JP6006210B2 - Polarizing element and polarizing plate - Google Patents

Description

  The present invention relates to a polarizing element and a polarizing plate using the polarizing element.

  A polarizing element is generally produced by adsorbing and orienting an iodine complex or dichroic dye, which is a dichroic dye, on a polyvinyl alcohol-based resin film. A protective film made of triacetyl cellulose or the like is bonded to at least one surface of the polarizing element via an adhesive layer to obtain a polarizing plate. Since the polarizing plate has a light transmission / shielding function, it becomes a basic component of a display device such as a liquid crystal display (LCD) together with a liquid crystal having a light switching function. The application fields of LCDs are also wide-ranging from small devices such as calculators and watches in the early days to notebook computers, word processors, liquid crystal projectors, liquid crystal televisions, car navigation systems, mobile phones, and indoor and outdoor measuring devices. It is used under a wide range of conditions: high temperature, low humidity to high humidity, low light quantity to high light quantity. Therefore, there is a demand for polarizing plates that have high polarization performance and excellent durability. A polarizing plate using an iodine complex as a dichroic dye is called an iodine polarizing plate, while a polarizing plate using a dichroic dye as a dichroic dye is called a dye polarizing plate. Of these, iodine-based polarizing plates are often used because of their excellent optical properties. The dye-based polarizing plate has a problem that the transmittance is low compared to a polarizing plate having the same degree of polarization as that of the iodine-based polarizing plate, that is, the contrast is low, but it has high heat resistance and high humidity heat durability. Because of its characteristics, it is used in color liquid crystal projectors (Patent Document 1).

  Currently, LCDFLs and other LCDs use CCFLs and high-pressure mercury lamps as light sources. Recently, light-emitting diodes (LEDs) such as Patent Document 2 and Patent Document 3 have become widespread, and white LEDs are widely used. Has been. As a polarizing plate using these light sources, a general neutral gray iodine polarizing plate which is already known is used. The iodine polarizing plate has a feature of high contrast in a wide wavelength region, and is useful for CCFLs, high-pressure mercury lamps, white LEDs, and the like.

  Further, the role of the liquid crystal panel composed of the polarizing plate and the liquid crystal is not only a function of switching light that transmits and blocks light, but also has a function of displaying an image by having a color filter in the liquid crystal panel. As this problem, there is a problem that due to the orientation direction of the liquid crystal, light leakage occurs depending on the angle at which the image is viewed and it is difficult to see the image, that is, the viewing angle is narrow. There are many types of liquid crystal such as VA type (vertical alignment type), TN type (twisted nematic type), IPS (in-plane switching type), although there are differences in the degree of viewing angle. Both methods have the problem of narrow viewing angle. In order to compensate for this narrow viewing angle, optical compensation films such as PC (polycarbonate) film, COP (cycloolefin) film, and TAC (triacetyl cellulose) film coated with dicotic liquid crystal oriented in a specific direction are widely used. It is used.

  As a display using liquid crystal technology, for example, a blue light emitting diode is used as a backlight, and instead of a color filter, a display provided with a phosphor that emits various colored lights when excited by blue light is known ( Hereinafter, it is referred to as a fluorescence excitation color conversion display). For example, it is disclosed in Patent Document 4. This type of phosphor-excited color conversion type liquid crystal display device converts the wavelength of light emitted from a backlight with a phosphor and performs desired color display using the obtained fluorescence. Unlike the color filter type liquid crystal display device, this liquid crystal display device has a feature that light use efficiency is high because there is no light absorption loss by the color filter. Further, there is no problem that the viewing angle is narrow, which has been a problem with the conventional LCD, and a high-quality image display can be obtained. As this light source, a blue light source is used in order to increase the luminous efficiency of the phosphor. As the light source in the blue region, a blue LED or a blue fluorescent tube having a maximum light emission output of 440 nm to 470 nm is used.

  In general, in a flat panel display, the in-screen contrast needs to be 50 or more over all images and all viewing angles. More preferably, the in-screen contrast needs to be 100 or more. “Intra-screen contrast” is the ratio of the brightness of the brightest pixel to the darkest pixel in a state where one image is displayed. Note that “panel contrast” that is generally used is the ratio between the luminance when displaying all white and the luminance when displaying all black. However, there are practically no images that display all white or all black. In addition, when the contrast becomes too high, the feeling of eye fatigue increases. Therefore, as a required specification of contrast based on ergonomics, “contrast in the screen” is recommended to be 50 or more, more preferably 100 or more (Non-Patent Document 1).

  The required in-screen contrast changes depending on the ambient illuminance for viewing the flat panel display. That is, the brighter the peripheral illuminance, the smaller the required in-screen contrast, and the darker the peripheral illuminance, the greater the required in-screen contrast. Table 1 shows the required in-screen contrast values when the ambient illuminance is changed from 0 to 500 lux.

As a characteristic of an average signal level ASL (Average Signal Level) or an average luminance level ALL (Average Luminance Level) of general television broadcasting, the average is about ASL 40%, ALL 20%, and the range is about ASL 20-60%, ALL 5 There is a report of about 40%. When viewing these videos on a 65-inch TV, the viewing distance is 3H (three times the distance when the TV screen height is H) under an ordinary living environment of illuminance 180lux. In this case, it has been reported that the most preferable maximum luminance for a television is 240 cd / m ² (Non-patent Document 2). Here, when the ambient illuminance of a general living room is set to 180 lux, since the in-screen contrast is 50 or more in the living room, from Table 1, the in-screen contrast must be 200 or more in the dark room. Recognize.

The condition that the in-screen contrast is the smallest is when the entire screen displays a dark image. When the darkest image is displayed, the brightness of the brightest pixel in the screen is said to be about 5% of the maximum brightness (Non-Patent Document 3). If the maximum brightness of the display of 240cd / ^{m 2,} the luminance of the brightest pixel in the screen is about 12 cd / ^{m 2.} Under this condition, in order for the in-screen contrast to be 200 or more, it is necessary to suppress the luminance of the darkest pixel in the screen to about 0.06 cd / m ² or less. That is, in order to satisfy the above condition that the brightness of the brightest pixel in the screen is 240 cd / m ² and the brightness of the darkest pixel in the screen is 0.06 cd / m ² , a panel contrast of 4,000 is required. . The panel contrast represents the ratio of the transmittance at the time of light transmission (parallel Nicol) and the transmittance at the time of light blocking (cross Nicol) when the liquid crystal panel is sandwiched between a pair of polarizing plates.

  Table 2 shows the relationship among the in-screen contrast, panel contrast, and polarizing plate contrast in the fluorescence excitation color conversion display.

  As can be seen from Table 2, when the panel contrast is 4,000, the polarizing plate contrast needs to be 6,000. The polarizing plate contrast in Table 2 is the light energy transmittance Ep in the light transmitting state (on state / polarizing plate parallel Nicol) and the light in the light blocking state (off state / polarizing plate crossed Nicol). The ratio of energy transmittance Ec is represented. The light energy transmittance Ep indicates the energy of the amount of light (blue light) incident on the phosphor layer unit area in a predetermined wavelength range in the light transmission state. Light Energy Transmittance Ec in the Blocking State Ec The energy of the amount of light (blue light) incident on the phosphor layer unit area in a predetermined wavelength range in the light blocking state.

  In the fluorescence excitation color conversion display system, blue light is incident on the phosphor to generate each color light of R, G, B, and the luminance of the display device is the spectral emission of light after being emitted by the phosphor. It is known that the spectral radiance of the light emitted from the phosphor is proportional to the incident energy of the blue light that excites the phosphor, although it is determined by a value obtained by multiplying the luminance by the visibility. Further, the effect of depolarization due to transmission through the liquid crystal panel also occurs in blue light. For the above reason, the polarizing plate contrast (Ep / Ec) due to the energy transmittance required for the pair of polarizing plates can be considered equivalent to the polarizing plate contrast (Tp / Tc) due to the spectral transmittance. Tp is the spectral transmittance (transmission at the time of parallel Nicols) when two polarizing elements are stacked in parallel with each other, and Tc is the two polarizing elements orthogonal to each absorption axis. Is the spectral transmittance (transmittance during crossed Nicols). However, since the emission wavelength of the phosphor depends on the energy band structure exhibited by the phosphor material, it is necessary to estimate the total energy of the light that excites the phosphor, rather than focusing on the intensity of the excitation light at a specific wavelength. It is.

  From the above, when the polarizing plate contrast (Ep / Ec) by light energy transmittance is set to 6,000, especially between arbitrary wavelengths in the maximum light emission output region of the backlight, the polarizing plate contrast by spectral transmittance ( Tp / Tc) needs to be higher than 6,000, and preferably the contrast (Tp / Tc) is 8,000. Further, in order to make the contrast (Ep / Ec) due to the light energy transmittance higher, it is also necessary to make the polarizing plate contrast (Tp / Tc) due to the spectral transmittance higher.

  More preferably, it is said that the contrast within the screen is equal to or greater than 100 under 300 lux. In this case, from Tables 1 and 2, the in-screen contrast in the dark room ≧ 350, the polarizing plate contrast by the energy transmittance ≧ 15,000, and the polarizing plate contrast by the spectral transmittance is particularly in the maximum light emission output region of the backlight. Between arbitrary wavelengths, a contrast of 20,000 or more is required.

  In addition, the conventional liquid crystal display device shows a luminance distribution that largely reflects the directivity of the backlight, but the fluorescence excitation color conversion display method uses isotropic light emission by a phosphor, and thus has a wide viewing angle. It is. On the other hand, the surface brightness is reduced due to the low directivity. It is said that when the full width at half maximum is changed from 30 degrees to 45 degrees at full width at half maximum, the front luminance is reduced to approximately half.

General television and video image signals are usually expressed using 16 to 235 gradations among 0 to 255 gradations that can be expressed in 8 bits. However, in the luminance expansion mode called the super white mode, up to 255 gradations can be used. In the case of all white display, when luminance of 400 cd / m ² is obtained with 235 gradations, the luminance when displaying 255 gradations in the super white mode is about 1.2 times when gamma 2.2 is set. 487 cd / m ² is obtained. Table 3 shows a comparison between the total white luminance and the maximum display luminance in the super white mode. In the fluorescence excitation color conversion display method, the most preferable luminance is 240 cd / m ² when the value of the light energy transmittance Ep in the light transmission state (parallel Nicol) of the polarizing plate is 30% or more. Recognize. In order to obtain Ep of 30% or more, the transmittance Tp at the time of parallel Nicol in the spectral transmittance must be 30% or more.

A well-known general neutral gray iodine polarizing plate has a high contrast in a wide wavelength range, but in a blue light source region having a maximum light emission output of 440 nm to 470 nm used for a fluorescence excitation color conversion display, light leakage is large. Sufficient contrast cannot be obtained and the brightness is insufficient. When used as a polarizing plate for fluorescence excitation color conversion display, maximum luminance 240cd / ^{m 2} Ep ≧ 30% to obtain, and the maximum luminance 240cd / ^{m 2} and is a polarizing plate to obtain a screen contrast more than 200 in the darkroom There has never been a polarizing plate that can achieve a contrast (Ep / Ec) of 6,000.

JP 2001-027708 A Japanese Patent No. 3585097 Japanese Patent No. 4686644 JP 2009-134275 A

SID'03 Digest p.779 IEICE Transactions, J91-A (6), pp. 630-638 (2008) JJ vol. 46, 3B, 2007, p. 1358

  As described above, in a conventional iodine-based polarizing plate known as a polarizing plate used in a fluorescence excitation color conversion display using a blue LED or a blue fluorescent tube having a maximum light emission output of 440 nm to 470 nm as a light source, However, a sufficient display image cannot be obtained due to problems such as low contrast and light leakage or low transmittance during light transmission. Accordingly, an object of the present invention is to provide a polarizing element and a polarizing plate suitable for the display, which have high contrast, little light leakage, and high transmittance when transmitting light.

  As a result of intensive studies to solve the above problems, the present inventors have found that at least a dichroic dye is contained, and in the wavelength region of 440 nm ≦ λ ≦ 470 nm, the polarization has a high contrast and a high transmittance during light transmission. It discovered that an element and a polarizing plate solved the said subject, and reached | attained this invention.

（式中Ｒ_１、Ｒ_２は各々独立に水素原子、低級アルキル基、低級アルコキシル基を示し、ｎ＝１〜３を示す）
（５）５００ｎｍ≦λ≦５６０ｎｍの波長領域において、透過率が２％以下であることを特徴とする、（１）ないし（４）のいずれか１に記載の偏光素子。
（６）２色性色素がヨウ素錯体であって、かつＴｃ(λ４６０)≦Ｔｃ(λ６００)であることを特徴とする（１）ないし（３）に記載の偏光素子。
ここでＴｃ(λ４６０)は偏光素子2枚をそれぞれの吸収軸を直交して重ねた時（クロスニコル時）の４６０ｎｍにおける分光透過率であり、Ｔｃ(λ６００)は偏光素子２枚をそれぞれの吸収軸を直交して重ねた時（クロスニコル時）の６００ｎｍにおける分光透過率である。
（７）偏光素子の少なくとも片面に支持体フィルムを設けてなる（１）ないし（６）のいずれか１に記載の偏光板。
（８）支持体フィルムの少なくとも片面がＰＥＴ(ポリエステル)フィルムである（７）に記載の偏光板。
（９）無機基板に（１）ないし（６）のいずれか１に記載の偏光素子または（７）又は（８）に記載の偏光板が積層されたことを特徴とする無機基板付偏光板。
に関するThat is, the present invention is (1) in the wavelength region of 440 nm ≦ λ ≦ 470 nm, Tp ≧ 30%, and CR ≧ 8,000 in the wavelength region between any continuous 20 nm in the wavelength region, and CR in the remaining wavelength region. A polarizing element for use in a fluorescence excitation color conversion display using a blue LED or a blue fluorescent tube having a maximum light emission output of 440 nm to 470 nm as a light source, which is ≧ 5,000 and contains at least a dichroic dye .
Here, λ represents a wavelength, Tp is a spectral transmittance (transmittance at the time of parallel Nicols) when two polarizing elements are overlapped in parallel with each other, and Tc is two polarizing elements. Is a spectral transmittance (transmission at the time of crossed Nicols) when the absorption axes are overlapped at right angles, and CR is an abbreviation of contrast and indicates a value consisting of Tp / Tc.
(2) The polarizing element according to (1), wherein Tp ≧ 30% and CR ≧ 1,500 in a wavelength region of 420 nm ≦ λ <440 nm.
(3) The polarizing element according to (1) or (2), wherein Tp ≧ 30% and CR ≧ 1,000 in a wavelength region of 470 nm <λ ≦ 490 nm.
(4) The dichroic dye contains at least one kind of dichroic dye (A) group and / or the dichroic dye (B) represented by the formula (1) (1) to (3) The polarizing element according to any one of the above.
Dichroic dye (A) group Ai. direct. Orange 26
Sea. Ai. direct. Orange 39
Sea. Ai. direct. Orange 107
Dichroic dye (B)

(Wherein R ₁ and R ₂ each independently represents a hydrogen atom, a lower alkyl group or a lower alkoxyl group, and n = 1 to 3)
(5) The polarizing element according to any one of (1) to (4), wherein the transmittance is 2% or less in a wavelength region of 500 nm ≦ λ ≦ 560 nm.
(6) The polarizing element according to any one of (1) to (3), wherein the dichroic dye is an iodine complex and Tc (λ460) ≦ Tc (λ600).
Here, Tc (λ460) is the spectral transmittance at 460 nm when two polarizing elements are stacked with their absorption axes orthogonal to each other (in crossed Nicols), and Tc (λ600) absorbs the two polarizing elements respectively. It is the spectral transmittance at 600 nm when the axes are stacked orthogonally (cross Nicol).
(7) The polarizing plate according to any one of (1) to (6), wherein a support film is provided on at least one surface of the polarizing element.
(8) The polarizing plate according to (7), wherein at least one surface of the support film is a PET (polyester) film.
(9) A polarizing plate with an inorganic substrate, wherein the polarizing element according to any one of (1) to (6) or the polarizing plate according to (7) or (8) is laminated on an inorganic substrate.
Concerning

  The polarizing element of the present invention and a polarizing plate using the polarizing element have high polarization performance in a wavelength region of 440 nm ≦ λ ≦ 470 nm, and a fluorescence excitation color conversion display using a blue LED or a blue fluorescent tube having a wavelength of 440 nm to 470 nm as a light source The polarizing plate suitable for can be provided.

Tp of spectroscopic measurement value of each wavelength every 5nm Tc of spectroscopic measurement value of each wavelength every 5 nm

BEST MODE FOR CARRYING OUT THE INVENTION

  The polarizing element of the present invention has Tp ≧ 30% in the wavelength region of 440 nm ≦ λ ≦ 470 nm, and CR ≧ 8,000 in the wavelength region between any continuous 20 nm in the wavelength region, and CR in the remaining wavelength region. ≧ 5,000. By using such a polarizing element of the present invention, sufficient brightness and contrast can be obtained in a fluorescence excitation color conversion display using a blue LED or blue fluorescent tube having a maximum light emission output of 440 nm to 470 nm as a light source. . In the display of the display, in the wavelength region of 440 nm ≦ λ ≦ 470 nm, sufficient contrast cannot be obtained with CR <8,000 in any continuous wavelength region between 20 nm and CR <5,000 in the remaining wavelength region. It is necessary that CR ≧ 8,000 in any wavelength region between 20 nm and CR ≧ 5,000 in the remaining wavelength region. Preferably, CR ≧ 10,000, more preferably CR ≧ 15,000, in at least any continuous wavelength region between 20 nm within the wavelength region of 440 nm ≦ λ ≦ 470 nm. More preferably, CR ≧ 20,000 for the wavelength region of 450 nm ≦ λ ≦ 460 nm. The contrast value can be increased by decreasing the single plate transmittance of the polarizing element, but in this case, the Tp value is also decreased and sufficient brightness cannot be obtained. When Tp <30%, sufficient brightness tends not to be obtained, and when Tp ≧ 30%, light utilization efficiency is excellent, and power consumption can be reduced. Tp ≧ 31% is preferable, and Tp ≧ 32% is more preferable.

  Furthermore, the polarizing element of the present invention preferably satisfies Tp ≧ 30% and CR ≧ 1,500 in the wavelength region of 420 nm ≦ λ <440 nm. It is preferable to control the weak light emission of the blue LED or blue fluorescent tube having a maximum light emission output of 440 nm to 470 nm on the short wavelength side. In the display of the display, the contrast is lowered when CR <1,500 in the wavelength region. Preferably, CR ≧ 1,500, more preferably CR ≧ 3,000, and still more preferably CR ≧ 5,000. Similarly to the wavelength region of 440 nm ≦ λ ≦ 470 nm, sufficient brightness tends not to be obtained when Tp <30%, and light utilization efficiency is excellent when Tp ≧ 30%. Can be reduced. Tp ≧ 31% is preferable, and Tp ≧ 32% is more preferable.

  Furthermore, the polarizing element of the present invention preferably satisfies Tp ≧ 30% and CR ≧ 1,000 in the wavelength region of 470 nm <λ ≦ 490 nm. It is preferable to control the weak light emission of the blue LED or blue fluorescent tube having a maximum light emission output of 440 nm to 470 nm on the longer wavelength side. In the display of the display, the contrast decreases when CR <1,000 in the wavelength region. Preferably, CR ≧ 1,000, more preferably CR ≧ 2,500, and still more preferably CR ≧ 4,000. Similarly to the wavelength region of 440 nm ≦ λ ≦ 470 nm, sufficient brightness tends not to be obtained when Tp <30%, and light utilization efficiency is excellent when Tp ≧ 30%. Can be reduced. Tp ≧ 31% is preferable, and Tp ≧ 32% is more preferable.

  The polarizing element of the present invention contains at least a dichroic dye. Examples of the dichroic dye include iodine complexes and dichroic dyes.

（式中Ｒ_１、Ｒ_２は各々独立に水素原子、低級アルキル基、低級アルコキシル基を示し、ｎ＝１〜３を示す）When a dichroic dye is used as the dichroic dye used in the polarizing element of the present invention, at least one kind of dichroic dye (A) group and / or a dichroic dye represented by formula (1) ( B) is preferably used.
Dichroic dye (A) group Ai. direct. Orange 26
Sea. Ai. direct. Orange 39
Sea. Ai. direct. Orange 107
Dichroic dye (B)

(Wherein R ₁ and R ₂ each independently represents a hydrogen atom, a lower alkyl group or a lower alkoxyl group, and n = 1 to 3)

  The dichroic dyes (A) are all dyes exhibiting high dichroism, and the wavelength (λmax) showing the maximum contrast value is 420 nm ≦ λmax ≦ 460 nm. Above all, sea. Ai. direct. More preferably, orange 39 is used.

The dichroic dye (B) represented by the formula (1) is a dye exhibiting high dichroism and is characterized in that the wavelength (λmax) showing the maximum contrast value is 450 nm ≦ λmax ≦ 470 nm.
In formula (1), R ₁ and R ₂ are preferably hydrogen atoms. Moreover, it is preferable that it is a mixture which consists of a compound of n = 1-3, The ratio of the weight of the compound of n = 2 with respect to the total weight of the compound of n = 1 and n = 3 is 55% or more. More preferably, it is 65% or more, more preferably 75% or more, and most preferably 85% or more.
In addition, the dichroic dye (B) represented by the formula (1) can be synthesized by the method described in WO2007 / 138980.

  It is more preferable to use at least one dichroic dye (A) group and the dichroic dye (B) in combination. In general, polarizing elements obtained by using different dichroic dyes in combination tend to be lower than the optical characteristics of polarizing elements obtained by using each dichroic dye alone. The combination of at least one of the dichroic dyes (A) and the dichroic dye (B) in FIG. 2 does not impair the respective characteristics, and as a result, the characteristics of λmax are improved and high characteristics are obtained in a wide band. It can be expressed. Λmax of the obtained polarizing element is 440 nm ≦ λmax ≦ 470 nm, compared with the polarizing element obtained by using the dichroic dye (A) group or the dichroic dye (B), In the case of an equivalent Tp, a higher contrast value can be obtained, and in the case of an equivalent contrast value, a higher Tp value can be obtained. Further, a high contrast value can be obtained in a wider wavelength region.

  The mixing ratio of the dichroic dye (A) group and the dichroic dye (B) when the dichroic dye (A) group is used in combination with at least one kind and the dichroic dye (B) is particularly limited. The dichroic dye (B) is usually 25 to 400 parts by weight with respect to 100 parts by weight of the dichroic dye (A) group, preferably 100 parts by weight of the dichroic dye (A) group. On the other hand, the dichroic dye (B) is 50 to 200 parts by weight.

  The method for producing a polarizing element using these dichroic dyes is not particularly limited. For example, a film in which a polyvinyl alcohol film formed by adsorbing a dichroic dye is oriented is a dichroic dye. Film or element oriented by coating on a rubbed substrate film, or film or element by mixing a dichroic dye with a liquid crystalline resin and coating on a rubbed substrate film, 2 A film or element in which a chromatic dye is mixed with a liquid crystalline resin, applied to a base film and oriented by sharing, a film in which a dichroic dye is dyed and oriented on a film stretched and oriented in at least one axial direction, Examples thereof include a film in which a chromatic dye is mixed with a resin such as plastic and stretched and oriented in at least one axial direction. Preferably, it is a film in which a polyvinyl alcohol film formed by adsorbing a dichroic dye is oriented, and the highest contrast value can be obtained.

  The manufacturing method of the polyvinyl alcohol-type resin which comprises a polarizing element is not specifically limited, It can manufacture by a well-known method. For example, the polyvinyl alcohol resin can be obtained by saponifying a polyvinyl acetate resin. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids. The saponification degree of the polyvinyl alcohol resin is usually preferably from 85 to 100 mol%, more preferably 95 mol% or more. This polyvinyl alcohol-based resin may be further modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. Moreover, 1,000-10,000 are preferable normally and the polymerization degree of polyvinyl alcohol-type resin has more preferable 1,500-7,000.

  A film formed from such a polyvinyl alcohol resin is used as a raw film. The method for forming a polyvinyl alcohol-based resin is not particularly limited, and can be formed by a known method. In this case, the polyvinyl alcohol-based resin film can contain glycerin, ethylene glycol, propylene glycol, low molecular weight polyethylene glycol, or the like as a plasticizer. The amount of the plasticizer is preferably 5 to 20% by weight, and more preferably 8 to 15% by weight. Although the film thickness of the raw film which consists of polyvinyl alcohol-type resin is not specifically limited, For example, 5-150 micrometers is preferable and 10-100 micrometers is more preferable.

  The polyvinyl alcohol resin film is first subjected to a swelling step. A swelling process is performed by immersing a polyvinyl alcohol-type resin film for 30 second-10 minutes in a 20-50 degreeC solution. The solvent is preferably water. When the time for manufacturing the polarizing element is shortened, the swelling step can be omitted because the swelling occurs even during the dyeing process.

  After the swelling step, a dyeing step is performed. The dyeing step is performed by immersing the polyvinyl alcohol-based resin film in a solution containing a dichroic dye. The solution temperature in this step is preferably 5 to 60 ° C, more preferably 20 to 50 ° C, and particularly preferably 35 to 50 ° C. Although the time immersed in a solution can be adjusted moderately, it is preferable to adjust in 30 second-20 minutes, and 1-10 minutes are more preferable. The dyeing method is preferably immersed in the solution, but can also be performed by applying the solution to a polyvinyl alcohol-based resin film.

  The solution containing the dichroic dye can contain sodium chloride, sodium sulfate, anhydrous sodium sulfate, sodium tripolyphosphate and the like as a dyeing assistant. Their content can be adjusted at any concentration depending on the time and temperature depending on the dyeability of the dye, but the respective content is preferably 0 to 5% by weight, more preferably 0.1 to 2% by weight.

  After the dyeing process, a cleaning process (hereinafter referred to as cleaning process 1) can be performed before entering the next process. The washing step 1 is a step of washing the dye solvent adhering to the surface of the polyvinyl alcohol resin film in the dyeing step. By performing the washing step 1, it is possible to suppress the migration of the dye into the liquid to be processed next. In the cleaning step 1, water is generally used. The washing method is preferably immersed in the solution, but can be washed by applying the solution to a polyvinyl alcohol resin film. The time for washing is not particularly limited, but is preferably 1 to 300 seconds, more preferably 1 to 60 seconds. The temperature of the solvent in the washing step 1 needs to be a temperature at which the hydrophilic polymer does not dissolve. Generally, it is washed at 5 to 40 ° C.

  After the dyeing step or the washing step 1, a step of containing a crosslinking agent and / or a water resistance agent can be performed. Examples of the crosslinking agent include boron compounds such as boric acid, borax or ammonium borate, polyvalent aldehydes such as glyoxal or glutaraldehyde, polyisocyanate compounds such as biuret type, isocyanurate type or block type, titanium oxy Titanium compounds such as sulfate can be used, but ethylene glycol glycidyl ether, polyamide epichlorohydrin, and the like can also be used. Examples of the water-resistant agent include succinic peroxide, ammonium persulfate, calcium perchlorate, benzoin ethyl ether, ethylene glycol diglycidyl ether, glycerin diglycidyl ether, ammonium chloride or magnesium chloride, preferably boric acid. Used. The step of containing a crosslinking agent and / or a water-resistant agent is performed using at least one kind of crosslinking agent and / or a water-resistant agent shown above. As a solvent in that case, water is preferable, but it is not limited. The concentration of the cross-linking agent and / or water-proofing agent in the solvent in the step of adding the cross-linking agent and / or water-proofing agent is 0.1 to 6.0 with respect to the solvent when boric acid is used as an example. % By weight is preferable, and 1.0 to 4.0% by weight is more preferable. The solvent temperature in this step is preferably 5 to 70 ° C, more preferably 5 to 50 ° C. Although it is preferable to immerse the polyvinyl alcohol-based resin film in the solution with a crosslinking agent and / or a waterproofing agent, the solution may be applied to or applied to the polyvinyl alcohol-based resin film. The treatment time in this step is preferably 30 seconds to 6 minutes, and more preferably 1 to 5 minutes. However, it is not essential to contain a cross-linking agent and / or a water-resistant agent, and if it is desired to shorten the time, this processing step may be omitted if a cross-linking treatment or a water-resistant treatment is unnecessary. .

  After performing the dyeing process, the cleaning process 1, or the process of containing a crosslinking agent and / or a water resistance agent, the stretching process is performed. The stretching step is a step of stretching the polyvinyl alcohol film uniaxially. The stretching method may be either a wet stretching method or a dry stretching method.

  In the case of the dry stretching method, when the stretching heating medium is an air medium, the temperature of the air medium is preferably stretched at a room temperature to 180 ° C. Moreover, it is preferable to process in the atmosphere of 20 to 95% RH. Examples of the heating method include an inter-roll zone stretching method, a roll heating stretching method, a pressure stretching method, an infrared heating stretching method, and the like, but the stretching method is not limited. The stretching step can be performed in one step, but can also be performed by two or more multi-step stretching.

  In the case of the wet stretching method, stretching is performed in water, a water-soluble organic solvent, or a mixed solution thereof. It is preferable to perform the stretching treatment while being immersed in a solution containing a crosslinking agent and / or a water resistance agent. Examples of the crosslinking agent include boron compounds such as boric acid, borax or ammonium borate, polyvalent aldehydes such as glyoxal or glutaraldehyde, polyisocyanate compounds such as biuret type, isocyanurate type or block type, titanium oxy Titanium compounds such as sulfate can be used, but ethylene glycol glycidyl ether, polyamide epichlorohydrin, and the like can also be used. Examples of water-proofing agents include succinic peroxide, ammonium persulfate, calcium perchlorate, benzoin ethyl ether, ethylene glycol diglycidyl ether, glycerin diglycidyl ether, ammonium chloride, and magnesium chloride. Stretching is performed in a solution containing at least one or more crosslinking agents and / or waterproofing agents as described above. The crosslinking agent is preferably boric acid. For example, the concentration of the crosslinking agent and / or the water-proofing agent in the stretching step is preferably 0.5 to 15% by weight, and more preferably 2.0 to 8.0% by weight. The draw ratio is preferably 2-8 times, more preferably 5-7 times. The stretching temperature is preferably 40 to 60 ° C, and more preferably 45 to 58 ° C. The stretching time is usually 30 seconds to 20 minutes, but 2 to 5 minutes is more preferable. The wet stretching step can be performed in one step, but can also be performed by two or more steps.

  After performing the stretching step, the film surface may be subjected to a cleaning step (hereinafter referred to as a cleaning step 2) because the cross-linking agent and / or waterproofing agent may precipitate or foreign matter may adhere to the film surface. it can. The washing time is preferably 1 second to 5 minutes. The washing method is preferably immersed in a washing solution, but the solution can be washed on the polyvinyl alcohol resin film by coating or coating. The cleaning process can be performed in one stage, and the multi-stage process of two or more stages can be performed. Although the solution temperature of a washing | cleaning process is not specifically limited, Usually, 5-50 degreeC, Preferably it is 10-40 degreeC.

  Examples of the solvent used in the treatment steps so far include, for example, water, dimethyl sulfoxide, N-methylpyrrolidone, methanol, ethanol, propanol, isopropyl alcohol, glycerin, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, or triethylene glycol. Examples of the solvent include, but are not limited to, alcohols such as methylolpropane, and amines such as ethylenediamine or diethylenetriamine. A mixture of one or more of these solvents can also be used. The most preferred solvent is water.

  After the stretching process or the cleaning process 2, a film drying process is performed. The drying process can be performed by natural drying, but in order to further improve the drying efficiency, the surface can be removed by compression with a roll, an air knife, a water absorption roll, etc., and / or blow drying is performed. You can also As a drying process temperature, it is preferable to dry-process at 20-100 degreeC, and it is more preferable to dry-process at 60-100 degreeC. A drying treatment time of 30 seconds to 20 minutes can be applied, but 5 to 10 minutes is preferable.

  Furthermore, the polarizer of the present invention preferably has a transmittance of 2% or less in a wavelength region of 500 nm ≦ λ ≦ 560 nm. More preferably, the transmittance is 1% or less in a wavelength region of 540 nm ≦ λ ≦ 550 nm. A blue LED or blue fluorescent tube having a maximum light emission output of 440 nm to 470 nm may be accompanied by slight light emission around 550 nm. In this case, since slight light leakage occurs at the time of light shielding, it is preferable to control the light emission. In the display of the display, when the transmittance is 2% or more in the wavelength region, sufficient contrast tends not to be obtained. The transmittance is preferably 2% or less, and more preferably 1% or less in the wavelength region of 540 nm ≦ λ ≦ 550 nm.

  Moreover, you may have a polarization characteristic in the said wavelength range. In this case, Tc ≦ 2% is preferable in the wavelength region of 500 nm ≦ λ ≦ 560 nm, and more preferably Tc ≦ 1% in the wavelength region of 540 nm ≦ λ ≦ 550 nm.

  These production methods are not particularly limited, but a film obtained by orienting a polyvinyl alcohol film using a dichroic dye having a polarization characteristic in a wavelength region of 500 nm ≦ λ ≦ 560 nm, and a dichroic dye A film or element oriented by applying to a base film subjected to rubbing treatment, and a film or element oriented by applying to a base film subjected to rubbing treatment by mixing a dichroic dye with a liquid crystalline resin, A film or element in which a dichroic dye is mixed with a liquid crystalline resin, applied to a substrate film and oriented by sharing, a film in which a dichroic dye is dyed and oriented in a film oriented at least in one axial direction, In addition to a film that is obtained by mixing a dichroic dye with a resin such as plastic and stretching in at least one axial direction, a wavelength of 500 nm ≦ λ ≦ 560 nm For example, a method of bonding a film having a performance of 2% or less of transmittance in a wavelength region of 500 nm ≦ λ ≦ 560 nm to a polarizing plate having no polarization property in the region. A film obtained by orienting a polyvinyl alcohol film formed by adsorbing a dichroic dye is preferable, and Tp in a wavelength region of 420 nm ≦ λ ≦ 490 nm is not impaired.

  When a dichroic dye is used as the dichroic dye used in these, the dichroic dye is not particularly limited. Ai. direct. Red 79, Sea. Ai. direct. Red 81, Sea. Ai. direct. Violet 9, C. Ai. direct. Violet 35, C.I. Ai. direct. Violet 57, C.I. Ai. direct. Blue 67 etc. are mentioned. These are used in combination with the dichroic dye (A) group and / or the dichroic dye (B), but are not limited to one type of combination and may be used in combination.

  The blending amount of these dichroic dyes is not particularly limited, but is usually 25 to 300 parts by weight based on 100 parts by weight of the total amount of the dichroic dyes (A) and / or the dichroic dyes (B). It is.

  Further, the dichroic dye of the present invention may use other dichroic dyes as long as the polarization characteristics are not impaired. Such a dichroic dye is not particularly limited. Ai. direct. Yellow 12, sea. Ai. direct. Yellow 28, Sea. Ai. direct. Yellow 44 etc. are mentioned. Other than these dichroic dyes, other organic dyes can be used in combination as required. The blending ratio is not particularly limited.

  The polarizing element using the dichroic dye thus obtained is suitable as a polarizing element used in the display.

  When an iodine complex is used as the dichroic dye used in the changing element of the present invention, Tc (λ460) ≦ Tc (λ600) is preferable, and Tc (λ460) <Tc (λ600) is more preferable. A polarizing plate using a known iodine complex usually has Tc (λ460)> Tc (λ600), and a high contrast value cannot be obtained in a wavelength range of 500 nm or less. Moreover, although it is possible to obtain a high contrast value by increasing the density, Tp <30%, and sufficient brightness cannot be obtained. For these reasons, a polarizing plate using an iodine complex is not suitable as a polarizing plate used for the display. Therefore, when an iodine complex is used, it is preferable that Tc (λ460) ≦ Tc (λ600).

  The method for producing a polarizing element using an iodine complex and Tc (λ460) ≦ Tc (λ600) is not limited. For example, a polyvinyl alcohol film on which an iodine complex is adsorbed is oriented. A film is mentioned.

  The manufacturing method of the polyvinyl alcohol-type resin which comprises a polarizing element, and the film forming method of a polyvinyl alcohol-type resin are the same as the method as described when using a dichroic dye. Moreover, the polymerization degree of the polyvinyl alcohol-based resin is usually preferably from 1,000 to 10,000, and more preferably from 1,500 to 5,000.

  The polyvinyl alcohol resin film is first subjected to a swelling step. The swelling step is the same as the method described in the case of using a dichroic dye.

  After the swelling step, a dyeing step is performed. In the dyeing step, the polyvinyl alcohol resin film is treated with a solution containing iodine and iodide. The solvent of the solution is preferably water, but is not particularly limited. Examples of the iodide include, but are not limited to, an alkali metal iodide compound such as potassium iodide, ammonium iodide, cobalt iodide, or zinc iodide. Is preferably used, and potassium iodide is more preferably used. The iodine concentration is preferably 0.0001 to 0.5% by weight, and more preferably 0.001 to 0.4% by weight. The concentration of iodide is preferably 0.001 to 8% by weight. The solution temperature in this step is preferably 5 to 50 ° C, more preferably 10 to 40 ° C, and particularly preferably 20 to 30 ° C. Although the time immersed in a solution can be adjusted moderately, it is preferable to adjust in 30 second-6 minutes, and 1-5 minutes are more preferable. The dyeing method is preferably immersed in the solution, but can also be performed by applying or coating the solution on a polyvinyl alcohol resin film.

  In the treatment with iodine and iodide, a crosslinking agent and / or a water-proofing agent may be added to the solution. Usually, a crosslinking agent is used. Although it does not specifically limit as a crosslinking agent, Usually boric acid is preferable. For example, the concentration at which boric acid is added is preferably 0.1 to 5.0% by weight, and more preferably 2.0 to 4.0% by weight. In the case of a polyvinyl alcohol resin film containing iodine, iodide, a crosslinking agent and / or a water resistance agent, iodine, iodide, a crosslinking agent and / or a water resistance agent need not necessarily be included in the polyvinyl alcohol resin film. It is also included when it is contained in the film in a reacted form.

  Further, as described above, the crosslinking agent treatment step can be performed simultaneously with the dyeing step, but it is more preferable to perform the crosslinking agent treatment step after the dyeing step. The treatment method at that time is performed by treating the film obtained in the dyeing step with a solution containing a crosslinking agent. The treatment method with the crosslinking agent-containing solution is usually preferably a method of immersing a dyed film in the solution, but may be a method of applying or coating the solution on the film. The dipping can be performed before the stretching step or can be performed together with the stretching step. When the stretching method is a dry stretching method, it is preferable to perform a crosslinking agent treatment before stretching, and when the stretching method is a wet stretching method, it is preferably performed together with the stretching treatment. The crosslinking agent is the same as that described in the dichroic dye crosslinking agent treatment step. Moreover, you may make a water-resistant agent coexist in this crosslinking agent containing solution. The water-proofing agent is the same as that described in the water-proofing agent treatment step for the dichroic dye. The concentration of the crosslinking agent in the solvent is preferably 0.1 to 6.0% by weight, more preferably 1.0 to 4.0% by weight based on the solvent when boric acid is used as an example. The solvent temperature when performing before the stretching step in this step is preferably 5 to 60 ° C, more preferably 5 to 40 ° C when performing before stretching, and more preferably 45 to 58 ° C when performing together with stretching. The treatment time in this step is preferably 30 seconds to 6 minutes, and more preferably 1 to 5 minutes.

  The stretching step includes a dry stretching method and a wet stretching method. Examples of the stretching method are the same as those described in the stretching step of the dichroic dye.

  After the stretching treatment, a treatment with a solution containing a halide is performed. This process is a process aimed at adjusting the hue and improving the polarization characteristics. The treatment method is preferably a method of immersing the dyed film in the solution, and may be a method of applying or coating the solution on the film. Examples of the halide include alkali metal compounds such as potassium iodide and sodium iodide, iodides such as ammonium iodide, cobalt iodide and zinc iodide, alkali metal chloride compounds such as potassium chloride and sodium chloride, or It is preferably a chloride such as zinc chloride, and is preferably water-soluble. More preferred is iodide, more preferred is an alkali metal iodide compound, and particularly preferred is potassium iodide. The concentration of the halide is an important factor of Tc (λ460) ≦ Tc (λ600), and the concentration varies depending on the type, but is usually preferably 6.0 to 15.0% by weight, and 7.0 to 12%. The content is more preferably 0% by weight, and still more preferably 8.0 to 10.0% by weight. Although processing temperature changes also with the density | concentrations of a halide, 5-55 degreeC is preferable, for example, and 20-40 degreeC is more preferable. The treatment time varies depending on the halide concentration, but is preferably, for example, 1 second to 5 minutes, and preferably 5 to 30 seconds in view of the stability of the in-plane characteristics of the polarizing film. In addition, when the stretching step is performed by a wet stretching method, it is possible to perform a halide treatment together with the stretching step, but it is preferable to perform the halide treatment after the stretching treatment in terms of quality stability.

  Examples of the solvent for the treatment solution in the treatment steps so far include, but are not particularly limited to, water, alcohol solvents, or glycol solvents. Further, a mixed solvent of water and a water-soluble solvent may be used, such as a mixed solution of water and alcohol, a mixed solvent of dimethyl sulfoxide and water, or the like. Most preferred is water.

  After the halide treatment, the film is dried. The drying treatment method is the same as that described in the drying treatment method for the dichroic dye.

  The polarizing element using the iodine complex thus obtained is suitable as a polarizing element used in the display.

  The obtained polarizing element is made into a polarizing plate by providing a transparent protective layer as a support on one side or both sides. A transparent protective layer used for a polarizing element of a film in which a polyvinyl alcohol film is oriented can be provided as a coating layer made of a polymer or as a laminate layer of a film. The transparent protective layer used for the coating type polarizing element can be provided with the base material used for the coating substrate as it is as the transparent protective layer, or the protective layer can be provided by transferring the polarizing element to a film base material or the like. .

  The transparent protective layer is preferably a transparent polymer or film having high mechanical strength and good thermal stability. Substances used as the transparent protective layer include, for example, cellulose acetate resin such as triacetyl cellulose (TAC) and diacetyl cellulose or a film thereof, acrylic resin or a film thereof, polyvinyl chloride resin or a film thereof, polyester resin or a film thereof, poly Arylate resin or film thereof, cyclic polyolefin resin or film thereof using cyclic olefin such as norbornene as a monomer, polyethylene, polypropylene, polyolefin having cyclo or norbornene skeleton or copolymer thereof, main chain or side chain being imide and / or Alternatively, an amide resin or polymer or a film thereof may be used. In addition, a resin having liquid crystallinity or a film thereof can be provided as the transparent protective layer. The thickness of the protective film is, for example, about 0.5 to 200 μm. A polarizing plate is produced by providing one or more layers of the same or different types of resins or films on one side or both sides.

  As a substance used as a transparent protective layer, it is more preferable to use a PET film on at least one side. In the conventional LCD display, since an image is displayed on the characteristics of the LCD and the polarizing plate itself, a TAC film having high transparency and low birefringence is mainly used for the transparent protective layer. In some cases, a retardation film, which is a viewing angle compensation film, is directly used on one surface of the transparent protective layer. On the other hand, the role of the polarizing plate in the fluorescence excitation color conversion display in which the polarizing plate of the present invention is used is a light switching function, and it is not necessary to use the polarizing plate of the present invention as an image display surface. Accordingly, it is not necessary to use an expensive film such as a low-birefringence TAC film or a retardation film of a viewing angle compensation film, and it is more preferable to use a PET film that is inexpensive, has excellent mechanical properties, and has good workability. . Since the PET film has a large birefringence, when used as a double-sided support, the transmittance tends to decrease. Therefore, it is preferably used on a single-sided support or one side of a double-sided support. About arrangement | positioning of PET film as a polarizing plate support body in a display apparatus, it is preferable to arrange | position both an upper and lower polarizing plate on the opposite side to a liquid crystal layer with respect to a polarizing element. A PET film having an easy-adhesion layer is more preferred for the purpose of improving transmittance and improving adhesiveness. The easy-adhesion PET film is not particularly limited, and a commercially available product can be used. It is further preferable that the easy-adhesion layer is provided on both sides.

  If necessary, at least one layer of a material having a lower refractive index than that of the transparent protective layer may be provided on the transparent protective layer to form a reduced reflection transparent protective layer. By using the anti-reflection protective layer, the light transmission efficiency can be improved, and higher contrast values and Tp values can be obtained. The material having a refractive index lower than that of the transparent protective layer is not particularly limited, and examples thereof include organic materials such as acrylic resin and fluorine resin, and inorganic materials such as colloidal silica. Is also possible. Further, it may be a reaction system or a non-reaction system. These processing methods are not particularly limited, and examples thereof include a vapor deposition method, a sputtering method, and various coating methods. Moreover, it is also possible to laminate | stack multilayers, such as a hard-coat layer and a high refractive index layer, on a transparent protective layer as needed.

  In order to bond the transparent protective layer to the polarizing element, an adhesive is required. Although it does not specifically limit as an adhesive agent, A polyvinyl alcohol-type adhesive agent is preferable. Examples of the polyvinyl alcohol adhesive include, but are not limited to, Gohsenol NH-26 (manufactured by Nippon Gosei Co., Ltd.), EXEVAL RS-2117 (manufactured by Kuraray Co., Ltd.), and the like. A cross-linking agent and / or a waterproofing agent can be added to the adhesive. As the polyvinyl alcohol-based adhesive, a maleic anhydride-isobutylene copolymer is used, but an adhesive mixed with a crosslinking agent can be used if necessary. As maleic anhydride-isobutylene copolymer, for example, isoban # 18 (manufactured by Kuraray), isoban # 04 (manufactured by Kuraray), ammonia-modified isoban # 104 (manufactured by Kuraray), ammonia-modified isoban # 110 (manufactured by Kuraray) ), Imidized isoban # 304 (manufactured by Kuraray), imidized isoban # 310 (manufactured by Kuraray), and the like. A water-soluble polyvalent epoxy compound can be used as the crosslinking agent at that time. Examples of the water-soluble polyvalent epoxy compound include Denacol EX-521 (manufactured by Nagase Chemtech) and Tetrat-C (manufactured by Mitsui Gas Chemical Co., Ltd.). Moreover, as adhesives other than polyvinyl alcohol-type resin, well-known adhesives, such as urethane type, an acrylic type, and an epoxy type, can also be used. Further, for the purpose of improving the adhesive strength of the adhesive or improving the water resistance, additives such as zinc compounds, chlorides, iodides and the like can be simultaneously contained at a concentration of about 0.1 to 10% by weight. The additive is not limited. After laminating the transparent protective layer with an adhesive, the polarizing plate is obtained by drying or heat treatment at a suitable temperature.

  Moreover, you may use an adhesive for bonding of a transparent protective layer and a polarizing element. The pressure-sensitive adhesive is not particularly limited, and a preferable example is an acrylic pressure-sensitive adhesive. The thickness can be arbitrarily selected from the viewpoints of characteristics such as adhesive strength and transmittance, and the overall thickness, but is usually in the range of 5 to 50 μm, preferably in the range of 10 to 30 μm. .

  The polarizing plate of the present invention may be a polarizing plate with a support. In order to attach a polarizing plate, the support preferably has a flat portion, and since it is used for optical purposes, a glass molded product is preferable. Examples of the glass material include soda glass, borosilicate glass, inorganic substrate made of quartz, inorganic glass such as inorganic substrate made of sapphire, and organic plastic plates such as acrylic and polycarbonate. Glass is preferred. The glass plate may have a desired thickness and size. In addition, the polarizing plate with glass may be provided with a low reflection layer on the glass surface in order to further improve the single plate light transmittance.

  Moreover, although an adhesive agent, an adhesive, etc. are used for bonding of the said support body and a polarizing element or a polarizing plate, it does not specifically limit, An acrylic adhesive is mentioned as a preferable example. The thickness can be arbitrarily selected from the viewpoints of characteristics such as adhesive strength and transmittance, and the overall thickness, but is usually in the range of 5 to 50 μm, preferably in the range of 10 to 30 μm. .

  The polarizing element and polarizing plate of the present invention thus obtained have a wavelength range of 440 nm ≦ λ ≦ 470 nm, Tp ≧ 30%, and CR ≧ 8,000 in the wavelength region between any continuous 20 nm, and the remaining wavelength region CR ≧ 5,000, and is suitable as a polarizing element and a polarizing plate used in a fluorescence excitation color conversion display using a blue LED or a blue fluorescent tube having a maximum light emission output of 440 nm to 470 nm as a light source.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these. In addition, the transmittance | permeability shown in an Example was performed as follows.

  When measuring the transmittance using a spectrophotometer (“V-7100” manufactured by JASCO Corporation), on the light exit side, after the visibility correction based on JIS-Z8701 (C light source 2 ° field of view). C light source light having a transmittance of 100% can be incident on the measurement sample.

  The parallel (parallel Nicol) spectral transmittance obtained by making the C light source light incident on the two polarizing plates of the present invention and making the absorption axis directions of the two polarizing plates parallel to each other is Tp, and the polarizing plate 2 The orthogonal (cross Nicol) spectral transmittance obtained by measuring so that the absorption axis directions of the sheets were orthogonal was defined as Tc. The contrast is a contrast based on the spectral transmittance, and represents a value consisting of CR = Tp / Tc.

  Each transmittance was measured using a spectrophotometer [“V-7100” manufactured by JASCO Corporation].

Example 1
A 75-μm-thick polyvinyl alcohol resin film (VF series manufactured by Kuraray Co., Ltd.) having a saponification degree of 99% or more was immersed in warm water at 40 ° C. for 3 minutes for swelling treatment. The film subjected to the swelling treatment was treated with a dichroic dye (A) group pigment, C.I. Ai. direct. Orange 39 was immersed in an aqueous solution at 45 ° C. containing 0.04% by weight, sodium tripolyphosphate 0.1% by weight and sodium sulfate 0.1% by weight, dyed, and adsorbed onto a polyvinyl alcohol film. . The film on which the dye was adsorbed was washed with water, and after washing, it was treated with boric acid for 1 minute with a 40 ° C. aqueous solution containing 2 wt% boric acid. The film obtained by the boric acid treatment was treated for 5 minutes in an aqueous solution at 55 ° C. containing 3% by weight of boric acid while stretching 5.0 times. While maintaining the tension of the film obtained by the boric acid treatment, the film was treated with water at room temperature for 15 seconds. The film obtained by the treatment was immediately dried at 70 ° C. for 9 minutes to obtain a polarizing element having a thickness of 25 μm. Thickness of the obtained polarizing element using a 100 μm-thick PET film (Cosmo Shine A4300 manufactured by Toyobo Co., Ltd.), a polyvinyl alcohol-based adhesive, and an acrylic pressure-sensitive adhesive having a thickness of 20 μm provided with a double-sided easy-adhesion layer. It laminated | stacked by the structure of PET / adhesion layer / polarizing element / adhesion layer / glass on a 1 mm glass substrate, and it laminated and obtained the polarizing plate, and it was set as the measurement sample.

Example 2
The dye to be adsorbed is a dye represented by the formula (1) which is a dichroic dye (B), wherein R ₁ and R ₂ are hydrogen atoms, and the ratio of n measured by HPLC is n A polarizing plate was prepared in the same manner as in Example 1 except that 0.02% by weight of a pigment composed of 33% = 1, 65% n = 2, and 2% n = 3 was used as a measurement sample.

Example 3
As a pigment to be adsorbed, a pigment of the dichroic dye (A) group, C.I. Ai. direct. A pigment represented by the formula (1) that is 0.018% by weight of orange 39 and a dichroic dye (B), wherein R ₁ and R ₂ are hydrogen atoms, and n is measured by HPLC A polarizing plate was prepared and measured in the same manner as in Example 1 except that 0.015% by weight of a dye having a ratio of n = 1 of 33%, n = 2 of 65%, and n = 3 of 2% was used. A sample was used.

Example 4
As a pigment to be adsorbed, a pigment of the dichroic dye (A) group, C.I. Ai. direct. Orange 39 is a pigment represented by the formula (1) that is 0.01% by weight and the dichroic dye (B), wherein R ₁ and R ₂ are hydrogen atoms, and the ratio of n measured by HPLC 0.01% by weight of a dye comprising 33% n = 1, 65% n = 2, 2% n = 3, and C.I. Ai. direct. A polarizing plate was produced in the same manner as in Example 1 except that 0.02% by weight of red 81 was used, and used as a measurement sample.

Example 5
A 75-μm-thick polyvinyl alcohol resin film (VF series manufactured by Kuraray Co., Ltd.) having a saponification degree of 99% or more was immersed in warm water at 40 ° C. for 3 minutes for swelling treatment. The swelling-treated film is immersed in an aqueous solution at 30 ° C. containing 2.8% by weight of boric acid, 0.044% by weight of iodine, and 3.13% by weight of potassium iodide, and is dyed and adsorbed onto a polyvinyl alcohol film. It was. The film dyed with the dye was stretched 5.0 times and treated in an aqueous solution at 50 ° C. containing 3.0% by weight of boric acid for 5 minutes. While maintaining the tension of the film obtained by the boric acid treatment, a complementary color treatment was performed for 20 seconds with a 30 ° C. aqueous solution containing 8.0% by weight of potassium iodide. The film obtained by the treatment was immediately dried at 70 ° C. for 9 minutes to obtain a polarizing element having a thickness of 25 μm. Using the obtained polarizing element, a PET film (Cosmo Shine A4300 manufactured by Toyobo Co., Ltd.) having a double-sided easy-adhesion layer, a polyvinyl alcohol-based adhesive, and an acrylic pressure-sensitive adhesive having a thickness of 20 μm. It laminated | stacked by the structure of PET / adhesion layer / polarizing element / adhesion layer / glass on a 1 mm glass substrate, and it laminated and obtained the polarizing plate, and it was set as the measurement sample.

Comparative Example 1
A glass substrate with a thickness of 1 mm using an acrylic pressure-sensitive adhesive having a thickness of 20 μm and an iodine-based polarizing plate, the transparent protective layer of which is a double-sided TAC film, taken from a commercially available liquid crystal television (AQUAOS / 32 type manufactured by Sharp Corporation). To obtain a measurement sample.

Comparative Example 2
A polarizing plate was produced as a measurement sample in the same manner as in Example 4 except that the complementary color treatment was performed for 20 seconds with an aqueous solution containing 5.0% by weight of potassium iodide at 30 ° C.

FIG. 1 shows Tp and FIG. 2 shows Tp of spectroscopic measurement values for each wavelength of 5 nm obtained by measuring the measurement samples obtained in Examples 1-5 and Comparative Examples 1-2. Table 4 shows the Tp of each wavelength at 420 to 490 nm, Table 5 shows the contrast value, and Table 6 shows the Tc of each wavelength at 500 to 560 nm. Table 7 shows values of Tc (460) and Tc (600) of Example 5 and Comparative Examples 1 and 2 which are iodine-based polarizing plates.

  1-2 and Tables 4-5, the polarizing plates using the dichroic dyes of Examples 1 to 4 have high Tp and high contrast in the wavelength region of 420 to 490 nm, particularly 440 to 470 nm. It can be seen that this is excellent in the wavelength region. Furthermore, it can be seen from Table 6 that Tc is low in the wavelength region of 500 to 560 nm of Example 4. Among them, the polarizing plate using the dichroic dye (A) and the dichroic dye (B) of Examples 3 and 4 has a wide high contrast band and is very excellent in the wavelength range of 440 to 470 nm. Recognize. Further, it can be seen from Table 7 that the iodine-based polarizing plate of Example 5 is Tc (460) ≦ Tc (600), which is inferior to the polarizing plate using the dichroic dyes of Examples 1 to 3, but 440 In the wavelength region of ˜470 nm, Tp was high and the contrast was high.

  On the other hand, the known ordinary iodine-based polarizing plates of Comparative Examples 1 and 2 show that Tc (460)> Tc (600) from Table 7, and from the results of FIGS. 1-2 and Tables 4-5. As can be seen, in the wavelength region of 420 to 490 nm, particularly in the wavelength region of 460 nm or less, Tp was low and the contrast was not sufficient.

Industrial applicability

  It is excellent in polarization characteristics in the wavelength region of 440 nm ≦ λ ≦ 470 nm and used as a polarizing element and a polarizing plate used in a fluorescence excitation color conversion display using a blue LED or a blue fluorescent tube having a maximum light emission output of 440 nm to 470 nm as a light source. it can.

Claims (9)

In the wavelength region of 440 nm ≦ λ ≦ 470 nm, Tp ≧ 30%, and CR ≧ 8,000 in any wavelength region between 20 nm in the wavelength region, CR ≧ 5 in the remaining wavelength region in the wavelength region 000, containing at least a dichroic dye, wherein the dichroic dye contains at least one kind of dichroic dye (A) group and the dichroic dye (B) represented by the formula (1) A polarizing element used for a fluorescence excitation color conversion display using a blue LED or a blue fluorescent tube having a maximum light emission output of 440 nm to 470 nm as a light source.
Here, λ represents a wavelength, Tp is a spectral transmittance (transmittance at the time of parallel Nicols) when two polarizing elements are overlapped in parallel, and Tc is two polarizing elements. Is a spectral transmittance (transmission at the time of crossed Nicols) when the absorption axes are overlapped at right angles, and CR is an abbreviation of contrast and indicates a value consisting of Tp / Tc.
Dichroic dyes (A) group
Sea. Ai. direct. Orange 26
Sea. Ai. direct. Orange 39
Sea. Ai. direct. Orange 107
Dichroic dye (B)

(Wherein R ₁ and R ₂ each independently represents a hydrogen atom, a lower alkyl group or a lower alkoxyl group, and n = 1 to 3)   2. The polarizing element according to claim 1, wherein Tp ≧ 30% and CR ≧ 1,500 in a wavelength region of 420 nm ≦ λ <440 nm.   The polarizing element according to claim 1, wherein Tp ≧ 30% and CR ≧ 1,000 in a wavelength region of 470 nm <λ ≦ 490 nm. 4. The polarized light according to claim 1, wherein the ratio of the dichroic dye (B) to 100 parts by weight of the dichroic dye (A) group is 25 to 400 parts by weight. element.   5. The polarizing element according to claim 1, wherein the transmittance is 2% or less in a wavelength region of 500 nm ≦ λ ≦ 560 nm. In the wavelength region of 440 nm ≦ λ ≦ 470 nm, Tp ≧ 30%, and CR ≧ 8,000 in any wavelength region between 20 nm in the wavelength region, CR ≧ 5 in the remaining wavelength region in the wavelength region 000, containing at least a dichroic dye, the dichroic dye being an iodine complex, and Tc (λ460) ≦ Tc (λ600), wherein the maximum emission output is 440 nm to 470 nm A polarizing element used in a fluorescence excitation color conversion display using a blue LED or a blue fluorescent tube as a light source .
Here , λ represents a wavelength, Tp is a spectral transmittance (transmittance at the time of parallel Nicols) when two polarizing elements are overlapped in parallel, and Tc is two polarizing elements. Is the spectral transmittance (transmissivity at the time of crossed Nicols) when the respective absorption axes are orthogonally crossed, CR is an abbreviation of contrast and indicates a value consisting of Tp / Tc, and Tc (λ460) is the polarizing element 2 It is the spectral transmittance at 460 nm when the sheets are stacked with their respective absorption axes orthogonal (cross Nicol), and Tc (λ600) is the value when the two polarizing elements are stacked with their respective absorption axes orthogonal (cross) (Nicol) at 600 nm. Polarizer ing provided support film on at least one side of the polarizing element according to any one of claims 1 to 6.   The polarizing plate according to claim 7, wherein at least one surface of the support film is a PET (polyester) film.   A polarizing plate with an inorganic substrate, wherein the polarizing element according to any one of claims 1 to 6 or the polarizing plate according to claim 7 or 8 is laminated on an inorganic substrate.

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