, each physical property of the cover dust laminate was measured in the following manner.

1. Weight measurement of zinc (Zn) and potassium (K) of polarizer

The weight of zinc (Zn) and potassium (K) present in the polarizer is measured in the following manner.

It was. First, dissolve about 0.1 g of the polarizer in an aqueous solution of nitric acid (2 mL) with a concentration of about 65% by weight at room temperature (about 25°C), then dilute it with water (Deionized water) to 40 mL, and then use ICP-OES (Optima 5300) equipment. The weight of potassium (K) and zinc (Zn) contained in the polarizer were measured, respectively.

2. CIE color coordinate measurement

Color coordinates were measured using a JASCO V-7100 spectrophotometer. The JASCO V-7100 spectrophotometer rotates the absorption axis of the polarizer to be measured from 0 degrees to 360 degrees with respect to the absorption axis of the polarizer built into the device, and measures the color coordinates (TD color coordinates) at the point where the transmittance is minimum. , This is a device that measures the color coordinates (MD color coordinates) by rotating the absorption axis of the polarizer to be measured 90 degrees clockwise at the point where the transmittance is minimum, and then derives a representative value of the color coordinates based on each measured value. The color coordinates described in the examples of this specification are the color coordinates confirmed by the JASCO V-7100 spectrophotometer.

3. Group transmittance measurement

The single transmittance of the cover dust laminate was measured using a JASCO V-7100 Spectrophotometer. The JASCO V-7100 Spectrophotometer is an instrument that measures the single transmittance of the cover dust laminate within the range of 380 to 780 nm and derives a representative value for the wavelength range, and in this embodiment, The group transmittance confirmed in the JASCO V-7100 spectrophotometer was described.

4. Luminance measurement

Cover dust laminate (100), image generating device (LGE, LA080WV5) (20), beam splitter (Edmund, B-plate Beamsplitter) (30), reflector (Edmund, S-mirror) (40), wind The shield 50 was arranged as shown in FIG. 4, and the luminance of the screen displayed on the windshield 50 was measured while changing the angle of the cover dust laminate. When measuring, measure the luminance of the screen formed by reflected light 202 and the screen formed by transmitted light 201 using a two-dimensional luminance measuring device (Risa, Color one) at a location 50 cm away from the windshield 50. did.

Preparation Example 1. Preparation of polarizer (A)

A PVA (poly(vinyl alcohol)) film (M3000 grade, Japan Synthetic Co., Ltd.) with a thickness of about 30㎛ was dyed in a dyeing solution at 28°C containing 0.3% by weight of iodine (I ₂ ) and 3.0% by weight of potassium iodide (KI). It was dyed by dipping for 60 seconds. The dyed PVA film was then cross-linked by immersing it in an aqueous solution (cross-linking solution) at 35°C containing 1% by weight of boron and 3% by weight of potassium iodide (KI) for 60 seconds. Afterwards, the crosslinked PVA film was stretched at a stretching ratio of 5.4 times using the roll-to-roll stretching method. The stretched PVA film was washed by immersing it in ion-exchanged water at 25°C for 60 seconds, and then immersed in an aqueous solution at 25°C containing 2.5% by weight of zinc nitrate and 3% by weight of potassium iodide (KI) for 30 seconds. Afterwards, the PVA film was dried at a temperature of 80°C for 60 seconds to prepare a PVA polarizer. The final thickness of the manufactured polarizer was about 12㎛, the potassium content was about 0.49% by weight, and the zinc content was about 910mg/kg.

Preparation Example 2. Preparation of polarizer (B)

Except that the stretched PVA film was washed by immersing it in ion-exchanged water at 25°C for 60 seconds, and then immersed in an aqueous solution at 25°C containing 2.5% by weight of zinc nitrate and 5% by weight of potassium iodide (KI) for 30 seconds. It was prepared in the same manner as Example 1. The final thickness of the manufactured polarizer was about 12㎛, the potassium content was about 0.55% by weight, and the zinc content was about 740mg/kg.

Preparation Example 3. Preparation of polarizer (C)

Except that the stretched PVA film was washed by immersing it in ion-exchanged water at 25°C for 60 seconds, and then immersed in an aqueous solution at 25°C containing 2.5% by weight of zinc nitrate and 1% by weight of potassium iodide (KI) for 30 seconds. It was prepared in the same manner as Example 1. The final thickness of the manufactured polarizer was about 12㎛, the potassium content was about 0.29% by weight, and the zinc content was about 900mg/kg.

Preparation Example 4. Preparation of polarizer (D)

Prepared except that the stretched PVA film was washed by immersing it in ion-exchanged water at 25°C for 60 seconds, and then immersed in an aqueous solution at 25°C containing 3.5% by weight of zinc nitrate and 5% by weight of potassium iodide (KI) for 30 seconds. It was prepared in the same manner as Example 1. The final thickness of the manufactured polarizer was about 12㎛, the potassium content was about 0.59% by weight, and the zinc content was about 1030mg/kg.

Preparation Example 5. Preparation of polarizer (E)

Prepared except that the stretched PVA film was washed by immersing it in ion-exchanged water at 25°C for 60 seconds, and then immersed in an aqueous solution at 25°C containing 4.5% by weight of zinc nitrate and 5% by weight of potassium iodide (KI) for 30 seconds. It was prepared in the same manner as Example 1. The final thickness of the manufactured polarizer was about 12㎛, the potassium content was about 0.53% by weight, and the zinc content was about 1160mg/kg.

Preparation Example 6. Preparation of internalized layer (A') material

Trimethylolpropane triacrylate (TMPTA) was applied as a binder, and hollow silica particles were applied to manufacture an internalization layer. As the hollow silica particles, particles with D10, D50, and D90 particle diameters of 32.1 nm, 62.6 nm, and 123.4 nm were used, respectively. In this case, the average pore size measured by TEM after forming the internalization layer was approximately 38.3 nm, and the particle diameter was approximately 53 nm. The binder, the hollow silica particles, the fluorine-containing compound (RS-90, DIC) and the initiator (Irgacure 127, Ciba) were mixed at a weight ratio of 31:65:0.1:3.9 based on solid content (binder: hollow silica particles: A coating solution was prepared by diluting a fluorine compound: initiator) in MIBK (methyl isobutyl ketone), a solvent.

Example 1.

A general optical water-based adhesive layer (thickness: 100 nm) was applied to the polarizer (A) obtained in Preparation Example 1, and a cycloolefin polymer film (Zeon) with a thickness of approximately 30 μm was attached. Separately, an internalized layer was formed on a triacetylcellulose film (Hyosung) with a thickness of approximately 60 μm. For the internalization layer, the internalization layer (A') material of Preparation Example 6 was coated on the triacetylcellulose film with a Mayer bar, dried at about 60°C for about 1 minute, and then irradiated with ultraviolet rays (252mJ/cm ² ) to obtain the final thickness. It was formed to be about 450 nm. Subsequently, the laminate of the triacetylcellulose film with the internal layer formed was attached to the laminate of the cycloolefin polymer film and the polarizer (A) prepared above using the same water-based adhesive (thickness: 100 nm). As a result, a cover dust laminate having a structure in which the upper protective layer (triacetylcellulose film) / internal layer / adhesive layer / polarizer (A) / adhesive layer / lower protective layer (cycloolefin polymer film) was sequentially laminated was manufactured.

Example 2.

Proceeded in the same manner as Example 1, except that the polarizer (B) of Preparation Example 2 was used.

Comparative Example 1.

Proceeded in the same manner as Example 1, except that the polarizer (C) of Preparation Example 3 was used.

Comparative Example 2.

Proceeded in the same manner as Example 1, except that the polarizer (D) of Preparation Example 4 was used.

Comparative Example 3.

Proceeded in the same manner as Example 1, except that the polarizer (E) of Preparation Example 5 was used.

The characteristics of the cover dust laminate formed in each of the above examples are listed in Table 1 below.

In Table 1 below, △T _s is the absolute value of the difference between the initial single transmittance _Ti of the cover dust laminate and the single transmittance T _a after maintaining the laminate in an oven at 110°C for 1000 hours.

Example 3.

The cover dust laminate 100 formed in Example 1, an image generating device (LGE, LA080WV5) 20, a beam splitter (Edmund, B-plate Beamsplitter) 30, and a reflector (Edmund, S-mirror) ) (40) is arranged as shown in FIG. 4, the cover dust laminate is rotated, and the vibration direction of the linearly polarized light incident on the cover dust laminate is aligned with the absorption axis of the absorption-type polarizer 110 of the cover dust laminate. It was arranged so that the smallest angle among the angles formed was 70 degrees.

After that, the luminance of the screen formed by the reflected light 202 and the screen formed by the transmitted light 201 are measured respectively according to the above-described luminance measurement method, and then the luminance of the screen formed by the reflected light 202 is measured by the transmitted light 201. The luminance ratio divided by the luminance of the screen formed by is summarized and listed in [Table 2] below.

Examples 4 to 8.

Except that the smaller angle between the type of cover dust laminate, the direction of vibration of linearly polarized light incident on the cover dust laminate, and the absorption axis of the polarizer of the cover dust laminate is applied as shown in [Table 2] below. Proceeded in the same way as Example 3.

10: Head-up display
100: Cover dust laminate
110: absorption polarizer
121: upper protective layer 122: lower protective layer
130: protection substrate
20: Image generating device 200: Emitted light 201: Transmitted light 202: Reflected light
30: Beam splitter
40: reflector
50: Windshield

Claims (15)

A cover dust laminate including a polyvinyl alcohol absorption type polarizer containing a zinc component and a potassium component,
The content of the zinc component contained in the polyvinyl alcohol absorption type polarizer is within the range of 500 mg/kg to 1000 mg/kg, and the content of the zinc component is based on the zinc contained therein based on 1 kg of weight of the polyvinyl alcohol absorption type polarizer. The weight (mg) of the ingredient is measured,
The content of the potassium component contained in the polyvinyl alcohol absorption type polarizer is within the range of 0.35% by weight to 7% by weight, and the content of the potassium component is based on the amount of potassium component contained therein compared to 100 parts by weight of the polyvinyl alcohol absorption type polarizer. The weight ratio is expressed as a percentage,
The cover dust laminate is a cover dust laminate that satisfies the following equations 2 and 3:
[Formula 2]
-b/a = 2.3 to 3.5:
[Formula 3]
0 < 1000 ×(y - x) ≤ 3 :
In Equations 2 and 3, b is the b value of the CIE color space of the cover dust laminate, a is the a value of the CIE color space of the cover dust laminate, and x is X of the CIE color space of the cover dust laminate. value, and y is the Y value of the CIE color space of the cover dust laminate. The cover dust laminate according to claim 1, wherein the absolute value of the change in single transmittance (ΔT _s ) according to Equation 1 below is within 10%.
[Formula 1]
△T _s = T _a - T _i
In Equation 1, △T _s is the change in single transmittance, T _a is the single transmittance after the heat resistance test, and T _i is the initial single transmittance before the heat resistance test. delete The cover dust laminate according to claim 1, which does not include a reflective polarizer. The cover dust laminate according to claim 1, wherein a protective substrate is attached to the upper portion of the absorption-type polarizer. The cover dust laminate of claim 5, further comprising a lower protective layer in a downward direction of the absorption-type polarizer. The cover dust laminate of claim 6, further comprising an upper protective layer between the protective substrate and the absorption-type polarizer. The cover dust laminate of claim 7, wherein the upper protective layer has an in-plane retardation. The cover dust laminate according to claim 7, wherein the in-plane retardation of the upper protective layer for light with a wavelength of 550 nm is in the range of 100 to 400 nm. The cover dust laminate according to claim 1, wherein no adhesive layer, adhesive layer, or release film is present in the outermost layer toward the bottom of the absorption-type polarizer. image generating device; and a cover dust laminate according to claim 1, wherein the image generating device includes an image emitted from the image generating device to transmit the cover dust laminate. and a head-up display on which the cover dust laminate is disposed. The head-up display according to claim 11, wherein the image generating device emits an image in a linearly polarized state. The image generating device and the cover dust laminate according to claim 12, wherein the smaller angle between the vibration direction of the linearly polarized light emitted from the image generating device and the absorption axis of the polarizer of the cover dust laminate is in the range of 50 degrees to 80 degrees. Head-up display with sieve placed. The head-up display device according to claim 11, further comprising a beam splitter, wherein the beam splitter is arranged so that an image emitted from the image generating device passes through the cover dust laminate through the beam splitter. The head-up display according to claim 11, further comprising a reflector, wherein the reflector is disposed so that an image emitted from the image generating device is reflected by the reflector and passes through the cover dust laminate.